Large-Scale Fading Coefficient Estimation in Wireless Massive MIMO Systems

摘要

Efficient algorithms for estimating LSFCs with no aid of SSFCs by taking advantage of the channel hardening effect and large spatial samples available to a massive MIMO base station (BS) are proposed. The LSFC estimates are of low computational complexity and require relatively small training overhead. In the uplink direction, mobile stations (MSs) transmit orthogonal uplink pilots for the serving BS to estimate LSFCs. In the downlink direction, the BS transmits either pilot signal or data signal intended to the MSs that have already established time and frequency synchronization. The proposed uplink and downlink LSFC estimators are unbiased and asymptotically optimal as the number of BS antennas tends to infinity.

主权项

1. A method comprising:
receiving radio signals transmitted from K mobile stations (MSs) by a base station (BS) in a massive multiple input and multiple output (MIMO) uplink channel, wherein the BS has M antennas, and wherein M>>K; vectorizing received radio signals denoted as a matrix YεM×T, wherein the transmitted radio signals are orthogonal pilot signals denoted as a matrix PεK×T transmitted from the K MSs, and wherein T≧K is the pilot signal length; and deriving an estimator of large-scale fading coefficients (LSFCs) of the uplink channel with unknown small-scale fading coefficients (SSFCs) of the uplink channel.