MIMO OFDM System with Virtual Receive Antennas

In our earlier work, a novel concept of virtual receive antennas (VRA) was proposed and is a viable solution for single carrier spatial multiplexing system with less number of physical receive antennas. In this paper, we investigate the VRA system in spatially multiplexed orthogonal frequency-division multiplexing (OFDM) system, which is a promising scheme for next generation of downlink communication. To create VRA in OFDM, various fractionally spaced timing offset is imposed to each transmit substream and oversampling at the receiver filter output. To explore the potential of the VRA-OFDM system, this paper analyzes its system capacity and error rate performance. Results show that the VRA-OFDM system can achieve higher ergodic capacity and outage rate, and lower outage probability than conventional MISO-OFDM system. Due to the created virtual antennas, ordered successive interference cancellation (OSIC) can be used in the VRA-OFDM system, which favours the use of VRA in downlink communication due to lower complexity. Meanwhile, if maximum likelihood (ML) detection is used, the VRA-OFDM system shows better BER performance than the conventional overloaded MISO-OFDM ML receiver.