Beacon signaling in a wireless system

• US 6,985,498 B2
• Filed: 08/13/2003
• Issued: 01/10/2006
• Est. Priority Date: 08/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Flarion Technologies (Qualcomm, Inc.)
• Inventors: Laroia, Rajiv, Li, Junyi, Lane, Frank A.
• Primary Examiner(s): Pezzlo, John
• Assistant Examiner(s): Mills, Donald L.
• Application Number:
  US10/641,399
• Publication Number:
  US 20040095902A1
• Time in Patent Office: 881 Days
• Field of Search: 455/500, 455/507, 455/509, 455/513, 370/335, 370/337, 370/344, 370/430, 370/442, 370/480, 370/481, 370/482, 370/478, 370/527, 375220-222
• US Class Current: 370/478
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A few high power tones used for synchronization and/or other purposes are transmitted in a FDM system during a period of time, e.g., a symbol transmission time period. During normal data transmission symbol periods signals are transmitted using at least 10 tones, e.g., per symbol time. Less than 5 high power signals are transmitted in a symbol time with at least 80% the maximum total transmitter power transmitted being allocated to the high power signals where the maximum total transmitter power is determined from a period of time which may includes one or more data and/or high power tone transmission periods. When the high power tones are transmitted at most 20% of transmitter power is available for transmitting other tones with the power normally being distributed among multiple tones. Normally some tones which would be transmitted in a symbol time go unused during transmission of the high power signals.

Claims

1. A method of operating a base station transmitter in a frequency division multiplexed communications system the base station transmitter using a set of N tones to communicate information over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10, a plurality of tones in said set of N tones being used in parallel to communicate information for at least a portion of said first period of time;

the method comprising;

transmitting during a second period of time a second signal including a set of X tones, the X tones in said set of X tones being used at the same time during said second period of time, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period which occurs during said first period of time, is allocated to said set of X tones during said second period of time.

2. The method of claim 1, wherein said first period of time is at least 30 minutes.

3. The method of claim 1, where X is equal to one.

4. The method of claim 1, wherein at least half of the N-X tones which are in said set of N tones but not in said set of X tones go unused during said second period of time, said second period of time being a symbol transmission time period.

5. The method of claim 4, wherein none of the N-X tones in said set of N tones but not in said set of X tones are used during said second period of time.

6. The method of claim 4, wherein multiple ones of the N-X tones in said set of N tones but not in said set of X tones are used during said second period of time.

7. The method of claim 1, wherein said communications system is an orthogonal frequency division multiplexed system and wherein said second period of time is a period of time used to transmit an orthogonal frequency division multiplexed symbol.

8. The method of claim 7, wherein said second period of time periodically repeats during said first period of time.

12. The method of claim 7,

wherein at least one of said X tones is transmitted at predetermined fixed frequency;

and

wherein said at least one of said X tones is transmitted using a frequency having a fixed frequency offset≧

0 from the lowest frequency tone in said set of N tones.

13. The method of claim 7, wherein at least one of said X tones is transmitted at a frequency which is determined as a function of at least one of a base station identifier and a sector identifier.

9. A method of operating a base station transmitter in an orthogonal frequency division multiplexed communications system the base station transmitter using a set of N tones to communicate information over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10, the method comprising:

transmitting during a second period of time a second signal including a set of X tones, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time is allocated to said set of X tones during said second period of time, said second period of time being a period of time used to transmit an orthogonal frequency division multiplexed symbol; and

transmitting during a third period of time a third signal including a set of Y tones, where Y≦

N, each tone in said third set of Y tones having 20% or less of said maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time, said third period of time having the same duration as said second period of time.

10. The method claim 9, wherein said third period of time and said second period of time overlap, the method further comprising:

modulating at least two of data, control and pilot signals on at least some of said set of Y tones.

11. The method of claim 9, wherein said third period, of time and said second period of time are disjoint, the method further comprising:

modulating at least two of data, control arid pilot signals on at least some of said set of Y tones.

14. The method of claim 9, wherein for each repetition of said second period of time in said first period of time there are at least Z repetitions of said third period of time in said first period of time where Z is at least 10.

15. The method of claim 14, wherein Z is at least 400.

16. A method of operating a base station transmitter in an orthogonal frequency division multiplexed communications system the base station transmitter using a set of N tones to communicate information over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10, the method comprising:

transmitting during a second period of time a second signal including a set of X tones, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time is allocated to said set of X tones during said second period of time, said second period of time being a period of time used to transmit an orthogonal frequency division multiplexed symbol; and

transmitting during a third period of time a third signal including G tones, where G is less than 5, and where at least 80% of said maximum average total base station transmitter power used by said base station transmitter during any 1 second period during said first period of time is allocated to said G tones.

17. The method of claim 16,

wherein the frequency of at least one of said G tones is a function of at least one of a base station identifier and a sector identifier, and

wherein said at least one of said G tones is not one of said set of X tones.

