Performance Analysis of Discrete-Rate Adaptive Modulation with Space-Time Coding in Multiple Antennas System

Based on the channel sate information feedback, the performance of multi-antenna systems with adaptive modulation and space-time coding in Rayleigh fading channels is presented in this paper. The fading gain value is partitioned into a number of regions by which the modulation is adapted in terms of the region the fading gain falls in. The fading gain region boundaries for attaining maximum spectrum efficiency under a target bit error rate (BER) and fixed power constraint are attained. Based on these results, we derive the theoretical calculation formulae for the system spectrum efficiency and average BER in detail. As a result, the closed-form expressions for the spectrum efficiency and average BER are obtained, respectively. These formulae will be more accuracy than the existing formulae. Simulation results show that the theoretical SE and BER are in good agreement with the corresponding simulated values.