KR101292578B1 - Apparatus and method of admission control for service flow in a multi-hop relay broadband wireless access communication system - Google Patents

Abstract

The present invention relates to an admission control apparatus and method for service flow in a broadband wireless access communication system using a multi-hop relay scheme. The method of operating an RS according to the present invention may include receiving a request message requesting an admission control decision for a service flow from an upper node, and determining whether the requested QoS parameter set in the request message can be supported. And forwarding the request message to a subordiate RS corresponding to a next hop if the QoS parameter set can be supported, and if the QoS parameter set cannot be supported, the requested QoS parameter. And transmitting a response message indicating that the set cannot be supported to the base station.

Relay communication system, multi-hop, call admission control

Description

Admission control device and method for service flow in a broadband wireless access communication system using a multi-hop relay method

The present invention relates to a broadband wireless access communication system using a multi-hop relay scheme, and more particularly, to an apparatus and method for signaling processing of a relay station and a base station for performing admission control on a service flow.

The 4G (4th generation) communication system, which is a next generation communication system, desires to provide various quality of service (QoS) services having a transmission speed of about 100 Mbps. In particular, the 4G communication system has mobility in a broadband wireless access (BWA) communication system such as a wireless local area network (LAN) system and a wireless metropolitan area network (MAN) system. And the quality of service (QoS) is evolving, and representative communication systems are the Institute of Electrical and Electronics Engineers (IEEE) 802.16d communication system and the IEEE 802.16e communication system.

The IEEE 802.16d communication system and the IEEE 802.16e communication system use the Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) method for a physical channel .

1 is a diagram schematically illustrating a structure of a general IEEE 802.16e communication system.

Referring to FIG. 1, the IEEE 802.16e communication system has a multi-cell structure, that is, a base station (BS) 110 having a cell 100 and a cell 150 and managing the cell 100. And a base station 140 that manages the cell 150 and a plurality of MSs 111, 113, 130, 151, and 153. Signal transmission and reception between the base stations 110 and 140 and the MSs 111, 113, 130, 151 and 153 is performed using the OFDM / OFDMA scheme. Herein, the MS 130 among the MSs 111, 113, 130, 151, and 153 is located in a boundary region of the cell 100 and the cell 150, that is, a handover region. Accordingly, when the MS 130 moves toward the cell 150 managed by the base station 140 while transmitting and receiving a signal with the base station 110, the serving BS moves to the base station 110. Is changed to the base station 140.

In the general IEEE 802.16e communication system, since signaling is transmitted and received through a direct link between the fixed base station and the MS as shown in FIG. 1, a reliable wireless communication link can be easily configured between the base station and the MS. However, since the IEEE 802.16e communication system has a fixed base station position, flexibility in the wireless network configuration is low. Therefore, it is difficult to provide an efficient communication service in a wireless environment where the traffic distribution and the call request amount change greatly.

In order to overcome such drawbacks, a multi-hop relay data transfer scheme may be applied to a general cellular wireless communication system such as the IEEE802.16e communication system using a fixed relay station or a mobile relay station or general MSs. Can be. The wireless communication system using the multi-hop relay method can quickly reconfigure the network in response to changes in the communication environment, and can operate the entire wireless network more efficiently. For example, the wireless communication system using the multi-hop relay scheme can expand the cell service area and increase the system capacity. That is, when the channel state between the base station and the MS is poor, a relay station may be provided between the base station and the MS to configure a multi-hop relay path through the relay station, thereby providing the MS with a better channel state. Further, by using the multi-hop relay scheme in a cell boundary region where the channel state is poor from the base station, a higher-speed data channel can be provided and the cell service area can be expanded.

Next, a structure of a wireless communication system using a multi-hop relay scheme for expanding the base station service area will be described.

2 is a diagram schematically illustrating a structure of a broadband wireless communication system using a multi-hop relay scheme for expanding a base station service area.

Referring to FIG. 2, the multi-hop relay wireless communication system has a multi-cell structure, that is, a cell 200 and a cell 240, and a base station (BS) 210 that manages the cell 200. ), A base station 250 that manages the cell 240, a plurality of MSs 211 and 213 located in an area of the cell 200, and the base station 210 manage the cell 200. A relay station that provides a multi-hop relay path between a plurality of MSs 221 and 223 present in an area 230 outside the area and between the base station 210 and the MSs 221 and 223 present in the area 230. 220, a plurality of MSs 251, 253, and 255 located within an area of the cell 240, and a plurality of MSs 251, 253, and 255 that exist in an area 270 that is managed by the base station 250 but outside the area of the cell 240. The relay station 260 provides a multi-hop relay path between the MSs 261 and 263 of the MSs and the MSs 261 and 263 existing in the region 270. Here, signal transmission and reception between the base stations 210 and 250, the relay stations 220 and 260, and the MSs 211, 213, 221, 223, 251, 253, 255, 261 and 263 are performed in the OFDM / OFDMA. Is done using the method.

In this case, the MSs 211 and 213 and the RS 220 included in the cell 200 area may directly transmit and receive a signal to or from the base station 210, but the MSs present in the area 230 may be used. 221 and 223 do not directly transmit and receive signals with the base station 210. Accordingly, the relay station 220 controls the area 230 and relays a signal between the base station 210 and the MSs 221 and 223 that cannot directly transmit and receive a signal, and the MSs 221 and 223. ) May transmit and receive signals to and from the base station 210 via the relay station 220. In addition, although the MSs 251, 253, and 255 included in the cell 240 region and the RS 260 may directly transmit and receive signals with the base station 250, the MSs present in the region 270 may be used. The fields 261 and 263 may not directly transmit / receive signals with the base station 250. Accordingly, the relay station 260 manages the area 270 and relays a signal between the base station 250 and the MSs 261 and 263 that cannot directly transmit and receive a signal, and the MSs 261 and 263. ) May transmit and receive signals to and from the base station 250 through the relay station 260.

