Method for selecting a preferable wireless communications service provider in a multi-service provider environment

• US 20040219915A1
• Filed: 05/26/2004
• Published: 11/04/2004
• Est. Priority Date: 12/12/1995
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Wireless Services Incorporated (AT&T, Inc.)
• Inventors: Raffel, Michael Allen, Lawrence, Christopher Gregory, Daly, John J., Bamburak, Michael D., Prise, Michael Edward
• Granted Patent: US 7,346,350 B2
• Time in Patent Office: Days
• US Class Current: 455/435.2
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A communication device locates a preferable wireless service provider in a multi-service provider environment using a frequency or frequency band search schedule. Initially, the communication device registers with a less preferred service provider in a first frequency. While remaining registered with the less preferred service provider, the device examines several frequencies in the order specified by the frequency search schedule. The device determines whether the last frequency used by the communication device has a more preferred service provider. If the last frequency used does not have a more preferred service provider, the device examines each of the plurality of frequencies in the predetermined order in the search schedule. The examination continues until another frequency band having a more preferred service provider is located. The communication device then registers with the more preferred service provider.

Claims

1. A method by which a communication device locates a wireless service provider in a multi-service provider environment, the method comprising:

storing a frequency band search schedule having a plurality of frequency bands in a prioritized order;

selecting a first frequency band;

performing a search of the first frequency band to determine a frequency of a strongest signal within the first frequency band;

determining if an identifying signal at the frequency of the strongest signal can be decoded;

if the identifying signal cannot be decoded, selecting a next frequency band in the prioritized order; and

if the identifying signal can be decoded, decoding the identifying signal to identify a service provider.

2. The method of claim 1, further comprising:

determining if the first frequency band is a cellular band or a personal communication services band;

wherein;

when the first frequency band is a cellular band, performing the search of the first frequency band comprises determining a frequency of a strongest signal of an analog control channel; and

when the first frequency band is a personal communications services band, performing the search of the first frequency band comprises performing a received signal strength search of the first frequency band to determine a frequency of a strongest signal within the personal communications services band.

3. The method of claim 2, wherein performing the received signal strength search further comprises:

a) dividing the first frequency band into segments;

b) selecting a first segment;

c) detecting a strongest signal within the first segment; and

d) identifying a frequency and amplitude of the strongest signal within the first segment.

4. The method of claim 3, wherein performing the received signal strength search further comprises:

comparing the identified amplitude of the strongest signal within the first segment to a threshold amplitude level; and

storing the identified frequency and amplitude of the strongest signal that exceeds the threshold amplitude level.

5. The method of claim 4, further comprising:

determining if an identifying signal at the stored frequency of the strongest signal within the first frequency segment can be decoded; and

when the identifying signal at the stored frequency of the strongest signal within the first segment cannot be decoded;

e) selecting a next segment;

f) detecting a strongest signal within the next segment;

g) identifying a frequency and amplitude of the strongest signal within the next segment;

h) comparing the identified amplitude of the strongest signal within the next segment to a threshold level;

i) storing the identified frequency and amplitude of the strongest signal, if the amplitude of the strongest signal exceeds the threshold amplitude level;

j) determining if an identifying signal at the stored frequency of the strongest signal within the next segment can be decoded; and

when the identifying signal at the stored frequency of the strongest signal within the next segment cannot be decoded, repeating steps e) through j) until an identifying signal at the stored frequency of the strongest signal within a next segment can be decoded or until the entire first frequency band has been searched.

6. The method of claim 5, wherein if it is determined that the identifying signal at the stored frequency of the strongest signal within the next segment can be decoded, decoding the identifying signal to identify a service provider.

7. The method of claim 3, wherein each segment is about 2.5 MHz wide.

8. The method of claim 3, further comprising:

a) dividing the segments into steps;

b) tuning to a first frequency in a first segment;

c) detecting a signal at the first frequency;

d) comparing an amplitude of the signal at the first frequency to a threshold amplitude level; and

e) when the amplitude of the signal at the first frequency exceeds the threshold amplitude level, storing the frequency and amplitude of the signal at the first frequency.

