This article describes the development of optimised radiating cables for GSM retransmission in tunnels. It demonstrates theoretically the feasibility of a GSM confined area radio station using a booster station approach. It also explores the potential advantage of using a fibre optic backbone to directly feed the transmission equipment. Two different cables were optimised for the tunnel application. The VARIO type cable is shown to be the best option. New formulae were derived for the system design. These computed the signal-distortion ratios of an optimised cascaded and branched system.
Abstract