JP4583430B2 - Wireless communication system - Google Patents

Description

  The present invention is a wireless communication system intended to dynamically use a frequency (spectrum).

In recent years, with the development of wireless communication, efficient use of frequency (spectrum) has been demanded.
In a conventional system for frequency use, a license is given to a user for each frequency band, and use of the frequency band is permitted only in a wireless communication system or a broadcast system provided by the user.

However, in the conventional system, there are frequency bands that are used with limited use time and area. In such a case, a user who is not licensed is not permitted to use the frequency outside the range of the time or area being used (out of time or outside the area).
Further, even a user of that frequency is not permitted to use that frequency band in a wireless communication system that is not licensed. For example, the frequency for TV broadcasting is used only in a limited area around the transmitting station / relay station.
In such a case, even outside the TV broadcasting area, other vendors cannot use this frequency band. In addition, it is not allowed to be used for purposes other than TV broadcasting.

  In order to make such a conventional system for frequency use more flexible, the following concepts are attracting attention. In other words, the concept is that a frequency band used in a radio communication system (primary system) to which a license is assigned is assigned a license outside the range of time and area in which the frequency band is used. No wireless communication system (secondary system) is used (see, for example, Patent Documents 1 and 2).

Here, in order to make it possible to use the frequency for each time or for each area, it is necessary to control the use of the frequency so that the secondary system does not interfere with the primary system.
Such control is divided into centralized control and distributed control.
Centralized control is control that centrally manages information related to frequency use and determines whether or not the frequency can be used. For example, a control station that manages all information related to the frequency usage status (usage time and area information) by the primary system is installed, and the control station determines whether or not the frequency band can be used for each time or area.
On the other hand, in the distributed control, the secondary system independently determines whether the frequency can be used. For example, a wireless communication station belonging to the secondary system implements a sensing function that detects the presence or absence of radio waves transmitted from the wireless communication station belonging to the primary system, and determines whether or not the frequency to be used is available. A radio communication system that enables flexible frequency use based on such distributed control is called cognitive radio.
JP 2006-94001 A JP 2006-94002 A

However, in the control related to the use of the frequency, if the control for determining whether or not the frequency is used is incomplete, there is a possibility that interference from the secondary system to the primary system may occur.
That is, in the centralized control, the information on the usage status of the frequency used in the control includes the information such as the required reception power level and QoS of the wireless system, the transmission power level of the wireless station, the communication method, geographical information, There is a lot of information such as a wide variety of information such as radio wave propagation environment. It is necessary to determine whether or not the frequency can be used from all these pieces of information, and it is difficult to accurately control whether or not the frequency can be used.
In distributed control (cognitive radio), since the secondary system independently determines the availability of the frequency by the sensing function, all information regarding the usage status of the frequency band cannot be used. Becomes lower. For example, when there is no information such as required reception power and QoS in the primary system, radio transmission power level, and communication method, the sensing function must determine whether or not the frequency can be used only from the reception power level. At this time, if the radio wave intensity transmitted from the primary system is weak due to the shadowing phenomenon where the radio wave intensity is weakened by obstacles, etc., the received power level may be low and an erroneous determination may be made. is there. Furthermore, there is a possibility that a failure occurs in the device that realizes the sensing function, and an error occurs in the frequency availability determination.

  The present invention has been made in view of such circumstances, and can easily and reliably prevent interference from the secondary system to the primary system, thereby improving the communication quality of the primary system. An object of the present invention is to provide a wireless communication system.

In order to solve the above problems, the present invention provides the following means.
The present invention is a wireless communication system having a primary wireless communication station that can preferentially use a frequency and a secondary wireless communication station that uses the frequency within a range that does not interfere with communication of the primary wireless communication station. The primary radio communication station detects interference from the secondary radio communication station or a secondary radio terminal connected to the secondary radio communication station and generates interference information, and the primary radio communication station is generated by the interference detection unit. Interference information transmitting means for transmitting the received interference information to the secondary wireless communication station, wherein the secondary wireless communication station stops interference based on the interference information transmitted from the interference information transmitting means comprising means, the primary wireless communication station, has information about the self and the secondary wireless communication station The primary wireless communication station, to expand the range for transmitting the interference information to send the interference information to the secondary radio communication stations existing within a predetermined distance from the self, the interference detection means does not detect an interference Features.

In addition, the present invention provides a radio communication system having a primary radio communication station that can preferentially use a frequency and a secondary radio communication station that uses the frequency within a range that does not interfere with communication of the primary radio communication station. The primary wireless communication station detects interference from the secondary wireless communication station and generates interference information, and the interference information generated by the interference detection means is transmitted to the secondary wireless communication station. Interference information transmitting means for transmitting to the secondary wireless communication station, and the secondary wireless communication station includes interference avoiding means for avoiding interference based on the interference information transmitted from the interference information transmitting means. The number of interference avoidance hops indicating the range of the secondary wireless communication station instructing avoidance is included, and the secondary wireless communication station Depending on the number of hops, and outputs the interference avoidance instruction to other secondary wireless communication station, wherein the primary wireless communication station, and wherein said interference detection means to expand the number of the interference avoidance hop until no detected interference To do.

  Further, the present invention, the primary radio communication station has information about itself and the secondary radio communication station, and an interference station specifying means for specifying a secondary radio communication station that is a cause of interference from the interference information, The primary wireless communication station transmits the interference information to the secondary wireless communication station that is the cause of the interference specified by the interference station specifying means.

  In the present invention, the interference station specifying means may be configured such that the position of each wireless communication station, transmission power, cell radius, identifier in data being communicated by the secondary wireless communication station, or communication being performed by the secondary wireless communication station. An interfering station is specified from a specific pattern in the data.

  In the present invention, the interference avoiding means may be a means for changing at least one of a communication frequency, a communication scheme, a modulation scheme, transmission power, antenna directivity, and polarization of the secondary wireless communication station, or It is means for stopping the operation of the secondary wireless communication station.

  Further, in the present invention, the radio communication system of the primary radio communication station and the secondary radio communication station is a CDMA communication system, and the interference avoidance means is means for changing a spreading code of the secondary radio communication station. It is characterized by.

  Also, the present invention is characterized in that the interference detecting means measures at least one of a received power level, an error rate, a throughput, a received signal spectrum, and a received signal periodicity.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the interference from a secondary system to a primary system can be prevented easily and reliably, and the communication quality of a primary system can be improved.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a wireless communication system in the present embodiment.
The radio communication system 100 does not interfere with communication between the primary radio base station (primary radio communication station) 1 including a base station apparatus that can preferentially use a specific frequency, and the communication of the primary radio base station 1. Secondary radio base stations (secondary radio communication stations) 21, 22, 23, and 24 having base station devices that use the frequencies in the range.
In addition, the radio communication system 100 includes a management station 3 having devices for managing the primary radio base station 1 and the secondary radio base stations 21, 22, 23, and 24, and a primary radio that is wirelessly connected to the primary radio base station 1. Terminals (primary wireless communication stations) 1a, 1b and secondary wireless terminals wirelessly connected to the secondary wireless base stations 21, 22, 23, 24 (for example, secondary wireless terminals 2a wirelessly connected to the secondary wireless base station 21, Secondary wireless communication station). Note that a plurality of secondary wireless terminals are wirelessly connected to the secondary wireless base stations 21, 22, 23, and 24, respectively, but are not shown in FIG.

The primary radio base station 1, the secondary radio base stations 21, 22, 23, and 24 and the management station 3 are connected to each other by signal lines. The primary radio base station 1, the secondary radio base stations 21, 22, 23, and 24, and the management station 3 communicate (transmit / receive) information via signal lines.
In addition, the primary radio base station 1 and the secondary radio base stations 21, 22, 23, and 24 communicate with each radio terminal wirelessly connected in each service area using the same frequency band. Shall be.

A system including the primary radio base station 1 and the primary radio terminals 1a and 1b is referred to as a primary system, and a system including the secondary radio base stations 21, 22, 23 and 24 and the secondary radio terminal 2a is referred to as a secondary system.
The wireless communication system 100 of this embodiment constitutes an IP network, and the primary wireless base station 1, the secondary wireless base stations 21, 22, 23, and 24 and the management station 3 are uniquely assigned IP addresses. Yes. Communication between arbitrary radio base stations is possible by using an IP address in communication.

The management station 3 manages the identifiers of the primary radio base station 1 and the secondary radio base stations 21, 22, 23, and 24, the installation location, the range of the non-interference area, and the information on the use frequency band.
Here, the non-interference area is an area set to prevent interference between service areas of each radio base station (primary radio base station 1 and secondary radio base stations 21, 22, 23, 24). As long as there is no overlap between non-interference areas, interference does not occur between service areas of each radio base station. The size of the non-interference area mainly depends on the transmission power of each radio base station and each radio terminal.

In this embodiment, it is assumed that each radio base station transmits radio waves at the same transmission power level, and the service area and non-interference area of each radio base station are the same.
When the radio base station is newly started or periodically, the non-interference area range information and the use frequency band of the radio base station are transmitted to the management station 3. Each wireless terminal existing in the service area of each wireless base station connects to the network via each wireless base station and performs normal application communication (user application communication). In FIG. 1, the primary radio base station 1 and the secondary radio base stations 21, 22, and 23 are in operation, and the secondary radio base station 24 is not in operation.

FIG. 2 is a block diagram showing the primary wireless terminal 1a.
Since the primary radio terminals 1a and 1b have the same configuration, only the primary radio terminal 1a will be described here as a representative.
The primary radio terminal 1a includes an antenna 1a1 that transmits and receives radio signals, a radio signal processing unit 1a6 that performs conversion between radio signals and digital signals, and reception level observation that observes (detects) reception levels (reception power levels). Part (interference detection means) 1a2.
Further, the primary radio terminal 1a includes a comparator (interference detecting means) 1a3 that compares a reception level with a preset threshold value, and a base station-terminal interface unit that generates an interference information packet under a predetermined condition. 1a4 and a switch 1a5 that selectively switches the connection point.
The interference information packet includes information indicating that there is interference.

