Method and system for baseband predistortion linearization in multi-channel wideband communication systems
First Claim
Patent Images
1. A method comprising:
- generating an address from samples of a baseband input signal, u(n-k), of a communication system, wherein k is a counter corresponding to a plurality of taps;
retrieving from a memoryless lookup table an entry, Fm(|u(n)−
k|), in accordance with the address for each tap of the plurality of taps;
multiplying the baseband input signal and the entry from the memoryless lookup table to generate a multiplied signal, x(n−
k)=u(n−
k)·
Fm(|u(n−
k)|) for each tap of the plurality of taps;
pre-equalizing the multiplied signal by multiplying, for each tap of the plurality of taps, the multiplied signal, x(n−
k), with an indexed coefficient corresponding to a magnitude of the baseband input signal, Wkm(|u(n)|), to generate a pre-equalized signal for each tap of the plurality of taps;
summing the pre-equalized signal for each tap of the plurality of taps to generate an output signal, z(n)=Σ
k=0KWkm(|u(n)|)·
x(n−
k); and
outputting the output signal, z(n), to a power amplifier.
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Abstract
An efficient baseband predistortion linearization method using effective multiplexing modulation technique such as wideband code division multiple access and orthogonal frequency division multiplexing is disclosed. The present invention is based on the method of piecewise pre-equalized lookup table based predistortion, which is a cascade of a lookup table predistortion and piecewise pre-equalizers.
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Citations
18 Claims
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1. A method comprising:
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generating an address from samples of a baseband input signal, u(n-k), of a communication system, wherein k is a counter corresponding to a plurality of taps; retrieving from a memoryless lookup table an entry, Fm(|u(n)−
k|), in accordance with the address for each tap of the plurality of taps;multiplying the baseband input signal and the entry from the memoryless lookup table to generate a multiplied signal, x(n−
k)=u(n−
k)·
Fm(|u(n−
k)|) for each tap of the plurality of taps;pre-equalizing the multiplied signal by multiplying, for each tap of the plurality of taps, the multiplied signal, x(n−
k), with an indexed coefficient corresponding to a magnitude of the baseband input signal, Wkm(|u(n)|), to generate a pre-equalized signal for each tap of the plurality of taps;summing the pre-equalized signal for each tap of the plurality of taps to generate an output signal, z(n)=Σ
k=0KWkm(|u(n)|)·
x(n−
k); andoutputting the output signal, z(n), to a power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system comprising:
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an address generator configured to generate an address from samples of a baseband input signal, u(n−
k), of a communication system, wherein k is a counter corresponding to a plurality of taps;a memoryless lookup table configured to assign a coefficient, Fm(|u(n)−
k|), according to the address for each tap of the plurality of taps;a multiplier configured to combine the baseband input signal and the coefficient to generate a multiplied signal, x(n−
k)=u(n−
k)·
Fm(|u(n−
k)|) for each tap of the plurality of taps;an equalizer configured to pre-equalize the multiplied signal by multiplying, for each tap of the plurality of taps, the multiplied signal, x(n−
k), with an indexed coefficient corresponding to a magnitude of the baseband input signal, Wkm(|u(n)|), to generate a pre-equalized signal for each tap of the plurality of taps;a summer configured to sum the pre-equalized signal for each tap of the plurality of taps to generate an output signal, z(n)=Σ
k=0KWkm(|u(n)|)·
x(n−
k); anda power amplifier configured to receive the output signal, z(n). - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification