JP2010524325A - Data retransmission apparatus and method in wireless communication system using multi-hop relay system - Google Patents

Abstract

The present invention provides an apparatus and method for transmitting a control message for retransmission in a wireless communication system using a multi-hop relay scheme.
The present invention relates to a process for confirming whether or not an error has occurred in data received from an upper node, and when a message indicating whether or not an error has occurred is received from a lower node. And the process of transmitting the error occurrence presence / absence message received from the lower node to the upper node at the same time. There is an advantage that the control message can be simultaneously transmitted to the upper node.

Description

  The present invention relates to an apparatus and method for making an automatic retransmission request (hereinafter referred to as ARQ) in a wireless communication system, and more particularly, to control for ARQ in a wireless communication system using a multi-hop relay scheme. The present invention relates to an apparatus and a method for transmitting a message.

  In a wireless communication system, an error occurs in specific data depending on a channel state of a wireless resource that transmits data. Control and recovery techniques for such errors are roughly classified into ARQ techniques and FEC (Forward Error Check) techniques. Here, the ARQ technique is a technique for requesting transmission to the transmission end for data lost at the reception end. The FEC technique is a technique for correcting an error for data lost at the receiving end.

  When the ARQ technique is used in the wireless communication system, the receiving end decodes the received packet to check whether an error has occurred. At this time, if no error occurs in the received packet, the receiving end transmits an ACK message to the transmitting end.

  Should an error occur in the received packet, the receiving end transmits a NACK message to the transmitting end.

  When receiving the ACK message from the receiving end, the transmitting end transmits a new packet. On the other hand, when a NACK message is received from the receiving end, the transmitting end retransmits the previous packet to the receiving end.

  Recently, a wireless communication system provides a relay service using a relay station in order to provide an excellent wireless channel to terminals located in cell boundaries or shaded areas. That is, a wireless communication system providing a relay service relays data transmitted and received between a base station and a terminal using a relay station, and provides an excellent wireless channel between the base station and the terminal. Can do.

  Therefore, a wireless communication system that uses a relay scheme requires an ARQ performance method using a relay station.

  Accordingly, an object of the present invention is to provide an apparatus and method for transmitting a multiplex control message for an automatic retransmission request (Automatic Retransmission reQuest) in a wireless communication system using a multi-hop relay scheme.

  Another object of the present invention is to provide an apparatus and method for allocating a channel of a multiplex control message to be transmitted for an automatic retransmission request in a wireless communication system using a multi-hop relay scheme.

  It is still another object of the present invention to provide an apparatus and method for allocating a control channel of multiple ACK / NACK to be transmitted for an automatic retransmission request in a wireless communication system using a multi-hop relay scheme.

  In order to achieve the object of the present invention, according to the first aspect of the present invention, a relay station operating method in a wireless communication system using a relay method confirms whether or not an error has occurred in data received from an upper node. And, if no error occurs in the data, a process of transmitting the data to a lower node, and at least two messages which are an ACK message and / or a NACK message according to receipt of data from at least one lower node. Is received, the message is transmitted to the upper node at the same time.

  In order to achieve the object of the present invention, according to the second aspect of the present invention, the operation method of the relay station in the wireless communication system using the relay method confirms the occurrence of an error in the data received from the lower node. An ACK message and / or NACK in response to receiving data from the second lower node from at least one lower node, and a step of transmitting the data to the upper node if no error occurs in the data Transmitting at least two messages, which are messages, to the upper node at the same time.

  In order to achieve the object of the present invention, according to a third aspect of the present invention, an operation method of an upper node in a wireless communication system using a relay method is an error occurrence presence / absence message of at least one lower node from a lower relay station. A process of assigning a control channel to be provided, and a process of transmitting the control channel assignment information to the lower relay station.

  In order to achieve the object of the present invention, according to a fourth aspect of the present invention, a relay station apparatus of a wireless communication system using a relay system is provided with data transmitted by an upper node and an error occurrence presence / absence message transmitted by a lower node. When there is no error in the data, the data is transmitted to the lower node, and the data is received from at least one lower node. In response, when at least two messages which are an ACK message and / or a NACK message are received, a transmission unit which transmits the message to an upper node at the same time is provided.

It is a figure which shows the structure of the radio | wireless communications system which uses the multihop relay system by this invention. It is a figure which shows the transmission procedure of the downlink data in the radio | wireless communications system which uses the multihop relay system by embodiment of this invention. 1 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. FIG. 1 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. FIG. It is a figure which shows the transmission procedure of the uplink data in the radio | wireless communications system which uses the multihop relay system by embodiment of this invention. FIG. 2 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for uplink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for uplink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. It is a figure which shows the operation | movement procedure of the relay station for performing ARQ in the radio | wireless communications system which uses the multihop relay system by embodiment of this invention. It is a figure which shows the operation | movement procedure of the base station for performing ARQ in the radio | wireless communications system which uses the multihop relay system by embodiment of this invention. It is a figure which shows the block configuration of the relay station in the radio | wireless communications system which uses the multihop relay system by this invention. It is a figure which shows the transmission procedure of the downlink data in the radio | wireless communications system which uses the multihop relay system by other embodiment of this invention. FIG. 7 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to another embodiment of the present invention. FIG. 7 is a diagram illustrating a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to another embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a specific description of a related known function or configuration may obscure the gist of the present invention, detailed description thereof will be omitted.

  Hereinafter, the present invention describes a technique for transmitting a multiplex control message for an automatic retransmission request (hereinafter referred to as ARQ) in a wireless communication system using a relay method. In the following description, an ACK / NACK message will be described as an example of control messages, but the same applies to other control messages.

  In the following, a radio communication system using an Orthogonal Frequency Division Multiplexing (Orthogonal Frequency Division Multiplexing) system will be described as an example, and the present invention can be similarly applied to communication systems using other multiple access systems.

  In the following description, the wireless communication system will be described on the assumption that it is composed of three hops as shown in FIG. However, the present invention can be similarly applied when the wireless communication system includes two hops or multiple hops.

  FIG. 1 shows a configuration of a wireless communication system using a multi-hop relay system according to an embodiment of the present invention. In the following description, the first relay station 110 means a 1-hop relay station, and the second relay station 120 means a 2-hop relay station.

  In the wireless communication system of FIG. 1, a base station 100 provides a service via a direct link to terminals included in a service area. When the terminal 130 is located outside the service area or outside the service area, the base station 100 provides a service to the terminal 130 via a relay link using the relay stations 110 and 120.

  For example, when transmitting data from the base station 100 to the terminal 130, the base station 100 transmits data to be transmitted to the terminal 130 to the first relay station 110.

  When the first relay station 110 receives data from the base station 100, the first relay station 110 checks whether or not a data error has occurred. For example, the first relay station 110 checks whether an error has occurred using a data error check code (CRC: Cyclic Redundancy Check).

  If there is no error in the data, the first relay station 110 transmits the data to the second relay station 120. In addition, the first relay station 110 transmits an ACK message for data to the base station 100. On the other hand, when an error occurs in the data, the first relay station 110 transmits a NACK message for the data to the base station 100.

  At this time, the first relay station 110 checks whether or not the ACK / NACK message provided from the lower node exists during the previous frame. If there is an ACK / NACK message provided from a lower node, the first relay station 110 transmits an ACK / NACK message for data and an ACK / NACK message provided from the lower node to the base station 100 together. To do. Here, the lower node means a terminal located in the service area of the second relay station 120 or the first relay station 110.

  When data is received from the first relay station 110, the second relay station 120 checks whether or not a data error has occurred. If there is no error in the data, the second relay station 120 transmits the data to the terminal 130. In addition, the second relay station 120 transmits an ACK message for the data to the first relay station 110.

  On the other hand, when an error occurs in the data, the second relay station 120 transmits a NACK message for the data to the first relay station 110.

  At this time, the second relay station 120 checks whether an ACK / NACK message provided from the terminal 130 is present during the previous frame. If the ACK / NACK message provided from the terminal 130 is present, the second relay station 120 combines the ACK / NACK message for data and the ACK / NACK message provided from the terminal 130 together with the first relay station 110. Send to.

  When data is received from the second relay station 120, the terminal 130 confirms whether or not a data error has occurred. If there is no error in the data, the terminal 130 transmits an ACK message for the data to the second relay station 120. On the other hand, when an error occurs in the data, the terminal 130 transmits a NACK message for the data to the second relay station 120.

