Suriza A. Zabidi

The effect of weather on free space optics communication (FSO) under tropical weather conditions and a proposed setup for measurement

Free Space Optics communications (FSO) has attracted a lot of attention for a variety of applications in telecommunications field. The unlicensed, higher speed, broader and unlimited bandwidth, low cost solutions, and shortest deployment time frame are some of the drive to deploy FSO. However, weather attenuation has a big impact on the transmission line of FSO. There are a lot of studies and experiments have been done on FSO in the temperate climate region where the attenuation due to snow and fog are the two major problems in the deployment of FSO. However, there are no comprehensive study is done for the deployment of FSO in the tropical climate region where the rain and haze are present throughout the year. The objective of this paper is to produce analysis result of the different weather attenuations that have effect on FSO link. The parameters are attenuation due to geometric, molecular, atmospheric, rain, haze, and scintillation. The parameters are used to evaluate link availability of the FSO link. The result of the evaluation can provide more knowledge on the feasibility of FSO deployment under tropical weather condition especially for a long range link.

Environmental effects on free space earth-to-satellite optical link based on measurement data in Malaysia

FSO is a developing technology that has a great chance to compliment the traditional wireless communications and offer some inherent advantages compared to microwave links due to transmitting higher speed of data, easily deployment, and no license spectrum required. However, FSO is very vulnerable to the climatological phenomena such as fog, snow, rain, and haze that reduce the link availability. Most researches and studies are focusing on improving the FSO system for terrestrial link based on data in temperate region. Therefore, this paper is aiming to provide the feasibility analysis on performing FSO from earth to satellite in Malaysia as the performance of FSO is dependent on local weather conditions and in tropical region, the attenuations are dominant by rain and haze. The analysis is based on measurement of rain intensity, visibility and variation of optical free space signal level which has been done at Faculty of Engineering, International Islamic University (IIUM) Kuala Lumpur campus. From the terrestrial data, it will be scaled up for earth to satellite especially Low Earth Orbit (LEO) satellite and will be compared with calculated of FSO earth-to-satellite data. The analysis will determine the operability of FSO for long distance and as a benchmark for future design.

Investigating of rain attenuation impact on Free Space Optics propagation in tropical region

Free Space Optics (FSO) is an emerging technology in the area where higher speed and larger bandwidth is required. Technologically, FSO is similar to communication using fiber optic cables. Since the two technologies are similar, they share the same advantages such as higher speed, unlimited bandwidth and protocol independent. However, in term of cost and time for deployment, the cost to deploy FSO is cheaper and the deployment time is shorter since no cable is needed for FSO so the time and cost is reduce significantly. Although FSO has all the advantages of the best quality as communication medium, local weather condition is the drawback of FSO link performance. The aim of this paper is to investigate on this limitation with the focus on atmospheric attenuation on the propagation of FSO signal. General atmospheric attenuation will be discussed and the focus will be on rain. The motivation of this is to develop attenuation model that best represent tropical weather condition.

Analysis of Free Space Optics Link Availability with Real Data Measurement in Tropical Weather

Free Space Optical communications (FSO) has attracted a lot of attention for a variety of applications in telecommunications field. The unlicensed, higher speed, broader and unlimited bandwidth, low cost solutions, and shortest deployment period are some of the drives to deploy FSO. However, weather attenuation has a big impact on the transmission line of FSO. In temperate region a thorough studies are available on the link availability due to weather effect. In tropical region however most of FSO links install especially in Malaysia are as a backup system. There is no analysis on the FSO link availability under tropical weather condition. Therefore, the objective of this paper is to provide an analysis on the FSO link availability with real data measured in tropical weather condition. Based on one year measurement of rain attenuation and rain intensity, link availability of 99.99% can be achieved for a link distance of 1.25km and fade margin of 25dB. The outcome of this research is expected to give a foundation for the design and development of a long range FSO link under tropical weather condition.

Availability Assessment of Free-Space-Optics Links With Rain Data From Tropical Climates

Rainfall in tropical environments acts as a dominant parameter for estimating the availability of free-space optics (FSO). Long fades are caused by precipitation in particular heavy rains, and this precipitation increases atmospheric attenuation due to rain and reduces the availability of optical power from FSO links. In this paper, the link availability of an FSO system is estimated under the impact of rain in a tropical climate. The influence of rain on the propagation of FSO signal is investigated based on experimental and statistical analyses of rain-rate measurements under tropical conditions. Rain-rate data are measured in Malaysia for three years and used to estimate the availability of FSO links. Models developed in Malaysia are used to predict atmospheric attenuation due to rain. Long-term statistical measurements of rain data can enable good estimation of link availability. Based on the prediction model and measured rain-rate data, the FSO link budget is analyzed, and the link availability as a function of distance is predicted. Carrier class availability limits the FSO link to a few hundred meters only, whereas enterprise class availability can exceed FSO links over a few kilometers long.