A spread-spectrum system for indoor nonline-of-sight mobile applications

This paper describes a spread-spectrum system designed for indoor wireless applications with no direct path, The key element of the receiver is a diff erential phase shift keying (DPSK) surface acoustic wave (SAW) matched filt er, and its design is described. The excellent performance of such a system is displayed using the case of mobile robotics inside a nuclear plant, Goo d agreement with theoretical results is also illustrated. Finally, we propo se a bandlimited scheme allowing a very simple implementation of diversity with only one DPSK SAW demodulator.