Digital multicarrier modulation techniques for high data rates multimedia applications in present and future wireless communication systems

To accommodate high performance and high bit rates for multimedia applications in present and future wireless communication systems, it is essential that modulation techniques applied in this scenario are able to support high data rates upto and above 200 Mbps. To meet the increased demand of higher bit rates, the wireless systems are incorporating the multi-carrier modulation techniques ,such as FFT based MCM which is also known as conventional OFDM and wavelet transform based MCM. Wireless multicarrier modulation is a technique of transmitting data by dividing the input data stream into parallel sub-streams that are each modulated and multiplexed onto the channel at different carrier frequencies. In this paper, we studied the performance of DWT based MC-CDMA and FFT based MCCDMA modulations for transmission over wireless fading channels. This scheme is shown to be overall quite similar to FFT based OFDM modulation, but with some interesting additional features and improved characteristics. Results shows that DWT based MCCDMA modulation has better bit error rate (BER) performance than conventional FFT based CDMA without cyclic prefix (CP) for all signal-to-noise ratios and also outperforms FFT based CDMA for low signal-to-noise ratio values.