Mobile communications and the Federal Telecommunications System

Abstract

The first major radio program of the Federal Telecommunications System has been the installation of an extended-coverage VHF Mobile Telephone System for evaluation of the common-user concept of reducing the number of frequencies required by several users by time sharing. Subscribers are provided three-channel full-duplex dial-up service, with such features as direct dialing of any other mobile, as well as any telephone, in the Federal Telecommunications System, automatic busy-channel lockout, manual operator access to all three channels, automatic calling channel reverting, and repetitive ringing to the mobiles. Coverage is provided over 40 per cent of the State of Massachusetts and parts of the States of Connecticut, New Hampshire and Rhode Island. For the pilot study, 40 vehicles belonging to 15 separate users will share the system. After system evaluation, the number of channels will be increased to allow system expansion for coverage of 90 percent of the New England area, with a cor responding increase in the number of vehicles and users.Federal Telecommunications System programs of the future include the installation of systems in other areas to study common-user inter-city emergency systems and extended coverage multi purpose telephone/dispatch systems on a commonuser basis.

Otimização multidimensional baseada em heurísticas aplicada aos sistemas de comunicação sem fio.

“…O IMTS consistia de um transmissor de alta potência na frequência de 150 MHz que cobria uma área com aproximadamente 90 km de raio. Ele foi inicialmente operado em St. Louis, Missouri, e se espalhou rapidamente por 25 cidades (CONRAD, 1959;SCHWARTZ, 2008;RAPPAPORT, 2009). No entanto, os sistemas móveis foram concebidos no final dos anos 40 como sistemas de rádio para despacho de viaturas (bombeiros, policiais, ambulâncias), nos quais um centro de operação de rádio comunicação cobre a região pretendida, em um raio de alguns quilômetros e com um ou mais canais modulados em diferentes frequências, sintonizados pelos rádios portáteis instalados nas viaturas.…”