Seamless roaming among multiple networks

• US 6,154,461 A
• Filed: 05/14/1997
• Issued: 11/28/2000
• Est. Priority Date: 05/14/1997
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Telxon Corporation (Zebra Technologies Corporation)
• Inventors: Sturniolo, Emil A., Ciotti, Frank D. Jr., Seshadri, Krishna P.
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): Duong, Frank
• Application Number:
  US08/856,122
• Time in Patent Office: 1,294 Days
• Field of Search: 370/310, 370/328, 370/338, 370/401, 370/402, 370/403, 370/404, 370/349, 370/473, 455/432, 455/550, 455/556, 455/561, 455/575
• US Class Current: 370/401
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/148 Migration or transfer of sessions
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/087 for preserving data network PoA address despite hand-offs
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

The present invention relates to wireless communication systems involving multiple local area networks. A communication system according to the present invention includes a plurality of local area networks (LANs). Each of the LANs includes: a network backbone; and at least one access point coupled to the network backbone which, when a mobile terminal is registered to the access point, enables the mobile terminal to communicate wirelessly with a device on the network backbone via the at least one access point. When the mobile terminal is registered to at least one access point in one of the plurality of LANs the mobile terminal is assigned a first network address, and when the mobile terminal is registered to at least one access point in another of the plurality of LANs the mobile terminal is assigned a second network address in place of the first network address, the second network address being different from the first network address. The mobile communication system also includes a system backbone interconnecting the plurality of LANs for permitting communications between the plurality of LANs. Furthermore, the system includes a gateway controller, operatively coupled to one of the plurality of LANs, for serving as an intermediary for communications between the mobile terminal and a device on one of the system backbones in order that in the event the mobile terminal is assigned a different network address by virtue of registering with an access point in another of the LANs, the device is able to maintain communications with the mobile terminal without requiring knowledge of a change in the network address of the mobile terminal.

Claims

1. A communication system, comprising:

a plurality of local area networks (LANs), each of the LANs including;

a network backbone; and

at least one access point coupled to the network backbone which, when a mobile terminal is registered to the access point, enables the mobile terminal to communicate wirelessly with a device coupled to the network backbone via the at least one access point;

wherein when the mobile terminal is registered to at least one access point in one of the plurality of LANs the mobile terminal is assigned a first network address, and when the mobile terminal is registered to at least one access point in another of the plurality of LANs the mobile terminal is assigned a second network address in place of the first network address, the second network address being different from the first network address;

a system backbone interconnecting the plurality of LANs for permitting communications between the plurality of LANs;

a gateway controller, operatively coupled to one of the plurality of LANs, for serving as an intermediary for communications between the mobile terminal and a device on one of the system backbones in order that in the event the mobile terminal is assigned a different network address by virtue of registering with an access point in another of the LANs, the device is able to maintain communications with the mobile terminal without requiring knowledge of a change in the network address of the mobile terminal; and

the gateway controller storing information relating to the current network address of the mobile terminal and the current network address of the device, wherein the gateway controller receives communications from the mobile terminal containing information intended for the device and forwards the information to the device, and the gateway controller receives communications from the device containing information intended for the mobile terminal and forwards the information to the mobile terminal.

2. The communication system of claim 1, wherein each of the plurality of LANs includes a gateway controller connected to the system backbone.

3. The communication system of claim 1, wherein the system backbone represents part of a wide area network (WAN).

4. The communication system of claim 1, wherein the mobile terminal comprises at least one of a data terminal, a telephone, and a pager.

5. A gateway controller for use in a communication system including a plurality of local area networks (LANs), each of the LANs including a network backbone;

and at least one access point coupled to the network backbone which, when a mobile terminal is registered to the access point, enables the mobile terminal to communicate wirelessly with a device on the network backbone via the at least one access point, the gateway controller comprising;

means for operatively coupling the gateway controller to the network backbone of a selected one of the plurality of LANs;

a gateway address circuit for communicating with a mobile terminal registered with the access point of the selected LAN via the network backbone for establishing indica distinguishing the mobile terminal from among other mobile terminals;

a communication circuit for receiving communications from the registered mobile terminal intended for the device and forwarding the received communications to the device together with at least part of the indicia as provided by the communication circuit, and for receiving communications, including the at least part of the indicia, from the device intended for the registered mobile terminal and forwarding the received communications to the registered mobile terminal based on the at least part of the indicia.

