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All Journal International Journal of Electrical and Computer Engineering TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics Indonesian Journal of Electrical Engineering and Computer Science
Jafri Din
Universiti Teknologi Malaysia
Computer Science & IT Electrical & Electronics Engineering

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Comparison of Raindrop Size Distribution Characteristics Across the Southeast Asia Region Manhal Alhilali; Lam Hong Yin; Jafri Din
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 6: December 2018
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v16i6.10091

Abstract

Satellite communication requires reliable estimates of the channel characteristics, especially with the future use of higher frequencies. Regardless of the rain rate, the shape of rain drop size distribution (DSD) start to considerably effect the specific attenuation. In this study DSDs are studied using ground-based two-dimensional video disdrometer measurements taken from Johor, Malaysia as well as two similar datasets from Gan and Manus, two equatorial islands. Integral rain parameters are studied to explain DSD variations across the Southeast Asia region. Slightly higher raindrop concentrations and larger diameters were observed in Johor than in Gan or Manus, which is due to Johor being affected by not only oceanic rain- fall but land rainfall as well. The measured rainfall was classified into convective and stratiform precipitation types; the results showed that the Southeast Asia region is dominated by convective rain in terms of accumulated rainfall amount, but stratiform rain occurred more frequently. Further, seasonal variations observed in Johor were insignificant and the DSD variation was mostly due to changes in percentage occurrence of the precipitation types for each monsoon season.
Effects of reduction factor on rain attenuation predictions over millimeter-wave links for 5G applications M. Rashid; Jafri Din
Bulletin of Electrical Engineering and Informatics Vol 9, No 5: October 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (512.682 KB) | DOI: 10.11591/eei.v9i5.2188

Abstract

Millimeter-wave will be the strong contender for the terrestrial link using for 5G networks. So it is imperative to examine these frequency bands to ensure the uninterrupted services when 5G network is connected in tropical regions. A critical challenge of link-budgeting in mm-wave 5G networks is the precise estimation of rain attenuation for short-path links. The difficulties are further intensified in the tropical areas where the rainfall rate is very high. Different models are proposed to predict rain attenuation, however recent measurements show huge discrepancies with predictions for shorter links at mm-wave. The path reduction factor is the main parameter in the prediction model for predicting total attenuation from specific rain attenuation. This study investigates four path reduction factor models for the prediction of rain attenuation. A comparison was made between these models based on rain attenuation data measured at 26 GHz at 300 m and 1.3 km links in Malaysia. All models are found to predict rain attenuation at a 1.3 km link with minimum errors, while tremendous discrepancies are observed for 300 m link. Hence it is highly recommended to further investigate the reduction factor model for shorter links less than 1 km
Characterization of concurrent ku band tropospheric scintillation and rain attenuation in Malaysia Ibtihal Fawzi Elshami; Jafri Din; Lam Hong Yin; Ali I Elgayar
Indonesian Journal of Electrical Engineering and Computer Science Vol 15, No 2: August 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v15.i2.pp956-961

Abstract

Tropospheric scintillation in satellite communication systems operating at frequencies over 10 GHz is a significant impairment, especially in tropical regions, as attenuation affects scintillation dramatically. This work concentrates on tropospheric scintillation in equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement study utilising a direct broadcast receiver and an automatic weather station. This study aimed to investigate the relationship between wet scintillation and rain attenuation using experimental measurements. The power spectral analysis has been carried out to determine required cut-off frequency of filtering to separate out rain attenuation and scintillation effects. The results can provide significant information on the fluctuations of wet scintillation at Ku-band earth space link in tropical regions.
Interference and Electromagnetic Compatibility Challenges in 5G Wireless Network Deployments Idrissa Abubakar; Jafri Din; Manhal Alhilali; Hong Yin Lam
Indonesian Journal of Electrical Engineering and Computer Science Vol 5, No 3: March 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v5.i3.pp612-621

