A Virtual Multiple Terminal Scheduling Scheme in the Infrastructure Based Wireless LAN to Enhance the VoIP Capacity

A virtual multiple terminal scheduling (VMTS) algorithm inside the access point is introduced for the infrastructure based wireless LAN. In such networks, downlink traffic loads transmitted by the access point are usually far more than those of any user wireless terminal. The asymmetric traffic loads make the access point the bottleneck. The proposed VMTS algorithm models multiple queues and backoff instances to contend the shared wireless channel simultaneously. VMTS scheme brings dynamical and self-adapted capacity for the access point and thus improves the performances (especially for downlink traffic) and fairness of the wireless network. Simulation results show that VMTS enhances the maximum VoIP capacity by above 14% for pure voice traffic loads compared with the original IEEE 802.11b network.