基于高次项的三频段数字预失真算法研究

Tri-band Digital Pre-distortion based on High-Order Intermodulation

载波聚合是LTE-A中的关键技术,分为连续和非连续两类。和频段内连续/非连载波聚合相比,频带间非连续载波聚合对射频前端的成本和功耗要求更高。功放作为射频前端的重要组成部分,它的成本和功耗在射频前端占比很高,而三频段高效功放加数字预失真是解决上述难题的有效措施。因此,介绍三频功放非线性失真特征,重点研究三频段功放非线性模型,针对传统模型对高阶非线性拟合效果差的问题,导出三频段高次项模型,并进行仿真验证。

CA(Carrier Aggregation),as a key feature of LTE-A,may be divided into two categories of continuous CA and discontinuous CA;as compared with intra-band contiguous CA and intra-band noncontiguous CA,inter-band CA challenges the cost and power consumption of AFE(Analog Front-End).As an important part of AFE,PA(Power Amplifier)has a high cost and power consumption in the AFE,while tri-band high-efficiency PA plus digital pre-distortion would be a feasible way to cope with the above challenge.This paper firstly introduces the nonlinear distortion of tri-band PA,with focus on modeling the nonlinear distortion of tri-band PA.Aiming at the problem that the traditional model has poor fitting performance of high-order nonlinear,a novel high-order intermodulation model is derived and verified by with simulation.