Cooperative relay transmission method for a wireless communication system

A cooperative relay transmission method for use in a base station of a wireless communication system configured by a plurality of terminals and the base station for providing a network access service to the plurality of terminals in which one of the plurality of terminals is selected as a source terminal and at least one of the other terminals is used as a relay node for relaying communication between the base station and the source terminal, comprising the steps of:

• initializing parameters for relay communication;
• broadcasting a relay communication request message comprising the parameters;
• setting a possible relay terminal for performing the relay communication between the base station and the source terminal among the plurality of terminals in response to the relay communication request message;
• receiving uplink signals from the source terminal and relay terminals;
• and
• combining and decoding the uplink signals received from the source terminal and relay terminals,
• wherein the parameters include a maximum number of relay terminals (Nmax), a minimum number of relay terminals (Nmin), and a required channel quality (Q) and an allowable relay distance (D) for setting a relay terminal, and wherein the setting the relay terminal comprises the steps of:
• measuring a distance (Dpresent) from the base station in a terminal receiving the relay communication request message;
• determining whether a condition of D>Dpresent is satisfied;
• and
• activating a relay function if the condition of D>Dpresent is satisfied.

A cooperative relay transmission method for use in a base station of a wireless communication system configured by a plurality of terminals and the base station for providing a network access service to the plurality of terminals in which one of the plurality of terminals is selected as a source terminal and at least one of the other terminals is used as a relay node for relaying communication between the base station and the source terminal, comprising:

• initializing parameters for relay communication;
• broadcasting a relay communication request message comprising the parameters;
• setting a possible relay terminal for performing the relay communication between the base station and the source terminal among the plurality of terminals in response to the relay communication request message;
• receiving uplink signals from the source terminal and relay terminals;
• and
• combining and decoding the uplink signals received from the source terminal and relay terminals, wherein receiving the uplink signals comprises:
• decoding the uplink signals received from the source terminal and the possible relay terminal;
• temporarily storing the uplink signal when the decoding is successful in the possible relay terminal;
• broadcasting a re-transmission request message when the decoding fails in the base station;
• and
• setting the possible relay terminal to the relay terminal only if the possible relay terminal has a value of more than a threshold value defined in a relay parameter upon receiving the retransmission request message, compensating for signal phase variation due to a channel between the relay terminal and the base station, and transmitting a temporarily stored uplink message to the base station.