JP2011509587A - Resource request and allocation method using CDMA code in wireless access communication system based on multi-hop orthogonal frequency division multiple access - Google Patents

Abstract

A resource and allocation method in a wireless access communication system based on multi-hop orthogonal frequency division multiple access (OFDMA) with multiple terminals, relay stations and base stations is disclosed. The method includes a step in which the plurality of terminals request the relay station to allocate resources, a step in which the relay station grasps the number of the plurality of terminals, and the relay station transmits the plurality of terminals to the base station. Requesting resource allocation to a plurality of terminals, the base station allocating resources to the plurality of terminals collectively, and the relay station being allocated to the plurality of terminals collectively. Allocating resources to each terminal.

Description

  The present invention relates to a resource request and allocation using a CDMA code (Code Division Multiplexing Access code) in a radio access communication system based on Orthogonal Frequency Division Multiplexing Access (OFDMA) employing a multihop relay system. Regarding the method. In particular, the present invention relates to a method in which a terminal connected to a relay station requests and allocates resources using a CDMA code.

  A method for requesting resources in a MAC (media access control) layer of a wireless access communication system based on OFDMA includes a resource request method using a bandwidth request header, a resource request method using piggy back, And a resource request method using a CDMA code.

  The resource request method using the bandwidth request header is a method in which when there is an uplink allocation, the terminal uses the remaining resources to request further necessary resources through the bandwidth request header. is there. This request is made for each connection identifier (CID) of the terminal, but necessary resources are requested for each service of the terminal.

  The resource request method using piggyback is a method for requesting a desired resource through a piggyback request field of a grant management subheader.

  The resource request method using a CDMA code is a method in which a terminal requests a resource through CDMA code transmission using a specific ranging channel. At this time, a CDMA code to be used is arbitrarily selected from a code set for bandwidth request. A terminal that wants to receive resource allocation transmits a CDMA code to the base station. The base station that has received the CDMA code allocates resources to the terminal that has transmitted the CDMA code via a CDMA allocation message (CDMA allocation IE). However, this CDMA allocation message includes broadcast connection identifier information instead of the terminal connection identifier (basic CID), and also includes CDMA code information used by the terminal. Therefore, all the terminals that have sent the CDMA code receive all the CDMA assignment messages transmitted from the base station, and whether or not the CDMA code included in the CDMA assignment message matches the CDMA code sent by itself. If they match, the resource allocated to the CDMA allocation message is used. If a CDMA code is sent but no resource allocation is made, it is assumed that a CDMA code collision has occurred, and a new CDMA code is transmitted through a secondary exponential backoff process.

  The wireless access communication system based on the above-described single-hop orthogonal frequency division multiple access has recently been proposed with a technique in which the service area is expanded by using a multi-hop technique due to a very narrow service area.

  In the case of a radio access communication system based on such multi-hop orthogonal frequency division multiple access, as shown in FIG. 1, a base station BS and a terminal MS2 communicate via a relay station RS (relay station).

  When a resource request method using a CDMA code is applied to a radio access communication system based on such multi-hop orthogonal frequency division multiple access, the terminal MS2 communicating with the relay station RS transmits the CDMA code to the relay station RS. And request resources. Then, relay station RS relays the CDMA code of the resource requesting terminal to base station BS using the ranging channel. However, when relaying in this way, the base station BS distinguishes whether the CDMA code is directly received from a communicable terminal MS1 or received via the relay station RS. Can not do it. The reason is that CDMA has no information for the terminal. Therefore, there is a problem that the base station BS cannot correctly allocate resources to the terminal that has transmitted the CDMA code.

  The present invention is to solve the problems of the prior art, and an object of the present invention is to request and allocate resources using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access. It is to provide a method.

