Space Time block Codes :An Orthogonal Structured Codes for Wireless Fading Environment.

ISpace time block codes are the orthogonal codes design with an objective to reduce the interference in the fading environment.In mimo systems where there are multiple antenna at the transmitter side there will be a high probability of interference amongst the signal when all the users transmit the data simultaneously thus space time block codes provide an effective solution in such scenario with its orthogonal structure design which minimises the interference and thus make the receiver to easily demodulate the incoming arriving signal at the respective receiving antenna and thus detection of signal at the receiver will become quite simple with much reduced complexity.In this research paper various equalization techniques at transmitter and receiver are presented which aims to reduce the ISI ,other source nterferences and thus reduce BER(bit error rate)which is a measure of performance of various communicating system The organization of paper is as follows section1introduces the reader to space time block codes.section 2 give an overview of channel models .section3 provides space time block coding with different schemes,section 4 represents system models.section 5 depicts different diversity techniques to combat fading.section 6 provide an insight of equlization techniques at transmitter .section 7 famialarize with equalization techniques at the receiver transmitter. Simulation results shows ber analysis of defferent techniques and confirm sphere decoder is an optimum decoder with much reduced complexity.