Jamming Detection Using Synchronization Channel Correlation
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Solution Overview
Problem
Current anti-jamming solutions for CDMA-based radio networks are inadequate as they rely heavily on sophisticated signal strength and power measurements, which are unreliable and prone to false negatives, especially in environments with frequent intercell and intercell interferences, making it difficult to distinguish between normal frequency disturbances and external jamming.
Innovation Solution
A method and device that detect jamming by testing the match of a uniform synchronization signal sequence of the synchronization channel and comparing the power indicator to a noise floor threshold, providing a Boolean indication of a jamming situation without relying on complex power level comparisons, ensuring the user equipment can communicate in a CDMA-based network by verifying the detectability of the synchronization channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If sophisticated signal strength and power measurements are used for jamming detection, then the detection capability is improved, but the reliability deteriorates due to false negatives in environments with frequent intercell and intracell interferences
Solution Approach 1:
The patent segments the jamming detection process into two independent parts: (1) detecting whether a synchronization channel is present using correlation with a known synchronization sequence, and (2) measuring the total received power level. This segmentation allows each part to perform its specialized function optimally without interference from the other, resolving the contradiction between detection capability and reliability.
Solution Approach 2:
The patent introduces an intermediary indicator variable that records the presence or absence of a synchronization channel separately from the power measurement. This intermediary allows the system to combine both pieces of information logically (presence of sync channel AND power above threshold) to make a reliable jamming detection decision, avoiding false negatives that occur when relying on power measurements alone in high-interference environments.
2Measurement precision
If complex power level comparisons are used for jamming detection, then the detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the synchronization channel detection function from the overall jamming detection system. By using a known synchronization sequence and correlation technique, the system can detect the presence of a valid synchronization channel without needing to perform complex power level comparisons or analyze the full signal structure. This extraction simplifies the device while maintaining detection accuracy.
Solution Approach 2:
The patent changes the detection parameter from complex power level comparisons to a binary presence/absence indicator of the synchronization channel. Instead of comparing multiple power levels and making complex decisions, the system simply checks whether the correlation result indicates a valid synchronization channel is present, combined with a simple power threshold check. This parameter change reduces device complexity while preserving detection accuracy.
3Reliability
If synchronization channel detectability is used for jamming detection, then false alarms are reduced, but the measurement precision requirements increase
Solution Approach 1:
The patent performs preliminary synchronization channel detection before making the final jamming detection decision. By first checking whether a valid synchronization channel is present using correlation with the known synchronization sequence, the system eliminates false alarms that would occur from power measurements alone. This preliminary action establishes a reliable baseline that must be satisfied before considering the power level threshold.
Solution Approach 2:
The patent replaces complex mechanical signal analysis with a mathematical correlation operation. Instead of using sophisticated signal processing hardware to measure and compare power levels with high precision, the system uses a simple correlation calculation between the received signal and the known synchronization sequence. This substitution reduces the precision requirements of the measurement system while improving reliability.
Data Source
AI summary
A method of detecting a jamming transmitter includes the steps of indicating that a communication user equipment is capable of communicating in a cellular code division multiple access based radio network; testing a match of a uniform synchronization signal sequence of a synchronization channel; detecting a power indicator indicative of an unbiased wide band power of a received radio signal strength and comparing the power indicator to a noise floor threshold; and indicating a jamming affection of the communication user equipment in the case where (i) the communication indication is on hold; and (ii) the uniform synchronization sequence of the synchronization channel is not matched in the test, and (iii) the power indicator exceeds the noise floor threshold.