JP2012029177A - Coexistence manager of cognitive radio system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system and a radio communication method which can avoid interference even when networks including multiple secondary users coexist.SOLUTION: The present invention relates to a spectrum processing method in a cognitive radio. First of all, a coexistence manager (CM) of the Internet obtains sensing information and information about a first secondary user (1,1) and a second secondary user (2,1) connected via the coexistence manager (CM) of the Internet and a transport service access point (T-SAP) from a database connected via an application service access point (A-SAP). Based on the information, the CM decides the spectrum and transmits it.

Description

  The present invention relates to a radio communication method using a coexistence manager of a cognitive radio system.

  In a wireless communication system, communication (communication service) of a communication device is enabled by assigning a frequency to the communication device. However, at present, it is difficult to assign frequencies to the latest applications and services. The reason is that the spectrum is saturated because a predetermined frequency band is already assigned to various services by a regulatory body. In contrast to this saturation state, there is actually a frequency band not occupied by the spectrum, and the load on the spectrum is not very large.

  The US Federal Communications Commission (FCC) published a document prepared by the Spectrum Policy Task Force (SPTF) in 2002. This document is about efficient use of the radio spectrum. Specifically, by allowing an unlicensed wireless service to access an unoccupied spectrum as described above, the wireless spectrum can be used efficiently.

  There is a cognitive radio technology as a radio technology that uses an unoccupied spectrum. In a cognitive radio communication system using cognitive radio technology, a secondary user first specifies a spectrum that is not temporarily used by a primary user. Here, the primary user is a user who is licensed to use spectrum. Subsequently, the secondary user starts communication using the specified radio spectrum. This enables efficient use of the radio spectrum.

  However, when there are a plurality of secondary users and each secondary user specifies a spectrum and starts communication, there is a problem that interference occurs between the plurality of secondary users. In particular, when a plurality of secondary users belong to different networks or when different communication protocols are used, the above-described problem becomes significant.

  In order to solve the above problem, for example, the IEEE standardization group is researching how to manage the coexistence of a plurality of different wireless networks. As a result of previous research on such coexistence, it is possible to realize coexistence by a collaborative method or a non-cooperative method in consideration of information exchange between multiple wireless networks. . However, such research mainly focuses on different primary user networks (also called legacy wireless networks). Here, examples of coexistence of a plurality of different legacy wireless networks include a network based on IEEE 802.11 and a network based on IEEE 802.15. Therefore, there has been little research on the coexistence of networks including secondary users with other networks.

  Here, when considering coexistence of multiple secondary user networks, it is considered necessary to consider requirements different from those of legacy wireless networks. Specifically, the following points must be taken into account, and coexistence is not easy.

  First, in order to realize the coexistence of the secondary user network, it is necessary to consider interference with the primary user network. Normally, each secondary user is configured to access a spectrum that is not temporarily used by the primary user. Therefore, a situation may occur in which a plurality of secondary users access the same spectrum. When such a situation occurs, there is a possibility that interference may occur with the primary user.

  Second, even if the co-existence of the secondary user network is realized, the secondary user network may need to be reconfigured, and such a reconfiguration scheme must be considered.

  Third, it must be taken into account that the information necessary to determine access to the spectrum needs to be made available (or accessible). For example, in a cognitive radio communication system, there are two types of information necessary for access determination: sensing information and regulation information. However, according to Non-Patent Document 1, the regulation information is stored in a location different from the sensing information. As described above, when there are a plurality of pieces of information necessary for determining access and the information is stored in individual databases, it is not easy to configure the plurality of pieces of information to be available.

“SECOND REPORT AND ORDER AND MEMORANDUM OPINION AND ORDER”, FCC (Federal Communications Commission), Document No. FCC 08-260, November 14, 2008

  An object of the present invention is to provide a wireless communication system and a wireless communication method capable of avoiding interference even when a network including a plurality of secondary users coexists.

  The present invention relates to a spectrum processing method in cognitive radio. First, an Internet coexistence manager (CM) detects sensing information and the Internet coexistence manager (CM) and a transport service access point (T-SAP) from a database connected via an application service access point (A-SAP). ) To obtain information on the first secondary user (1, 1) and the second secondary user (2, 1) connected via the Internet.

