Enhanced upstream scheduling algorithm for variable bit rate VoIP service over hybrid fiber coaxial network

In this paper, we enhance the existing upstream scheduling algorithm for VoIP service in data-over-cable system interface specification (DOCSIS) MAC protocol which is, called unsolicited grant service with activity detection (UGS-AD), not able to efficiently support various VoIP codecs with variable bit rate (VBR) and silence suppression over the shared medium hybrid-fiber-coaxial (HFC) network. We modify the UGS-AD to minimize a waste of uplink resources for supporting the VBR VoIP service. This proposed scheme is compared with the existing UGS-AD through the capacity analysis. Results show that our proposed algorithm can support more up to 59% voice users compared with the existing UGS-AD.