Phase-Shifter-Aided Spatial Multiplexing: Transmitting More Streams With Less RF Chains

Multiple-input multiple-output (MIMO) technology has been extensively investigated for achieving spatial multiplexing and diversity gains. However, the introduction of multiple radio-frequency (RF) chains at the MIMO transmitter becomes a bottleneck due to high implementation cost. To address this challenge, we propose a novel phase-shifter-aided spatial multiplexing (PSSM) scheme, which utilizes phase shifters for multi-stream transmissions with reduced RF chains. Furthermore, the multiplexing-diversity tradeoff is studied through theoretical analysis for such system to illustrate its advantage, meanwhile the performance bound in terms of bit-error rate (BER) is quantified. Finally, simulation results demonstrate the superiority of the proposed PSSM scheme over its conventional counterparts in terms of BER, especially under high transmission rate requirements.