Performance Analysis of Space Time Code

Space-time Coding is an advanced technology in the area of Wireless Communications. It employs multiple antennas at the transmitter and receiver to increase the capacity and the quality of the systems, by providing both diversity gain and/or coding gain.

Current research in the field of Space-time Coding focuses on the code construction and code design criteria. It can be shown that the more complex the Space-time Code is, the better performance the code can achieve. However, to increase the complexity of the codes, the performance simulation time tends to be very long. In order to counter such a problem and save on manpower at the same time, theoretical performance evaluation methods are strongly desired. This is the main objective of this thesis.

After substantial review of Space-time Coding literature, the performance of various codes has been evaluated theoretically. The performance of the codes is characterized by its Bit Error Probability (BEP) and Frame Error Probability (FEP). Both of them are evaluated based on the Pair-wise Error Probability (PEP) of the codes. In this thesis, the BEP and FEP are evaluated for the codes over Slow Fading Channels. Under Slow Fading Channels, the PEP is computed based on the Moment Generating Function introduced by Dr. Simon [2]. With PEPs, the number of error event paths, the number of bit errors for each error event path, and the BEPs of three types of Space-time Codes are evaluated. Another easier method to evaluate PEP is based on the Upper bound of PEPs introduced by Tarokh [1]. This method is much easier, however, it sacrifices accuracy in the lower range of the signal-to-noise ratio, especially for codes with a large number of receive antennas.