  Next, the Internet coexistence manager (CM) uses the sensing information collected in the information collecting step, the information about the first secondary user (1,1) and the second secondary user (2,1), The first secondary user (1,1) and the second secondary user (2,1) are searched for a spectrum that can be used without interference, and the first secondary user (1,1) and the second secondary user ( 2) If a spectrum that can be used without interference is found, the spectrum is determined and can be used without interference for the first secondary user (1,1) and the second secondary user (2,1). If no spectrum is found, go back to the information gathering process and get the information again. It performs the determined Zui.

  Thereafter, the coexistence manager (CM) of the Internet transmits information regarding the determined spectrum to the first secondary user (1, 1) and the second secondary user (2, 1).

  According to the present invention, it is possible to provide a wireless communication system and a wireless communication method capable of avoiding interference even when a network including a plurality of secondary users coexists.

FIG. 1 is a flowchart for explaining the method of the present invention. FIG. 2 is a diagram showing the basic configuration of the coexistence manager. FIG. 3 is a diagram illustrating an example of a cognitive radio mounting system. FIG. 4 is a diagram for explaining a process for coexistence management for realizing this method. FIG. 5 schematically shows a reference model of the interface of the present invention. FIG. 6 is a block diagram schematically showing an example of the configuration of the cognitive radio communication system of the present invention. FIG. 7 is a flowchart showing a procedure of coexistence management processing executed by the coexistence manager (CM) in FIG. FIG. 8 is a block diagram schematically showing the configuration of another example of the wireless communication system shown in FIG. FIG. 9 is a block diagram schematically showing the configuration of still another example of the wireless communication system shown in FIG. FIG. 10 is a block diagram schematically showing the configuration of still another example of the wireless communication system shown in FIG. FIG. 11 is a graph showing a simulation result.

  Hereinafter, the method of the present invention will be described. FIG. 1 is a flowchart for explaining the method of the present invention. As shown in FIG. 1, the method of the present invention includes an information acquisition step for acquiring information for determining a spectrum for which information can be used, and a determination for determining a spectrum that can be used by the SU based on the obtained information. A process and a transmitting process of transmitting the determined information to the SU.

  As shown in FIG. 1, first, an Internet coexistence manager (CM) obtains sensing information from the database connected via an application service access point (A-SAP) and the Internet coexistence manager (CM) and a transformer. Information about the first secondary user (1, 1) and the second secondary user (2, 1) connected via the port service access point (T-SAP) is acquired.

  Next, the Internet coexistence manager (CM) uses the sensing information collected in the information collecting step, the information about the first secondary user (1,1) and the second secondary user (2,1), The first secondary user (1,1) and the second secondary user (2,1) are searched for a spectrum that can be used without interference, and the first secondary user (1,1) and the second secondary user ( 2) If a spectrum that can be used without interference is found, the spectrum is determined and can be used without interference for the first secondary user (1,1) and the second secondary user (2,1). If no spectrum is found, go back to the information gathering process and get the information again. It performs the determined Zui.

  Thereafter, the coexistence manager (CM) of the Internet transmits information regarding the determined spectrum to the first secondary user (1, 1) and the second secondary user (2, 1).

  Next, a coexistence manager (CM) for realizing the above method will be described. Since a coexistence manager (CM) exists, cognitive radio communication can be performed. Even if there are multiple secondary users who are not licensed, different cognitive radio communications that cause interference can be realized. To this end, information must be exchanged between the elements. FIG. 2 is a diagram illustrating a reference model of the coexistence manager (CM).

  As shown in FIG. 2, the basic functions of the coexistence manager (CM) are M-SAP, T-SAP, and A-SAP. That is, since the common manager functions as a service access point for various elements, it is possible to grasp and use the spectrum that can be used for the secondary user network / device.

  An example of a process for managing two secondary user (SU) networks is as follows. FIG. 3 is a diagram illustrating an example of a cognitive radio mounting system. As shown in FIG. 3, the first secondary user (1, 1) and the second secondary user (2, 1) each have a coexistence manager (CM). These two coexistence managers (CM) realize two functions. That is, the CM acquires information from the SU network (or SU device) and transmits a command to the SU network (or SU device). The spectrum usage database and the regulation database are available via the Internet. Furthermore, the coexistence manager (CM) can also be accessed via the Internet. The functions of the Internet Coexistence Manager (CM) include accessing the database and issuing instructions on coexistence suggestions, decisions and rebuilds. These three devices can be accessed using IP addresses.

