Analysis of MIMO OFDM Based WiMAX System with LDPC

Driven by multimedia based applications, the future wireless systems require high data rate capable technologies. WiMAX has attracted immense interest globally for next generation wireless communication. The requirement of a spectrally efficient modulation technique and power efficient forward error correction scheme are key factors for these technologies. Wireless link quality is determined by transmission rate, range and reliability. Multiple Input Multiple Output (MIMO), along with Orthogonal Frequency Divsion Multiplexing(OFDM) techniques improve these parameters and are also habituated in WiMAX. It uses smart antenna techniques which include spatial transmit diversity and spatial multiplexing (SM). Spatial transmit diversity is achieved by applying Alamouti´s Space Time coding. To achieve high capacity with minimum error rate Low-Density Parity-Check (LDPC) codes have recently drawn much attention and have superior interest because their error correction performance in wide applications. These codes are called Tanner graph which have short cycles that degrade the performance of LDPC decoders. The Quasi Cyclic (QC) LDPC as channel coding method is incorporated in the paper. STBC is used as a MIMO technique providing a strong diversity gain. Analysis of the performance of MIMO OFDM physical layer in WiMAX with the use of LDPC under different digital modulation techniques is presented in this paper.