Phase sequences for timing and access signals

• US 6,804,191 B2
• Filed: 04/04/2003
• Issued: 10/12/2004
• Est. Priority Date: 04/05/2002
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Flarion Technologies (Qualcomm, Inc.)
• Inventors: Richardson, Tom
• Primary Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US10/407,016
• Publication Number:
  US 20030189893A1
• Time in Patent Office: 557 Days
• Field of Search: 370/208, 370/203, 370/204, 370/206, 370/207, 370/210, 370/328, 370/329, 370/330, 370/336, 370/343, 370/344, 370/436, 370/480, 370/481, 370/482, 370/483, 370/503, 370/516, 370/519, 370/335, 370/342, 370/441, 370/509, 370/522, 370/236, 370/410, 375/271, 375/279, 375/260, 375/140, 375/347, 375/261
• US Class Current: 370/208
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

Methods and apparatus for splitting Golay sequences into a plurality of subsets of sequence elements and transmitting the subsets are described. The sequence subsets include an equal number of elements, e.g., symbols, from the split sequence and are transmitted using one group of tones per subset. The tones in each group of tones are uniformly spaced with one symbol being transmitted on each tone. The groups of tones are separated from one another by a frequency spacing which is greater, e.g., many times greater, than the frequency spacing between the tones in each group. Low peak to average power ratios are achieved for the transmitted signals while at the same time allowing for a wide band of frequencies to be used to transmit the split sequence. This leads to greater frequency diversity and facilitates frequency and phase related signal measurements by a device receiving the signal.

Claims

1. A communications method, the method comprising:

generating a first set of complex values, the phases of said complex values being a Golay sequence, said first set of complex values being subdivided into a first plurality of subsets, each subset in said first plurality of subsets having the same number of elements; and

transmitting each of said first plurality of subsets using a plurality of uniformly spaced tones, a different group of tones being used to transmit each of said subsets, the tones within each group being separated from one another in frequency by a first amount, each group of tones used for transmitting one of said first plurality of subsets being separated in the frequency domain from the nearest one of said groups of tones used for transmitting one of said first plurality of subsets by a second amount which is greater than said first amount.

2. The communications method of claim 1, wherein said second amount is at least 5 times said first amount.

3. The communications method of claim 1, wherein said second amount is at least 10 times said first amount.

4. The communications method of claim 1,

wherein said first set of complex values includes N values, N being an integer power of 2, and

wherein said first plurality of subsets includes X subsets, where X is equal to a power of 2.

5. The communications method of claim 4, wherein X is 2.

6. The communications method of claim 5, wherein N is 16.

7. The communications method of claim 4, wherein X is 4.

8. The method of claim 1, further comprising:

generating a second set of complex values whose phase constitute a Golay sequence, said second set of complex values being subdivided into a second plurality of subsets, each subset in said second plurality of subsets having the same number of elements; and

transmitting each subset in said second plurality of subsets using a plurality of uniformly spaced tones, a different group of tones being used to transmit each of said subsets, the tones within each group being separated from one another in frequency by a third amount, each group of tones used for transmitting one of said second plurality of subsets being separated in the frequency domain from the nearest one of said groups of tones used for transmitting one of said second plurality of subsets by a fourth amount which is greater than said third amount.

9. The method of claim 8, wherein said third and fourth amount are a function of an intended signal interpretation by a receiver of the second set of complex symbols.

10. The method of claim 9, wherein said third and fourth amounts are different for different types of information which may be represented by said second set of complex symbols, one type of information which may be represented by said second set of complex symbols being an access request.

11. The method of claim 1, further comprising the steps of:

operating a base station to receive a signal including the transmitted subsets of complex values;

operating the base station to generate a time delay estimate from at least a portion of the received signal corresponding to the transmitted subsets of complex values.

12. The method of claim 11, wherein said step of generating a first set of complex values and transmitting each of said first plurality of subsets is performed by a mobile node, the method further comprising:

operating the base station to transmit a timing control signal to said mobile node, said timing control signal being a function of said generated time delay estimate.

13. The method of claim 1, wherein said time delay estimate is a transmission channel time delay estimate corresponding to the time to transmit said plurality of subsets from said mobile node to said base station.

14. A communications method, the method comprising:

generating a first set of complex values, the phases of said complex values being a Golay sequence, said first set of complex values being subdivided into a first plurality of subsets, each subset in said first plurality of subsets having the same number of elements; and

transmitting each of said first plurality of subsets using a plurality of uniformly spaced tones, a different group of tones being used to transmit each of said subsets, the tones within each group being separated from one another in frequency by a first amount, each group of tones used for transmitting one of said first plurality of subsets being separated in the frequency domain from the nearest one of said groups of tones used for transmitting one of said first plurality of subsets by a second amount which is greater than said first amount;

generating a second set of complex values whose phase constitute a Golay sequence, said second set of complex values being subdivided into a second plurality of subsets, each subset in said second plurality of subsets having the same number of elements; and

transmitting each subset in said second plurality of subsets using a plurality of uniformly spaced tones, a different group of tones being used to transmit each of said subsets, the tones within each group being separated from one another in frequency by a third amount, each group of tones used for transmitting one of said second plurality of subsets being separated in the frequency domain from the nearest one of said groups of tones used for transmitting one of said second plurality of subsets by a fourth amount which is greater than said third amount, wherein said third and fourth amount are a function of the time said second set of complex values is transmitted.

15. The method of claim 14, wherein said third and fourth amounts will vary depending on when said second plurality of subsets is transmitted.

16. A communications system, comprising:

a first communications device including;

means for generating a first set of complex values whose phase constitute a Golay sequence, said first set of complex values being subdivided into a first plurality of subsets, each subset in said first plurality of subsets having the same number of elements; and

means for transmitting each of said first plurality of subsets using a plurality of uniformly spaced tones, a different group of tones being used to transmit each of said subsets, the tones within each group being separated from one another in frequency by a first amount, each group of tones used for transmitting one of said first plurality of subsets being separated in the frequency domain from the nearest one of said groups of tones used for transmitting one of said first plurality of subsets by a second amount which is greater than said first amount.

17. The communications system of claim 16,

wherein said first set of complex values includes N values, N being an integer power of 2, and

wherein said first plurality of subsets includes X subsets, where X is equal to a power of 2.

18. The communications system of claim 17, wherein X is 2.

19. The communications system of claim 18, wherein N is 16.

20. The communications system of claim 17, wherein said first communications device is a mobile node, said communication system further comprising:

a base station including;

means for receiving a signal including the transmitted subsets of complex values; and

means for generating a time delay estimate from at least a portion of the received signal corresponding to the transmitted subsets of complex values.

21. The communications system of claim 20, wherein said base station further includes:

means for transmitting timing control signal to said mobile node, said timing control signal being a function of said generated time delay estimate.