KR20170000775A - Method and apparatus for random access with access time distribution scheme - Google Patents

Abstract

Disclosed are a method and an apparatus for a random access by using an access time distribution scheme. A terminal generates a random number for a random access and compares frame information transmitted from a base station with the generated random number. When the frame information matches the random number, a preamble for the random access is transmitted to the base station.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a random access method and a random access method using the access time dispersion method,

The present invention relates to a random access method, and more particularly, to a random access method and apparatus using a connection time dispersion method in a mobile communication network.

Machine-to-machine (M2M) communication is a process of communication between machines in order to perform various operations such as sensing, processing, decision making, acting on decisions, . ≪ / RTI > The biggest difference between M2M communication and human-to-human communication (H2H) is that human control is reduced in the communication life cycle.

However, due to the increasing automation, many new applications have emerged that use M2M technology, which has caused the explosion of the number of devices (terminals) that are equipped with M2M technology. In addition, the management of massive connectivity (MC) to satisfy the QoS requirements of various applications running on these devices has become an important issue.

Therefore, when the number of devices attempting to access the network at the same time is larger than the amount of available radio resources, an overload occurs and the probability of failure of the network connection increases. Therefore, a method for solving this problem is required.

SUMMARY OF THE INVENTION The present invention provides a random access method and apparatus for preventing collision in a mobile communication network.

A method according to an aspect of the present invention includes: generating a random number for random access in a terminal random access method in a mobile communication system; Comparing frame information transmitted from the base station with the generated random number; And transmitting a preamble for random access to the base station if the frame information matches the random number.

The step of generating the random number may use the information uniquely assigned to the terminal as a seed value and generate the random number using the seed value. The seed value may be an International Mobile Subscriber Identity (IMSI) assigned to the UE. The seed value may be an International Mobile Equipment Identity (IMEI) assigned to the UE. The seed value may be an MSIN (Mobile Subscriber Identification Number) allocated to the UE.

Meanwhile, the frame information may be a serial frame number (SFN).

Wherein generating the random number comprises: generating a first random number for random access; And generating a second random number for random access, the comparing comprising: comparing the first frame information transmitted from the base station with the first random number; And comparing the second frame information transmitted from the base station with the second random number when the first frame information and the first random number coincide with each other.

The transmitting the preamble to the base station may transmit a preamble for random access to the base station when the second frame information matches the second random number.

The first frame information may be a serial frame number (SFN), and the second frame information may be a sub-frame number (sfn).

The first random number may be any value included in the first range, the second random number may be any value included in the second range, and the first range and the second range may be different.

The minimum value and the maximum value of the first range may correspond to the minimum value and the maximum value of the SFN, respectively, and the minimum value and the maximum value of the second range may correspond to the minimum value and the maximum value of the sfn, respectively.

The method may further include setting the seed value before the step of generating the random number. In this case, the step of setting the seed value may include a first method in which a seed value is set at the time of terminal registration, a second method in which a seed value is set at the time of terminal installation, You can set the seed value based on one of the three methods. Priorities are given to the first method, the second method and the third method, and the seed value can be set based on the corresponding method according to the priority.

An apparatus according to another aspect of the present invention includes: a random access device in a mobile communication system, an RF converter for transmitting and receiving signals through an antenna, and a processor connected to the RF converter and performing random access, A random number generator for generating a random number for random access; A comparing unit comparing the frame information transmitted from the base station with the generated random number; And an access processor for transmitting a preamble for random access to the base station when the frame information matches the random number.

The random number generator comprising: a first random number generator for generating a first random number for random access; And a second random number generator for generating a second random number for random access.

Wherein the comparison unit compares the first frame information transmitted from the base station with the first random number and if the first frame information matches the first random number, The access processing unit may be configured to transmit a preamble for random access to the base station when the second frame information matches the second random number.

