Method and equipment for supporting mobility in a telecommunication system

• US 20010024953A1
• Filed: 02/20/2001
• Published: 09/27/2001
• Est. Priority Date: 02/24/2000
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Balogh, Peter
• Granted Patent: US 6,870,822 B2
• Time in Patent Office: Days
• US Class Current: 455/432.1
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method for supporting mobility in a wireless telecommunication system which comprises at least one terminal, an access point currently serving the terminal and a plurality of other access points. The access points may be grouped into networks and the terminal is arranged to collect information about available access points. The network names of the available access points are checked by the terminal. The first access point with the best connection attributes of the available access points with the same network name as the currently serving access point is selected. The second access point with the best connection attributes of the available access points with a different network name than the currently serving access point is also selected. One or more connection attributes of the first access point and the second access point are compared. The connection to the second access point is established if the differences between the compared connection attributes fulfil pre-determined conditions.

Claims

1. A method for supporting mobility in a wireless telecommunication system, comprising at least one terminal, an access point currently serving the terminal and a plurality of other access points, wherein the access points may be grouped into networks and the terminal is arranged to collect information about available access points, characterized by

checking the network names of the available access points,

selecting a first access point with the best connection attributes of the available access points with the same network name as the currently serving access point,

selecting a second access point with the best connection attributes of the available access points with a different network name than the currently serving access point,

comparing one or more connection attributes of the first access point and the second access point, and

establishing a connection to the second access point if the differences between said compared connection attributes fulfil pre-determined conditions.

2. A method according to

claim 1

, characterized by

informing a user of the terminal if the differences between said compared connection attributes fulfil the pre-determined conditions, and

establishing a connection to the second access point if the user allows the connection.

3. A method according to any one of the preceding claims, characterized by

establishing a connection to the first access point if the first access point is not the currently serving access point and at least one of the differences between said compared connection attributes does not fulfil the pre-determined conditions.

4. A method according to any one of the preceding claims, characterized by

determining the connection attributes based at least on the signal levels of available access points,

selecting the first and the second access point having the highest signal levels,

comparing the signal levels of the first and the second access point, and

establishing a connection to the second access point if the difference between signal levels of the first and the second access point is above a pre-determined signal level limit.

5. A method according to any one of the preceding claims, characterized by

storing information sets identifying networks by network names in the terminal,

comparing the network names of available access points to the network names stored in the information sets, and

dropping access points with network names not described in any of the stored information sets.

6. A method according to

claim 5

, characterized in that

the stored information sets describe settings needed to access networks and their resources, and

the connection to the second access point is established using the settings described in the stored information sets.

7. A method according to any one of the preceding claims, characterized by

collecting information about available access points, selecting the first and the second access point and comparing the connection attributes periodically.

8. A method according to any one of the preceding claims, characterized in that

the networks are sub-networks of logical WLAN networks.

9. A terminal comprising a transceiver for communicating with an access point and collecting means for collecting information about available access points, characterized in that the terminal further comprises

checking means for checking the network names of the available access points,

selection means for selecting a first access point with the best connection attributes of the available access points with the same network name as the currently serving access point and for selecting a second access point with the best connection attributes of the available access points with a different network name than the currently serving access point,

comparison means for comparing one or more connection attributes of the first access point and the second access point, and

access means for establishing a connection to the second access point if the differences between said compared connection attributes fulfil pre-determined conditions.

10. A terminal according to

claim 9

, characterized in that

the terminal comprises user interface means for informing a user of the terminal if the differences between said compared connection attributes fulfil the pre-determined conditions, and

the access means are arranged to establish a connection to the second access point if the user allows the connection.

11. A terminal according to

claim 9

or

10

, characterized in that

access means are arranged to establish a connection to the first access point if the first access point is not the currently serving access point and at least one of the differences between said compared connection attributes does not fulfil the pre-determined conditions.

12. A terminal according to any one of the claims 9 - 11, characterized in that

different connection attributes are weighted differently.

13. A terminal according to any one of the claims 9 - 12, characterized in that

the terminal comprises memory means for storing information sets identifying networks by network names and describing settings needed to access networks and their resources,

the checking means are arranged to compare the network names of available access points to the network names stored in the information sets,

the checking means are arranged to drop access points with network names not described in any of the stored information sets, and

the access means are arranged to establish connection to the second access point using the settings described in the stored information sets.

14. A terminal according to any one of the claims 9 - 13 characterized in that

the connection attributes are determined at least based on the signal levels of the available access points,

selection means are arranged to select the first and the second access point having the highest signal levels,

the comparison means are arranged to compare the signal levels of the first and the second access point, and

access means are arranged to establish a connection to the second access point if the difference between the signal levels of the first and the second access point is above a pre-determined signal level limit.

15. A terminal according to any one of the claims 9 - 14, characterized in that

the terminal is a mobile terminal and is arranged to access wireless local area networks (WLANs).