Seamless mobility in wireless networks
View Patent ↗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 1 st 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 2 nd 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”.
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;
operating those communication links according to a protocol in which each wireless device selects access points with which to communicate;
wherein those steps of operating include causing a system coordinator to select information sent by those access points,
wherein said wireless devices have identifiers maintained at said access points, as selected by said system coordinator, with the effect that said system coordinator directs wireless devices to communicate with its selected access points by manipulation of said identifiers;
with the effect that wireless devices direct their communications to access points chosen by the system coordinator,
maintaining a first substantially unique identifier for each wireless device;
associating that first substantially unique identifier with at least one of a plurality of access points to communicate with a particular wireless device;
wherein that first substantially unique identifier is associated substantially only with those access points the system coordinator selects for communication with the wireless device;
maintaining a second substantially unique identifier, logically distinct from the first substantially unique identifier, at those access points;
maintaining a bit mask at those access points;
wherein a bitwise logical operation applied to the first substantially unique identifier and the bit mask yields the second substantially unique identifier associated with the particular wireless device.
2. A method as in claim 1 , including steps of
maintaining said first unique identifier for each wireless device, the identifier being maintained at a plurality of access points;
associating said at least one of those access points to communicate with a particular wireless device, and to cause said particular wireless device to communicate only with said at least one of those access points.
3. A method as in claim 2 , including steps of reassociating a first one of said access points with a distinct second access point to communicate with the particular wireless device.
4. A method as in claim 3 , wherein said second access point is substantially co-located with a target of those steps of reassociating.
5. A method as in claim 3 , wherein those steps of reassociating are responsive to changed communication conditions with the particular wireless device.
6. 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;
whereby multiple access points appear to wireless devices, according to the protocol, to be substantially identical.
7. 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;
whereby access points send fewer messages, according to the protocol, than the number of those identifiers.
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 9 , wherein those communication parameters include
at least one of
access control, backoff or retry parameters, channel selection parameters, quality of service, transmit power.
11. A method as in claim 1 , including steps of
reassociating that at least one access point with a distinct access point to communicate with the particular wireless device.
12. 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 send those messages using data rates responsive to the number of those identifiers.
13. 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.
14. A method as in claim 1 , wherein that first substantially unique identifier is unique only for a union of reception regions of access points relatively near the particular wireless device.
15. A method as in claim 1 , wherein that first substantially unique identifier describes one or more mobility domains for wireless devices.
16. A method as in claim 15 , including steps of dynamically altering a number of those mobility domains.
17. A method as in claim 15 , including steps of associating a separate communication channel to each of those mobility domains.
18. A method as in claim 15 , including steps of causing the wireless device to initiate a handoff when it is transferred from a first one to a second one of those mobility domains.
19. A method as in claim 15 , including steps of causing the wireless device to be transferred from a first one to a second one of those mobility domains, at the discretion of the system coordinator.
20. A method as in claim 15 , including steps of causing the wireless device to be transferred from a first one to a second one of those mobility domains, in response to at least one of the following
a change in conditions of communication with the wireless device, load balancing,
movement of the wireless device,
a request for service by the wireless device.
21. A method as in claim 15 , wherein those mobility domains are substantially co-located.
22. A method as in claim 21 , including steps of causing the wireless device to be transferred from a first one to a second one of those mobility domains without any movement by the wireless device.
23. A method as in claim 21 , including steps of causing the wireless device to be transferred from a first one to a second one of those mobility domains without any change in access assigned to the wireless device.
24. A method as in claim 1 , wherein that first substantially unique identifier includes a substantially disjoint information cluster for each combination of wireless device and service coupled to the first and second one of that plurality of access points.
25. A method as in claim 24 , wherein that substantially disjoint information cluster is primarily described by a bit assigned to the particular wireless device.
26. A method as in claim 24 , including steps of dynamically altering a number of those bits.
27. A method as in claim 24 , wherein that substantially disjoint information cluster is also primarily described by a bit assigned to the particular first or second one of that plurality of access points.
28. A method as in claim 1 , wherein
the second substantially unique identifier includes substantially all zero bits; and
the bit mask includes substantially all one bits except for substantially disjoint sets of bits separately associated with each particular wireless device.
29. A method as in claim 1 , wherein
the second substantially unique identifier includes substantially all zero bits; and
the bit mask includes substantially all one bits except for substantially those bits separately associated with each particular wireless device.
30. 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,
wherein said system coordinator directs wireless devices to communicate with designated access points by manipulation of said selected information;
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,
a physical medium including information readable by a computing device, the information including a first substantially unique identifier for each wireless device, the identifier for a particular wireless device being maintained at one or more of those access points; wherein
that first substantially unique identifier is maintained substantially only at those access points the system coordinator selects for communication with the wireless device;
a physical medium including information readable by a computing device, the information including instructions interpretable by a computing device to
maintain a second substantially unique identifier, logically distinct from the first substantially unique identifier, at those access points; and
maintain a bit mask at those access points;
wherein a bitwise logical operation applied to the first substantially unique identifier and the bit mask yields the second substantially unique identifier associated with the particular wireless device.
31. Apparatus as in claim 30 , wherein in said physical medium including information readable by a computing device, the information including a first substantially unique identifier for a wireless device, said information includes said first substantially unique identifier 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 those at least one associated access point communicates with that particular wireless device.
32. Apparatus as in claim 31 , 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.
33. Apparatus as in claim 31 , 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.
34. Apparatus as in claim 33 , wherein those communication parameters include
at least one of
access control, backoff or retry parameters, channel selection parameters, quality of service, transmit power.
35. Apparatus as in claim 30 , wherein that first substantially unique identifier is unique only for a union of reception regions of access points relatively near the particular wireless device.
36. Apparatus as in claim 30 , wherein that first substantially unique identifier describes one or more mobility domains for wireless devices.
37. Apparatus as in claim 36 , wherein that mobility domain describes a separate communication channel.
38. Apparatus as in claim 36 , wherein those mobility domains are substantially co-located.
39. Apparatus as in claim 30 , wherein that substantially unique identifier includes a substantially disjoint information cluster for each combination of wireless device and service coupled to the first and second one of that plurality of access points.
40. Apparatus as in claim 39 , wherein that substantially disjoint information cluster is primarily described by a bit assigned to the particular wireless device.
41. Apparatus as in claim 39 , wherein that substantially disjoint information cluster is also primarily described by a bit assigned to the particular first or second one of that plurality of access points.
42. Apparatus as in claim 30 , wherein
the second substantially unique identifier includes substantially all zero bits; and the bit mask includes substantially all one bits except for substantially disjoint sets of bits separately associated with each particular wireless device.
43. Apparatus as in claim 30 , wherein
the second substantially unique identifier includes substantially all zero bits; and the bit mask includes substantially all one bits except for substantially those bits separately associated with each particular wireless device.