Analysis of BER for M-QAM and QOS Enhancement for OFDM Systems

Orthogonal frequency division multiplexing (OFDM) technique has been widely adopted in many wireless communication systems due to its high data-rate transmission ability and robustness to the multipath fading channel. One of the major drawbacks of OFDM signal is the high peak-to-average power ratio (PAPR). In this paper, a software reference model for OFDM is developed and verified for its functionality that can be adopted for wireless communication applications. Bit error rate (BER) and functionality of the developed OFDM model is analyzed for 16-QAM, 64-QAM, and 256 QAM. We present a technique to reduce the BER of the transmitted signals and hence reduce the PAPR by introducing sequences. We propose a reliable BER reducing method that consists in putting together a Golay sequence with the input sequence. This new method offers competitive performance as well as low BER compared to previously published methods. Computer simulation for a standard OFDM system shows BER reduction by comparison to the competitive methods.