ATSC Pilot Tone Signaling for Wireless Microphone Protection
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Solution Overview
Problem
Current technologies fail to reliably detect wireless microphone systems in TV Band channels at the stringent sensing threshold set by regulatory bodies, such as the FCC, due to the lack of efficient spectrum sensing mechanisms, leading to potential interference with primary users like digital television broadcasters.
Innovation Solution
A method and system where a wireless microphone system broadcasts a pilot tone within the frequency band designated for an ATSC pilot, allowing TV Band devices to detect its presence, thereby determining channel occupancy and ensuring protection from interfering broadcasts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex receiver/detector capable of detecting spread spectrum beacon signal is equipped in every TV Band device, then wireless microphone detection capability is improved, but device cost increases
Solution Approach 1:
The patent extracts the detection function from a complex spread spectrum beacon detector and implements it through simple energy detection of pilot tones. By taking out only the essential detection capability needed for wireless microphone identification, the system achieves reliable detection without requiring complex receivers in every TV Band device.
Solution Approach 2:
The patent replaces expensive complex spread spectrum detection hardware with inexpensive energy detection circuits. The simple energy detector can reliably identify wireless microphones by detecting pilot tones, providing a cost-effective solution that maintains detection accuracy while dramatically reducing device complexity and cost.
2Reliability
If sensing threshold is set to -114 dBm to protect primary users, then protection capability is improved, but detection reliability of wireless microphones deteriorates
Solution Approach 1:
The patent applies local quality by focusing detection efforts on specific pilot tone frequencies rather than attempting to detect all signals across the entire spectrum at the stringent -114 dBm threshold. By concentrating energy detection on known pilot tone locations, the system achieves reliable wireless microphone detection even at lower signal levels without compromising overall protection capability.
Solution Approach 2:
The patent uses pilot tones as distinctive markers that change the spectral 'color' or signature of wireless microphone transmissions. These pilot tones appear as specific frequency components that stand out from background noise and other signals, enabling reliable detection through energy detection at the pilot tone frequencies without requiring the full -114 dBm sensing threshold across the entire band.
3Measurement precision
If ATSC pilot detection method is used to detect DTV signals, then detection accuracy is improved, but applicability to wireless microphone detection deteriorates
Solution Approach 1:
The patent makes the pilot tone detection method universal by applying the same energy detection technique to both DTV signal detection (ATSC pilot) and wireless microphone detection. The methodology is adapted to detect different types of pilot tones from different sources using the same fundamental approach, enabling a single detection mechanism to serve multiple functions and increase versatility.
Solution Approach 2:
Instead of adapting wireless microphone detection to match DTV detection methods, the patent inverts the approach by making DTV detection adapt to the simpler energy detection method used for wireless microphones. This reversal allows the detection system to use the most appropriate method for each signal type rather than forcing a complex method to handle simpler cases.
Data Source
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AI summary
A wireless microphone system broadcasts a pilot tone at the designated ATSC pilot position in the TV Band channel being used by the wireless microphone system. The pilot tone is a readily detectable waveform transmitted in the ATSC pilot position. The pilot tone can be generated by any one of: a standalone pilot tone generator; a pilot tone generator incorporated into a wireless microphone receiver; or, a pilot tone generator incorporated into a wireless microphone.