Performance Analysis of Adaptive Antennas in the Uplinks of WIMAX (802.16e) Systems

This paper provides a closed form expression of the bit error probability for coherent and noncoherent detection of PSK, FSK and QAM signals using adaptive arrays with optimum combining in the presence of multiple interferers and thermal noise. The obtained results are applied to characterize the performance of adaptive array systems in mobile communications operating over Rayleigh/Ricean fading channels. The use of adaptive arrays in 802.16e improves the system performance, where beamforming is implemented in the direction of the desired user. The conventional beamforming, Capon and MUSIC algorithm is used to compute the direction of arrival for the OFDM uplink. 802.16e provides specifications for non-LOS, mobile wireless communications in the 2-6 GHz range. The simulations help selecting the correct values of OFDM symbol time, T_s, in different channel conditions.