Linear two dimensional pilot assisted channel estimation for OFDM systems

Orthogonal frequency division multiplexing (OFDM) is considered an effective technique in high speed digital transmission due to its spectral efficiency, its robustness in different multipath propagation environments and its ability to combat intersymbol interference (ISI). Coherent modulation combined with OFDM gives an optimum performance but needs a powerful channel estimator. We present a channel estimation method based on pilot symbols inserted both in time and frequency domains, and a linear interpolation algorithm. This linear interpolation algorithm has the advantage of minimising the system complexity and processing delay while giving a good approximation to the real mobile channel. The performance of the linear pilot aided estimation algorithm is compared to coherent modulation with perfect channel estimation as well as to differential modulation