Effect of oscillator phase noise on uplink performance of large MU-MIMO systems

The effect of oscillator phase noise on the sum rate performance of a frequency selective multi-user multiple-input multiple-output (MU-MIMO) uplink channel is studied under imperfect channel state information. A maximum ratio combining detection strategy is employed by the base station (BS) (having a large antenna array of M elements), and an analytical expression of a lower bound on the sum capacity of the system is derived. It is shown that an array power gain of O(√M) is achievable. It is also observed that phase noise effectively limits the fraction of the time used for information transmission and the number of users in the system. Finally it is concluded that, phase noise degrades the performance but does not eliminate the fundamental gains of a Large Scale Antenna System (LSAS), i.e., power efficiency and high sum rate performance with low complexity receiver processing.