l. (1979) Telecom 1, a national satellite for domestic Westwood, D.H. (1979) Customer premises RF terminals for the and business services, ICC-79, 1979 Int. Conf. on Communica- SBS system, ICC-79 INT. Conf. on Communications, 6.3/1.5. tions, Boston, MA (USA) 10-14 June, 49.5/1. Whittaker, P.N. (1980) Satellite Business Systems (SBS) - A Hogwood, P. (1977) PALAPA - Indonesia to the fore, J. Br Inter- concept for the 80s, Policy implications of Data Network Devel- planet, Soc. (GB) 30, (4) p. 127. opment in the OECD, p. 35. Point to multipoint urban and rural radio S AMohamed BSc MSc PhD CEng MIEE BT Laboratories Contents 52.1 Introduction 52/3 52.2 Urban multipoint systems 52/3 52.3 Rural multipoint systems 52/7 52.4 Economics of urban and rural systems 52/11 52.5 References 52/12 This page intentionally left blank Urban multipoint systems 52/3 52.1 Introduction Urban multipoint systems Radio systems have the following advantages over other trans- For urban applications such as data and integrated services digital mission media such as coaxial and optical cables: network (ISDN) access, multipoint systems are usually required to operate over relatively short hops of up to 7km to 10km. This requirement, coupled with the general non-availability of spectrum 1. Radio systems can be installed relatively quickly for permanent below about 10GHz (this spectrum is often used for high capacity or temporary applications. trunk radio systems) and the desirability to use small, compact, 2. Equipment can be recovered and re-used elsewhere. lightweight and unobtrusive roof top mounted equipment has led to 3. Ideal for use in hostile environment e.g. marshes, hilly terrain, the development of a number of multipoint systems in the 10.5GHz over water paths etc. to 26GHz bands (Mohamed, 1985; Nakayama, 1985; Omiveit, 4. Radio is more attractive to use when the demand for a new 1989; Shindo, 1983; and others). service is not certain or difficult to forecast. 5. Radio can provide media diversity to cable systems on routes The higher f