On the Asymptotic Bit Error Probability of M-QAM for MIMO Y Channels

A theoretical analysis of bit error rate (BER) expression of adaptive M-ary quadrature amplitude modulation (M-QAM) for multiple-input multiple-output (MIMO) Y channels, where three users exchange independent messages with each other via a relay within two time slots, is proposed. Performance evaluation shows that the analytical BER closely matches the simulated one, particularly at high signal-to-noise ratios (SNRs).