A Silence Duration Based Uplink Scheduling Algorithm for Multiple VoIP Users in M-WiMAX

Abstract

This paper proposes an efficient uplink scheduling algorithm that can perfectly support various VoIP CODECs with VAD/DTX/CNG in M-WiMAX considering the variants of silence duration between different voice users, solving the problems of uplink resources wastes and overwhelmingly large overhead that caused during silence period. In our proposed algorithm, efficient schemes is proposed to implement the uplink resource interval and allocation procedure, and the BS adapts this uplink resources interval according to the reserved bit in the generic MAC header of IEEE802.16e, which is utilized to indicate voice activity of each voice user . The performance analysis of the conventional algorithms (UGS, rtPS and ertPS) as well as the one proposed in this paper is also provided. Through the numerical validations, proposed algorithm performs efficiently than the conventional algorithms over enhancement of resource utilization, total throughput, and system capacity. Also, it is proved that our algorithm can support more voice users than the conventional algorithms.

Improving ertPS Grant Allocation for VoIP Traffic inSilence Duration

“…For the first scenario we know that increasing the grant interval in silence duration increasing capacity [7]. But the delayed packets can decrease the voice quality by increasing the delay and jitter.…”

“…Different grant allocation interval schemes were proposed for scheduling ertPS uplink channel in silence duration. Reference [7] proposed three methods: 1) Maximum Interval (MI): In this case the BS applies the maximum increment grant interval scheme:…”

“…In [6] a scheduling algorithm that is suitable for adaptive multi-rate (AMR) CODEC is introduced. In [7], users are divided into two categories based on average silence duration. Grant interval time scheme is selected by related category.…”