Performance of Adaptive Modulation with Space-Time Block Coding and Imperfect Channel State Information over Rayleigh Fading Channel

Abstract

The performance analysis of adaptive MQAM/MPSK with space-time block coding (STBC) and imperfect channel state information (CSI) over Rayleigh fading channels is presented. The fading gain value is partitioned into a number of regions by which the modulation is adapted according to the region the fading gain falls in. Under a target bit error rate (BER) and fixed power constraint, the fading gain switching thresholds and the probability density function of fading gain under imperfect CSI are respectively derived. Based on the above results, the closed-form expression for the SE is obtained. A tightly closed-form approximation of average BER is derived by means of the approximation of complementary error function. Computer simulations verify the effectiveness of the derived theoretical SE and BER expressions.