700-MHz Channel Propagation Models
Project Description
SNAPSHOT
Omnidirectional antennas are used for the TX and RX antennas for frequencies in the 700-MHz band. Frequency response of the channel is measured using a VNA.
The conversion from analog television in the United States, combined with the appeal for broadband pubic safety communications, has generated a lot of interest in the 700 MHz broadband spectrum. The 764- to 776-MHz and 794- to 806-MHz blocks have been dedicated to public safety while the others have been auctioned off to vendors for commercial services, and some blocks for joint use between the two.
The 700-MHz band offers excellent penetration through buildings, which is particularly useful for emergency responders and E911 services. Favorable propagation characteristics, which extend coverage significantly for the same transmission power—translating into less infrastructure—motivates commercial investment in the 700-MHz band.
BACKGROUND
To help develop and deploy network technology in the 700-MHz band, the PSCR program has performed propagation measurements to characterize and understand the 700-MHz broadband environment in which future public safety communications will operate. In this effort we have derived propagation models from measurement campaigns conducted in the following eight environments.
| 1. Republic Plaza Building, Denver, CO | 5. Horizon West apartment, Boulder, CO |
| 2. Denver Convention Center, Denver, CO | 6. Oil refinery, Commerce City, CO |
| 3. Hazel-Atlas subterranean mine tunnel, Antioch, CA | 7. NIST laboratory, Boulder, CO |
| 4. Greathouse subterranean mine tunnel, Antioch, CA | 8. Downtown urban canyon, Denver, CO |
AN INNOVATIVE APPROACH
PSCR based its 700-MHz channel propagation models on measurements collected by the NIST Radio Frequency Fields Group. Details of the measurements can be found in the following reports:
Attenuation of Radio Wave Signals Coupled Into Twelve Large Building Structures
Measurements to Support Broadband Modulated-Signal Radio Transmissions for the Public-Safety Sector
VALUE TO PUBLIC SAFETY
The PSCR program’s 700-MHz channel propagation work provides telecommunications designers working in public safety communications with models to use in simulation and testing.
RESULTS
The propagation measurements resulted in two 700-MHz channel propagation models.
- The first model covers the first seven environments listed in Background above. A full description of the stochastic model is provided in this paper: A Channel Propagation Model for the 700 MHz Band
Frequency and impulse responses can be generated from the model in any of the seven environments in MATLAB through this file: Channel_response_generator.m.
The input parameters are transmitter-receiver distance (m), bandwidth (GHz) and center frequency (GHz), maximum display time of the impulse response (ns), and the environment (specified as a number 1-7).
In addition, this firefighter demo shows video footage of the packet loss using the model during a transmission through three of the environments: Firefighter video demo in three environments.
- The second model covers the urban canyon environment listed in Background above. It differs from the model in that an antenna array was used on the receiver end (as opposed to a single element), which allowed modeling the impulse response in the spatial domain as well as in the temporal domain. A paper providing a full description of the model is currently under peer review.
This firefighter demo shows video footage of the packet loss using the model during a transmission on site where the measurement campaign was actually conducted: Firefighter video demo in Downtown Denver.
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Right-click 700-MHz Channel Propagation Models to save or download this one-page project summary PDF file. Click here for more detailed resources concerning this project. See also, Broadband Press.
For more information, contact: Nada Golmie.