  Since SU (1, 1) and SU (2, 1) are license users, they can access the Internet through a certain frequency band. Therefore, the coexistence manager (CM) of the first secondary user (1,1) and the coexistence manager (CM) of the second secondary user (2,1) send information on the respective SU network or SU device to the Internet. To the coexistence manager (CM). The Internet coexistence manager (CM) sends information on coexistence status, commands, and restructuring instructions via the SU (1,1) CM and SU (2,1) CM. Send to (2,1). In this way, the SU network or the SU device can reconstruct operation conditions such as the time slot allocation rate and the transmission output for coexistence in order to realize coexistence. This feature is independent of SU network RAT (Radio Access Technology), and therefore allows information exchange and information adjustment between different networks.

  FIG. 4 is a diagram for explaining a process for coexistence management for realizing this method.

First Information Collection Step Before the first secondary user (SU) network starts communication, the coexistence manager (CM) of the first secondary user (1, 1) contacts the coexistence manager (CM) on the Internet. Then, the coexistence manager (CM) of the first secondary user (1, 1) provides the location information and information on the desired spectrum use area in information collection to the coexistence manager (CM) of the Internet.

  On the other hand, the coexistence manager (CM) of the Internet reads out information about available channels from the spectrum utilization database in addition to reading out a division method for available channels from the regulation database. Information about available spectrum may include a list of secondary user networks.

First Decision Step Following the information collection step, the Internet coexistence manager (CM) proceeds to the first decision step. In the determination step, an available spectrum is determined. The information obtained and stored in the information collecting process is read out, and the Internet coexistence manager (CM) examines the availability of the spectrum and determines the available spectrum.

First Information Transmission Step An Internet coexistence manager (CM) determines whether or not a secondary user (SU) network coexists. This determination method is known. If there is only one secondary user (SU) network and there is no problem of the coexistence of the SU network, the Internet coexistence manager (CM) will send information on permission to use the spectrum to the first secondary user (1,1). Send to coexistence manager (CM).

  Further, the Internet coexistence manager (CM) registers the first secondary user (1,1) network in the spectrum utilization database. Such registration work is completed in this information transmission step.

Second information collecting step When the second secondary user (SU) network starts communication, the coexistence manager (CM) of the second secondary user (2, 1) contacts the coexistence manager (CM) of the Internet. Take.

Second Determination Step Next, the Internet coexistence manager (CM) determines the available spectrum.

Second Information Transmission Step If there is a coexistence problem, the Internet coexistence manager (CM) provides a solution to the coexistence manager (CM) of the second secondary user (2, 1).

Third information collecting step If the solution provided by the Internet coexistence manager (CM) is not accepted by the second secondary user (SU) network, the coexistence manager of the second secondary user (2,1) ( When the CM determines, the coexistence manager (CM) of the second secondary user (2, 1) requests the Internet coexistence manager (CM) to provide another solution. When this request is made, the Internet coexistence manager (CM) collects information again.

Third Determination Step Next, the Internet coexistence manager (CM) makes a determination regarding coexistence other than the above. According to the decision, the CM seeks a new solution for coexistence.

Third information transmission step The coexistence manager (CM) of the Internet sends the coexistence manager (CM) of the first secondary user (1,1) to the coexistence manager (CM) of the second secondary user (2,1). , Issue a rebuild command.

  FIG. 5 schematically shows a reference model of the interface of the present invention. FIG. 5 is an example in which two secondary users coexist.

  An Internet coexistence manager (CM) is connected to a database via an application service access point (A-SAP). The database includes a regulation database and a spectrum utilization database. On the other hand, an Internet coexistence manager (CM) is connected to a transport system via a transport service access point (T-SAP). An example of a transportation system is the Internet. Note that

  The first secondary user (1, 1) has a coexistence manager (CM) of the first secondary user (1, 1). The CM is connected to a first SU network including a TVBD device or a network via a media service access point (M-SAP). The CM is connected to the transport system via a transport service access point (T-SAP). TVBD is an abbreviation for TV band device, and is a wireless device for using a white space.

  The second secondary user (2, 1) also has the same configuration as the first secondary user (1, 1).