Under such a configuration, the radio signal is received by the antenna 1a1, and the radio signal processing unit 1a6 reads the radio signal and converts it into a digital signal. Then, the radio signal processing unit 1a6 outputs the digital signal as a reception signal to the reception level observation unit 1a2. The reception level observation unit 1a2 observes the reception level of the received signal and outputs it to the comparator 1a3. The comparator 1a3 compares the reception level with a preset threshold value, and outputs the comparison result to the base station-terminal interface unit 1a4. Based on the comparison result, the base station-terminal interface unit 1a4 generates an interference information packet when the reception level exceeds the threshold, and performs radio signal processing on the interference information packet via the switch 1a5. To the unit 1a6. The radio signal processing unit 1a6 transmits the interference information packet to the primary radio base station 1 via the antenna 1a1.
The switch 1a5 connects the base point and the connection point A during transmission of the interference information packet, and connects the base point and the connection point B during normal application communication.

FIG. 3 is a block diagram showing the primary radio base station 1.
The primary radio base station 1 includes an antenna 11 that transmits and receives radio signals, a radio signal processing unit 12 that performs conversion between radio signals and digital signals, and a packet identification unit 13 that identifies each packet.
In addition, the primary radio base station 1 includes a base station-terminal interface unit 14 that analyzes interference information packets, and an inter-base station interface for communicating with the management station 3 and the secondary radio base stations 21, 22, 23, and 24. Unit (interference information transmitting means) 15.

  Under such a configuration, the radio signal transmitted from the primary radio terminals 1a and 1b is received by the antenna 11, and the radio signal processing unit 12 reads the radio signal and converts it into a digital signal. Then, the radio signal processing unit 12 outputs the digital signal as a packet to the packet identification unit 13. The packet identification unit 13 identifies whether the packet is an interference information packet or an application communication packet. The packet identification unit 13 connects the base point and the connection point B when the packet is an application communication packet, and outputs the application communication packet to the network. When the packet is an interference information packet, the packet identification unit 13 connects the base point and the connection point A. And the interference information packet is output to the base station-terminal interface unit 14.

The base station-terminal interface unit 14 analyzes the interference information packet and outputs the analysis result to the base station interface unit 15 as interference information.
When the inter-base station interface unit 15 reads the interference information output from the base station-terminal interface unit 14, the inter-base station interface unit 15 transmits an identifier request signal for requesting an identifier of the secondary radio base station that is causing interference through the signal line. To the management station 3. Further, when the identifier (identifier of the radio base station giving interference) output from the management station 3 is input, the inter-base station interface unit 15 receives the secondary radio base station 21 (or 22, 23) having the identifier. 24), the interference information is output via the signal line.

FIG. 4 is a block diagram showing the secondary radio base station 21.
Since the secondary radio base stations 21, 22, 23, and 24 have the same configuration, only the secondary radio base station 21 will be described here as a representative.
The secondary radio base station 21 includes an antenna 211 that transmits and receives radio signals, a radio signal processing unit (interference avoiding means) 212 that performs conversion between radio signals and digital signals, and a switch 213 that selectively switches connection points. And.
Further, the secondary radio base station 21 receives the interference information output from the primary radio base station 1 and performs inter-base station interface unit (interference avoiding means) 215 that performs operation stop control, and this inter-base station interface unit 215. When the operation stop control is performed, a base station-terminal interface unit (interference avoiding means) 214 that outputs an operation stop packet is provided.

With this configuration, the inter-base station interface unit 215 performs operation stop control on the radio signal processing unit 212 when the interference information output from the primary radio base station 1 is input (operation stop control). And an operation stop instruction is output to the base station-terminal interface unit 214. When reading the operation stop instruction, the base station-terminal interface unit 214 generates an operation stop packet and outputs the operation stop packet to the radio signal processing unit 212 via the switch 213. When the radio signal processing unit 212 reads the operation stop control instruction output from the inter-base station interface unit 215 and reads the operation stop packet output from the base station-terminal interface unit 214, the radio signal processing unit 212 wirelessly transmits the operation stop packet. As a signal, the signal is transmitted to the secondary wireless terminal 2a, and the communication process is stopped.
Note that the switch 213 connects the base point and the connection point A during operation stop packet transmission, and connects the base point and the connection point B during normal application communication.

FIG. 5 is a block diagram showing the secondary wireless terminal 2a.
Although a plurality of secondary wireless terminals are connected, the configuration of each secondary wireless terminal is the same as each other, and therefore only the secondary wireless terminal 2a will be described here as a representative.
The secondary radio terminal 2a includes an antenna 2a1 that transmits and receives radio signals, and a radio signal processing unit 2a2 that performs conversion between radio signals and digital signals.
The secondary wireless terminal 2a includes a packet identification unit 2a4 that identifies each packet and a base station-terminal interface unit 2a3 that performs operation stop control.

  With this configuration, when the antenna 2a1 receives a radio signal transmitted from the secondary radio base station 21, the radio signal processing unit 2a2 reads the radio signal and converts it into a digital signal. Then, the radio signal processing unit 2a2 outputs the digital signal as a packet to the packet identification unit 2a4. The packet identification unit 2a4 identifies whether the packet is an application communication packet or an operation stop packet. When the packet is an application communication packet, the packet identification unit 2a4 connects the base point and the connection point B, and outputs the application communication packet to the upper layer processing unit. When the packet is an operation stop packet, the packet identification unit 2a4 connects to the base point. The point A is connected, and the operation stop packet is output to the base station-terminal interface unit 2a3. The base station-terminal interface unit 2a3 analyzes the operation stop packet and outputs an operation stop control instruction to the radio signal processing unit 2a2. When the wireless signal processing unit 2a2 reads the operation stop control instruction, the wireless signal processing unit 2a2 stops the communication process.

Next, the operation of the wireless communication system 100 configured in this way in the present embodiment will be described.
First, the operation of the primary wireless terminal 1a will be described.
Since the operations of the primary radio terminals 1a and 1b are the same as each other, only the operation of the primary radio terminal 1a will be described here as a representative.
FIG. 6 is a flowchart showing the operation of the primary wireless terminal 1a.
The primary radio terminal 1a periodically performs processing (interference detection processing) for detecting interference received from the secondary radio base stations 21, 22, 23, 24 or the secondary radio terminal 2a in addition to normal application communication. Yes.

That is, the radio signal processing unit 1a6 of the primary radio terminal 1a sets a timer provided therein for performing interference detection processing (step S1). Then, the wireless signal processing unit 1a6 determines whether or not the timer has expired (step S2), and when determining that the timer has not expired (step S2; NO), repeats the process of step S2. On the other hand, when determining that the timer has expired (step S2; YES), the wireless signal processing unit 1a6 stops normal application communication (step S3). As a result, normal application communication is stopped synchronously between the primary radio base station 1 and all primary radio terminals in the service area.
Then, the primary radio terminal 1a observes the reception level (step S4). Specifically, the reception level observation unit 1a2 detects the reception power level from the reception signal output from the radio signal processing unit 1a6.

Further, the primary wireless terminal 1a compares the reception level with a threshold value (step S5), and determines whether the reception level exceeds the threshold value (step S6). Specifically, the comparator 1a3 compares the reception level output from the reception level observation unit 1a2 with a preset threshold value, and outputs the comparison result to the base station-terminal interface unit 1a4. Note that the threshold is set to, for example, -100 dBm.
If the primary radio terminal 1a determines that the reception level exceeds the threshold (step S6; YES), the primary radio terminal 1a transmits an interference information packet to the primary radio base station 1 (step S7), and ends the process. Specifically, the base station-terminal interface unit 1a4 generates an interference information packet when the reception level exceeds the threshold in the comparison result output from the comparator 1a3, and the interference information packet is The data is output to the wireless signal processing unit 1a6 via 1a5. The radio signal processing unit 1a6 transmits the interference information packet to the primary radio base station 1 via the antenna 1a1.
On the other hand, if the reception level does not exceed the threshold (step S6; NO), the primary wireless terminal 1a ends the process.

Next, a process (operation stop process) for stopping the operation of the secondary radio base station that interferes with the primary radio terminal will be described.
FIG. 7 is a flowchart showing an operation stop operation of the wireless communication system 100.
Here, the secondary radio base station and the secondary radio terminal will be described with the secondary radio base station 24 and the secondary radio terminal 2b shown in FIG. 8 as representative configurations.
When the primary radio base station 1 receives the interference information packet transmitted from the primary radio terminal 1a, the primary radio base station 1 sends an identifier request signal for requesting the identifier of the secondary radio base station that is causing interference to the management station 3 via the signal line. (Step S10). That is, in the primary radio base station 1, the base station-terminal interface unit 14 analyzes the interference information packet and outputs the analysis result to the inter-base station interface unit 15 as interference information. Then, when the inter-base station interface unit 15 reads the interference information, the identifier request signal for requesting the identifier of the secondary radio base station giving interference, the identifier of the own radio base station (primary radio base station 1), and The frequency information used by the own radio base station is output to the management station 3 via the signal line.

Based on the identifier and frequency information output from the primary radio base station 1, the management station 3 is a secondary radio base station that is interfering with the radio base station (primary radio base station 1) of the identifier, that is, the same frequency. Among the secondary radio base stations using the wireless base stations, the secondary radio base stations having non-interference areas are investigated (detected) (step S11).
Then, the management station 3 outputs the identifier of the corresponding secondary radio base station 24 to the primary radio base station 1 via the signal line (step S12).

The primary radio base station 1 outputs interference information to the secondary radio base station 24 having the identifier output from the management station 3 (step S13).
That is, when the identifier output from the management station 3 is input, the inter-base station interface unit 15 outputs interference information to the secondary radio base station 24 having the identifier via the signal line.
This interference information includes information on the frequency band that the primary radio base station 1 is using.
Then, the secondary radio base station 24 determines whether the frequency band being used overlaps with the frequency band used by the primary radio base station 1. If the secondary radio base station 24 determines that the frequency bands overlap, the secondary radio base station 24 transmits an operation stop packet to all secondary radio terminals existing in the service area of the own radio base station (secondary radio base station 24). (Step S14), the operation of the own radio base station is stopped.

That is, when the interference information output from the primary radio base station 1 is input, the inter-base station interface unit 215 outputs an operation stop control instruction to the radio signal processing unit 212 and also the base station-terminal interface unit 214. Operation stop instruction is output to. When reading the operation stop instruction, the base station-terminal interface unit 214 generates an operation stop packet and outputs the operation stop packet to the radio signal processing unit 212 via the switch 213. When the radio signal processing unit 212 reads the operation stop control instruction output from the inter-base station interface unit 215 and reads the operation stop packet output from the base station-terminal interface unit 214, the radio signal processing unit 212 wirelessly transmits the operation stop packet. As a signal, it is transmitted to the secondary wireless terminal 2b, and the communication process is stopped.
If the secondary radio base station 24 determines that the frequency bands do not overlap, the secondary radio base station 24 outputs the determination result to the primary radio base station 1.