The first frame information may be a serial frame number (SFN), and the second frame information may be a sub-frame number (sfn). The first random number may be any value included in the first range, the second random number may be any value included in the second range, and the first range and the second range may be different. The minimum value and the maximum value of the first range correspond to the minimum value and the maximum value of the SFN, respectively, and the minimum value and the maximum value of the second range may correspond to the minimum value and the maximum value of the sfn, respectively.

Wherein the random number generator uses the information uniquely assigned to the terminal as a seed value and generates the random number using the seed value, wherein the seed value is an International Mobile Subscriber Identity (IMSI) ), An International Mobile Equipment Identity (IMEI), and a Mobile Subscriber Identification Number (MSIN).

The seed value may be one of a first method of setting a seed value at the time of terminal registration, a second method of setting a seed value at the time of terminal installation, and a third method of setting a seed value at terminal connection cancellation Can be set.

According to the embodiment of the present invention, the timing at which a plurality of terminals try to connect is different from each other, so that a collision due to an overload in a random access can be prevented.

Also, by generating a random number having uniform distribution with each terminal having a uniform distribution according to the connection time distribution scheme, the connection of the terminals is changed from the burd distribution to the uniform distribution, .

In addition, it is possible to reduce the collision probability by dividing the connection of the terminals into 1024 SFN time intervals to induce the connection, and at the same time, it is possible to group and control the terminals in the network into 1024 groups. In addition, the probability of collision can be further reduced by additionally connecting the terminals by dividing the connection of the terminals into 10 sfn time intervals.

1 is an exemplary diagram illustrating a network environment in which a RACH preamble conflict occurs.
2 is a diagram illustrating a process of performing random access using a connection time dispersion scheme according to an embodiment of the present invention.
3 is a flowchart of a random access method according to an embodiment of the present invention.
4 is a structural diagram of a random access apparatus according to an embodiment of the present invention.
5 is a diagram illustrating a random access procedure using a connection time dispersion scheme according to another embodiment of the present invention.
6 is a flowchart of a random access method according to another embodiment of the present invention.
7 is a structural diagram of a random access apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Throughout the specification, a terminal is referred to as a device, a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station , An HR-MS, a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE) Device, MT, MS, AMS, HR-MS, SS, PSS, AT, UE and the like.

Also, a base station (BS) is an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station (HR) A femto BS, a home Node B, a home eNodeB, a pico BS, a metro BS, a micro BS, a base station BS, ), Etc., and may be all or part of an ABS, a Node B, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, an RS, an RN, an ARS, It may include a negative feature.

Hereinafter, a random access method and apparatus using a connection time dispersion method according to an embodiment of the present invention will be described with reference to the drawings.

In a mobile communication system, in the case of Random Access (hereinafter referred to as RA), a terminal initially uses four messages to access the network. These four messages can be called ARP (Access Reservation Protocol) have.

The first message is a preamble signal for RA and can be named "RAP (Random Access Preamble) (Msg1) ". For example, one of the 64 available RACH preambles that constitute one radio resource for the RA is selected and transmitted to the base station. The second message is the RA response signal, which may be named "RAR (Random Access Response) (Msg2) ". When the base station receives the RAP, the RPA responds to the terminal with the RAR corresponding to the RA resource including the time and frequency at which the RPA is received. At this time, the base station transmits another ID, also called a temporary C-RNTI (Cell Radio Network Temporary Identity), i.e., a temporary cell identifier, to the UE. If the UE can not receive the RAR for a certain time after transmitting the RAP, the UE increments the counter, and after power ramping, transmits the RAP again.

The third message is a Radio Resource Control (RRC) Connection Request (Msg3), and the UE transmits an RRC connection request message to the BS. At this time, the UE uses the temporary C-RNTI, which is a temporary cell identifier allocated from the BS in the previous step. The fourth message is an RRC Connection Setup message (Msg4), and the BS replies a contention resolution message to the MS. This message includes a new cell identifier, i.e., a C-RNTI.