Next, a structure of a wireless communication system using a multi-hop relay scheme for increasing system capacity will be described.

3 is a diagram schematically illustrating a structure of a broadband wireless communication system using a multi-hop relay scheme for increasing system capacity.

Referring to FIG. 3, the multi-hop relay wireless communication system includes a base station 310 and a plurality of MSs 311, 313, 321, 323, 331, and 333 and the base station 310 and the MSs 311 and 313. , 321, 323, 331, and 333 are relay stations 320 and 330 that provide a multi-hop relay path. The base station 310, the relay stations 320 and 330, and the MSs 311, 313, 321, 323, 331, and 333 transmit and receive signals using the OFDM / OFDMA scheme. The base station 310 manages the cell 300, and the MSs 311, 313, 321, 323, 331, and 333 and the relay stations 320 and 330 included in the cell 300 are connected to the base station. A signal can be directly transmitted and received with the 310.

However, when located near the edge of the cell 300, such as the some MSs (321, 323, 331, 333), a direct link between the base station 310 and the some MSs (321, 323, 331, 333) The received signal to noise ratio (SNR) may be low. Accordingly, the relay station 320 relays traffic between the base station 310 and the MSs 321 and 323, and the MSs 321 and 323 transmit and receive traffic to and from the base station 310 through the relay station 320. do. In addition, the relay station 330 relays traffic between the base station 310 and the MSs 331 and 333, and the MSs 331 and 333 exchange traffic with the base station 310 through the relay station 330. . In other words, the RSs 320 and 330 may provide high-speed data transmission paths to the MSs 321, 323, 331 and 333 to increase effective transmission rates and increase system capacity of the MSs.

Here, in the broadband wireless communication system using the multi-hop relay of FIG. 2 or 3, the relay stations 220, 260, 320, 330 are installed by the service provider, so that the base stations 210, 250, 310 It may be an infrastructure relay station known and managed in advance, or a client relay station operating as a subscriber station (SS or MS) or a relay station according to a situation. Also, the relay stations 220, 260, 320, and 330 may be fixed relay stations without mobility, nomadic relay stations (eg, laptops) having nomadic characteristics, or mobile relay stations with mobility such as the MS. Can be.

In the wireless communication system using the multi-hop relay method, a new service flow is generated to the terminal or a QoS parameter of a service flow that is already generated is changed while the terminal is communicating with the base station through the base station or the relay station. In this case, the base station and the relay station should be able to support the parameter of the new service flow or the service flow parameter to be changed.

In general, the service flow parameter of the terminal is determined in a policy server (QoS policy server) on the network. In order to determine the service flow parameter, the policy server needs to obtain parameter information that can be supported from the relay station as well as the base station. Here, the supportable parameter information is obtained through admission control at the corresponding node (base station or relay station).

As described above, when a service flow is generated for a terminal or a parameter of a previously generated service flow is changed in a multi-hop relay system, nodes on a data transmission path of the terminal may perform admission control. Signaling procedure is required.

Accordingly, an object of the present invention is to provide a signaling apparatus and method for performing admission control for a service flow in a broadband wireless communication system using a multi-hop relay scheme.

Another object of the present invention is to provide a signaling apparatus and method for nodes on a data transmission path of a terminal to perform admission control on a service flow of a terminal in a broadband wireless communication system using a multi-hop relay scheme.

According to an aspect of the present invention for achieving the above object, in a method of operating a relay station in a wireless communication system using a multi-hop relay, a request for requesting an admission control decision for a service flow from an upper node Receiving a message, determining whether to support the requested QoS parameter set in the request message, and if the QoS parameter set can be supported, the requesting message is a subordiate RS corresponding to the next hop. And forwarding to the base station if the QoS parameter set cannot be supported, and transmitting a response message indicating that the requested QoS parameter set cannot be supported.

According to another aspect of the present invention, in the admission control method for the service flow in a wireless communication system using a multi-hop relay, when the service flow change of the terminal is required, the base station, the request message requesting the admission control decision Transmitting to the relay stations on the data transmission path, performing the admission control with the requested QoS parameter set in the request message, and transmitting the requested QoS parameter set to the relay station on the data transmission path. And transmitting, by the relay station, the request message to a lower relay station corresponding to a next hop on the data transmission path.

According to still another aspect of the present invention, a relay station apparatus in a wireless communication system using a multi-hop relay, comprising: a receiving unit for receiving a request message for requesting an admission control decision on a service flow from an upper node, and the request in the request message. A control unit that can support the requested QoS parameter set, and if the requested QoS parameter set can be supported, transmit the request message to a lower relay station corresponding to the next hop on a data delivery path, and request the QoS parameter set. If it can not support, characterized in that it comprises a transmitter for transmitting a response message to the base station indicating that the requested QoS parameter set can not be supported.

According to still another aspect of the present invention, in a method of operating a base station in a wireless communication system using a multi-hop relay, when a service flow change of a terminal is required, a request message for requesting an admission control decision is transmitted. Transmitting to the relay stations on the path, receiving a response message for the request message from the relay station on the data transmission path, and performing admission control on the service flow based on the information of the response message; And transmitting a message including the accepted service flow parameter to the terminal.

