Quality of Service Improvement for Voice Streaming over Wireless Ad-hoc Networks using an Adaptive Playout Adjustment Algorithm

Providing a high-quality service for transmission and playing real-time voice conversations (voice streaming) over wireless ad-hoc networks is no mean feat. Buffering together with adjusting the playout time of the packets is a receiver-side solution to overcome this challenge. In this paper, a new adaptive playout adjustment algorithm is proposed to stream the voice conversations over wireless ad-hoc networks. This algorithm always tries to be aware of the network s conditions, adapts itself with these conditions and adjusts the playout time of the voice packets as efficiently as possible. It is required that not only most of the packets be received before their playout time, as scheduled in the receiver, but also that the playout time not be too long so as to adversely affect the interactivity between the sender and the receiver. The main features of the presented method are: adjusting the threshold adaptively with respect to the varying conditions of the network in order to determine the state of system; calculating the mean network jitter dynamically based on the current conditions of the network in order to calculate the playout delay for the current packet; being optimistic about the future state of the network and not using the delay history in order to calculate the mean network delay. Simulation results show that the proposed algorithm adapts itself with the network s dynamics and adjusts the playout delay for voice packets better than the other algorithms.

کلیدواژه ها:

Wireless Mobile Ad-hoc Networks ، Voice Streaming ، Adaptive Playout Algorithm ، Quality of Service ، Multimedia