  The coexistence manager (CM) of the first secondary user (1,1) and the coexistence manager (CM) of the second secondary user (2,1) are connected via the transport service access point (T-SAP). The coexistence manager (CM) can be accessed, and the protocol stack can be used.

  FIG. 6 is a block diagram schematically showing an example of the configuration of the wireless communication system of the present invention. The wireless communication system 1 shown in FIG. 6 is, for example, a cognitive wireless communication system, and includes a primary user network 10 as a legacy wireless network and a first secondary user network 20 (hereinafter also referred to as a first network 20). , A second secondary user network 30 (hereinafter also referred to as a second network 30). The wireless communication system 1 is not limited to a cognitive wireless communication system, and may be any system that includes a dynamically accessible network.

  One or more primary users 11 belong to the primary user network 10. The primary user 11 may be any device that is configured to be capable of wireless communication. For example, the primary user 11 may be a device that complies with IEEE 802.11 or IEEE 802.15. In addition, the area where the primary user 11 can communicate in the primary user network 10 is determined by the base station (base station) 12.

  One or more first secondary users 21 belong to the first secondary user network 20. The first secondary user 21 may be any device configured to be capable of wireless communication, but is preferably a device configured to be capable of cognitive wireless communication. Further, the area where the first secondary user 21 can communicate in the first secondary user network 20 is determined by the base station (base station) 22.

  One or more second secondary users 31 belong to the second secondary user network 30. The second secondary user 31 may be any device configured to be capable of wireless communication, but is preferably a device configured to be capable of cognitive wireless communication. In addition, an area in which the second secondary user 31 can communicate in the second secondary user network 30 is determined by a base station (base station) 32.

  The wireless communication system 1 further includes a database 40 and a coexistence manager (CM) 50.

  The database 40 is used to store information necessary for wireless communication control, and is disposed at a position accessible from the base stations 12, 22, 32, and the like. The database 40 may be a data archive (DA) configured to be communicable. Preferably, the database 40 is a data archive specified by IEEE 1900.6 or a regulatory information storage location specified by the FCC. More preferably, the database 40 is used for cognitive radio communication. It is a database (white space sensing database (WSD)) that stores both sensing information (information relating to white space) and regulation information necessary for control. Preferably, the database 40 stores information in primitives and data formats that can be interpreted by the coexistence manager (CM) 50. Preferably, the database 40 is arranged at a position accessible from the coexistence manager (CM) 50.

  The coexistence manager (CM) 50 is a new device for solving the above-described coexistence problem, and is specifically a logical element. In the example shown in FIG. 6, the coexistence manager (CM) is a stand-alone type, and is installed at an arbitrary position in the wireless communication system 1. The coexistence manager (CM) 50 is not limited to a stand-alone type. For example, the coexistence manager (CM) 50 may be mounted on the primary user 11 or the secondary users 21 and 31. It may be mounted on the base stations 12, 22, 32. However, the coexistence manager (CM) 50 is installed in an area where communication with the primary user 11 and the secondary users 21 and 32 is possible. Further, in this aspect, the coexistence manager (CM) can communicate with the base station 22 and the base station 32, thereby acquiring information from the database 40 via the base station 22 and the base station 32. . In the example shown in FIG. 6, the coexistence manager (CM) 50 is installed so as to be able to communicate with both of the secondary user networks 20 and 30 and is configured to perform central control. However, the installation of the coexistence managers (CMs) is not limited to this. For example, the coexistence managers (CMs) may be distributed or distributed in each network. In this case, a plurality of coexistence managers (CMs) may be installed. Information exchange is possible between them (see FIGS. 8 and 9). Note that a coexistence manager (CM) may not be installed in all of a plurality of networks.

  By installing the coexistence manager (CM) 50 in the wireless communication system 1, it is possible to manage the spectrum usage by a plurality of secondary users to avoid mutual interference and to avoid interference with the primary user. . In order to realize this, the coexistence manager (CM) 50 is configured to have at least some of the following functions.

  First, the coexistence manager (CM) 50 is configured to be able to access the database 40. In this embodiment, the coexistence manager (CM) 50 accesses the database 40 via the base station 22 and the base station 32.

