Wireless Authentication with Consecutive-Packet CSI Preambles

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Solution Overview

Problem

Existing wireless communication methods for industrial applications face challenges with high latency due to the use of large preambles for channel state information (CSI) authentication, which are not suitable for time-critical industrial environments.

Innovation Solution

A method that utilizes preambles from multiple consecutive packets, each with a short preamble, to perform CSI-based authentication, comparing CSI derived from these packets to a reference, and setting an alarm if deviations exceed a threshold, thereby reducing latency while maintaining security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long preamble is used for CSI-based authentication, then authentication reliability is improved, but communication latency increases

Engineering Contradiction:
Improveauthentication reliabilityVSAvoidcommunication latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the authentication process by using preambles from multiple consecutive packets rather than requiring a single long preamble. Each packet contributes a short preamble segment, and the authentication is performed on the accumulated CSI from these segments across multiple packets, thereby reducing the preamble length requirement for each individual packet while maintaining authentication reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes continuous transmission of multiple packets to accumulate sufficient CSI for authentication. By processing preambles from consecutive packets in sequence, the system maintains continuous useful action for authentication without requiring any single packet to have an excessively long preamble, thus reducing overall latency while ensuring reliable authentication.

Inventive Principle:
Principle #20Continuity of useful action

2Speed

If a short preamble is used to reduce latency, then communication speed is improved, but authentication reliability deteriorates

Engineering Contradiction:
Improvecommunication speedVSAvoidauthentication reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention merges the authentication function across multiple consecutive packets by accumulating CSI from their preambles. Instead of relying on a single short preamble that would be insufficient for reliable authentication, the system combines the CSI information from preambles of multiple packets to achieve both short individual preambles (for low latency) and sufficient authentication reliability through accumulated data.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If CSI-based authentication is implemented, then security against intrusions is improved, but processing complexity increases

Engineering Contradiction:
Improvesecurity against intrusionsVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention leverages the existing CSI estimation process that is already performed for channel decoding in IEEE 802.11g. The same CSI values derived for legitimate channel estimation purposes are reused for authentication, eliminating the need for separate dedicated authentication processing and thereby reducing overall processing complexity while maintaining security.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The CSI estimation process serves multiple functions: it is used for channel decoding to ensure reliable data reception and simultaneously for authentication to detect intrusions. This multi-functionality reduces processing complexity by avoiding duplicate processing steps while enhancing security through the same physical layer measurements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3939348B1Method of authentication of wireless communication based on physical layer security
Publication Date: 2025.07.02 HITACHI ENERGY LTD
  • EP3939348B1 patent drawingFigure 1~2C
  • EP3939348B1 patent drawingFigure 3
  • EP3939348B1 patent drawingFigure 4

AI summary

Communication method (100) using OFDM (Orthogonal Frequency Division Multiplexing) comprising transmitting and receiving packets between a first node and at least one second node, where each packet comprises a preamble and payload data. The method is performed by the first node and comprises: - receiving (114) packets from the at least one second node, and - authenticating (112) the at least one second node based on physical layer characteristics, i.e. on CSI (Channel State Information). Especially, the authenticating (112) is based on a plurality of preambles, which) are extracted from a group of consecutively received packets.