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As described above, the present invention defines the signaling between the base station and the relay station for performing the admission control for the QoS parameters of the service flow in the multi-hop relay system, the base station can manage the resource condition (resource condition) of the relay station . In addition, the base station has an advantage of easily reconfiguring a path for supporting a service of the terminal or handover control of the terminal based on the resource state of the relay station.

Hereinafter, the operation principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Hereinafter, the present invention will propose a signaling processing method between a base station and a relay station for admission control of a service flow of a terminal in a broadband wireless access communication system using a multi-hop relay scheme.

Here, the broadband wireless access communication system using the multi-hop relay method is, for example, using Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). Communication system. In the broadband wireless access communication system using the multi-hop relay method, since the OFDM / OFDMA method is used, high-speed data transmission is possible by transmitting a physical channel signal using a plurality of sub-carriers. It is possible to support the mobility of the terminal through a multi-cell) structure.

In the following description, a broadband wireless access communication system is described as an example, but the present invention may be equally applicable to a cellular-based communication system using a multi-hop relay method.

4 is a signal flow diagram for performing admission control for a service flow addition request of a terminal in a broadband wireless communication system using a multi-hop relay method according to an exemplary embodiment of the present invention.

Referring to FIG. 4, in step 401, the terminal 460 transmits a DSA-REQ (Dynamic Service Addition-REQuest) message to the base station 400 to generate a new connection A. FIG. Here, the DSA-REQ message may include parameter information (eg, a quality of service set, a QoS profile identifier, etc.) for a service flow to be generated.

Then, the base station 400 and the DSA-REQ message including the service flow parameter for the connection A received from the terminal 460 in step 403 and the relay station 1 (440) on the data transmission path of the terminal; Relay station 2 (450) is transmitted. That is, the relay station on the data transmission path of the terminal is inquired whether the service flow parameter for the connection A is accepted.

In step 405, the RS 1 440 performs admission control with the service flow parameter included in the DSA-REQ message. That is, RS 1 440 determines whether it can support the requested QoS parameter set. In this case, it is assumed that the service flow parameter has been accepted. If the service flow parameter is accepted, RS 1 440 forwards the DSA-REQ message to subordinate RS 2 450 corresponding to the next hop on the data transmission path of the UE in step 407.

Subsequently, RS 2 450 performs admission control with the request service flow parameter included in the DSA-REQ message in step 409. In this case, it is assumed that the service flow parameter is not accepted. If the requested QoS parameter set cannot be supported, the RS 2 450 may transmit a DSA-RSP (Dynamic Service Addition-ReSPonse) message indicating that it cannot support the requested QoS parameter set in step 411. In step 413, the RS 1 440 forwards the DSA-RSP message to the base station 400. The DSA-RSP message may include a confirmation code indicating that the requested QoS parameter cannot be supported, an acceptable QoS parameter set that may be accepted by the relay station 2 450, and the like. . In this case, the QoS parameter information acceptable to RS 2 450 may include a parameter that cannot be supported among the requested QoS parameter sets, and a parameter value that RS 2 450 can support for the parameter. Can be.

For example, when it is assumed that 'minimum required traffic amount', which is one of the requested QoS parameter sets for the connection A included in the DSA-REQ message received in step 407, is 50, the relay station 2 (450). In the case where '30' is supported for the 'minimum required traffic amount', the DSA-RSP message may include a supportable parameter value '30' for the 'minimum required traffic amount'.

As described above, the information collected from the relay stations on the corresponding path, in addition to determining whether to support the service flow of the terminal, if the support for the service flow is not possible, handover the terminal to a supporting relay station or base station. It may be used as a triggering point or as load control information of the base station.

In step 415, the base station 400 performs admission control on the connection A based on the information of the received DSA-RSP message, and determines a parameter for the connection A according to the admission control result. Meanwhile, although the QoS parameter determination for the connection A has been described as being performed in the base station 400, the QoS parameter determination may be performed in a policy server, and signaling between the policy server and the base station 400 is a known technique. Detailed description will be omitted. The parameter for the connection A determined in step 415 may be a service flow parameter modified based on the information collected from the relay station 2 450 or information indicating that the connection A cannot be serviced.

In general, the Policy Server is responsible for setting up QoS parameters (e.g., traffic priority, maximum sustained rate, minimum reservation rate) for each QoS flow (e.g., UGS, nrtPS, rtPS, ertPS, etc.). minimum reserved rate), maximum latency, grant interval, and so on. When a new service is started, the terminal transmits a session initiation through the application layer to a corresponding network entity (eg, an IMS (inernet protocol multimedia subsystem) server) of a core service network (CSM), and the corresponding network entity. Triggers the policy server. Then, the policy server may deliver the QoS parameter set for the requested service to the terminal through the application layer, or deliver the DSA triggering including the QoS parameter set to the serving base station. In the former case, the terminal may transmit a DSA-REQ message including the QoS parameter set to the base station, and in the latter case, the base station may start signaling negotiation by transmitting the DSA-REQ message to the terminal. In the case of a multi-hop system, since the service level that can be supported for each node is different, a change in the QoS parameter set of the flow may be required as described above (step 415). If the base station has an allowable range, the base station may modify a parameter for the corresponding service flow within the allowable range. If the base station does not have the allowable range, the base station may request a policy server to determine a parameter for the corresponding service flow, and receive the determined service flow parameter from the policy server.

