Scanning and decoding methods and apparatus for mobile communication devices

• US 7,689,216 B2
• Filed: 11/16/2005
• Issued: 03/30/2010
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Wandel, Matthias
• Primary Examiner(s): Pérez-Gutiérrez; Rafael
• Assistant Examiner(s): Patel; Nimesh
• Application Number:
  US11/280,686
• Publication Number:
  US 20070111740A1
• Time in Patent Office: 1,595 Days
• Field of Search: 455/434, 455/160.1, 455/154.2, 455/161.1, 455/513, 370/331, 370/230, 370/231, 370/233, 370/234, 370/235, 370/237, 370/232, 370/360, 370/385.2, 709/240, 709/235, 710/29
• US Class Current: 455/434
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

In one illustrative scanning and decoding method, a signal strength level of an RF signal on an RF channel is measured for a plurality of RF channels of an RF band. The act of measuring a signal strength level is repeated at least one time to obtain at least one other signal strength level of the RF signal. Subsequently, an averaging function is completed with use of the signal strength level and the at least one other signal strength level for identifying an averaged signal strength level of the RF signal. At least one optimal RF signal is then identified based on the averaged signal strength levels of the RF signals on the RF channels. In between the repeated acts of measuring signal strength levels of the RF signals, and prior to identifying the averaged signal strength levels, control information is decoded on at least one of the RF channels and stored in memory. A wireless communication network is selected for communication with use of the control information stored in the memory which corresponds to one of the at least one optimal RF signal. In this manner, the mobile station expeditiously obtains the control information for network selection or other purposes prior to completing the averaging of the signal strength levels.

Claims

1. A network selection method comprising:

performing the following acts for each broadcast control channel of a plurality of broadcast control channels defined in a wireless communication system which includes a plurality of wireless communication networks;

measuring, on the broadcast control channel, a signal strength level of a radio frequency (RF) signal of a wireless communication network;

repeating the act of measuring on the broadcast control channel at least one time so that at least one other signal strength level of the RF signal on the broadcast control channel is identified;

completing an averaging function with the signal strength level and the at least one other signal strength level for calculating an averaged signal strength level of the RF signal on the broadcast control channel, the averaged signal strength level being an average of the signal strength level and the at least one other signal strength level;

prior to the completion of the averaging function for the calculating of the averaged signal strength level of, and in between or during the repeated acts of measuring the signal strength levels of the RF signal on the broadcast control channel;

decoding control information on the broadcast control channel and storing the control information in memory, the control information including a network identification which uniquely identifies the wireless communication network;

after the performing of the acts for each said broadcast control channel, performing the further acts of;

identifying at least one optimal RF signal from the averaged signal strength levels that were calculated from the completion of the averaging function for each said RF signal on each said broadcast control channel; and

selecting and registering with one of the wireless communication networks for communication service with use of the control information that was decoded and stored in the memory prior to the completion of the averaging function, the selected wireless communication network being associated with the at least one optimal RF signal identified from the averaged signal strength levels.

2. The method of claim 1, further comprising:

wherein the averaging function is performed in accordance with Global Systems for Mobile communications (GSM) standards and the control information comprises control information of a broadcast control channel (BCCH).

3. The method of claim 1, further comprising:

reading the control information from the memory for use in selecting the wireless communication network for communication.

4. The method of claim 1, further comprising:

prior to the completion of the averaging function for the calculating of the averaged signal strength level of the RF signal on each said broadcast control channel, identifying at least one optimal RF signal from the signal strength levels measured on each said broadcast control channel; and

wherein the act of decoding comprises decoding the control information on the broadcast control channel if the broadcast control channel has the at least one optimal RF signal.

5. The method of claim 1, wherein the acts of measuring the signal strength level of the RF signal on each said broadcast control channel is performed based on the same predetermined bandwidth for each broadcast control channel.

