Impact of Transmission Synchronization Error and Cooperative Reception Techniques on the Performance of Cooperative MIMO Systems

Wireless sensor networks where neighbor nodes can cooperate both at transmission and reception by using the cooperative multi-input multi-output (MIMO) technique are considered. Space-time diversity gain can be exploited to reduce the transmission energy consumption which is very important for average and long range transmission in wireless sensor network (WSN). However, differing from classical MIMO systems, cooperative systems suffer from the lack of synchronization between distributed nodes and the additive noise in the cooperative reception. At the cooperative transmission side, we investigate the effect of transmission synchronization error which generates inter-symbol interference (ISI), decreases the desired signal amplitude and makes the channel state information (CSI) more difficult to be estimated by the receiver. At the cooperative reception side, two strategies of wireless transmission techniques which are energy efficient and have good performance are also presented. The simulation of a cooperative MIMO system using Alamouti and Tarokh space-time block codes (STBC) over Rayleigh fading channels presents a performance degradation in the presence of transmission synchronization error and additional noise of cooperative reception techniques. For a small synchronization error range at cooperative transmission and a reasonable amplification factor in reception, the degradation is negligible and the cooperative MIMO performance is rather good.