Optimal Power Allocation for Space Shift Keying Modulation in a Distributed Antenna System

In a distributed antenna system (DAS), remote antenna units (RAU) cooperate to form a distributed SSK transmitter (DAS-SSK), where each RAU is equipped with multiple antennas but a single radio-frequency (RF) chain. The fading channel of each RAU distributes with a different variance due to the different propagation distance and shadowing fading. In this letter, a tight upper bound on the symbol error rate (SER) of the DAS-SSK system is derived based on the union bound analysis. A convex-optimization-based optimal power allocation scheme among RAUs is proposed, which shows a significant performance improvement.