6. The method of claim 1, further comprising:

wherein in a first repetition of signal strength measurements taken for the broadcast control channels of the RF band, the method further comprises;

identifying a first signal strength level of a first 1W signal on a first broadcast control channel;

identifying that the first RF signal is an optimal 1W signal based at least on the first signal strength level;

decoding first control information on the first broadcast control channel and storing the first control information in memory based on identifying that the first RF signal is an optimal RF signal;

wherein in a subsequent repetition of signal strength measurements taken for the broadcast control channels of the RF band, the method further comprises;

identifying a second signal strength level of a second RF signal on a second broadcast control channel which is different from the first broadcast control channel;

identifying that the second RF signal is an optimal RF signal based at least on the second signal strength level; and

decoding second control information on the second broadcast control channel and storing the second control information in memory based on identifying that the second RF signal is an optimal RF signal.

7. The method of claim 1, wherein the network identification comprises a mobile network code (MNC) and a mobile country code (MCC) pair.

8. The method of claim 1, wherein the method is performed by a mobile station, the wireless communication network comprises a Global Systems for Mobile communications (GSM) network and the act of identifying is performed five times for each said RF signal on each said broadcast control channel over a time period of about five seconds.

9. A communication device, comprising;

a radio frequency (RF) transceiver;

one or more processors coupled to the RF transceiver;

the one or more processors being adapted to perform the following acts for each broadcast control channel of a plurality of broadcast control channels defined in a wireless communication system which includes a plurality of wireless communication networks;

measure, on the broadcast control channel, a signal strength level of an RF signal of a wireless communication network;

repeat the act of measuring on the broadcast control channel at least one time so that at least one other signal strength level of the RF signal on the broadcast control channel is identified;

complete an averaging function with the signal strength level and the at least one other signal strength level for calculating an averaged signal strength level of the RF signal on the broadcast control channel, the averaged signal strength level being an average of the signal strength level and the at least one other signal strength level; and

prior to the completion of the averaging function for the calculating of the averaged signal strength level, and in between or during the repeated acts of measuring the signal strength levels of the RF signal on the broadcast control channel;

decode control

information on the broadcast control channel and store the control information in memory, the control information including a network identification which uniquely identifies the wireless communication network;

the one or more processors being further adapted to, after the performing of the acts for each said broadcast control channel, perform the following further acts;

identify at least one optimal RF signal from the averaged signal strength levels that were calculated from the completion of the averaging function for each said RF signal on each said broadcast control channel; and

select and register with one of the wireless communication networks for communication service with use of the control information that was decoded and stored in the memory prior to the completion of the averaging function, the selected wireless communication network being associated with the at least one optimal RF signal identified from the averaged signal strength levels,

10. The communication device of claim 9, wherein the scanning is based on Global Systems for Mobile communications (GSM) standards and each said broadcast control channel is a broadcast control channel (BCCH).

11. The communication device of claim 9, wherein the one or more processors are further adapted to:

read the control information from the memory for use in selecting the wireless communication network for communication.

12. The communication device of claim 9, wherein the one or more processors are further adapted to, prior to the completion of the averaging function for the calculating of the averaged signal strength level of the RF signal on each said broadcast control channel, identify at least one optimal RF signal from the signal strength levels measured on each said broadcast control channel, and wherein the one or more processors are further adapted to decode by decoding the control information on the broadcast control channel if the broadcast control channel has the at least one optimal RF signal.

13. The communication device of claim 9, wherein the one or more processors are further operative to decode the control information by decoding control information on two or more of the broadcast control channels of the RF band simultaneously and storing the control information in memory.

14. The communication device of claim 9, wherein the one or more processors are further adapted to decode by assigning two or more contexts for decoding control information on two or more of the broadcast control channels of the RF band simultaneously.

