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Passive Remote Sensing services are indispensable in modern society because of the applications related to climate studies and earth science. Among those, NASA’s Soil Moisture Active and Passive (SMAP) mission provides an essential climate variable such as the moisture content of the soil by using microwave radiation within protected band over 1400-1427 MHz. However, because of the increasing active wireless technologies such as Internet of Things (IoT), unmanned aerial vehicles (UAV), and 5G wireless communication, the SMAP’s passive observations are expected to experience an increasing number of Radio Frequency Interference (RFI). RFI is a well-documented issue and SMAP has a ground processing unit dedicated to tackling this issue. However, advanced techniques are needed to tackle the increasing RFI problem for passive sensing systems and to jointly coexist communication and sensing systems. In this paper, we apply a deep learning approach where a novel Convolutional Neural Network (CNN) architecture for both RFI detection and mitigation is employed. SMAP Level 1A spectrogram of antenna counts and various moments data are used as the inputs to the deep learning architecture. We simulate different types of RFI sources such as pulsed, CW or wideband anthropogenic signals. We then use artificially corrupted SMAP Level 1B antenna measurements in conjunction with RFI labels to train the learning architecture. While the learned detection network classifies input spectrograms as RFI or no-RFI cases, the mitigation network reconstructs the RFI mitigated antenna temperature images. The proposed learning framework both takes advantage of the existing SMAP data and the simulated RFI scenarios. Future remote sensing systems such as radiometers will suffer an increasing RFI problem and spectrum sharing and techniques that will allow coexistance of sensing and communication systems will be utmost importance for both parties. RFI detection and mitigation will remain a prerequisite for these radiometers and the proposed deep learning approach has the potential to provide an additional perspective to existing solutions. We will present detailed analysis on the selected deep learning architecture, obtained RFI detection accuracy levels and RFI mitigation performance.
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Opportunistic Temporal Spectrum Coexistence of Passive Radiometry and Active Wireless Networks
There is insufficient wireless frequency spectrum to support the continued growth of active wireless technologies and devices. This has provoked extensive research on spectrum coexistence. One case that has gained limited attention in this course is using currently banned frequency bands for active wireless communications. One such option is the 27 MHz-wide narrowband portion of the L-band from 1.400 to 1.427 GHz, which is exclusively devoted to space-borne passive radiometry for remote sensing and radio astronomy. Radio regulations currently prohibit active wireless communications and radars from operating in this band to avoid radio frequency interference (RFI) on highly noise-sensitive passive radiometry equipment. The National Aeronautics and Space Administration’s (NASA’s) Soil Moisture Active Passive (SMAP) satellite is one of the latest space-borne remote sensing missions that evaluates global soil moisture by passive scanning of the thermal emissions of the earth in this frequency band. In this paper, we investigate the opportunistic temporal use of this 27 MHz-wide passive radiometry band for active wireless transmissions when there is no Line of Sight (LoS) between SMAP and a terrestrial wireless network. We use MATLAB simulations to determine the fraction of time that SMAP has LoS (and non-LoS) with a terrestrial wireless cell at different Earth latitudes based on SMAP’s orbital characteristics. We also investigate the severity of RFI induced on SMAP in the presence of a terrestrial cluster of 5G cells with LoS.
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- Award ID(s):
- 2030157
- PAR ID:
- 10464588
- Date Published:
- Journal Name:
- 2022 IEEE Western New York Image and Signal Processing Workshop (WNYISPW)
- Page Range / eLocation ID:
- 1 to 4
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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We consider the uplink of a large-scale active terrestrial cellular network operating in the restricted L-band (1400–1427 MHz) with NASA's Soil Moisture Active Passive (SMAP) satellite. In our previous work, we used stochastic geometry to derive the statistical properties of radio frequency interference (RFI) at SMAP that originates from the terrestrial network. We demonstrated that, while it is crucial to prevent RFI from interfering with the main-lobe of SMAP's antenna, its low-gain side-lobe can tolerate the coexistence of a significant number of active devices on the same channel with low to moderate RFI impact on SMAP's measurements, ensuring minimal disruption to its sensing accuracy. In this paper, we extend our previous work by analyzing the Sensing Outage Probability (SOP), which is a novel metric that represents the probability of RFI exceeding the acceptable error threshold for a given passive remote sensing mission. We specifically assess the statistical characteristics, namely, the expected value and variance, of RFI induced on the SMAP satellite by clusters of 5G cellular User Equipment (UE), considering variations in the number of UEs and their transmission powers. Subsequently, we derive the SOP for each configuration and demonstrate that a significant number of UEs can operate co-channel with the passive remote sensor while ensuring that the induced RFI remains below a given threshold (in Kelvin) with high certainty.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Conference Paper:
- https://doi.org/10.1109/WNYISPW57858.2022.9983493
