METHOD FOR SYNCHRONIZING A TERMINAL WITH A FREQUENCY OF A RADIO-COMMUNICATIONS NETWORK, CORRESPONDING COMPUTER SOFTWARE PRODUCT, STORAGE MEANS AND TERMINAL

• US 20110292786A1
• Filed: 05/27/2011
• Published: 12/01/2011
• Est. Priority Date: 05/31/2010
• Status: Active Grant

• Current Assignee: Sierra Wireless Incorporated
• Original Assignee: Sierra Wireless Incorporated
• Inventors: Haessler, Ludovic, Fléchelle, Christophe
• Granted Patent: US 9,113,409 B2
• Time in Patent Office: Days
• US Class Current: 370/216
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 72/00 Local resource management

Abstract

A method and apparatus are provided for synchronizing a terminal with a frequency from an ordered initial sequence of frequencies of a radio-communications network. An available power spectrum associates to each frequency of the initial sequence a power value representing the power with which the frequency is received by the terminal. At least one first range of consecutive frequencies is determined within the initial sequence, having a power variation below a first predetermined threshold. The terminal attempts at least one first synchronization with a frequency of the first range. If each first synchronization fails, the terminal obtains a modified sequence by modifying the position of the frequency or frequencies of the at least one first range of the initial sequence or by eliminating the at least one first range. The terminal then attempts a second synchronization with at least one of the frequencies of the modified sequence.

Claims

1. A method for synchronizing a terminal with a frequency from among an ordered initial sequence of frequencies of a radio-communications network, the terminal having available a power spectrum associating to each frequency of the initial sequence a power value representing the power with which the frequency is received by the terminal, wherein the method comprises:

determining at least one first range of consecutive frequencies within the initial sequence, associated with a part of the power spectrum that presents a power variation below a first predetermined threshold;

attempting at least one first synchronization of the terminal with a frequency of said at least one first range;

in the event of failure of each of said at least one first synchronization, obtaining a modified sequence by modifying a position of the frequency or frequencies of said at least one first range of the initial sequence or by eliminating said at least one first range of the initial sequence; and

attempting a second synchronization of the terminal with at least one of the frequencies of the modified sequence.

2. The method according to claim 1, wherein the frequency with which said at least one first synchronization is attempted is associated with a power value above a second predetermined threshold.

3. The method according to claim 1, wherein said at least one first range possesses a bandwidth greater than a third predetermined threshold.

4. The method according to claim 1, wherein the step of attempting at least one first synchronization comprises:

determining at least one second range of consecutive frequencies within said at least one first range; and

attempting a first synchronization with each frequency of said at least one second range.

5. The method according to claim 4, wherein said at least one second range has a bandwidth greater than a fourth predetermined threshold.

6. The method according to claim 1, wherein said radio-communications network is compliant with a standard belonging to the group consisting of:

the GSM standard, the D-AMPS standard and the TETRA/TETRAPOL standard.

7. A computer-readable memory storing a computer program comprising a set of instructions executable by a computer to implement a method of synchronizing a terminal with a frequency from among an ordered initial sequence of frequencies of a radio-communications network, the terminal having available a power spectrum associating to each frequency of the initial sequence a power value representing the power with which the frequency is received by the terminal, wherein the method comprises:

determining at least one first range of consecutive frequencies within the initial sequence, associated with a part of the power spectrum that presents a power variation below a first predetermined threshold;

attempting at least one first synchronization with a frequency of said at least one first range;

in the event of failure of each of said at least one first synchronization, obtaining a modified sequence by modifying a position of the frequency or frequencies of said at least one first range of the initial sequence or by eliminating said at least one first range of the initial sequence; and

attempting a second synchronization with at least one of the frequencies of the modified sequence.

8. A terminal comprising:

means for synchronizing with a frequency from an ordered initial sequence of frequencies of a radio-communications network;

an available power spectrum which associates each frequency of the initial sequence with a power value representing the power with which the frequency is received by the terminal;

means for determining at least one first range of consecutive frequencies within the initial sequence, associated with a part of the power spectrum that presents a power variation below a first predetermined threshold;

means for attempting at least one first synchronization with a frequency of said at least one first range;

means for obtaining a modified sequence, activated in the event of failure of each of said at least one first synchronization, said modified sequence being obtained by modifying a position of the frequency or frequencies of said at least one first range of the initial sequence or by eliminating said at least one first range of the initial sequence; and

means for attempting a second synchronization with at least one of the frequencies of the modified sequence.