18. The method of claim 17, wherein said second and third periods of time periodically repeat during said first period of time.

19. A base station for use in a frequency division multiplexed communications system the base station, the base station comprising:

a transmitter that uses a set of N tones to communicate information;

first control means coupled to said transmitter, for controlling the transmitter to transmit over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10 and where a plurality of said N tones are used in parallel during at least a portion of said first period of time; and

second control means coupled to said transmitter for controlling the transmitter to transmit during a second period of time a second signal including a set of X tones which are transmitted at the same time, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time is allocated to said set of X tones.

20. The base station of claim 19, wherein said first period of time is at least 30 minutes.

21. The base station of claim 19, wherein the first and second control means are different, portion of a control routine;

and

where X is equal to one.

22. The base station of claim 19, wherein at least half of the N-X tones which are in said set of N tones but not in said set of X tones go unused during said second period of time.

23. The base station of claim 22, where none of the N-X tones in said set of N tones but not in said set of X tones are used during said second period of time.

24. The base station of claim 22, wherein multiple ones of the N-X tones is said set of N tones but not in said set of X tones are used during said second period of time.

25. The base station of claim 19, wherein said communications system is an orthogonal frequency division multiplexed system and wherein said second period of time is a period of time used to transmit an orthogonal frequency division multiplexed symbol.

26. The base station of claim 25, wherein said second period of time periodically repeats during said first period of time.

29. The method of claim 25, wherein at least one of said X tones is transmitted at predetermined fixed frequency.

27. A base station for use in an orthogonal frequency division multiplexed communications system the base station, the base station comprising:

a transmitter that uses a set of N tones to communicate information;

first control means coupled to said transmitter, for controlling the transmitter to transmitter over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10; and

second control means coupled to said transmitter for controlling the transmitter to transmit during a second period of time a second signal including a set of X tones, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time is allocated to said set of X tones, said second period of dine being a period of time used to transmit an orthogonal frequency division multiplexed symbol; and

third control means for controlling the transmitter to transmit during a third period of time a third signal including a set of Y tones, where Y≦

N, each tone in said third set of Y tones having 20% or less of said maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time, said third period of time having the same duration as said second period of time.

28. The method of claim 27, wherein said third period of time and said second period of time are disjoint, the method further comprising:

modulating at least two of data, control and pilot signals on at least some of said set of Y tones.

30. A base station for use in an orthogonal frequency division multiplexed communications system the base station, the base station comprising:

a transmitter that uses a set of N tones to communicate information;

first control means coupled to said transmitter, for controlling the transmitter to transmit over a first period of time using first signals, said first period of time being at least two seconds long, where N is larger than 10; and

second control means coupled to said transmitter for controlling the transmitter to transmit during a second period of time a second signal including a set of X tones, where X is less than 5, and where at least 80% of a maximum average total base station transmission power used by said base station transmitter during any 1 second period during said first period of time is allocated to said set of X tones, said second period of time being a period of time used to transmit an orthogonal frequency division multiplexed symbol; and

third control means for controlling the transmitter to transmit during a third period of time a fourth signal including G tones, where G is less than 5, and where at least 80% of said maximum average total base station transmitter power used by said base station transmitter during any 1 second period during said first period of time is allocated to said G tones.

31. The method of claim 30,

wherein the frequency of at least one of said G tones is a function of at least one of a base station identifier arid a sector identifier, and

wherein said at least one of said G tones is not one of said set of X tones.

32. The method of claim 30, wherein said second and third periods of time periodically repeat during said first period of time.

33. A method of operating a base station transmitter in an orthogonal frequency division multiplexed communications system, the method comprising:

operating the transmitter to transmit information using at least N tones in parallel during multiple symbol transmission time periods which occur during a first period of time, where N is larger than 10;

transmitting during second signal transmission time periods which occur on a periodic recurring basis during said first period of time, a signal including up to X tones, where X is less than 5, each of said second period of time being a symbol transmission time period long, and where at least 80% of the transmitter power used to transmit signals during each particular second period of time is allocated between said X tones which are transmitted during the particular second period of time, at least some of said N tones being intentionally left unused during each second period of time, the number of tones being intentionally left unused during each second period of time being greater than X, each of said X tones on which a signal is transmitted during a particular second period of time being allocated more signal transmission power during said particular second period of time than any tone which is not one of said X tones.

34. The method of claim 33, wherein at most 20% of the total transmission power used to transmit signals during each particular second signal time period is allocated to tones which are not included in the X tones used during the particular time period.

35. The method of claim 33, wherein the majority of said N tones go intentionally unused during each of said second transmission time periods.

36. The method of claim 34, wherein the number of said second time periods which occur in said first time period are a minority of the symbol transmission time periods which occur during said first time period.

37. The method of claim 33 were X is one.