Performance Comparison of Turbo Coded Single Input Multiple Output System Using Selective Combining, Equal Gain Combining and Maximal Ratio Combining

Abstract

This paper compares the performance of a Turbo Coded Single Input Multiple Output (SIMO) system with uncoded SIMO system using selective combing, equal gain combing and maximal ratio combining. Turbo Coded system uses Turbo encoder to encode the input information before modulation, whereas uncoded system modulates input information without using turbo encoder. QPSK or 16 QAM or 64 QAM modulator modulates the information and transmit it from single transmit antenna. Receiving antennas of receiver receive transmitted information and combine using selective combing or equal gain combing or maximal ratio combining. It is observed that the turbo coded system with 2, 4, 6 and 8 receive antennas using selective combining provide 35, 28, 24 and 24 dB coding gain respectively, turbo coded system with 2, 4, 6 and 8 receive antennas using equal gain combining provide 34, 22, 20 and 19 dB coding gain respectively and turbo coded system with 2, 4, 6 and 8 receive antennas using maximal ratio combining provide 27, 17, 15 and 13 dB coding gain respectively compared to uncoded system at a BER 10 -6 . It is also observed that turbo coded system using maximal ratio combining provides 20 to 26 dB coding gain at a BER of 10 -6 compared to turbo coded system using equal gain combining. And turbo coded system using maximal ratio combining provides 23 to 26 dB coding gain at a BER of 10 -6 compared to turbo coded system using selective combining.