Design and Simulation of Transmitter Diversity Techniques for OFDM Systems

• Main Authors: Meng-Lin Ku, 古孟霖
• Other Authors: Chia-Chi Huang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/57458208297517330033

碩士 === 國立交通大學 === 電信工程系 === 91 === The thesis introduces two transmitter diversity techniques for Orthogonal Frequency Division Multiplexing (OFDM) systems. One is a space-time block coded OFDM system. The other one is a differential space-time block coded OFDM system. The space-time block coded OFDM system uses a space-time block coding scheme at the transmitter and combine signals optimally at the receiver. Diversity gain can be achieved by using two spatially separated transmitter antennas to transmit signals with only a small increase in the complexity of the receiver. The system requires the knowledge of the channel at the receiver for the purpose of the signal detection. Complementary code based pilot signals are transmitted in the time domain for the purpose of the channel estimation. The pilot signals are transmitted in a special order to ensure that they have good auto-correlation and cross-correlation properties in the code matching process at the receiver. The differential space-time coded OFDM system uses a differential space-time block coding scheme at the transmitter. The system can obtain a great benefit in the diversity gain without transmitting pilot signals. Computer simulations are used to evaluate the performance of both systems.