Energy efficient transmission techniques for wireless sensor networks

Power against rate performance of a class of transmission techniques is studied in this paper. This study arises in the context of a wireless sensor network in which multiple nodes equipped with single or multiple antennas cooperatively send simultaneous and distinct signals to multiple receiving nodes, each equipped with a single receiving antenna. The criterion in deriving the techniques is to eliminate or minimise the mutual interference so as to maximise received signal-to-interference plus noise ratio. It is shown for low bit rates that time-shared transmission can achieve the performance of the optimal power shared technique operating in spatially uncoupled (ideal) channels. As the bit rate increases, time-shared transmission becomes suboptimal. In this study, best linear optimisation, dirty paper coding and zero forcing are promising techniques.