Performance analysis of iterative interference cancellation receiver based on MMSE detection

Abstract

Multiple-input multiple-output system is considered as the technique to provide the spectral efficiency and diversity of wireless communication systems. Among several MIMO techniques, bit interleaved coded modulation (BICM) is a coding technique which is designed for fast fading channels. It was shown in [1] that with maximum likelihood (ML) detector, MIMO-BICM systems outperform space-time trellis codes in fast fading conditions. The disadvantage of the ML receiver is the high computational complexity for computing the log-likelihood ratio (LLR). However, recent advances in signal processing techniques have led to the development of the list sphere decoder (LSD), which generates the list around the received vector. If the numbers in a list are large, then the search remains exponential in size, whereas if the number is too small, then the performance of MIMO-BICM is deteriorated severely. A significant complexity reduction can be obtained by employing linear detectors such as zero-forcing (ZF) and minimum mean square error (MMSE) detectors in place of ML detector. Unfortunately, a coded MIMO-BICM system with a ZF detector or a MMSE detector has the smaller diversity order than that of system with a ML detector. In this thesis, we will introduce the iterative receiver structures that consist of two components. The first thing is the detector, which is aimed to generate LLR``s of coded bits. The second component is the channel decoder. Roughly, an iterative receiver can improve the performance significantly by exchanging the soft outputs of one component to the other. The iterative receivers with linear detectors are mainly studied in this thesis. A comprehensive analysis of MIMO-BICM with ZF detector is provided in [2]. However, the receiver structure of [2] is not iterative. It is well known that MMSE detector outperforms ZF detector. Besides finding the upper bound on bit error probability, we analyze the capacity of MIMO-BICM with MMSE detector to show the...