Diversity transmission using a single power amplifier
First Claim
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1. Apparatus for use in a radio transmitter, comprising:
- a first antenna;
a second antenna;
a power amplifier having an input for receiving a transmit signal and an output signal provided to the first antenna and to the second antenna for diversity transmission of the output signal to a radio receiver;
a phase shifter for shifting a phase of the output signal by a first amount before transmission over the second antenna so that a relative phase shift exists between the output signal transmitted from the first antenna and the output signal transmitted from the second antenna;
a power splitter for splitting the output signal into a first magnitude provided to the first antenna and a second magnitude provided to the phase shifter,electronic circuitry connected to control the phase shifter and configured to vary the first amount of phase shift applied by the phase shifter;
wherein the first and second magnitudes are variable and the electronic circuitry is configured to receive information from the radio receiver associated with the first amount of phase shift and information associated with an amount by which the electronic circuitry should vary the first and second magnitudes based on a magnitude difference between signals received from the first and second antennas.
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Accused Products
Abstract
Diversity radio transmission is accomplished with excellent performance using multiple antennas receiving a transmission signal from a single power amplifier. A data signal to be transmitted is provided to a first antenna, and a phase-shifted version of the data signal is applied a second antenna. The relative phase shift between the data signal transmitted over the two transmit antennas ensures the two antenna signals can be constructively combined at the receiver. In one non-limiting example embodiment, the relative phase shift is determined by processing pilot signals sent along with the data signal and which are transmitted with predetermined phase shifts.
10 Citations
19 Claims
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1. Apparatus for use in a radio transmitter, comprising:
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a first antenna; a second antenna; a power amplifier having an input for receiving a transmit signal and an output signal provided to the first antenna and to the second antenna for diversity transmission of the output signal to a radio receiver; a phase shifter for shifting a phase of the output signal by a first amount before transmission over the second antenna so that a relative phase shift exists between the output signal transmitted from the first antenna and the output signal transmitted from the second antenna; a power splitter for splitting the output signal into a first magnitude provided to the first antenna and a second magnitude provided to the phase shifter, electronic circuitry connected to control the phase shifter and configured to vary the first amount of phase shift applied by the phase shifter; wherein the first and second magnitudes are variable and the electronic circuitry is configured to receive information from the radio receiver associated with the first amount of phase shift and information associated with an amount by which the electronic circuitry should vary the first and second magnitudes based on a magnitude difference between signals received from the first and second antennas. - View Dependent Claims (2, 3, 4)
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5. Apparatus for use in a radio transmitter, comprising:
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a first antenna; a second antenna; a power amplifier having an input for receiving a transmit signal and an output signal provided to the first antenna and to the second antenna for diversity transmission of the output signal to a radio receiver; a phase shifter for shifting a phase of the output signal by a first amount before transmission over the second antenna so that a relative phase shift exists between the output signal transmitted from the first antenna and the output signal transmitted from the second antenna; and electronic circuitry connected to control the phase shifter and configured to vary the first amount of phase shift applied by the phase shifter, wherein the output signal is divided into multiple frames, each frame including a first pilot, a data portion, and a second pilot, and wherein a second amount of phase shift is associated with one of the first and second pilots and the first amount of phase shift is associated with the data portion. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A method for use in a radio transmitter that includes a first antenna, a second antenna, and a power amplifier, the method comprising:
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receiving at an input of the power amplifier a signal to be transmitted; providing an output signal from the power amplifier to the first antenna and to the second antenna; diversity transmitting the output signal from the first and second antennas to a radio receiver; shifting a phase of the output signal by a first phase shift amount before transmission over the second antenna so that a relative phase shift exists between the output signal transmitted from the first antenna and the output signal transmitted from the second antenna; determining the first phase shift amount so that the signals transmitted from the first and second antennas constructively combine at the radio receiver; splitting the output signal into a first magnitude provided to the first antenna and a second magnitude provided to the phase shifter, the first and second magnitudes are being variable; and receiving from the radio receiver information associated with the first amount of phase shift and information associated with an amount by which to vary the first and second magnitudes based on a magnitude difference between signals received from the first and second antennas. - View Dependent Claims (12, 13, 19)
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14. A method for use in a radio transmitter that includes a first antenna, a second antenna, and a power amplifier, the method comprising:
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receiving at an input of the power amplifier a signal to be transmitted; providing an output signal from the power amplifier to the first antenna and to the second antenna; diversity transmitting the output signal from the first and second antennas to a radio receiver; and shifting a phase of the output signal by a first phase shift amount before transmission over the second antenna so that a relative phase shift exists between the output signal transmitted from the first antenna and the output signal transmitted from the second antenna, wherein the output signal is divided into multiple frames, each frame including a first pilot, a data portion, and a second pilot, and wherein a second amount of phase shift is associated with one of the first and second pilots and the first amount of phase shift is associated with the data portion. - View Dependent Claims (15, 16, 17, 18)
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Specification