  As described above, the lower node of the wireless communication system transmits an ACK / NACK message to the upper node depending on whether or not an error occurs in the received data. For example, in the case of the downlink, the node of the wireless communication system transmits an ACK / NACK message to the upper node as shown in FIG. In the case of uplink, the node of the wireless communication system transmits an ACK / NACK message to the upper node as shown in FIG. At this time, the wireless communication system transmits and receives data and an ACK / NACK message in a basic unit of data transmission having a certain size. In the following description, the wireless communication system assumes that the basic unit of data transmission is one frame. At this time, the frame represents a transmission time interval (TTI) that is a basic physical unit of data transmission. That is, the frame represents a processing delay time from when one node receives data and confirms an error until it transmits data and an ACK / NACK message. Hereinafter, in the present invention, the processing delay time is assumed to be one frame, but processing delay times may occur between several frames depending on the capabilities of the base station, the relay station, and the terminal.

  As shown in FIG. 2 below, the wireless communication system transmits an ACK / NACK message for downlink data.

  FIG. 2 shows a downlink data transmission procedure in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention.

  As shown in FIG. 2, when the base station 200 transmits data to the terminal 206, during the i-th frame 210, the base station 200 transmits data 1 to the first relay station 202 (step 231). At this time, the first relay station 202 confirms whether or not an error has occurred for the data 1 received from the base station 200.

  During the (i + 1) th frame 212, the base station 200 transmits data 2 to the first relay station 202 (step 233). At this time, the first relay station 202 confirms whether or not an error has occurred in the data 2 received from the base station 200.

  During the (i + 1) th frame 212, the first relay station 202 transmits an ACK / NACK message for data 1 to the base station 200.

  For example, when an error occurs in data 1, the first relay station 202 transmits a NACK message for data 1 to the base station 200.

  On the other hand, if no error occurs in data 1, first relay station 202 transmits an ACK message for data 1 to base station 200 (step 235). Further, the first relay station 202 transmits data 1 in which no error occurs to the second relay station 204 (step 237). At this time, the second relay station 204 checks whether or not an error has occurred with respect to the data 1 received from the first relay station 202.

  During the (i + 2) th frame 214, the base station 200 transmits data 3 to the first relay station 202 (step 239). The first relay station 202 confirms whether or not an error has occurred in the data 3 received from the base station 200.

  During the (i + 2) -th frame 214, the first relay station 202 transmits an ACK / NACK message for data 2 to the base station 200.

  For example, when an error occurs in data 2, first relay station 202 transmits a NACK message for data 2 to base station 200.

  On the other hand, if no error occurs in data 2, first relay station 202 transmits an ACK message for data 2 to base station 200 (step 241). Also, the first relay station 202 transmits data 2 in which no error occurs to the second relay station 204 (step 243). At this time, the second relay station 204 checks whether or not an error has occurred in the data 2 received from the first relay station 202.

  During the (i + 2) -th frame 214, the second relay station 204 transmits an ACK / NACK message for data 1 to the first relay station 202.

  For example, when an error occurs in data 1, second relay station 204 transmits a NACK message for data 1 to first relay station 202.

  On the other hand, if no error occurs in data 1, the second relay station 204 transmits an ACK message for data 1 to the first relay station 202 (step 245). Further, the second relay station 204 transmits data 1 in which no error occurs to the terminal 206 (step 247). At this time, the terminal 206 confirms whether or not an error has occurred for the data 1 received from the second relay station 204.

  During the (i + 3) th frame 216, the base station 200 transmits data 4 to the first relay station 202 (step 249). At this time, the first relay station 202 confirms whether an error has occurred in the data 4 received from the base station 200.

  During the (i + 3) th frame 216, the first relay station 202 transmits an ACK / NACK message for data 3 to the base station 200. At this time, the first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 2) th frame 214 together with the ACK / NACK message for data 3 to the base station 200 ( Step 253).

  For example, when an error occurs in the data 3, the first relay station 202 transmits a NACK message for requesting retransmission of the data 3 to the base station 200. At this time, the first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 2) th frame 214 to the base station 200 together with the NACK message for data 3.

  On the other hand, if no error occurs in data 3, first relay station 202 transmits an ACK message for data 3 to base station 200 (step 251). At this time, the first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 2) th frame 214 together with the ACK of the data 3 to the base station 200.

  Also, the first relay station 202 transmits data 3 in which no error occurs to the second relay station 204 (step 255). At this time, the second relay station 204 checks whether or not an error has occurred in the data 3 received from the first relay station 202.

  During the (i + 3) th frame 216, the second relay station 204 transmits an ACK / NACK message for data 2 to the first relay station 202.

  For example, when an error occurs in data 2, second relay station 204 transmits a NACK message for data 2 to first relay station 202.

  On the other hand, if no error occurs in data 2, the second relay station 204 transmits an ACK message for data 2 to the first relay station 202 (step 257). Further, the second relay station 204 transmits data 2 in which no error occurs to the terminal 206 (step 259). At this time, the terminal 206 confirms whether or not an error has occurred in the data 2 received from the second relay station 204.

  During the (i + 3) th frame 216, the terminal 206 transmits an ACK / NACK message for data 1 to the second relay station 204.

  For example, when an error occurs in data 1, terminal 206 transmits a NACK message for data 1 to second relay station 204.

  On the other hand, if no error occurs in data 1, the terminal 206 transmits an ACK message for data 1 to the second relay station 204 (step 261).

  During the (i + 4) th frame 218, the base station 200 transmits data 5 to the first relay station 202 (step 263). At this time, the first relay station 202 confirms whether or not an error has occurred in the data 5 received from the base station 200.

  During the (i + 4) th frame 218, the first relay station 202 transmits an ACK / NACK message for data 4 to the base station 200. At this time, the first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 3) th frame 214 together with the ACK / NACK message for data 4 to the base station 200 ( Step 267).

  For example, when an error occurs in data 4, first relay station 202 transmits a NACK message for data 4 to base station 200. At this time, the first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 3) th frame 214 to the base station 200 together with the NACK message for data 4.

  On the other hand, if no error occurs in data 4, first relay station 202 transmits an ACK message for data 4 to base station 200 (step 265). The first relay station 202 transmits the ACK / NACK message provided from the second relay station 204 during the (i + 3) th frame 214 together with the ACK message for the data 4 to the base station 200.

  Further, the first relay station 202 transmits data 4 in which no error occurs to the second relay station 204 (step 269). At this time, the second relay station 204 checks whether or not an error has occurred in the data 4 received from the first relay station 202.

  During the (i + 4) th frame 218, the second relay station 204 transmits an ACK / NACK message for data 3 to the first relay station 202. At this time, the second relay station 204 transmits the ACK / NACK provided from the terminal 206 during the (i + 3) th frame 216 to the first relay station 202 together with the ACK / NACK message for data 3 (step 273). ).

  For example, when an error occurs in the data 3, the second relay station 204 transmits a NACK message for the data 3 to the first relay station 202. At this time, the second relay station 204 transmits the ACK / NACK provided from the terminal 206 to the first relay station 202 together with the NACK message for data 3 during the (i + 3) th frame 216.

  On the other hand, if no error occurs in the data 3, the second relay station 204 transmits an ACK message for the data 3 to the first relay station 202 (step 271). At this time, the second relay station 204 transmits the ACK / NACK provided from the terminal 206 during the (i + 3) th frame 216 to the first relay station 202 together with the ACK message for the data 3 (step 273).

  Further, the second relay station 204 transmits data 3 in which no error occurs to the terminal 206 (step 275). At this time, the terminal 206 confirms whether or not an error has occurred in the data 3 received from the second relay station 204.

  During the (i + 4) th frame 218, the terminal 206 transmits an ACK / NACK message for data 2 to the second relay station 204. For example, when an error occurs in data 2, the terminal 206 transmits a NACK message for data 2 to the second relay station 204.

  On the other hand, when no error occurs in data 2, the terminal 206 transmits an ACK message for data 2 to the second relay station 204 (step 277).

  During the (i + 5) th frame 220, the base station 200 transmits data 6 to the first relay station 202 (step 279). At this time, the first relay station 202 confirms whether or not an error has occurred in the data 6 received from the base station 200.

  During the (i + 5) th frame 220, the first relay station 202 transmits an ACK / NACK message for data 5 to the base station 200. At this time, the first relay station 202 transmits an ACK / NACK message for data 3 and an ACK / NACK message for data 1 of the terminal 206 provided from the second relay station 204 during the (i + 4) th frame 218. The ACK / NACK message for data 5 is transmitted to the base station 200 (steps 283 and 285).

