Frequency and time synchronization in severe delay spread channels

• US 6,680,932 B1
• Filed: 03/10/2000
• Issued: 01/20/2004
• Est. Priority Date: 03/10/2000
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Hsuan, Yi, Monsen, Peter Thomas
• Primary Examiner(s): Vanderpuye, Kenneth
• Assistant Examiner(s): Phunkulh, Bob A.
• Application Number:
  US09/523,363
• Time in Patent Office: 1,411 Days
• Field of Search: 370/345, 370/350, 370/503, 370/509, 370/510, 370/511, 370/512, 370/516, 370/517, 370/518, 375/226, 375/326, 375/354, 375/362, 375/364, 375/366, 375/367, 375/371
• US Class Current: 370/350
• CPC Class Codes: H04L 2027/0034 using hypothesis testing
• CPC Class Codes: H04L 7/042 Detectors therefor, e.g. correlators, state machines digital correlators in general G06F17/15
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

A method for synchronizing the time and frequency of an incoming packet of transmitted information with a receiver in a wireless communication system includes a synchronization method which may reduce the adverse effects of delay spread introduced by a bad channel. The method includes assigning a plurality of samples in a received synchronization segment of an incoming packet to corresponding bins, determining a number of phase test failures in each bin, and selecting the bin having the fewest number of phase test failures and the fewest number of small samples for synchronizing the time of the incoming packet with the receiver. Additionally, the method calculates the phase drift for the selected bin so that the frequency of the incoming packet is synchronized with that of the receiver.

Claims

1. A method of synchronizing a transmitted packet with a receiver in a wireless communication system, comprising:

assigning a plurality of samples in a received synchronization segment of an incoming packet to corresponding bins;

determining the number of phase test failures in each bin; and

selecting the bin having the fewest number of phase test failures for synchronizing the time and frequency of the incoming packet with the receiver.

2. The method of claim 1, wherein per-symbol phase drift of said selected bin is determined for synchronizing the frequency of the incoming packet with the receiver.

3. The method of claim 2, wherein, if more than one bin has an equal number of fewest phase test failures, the bin selected for time and frequency synchronization is that bin out of those having the fewest number of phase test failures which has the largest minimum eye opening.

4. The method of claim 3, wherein the minimum eye opening is the amplitude of a sample stored in a corresponding bin.

5. The method of claim 2, wherein said step of selecting a bin is defined by the equations:

6. The method of claim 5, wherein per-symbol phase drift (pd) for said selected bin k is defined by:

7. The method of claim 1, wherein small samples are excluded from said time and frequency synchronization, and

wherein a small sample is defined as a category (2) time sample having an amplitude <

0.3.

8. The method of claim 7, wherein said step of selecting a bin is defined by the equations:

9. The method of claim 8, further comprising determining per-symbol phase drift (pd) of said selected bin k for synchronizing frequency of the incoming packet with the receiver, wherein said step of determining is defined by the equation:

10. A synchronizer for use in a receiver of a wireless communication system, comprising:

a time synchronizing unit configured to assign a plurality of samples of an incoming packet to corresponding bins, to determine a number of phase test failures in each bin, and to select the bin having the fewest number of phase test failures for synchronizing time of the incoming packet with the receiver; and

a frequency synchronizing unit for synchronizing the frequency of the incoming transmitted packet of information with that of the receiver.

11. The synchronizer of claim 10, wherein said frequency synchronizing unit is configured to calculate per-symbol phase drift of the selected bin for synchronizing frequency of the incoming packet with the receiver.

12. The synchronizer of claim 10, wherein, in the case where more than one bin has an equal number of fewest phase test failures, the time synchronizing unit checks the minimum eye opening of each bin, selecting that bin having the largest minimum eye opening as the selected bin for time and frequency synchronization.

13. The synchronizer of claim 12, wherein the minimum eye opening is the amplitude of a sample stored in a corresponding bin.

14. The synchronizer of claim 10, wherein the time synchronizing unit selects the bin (k) for time synchronization, and wherein

  k=min_i PTF(i), and

15. The synchronizer of claim 14, wherein the frequency synchronizing unit calculates per-symbol phase drift (pd), wherein

16. The synchronizer of claim 10, wherein small samples of the incoming packet are not processed by the time and frequency synchronization units, a small sample defined as a category (2) time sample having an amplitude <

0.3.

17. The synchronizer of claim 16, wherein the time synchronizing unit selects bin k for time synchronization, and wherein

18. The synchronizer of claim 17, wherein the frequency synchronizing unit determines per-symbol phase drift (pd) for synchronizing frequency of the incoming packet with the receiver by