In this way, when a terminal accesses a network, a collision may occur when two or more UEs simultaneously transmit the same RACH preamble (Msg1). For example, when two or more UEs transmit the same RACH preamble at the same time (Msg1), the base station transmits RAR (Msg2), at this time, attempts to access the same temporary C-RNTI and uplink grant Lt; / RTI > The MSs transmit Layer-2 and Layer-3 (L2 / L3) messages to the BS through the same resource allocation (Msg3). These messages transmitted through the same resource allocation may interfere with each other, and the base station may not be able to decode all of the messages from the terminals. In this case, the terminals that have not received the collision solving message (Msg4) from the base station retry the connection attempt after a predetermined time.

1 is an exemplary diagram illustrating a network environment in which a RACH preamble conflict occurs.

The terminal 1 101, the terminal 2 102, the terminal 3 103 and the base station 104 may be arranged in the network 100 as shown in FIG. In this network environment, when the terminals 101, 102, and 103 in the network 100 simultaneously attempt to access the network 100, each terminal randomly selects one of up to 64 RACH preambles, (104). For example, the first terminal 101 transmits RACH preamble 1 (RAP1) to the base station 104, the second terminal 102 transmits the RACH preamble 2 (RAP2) to the base station 104, Transmits the RACH preamble 3 (RAP3) to the base station 104. [

At this time, if the RACH preambles RAP1, RAP2, and RAP3 transmitted from the UEs 101, 102, and 103 have the same value, a collision occurs. When a collision occurs, the base station 104 can not decode the messages of the UEs, and the UEs 101, 102, and 103 must retry the random access. Since only a maximum of 64 RACH preambles can be used in the mobile communication network, the greater the number of terminals simultaneously attempting random access, the higher the probability of collision.

In the embodiment of the present invention, the collision probability generated by the random access is reduced using the connection time dispersion scheme.

2 is a diagram illustrating a process of performing random access using a connection time dispersion scheme according to an embodiment of the present invention.

The terminal 1 201, the terminal 2 202, and the base station 203 may be disposed in the network 200, as shown in FIG. When the UEs 201 and 202 desire to access the Node B 203 in this network environment, each of the UEs 201 and 202 uses a Pseudo-Random Number Generator .

The random number generator uses a seed value to generate a random number. The seed value used for the random number generation is unique for each terminal. As the seed value, for example, an International Mobile Subscriber Identity (IMSI) assigned to each mobile station may be used. Since the IMSI is composed of MCC (Mobile Country Code), MNC (Mobile Network Code), and MSIN (Mobile Subscriber Identification Number), it can not coincide with IMSI values assigned to other terminals as unique values.

In addition, the minimum value and the maximum value can be set for the random number. For example, a minimum value of SFN (system frame number) of 0 is applied as a minimum value of a random number generated by a random number generator, and a maximum value of SFN of 1023 is applied as a maximum value of a random number. Therefore, the random number generated by the random number generator is an arbitrary value between 0 and 1023.

For example, assume that the random number generated in terminal 1 (201) is 205 and the random number generated in terminal 2 (202) is 710. Each of the UEs 201 and 202 monitors SFN which is a frame index number of a radio frame currently provided by the Node B 203 and transmits a RACH preamble when the SFN and the random number generated by the SFN match. Specifically, when the SFN becomes 205 (FN1), the current SFN matches with the random number generated in the first terminal 201, so that the first terminal 201 transmits a message including the RACH preamble 1 (RAP1) to the base station 203 do. When the SFN becomes 710 (FN2) after a predetermined time and the current SFN matches the random number generated in the second terminal 202, the second terminal 202 transmits a message including the RACH preamble 2 (RAP2) to the base station 203 send.

Since the timing at which the terminal 1 (201) and the terminal 2 (202) attempt random access differ from each other at the time (FN1) at which the SFN is 205 and at the time (FN2) at which the SFN is 710, Does not occur.

3 is a flowchart of a random access method according to an embodiment of the present invention.

As shown in the attached FIG. 3, the random access device uses the seed value to generate a random number included in the first range. For example, the random access device generates an arbitrary value between 0 and 1023 as a random number (N1) using the IMSI assigned to the terminal as a seed value (SlOO). The random access unit 1 monitors the SFN information provided by the base station and compares the random number N1 generated in the previous step S100 with the current SFN (S110).

