TERMINAL SYNCHRONIZATION METHOD AND APPARATUS FOR USE IN WIRELESS COMMUNICATION NETWORK

• US 20130336307A1
• Filed: 06/19/2013
• Published: 12/19/2013
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., SungKyunKwan University's Research & Business Foundation (SungKyunKwan University (SKKU))
• Original Assignee: Research & Business Foundation Of Sungkyunkwan University, Samsung Electronics Co. Ltd.
• Inventors: CHOI, Hyungjin, PARK, Seunghoon, WON, Kyunghoon, LEE, Kyunghoon, KIM, Kyungkyu, KIM, Daegyun, LIM, Chiwoo
• Granted Patent: US 10,051,586 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/002 Mutual synchronization

Abstract

A terminal synchronization method and apparatus for use in a wireless communication system are provided. A synchronization method includes configuring, at the terminal, a synchronization signal reference time depending on whether a synchronization signal is received in an initial observation period as long as at least two frames, monitoring to receive the synchronization signal in an alternation period of a transmission period and a reception period, the alternation period following the initial observation period, updating the reference time depending on whether the synchronization signal is received in the reception period, transmitting the synchronization signal at the updated reference time in the transmission period, and updating the reference time depending on whether the synchronization signal is received in a dedicated observation period following the alternation period. The synchronization apparatus and method are advantageous in that synchronization is obtained without assistance of a base station, an Access Point (AP), etc.

Claims

1. A synchronization method of a terminal, the method comprising:

configuring a synchronization signal reference time depending on whether a synchronization signal is received in an initial observation period as long as at least two frames;

monitoring to receive the synchronization signal in an alternation period of a transmission period and a reception period, the alternation period following the initial observation period;

updating the reference time depending on whether the synchronization signal is received in the reception period;

transmitting the synchronization signal at the updated reference time in the transmission period; and

updating the reference time depending on whether the synchronization signal is received in a dedicated observation period following the alternation period.

2. The method of claim 1, further comprising:

determining whether the terminal is in a synchronization lock state;

determining, when the terminal is in the synchronization lock state, whether a neighbor synchronization signal having a neighbor reference time different from the reference time of the synchronization signal of the terminal over a predetermined interval is received;

determining, when the neighbor reference signal is received, whether the neighbor reference signal indicates the synchronization lock state;

determining, when the neighbor reference signal indicates the synchronization lock state, whether the neighbor reference time is earlier than the reference time of the terminal; and

updating, when the neighbor reference time is earlier than the reference time of the terminal, the reference time of the terminal according to the neighbor synchronization signal.

3. The method of claim 1, further comprising increasing, when the neighbor synchronization signal is not received, the transmission period to be longer than the reception period in the alternation period.

4. The method of claim 1, further comprising:

determining whether a power of the received synchronization signal is greater than a predetermined threshold; and

suspending, when the power of the received synchronization signal is greater than the threshold, transmission of the synchronization signal in the transmission period.

5. The method of claim 4, further comprising restarting, when the power of the received synchronization signal is equal to or less than the threshold, the transmission of the synchronization signal in the transmission period.

6. The method of claim 2, further comprising observing, when the terminal is in the synchronization lock state, the synchronization signal in a predetermined period around the reference time of the terminal which is shorter than the reception period of the alternation period.

7. The method of claim 6, further comprising observing, when no synchronization signal is received in a predetermined period around the reference time of the terminal or when the received synchronization signal indicates change of the reference signal, the synchronization signal in the whole reception period.

15. A non-transitory computer-readable medium for storing instructions that, when executed, cause at least one processor to perform the method of claim 1.

8. A terminal for performing synchronization, the terminal comprising:

a communication unit configured to transmit and receive synchronization signals; and

a controller configured to control configuring a synchronization signal reference time depending on whether a synchronization signal is received in an initial observation period as long as at least two frames, monitoring to receive the synchronization signal in an alternation period of a transmission period and a reception period, the alternation period following the initial observation period, updating the reference time depending on whether the synchronization signal is received in the reception period, transmitting the synchronization signal at the updated reference time in the transmission period, and updating the reference time depending on whether the synchronization signal is received in a dedicated observation period following the alternation period.

9. The terminal of claim 8, wherein the controller is configured to control determining whether the terminal is in a synchronization lock state, determining, when the terminal is in the synchronization lock state, whether a neighbor synchronization signal having a neighbor reference time different from the reference time of the synchronization signal of the terminal over a predetermined interval is received, determining, when the neighbor reference signal is received, whether the neighbor reference signal indicates the synchronization lock state, determining, when the neighbor reference signal indicates the synchronization lock state, whether the neighbor reference time is earlier than the reference time of the terminal, and updating, when the neighbor reference time is earlier than the reference time of the terminal, the reference time of the terminal according to the neighbor synchronization signal.

10. The terminal of claim 9, wherein the controller is configured to increase, when the neighbor synchronization signal is not received, the transmission period to be longer than the reception period in the alternation period.

11. The terminal of claim 8, wherein the controller is configured to determine whether a power of the received synchronization signal is greater than a predetermined threshold and suspend, when the power of the received synchronization signal is greater than the threshold, transmission of the synchronization signal in the transmission period.

12. The terminal of claim 11, wherein the controller is configured to restart, when the power of the received synchronization signal is equal to or less than the threshold, the transmission of the synchronization signal in the transmission period.

13. The terminal of claim 9, wherein the controller is configured to observe, when the terminal is in the synchronization lock state, the synchronization signal in a predetermined period around the reference time of the terminal which is shorter than the reception period of the alternation period.

14. The terminal of claim 13, wherein the controller is configured to observe, when no synchronization signal is received in a predetermined period around the reference time of the terminal or when the received synchronization signal indicates change of the reference signal, the synchronization signal in the whole reception period.