This paper presents new envelope probability density functions (pdfs) that describe small-scale, local area fading experienced by narrow-band wireless receivers. The paper also develops novel pdfs that describe the local area fading of two specular multipath components in the presence of other diffusely propagating waves. These pdfs are studied in the context of classical fading pdfs such as the Rayleigh, Rician, and other distributions.

No abstract

Backscatter radio systems, including high frequency radio frequency identification (RFID), operate in the dyadic backscatter channel-a two-way pinhole channel that has deeper small-scale fades than that of a conventional one-way channel. This paper shows that pinhole diversity is available in a rich scattering environment caused by modulating backscatter with multiple RF tag antennas-no diversity combining at the reader, channel knowledge, or signaling scheme change is required. Pinhole diversity, along with increased RF tag scattering aperture, can cause up to a 10 dB reduction in the power required to maintain a constant bit-error-rate for an RF tag with two antennas. Through examples, it is shown that this gain results in increased backscatter radio system communication reliability and up to a 78% increase in RF tag operating range.

The single most important factor enabling the data rate increases in wireless networks over the past few decades has been densification, namely adding more base stations and access points and thus getting more spatial reuse of the spectrum. This trend is set to continue into 5G and beyond. However, at some point further densification will no longer be able to provide exponentially increasing data rates. Like the end of Moore's Law, this will have extensive implications on the entire technology landscape, which depends ever more heavily on wireless connectivity. When and why will this happen? How might we prolong this from occurring for as long as possible? These are the questions explored in this paper.

This paper contains measured data and empirical models for 5.85-GHz radio propagation path loss in and around residential areas for the newly allocated U.S. National Information Infrastructure (NII) band. Three homes and two stands of trees were studied for outdoor path loss, tree loss, and house penetration loss in a narrow-band measurement campaign that included 270 local area path loss measurements and over 276 000 instantaneous power measurements. Outdoor transmitters at a height of 5.5 m were placed at distances between 30 and 210 m from the homes, to simulate typical neighborhood base stations mounted atop utility poles. All path loss data are presented graphically and coupled with site-specific information. We develop measurement-based path loss models for propagation prediction. The measurements and models may aid the development of futuristic outdoor-to-indoor residential communication systems for wireless internet access, wireless cable distribution, and wireless local loops.