BER analysis of CVSD vocoder for WiMAX using GNU Radio

Abstract

An OFDM based WiMAX physical layer combining with Continuously Variable Slope Delta (CVSD) speech coding strategy has been implemented utilizing GNU Radio and USRP N210. CVSD vocoder is a non linear sampled data feedback framework which recognizes a band limited analog signal and converts it into binary form for transmission through a digital channel. The binary signal is decoded into a nearby estimate of original analog signal at the receiver. We executed a complete transceiver chain using testbed for WiMAX specifications. Further, we measure the performance of the testbed by evaluating error rate performance. The CVSD coding system is implemented in GNU Radio and the test outcomes demonstrated that coding has better Bit Error Rate (BER) and Symbol Error Rate (SER) values when integrated with FEC (Forward Error Correction). FEC has been carried out by linking convolutional coder (CCSDS coder) and Reed Muller (RM) coders.