Cooperative MIMO system for WiMAX technology

In this paper, we propose a cooperative Multiple-Input Multiple Output (MIMO) system where the cooperation uses amplify-and-forward (AF) relaying strategy and the MIMO is based on Vertical Bell-Labs Layered Space Time (V-BLAST) architecture. The idea is to simultaneously exploit the advantages offered by cooperative diversity and MIMO and the proposed system is intended for use in Worldwide Interoperability for Microwave Access (WiMAX) technology. Complexity of the cooperative MIMO (Co-MIMO) is also analyzed considering Maximum Ratio Combining (MRC) and Equal Gain Combining (EGC) schemes; Zero Forcing (ZF), Minimum Mean Square error (MMSE) and Maximum Likelihood (ML) detections; and V-BLAST transmission technique at transmitting node. Simulation results show that, at comparable complexity, Co-MIMO achieves significantly better symbol error rate (SER) performance than the conventional cooperative diversity or MIMO system only. As an example, at SER of 10^-3, Co-MIMO system using MMSE detection has 10 dB signal-to-noise ratio (SNR) gain over systems that employ cooperative diversity or MIMO only.