  As a result, the coexistence manager (CM) 50 can acquire sensing information from the database 40. Here, the sensing information includes information on the usage status of the spectrum in a predetermined area. In particular, in this aspect, the sensing information includes information on a spectrum usage state in a specific area where a plurality of different networks of secondary users are trying to share a wireless environment. Further, the coexistence manager (CM) 50 can acquire sensing information from the database 40. Here, the regulation information includes, for example, information on which frequency is not used, or information on available frequencies (for example, a list of available channels).

  Second, the coexistence manager (CM) 50 maintains information regarding one or more primary users. Here, the information about the primary user includes information about the spectrum usage status and information about the MAC. Preferably, the information regarding the primary user includes information regarding the geographical position of the primary user and information regarding the geographical position of the wireless receiver of the primary user. That is, the coexistence manager (CM) 50 preferably holds information regarding the geographical location of the primary user and information regarding the geographical location of the primary user's wireless receiver. Then, the coexistence manager (CM) 50 uses the information about the primary user to derive a requirement required for the secondary user as a requirement for protecting the primary user.

  Thirdly, the coexistence manager (CM) 50 is configured to be able to hold information regarding a plurality of secondary user networks (for example, the first and second networks 20 and 30). Here, the information regarding the secondary user network includes information regarding the PHY of each network, information regarding the MAC, and information regarding the channel usage status. Preferably, the information regarding the secondary user network includes information of a layer higher than the PHY layer and the MAC layer.

  Fourth, the coexistence manager (CM) 50 is configured to be able to hold information regarding available channels (ie, spectrum opportunities). The information on the available channel is, for example, information on a channel that is not currently used by the primary user and that can be accessed by the secondary user. Information on available channels can be obtained from sensing information from the database 40. In addition, information regarding available channels can be acquired from the restriction information from the database 40. According to the FCC, when a device uses a television white space, each device is required to check a database to identify an accessible unused channel.

  Fifth, the coexistence manager (CM) 50 is configured to be able to generate coexistence rules (for example, policy information) and parameters based on information held or by following an algorithm. This parameter is information for prompting the secondary user's network to execute reconfiguration according to the parameter. For example, the coexistence manager (CM) 50 prompts the secondary user to change the transmission output, change the packet size, change the channel usage status, etc., based on the channel information (for example, channel information such as RSSI). That is, the coexistence manager (CM) 50 can coordinate different secondary user networks by using information on the secondary user network. The coexistence rule is information for protecting the order of coexistence by complying with each secondary user.

  Specifically, the coexistence manager (CM) acquires a coexistence rule for enabling the coexistence of the second network from a predetermined database when the interference occurs in the target network, and acquires it from the database. From the coexistence rules, a control message necessary for coexistence of the second network and the third network, and parameters and rules necessary for reconstructing at least one of the second network and the third network are generated. Here, the predetermined database may be stored in a storage device provided in the coexistence manager (CM) 50 or may be stored in another source. Then, the coexistence manager (CM) 50 transmits (provides) the generated information (control message, parameter, and rule) to the corresponding secondary user. When a plurality of networks are targeted, information generated by the coexistence manager (CM) 50 is provided to secondary users belonging to at least one network. Thereby, generation | occurrence | production of interference can be suppressed more reliably.

  Specifically, for this coordination, the coexistence manager (CM) 50 adjusts the parameters of the secondary user network (for example, transmission power, occupied frequency, data rate, packet size) or newly sets a coexistence rule. Or set.

  Preferably, the coexistence manager (CM) 50 defines the value indicating the transmission quality of the secondary user divided by the value of the negative interference with the primary user as the coexistence quality (QoS), and uses this coexistence quality value as a coexistence value. It is used as a criterion for determining performance at the time, and parameters related to transmission output and time slot allocation are adjusted. In this way, it is possible to adjust parameters after evaluating both the spectrum utilization efficiency and the degree of interference with the primary user. Then, the first secondary user and the second secondary user use the spectrum home within the assigned time slot (that is, in a time division manner). Thereby, even if a plurality of networks coexist in the wireless communication system 1, the performance can be improved.

  By configuring the coexistence manager (CM) 50 as described above, the wireless communication system 1 realizes management for avoiding interference between a plurality of secondary users. In particular, the coexistence manager (CM) 50 adjusts parameters, sets coexistence rules, and the like, thereby optimizing when multiple networks share spectrum opportunities, thereby improving the spectrum efficiency (that is, the performance of the wireless communication system 1). ) Can be maximized.

