Deliberately Designed Asynchronous Transmission Scheme for MIMO Systems

Oversampling at each receive antenna is equivalent to having multiple polyphase components with correlated channel gains and colored noise, provided that the signal bandwidth is higher than Nyquist bandwidth. To exploit the potential of these polyphase components in the MIMO systems, this letter advocates the approach of using deliberately designed asynchronous transmission instead of the synchronous transmission usually employed. Simulations show that the asynchronous transmission can easily outperform its synchronous counterparts. Moreover, it opens up the possibility of using fewer antennas at the receiver, particularly in a subscriber unit where there are severe constraints on size, weight, and power consumption.