  When the secondary wireless terminal 2b receives the operation stop packet transmitted from the secondary wireless base station 24, the secondary wireless terminal 2b stops the operation of the own wireless terminal (secondary wireless terminal 2b) (step S15). That is, the base station-terminal interface unit 2a3 analyzes the operation stop packet transmitted from the secondary radio base station 24 and outputs an operation stop control instruction to the radio signal processing unit 2a2. When the wireless signal processing unit 2a2 reads the operation stop control instruction, the wireless signal processing unit 2a2 stops the communication process.

An outline of operations of these wireless communication systems 100 will be briefly described.
In FIG. 1, the primary radio base station 1 and the secondary radio base stations 21, 22, and 23 are in operation, and the secondary radio base station 24 is not in operation. In FIG. 1, no interference occurs between the service areas of the respective radio base stations.
In such a state, when the secondary radio base station 24 starts operation, as shown in FIG. 8, a portion that overlaps the non-interference area of the secondary radio base station 24 and the non-interference area of the primary radio base station 1 occurs. Suppose. The primary radio terminal 1a existing in the service area where the non-interference areas of the secondary radio base station 24 overlap is interfered with by radio waves transmitted from the secondary radio base station 24 or the secondary radio terminal 2b existing in the service area. Will receive.

As described above, the primary wireless terminal 1a periodically performs the interference detection process. For example, when the reception level observed by the interference detection process is −95 dBm, the primary radio terminal 1a determines that it has received interference from any secondary radio base station or secondary radio terminal. Then, the primary radio terminal 1 a transmits an interference information packet to the primary radio base station 1.
When receiving the interference information packet, the primary radio base station 1 inquires of the management station 3 about the identifier of the secondary radio base station that interferes with the primary radio terminal 1a existing in the service area of the own radio base station.

The management station 3 investigates (detects) the secondary radio base station that interferes with the primary radio base station 1 based on the location of the managed radio base station and the non-interference area range information. Since the non-interference area of the secondary radio base station 24 overlaps the non-interference area of the primary radio base station 1, the management station 3 transmits the identifier of the secondary radio base station 24 to the primary radio base station 1.
The primary radio base station 1 identifies the corresponding secondary radio base station 24 from the identifier, and outputs interference information to the secondary radio base station 24.

The secondary radio base station 24 transmits an operation stop packet to all the secondary radio terminals existing in the service area of the own radio base station, and stops the operation of the own radio base station.
Then, the secondary wireless terminal 2b receives the operation stop packet and stops the operation of the own wireless terminal.

As described above, according to the wireless communication system 100 in the present embodiment, it is not necessary to determine whether or not the frequency can be used from various information as in the conventional centralized control, and the secondary system as in the conventional distributed control. Since it is detected whether or not there is interference in the primary system without determining whether or not the frequency can be used, it is possible to easily and reliably prevent interference from the secondary system to the primary system. .
Therefore, the communication quality of the primary system can be improved.

In the present embodiment, the interference detection process is performed in the primary radio terminal 1a. However, the present invention is not limited to this, and the process may be performed in the primary radio base station 1.
Although the interference detection process in the present embodiment is periodic, the present invention is not limited to this, and the interference detection process may be performed intermittently, such as performing an interference detection process between normal application communications.
Further, although interference detection processing based on the reception level has been shown, interference may be detected using error rate, throughput information, received signal spectrum, received signal periodicity, and the like. In the interference detection process, the plurality of pieces of information may be used simultaneously.

In the present embodiment, the management station 3 manages the range information of the non-interference area. However, the present invention is not limited to this. For example, instead of the range information of the non-interference area, the location and transmission of the radio base station The same processing as in the present embodiment can also be performed by managing information on the range of power and service area.
In the present embodiment, the management station 3 specifies the secondary radio base station that gives interference. However, the present invention is not limited to this. For example, the primary radio base station 1 itself transmits each radio from the management station 3. The same processing as in this embodiment is also possible by acquiring the location (position) of the base station and the range information of the non-interference area and specifying the secondary radio base station that is causing interference. In this case, the inter-base station interface unit 15 (interference station specifying means) can specify the secondary radio base station that is causing interference.

As a similar idea, after the management station 3 identifies a secondary radio base station that is causing interference, the management station 3 itself may transmit an operation stop to the secondary radio base station.
Further, even if the management station 3 is not installed, all radio base stations exchange non-interference area range information, and each radio base station manages the location of all radio base stations and non-interference area range information, The primary radio base station 1 itself can specify the secondary radio base station that is causing interference to perform the same processing as in the present embodiment. In this case, the inter-base station interface unit 15 (interference station specifying means) can specify the secondary radio base station that is causing interference.

  Further, in the present embodiment, when interference occurs, the operation of the secondary radio base station that gives interference is stopped. However, the present invention is not limited to this, and the frequency band (communication frequency), communication method, and modulation method to be used are not limited thereto. Further, at least one of transmission power, antenna directivity, and polarization may be changed.

  In this embodiment, the terms primary radio base station, primary radio terminal, secondary radio base station, and secondary radio terminal are used, but the primary radio base station and primary radio terminal are the secondary radio base station and secondary radio terminal. It is used in the sense that the priority of operation is higher than that. That is, in order to prioritize the operation of the primary radio base station and the primary radio terminal, the operation of the secondary radio base station and the secondary radio terminal is stopped. As a classification of “primary” and “secondary”, for example, “radio base station that started operation first” is primary and “radio base station that started operation later” is secondary. In some cases, the “radio base station having a license for the license” is the primary and the “radio base station having no license” is the secondary.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.
9 to 13 show a second embodiment of the present invention.
This embodiment and the first embodiment have the same basic configuration, and different points will be mainly described here.
The configuration of the wireless communication system in the present embodiment is the same as that shown in FIG.
Further, all radio base stations transmit radio waves at the same transmission power level, and the service areas and non-interference areas of all radio base stations are the same.
Furthermore, the management station 3 manages the identifier, position information, and usage frequency band of each radio base station. These pieces of information are transmitted to the management station 3 when the operation of the radio base station is newly started or periodically.

FIG. 9 is a block diagram showing the primary wireless terminal 1aa of the present embodiment.
The primary radio terminal 1aa includes an error rate measurement unit (interference detection means) 1a7.
The error rate measuring unit 1a7 measures an error rate (for example, a bit error rate or a packet error rate) in communication application communication from the received signal output from the radio signal processing unit 1a6. Then, the error rate measurement unit 1a7 outputs the measurement result to the base station-terminal interface unit 1a4.
The base station-terminal interface unit 1a4 generates an interference information packet based on the comparison result of the reception level and the measurement result such as the error rate, and this interference information packet is subjected to radio signal processing via the switch 1a5. To the unit 1a6.
The configuration of the primary radio base station in the present embodiment is the same as that of the primary radio base station 1 in the first embodiment.

FIG. 10 is a block diagram showing the secondary radio base station 21A.
When the interference information output from the primary radio base station 1 is input, the inter-base station interface unit 215 performs frequency change control (outputs a frequency change control instruction) to the radio signal processing unit 212, and A frequency change instruction is output to the station-terminal interface unit 214. When reading the frequency change instruction, the base station-terminal interface unit 214 generates a frequency change packet and outputs the frequency change packet to the radio signal processing unit 212 via the switch 213. When the radio signal processing unit 212 reads the frequency change control instruction output from the inter-base station interface unit 215 and reads the frequency change packet output from the base station-terminal interface unit 214, the radio signal processing unit 212 wirelessly transmits the frequency change packet. As a signal, it is transmitted to the secondary wireless terminal 2aa, and the currently used frequency is changed.

FIG. 11 is a block diagram showing the secondary wireless terminal 2aa.
The packet identification unit 2a4 identifies whether the packet output from the wireless signal processing unit 2a2 is an application communication packet or a frequency change packet. If the packet is a frequency change packet, the packet identification unit 2a4 connects the base point and the connection point A, and outputs the frequency change packet to the base station-terminal interface unit 2a3. The base station-terminal interface unit 2a3 analyzes the frequency change packet and outputs a frequency change control instruction to the radio signal processing unit 2a2. When the radio signal processing unit 2a2 reads the frequency change control instruction, the radio signal processing unit 2a2 changes the currently used frequency to a frequency included in the frequency change control instruction.

Next, the operation of the wireless communication system according to this embodiment configured as described above will be described.
Here, operations different from those of the first embodiment will be mainly described.
FIG. 12 is a flowchart showing the processing of the primary wireless terminal 1aa.
The interference detection process in the present embodiment is performed during application communication.
If the primary radio terminal 1aa determines that the timer has expired (step S2; YES), the primary radio terminal 1aa observes the reception level and measures the error rate in normal application communication (step S20). That is, the error rate measurement unit 1a7 measures the PER (packet error rate) from the received signal and outputs the measurement result to the base station-terminal interface unit 1a4. The PER can be measured, for example, by adding a parity check bit to a packet of application communication data before transmission and performing a parity check at the time of reception. The base station-terminal interface unit 1a4 generates an interference information packet when it is determined that the reception level exceeds the preset threshold value and the PER also exceeds the preset threshold value (steps S21 and S22). The interference information packet is output to the radio signal processing unit 1a6 via the switch 1a5.

  In the present embodiment, for example, the reception level threshold is set to -80 dBm, and the PER threshold is set to 0.2. Therefore, when the reception level observed by the interference detection process is −75 dBm and the measured PER is 0.25, it is determined that interference is received from any secondary radio base station or secondary radio terminal.

Next, processing for changing the frequency of the secondary radio base station that is causing interference to the primary radio terminal (frequency change processing) will be described.
Here, operations different from those of the first embodiment will be mainly described.
FIG. 13 is a flowchart showing frequency change processing of the wireless communication system.
Based on the identifier and frequency information output from the primary radio base station 1, the management station 3 investigates (detects) the secondary radio base station that interferes with the radio base station (primary radio base station 1) with that identifier. (Step S11). In the present embodiment, in the management station 3, the secondary radio base station 24 existing closest to the primary radio base station 1 with the identifier among the secondary radio base stations using the same frequency gives interference. The identifier of the secondary radio base station 24 is output to the primary radio base station 1.

