Energy-efficient transmission and bit allocation schemes in wireless sensor networks

Energy-efficient transmission and bit allocation schemes are investigated in multi-source single-sink Wireless Sensor Networks (WSNs). For transmission over Additive White Gaussian Noise (AWGN) channels with path loss, this work shows that the overall energy consumption can be minimised if each sensor transmits with the minimum power and cooperates with others in Time-Division Multiple Access (TDMA) mode. From the efficient correlated source coding perspective, the Slepian-Wolf coding theorem is applied. Jointly considering the two aspects, we propose a closed form bit allocation scheme to minimise the overall energy consumption. The underlying idea is to assign more bits to nodes with better channel conditions. Additionally, based on the definition of network lifetime as the time before the first sensor fails, we further maximise the network lifetime by developing a heuristic algorithm to balance energy consumption among sensors. The superiority of the proposed scheme is validated by both analytical and simulation results.