Energy-Efficient Distributed Detection Through Feedback-Assisted Ordered Transmissions in the Presence of Fading and Quantization

We propose a novel energy-efficient feedback-enhanced successively reordered transmissions scheme (FE-SRTS) that combines distributed multiple access-based ordered channel access, feedback from the fusion node (FN), and quantized payloads. In FE-SRTS, the sensor nodes sequentially transmit their log-likelihood ratios (LLRs) to the FN until the latter decides. The order in which the nodes transmit is updated based on feedback from the FN and is implemented in a distributed manner using the timer scheme. We derive novel decision rules that enable FE-SRTS to achieve the detection error probability of the optimal rule in which the FN knows the LLRs of all nodes, but with a substantially lower average number of transmissions than conventional ordered and unordered schemes. We also account for retransmissions and power control due to fading, quantized payloads, and feedback. We analyze the average number of sensor transmissions and the total energy consumed by FE-SRTS. The analysis leads to insightful asymptotic results that establish the efficacy of FE-SRTS for Gaussian statistics. Our simulations, based on the Zigbee standard, show that the total energy consumed by FE-SRTS is markedly lower than by conventional schemes.