Transmitting a synchronization indication

Patent metadata

Field	Value
Publication number	US-9408167-B2
Application number	US-201314002371-A
Country	US
Kind code	B2
Filing date	May 3, 2013
Priority date	May 3, 2013
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A first wireless access network node sets a synchronization indication based on whether the first wireless access network node is synchronized with a synchronization source. The first wireless access network node transmits the synchronization indication.

First claim

What is claimed is:

1. A method comprising:
attempting, by a first small cell wireless access network node, to synchronize with a second small cell wireless access network node that is synchronized to a synchronization source;
in response to the first small cell wireless access network node being able to synchronize with the second small cell wireless access network node that is synchronized to the synchronization source, setting, by the first small cell wireless access network node, a first synchronization indication based on a second synchronization indication received by the first small cell wireless access network node from the second small cell wireless access network node;
in response to the first small cell wireless access network node being unable to synchronize with the second small cell wireless access network node that is synchronized with the synchronization source, the first small cell wireless access network node:
determining whether the first small cell wireless access network node is able to synchronize with a macro cell or a global positioning system (GPS) receiver, and
in response to determining that the first small cell wireless access network node is able to synchronize with the macro cell or the GPS receiver, setting a third synchronization indication different from the second synchronization indication, and responsive to detecting a conflict condition in which the first small cell wireless access network node and at least another small cell wireless access network node have set the third synchronization indication, performing an operation to resolve the conflict condition to change the third synchronization indication of one of the first small cell wireless access network node and the at least another small cell wireless access network node to a different synchronization indication.

2. The method of claim 1 , wherein the first synchronization indication is an explicit indication or an implicit indication.

3. The method of claim 1 , further comprising:
joining, by the first small cell wireless access network node, a cluster of small cell wireless access network nodes including the second small cell wireless access network node.

4. The method of claim 1 , wherein setting the first synchronization indication comprises setting synchronization information to one of a plurality of values, a first of the values indicating that the first small cell wireless access network node is un-synchronized with any synchronization source, a second of the values indicating that the first small cell wireless access network node is synchronized with the macro cell or the GPS receiver, and a third of the values indicating that the first small cell wireless access network node is synchronized with a small cell.

5. The method of claim 4 , wherein the third value indicates that the first small cell wireless access network node is synchronized with the second small cell wireless access network node that has synchronization information set to the second value, and the plurality of values further include a fourth value indicating that the first small cell wireless access network node is synchronized to a small cell that has synchronization information set to the third value.

6. The method of claim 5 , wherein the first small cell wireless access network node is part of a cluster that has cells in a plurality of tiers indicated by different values of synchronization information of corresponding small cell wireless access network nodes that are part of the cells in the cluster.

7. The method of claim 1 , wherein transmitting the first synchronization indication comprises transmitting the first synchronization indication in system information broadcast wirelessly by the first small cell wireless access network node.

8. The method of claim 1 , further comprising:
in response to the second synchronization indication received from the second small cell wireless access network node having a first value, joining, by the first small cell wireless access network node, a cluster of cells that includes the second small cell wireless access network node.

9. The method of claim 1 , further comprising:
reporting, by the first small cell wireless access network node to another small cell wireless access network node, information regarding cells synchronized to the first small cell wireless access network node.

10. The method of claim 1 , further comprising:
in response to the first small cell wireless access network node being unable to synchronize with the macro cell or the GPS receiver, the first small cell wireless access network node:
detecting a third small cell wireless access network node associated with synchronization information set to a value indicating that the third small cell wireless access network node is un-synchronized, and
cooperating with the third small cell wireless access network node to determine which of the first and third small cell wireless access network nodes is to be an anchor node for a cluster of cells.

11. The method of claim 1 , wherein transmitting the first synchronization indication comprises transmitting one of a plurality of different synchronization signals for indicating corresponding different synchronization states.

12. The method of claim 11 , wherein an association is configured between the synchronization signals and the different synchronization states.

13. The method of claim 11 , wherein the synchronization signals include one or more of primary synchronization signals, secondary synchronization signals, and tracking reference signals.

14. The method of claim 11 , wherein the different synchronization signals are distinguishable from each other due to one or more of different sequences of the corresponding different synchronization signals, and different resources for carrying the different synchronization signals.

15. The method of claim 11 , further comprising:
in response to a synchronization state of the first small cell wireless access network node changing, associating the first small cell wireless access network node with another synchronization signal or changing an association between synchronization signals and corresponding synchronization states.

16. The method of claim 1 , further comprising:
detecting, by the first small cell wireless access network node, deactivation of the second small cell wireless access network node of a cell in a cluster of cells, wherein the first small cell wireless access network node was synchronized to the second small cell wireless access network node prior to deactivation of the second small cell wireless access network node; and
in response to the detected deactivation of the second small cell wireless access network node, synchronizing, by the first small cell wireless access network node, with a third small cell wireless access network node of a cell in the cluster of cells.

17. The method of claim 1 , further comprising:
detecting, by the first small cell wireless access network node, deactivation of an anchor node of a cluster of cells;
in response to the detected deactivation of the anchor node, determining that the first small cell wireless access network node is able to synchronize with the macro cell or the GPS receiver; and
in response to determining that the first small cell wireless access network node is able to synchronize with the macro cell or the GPS receiver, updating the first synchronization indication to indicate that the first wireless access network node is an anchor node of the cluster.

18. The method of claim 1 , further comprising:
detecting, by

Assignees

• Blackberry Ltd

Inventors

• Zhu Yajun
• Cai Zhijun
• Xu Hua
• Gao Shiwei

Classifications

• H04W56/0015

  one node acting as a reference for the others · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title