Performance Analysis of Overloaded Mimo-Ofdm Systems Using Iterative Joint Turbo Decoding

Abstract

The Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) employs
turbo codes as its Forward Error Correction (FEC) standard along with multiple input,
multiple output (MIMO) systems is used for achieving an excellent error correcting
capability and higher throughput. Even if turbo decoding scheme gives adequate
performance in ideal MIMO systems, but there is a significant performance degradation
in an overloaded MIMO system when the number of transmit antennas is larger than that
of receive antennas. In joint turbo decoding, controls of soft information be located
accompanied for every permutation of bits from all stream. A super trellis diagram is
obtained by combining the trellis diagram of each stream. Experimental results obtained
through the joint turbo decoding achieve better performance than the turbo decoding
scheme especially in the case of an overloaded MIMO systems. In this paper, BER and
throughput for joint turbo decoding scheme is analyzed with different channels (TU
channel, Rayleigh fading channel, Rician fading channel) and compared with viterbi
decoding. Based on this analysis, joint turbo decoding scheme of MIMO systems with
four transmit and two receive antenna of Rician fading channel achieved better
performance with BER of 10-3
and higher throughput.