  For example, when an error occurs in the data 5, the first relay station 202 transmits a NACK message for the data 5 to the base station 200. At this time, the first relay station 202 transmits an ACK / NACK message for data 3 and an ACK / NACK message for data 1 of the terminal 206 provided from the second relay station 204 during the (i + 4) th frame 218. The NACK message for data 5 is transmitted to the base station 200.

  On the other hand, if no error occurs in data 5, first relay station 202 transmits an ACK message for data 5 to base station 200 (step 281). At this time, the first relay station 202 transmits an ACK / NACK message for data 3 and an ACK / NACK message for data 1 of the terminal 206 provided from the second relay station 204 during the (i + 4) th frame 218. The ACK message for data 5 is transmitted to the base station 200.

  Further, the first relay station 202 transmits data 5 in which no error occurs to the second relay station 204 (step 287). At this time, the second relay station 204 checks whether or not an error has occurred in the data 5 received from the first relay station 202.

  During the (i + 5) th frame 220, the second relay station 204 transmits an ACK / NACK message for data 4 to the first relay station 202. At this time, the second relay station 204 transmits the ACK / NACK message provided from the terminal 206 during the (i + 4) -th frame 218 to the first relay station 202 together with the ACK / NACK message for the data 4 (step). 291).

  For example, when an error occurs in the data 4, the second relay station 204 transmits a NACK message for the data 4 to the first relay station 202. At this time, the second relay station 204 transmits the ACK / NACK message provided from the terminal 206 during the (i + 4) th frame 218 to the first relay station 202 together with the NACK message for the data 4.

  On the other hand, if no error occurs in data 4, second relay station 204 transmits an ACK message for data 4 to first relay station 202 (step 289). At this time, the second relay station 204 transmits the ACK / NACK message provided from the terminal 206 during the (i + 4) th frame 218 to the first relay station 202 together with the ACK message for the data 4.

  Further, the second relay station 204 transmits data 4 with no error to the terminal 206 (step 293). At this time, the terminal 206 confirms whether or not an error has occurred in the data 4 received from the second relay station 204.

  During the (i + 5) th frame 220, the terminal 206 transmits an ACK / NACK message for data 3 to the second relay station 204. For example, when an error occurs in the data 3, the terminal 206 transmits a NACK message for the data 3 to the second relay station 204.

  On the other hand, when no error occurs in the data 3, the terminal 206 transmits an ACK message for the data 3 to the second relay station 204 (step 295).

  As described above, the first relay station 202, the second relay station 204, and the terminal 206 in the wireless communication system transmit an ACK / NACK message for data provided from the upper node to the upper node. At this time, the first relay station 202, the second relay station 204, and the terminal 206 transmit an ACK / NACK message using resources allocated from the upper node. For example, the upper node allocates a control channel for the ACK / NACK message to the first relay station 202, the second relay station 204, and the terminal 206.

  Further, when there is an ACK / NACK message provided from the lower node, the relay stations 202 and 204 transmit both the ACK / NACK message and the ACK / NACK message for the data provided from the upper node to the upper node. For example, the first relay station 202 uses both the ACK / NACK message for the data provided from the base station 200 in the (i + 3) th frame 216 and the ACK / NACK message provided from the second relay station 204 together. Send to. In addition, the second relay station 204 combines the ACK / NACK message for the data provided from the first relay station 202 and the ACK / NACK message provided from the terminal 206 in the (i + 4) th frame 218 together with the first relay station. 202.

  That is, the relay station transmits a multiple ACK / NACK message for data provided during different time frames between the base station and the terminal to an upper node (eg, base station or upper relay station).

  Therefore, the upper node allocates a control channel for the multiple ACK / NACK message to the lower node as shown in FIGS. 3 and 4 below so that the lower node can transmit the multiple ACK / NACK message. Here, FIG. 3 below will be described with an example in which the base station allocates a control channel for a multiple ACK / NACK message to the relay station 1.

  3 and 4 show a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. Here, FIG. 3 and FIG. 4 will be described by taking an example of the frame structure of an IEEE (Institut of Electrical and Electronics Engineers) 802.16 system.

  As shown in FIGS. 3 and 4, the base station allocates multiple channels to the relay station 1 so that the relay station 1 can transmit a plurality of ACK / NACK messages.

  As shown in FIG. 3, the base station allocates multiple channels for ACK / NACK messages to the relay station 1 using an uplink map (UL-MAP) of the downlink subframe 300. Therefore, the relay station 1 can transmit the ACK / NACK message of data provided from the base station and the ACK / NACK message provided from the relay station 2 or the terminal to the base station at a time using multiple channels. .

  In order to allocate multiple channels for ACK / NACK messages to the relay station 1, the base station configures information elements (Information Elements) and includes them in the uplink map. At this time, the information element includes unique identifiers (for example, CID (Connection ID) and adaptive modulation (MCS) level information) of the relay station 1, the relay station 2, and the terminal.

  Further, the base station configures the information element so as to include the start point and end point of the area for the ACK / NACK message for each unique identifier. For example, the base station assigns a HARQ (Hybrid ARQ) ACK area (Region) allocation information element (Allocation) information element defined in the IEEE 802.16 standard to allocate multiple channels for ACK / NACK messages to the relay station 1. Information Element) can be used as an information element. At this time, the information element represents the start point and end point of the ACK / NACK message for each unique identifier in the frequency domain in units of subchannels and in the time domain in units of OFDM symbols.

  The relay station 1 transmits a multiple ACK / NACK message to the base station using the region of the uplink frame assigned by the base station for each unique identifier in the uplink map. For example, the relay station 1 transmits an ACK / NACK message of data provided from the base station according to the ACK region scheduling information 301 assigned to the unique identifier of the relay station 1 in the first region 311 of the uplink subframe 310. To the base station. Also, the relay station 1 transmits the ACK / NACK message provided from the relay station 2 to the base station via the second region 313 according to the ACK region scheduling information 303 assigned to the unique identifier of the relay station 2. . In addition, the relay station 1 transmits the terminal ACK / NACK message provided from the relay station 2 to the base station via the third area 315 according to the terminal ACK area scheduling information 305 assigned to the terminal unique identifier. To do.

  As described above, the base station assigns to the relay station 1 a control channel for transmitting an ACK / NACK message according to the unique identifiers of the relay station 1, the relay station 2, and the terminal via the uplink map. At this time, the base station defines a separate message or information element so that the relay station 1 can reliably grasp the functions of the relay station 2 and the unique identifier of the terminal included in the uplink map, and the relay station 2 And informs the relay station 1 of the use of the unique identifier of the terminal.

  As shown in FIG. 4, the base station allocates multiple channels for ACK / NACK messages to the relay station 1 using an uplink map (UL-MAP) of the downlink subframe 320. Therefore, the relay station 1 transmits the ACK / NACK message of data provided from the base station and the ACK / NACK message provided from the relay station 2 or the terminal to the base station at a time using multiple channels. it can.

  At this time, between the base station and the relay station 1, it is promised in advance which node's ACK / NACK message is transmitted according to each frame. For example, in the (i + 5) -th frame in FIG. 2, the base station determines that the relay station 1 receives an ACK / NACK message for data 5, an ACK / NACK message for relay station 2 for data 3, and an ACK / NACK for the terminal for data 1 Know to send a message. At this time, the base station promises to the relay station 1 which node's ACK / NACK message the relay station 1 transmits for each frame using broadcast information or a separate control channel.

  Further, the base station configures an uplink map including information elements for the ACK / NACK message of the relay station so that the relay station 1 can transmit multiple ACK / NACK messages. At this time, the information element for the ACK / NACK message of the relay station includes start point information and end point information of the multiple ACK / NACK message. For example, the allocation information element of the HARQ ACK area of the IEEE 802.16 system can be used as an information element for the ACK / NACK message. At this time, the start point and end point of the ACK / NACK message in the uplink frame are expressed in units of subchannels in the frequency domain and in units of OFDM symbols in the time domain.

  Therefore, the relay station 1 transmits a multiple ACK / NACK message to the base station via the region of the uplink frame allocated from the base station via the uplink map. At this time, the relay station 1 transmits an ACK / NACK message for a node promised in advance with the base station to the base station. For example, the relay station 1 transmits the data ACK / NACK message 331 provided from the base station to the region allocated by the base station via the ACK region scheduling information 321 of the uplink map, and the ACK / NACK provided from the relay station 2. The NACK message 333 and the terminal ACK / NACK message 335 provided from the relay station 2 are transmitted to the base station.

