Method and system for frame timing acquisition in evolved universal terrestrial radio access (EUTRA)

• US 8,583,155 B2
• Filed: 04/30/2012
• Issued: 11/12/2013
• Est. Priority Date: 09/12/2008
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Swarts, Francis, Kent, Mark
• Primary Examiner(s): Nguyen, Hai V
• Application Number:
  US13/460,144
• Publication Number:
  US 20120275379A1
• Time in Patent Office: 561 Days
• Field of Search: 455/502
• US Class Current: 455/502
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

Aspects of a method and system for frame timing acquisition in evolved universal terrestrial radio access (EUTRA) may include determining a received secondary synchronization sequence (SSS) based on a selected cyclic prefix length and on synchronization of a primary synchronization sequence (PSS). A first portion of information associated with the received SSS may be processed separately from a second portion of information associated with the received SSS. A frame timing and/or base station identifier may be determined by comparing the processed first portion of information with the processed second portion of information. The cyclic prefix length may be selected from a finite set of possible cyclic prefix lengths. The cyclic prefix length may be, for example, 9 samples or 32 samples. The primary synchronization sequence synchronization may be determined via correlation.

Claims

1. An apparatus, comprising:

a processor configured to process a first portion of information and a second portion of information, the first and second portions of information containing a first and a second secondary synchronization signal (SSS), respectively, based on subcarrier positions of the first and second SSSs, wherein the first and second portions of information are included in a first and a second sub-frame, respectively, from among a plurality of first and second sub-frames;

wherein the processor is further configured to combine the first and second portions of information from each of the plurality of first and second sub-frames to provide a first and a second set of detected information corresponding to a selected cyclic prefix (CP) length; and

a decision module configured to determine a network statistic based on a comparison between the first and second sets of detected information.

2. The apparatus of claim 1, wherein the first and second SSS are the same SSS, and wherein the processor further comprises:

a shift register buffer configured to store the SSS and a CP according to the selected CP length.

3. The apparatus of claim 2, wherein the processor is further configured to select the SSS from the shift register buffer based on the selected CP length.

4. The apparatus of claim 3, wherein the selected CP length is selected from a set of CP lengths.

5. The apparatus of claim 4, wherein the set of CP lengths comprises:

9 samples; and

32 samples.

6. The apparatus of claim 1, wherein the first and second SSS are the same SSS, wherein the processor is further configured to process a primary synchronization sequence (PSS) to provide a channel estimate, and wherein the first and second sets of detected information are based on the channel estimate and the SSS.

7. The apparatus of claim 1, wherein the first and second SSS are the same SSS, and wherein the network statistic comprises:

a frame timing;

a base station identifier;

SSS information;

or

the SSS.

8. The apparatus of claim 1, wherein the first SSS is interleaved with the second SSS such that the first SSS occupies even subcarrier positions within the first sub-frame and odd subcarrier positions within the second sub-frame, and wherein the second SSS occupies even subcarrier positions within the second sub-frame and odd subcarrier positions within the first sub-frame.

9. The apparatus of claim 8, wherein the processor is further configured to scramble the first and second SSSs that occupy even subcarrier positions once, and to scramble the first and second SSSs that occupy odd subcarrier positions twice.

10. The apparatus of claim 1, wherein the plurality of first and second sub-frames constitute a plurality of consecutive data frames.

11. In a wireless device, a method for processing communication signals, comprising:

receiving a first portion of information and a second portion of information from among a plurality of information, the first and second portions of information containing a first and a second secondary synchronization signal (SSS), respectively, and being included in a first and a second sub-frame, respectively, from among a plurality of first and second sub-frames;

selecting a cyclic prefix (CP) length from among a set of CP lengths;

combining the first and the second portions of information from the plurality of first and second sub-frames to provide a first and a second set of detected information corresponding to the CP length;

extracting the first and second SSS from the first and second sets of detected information, respectively, based on the CP length; and

comparing the first SSS and the second SSS to determine a consistency between them and to verify they have been properly decoded.

12. The method of claim 11, wherein the plurality of first and second sub-frames constitute a plurality of consecutive data frames.

13. The method of claim 12, wherein the plurality of first and second sub-frames include information associated with even and odd sub-carrier positions, the method further comprising:

processing separately a part of the plurality of first sub-frames associated with odd sub-carrier positions from a part of the plurality of first sub-frames associated with even sub-carrier positions.

14. The method of claim 12, wherein the plurality of first and second sub-frames include information associated with even and odd sub-carrier positions, the method further comprising:

processing separately a part of the plurality of second sub-frames associated with odd sub-carrier positions from a part of the second sub-frames associated with even sub-carrier positions.

15. The method of claim 11, wherein the first SSS is interleaved with the second SSS such that the first SSS occupies even subcarrier positions within the first sub-frame and odd subcarrier positions within the second sub-frame, and wherein the second SSS occupies even subcarrier positions within the second sub-frame and odd subcarrier positions within the first sub-frame.

16. The method of claim 15, further comprising:

scrambling the first and second SSSs which occupy even subcarrier positions once; and

scrambling the first and second SSSs which occupy odd subcarrier positions twice.

17. In a wireless device, a method for processing communication signals, comprising:

selecting a cyclic prefix (CP) length from among a set of CP lengths;

processing separately a first portion of information associated with a received first secondary synchronization sequence (SSS) and a second portion of information associated with a received second SSS based on corresponding sub-carrier positions of the first and second SSSs, the first and second portions of the information being included in a first and a second sub-frame, respectively, from among a plurality of first and second sub-frames;

combining the first and second portions of information from the plurality of first and second sub-frames to provide a first set of processed information and a second set of processed information, respectively;

comparing the first set of processed information and the second set of processed information to evaluate a consistency of decoded information obtained from the first and second sets of processed information based on the selected CP length; and

determining a wireless network statistic based on the decoded information.

18. The method of claim 17, wherein the selecting comprises:

selecting a CP length of 9 samples or 32 samples.

19. The method of claim 17, further comprising:

determining a synchronization of a primary synchronization sequence (PSS) included in the plurality of first and second sub-frames via a correlation sequence detection algorithm.

20. The method of claim 17, further comprising:

determining a synchronization of a primary synchronization sequence (PSS) included in the plurality of first and second sub-frames by determining a slot timing and a channel estimate via PSS processing.

21. The method of claim 17, wherein the processing further comprises:

processing separately a part of the first portion of the information associated with an odd sub-carrier position from a part of the first portion of the information that is associated with an even sub-carrier position.

22. The method of claim 17, wherein the processing further comprises:

processing separately a part of the second portion of the information associated with an odd sub-carrier position from a part the second portion of the information that is associated with an even sub-carrier position.

23. The method of claim 17, wherein the first and second SSS are the same SSS, and wherein the determining the wireless network statistic comprises:

determining a frame timing, a base station identifier, SSS information, or the SSS as the wireless network statistic.

24. The method of claim 17, wherein the first SSS is interleaved with the second SSS such that the first SSS occupies even subcarrier positions within the first sub-frame and odd subcarrier positions within the second sub-frame, and wherein the second SSS occupies even subcarrier positions within the second sub-frame and odd subcarrier positions within the first sub-frame.

25. The method of claim 24, further comprising:

scrambling the first and second SSSs that occupy even subcarrier positions once; and

scrambling the first and second SSSs that occupy odd subcarrier positions twice.

26. The method of claim 17, wherein the plurality of first and second sub-frames constitute a plurality of consecutive data frames.