VoIP Aggregation in Wireless Backhaul Networks

The newly emerging wireless backhaul network has fundamental difficulties in supporting Voice over IP (VoIP) applications due to the MAC overheads introduced by huge amounts of small packets. Packet aggregation is a promising approach to mitigate these overheads. However, previous approaches to such problems are often stringent, not adaptive to the change of channel conditions. They are operated by each TAP (Transit Access Point) separately without any coordination in the use of shared channels. As a result, they fail to ensure the VoIP quality in terms of delay and loss. The major contribution of this paper is the proposal of a coordinated aggregation algorithm, which is adaptive and distributed. By coordinating with neighboring TAPs, the proposed algorithm is able to assign an appropriate aggregation rate to each TAP, aiming at better channel utilization and lower packet loss and delay. We evaluate this design by comprehensive analysis and simulations. The simulation results show that our algorithm significantly improves the VoIP capacity in wireless backhaul networks and outperforms existing aggregation algorithms.