If the random number N1 does not coincide with the SFN, the random access unit 1 continuously monitors the SFN. If the random number N1 matches the SFN, the random access unit 1 attempts random access to the base station (S120).

4 is a structural diagram of a random access apparatus according to an embodiment of the present invention.

The random access device 1 according to the embodiment of the present invention includes a processor 11, a memory 12 and a radio frequency (RF) converter 13, as shown in FIG. The processor 11 may be configured to implement the methods described above based on Figures 2 and 3.

To this end, the processor 11 includes a random number generator 111, a monitoring unit 112, a comparison unit 113, and an access processing unit 114.

The random number generator 111 generates a random number for the access distribution scheme based on the seed value. The random number is an arbitrary value included in the first range including the minimum value and the maximum value.

The monitoring unit 112 monitors the SFN, which is the frame index number of a radio frame currently provided by the base station, and the comparing unit 113 compares the monitored current SFN with the random number generated by the random number generator 111.

The access processing unit 114 attempts random access to the base station when the random number matches the SFN.

The memory 12 is connected to the processor 11 and stores various information related to the operation of the processor 11. [ The RF converter 13 is connected to the processor 11 and transmits or receives radio signals.

5 is a diagram illustrating a random access procedure using a connection time dispersion scheme according to another embodiment of the present invention.

The terminal 1 501, the terminal 2 502, and the base station 503 may be disposed in the network 500 as shown in FIG. In this network environment, when the terminals 501 and 502 in the network desire to access the base station 503, each of the terminals 501 and 502 uses a random number generator in the terminal to generate two random Generates a number.

The random number generator generates a random number by using the seed value. The seed value is a unique value that differs from terminal to terminal, and as described above, it may be an IMSI assigned to each terminal.

Unlike the above embodiment, the random number generator uses the seed value to generate two random numbers. A first random number is generated by generating a first random number. As the minimum value and the maximum value of the first random number, for example, a minimum value of SFN of 0 and a maximum value of 1023 may be applied, respectively. Thus, the first random number generated in the random number generator may be any value between 0 and 1023. Also, a second random number is generated through a second random number generation. For example, a minimum value of sfn (sub-frame number) of 0 and a maximum value of 9 may be applied to the minimum and maximum values of the second random number, respectively. Thus, the second random number generated in the random number generator may be any value between zero and nine. The first random number and the second random number thus have different minimum and maximum values.

5, the first random number generated by the terminal 1 (501) is 205, the second random number is 2, the first random number generated by the terminal 2 (502) is 205 and the second random number Let's assume 6 is. In this case, each of the UEs 501 and 502 monitors SFN, which is a frame index number of a radio frame provided by the current BS 503. When the SFN becomes 205 (FN11), the current SFN matches the first random number generated in the terminal 1 (501) and the terminal 2 (502), so that the terminal 1 (501) And monitors sfn. When sfn becomes 2 (FN21) in the current frame, the current sfn matches the second random number generated in the first mobile station 501, so that the first mobile station 501 transmits a message including the RACH preamble 1 (RAP1) . The mobile station 502 transmits a message including the RACH preamble 2 (RAP2) to the base station 502 (502) because the current sfn is equal to the second random number generated in the second mobile station 502 . The timing at which random access is attempted in the terminal 1 (501) and the terminal 2 (502) are different from each other at a time point (FN21) where sfn is 2 and a time point (FN22) where sfn is 6, so that even if the same RACH preamble is used, Does not occur.

6 is a flowchart of a random access method according to another embodiment of the present invention.

As shown in Fig. 6, the random access device generates a plurality of random numbers using the seed value. Specifically, the random access device generates an arbitrary value between 0 and 1023 as a first random number (N1) using the IMSI assigned to the terminal as a seed value (S300). Also, an arbitrary value between 0 and 9 is generated as a second random number (N2) using the IMSI allocated to the terminal as a seed value (S310).

