Modified user-dependent perfect-scheduling multiple access protocol for WLAN

Based on effective contention access and perfect scheduling transmission, an enhanced multiple access protocol – UPMA++ protocol – is proposed. It allocates the resource dynamically according to the actual traffic requirement and does not require the synchronisation in the whole network. This protocol adjusts the length of contention access period and polling period effectively to resolve the conflicts between active stations and transmission stations. By analysis, the optimal contention access period length for the given polling period length is found, and the performance evaluations show that UPMA++ protocol has a high throughput, low average message delay and small average message dropping probability.