Secure Ranging Using Random Sequence Waveforms and Phase Tracking
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Solution Overview
Problem
Wireless communication systems using predictable structures are vulnerable to attacks that disrupt secure time of flight (SToF) measurements, particularly at higher frequency bands and in non-line of sight (NLOS) scenarios, leading to inaccurate range calculations and security issues.
Innovation Solution
Implementing a flexible protocol with phase tracking and signaling to mitigate phase noise, using zero-padded random sequence waveforms, and determining various antenna weight vector modes to support secure channel estimation and consistency checks, thereby protecting against replay attacks and ensuring accurate SToF measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If predictable and repetitive structures (e.g., CP-OFDM or CP-SC) are used for wireless communication, then ease of operation and compatibility are improved, but vulnerability to attacks and measurement accuracy deteriorate
Solution Approach 1:
The patent changes the fundamental parameter of the waveform structure from predictable/repetitive to random/unpredictable. Specifically, it uses random sequences instead of standard CP-OFDM or CP-SC structures, and employs zero-padding techniques to maintain signal integrity while preserving randomness. This parameter change directly addresses the security vulnerability by making the signal unpredictable to attackers while still enabling legitimate devices to process it through the defined random sequence generation and correlation methods.
2Measurement precision
If channel estimation based on pilots is used for ToA derivation, then measurement capability is improved, but vulnerability to adversarial attacks worsens
Solution Approach 1:
The patent extracts and removes the vulnerable repetitive structure components from the signaling waveform. Instead of using standard pilot-based channel estimation with predictable patterns, it extracts only the necessary channel estimation functionality and implements it through random sequences that are processed via correlation. This extraction eliminates the attack surface associated with predictable structures while preserving the essential measurement capability.
3Productivity
If secure ranging is implemented at higher frequency bands (e.g., 60 GHz), then communication capacity is improved, but phase noise and measurement accuracy deteriorate
Solution Approach 1:
The patent applies preliminary phase tracking and compensation actions before the actual time of flight measurement is performed. By pre-tracking and correcting phase variations using the random sequence correlation process, the system eliminates phase noise effects before they can degrade the measurement. This preliminary action allows high-frequency communication to maintain both its capacity advantage and measurement precision.
4Adaptability or versatility
If legacy 802.11 devices are allowed to coexist in the same frequency bands, then adaptability is improved, but interference and measurement accuracy worsen
Solution Approach 1:
The patent introduces random sequences as an intermediary between the secure ranging system and the legacy 802.11 environment. These random sequences serve as a mediator that allows the secure ranging measurements to proceed without being affected by legacy device transmissions. The randomness acts as a natural filter, allowing the correlated processing to distinguish secure ranging signals from legacy interference, thereby enabling coexistence while maintaining measurement accuracy.
Data Source
AI summary
Some embodiments enable secure time of flight (SToF) measurements for wireless communication packets that include secure ranging packets with zero padded random sequence waveforms, including at higher frequency bands (e.g., 60 GHz) and in non-line of sight (NLOS) scenarios. Some embodiments provide a flexible protocol to allow negotiation of one or more security parameters and/or SToF operation parameters. For example, some embodiments employ: phase tracking and signaling to support devices with phase noise constraints to mitigate phase noise at higher frequencies; determining a number of random sequences (RSs) used for SToF to support consistency checks and channel verification; additional rules supporting sub-phases of the SToF operation; and/or determining First Path (FP), Sub-Optimal, and/or Hybrid path AWV modes and the pre-conditioning usage of these modes.