KR101052273B1 - Method for receiving data in wireless communication system and wireless communication system using same - Google Patents

Abstract

Disclosed are a method for requesting retransmission of data in a wireless communication system and a wireless communication system using the same. According to the data retransmission request method, the method includes receiving data from a source node, broadcasting a retransmission request message for data, and re-receiving data through a specific relay node. As a result, a high diversity order can be obtained, and the data transmission rate can be improved by minimizing the signal delay between the transmitting end and the receiving end.

Relay method, ARQ

Description

Method for receiving data in wireless communication system and wireless communication system using same {DATA RECEIVING METHOD IN WIRELESS COMMUNICATION SYSTEM AND WIRELESS COMMUNICATION SYSTEM USING THE SAME}

The present invention relates to a method for receiving data in a wireless communication system and a wireless communication system using the same, and more particularly, to an automatic retransmission request (hereinafter referred to as 'ARQ') in a wireless communication system using a relay method. And a wireless communication system using the same.

 In a typical wireless communication system, data is transmitted and received through communication between a base station and a terminal. However, when the location of the base station is fixed, the flexibility of environmental changes between the base station and the terminal is low, and thus, it is difficult to provide an efficient communication service in a wireless environment in which the traffic distribution or the call demand change is severe.

In order to solve this problem, a multi-hop relay data transmission scheme using a relay station is used. The wireless communication system using the multi-hop relay method can quickly reconfigure the network in response to changes in the communication environment, and can operate the entire wireless network more efficiently to provide superior channel conditions.

Meanwhile, in wireless data communication, an error may occur in specific data according to a channel state of a radio resource interval. The ARQ scheme is to control such an error, and the ARQ scheme is a method of requesting retransmission to the transmitting end or the relay station for data lost at the receiving end.

However, when retransmission is requested to the relay station, the diversity is lowered if all the relay stations retransmit the lost data. Therefore, by receiving data using only the optimal relay station among all the relay stations, the necessity of achieving a high diversity order is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for requesting retransmission of data in a wireless communication system capable of obtaining a high diversity order and obtaining higher frequency efficiency and using the same. The present invention provides a wireless communication system.

According to an aspect of the present invention, there is provided a method of requesting data retransmission in a wireless communication system, the method comprising: receiving broadcast data from a source node; If there is an error in the data, broadcasting a retransmission request message for the data; And re-receiving the data through a specific relay node among at least one relay node receiving the retransmission request message.

Here, the re-receiving step may receive the cooperation information broadcasted from the specific relay node based on the retransmission request message, and re-receive the data included in the cooperation information.

The cooperation information may include information indicating that the specific relay node is an optimal relay node.

In addition, the cooperation information may include information for stopping the operation of the relay node receiving the broadcasted cooperation information.

The specific relay node may be a relay node when the timer is 0 when the timer is operated by measuring a channel coefficient based on the received retransmission request message.

The data receiving step may receive an error detection code together with the data from the source node, and the retransmission request step may determine whether an error exists in the data using the error detection code.

In the retransmission request step, if there is no error in the data, ACK information may be transmitted to the source node to request transmission of the next data.

The data retransmission request method according to the present embodiment may further include generating final data by combining the received data with the re-received data.

The retransmission request step may request retransmission of the data by broadcasting NACK information.

On the other hand, a method for retransmitting data in a wireless communication system according to an embodiment of the present invention for achieving the above object comprises the steps of: receiving broadcast data from a source node; Receiving a request for retransmission from a destination node; And retransmitting the data to the destination node when the timer is 0 when there is no error in the received data and the timer is operated by measuring a channel coefficient through the retransmission request.

In addition, a wireless communication system according to an embodiment of the present invention for achieving the above object, the transmitting station for broadcasting data; At least one relay station receiving the broadcast data; And a receiving station that broadcasts a retransmission request message for the data if there is an error in the broadcasted data and re-receives the data through a specific relay station of the at least one relay station that has received the retransmission request message; It includes.

Here, the receiving station may receive the cooperation information broadcasted from the specific relay station on the basis of the retransmission request message, and receive the data included in the cooperation information again.

The cooperation information may be information indicating that the specific relay station is an optimal relay station.

The cooperation information may include information for stopping the operation of the relay station receiving the broadcasted cooperation information.

