Method of reselecting a cell by a mobile terminal in idle mode in a cellular telecommunication network

• US 20040136340A1
• Filed: 11/26/2003
• Published: 07/15/2004
• Est. Priority Date: 11/28/2002
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Lambert, Jean Pierre, Sanchez, Javier
• Granted Patent: US 7,430,417 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 60/04 using triggered events

Abstract

A method of reselecting a cell by a mobile terminal in idle mode in a cellular telecommunication network in which the network sends to the terminal a list containing information with regard to the UMTS cells to be identified, and in which the mobile terminal periodically performs a series of procedures of identifying the cells and a series of intersystem measurements on the identified cells. Between two successive procedures of identification, the mobile terminal performs a series of procedures of measurement whose duration is fixed so that the total duration for performing a procedure of measurement and the subsequent series of procedures of identification is less than 25 seconds.

Claims

1. A method of reselecting a cell by a mobile terminal in idle mode in a cellular telecommunication network in which the network sends to the terminal a list containing information with regard to the UMTS cells to be identified, and the terminal periodically performs a series of procedures of identifying said cells and a series of intersystem measurements on the identified cells,

wherein, between two successive procedures of identification, the terminal performs a series of procedures of measurement whose duration is fixed so that total duration for performing a procedure of measurement and the subsequent series of procedures of identification is less than 25 seconds.

2. The method according to claim 1, further comprising the steps of:

comparing the measurements performed for each cell against a predefined selection criterion, and

reselecting the UMTS cell according to a result of the comparing step.

3. The method according to claim 2, further comprising the step of performing the measurements on sliding time windows so as to obtain a mean value of said measurements.

4. The method according to claim 1, wherein the terminal performs a confirmation measurement at the end of a maximum duration of five seconds at most following the identification of a new cell.

5. The method according to claim 4, further comprising the steps of:

comparing the measurements performed for each cell against a predefined selection criterion, and

reselecting the UMTS cell according to a result of the comparing step.

6. The method according to claim 5, further comprising the step of performing the measurements on sliding time windows so as to obtain a mean value of said measurements.

7. The method according to claim 1, wherein the intersystem measurements and the procedures of identification of cells are performed with the same frequency.

8. The method according to claim 7, further comprising the steps of:

comparing the measurements performed for each cell against a predefined selection criterion, and

reselecting the UMTS cell according to a result of the comparing step.

9. The method according to claim 8, further comprising the step of performing the measurements on sliding time windows so as to obtain a mean value of said measurements.

10. The method according to claim 1, wherein the intersystem measurements are performed with a frequency that is higher than the one for the procedures of identification.

11. The method according to claim 10, further comprising the steps of:

comparing the measurements performed for each cell against a predefined selection criterion, and

reselecting the UMTS cell according to a result of the comparing step.

12. The method according to claim 11, further comprising a step that consists in performing the measurements on sliding time windows so as to obtain a mean value of said measurements.

13. A GSM-UMTS dual mode mobile terminal comprising:

means for periodically performing a series of procedures of identifying UMTS cells and a series of intersystem measurements on the identified cells;

means for allocating, every 20 seconds, a time window for identifying new UMTS cells among a plurality of UMTS cells indicated to the mobile terminal by the network, said time windows being alternately assigned to various carrier frequencies used in the cells of the network; and

means for simultaneously performing, every five seconds, measurements on the UMTS cells already identified belonging to same carrier frequency.

14. The mobile terminal according to claim 13, further comprising means for performing a confirmation measurement on each new cell identified and satisfying a predefined reselection criterion, said confirmation measurement being performed at most five seconds after the identification of that new cell.