WO2009096769A2

WO2009096769A2 - A method and system for handoff control in a wireless communication network

Info

Publication number: WO2009096769A2
Application number: PCT/MY2009/000018
Authority: WO
Inventors: Gopakumar Kurup; Shariq Haseeb; Mazlan Abbas
Original assignee: Mimos Berhad
Priority date: 2008-01-28
Filing date: 2009-01-16
Publication date: 2009-08-06
Also published as: WO2009096769A3; MY164506A

Abstract

The present invention provides a method and system for handoff control in a wireless communication network. In an embodiment, a method for handoff control in an IP based wireless communication network, comprising (i) monitoring and obtaining movement information of a moving mobile node (ii) predicting the next point of network attachment for the client mobile node, and (iii) performing the handoff operation before the mobile node moves to a new location corresponding to next point of network attachment, wherein the interruption time during the handoff is substantially minimum.

Description

A METHOD AND SYSTEM FOR HANDOFF CONTROL IN A WIRELESS COMMUNICATION NETWORK

FIELD OF INVENTION

This invention relates generally to methods and systems for communication in wireless networks, and more particularly to, a method and system for handoff control in an IP based wireless network such as, a cellular network and a digital broadcasting network.

BACKGROUND OF THE INVENTION

Wireless data communication devices, such as wireless modems, PDAs, notebooks, etc., are becoming more and more popular as prices continue to drop and data rates to rise. There are distinct approaches for enabling mobile wireless communications of packets of data. Here it will be understood that the term "mobile" has the classic meaning of being movable or capable of moving readily.

A cellular telephone network provides radio communication to and from mobile phones over a large geographical area. Cellular networks generally consist of a plurality of adjoining geographic regions, subdivided into cells. A portion of a prior art cellular telephone network and the problem with the conventional Mobile IPv6 implementation is depicted in FIG. 1 and FIG. 2. As shown in FIG. 1, when the Mobile Node (Alice) changes the point of network attachment from one wireless coverage to another, it has to follow steps 1 to 7 for performing a successful handoff. Steps 2 to 6 are responsible for majority of the delays (as shown in FIG. 2) observed by the applications that depend on Mobile IPv6. During steps 2 to 6, the Mobile Node is unable to communicate with its corresponding (destination) node and hence results in an interruption. Depending on the Mobile IPv6 implementation, this interruption period usually lasts between 2 to 10 seconds. A known method of handoff control is disclosed in US Patent Publication No. 20070153794 titled "Method and Apparatus for Transferring a Communication Session". Accordingly, mobile IPv6 is implemented much similar to the standard (RFC 3775) using a "Home Agent" that helps in the handoff registration. However, the disclosed method and system does not result in speeding up of the handoff operation.

Another known method of handoff control is disclosed in US Patent Publication No. 20070147320 entitled "Access Router Selection Method" and US Patent Publication No. 20050232188 titled "QoS Oriented Handover Method for Mobile IPv6 in MPLS network". Accordingly, the publications disclose router selection method depending on the speed and capacity of mobile node and maintenance of QoS during handoff process.

However, the above known methods do not provide for a method and system for handoff control wherein the handoff process is carried out with (i) minimum delay and faster speed (ii) high reliability of handoff control and (iii) improved quality of signal and service and thereby reduced number of dropped calls.

SUMMARY OF INVENTION

These as well as other novel advantages, details, embodiments, features and objects of the present invention will be apparent to those skilled in the art from the following detailed description of the preferred embodiment of the invention, the attached claims, and the accompanying drawings.

In an embodiment, a system for handoff control in a wireless communication network, comprises a decision engine for acquiring information on at least one of signal strength and an SSID periodically from one or more routers in the neighborhood of a moving mobile node and information on at least one of signal strength and an SSID periodically from the moving mobile node. A home agent is provided for performing a handoff registration in communication with the decision engine, wherein based on the acquired information, the decision engine performs the handoff operation on behalf of the moving mobile node before the mobile node reaches a new location in the network.

