Tower discovery and failover

• US 20070058678A1
• Filed: 03/09/2006
• Published: 03/15/2007
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Corbea, Cosmin, Thompson, R.
• Granted Patent: US 7,746,885 B2
• Time in Patent Office: Days
• US Class Current: 370/471
• 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 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 associated with 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.

2. The method of claim 1, wherein transmitting the frame further comprises transmitting the frame at a specified frequency that is in the range from 88 MHz to 107 MHz.

3. The method of claim 1, wherein transmitting the frame further comprises transmitting the frame according to at least one of:

a frequency modulated (FM) transmission, and a sub-carrier based frequency modulated transmission.

4. The method of claim 1, further comprising transmitting the selection of services to a broadcast server.

5. The method of claim 1, 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.

6. The method of claim 5, 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.

7. The method of claim 1, 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.

8. The method of claim 1, further comprising:

encoding a station list in the frame header.

9. The method of claim 8, further comprising:

encoding control messages in the frame header.

10. The method of claim 1, 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.

11. The method of claim 10, further comprising:

encoding the personal message according to a unique control key associated with the client device.

12. The method of claim 10, 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.

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 12, 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.

15. The method of claim 1, further comprising:

encoding control information in at least one frame header.

16. The method of claim 15, wherein the control information comprises 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 a particular 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.

17. The method of claim 1, further comprising:

encoding 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.

18. The method of claim 17, wherein the data sync pattern is encoded in a distributed manner over several segments of the transmission.

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

a means for selecting services with a scheduling interface;

a means for scheduling a transmission of a message payload, wherein the message payload is associated with at least one of the selected services;

a means for assembling a transmission frame with a frame header and the message payload;

a means for formatting the frame header with a service region identifier, wherein the service region identifier is associated with a service region for a broadcast tower;

a means for encoding the transmission frame for valid reception by the at least one client device; and

a means for scheduling a broadcast time for the transmission frame; and

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

20. The method of claim 19, further comprising a means for identifying a unique code associated with a particular client device, wherein the means for encoding is arranged to apply the identified unique code for each transmission that includes a personal message associated with the particular client device.