Scheduling for VoIP Service in cdma2000 1x

Abstract — Recently cdma2000 1x EV-DO (HDR) system has begun to be deployed in some countries to support high data rate services in cellular networks. The system is originally designed to support data services, but now is expected to serve some real-time traffic including VoIP. For VoIP service with delay bound and low loss requirements, we propose a frame structure considering delay bound and a scheduling algorithm reflecting channel conditions. To schedule VoIP, we adopt the maximal rate algorithm and the proportionally fair algorithm. The proportionally fair algorithm (PF) was known to be appropriate for elastic traffic, however, from simulation results, we conclude that the PF algorithm with the channel test is an appropriate scheduling scheme to provide QoS of VoIP. When the required slot portion of VoIP is 75%, the loss rate is about 1 % on the average and 3% in the worse case. On the other hand, the maximal rate algorithm shows twice of the loss rate for the same delay bound and load. Additionally we propose a simple admission control scheme for VoIP service that controls the average portion of slots occupied by VoIP packets. I