Further, when the interference information output from the primary radio base station 1 is input to the secondary radio base station 24, the frequency band being used has the same frequency band as the frequency band used by the primary radio base station 1. Determine if you are using it.
If the secondary radio base station 24 determines that the same frequency band is used, the frequency change packet is transmitted to all secondary radio terminals existing in the service area of the own radio base station (secondary radio base station 24). Is transmitted (step S30), and the frequency used in the own radio base station is changed. The frequency change packet includes frequency information of the change destination of the secondary radio base station 24.

  That is, when the interference information output from the primary radio base station 1 is input, the inter-base station interface unit 215 outputs a frequency change control instruction to the radio signal processing unit 212 and also the base station-terminal interface unit 214. Output frequency change instruction to. When reading the frequency change instruction, the base station-terminal interface unit 214 generates a frequency change packet and outputs the frequency change packet to the radio signal processing unit 212 via the switch 213. When the radio signal processing unit 212 reads the frequency change control instruction output from the inter-base station interface unit 215 and reads the frequency change packet output from the base station-terminal interface unit 214, the radio signal processing unit 212 wirelessly transmits the frequency change packet. As a signal, it is transmitted to the secondary wireless terminal 2b and the operating frequency is changed.

  When the secondary radio terminal 2b receives the operation stop packet transmitted from the secondary radio base station 24, the secondary radio terminal 2b changes the frequency operated in the own radio terminal (secondary radio terminal 2b) (step S31). That is, the base station-terminal interface unit 2a3 analyzes the frequency change packet transmitted from the secondary radio base station 24 and outputs a frequency change control instruction to the radio signal processing unit 2a2. When the radio signal processing unit 2a2 reads the frequency change control instruction, the radio signal processing unit 2a2 changes the used frequency to a frequency included in the frequency change control instruction.

  Even after the frequency change, if interference is detected by the interference detection process of the primary radio terminal, it is determined that another secondary radio base station or radio terminal is interfering with the primary radio terminal, and the primary radio base station Requests the management station for an identifier of another secondary radio base station candidate that is likely to cause interference. The management station uses the identifier of the secondary radio base station that is closest to the radio base station of that identifier among the radio base stations that are using the same frequency band, excluding the secondary radio base station determined earlier as the primary. Reply to the radio base station. Thereafter, such a process is repeated until no interference is detected.

  As mentioned above, according to the radio | wireless communications system in this embodiment, generation | occurrence | production of the interference from a secondary system to a primary system can be prevented easily and reliably, and the communication quality of a primary system can be improved.

In the present embodiment, the interference detection process is performed in the primary radio terminal 1aa. However, the present invention is not limited to this, and the process may be performed in the primary radio base station.
Moreover, although the interference detection process in this embodiment was made periodic, it is not restricted to this, You may perform regularly during normal application communication.
Further, although the interference detection process based on the reception level and the packet error rate is shown, the interference detection process may be performed using the throughput information, the spectrum of the reception signal, the periodicity of the reception signal, and the like. In the interference detection process, the plurality of pieces of information may be used simultaneously.

In the present embodiment, the management station 3 specifies the secondary radio base station 24 that has a high possibility of causing interference. However, the present invention is not limited to this. For example, the primary radio base station 1 itself manages the management station 3. The processing similar to that of the present embodiment can also be performed by acquiring the location information of each radio base station from the above and identifying a secondary radio base station that is highly likely to cause interference.
As a similar idea, after the management station 3 identifies a secondary radio base station that is likely to be causing interference, the management station 3 itself may output a frequency change instruction to the secondary radio base station. .
Even if the management station 3 is not installed, all the radio base stations exchange position information, and each radio base station manages the position information of all the radio base stations, so that the primary radio base station 1 itself causes interference. By specifying a secondary radio base station that is highly likely to be given, processing similar to that of the present embodiment can be performed.

In the present embodiment, the management station 3 determines that there is a high possibility that the secondary radio base station 24 existing in the place closest to the primary radio base station 1 is causing interference, but in reality, the propagation station or the base station Depends on the transmission power. For example, when the transmission power of a certain radio base station is large, the service area and the non-interference area also become large. Therefore, even if the position of the radio base station is far from the primary radio base station 1, The possibility of giving interference to the station 1 is high. Therefore, it is necessary to consider this information.
In this embodiment, the secondary radio base station that has a high possibility of causing interference changes the frequency, but this is not a limitation, and operation stop control, communication method, modulation method, transmission power, or antenna At least one of directivity and polarization may be changed.

(Embodiment 3)
Next, a third embodiment of the present invention will be described.
14 to 20 show a third embodiment of the present invention.
This embodiment and the first embodiment have the same basic configuration, and different points will be mainly described here.
FIG. 14 shows a configuration diagram of a wireless communication system 100a in the present embodiment.
In the wireless communication system 100a in the present embodiment, the management station 3 in the first embodiment is not installed.

FIG. 15 is a block diagram showing the primary radio base station 1B.
When the interference information output from the base station-terminal interface unit 14 is input, the inter-base station interface unit 15 outputs the interference information to all the secondary radio base stations 21B, 22B, 23B, and 24B.

FIG. 16 is a block diagram showing the secondary radio base station 21B.
The inter-base station interface unit 215 receives the interference information output from the primary radio base station 1B, and determines whether or not the transmission power should be changed based on the interference information. If the inter-base station interface unit 215 determines that the transmission power should be changed, it performs transmission power change control (outputs a transmission power change control instruction) to the radio signal processing unit 212, and the base station-terminal. A transmission power change instruction is output to the inter-interface section 214. When reading the transmission power change instruction, the base station-terminal interface unit 214 generates a transmission power change packet, and outputs the transmission power change packet to the radio signal processing unit 212 via the switch 213. When the radio signal processing unit 212 reads the transmission power change control instruction output from the inter-base station interface unit 215 and reads the transmission power change packet output from the base station-terminal interface unit 214, the radio signal processing unit 212 changes the transmission power. The packet is transmitted as a radio signal to the secondary radio terminal 2ab, and the currently used transmission power is changed.

FIG. 17 is a block diagram showing the secondary wireless terminal 2ab.
The packet identification unit 2a4 identifies whether the packet output from the wireless signal processing unit 2a2 is an application communication packet or a transmission power change packet. When the packet is a transmission power change packet, the packet identification unit 2a4 connects the base point and the connection point A, and outputs the transmission power change packet to the base station-terminal interface unit 2a3. The base station-terminal interface unit 2a3 analyzes the transmission power change packet and outputs a transmission power change control instruction to the radio signal processing unit 2a2. When the wireless signal processing unit 2a2 reads the transmission power change control instruction, the wireless signal processing unit 2a2 changes the currently used transmission power to the transmission power included in the transmission power change control instruction.

Next, a process (transmission power changing process) for changing the transmission power of the secondary radio base station that interferes with the primary radio terminal will be described.
Here, operations different from those of the first embodiment will be mainly described.
FIG. 18 is a flowchart showing transmission power change processing of the wireless communication system 100a.
The primary radio base station 1B receives the interference information packet transmitted from the primary radio terminal 1a, and outputs the interference information to all the secondary radio base stations 21B, 22B, 23B, 24B (step S40). The interference information packet includes a difference value between the threshold value and the reception level (a reception level value that exceeds the threshold value).
Specifically, the base station-terminal interface unit 14 analyzes the interference information packet and outputs the analysis result to the base station interface unit 15 as interference information. The interference information includes the position of the primary radio base station 1B, the frequency band being used, the radius of the non-interference area, and the reception level value that exceeds the threshold at the primary radio terminal.
Further, the inter-base station interface unit 15 outputs the interference information to all the secondary radio base stations 21B, 22B, 23B, and 24B.

  The secondary radio base station analyzes the interference information, and determines whether the secondary radio base station using the same frequency band as the primary radio base station 1B is giving interference to the primary radio base station 1B ( Step S41). That is, the secondary radio base station determines whether the position of the primary radio base station 1B and the radius of the non-interference area overlap with the non-interference area of the own radio base station. Then, if they overlap, the secondary radio base station determines whether or not the transmission power should be reduced (step S42). Furthermore, if the secondary radio base station determines that the transmission power should not be reduced, the process ends. On the other hand, when the secondary radio base station determines that the transmission power should be reduced, the secondary radio base station transmits a transmission power change packet to the secondary radio terminal in the service area (step S43), and lowers the used transmission power by the same value. .

The transmission power change packet includes the transmission power level to be changed (the difference between the threshold value and the reception level).
The secondary wireless terminal that has received the transmission power change packet immediately changes the transmission power (step S44).

An outline of the operation of these wireless communication systems 100a will be briefly described.
FIG. 19 shows the distance between radio base stations. The non-interference area of the radio base station is a circle with a radius of 400 m.
At this time, when the secondary radio base station 24B starts operation, a non-interference area of the secondary radio base station 24B overlaps with a non-interference area of the primary radio base station 1B as shown in FIG. The primary radio terminal 1a existing in the service area where the non-interference areas of the secondary radio base station 24B overlap is interfered by radio waves transmitted from the secondary radio base station 24B or the secondary radio terminal 2b existing in the service area. Will receive.

  The primary radio terminal 1a periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −95 dBm, it is determined that interference is received from any secondary radio base station or secondary radio terminal. At this time, an interference information packet is transmitted from the primary radio terminal 1a to the primary radio base station 1B. The interference information packet includes a reception level value of 5 dBm that exceeds the threshold.

When the primary radio base station 1B receives the interference information packet, the primary radio base station 1B outputs the interference information to all the secondary radio base stations 21B, 22B, 23B, and 24B.
All secondary radio base stations 21B, 22B, 23B, and 24B to which interference information is input investigate whether the position of the primary radio base station 1B and the radius of the non-interference area overlap with the non-interference area of the own radio base station. To do. When the distance between the primary radio base station 1B and the secondary radio base station is smaller than the total radius of the non-interference areas of the primary radio base station 1B and the secondary radio base station, the non-interference areas overlap. Since the secondary radio base station 24B corresponds to this, the secondary radio base station 24B transmits a transmission power change packet to all the secondary radio terminals existing in the service area of the own radio base station, and the transmission power of the own radio base station. Reduce by 5 dBm.
Similarly, the secondary wireless terminal that has received the transmission power change packet lowers the transmission power by 5 dBm.
If interference is detected by the interference detection process of the primary radio terminal even after the secondary radio base station and the secondary radio terminal reduce the transmission power, the transmission power of the secondary radio base station and the secondary radio terminal is further reduced. Therefore, the primary radio base station adds a larger reception level value (for example, 10 dBm) to the interference information packet and transmits it to the secondary radio base station. Hereinafter, the radio communication system 100a repeats such processing until no interference is detected.

