Performance Analysis Of STBC-OFDM System In The Impulsive Noise

With the integration of Internet and multimedia services in next generation wireless communications, the demand for wide-band high data rate communication services is growing. In the future broadband wireless communications, there will be two severe challenges to be faced, which are frequency selective fading channels and bandwidth efficiency. Owing to these two challenges, MIMO and OFDM are imposed on more attention. Being one of the core MIMO techniques, the space-time code technique takes a very important status in the MIMO-OFDM system.Multiple-input-multiple-output (MIMO), employing multiple antennas on both transmitter and receiver, can improve the system capacity and performance without expanding the bandwidth or increasing transmit power. Space-time code (STC) is the coding scheme based on transmit diversity that can improve MIMO performance. Space-time block code (STBC), according to orthogonal design at the transmitter, can apply the maximum-likelihood decoding algorithm at the receiver. Because of its simple coding and decoding architectures and good performance, it has been used as the standard of W-CDMA and CDMA2000. Orthogonal frequency division multiplexing (OFDM), transforming high rate data transmission into lower rate transmission with multiple orthogonal sub-carriers, can eliminate frequency selective fading.In the paper, firstly the multiple-input-multiple-output technology and the multiple carriers multiplexing technology are discussed. Also the characters of wireless channels are introduced. After that, the STBC is introduced and the performance of STBC in frequency flat channels is simulated. On the other hand, the theory of OFDM and the key technologies are described. Simulatings above are based on frequency flat channels, while this paper makes more emphasis on the performance of STBC-OFDM in frequency selective fading channels. Moreover, the COST 207 fading channels are selected as the model of the frequency selective fading channels. The performance results of STBC-OFDM in different COST 207 fading channels are given, which contain typical Rural Area (RA), Typical Urban (TU), Bad Urban (BU) and Hilly Terrain (HT).It is noted that aforementioned researches are performed in Gaussian white noise. However, the non-Gaussian noise in the realistic communication systems is prevalent. Therefore, the performance results of STBC-OFDM with the non-Gaussian noise.are also researched. Then the performance of STBC-OFDM with the non-Gaussian noise in the COST 207 fading channels is explored, and Middleton Class A is selected as the model of the non-Gaussian noise. At last, the performance results are given.