In step 417, the base station 400 transmits a DSA-RSP message including the determined parameter to the terminal 460 through the relay station 1 440 and the relay station 2 450. In step 419, the terminal 460 transmits a DSA-ACK (DSA-ACKnowledgement) message to the base station 400 as a response to the DSA-RSP message.

Then, the base station 400 transmits a DSA-ACK message including the service flow parameter determined for the connection A to the relay station 1 440 in step 421, and the relay station 1 440 sends the DSA to the DSA in step 423. Delivers an ACK message to RS 2 450 corresponding to the next hop. That is, the determined service flow parameter is informed to the relay stations on the service path of the terminal. Thereafter, the base station 400 and the relay stations 440 and 450 provide the corresponding service to the terminal 460 based on the determined service flow parameter.

The above-described procedure of FIG. 4 has been described on the assumption that the terminal requests to create a connection (MS_init DSA), but when the base station requests to create a connection (BS_init DSA), the service flow parameter for a connection for which the terminal has already been created In the case of requesting the change (MS_init DSC), the admission control procedure according to FIG. 4 may be performed even when the base station requests the change of the service flow parameter for the connection already created (BS_init DSC). If the service flow parameter for a connection already created is changed, the Dynamic Service Change / DSC-RSP / DSC-ACK message is used instead of the above-described DSA-REQ / DSA-RSP / DSA-ACK message. Can be.

Next, the admission control procedure in the case of transmitting data of the terminal using the tunneling (tunneling) mode will be described. That is, when a tunnel is created between an access node of a base station and an access node (terminal relay station of a data transmission path of a terminal), an admission control procedure considering a case where a service flow parameter of the tunnel is changed will be described. Here, the case where the service flow parameter of the tunnel is changed may include a case where a new connection using the tunnel is added or a service flow parameter value of an already created connection using the tunnel is changed.

FIG. 5 illustrates an admission control procedure for changing a service flow for a tunnel in a broadband wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

Referring to FIG. 5, the tunnel 1 between the base station 500, the relay station 1 540, and the relay station 2 550 in the data path of the terminal for data transmission of the connection A of the terminal 560 is set. It is assumed that the tunnel 1 has a separate service flow parameter (QoS parameter set) for the tunnel 1. In step 501, the base station 500, the relay station 1 540, and the relay station 2 550 transmit data for connection A of the terminal 560 using the tunnel 1.

If it is necessary to change the service flow parameter for connection A of the terminal 560, the terminal 560 transmits a DSC-REQ message requesting a change of the service flow parameter value for the connection A in step 503. Send to 500.

Then, the base station 500 performs admission control based on the information of the DSC-REQ message in step 505. At this time, when it is determined that the service flow parameter change set in tunnel 1 is necessary through the admission control, the base station 500 determines the service flow parameter value required for the tunnel 1.

In step 507, the base station 500 transmits a DSC-REQ message including the determined service flow parameter value of the tunnel 1 to the relay station 1 540. Then, RS 1 540 performs admission control based on the information of the DSC-REQ message in step 509. That is, RS 1 540 determines that it can support the requested QoS parameter set. In this case, it is assumed that the corresponding service flow parameter is not accepted. If the service flow parameter is not accepted, the RS 1 540 and the RS 1 540 confirm that it cannot support the QoS parameter set requested for the tunnel 1 in step 511. A DSC-RSP message including an acceptable QoS parameter set is generated and the generated DSC-RSP message is transmitted to the base station 500. That is, the DSC-RSP message may include a service flow parameter that the relay station 1 540 cannot support and a service flow parameter value that the relay station 1 540 can accommodate for the parameter.

On the other hand, the base station 500 can adjust the service flow parameter value for the tunnel 1 or the service flow parameter value for the tunnel 1 in step 513, so the service flow parameter for connection A of the terminal. Review whether to reject the change request. Here, it is assumed that the service flow parameter value for the tunnel 1 is readjusted. When the service flow parameter value for the tunnel 1 is readjusted, the base station 500 transmits a DSC-REQ message including the service flow parameter readjusted for the tunnel 1 to the relay station 1 540 in step 515. .

In step 517, the RS 1 540 determines whether the service flow parameter readjusted for the tunnel 1 can be accepted. In this case, it is assumed that the readjusted service flow parameter is accepted. That is, when it is determined that the requested QoS parameter set can be supported, the RS 1 540 may transmit a DSC-REQ message including the requested QoS parameter set corresponding to the next hop on the terminal data transmission path in step 519. Forward to lower relay station 2 (550).

Then, RS 2 550 performs admission control based on the information of the DSC-REQ message received in step 521. In this case, it is assumed that the corresponding service flow parameter is not accepted. If the service flow parameter is not accepted, RS 2 550 confirms in step 523 that it cannot support the requested QoS parameter set for tunnel 1 and in RS 2 550. The relay station 2 550 transmits a DSC-RSP message including the acceptable service flow parameter value to the relay station 1 540 for the unsupported service flow parameter, and the relay station 1 540 in step 525. The DSC-RSP message is forwarded to the base station 500.

Then, the base station 500 can readjust the service flow parameter value for the tunnel 1 or the service for the tunnel 1 based on the information of the DSC-REQ message received from the relay station 2 550 in step 527. Since the flow parameter value cannot be readjusted, whether or not to reject the service flow parameter change request for connection A of the terminal is examined. Here, it is assumed that the service flow parameter value for the tunnel 1 is readjusted.

