Simulation Annalysis of Spatial Diversity Along with Channel Codes in Multipath Environment

Abstract

Wireless systems are rapidly developing to provide high speed voice, text and multimedia messaging services which were traditionally offered by wire line networks. To support these services, channels with large capacities are required. Theoretic investigations in the past few years have shown that very high capacities can be obtained by employing multiple antenna elements at both the transmitter and the receiver end of a wireless system.

In MIMO system of wireless communications, Space time block coding (STBC) is one of the attractive technique for high bit-rate and high capacity transmission. Methods for providing transmit diversity in communication over fading channels also been concerned. The advantage of space-time codes lies in the fact that diversity advantage is obtained by shifting the complexity of adding additional antennas to the transmitter while allowing the complexity of receiver to be reasonably low.

Recently, low-density parity-check (LDPC) codes have attracted much attention as the good error correcting codes achieving the near Shannon limit performance like turbo codes. In this thesis the concatenation scheme of STBC codes and LDPC (STBC-LDPC) is proposed and it has been shown that the STBC-LDPC can achieve the good error rate performance and coding gain. Referring to it as the STBC-LDPC, we evaluate the bit error rate (BER) of the STBC-LDPC with multiple transmit antennas in different fading environments. We see that as we increase the increase the number of antennas the performance improves as well due to the increasing diversity gain.