  As another embodiment, the relay station 1 transmits multiple ACK / NACK messages according to the data transmission order. That is, in the case of the (i + 5) -th frame 220 in FIG. 2, the first relay station 202 transmits an ACK / NACK message of the terminal 206 for the data 1 having a fast transmission order via the first region 331. Next, the first relay station 202 transmits the ACK / NACK message of the second relay station 204 for the data 3 via the second area 333. Finally, the first relay station 202 transmits an ACK / NACK message for data 5 through the third region 335. Also, the first relay station 202 can sequentially transmit ACK / NACK messages for data with a late transmission order.

  Also, the base station and the relay station 1 promise in advance the transmission order of the ACK / NACK messages included in the multiple ACK / NACK messages. Therefore, the base station knows which node's ACK / NACK message for which data the multiple ACK / NACK message transmitted by the relay station 1 for each frame.

  Therefore, the base station does not have to separately assign an offset value for distinguishing multiple ACK / NACK messages transmitted by the relay station 1.

  As described above, the relay station 1 transmits the ACK / NACK messages of the relay station 1, the relay station 2, and the terminal to the base station via the multiplex control channel assigned by the base station. At this time, between the base station and the relay station 1, it must be promised what ACK / NACK message for the data is transmitted via the multiple control channel.

  Therefore, the base station promises in advance an ACK / NACK message of data to be transmitted to the relay station 1 through the multiple control channel using broadcast information or a separate control channel. In this case, the relay station 1 responds to the ACK / NACK message information of the data transmitted through the multiplex control channel promised with the base station, and the ACK / NACK of itself and lower nodes at each transmission time point through the multiplex control channel. It can be recognized how many frames ago the message is an ACK / NACK message for data transmitted and received with reference to the transmission time point.

  In the unlikely event that the base station does not promise in advance data to be transmitted via the multiple control channel with the relay station 1 using a broadcast message or a separate control channel, the base station may provide an information element for the ACK / NACK message. It is also possible to transmit ACK / NACK message information of data to be transmitted through the multiple control channel to the relay station 1.

  In the above-described embodiment, the wireless communication system configures the uplink map to include the scheduling information for the ACK / NACK message region in the uplink subframe of the same frame via the downlink subframes 300 and 320. In another embodiment, the wireless communication system may update the uplink map to include the scheduling information for the ACK / NACK message region in the uplink subframe that is positioned next to the number of frames via the downlink subframes 300 and 320. Constitute.

  Next, as shown in FIG. 5 below, the wireless communication system transmits an ACK / NACK message for uplink data.

  FIG. 5 shows a procedure for transmitting uplink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. Here, description will be made assuming that base station 400 receives data 1 and data 2 from terminal 406.

  As shown in FIG. 5, when data 1 and data 2 are transmitted from the terminal 406 to the base station 400, the base station 400 transmits scheduling information for the data 1 to the first relay station 402 during the i-th frame 410. Transmit (step 431).

  During the (i + 1) th frame 412, the base station 400 transmits scheduling information for data 2 to the first relay station 402 (step 433).

  During the (i + 1) th frame 412, the first relay station 402 transmits scheduling information for data 1 to the second relay station 404 (step 435).

  During the (i + 2) -th frame 414, the first relay station 402 transmits scheduling information for data 2 to the second relay station 404 (step 437).

  During the (i + 2) -th frame 414, the second relay station 404 transmits scheduling information for data 1 to the terminal 406 (step 439).

  During the (i + 3) -th frame 416, the second relay station 404 transmits scheduling information for data 2 to the terminal 406 (step 441).

  During the (i + 3) th frame 416, the terminal 406 transmits data 1 to the second relay station 404 according to the scheduling information of data 1 provided from the second relay station 404 (step 443). At this time, the second relay station 404 confirms whether or not an error has occurred for the data 1 received from the terminal 406.

  During the (i + 4) th frame 418, the second relay station 404 transmits an ACK / NACK message according to whether or not an error has occurred in the data 1 provided from the terminal 406. For example, when an error occurs in data 1, the second relay station 404 transmits a NACK message to the first relay station 402 and the terminal 406.

  On the other hand, if an error does not occur in data 1, second relay station 404 transmits data 1 and an ACK message for data 1 to first relay station 402 (step 445). At this time, the first relay station 402 confirms whether or not an error has occurred in the data 1 received from the second relay station 404.

  The second relay station 404 transmits an ACK message for data 1 to the terminal 406 (step 447).

  During the (i + 4) th frame 418, the terminal 406 transmits data 2 to the second relay station 404 according to the scheduling information of the data 2 provided from the second relay station 404 (step 449). At this time, the second relay station 404 confirms whether or not an error has occurred in the data 2 received from the terminal 406.

  During the (i + 5) -th frame 420, the first relay station 402 transmits an ACK / NACK message depending on whether or not an error has occurred in the data 1 provided from the second relay station 404. For example, when an error occurs in data 1, first relay station 402 transmits a NACK message for data 1 to base station 400 and second relay station 402.

  At this time, the first relay station 404 transmits an ACK / NACK message for data 1 provided from the second relay station 404 to the base station 400 during the (i + 4) th frame 418 (step 453).

  On the other hand, if no error occurs in data 1, first relay station 402 transmits data 1 and an ACK message for data 1 to base station 400 (step 451).

  At this time, the first relay station 402 transmits an ACK / NACK message for data 1 provided from the second relay station 404 to the base station 400 during the (i + 4) th frame 418 (step 453).

  Thereafter, the first relay station 402 transmits an ACK message for data 1 to the second relay station 404 (step 455).

  During the (i + 5) th frame 420, the second relay station 404 transmits an ACK / NACK message according to whether or not an error has occurred in the data 2 provided from the terminal 406. For example, when an error occurs in data 2, second relay station 404 transmits a NACK message for data 2 to first relay station 402 and terminal 406.

  On the other hand, if an error does not occur in data 2, second relay station 404 transmits data 2 and an ACK message for data 2 to first relay station 402 (step 457). At this time, the first relay station 402 confirms whether or not an error has occurred in the data 2 received from the second relay station 404.

  Thereafter, the second relay station 404 transmits an ACK message for data 2 to the terminal 406 (step 459).

  During the (i + 6) th frame 422, the first relay station 402 transmits an ACK / NACK message according to whether or not an error has occurred in the data 2 provided from the second relay station 404. For example, when an error occurs in data 2, first relay station 402 transmits a NACK message for data 2 to base station 400 and second relay station 404.

  At this time, the first relay station 402 transmits an ACK / NACK message for data 2 provided from the second relay station 404 to the base station 400 during the (i + 5) th frame 420 (step 463).

  On the other hand, if no error occurs in data 2, first relay station 402 transmits data 2 and an ACK message for data 2 to base station 400 (step 461).

  At this time, the first relay station 402 transmits an ACK / NACK message for data 2 provided from the second relay station 404 to the base station 400 during the (i + 5) th frame 420 (step 463).

  Thereafter, the first relay station 402 transmits an ACK message for data 2 to the second relay station 404 (step 465).

  As described above, in the wireless communication system, the first relay station 402, the second relay station 404, and the terminal 406 transmit an ACK / NACK message for uplink data to the upper node and the lower node. At this time, the first relay station 402, the second relay station 404, and the terminal 406 transmit an ACK / NACK message via the control channel provided from the upper node.

  Further, when there is an ACK / NACK message provided from the lower node, the relay stations 402 and 404 transmit both the ACK / NACK message and the ACK / NACK message for the data provided from the lower node to the upper node. For example, the first relay station 402 receives the ACK / NACK message of the data provided from the second relay station 404 in the (i + 5) th frame 420 and the ACK of the second relay station 404 provided from the second relay station 404. / NACK message is transmitted to base station 400 together.

  That is, the relay station transmits a multiple ACK / NACK message for uplink data provided during different time frames between the base station and the terminal to an upper node (eg, base station or upper relay station). .

  Therefore, the upper node allocates a control channel for the multiple ACK / NACK message to the lower node as shown in FIGS. 6 and 7 so that the lower node can transmit the multiple ACK / NACK message. Here, FIG. 6 and FIG. 7 described below will be described with an example in which the base station allocates a control channel for multiple ACK / NACK messages to the relay station 1.

  6 and 7 show a frame structure for transmitting ACK / NACK scheduling information for uplink data in a wireless communication system using a multi-hop relay scheme according to an embodiment of the present invention. Here, FIGS. 6 and 7 will be described by taking the frame structure of the IEEE 802.16 system as an example.