The random access device 1 monitors the SFN information provided by the current base station and compares the SFN with the first random number N1 generated in the previous step S300 at step S320. If the first random number N1 and the SFN do not coincide with each other, continuous monitoring is performed. If the first random number N1 matches the SFN, the sfn information provided by the base station is monitored, The random number N2 is compared with sfn (S330).

If the second random number N2 does not coincide with the sfn, continuous monitoring is performed. If the second random number N2 matches the sfn, random access to the base station is attempted at step S340.

7 is a structural diagram of a random access apparatus according to another embodiment of the present invention.

A random access device 1 according to another embodiment of the present invention includes a processor 11, a memory 12 and a radio frequency (RF) converter 13, as shown in FIG. The processor 11 may be configured to implement the methods described above with reference to Figures 5 and 6 above.

The processor 11 includes first and second random number generators 111a and 111b, a monitoring unit 112, a comparison unit 113, and an access processing unit 114. [

The first random number generator 111a generates a first random number for the access distribution method based on the seed value. The first random number is an arbitrary value included in the first range consisting of the minimum value and the maximum value. The second random number generator 111b generates a second random number for the access distribution scheme based on the seed value. The second random number is an arbitrary value included in the second range consisting of the minimum value and the maximum value. Here, the first range and the second range may be different from each other, and the seed value used in generating the first random number may be different from the seed value used in generating the second random number.

On the other hand, in some cases, the first random number generator 111a and the second random number generator 111b may be constituted by one random number generator, and one random number generator may generate a random number May be adjusted to generate the first random number N1 and the second random number N2, respectively.

The monitoring unit 112 monitors the SFN, which is the frame index number of the radio frame currently provided by the base station, and monitors the subframe index number sfn of the radio frame currently provided by the base station.

The comparing unit 113 compares the monitored current SFN with the first random number generated by the first random number generator 111a and also compares the monitored current SFN with the second random number generated by the second random number generator 111b Compare the random numbers.

The access processing unit 1114 attempts random access to the base station when the first random number matches the SFN and the second random number matches the sfn.

The memory 12 is connected to the processor 11 and stores various information related to the operation of the processor 11. [ The RF converter 13 is connected to the processor 11 and transmits or receives radio signals.

In the embodiments of the present invention as described above, the seed value used for the random number generation is a unique value which is different from terminal to terminal, and instead of IMSI, International Mobile Equipment Identity (IMEI) can be used as a seed value. Since the IMEI is composed of TAC (Type Allocation Code), SNR (Serial Number) and CD (Check Digit), it is unique and does not match the values assigned to other terminals.

In addition, MSIN (Mobile Subscriber Identification Number) may be used instead of IMSI as a seed value used for random number generation. The MSIN is unique in the Public Land Mobile Network (PLMN) and does not match the values assigned to other terminals.

On the other hand, in order to control the random access, the seed value can be set at the time of terminal registration. In addition, the seed value can be set through the following method.

Method 1. How to acquire or set the seed value when installing the terminal.

Method 2. A method of acquiring or setting a seed value at terminal disconnection.

A method of acquiring or setting a seed value at the time of installing a terminal is a method of setting a seed value as an initial value in the terminal at the time of installing the terminal.

A method of acquiring or setting a seed value at the time of terminal disconnection is a method of acquiring a seed value as an initial value to be used at a time point when the terminal is reconnected from the base station at the time when the terminal is disconnected.

