Driven by expanding scientific questions in cosmology and astrophysics and advances in receiver technology, passive radio astronomy observations now take place over the entire radio spectrum. Active wireless services, including 5G cellular networks, are increasing in spectral occupancy from L band to K band and beyond. Cooperative use of radio spectrum would be improved if observatories had more options for RFI mitigation than blanking and excision and digital domain suppression methods. This project will address technological needs at multiple layers of the passive/active spectral user cooperative space, including dynamically tunable notch filters, analog true-time-delay spatial processing for wideband interference nulling at the system front end, and passive-aware active user network protocols that cooperatively reduce interference for passive radio services. These innovative technologies will be integrated into a demonstrator system to provide a comprehensive and multilayered RFI mitigation strategy for existing and future passive and active spectrum users.
Previous work has been done to retrofit gers so that a electric heater can be used instead of a coal heater. To understand and quantify the efficacy of the ger retrofit solution, we are deploying 50 air quality sensors inside and outside of gers. This will allow us to quantify the impact that the ger retrofit has on the air quality within a ger. By placing sensors outside, we can also determine how well the retrofit is protecting against particulate matter leaking into the structure. Previously collected data has shown that the effects of the retrofit are quite dramatic in reducing the amount of particulate matter in the air inside the ger. We are deploying more sensors for longer time periods to show that this trend is statistically significant. This will prove that the retrofit solution is working as expected and meets specifications.
We design and build a protocol called on-off noise power communication (ONPC), which modifies the software in commodity packet radios to allow communication, independent of their standard protocol, at a very slow rate at long range. To achieve this long range, we use the transmitter as an RF power source that can be on or off if it does or does not send a packet, respectively, and a receiver that repeatedly measures the noise and interference power level. We use spread spectrum techniques on top of the basic on/off mechanism to overcome the interference caused by other devices’ channel access to provide long ranges at a much lower data rate. We implement the protocol on top of commodity WiFi hardware. We discuss our design and how we overcome key challenges such as non-stationary interference, carrier sensing and hardware timing delays. We test ONPC in several situations to show that it achieves significantly longer range than standard WiFi.
This project is part of a University of Utah informatics center awarded through the NIH NIBIB project called Pediatric Research Using Integrated Sensor Monitoring Systems (PRISMS). The goal of our project is to develop systems for smart and healthly homes, including in-home and personal sensors and actuators made to monitor the exposure of residents, to reduce exposures to pollutants, and improve health. A key use case is for pediatric asthma patients.