Method and apparatus for inter-cell handover in wireless networks using multiple protocols

• US 7,469,142 B2
• Filed: 09/06/2005
• Issued: 12/23/2008
• Est. Priority Date: 04/28/2000
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sayers, Ian Leslie, Long, Paul Jan, Nelakanti, Bhavannarayana Sri Nrusimha
• Primary Examiner(s): GESESSE, TILAHUN
• Application Number:
  US11/221,237
• Publication Number:
  US 20060019664A1
• Time in Patent Office: 1,204 Days
• Field of Search: 455/442, 455/439, 455/453, 455/445, 455/432.1, 455/436, 455/437, 455/438, 455/426, 455/450, 370/338, 370/475, 370/335
• US Class Current: 455/436
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface

Abstract

A communication system formed by a private wireless network that can be used with public wireless networks using a public wireless protocol, such as GSM, and typically includes public networks, such as PSTN, ISDN and the Internet, using a wired-packet protocol, such as IP. The private network also typically includes a local area network (LAN) and the private network typically connects to the public networks using the wired-packet protocol, such as IP. The public and private wireless networks operate with the same public wireless protocol, such as GSM, and the private wireless network additionally operates with the wired-packet protocol, such as IP. In this environment, multiple wireless cells are present and inter-cell handovers employ multiple protocols including the wired-packet protocol.

Claims

1. A method for performing a handoff of a wireless mobile station from an anchor BTS to a target BTS, the method carried out in a wireless network,

wherein the wireless network is one of an interconnected plurality of wireless networks, each of said plurality of wireless networks operating with a wireless protocol for communications with mobile stations, each of said plurality of wireless networks also including a plurality of wireless cells for providing communications to said mobile stations, each of said plurality of wireless networks also including signaling, voice, and data traffic links that enable network communications with base transceiver stations;

with at least one wireless network in said plurality of wireless networks further;

providing signaling, voice, and data traffic links using a wired-packet protocol;

interconnecting at least one of the voice and data traffic links using the wired-packet protocol with at least one of the voice and data traffic links of one or more wireless networks;

interconnecting via an interworking unit, signaling traffic links using the wired-packet protocol with the signaling traffic links of one or more wireless networks;

interfacing the wireless protocol and the wired-packet protocol whereby base transceiver stations communicate with mobile stations using the wireless protocol and use the wired-packet protocol to enable handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells; and

controlling the handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells, the handover being further controlled by the steps of;

identifying the target BTS using measurement data from the mobile station;

issuing a request message to the target BTS to request that the target BTS allocate resources at the target BTS to accommodate the mobile station; and

instructing the mobile station to handoff to the target BTS.

2. A method as defined in claim 1 further comprising:

establishing a connection between the anchor BTS and the target BTS wherein the connection is used to transfer messages between the anchor BTS and the target BTS.

3. A method as defined in claim 2 further comprising:

allocating a port associated with the connection.

4. A method as defined in claim 3 wherein the port is a Real Time Protocol (RTP) port.

5. A method as defined in claim 1 further comprising:

requesting an address associated with the target BTS.

6. A method as defined in claim 5 wherein the address is an Internet Protocol (IP) address.

7. A method as defined in claim 5 wherein the address is used to address messages to the target BTS.

8. A method as defined in claim 1 further comprising:

acquiring an address associated with the target BTS.

9. A method as defined in claim 8 wherein the address is contained in a location confirm message issued by the target BTS.

10. A method as defined in claim 1 further comprising:

receiving an acknowledgment message from the target BTS wherein the acknowledgment message indicates that resources are available on the target BTS to accommodate the mobile station.

11. A method as defined in claim 1 wherein the resources at the target BTS include a port associated with a connection that is used to transfer messages associated with the handoff between the anchor BTS and the target BTS.

12. A method as defined in claim 1 wherein the resources include a radio channel.

13. A method as defined in claim 1 further comprising:

receiving a handover success indication message from the target BTS.

14. A method as defined in claim 1 further comprising:

receiving an end session message from the target BTS; and

in response to receiving the end session message, releasing resources associated with the mobile station.

15. An apparatus for performing a handoff of a wireless mobile station from an anchor base station transceiver (BTS) to a target BTS, the apparatus being in a wireless network;

wherein the wireless network is one of an interconnected plurality of wireless networks, each of said plurality of wireless networks operating with a wireless protocol for communications with mobile stations, each of said plurality of wireless networks also including a plurality of wireless cells for providing communications to said mobile stations, each of said plurality of wireless networks also including signaling, voice, and data traffic links that enable network communications with base transceiver stations;

with at least one wireless network in said plurality of wireless networks further;

providing signaling, voice, and data traffic links using a wired-packet protocol;

interconnecting at least one of the voice and data traffic links using the wired-packet protocol with at least one of the voice and data traffic links of one or more wireless networks;

interconnecting via an interworking unit, signaling traffic links using the wired-packet protocol with the signaling traffic links of one or more wireless networks;

interfacing the wireless protocol and the wired-packet protocol whereby base transceiver stations communicate with mobile stations using the wireless protocol and use the wired-packet protocol to enable handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells; and

controlling the handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells;

with the apparatus further comprising;

means for determining the target BTS using measurement data from the mobile station;

means for issuing a request message to the target BTS to request that the target BTS allocate resources at the target BTS to accommodate the mobile station; and

means for instructing the mobile station to handoff to the target BTS.

16. An anchor base station transceiver (BTS) for performing a handoff of a wireless mobile station from the BTS to a target BTS, the apparatus being in a wireless network;

wherein the wireless network is one of an interconnected plurality of wireless networks, each of said plurality of wireless networks operating with a wireless protocol for communications with mobile stations, each of said plurality of wireless networks also including a plurality of wireless cells for providing communications to said mobile stations, each of said plurality of wireless networks also including signaling, voice, and data traffic links that enable network communications with base transceiver stations;

with at least one wireless network in said plurality of wireless networks further;

providing signaling, voice, and data traffic links using a wired-packet protocol;

interconnecting at least one of the voice and data traffic links using the wired-packet protocol with at least one of the voice and data traffic links of one or more wireless networks;

interconnecting via an interworking unit, signaling traffic links using the wired-packet protocol with the signaling traffic links of one or more wireless networks;

interfacing the wireless protocol and the wired-packet protocol whereby base transceiver stations communicate with mobile stations using the wireless protocol and use the wired-packet protocol to enable handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells; and

controlling the handover of mobile stations from one of said plurality of wireless cells to another one of said plurality of wireless cells;

with the apparatus further comprising;

means for identifying the target BTS using measurement data from a mobile station;

a call control (CC) module configured to issue a request message to the target BTS to request that the target BTS allocate resources at the target BTS to accommodate the mobile station; and

a radio resource (RR) module configured to instruct the mobile station to handoff to the target BTS.

17. An anchor base station as defined in claim 16 wherein the request message contains user data associated with the mobile station.

18. An anchor base station as defined in claim 16 further comprising:

means for receiving a confirmation from the target BTS.

19. An anchor base station as defined in claim 18 further comprising:

means for receiving an end session message; and

means for releasing resources at the anchor base station that were allocated to accommodate the mobile station.