  Referring to FIGS. 6 and 7, the base station allocates multiple channels to the relay station 1 so that the relay station 1 can transmit a plurality of ACK / NACK messages for uplink data.

  First, as illustrated in FIG. 6, the base station allocates multiple channels for ACK / NACK messages to the relay station 1 using an uplink map (UL-MAP) of the downlink subframe 500. Therefore, the relay station 1 can transmit the ACK / NACK message for uplink data and the ACK / NACK message provided from the relay station 2 to the base station by using the multiple channels provided from the base station.

  In order to allocate multiple channels for ACK / NACK messages to the relay station 1, the base station configures information elements (Information Elements) and includes them in the uplink map. At this time, the information element includes unique identifiers (for example, CID (Connection ID) and adaptive modulation (MCS) level information) of the relay station 1, the relay station 2, and the terminal.

  Also, the base station configures the information element to include a start point and an end point for the ACK / NACK message for each unique identifier. For example, the base station can use the allocation information element of the HARQ ACK area of the IEEE 802.16 system as an information element in order to allocate multiple channels for ACK / NACK messages to the relay station 1. At this time, the allocation information element of the HARQ ACK area may be newly defined for resource allocation for uplink data.

  At this time, the information element represents the start point and end point of the ACK / NACK message for each unique identifier in the frequency domain in units of subchannels and in the time domain in units of OFDM symbols.

  The relay station 1 transmits a multiple ACK / NACK message to the base station using an uplink frame region assigned to each unique identifier by the base station via the uplink map. For example, the relay station 1 transmits an ACK / NACK message of the data provided from the relay station 2 in the uplink subframe 510 according to the ACK area scheduling information 501 assigned through the unique identifier of the relay station 1. It transmits to a base station via 1 area | region 511. FIG. In addition, the relay station 1 sends the ACK / NACK message provided from the relay station 2 via the second area 515 to the base station according to the ACK area scheduling information 505 assigned via the unique identifier of the relay station 2. Send.

  As described above, the base station allocates to the relay station 1 a control channel for transmitting an ACK / NACK message corresponding to the unique identifiers of the relay station 1 and the relay station 2 via the uplink map. At this time, the base station defines a separate message so that the relay station 1 can surely understand the functions of the unique identifiers of the relay station 2 and the terminal included in the uplink map. Inform the relay station 1 of the use of the connection identifier.

  As illustrated in FIG. 7, the base station allocates multiple channels for ACK / NACK messages to the relay station 1 using an uplink map (UL-MAP) of the downlink subframe 520. Therefore, the relay station 1 can transmit the ACK / NACK message for uplink data and the ACK / NACK message provided from the relay station 2 to the base station at a time using multiple channels.

  At this time, between the base station and the relay station 1, it is promised in advance which node's ACK / NACK message is transmitted according to each frame. For example, in the (i + 5) th frame 420 of FIG. 5, the base station knows that the relay station 1 transmits an ACK / NACK message for data 1 and an ACK / NACK message of the relay station 2 for data 1. . At this time, the base station promises to the relay station 1 as to which node's ACK / NACK message the relay station 1 transmits for each frame using broadcast information or a separate control channel.

  The base station configures information elements including a start point and an end point for multiple ACK / NACK messages so that the relay station 1 can transmit a plurality of ACK / NACK messages, and includes the information elements in the uplink map. For example, the base station configures an information element for an ACK / NACK message using an allocation information element of the HARQ ACK area of the IEEE 802.16 system. At this time, the start point and the end point of the ACK / NACK message in the uplink frame are expressed in units of subchannels in the frequency domain and in units of OFDM symbols in the time domain.

  The relay station 1 uses the region of the uplink frame 530 allocated from the base station using the ACK region scheduling information 521 included in the uplink map, and transmits a plurality of ACK / NACK messages 531 and 533 to the base station. Send to. That is, the relay station 1 transmits an ACK / NACK message for a node promised in advance with the base station to the base station via the uplink frame region assigned by the base station.

  As described above, the relay station 1 transmits the ACK / NACK messages of the relay station 1 and the relay station 2 to the base station via the multiple control channel assigned by the base station. At this time, it must be promised between the base station and the relay station 1 what ACK / NACK message for the data is to be transmitted through the multiple control channel.

  Therefore, the base station promises an ACK / NACK message of data to be transmitted to the relay station 1 via the multiple control channel using broadcast information or a separate control channel. In this case, the relay station 1 responds to the ACK / NACK message information of the data transmitted through the multiplex control channel promised with the base station, and the ACK / NACK of itself and the lower nodes at each transmission time point through the multiplex control channel. It can be recognized how many frames ago the message is an ACK / NACK message for data transmitted and received with respect to the transmission time point.

  In the unlikely event that the base station does not promise in advance data to be transmitted through the relay station 1 and the multiple control channel using a broadcast message or a separate control channel, the base station may use the information element for the ACK / NACK message. ACK / NACK message information of data to be transmitted through the multiple control channel can be transmitted to the relay station 1.

  Hereinafter, an operation method of the relay station for transmitting an ACK / NACK message for retransmission in the wireless communication system will be described.

  FIG. 8 shows an operation procedure of the relay station for performing ARQ in the wireless communication system using the multi-hop relay system according to the embodiment of the present invention.

  As shown in FIG. 8, first, the relay station checks in step 601 whether data is received. For example, in the case of the downlink, the relay station confirms whether data is received from an upper node. On the other hand, in the case of uplink, the relay station checks whether data is received from a lower node.

  If data is received, the relay station proceeds to step 603 to check whether an error occurs in the received data.

  If an error occurs in the received data, the relay station proceeds to step 607 and checks whether error occurrence information is received from the lower node. Here, the error occurrence information represents an ACK message or a NACK message. For example, in the case of the downlink, as shown in FIG. 2, the relay station checks whether an ACK / NACK message is received from a lower node during the previous frame. On the other hand, in the case of uplink, as shown in FIG. 5, the relay station checks whether an ACK / NACK message is received from a lower node during the previous frame.

  On the other hand, if no error occurs in the received data, the relay station proceeds to step 605 and transmits the received data to the upper node or the lower node. For example, in the case of downlink, the relay station transmits data provided from the upper node to the lower node. On the other hand, in the uplink, the relay station transmits data provided from the lower node to the upper node.

  After transmitting the received data, the relay station proceeds to step 607 and confirms whether error occurrence information has been received from the lower node. For example, in the case of the downlink, as shown in FIG. 2, the relay station checks whether an ACK / NACK message is received from a lower node during the previous frame. On the other hand, in the case of uplink, as shown in FIG. 5, the relay station checks whether an ACK / NACK message is received from a lower node during the previous frame.

  If the error occurrence information is received from the lower node, the relay station proceeds to step 609 and transmits the error occurrence information of the received data and the error occurrence information provided from the lower node to the upper node. At this time, the relay station promises a node and data that transmit error occurrence information to the corresponding frame via broadcast information or a separate control channel and data to the upper node. Therefore, the relay station transmits error occurrence information for data promised to the upper node to the upper node via the multiple control channel provided from the upper node.

  On the other hand, when the error occurrence information is not received from the lower node, the relay station proceeds to step 611 and transmits the error occurrence information of the received data to the upper node via the control channel provided from the upper node.

  Thereafter, the relay station ends this algorithm.

  Hereinafter, an operation method of an upper node that allocates multiple control channels for a relay station in a wireless communication system to transmit multiple ACK / NACK messages will be described. Here, FIG. 9 below promises data in which the upper node transmits error occurrence information according to the transmission time with the next hop relay station via broadcast information or a separate control channel. Hereinafter, a method for the upper node to allocate a multiple control channel for the relay station to transmit error occurrence information to the corresponding data will be described.

  FIG. 9 shows an operation procedure of the base station for performing ARQ in the radio communication system using the multi-hop relay scheme according to the embodiment of the present invention. Here, FIG. 9 will be described by taking the base station as an example of the upper nodes, but the upper relay station operates in the same manner.

  As shown in FIG. 9, first, in step 701, the base station determines whether to assign a control channel for the ACK / NACK control message to the next hop relay station for each node as shown in FIG. 3 or FIG. Check.

  If the control channel is allocated to each node, the base station proceeds to step 703 and confirms the unique identifier of the node that transmits the ACK / NACK message to itself via the next hop relay station. Here, the unique identifier means a CID.

