US Patent 7706399 Polling in wireless networks

Access points in wireless networks provide contention free access to stations through polling. Polling frames are transmitted to stations at polling intervals. Stations may transmit polling alignment requests to the access point to request a modification of the polling interval. Virtual polling is provided by publishing a virtual polling schedule. Stations respond to the virtual polling schedule without receiving polling frames. Polling intervals used during virtual polling may be modified in response to polling alignment requests from mobile stations.