  Next, network management processing executed by the coexistence manager (CM) 50 will be described in detail with reference to FIG. This network management process manages the coexistence of multiple networks.

  FIG. 7 is a flowchart showing a procedure of network management processing executed by the coexistence manager (CM) 50 in FIG. For example, when the first secondary user network 20 starts to use the specified spectrum opportunity (spectrum hall), the process shown in FIG. This is particularly effective when a coexistence state occurs due to access to the same spectrum hall. Note that the program (algorithm) corresponding to FIG. 7 is recorded on, for example, a recording medium, and the coexistence manager (CM) 50 reads out and executes this program, whereby processing corresponding to FIG. 7 is performed.

  In FIG. 7, first, in step S110, the coexistence manager (CM) 50 obtains a list of available channels (spectrum opportunities) through a dedicated control channel as shown in FIG. Here, the dedicated control channel may be realized by a dedicated frequency, or may be realized by using a specified spectrum opportunity.

  Here, the usable channel is a channel that is not temporarily used by the primary user network 10. The available channels can be specified by the coexistence manager (CM) 50 accessing the database 40 and obtaining sensing information and / or regulation information. Regarding the white space for television, the restriction information database defined by the FCC holds information on channels that are not used at specific positions. Therefore, the coexistence manager (CM) can confirm an available channel based on the geographical position of the primary user network 10. Similarly, the first secondary user network 20 can also confirm the information about the specified spectrum hall (a list of available channels) and its usage status.

  In step S120, when the first secondary user network 20 has already started using the spectrum hall and the second secondary user network 30 is going to use the spectrum hall, the second secondary user network 20 The network 30 inquires of the coexistence manager (CM) 50 about available channels. That is, the coexistence manager (CM) 50 receives an inquiry about available channels from the second secondary user network 30.

  If there is a channel that is not used by the first secondary user network 20 among a plurality of available channels (YES in step S130), the second secondary user network 30 uses the channel. Then, a beacon or a test signal is transmitted as a pilot signal (step S140).

  Since the coexistence manager (CM) 50 has already accessed the first secondary user network 20, the coexistence manager (CM) 50 can make an inquiry to the first secondary user 21. is there. In step S150, the coexistence manager (CM) 50 makes an inquiry to the first secondary user network 20. Here, the content to be inquired is related to whether or not the second secondary user network 30 detects (senses) interference when the first secondary user network 20 senses a beacon or a test signal. . Instead of inquiring, the coexistence manager (CM) 50 may confirm whether there is an interference alarm.

  In response to the above inquiry, when the coexistence manager (CM) 50 receives that the first secondary user network 20 has received interference (YES in step S160), the coexistence manager (CM) 50 The network 20 and 30 for reconfiguration is proposed (step S200). Such a reconfiguration proposal can be realized by the coexistence manager (CM) 50 transmitting control messages, reconfiguration parameters, and rules to the secondary user networks 20 and 30.

  When the coexistence manager (CM) 50 receives that there is no interference in the first secondary user network 20 (NO in step S160), the coexistence manager (CM) 50 includes two networks 20 coexisting in the same frequency band. It is confirmed whether or not 30 accepts the possibility of generating interference to the primary user network 10 (step S170).

  If there is a possibility of interference (YES in step S170), the coexistence manager (CM) 50 proposes reconfiguration based on the parameters of the secondary user networks 20 and 30 (step S200).

  On the other hand, when there is no possibility of interference (NO in step S170), the coexistence manager (CM) 50 can realize the coexistence of the two secondary user networks 20 and 30. Specifically, the second secondary user network 30 registers the frequency band (for example, the frequency band of the television white space) used by the network 30 in the coexistence manager (CM) 50 (step S190). Thereby, this process is completed.

  When the secondary user networks 20 and 30 proposed to be reconfigured in step S200 have completed the reconfiguration, the process returns to step S120, and the subsequent processes are executed.

  According to the above-described processing, when a spectrum that is not used in the primary user network 10 (that is, a spectrum opportunity or a spectrum hole) is specified, the two secondary user networks 20 and 30 are specified. Can coexist in the existing spectrum hall. In other words, the coexistence manager (CM) 50 functions to protect the primary user network 10 (that is, to prevent interference) by managing the coexistence of the secondary user networks 20 and 30 at least. .