Thereafter, the base station 500 transmits a DSC-RSP message including the QoS parameter set for the tunnel 1 determined in step 529 to the terminal 560. At this time, the determined QoS parameter set for the tunnel 1 is a service flow parameter updated based on the information received from the relay station 2 550 or the terminal 560 requests to change the service flow parameter of the connection A requested. It may be information indicating that it cannot be done.

In step 531, the terminal 560 transmits a DSC-ACK message to the base station 500 in response to the DSC-RSP message. Then, in step 533, the base station 500 transmits a DSC-ACK message including the determined parameter for the tunnel 1 to the RS 1 540 on the service path of the terminal. In step 535, the RS 1 540 sets the information (service flow parameters) of the DSC-ACK message in the corresponding table, and the DSC-ACK message corresponds to the next hop on the service path of the UE. Forward to relay station 2 (550). RS 2 550 then sets the information of the DSC-ACK message in the corresponding table. Thereafter, the base station 500 and the relay stations 540 and 550 provide the service to the terminal 560 based on the negotiated service flow parameters.

6 illustrates an operation of a base station in a broadband wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

Referring to FIG. 6, the base station first determines whether a service flow change of the terminal is necessary in step 601. Here, the service flow change is a service flow for a connection (meaning both an individual connection and a tunneling connection) that the terminal has already created when the terminal requests to generate a connection and when the base station requests to create a connection. In the case of changing the parameter, it may occur when the base station changes the service flow parameter for the connection (which means both individual connection and tunneling connection) that has already been created. The new connection may be created through the DSA procedure, and the service flow parameters of the previously created connection may be changed through the DSC procedure.

When the service flow of the terminal needs to be changed, the base station generates a message requesting admission control in step 603. Here, the admission control request message may be, for example, one of a DSA-REQ message and a DSC-REQ message, or may be another message defined separately.

In step 605, the base station transmits the admission control request message to the relay stations on the data transmission path of the terminal. Here, the admission control request message includes a service flow parameter (QoS parameter set) for which admission control is required.

After transmitting the admission control request message, the base station determines whether a response message to the admission control request message is received in step 607. The response message may be, for example, one of a DSA-RSP message and a DSC-RSP message, or may be another message that is separately defined.

When the response message to the acceptance request message is received, the base station determines whether the response message is received from the access relay station (the last relay station on the path) of the terminal in step 609. If not the access relay station, the base station proceeds to step 621 to determine whether to adjust the service flow parameters based on the information in the response message, or whether to reject the service flow change (generation or parameter change) of the terminal. At this time, when the service flow parameter is readjusted, the base station returns to step 603 to request admission control again to the relay stations on the corresponding path.

If the access relay station, the base station proceeds to step 611 to finally determine the service flow parameters based on the information in the response message. In this case, the service flow parameter may be adjusted again or the service flow change of the terminal may be rejected.

When the service flow parameter is finally determined, the base station proceeds to step 613 to generate a message including the determined service flow parameter. Here, the message may be, for example, one of a DSA-RSP message and a DSC-RSP message, or may be another message defined separately.

 In step 615, the base station transmits the generated message to the terminal. In step 617, the base station determines whether an acknowledgment (ACK) message is received from the terminal. Upon receiving the ACK message, the base station transmits a message including the determined service flow parameter to the relay stations of the corresponding path in step 619. In this case, the message may be, for example, one of a DSA-ACK message and a DSC-ACK message, or may be another message defined separately. The service flow parameter finally determined by this procedure is set in the database (memory), and the base station provides a service to the terminal based on the set service flow parameter.

7 illustrates an operation procedure of a relay station in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

Referring to FIG. 7, in step 701, the RS checks whether a message for requesting admission control is received from an upper node (base station or upper RS). Here, the admission control request message may be one of, for example, a DSA-REQ message and a DSC-REQ message, or may be another message that is separately defined. Here, the admission control request message includes service flow parameter information (QoS parameter set) for which admission control is requested.

Upon receiving the admission control request message, the RS performs admission control with the requested QoS parameter set included in the message in step 703. That is, the RS determines whether it can support the requested QoS parameter set. In step 705, the RS checks whether the RS is an access RS located at an end of the data transmission path.

If it is not the access relay station, that is, if there is a next hop relay station (lower relay station), the relay station proceeds to step 707 to check whether the requested QoS parameter set is accepted from the admission control result. If so, the RS proceeds to step 713 to forward the admission control request message received from the higher node to the next hop relay station on the path.

On the other hand, if the requested QoS parameter set cannot be supported, the RS generates a response message indicating that it cannot support the requested QoS parameter set in step 709. In step 711, the RS transmits the generated response message to the BS.

On the other hand, if it is determined in step 705 that the access relay station itself, the relay station proceeds to step 715 to generate the response message including the admission control result. The relay station transmits the response message to the base station in step 717.

The response message to the admission control request includes a confirmation code indicating that it cannot support the requested QoS parameter set and acceptable parameter information (an unsupportable parameter identifier and a supportable value for that parameter). It may include. In addition, the response message may be, for example, one of a DSA-RSP message and a DSC-RSP message, or may be another message defined separately.

On the other hand, the relay station may receive a message (DSA-ACK, DSC-ACK) including the service parameter information finally determined from the base station after the procedure of FIG. 7, the relay station when the message is received The final service flow parameter is set in the memory. Thereafter, the RS provides a service to the corresponding terminal based on the set service flow parameter.

