Receiver Design for SIMO-OFDM Systems with Insufficient Cyclic Prefix

We investigate orthogonal frequency-division multiplexing (OFDM) systems that operate with limited or insufficient cyclic prefix (CP). Using a shorter CP can enable a significant reduction in bandwidth usage or enable range extension for OFDM networks. The cost is increased inter-symbol interference (ISI) and inter-carrier interference (ICI). Here, the effect of ICI and ISI on the received signal is analyzed. We then propose a two-stage detector for single input multiple output (SIMO) systems with two receive antennas. Taking advantage of the spatial diversity, the first detection stage uses a low complexity zero-forcing (ZF) or minimum mean square error (MMSE) method to estimate the transmitted data for aiding the second stage trellis based detector. The proposed schemes provide satisfactory performance for delay spreads up to 3.5 times the CP.