Handoff control in an enterprise division multiple access wireless system

• US 7,965,685 B1
• Filed: 04/18/2005
• Issued: 06/21/2011
• Est. Priority Date: 09/05/2000
• Status: Active Grant

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Joo, Ki Hyun, Hyun, Sang Kyoon, Rha, Peter S., Kang, Chol Su
• Primary Examiner(s): Phunkulh; Bob A
• Application Number:
  US11/108,260
• Time in Patent Office: 2,255 Days
• Field of Search: None
• US Class Current: 370/331
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: H04W 4/04 using association of physical positions and logical data in a dedicated environment, e.g. buildings or vehicles
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A wireless office communication system including a wireless internet base station (WIBS) encompassing a base station controller, a mobile switch controller and an ethernet interface module for coupling the WIBS to an existing internet protocol (IP) based network. A wireless office communication system can also be based on the conventional architecture comprising the BTS, BSC and MSC. The WIBS or BTS is attached to a number of antennas via different and identifiable delay elements for the purpose of determining the serving antennas of mobile communication units. A location determination logic enables the system to handle handoffs between a WIBS or BTS and the external public communication system in an optimum manner. Handling handoff requests in this manner prevents unnecessary ping-ponging of handoff and can also increase the percentage of successful handoff by frequency monitoring of the quality of the mobile communication units located in the handoff transition area, particularly to the public communication system.

Claims

1. A wireless base station, comprising:

a base station controller operable to control communication between the wireless base station and a mobile communication unit within a coverage area associated with the wireless base station;

a plurality of antenna units operable to receive wireless signals from the mobile communication unit and to transmit wireless signals to the mobile communication unit;

a plurality of delay units, each of the plurality of delay units associated with a selected one of the antenna units, each of the plurality of delay units operable to insert an amount of delay time into a communication that is distinguishable from an amount of delay time inserted by each other delay unit; and

user location identification logic operable to;

receive a handoff request from the mobile communication unit;

based on the delay time associated with a handoff request, determine a location of the mobile communication unit by identifying an antenna unit associated with a delay unit associated with the delay time;

decide whether the location of the mobile communication unit is within a designated handoff area;

execute a handoff between a first network and a second network, if the location of the mobile communication unit is within the designated handoff area; and

deny the handoff request if the location of the mobile communication unit is not within the designated handoff area.

2. The wireless base station of claim 1, wherein wherein each of the plurality of antenna units couples to the base station controller through one or more delay units.

3. The wireless base station of claim 2, wherein the user identification logic is further operable to determine the determine the antenna unit serving the mobile communication unit based on the delay time associated with a handoff request.

4. The wireless base station of claim 2, wherein the plurality of antenna units couple to the base station controller via one of a plurality of separate signal paths, and wherein each of the plurality of separate signal paths includes one or more delay units.

5. The wireless base station of claim 2, wherein the plurality of antenna units are daisy-chained to the base station controller along a common signal path, and wherein one or more delay units is inserted on the common signal path between each of the antenna units.

6. The wireless base station of claim 1, wherein the first network comprises a private network and the second network comprises a public network, and wherein the user location identification logic is further operable to decide whether the location of the mobile communication unit is within a designated handoff area by deciding whether the location of the mobile communication unit is within a designated handoff area located on a boundary between a coverage area of the private network and a coverage area of the public network.

7. The wireless base station of claim 6, wherein the private network comprises an in-building enterprise network, and wherein an exit of a building associated with the in-building network is located within the designated handoff area.

8. The wireless base station of claim 6, wherein the private network comprises an in-building enterprise network, and wherein the designated handoff area is located on a ground floor of a multi-story building associated with the in-building enterprise network.

