MULTIPLE ACCESS WIRELESS COMMUNICATIONS SYSTEM USING A MULTI-SECTOR CONFIGURATION

• US 20080291856A1
• Filed: 05/13/2008
• Published: 11/27/2008
• Est. Priority Date: 08/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Lane, Frank
• Granted Patent: US 7,995,527 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• 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 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Power control methods and apparatus for use in a sectorized cell of an OFDM communications system are described. Each sector of a cell uses the same frequencies and transmission times and is synchronized with the other sectors in the cell in terms of tone frequencies used at any given time and symbol transmission times. Tones are allocated to channels in each cell in the same manner so that each channel in a sector has a corresponding channel in another sector. Power differences between channels in different sectors are maintained to be within a pre-selected power difference. Different channels in a cell are assigned different power levels. Wireless terminals are assigned to channels based on channel feedback information. Wireless terminals with poor channel conditions are allocated to higher power channels than wireless terminals with good channel conditions. Lower power channels often include more tones per symbol time than high power channels.

Claims

3-1. The method of claim 3, wherein the fixed fraction is less than 100%.

4. An apparatus for operating a transmitter within a cell of a wireless communication system, the cell including a first sector adjoining a second sector, comprising:

means for transmitting into the first sector and the second sector, in a synchronous manner, on first and second communications channels, wherein;

the first and second communications channels include a respective first subset and second subset of a set of tones during each of a respective first subset and second subset of a plurality of symbol times; and

the first subset of the set of tones and the second subset of the set of tones are different from each other during each of the plurality of symbol times; and

means for controlling a first total transmission power of the first subset of the set of tones transmitted into the first sector during the first subset of the plurality of symbol times to be a factor of a second total transmission power of the first subset of the set of tones transmitted into the second sector during the first subset of the plurality of symbol times.

5. The apparatus of claim 4, wherein the factor is greater than 0.2 (e.g. 20%) and less than 5 (e.g. 500%).

6. The apparatus of claim 4, wherein the first total transmission power and the second total transmission power are no more than a fixed fraction of a maximum average total transmission power used when transmitting within the first sector during any 1 hour period.

7. The apparatus of claim 6, wherein the fixed fraction is less than 100%.

8. An apparatus for operating a transmitter within a cell of a wireless communication system, the cell including a first sector adjoining a second sector, comprising:

a transmitter configured to transmit into the first sector and the second sector, in a synchronous manner, on first and second communications channels, wherein;

the first and second communications channels include a respective first subset and second subset of a set of tones during each of a respective first subset and second subset of a plurality of symbol times; and

the first subset of the set of tones and the second subset of the set of tones are different from each other during each of the plurality of symbol times; and

a controller configured to control a first total transmission power of the first subset of the set of tones transmitted into the first sector during the first subset of the plurality of symbol times to be a factor of a second total transmission power of the first subset of the set of tones transmitted into the second sector during the first subset of the plurality of symbol times.

9. The apparatus of claim 8, wherein the factor is greater than 0.2 (e.g. 20%) and less than 5 (e.g. 500%).

10. The apparatus of claim 8, wherein the first total transmission power and the second total transmission power are no more than a fixed fraction of a maximum average total transmission power used when transmitting within the first sector during any 1 hour period.

11. The apparatus of claim 10, wherein the fixed fraction is less than 100%.

12. A computer-program product for operating a transmitter within a cell of a wireless communication system, the cell including a first sector adjoining a second sector, comprising a computer readable medium having a set of instructions stored thereon, the set of instructions being executable by one or more processors and the set of instructions comprising:

instructions for transmitting into the first sector and the second sector, in a synchronous manner, on first and second communications channels, wherein;

the first and second communications channels include a respective first subset and second subset of a set of tones during each of a respective first subset and second subset of a plurality of symbol times; and

the first subset of the set of tones and the second subset of the set of tones are different from each other during each of the plurality of symbol times; and

instructions for controlling a first total transmission power of the first subset of the set of tones transmitted into the first sector during the first subset of the plurality of symbol times to be a factor of a second total transmission power of the first subset of the set of tones transmitted into the second sector during the first subset of the plurality of symbol times.

13. The method of claim 12, wherein the factor is greater than 0.2 (e.g. 20%) and less than 5 (e.g. 500%).

14. The method of claim 12, wherein the first total transmission power and the second total transmission power are no more than a fixed fraction of a maximum average total transmission power used when transmitting within the first sector during any 1 hour period.

15. The method of claim 14, wherein the fixed fraction is less than 100%.