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All Journal Journal of Engineering and Scientific Research (JESR) Jurnal Rekayasa elektrika
Helmy Fitriawan
University of Lampung
Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Engineering Industrial & Manufacturing Engineering

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Simulation and Modeling Time Response of Double Carrier Avalanche Photodiodes Helmy Fitriawan
Journal of Engineering and Scientific Research Vol. 2 No. 2 (2020)
Publisher : Faculty of Engineering, Universitas Lampung Jl. Soemantri Brojonegoro No.1 Bandar Lampung, Indonesia 35141

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1174.934 KB) | DOI: 10.23960/jesr.v2i2.45

Abstract

Avalanche photodiodes (APDs) is a particularly sensitive semiconductor device that employs the photoelectric effect to convert light into electricity. APDs can be used in some typical applications, i.e. imaging, optical fiber communications, range finding, laser scanners and laser microscopy. In APDs, avalanche multiplication occurred due to impact ionization when the devices operating at high electric fields. Unfortunately, avalanche multiplication decreases the time response of APDs. The time response of an APD can be characterized by its current response which is represented by the mean current as a function of time. This paper discusses a method to estimate the time response of double-carrier multiplication avalanche photodiodes (APDs). The model, called The Random Path Length (RPL), generates random path length for a carrier to impact ionize and takes account of dead space distance into the calculation. Dead space distance is the minimum distance to travel by a carrier to gain the adequate energy to start first ionization. The RPL is applied into an ideal structure which is assumed has a dimensionless multiplication length, w = 1.0, with electrons and holes moving in constant speeds, ve = vh = v, for various dead spaces distances, d*. In this research, a computer code is generated to compute the mean impulse response, i(t), and the standard deviation, s(t), of APDs all as a function of time.
Performance Evaluation of Dynamic Radio Resource Allocation for Ultra Dense Networks Reni Silvia Dewi; Misfa Susanto; Helmy Fitriawan
Jurnal Rekayasa Elektrika Vol. 22 No. 1 (2026): Vol. 22, No. 1, March 2026
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17529/jre.v22i1.506

Abstract

Ultra-Dense Networks (UDN) offer increased capacity and spectrum efficiency, but the densification of large number of femtocells also triggers complex co-tier and cross-tier interferences. This condition is major challenge in maintaining service quality on 5G and beyond network. This research presents an evaluation of dynamic radio resource allocation performance as an adaptive mechanism to reduce interference in dense UDN environments. Dynamic radio resource allocation selects channels based on minimum interference from neighbouring macrocells to adjust resource allocation to actual channel conditions. Simulations on three macrocells with 210 femtocells per cell show that dynamic radio resource allocation provides consistent performance improvements over conventional scheme. This method increases signal to interference plus noise (SINR) by 8-10 dB, shifts throughput toward higher values, reduces the probability of bit error rate (BER) > 0.01 from 45% to 28%, and reduces network energy consumption by approximately 25-30%. These results confirm that dynamic radio resource allocation is an effective, adaptive, and computationally light approach to improving signal quality and energy efficiency in high-density UDN.
Co-Authors Misfa Susanto Reni Silvia Dewi