  After confirming the unique identifier of the node, the base station proceeds to step 705 and allocates a control channel for the ACK / NACK message for each unique identifier.

  Thereafter, the base station proceeds to step 707 and generates a multiple control channel including control channel information assigned for each unique identifier. For example, the base station generates an information element including control channel information allocated for each unique identifier.

  After generating the multiple control channel, the base station proceeds to step 709 and transmits the multiple control channel to the next hop relay station. That is, the base station configures an uplink map including an information element including control channel information allocated for each unique identifier, and transmits the uplink map to the next hop relay station. For example, the base station transmits control channel information assigned to each unique identifier as shown in FIG. 3 or FIG. 6 to the next hop relay station.

  On the other hand, if the node-specific control channel is not allocated in step 701, the base station proceeds to step 711 and selects a node for providing an ACK / NACK message via the next hop relay station for each frame. decide.

  After determining the node, the base station proceeds to step 713 and transmits information for the determined node to the next hop relay station. For example, the base station transmits information on the determined node to the next hop relay station using broadcast information or a separate control channel.

  After transmitting the information for the node, the base station proceeds to step 715 and assigns a multiple control channel for providing an ACK / NACK message for the determined node to the next hop relay station.

  After assigning the multiple control channel, the base station proceeds to step 709 and transmits the multiple control channel to the next hop relay station. For example, as shown in FIG. 4 or FIG. 7, the base station transmits multiple control channel information to the next hop relay station. At this time, the base station includes only the start point and end point information of the multiple control channel. Therefore, the relay station assigned the multiple control channel from the base station transmits an ACK / NACK message for the node promised to the base station in step 713 on the multiple control channel according to a certain order and transmits it to the base station.

  Thereafter, the base station ends this algorithm.

  Hereinafter, a block configuration of a relay station for transmitting an ACK / NACK message for retransmission in the wireless communication system will be described.

  FIG. 10 shows a block configuration of a relay station in a wireless communication system using the multi-hop relay system according to the present invention. In the following description, it is assumed that the transmitting unit 800 and the receiving unit 820 use different antennas. However, the transmitting unit 800 and the receiving unit 820 may use one antenna.

  As shown in FIG. 10, the relay station includes a transmission unit 800, a reception unit 820, an ARQ control unit 840 shared by the transmission unit 800 and the reception unit 820, an ARQ state unit 850, an ARQ timer 860, and a channel estimator 870. Prepare.

  First, the transmission unit 800 includes a data generation unit 801, a channel encoder 803, a CRC generator 805, a modulator 807, an IFFT (Inverse Fast Fourier Transform) calculator 809, and an RF processor 811.

  The data generation unit 801 collects the data stored in the data queue 813 and the control message generated from the message generator 817 in an SDU (Service Data Unit) generator 815, and stores one piece of data for transmission in the physical layer. Generate. Here, the message generator 817 generates an ACK message if there is no error in the data received via the receiving unit 820. On the other hand, the message generator 817 generates a NACK message when an error occurs in the data. At this time, if there is an ACK / NACK message provided from the lower node, the message generator 817 can transmit both the ACK / NACK message for the data received by the relay station and the ACK / NACK message provided from the lower node. So that the message is generated.

  The channel encoder 803 encodes the data provided from the data generation unit 801 according to the corresponding modulation level (eg, MCS level). The CRC generator 805 generates an error detection code, adds it to the data provided from the channel encoder 803, and outputs it.

  The modulator 807 modulates the data provided from the CRC generator 805 according to a corresponding modulation level (eg, MCS level) and outputs the modulated data.

  The IFFT calculator 809 performs inverse fast Fourier transform on the frequency domain data provided from the modulator 807 to convert it into a time domain signal.

  The RF processor 811 up-converts the baseband signal provided from the IFFT calculator 809 into a radio frequency signal and outputs the signal to an upper node or a lower node via an antenna.

  Next, the receiving unit 820 includes an RF processor 821, an FFT (Fast Fourier Transform) calculator 823, a demodulator 825, a CRC remover 827, a channel decoder 829, and a data processor 831.

  The RF processor 821 frequency-modulates a high-frequency signal received from an upper node or lower node via an antenna to a baseband signal and outputs the baseband signal.

  The FFT calculator 823 performs fast Fourier transform on the time domain signal provided from the RF processor 821 to convert it into a frequency domain signal.

  The demodulator 825 demodulates and outputs the signal provided from the FFT calculator 823 according to the corresponding modulation level. At this time, demodulator 825 outputs the demodulated signal to CRC remover 827 and channel estimator 870.

  The CRC remover 827 checks the error detection code of the signal provided from the demodulator 825 and determines whether or not a signal error has occurred. At this time, the CRC remover 827 removes the error detection code from the signal provided from the demodulator 825.

  The channel decoder 829 decodes and outputs the error-free signal provided from the CRC remover 827 according to the corresponding modulation level.

  The SDU processor 835 of the data processing unit 831 separates the data and the control message from the physical layer signal provided from the channel decoder 829. Thereafter, the SDU processor 835 provides the data to the second data queue 837 for storage, and the control message is provided to the message processor 833 for decoding and confirmation. Here, the first data queue 813 and the second data queue 827 may be the same data queue.

  The message processing unit 833 confirms the ACK / NACK message received from the lower node. In addition, the message processing unit 833 confirms the multiplex control channel information for the ACK / NACK message provided from the upper node and provides it to the transmission unit 800.

  The ARQ state unit 850 manages the ARQ state for the retransmitted data. The ARQ timer 860 manages a valid time for retransmission of the relay station.

  The ARQ controller 840 controls the overall operation of the ARQ of the relay station in conjunction with the ARQ state unit 850 and the ARQ timer 860. At this time, the ARQ controller 840 controls retransmission while communicating with the data generation unit 801, the channel encoder 803, and the CRC generator 805 of the transmission unit 800. For example, when a retransmission request is received from a lower node via the receiving unit 820, the ARQ controller 840 controls the transmitting unit 800 to transmit a retransmission request signal to the upper node. When retransmission scheduling information is received from the upper node, the ARQ controller 840 encodes the data provided from the upper node stored in the data queue 813 according to the channel state, and inserts an error detection code. Then, control is performed so as to be retransmitted to the subordinate node requesting the retransmission.

  At this time, the ARQ controller 840 performs control so that the transmission unit 800 can transmit a multiple ACK / NACK message. For example, the ARQ controller 840 controls the transmission unit 800 so that an ACK / NACK message for data received by the relay station and an ACK / NACK message provided from the lower node can be transmitted to the upper node together.

  Further, the ARQ controller 840 controls retransmission while communicating with the data processing unit 831, the channel decoder 829, and the CRC remover 827 of the receiving unit 820. For example, when an error occurs in the received data in the CRC remover 827, the ARQ controller 840 controls the message generator 817 to generate a NACK control message to be transmitted to the base station.

  In addition, if the ARQ controller 840 is provided with an expiration time end message from the ARQ timer 860 during the retransmission procedure, the ARQ controller 840 ends the retransmission procedure.

  Hereinafter, another link configuration in the downlink of the wireless communication system using the multi-hop relay scheme will be described as an example. In the following description, the wireless communication system assumes that the basic unit of data transmission is one frame. Here, the frame is determined in consideration of downlink data delay at the relay station (DL burst processing Delay), ACK transmission delay at the terminal (ACK feedback delay), and ACK transmission delay at the relay station (ACK forwarding Delay). Assumed physical frame.

  FIG. 11 illustrates a downlink data transmission procedure in a wireless communication system using a multi-hop relay scheme according to another embodiment of the present invention.

  As shown in FIG. 11, the wireless communication system includes a base station 900, a first relay station 902, a first terminal 904, a second relay station 906, and a second terminal 908. Here, the first terminal 904 represents at least one terminal that communicates with the first relay station 902, and the second terminal 908 represents at least one terminal that communicates with the second relay station 906.

  First, when transmitting HARQ data from the base station 900 to the second terminal 908, the base station 900 transmits scheduling information 1 and data 1 for transmitting data 1 to the second terminal 908 during the i-th frame 910. Is transmitted to the first relay station 902 (step 931). For example, the scheduling information represents HARQ downlink map information defined in the IEEE 802.16 standard.

  When receiving the scheduling information 1 and the data 1 from the base station 900, the first relay station 902 transmits the scheduling information 1 and the data 1 to the second relay station 906 during the (i + 1) th frame 912. (Step 933). At this time, it is assumed that no error has occurred in data 1.

