Ordered Successive Interference Cancellation and Sphere Detection Technique for MIMO

Abstract

The advent of multiple inputs, multiple output (MIMO) system has had a major influence on how the current capacity limits of a single antenna system could be increased without the need of overwhelming computational complexity. MIMO systems may be broadly classified into two categories: those designed to increase the transmission rate through spatial multiplexing and those designed to increase reliability using diversity techniques. Most of the current researches are concerned with the spatial multiplexing design scheme as it offers very high increase in data rate. The detection scheme for spatial multiplexing techniques includes linear receivers like Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) and non-linear receivers like Successive Interference Cancellation (SIC), Ordered Successive Interference Cancellation (OSIC) and Sphere Detection (SD). This thesis reviews briefly the MIMO system and the spatial multiplexing technique and compares various detection schemes used in MIMO system. Based on the BER analysis, the performance of various detections schemes in Rayleigh Channel is conducted. Different aspects have been considered in the evaluation of performance namely signal to noise ratio (SNR), modulation order and the number of transmitter and receiver antennas. The Maximum Likelihood (ML) detection method has shown optimum detection for MIMO system however the complexity involved is very high which leads to use of low complexity detection schemes. The performance of linear detection scheme like ZF, MMSE and non-linear schemes like SIC and the OSIC are first reviewed and then a quite new SD algorithm is analyzed where the SD provides near ML solution with much less computational complexity. The obtained results are inter-compared and discussed from different performance aspects.