Tower discovery and failover

• US 20040116068A1
• Filed: 12/11/2002
• Published: 06/17/2004
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Thompson, R. Donald III, Corbea, Cosmin A.
• Granted Patent: US 7,043,214 B2
• Time in Patent Office: Days
• US Class Current: 455/3.01
• 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 maintain communications with a broadcast tower within a service region, comprising:

initializing the client device to a receiver channel, further comprising;

initiating a frequency sweep;

selecting a frequency during the frequency sweep;

tuning a receiver to the selected frequency;

receiving frames over a sample-interval with the receiver;

storing the received frames over the sample-interval;

analyzing the received frames;

locking the selected frequency when the received frames identify a valid signal;

selecting another frequency when the received frames indicate an invalid signal;

retrieving a station list when the selected frequency is locked;

selecting a home station from the station list; and

receiving messages from the receiver, wherein the receiver is tuned to the locked frequency, wherein the received messages are associated with the home station.

2. The method of claim 1, wherein the frequency sweep corresponds to one of a linear sweep, a logarithmic sweep, a sweep of frequencies in predetermined steps, and selecting frequencies from a table of predetermined frequencies.

3. The method of claim 1, wherein the frequency sweep ranges over the FM broadcast spectrum.

4. The method of claim 1, wherein the frequency sweep ranges between 88 MHz and 107 MHz in 100 kHz increments.

5. The method of claim 1, wherein analyzing the received frames comprises correlating the stored frames, and identifying the valid signal when the correlation identifies frames that are assigned to a service region that matches the client device home service region.

6. The method of claim 1, further comprising assigning the current service region as the client home service region when the client home service region was previously unassigned, wherein the current service region is identified from the received frames.

7. The method of claim 1, further comprising:

manually assigning the current service region by user selection.

8. The method of claim 1, further comprising identifying a control message from the received frames that includes an assignment of the home service region, and assigning a service region to the client home service region in response to the control message.

9. The method of claim 1, further comprising:

identifying a change control message from the received messages, wherein the control messages indicates that a change has occurred in the system;

receiving a new station list after the change control message; and

selecting the home station from the new station list, wherein the change in the system includes;

an old broadcast tower has gone off-line, a new broadcast tower is brought on-line, and a system reset is initiated.

10. The method of claim 1, wherein selecting a home station further comprises:

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

determining an assigned tower from the unique code; and

selecting the assigned tower for reception.

11. The method of claim 1, wherein selecting a home station further comprises:

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

determining a home station from the unique code; and

selecting the home station for reception.

12. The method of claim 11, wherein determining a home station from the unique code comprises determining 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.

13. The method of claim 12, wherein N corresponds to a 32-bit number from a 128-bit unique code.

14. The method of claim 11, wherein computing the unique code comprises:

selecting a unique identifier that is associated with the client device, applying the unique identifier as a seed to a code generator that provides a resulting code, and determining the unique code from the resulting code and an encryption string.

15. The method of claim 1, wherein initializing further comprises increasing the sample size when no valid signal is identified in the frequency sweep.

16. The method of claim 15, wherein initializing further comprises terminating the initialization when no valid signal is identified in the frequency sweep and the sample size is a maximum size.

17. The method of claim 1, wherein initialization further restarting the initialization when no valid signal is identified within the frequency sweep.

18. The method of claim 1, wherein initialization further restarting the initialization a maximum number of reties when no valid signal is identified within the frequency sweep.

19. A method for providing communication between broadcast towers and a client device, comprising:

selecting services with a scheduling interface;

scheduling a transmission of message content, wherein the message content corresponds to messages for at least one of the selected services;

assembling a frame with a frame header and the message content;

formatting the frame header with a service region identifier, wherein the service region identifier corresponds to a service region for a broadcast tower; and

transmitting the frame from the broadcast tower at a first scheduled time for reception by the client device.

20. The method of claim 19, wherein transmitting the frame further comprises transmitting the frame at a specified frequency that is in the range from 88 MHz to 107 MHz.

21. The method of claim 19, further comprising transmitting the selection of services to a broadcast server.

22. The method of claim 19, further comprising:

assembling another frame with another frame header and the message content;

formatting the other frame header with another service region identifier, wherein the other service region identifier corresponds to a service region for another broadcast tower; and

transmitting the other frame from the other broadcast tower at the first scheduled time for reception by the client device, whereby the client device may receive the message content at the first scheduled time.

23. The method of claim 22, wherein the broadcast tower and the other broadcast tower are geographically located in at least one of separated service regions, overlapping service regions, and contained service regions.

24. The method of claim 19, further comprising:

assembling another frame with another frame header and the message content;

formatting the other frame header with another service region identifier, wherein the other service region identifier corresponds to a service region for another broadcast tower; and

transmitting the other frame from the other broadcast tower at a second scheduled time for reception by the client device, whereby the client device receives the message content in the first service region and the second service region during a scheduled travel between the service region and the other service region.

25. The method of claim 19, further comprising:

encoding a station list in the frame header.

26. The method of claim 25, further comprising:

encoding control messages in the frame header.

27. The method of claim 19, further comprising:

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

selecting a personal message channel number in response to the unique code; and

assembling a personal message for the client device on the selected personal message channel.

28. The method of claim 27, wherein selecting the private message channel number from the unique code comprises:

determining a channel number as 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.

29. The method of claim 28, wherein N corresponds to a 32-bit number from a 128-bit unique code.

30. The method of claim 28, wherein computing the unique code comprises:

selecting a unique identifier that is associated with the client device;

applying the unique identifier to a code generator that provides a resulting code, wherein the unique identifier is a seed to the code generator; and

applying the resulting code to an encryption string to determine the unique code.