Closed-Form BER Analysis of Alamouti-MRC Systems with ICSI in Ricean Fading Channels

In this letter, we derive an exact closed-form expression for the bit error rate (BER) of an M-ary quadrature amplitude modulation (QAM) multiple-input multiple-output (MIMO) 2×N_R system that employs Alamouti´s space time block code (STBC) transmission and maximal ratio combining (MRC) reception, when imperfect channel state information (ICSI) is considered in a Ricean fading channel. An approximate yet accurate expression for the BER is also provided when a strong line of sight (LOS) component is considered. It is observed that the loss of orthogonality of Alamouti´s code due to ICSI leads to a non-negligible noise enhancement.