  In order to achieve the above object, a resource request and allocation method in a radio access communication system based on a multi-hop orthogonal frequency division multiple access comprising a plurality of terminals, relay stations, and base stations according to the present invention comprises A first stage in which the terminal requests resource allocation to the relay station, a second stage in which the relay station grasps the number of the multiple terminals, and the relay station determines the number of the multiple terminals in the base station. A third stage for requesting information and resource allocation to the multiple terminals; a fourth stage in which the base station collectively allocates resources to the multiple terminals; and the relay station collectively to the multiple terminals. And a fifth step of allocating resources allocated to each terminal.

  Further, the resource request and allocation method in the relay station of the wireless access communication system based on the multi-hop orthogonal frequency division multiplex connection including a plurality of terminals, a relay station, and a base station according to the present invention is the plurality of terminals. When a resource allocation is requested from the first stage, a first stage of grasping the number of the plurality of terminals, and a second stage of requesting the base station to count the number of terminals and to allocate resources to the plurality of terminals. And when a resource is collectively allocated from the base station to the large number of terminals, a third step of allocating the resources collectively allocated to the large number of terminals to each terminal.

  Also, the resource request and allocation method in the base station of the wireless access communication system based on multi-hop orthogonal frequency division multiple access comprising a number of terminals, relay stations, and base stations according to the present invention is from the relay station. Information on the number of terminals that requested resource allocation to the relay station, a first stage in which resource allocation is requested to the terminals, and whether or not resource allocation to the terminals is possible. And a third step of allocating resources to the plurality of terminals collectively through the relay station.

  According to the present invention, since the relay station collects resource requests of a large number of terminals and requests resource allocation to the base station by a message, the signaling overhead due to the resource request can be reduced. Management can be performed efficiently, and the resources allocated from the base station can be adjusted and allocated to each terminal by the relay station. Therefore, resources can be allocated appropriately in consideration of the priority and service quality of the terminals. There is an advantage that you can.

It is a figure which shows the radio | wireless access communication system based on a multihop orthogonal frequency division multiple connection. 3 is a flowchart illustrating a process in which a terminal requests resources using a CDMA code according to the present invention. 3 is a signal flow diagram illustrating a resource request and allocation process using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention. 3 is a flowchart illustrating an operation in a relay station for requesting and allocating resources using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention. 3 is a flowchart illustrating an operation in a base station for requesting and allocating resources using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention.

  According to the present invention, a relay station collects resource requests for terminals under its jurisdiction and informs the base station of the number of terminals that have requested resources, and the base station receiving the resource request is required in the relay station area. System resources are allocated all at once, and the relay station allocates resources to terminals, thereby maximizing system performance.

  Hereinafter, a resource request and allocation method using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a radio access communication system based on multi-hop orthogonal frequency division multiple access.
In a radio access communication system based on multi-hop orthogonal frequency division multiple access, the relay station RS is located between the base station BS and the terminal MS2 to serve the terminal MS2 far from the base station BS, The data transmitted by the base station BS is relayed to the terminal MS2 to reduce path loss. At this time, since the terminal MS2 receiving the service from the relay station RS cannot directly communicate with the base station BS due to transmission power restrictions, the relay station RS must be set when transmitting / receiving data to / from the base station BS. Have to go through. All data and control information transmitted from the relay station RS to the terminal MS2 are received from the base station BS and transmitted. That is, the authority that can control the terminal registered in the relay station RS exists only in the base station BS, and the relay station RS only plays a role of relaying the control signal of the base station BS.

  The terminal MS2 cannot distinguish between the relay station RS and the base station BS, and operates by recognizing the relay station RS as the base station BS even if it is registered in the relay station RS. When communicating with a terminal registered in the relay station RS, the relay station RS operates like the base station BS, transmits and receives necessary control information and data to the terminal MS2, and relays it to the base station BS. At this time, the generated control information is generated from the base station BS to which the relay station RS belongs and is transmitted to the terminal MS2 via the relay station RS. In addition, the relay station RS operates in the same manner as a terminal to perform communication with the base station BS, but receives resource allocation from the base station BS and uses the allocated resource to register information on the terminal registered in itself. To the base station BS. However, the base station BS can classify the terminal and the relay station RS by a method such as classification of the connection identifier CID.

