Radio communications using scheduled power amplifier backoff
First Claim
1. A method for controlling radio transmissions to multiple radio terminals, comprising:
- determining channel qualities of different radio channels associated with the radio terminals;
grouping first signals for a first number of radio terminals associated with a channel quality equal to or better than a predetermined level;
grouping second signals for a second number of radio terminals associated with a channel quality less than the predetermined level;
scheduling the first signals to be amplified by a power amplifier during a first time period;
scheduling the second signals to be amplified by the power amplifier during a second time period;
during the first time period, the power amplifier amplifying the first signals at a first power level and transmitting a first composite output signal; and
during the second time period, the power amplifier amplifying the second signals at a second power level higher than the first power level and transmitting a second composite output signal,wherein the first power level is a backed-off mean power level that reduces a probability of clipping as compared to a probability of clipping at the second power level which is also a mean power level.
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Accused Products
Abstract
Radio transmissions to multiple radio terminals are improved using scheduled backoff of a multi-signal power amplifier. A radio channel quality associated with each of the radio terminals is determined. First signals for first radio terminals associated with a better channel quality are amplified by a power amplifier during a first time period resulting in a first composite output signal. Second signals for second radio terminals associated with a lower channel quality are amplified by the power amplifier during a second time period resulting in a second composite output signal. Transmission during the first time period occurs at a first power level, e.g., mean power, that is associated with a lower probability of clipping the first composite output signal. During the second time period, the second composite signal is transmitted at a second power level, e.g., mean power, higher than the first power level which improves reception at the second terminals.
21 Citations
25 Claims
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1. A method for controlling radio transmissions to multiple radio terminals, comprising:
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determining channel qualities of different radio channels associated with the radio terminals; grouping first signals for a first number of radio terminals associated with a channel quality equal to or better than a predetermined level; grouping second signals for a second number of radio terminals associated with a channel quality less than the predetermined level; scheduling the first signals to be amplified by a power amplifier during a first time period; scheduling the second signals to be amplified by the power amplifier during a second time period; during the first time period, the power amplifier amplifying the first signals at a first power level and transmitting a first composite output signal; and during the second time period, the power amplifier amplifying the second signals at a second power level higher than the first power level and transmitting a second composite output signal, wherein the first power level is a backed-off mean power level that reduces a probability of clipping as compared to a probability of clipping at the second power level which is also a mean power level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for controlling radio transmissions to multiple radio terminals, comprising:
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a channel quality determination circuitry for determining channel qualities of radio channels associated with the radio terminals; scheduling circuitry for receiving the channel quality of a radio channel associated with each of the radio terminals, the scheduling circuitry being configured to schedule first signals for a first number of radio terminals associated with a channel quality equal to or better than a predetermined level for transmission during a first time period and to schedule second signals for a second number of radio terminals associated with a channel quality less than the predetermined level for transmission during a second time period; and a power amplifier for amplifying the first signals to output a first composite output signal and transmitting the first composite output signal at a first power level during the first time period, and for amplifying the second signals to output a second composite output signal and transmitting the second composite output signal at a second power level during the second time period, wherein the scheduling circuitry includes; buffering circuitry for buffering signals corresponding to the first and second numbers of radio terminals; a multiplexer coupled between the buffering circuitry and the power amplifier; a clipper for clipping an output of the multiplexer that exceeds a predetermined magnitude; and a scheduler for controlling which signals are provided from the buffering circuitry to the multiplexer or to the power amplifier. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. Base station apparatus for controlling radio transmissions to multiple radio terminals, comprising:
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a power amplifier; means for determining channel qualities of different radio channels associated with the radio terminals; means for grouping first signals for a first number of radio terminals associated with a channel quality equal to or better than a predetermined level; means for grouping second signals for a second number of a number of radio terminals associated with a channel quality less than the predetermined level; means for scheduling the first signals to be amplified by the power amplifier during a first time period; means for scheduling the second signals to be amplified by the power amplifier during a second time period; means for controlling the power amplifier during the first time period to amplify the first signals associated with the first number of radio terminals at a first power level and transmitting a first composite output signal; means for controlling the power amplifier during the second time period to amplify the second signals associated with the second number of radio terminals at a second power level higher than the first power level and transmitting a second composite output signal; means for transmitting the first composite signal to the first number of radio terminals at a first data rate higher than a second data rate at which the second composite signal is transmitted to the second number of radio terminals; and means for transmitting the first composite signal to the first number of radio terminals using a first modulation technique that has a higher order than a second modulation technique used to transmit the second composite signal to the second number of radio terminals. - View Dependent Claims (22, 23, 24, 25)
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Specification