8 is a block diagram of a base station (or relay station) according to an embodiment of the present invention. Here, since the base station and the relay station having the same interface module (communication module) have the same block configuration, the following description will describe the operation of the base station and the relay station with the apparatus of FIG. In addition, the following description will be made on the assumption of a TDD-OFDMA system. However, the present invention can be easily applied to an FDD-OFDMA system, a hybrid system using TDD and FDD together, and a cellular based system using another resource partitioning scheme.

As shown, the base station (or relay station) according to the present invention, the service flow parameter storage unit 800, the control unit 802, the message processing unit 804, the message generating unit 806, RF receiver 808, ADC 810, an OFDM demodulator 812, a decoder 814, an encoder 816, an OFDM modulator 818, a DAC 820, an RF transmitter 822, and a duplexer 824.

Referring to FIG. 8, the duplexer 824 first transmits a transmission signal from the RF transmitter 822 through an antenna according to a duplexing scheme, and provides a received signal from the antenna to the RF receiver 808. For example, in a time division duplex (TDD) scheme, the duplexer 824 transmits a signal from the RF transmitter 822 through an antenna in a transmission section and is received through the antenna in a reception section. The signal is transmitted to the RF receiver 808.

The RF receiver 808 converts a radio frequency (RF) signal received through an antenna into a baseband analog signal. The ADC 810 converts an analog signal from the RF receiver 808 into sample data and outputs the sample data. The OFDM demodulator 812 converts the sample data output from the ADC 810 into fast fourier transform (FFT) into data of a frequency domain, and selects and outputs data of subcarriers to be actually received from the data of the frequency domain. .

The decoder 814 demodulates and decodes the data from the OFDM demodulator 812 according to a predetermined modulation level (MCS level). The message processor 804 interprets the control message from the decoder 814 and provides the result to the controller 802.

The controller 802 controls an operation based on the information from the message processor 804, and generates and provides information to be transmitted to the message generator 806. Herein, it is assumed that the controller 802 performs admission control on service flow parameters. The service flow parameter storage unit 800 manages service flows generated for each of the terminals, and manages service flow parameters (QoS parameter sets) accepted for each service flow.

The message generator 806 generates a message with various types of information provided from the controller 802 and outputs the message to the encoder 816 of the physical layer.

The encoder 816 codes and modulates the data from the message generator 816 according to a predetermined modulation level (MCS level). The OFDM modulator 818 outputs sample data (OFDM symbols) by performing IFFT (Inverse Fast Fourier Transform) on the data from the encoder 816. The DAC 820 converts the sample data into an analog signal and outputs the analog signal. The RF transmitter 822 converts an analog signal from the DAC 820 into a radio frequency (RF) signal and transmits the same through an antenna.

In the above configuration, the control unit 802 is a protocol control unit, and controls the message processing unit 804 and the message generating unit 806. That is, the controller 802 may perform the functions of the message processor 804 and the message generator 806. In the present invention, these are separately configured to distinguish the respective functions. Therefore, in actual implementation, all of them may be configured to be processed by the controller 802, and only some of them may be configured to be processed by the controller 802.

In addition, the controller 802 receives information necessary for performing protocol processing to the corresponding component of the physical layer or generates a control signal to the corresponding component of the physical layer.

Then, the operation of the base station and the relay station according to the present invention based on the configuration of FIG. 8 will be described. Hereinafter, a description will be given of the signaling processing performed in the media access control (MAC) layer.

First, the operation of the base station is as follows.

The controller 802 determines whether a service flow change of the terminal is necessary, and triggers a message generator 806 when the service flow change (which means including service flow generation and parameter change of a pre-generated service flow) is needed. . Then, the message generator 806 generates an acceptance control request message (eg, DSA-REQ message, DSC-REQ message) under the control of the controller 802 and transmits the message to the physical layer unit. Here, the admission control request message may include QoS parameter set information for which admission control is requested. On the other hand, the message generated by the message generator 806 is processed in a form that can be transmitted from the physical layer and then transmitted to the corresponding relay station.

Thereafter, the controller 802 checks whether a response message for the admission control request message is received, and whether the service flow parameter readjustment is necessary when the response message is received, whether to reject the service flow change of the terminal or finalizes the service flow parameter. Determine whether to confirm.

If the service flow parameter is readjusted, the message generator 806 generates an admission control request message including the readjusted service flow parameter and transmits it to the physical layer unit. The admission control request message thus generated is physical layer encoded and transmitted to the corresponding relay station.

If the service flow parameter is finally determined, the message generator 806 generates a message (eg, a DSA-RSP message or a DSC-RSP message) including the finally determined service flow parameter and transmits the message to the physical layer unit. . The generated message is physical layer encoded and transmitted to the terminal.

Then, when receiving an acknowledgment message (eg, DSA-ACK message, DSC-ACK message) from the terminal, the message generator 806 includes a message (eg, DSA-ACK message) including the final determined service flow parameter. , DSC-ACK message) is generated and delivered to the physical layer. The message thus generated is physical layer encoded and transmitted to relay stations on the path.

Meanwhile, the finally determined service flow parameter is stored in the service flow parameter storage unit 800. Thereafter, the controller 802 provides a service to the corresponding terminal based on the service flow parameter set in the storage unit 800.

Next, the operation of the relay station is as follows.

The controller 802 checks whether a message for requesting admission control is received from an upper node (base station or upper relay station), and performs admission control with the requested QoS parameter set in the message upon receiving the admission control request message.

