Fast timing acquisition in cell search

• US 9,059,785 B2
• Filed: 07/07/2011
• Issued: 06/16/2015
• Est. Priority Date: 07/07/2011
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Fertonani, Dario, Khandekar, Aamod Dinkar, Gummadi, Srikanth, Black, Peter John
• Primary Examiner(s): HOANG, THAI D
• Application Number:
  US13/178,374
• Publication Number:
  US 20130010780A1
• Time in Patent Office: 1,440 Days
• Field of Search: 370/252, 370342-345, 370/456
• US Class Current: 1/1
• CPC Class Codes: H04B 1/7073 Synchronisation aspects
• CPC Class Codes: H04B 1/70735 Code identification H04B1/7083 takes precedence
• CPC Class Codes: H04B 2201/70718 Particular systems or standards

Abstract

Timing acquisition may be performed without typical correlation computations by determining a power of a received signal at certain points in time and using the determined power to identify gaps in the received signal. By determining gaps in the received signal, frame timing may be estimated, particularly in time-division networks where the location of guard periods within a frame is known. Gap detection may thus be used for timing acquisition.

Claims

1. A method of detecting frame timing in a wireless communication network, the method comprising:

determining a set of received powers at different sequential portions of a frame; and

detecting a gap in transmission based on a ratio of a minimum received power of a first and third of the sequential portions relative to a maximum received power of a second and fourth of the sequential portions, the first sequential portion, second sequential portion, third sequential portion, and fourth sequential portion being sequential in time.

2. The method of claim 1 in which the wireless communication network comprises a Time Division-Synchronous Code Division Multiple Access network.

3. The method of claim 2 in which the gap in transmission comprises a gap between a first time slot of a subframe and a synchronization downlink (SYNC-DL) field of a downlink pilot time slot in the subframe.

4. The method of claim 2 in which the gap in transmission is a gap between a downlink pilot time slot in a subframe and a next time slot in the subframe.

5. The method of claim 1 in which the set of received powers comprises received powers taken at different portions of the frame, where the different portions are selected based on a length of a frame time slot.

6. The method of claim 1 further comprising determining a frame timing from the gap in transmission.

7. The method of claim 1 further comprising determining pilot correlations to obtain a frame timing and a serving cell identity.

8. The method of claim 1 in which the determining a set of received powers comprises calculating a set of power profiles.

9. A computer program product for detecting frame timing in a wireless communication network, the computer program product comprising:

a non-transitory computer-readable medium having non-transitory program code recorded thereon, the program code comprising;

program code to determine a set of received powers at different sequential portions of a frame; and

program code to detect a gap in transmission based on a ratio of a minimum received power of a first and third of the sequential portions relative to a maximum received power of a second and fourth of the sequential portions, the first sequential portion, second sequential portion, third sequential portion, and fourth sequential portion being sequential in time.

10. An apparatus for detecting frame timing in a wireless communication network, the apparatus comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor being configured;

to determine a set of received powers at different sequential portions of a frame; and

to detect a gap in transmission based on a ratio of a minimum received power of a first and third of the sequential portions relative to a maximum received power of a second and fourth of the sequential portions, the first sequential portion, second sequential portion, third sequential portion, and fourth sequential portion being sequential in time.

11. The apparatus of claim 10 in which the wireless communication network comprises a Time Division-Synchronous Code Division Multiple Access network.

12. The apparatus of claim 11 in which the gap in transmission comprises a gap between a first time slot of a subframe and a synchronization downlink (SYNC-DL) field of a downlink pilot time slot in the subframe.

13. The apparatus of claim 11 in which the gap in transmission is a gap between a downlink pilot time slot in a subframe and a next time slot in the subframe.

14. The apparatus of claim 10 in which the set of received powers comprises received powers taken at different portions of the frame, where the different portions are selected based on a length of a frame time slot.

15. The apparatus of claim 10 in which the at least one processor is further configured to determine a frame timing from the gap in transmission.

16. The apparatus of claim 10 in which the at least one processor is further configured to determine pilot correlations to obtain a frame timing and a serving cell identity.

17. The apparatus of claim 10 in which the at least one processor is further configured to determine a set of received powers by calculating a set of power profiles.