4 x 4 MIMO-WiMAX Systems

Abstract EN

In this paper different MIMO-OSBTC-OFDM systems have been proposed and evaluated.

The performance of MIMO system with Space Time Coding concatenated with a Convolutional code as a channel code has been studied.

Code matrices with two different code rates (R=1/2 and 3/4) have been used and compared.

According to the type of QAM modulation, Convolutional Code with code rates (1/2 and 2/3).The systems evaluated over Additive White Gaussian Noise (AWGN) and Rayleigh fading channel of two types Flat-Fading and Frequency-Selective Fading with different values of Doppler frequencies (5, 50, and 100) Hz.

The results shows that the code matrix with R= 1/2 gives a better results than the one with R= 3/4, because when R=3/4 three symbols are send during 4 time slots, but when R=1/2 just two symbols are send during four time slots.