Rain attenuation effects in considering the feasibility of stratospheric communication platforms for rural areas of South Africa.

Abstract

Also known as High Altitude Platform Stations (HAPS), these systems employ unmanned or

manned, solar or fuel energy airships or aircraft carrying payloads with transponders and antennas.

These remote airships or aircraft offer a much more cost effective solution for coverage of

certain regions including: urban, suburban, rural and other environments with low population

densities. The Stratospheric Communications Platform (SCP) network offers a better solution

than existing Cellular Radio Systems for telecommunication and multimedia services, with

greater speed of transmission than even optical modes. It would be virtually impossible to construct

land lines and microwave networks in remote, one thousand square-kilometre rural areas.

There are other drawbacks to wired deployment as well. The cost of copper wire is astronomical,

the terrain harsh and inaccessible and the population scattered. The aim of this dissertation

is to illustrate that the use of a platform of this nature is suitable to the rural environment of

South Africa. This work includes a case study to ascertain the feasibility of a high altitude platform

approach to telecommunication service provision for rural areas. Realising its feasibility

has led to an intensive study of rain attenuation. The specific attenuation calculated for a South

African rural area (Ulundi) is compared to lTV values. A performance evaluation of the SCP

has been done via a link budget calculation with the calculated attenuation values used as input

parameters. The advantages of SCPs due to lower path loss, mobile power consumption and

system cost are documented. A cellular network architecture is proposed and future investigations

into station-keeping techniques, payload power and platform placement are discussed.