The specific relay station may be a relay station when the timer is 0 when the timer is operated by measuring a channel coefficient based on the received retransmission request message.

The receiving station may receive an error detection code together with the data from the transmitting station, and determine whether an error exists in the data using the error detection code.

In addition, if there is no error in the data, the receiving station may transmit ACK information to the transmitting station and request transmission of the next data.

The receiving station may combine the received data with the re-received data to generate final data.

In addition, the receiving station may request retransmission of the data by broadcasting NACK information.

As a result, a high diversity order can be obtained, and the data transmission rate can be improved by minimizing the signal delay between the transmitting end and the receiving end.

Hereinafter, with reference to the drawings will be described the present invention in more detail. 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. As shown, the wireless communication system includes a node S (hereinafter, collectively referred to as a 'source node'), a node D (hereinafter, collectively referred to as a 'destination node') and a plurality of nodes R (hereinafter, referred to as a 'relay node'). The wireless communication system according to the present embodiment performs an automatic retransmission request using a relay node.

An automatic retransmission request (hereinafter, collectively referred to as 'ARQ') is a request for retransmission of data lost at a destination node to a source node or a relay node. Therefore, the automatic retransmission request using the relay node according to the present embodiment means to request retransmission to the relay node for the data lost at the destination node.

As shown, the source node broadcasts the data to send data to the destination node, and the data broadcast at the source node is received by the relay nodes and the destination nodes. On the other hand, the source node broadcasts an error detection code together with the data. Accordingly, the relay node or the destination node that has received the error detection code can know whether an error exists in the received data by using the error detection code. Examples of such error detection include error detection using a cyclic redundancy check (CRC) code.

Thereafter, the destination node determines whether an error exists in the data broadcast from the source node, and performs different operations according to the determination result.

2A and 2B are diagrams provided to explain the operation when no error exists in the data broadcast in the source node.

The destination node having received the data and the error detection code determines whether an error exists in the received data using the error detection code. If it is determined that no error exists in the received data, as shown in FIG. 2A, the destination node transmits ACK information to the source node.

Thereafter, the source node and the destination node perform direct transmission without using a relay node. As shown in FIG. 2B, the destination node receives data directly from the source node through direct transmission.

3A to 3C are diagrams provided to explain an operation when an error exists in data broadcast at a source node.

The destination node having received the data and the error detection code determines whether an error exists in the received data using the error detection code. If it is determined that an error exists in the received data, as shown in FIG. 3A, the destination node broadcasts NACK information.

The relay nodes receiving the NACK information measure a channel coefficient using the received NACK information, and operate a timer using the measured channel coefficient. The relay node whose timer is zero first broadcasts the cooperative information to indicate that it is the optimal relay node, as shown in FIG. 3B.

On the other hand, such cooperative information includes data broadcast from the source node and information for stopping the operation of another relay node. Therefore, the destination node that has received the cooperation information broadcasted at the optimal relay node can receive the data broadcasted at the source node by receiving the received cooperation information. In addition, the other relay node receiving the cooperative information broadcast from the optimal relay node stops operations such as data transmission to the destination node by receiving the received cooperative information, so that data is redundantly transmitted to the destination node. Can be prevented.

Thereafter, the source node and the destination node perform cooperative transmission using an optimal relay node. As illustrated in FIG. 3C, the destination node uses cooperative transmission, and transmits data transmitted from the source node through the optimal relay node. Will receive.

Meanwhile, in order to increase the reliability of the received data, the destination node may combine the data received from the source node with the data received via the relay node to generate final data.

4 is a flowchart provided to explain the data retransmission method according to the present invention in more detail.

First, the transmitting station broadcasts data for transmission to the receiving station (S410). The receiving station that has received the broadcasted data from the transmitting station determines whether an error exists in the received data (S420).

If it is determined that an error exists in the received data (S420-Y), the receiving station communicates with the transmitting station through cooperative transmission, and if it is determined that no error exists in the received data (S420-N), the receiving station Communicates with the transmitting station via direct transmission.

Cooperative transmission is a method of transmitting data using a relay station. For cooperative transmission, the receiving station broadcasts NACK information (S430). The RSs receiving the NACK information measure the channel coefficients and operate the timer using the measured channel coefficients (S440).

