Tower discovery and failover

• US 7,403,754 B2
• Filed: 03/09/2006
• Issued: 07/22/2008
• Est. Priority Date: 12/11/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Thompson, R. Donald III, Corbea, Cosmin A.
• Primary Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US11/372,405
• Publication Number:
  US 20070060084A1
• Time in Patent Office: 866 Days
• Field of Search: 455/185.1, 455/186.1, 455/45, 455/161.1, 455/2, 455/166.1, 455/179.1, 455/3.01, 455 303- 5, 340 746- 48
• US Class Current: 455/185.1
• CPC Class Codes: H03J 1/0058 provided with channel identification means arrangements for monitoring the use made of broadcast services H04H60/31
• CPC Class Codes: H04H 20/57 for mobile receivers
• CPC Class Codes: H04H 60/41 for identifying broadcast space, i.e. broadcast channels, broadcast stations or broadcast areas
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• 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
• CPC Class Codes: H04W 84/022 One-way selective calling networks, e.g. wide area paging

Abstract

Described is a communication system including wireless client devices. In the described system, the client devices may be wrist-worn watches such as are in common use today, except that the watches are specially configured to receive transmissions from broadcast towers. A client device is associated with one or more home service regions, and is configured to receive personal messages on a home channel when in the home service region. The client device employs a self-assignment method to identify and select a home channel without the need for interaction by a user. A tower discovery method is employed to identify broadcast towers and available channels within a service region. A failover method is employed to identify a change in the broadcast system, and take appropriate action such as, for example, changing to another broadcast tower, selecting another frequency, selecting a sleep mode, as well as others.

Claims

1. A method for a client device to communicate with at least one broadcast tower within a service region, the method comprising:

during a service activation;

allocating a home frequency; and

allocating a home service region;

after the service activation;

identifying a valid broadcast channel for the client device, comprising;

initiating a frequency sweep;

selecting a station frequency during the frequency sweep;

tuning a receiver to the selected station frequency;

receiving frames over a sample-interval with the receiver;

storing the received frames over the sample-interval;

analyzing the stored frames to determine a validity status associated with the stored frames;

locking the selected station frequency when the stored frames identify a valid signal; and

selecting another station frequency when the stored frames indicate an invalid signal;

after a valid broadcast channel is identified;

extracting the assigned home frequency from the stored frames;

extracting the assigned home service region from the stored frames; and

assigning the home frequency and home service region to the client device.

2. The method of claim 1, further comprising retrieving a broadcast tower list associated with the service region from the stored frames after a valid broadcast channel is identified.

3. The method of claim 1, wherein extracting the assigned home frequency from the stored frames comprises:

applying a unique identifier associated with the client device to a code generator to identify a decryption code, and decrypting the assigned home frequency from the stored frames with the identified decryption code.

4. The method of claim 1, wherein extracting the assigned home service region from the stored frames comprises:

applying a unique identifier associated with the client device to a code generator to identify a decryption code, and decrypting the assigned home frequency from the stored frames with the identified decryption code.

5. The method of claim 1, wherein extracting the assigned home frequency from the stored frames comprises:

computing a unique code, wherein the unique code is associated with the client device; and

determining the home frequency from the unique code by;

identifying a station number as station number=N modulo n, wherein “

N”

corresponds to at least a portion of the unique code, and “

n”

corresponds to the number of stations in the service region.

6. The method of claim 1, further comprising assigning a broadcast tower to the client device by:

retrieving a broadcast tower list associated with the service region from the stored frames after a valid broadcast channel is identified;

computing a unique code, wherein the unique code is associated with the client device; and

identifying the assigned broadcast tower for the client device as an offset relative to the retrieved broadcast tower list, wherein the offset is determined by offset=N modulo n, wherein “

N”

corresponds to at least a portion of the computed unique code, and “

n”

corresponds to the number of stations in the service region, wherein N corresponds to the number of broadcast towers that are available in the service region.

7. The method of claim 1, wherein tuning the receiver to the selected station frequency, further comprises tuning the receiver for reception according to at least one of a frequency modulated (FM) transmission, and a sub-carrier based frequency modulated transmission.

8. The method of claim 1, wherein analyzing the stored frames to determine the validity status associated with the stored frames further comprises:

identifying a data sync pattern in the frame such that a correlation of the data sync pattern by the client device indicates a valid signal reception by the client device.

9. The method of claim 8, wherein the data sync pattern is encoded with a unique identifier that is associated with the client device.

10. The method of claim 8, wherein the data sync pattern is encoded in a distributed manner over several segments of the transmission.

11. The method of claim 1, the received frames comprising:

a frame header and a message payload.

12. The method of claim 11, wherein information is encoded in the frame header, wherein the encoded information includes at least one of a station list, a broadcast tower list, and a control message.

13. The method of claim 11, wherein the frame header is encoded control information to identify at least one of:

a broadcast condition associated with the service region for the broadcast tower, a change in available channels associated with the service region for the broadcast tower, an assignment of a particular channel for the client device, an assignment of another particular channel for all client devices, and a change counter that is arranged to indicate when a change has taken place in the system.

14. The method of claim 1, further comprising:

receiving a transmission from a valid broadcast channel;

computing a unique code, wherein the unique code is associated with the client device; and

decoding a personal message for the client device from the stored frames using the computed unique code.

15. A client device that is arranged in communication with at least one broadcast tower, the client device comprising:

a means for scheduling reception on the client device;

a means for tuning a receiver in the client device to a selected station;

a means for receiving a transmission frame with the client device when scheduled for reception, wherein the transmission frame includes a frame header and a message payload;

a means for storing the received transmission frame;

a means for analyzing that is arranged to determine a validity status associated with the stored transmission frame;

a means for changing the selected station when the validity status is determined as invalid;

a means for extracting a station list from the frame header when the validity status is determined as valid;

a means for selecting a home station from the station list, wherein the home station is automatically assigned by the client device utilizing a unique code that is associated with the client device; and

a means for changing the default for the selected station to the home station; and

a means for decoding a personal message from the stored transmission frame, wherein the stored transmission frame is encoded with an encryption key that is determined from the unique code that is identified with the client device.

16. The method of claim 15, further comprising a means for automatically assigning a home broadcast tower to the client device by extracting information from the frame header utilizing the unique code that is associated with the client device.