A Multiuser CQI Prediction Scheme with Channel Estimation Error in the Massive MIMO Networks

Massive multiple-input multiple-output (MIMO) wireless communication refers to the idea equipping transmitters with a very large number of antennas, and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency by using relatively simple (linear) processing. In a multi-user MIMO (MU-MIMO) spatial multiplexing scheme, multiple users are scheduled in the same resource block (RB). In 3GPP Long Term Evolution (LTE) systems, single user MIMO (SU-MIMO) rank one precoding based channel quality indicator (CQI) reporting mechanism is reused for MU-MIMO. This is optimum for MU-MIMO if single user is served. This paper is to get an insight of the multi user CQI prediction. A method to estimate the multi user CQI from the reported rank 1 single user CQI is proposed for the space division multiple access (SDMA) mode and zero-forcing (ZF) precoding. Simulation results illustrate that the derived asymptotic value of the MU-MIMO CQI is very close to the real value of that.