System and method for timing synchronization

• US 8,031,693 B2
• Filed: 11/20/2007
• Issued: 10/04/2011
• Est. Priority Date: 11/20/2007
• Status: Active Grant

• Current Assignee: Blackberry Limited
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Womack, James Earl, Qu, Shouxing, Cai, Zhijun, Jia, Yongkang
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US11/943,417
• Publication Number:
  US 20090129312A1
• Time in Patent Office: 1,414 Days
• Field of Search: None
• US Class Current: 370/350
• 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 comprising:

defining, by the network access equipment, a burst period for sending a plurality of timing signals, wherein the burst period is defined within a timing advance (TA) adjustment period comprising a measurement period and a quiet period, wherein the burst period corresponds to the measurement period, and wherein the quiet period corresponds to a time during the TA adjustment period in which sending the timing signals is avoided;

determining a number of timing signals required per burst period to maintain synchronization, the number being such that, relative to a prior TA adjustment period, a total number of timing signals within the TA adjustment period remains constant, and wherein the burst period is shorter than the prior TA adjustment period;

determining an interval between ones of the plurality of timing signals in the burst period; and

sending a timing signal instruction message containing the burst period and the interval.

2. The method of claim 1, wherein the timing signal instruction message further contains the quiet period.

3. The method of claim 1, wherein determining an interval includes ascertaining a repeating frequency of the timing signals in order to maintain synchronization.

4. The method of claim 3, wherein ascertaining a repeating frequency includes estimating mobility of a user equipment.

5. The method of claim 1, further comprising:

establishing a change in a uplink timing alignment;

re-defining the burst period for sending the plurality of timing signals;

re-determining an interval between ones of the plurality of timing signals in the burst period; and

sending a second timing signal instruction message containing the re-defined burst period at the re-determined interval.

6. The method of claim 5, wherein the change in uplink timing alignment is caused by a change in a mobility of an user equipment.

7. A system for maintaining uplink synchronization in a network access equipment comprising:

a synchronization timing instruction module comprising;

a burst period module configured to define a burst period for sending

a plurality of timing signals, wherein the burst period is defined within a timing advance (TA) adjustment period comprising a measurement period and a quiet period, wherein the burst period corresponds to the measurement period, and wherein the quiet period corresponds to a time during the TA adjustment period in which sending the timing signals is avoided;

an interval module configured to determine a number of timing signals required per burst period to maintain synchronization, the number being such that, relative to a prior TA adjustment period a total number of timing signals within the TA adjustment period remains constant, and wherein the interval module is further configured to determine an interval between ones of the plurality of timing signals in the burst period; and

a message generator module coupled with the burst period module and the interval module, the message generator module configured to generate a timing signal instruction message comprising the burst period and the determined interval.

8. The system of claim 7, wherein the timing signal instruction message further comprises the quiet period.

9. The system of claim 7, wherein the interval module further comprises a frequency control module configured to ascertain a repeating frequency of the timing signals in order to maintain synchronization.

10. The system of claim 9, wherein the frequency control module includes an estimating module configured to estimate mobility of a user equipment, based upon receipt of the plurality of timing signals form the user equipment.

11. The system of claim 7, wherein the network access equipment is in a wireless, mobile system.

12. A method for uplink synchronization in an user equipment comprising:

Receiving, at the user equipment, a timing signal instruction message comprising a burst period, wherein the burst period is defined within a timing advance (TA) adjustment period comprising a measurement period and a quiet period, wherein the burst period corresponds to the measurement period and wherein the quiet period corresponds to a time during the TA adjustment period in which sending the timing signals is avoided, and wherein the timing signal instruction message further comprises an interval including a number of timing signals required per burst period to maintain synchronization, the number being such that, relative to a prior TA adjustment period, a total number of timing signals within the TA adjustment period remains constant, and wherein the burst period is shorter than the prior TA adjustment period; and

transmitting the number of timing signals for the burst period at the interval.

13. The method of claim 12, further comprising:

transmitting timing signals during the burst period at the interval;

waiting for a duration of the quiet period; and

transmitting timing signals during the burst period at the interval.

14. The method of claim 12, further comprising:

obtaining mobility information; and

sending the mobility information.

15. The method of claim 12, further comprising:

estimating a mobility of the user equipment; and

sending the estimate.

16. A method for maintaining uplink synchronization in a wireless network comprising:

at a network access equipment;

defining a burst period for sending a plurality of timing signals, wherein the burst period is defined within a timing advance (TA) adjustment period comprising a measurement period and a quiet period, wherein the burst period corresponds to the measurement period, and wherein the quiet period corresponds to a time during the TA adjustment period in which sending the timing signals is avoided;

determining a number of timing signals required per burst period to maintain synchronization, the number being such that, relative to a prior TA adjustment period, a total number of timing signals within the TA adjustment period remains constant, and wherein the burst period is shorter than the prior TA adjustment period;

determining an interval between ones of the plurality of timing signals in the burst period; and

sending a timing signal instruction message containing the burst period and interval;

at a user equipment;

receiving the timing signal instruction; and

sending the plurality of timing signals in accordance with the timing signal instruction.

17. The method of claim 16, further comprising:

transmitting from the user equipment the timing signals for the burst period at the interval;

waiting for a duration of the quiet period; and

transmitting timing signals for the burst period at the interval.

18. The method of claim 16, further comprising:

determining a change in timing synchronization;

re-defining the burst period for sending the plurality of timing signals;

re-determining an interval between ones of the plurality of timing signals in the burst period;

sending a second timing signal instruction message containing the re-defined burst period at the re-determined interval, wherein the user equipment receives the second timing signal instruction message and sends the plurality of timing signals in accordance with the second timing signal instruction message.