Seamless mobility in wireless networks

Abstract

AP's associated with a communication network and any wireless devices desiring contact, operated according to a protocol in which each wireless device selects AP's with which to communicate. A system coordinator causes the AP's to operate so as to guide each wireless device to an AP selected by the system coordinator. This has the effect that, notwithstanding that the protocol involves having the wireless device make the selection of AP, functionally, the AP's make the selection for it. In a 1st technique, multiple AP's share an identifier, with the system coordinator directing one particular AP to respond to the wireless device, thus appearing to wireless devices as a “personal cell”. In a 2nd technique, AP's each maintain identifiers substantially unique to each wireless device, with the system coordinator directing only one particular AP to maintain any particular wireless device's identifier, thus appearing to wireless devices as a “personal AP”.

What is claimed: 
     
         1 . A method, including steps of:
 providing a set of communication links between access points associated with a communication network and any wireless devices desiring contact with that communication network;   maintaining an identifier for each wireless device, the identifier being maintained at a plurality of access points;   associating at least one of those access points to communicate with a particular wireless device;   sending, from each access point, messages to be received by wireless devices, indicating availability of multiple identifiers; whereby multiple access points appear to wireless devices, according to the protocol, to be substantially identical, and   causing a system coordinator to select information sent by the access points, with the effect that wireless devices direct their communications to access points chosen by the system coordinator.   
     
     
         2 . A method as in  claim 1 , including steps of reassociating that access point with a distinct access point to communicate with the particular wireless device. 
     
     
         3 . A method as in  claim 2 , wherein that access point is substantially colocated with a target of those steps of reassociating. 
     
     
         4 . A method as in  claim 2 , wherein those steps of reassociating are responsive to changed communication conditions with the particular wireless device 
     
     
         8 . A method as in  claim 2 , including steps of sending, from each access point, messages to be received by wireless devices, indicating availability of multiple identifiers; wherein access points send those messages using data rates responsive to the number of those identifiers. 
     
     
         9 . A method as in  claim 2 , including steps of sending, from each access point, messages to be received by wireless devices, indicating availability of multiple identifiers; wherein access points customize those messages in response to first and second sets of communication parameters to be established with first and second wireless devices. 
     
     
         10 . A method as in  claim 1  including steps of:
 sending, from each access point, messages to be received by wireless devices, indicating availability of multiple identifiers; wherein access points customize those messages in response to first and second sets of communication parameters to be established with first and second wireless devices. 
 
     
     
         11 . A method as in  claim 10 , wherein those communication parameters include at least one of access control, backoff or retry parameters, channel selection parameters, quality of service, transmit power. 
     
     
         12 . Apparatus including:
 a set of access points associated with a communication network, operating according to a protocol in which wireless devices seeking or having access to the communication network select those access points with which to communicate; and   a system coordinator coupled to those access points and including a physical medium including information readable by a computing device, the information including instructions for directing those access points to send selected information according to that protocol, the selected information having the effect that wireless devices operating according to that protocol select substantially only those access points intended by the system coordinator.   
     
     
         13 . Apparatus as in  claim 12 , including:
 a physical medium including information readable by a computing device, the information including an identifier for a wireless device, the identifier for a particular wireless device being maintained at a plurality of access points;   wherein the system coordinator includes instructions interpretable by a computing device to associate at least one of those access points to communicate with a particular wireless device;   whereby substantially only that associated access point communicates with that particular wireless device.   
     
     
         14 . Apparatus as in  claim 13 , including at substantially each access point:
 a physical medium including information readable by a computing device, the information including a formatted message to be received by wireless devices, the message indicating availability of multiple identifiers; whereby access points send fewer messages, according to the protocol, than the number of those identifiers.   
     
     
         15 . Apparatus as in  claim 12 , including a physical medium including information readable by a computing device, the information including a substantially unique identifier for each wireless device, the identifier for a particular wireless device being maintained at one or more of those access points; where-in that substantially unique identifier is maintained substantially only at those access points the system coordinator selects for communication with the wireless device. 
     
     
         16 . Apparatus as in  claim 15 , wherein that substantially unique identifier is unique only for a union of reception regions of access points relatively near the particular wireless device. 
     
     
         17 . Apparatus as in  claim 12 , including at substantially each access point, a physical medium including information readable by a computing device, the information including a formatted message to be received by wireless devices, the message indicating availability of multiple identifiers; whereby access points send fewer messages, according to the protocol, than the number of those identifiers. 
     
     
         18 . Apparatus as in  claim 12 , including at substantially each access point, a physical medium including information readable by a computing device, the information including a formatted message to be received by wireless devices, the message indicating availability of multiple identifiers; wherein the message is customized in response to first and second sets of communication parameters to be established with first and second wireless devices. 
     
     
         19 . Apparatus as in  claim 12 , including at substantially each access point, a physical medium including information readable by a computing device, the information including a formatted message to be received by wireless devices, the message indicating availability of multiple identifiers; wherein the message is customized in response to first and second sets of communication parameters to be established with first and second wireless devices. 
     
     
         20 . Apparatus as in  claim 19 , wherein those communication parameters include at least one of access control, backoff or retry parameters, channel selection parameters, quality of service, transmit power.