As described above, priority can be given to methods for setting the seed value (setting at the time of registration, setting at the time of installation, setting of connection and presentation), and the seed value can be set using the corresponding method in accordance with the priority have. Also, the priority applied to each method may be changed depending on the situation, or may be operated in a selective combination manner.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (20)

In a terminal random access method in a mobile communication system,
Generating a random number for random access;
Comparing frame information transmitted from the base station with the generated random number; And
And transmitting a preamble for random access to the base station if the frame information matches the random number
/ RTI > The method according to claim 1,
Wherein the step of generating the random number uses the information uniquely assigned to the terminal as a seed value and generates the random number using the seed value. The method according to claim 2, wherein
Wherein the seed value is an International Mobile Subscriber Identity (IMSI) assigned to a terminal. The method according to claim 2, wherein
Wherein the seed value is an International Mobile Equipment Identity (IMEI) assigned to a terminal. The method according to claim 2, wherein
Wherein the seed value is a Mobile Subscriber Identification Number (MSIN) assigned to a terminal. The method according to any one of claims 1 to 5, wherein
Wherein the frame information is a serial frame number (SFN). The method of claim 1, wherein
Wherein generating the random number comprises:
Generating a first random number for random access; And
Generating a second random number for random access
Lt; / RTI >
Wherein the comparing comprises:
Comparing the first frame information transmitted from the base station with the first random number; And
Comparing the second frame information transmitted from the base station with the second random number if the first frame information and the first random number match,
/ RTI > The method of claim 7, wherein
Wherein the step of transmitting the preamble to the base station transmits a preamble for random access to the base station if the second frame information matches the second random number. The method of claim 7, wherein
Wherein the first frame information is a serial frame number (SFN) and the second frame information is a sub-frame number (sfn). The method of claim 9, wherein
Wherein the first random number is any value included in the first range and the second random number is any value included in the second range and wherein the first range and the second range are different. The method of claim 10, wherein
Wherein a minimum value and a maximum value of the first range correspond to a minimum value and a maximum value of the SFN, respectively, and a minimum value and a maximum value of the second range correspond to a minimum value and a maximum value of the sfn, respectively. The method according to claim 2, wherein
Before the step of generating the random number
Setting the seed value
Further comprising:
The step of setting the seed value comprises:
A seed value is set based on a first method of setting a seed value at the time of terminal registration, a second method of setting a seed value at the time of installing the terminal, and a third method of setting a seed value at the time of terminal disconnection / RTI > The method of claim 12, wherein
Wherein a priority is given to the first method, the second method and the third method, and a seed value is set based on a corresponding method in accordance with a priority order. In a random access device in a mobile communication system,
An RF converter for transmitting and receiving signals through an antenna, and
A processor coupled to the RF transducer and performing random access,
The processor comprising:
A random number generator for generating a random number for random access;
A comparing unit comparing the frame information transmitted from the base station with the generated random number; And
An access processing unit for transmitting a preamble for random access to the base station when the frame information matches the random number,
And a random access device. The method of claim 14, wherein
The random number generator
A first random number generator for generating a first random number for random access; And
A second random number generator for generating a second random number for random access,
And a random access device. The method of claim 15, wherein
Wherein,
Comparing the first frame information transmitted from the base station with the first random number and comparing the second frame information transmitted from the base station with the second random number if the first frame information matches the first random number, , ≪ / RTI >
Wherein the access processing unit is configured to transmit a preamble for random access to the base station when the second frame information matches the second random number. The method of claim 16, wherein
Wherein the first frame information is a serial frame number (SFN) and the second frame information is a sub-frame number (sfn). The method of claim 17, wherein
The first random number is an arbitrary value included in the first range, the second random number is an arbitrary value included in the second range, the first range and the second range are different from each other,
Wherein a minimum value and a maximum value of the first range correspond to a minimum value and a maximum value of the SFN, respectively, and a minimum value and a maximum value of the second range correspond to a minimum value and a maximum value of the sfn, respectively. The method of claim 14, wherein
The random number generator uses information uniquely assigned to the terminal as a seed value and generates the random number using the seed value,
Wherein the seed value is one of an International Mobile Subscriber Identity (IMSI), an International Mobile Equipment Identity (IMEI), and a Mobile Subscriber Identification Number (MSIN). The method of claim 19, wherein
The seed value may be one of a first method of setting a seed value at the time of terminal registration, a second method of setting a seed value at the time of terminal installation, and a third method of setting a seed value at terminal connection cancellation Based random access device.

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