Method for receiving and transmitting synchronization signal and wireless communication device

• US 10,425,220 B2
• Filed: 12/27/2016
• Issued: 09/24/2019
• Est. Priority Date: 05/12/2016
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Tsai, Hua-Lung, Sheu, Chorng-Ren, Wei, Chun-Yi
• Primary Examiner(s): Tadese, Berhanu
• Application Number:
  US15/391,508
• Publication Number:
  US 20170331620A1
• Time in Patent Office: 1,001 Days
• Field of Search: None
• CPC Class Codes: H04L 47/17 Interaction among intermediate nodes, e.g. hop by hop
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 7/042 Detectors therefor, e.g. correlators, state machines digital correlators in general G06F17/15
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 84/00 Network topologies

Abstract

A method for receiving and transmitting synchronization signal is provided. The method is applicable to a wireless communication device. The wireless communication device has a local timing. The method includes the following steps. Receive at least one synchronization signal. If a signal power of at least one of the at least one synchronization signal is greater than or equal to a signal power threshold, select one of the at least one synchronization signal as a reference synchronization signal according to a priority rule, and synchronize the local timing to the reference synchronization signal. If the signal power of each the synchronization signal is less than the signal power threshold, send a local synchronization signal according to the local timing. If the reference synchronization signal meets a forwarding criterion, forward the reference synchronization signal, wherein the forwarding criterion includes a power constraint and a hop count constraint.

Claims

1. A method for receiving and transmitting synchronization signal, applicable to a wireless communication device, the wireless communication device having a local timing, and the method comprises:

receiving at least one synchronization signal;

if a signal power of at least one of the at least one synchronization signal is greater than or equal to a signal power threshold, selecting one of the at least one synchronization signal as a reference synchronization signal according to a priority rule, and synchronizing the local timing to the reference synchronization signal;

if the signal power of each the synchronization signal is less than the signal power threshold, sending a local synchronization signal according to the local timing; and

if the reference synchronization signal meets a forwarding criterion, forwarding the reference synchronization signal, wherein the forwarding criterion comprises a power constraint and a hop count constraint,

wherein the forwarding criterion comprises a hop count of the reference synchronization signal is less than a hop count threshold.

2. The method according to claim 1, wherein the synchronization signal is sent from a transmission source, and the transmission source is a base station, a global navigation satellite system, or a user equipment.

3. The method according to claim 2, wherein the power constraint is determined according to the transmission source of the reference synchronization signal.

4. The method according to claim 2, wherein the forwarding criterion comprises:

the signal power of the reference synchronization signal is between a power lower bound and a power upper bound;

wherein the hop count represents a number of forwarding operations that the reference synchronization signal has experienced after being sent from the base station or the global navigation satellite system.

5. The method according to claim 2, wherein the priority rule comprises:

prioritizing either a synchronization signal related to the base station or a synchronization signal related to the global navigation satellite system according to a synchronization source indicator; and

assigning equal priority order to the synchronization signal related to the base station and the synchronization signal related to the global navigation satellite system when the synchronization source indicator is not received;

wherein the synchronization source indicator is transmitted from the base station to the wireless communication device.

6. The method according to claim 2, wherein the priority rule comprises:

assigning a higher priority order to a synchronization signal whose transmission source is in a coverage of the base station than to a synchronization signal whose transmission source is out of the coverage of the base station.

7. The method according to claim 2, wherein the priority rule comprises:

based on a hop count of the at least one synchronization signal, sorting the hop count in an ascending order, and assigning a higher priority order to a synchronization signal having the smaller hop count than to a synchronization signal having the larger hop count.

8. The method according to claim 2, wherein the priority rule comprises:

based on the signal power of the at least one synchronization signal, sorting the signal power in a descending order, and assigning a higher priority order to a synchronization signal having the larger signal power than to a synchronization signal having the smaller signal power.

9. The method according to claim 2, wherein the at least one synchronization signal comprises a first synchronization signal and a second synchronization signal, the first synchronization signal is related to the base station, the second synchronization signal is related to the global navigation satellite system, the method further comprises:

detecting a time gap between the first synchronization signal and the second synchronization signal.

10. The method according to claim 9, further comprising transmitting the time gap.

11. The method according to claim 9, further comprising:

obtaining a first frame number of the first synchronization signal;

obtaining a second frame number of the second synchronization signal; and

calculating a time difference between the base station and the global navigation satellite system according to the first frame number, the second frame number, and the time gap.