In another embodiment, a method for handoff control in a wireless communication network, comprises (i) acquiring information on at least one of signal strength and an SSID periodically from one or more routers in the neighborhood of a moving mobile node (ii) acquiring information on at least one of signal strength and an SSID periodically from the moving mobile node; and (iii) determining the handoff parameters for the moving mobile node based on the acquired information and thereby performing the handoff on behalf of the mobile node before the mobile node reaches a new location in the network.

In yet another embodiment, a method for handoff control in a wireless communication network, comprises the steps of (i) monitoring and obtaining movement information of a moving mobile node (ii) predicting the next point of network attachment for the mobile node, and (iii) performing the handoff operation before the mobile node moves to a new location corresponding to next point of network attachment, wherein the interruption time during the handoff is substantially minimum.

BRIEF DESCRIPTION OF DRAWINGS

Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

Figure 1 shows a schematic diagram illustrating a conventional system for handoff control in a wireless communication network Figure 2 shows a message flow diagram illustrating a conventional method of handoff control in a wireless communication network.

Figure 3 shows a schematic diagram illustrating a system for handoff control in a wireless communication network according to an embodiment of this invention.

Figure 4 shows a message flow diagram illustrating a method of handoff control in a wireless communication network according to an embodiment of this invention.

Figure 5 shows a flow chart of a method of handoff control in a wireless communication network according to an embodiment of this invention.

DETAILED DESCRIPTION OF PREFERRED INVENTION

Various embodiments of this invention provide a method and system for handoff control in a wireless communication network using an IPv6 network device. However, the embodiments are not limited and may be used in connection with IPv4 network devices and telecommunication and digital broadcasting companies providing IP- telephony and IP TV services.

FIG. 3 shows a system for handoff control in a wireless communication network, wherein, in an illustration, the network comprises a mobile node 10 (referred to as "Alice" in the accompanying drawings) intended to move from the area under one Internet Service Provider ISP 1 to an area under another Internet Service Provider ISP 4. The mobile node 10 is currently attached to a router 12 provided in the area covered under the Internet Service Provider ISP 1. A router 40 is configured in the area covered under the Internet Service Provider ISP 4. Routers 20, 30 are configured in the areas covered under Internet Service Providers ISP 3 and ISP 4. The areas covered under Internet Service Providers ISP 2, ISP 3 and ISP 4 are located adjacent to area covered under Internet Service Provider ISP 1. A decision engine 14 and a home agent 16 are provided in the network.

In an example shown in FIG. 3, the decision engine 14 and the home agent 16 are coupled to the router 12 within the same network. The decision engine 14 is in communication with the home agent 16 for handoff registration.

FIG. 4 and FIG. 5 show a handoff control method according to an embodiment of this invention. Accordingly, the decision engine 14 requests information on at least one of signal strength and an SSID periodically from the routers 20, 30 and 40. As a response to the request, the routers 20, 30 and 40 return the Wireless Access names and the address they are advertising. The decision engine 14 keeps in its record, the received SSID information in a cache (not shown). The decision engine 14 also requests information on at least one of signal strength and an SSID periodically from the moving mobile node 10. Accordingly, the decision engine 14 receives information on current connected SSID, IPv6 and a scan of the surrounding access points. In an example, the request is made at an interval of about 10 seconds.

In an embodiment, the summary of the information acquired by the decision engine 14 is as follows:

(i) current SSID for the moving mobile node;

(ii) signal strength of the current SSID;

(iii) neighboring SSID, and

(iv) signal strength of the neighboring SSIDs.

In an embodiment, as the mobile node 10 moves, the mobile node 10 keeps on communicating with the decision engine 14. It should be noted that the as the mobile node 10 moves away from the current SSID and towards the neighboring SSDD, the signal strength of the of the current SSID will tend to decrease. The signal strength of the neighboring SSID towards which the mobile node 10 is moving will tend to increase. Using this variation in signal strength of the SSIDs, the decision engine 14 concludes that the mobile node is going to move and thereafter determines the handoff parameters.

