Hardware-Free Same-Channel Spectrum Sensing for UAS C2 Radios
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Solution Overview
Problem
Existing unmanned aircraft systems (UAS) face challenges in managing spectrum resources efficiently due to self-interference from careless spectrum reuse, which can lead to congestion and capacity issues, and adding hardware-based sensors is impractical under size, weight, and power restrictions.
Innovation Solution
Implementing a software-based spectrum sensing method within the command and control (C2) link system using same-channel out-of-band sensing during idle times to identify available frequencies, determining interference levels, and communicating these to a centralized spectrum arbitrator for management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware-based spectrum sensors are added to every ARS and GRS, then spectrum sensing capacity is improved, but device complexity and weight increase
Solution Approach 1:
The existing C2 communications device is made multi-functional by enabling it to perform both communications and spectrum sensing functions. The device uses its existing receiver to detect both C2 signals and spectrum signals, eliminating the need for separate dedicated sensing hardware while maintaining sensing capacity.
Solution Approach 2:
The C2 communications device performs spectrum sensing for itself and the network using its own built-in receiver capabilities. By utilizing idle reception periods during which it would otherwise be inactive, the device serves dual purposes without requiring additional dedicated sensing resources.
2Measurement precision
If hardware-based spectrum sensors are added to every ARS and GRS, then spectrum sensing capacity is improved, but weight increases
Solution Approach 1:
The existing C2 communications device is made multi-functional by enabling it to perform both communications and spectrum sensing functions. The device uses its existing receiver to detect both C2 signals and spectrum signals, eliminating the need for separate dedicated sensing hardware while maintaining sensing capacity.
Solution Approach 2:
The C2 communications device performs spectrum sensing for itself and the network using its own built-in receiver capabilities. By utilizing idle reception periods during which it would otherwise be inactive, the device serves dual purposes without requiring additional dedicated sensing resources.
3Productivity
If spectrum resources are reused more aggressively to increase capacity, then system capacity is improved, but self-interference increases
Solution Approach 1:
The system implements feedback mechanisms where C2 communications devices report detected interference levels and spectrum conditions back to the network. This enables dynamic spectrum resource allocation and adjustment, allowing the system to optimize capacity while maintaining interference thresholds through continuous monitoring and adaptive management.
Solution Approach 2:
The system performs preliminary spectrum sensing and interference detection before allocating spectrum resources. By proactively identifying potential interference conditions and establishing baseline measurements, the network can make informed decisions about spectrum reuse that prevent harmful self-interference before it occurs.
Data Source
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AI summary
A command and control (C2) radio system configured for same-channel out-of-band sensing is disclosed. In embodiments, the radio system (e.g., an air radio system (ARS) aboard an unmanned aircraft system (UAS) or a ground radio station (GRS)) scans its switching back to the appropriate operating frequency before the next subframe starts. The radio system processes the collected energy samples to determine minimum and mean operating frequencies for idle subframes and slots where a preamble is not detected. The radio system uses idle frames to scan sensing frequencies assigned by a central server of the C2 link system, collecting spectral energy sources during the idle timeslots and energy levels, thereby identifying the level of interference on the assigned frequency (e.g., due to noise or interfering signals) and hypothesizes whether the detected interference is tolerable or precludes current use of the assigned signal in the vicinity of the radio system.