Patent ID: 7925263

Claim:
A method for triggering a handoff by a wireless transmit/receive unit (WTRU) from a current basic service set (BSS) in a wireless local area network (WLAN), comprising: determining a highest class of traffic service and quality of service (QoS) for the highest class from a basic service set (BSS) beacon; terminating a handoff and retaining communication with the current BSS when the signal to noise ratio (SNR) or received signal strength (RSS) is greater than a high threshold of the highest class; calculating a quality of service (QoS) index by: setting a QoS index to zero; creating a list of QoS parameters; selecting one of the QoS parameters; comparing the selected QoS parameter with a high threshold for that QoS parameter; and incrementing the QoS index when the selected QoS parameter exceeds the high threshold for that QoS parameter; retaining the current QoS index when the selected QoS parameter equals the high threshold for that QoS parameter, and decrementing the QoS index when the selected QoS parameter is less than the high threshold for the selected QoS parameter; determining a QoS index difference value between the selected BSS and the current BSS and comparing the QoS index difference value with a hysteresis; updating the hysteresis value on a condition that the QoS index difference value is smaller than the hysteresis; defining a minimum and maximum value of delay bounds, bandwidth requirements, and frame error rate for a plurality of traffic classes; and evaluating the delay bounds, bandwidth requirements, and frame error rate to determine whether a handoff is desired when the SNR or RSS is less than the high threshold.