Katzis, Konstantinos

Like with the past generations of mobile cellular networks, deployment of 5G services in rural areas are expected to be financially and technically challenging. Currently, researchers around the globe explore the possibility of employing the underutilized/unused portion of TV spectrum referred to as TV White Spaces (TVWS) as a low-cost alternative to traditional licensed type of wired/wireless broadband networks and possibly as a way to bridge the gap of broadband service availability between rural and urban areas. Delivering TVWS services from High Altitude Platforms (HAPs) is an option that many developed/developing countries can use to provide broadband services over many of their rural and low-income population. This work presents the advantages of employing TVWS spectrum from HAPs as well as the challenges of this type of communication architecture. More specifically, this work proposes a novel communication type of architecture where HAPs are delivering broadband services using the TVWS spectrum. Taking advantage of their position in the sky and the centralized nature of the communication system, they deliver communications over a wide area while monitoring and optimizing radio resource allocation. The paper evaluates the performance of such a system based on the IEEE 802.22 standard and the free space path-loss model ITV-R P.452.

Due to the favorable propagation characteristics of the spectrum allocated for broadcast Television in the Very High Frequency (VHF) and Ultra High Frequency (UHF) spectrum bands; new innovative wireless technologies have emerged capable to operate on a secondary basis in the unused spectrum portions assigned to incumbent Television broadcasters. Television White Spaces (TVWS) is an umbrella term used to describe the unused portions of spectrum in the broadcast Television bands. Regulatory authorities require that White Space Devices (WSDs) must protect receivers of the incumbent services at the edge of the incumbent broadcast Television coverage contours from possible harmful interference. In this paper, we present a detailed mathematical framework for calculating the sufficient keep-out-distance (dk) between Digital TV (DTV) services and WSDs to allow the use of TVWS spectrum without causing interference to the receivers of the incumbent services in the Ethiopian context. The framework includes the calculation of co-channel and adjacent distance dk from the DTV contour using the ITU-R P. 1546-5 and ITU-R P.1411-9 propagation models respectively. The paper elaborates on how to compute the desired distance (ddesired) of DTV services using the interpolation approach. In addition, we simulate the adjacent and co-channel distance dk with respect to antenna Height Above Average Terrain (HAAT) values.