Wireless communication methods and components that implement handoff in wireless local area networks

Abstract

This invention relates to wireless local area networks, and particularly to the IEEE 802.11 family of standards. It consists of a method and apparatus that can be implemented in access points (APs) and subscriber wireless transmit/receive units (WTRUs), in order to allow an AP to initiate re-association of a WTRU to itself or a different AP. The invention improves the robustness of the network by enabling more efficient load balancing, congestion control, and roaming, without compromising the user experience.

1 .- 25 . (canceled) 
     
     
         26 . A method for use in a wireless transmit/receive unit (WTRU), the method comprising:
 receiving, from an Institute of Electrical and Electronics Engineers (IEEE) 802.11 access point (AP), a request message on a first channel associated with a first set of communication parameters;   determining whether to accept or reject association with the IEEE 802.11 AP on a second channel based on the request message;   transmitting a response message to the IEEE 802.11 AP using the first set of communication parameters, wherein the response message indicates whether the WTRU accepts or rejects association with the IEEE 802.11 AP on the second channel; and   on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, reconfiguring to communicate via a second set of communication parameters, and communicating with the IEEE 802.11 AP using the second set of communication parameters.   
     
     
         27 . The method of  claim 26 , wherein the request message includes: an identifier of the IEEE 802.11 AP on the second channel, the second set of communication parameters, and a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         28 . The method of  claim 26 , further comprising:
 on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, transmitting a notification message to the IEEE 802.11 AP using the first set of communication parameters, wherein the notification message indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate.   
     
     
         29 . The method of  claim 27 , wherein the identifier of the AP is a Basic Service Set Identifier (BSSID). 
     
     
         30 . The method of  claim 26 , wherein the second set of communication parameters includes an indication of the second channel of the IEEE 802.11 AP. 
     
     
         31 . The method of  claim 26 , wherein the request message is a management frame. 
     
     
         32 . The method of  claim 26 , wherein the request message includes a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         33 . A wireless transmit/receive unit (WTRU), the WTRU comprising:
 a transceiver configured to receive from an Institute of Electrical and Electronics Engineers (IEEE) 802.11 access point (AP), a request message on a first channel associated with a first set of communication parameters;   a processor configured to determine whether to accept or reject association with the IEEE 802.11 AP on a second channel based on the request message;   the transceiver further configured to transmit a response message to the IEEE 802.11 AP using the first set of communication parameters, wherein the response message indicates whether the WTRU accepts or rejects association with the IEEE 802.11 AP on the second channel; and   on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, the transceiver further configured to communicate with the IEEE 802.11 AP using a second set of communication parameters.   
     
     
         34 . The WTRU of  claim 33 , wherein the request message includes: an identifier of the IEEE 802.11 AP on the second channel, the second set of communication parameters, and a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         35 . The WTRU of  claim 33 , further comprising:
 on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, the transceiver further configured to transmit a notification message to the IEEE 802.11 AP using the first set of communication parameters, wherein the notification message indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate.   
     
     
         36 . The WTRU of  claim 34 , wherein the identifier of the AP is a Basic Service Set Identifier (BSSID). 
     
     
         37 . The WTRU of  claim 33 , wherein the second set of communication parameters includes the second channel of the IEEE 802.11 AP. 
     
     
         38 . The WTRU of  claim 33 , wherein the request message is a management frame. 
     
     
         39 . The WTRU of  claim 33 , wherein the request message includes a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         40 . A method for use in an Institute of Electrical and Electronics Engineers (IEEE) 802.11 access point (AP), the method comprising:
 sending a request message to a wireless transmit/receive unit (WTRU) on a first channel associated with a first set of communication parameters;   receiving a response message from the WTRU on the first channel associated with the first set of communication parameters, wherein the response message indicates whether the WTRU accepts or rejects association with the IEEE 802.11 AP on a second channel; and   on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, communicating with the WTRU using a second set of communication parameters.   
     
     
         41 . The method of  claim 40 , wherein the request message includes: an identifier of the IEEE 802.11 AP on the second channel, the second set of communication parameters, and a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         42 . The method of  claim 40 , further comprising:
 on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, receiving a notification message from the WTRU using the first set of communication parameters, wherein the notification message indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate.   
     
     
         43 . The method of  claim 41 , wherein the identifier of the AP is a Basic Service Set Identifier (BSSID). 
     
     
         44 . The method of  claim 40 , wherein the second set of communication parameters includes the second channel of the IEEE 802.11 AP. 
     
     
         45 . The method of  claim 40 , wherein the request message is a management frame. 
     
     
         46 . The method of  claim 40 , wherein the request message includes a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         47 . An Institute of Electrical and Electronics Engineers (IEEE) 802.11 access point (AP), the AP comprising:
 a transceiver configured to send a request message to a wireless transmit/receive unit (WTRU) on a first channel associated with a first set of communication parameters;   the transceiver further configured to receive a response message from the WTRU on the first channel associated with the first set of communication parameters, wherein the response message indicates whether the WTRU accepts or rejects association with the IEEE 802.11 AP on a second channel; and   on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, the transceiver further configured to communicate with the WTRU using a second set of communication parameters.   
     
     
         48 . The AP of  claim 47 , wherein the request message includes: an identifier of the IEEE 802.11 AP on the second channel, the second set of communication parameters, and a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate. 
     
     
         49 . The AP of  claim 47 , further comprising:
 on a condition the WTRU accepts association with the IEEE 802.11 AP on the second channel, the transceiver further configured to receive a notification message from the WTRU using the first set of communication parameters, wherein the notification message indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate.   
     
     
         50 . The AP of  claim 48 , wherein the identifier of the AP is a Basic Service Set Identifier (BSSID). 
     
     
         51 . The AP of  claim 47 , wherein the second set of communication parameters includes an indication of the second channel of the IEEE 802.11 AP. 
     
     
         52 . The AP of  claim 47 , wherein the request message is a management frame. 
     
     
         53 . The AP of  claim 47 , wherein the request message includes a field that indicates whether disassociation of the WTRU from the IEEE 802.11 AP on the first channel is immediate.