Transmission device with adaptive digital predistortion, transceiver with transmission device, and method for operating a transmission device
First Claim
1. A transmission device with adaptive digital predistortion, comprising:
- a processor unit for providing a first discrete-value component (I) of a baseband signal (DAT1) at a first output and a second discrete-value component (Q) at a second output;
a predistortion unit, connected to the outputs of the processor unit, having a first and a second input and having a first and a second output, wherein the predistortion unit comprises a coefficient unit for ascertaining a predistortion coefficient (KOEFF1), representing a complex value, on the basis of a first control signal (CONT1) at a first control input on the coefficient unit, a level for the first component (I), which is applied to the first input, and a level for the second component (Q), which is applied to the second input, wherein the predistortion unit comprises a multiplication unit for outputting an output signal (DAT2), derived from the first component (I), and from the second component (Q), and from the predistortion coefficient (KOEFF1), having a first discrete value component (I2) at the first output and having a second discrete value component (Q2) at the second output, wherein the predistortion unit comprises an adaptation unit for generating, and for transmitting to the coefficient unit, a new complex predistortion coefficient (KOEFF2) from at least one of the first component (I), the second component (Q), the first control signal (CONT1) and a second baseband signal (DAT3) which is applied to a second control input and comprises a first component (I3) and a second component (Q3);
a modulation device having a first input, which is operatively coupled to the first output of the predistortion unit, having a second input, which is operatively coupled to the second output of the predistortion unit, having a local oscillator input and having an output for providing signals applied to the input side and converted into an output signal using a local oscillator signal;
at least one amplification device having an input which is operatively coupled to the output of the modulation device;
an output unit, connected to the output of the at least one amplification device, for outputting a portion of an output signal from the at least one amplifier arrangement;
a conversion unit for converting the portion of the output signal into a baseband signal (DAT3) comprising a first and a second discrete value component (I3, Q3), having an input, which is connected to the output unit, and a first output for providing the first discrete value component (I3) and a second output for providing the second discrete value component (Q3), which are respectively coupled to one of at least two connections on the second control input of the predistortion unit;
wherein the predistortion unit has a first and a second operating state, and in the first operating state is configured to output signals (I) applied to the first input at the first output and signals (Q) applied to the second input at the second output, and in the second operating state is configured to output the first and second components (I2, Q2) of the derived output signal (DAT2) at the first and second outputs, wherein the predistortion unit can be switched to the first or to the second operating state by the first control signal (CONT1) at the control input, and a power control unit having an input for supplying a discrete-value power control signal (LS) to provide the first control signal (CONT1) at a first output, which is operatively coupled to the control input of the predistortion unit.
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Abstract
The invention provides a transmission device having adaptive digital predistortion, which has a transmission path and a feedback path. The transmission path contains a predistortion unit which takes a derived control signal (LS) and baseband signals applied to the input side as a basis for calculating the address of a predistortion coefficient (KOEFF1) stored in a memory and logically combines this predistortion coefficient with the applied baseband signals in a complex multiplication unit. The use of complex coefficients and of the complex multipliers allows compensation both for AM/AM distortion and for AM/PM distortion in an amplifier device connected downstream of the predistortion unit. Usefully, the feedback path of the transmission device with digital adaptive predistortion can also be implemented using the reception device in a transceiver.
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Citations
13 Claims
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1. A transmission device with adaptive digital predistortion, comprising:
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a processor unit for providing a first discrete-value component (I) of a baseband signal (DAT1) at a first output and a second discrete-value component (Q) at a second output;
a predistortion unit, connected to the outputs of the processor unit, having a first and a second input and having a first and a second output, wherein the predistortion unit comprises a coefficient unit for ascertaining a predistortion coefficient (KOEFF1), representing a complex value, on the basis of a first control signal (CONT1) at a first control input on the coefficient unit, a level for the first component (I), which is applied to the first input, and a level for the second component (Q), which is applied to the second input, wherein the predistortion unit comprises a multiplication unit for outputting an output signal (DAT2), derived from the first component (I), and from the second component (Q), and from the predistortion coefficient (KOEFF1), having a first discrete value component (I2) at the first output and having a second discrete value component (Q2) at the second output, wherein the predistortion unit comprises an adaptation unit for generating, and for transmitting to the coefficient unit, a new complex predistortion coefficient (KOEFF2) from at least one of the first component (I), the second component (Q), the first control signal (CONT1) and a second baseband signal (DAT3) which is applied to a second control input and comprises a first component (I3) and a second component (Q3);
a modulation device having a first input, which is operatively coupled to the first output of the predistortion unit, having a second input, which is operatively coupled to the second output of the predistortion unit, having a local oscillator input and having an output for providing signals applied to the input side and converted into an output signal using a local oscillator signal;
at least one amplification device having an input which is operatively coupled to the output of the modulation device;
an output unit, connected to the output of the at least one amplification device, for outputting a portion of an output signal from the at least one amplifier arrangement;
a conversion unit for converting the portion of the output signal into a baseband signal (DAT3) comprising a first and a second discrete value component (I3, Q3), having an input, which is connected to the output unit, and a first output for providing the first discrete value component (I3) and a second output for providing the second discrete value component (Q3), which are respectively coupled to one of at least two connections on the second control input of the predistortion unit;
wherein the predistortion unit has a first and a second operating state, and in the first operating state is configured to output signals (I) applied to the first input at the first output and signals (Q) applied to the second input at the second output, and in the second operating state is configured to output the first and second components (I2, Q2) of the derived output signal (DAT2) at the first and second outputs,wherein the predistortion unit can be switched to the first or to the second operating state by the first control signal (CONT1) at the control input, and a power control unit having an input for supplying a discrete-value power control signal (LS) to provide the first control signal (CONT1) at a first output, which is operatively coupled to the control input of the predistortion unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for regulating predistortion of a discrete value signal (DAT1) in a transmission device, comprising:
multiplying first and second components (I, Q) of the signal (DAT1) by a complex predistortion coefficient (KOEFF1) when a level for an output signal from a regulatable amplification device is exceeded as determined by a control signal (CONT1), where the coefficient (KOEFF1) is dependent on respective levels of the first and second components (I, Q) of the signal (DAT1) and on a control signal (CONT1).
Specification