Beacon signaling in a wireless system

• US 20040109432A1
• Filed: 08/14/2003
• Published: 06/10/2004
• Est. Priority Date: 08/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Lane, Frank A.
• Granted Patent: US 7,366,200 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• 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 into a region, e.g., sector of a cell, 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 used for transmitting into said region 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 used for transmitting into the region is available for transmitting other tones with the power normally being distributed among multiple tones. Often 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 into a first region, 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 into said first region, 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 to transmit signals into the first region during any 1 second period during said first period of time is allocated to said set of X tones.

2. The method of claim 1, wherein said first region is a sector of a cell.

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

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 in the first region.

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 in the first region.

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 in the first region.

7. The method of claim 1,

wherein said first region is a sector of a cell;

and

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.

9. The method of claim 7, wherein said method further comprises:

transmitting during a third period of time a third signal into said first region 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 to transmit into said first region 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 of 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 and pilot signals on at least some of said set of Y tones.

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.

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. The method of claim 7, further comprising:

transmitting during a fourth period of time a fourth signal including G tones into the first region, 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 to transmit into said first region 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 fourth periods of time periodically repeat during said first period of time.

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

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 into a first region;

first control means coupled to said transmitter, for controlling the transmitter to transmit over a first period of time using first signals into the first region, 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 into said first region, 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 to transmit into the first region 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;

and

wherein said first region is a first sector of a cell including first and second sectors.

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 one or two.

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 in the first region during said second period of time.

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

24. The base station of claim 22, 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.

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.

27. The base station of claim 25, further comprising:

third control means for controlling the transmitter to transmit into the first region during a third period of time a third signal including a set of Y tones into the first region, 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 to transmit signals into the first region 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.

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

30. The method of claim 25, further comprising:

fourth control means for controlling the transmitter to transmit into the first region during a fourth 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 to transmit tones into the first region 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 and 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 31, wherein said second and fourth periods of time periodically repeat during said first period of time.