  As described above, according to the wireless communication system 100a in the present embodiment, it is possible to easily and reliably prevent the interference from the secondary system to the primary system, and to improve the communication quality of the primary system.

In the present embodiment, the interference detection process is performed in the primary radio terminal 1a. However, the present invention is not limited to this, and the process may be performed in the primary radio base station 1B.
Although the interference detection process in the present embodiment is periodic, the present invention is not limited to this, and the interference detection process may be performed intermittently, such as performing an interference detection process between normal application communications.
Further, although the interference detection processing based on the reception level is shown, the error rate, throughput, spectrum of the received signal, and periodicity information of the received signal may be used. In the interference detection process, the plurality of pieces of information may be used simultaneously.

In the present embodiment, the secondary radio base station determines whether or not the primary radio base station 1B is interfering. However, the present invention is not limited to this, and the distance information is included in the interference information output from the primary radio base station 1B. In addition, the secondary radio base station existing within a certain distance from the primary radio base station 1B may always perform a process of changing the transmission power.
Further, in the present embodiment, the radius of the non-interference area is included in the interference information, but this is not a limitation. For example, instead of the radius of the non-interference area, the transmission power level of the radio base station and the range of the service area With this information, the same processing as in the present embodiment is possible.
Further, in the present embodiment, the transmission power of the secondary radio base station giving interference is changed. However, this is not limited to this, and the frequency, communication method, modulation method, antenna directivity, polarization change may be changed. It may be an operation stop control.
In the present embodiment, the primary radio base station 1B outputs interference information to all secondary radio base stations. However, the present invention is not limited to this, and the primary radio base station 1B includes its own radio base station and all secondary radio base stations. Information related to the base station (for example, information held by the management station 3) is stored, and the base station interface unit (interference station specifying means) 15 specifies the secondary wireless communication station 24 that is the cause of interference from the information. Then, the interference information may be output to the secondary radio base station 24.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described.
21 to 24 show a fourth embodiment of the present invention.
The basic configuration of this embodiment is the same as that of the third embodiment, and here, different points will be mainly described.
FIG. 21 is a block diagram showing the primary radio terminal 1ac.
The primary radio terminal 1ac includes a throughput measurement unit (interference detection unit) 1a8.
The throughput measuring unit 1a8 measures the throughput in normal application communication from the received signal output from the radio signal processing unit 1a6, and outputs the measurement result to the base station-terminal interface unit 1a4.
The base station-terminal interface unit 1a4 generates an interference information packet based on a reception level comparison result and a measurement result such as throughput, and the interference information packet is transmitted to the radio signal processing unit via the switch 1a5. Output to 1a6.

FIG. 22 is a block diagram showing the primary radio base station 1C.
The primary radio base station 1 </ b> C includes a database 16 connected to the inter-base station interface unit 15.
The database 16 stores location information of all radio base stations.

Next, the operation of the wireless communication system according to this embodiment configured as described above will be described.
Here, operations different from those of the first embodiment will be mainly described.
The primary radio base station 1C and the secondary radio base stations 21, 22, 23, and 24 regularly exchange location information using signal lines or networks, and manage the location information of all radio stations in their respective databases. Yes.
FIG. 23 is a flowchart showing processing of the primary wireless terminal 1ac.
When the primary wireless terminal 1ac determines that the timer has expired (step S2; YES), the primary wireless terminal 1ac observes the reception level and measures the throughput in normal application communication (step S50). Then, the primary wireless terminal 1ac compares the reception level with the threshold value, and further compares the throughput with the threshold value (step S51).

When the primary radio terminal 1ac determines that the reception level exceeds the threshold and the throughput is below the threshold (step S52; YES), the primary radio terminal 1ac transmits an interference information packet to the primary radio base station 1C (step S7). The process ends.
In this embodiment, the reception level threshold is set to -80 dBm, and the throughput threshold is set to 6 Mbit / s.
On the other hand, if the primary wireless terminal 1ac determines that the reception level does not exceed the threshold and the throughput does not fall below the threshold (step S52; NO), the process ends.

Next, a process (operation stop process) for stopping the operation of the secondary radio base station that interferes with the primary radio terminal will be described.
FIG. 24 is a flowchart showing operation stop processing of the wireless communication system.
When receiving the interference information packet transmitted from the primary radio terminal 1ac, the primary radio base station 1C outputs the interference information to the secondary radio base station existing within a certain distance. That is, the base station-terminal interface unit 14 analyzes the interference information packet and then outputs the interference information to the base station interface unit. The inter-base station interface unit 15 reads the position information from the database 16 (step S60), and acquires the position information of the secondary radio base station existing within a certain distance. Then, the interference information is transmitted to the secondary radio base station corresponding to the position information (step S61). In this interference information, information on the frequency band being used by the primary radio base station is stored.

  When the interference information is input, the secondary radio base station determines whether the same frequency band as the frequency used by the primary radio base station 1C is used. If the secondary radio base station determines that the same frequency band is used, the secondary radio base station transmits an operation stop packet to all the secondary radio terminals existing in the service area (step S62), and stops the operation. To do. The secondary wireless terminal that has received the operation stop packet immediately stops operation (step S63).

  If interference is detected by the interference detection process of the primary radio terminal 1ac even after the operation of the secondary radio base station and the secondary radio terminal is stopped, the secondary radio base station and the secondary radio terminal are separated from the stopped operation. Since the secondary radio base station or the secondary radio terminal is considered to be interfering with the primary radio terminal 1ac, the primary radio base station 1C sends interference information to the secondary radio base station existing within a larger distance. Output. Hereinafter, the wireless communication system repeats such processing until no interference is detected.

An outline of operations of these wireless communication systems will be briefly described.
The primary radio terminal 1ac periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −75 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any secondary radio base station or secondary radio terminal. Then, the primary radio terminal 1ac transmits an interference information packet to the primary radio base station 1C.
When receiving the interference information packet, the primary radio base station 1C refers to the database and acquires information on the secondary radio base station existing within 700 m from the own radio base station. Then, the primary radio base station 1C outputs interference information to the corresponding secondary radio base station.

When the interference information is input, the secondary radio base station transmits an operation stop packet to all the secondary radio terminals existing in the service area of the own radio base station, and stops the operation of the own radio base station.
The secondary wireless terminal that has received the operation stop packet stops operation.
Even if a secondary radio base station does not interfere with the primary radio base station 1C, even after the secondary radio base station stops operating, interference is detected by the interference detection process of the primary radio terminal 1ac. In this case, for example, the operation of the secondary radio base station existing within 1000 m is stopped. Then, in the primary radio terminal, the range of secondary radio base stations whose operation is stopped is expanded until no interference is detected.

  As mentioned above, according to the radio | wireless communications system in this embodiment, generation | occurrence | production of the interference from a secondary system to a primary system can be prevented easily and reliably, and the communication quality of a primary system can be improved.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described.
The basic configuration of this embodiment is the same as that of the fourth embodiment, and only the differences will be described here.
The configuration of the wireless communication system in the present embodiment is the same as the configuration shown in FIG.
The primary radio terminal 1a performs processing (interference detection processing) for detecting interference received from the secondary radio base station or the secondary radio terminal in addition to normal application communication. In this embodiment, the reception level threshold is set to -80 dBm, and the throughput threshold is set to 6 Mbit / s. When interference is detected, the primary radio terminal 1a transmits an interference information packet to the primary radio base station.

  When the primary radio base station 1 receives the interference information packet output from the primary radio terminal 1a, the primary radio base station 1 outputs the interference information to all the secondary radio base stations. This interference information includes the position of the primary radio base station 1, the operation stop range, and the frequency being used. The secondary radio base station to which the interference information is input determines whether the same frequency band as that used by the primary radio base station 1 is used. When the secondary radio base station determines that the own radio base station uses the same frequency band as the primary radio base station 1 and is within the operation stop range centering on the position of the primary radio base station 1 In this case, the operation stop packet is transmitted to all secondary wireless terminals existing in the service area, and the operation is stopped. The secondary wireless terminal that has received the operation stop packet immediately stops operation. The flowchart of the operation stop process of this embodiment is the same as that of FIG.

  Even after the operation is stopped, when interference is detected by the interference detection process of the primary wireless terminal 1a, the secondary wireless base station or secondary wireless terminal different from the stopped secondary wireless base station and the secondary wireless terminal The primary radio base station 1 determines that interference is given to the radio terminal 1a, and increases the operation stop range and outputs interference information to all the secondary radio base stations. Hereinafter, the wireless communication system repeats such processing until no interference is detected.

An outline of operations of these wireless communication systems will be briefly described.
The primary radio terminal 1a existing in the service area where the non-interference areas of the secondary radio base station overlap is subject to interference by radio waves transmitted from the secondary radio base station or the secondary radio terminal existing in the service area. Become.
The primary radio terminal 1a periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −75 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any secondary radio base station or secondary radio terminal. The Therefore, the primary radio terminal 1 a transmits an interference information packet to the primary radio base station 1.

When receiving the interference information packet, the primary radio base station 1 outputs the interference information to the secondary radio base station. This interference information includes information that sets the operation stop range to 700 m or less. Since the secondary radio base station to which the interference information is input exists within 700 m from the primary radio base station 1, the secondary radio base station sends an operation stop packet to all secondary radio terminals existing in the service area of the own radio base station. Transmit and stop operation of own radio base station.
Similarly, the secondary wireless terminal that has received the operation stop packet stops operation.
If interference is detected by the interference detection process of the primary radio terminal 1a even after the operation of the secondary radio base station and the secondary radio terminal is stopped, the secondary radio base station and the secondary radio terminal are separated from the stopped operation. Since the secondary radio base station or the secondary radio terminal is considered to be interfering with the primary radio terminal 1a, the primary radio base station 1 is located at a secondary radio base existing within a larger distance (for example, within 1000 m). Output interference information to the station. Hereinafter, the wireless communication system repeats such processing until no interference is detected.

  As mentioned above, according to the radio | wireless communications system in this embodiment, generation | occurrence | production of the interference from a secondary system to a primary system can be prevented easily and reliably, and the communication quality of a primary system can be improved.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described.
25 to 26 show a sixth embodiment of the present invention.
The basic configuration of this embodiment is the same as that of the fourth embodiment, and only the differences will be described here.

