Method and system for determining symbol boundary timing in a multicarrier data transmission system

• US 8,817,919 B1
• Filed: 09/10/2012
• Issued: 08/26/2014
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Chow, Jacky S., Leung, Pak Hei Matthew, Luk, King-Fuk, Sands, Nicholas Philip, Tang, Eugene Yuk-Yin
• Primary Examiner(s): Ahn, Sam K
• Assistant Examiner(s): Wong, Linda
• Application Number:
  US13/608,011
• Time in Patent Office: 715 Days
• Field of Search: 375/130, 375/136, 375/135, 375/146, 375/147, 375/140, 375/219, 37524026-24028, 375/260, 375/284, 375/285, 375/295, 375/316, 375/340, 375/343, 375/342, 375346-349, 375/354, 375/355, 375/363, 375/364, 375/211, 375/220, 375/221, 375/222, 37524002-24007, 375229-236, 375/261, 375/271, 375/268, 375/298, 375/300, 375/302, 375/308, 375/320, 375/322, 375/326, 375/329, 375/338, 375/341, 375/324, 375/362, 375/371
• US Class Current: 375/342
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04L 27/2691 involving interference determination or cancellation

Abstract

Improved techniques for acquiring symbol boundary timing at a receiver of a multicarrier data transmission system during a training sequence are disclosed. One aspect is symbol boundary determination at a receiver wherein minimal interference is used as a criterion in selecting from a plurality of potential symbol boundary timings. The symbol boundary determination at the receiver can be performed in a time domain or a frequency domain manner. Another aspect pertains to an improved training sequence wherein pairs of identical symbols are transmitted by a transmitter. These symbols can be supplied to the transmitter in a time domain or a frequency domain manner.

Claims

1. A symbol timing unit for selecting a symbol timing boundary, the symbol timing unit comprising:

an estimator configured to generate a magnitude of noise due to inter-carrier and inter-symbol interference for a plurality of different potential symbol timing boundaries based on difference values between transmitted symbols; and

a selector configured to select one of the plurality of different potential symbol timing boundaries based on the magnitude of the noise due to inter-carrier and inter-symbol interference.

2. A symbol timing unit as recited in claim 1, wherein the magnitude of the noise due to inter-carrier and inter-symbol interference of the selected one of the plurality of different potential symbol timing boundaries is lower than the magnitude of the noise due to inter-carrier and inter-symbol interference of other ones of the plurality of different potential symbol timing boundaries.

3. A symbol timing unit as recited in claim 1, wherein the symbol timing unit further comprises a buffer configured to receive a training sequence, wherein the training sequence is organized such that a first training symbol and a second training symbol are preceded or succeeded by different symbols.

4. A symbol timing unit as recited in claim 3, wherein the symbol timing unit further comprises a subtractor configured to calculate one of the difference values based at least in part on a subtraction of the first training symbol from the second training symbol.

5. A symbol timing unit as recited in claim 4, wherein the symbol timing unit further comprises an accumulator configured to accumulate the one of the difference values with a previously computed difference value.

6. A symbol timing unit as recited in claim 3, wherein the first training symbol and the second training symbol are received in pairs.

7. A symbol timing unit as recited in claim 4, wherein the symbol timing unit further comprises a controller configured to repeat the subtraction over at most a factor of a symbol length.

8. A symbol timing unit as recited in claim 3, wherein the first training symbol and the second training symbol have random or pseudo-random characteristics.

9. A method for selecting a symbol timing boundary, the method comprising:

estimating a magnitude of noise due to inter-carrier and inter-symbol interference for a plurality of different potential symbol timing boundaries based on difference values between transmitted symbols; and

selecting one of the plurality of different potential symbol timing boundaries based on the estimated magnitude of the noise due to inter-carrier and inter-symbol interference.

10. A method as recited in claim 9, wherein the magnitude of the noise due to inter-carrier and inter-symbol interference of the selected one of the plurality of different potential symbol timing boundaries is lower than the magnitude of the noise due to inter-carrier and inter-symbol interference of other ones of the plurality of different potential symbol timing boundaries.

11. A method as recited in claim 9, further comprising receiving a training sequence wherein the training sequence is organized such that a first training symbol and a second training symbol are preceded or succeeded by different symbols.

12. A method as recited in claim 11 further comprising calculating one of the difference values based at least in part on a subtraction of the first training symbol from the second training symbol.

13. A method as recited in claim 12 further comprising accumulating the one of the difference values with a previously computed difference value.

14. A method as recited in claim 11, wherein the first training symbol and the second training symbol are received in pairs.

15. A method as recited in claim 12 further comprising repeating the subtraction over at most a factor of a symbol length.

16. A method as recited in claim 11, wherein the first training symbol and the second training symbol have random or pseudo-random characteristics.

17. A system for selecting a symbol timing boundary, the system comprising:

a processor configured to;

estimate a magnitude of noise due to inter-carrier and inter-symbol interference for a plurality of different potential symbol timing boundaries based on difference values between transmitted symbols; and

select one of the plurality of different potential symbol timing boundaries based on the estimated magnitude of the noise due to inter-carrier and inter-symbol interference.

18. A system as recited in claim 17, wherein the magnitude of the noise due to inter-carrier and inter-symbol interference of the selected one of the plurality of different potential symbol timing boundaries is lower than the magnitude of the noise due to inter-carrier and inter-symbol interference of other ones of the plurality of different potential symbol timing boundaries.

19. A system as recited in claim 17, wherein the processor is configured to receive a training sequence, wherein the training sequence is organized such that a first training symbol and a second training symbol are preceded or succeeded by different symbols.

20. A system as recited in claim 19, wherein the processor is configured to calculate one of the difference values based at least in part on a subtraction of the first training symbol from the second training symbol.