ACE Lab

논문 초록 (Abstract)

Background/Objectives: A new non-uniform lookup table (LUT) based Digital Pre-distortion (DPD) technique to reduce hardware complexity without degradation of DPD performance is proposed. Methods/Statistical analysis: The performance degradation of the power amplifier (PA) occurs due to the PAs nonlinearity. This paper considers the use of non-uniform LUT digital pre-distortion (DPD) to linearize the PA. In the proposed method, we reduce the LUT quantization error by allocating more tables in severe non-linear region while less tables in linear region. To recognize the nonlinear characteristics of the PA, we first estimate the PA characteristics and differentiate the characteristics. Findings: In recent mobile communication systems, linearization technology of PA is getting more and more important. Various linearization techniques have been studied to find the cost-effective technique, and DPD is known as one of the most effective methods to linearize PA. In particular, the LUT based DPD technique is used in a limited hardware resource environment due to its low computational complexity. However, it causes a quantization error when the size of the table is not enough big. To solve these problems, we propose a non-uniform LUT based DPD scheme. The conventional LUT DPD divides the magnitude of the input signals equally. The proposed LUT DPD, on the other hand, allocates a small number of tables in the linear region and a large number of tables in nonlinear region. By doing this, the linearization performance can be improved. We will show through simulation that the proposed method provides better linearization performance than the conventional LUT DPD if the same number of tables is used. Improvements/Applications: By applying this technique, we can achieve the same performance with less hardware resources, or the proposed method can improve linearization performance if the same LUT size is used. Key Words: Non-uniform LUT (Lookup Table), DPD (Digital pre-distortion), Nonlinear PA (Power amplifier), polynomial, Low hardware complexity