In an embodiment, the handoff parameters include the following: (v) how fast the mobile node is moving (vi) towards which SSID the mobile node 10 is moving

(vii) approximate time at which the mobile node 10 will reach the new location, and

(viii) what will be the future IPv6 address of the mobile node 10.

In an embodiment, the decision engine 14 informs the new address of the mobile node 14 to the home agent 16. The home agent 16 acknowledges the communication from the decision engine 14. The decision engine 14 thereby performs the handoff operation even before the mobile node 10 reaches the new location i.e. the next point of network attachment, as the decision engine 14 knows the prefix advertised by the next Internet Service Provider.

It, it should be noted that the decision engine 14 performs monitoring and obtaining of movement information of the moving mobile node 10. The next point of network attachment is predicted for the client mobile node. The handoff operation is performed before the mobile node 10 moves to a new location corresponding to next point of network attachment. Thus according to the embodiments of this invention described above, the interruption time during the handoff operation is substantially minimum. For example, the interruption time is about less than 400 milliseconds. Thus, various specific embodiments of this invention provide a method and system for handoff control in a wireless communication network. The foregoing description of the invention has been described for purposes of clarity and understanding. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the appended claims.

Claims

1. A system for handoff control in a wireless communication network, comprises: a decision engine for acquiring:

(ix) information on at least one of signal strength and an SSID periodically from one or more routers in the neighborhood of a moving mobile node; and

(x) information on at least one of signal strength and an SSDD periodically from the moving mobile node; and a home agent for performing a handoff registration in communication with the decision engine, wherein based on the acquired information, the decision engine is configured to perform the handoff operation on behalf of the moving mobile node before the mobile node reaches a new location in the network.

2. A system as in claim 1, wherein the decision engine is further configured to analyze the acquired information for determining one or more handoff parameters for performing the handoff operation.

3. A system as in claim 1, wherein the interruption during the handoff is about 400 milliseconds.

4. A system as in claim 1, wherein handoff parameter comprises at least the speed of the mobile node.

5. A system as in claim 1, wherein handoff parameter comprises at least the SSID towards which the mobile node is moving, indicative time

6. A system as in claim 1, wherein handoff parameter comprises at least the indicative time at which the mobile node will reach the new location.

7. A system as in claim 1, wherein handoff parameter comprises at least the future IPv6 address of the mobile node.

8. A method for handoff control in a wireless communication network, comprises the actions of: acquiring information on at least one of signal strength and an SSID periodically from one or more routers in the neighborhood of a moving mobile node; acquiring information on at least one of signal strength and an SSID periodically from the moving mobile node; and determining the handoff parameters for the moving mobile node based on the acquired information and thereby performing the handoff on behalf of the mobile node before the mobile node reaches a new location in the network.

9. A method of handoff control as in claim 8, further comprising acquiring information from the neighboring routers and moving mobile node periodically for an interval of about 10 seconds.

10. A method of handoff control as in claim 9, further comprising storing the acquired information in a cache.

11. A method as in claim 8, wherein the handoff parameters include at least the speed at which the mobile node is moving.

12. A method as in claim 8, wherein the handoff parameters include at least the SSID towards which the mobile node is moving.

13. A method as in claim 8, wherein the handoff parameters include at least an indicative time at which the mobile will reach the new location.

14. A method as in claim 8, wherein the handoff parameters include at least a future IPv6 address of the mobile node.

15. A method for handoff control in a wireless communication network, comprises the actions of:

(xi) monitoring and obtaining movement information of a moving mobile node;

(xii) predicting the next point of network attachment for the mobile node; and

(xiii) performing the handoff operation before the mobile node moves to a new location corresponding to next point of network attachment, wherein the interruption time during the handoff is substantially minimum.