Physical Layer Security for Positioning Reference Signals
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Solution Overview
Problem
Current wireless communication systems, particularly in the context of 5G, face challenges in securing positioning reference signals (PRS) from frequency-domain symbol-level attacks, where attackers can decode and replicate PRS, compromising security and accuracy.
Innovation Solution
Implementing physical layer security measures such as on-demand PRS transmission with specific security properties, including comb-N density, CP-OFDM waveform, and M-PSK modulation, using secret keys to modify PSK constellations, and incorporating random noise in unused resource elements to prevent attackers from decoding PRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PRS transmission uses standard formats (comb-N density, CP-OFDM waveform, M-PSK modulation), then positioning accuracy is maintained, but security against frequency-domain attacks is compromised
Solution Approach 1:
The patent modifies physical layer parameters of PRS transmission by changing the waveform from CP-OFDM to DFT-s-OFDM, adjusting modulation schemes, and altering resource element mapping patterns. These parameter changes maintain positioning functionality while introducing characteristics that resist frequency-domain symbol-level attacks, directly resolving the contradiction between standard format compatibility and security against attacks.
Solution Approach 2:
The patent employs composite signaling structures that combine multiple PRS formats with different security properties. By transmitting PRS using diversified waveforms and modulation schemes within the same system, it creates a composite transmission approach where some formats provide positioning accuracy while others provide security against frequency-domain attacks.
2Object-affected harmful factors
If on-demand PRS transmission with security properties is implemented, then security against attacks is improved, but system complexity increases
Solution Approach 1:
The patent implements dynamic PRS transmission where the network entity selectively activates security-enhanced PRS formats based on detected attack conditions. The system transitions between standard and secure modes dynamically, adjusting transmission parameters in real-time based on threat levels, thereby managing complexity through conditional activation rather than permanent implementation.
Solution Approach 2:
The patent applies security properties locally to specific PRS resources rather than uniformly to all transmissions. By selectively applying security measures to vulnerable PRS instances while maintaining standard formats for non-vulnerable transmissions, the system reduces overall complexity while providing targeted security where needed.
3Object-affected harmful factors
If random noise is added to unused resource elements, then attacker's ability to decode PRS is reduced, but signal quality may deteriorate
Solution Approach 1:
The patent applies random noise masking selectively to unused resource elements (null REs) rather than to the entire PRS signal. This localized application of noise provides security against decoding attacks while preserving the integrity and quality of the actual PRS components, resolving the contradiction between security and signal quality.
Data Source
AI summary
Disclosed are techniques for wireless positioning. In an aspect, a network node transmits, to a network entity, a request for transmission of one or more first positioning reference signals (PRS) resources having one or more physical layer security properties, and measures the one or more first PRS resources having the one or more physical layer security properties. In an aspect, a network entity receives, from a first network node, a request for transmission of one or more first positioning reference signals (PRS) resources having one or more physical layer security properties, and transmits, to a second network node, a request for the second network node to transmit the one or more first PRS resources having the one or more physical layer security properties to the first network node.