  Further, according to the above-described processing, the second secondary user network 30 is managed so that interference does not occur in the first secondary user network 20. As a result, the coexistence of a plurality of networks can be ensured. Further, according to the above-described processing, when both the first network 20 and the second network 30 have the possibility of using the spectrum, the coexistence manager (CM) 50 belonging to both networks may interfere with the primary user. If there is a possibility of interference, the coexistence manager (CM) 50 will inform the devices belonging to the first network 20 and the second network 30 about reconfiguration proposals (control messages, parameters, and rules). Send. As a result, interference with the primary user can be reliably suppressed.

  The above-described processing is only an example when the coexistence manager (CM) 50 manages the networks 20 and 30 for secondary users. The above-described processing can be applied in a situation where there are a plurality of secondary user networks. Further, the coexistence manager (CM) 50 may be configured to be able to use different algorithms (programs), or may be configured to be able to perform the above-described processing using a plurality of algorithms (programs). Good.

  Subsequently, an embodiment of the present invention will be described.

  This embodiment corresponds to a case where wireless technology is applied in a rural area. In rural areas, Internet access is provided to households in rural areas by a long-distance regional area network (RAN). Here, the Internet access is performed through a base station (base station) and a customer premises equipment (CPE) using, for example, a television white space.

  The service related to the Internet access as described above can be realized, for example, by complying with the IEEE 802.22 television white space (TV WS) standard.

  On the other hand, in each home, wireless access in the home is realized by a wireless local area network (WLAN), and an ad hoc network using a white space for television is thereby formed. .

  Therefore, the two types of wireless services use the same television white space, which may cause interference. When interference occurs, the throughput of the two types of systems (networks) decreases, and as a result, the user cannot satisfy the performance.

  Therefore, in this embodiment, a coexistence manager (CM) is installed as an independent device at a position where the two types of wireless services as described above exist. The coexistence manager (CM) may be provided in a WLAN access point or in a customer premises facility (CPE).

  Then, the coexistence manager (CM) obtains information from both wireless networks, such as information on spectrum usage, information on service types, and information on quality of service (QoS). In addition, the coexistence manager (CM) accesses the database to obtain information on the geographical position of the secondary user, information on the primary user's geographical position, information on the propagation environment, and the like. Then, the coexistence manager (CM) estimates the numerical values related to the interference of each network by using the obtained information and sends information indicating that the reconfiguration is proposed to both networks. Reconfiguration is performed by adjusting parameters such as transmit power, modulation, data rate, quality of service (QoS), etc. for both networks. In the adjustment, it is necessary to allow both networks to coexist without interfering with each other. For this purpose, the coexistence manager (CM) sets control messages, parameters, and rules. As described above, the user can receive services from both networks at the same time.

  In the present invention, when a wireless network (first network) is set up to use a television white space, another service uses the same frequency band to set up another network (second network). It is effective when trying. In such a situation, the coexistence manager (CM) of the second network first communicates with the coexistence manager (CM) of the device belonging to the first network to obtain information on the spectrum usage status. Note that communication between coexistence managers (CMs) is realized by using a dedicated channel or by using a method using a beacon. Subsequently, the device belonging to the second network identifies an unused spectrum and transmits a pilot signal using the identified spectrum. Thereafter, each coexistence manager (CM) of the device belonging to the first network will notify the coexistence manager (CM) of the device belonging to the second network when interference in the first network is detected. To notify. On the other hand, if no interference is detected, the coexistence manager (CM) belonging to both networks confirms a database in which information of the primary user (for example, a television wireless receiver) is stored.

  In a preferred embodiment, a plurality of coexistence managers (CMs) are installed in a distributed manner in the wireless communication system. For example, a coexistence manager (CM) is installed in each wireless communication device. As a result, all of the wireless communication devices have a coexistence manager (CM) function. In another example, as shown in FIGS. 8 to 60, a coexistence manager (CM) may be installed in each base station (or access point) of the secondary user network. In the example shown in FIG. 8, the coexistence manager (CM) provides an access service to a secondary user network and devices belonging to the network, and sends commands and messages. In the example shown in FIG. 9, two coexistence managers (CMs) exchange information, so that each coexistence manager (CM) can perform a determination process necessary for coexistence. In the example shown in FIG. 60, one coexistence manager (CM) sets information collection and coexistence rules, and supplies the information to the other coexistence manager (CM). The coexistence manager (CM) that receives the information performs a decision process necessary for coexistence. Each secondary user operates according to the information determined by the determination process. As described above, a plurality of coexistence managers (CMs) may have a plurality of functions of one coexistence manager (CM) in a distributed manner. Therefore, the example shown in FIG. 60 is only an example, and the functions of the coexistence manager (CM) may be distributed by other methods.

