Ranging Sounding Signal Protection via Phase Rotation Encoding
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Solution Overview
Problem
Wireless communication systems face challenges in protecting ranging sounding signals from physical level attacks, where attackers can impersonate devices or interfere with round trip time (RTT) computations to falsely determine distances, leading to inaccurate measurements.
Innovation Solution
Implementing various physical layer protection schemes, such as encoding sounding training signals with phase rotations or cyclic shifts, introducing time delays, and modifying packet structures to prevent attackers from interfering with RTT measurements, including encoding the long training field (LTF) sequence and conveying encoding information in separate fields to ensure secure ranging operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ranging sounding signals are transmitted without encoding protection, then the system maintains simplicity and ease of operation, but the system becomes vulnerable to physical level attacks where attackers can impersonate devices and interfere with RTT computations
Solution Approach 1:
The patent applies preliminary action by encoding the LTF sequence with phase rotations or cyclic shifts before transmission. This pre-encoding ensures that when the ranging sounding signal is transmitted, it already contains protective encoding that prevents attackers from successfully impersonating devices or interfering with RTT computations, thereby resolving the security vulnerability without requiring complex real-time protection mechanisms
Solution Approach 2:
The patent employs parameter changes by modifying the LTF sequence through phase rotations or cyclic shifts. These parameter transformations encode the ranging signal in a way that maintains its functional properties while making it resistant to physical level attacks. The encoded parameters allow the receiver to verify authenticity and compute accurate RTT measurements, thus improving security against attacks while keeping the encoding scheme manageable
2Measurement precision
If encoding information is conveyed in separate fields, then measurement precision is improved by preventing attacker interference, but the packet structure becomes more complex
Solution Approach 1:
The patent applies segmentation by separating the encoded LTF sequence from its encoding information, with each conveyed in distinct fields within the packet structure. This segmentation allows the ranging signal and its protection parameters to be transmitted independently, enabling the receiver to process them separately and verify authenticity, thereby improving RTT measurement accuracy while organizing the increased complexity into manageable, structured components
Data Source
AI summary
Generally, the described techniques provide for protection mechanisms for sounding training signals transmitted between wireless devices when performing ranging sounding estimation. For example, sounding training signals may be encoded to include a sequence of phase rotations or cyclic shifts to protect the sounding training signal from peer devices. In some cases, encoding information associated with a long training field (LTF) may be transmitted either before or after the LTF is transmitted. Additionally or alternatively, a time delay may be introduced to the sounding training signal, where timing information may be removed from one or more fields of the sounding training signal and the time delay may be appended to an interframe spacing. Alternatively, a frame may be split into multiple frames with the sounding training signal in a first frame, and timing information in a second frame that is offset in time from the first frame.