Turbo-space time block coded and turbo-vertical bell laboratories layered space time coded wireless communication: Which one is better to use and under what circumstances?

Abstract

In this research, performance of Turbo-Space Time Block Coded and Turbo-Vertical Bell Laboratories Layered Space Time coded Multiple Input Multiple Output Wireless Communication System is compared and investigated to find which one is better under which circumstances. The Turbo Encoder accepts binary bits as input and generates turbo encoded bits as output which is sent to 64 QAM modulator. These 64 QAM Modulated symbols are further mapped using Space Time Block Code and Vertical Bell Laboratories Layered Space Time code for Turbo-Space Time Block Coded system and Turbo-Vertical Bell Laboratories Layered Space Time coded system respectively and then divided into several streams based on number of transmit antennas before transmission. It is found that there is 3 to 22 dB coding gain at 10-5 for using Turbo-STBC instead of using Turbo-VBLAST for 2 or 3 or 4 transmit antennas and 2 or 3 or 4 or 5 or 6 receive antennas. On the other hand, at low SNR STBC shows 1-2 b/s/Hz improvement in capacity compare to VBLAST but capacity declines significantly at high SNR for using STBC. It is also observed that VBLAST improves the capacity around 5 to 15 b/s/Hz at high SNR.