Evaluating pay-telephone service on coastal ferries

摘要

Reports the statistical results of RMS delay spreads obtained from the impulse response measurements on the propagation channels of two ferry routes. Some interesting impulse responses measured as the ferry was passing through regions where multipath echoes are known to be very active are also presented. The two ferry routes measured were F2 and F1 in Vancouver. Route F2 runs from Horseshoe Bay to Nanaimo, at a distance of 30 miles and a crossing time of 1 hr and 35 min. At both ends of route F2, the line-of-sight paths were obstructed by islands, and multipath signals were very active. Route F1 runs from Tsawwassen to Swartz Bay, at a distance of 24 miles and a crossing time of 1 hr and 35 min. In the region between Galiano Island and Swartz Bay, the ferry crisscrosses many islands. In this region, multipath signals are extremely active. The channel impulse response measurements were made with a spread spectrum channel sounder at a frequency of 916 MHz. A chip rate of 3.125 Mb/s, a PN code word length of 127 bits, and a slip rate of 1 kHz were used The minimum time resolution was 0.32 mu s, and the maximum measurable relative delay was 40.64 mu s. Complete measurement for one complete round trip on each route was performed, and collected data was processed. Results indicate that at a threshold of -20 dBc, RMS delay spread of 10 mu s and 12 mu s were exceeded 10% of the time for routes F2 and F1, respectively.