Performance Analysis of ST , SF and STF in MIMO - OFDM Technique

In this paper with the advent of next generation (4G) broadband wireless communications, the combination of multiple-input multiple-output (MIMO) wireless technology with orthogonal frequency division multiplexing (OFDM) has been recognized as one of the most promising techniques to support high data rate and high performance. In particular, coding over the space, time, and frequency domains provided by MIMO-OFDM will enable a much more reliable and robust transmission over the harsh wireless environment. In this article we provide an overview of space-time (ST) coding, space-frequency (SF) coding, and space-time-frequency (STF) coding for MIMOOFDM systems. Performance results show that STF coding can achieve the maximum diversity gain in an end toend MIMO-OFDM system over broadband wireless channels. Furthermore, for orthogonal frequency division multiple accesses (OFDMA), we propose a multiuser SF coding scheme that can achieve the maximum diversity for each user while minimizing the interference introduced from all the other users.