SFOL DME Performance Improvement of Memory Polynomial DPD with Regularization

Seowoo Park, Sunghwa Lee, Jiwon Seo, Euiho Kim*

The Distance Measurement Equipment (DME) is an alternative navigation system used when a satellite navigation system is unavailable. Although SFOL pulses are 4.5 times stronger than Gaussian pulses used in conventional DME, distortion occurs in SFOL pulses output due to nonlinear characteristics of DME amplifiers. Digital pre-distortion (DPD) resolves distortion by implementing pre-distorter before amplifier circuit. DME RF amplifiers were modeled based on a memory polynomial model and solved the distortion of SFOL pulses through Matlab-based DPD. However, memory polynomial models composed of SFOL pulses have high condition number and are vulnerable to input errors. In this work, the performance of SFOL DME was improved by securing the stability of memory polynomial DPD, and reduced modeling errors by applying regularization techniques.

Keywords: DME, SFOL, PA, PD, DPD, regularization