Nguyen Tuan Khanh creator Ahmed, Kazi Mohiuddin Chairperson Erke, Tapio J. Examination Committee Fernando, W.A.C. Examination Committee Ho Chi Minh City Post and Telecommunications Scholarship donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2003 continuing eng 49 leaves Antenna diversity is an effective technique to increase the stabilization in wireless communication system without bandwidth expansion. Space-Time Block Codes (STBC), using Orthogonal structure, is also a diversity technique to improve the performance of the system. STBC can achieve the full diversity gain with very simple decoding but can not get perfect performance for coding gain. Trellis-Coded Modulation (TCM) is a kind of channel coding with improving the coding gain. Therefore, Concatenation of STBC and TCM is a combined channel coding to achieve both diversity and coding gain advantages. In this research study, we evaluate the performance of STBC with different numbers of antennas at the transmitter and at the receiver in both basic STBC and concatenated STBC with TCM. We also consider the STBC with different kinds of modulation and TCM over frequency-flat fading channel and frequency -selective fading channel. Simulation results show that the more antennas at transmitter or at receiver get better the performance. The performance of STBC with using matrix G3(3Tx,1Rx) can improve about 5.5 dB comparing with G2(2Tx,1Rx) and the better performance of G4(4Tx,1Rx) is about 2.5 db comparing with G3(3Tx,1Rx). With the same diversity order of 4, the basic STBC using G2 with 2Tx and 2Rx antennas has better performance about 3 dB comparing with G4 using 4 Tx and 1 Rx. The concatenated STBC with TCM can achieve a gain of 11.2 dB more than the basic STBC at a BER level of 10-5 over frequency-flat fading channel. A research study submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Advanced Technologies Research report (M.Sc.) - Asian Institute of Technology, 2003 Space and time Digital communications Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B08428 http://203.159.5.9/ait-thesis/detail.php?q=B08428 030507 20260818084705.0