Measurements to Support Modulated-Signal Radio Transmissions for the Public-Safety Sector; Technical note

摘要

This is the fifth in a series of NIST Technical Notes (TN) on propagation and detection of radio signals in large building structures. This series has been developed to support improved radio communications for the public-safety community in difficult radio environments. The first, second and third NIST Technical Notes (NIST TN 1540, 1541, and 1542) described experiments that measured received signal strength in structures before, during, and after implosion. The fourth, NIST Technical Note 1545, describes a series of signal-strength measurements carried out in 14 large public buildings. The first four Technical Notes have created a large, public-domain data set describing the attenuation of radio signals in various building types for the public safety and cellular telephone bands. The present document augments this work by providing additional data that are relevant to modulated-signal communication measurement and simulation for the public-safety sector. We describe measurements of three large public buildings and one subterranean tunnel. Wireless communication using wideband digitally modulated signals propagating into and out of large buildings and other structures is complicated by several factors, including the strong attenuation of radio signals caused by losses in the building materials, scattering from structural features (multipath), and waveguiding effects of corridors and tunnels. Understanding the losses and their variability, decay times for reflected signals, the frequency-selective behavior of the channel, and the combined effect these have on broadband digitally modulated signals can help system engineers assess various technologies.