If the relay station is an access relay station located at the end of the path, the message generator 806 generates a response message (eg, DSA-RSP message, DSC-RSP message) including the admission control result. The generated message is physical layer encoded and transmitted to the base station.

If it is not the access relay station and can support the requested QoS parameter set, the message generator 806 generates an admission control request message including the corresponding service flow parameters. The message thus generated is physical layer encoded and sent to the next hop relay station along the path.

If it is not the access relay station and cannot support the requested QoS parameter set, the genital message generator 806 may reply with a confirmation code indicating that it cannot support the requested QoS parameter set and acceptable QoS parameter information. (E.g. DSA-RSP message, DSC-RSP message) The generated response message is physical layer encoded and transmitted to the base station.

Meanwhile, the controller 802 checks whether a final service flow parameter (for example, a DSA-ACK message or a DSC-ACK message) is received from an upper node, and if the final service flow parameter is received, the service flow. The parameter storage unit 800 stores the result. Thereafter, the controller 802 provides a service to the corresponding terminal based on the service flow parameter set in the storage unit 800.

9 illustrates a signal flow for performing admission control for a service flow addition request of a terminal in a broadband wireless communication system using a multi-hop relay method according to an embodiment of the present invention.

Referring to FIG. 9, the terminal 960 first transmits a DSA-REQ message to the base station (MR-BS) 900 to create a new connection in step 901. Then, the base station 900 transmits the DSA-REQ message including the requested QoS parameter set to the relay stations on the data transmission path of the terminal in step 903.

Then, the in-RS 940 on the data path performs admission control with the requested QoS parameter set included in the DSA-REQ message from the base station in step 905. That is, the RS 940 checks whether it can support the requested QoS parameter set. At this time, if the requested QoS parameter set can be supported, the relay station 940 forwards the DSA-REQ message to the lower relay station 950 of the next hop. It is assumed here that the relay station 940 cannot support the requested QoS parameter set.

If the requested QoS parameter set is not accepted, the RS 940 includes a service flow parameter value that it can accept in the DSA-REQ message received from the higher base station in step 907, and the DSA- Deliver a REQ message to the next hop relay station.

Similarly, the next hop relay station also performs admission control with the requested service flow parameters in the DSA-REQ message received from the upper relay station. At this time, if the requested service flow parameter is not accepted, the relay station includes an acceptable service flow parameter value in the DSA-REQ message and delivers it to the next hop relay station. At this time, if the service flow parameter value supported by the upper relay station is already included in the DSA-REQ message received from the upper relay station, the intermediate relay station adds or updates the acceptable service flow parameter value. The DSA-REQ message is forwarded to the next hop relay station.

In this process, when the DSA-REQ message is delivered to the access relay station 950 which is the last relay station on the data transmission path of the terminal, the access relay station 950 is identical to the other relay station in step 909 in the DSA-REQ message. Perform admission control with the requested QoS parameter set. In this case, when the requested QoS parameter set is not accepted, the access relay station 950 adds or updates a service flow parameter value that can be accepted in step 911, and includes the same in the DSA-RSP message to the relay station 940. ). Then, the RS 940 forwards the DSA-RSP message to the BS 900 in step 913. Here, the DSA-RSP message may include a confirmation code indicating that the requested QoS parameter set cannot be supported and QoS parameter information that can be allowed by the RS on the terminal path. The information of the DSA-RSP message may be used to determine a service flow parameter of the terminal at a base station and a policy server.

On the other hand, when the DSA-RSP message is received, the base station 900 finally determines the service flow parameter of the terminal and the DSA-RSP message including the determined service flow parameter to the terminal 960 in step 915. The terminal 960 transmits an acknowledgment message (DSA-ACK) to the base station 900.

In step 917, the base station 900 transmits a DSA-ACK message including the determined service flow parameters to the relay station 940, and the relay station 940 transmits the DSA-ACK message to the relay station 950. To pass.

The operation of FIG. 9 may be performed by adding or updating a service flow of a terminal by BS-initiated or by updating an existing service flow by MS-initiated and by adding or updating a tunnel service flow. This can be applied when updating.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a diagram schematically showing the structure of a general IEEE 802.16e communication system.

2 is a diagram schematically illustrating a structure of a broadband wireless communication system using a multi-hop relay scheme for expanding a base station service area.

3 is a schematic diagram illustrating a structure of a broadband wireless communication system using a multi-hop relay scheme for increasing system capacity.

4 is a signal flow diagram for performing admission control for a service flow addition request of a terminal in a broadband wireless communication system using a multi-hop relay method according to an embodiment of the present invention.

5 is a diagram illustrating an admission control procedure for changing a service flow for a tunnel in a broadband wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

6 is a diagram illustrating the operation of a base station in a broadband wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

7 is a diagram illustrating an operation procedure of a relay station in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

8 is a block diagram of a base station (or relay station) according to an embodiment of the present invention.

9 is a diagram illustrating a signal flow for performing admission control for a service flow addition request of a terminal in a wideband wireless communication system using a multi-hop relay scheme according to another embodiment of the present invention.