FIG. 2 is a flowchart illustrating a process in which a terminal requests a resource using a CDMA code according to the present invention, which is the same as the conventional operation.
First, if uplink resources are required (S21), the terminal transmits a CDMA code to the base station via the ranging channel (S22). When a CDMA allocation message is received from the base station (S23), it is confirmed whether or not the CDMA code in the received CDMA allocation message matches its own CDMA code (S24). As a result of the confirmation, if the received CDMA code matches the own CDMA code, the resources allocated to the received CDMA assignment message are used (S25), and the received CDMA code matches the own CDMA code. If not, a new CDMA code is selected after the second exponential backoff process (S26), and the process returns to step S22 to transmit the new CDMA code.

  FIG. 3 is a signal flow diagram illustrating a resource request and allocation process using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention.

First, it is assumed that the terminals MS1 and MS2 are terminals that communicate with the base station BS via the relay station RS.
The terminals MS1 and MS2 that need uplink resources transmit CDMA codes to the relay station RS (S31). The terminal MS1 and the terminal MS2 transmit a CDMA code when uplink resources are required, whether it is the relay station RS or the base station BS.

  The relay station RS that has received the CDMA code from many terminals MS1 and MS2 knows the number of terminals that have transmitted the CDMA code (S32). Thereafter, the relay station RS transmits its CDMA code to the base station BS via the ranging channel (S33). When the CDMA allocation message is received from the base station BS (S34), the relay station RS transmits a bandwidth request header to the base station BS (S35). The base station BS receiving the bandwidth request header transmits an uplink MAP (Up Link MAP) to the relay station RS (S36), and the relay station RS uses the resources included in the uplink MAP received in step S36. A multi-hop relay code report message (MR_Code-REP message) is transmitted to the base station BS (S37). This multi-hop relay code report message includes information on the number of terminals that have transmitted a CDMA code to the relay station RS.

  The base station BS that has received the multi-hop relay code report message transmits the uplink MAP to the relay station RS (S38), and the relay station RS adds each terminal MS1, MS2 to the CDMA assignment message included in this uplink MAP. The CDMA allocation message to be transmitted to the terminal is completed by adding information on the CDMA code (S39), and the CDMA allocation message is transmitted to the terminals MS1 and MS2 (S40).

  The base station BS knows the information on the number of terminals that have sent the CDMA code, but does not know the CDMA code transmitted by each of the terminals MS1 and MS2, and therefore allocates resources corresponding to the number of terminals all together to generate an uplink MAP. The relay station RS transmits the CDMA allocation message to each of the terminals MS1 and MS2 by putting the CDMA code information of the terminal in the uplink MAP received from the base station BS.

  FIG. 4 is a flowchart illustrating an operation in a relay station for requesting and allocating resources using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention.

  A CDMA code is received from the terminal (S41). If the received CDMA code is a CDMA code for bandwidth request (S42), the number of terminals that transmitted the CDMA code is grasped (S43). Then, the relay station transmits its CDMA code to the base station (S44), and receives a CDMA assignment message from the base station (S45). The relay station transmits a bandwidth request header to the base station using the resources specified in the CDMA allocation message received in step S45 (S46), and receives an uplink MAP from the base station (S47). After receiving the uplink MAP, the relay station transmits a multi-hop relay code report message (MR_Code-REP message) to the base station using the specified resources (S48). In this multi-hop relay code message, The terminal number information obtained in step S43 is included. The relay station receives the uplink MAP from the base station (S49). The uplink MAP received in step S49 includes a CDMA allocation message to be transmitted to the terminal that has transmitted the CDMA code. The CDMA allocation message included in the uplink MAP includes a terminal-specific CDMA code. Absent. Therefore, the relay station inserts the field value related to the CDMA code into the CDMA allocation message transmitted to the terminal, and then transmits the CDMA allocation message to the terminal (S50).