FIG. 25 shows a configuration of a wireless communication system 100D in the present embodiment.
The primary wireless terminal 1ad performs processing (interference detection processing) for detecting interference received from the secondary wireless base stations 21D to 30D or the secondary wireless terminal in addition to normal application communication. In the present embodiment, the reception level threshold is set to -80 dBm, and the throughput threshold is set to 6 Mbit / s. When the interference is detected, the primary radio terminal 1ad transmits an interference information packet to the primary radio base station 1D.

Next, a process (operation stop process) for stopping the operation of the secondary radio base station that interferes with the primary radio terminal will be described.
FIG. 26 is a flowchart showing operation stop processing of the wireless communication system 100D.
When the primary radio base station 1D receives the interference information packet output from the primary radio terminal 1ad, the primary radio base station 1D outputs interference information to all secondary radio base stations (adjacent secondary radio base stations) connected by the signal line ( Step S70). This interference information includes the number of operation stop hops (number of interference avoidance hops) and the frequency band being used. The secondary radio base station that has received the interference information analyzes the interference information and determines whether the number of operation stop hops is 2 or more (step S71). If the secondary radio base station determines that the number of operation stop hops is 2 or more (step S71: YES), the number of operation stop hops is reduced by one and is adjacent (connected by a signal line). Interference information is output to all secondary radio base stations (step S72).
Note that the number of operation stop hops indicates the range of the radio base station that instructs operation stop.
On the other hand, if the secondary radio base station determines that the number of operation stop hops is 1 or less (step S71; NO), it does not output interference information to other secondary radio base stations.

Then, the secondary radio base station determines whether the same frequency band as that used by the primary radio base station 1D is used. When determining that the secondary radio base station uses the same frequency band, the secondary radio base station transmits an operation stop packet to all the secondary radio terminals existing in the service area via the base station-terminal interface (step S62). , Stop operation. The secondary wireless terminal that has received the operation stop packet immediately stops operation (step S63).
If interference is detected by the interference detection process of the primary radio terminal 1ad even after the secondary radio base station and the secondary radio terminal stop operating, the secondary radio base station and the secondary radio terminal are separated from the stopped secondary radio base station and secondary radio terminal. Since the secondary radio base station or the secondary radio terminal is considered to be interfering with the primary radio terminal 1ad, the primary radio base station 1D further increases the number of operation stop hops and interferes with the adjacent secondary radio base station. Output information. Hereinafter, the radio communication system 100D repeats such a process until no interference is detected.

An outline of the operation of these wireless communication systems 100D will be briefly described.
The primary radio terminal 1ad periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −75 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any secondary radio base station or secondary radio terminal. . Therefore, the primary radio terminal 1ad transmits an interference information packet to the primary radio base station 1D.
When receiving the interference information packet, the primary radio base station 1D outputs the interference information to the secondary radio base station. This interference information includes information in which the number of operation stop hops is 1. The secondary radio base station to which the interference information is input transmits an operation stop packet to all the secondary radio terminals existing in the service area of the own radio base station, and stops the operation of the own radio base station.
Similarly, the secondary wireless terminal that has received the operation stop packet stops operation.
When interference is detected by the interference detection process of the primary radio terminal 1ad, the primary radio base station 1D further sets the operation stop hop count to 2 and outputs interference information to the adjacent secondary radio base station. Hereinafter, the radio communication system 100D repeats such a process until no interference is detected.

  As described above, according to the wireless communication system 100D in the present embodiment, it is possible to easily and reliably prevent interference from the secondary system to the primary system, and to improve the communication quality of the primary system.

  In addition, although the number of operation stop hops is shown as the number of interference avoidance hops, the present invention is not limited to this. Of the communication frequency, communication method, modulation method, transmission power, antenna directivity, and polarization of the secondary wireless communication station The number of hops may be set as an instruction to change at least one of the above.

(Embodiment 7)
Next, a seventh embodiment of the present invention will be described.
27 to 32 show a seventh embodiment of the present invention.
The basic configuration of this embodiment is the same as that of the fourth embodiment, and only the differences will be described here.

FIG. 27 shows a system configuration of a wireless communication system 100E in the present embodiment.
In the radio communication system 100E, ad hoc radio communication is assumed, and the secondary radio terminals 2ae and 2be communicate with each other. Similarly, the secondary radio terminals 2ce and 2de and the secondary radio terminals 2ee and 2fe We are communicating. Further, the primary radio base station 1 and the secondary radio base station communicate with each other by a CDMA (Code Division Multiple Access) communication method.
All the secondary wireless terminals 2ae to 2fe are assumed to use the same frequency band for application communication. As long as the non-interference areas do not overlap, no interference occurs in communication with each other. Moreover, all the secondary radio | wireless terminals 2a-2f can utilize the frequency different from the frequency for communication for transmission / reception of an interference information packet.

FIG. 28 is a block diagram showing the secondary wireless terminals 2ae to 2fe in the present embodiment.
The packet identification unit 2a4 identifies whether the packet output from the wireless signal processing unit 2a2 is an application communication packet or an interference information packet. When the packet is an interference information packet, the packet identification unit 2a4 connects the base point and the connection point A, and outputs the interference information packet to the base station-terminal interface unit 2a3. The base station-terminal interface unit 2a3 analyzes the interference information packet and outputs a spread code change packet and a spread code change instruction to the radio signal processing unit 2a2. The wireless signal processing unit 2a2 transmits the spreading code change packet to the opposing secondary wireless terminal, and changes the currently used spreading code to the spreading code included in the spreading code change instruction.

Next, the operation of the radio communication system 100E according to this embodiment configured as described above will be described.
FIG. 29 is a flowchart showing the operation of the primary wireless terminal 1ae.
Here, operations different from those in the fourth embodiment will be mainly described.
When the primary radio terminal 1ae determines that the reception level exceeds the threshold and the throughput is below the threshold (step S52; YES), the primary radio terminal 1ae transmits an interference information packet to the secondary radio base station (step S80) and performs processing. Exit. The transmission of the interference information packet is radiated from the antenna in all directions with a certain fixed transmission power by using the transmission / reception frequency of the interference information packet. This interference information packet includes information on the frequency and spreading code used by the primary radio terminal 1ae.

Next, processing for changing the spreading code of the secondary radio terminal that is interfering with the primary radio terminal 1ae (spreading code changing processing) is performed.
FIG. 30 is a flowchart showing processing of the secondary wireless terminal.
When the secondary radio terminal receives the interference information packet transmitted from the primary radio terminal 1ae, the base station-terminal interface unit 2a3 analyzes the interference information packet. When the base station-terminal interface unit 2a3 uses the same frequency band and the same spreading code as the primary wireless terminal 1ae, the spreading code change packet and the spreading code change for changing the spreading code used for communication The instruction is output to the wireless signal processing unit 2a2. The radio signal processing unit 2a2 transmits the spreading code change packet to the opposing secondary wireless terminal, and changes the currently used spreading code to the spreading code included in the spreading code change instruction ( Step S90). The spreading code change packet includes the destination spreading code.
The opposing secondary radio terminal that has received the spreading code change packet analyzes the packet in the inter-terminal interface unit 2a3, and then outputs a spreading code change instruction to the radio signal processing unit 2a2. Then, the wireless signal processing unit 2a2 changes the currently used spreading code to the spreading code included in the spreading code change instruction.

  If interference is detected by the interference detection process of the primary wireless terminal 1ae even after the spreading code is changed, a secondary wireless terminal different from the secondary wireless terminal whose spreading code has been changed interferes with the primary wireless terminal 1ae. Therefore, the primary wireless terminal 1ae further increases the transmission power to expand the range in which the interference information packet reaches the secondary wireless terminal. Hereinafter, the radio communication system 100E repeats such processing until no interference is detected.

An outline of the operation of these wireless communication systems 100E will be briefly described.
In the state shown in FIG. 27, the secondary wireless terminals 2a to 2f are in operation, and no interference occurs in each application communication (2a and 2b, 2c and 2d, 2e and 2f).
Each secondary wireless terminal performs communication by transmitting signals using the following spreading codes.
Secondary wireless terminal 2a: {1,1,1,1,1,1,1,1}
Secondary wireless terminal 2b: {1,1, -1, -1,1,1, -1, -1}
Secondary wireless terminal 2c: {1, -1,-1,1,1, -1, -1,1}
Secondary wireless terminal 2d: {1,1,1,1, -1, -1, -1, -1}
Secondary wireless terminal 2e: {1, -1,1, -1, -1,1, -1,1}
Secondary wireless terminal 2f: {1,1, -1, -1, -1, -1,1,1}

In this case, processing when the primary wireless terminals 1ae and 1b start application communication is described below. Each primary wireless terminal 1ae, 1b performs communication using the following spreading codes.
Primary radio terminal 1ae: {1, -1,1, -1, -1,1, -1,1}
Primary wireless terminal 1b: {1,1, -1, -1,1,1, -1, -1}
It is assumed that all radio base stations and all radio terminals use the same frequency. At the start of application communication of the primary wireless terminal, as shown in FIG. 31, a portion where the non-interference area of the primary wireless terminal overlaps the non-interference area of the secondary wireless terminal is generated.
That is, since the primary wireless terminal 1ae and the secondary wireless terminal 2e use the same spreading code, the primary wireless terminal 1ae existing in the service area where the non-interference areas between the secondary wireless terminals 2e and 2f overlap is Interference is caused by the radio wave transmitted from the secondary wireless terminal 2e.

The primary wireless terminal performs interference detection processing in addition to normal application communication. For example, when the reception level observed by the interference detection process of the primary radio terminal 1ae is −75 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any of the secondary radio terminals. The Therefore, as shown in FIG. 32, the primary radio terminal 1ae radiates the radio wave carrying the interference information packet in all directions using the frequency for the interference information packet.
The secondary wireless terminal receives and analyzes the interference information packet. Then, the secondary wireless terminal 2e determines that the same frequency and the same spreading code are used, and changes the spreading code used for application communication as follows.
Secondary wireless terminal 2e: {1, -1,1, -1, -1,1, -1,1} → {1, -1, -1,1, -1,1,1, -1}

  Then, the secondary wireless terminal 2e transmits a spreading code change packet to the opposite (communication partner) secondary wireless terminal 2f, and transmits the changed spreading code. The secondary wireless terminal 2f instructs the wireless signal processing unit 2a2 to change the spreading code.

As described above, according to the wireless communication system 100E in the present embodiment, it is possible to easily and reliably prevent the interference from the secondary system to the primary system, and to improve the communication quality of the primary system.
In the present embodiment, the frequency for application communication is different from the frequency for transmission / reception of interference information packets, but the frequency for application communication and transmission / reception of interference information packets may be the same.