Thereafter, each RS determines whether its timer is 0 (S450), and if it is determined that its timer is 0 (S450-Y), it generates and broadcasts cooperative information (S460). The cooperative information is information indicating that it is an optimal relay station. The cooperative information includes data broadcast from the transmitting station, and information for stopping the operation of the relay station receiving the broadcasted cooperative information.

Accordingly, the other relay station receiving the cooperative information is stopped, and the receiving station receiving the cooperative information receives data by communicating with the optimal relay station (S470).

Each relay station determines whether its own timer is 0 (S450), and if it is determined that its timer is not 0 (S450-N), it determines whether cooperation information is received from another relay station (S455). .

If the cooperative information is received from another relay station (S455-Y), the relay station which transmitted the cooperative information becomes an optimal relay station. In addition, since the cooperative information includes information for stopping the operation of the relay station which has received the cooperative information, the relay station which is not the optimal relay station stops the operation (S465).

On the other hand, direct transmission is a method of transmitting data without using a relay station. For direct transmission, the receiving station transmits ACK information to the transmitting station (S480). The transmitting station receiving the ACK information no longer broadcasts the data, but transmits the data directly to the receiving station. Accordingly, the receiving station communicates directly with the transmitting station (S490).

While the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention;

2A and 2B are diagrams provided for explaining an operation when no error exists in data broadcast at a source node;

3A to 3C are diagrams provided to explain an operation when an error exists in data broadcast at a source node, and

4 is a flowchart provided to explain the data retransmission method according to the present invention in more detail.

Claims (19)

In the method for requesting data retransmission in a wireless communication system, Receiving broadcasted data from a source node; If there is an error in the data, broadcasting a retransmission request message for the data; And And re-receiving the data through a specific relay node among at least one relay node receiving the retransmission request message. The re-receipt step, Receive the cooperation information broadcasted from the specific relay node based on the retransmission request message, and re-receive the data included in the cooperation information; The cooperation information, Retransmission request method comprising information indicating that the specific relay node is an optimal relay node. delete delete The method of claim 1, The cooperation information, Retransmission request method comprising the information to stop the operation of the relay node receiving the broadcasted cooperation information. The method of claim 1, The specific relay node, And a relay node when the timer is 0 when the timer is operated by measuring a channel coefficient based on the received retransmission request message. The method of claim 1, In the data receiving step, an error detection code is received together with the data from the source node, In the retransmission request step, the error detection code is used to determine whether an error exists in the data. The method of claim 1, The retransmission request step, If the error does not exist in the data, retransmission request method characterized in that by transmitting the ACK information to the source node, the transmission of the next data. The method of claim 1, And combining the received data with the re-received data to generate final data. The method of claim 1, The retransmission request step, Retransmission request method characterized in that to request the retransmission of the data by broadcasting NACK information. In a method for retransmitting data in a wireless communication system, Receiving broadcasted data from a source node; Receiving a request for retransmission from a destination node; And Retransmitting the data to the destination node when the received data has no error and the timer is 0 when the timer is operated by measuring a channel coefficient through the retransmission request. A transmitting station that broadcasts data; At least one relay station receiving the broadcast data; And A receiving station broadcasting a retransmission request message for the data and receiving the data through a specific relay station among the at least one relay station receiving the retransmission request message when an error exists in the broadcast data; Include, The receiving station, Receiving the cooperation information broadcasted from the specific relay station based on the retransmission request message, and receiving the data included in the cooperation information again; The cooperation information, And a information indicating that the specific relay station is an optimal relay station. delete delete The method of claim 11, The cooperation information, And information for stopping the operation of the relay station that has received the broadcasted cooperation information. The method of claim 11, The specific relay station, And a relay station when the timer is 0 when the timer is operated by measuring a channel coefficient based on the received retransmission request message. The method of claim 11, And the receiving station receives an error detection code together with the data from the transmitting station, and determines whether an error exists in the data using the error detection code. The method of claim 11, The receiving station, And if there is no error in the data, transmitting ACK information to the transmitting station to request transmission of the next data. The method of claim 11, And the receiving station combines the received data with the re-received data to generate final data. The method of claim 11, The receiving station, Requesting retransmission of the data by broadcasting NACK information.

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