  The fields related to the CDMA code of the CDMA assignment message, which the relay station must satisfy, are a repetition coding indicator field, a ranging code field, a ranging symbol field ( ranging symbol field) and ranging subchannel field.

  That is, in the radio access communication system based on the conventional multi-hop orthogonal frequency division multiple access, the resource request and allocation for the actual terminal is performed directly at the base station, whereas in the present invention, the base station Rather than at the relay station. That is, the relay station has resource allocation flexibility by delegating resource allocation authority from the base station. If an amount smaller than the requested amount of resources is allocated from the base station, the relay station allocates resources to the terminals in consideration of the order or priority of the terminals that requested the resources. In addition, after a terminal requests a resource, if it moves out of its jurisdiction due to movement, the resource allocated from the base station can be allocated to another terminal, or it can be used directly by itself.

  FIG. 5 is a flowchart illustrating an operation in a base station for requesting and allocating resources using a CDMA code in a wireless access communication system based on multi-hop orthogonal frequency division multiple access according to the present invention.

  The base station allocates resources to a terminal that can directly communicate with itself by a CDMA allocation message directly in the same manner as the conventional method. That is, when the CDMA code is received, the base station determines whether the CDMA code is a code for bandwidth request, and if the received CDMA code is a code for bandwidth request. The uplink resource is allocated through the CDMA allocation message, and the CDMA code of the terminal is inserted into the CDMA allocation message and transmitted.

  On the other hand, the base station receives information on the number of terminals that transmitted the CDMA code to the relay station using a multi-hop relay code report message from the relay station (S51). Then, the base station determines whether there is an assignable uplink resource (S52). As a result of the determination, if there is an uplink resource that can be allocated, the base station inputs a CDMA allocation message to be allocated to the terminal that has transmitted the CDMA code to the relay station, and transmits this uplink MAP to the relay station. (S53). However, at this time, the base station transmits the CDMA code related fields of the CDMA allocation message, that is, the repetition coding indicator field, the ranging code field, the ranging symbol field, and the ranging subchannel field without filling them.

  The reason why the base station does not fill the CDMA code related field of the CDMA allocation message in this way is that the base station knows the number of terminals, but has not received a CDMA code from the actual terminal, so it cannot know information about the CDMA code. Because. This empty field is filled by the relay station.

  When a relay station with a large number of connected terminals uses the resource request and allocation method of the present invention, there may be a disadvantage that a delay time for the resource request becomes long. In the present invention, when the number of terminals connected to the relay station is larger than the critical number (N), the base station periodically allocates a certain amount of resources to the relay station, and the relay station makes a resource request for the terminal. By making it possible to arbitrarily allocate already allocated resources to the terminal, it is possible to reduce the delay time for resource request and allocation.

  As mentioned above, although the technical thought regarding this invention was described with the accompanying drawing, this is only demonstrating only the best example of this invention, and does not limit this invention. Further, it is obvious that a person having ordinary knowledge in the technical field can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

The wireless access communication system based on the multi-hop orthogonal frequency division multiple access by the relay station of the present invention can be used for a mobile WiMAX system, an evolution system, and a military tactical communication system.

Claims (22)

