PROJECT TITLE :

Estimation and Mitigation of Channel Non-Reciprocity in Massive MIMO - 2018

ABSTRACT:

Time-division duplex (TDD)-based mostly massive MIMO systems depend on the reciprocity of the wireless propagation channels when calculating the downlink precoders based mostly on uplink pilots. But, the effective uplink and downlink channels incorporating the analog radio front-ends of the base station (BS) and user equipments (UEs) exhibit non-reciprocity due to non-identical behavior of the individual transmit and receive chains. When the downlink precoder isn't conscious of such channel non-reciprocity (NRC), system performance can be significantly degraded due to the NRC-induced interference terms. In this Project, we have a tendency to contemplate a general TDD-primarily based large MIMO system where frequency-response mismatches at both the BS and UEs, further as the mutual coupling mismatches at the BS massive-antenna system all coexist and induce channel NRC. Based mostly on the NRC-impaired signal models, we have a tendency to 1st propose a novel iterative estimation method for acquiring both the BS and UE facet NRC matrices and then additionally propose an efficient NRC-aware downlink precoder style which utilizes the obtained estimates. Furthermore, an efficient pilot signaling theme between the BS and UEs is introduced so as to facilitate executing the proposed estimation technique and the NRC-aware precoding technique in practical systems. Comprehensive numerical results indicate substantially improved spectral efficiency performance when the proposed NRC estimation and NRC-aware precoding ways are adopted, compared to the present state-of-the-art strategies.