Channel-aware VoIP packet scheduling in cdma2000 1x EV-DO networks

As cellular networks are evolving into high data rate systems, cdma2000 1x EV-DO (HDR) has been highlighted and deployed for data-only wireless service. For wide applications, it is expected to serve some real-time traffic including VoIP. To meet the loss requirement and to ensure the delay bound of VoIP packets, we consider two scheduling algorithms that are channel-aware and flexible in the frame structure; maximal rate (MAX) algorithm and proportionally fair (PF) algorithm. The PF algorithm was known to be appropriate for elastic traffic, not real time traffic. However, through simulations, we find that the PF algorithm with a simple channel test can become a good approach for supporting VoIP users. When the required slot portion of VoIP is 75%, this algorithm obtains the loss rate of about 1% on the average and 3% in the worse case. On the other hand, the MAX algorithm shows twice of the loss rate when the same delay bound and load are given. These results provide an insight in designing a simple admission control scheme for VoIP users to control the average portion of slots occupied by VoIP packets.