AGC and Quantization Effects in a Zero-Forcing MIMO Wireless System

This paper considers automatic gain control (AGC) and quantization for multiple-input multiple-output (MIMO) wireless systems. We examine the effect of clipping and quantization on capacity and bit error rate (BER). We find that even quite low resolution quantizers can perform close to the capacity of ideal unquantized systems. Results are presented for BPSK and M-ary QAM, and for 2times2, 3times3, and 4times4 MIMO configurations. We find that in each case less than 6 quantizer bits are required to achieve 98% of unquantized capacity for SNRs above 15 dB