Performance evaluation of MIMO-WCDMA cellular networks in multiuser frequency selective fading environments

This paper investigates the performance of different transmission strategies for multiple input multiple output (MIMO) networks with the wideband code division multiple access (WCDMA) air interface as the physical layer protocol. Performance is evaluated statistically with extended Monte Carlo (MC) simulations in terms of achievable bit-error (BER) rate in frequency selective fading cellular environments. As results indicate, for a MIMO configuration with Mt antennas at the base station (BS), Mr antennas per mobile station (MS) and L resolvable multipath components, the transmission strategy based on signal to noise ratio (SNR) enhancement is the optimum transmit solution for Mt ≤ Mr. However, the pre-RAKE maximal ratio combining transmission strategy outerperforms the SNR enhancement strategy with post-RAKE processing for Mt > Mr, high number of resolvable multipath components and channel estimation error up to 40%. Moreover, a transmission scheme based on the maximization of the ratio of the desired MS’s signal to the total amount of interference that causes to the network is proposed, and is shown that outerperforms the conventional transmission schemes for high data rate services. For symmetric MIMO configurations (Mt = Mr) and two resolvable multipath components, this strategy provides 30% BER gain compared to the maximization of SNR strategy. This gain can be further improved by 25% with a proposed adjacent sector cooperation algorithm. Copyright © 2011 John Wiley & Sons, Ltd.