Patent ID: 7586846

Claim:
A method for relaying a signal in a source node of a communication system, the method comprising the steps of: calculating a data rate of an Adaptive Modulation and Coding (AMC) mode, which is used to maximize a data rate on each of a first link between the source node and a destination node, a second link between the source node and a relay node, and a third link between the relay node and the destination node; calculating a first data rate for the case where a multi-hop mode is used for signal transmission between the source node and the destination node; calculating a first optimal data rate for the case where transmission modes available for signal transmission between the source node and the destination node include a direct mode and the multi-hop mode; selecting an AMC mode to be used for the first link and determining a second data rate for the first link when the selected AMC mode is used; calculating an available signal-to-noise ratio (SNR) needed to decode a superposed message after a basic message is decoded, when a signal transmitted from the source node to the destination node includes the basic message and the superposed message; determining a third data rate at which the superposed message is transmitted with reliability; calculating a second optimal data rate for the case where a transmission mode available for signal transmission between the source node and the destination node is the superposition mode; determining whether the second optimal data rate exceeds the first optimal data rate; and determining to use the superposition mode for signal transmission from the source node to the destination node, if the second optimal data rate exceeds the first optimal data rate.