Study of Transmission Characteristics of MIMO System for Different Modulation Techniques
Narendra M. R.

Narendra M R, Department of Electronics and Communication, Canara Engineering College Mangalore (Karnataka), India.
Manuscript received on 11 June 2013 | Revised Manuscript received on 17 June 2013 | Manuscript Published on 30 June 2013 | PP: 151-154 | Volume-3 Issue-1, June 2013 | Retrieval Number: A0931063113/13©BEIESP
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Abstract: The performance of 2X2 Multiple Input multiple Output (MIMO) antenna systems has been analyzed by determining the transmit diversity using Alamouti Space Time Coding (STBC) techniques. For the BPSK and QPSK modulation technique transmission characteristics are determined. Adaptive White Gaussian Noise (AWGN) has been used presuming flat fading Rayleigh channel. On receiver side, linear equalization techniques such as Zero Forcing (ZF) and Maximum Likelihood Detector (MLD) were employed for computing BER. It is found that for 5 dB Eb/No, the BER values of BPSK using ZF Equalizer 0.0687, BPSK using MLD Equalizer 0.0151, QPSK using ZF Equalizer 0.0070, QPSK using MLD Equalizer 1 is obtained. But BER value for BPSK Modulation with 2X2 Alamouti STBC and the BER value for QPSK Modulation with same 2X2 Alamouti STBC are obtained respectively as 0.0038 and 0.0034. The results indicate that the STBC multiplexing schemes show an overall improvement of ~67.95 dB between BPSK and QPSK modulation for the same 5 dB Eb/No value. The STBC multiplexing for digital transmission shows significant improvement in BER performance with higher levels of digital modulation. MATLAB tool is used for simulation and results are discussed in the paper.
Keywords: Multiple Input Multiple Output (MIMO), Space Time Block Code (STBC) Phase Shift Keying (PSK).

Scope of the Article: Wireless Multimedia Systems