Peak to average power ratio reduction in MIMO-OFDM systems by using LDPC Codes

Abstract

Multiple Input and Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems is the potential candidate for fourth generation (4G) mobile radio communication systems. The MIMO-OFDM systems are further providing increasing in the data throughput without increasing in the bandwidth and also provide a reduction in the fading. However, the main drawback of OFDM systems is the high peak to average power ratio (PAPR).This disadvantage can be reduced by a number of methods but most of them cause an increase in the bit error rate (BER), data rate loss and an increase in the computational complexity. Thus, the coding methods have been used to reduce the PAPR. LDPC codes were one of the first codes to allow data transmission rates close to the theoretical maximum, the Shannon limit. These codes show improved performance over an AWGN channel. In this thesis, the PAPR reduction performance with LDPC codes mainly investigated and compare the result with two different PAPR reduction methods, partial transmit sequence (PTS) and selective level mapping (SLM).Our simulation results show that 70% reduction in PAPR over original value in case of LDPC codes and 36% in case of PTS method and 23%in case of SLM method.