Feasibility study of free-space optical communication for South Africa

Abstract

This paper aims to determine the feasibility of deploying free-space optical communication (FSOC) technology in South Africa. In order to achieve this aim, visibility, wind speed, and altitude data for several potential deployment locations over a period of 4 years have been used to compute the FSOC-based atmospheric losses under average and worst case atmospheric conditions. Results have shown that Ermelo has the highest optimal FSOC link distance of 7.5 km at an overall atmospheric loss of 2.8 dB under average conditions, while Durban has the shortest FSOC link distance at 2.6 km at an overall atmospheric loss of 12 dB under worst case conditions. It has also been found that the refractive index structure parameter is mainly altitude dependent. The parameter is larger at lower altitudes due to the more significant heat transfer between the air and the surface. Overall, this study has shown that FSOC technology deployment in South Africa is largely feasible (i.e., deployable with good reliability) for last mile broadband access networks, where link distances between transceivers measure 10 km on average. These results have been based on theoretical models, which take into account reasonable realistic assumptions of worst case atmospheric and the transceiver system parameter losses.