Abstract

5G wireless network technology is going operate within the environment of other electrical, electronic and electromagnetic devices, components and systems, with capability of high speed data connectivity acting as network transceiver stations with Massive MIMO for Internet of Things (IoT). Considering the level of interoperability, electromagnetic Interference and electromagnetic compatibility to avoid electromagnetic pulse effects (EMP) which is capable of not only causing network malfunctions but total devices and equipments failure in mission critical operations, like hospital MRI scan machines, security profiling and data handling or even personal healthcare devices like heart pacemaker. Electromagnetic energy coupling in PCB due to: radiation, reflection and Crosstalk generates reliability challenges affecting Signal Integrity between traces of multilayer boards stalks, power bus and packaging creating Electromagnetic interference (EMI) in PCB leading false clock response to system failure. Above were considered very essential when deploying 5G wireless network facility as presented in this paper. 
Estimation of Millimeter Wave Attenuation Due to Rain using 2D Video Distrometer Data in Malaysia Manhal Alhilali; Jafri Din; Michael Schönhuber; Hong Yin Lam
Indonesian Journal of Electrical Engineering and Computer Science Vol 7, No 1: July 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v7.i1.pp164-169

Abstract

The increasing use of millimeter wave frequency bands requires a good understanding of the atmospheric channel. In equatorial regions, rain plays the central role in the impairment of millimeter wave propagation. Using large amounts of precise data collected by a two-dimensional video distrometer in Malaysia, the rain-specific attenuation of both vertically and horizontally polarized waves at the 38 GHz frequency was computed by applying the T-matrix technique. Good agreement is observed between these computations and fitted power law models from neighboring areas, but the ITU-R Recommendation P.838-3 significantly underestimates the rain-specific attenuation. The importance of including raindrop axial ratio in the calculation is revealed by differences among the local fitted coefficients for the vertically polarized estimations. The power law fit is provided, and the measurement is verified.
Rain attenuation statistics over 5G millimetre wave links in Malaysia Mustafa Ghanim; Manhal Alhilali; Jafri Din; Hong Yin Lam
Indonesian Journal of Electrical Engineering and Computer Science Vol 14, No 2: May 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v14.i2.pp1012-1017

Abstract

Millimetre wave band is a solid contender to be utilized for the future 5G wireless systems deployment. Rain-induced attenuation is a major disadvantage at these frequencies. This paper presents statistics of rain-induced attenuation and rainfall data for two years of horizontally polarized links propagating at 38 GHz and 26 GHz over a terrestrial path link of 301 meters. From the analysed datasets, a rain rate around 116 mm/h exceeded at 0.01% of the time of an average year, while the links recorded 16 and 9.5 dB at the same percentage of time for 38 and 26 GHz respectively. The study aims to identify the prediction model that deliver most reasonable predictions for 5G links operating in Malaysian tropical climate. ITU-R P.530-17, Mello’s, and Ghiani’s models were all examined. Using ITU-R model, relative error margins of around 3.8%, 30% and 49.7% alongside 22.3, 9.5, 33% were obtained in 0.1%, 0.01% and 0.001% of the time for 26 and 38 GHz respectively.  Curiously, ITU-R model demonstrates better predictions to measured rain attenuation with lower error probability. This study highlights the need for new prediction models for short path-length 5G links and helps to improve the design of terrestrial links operating at millimetre wave frequencies in tropical regions.
Co-Authors Ahmad Syahril Mohd Nawi Ali I Elgayar Ali l Elgayar Anton Yudhana Athanasios D. Panagopoulos Felix Obite Hong Yin Lam Hong Yin Lam Ibtihal F El-shami Ibtihal Fawzi Elshami Ibtihal Fawzi Elshami Idrissa Abubakar Kamaludin Mohammad Yusof Lam Hong Yin Lam Hong Yin M. Rashid Manhal Alhilali Masoud Mohebbi Nia Michael Schönhuber Mohammad Ibrahim Abozeed Mustafa Ghanim Omar Abdul Aziz Raja Bidin Raja Hassan Saberi Mawi Sunardi, Sunardi Syed Abdullah