  When receiving the scheduling information 1 and the data 1 from the first relay station 902, the second relay station 906 transmits the scheduling information 1 and the data 1 to the second terminal 908 during the (i + 2) th frame 914. (Step 937). At this time, it is assumed that no error has occurred in data 1.

  When the second terminal 908 receives the scheduling information 1 and the data 1 from the second relay station 906, the second terminal 908 confirms an ACK transmission section (ACK Allocation region) for transmitting an ACK / NACK message via the scheduling information 1.

  Thereafter, the second terminal 908 transmits an ACK / NACK message for data 1 to the second relay station 906 via the ACK transmission interval during the (i + 3) th frame 916 (step 941).

  When the second relay station 906 receives the ACK / NACK message for data 1 from the second terminal 908, the second relay station 906 transmits the ACK / NACK message of the terminal 908 for data 1 during the (i + 4) th frame 918 to the first relay station. Transmit to 902 (step 945).

  When receiving the ACK / NACK message of the second terminal 908 for the data 1 from the second relay station 906, the first relay station 902 receives the ACK of the second terminal 908 for the data 1 during the (i + 5) th frame 920. / NACK message is transmitted to the base station 900 (step 947).

  Next, when transmitting HARQ data from the base station 900 to the first terminal 904, the base station 900 includes scheduling information 2 for transmitting data 2 to the first terminal 904 during the (i + 2) th frame 914. Data 2 is transmitted to the first relay station 902 (step 935). For example, the scheduling information represents HARQ downlink map information defined in the IEEE 802.16 standard.

  When receiving the scheduling information 2 and the data 2 from the base station 900, the first relay station 902 transmits the scheduling information 2 and the data 2 to the first terminal 904 during the (i + 3) th frame 916 ( Step 939). At this time, it is assumed that no error has occurred in data 2.

  When receiving the scheduling information 2 and the data 2 from the first relay station 902, the first terminal 904 confirms an ACK transmission section (ACK Allocation region) for transmitting an ACK / NACK message via the scheduling information 2.

  Thereafter, the first terminal 904 transmits an ACK / NACK message for data 2 to the first relay station 902 through the ACK transmission interval during the (i + 4) th frame 918 (step 943).

  When the ACK / NACK message for data 2 is received from the first terminal 904, the first relay station 902 transmits the ACK / NACK message of the first terminal 904 for data 2 during the (i + 5) th frame 920 to the base station. 900.

  As described above, the first relay station 902 receives the ACK / NACK message for the data 2 transmitted to the first terminal 904 and the ACK / NACK for the data 1 transmitted to the second terminal 908 during the (i + 5) th frame. The message is transmitted to the base station 900. That is, the relay station transmits multiple ACK / NACK messages for data transmitted from different time frames between the base station and the terminal to an upper node (eg, base station or upper relay station).

  Therefore, the upper node allocates a control channel for the multiple ACK / NACK message to the lower node as shown in FIG. 10 so that the lower node can transmit the multiple ACK / NACK message. Here, FIG. 12 and FIG. 13 below will be described with an example in which the base station allocates a control channel for the multiple ACK / NACK message to the relay station 1.

  12 and 13 illustrate a frame structure for transmitting ACK / NACK scheduling information for downlink data in a wireless communication system using a multi-hop relay scheme according to another embodiment of the present invention.

  As shown in FIGS. 12 and 13, the base station allocates multiple channels so that the relay station 1 can transmit ACK / NACK messages for downlink data to the multiple channels.

  First, as shown in FIG. 12, the base station uses the uplink map (UL-MAP) of the downlink subframe 1000 so that the ACK transmission area for terminal 1 and the ACK transmission area for terminal 2 are different from each other. And transmitted to the relay station 1. At this time, the base station configures the resource allocation information to be transmitted to the relay station 1 according to the allocation information for the terminal 1 and the allocation information for the terminal 2.

  Relay station 1 uses ACK / NACK message 1011 for terminal 1 using different areas of uplink subframe 1010 according to resource allocation information allocated from the base station via ACK area scheduling information 1001 and 1003. An ACK / NACK message 1013 for terminal 2 is transmitted to the base station.

  Next, as shown in FIG. 13, the base station uses the ACK area scheduling information 1021 of the uplink map of the downlink subframe 1020 to increase the ACK transmission areas 1031 and 1033 of the terminal 1 and the terminal 2 to one up. It is allocated to the link frame area and transmitted to the relay station 1. In this case, the wireless communication system can reduce overhead according to downlink scheduling as compared with FIG.

  However, as shown in FIG. 13, when the ACK transmission area is assigned, the base station can distinguish the ACK information of the terminal 1 and the terminal 2 by one ACK transmission area assigned to the uplink subframe area. Information must be transmitted to the relay station 1. For example, the base station includes the ACK / NACK message end point information of the previously provided terminal or the next assigned terminal ACK / NACK message start point information in the scheduling information for the ACK transmission area.

  As another embodiment, the relay station 1 transmits the ACK / NACK message of the terminal according to the transmission order of data promised with the base station. For example, as illustrated in FIG. 11, the base station transmits data 1 during the i-th frame 910 and then transmits data 2 during the (i + 2) -th frame 914. Therefore, the relay station 1 first transmits an ACK / NACK message of the terminal 2 for the data 1 transmitted first from the base station during the (i + 5) th frame 920. Next, relay station 1 transmits an ACK / NACK message of terminal 2 for data 2.

  At this time, relay station 1 can transmit the ACK / NACK message of terminal 1 for data 1 after transmitting the ACK / NACK message of terminal 2 for data 2.

  In the unlikely event, data 1 and data 2 are transmitted from the base station during the same downlink subframe, and an ACK / NACK message for data 1 and data 2 is transmitted from the relay station 1 during the same uplink subframe. Also in this case, the relay station 1 can sequentially transmit ACK / NACK messages in accordance with the order of data scheduled and transmitted from the base station.

  Therefore, the base station may notify only the region information of the uplink frame to which the relay station 1 assigns the ACK / NACK message provided from the next hop terminal.

  As described above, the base station can transmit the area information for transmitting the ACK / NACK message to the lower relay station using the map control message called the ACK Region Allocation information element defined in the IEEE 802.16 standard. Here, the ID of the lower relay station and the uplink ACK transmission area information are displayed in the map control message in units of OFDM subchannels and OFDM symbols.

  If the scheme shown in FIG. 12 is used, the base station includes the end point or start point information of each of the multiple ACK channels in the map control message. On the other hand, when the scheme shown in FIG. 13 is used, the base station does not include additional information in the map control message, and according to the order promised between the base station and the relay station, Transmission is possible.

  As described above, the relay station is provided from the lower node by transmitting the multiple control channel for the control message for data retransmission from the upper node of the wireless communication system using the multi-hop relay scheme to the lower node. There is an advantage that a control message for an automatic retransmission request (Automatic Retransmission reQuest) and a control message for an automatic retransmission request transmitted by itself can be simultaneously transmitted to an upper node.

On the other hand, although the specific embodiments have been described in the detailed description of the present invention, it goes without saying that various modifications can be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should not be determined by being limited to the embodiments described, but should be determined by the scope described in the appended claims and equivalents thereof.

Claims (49)

