1.6Gb/s Data Throughput Optically-Remoted Leaky Feeders for Underground Transport Environments

In this paper the authors describe a hybrid leaky feeder, fiber-optic transmission system for use in underground transportation networks. The system described has a transmission rate of 1.6 Gb/s and features an ultra wideband, axial-slot leaky feeder, based on standard semi-rigid coaxial cable as a fixed antenna. Patch antennas with a 4 GHz center frequency and 1 GHz, -10 dB bandwidth are proposed for the rolling stock. This highest reported data rate was achieved by combining two 800 Mb/s in-phase and quadrature (I and Q) PSK modulated data streams. A specially designed carrier and data synchronization system provided a convenient interface to a 1.3/1.5 mum diplex single mode fiber-remoting network. The measured 2.4 - 6 GHz leaky feeder bandwidth allows multi-radio, multi-band wireless mesh networking and therefore low-contention gigabit rolling stock data communications.