(Embodiment 8)
Next, an eighth embodiment of the present invention will be described.
33 to 40 show an eighth embodiment of the present invention.
The basic configuration of this embodiment is the same as that of the seventh embodiment, and only the differences will be described here.

FIG. 33 shows a system configuration of the wireless communication system 100F in the present embodiment.
The secondary radio base stations 21F, 22F, 23F, and 24F are assumed to transmit signals in packets.
The primary radio base station 1F and the secondary radio base stations 21F, 22F, 23F, and 24F communicate with each other by a CDMA communication method.
For spreading, an orthogonal spreading code with a spreading factor of 8 is used, and one of the two code sets is used.
The code set 1 includes the following.
C1 = {1,1,1,1,1,1,1,1}
C2 = {1, -1,1, -1,1, -1,1, -1}
C3 = {1,1, -1, -1,1,1, -1, -1}
C4 = {1, -1, -1,1,1, -1, -1,1}
The code set 2 includes the following.
C1 = {1,1,1,1, -1, -1, -1, -1}
C2 = {1, -1,1, -1, -1,1, -1,1}
C3 = {1,1, -1, -1, -1, -1,1,1}
C4 = {1, -1, -1,1, -1,1,1, -1}

In FIG. 33, all primary radio base stations and secondary radio stations communicate using the code set 1.
FIG. 34 is a block diagram showing the primary radio terminal 1af in the present embodiment.
The primary wireless terminal 1af includes a packet analyzer 1a9.
The packet analyzer 1a9 decodes the received signal and analyzes the decoded packet. Then, the packet analyzer 1a9 extracts the identifier included in the header added to the packet and outputs it to the base station-terminal interface unit 1a4.

FIG. 35 is a block diagram showing the secondary radio base station 21F in the present embodiment. The secondary radio base station 21 </ b> F includes a header addition unit 216.
The header adding unit 216 adds a header to a packet to be transmitted when performing normal application communication with the secondary wireless terminal. The header includes identifier information that is uniquely assigned to each secondary radio base station.

FIG. 36 is a block diagram showing the secondary radio terminal 2af in the present embodiment.
The secondary wireless terminal 2af includes a header adding unit 2a5.
The header addition unit 2a5 adds a header to a packet to be transmitted when performing normal application communication. The header includes identifier information that is uniquely assigned to the secondary radio base station that is connected to and communicates with the secondary radio terminal.

Next, the operation of the wireless communication system 100F configured in this way in the present embodiment will be described.
In the present embodiment, a different identifier is assigned to each secondary radio base station. The primary radio base station 1F has a correspondence table between secondary radio base stations and identifiers, and can identify secondary radio base stations from the identifiers.
When transmitting a packet in application communication, the secondary radio base station and the secondary radio terminal add a header for each packet.

FIG. 37 is a flowchart showing processing of the primary wireless terminal 1af.
Here, operations different from those of the seventh embodiment will be mainly described.
If the primary wireless terminal 1af determines that the reception level exceeds the threshold and the throughput is below the threshold (step S52; YES), the primary wireless terminal 1af stops normal application communication, switches to the reception mode, and receives a signal. Then, the primary radio terminal 1af analyzes the received signal (step S100) and transmits an interference information packet to the primary radio base station 1F (step S101).
That is, when the wireless signal processing unit 1a6 outputs the received signal to the packet analyzer 1a9, the packet analyzer 1a9 analyzes the received signal and extracts the identifier included in the header added to the packet. Then, the packet analyzer 1a9 outputs the extracted identifier to the base station-terminal interface unit 1a4. The base station-terminal interface unit 1a4 adds the extracted identifier to the interference information packet and outputs it to the radio signal processing unit 1a6 via the switch 1a5. The radio signal processor 1a6 transmits an interference information packet to the primary radio base station 1F via the antenna 1a1.

Next, a process (spreading code set changing process) for changing the spreading code set of the secondary radio base station that interferes with the primary radio terminal 1af will be described.
FIG. 38 is a flowchart showing a spreading code set change process of the wireless communication system 100F.
When the primary radio base station 1F receives the interference information packet from the primary radio terminal 1af, the base station-terminal interface unit 14 analyzes the packet and extracts an identifier (step S110). Then, the primary radio base station 1F extracts the secondary radio base station having the identifier from the correspondence table, and outputs interference information to the secondary radio base station (step S111). This interference information includes information on the frequency band and spreading code set used by the primary radio base station 1F.

The secondary radio base station to which the interference information is input uses the same frequency band as that used by the primary radio base station 1F, and is the same as the spreading code set used by the primary radio base station 1F. It is determined whether a spreading code set is used (step S112). If the secondary radio base station determines that the same frequency band and the same spreading code set are used (step S112: YES), the secondary radio base station sends a spreading code set change packet to all secondary radio terminals existing in the service area. Transmit (step S113), and the spreading code set used is changed. The spreading code set change packet includes spreading code set information of the change destination of the secondary radio base station.
The secondary wireless terminal that has received the spreading code set change packet immediately changes to the spreading code set included in the packet (step S114).

An outline of the operation of these wireless communication systems 100F will be briefly described.
As shown in FIG. 39, the secondary radio base station and the secondary radio terminal add a specific header for each base station before the packet to be transmitted. The header includes an identifier unique to each base station.
As shown in FIG. 40, when the secondary radio base station 24F starts operation, a portion where the non-interference area of the secondary radio base station 24F overlaps the non-interference area of the primary radio base station 1F is generated.
The primary radio terminal 1af existing in the service area where the non-interference areas of the secondary radio base station 24F overlap each other is interfered by radio waves transmitted from the secondary radio base station 24F or the secondary radio terminal 2bf existing in the service area. Will receive.
The primary wireless terminal 1af periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −76 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any secondary radio base station or secondary radio terminal.

Therefore, the primary wireless terminal 1af stops application communication and switches to the reception mode. The primary radio terminal 1af analyzes the received signal in the packet analyzer 1a9 and extracts an identifier. Further, the primary radio terminal 1af adds the extracted identifier to the interference information packet and transmits it to the primary radio base station 1F.
When receiving the interference information packet, the primary radio base station 1F extracts an identifier from the interference information packet, and outputs the interference information to the secondary radio base station 24F corresponding to the identifier.
The secondary radio base station 24F to which the interference information is input transmits the spreading code set change packet to all secondary radio terminals existing in the service area of the own radio base station. The spreading code set change packet includes an instruction to change to spreading code set 2. When the secondary radio base station 24F transmits the spreading code change packet, the secondary radio base station 24F changes the spreading code set used by the own radio base station from the code set 1 to the code set 2.
Similarly, the secondary wireless terminal 2b that has received the spreading code set change packet changes the spreading code set from code set 1 to code set 2.

    As described above, according to the wireless communication system 100F in the present embodiment, it is possible to easily and reliably prevent the interference from the secondary system to the primary system, and improve the communication quality of the primary system.

(Embodiment 9)
Next, a ninth embodiment of the present invention will be described.
41 to 46 show a ninth embodiment of the present invention.
The basic configuration of this embodiment is the same as that of the seventh embodiment, and only the differences will be described here.
FIG. 41 is a block diagram showing the primary radio terminal 1a in the present embodiment.
The primary radio terminal 1ag includes a correlator 1a10.
The correlator 1a10 calculates a correlation value from the received signal output from the wireless signal processing unit 1a6.

FIG. 42 is a block diagram showing the secondary radio base station 21G in the present embodiment.
The secondary radio base station 21 </ b> G includes a pattern adding unit 217.
The pattern adding unit 217 adds a pattern to a packet to be transmitted when performing normal application communication with the secondary wireless terminal. A pattern is uniquely assigned to each secondary radio base station.

FIG. 43 is a block diagram showing the secondary radio terminal 2ag in the present embodiment.
The secondary wireless terminal 2ag includes a pattern adding unit 2a6.
The pattern adding unit 2a6 adds a pattern to a packet to be transmitted when performing normal application communication. The pattern is uniquely assigned to the secondary radio base station with which the secondary radio terminal is connected to perform communication.

Next, the operation of the wireless communication system 100 configured in this way in the present embodiment will be described.
In the present embodiment, a different pattern is assigned to each secondary radio base station. The primary radio base station 1 has a correspondence table between secondary radio base stations and patterns, and can identify a secondary radio base station from the pattern.
When the secondary radio base station and the secondary radio terminal transmit a packet in application communication, a pattern is added to each packet.

FIG. 44 is a flowchart showing the processing of the primary wireless terminal 1ag.
Here, operations different from those of the seventh embodiment will be mainly described.
If the primary wireless terminal 1ag determines that the reception level exceeds the threshold and the throughput is below the threshold (step S52; YES), the primary wireless terminal 1ag stops normal application communication, switches to the reception mode, and receives a signal. Then, the primary radio terminal 1ag calculates a correlation value between the pattern added to the received packet and a plurality of patterns stored in advance in the correlator 1a10 (step S120). Then, the primary radio terminal 1ag adds the pattern information for which the highest correlation value has been calculated to the interference information packet (step S121), and transmits it to the primary radio base station (step S122).

Next, a process (frequency change process) for changing the frequency of the secondary radio base station 24G that interferes with the primary radio terminal 1ag will be described.
FIG. 45 is a flowchart showing frequency change processing of the wireless communication system 100.
When the primary radio base station 1 receives the interference information packet from the primary radio terminal 1ag, the base station-terminal interface unit 14 analyzes the interference information packet and extracts the pattern information (step S130). Then, the primary radio base station 1 extracts the secondary radio base station having the pattern information from the correspondence table, and outputs interference information to the secondary radio base station (step S131). In this interference information, information on the frequency band used by the primary radio base station 1 is stored.

The secondary radio base station to which the interference information is input determines whether the same frequency band as that used by the primary radio base station 1 is used (step S132). And when it determines with the secondary radio base station using the same frequency band (step S132: YES), a frequency change packet is transmitted to all the secondary radio terminals which exist in the service area (step S133), Change the frequency being used. The frequency change packet includes information on the frequency band to which the secondary radio base station is changed.
The secondary wireless terminal that has received the spreading code set change packet immediately changes to the frequency included in the packet (step S134).

