OFDM techniques for MIMO-OFDM system: A review

Abstract

MIMO-OFDM technology converts frequency selective MIMO channel into number of parallel flat fading MIMO channel.It fundamentally simplifies the baseband receiver processing by eliminating the need of complex MIMO equalizer. In this paper every one of the strategies that provide increased BER performance for OFDM has been discussed. Linear Constellation Precoding (LCP) with subcarrier grouping technique has been introduced to overcome the multipath fading that result from conventional OFDM. Later on Nonlinear Constellation Precoding (NCP) without subcarrier grouping is introduced to replace the LCP technique. NCP strategy is adaptable to diversity channels and diversity order irrespective of their number which is not in case of LCP scheme. At end Nonlinear Constellation Precoding (NCP) with subcarrier grouping is introduced. As a conclusion, in future if the same procedures are implemented in the OFDM part of MIMO-OFDM system it will provide improved BER than conventional MIMO-OFDM system.