Improvement in Error Performance by Cooperation

For mobile users without antenna arrays, transmission diversity can be achieved with cooperative transmissions, or by multi-branch system which uses the relays reached by the transmitter. When there is only one relay that can be reached by the transmitter, the transmission diversity can be obtained by a multi-hop system, then we emulate the (2 transmit antennas, 2 receive antennas) cooperative diversity scheme. This approach successfully deals with the problem of just one receiving antenna in a handset. Simulation results indicate an improvement in error performance over the simple (2,1) Alamouti (coded) or relaying scheme.