Dual stream low complexity BICM reception and MIMO broadcast strategy

Abstract

In this paper we consider channel coding for dual data streams with unequal error protection (UEP) for the objectives of low complexity receiver structures and prioritized handling of data in MIMO broadcast systems. We focus on high spectral efficiency bit interleaved coded modulation (BICM) MIMO OFDM system where two independently coded spatial streams of symbols are simultaneously transmitted by an antenna array using antenna cycling. In some sense, the receiver then views a multiple access channel (MAC) and consequently the reception is based on successive interference cancellation (SIC). The limited adaptability of the proposed system helps gear up to a higher data rate as channel conditions improve without any adjustment at the transmitter. This leads to devising a broadcast strategy incorporating different levels of service. Standard receiver solutions for such schemes employ sub-optimal linear minimum mean square error (MMSE) successive stripping decoders. We propose a novel low complexity near optimal demodulator based on match filter outputs for a dual stream system which exhibits better performance and lower complexity as that of MMSE based demodulator.