Interference mitigation using channel shortening pre-filter for SIMO-OFDM systems

In this work, we explore the channel shortening pre-filter (CSP) for single-input multi-output orthogonal frequency division multiplexing (SIMO-OFDM) system in the presence of co-channel interference (CCI), inter-block-interference (IBI) and inter-carrier-interference (ICI). Here, IBI and ICI are caused by the fact that the delay spreads of the multi-path impulse response are longer than the cyclic prefix duration for either the desired signal or the interfering signal, or both. We analytically derive the minimum order of the CSP which cancels a single strong CCI, IBI and ICI using three or more receive antennas. Simulation results show that the uncoded bit-error-rate (BER) curve does not floor at higher value of E_b/N₀ for this minimum choice of CSP order. Interference suppression with only two receive antennas are simulated to show that multiuser diversity gain obtained due to narrow-band resource allocation is also important to mitigate CCI, IBI and ICI. However, the receiver with CSP can provide nearly 2-orders of magnitude lower BER when compared to a receiver without CSP.