Synchronization techniques for a wireless system
First Claim
1. A communication method for use in a base station of a cell, the base station transmitting symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the method comprising:
- operating each sector to use a set of tones to transmit orthogonal frequency division multiplexed symbols, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and controlling each sector to simultaneously use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times.
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Accused Products
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.
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Citations
24 Claims
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1. A communication method for use in a base station of a cell, the base station transmitting symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the method comprising:
operating each sector to use a set of tones to transmit orthogonal frequency division multiplexed symbols, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and controlling each sector to simultaneously use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times. - View Dependent Claims (2)
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3. A communication method for use in a base station of a cell, the base station transmitting symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the method comprising:
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operating each sector to use a set of tones to transmit orthogonal frequency division multiplexed symbols, each orthogonal frequency division multiplexed symbol having a symbol transmission start time; controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; using a set of hopping sequences to allocate tones to a first set of communication channels in a first sector of said cell; and using said set of hopping sequences to allocate tones to a corresponding set of communication channels in each of the other sectors of said cell, each hopping sequence having a start time, the start time of each hopping sequence in said set of hopping sequences being the same in each of said sectors. - View Dependent Claims (4, 5, 6, 12)
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7. A communication method for use in a base station of a cell, the base station transmitting symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the method comprising:
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operating each sector to use a set of tones to transmit orthogonal frequency division multiplexed symbols, each orthogonal frequency division multiplexed symbol having a symbol transmission start time; controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; and transmitting a portion of pilot tones in each sector of the cell according to a pilot tone hopping sequence, the same pilot tone hopping sequence being used in each sector but with a different fixed tone offset being used in each of the sectors of a cell. - View Dependent Claims (8, 9)
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10. A communication method for use in a base station of a cell, the base station transmitting symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the method comprising:
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operating each sector to use a set of tones to transmit orthogonal frequency division multiplexed symbols, each orthogonal frequency division multiplexed symbol having a symbol transmission start time; controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; transmitting pilot tones in each sector of the cell according to a set of pilot tone hopping sequences, the same set of pilot cone hopping sequences being used in each sector but with different fixed tone offsets being used in each of the sectors of the cell; and wherein pilot tone hopping sequences in a set of pilot tone hopping sequences corresponding to a sector are offset from each other by a corresponding preselected set of offsets, the corresponding preselected set of offsets being the same in each sector of the cell. - View Dependent Claims (11)
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13. A control system for use in a base station of a cell, the base station transmitting modulation symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the system comprising:
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a transmitter assembly for transmitting signals into multiple sectors of said cell; and means for controlling the transmitter to transmit orthogonal frequency division multiplexed symbols into each sector of the cell, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and for controlling each sector to simultaneously use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times. - View Dependent Claims (14)
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15. A control system for use in a base station of a cell, the base station transmitting modulation symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the system comprising:
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a transmitter assembly for transmitting signals into multiple sectors of said cell; means for controlling the transmitter to transmit orthogonal frequency division multiplexed symbols into each sector of the cell, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and for controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; means for generating a set of hopping sequences used to allocate tones to a first set of communication channels in a first sector of said cell; and means for allocating tones to a corresponding set of communication channels in each of the other sectors of said cell according to said set of hopping sequences, each hopping sequence having a start time, the start time of each hopping sequence in said set of hopping sequences being the same in each of said sectors. - View Dependent Claims (16, 17, 18, 24)
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19. A control system for use in a base station of a cell, the base station transmitting modulation symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the system comprising:
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a transmitter assembly for transmitting signals into multiple sectors of said cell; means for controlling the transmitter to transmit orthogonal frequency division multiplexed symbols into each sector of the cell, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and for controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; and means for generating pilot tones in each sector of the cell according to a pilot tone hopping sequence, the same pilot tone hopping sequence being used in each sector but with a different fixed tone offset being used in each of the sectors of a cell. - View Dependent Claims (20, 21)
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22. A control system for use in a base station of a cell, the base station transmitting modulation symbols into multiple sectors of said cell using orthogonal frequency division multiplexed symbols, the system comprising:
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a transmitter assembly for transmitting signals into multiple sectors of said cell; means for controlling the transmitter to transmit orthogonal frequency division multiplexed symbols into each sector of the cell, each orthogonal frequency division multiplexed symbol having a symbol transmission start time, and for controlling each sector to use the same set of tones, the same duration of each symbol transmission period, and substantially the same symbol start times; and means for transmitting pilot tones in each sector of the cell according to a set of pilot tone hopping sequences, the same set of pilot tone hopping sequences being used in each sector but with different fixed tone offsets being used in each of the sectors of the cell, pilot tone hopping sequences in a set of pilot tone hopping sequences corresponding to a sector being offset from each other by a corresponding preselected set of offsets, the corresponding preselected set of offsets being the same in each sector of the cell. - View Dependent Claims (23)
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Specification