Segmented digital pre-distortion method capable of realizing efficient hardware implementation

Abstract

The invention discloses a segmented digital pre-distortion method capable of realizing efficient hardware implementation, which comprises the following steps of performing time delay q = 0, 1,..., Q on input data x (n) to obtain xq (n), performing modulus square operation on the xq (n) to obtain | xq (n) | 2; comparing | xq (n) | 2 with a preset signal amplitude maximum value,wherein beta S is themaximum value of preset signal amplitude, taking a smaller value as input signal of S-1 SCPWQ primary function, and obtaining an output signal i = 1, 2,... S-1; multiplying the output signals by respective ciq, multiplying c0q by xq (n), and adding all multiplication results to obtain a calculation result with a time delay of q; summing all calculation results after the time delay q is equal to0, 1,..., Q to obtain an output result z (n) of the predistorter. After the scheme is adopted, the improved SCPWQ piecewise function is used for replacing a traditional power series and an SCPWL function to construct the predistorter, original input is replaced by a square term, and under the condition of complex signal input, square operation can be avoided through the improvement, so that hardware high-speed implementation is facilitated; an existing pre-distortion learning structure is not changed, the pre-distortion effect is improved, and the hardware implementation difficulty is reduced.

Description

technical field [0001] The invention relates to a segmented digital pre-distortion method that can be realized by efficient hardware. Background technique [0002] 1. About the digital predistorter [0003] In the fields of radio and television, communication, etc., the signal must be amplified by a power amplifier before transmission. Power amplifiers have natural nonlinear characteristics. If the power of the transmitted signal is large and enters the area where the nonlinearity of the power amplifier is serious, it will have a serious impact on the quality of the transmitted signal. In order to alleviate the influence of nonlinearity, the current practice is to add a pre-distortion module to the digital baseband part of the front end. The characteristics of this module are just opposite to those of the power amplifier, which can compensate the influence caused by the nonlinearity of the power amplifier, thereby improving the quality of the transmitted signal, such as fi...

AI Technical Summary

Problems solved by technology

[0005] 2. Existing technologies and their limitations

[0012] 2.2 Problems of Existing Power Series Memory Polynomial Predistorter

Figure 4 The main problem is that the data with small amplitude will be close to zero after high-order power operation, so that the hardware circuit can no longer distinguish these data. Therefore, the order of the existing power series polynomials generally does not exceed 5th order , so the effect of predistortion also has a limit that cannot be broken through

The root cause of this limit originates in the mathematics of the existing technology and thus cannot be solved by technically implemented methods

[0014] The power series polynomial predistorter is suitable for weakly nonlinear power amplifiers, and a high power is required for strong nonlinear power amplifiers, so the power series polynomial predistorter is not applicable

Moreover, new high-efficiency power amplifiers such as envelope tracking (ET) often have special AM-AM curve shapes, and power series polynomial predistorters cannot do anything about nonlinear compensation of these special shapes

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