Method and apparatus for sending a channel timing message in a digital mobile radio system

• US 8,983,513 B2
• Filed: 11/30/2010
• Issued: 03/17/2015
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Khoo, Hun Weng, Chung, Yueh Ching, Wiatrowski, David G.
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US12/957,009
• Publication Number:
  US 20120135765A1
• Time in Patent Office: 1,568 Days
• Field of Search: 455/434, 455/436, 455/502, 455/507, 455/512, 455/513, 455/515, 375/354, 375/356, 375/357
• US Class Current: 455/507
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/0075 based on arrival time vs. expected arrival time
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

A method and apparatus for automatically switching functions associated with a leading radio to another radio on a channel is disclosed. The method includes receiving, from a leading radio by at least one other radio operating on a channel, an associated timing signal via at least one control timing message. Other radios use the timing signal to synchronize transmissions made on the channel. The method also includes receiving, by the other radios, an indication that the leading radio can no longer provide control timing messages. The method further includes maintaining, by each radio on the channel, values for various elements associated with radios operating on the channel and selecting a new leading radio from the other radios based on priorities of the various elements.

Claims

1. A method for automatically switching functions associated with a leading radio to another radio operating on a channel comprising:

receiving, from a leading radio by at least one of a plurality of other radios operating on a channel, an associated timing signal via at least one control timing message, wherein the at least one of the plurality of other radios use the timing signal to synchronize transmissions made on the channel;

receiving, by the at least one of the plurality of other radios, an indication that the leading radio can no longer provide control timing messages;

maintaining, by each of the plurality of other radios operating on the channel, values for various elements associated with each of the plurality of other radios operating on the channel, wherein the various elements include at least a field indicating a preference of each of the plurality of other radios for selection as a new leading radio; and

selecting, by the at least one of the plurality of other radios, the new leading radio from the plurality of other radios based on priorities of the various elements.

2. The method according to claim 1, wherein the maintaining comprises maintaining values for a subscriber identifier field, a radio type field including the field indicating the preference of the each of the other radios for selection as the new leading radio, a timeslot field, and a synchronization age field.

3. The method of claim 2, wherein upon receiving the control timing messages, the method further comprises using, by the one or more plurality of other radios, the value in the synchronization age field associated with the leading radio.

4. The method of claim 2, wherein the selecting comprises selecting the new leading radio based on prioritized values in the radio type field.

5. The method of claim 4, wherein if at least two of the plurality of other radios have the same value in associated radio type fields, the selecting comprises selecting the new leading radio based on prioritized values in the subscriber identifier field.

6. The method of claim 2, wherein each of the plurality of other radios operating on the channel sorts the various elements based on values in the radio type field and the subscriber identifier field and associates a status field with each of the plurality of other radios.

7. The method of claim 6, wherein the selecting comprises automatically selecting the new leading radio according to the value in the status field.

8. The method of claim 1, wherein the receiving the associated timing signal further comprises receiving a predefined number of control timing messages from the leading radio during a synchronization period.

9. The method of claim 8, wherein the receiving an indication comprises receiving no control timing messages from the leading radio during the synchronization period and a hold-off period.

10. The method of claim 1, further comprising transmitting, by the one or more at least one of the plurality of other radios, a timing reference message in a packet, wherein the timing reference message includes a timing signal transmitted from the leading radio.

11. The method of claim 1, further comprising receiving, by the one or more at least one of the plurality of other radios, the control timing messages transmitted from the leading radio during a hold-off time and when the channel is idle.

12. The method of claim 1, further comprising synchronizing, by the one or more at least one of the plurality of other radios, transmissions on all timeslots on the channel based on the control timing messages transmitted from the leading radio in an assigned timeslot.

13. The method of claim 1, further comprising allowing at least one of the plurality of other radios to transmit an announcement that it can be the new leading radio.

14. The method of claim 1, wherein the selecting further comprises:

determining, by the at least one of the plurality of other radios, a priority for each of the plurality of other radios based on the values for various elements associated with each of the plurality of other radios operating on the channel; and

selecting, by the at least one of the plurality of other radios, the new leading radio from the plurality of other radios based on the priority determined for each of the plurality of other radios.

15. The method of claim 1, wherein the maintaining further comprises:

receiving, by each of the plurality of other radios, values for the various elements associated with the at least one other radio of the plurality of other radios from the at least one other radio of the plurality of other radios; and

maintaining, by each of the plurality of other radios operating on the channel, the received values.

16. A system configured to automatically switch functions associated with a leading radio to another radio operating on a channel, the system comprising:

a leading radio; and

at least one a plurality of other radios operating on a channel,

wherein the leading radio is configured to transmit an associated timing signal by transmitting at least control timing message to at least one of the plurality of other radios, wherein one or more the at least one of the plurality of other radios use the timing signal to synchronize transmissions made on the channel, and

wherein each of the one or more plurality of other radios is configured to receive an indication that the leading radio can no longer provide the control timing messages, to maintain values for various elements associated with one or more each of the plurality of other radios operating on the channel, and to select a new leading radio from the plurality of other radios based on priorities of the various elements, further wherein the various elements include at least a field indicating a preference of each of the plurality of other radios for selection as the new leading radio.

17. The system according to claim 16, wherein each of the plurality of other radios is configured to maintain values for a subscriber identifier field, a radio type field including the field indicating the preference of the each of the other radios for selection as the new leading radio, a timeslot field, and a synchronization age field.

18. The system according to claim 17, wherein each of the one or more plurality of other radios is configured to select the new leading radio based on prioritized radio type values, wherein if at least two of the other radios have the same value in the radio type field, the one or more plurality of other radios are configured to select the new leading radio based on prioritized values in the subscriber identifier field.

19. The system of claim 16, wherein each of the plurality of other radios operating on the channel is configured to sort the various elements based on values in the radio type field and the subscriber identifier field, and to associate a status field with each radio, wherein the one or more plurality of other radios are configured to select the new leading radio according to a value in the status field.

20. The system of claim 16, wherein each of the plurality of other radios is further configured to determine a priority for each of the plurality of other radios based on the values for various elements associated with each of the plurality of other radios operating on the channel and select the new leading radio from the plurality of other radios based on the priority determined for each of the plurality of other radios.