A robust SAW-based chirp-/spl pi//4 DQPSK system for indoor applications

A high data-rate wideband chirp spread spectrum system for indoor communication is proposed. The use of chirp signals with the well known pulse compression technique makes the system extremely robust and therefore suitable for applications in an industrial environment. By using /spl pi//4 DQPSK modulation, overlapping chirp signals, and optimized chirp signal design we get data rates up to 70 Mbps. There is no need for sophisticated digital signal processing due to the use of surface acoustic wave (SAW) filters for the generation and filtering of the chirp signals. Production tolerances, temperature drift, and other system imperfections are shown to be either negligible or can easily be tracked. Simulation results reveal that the limiting factor for the data rate is intersymbol interference caused by multipath propagation.