Energy-Efficient Receiver-End Phase Synchronization for Collaborative Transmission Over Nakagami-m Fading Channels
Smriti Sachdev, Swades K. De · IEEE Transactions on Green Communications and Networking · 2025
In collaborative wireless transmission from N independent nodes, up to N2 power gain with respect to a single-node transmission is achievable at the receiver. However, achieving synchronization among the participating nodes can be energy-intensive due to high communication and computation overheads. To achieve distributed beamforming (DBF)-like N2 power gains in resource-constrained nodes, we propose blind receiver-end phase synchronization methods with minimal overheads. The reduced processing is achieved in two steps. First, we transform the N-dimensional hypercube search space for phase corrections of N nodes into N one-dimensional searches. Next, we exploit the unique phase distribution of the Nakagami-m fading channel between the transmitters and the receiver to reduce the search space to a finite set of values. Two complementary methods, namely, reduced search space (RSS) method and extended RSS (extRSS) method are proposed that offer energy-efficient solutions in diverse channel fading conditions. For tractable performance analysis of the proposed methods, two approximations are derived for the Nakagami-m phase distribution, respectively for m>1 and m≤1, and closed-form expressions are obtained for the average power gain in the two cases. The numerical and simulation results demonstrate that extRSS achieves fading agnostic near-perfect average power gain for 12 search points per transmitter, while RSS achieves near-perfect average power gain for 4 search points per transmitter, under strong LOS conditions. Both proposed methods are shown to have significantly reduced computational and energy requirements compared to the closest competitive approaches in the literature.