Wireless Device Secured Communication via Normalized Channel State Information
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Solution Overview
Problem
Establishing secured communication between wireless devices over a wireless channel is challenging due to the risk of unauthorized eavesdroppers intercepting non-secured data, as existing methods fail to maintain secrecy and prevent eavesdroppers from deducing channel information.
Innovation Solution
Wireless devices estimate Channel State Information (CSI) independently and apply a normalization procedure to reduce phase, gain, and timing ambiguities, generating secret keys that match with high probability without exposing CSI over the air, using sounding frames to establish a secured channel that is unique to the communicating devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless devices transmit data over a wireless channel, then communication functionality is enabled, but security against eavesdropping deteriorates
Solution Approach 1:
The patent extracts only the necessary channel characteristics (phase slope, timing offset) from the complete Channel State Information to generate security keys. By taking out only the essential elements needed for security while leaving the rest of the channel information unused for key generation, the system enables secure communication without exposing unnecessary channel details to potential eavesdroppers.
Solution Approach 2:
The patent introduces normalization procedures as an intermediary mechanism between channel estimation and key generation. The normalization process (including phase slope estimation, timing offset compensation, and quantization) acts as a mediator that transforms raw channel measurements into standardized key material, ensuring that both communicating devices derive identical keys while preventing direct exposure of raw channel information.
2Device complexity
If devices independently estimate CSI without normalization, then processing complexity is reduced, but key matching probability deteriorates
Solution Approach 1:
The patent applies preliminary normalization actions to the Channel State Information before using it for key generation. By pre-processing the CSI through phase slope estimation, timing offset compensation, and quantization in a standardized manner, both devices ensure their channel measurements are aligned and comparable, guaranteeing that independent estimations will produce matching keys without requiring complex post-processing reconciliation.
3Productivity
If complete CSI is exposed over the air for key generation, then key generation speed is improved, but information security deteriorates
Solution Approach 1:
The patent extracts only the necessary channel characteristics (phase slope, timing offset) from the complete Channel State Information to generate security keys. By taking out only the essential elements needed for security while leaving the rest of the channel information unused for key generation, the system enables secure communication without exposing unnecessary channel details to potential eavesdroppers.
Data Source
AI summary
A wireless device (24) includes a modem (56) and processing circuitry (50, 52). The modem is configured to modulate signals for transmission over wireless channels, and demodulate signals received over the wireless channels. The processing circuitry is configured to receive a first frame from a second wireless device over a wireless channel via the modem, and transmit a second frame to the second wireless device via the modem over the wireless channel, to calculate a first Channel State Information (CSI) based on the first frame, to calculate a first normalized CSI by applying to the first CSI a normalization procedure, and generate, based on the first normalized CSI, a first key that due to the normalization procedure has an increased likelihood to match a second key generated in the second wireless device based on the second frame, and to communicate securely with the second wireless device over the wireless channel using the first key.