9. A wireless communication system, comprising:

a first network;

a second network;

a first wireless base station associated with the first network and operable to communicate wirelessly with a plurality of mobile communication units;

a second wireless base station associated with the second network and operable to communicate wirelessly with the plurality of mobile communication units;

a plurality of antennas units, each antenna unit associated with a coverage area;

a plurality of delay units, each of the plurality of delay units being associated with a selected one of the plurality of antenna units, each of the plurality of delay units operable to insert an amount of delay time into a communication that is distinguishable from an amount of delay time inserted by each other delay unit; and

the plurality of mobile communication units; and

a designated handoff area, wherein the first wireless base station is operable to;

based on a delay time associated with a handoff request, determine a location of a mobile communication unit by identifying an antenna unit associated with a delay unit associated with the delay time

deny handoff requests received from mobile communication units not located within the designated handoff area.

10. The wireless communication system of claim 9, wherein the first wireless base station is operable to deny handoff requests received from mobile communication units not located within the designated handoff area by denying handoff requests received from mobile communication units that are not communicating with the first wireless base station through an antenna unit associated with a coverage area that overlaps the designated handoff area.

11. The wireless communication system of claim 9, wherein one or more of the antenna units couples to the first wireless base station through one or more delay units.

12. The wireless communication system of claim 11, wherein the first wireless base station is operable to determine the antenna unit serving the mobile communication unit based on the delay time associated with a handoff request.

13. The wireless communication system of claim 11, wherein two or more of the antenna units each couple to the first base station via one of a plurality of separate signal paths, and wherein each of the plurality of separate signal paths includes one or more delay units.

14. The wireless communication system of claim 11, wherein the plurality of antenna units are daisy-chained to the first base station along a common signal path, and wherein one or more delay units is inserted along the common signal path between each of the antenna units.

15. The wireless communication system of claim 9, wherein the first network comprises a private network and the second network comprises a public network.

16. The wireless communication system of claim 15, wherein the private network comprises an in-building enterprise network, and wherein an exit of a building associated with the in-building network is located within the designated handoff area.

17. The wireless base station of claim 15, wherein the private network comprises an in-building enterprise network, and wherein the designated handoff area is located on a ground floor of a multi-story building associated with the in-building enterprise network.

18. A method of providing communication service, comprising:

providing a plurality of delay units, each of the plurality of delay units being associated with a selected one of a plurality of antenna units, each of the plurality of delay units operable to insert an amount of delay time into a communication that is distinguishable from an amount of delay time inserted by each other delay unit; and

receiving a handoff request from a mobile communication unit;

based on the delay time associated with the handoff request, determining a location of the mobile communication unit by identifying an antenna unit associated with a delay unit associated with the delay time;

deciding whether the location of the mobile communication unit is within a designated handoff area;

executing a handoff between a first network and a second network, if the location of the mobile communication unit is within the designated handoff area; and

denying the handoff request if the location of the mobile communication unit is not within the designated handoff area.

19. The method of claim 18, wherein determining the location of the mobile communication unit comprises determining the location of the mobile communication unit based on an antenna unit from which the handoff request was received.

20. The method of claim 18, wherein the first network comprises a private network and the second network comprises a public network, and wherein deciding whether the location of the mobile communication unit is within a designated handoff area comprises deciding whether the location of the mobile communication unit is within a designated handoff area located on a boundary between a coverage area of the private network and a coverage area of the public network.

21. A system for providing mobile communication service, comprising:

means for providing a plurality of delay units, each of the plurality of delay units being associated with a selected one of a plurality of antenna units, each of the plurality of delay units operable to insert an amount of delay time into a communication that is distinguishable from an amount of delay time inserted by each other delay unit; and

means for receiving a handoff request from the mobile communication unit;

means for determining, based on the delay time associated with the handoff request, a location of the mobile communication unit by identifying an antenna unit associated with a delay unit associated with the delay time;

means for deciding whether the location of the mobile communication unit is within a designated handoff area;

means for executing a handoff between a first network and a second network, if the location of the mobile communication unit is within the designated handoff area; and

means for denying the handoff request if the location of the mobile communication unit is not within the designated handoff area.