Study on mechanism and reduction approaches of delay spikes occurrence on mobile networks

Since smartphones have spread and the transmission rate of mobile networks has accelerated, a lot of VoIP services are provided on mobile networks. Voice quality degradation due to delay spikes (i.e. sudden large increases in the packet delay) is the key issue for VoIP on mobile networks. To resolve this issue, adaptive jitter buffer control methods have been proposed to deal with delay spikes. These methods control the length of the jitter buffer in order to reduce voice quality degradation due to delay spikes. For further improving the quality of voice communication, it is effective to reduce the number of delay spikes. This paper analyzes the mechanism of delay spikes occurrence and proposes delay spike reduction approaches by controlling size and interval of voice packets on the basis of radio quality. Simulation results on the network simulator (ns-3) show the proposed approaches reduce the number of delay spikes by more than 50%.