Tradeoff between BER and Bandwidth Efficiency in MIMO Systems with ZF Equalization
Shûichi Ohno, Kok Ann Donny Teo · 2006
Multiple-input multiple-output (MIMO) wireless systems offer multiplexing gain and diversity gain. While it is known that the diversity order of MIMO transmissions with Nttransmit and Nrreceive antennas over i.i.d. Rayleigh fading channels is Nr- Nt+ 1 at high signal-to-noise ratio (SNR), the same conclusion cannot in general be drawn for bit-error rate (BER) gain for all SNR and other channels. We show a BER performance ordering for different transmit antenna sizes in MIMO wireless systems with practical zero-forcing (ZF) equalization, which hold for all SNR. We prove that when the number of receive antennas is fixed, the average BER improves with a decrease in the number of transmit antennas, which shows the tradeoff between BER and bandwidth efficiency in MIMO with ZF equalization