Interference Studies Between Mobile Satellite Service and Fixed Service in the Ku Band

Abstract

This paper examines the potential interference between the Mobile Satellite Service and the Fixed Service in the Ku band. At first, the mobile satellite stations operating at sea are presented and the aggregate and the single-entry interference criteria for the terrestrial fixed service stations are calculated. Then, all the parameters that influence the interference magnitude are presented and extensively analyzed. In order to evaluate the impact of each one of them in the interference calculations, different scenarios are taken into consideration and simulations are conducted in maritime and terrestrial environment. The results are thoroughly presented and analyzed. I. INTRODUCTION The increasing demand for Mobile Satellite Services the last decades has lead to the fast development of cost effective mobile VSAT terminals and their extensive use for many applications. Mobile VSAT antennae can easily be installed on almost every vehicle including cars, small vans, trucks, sea going vessels and mobile platforms like cruise ships, ferries, geo seismic ships, drilling vessels and oil production platforms. Many of these systems operate in the C band (6/4 GHz), while there is a great interest for their deployment in the Ku band (14/11/12 GHz) (uplink in 13.75-14.5 GHz and downlink in 10.7-12.75 GHz frequency bands) in geographic areas covered by these bands. These mobile satellite systems are used to provide wideband satellite services, such as streaming video, bringing Internet connectivity to remote areas and carrying sensitive voice or data traffic. The transmitting bit rates may vary between 19.2 kbps up to 1.544 Mbps (Ref 1). However, according to the International Telecommunication Union (ITU) Regulations, the 13.75-14.5 GHz and 10.7-12.75 GHz frequency bands are exclusive for the Fixed Satellite Service (FSS) in all ITU regions and allocated for use to the terrestrial Fixed Service (FS) in many countries around the world through ITU footnotes. Hence, whichever frequencies of operation for the mobile earth stations are chosen in the Ku band, there is a possibility of interference, either the earth station transmission interfering with reception at the Fixed Service stations (in the 13.75-14.5 GHz frequency band), or the Fixed Service station transmissions interfering with reception at the mobile earth stations (in the 10.7-12.75 GHz frequency band). The magnitude of interference between two systems operating in the same or adjacent frequency bands depends on many factors, such as the transmission loss along the interfering path and the permissible interference levels at the receivers. For the terrestrial Fixed Service, long- and short-term interference criteria have been established in order to facilitate the sharing with the other systems operating in the same frequency bands. The possibility and the magnitude of the interference need to be examined in detail in each case, taking all these factors that influence the interference into account. In case of a mobile earth station, significance must be given also to the time variant nature of the interference. That means that additional parameters should be taken into ) ( ) (