A method for operating a relay station in a wireless communication system using a relay method,
A process for checking whether an error has occurred in data received from an upper node; and
If no error occurs in the data, the process of transmitting the data to a lower node;
If at least two messages are received in response to receipt of data from at least one lower node, transmitting the at least two messages to the upper node at the same time;
A method comprising the steps of:   The method according to claim 1, wherein the upper node is a base station or an upper relay station.   The method of claim 1, wherein the lower node is a lower relay station or a terminal.   The at least two messages include at least one of at least one ACK message for data transmitted to at least one lower node and at least one NACK message for data transmitted to the at least one lower node. The method of claim 1, wherein: The process of transmitting the at least two messages to an upper node includes:
Confirming control channel information for transmitting the at least two messages provided from the upper node;
The method according to claim 1, further comprising: transmitting the at least two messages to the upper node at the same time using an area confirmed from the control channel information. The process of transmitting the at least two messages to an upper node includes:
Confirming a region allocated to each unique identifier of a lower node through the control channel information;
Assigning the at least two messages according to the reception of data provided from each lower node to the area allocated for each lower node, and transmitting the same to the upper node at the same time. The method of claim 5. The process of transmitting the at least two messages to an upper node includes:
Confirming the data of the at least two messages upon receipt of the data;
Confirming the order of data received scheduling information from the upper node;
A step of sequentially assigning the at least two messages according to the data reception of the corresponding data to the region confirmed via the control channel information according to the order of the data received the scheduling information;
The method according to claim 5, further comprising: transmitting the sequentially assigned messages to the upper node.   The method of claim 7, wherein the scheduling information is map (MAP) information. According to the time of transmission of the at least two messages, further comprising the step of confirming a message inventory for the at least two messages in response to receipt of data to be transmitted to the upper node,
The sequentially assigning step includes a step of sequentially assigning at least two messages included in the message list among the at least two messages provided from the lower nodes to the area confirmed through the control channel information. The method according to claim 7.   The method according to claim 9, wherein the message list is provided from the upper node through broadcast information or a separate control channel. Further comprising generating at least two messages for data received from the upper node after confirming whether the error has occurred;
The method of claim 1, wherein the step of transmitting the message to the upper node includes a step of transmitting the generated message and at least two messages received from the lower node to the upper node at the same time. Method. The process of transmitting the at least two messages to an upper node includes:
Confirming control channel information for transmitting the at least two messages provided from the upper node;
Using the area where the control channel information is confirmed, and transmitting the generated message and at least two messages provided from the lower node to the upper node at the same time. The method of claim 11. The process of transmitting the at least two messages to an upper node includes:
Confirming data indicating whether or not an error has occurred in the generated message and at least two messages provided from the lower node; and
Confirming the order of data received scheduling information from the upper node;
Sequentially assigning the at least two messages according to the receipt of data to the area confirmed via the control channel information according to the order of the data received the scheduling information;
The method according to claim 12, comprising: transmitting the sequentially assigned messages to the upper node.   The method of claim 13, wherein the scheduling information is map (MAP) information. A method for operating a relay station in a wireless communication system using a relay method,
A process for checking whether or not an error has occurred in data received from a lower node; and
When no error occurs in the data, a process of transmitting the data to an upper node;
Transmitting at least two messages to an upper node at the same time when at least two messages are received from at least one lower node in response to receipt of data from a second lower node. Feature method.   The method of claim 15, wherein the lower node is a lower relay station or a terminal.   The method according to claim 15, wherein the upper node is a base station or an upper relay station.   The method of claim 15, wherein the at least two messages in response to receipt of the data include at least one of at least one ACK message and at least one NACK message. The process of transmitting the at least two messages to an upper node includes:
Confirming control channel information for transmitting the at least two messages provided from the upper node;
The method of claim 15, further comprising: transmitting the at least two messages to the upper node at the same time using an area confirmed from the control channel information. The process of transmitting the at least two messages to an upper node includes:
Confirming an area allocated for each unique identifier of each lower node through the control channel information;
Allocating the at least two messages according to receipt of the data provided from each lower node to an area allocated for each lower node, and transmitting the at least two messages to the upper node at the same time. 20. A method according to claim 19, wherein: The process of transmitting the at least two messages to an upper node includes:
Confirming data indicating the occurrence of an error in the at least two messages;
Confirming the order of data received scheduling information from the upper node;
A process of sequentially assigning a message indicating whether or not an error has occurred in the corresponding data according to the order of the data received in the scheduling information in the area confirmed through the control channel information;
20. The method of claim 19, comprising: transmitting the sequentially assigned messages to the upper node.   The method of claim 21, wherein the scheduling information is map (MAP) information. Further comprising a step of confirming a message inventory of a message indicating the presence or absence of at least two errors transmitted to the upper node according to a message transmission time point;
The sequentially assigning step includes a step of sequentially assigning a message included in the message list to an area confirmed through the control channel information among at least two messages provided from the lower node. The method of claim 21.   The method of claim 23, wherein the message list is provided from the upper node through broadcast information or a separate control channel. After confirming the occurrence of the error, further comprising generating a message indicating the presence or absence of an error for the data received from the lower node,
16. The step of transmitting the at least two messages to an upper node includes transmitting the generated message and at least two messages received from the lower node to the upper node at the same time. The method described in 1. The process of transmitting the at least two messages to an upper node includes:
Confirming control channel information for transmitting the at least two messages provided from the upper node;
And transmitting the generated message and at least two messages provided from the lower node to the upper node at the same time using an area in which the control channel information is confirmed. Item 26. The method according to Item 25. The process of transmitting the at least two messages to an upper node includes:
Confirming data indicating whether or not an error has occurred in the generated message and at least two messages provided from the lower node; and
Confirming the order of data received scheduling information from the upper node;
Sequentially assigning the at least two messages according to the data reception of the corresponding data according to the order of the data received the scheduling information to the region confirmed via the control channel information;
27. The method of claim 26, further comprising: transmitting the sequentially assigned messages to the upper node.   The method of claim 27, wherein the scheduling information is map (MAP) information. An operation method of an upper node in a wireless communication system using a relay method,
Allocating a control channel for providing at least one lower node error occurrence presence / absence message from a lower relay station;
Transmitting the control channel allocation information to the lower relay station;
A method comprising the steps of:   The method according to claim 29, wherein the upper node is a base station or an upper relay station.   The method according to claim 29, wherein the lower node is a lower relay station or a terminal. The process of assigning the control channel comprises:
Confirming a unique identifier of at least one subordinate node to be provided with the error occurrence presence / absence message;
30. The method of claim 29, further comprising: allocating a control channel for an error occurrence presence / absence message for each unique identifier. The process of assigning the control channel comprises:
Determining a subordinate node to be provided with the error occurrence presence / absence message;
Transmitting the information of the lower node to the lower relay station;
30. The method according to claim 29, further comprising: allocating a control channel for providing an error occurrence presence / absence message of the lower node from the lower relay station. The process of assigning the control channel comprises:
The method of claim 33, further comprising determining start point information and end point information of an area for receiving an error occurrence presence / absence message of the lower node from the lower relay station. A relay station device of a wireless communication system using a relay method,
A receiving unit that receives data in response to data received from the upper node and data received from the lower node; and
An inspection unit for inspecting an error in data received from the upper node;
When there is no error in the data, the transmitting unit transmits to the lower node, and when at least two messages are received from the at least one lower node upon receipt of the data, the transmitting unit transmits the message to the upper node at the same time point; ,
A device comprising:   36. The apparatus of claim 35, wherein the upper node is a base station or an upper relay station.   36. The apparatus of claim 35, wherein the lower node is a lower relay station or a terminal.   36. The apparatus according to claim 35, wherein the transmission unit transmits the data provided from the upper node to the lower node when no error occurs.   36. The apparatus of claim 35, wherein the reception unit confirms control channel information for transmitting the message using a signal provided from the higher order node.   The transmitting unit sequentially assigns the at least two messages provided from the lower node to the region confirmed via the control channel information according to the order of data received scheduling information from the upper node, 40. The apparatus of claim 39, wherein the apparatus transmits to a node. A message generation unit for generating a data error occurrence presence / absence message confirmed by the inspection unit;
The apparatus according to claim 35, wherein the transmission unit transmits the generated message and at least two messages provided from the lower node to an upper node at the same time. A relay station device of a wireless communication system using a relay method,
A receiving unit for receiving a message in response to data received from the first lower node and data from the second lower node;
An inspection unit for inspecting an error in the received data;
A transmitter that transmits the error-free data and transmits the message to the upper node at the same time when at least two messages are received in response to receipt of the data from the second lower node;
A device comprising:   The apparatus according to claim 42, wherein the upper node is a base station or an upper relay station.   44. The apparatus of claim 43, wherein the lower node is a lower relay station or a terminal.   The apparatus according to claim 43, wherein the transmission unit transmits the data provided from the first lower node to an upper node when no error occurs in the data.   44. The apparatus according to claim 43, wherein the reception unit confirms control channel information for transmitting the message from a signal provided from the upper node.   The transmission unit is provided in the region confirmed via the control channel information according to the order of data received scheduling information from the upper node, and is provided from the second lower node according to the reception of the data. The apparatus according to claim 46, wherein one message is assigned in sequence, and the at least two messages are transmitted to the upper node. A message generator for generating an error occurrence presence / absence message of the data confirmed by the inspection unit;
The apparatus according to claim 43, wherein the transmission unit transmits the generated message and at least two messages provided from the lower node to an upper node at the same time. A method for operating a relay station in a wireless communication system using a relay method,
Receiving at least two messages from one or more subordinate nodes upon receipt of data from the second subordinate node;
Sending the message to an upper node at the same time;
A method comprising the steps of:

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