Method for synchronizing a control channel to a working channel

• US 20040190487A1
• Filed: 03/31/2003
• Published: 09/30/2004
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Biggs, Robert A.
• Granted Patent: US 6,882,663 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04J 3/0652 Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP] bus network with centralized control in which slots are of a TDMA packet structure H04L12/4035

Abstract

A subscriber unit (104) listens to a first channel (202) comprising a plurality of micro-slots and a plurality of data units. The subscriber unit decodes at least a portion of a data unit on the first channel comprising a micro-slot value. The subscriber unit learns the synchronization between the first channel and a second channel (206/300) based on the micro-slot value. A first base radio (106₁) transmits a first plurality of data units on the first channel. A second base radio (106₃) transmits a second plurality of data units on the second channel. The first plurality of micro-slots on the first channel are synchronized with the second plurality of micro-slots or plurality of frame boundaries on the second channel. The first base radio transmits a message (406) on the first channel in at least one of the plurality of data units, wherein the message comprises at least a micro-slot value used to associate the synchronization between the first channel and the second channel.

Claims

1. A method comprising the steps of:

listening to a first channel comprising a plurality of micro-slots and a plurality of data units;

decoding at least a portion of a data unit on the first channel comprising a micro-slot value; and

learning a synchronization between the first channel and a second channel based on the micro-slot value.

2. The method of claim 1 wherein the micro-slot value identifies one of a beginning and an end of the current data unit.

3. The method of claim 1 wherein the first channel is a control channel, and the second channel is a working channel.

4. The method of claim 1 wherein the second channel is a time division multiple access working channel.

5. The method of claim 4 further comprising the steps of:

receiving an assignment on the first channel to operate on the second channel;

calculating a slot boundary on the second channel from the micro-slot value; and

operating on the second channel at the slot boundary.

6. The method of claim 1 wherein the second channel is a frequency division multiple access working channel.

7. The method of claim 6 further comprising the steps of:

receiving an assignment on the first channel to operate on the second channel;

calculating a micro-slot boundary on the second channel from the micro-slot value; and

operating on the second channel at the micro-slot boundary.

8. The method of claim 1 further comprising the step of using the micro-slot value to keep time locally in order to track synchronization between the first channel and the second channel.

9. The method of claim 8 further comprising the steps of:

terminating the step of listening to the first channel;

listening to the second channel for a beginning of a next data unit upon the step of terminating;

determining a micro-slot value associated with the beginning of the next data unit; and

using the micro-slot value associated with the beginning of the next data unit to decrypt the next data unit.

10. The method of claim 8 further comprising the steps of:

terminating the step of listening to the first channel;

determining a subsequent micro-slot value to transmit a data unit on the second channel; and

using the subsequent micro-slot value to encrypt the data unit on the second channel.

11. The method of claim 1 further comprising the step of counting at least one micro-slot from the first channel in order to track synchronization between the first channel and the second channel.

12. The method of claim 1 wherein the plurality of micro-slots have a numbering scheme, and further comprising the step of having a priori knowledge of the numbering scheme used for the plurality of micro-slots.

13. The method of claim 1 wherein the plurality of data units are of varying lengths.

14. A method comprising the steps of:

transmitting a first plurality of data units on a first channel, wherein the first channel comprises a first plurality of micro-slots;

transmitting a second plurality of data units on a second channel, wherein the second channel comprises a second plurality of micro-slots, and wherein the first plurality of micro-slots are synchronized with the second plurality of micro-slots; and

transmitting a message on the first channel in at least one of the plurality of data units, wherein the message comprises at least a micro-slot value used to associate the synchronization between the first channel and the second channel.

15. The method of claim 14 further comprising the steps of:

receiving an encrypted data unit on the second channel at a given micro-slot value; and

decrypting the data unit using the given micro-slot value.

16. The method of claim 14 further comprising the steps of:

transmitting an encrypted data unit on the second channel at a given micro-slot value, wherein the data unit is encrypted using the given micro-slot value.

17. The method of claim 14 wherein the plurality of data units are of varying lengths.

18. A method comprising the steps of:

transmitting a plurality of data units on a first channel, wherein the first channel comprises a plurality of micro-slots;

transmitting a plurality of time division multiple access (“

TDMA”

) frames on a second channel, wherein the second channel comprises a plurality of frame boundaries, and wherein the plurality of frame boundaries are synchronized with the plurality of micro-slots; and

transmitting a message on the first channel in at least one of the plurality of data units, wherein the message comprises at least a micro-slot value used to associate the synchronization between the first channel and the second channel.

19. The method of claim 18 wherein the each frame boundary comprises at least one slot boundary, and further comprising the steps of:

receiving an encrypted data unit on the second channel at a given slot boundary; and

decrypting the data unit using the given slot boundary.

20. The method of claim 18 wherein the each frame boundary comprises at least one slot boundary, and further comprising the steps of:

transmitting an encrypted data unit on the second channel at a given slot boundary, wherein the data unit is encrypted using the given slot boundary.

21. The method of claim 18 wherein the plurality of data units are of varying lengths.