Results From COST 235 on Frequency Selective Effects and Bandwidth Csnsiderations

摘要

The Working Group 1 (WG1) of COST Project 235 studied frequency selective effects on digial line-of-sight (LOS) radio links. The transmission capacity if digital links has been increased over the years and seems soon to provide 622 Mbit/s within the same bandwidth as earlier analogue and lower capacity digital systems. Cpmplex modulation schemes are needed to achieve this, but this makes the systems more sensitive to distortion caused yb multipath propagation. It these effects properly into account, and make accurate estimates of diversity reception improvement. The results from WGl include new and refined performance prediction methods that cover all practical aspects of radio links design including diversity protection and dual polarised co-channel operation. New information on clear-air radiocliamtic parameters have also been derived. Finally, some guidelines for predicting outage on Synchronous Digital Hierarchy (SDH) links are provided.