MIMO SPACE-TIME BLOCK CODES AND CHANNEL ESTIMATION FOR MOBILE WIMAX DL-PUSC

High-speed mobility, high data throughput, and flexibly scalable architecture are some of the key advantages of mobile WiMAX (Worldwide interoperability for Microwave Access) or wireless metropolitan area network, which is now being considered as the initiation of the next generation wireless network. Recently, multiple-input multiple-output (MIMO) techniques, especially the mature Space-Time Block Codes (STBC) scheme, have attracted lots of interest for increasing both transmission capacity and quality. Although MIMO for OFDM systems was intensively studied in literatures, published works usually demonstrate the system performance with a perfect knowledge of channel while channel estimation plays a very important role in determining the real performance. This paper aims to apply MIMO-STBC with a novel channel estimation method to the Downlink-Partial Usage of Subchannels (DL-PUSC) mode of the mobile WiMAX system to study the system performance more practically. Performance analysis is carried out by simulating the system in many mobile channel models recommended by ITU and COST259. The results show that MIMO-STBC in 802.16e DL-PUSC provides a great improvement over the single-input single-output (SISO) approach and the new channel estimation method enhances the performance farther. Up to 15 dB gain with STBC and 1-3 dB more with the new channel estimation scheme are achieved.