Uplink Channel Estimation in WiMAX

Abstract

WiMAX is an emerging and powerful technology in broadband wireless communications in that it can provide high-speed broadband voice and data ser- vices over distances much greater than Wi-Fi. However, like in any wireless communication system, signal distortion due to channel fading, noise, and Doppler can limit the overall transmission data rate and coverage. To minimize this effect, the receiver must perform channel estimation to remove the effects of the channel. To aid the channel estimation process, known pilot subcarriers are embedded into each OFDM symbol. In this thesis, we will develop and evaluate pilot-assisted channel estimation algorithms for 3 WiMAX modes and features: PUSC (Partial Usage of Subcarriers), AMC (Adaptive Modulation and Coding), and Channel Sounding. Our results show that channel delay spread and signal-to-noise ratio influence the performance of each algorithm and that knowledge of these properties can enhance the system's overall performance.