9. The method of claim 8, further comprising:

f) incrementing to a next frequency by a size of the step;

g) detecting a signal at the next frequency;

h) comparing an amplitude of the signal at the next frequency to a previously stored amplitude;

i) when the amplitude of the signal at the next frequency exceeds the previously stored amplitude, storing the frequency and amplitude of the signal at the next frequency as a new stored amplitude and frequency; and

repeating steps f) through i) until the entire segment has been searched.

10. The method of claim 9, further comprising:

selecting the frequency corresponding to the new stored amplitude as a frequency for decoding an identifying signal when the new stored amplitude exists, and selecting the first frequency when the new stored amplitude does not exist.

11. The method of claim 9, wherein the size of the step is about 30 kHz.

12. A wireless communication device that locates a wireless service provider in a multi-service provider environment, comprising:

a memory that stores a frequency band search schedule having a plurality of frequency bands in a prioritized order; and

a processor that selects a first frequency band, performs a search of the first frequency band to determine a frequency of a strongest signal within the first frequency band, determines if an identifying signal at the frequency of the strongest signal can be decoded, if the identifying signal cannot be decoded, selects a next frequency band in the prioritized order, and if the identifying signal can be decoded, decodes the identifying signal to identify a service provider.

13. The wireless communication device of claim 12, wherein the processor determines if the first frequency band is a cellular band or a personal communication services band, and when the band is a cellular band, determines a frequency of a strongest signal of an analog control channel, and when the band is a personal communications services band, performs a received signal strength search of the band to determine a frequency of a strongest signal within the personal communications services band.

14. A recording medium that stores a control program for use by a wireless communication device, the control program including instructions for:

storing a frequency band search schedule having a plurality of frequency bands in a prioritized order;

selecting a first frequency band;

performing a search of the first frequency band to determine a frequency of a strongest signal within the first frequency band;

determining if an identifying signal at the frequency of the strongest signal can be decoded;

if the identifying signal cannot be decoded, selecting a next frequency band in the prioritized order; and

if the identifying signal can be decoded, decoding the identifying signal to identify a service provider.

15. The recording medium of claim 14, the control program further including instructions for a control program for use by a wireless communication device, the control program including instructions for:

determining if the frequency band is cellular band or a personal communication services band;

wherein;

when the band is a cellular band, performing the search of the first frequency band comprises determining a frequency of a strongest signal of an analog control channel; and

when the band is a personal communications services band, performing the search of the first frequency band comprises performing a received signal strength search of the band to determine a frequency of a strongest signal within the personal communications services band.

16. The recording medium of claim 14, the control program further including instructions for performing the received signal strength search by:

a) dividing the first frequency band into segments;

b) selecting a first segment;

c) detecting a strongest signal within the first segment; and

d) identifying a frequency and amplitude of the strongest signal within the first segment.

17. The recording medium of claim 16, the control program further including instructions for performing the received signal strength search by:

comparing the identified amplitude of the strongest signal within the first segment to a threshold amplitude level; and

storing the identified frequency and amplitude of the strongest signal that exceeds the threshold amplitude level.

18. The recording medium of claim 17, the control program further including instructions for:

determining if an identifying signal at the stored frequency of the strongest signal within the first frequency segment can be decoded; and

when the identifying signal at the stored frequency of the strongest signal within the first segment cannot be decoded;

e) selecting a next segment;

f) detecting a strongest signal within the next segment;

g) identifying a frequency and amplitude of the strongest signal within the next segment;

h) comparing the identified amplitude of the strongest signal within the next segment to a threshold amplitude level;

i) storing the identified frequency and amplitude of the strongest signal, if the amplitude of the strongest signal exceeds the threshold amplitude level;

j) determining if an identifying signal at the stored frequency of the strongest signal within the next segment can be decoded; and

when the identifying signal at the stored frequency of the strongest signal within the next segment cannot be decoded, repeating steps e) through j) until an identifying signal at the stored frequency of the strongest signal within a next segment can be decoded, or until the entire first frequency band has been searched.

19. The recording medium of claim 18, the control program further including instructions for:

decoding the identifying signal to identify a service provider, when it is determined that the identifying signal at the stored frequency of the strongest signal within the next segment can be decoded.