In a resource request and allocation method in a wireless access communication system based on a multi-hop orthogonal frequency division multiple access comprising a number of terminals, relay stations and base stations,
A first stage in which the multiple terminals request the relay station to allocate resources;
A second stage in which the relay station grasps the number of the plurality of terminals;
A third step in which the relay station requests the base station to count information on the multiple terminals and to allocate resources to the multiple terminals;
A fourth stage in which the base station collectively allocates resources to the multiple terminals;
A resource request and allocation method, comprising: a fifth step in which the relay station allocates resources allocated to the plurality of terminals collectively to the terminals. The first stage includes
The resource request and allocation method according to claim 1, wherein the plurality of terminals requests resource allocation to the relay station through a bandwidth request CDMA code. The third stage includes
The method of claim 1, wherein the relay station transmits the number information of the multiple terminals to the base station through a multi-hop relay code report message. In the fourth step, the base station transmits a CDMA allocation message free of a CDMA code related field to the relay station;
The method of claim 1, wherein in the fifth step, the relay station inserts a CDMA code related field of the allocation message and then transmits the field to the base station.   The CDMA code related field includes a repetition coding indication field, a ranging code field, a ranging symbol field, and a ranging subchannel field. The resource request and allocation method according to claim 4, wherein:   The resource request and allocation method according to claim 1, wherein in the fifth step, the relay station allocates resources to the multiple terminals based on a resource allocation request order and priority.   In the fifth stage, when the terminal that requested the resource allocation in the first stage is out of the jurisdiction area of the relay station, the relay station allocates the resources collectively allocated to terminals out of the jurisdiction area. The resource request and allocation method according to claim 1, wherein allocation is not performed.   The resource request and allocation method according to claim 1, wherein the base station periodically allocates a resource of a certain size to the relay station even if the relay station does not request resource allocation. .   The resource request and allocation method according to claim 8, wherein the periodic resource allocation is performed when the number of terminals under the control of the relay station is larger than a specific number. In the resource request and allocation method in the relay station of the wireless access communication system based on multi-hop orthogonal frequency division multiple access comprising a number of terminals, relay stations and base stations,
When resource allocation is requested from the multiple terminals, a first step of determining the number of the multiple terminals;
A second step of requesting the base station to count the number of terminals and to allocate resources to the terminals;
A resource request comprising: a third step of allocating resources collectively allocated to the plurality of terminals to each terminal when resources are collectively allocated to the plurality of terminals from the base station; Assignment method.   The method of claim 10, wherein, in the first step, the plurality of terminals requests resource allocation to the relay station through a bandwidth request CDMA code.   The resource request and allocation method according to claim 10, wherein in the second step, the relay station transmits the number information of the plurality of terminals to the base station through a multi-hop relay code report message. .   In the third step, when a CDMA allocation message free of a CDMA code related field is transmitted from the base station, a CDMA code related field of the CDMA allocation message is inserted and then transmitted to the base station. The resource request and allocation method according to claim 10.   The CDMA code related field includes a repetition coding indication field, a ranging code field, a ranging symbol field, and a ranging subchannel field. The resource request and allocation method according to claim 13, wherein:   The resource request and allocation method according to claim 10, wherein in the third step, the relay station allocates resources to the multiple terminals based on a resource allocation request order and priority.   In the third stage, when the terminal that requested the resource allocation in the first stage is out of the jurisdiction area of the relay station, the relay station assigns the resources allocated collectively to the terminals out of the jurisdiction area. The resource request and allocation method according to claim 10, wherein the resource request is not allocated. In the resource request and allocation method in the base station of a radio access communication system based on a multi-hop orthogonal frequency division multiplex connection comprising a number of terminals, relay stations and base stations,
A first step in which the relay station requests information on the number of terminals that have requested resource allocation to the relay station and resource allocation to the plurality of terminals;
A second step of determining whether resource allocation to the plurality of terminals is possible;
A resource requesting and allocating method comprising: a third step of allocating resources to the plurality of terminals collectively via the relay station.   The method of claim 17, wherein in the first step, the base station receives the number information from the relay station through a multi-hop relay code report message.   [18] The resource request and allocation method according to claim 17, wherein in the third step, the base station transmits a CDMA allocation message free of a CDMA code related field to the relay station.   The CDMA code related field includes a repetition coding indication field, a ranging code field, a ranging symbol field, and a ranging subchannel field. The resource request and allocation method according to claim 19, wherein:   [18] The resource request and allocation method according to claim 17, wherein the base station periodically allocates a resource of a certain size to the relay station even when resource allocation is not requested from the relay station. .   The resource request and allocation method according to claim 21, wherein the periodic resource allocation is performed when the number of terminals under the control of the relay station is larger than a specific number.

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