Equalization Techniques for Time Varying Channels in MIMO based Wireless Communication

Abstract

In mobile integrated service digital network, high bit-rate data transmission is essential for many services such as video, multimedia etc. When data is transmitted at high bit-rate, wireless channels exhibit delay dispersion because of multipath components (MPC). Different propagation times from transmitter (Tx) to receiver (Rx) in MIMO systems produces different MPCs. This in turn leads to Inter Symbol Interference (ISI), which can greatly disturb the transmission of digital signals. If delay spread is smaller than the symbol duration, it can lead to considerable Bit Error Rate (BER) degradation. Equalization defines any signal processing technique used at re c e ive r to make the signal less susceptible to delay spread. Equalizers require an estimate of channel impulse or frequency response to mitigate the ISI. In this paper the performance of equalization techniques are compared by considering 2 transmit and 2 receive antennas (resulting 2x2 MIMO Channel). Assume that channel is flat fading Rayleigh multipath- channel and modulation is BPSK.