Improving capacity and QoS of VoIP in IEEE 802.11e wireless LANs
Mobility '08 Proceedings of the International Conference on Mobile Technology, Applications, and Systems
Fast track article: Backlogged queue based MAC frame aggregation
Pervasive and Mobile Computing
Leveraging 802.11n frame aggregation to enhance QoS and power consumption in Wi-Fi networks
Computer Networks: The International Journal of Computer and Telecommunications Networking
iVoIP: an intelligent bandwidth management scheme for VoIP in WLANs
Wireless Networks
| Hi-index | 0.07 |
The bandwidth efficiency of voice over IP (VoIP) traffic on the IEEE 802.11 WLAN is notoriously low. VoIP over 802.11 incurs high bandwidth cost for voice frame packetization and MAC/PHY framing, which is aggravated by channel access overhead. For instance, 10 calls with the G.729 codec can barely be supported on 802.11b with acceptable QoS - less than 2% efficiency. As WLANs and VoIP services become increasingly widespread, this inefficiency must be overcome. This paper proposes a solution that boosts the efficiency high enough to support a significantly larger number of calls than existing schemes, with fair call quality. The solution comes in two parts: adaptive frame aggregation and uplink/downlink bandwidth equalization. The former reduces the absolute number of MAC frames according to the link congestion level, and the latter balances the bandwidth usage between the access point (AP) and wireless stations. When used in combination, they yield superior performance, for instance, supporting more than 100 VoIP calls over an IEEE 802.11b link. The authors demonstrate the performance of the proposed approach through extensive simulation, and validate the simulation through analysis.