Investigating the performance of various vocoders for a fair scheduling algorithm in WiMAX

IEEE 802.16e, a broadband wireless access technology that provides high speed Internet access and multimedia services has seen very significant growth in recent times. With the due rapid deployment of WiMAX, there would be a growing demand for efficient support of voice applications. The performance of voice over IP services depends on a proper scheduling algorithm combined with a proper voice encoder scheme. The contribution of this work is two fold. The first is that we present an efficient scheduling algorithm that can be used for VoIP services in IEEE 802.16e. We then implement the algorithm in various CODECS and compare the performance of the codec's i.e.G.728, G.711, G.723, G.729, G.726, GSM-EFR, GSM-HR under similar load conditions for interactive voice over WiMAX by enabling the speech activity detection (SAD). We analyze the system throughput and delay to evaluate the performance of our algorithm and the primary metrics that were used in the comparison for choosing the right vocoders for the algorithm were jitter, MOS, and packet end to end delay.