Claims (33)

In the method of operating a relay station in a wireless communication system using a multi-hop relay, Receiving a request message requesting an admission control decision for a service flow from an upper node; Determining whether the requested quality of service (QoS) parameter set in the request message can be supported; Forwarding the request message to a subordiate RS corresponding to a next hop if the requested QoS parameter set can be supported; If the requested QoS parameter set cannot be supported, sending a response message to the base station indicating that the requested QoS parameter set cannot be supported; And the response message includes an acceptable QoS parameter set that is acceptable at the relay station. The method of claim 1, The request message, characterized in that the DSA-REQ (Dynamic Service Addition-REQuest) message, DSC-REQ (Dynamic Service Change-REQuest) message. The method of claim 1, The response message, characterized in that the DSA-RSP (Dynamic Service Addition-ReSPonse) message, DSC-RSP (Dynamic Service Change-ReSPonse) message. The method of claim 1, And the response message includes a confirmation code (CC) indicating that the requested QoS parameter set cannot be supported. The method of claim 1, Receiving an acknowledgment message including an accepted service flow parameter from the base station; And setting the accepted service flow parameter. The method of claim 5, The acknowledgment message is characterized in that one of the DSA-ACK message, DSC-ACK message. The method of claim 1, The service flow is one of an individual service flow and a tunnel service flow. In the admission control method for the service flow in a wireless communication system using a multi-hop relay, When the service flow change of the terminal is required, transmitting, by the base station, a request message for requesting an admission control decision to relay stations on a data transmission path; Performing, by the relay station on the data transmission path, admission control with the requested Quality of Service (QoS) parameter set in the request message; Transmitting, by the relay station, the request message to a lower relay station corresponding to a next hop on the data transmission path when the requested QoS parameter set can be supported; If the relay station cannot support the requested QoS parameter set, the relay station sends a response message to the base station indicating that the requested QoS parameter set cannot be supported; And the response message includes an acceptable QoS parameter set that is acceptable at the relay station. 9. The method of claim 8, The request message, characterized in that the DSA-REQ (Dynamic Service Addition-REQuest) message, DSC-REQ (Dynamic Service Change-REQuest) message. delete 9. The method of claim 8, The response message is one of a DSA-RSP message and a DSC-RSP message. 9. The method of claim 8, When the response message is received from the relay station, the base station performing admission control; Transmitting, by the base station, a message including an accepted service flow parameter to the terminal; Sending, by the base station, an acknowledgment message including the accepted service flow parameter to relay stations on the data delivery path. The method of claim 12, The confirmation message is characterized in that one of the DSA-ACK message and DSC-ACK message. 9. The method of claim 8, The service flow change of the terminal is performed when the terminal requests to create a connection, when the base station requests to create a connection, when the terminal requests to change a service flow parameter of a previously created connection, and the base station services a previously generated connection. Required when requesting a flow parameter change. 9. The method of claim 8, The service flow is one of a separate service flow and a tunnel service flow. In a relay station apparatus in a wireless communication system using a multi-hop relay, A receiving unit for receiving a request message for requesting an admission control decision on a service flow from an upper node; A control unit which can support the requested Quality of Service (QoS) parameter set in the request message; If the requested QoS parameter set can be supported, the request message is transmitted to a lower relay station corresponding to the next hop on a data delivery path, and if the requested QoS parameter set cannot be supported, the requested QoS parameter set is transmitted. It includes a transmitter for transmitting a response message indicating that it can not support to the base station, And wherein the response message includes an acceptable QoS parameter set that can be accepted by the relay station. 17. The method of claim 16, The request message, characterized in that the DSA-REQ (Dynamic Service Addition-REQuest) message, DSC-REQ (Dynamic Service Change-REQuest) message. 17. The method of claim 16, Wherein the response message is one of a DSA-RSP (Dynamic Service Addition-ReSPonse) message and a DSC-RSP (Dynamic Service Change-ReSPonse) message. 17. The method of claim 16, And the response message includes a confirmation code (CC) indicating that the requested QoS parameter set cannot be supported. 17. The apparatus of claim 16, Receive an acknowledgment message including the accepted service flow parameter from the base station, and set the accepted service flow parameter. 21. The method of claim 20, Wherein the acknowledgment message is one of a DSA-ACK message and a DSC-ACK message. 17. The method of claim 16, And wherein the service flow is one of an individual service flow and a tunnel service flow. A method of operating a base station in a wireless communication system using a multi-hop relay, When a service flow change of the terminal is required, transmitting a request message requesting an admission control decision to relay stations on a data transmission path of the terminal; Receiving a response message to the request message from the relay station on the data transmission path; Performing admission control on the service flow based on the information of the response message; Transmitting a message including the accepted service flow parameter to the terminal, And the response message includes a quality of service (QoS) parameter set that is acceptable to the relay station. 24. The method of claim 23, The service flow change of the terminal is performed when the terminal requests to create a connection, when the base station requests to create a connection, when the terminal requests to change a service flow parameter of a previously created connection, and the base station services a previously generated connection. Required when requesting a flow parameter change. 24. The method of claim 23, And the service flow is one of an individual service flow and a tunnel service flow. 24. The method of claim 23, The request message, characterized in that the DSA-REQ (Dynamic Service Addition-REQuest) message, DSC-REQ (Dynamic Service Change-REQuest) message. 24. The method of claim 23, The response message, characterized in that the DSA-RSP (Dynamic Service Addition-ReSPonse) message, DSC-RSP (Dynamic Service Change-ReSPonse) message. 24. The method of claim 23, And the response message includes a confirmation code (CC) indicating that the requested QoS parameter set in the request message cannot be supported. 24. The method of claim 23, And sending an acknowledgment message containing the accepted service flow parameter to relay stations on the data delivery path.  30. The method of claim 29, The confirmation message is characterized in that one of the DSA-ACK message and DSC-ACK message. delete delete delete

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