Two-Step Signal Detection for MIMO-OFDM Systems without Cyclic Prefix

In this paper, a MIMO-OFDM system without cyclic prefix (CP) is considered and a two-step signal detection algorithm is proposed. The algorithm is based on some structural properties derived from shifting the received OFDM symbols. The first step cancels inter-carrier interference (ICI) and inter-symbol interference (ISI) with an equalizer designed using second-order statistics of the shifted received OFDM symbols. The second step detects the signals from the equalizer output in which the signals are still corrupted with multi- antenna interference (MAI). In the proposed algorithm, precise knowledge of the channel length is unnecessary and only one pilot OFDM symbol is utilized to estimate the required channel state information, assuming the number of transmit antennas is smaller than the number of subcarriers in one OFDM symbol. Simulation results show that the proposed algorithm achieves comparable performance to algorithms for MIMO-OFDM system with cyclic prefix and it is robust against channel length overestimation.