Training sequence for channel estimation in a data transmission system

• US 20050276338A1
• Filed: 06/09/2004
• Published: 12/15/2005
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: Matthew Leung, Pak Hei, Nedic, Slobodan, Tang, Eugene Yuk-Yin, Chow, Jacky S., Luk, King-Fuk
• Granted Patent: US 7,697,619 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

An improved training sequence for estimating a channel (e.g., channel impulse response) in the time domain is disclosed. The improved training sequence enables time-domain estimation and eliminates the need for correct frequency-domain channel estimation at every frequency. By utilizing the training sequence according to the invention, estimation of each of a plurality of time-domain channel taps can be decoupled from each other. This enables a channel estimate to be performed with not only a higher convergence speed but also lower complexity.

Claims

1. A training sequence for use in producing a channel estimate at a receiver of a data transmission system, wherein a series of blocks of training samples of said training sequence are transmitted over a wire to the receiver,

wherein, for a given pair of the blocks of training samples, all samples in the given pair of the blocks of training samples are identical except for one particular sample that is different.

2. A training sequence as recited in claim 1, wherein the series of the blocks of training samples are all time-domain training samples.

3. A training sequence as recited in claim 1, wherein the training samples are generated and transmitted from a transmitter of the data transmission system.

4. A training sequence as recited in claim 3, wherein the data transmission system is a multicarrier data transmission system.

5. A training sequence as recited in claim 4, wherein the multicarrier data transmission system is digital subscriber line system.

6. A training sequence as recited in claim 1, wherein at least the training samples that are identical in the given pairs of blocks have at least a pseudo-random characteristic.

7. A training sequence as recited in claim 1, wherein at least the training samples that are identical in the given pairs of blocks are generated in at least a pseudo-random manner.

8. A training sequence as recited in claim 1, wherein the blocks of the training samples include at least one of a cyclic prefix and a cyclic suffix.

9. A training sequence as recited in claim 1, wherein each of the blocks of the training samples include N samples, and wherein the channel estimate is done using M taps, where N is greater than 2M.

10. A training sequence as recited in claim 9, wherein the position of the one particular sample within the blocks of the training symbols is after the (M−

1)th sample but before the (N−

M+1)th sample.

11. A training sequence as recited in claim 10, wherein the series of the blocks of training samples are all time-domain training samples.

12. A training sequence as recited in claim 11, wherein the data transmission system is a multicarrier data transmission system.

13. A training sequence as recited in claim 12, wherein the multicarrier data transmission system is digital subscriber line system.

14. A training sequence as recited in claim 13, wherein the training samples are generated and transmitted from a transmitter of the multicarrier data transmission system.

15. A training sequence as recited in claim 10, wherein at least the training samples that are identical in the given pairs of blocks have at least a pseudo-random characteristic.

16. A training sequence for use in producing a channel estimate at a receiver of a data transmission system, wherein a series of blocks of training samples of said training sequence are transmitted over a wire to the receiver,

wherein, for a given group of the training samples, all the training samples in the given group are periodic with a periodicity of T, except for one of the training samples within the given group, where T is greater than or equal to the number of taps of the channel estimate.

17. A training sequence as recited in claim 16, wherein the given group has a length of at least 3T.

18. A training sequence as recited in claim 17, wherein the one of the training samples being different in the given group is positioned either (T−

1) samples after the start of the given group and (2T−

1) samples before the end of the given group or (2T−

1) samples after the start of the group and (T−

1) samples before the end of the given group.

19. A training sequence as recited in claim 16, wherein the data transmission system is a multicarrier data transmission system.

20. A training sequence as recited in claim 19, wherein the multicarrier data transmission system is digital subscriber line system.

21. A training sequence as recited in claim 16, wherein those of the training samples in the group that are periodic have at least a pseudo-random characteristic.

22. A method for transmitting a training sequence for use in a multicarrier data transmission system to produce a channel estimate, said method comprising:

(a) obtaining a training sequence, the training sequence including a plurality of blocks of samples;

(b) selecting a first block of the blocks of samples from the training sequence;

(c) transmitting the first block;

(d) modifying the first block such that only one of the samples of the samples within the first block is changed;

(e) saving the modified first block into a buffer;

(f) selecting either a new block of the blocks of samples from the training sequence if not all of the training sequence has been transmitted, or a block of the blocks of samples from the buffer that stores modified blocks if that buffer is not empty;

(g) transmitting the selected block;

(h) if the selected block is a new block of the blocks of samples from the training sequence, modifying the selected block such that the sample at the same location as in the modified first block is changed; and

(i) saving the modified selected block following said modifying (h) when the selected block is a new block.

23. A method as recited in claim 22, wherein said method further comprises:

(j) repeating said selecting (f) through said saving (i) until all the blocks of samples from the training sequence are transmitted.

24. A method for transmitting a training sequence for use in a multicarrier data transmission system to produce a channel estimate, said method comprising:

(a) obtaining a training sequence, the training sequence including a plurality of blocks of samples;

(b) selecting a first block of the blocks of samples from the training sequence;

(c) transmitting the first block;

(d) modifying the first block such that only one of the samples of the samples within the first block is changed;

(e) transmitting the modified first block;

(f) selecting a next block of the blocks of samples from the training sequence;

(g) transmitting the next block;

(h) modifying the next block such that only one of the samples of the samples within the next block is changed; and

(i) transmitting the modified next block.

25. A method as recited in claim 24, wherein the samples are time-domain samples.

26. A method as recited in claim 25, wherein the training sequence is at least pseudo-random.

27. A method as recited in claim 24, wherein said method further comprises:

(j) repeating said selecting (f) through said transmitting (i) until all the blocks of samples from the training sequence are transmitted.

28. A method for transmitting a training sequence for use in a multicarrier data transmission system to produce a channel estimate, said method comprising:

(a) obtaining a group of samples from a training sequence, the group of samples being periodic with a period of T, except for one sample, the number of samples in the group being at least 3T; and

(b) transmitting the group of samples.

29. A method as recited in claim 28, wherein those of the training samples in the group that are periodic have at least a pseudo-random characteristic.

30. A computer readable medium including at least computer program code for transmitting a training sequence for use in a data transmission system to produce a channel estimate, said computer readable medium comprising:

computer program code for obtaining a training sequence, the training sequence including a plurality of blocks of samples;

computer program code for selecting a first block of the blocks of samples from the training sequence;

computer program code for transmitting the first block;

computer program code for modifying the first block such that only one of the samples of the samples within the first block is changed;

computer program code for transmitting the modified first block;

computer program code for selecting a second block of the blocks of samples from the training sequence;

computer program code for transmitting the second block;

computer program code for modifying the second block such that the sample at the same location in the second block as the modified one of the samples within the first block is changed; and

computer program code for transmitting the modified second block.

31. A computer readable medium as recited in claim 30, wherein the training sequence is at least pseudo-random.

32. A computer readable medium as recited in claim 31, wherein the samples are time-domain samples.

33. A computer readable medium including at least computer program code for transmitting a training sequence for use in a data transmission system to produce a channel estimate, said method comprising:

computer program code for obtaining a group of samples from a training sequence, the group of samples being periodic with a period of T, except for one sample, the number of samples in the group being at least 3T; and

computer program code for transmitting the group of samples.

34. A computer readable medium as recited in claim 33, wherein those of the training samples in the group that are periodic have at least a pseudo-random characteristic.