Optimal Frame Splitting for Downlink MIMO Channels With Distributed Antenna Arrays

A frame-splitting (FS) scheme is proposed to exploit spatial diversity in the downlink wireless transmission from a base station (BS) to a mobile station (MS) that has multiple receive antennas. The BS has multiple geographically distributed arrays, each consisting of multiple transmit antennas. The scenario comprises a number of downlink multiple-input-multiple-output (MIMO) channels from different BS arrays to an MS with mutually independent Rayleigh-fading processes. A data frame from the BS for the MS is split into portions, which are consecutively transmitted from multiple BS arrays. For the FS transmission scheme, the distribution of information capacity is formulated on the basis of the FS fractional lengths of the portions. Analytical evaluation of the outage probability reveals the optimal setting of FS fractional lengths for the maximum diversity advantage based on knowledge of the long-term average signal-to-noise ratios (SNRs) of the downlink MIMO channels.