Exact BER Analysis of Hierarchical M-QAM in Spatially Correlated MIMO Nakagami Fading Channels

We derive closed-form expressions for the exact average bit error rate (BER) of hierarchical square M-ary quadrature amplitude modulations (M-QAMs), when these modulation schemes are used along with orthogonal space-time block coding (STBC) over correlated multiple-input multiple-output (MIMO) Nakagami-m fading channels with arbitrary fading parameters. The derived formulae can be used to assess the effects of spatial correlation on the BER performance of hierarchical M-Q AM.