Synchronization of multiple access points in the IEEE 802.11 point coordination function

Guaranteed QoS in WLAN can enable the support of new and demanding services. The IEEE 802.11 WLAN is the dominant solution for local area wireless networking, as it can provide low cost and easy to deploy high performance wireless connectivity. IEEE has defined two access methods for the 802.11 WLAN: DCF and PCF. Even though the DCF access mode can provide high throughput and low delay for a limited number of users, only the PCF access mode can deliver guaranteed quality of service when the number of users increases. The PCF access mode, as defined by IEEE, cannot operate efficiently when a number of access points with overlapping coverage areas communicate over the same channel. In this paper a new intra access point synchronization scheme is introduced, for allowing multiple access points to cooperate, providing guaranteed quality of service under the PCF operation.