Method for tracking users in a communication network

• US 7,480,508 B2
• Filed: 03/01/2007
• Issued: 01/20/2009
• Est. Priority Date: 08/19/2003
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Das, Arnab, Kang, Joseph H., Balachandran, Krishna, Dolan, Michael F., Budka, Kenneth C.
• Primary Examiner(s): Afshar, Kamran
• Application Number:
  US11/712,396
• Publication Number:
  US 20070149217A1
• Time in Patent Office: 691 Days
• Field of Search: 4554321-4323, 455/433, 4554351-4353, 455436-444, 455/448, 455/453, 4554561-457, 455524-525, 370331-335, 370/338, 370/348
• US Class Current: 455/435.1
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 60/04 using triggered events

Abstract

In a method of tracking a user in a communication network supporting a broadcast-multicast service, the network classifies groups of users into tracking areas. Movement of a user may be tracked as the user crosses a boundary between two tracking areas in the network. The method may enable a balance to be achieved between use of uplink overhead and the level or granularity of tracking desired, so as to conserve radio resources.

Claims

1. In a network supporting a broadcast-multicast service and serving a plurality of sectors, a method by which a mobile user determines a change in tracking area, comprising:

receiving, by the mobile user, mapping data classifying groups of sectors into a plurality of tracking areas, each sector having one or more groups of mobile users, the mapping data associates a given sector identifier for each sector to one of the plurality of tracking areas to create associations between each sector and tracking area that are known to each mobile user of the one or more groups;

receiving, by the mobile user, at least two pilot signals from at least two of the sectors;

if a tracking area update enabled indicator for a current sector that has not been dropped is enabled and a timer interval has expired, comparing, by the mobile user, each of the at least two pilot signals to a threshold based on an adding criteria; and

determining, by the mobile user, a change in tracking area from a previous transmission of a tracking area registration based on the comparing and the mapping data.

2. The method of claim 1, further comprising:

determining the mapping data based on one or more of pilot PN offset detection, primary scrambling code detection and explicit signaling from the network.

3. In a network supporting a broadcast-multicast service and serving a plurality of sectors, groups of sectors further classified by the network into a plurality of tracking areas, each sector having one or more groups of mobile users, a method by which one of the mobile users indicates a tracking area change to the network, comprising:

each sector transmitting a list of neighbor sectors to each user in the sector, the list including an indicator for each neighbor sector, the indicator including a bit indicating whether each neighbor sector is within a same tracking area as the transmitting sector;

the one of the mobile users

if a tracking area update enabled indicator for a current sector is enabled and a timer interval has expired, comparing a pilot signal strength and indicator bit of each of the neighbor sectors on the list that have not been dropped to determine changes in tracking area from a previous transmission of a tracking area registration; and

transmitting a registration message indicting a change in tracking area to the network, based on the comparing.

4. In a network supporting a broadcast-multicast service and serving a plurality of sectors, groups of sectors further classified by the network into a plurality of tracking areas, each sector having one or more groups of mobile users, a method by which one of the mobile users determines a tracking area, comprising:

classifying neighboring sectors belonging to the same tracking area into an ordered neighbor sector list;

each sector transmitting a bitmap of sector identifiers to indicate whether a tracking area of a current sector is different from the tracking area of a previous sector in the neighbor sector list, so that each of the mobile users knows each sector identifier and each neighboring sector belonging to a different tracking area of the previous sector;

if a tracking area update enabled indicator for a current sector is enabled and a timer interval has expired, the one of the mobile users comparing a pilot signal strength of the neighbor sectors and indicator bits of the bitmap corresponding to the neighbor sectors to determine changes in tracking area from a previous transmission of a tracking area registration; and

transmitting a registration message indicting a change in tracking area to the network, based on the comparing.

5. The method of claim 4, further comprising:

the network assigning indicator bits to represent neighbor sectors of the ordered candidate neighbor list; and

the accessing the bitmap step further comprising the one of the mobile users looking up an indicator bit for a particular sector to determine if the sector'"'"'s tracking area matches that of the one of the mobile users.