An irregular repeat accumulate coded adaptive amplify-and-forward scheme based on the EESM model

Cooperative communication is a bright technology to acquire diversity gain in wireless terminals by sharing their antennas. With the fixed amplify-and-forward (AF) mode, relay node always helps to relay the data of the source node with unchanged transmission power. Judging from the power efficiency, it is obviously not optimal, particularly when channel states are quite good. An adaptive AF mode is provided in this paper based on the minus Exponential Effective-Signal to interference and noise ratio (SINR) Mapping (EESM) model, to the user cooperation system with the forward error correcting scheme of irregular repeat and accumulate (IRA) codes. The EESM model forecasts the optimal relay power of SN. The reliability requirement is guaranteed by IRA codes, and the battery power is saved to transmit new data. Both simulation results and theoretical analysis show that the power efficiency of user cooperation system is significantly improved the adaptive AF mode.