Enhancement of Analytical OBR (Out of Band Radiation) and BER Calculation for Digital Au-dio-Video Broadcasting in Companded OFDM System using Non-Symmetric QAM/QPSK Tecniques

Companding transforms useful under assumption of infinite bandwidth. Under band limited conditions OBR parameter filters out. So bandwidth is a factor that decides the filter-ing out OBR on the performance of companded OFDM sys-tems. As a result filtering becomes essential under band lim-ited conditions in turn this does deteriorate the system per-formance significantly. In this paper method proposed to overcome the performance degradation. Method called non symmetric scheme based on the use of curve fitting method to find out a suitable polynomial to be used for decom-panding at the receiver. This method indeed improves the performance in comparison to existing symmetric methods when filtering is necessary for band limited conditions