12. The method according to claim 11, further comprising transmitting the time difference to the base station.

13. The method according to claim 9, wherein the transmission source of the first synchronization signal is the base station, and the step of detecting the time gap between the first synchronization signal and the second synchronization signal comprises:

obtaining a time difference between the base station and the global navigation satellite system from the base station;

obtaining a first frame number of the first synchronization signal;

obtaining a second frame number of the second synchronization signal; and

calculating the time gap according to the first frame number, the second frame number, and the time difference between the base station and the global navigation satellite system.

14. A wireless communication device, the wireless communication device having a local timing, the wireless communication device comprising:

a signal transceiver, configured to receive at least one synchronization signal; and

a processor, coupled to the signal transceiver, the processor configured to perform the following operations;

if determining that a signal power of at least one of the at least one synchronization signal is greater than or equal to a signal power threshold, selecting one of the at least one synchronization signal as a reference synchronization signal according to a priority rule, and synchronizing the local timing to the reference synchronization signal;

if determining that the signal power of each the synchronization signal is less than the signal power threshold, sending a local synchronization signal according to the local timing by the signal transceiver; and

if determining that the reference synchronization signal meets a forwarding criterion, forwarding the reference synchronization signal by the signal transceiver, wherein the forwarding criterion comprises a power constraint and a hop count constraint,

wherein the forwarding criterion comprises a hop count of the reference synchronization signal is less than a hop count threshold.

15. The wireless communication device according to claim 14, wherein the synchronization signal is sent from a transmission source, the transmission source is a base station, a global navigation satellite system, or a user equipment.

16. The wireless communication device according to claim 15, wherein the power constraint is determined according to the transmission source of the reference synchronization signal.

17. The wireless communication device according to claim 15, wherein the forwarding criterion comprises:

the signal power of the reference synchronization signal is between a power lower bound and a power upper bound;

wherein the hop count represents a number of forwarding operations that the reference synchronization signal has experienced after being sent from the base station or the global navigation satellite system.

18. The wireless communication device according to claim 15, wherein the priority rule comprises:

prioritizing either a synchronization signal related to the base station or a synchronization signal related to the global navigation satellite system according to a synchronization source indicator; and

assigning equal priority order to the synchronization signal related to the base station and the synchronization signal related to the global navigation satellite system when the synchronization source indicator is not received;

wherein the synchronization source indicator is transmitted from the base station to the wireless communication device.

19. The wireless communication device according to claim 15, wherein the priority rule comprises:

assigning a higher priority order to a synchronization signal whose transmission source is in a coverage of the base station than to a synchronization signal whose transmission source is out of the coverage of the base station.

20. The wireless communication device according to claim 15, wherein the priority rule comprises:

based on a hop count of the at least one synchronization signal, sorting the hop count in an ascending order, and assigning a higher priority order to a synchronization signal having the smaller hop count than to a synchronization signal having the larger hop count.

21. The wireless communication device according to claim 15, wherein the priority rule comprises:

based on the signal power of the at least one synchronization signal, sorting the signal power in a descending order, and assigning a higher priority order to a synchronization signal having the larger signal power than to a synchronization signal having the smaller signal power.

22. The wireless communication device according to claim 15, wherein the at least one synchronization signal comprises a first synchronization signal and a second synchronization signal, the first synchronization signal is related to the base station, the second synchronization signal is related to the global navigation satellite system, the processor is further configured to perform the following operation:

detecting a time gap between the first synchronization signal and the second synchronization signal.

23. The wireless communication device according to claim 22, wherein the signal transceiver is further configured to transmit the time gap.

24. The wireless communication device according to claim 22, wherein the processor is further configured to perform the following operations:

obtaining a first frame number of the first synchronization signal;

obtaining a second frame number of the second synchronization signal; and

calculating a time difference between the base station and the global navigation satellite system according to the first frame number, the second frame number, and the time gap.

25. The wireless communication device according to claim 24, wherein the signal transceiver is further configured to transmit the time difference to the base station.

26. The wireless communication device according to claim 22, wherein the transmission source of the first synchronization signal is the base station, and the processor is further configured to perform the following operations:

obtaining a time difference between the base station and the global navigation satellite system from the base station;

obtaining a first frame number of the first synchronization signal;

obtaining a second frame number of the second synchronization signal; and

calculating the time gap according to the first frame number, the second frame number, and the time difference between the base station and the global navigation satellite system.