Performance analysis of multi‐pair two‐way amplify‐and‐forward relaying with imperfect CSI over Ricean fading channels
Xiaoli Sun, Kui Xu, Youyun Xu · IET Communications · 2017
This study investigates the spectral efficiency (SE) and energy efficiency (EE) of a multipair two‐way massive multiple‐input multiple‐output amplify‐and‐forward relaying system over Ricean fading channels. Both maximum‐ratio combining/maximum ratio transmission and zero‐forcing transmission/zero‐forcing reception beamforming matrices are considered at the relay with imperfect channel state information (CSI). The asymptotic signal‐to‐interference‐plus‐noise ratio expressions (in the number of relay antennas M ) are derived. Moreover, four power scaling schemes are proposed and the asymptotic SE and EE based on the proposed power scaling schemes are obtained analytically. Theoretical analyses and simulation results show that with imperfect CSI when M tends to infinity, the transmit power should be scaled down to different proportions for the Ricean channel with and without line‐of‐sight components to maintain a desirable rate. However, when M tends to infinity, SE is independent of the Ricean K ‐factor with perfect CSI.