Comparison analysis of OFDM signal performance with Cyclic prefix and LDPC codes over AWGN channel

Orthogonal frequency division multiplexing has a high tolerance to multipath signals and is spectrally efficient making it good candidate high data rate systems. It is a very promising technology using adaptive rate algorithm serves well to improve performance. It appears to be a good modulation technique for high performance systems but still it has drawback such as high peak to average power ratio (PAPR) which can be reduced by use of various techniques PTS(Partial transmit sequence), Cyclic prefix and PRC (Peak reduction carriers). In this paper cyclic prefix method and a most efficient LDPC (Low density parity check) codes are compared to reduce the problem of PAPR. For LDPC codes at the receiver end the received message is decoded using Log domain algorithm and performance is analysed. Graph is observed between BER of cyclic prefix and LDPC codes using BPSK modulation over AWGN channel for constant Eb/No. of 3 dB.