Performance analysis of π/4 DQPSK in IEEE 802.16e system under frequency selective fast fading environment

Channel estimation is of the prime importance in frequency selective fast fading environment while considering mobile WIMAX (IEEE 802.16e). Estimation algorithms help in improving BER performance in multipath fading and mobility scenario. These techniques are useful especially in coherent detection. But it increases the complexity of the system. Use of differential mapping scheme like 7r/4 DQPSK may be an alternative for this because of no requirement of phase error correction at receiver side. In this paper performance comparison has been made between system incorporating estimation (coherent detection) and not including estimation (differential). Convolution channel coding has been used for analysis. Simulation has been performed for mobile WiMAX (802.16e) under frequency selective fast fading scenario.