6. The gateway controller of claim 5, wherein the indicia represents a layer of addressing utilized in communications involving the gateway controller and the registered mobile terminal but which is not required in communications between other devices communicating on the network backbone.

7. The gateway controller of claim 6, wherein the layer of addressing permits the device wirelessly communicating with the mobile terminal to continue communicating with the registered mobile terminal even if another layer of addressing for the registered mobile terminal changes unbeknownst to the device.

8. The gateway controller of claim 5, wherein the indicia represents a plurality of layers of addressing utilized in communications involving the gateway controller and the registered mobile terminal but which are not required in communications between other devices communicating on the network backbone.

9. The gateway controller of claim 5, wherein the communication circuit includes a memory table in which the indicia for a plurality of mobile terminals are stored.

10. A network communication system, comprising:

a plurality of local area networks (LANs), each of the LANs including;

a network backbone; and

at least one access point coupled to the network backbone which, when a mobile terminal is registered to the access point, enables the mobile terminal to communicate wirelessly with the network backbone via the at least one access point;

a system backbone interconnecting the plurality of LANs for permitting communication between the plurality of LANs;

a gateway controller, operatively coupled to one of the plurality of LANs and able to communicate with devices on other of the plurality of LANs via the system backbone, the gateway controller serving as an intermediary for communications between the mobile terminal and a device on a first of the plurality of LANs;

the gateway controller assigning a gateway address to the mobile terminal such that once the mobile terminal starts a session with the device coupled to the first of the plurality of network backbones, the mobile terminal may continuously maintain the session through the gateway even if the mobile terminal registers with an access point coupled to another of the plurality of network backbones; and

the gateway controller storing information in association with the gateway address relating to the current network address of the mobile terminal and the current network address of the device, wherein the gateway controller receives communications from the mobile terminal containing information intended for the device and forwards the information to the device, and the gateway controller receives communications from the device containing information intended for the mobile terminal and forwards the information to the mobile terminal.

11. The network communication system of claim 10, wherein each of the plurality of LANs includes a gateway controller connected to the system backbone.

12. The network communication system of claim 10, wherein the system backbone represents part of a wide area network (WAN).

13. The network communication system of claim 10, wherein the mobile terminal comprises at least one of a data terminal, a telephone, and a pager.

14. A mobile terminal for use in a communication system including a plurality of local area networks (LANs), each of the LANs including a network backbone and at least one access point coupled to the network backbone which, when the mobile terminal is registered to the access point, enables the mobile terminal to communicate wirelessly with a device coupled to the network backbone via the at least one access point, the mobile terminal comprising:

mobile terminal address circuitry for establishing with a gateway controller coupled to one of the plurality of LANs via the network backbone indicia distinguishing the device from among other devices; and

a communication circuit for transmitting communications destined for the device to the gateway controller together with at least part of the indicia, and for receiving communications transmitted by the device and destined for the mobile terminal from the gateway controller, the received communications having the at least part of the indicia included by the gateway controller.

15. The mobile terminal of claim 14, wherein the indicia represents a layer of addressing utilized in communications between the mobile terminal and gateway controller for identifying the device.

16. The mobile terminal of claim 15, wherein the layer of addressing permits the device communicating with the mobile terminal to continue communicating with the mobile terminal through the gateway even if another layer of addressing of the mobile terminal changes unbeknownst to the device.

17. The mobile terminal of claim 14, wherein the mobile terminal address circuitry includes a memory table in which the indicia for a plurality of devices are stored.

18. A mobile terminal for use in a wireless communication system including a plurality of local area networks (LANs), each of the LANs including a network backbone and at least one access point coupled to the network backbone, the mobile terminal including:

a portable housing;

means for assigning unique indicia to a plurality of devices in the wireless communication system with which the mobile terminal desires to communicate; and

means for storing the unique indicia for the plurality of devices.

19. The mobile terminal of claim 18, further comprising a transceiver for wirelessly transmitting and receiving communications with at least one of the plurality of devices via a gateway controller coupled to the network backbone.

20. The mobile terminal of claim 19, wherein the communications received by the gateway controller from the one of the plurality of devices includes at least part of the unique indicia assigned to the one of the plurality of devices by the mobile terminal.

21. The mobile terminal of claim 20, wherein the unique indicia represents a layer of addressing utilized in communications between the mobile terminal and gateway controller.

22. The mobile terminal of claim 18, wherein the means for storing is a memory.