An outline of the operation of these wireless communication systems 100 will be briefly described.
As shown in FIG. 46, the secondary radio base station and the secondary radio terminal add a specific pattern for each base station before the packet to be transmitted.
The pattern assigned to each secondary radio base station is shown below.
Secondary radio base station 21G: {1,1,1,1}
Secondary radio base station 22G: {1, -1,1, -1}
Secondary radio base station 23G: {1,1, -1, -1}
Secondary radio base station 24G: {1, -1, -1,1}

The primary wireless terminal 1ag periodically performs interference detection processing. For example, when the reception level observed by the interference detection process is −75 dBm and the measured throughput is 4 Mbit / s, it is determined that interference is received from any secondary radio base station or secondary radio terminal.
Therefore, the primary wireless terminal 1ag stops application communication and switches to the reception mode. The primary radio terminal 1ag stores all the above patterns in a memory in the correlator 1a10. In the correlator 1a10, the correlation value between the pattern added to the received signal and the pattern stored in advance in the memory. Is calculated. The correlation value with each pattern for the secondary radio base station 24G is as follows.
Pattern 1: 0
Pattern 2: 0
Pattern 3: 0
Pattern 4: 4

However, these values are values when changes in the received signal due to factors such as distance attenuation of radio field intensity, shadowing, fading, and noise are not considered.
The primary radio terminal 1ag adds the number of the pattern 4 for which the highest correlation value has been calculated to the interference information packet and transmits it to the primary radio base station 1.
When receiving the interference information packet, the primary radio base station 1 extracts a pattern number from the interference information packet and outputs the interference information to the secondary radio base station 24G having the pattern.
The secondary radio base station 24G to which the interference information is input transmits a frequency change packet to all the secondary radio terminals existing in the service area of the own radio base station, and changes the frequency band used by the own radio base station. .
The secondary wireless terminal that has received the frequency change packet changes the frequency band to be used.

  As described above, according to the wireless communication system 100 of the present embodiment, it is possible to easily and reliably prevent interference from the secondary system to the primary system, and improve the communication quality of the primary system.

In the first to ninth embodiments, the packets such as the interference information packet and the application communication packet are identified. The packet identification is performed by the packet identification unit 13 or the like reading the header of each packet. Is.
In addition, the primary radio base station, the secondary radio base station, or the management station investigates the secondary radio base station in which the non-interference area overlaps the service area of the primary radio base station. Is done. That is, the distance between the primary radio base station and the secondary radio base station is compared with the total value of the radius of the non-interference area of the primary radio base station and the radius of the non-interference area of the secondary radio base station. If it is determined that the distance is smaller than that, the non-interference areas overlap. On the other hand, if it is determined that the distance is larger than the total value, the non-interference areas do not overlap. In this way, the investigation is performed. Note that transmission power may be used instead of the distance.

In addition, the base station-terminal interface unit 14 analyzes the interference information packet. This analysis is performed by reading out information (information indicating that there is interference) included in the interference information packet. is there. That is, when the base station-terminal interface unit 14 reads information indicating that there is interference from the interference information packet, the base station-terminal interface unit 14 outputs this information to the inter-base station interface unit 15 as interference information.
In the eighth and ninth embodiments, the identifier and the specific pattern are used to specify the interfering station. However, the present invention is not limited to this. For example, the location of each radio base station, the transmission Power, cell radius, etc. may be used.
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 is a system configuration diagram showing a first embodiment of a wireless communication system according to the present invention. It is a block diagram which shows the primary radio | wireless terminal in the same embodiment. It is a block diagram which shows the primary radio base station in the embodiment. It is a block diagram which shows the secondary radio base station in the embodiment. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows operation | movement of the primary radio | wireless terminal in the same embodiment. 5 is a flowchart showing an operation stop processing operation of the wireless communication system in the embodiment. It is explanatory drawing which shows a mode that the non-interference area of the secondary radio base station in the embodiment overlaps with the non-interference area of the primary radio base station. It is a figure which shows 2nd Embodiment of the radio | wireless communications system which concerns on this invention, Comprising: It is a block diagram which shows a primary radio | wireless terminal. It is a block diagram which shows the secondary radio base station in the embodiment. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows the process of the primary radio | wireless terminal in the embodiment. It is a flowchart which shows the frequency change process of the radio | wireless communications system in the embodiment. It is a system configuration figure showing a 3rd embodiment of the radio communications system concerning the present invention. It is a block diagram which shows the primary radio base station in the embodiment. It is a block diagram which shows the secondary radio base station in the embodiment. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows the transmission power change process of the radio | wireless communications system in the embodiment. It is explanatory drawing which shows the distance between the wireless base stations in the embodiment. It is explanatory drawing which shows a mode that the non-interference area of the secondary radio base station in the embodiment overlaps with the non-interference area of the primary radio base station. It is a figure which shows 4th Embodiment of the radio | wireless communications system which concerns on this invention, Comprising: It is a block diagram which shows a primary radio | wireless terminal. It is a block diagram which shows the primary radio base station in the embodiment. It is a flowchart which shows the process of the primary radio | wireless terminal in the embodiment. It is a flowchart which shows the operation | movement stop process of the radio | wireless communications system in the embodiment. It is a system configuration figure showing a 6th embodiment of the radio communications system concerning the present invention. It is a flowchart which shows the operation | movement stop process of the radio | wireless communications system in the embodiment. It is a system block diagram which shows 7th Embodiment of the radio | wireless communications system which concerns on this invention. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows operation | movement of the primary radio | wireless terminal in the same embodiment. It is a flowchart which shows the process of the secondary radio | wireless terminal in the embodiment. It is explanatory drawing which shows a mode that the non-interference area of the primary radio | wireless terminal in the embodiment overlaps with the non-interference area of a secondary radio | wireless terminal. It is explanatory drawing which shows a mode that the primary radio | wireless terminal in the embodiment radiates | emits the electromagnetic wave which carried the interference information packet to all directions using the frequency for interference information packets. It is a system block diagram which shows 8th Embodiment of the radio | wireless communications system which concerns on this invention. It is a block diagram which shows the primary radio | wireless terminal in the same embodiment. It is a block diagram which shows the secondary radio base station in the embodiment. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows the process of the primary radio | wireless terminal in the embodiment. It is a flowchart which shows the spreading code set change process of the radio | wireless communications system in the embodiment. It is explanatory drawing which shows the structure of the packet in the embodiment. It is explanatory drawing which shows a mode that the non-interference area of the primary radio | wireless terminal in the embodiment overlaps with the non-interference area of a secondary radio | wireless terminal. It is a figure which shows 9th Embodiment of the radio | wireless communications system which concerns on this invention, Comprising: It is a block diagram which shows a primary radio | wireless terminal. It is a block diagram which shows the secondary radio base station in the embodiment. It is a block diagram which shows the secondary radio | wireless terminal in the same embodiment. It is a flowchart which shows the process of the primary radio | wireless terminal in the embodiment. It is a flowchart which shows the frequency change process of the radio | wireless communications system in the embodiment. It is explanatory drawing which shows the structure of the packet in the embodiment.

Explanation of symbols

1 Primary radio base station (primary radio communication station)
21, 22, 23, 24, 25, 26, 27, 28, 29, 30 Secondary radio base station (secondary radio communication station)
3 management station 1a2 reception level observation part (interference detection means)
1a3 comparator (interference detection means)
1a7 Error rate measurement unit (interference detection means)
1a8 Throughput measurement unit (interference detection means)
15 Inter-base station interface section (interference information transmitting means, interference station specifying means)
212 Radio signal processor (interference avoidance means)
214 Base station-terminal interface section (interference avoidance means)
215 Interface section between base stations (interference avoidance means)
100 Wireless communication system

Claims (7)

A wireless communication system having a primary wireless communication station that can preferentially use a frequency and a secondary wireless communication station that uses the frequency in a range that does not interfere with communication of the primary wireless communication station,
The primary wireless communication station is
Interference detecting means for detecting interference from the secondary wireless communication station and generating interference information;
Interference information transmission means for transmitting the interference information generated by the interference detection means to the secondary wireless communication station,
The secondary wireless communication station is
Interference avoiding means for avoiding interference based on interference information transmitted from the interference information transmitting means ,
The primary wireless communication station is
Has information about itself and the secondary wireless communication station,
The primary wireless communication station is
A wireless communication system, wherein the interference information is transmitted to a secondary wireless communication station existing within a certain distance from itself, and a range in which the interference information is transmitted is expanded until the interference detection unit detects no interference . A wireless communication system having a primary wireless communication station that can preferentially use a frequency and a secondary wireless communication station that uses the frequency in a range that does not interfere with communication of the primary wireless communication station,
The primary wireless communication station is
Interference detecting means for detecting interference from the secondary wireless communication station and generating interference information;
Interference information transmission means for transmitting the interference information generated by the interference detection means to the secondary wireless communication station,
The secondary wireless communication station is
Interference avoiding means for avoiding interference based on interference information transmitted from the interference information transmitting means ,
The interference information includes the number of interference avoidance hops indicating the range of the secondary wireless communication station that instructs interference avoidance,
The secondary wireless communication station is
Depending on the number of interference avoidance hops, output interference avoidance instructions to other secondary wireless communication stations,
The primary wireless communication station is
A radio communication system, characterized in that the number of interference avoidance hops is increased until the interference detection means detects no interference . The primary wireless communication station is
Information about the self and the secondary wireless communication station has an interference station identifying means for identifying the secondary radio station is causing interference from the interference information,
The primary wireless communication station is
The radio communication system according to claim 1 or 2 , wherein the interference information is transmitted to a secondary radio communication station that is the cause of the interference specified by the interference station specifying means. The interference station specifying means includes:
Identifying an interference station from the position of each wireless communication station, transmission power, cell radius, identifier in the data being communicated by the secondary wireless communication station, or a specific pattern in the data being communicated by the secondary wireless communication station. The wireless communication system according to claim 3. The interference avoiding means is means for changing at least one of the communication frequency, communication method, modulation method, transmission power, antenna directivity, and polarization of the secondary wireless communication station, or the secondary wireless communication station The wireless communication system according to any one of claims 1 to 4 , wherein the wireless communication system is means for stopping operation. The wireless communication system of the primary wireless communication station and the secondary wireless communication station is a CDMA communication system,
The wireless communication system according to any one of claims 1 to 4 , wherein the interference avoiding means is means for changing a spreading code of the secondary wireless communication station. The interference detection means, received power level, error rate, throughput, spectrum of the received signal, one of claims 1 to 6, characterized by measuring at least one of the periodicity of received signals one The wireless communication system according to item.

Images