Achieving Channel Reciprocity in Multi-Carrier System: SRS Carrier-Based Switching

In the context of approaching next generation cellular network where increasing antennas are installed, link quality largely depends on channel information acquired at transceivers. Sounding Reference Signal (SRS) carrier-based Switching, an emerging technique developed starting from 3GPP Release-14 standards, enables SRS transmitted on non-SRS carriers to provide base station reciprocity-aided channel information; therefore it accomplishes better precoding selection for beamforming and becomes a critical role in multi-carrier aggregation system. In this article, we look into SRS Switching and present a comprehensive analysis for this technique. A standard-compatible and high-efficiency SRS Switching algorithm is proposed, and then implemented into a system-level simulator to evaluate the network performance in terms of downlink throughput. We extract the design principle from analyzing its own characteristics. Also, the rationales behind why the technique works are identified from the numerical results. More than an implementation of standardized technique, out algorithm can serve as precious basis for its practical realization and further evolution of standards. Compared with conventional SRS cases, the remarkable performance enhancement has revealed significant superiority of our proposal which suggests a bright prospect of this technique in next generation mobile wireless network.