Cellular remote antenna feeding: Optical fibre or coaxial cable?

Introduction: It has been shown by Jung and Tonguz [1] that uplinks in personal communication system networks can be built using coaxial cable for link lengths < 0.6 – 1.4km, dependent on the cable loss. Their calculations were performed assuming cables with losses between 30 and 70dB/km at 850MHz. These low values can only be obtained using very expensive low loss cables with diameters > 1/2in. Using such cables, no repeater amplifier is necessary to obtain a reasonable dynamic range [1]. From this point of view, the use of optical fibres is necessary for link lengths > 1.4km. We show that the use of optical fibre is actually justified even for much shorter links. Moreover, it is convenient to use repeater amplifiers and higher loss coaxial cable to minimise the costs of the coaxial link.