Integrated MAP detector with statistical channel information for vector OFDM systems
Vector OFDM (V-OFDM) for single transmit antenna is a general transmission scheme that can bridge the gap between OFDM and SC-FDE (Single-Carrier Frequency Domain Equalization). Because of the attractive properties it has, such as controllable PAPR, capability to exploit the signal space diversity, etc., V-OFDM has drawn more and more attention recently. At the receiver end, the conventional coherent receiver usually assumes separated detector and channel estimator, which limits the system performance. The integrated MAP (IMAP) receiver, proposed by Luo and Huang for V-BLAST and OFDM, combines the detector and channel estimator and is shown to have better performance than the separated ones. In this paper, we exploit the principal of I MAP, and develop the receiving algorithm for V-OFDM. By utilizing the special structure of the V-OFDM signal, we propose some methods to simplify the IMAP receiver. In the simulations, we show that the developed IMAP receiver performs much better than the receiver composed of separated conventional MAP (CMAP) detector and MMSE channel estimator, where both of them assume the same knowledge of the channel correlation statistical information and noise variance. Further, it is shown that when the sub-block size of V-OFDM is 4 and using 2 sub-blocks as pilots, the performance gap between the IMAP receiver, which has only statistical channel information, and the CMAP receiver with perfect instantaneous channel state information is less than 0.5dB.