In-Building Wideband Partition Loss Measurements at 2.5 GHz and 60 GHz (1701.03415v1)

Abstract: This paper contains measured data and empirical models for 2.5 & 60 GHz in-building propagation path loss and multipath delay spread. Path loss measurements were recorded using a broadband sliding correlator channel sounder which recorded over 39,000 Power Delay Profiles (PDPs) in 22 separate locations in a modern office building. Transmitters and receivers were separated by distances ranging from 3.5 to 27.4 meters, and were separated by a variety of obstructions, in order to create realistic environments for future single-cell-per-room wireless networks. Path loss data is coupled with site-specific information to provide insight into channel characteristics. These measurements and models may aid in the development of future in-building wireless networks in the unlicensed 2.4 GHz and 60 GHz bands.

• The paper presents a comprehensive analysis of in-building partition loss using over 39,000 power delay profiles across multiple office locations.
• The study employs a broadband sliding correlator and distinct antenna types to contrast propagation characteristics at 2.5 GHz and 60 GHz under realistic conditions.
• Results reveal sharper attenuation and higher spatial reuse at 60 GHz, with significant partition loss variations across materials like drywall and mesh glass.

Analyzing In-Building Wideband Partition Loss at 2.5 GHz and 60 GHz

This paper presents a comprehensive paper of in-building wireless signal attenuation and delay characteristics at 2.5 GHz and 60 GHz frequencies within a modern office building. Given the evolving landscape of wireless communication infrastructure, particularly with the anticipated growth in broadband services, understanding these characteristics is crucial for future network design and deployment.

Methodology and Experimental Setup

The authors employed an extensive measurement campaign using a broadband sliding correlator channel sounder to gather data. Measurements involved the acquisition of over 39,000 power delay profiles (PDPs) across 22 locations on a single floor of a Virginia Tech office building. The setup included varying separation distances between transmitters and receivers and involvement of multiple obstructions to emulate realistic conditions for potential femtocellular networks. Notably, at 60 GHz, pyramidal horn antennas were used due to their higher gain, accommodating the increased path loss at millimeter-wave frequencies, while 2.5 GHz measurements used omnidirectional biconical antennas to mimic typical WLAN system characteristics.

The measurement data were meticulously collected, ensuring high precision through calibrated setups and consistent repeated measures. This helped achieve a high degree of measurement accuracy with minimal deviation, validating the reliability of the results.

Key Findings

The paper found distinct differences in propagation characteristics between the two frequency bands. The 60 GHz band exhibited higher spatial frequency reuse potential, due to sharper attenuation with distance and obstructions, effectively supporting the single-cell-per-room model. The path loss models indicated average exponents of 2.4 for 2.5 GHz and 2.1 for 60 GHz, with standard deviations of 5.8 dB and 7.9 dB, respectively. This difference reflects the more free-space-like propagation behavior observed at 60 GHz when using highly directional antennas.

Partition losses, representing signal attenuation through various building materials, varied significantly between the two frequencies. Attenuation for drywall, whiteboards, and mesh glass notably increased at 60 GHz compared to 2.5 GHz. This suggests that the choice and arrangement of materials in network environments critically impact channel characteristics at different frequencies.

Theoretical and Practical Implications

The empirical models presented advance the understanding of propagation mechanisms in complex indoor environments. Particularly for 60 GHz, partition losses and precise delay spreads suggest potential for high-data-rate applications constrained to single, unobstructed rooms. The detailed breakdown of partition losses underscores the importance of site-specific factors in designing efficient wireless systems, especially at higher frequencies where environmental interactions are more pronounced.

In practical terms, these findings serve as a foundation for simulation and planning tools tailored for femtocellular networks, facilitating the optimization of coverage and throughput in densely populated buildings. They also provide crucial input for ray-tracing algorithms that predict network performance under various building configurations and material utilizations.

Future Prospects

The data and models derived from this paper open avenues for further research on integrating adaptive beamforming and smart antenna technologies with the propagation constraints observed, especially at 60 GHz. As wireless networks evolve, leveraging such detailed empirical insights could significantly enhance system capacities and reliability within indoor environments.

Overall, the paper provides a rigorous examination of in-building wireless propagation characteristics at 2.5 GHz and 60 GHz. The findings bridge a vital knowledge gap, aiding the development of the next generation of wireless communications systems, tailored to the material and structural variations typical of modern buildings.