Method and apparatus for detecting a boundary of a data frame in a communication network

• US 8,817,771 B1
• Filed: 07/13/2011
• Issued: 08/26/2014
• Est. Priority Date: 07/16/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Zhao, Qing, Shen, Manyuan, Song, Leilei, Lou, Hui-Ling
• Primary Examiner(s): Moore, Jr., Michael J
• Application Number:
  US13/182,004
• Time in Patent Office: 1,140 Days
• Field of Search: 370/350
• US Class Current: 370/350
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 27/2678 using cyclostationarities, e.g. cyclic prefix or postfix

Abstract

In embodiments of frame boundary detection, a data signal that includes a plurality of different synchronization signals is received. Symbol boundaries of orthogonal frequency-division multiplexing (OFDM) symbols are detected in the data signal based on signal characteristics of the OFDM symbols. The characteristics of the OFDM symbols include cyclic shift properties of the OFDM symbols, such as the characteristic that a first portion of an OFDM symbol is the same as a last portion of the OFDM symbol. One or more of the plurality of different synchronization signals in the data signal can be located using the detected symbol boundaries of the OFDM symbols to determine a frame boundary of a data frame in the data signal.

Claims

1. A communication device, comprising:

one or more antennas configured to receive a data signal comprising a plurality of different synchronization signals;

a memory and a processor to implement a frame boundary detection service, wherein the frame boundary detection service is configured to;

detect symbol boundaries of orthogonal frequency-division multiplexing (OFDM) symbols in the data signal based on signal characteristics of the OFDM symbols; and

locate one or more of the plurality of different synchronization signals in the data signal to determine a frame boundary of a data frame in the data signal by;

examining the OFDM symbols using the detected symbol boundaries of the OFDM symbols;

locating a primary synchronization signal in one of the OFDM symbols; and

locating a secondary synchronization signal using a location of the primary synchronization signal.

2. The communication device as recited in claim 1, wherein the signal characteristics of the OFDM symbols comprise cyclic shift properties of the OFDM symbols, at least one of the cyclic shift properties including a first portion of an OFDM symbol being the same as a last portion of the OFDM symbol.

3. The communication device as recited in claim 1, wherein, to locate the one or more of the plurality of different synchronization signals, the frame boundary detection service is further configured to convert the OFDM symbols from a time domain to a frequency domain using a Fast Fourier Transform (FFT).

4. The communication device as recited in claim 1, wherein the frame boundary detection service is further configured to determine and compensate for a fractional carrier frequency offset when detecting the symbol boundaries of the OFDM symbols.

5. The communication device as recited in claim 1, wherein the frame boundary detection service is further configured to locate the one or more of the plurality of different synchronization signals by:

locating a second secondary synchronization signal of a pair of secondary synchronization signals using the location of the located secondary synchronization signal, the located secondary synchronization signal being the first secondary synchronization signal of the pair of secondary synchronization signals in one of the OFDM symbols.

6. The communication device as recited in claim 1, wherein the located one or more of the plurality of different synchronization signals comprise secondary synchronization signals of a long term evolution (LTE) data signal, and wherein the frame boundary detection service is further configured to determine the frame boundary of the LTE data frame based on the location of the secondary synchronization signals and a frame structure of an LTE data frame.

7. A method, comprising:

receiving a long term evolution (LTE) data signal;

detecting symbol boundaries of orthogonal frequency-division multiplexing (OFDM) symbols in the LTE data signal based on signal characteristics of the OFDM symbols; and

locating one or more of a plurality of different synchronization signals in the LTE data signal using the detected symbol boundaries of the OFDM symbols to determine a frame boundary of an LTE data frame in the LTE data signal by;

examining the OFDM symbols using the detected symbol boundaries of the OFDM symbols;

locating a secondary synchronization signal in one of the OFDM symbols; and

locating a primary synchronization signal using a location of the secondary synchronization signal.

8. The method as recited in claim 7, wherein the signal characteristics of the OFDM symbols comprise cyclic shift properties of the OFDM symbols, and wherein at least one of the cyclic shift properties includes a first portion of an OFDM symbol being the same as a last portion of the OFDM symbol.

9. The method as recited in claim 7, wherein locating the secondary synchronization signal comprises:

converting the OFDM symbols from a time domain to a frequency domain using a Fast Fourier Transform (FFT).

10. The method as recited in claim 7, further comprising compensating for a fractional carrier frequency offset (CFO) when detecting the symbol boundaries of the OFDM symbols.

11. The method as recited in claim 7, wherein locating the secondary synchronization signal further comprises:

locating a second secondary synchronization signal of a pair of secondary synchronization signals using the location of the located secondary synchronization signal, the located secondary synchronization signal being the first secondary synchronization signal of the pair of secondary synchronization signals in one of the OFDM symbols.

12. The method as recited in claim 7, further comprising determining the boundary of an LTE data frame based on the location of the secondary synchronization signal and a frame structure of the LTE data frame.

13. A system-on-chip, comprising:

an LTE signal receiver configured to receive a long term evolution (LTE) data signal;

a frame boundary detection service that is programmed to;

detect symbol boundaries of orthogonal frequency-division multiplexing (OFDM) symbols in the LTE data signal based on signal characteristics of the OFDM symbols; and

locate one or more of a plurality of different synchronization signals in the LTE data signal using the detected symbol boundaries of the OFDM symbols to determine a frame boundary of an LTE data frame in the LTE data signal by;

examining the OFDM symbols using the detected symbol boundaries of the OFDM symbols;

locating one of either a primary synchronization signal or a secondary synchronization signal of a pair of secondary synchronization signals in one of the OFDM symbols; and

based on said locating, locating the other of the primary synchronization signal and the secondary synchronization signal of the pair of secondary synchronization signals.

14. The system-on-chip as recited in claim 13, wherein the signal characteristics of the OFDM symbols comprise cyclic shift properties of the OFDM symbols, and wherein at least one of the cyclic shift properties includes a first portion of an OFDM symbol being the same as a last portion of the OFDM symbol.

15. The system-on-chip as recited in claim 13, wherein the frame boundary detection service is further programmed to determine and compensate for a fractional carrier frequency offset (CFO) when the symbol boundaries of the OFDM symbols are detected.

16. The system-on-chip as recited in claim 13, wherein the frame boundary detection service is further programmed to locate the secondary synchronization signal by:

locating a second secondary synchronization signal of the pair of secondary synchronization signals using the location of the located secondary synchronization signal of the pair of secondary synchronization signals in one of the OFDM symbols.

17. The system-on-chip as recited in claim 13, wherein the frame boundary detection service is further programmed to determine the frame boundary of the LTE data frame based on the location of the secondary synchronization signal and a frame structure of the LTE data frame.

18. The system-on-chip as recited in claim 13, wherein, to locate the one or more of the plurality of different synchronization signals, the frame boundary detection service is further configured to convert the OFDM symbols from a time domain to a frequency domain using a Fast Fourier Transform (FFT).

19. The system-on-chip as recited in claim 13, wherein the first located synchronization signal is the primary synchronization signal.

20. The system-on-chip as recited in claim 13, wherein the first located synchronization signal is one of the pair of secondary synchronization signals.