System and method for timing synchronization

• US 9,226,250 B2
• Filed: 08/31/2011
• Issued: 12/29/2015
• Est. Priority Date: 11/20/2007
• Status: Active Grant

• Current Assignee: Blackberry Limited
• Original Assignee: Blackberry Limited
• Inventors: Jia, Yongkang, Womack, James Earl, Cai, Zhijun, Qu, Shouxing
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US13/223,075
• Publication Number:
  US 20110310861A1
• Time in Patent Office: 1,581 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks

Abstract

The present disclosure relates generally to systems and methods for timing synchronization. Uplink synchronization is a necessary component of a UE operating in a mobile, wireless network. Reliable uplink synchronization generally requires regular uplink transmission containing reference signals. A method is provided that defines a burst period for sending the reference signals, determines an interval between the reference signals, and sends a timing instruction message that includes the burst period and the determined interval. A second method is provided that receives the timing instruction message and sends the reference signals in accordance with the timing instruction.

Claims

1. A method in a network access equipment of maintaining uplink synchronization with a user equipment, the method comprising:

defining, by the network access equipment, a burst period for sending a plurality of timing signals, the burst period being defined within a timing advance (TA) adjustment period, the TA adjustment period including a quiet period during which the timing signals are not sent, wherein the quiet period includes a plurality of sub-frames;

sending, by the network access equipment, a first timing signal instruction message to the user equipment, wherein the first timing signal instruction message comprises a timing signal parameter, wherein the timing signal parameter is one or more of the burst period, a number of timing signals required per burst period to maintain synchronization, or an interval between ones of the timing signals in the burst period; and

receiving timing signals from the user equipment in accordance with the timing signal parameter; and

processing the timing signals in order to maintain synchronization.

2. The method of claim 1, wherein the TA adjustment period is about the same as a prior TA adjustment period.

3. The method of claim 1, further comprising:

determining, by the network access equipment, the number of timing signals required per burst period to maintain synchronization; and

determining, by the network access equipment, the interval between ones of the timing signals in the burst period.

4. The method of claim 3, further comprising ascertaining a repeating frequency of the timing signals in order to maintain synchronization.

5. The method of claim 4, wherein ascertaining a repeating frequency comprises estimating mobility of a user equipment.

6. The method of claim 3, wherein the first timing signal instruction further contains the TA adjustment period.

7. The method of claim 3, further comprising:

establishing, by the network access equipment, a change in the uplink timing alignment;

re-defining, by the network access equipment, the burst period for sending the plurality of timing signals;

re-determining, by the network access equipment, the interval between ones of the timing signals in the burst period; and

sending, by the network access equipment, a second timing signal instruction message containing one or more of the re-defined burst period or the re-determined interval.

8. The method of claim 7, wherein the change in uplink timing alignment is caused by a change in at least one of a location and a velocity of a user equipment.

9. A network access equipment configured for maintaining uplink synchronization with a user equipment, the network access equipment comprising:

a processor; and

memory storing instructions executable by the processor such that, when executed, the network access equipment is caused to;

define a burst period for sending a plurality of timing signals, the burst period being defined within a timing advance (TA) adjustment period, the TA adjustment period including a quiet period during which the timing signals are not sent, the quiet period including a plurality of sub-frames;

send a first timing signal instruction message to the user equipment, wherein the first timing signal instruction message comprises a timing signal parameter, wherein the timing signal parameter is one or more of the burst period, a number of timing signals required per burst period to maintain synchronization, or an interval between ones of the timing signals in the burst period;

receive timing signals from the user equipment in accordance with the timing signal parameter; and

process the timing signals in order to maintain synchronization.

10. The network access equipment of claim 9, wherein, when executed, the instructions executable by the processor further cause the network access equipment to define the TA adjustment period to be about the same as a prior TA adjustment period.

11. The network access equipment of claim 9, wherein, when executed, the instructions executable by the processor further cause the network access equipment to:

determine the number of timing signals required per burst period to maintain synchronization; and

generate the timing signal instruction message including one or more of the burst period or the number of timing signals.

12. The network access equipment of claim 11, wherein, when executed, the instructions executable by the processor further cause the network access equipment to ascertain a repeating frequency of the timing signals in order to maintain synchronization.

13. The network access equipment of claim 12, wherein, when executed, the instructions executable by the processor further cause the network access equipment to estimate mobility of a user equipment.

14. The network access equipment of claim 13, wherein, when executed, the instructions executable by the processor further cause the network access equipment to estimate at least one of absolute velocity and relative velocity of the user equipment, relative velocity being estimated with respect to movement of the user equipment away from or towards the network access equipment.

15. The network access equipment of claim 9, wherein, when executed, the instructions executable by the processor further cause the network access equipment to detect a change in uplink timing alignment caused by a change in at least one of a location and a velocity of a user equipment.

16. A user equipment (UE) comprising:

a processor; and

memory storing instructions executable by the processor such that, when executed, the UE is caused to;

receive a timing signal instruction message from a network access equipment, wherein the timing signal instruction message comprises a timing signal parameter, wherein the timing signal parameter is one or more of a burst period, a number of timing signals required per burst period to maintain synchronization, or an interval between ones of the timing signals in the burst period; and

transmit a plurality of timing signals to the network access equipment in accordance with the timing signal parameter during the defined burst period in order to maintain synchronization, the burst period being defined within a timing advance (TA) adjustment period, the TA adjustment period including a quiet period during which the UE does not transmit the timing signals, wherein the quiet period includes a plurality of sub-frames.

17. The UE of claim 16, wherein when executed, the instructions executable by the processor further cause the UE to receive:

the number of timing signals determined to be required per burst period to maintain synchronization; and

the interval between ones of the timing signals in the burst period.

18. The UE of claim 17, wherein a repeating frequency of the timing signals is ascertained in order to maintain synchronization.

19. The UE of claim 16, wherein, when executed, the instructions executable by the processor further cause the UE to measure an estimated velocity of the user equipment.

20. The UE of claim 19, wherein a change in an uplink timing alignment is established based upon the estimated velocity of the user equipment.

21. The UE of claim 19, wherein the interval is varied based upon the estimated velocity of the user equipment.

22. The UE claim 17, wherein the timing signal instruction further contains the TA adjustment period.

23. A method in a user equipment (UE) of maintaining uplink synchronization with a network access equipment, the method comprising:

receiving a timing signal instruction message from the network access equipment, wherein the timing signal instruction message comprises a timing signal parameter, wherein the timing signal parameter is one or more of a burst period, a number of timing signals required per burst period to maintain synchronization, or an interval between ones of the timing signals in the burst period; and

transmitting a plurality of timing signals to the network access equipment in accordance with the timing signal parameter during the defined burst period in order to maintain synchronization, the burst period being defined within a timing advance (TA) adjustment period, the TA adjustment period including a quiet period during which the UE does not transmit the timing signals, wherein the quiet period includes a plurality of sub-frames.

24. The method of claim 23, further comprising receiving:

the number of timing signals determined to be required per burst period to maintain synchronization; and

the interval between ones of the timing signals in the burst period.

25. The method of claim 24, wherein a repeating frequency of the timing signals is ascertained in order to maintain synchronization.

26. The method of claim 23, further comprising measuring an estimated velocity of the user equipment.

27. The method of claim 26, wherein a change in an uplink timing alignment is established based upon the estimated velocity of the user equipment.

28. The method of claim 26, wherein the interval is varied based upon the estimated velocity of the user equipment.

29. The method of claim 24, wherein the timing signal instruction further contains the TA adjustment period.