Influence on OFDM Channel Estimation by Modulations of Pilot Symbol

A frequency-domain channel estimation (CE) scheme for orthogonal frequency division multiplexing (OFDM) channel estimation which is based on a linear transformation is developed. The transmitted signal can be recovered efficiently by a linear transformation of the received signal. Firstly, two results on the generalized rotation matrix are deduced. Then based on the modulations of pilot symbols BPSK or QPSK, we achieve two channel estimation algorithms respectively. Simulations are performed at the condition that the channel is assumed to be Rayleigh fading and flat within one frame. Simulation results show that the BER and PER performance can be improved obviously when in-phase channel and quadrature-phase channel of each sub-carrier are inserted in the pilot symbols.