Effect of phase noise and imperfect channel estimation on coded OFDM transmit diversity with application to IEEE 802.16e

In this paper, we investigate the effects of RF impairments and imperfect channel estimation (ICE) on the performance of quadrature amplitude modulation (QAM) for orthogonal frequency division multiplexing (OFDM) systems employing transmit diversity with two transmit antennas and one receive antenna in a Rayleigh fading environment. We derive the bit error rate (BER) expressions of space-time block codes (STBC)-OFDM system using the Alamouti code. Although the analysis is presented for 16-QAM, it can be easily extended to higher order square QAM constellations. Simulation results are also presented to illustrate the extent of the effects on system performance degradation, with emphasis given to the IEEE 802.1e standard.