Systems and methods for compensating a channel estimate for phase and sampling phase jitter

• US 9,432,276 B1
• Filed: 10/30/2015
• Issued: 08/30/2016
• Est. Priority Date: 02/13/2002
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Narasimhan, Ravi
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US14/927,982
• Time in Patent Office: 305 Days
• Field of Search: 375/260, 375/316, 375/326, 375/355
• US Class Current: 1/1
• CPC Class Codes: H03L 7/091 the phase or frequency detector using a sampling device H03L7/087 takes precedence
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/024 channel estimation algorithms
• CPC Class Codes: H04L 27/2602 Signal structure
• 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 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 7/0016 correction of synchronization errors

Abstract

A system including a circuit to compensate for sampling phase jitter. The system includes a channel estimator to determine, based on training symbols in a preamble of a data packet received via a communication channel, an estimate of the communication channel and a carrier frequency associated with the communication channel. The circuit compensates, based on the determined carrier frequency, a phase of the estimate of the communication channel to adjust for a carrier frequency offset associated with the communication channel, and, based on a data rate at which the data packet was received via the communication channel, selectively compensates the estimate of the communication channel for sampling phase jitter.

Claims

1. A system, comprising:

a channel estimator to determine, based on training symbols in a preamble of a data packet received via a communication channel, (i) an estimate of the communication channel and (ii) a carrier frequency associated with the communication channel; and

a circuit to (i) compensate, based on the determined carrier frequency, a phase of the estimate of the communication channel to adjust for a carrier frequency offset associated with the communication channel, and (ii) based on a data rate at which the data packet was received via the communication channel, selectively compensate the estimate of the communication channel for sampling phase jitter.

2. The system of claim 1, wherein the training symbols include (i) a short training symbol associated with coarse estimation of the carrier frequency and the estimate of the communication channel and (ii) a long training symbol associated with fine estimation of the carrier frequency and the estimate of the communication channel.

3. The system of claim 1, wherein, to selectively compensate the estimate of the communication channel for sampling phase jitter, the circuit is further to (i) determine the data rate at which the data packet was received via the communication channel, and (ii) selectively compensate the estimate of the communication channel for sampling phase jitter based on a comparison between the data rate at which the data packet was received via the communication channel and a threshold.

4. The system of claim 3, wherein the threshold is 54 megabits per second (Mbps).

5. The system of claim 3, wherein the circuit is further to compensate the estimate of the communication channel for sampling phase jitter if the data rate at which the data packet was received via the communication channel is greater than the threshold.

6. The system of claim 3, wherein the circuit is further to not compensate the estimate of the communication channel for sampling phase jitter if the data rate at which the data packet was received via the communication channel is less than or equal to the threshold.

7. The system of claim 1, wherein the data packet includes, in a signal field following the preamble, an orthogonal frequency division multiplexing symbol.

8. The system of claim 7, wherein, to selectively compensate for the sampling phase jitter, the circuit is further to determine a compensation factor for each of a plurality of subcarriers associated with the orthogonal frequency division multiplexing symbol.

9. The system of claim 8, wherein, to calculate the compensation factor, the circuit is further to calculate the compensation factor based on pilot signals placed within predetermined subcarriers of the plurality of subcarriers.

10. The system of claim 8, wherein the compensation factor comprises an affine complex number having a nonzero imaginary component.

11. The system of claim 8, wherein the compensation factor has a first term and a second term, wherein the first term varies linearly with respect to an index of the plurality of subcarriers, and wherein the second term is a constant term.

12. The system of claim 11, wherein the second term is associated with (i) phase noise and (ii) the carrier frequency offset associated with the communication channel.

13. A method, comprising:

determining, based on training symbols in a preamble of a data packet received via a communication channel, (i) an estimate of the communication channel and (ii) a carrier frequency associated with the communication channel;

compensating, based on the determined carrier frequency, a phase of the estimate of the communication channel to adjust for a carrier frequency offset associated with the communication channel; and

based on a data rate at which the data packet was received via the communication channel, selectively compensating the estimate of the communication channel for sampling phase jitter.

14. The method of claim 13, wherein selectively compensating the estimate of the communication channel for sampling phase jitter includes (i) determining the data rate at which the data packet was received via the communication channel, and (ii) selectively compensating the estimate of the communication channel for sampling phase jitter based on a comparison between the data rate at which the data packet was received via the communication channel and a threshold.

15. The method of claim 14, wherein the threshold is 54 megabits per second (Mbps).

16. The method of claim 14, wherein selectively compensating the estimate includes (i) compensating the estimate of the communication channel for sampling phase jitter if the data rate at which the data packet was received via the communication channel is greater than the threshold and (ii) not compensating the estimate of the communication channel for sampling phase jitter if the data rate at which the data packet was received via the communication channel is less than or equal to the threshold.

17. The method of claim 13, wherein selectively compensating for the sampling phase jitter includes determining a compensation factor for each of a plurality of subcarriers associated with an orthogonal frequency division multiplexing symbol.

18. The method of claim 17, wherein calculating the compensation factor includes calculating the compensation factor based on pilot signals placed within predetermined subcarriers of the plurality of subcarriers.

19. The method of claim 17, wherein the compensation factor comprises an affine complex number having a nonzero imaginary component.

20. The method of claim 17, wherein the compensation factor has a first term and a second term, wherein the first term varies linearly with respect to an index of the plurality of subcarriers, and wherein the second term is a constant term, and wherein the second term is associated with (i) phase noise and (ii) the carrier frequency offset associated with the communication channel.