  In the above-described aspect, the coexistence manager (CM) is configured to be able to adjust parameters and the like so that two secondary user networks can coexist. In this embodiment, a simulation was performed when a time slot was assigned to each secondary user in the case where two secondary users use a spectrum hall in a time division manner.

FIG. 11 is a graph showing the simulation results obtained in the example of the present invention. Here, the horizontal axis in FIG. 11 corresponds to the time slot t ₁ assigned to one secondary user (first secondary user) when the time to use the spectrum hall is ₁ . The time slot t ₂ assigned to the other secondary user (second secondary user) may be obtained by subtracting t ₁ from ₁ (that is, t ₂ = 1−t ₁ ). The vertical axis in FIG. 11 indicates the value of coexistence quality (QoS). In FIG. 11, curve A corresponds to the case where the transmission outputs of the two secondary users are both 1, and curve B sets the transmission output of the first secondary user to 0.5. This corresponds to the case where the transmission output of one secondary user (second secondary user) is set to 1.5, and curve C sets the transmission output of the first secondary user to 0.5 and the other secondary user. This corresponds to the case where the transmission output of (secondary secondary user) is 1.5.

It can be seen from FIG. 11 that the coexistence quality (QoS) value varies depending on the assigned time slot and transmission output. Therefore, in a preferred embodiment of the present invention, the coexistence manager (CM) 50 uses the coexistence quality (QoS) value as a performance judgment criterion at the time of coexistence, and adjusts parameters related to transmission output and time slot allocation. Do. As a specific example, the transmission output value of the first secondary user is adjusted to be high so that the coexistence quality value (QoS) is maximized, and the time slot of the second secondary user is lengthened. Adjust as follows. However, the sum of the transmission output value of the first secondary user and the transmission output value of the second secondary user is assumed to be constant. In addition, while adjusting so that the transmission output value of a 2nd secondary user may become high, you may adjust so that the time slot of a 1st secondary user may become long. In this way, parameters and the like can be adjusted after evaluating both the spectrum usage efficiency and the degree of interference with the primary user. Then, the first secondary user and the second secondary user use the spectrum home within the assigned time slot (that is, in a time division manner). Thereby, even if a plurality of networks coexist in the wireless communication system 1, the performance can be improved.

  The present invention can be applied to a wireless communication system and a wireless communication method.

1 wireless communication system 10 primary user network 11 primary user 12 base station 20 first secondary user network 21 first secondary user 22 base station 30 second secondary user network 31 second secondary user 32 base station 40 The database

Claims (3)

The Internet coexistence manager (CM) obtains the sensing information and the Internet coexistence manager (CM) and the transport service access point (T-SAP) from the database connected via the application service access point (A-SAP). An information collecting step of acquiring information about the first secondary user and the second secondary user connected via
The Internet coexistence manager (CM) uses the sensing information collected in the information collecting step, the information about the first secondary user (2, 1), and the first secondary user (2, 1). 1,1) and the second secondary user (2,1) are searched without interference, and the first secondary user (1,1) and the second secondary user (2,1) are not interfered. If an available spectrum is found, determine the spectrum, and if no usable spectrum is found without interference to the first secondary user (1,1) and the second secondary user (2,1) Returning to the information collecting step, acquiring information again, and based on the newly acquired information The constant, and the determining step,
A determination transmission step in which the Internet coexistence manager (CM) transmits information on the determined spectrum to the first secondary user (1,1) and the second secondary user (2,1);
including,
Spectrum processing method in cognitive radio.   The method of claim 1, wherein the sensing information includes information regarding a currently available channel. The information about the first secondary user (1,1) and the second secondary user (2,1) is the position of the first secondary user (1,1) and the second secondary user (2,1). The method of claim 1, comprising information regarding.

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