15. The communication device of claim 9, further comprising:

wherein the one or more processors are further adapted to, in a first repetition of signal strength measurements taken for the broadcast control channels of the RF band;

identify a first signal strength level of a first RF signal on a first broadcast control channel;

identify that the first RF signal is an optimal RF signal based at least on the first signal strength level;

decode first control information on the first broadcast control channel and storing the first control information in memory based on identifying that the first RF signal is an optimal RF signal;

wherein the one or more processors are further adapted to, in a subsequent repetition of signal strength measurements taken for the broadcast control channels of the RF band;

identify a second signal strength level of a second RF signal on a second broadcast control channel which is different from the first broadcast control channel;

identify that the second RF signal is an optimal RF signal based at least on the second signal strength level; and

decode second control information on the second broadcast control channel and storing the second control information in memory based on identifying that the second RF signal is an optimal RF signal.

16. A computer program product, comprising:

a storage medium;

computer program instructions stored in the storage medium;

the computer program instructions being executable by one or more processors for performing a network selection method by;

performing the following acts for each broadcast control channel of a plurality of broadcast control channels defined in a wireless communication system which includes a plurality of wireless communication networks;

measuring, on the broadcast control channel, a signal strength level of a radio frequency (RF) signal of a wireless communication network;

repeating the act of measuring on the broadcast control channel at least one time so that at least one other signal strength level of the RF signal on the broadcast control channel is identified;

completing an averaging function with the signal strength level and the at least one other signal strength level for calculating an averaged signal strength level for the RF signal on the broadcast control channel, the averaged signal strength level being an average of the signal strength level and the at least one other signal strength level;

prior to the completion of the averaging function for the calculating of the averaged signal strength level, and in between or during the repeated acts of measuring the signal strength levels of the RF signal on the broadcast control channel;

decoding control information on the broadcast control channel and storing the control information in memory, the control information including a network identification which uniquely identifies the wireless communication network;

after the performing of the acts for each said broadcast control channel, performing the further acts of;

identifying at least one optimal RF signal from the averaged signal strength levels that were calculated from the completion of the averaging function for each said RF signal on each said broadcast control channel; and

selecting and registering with one of the wireless communication networks for communication service with use of the control information that was decoded and stored in the memory prior to the completion of the averaging function, the selected wireless communication network being associated with the at least one optimal RF signal identified from the averaged signal strength levels.

17. The computer program product of claim 16, wherein the scanning is based on Global Systems for Mobile communications (GSM) standards and the each said broadcast control channel is a broadcast control channel (BCCH).

18. The computer program product of claim 16, wherein the computer program instructions are further executable for:

reading the control information from the memory for selecting the wireless communication network for communication.

19. The computer program product of claim 16, wherein the computer program instructions are further executable for:

prior to the completion of the averaging function for the calculating of the averaged signal strength level of the RF signal on each said broadcast control channel, identifying at least one optimal RF signal from the signal strength levels measured on each said broadcast control channel; and

decoding the control information on the broadcast control channel if the broadcast control channel has the at least one optimal RF signal.

20. The computer program product of claim 16, wherein the computer program instructions are further executable for decoding by decoding control information on two or more of the broadcast control channels of the RF band simultaneously and storing the control information in memory.

21. The computer program product of claim 16, further comprising:

wherein the computer instructions are further executable for, in a first repetition of signal strength measurements taken for the broadcast control channels of the RF band;

identifying a first signal strength level of a first RF signal on a first broadcast control channel;

identifying that the first RF signal is an optimal RF signal based at least on the first signal strength level;

decoding first control information on the first broadcast control channel and storing the first control information in memory based on identifying that the first RF signal is an optimal RF signal;

wherein the computer instructions are further executable for, in a subsequent repetition of signal strength measurements taken for the broadcast control channels of the RF band;

identifying a second signal strength level of a second RF signal on a second broadcast control channel which is different from the first broadcast control channel;

identifying that the second RF signal is an optimal RF signal based at least on the second signal strength level; and

decoding second control information on the second broadcast control channel and storing the second control information in memory based on identifying that the second RF signal is an optimal RF signal.