RF Signal Masking via Base-Station Offload for Secure Backscatter
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Solution Overview
Problem
Conventional RF backscattered communication lacks encryption, making data encoded in backscattered signals vulnerable to interception by unintended devices, which is resource-intensive for resource-constrained devices to implement.
Innovation Solution
A secondary communication channel is used by a base station to send a masking signal to a resource-constrained RF device, which mixes the masking signal with a response signal to obfuscate the data, allowing the base station to recover the original signal by filtering out the masking signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption is implemented in RF backscattered communication, then communication security is improved, but device complexity and power consumption increase
Solution Approach 1:
The system divides the encryption function into two separate components: the base station performs the complex masking signal generation and filtering operations, while the resource-constrained RF device only performs simple signal mixing and backscattering. This segmentation allows security enhancement without burdening the limited resources of the backscattered device.
Solution Approach 2:
A masking signal is introduced as an intermediary element that the base station transmits to the RF device. This masking signal acts as a key that enables secure communication without requiring the RF device to implement complex encryption algorithms. The base station filters out this masking signal to recover the original data, while unauthorized devices cannot extract meaningful information.
2Reliability
If encryption is implemented in RF backscattered communication, then communication security is improved, but power consumption increases
Solution Approach 1:
The computational workload for encryption is segmented such that the power-intensive operations (masking signal generation and filtering) are performed at the base station with ample power supply, while the RF device consumes minimal power by only mixing signals and backscattering. This resolves the contradiction between security and power consumption for resource-constrained devices.
Solution Approach 2:
The base station provides the masking signal to the RF device, enabling the RF device to achieve encrypted communication without having to generate or manage its own encryption keys. This self-service approach from the base station eliminates the need for power-intensive cryptographic operations at the RF device.
3Reliability
If masking signal processing is performed at the RF device, then communication security is improved, but processing burden on the resource-constrained device increases
Solution Approach 1:
The signal processing tasks are segmented by capability: the base station handles complex masking signal generation and filtering operations, while the RF device performs only simple mixing and backscattering. This segmentation ensures security enhancement without overwhelming the processing capabilities of the resource-constrained device.
Solution Approach 2:
Instead of having the RF device generate and manage the masking signal (which would burden its limited resources), the approach is inverted: the base station generates and transmits the masking signal to the RF device. This inversion of roles allows secure communication while keeping the RF device's processing burden minimal.
Data Source
AI summary
Examples are disclosed that relate to improving security of radio frequency (RF) backscattered communication. In one example, a RF device includes a primary RF signal receiver, a secondary signal receiver, a signal mixer, and a transmitter. The primary RF signal receiver is configured to receive a RF carrier signal sent from a base station. The secondary signal receiver is configured to receive a masking signal from the base station. The signal mixer is configured to generate a response signal based at least on the RF carrier signal and generate a mixed signal by mixing the response signal and the masking signal. The transmitter is configured to broadcast the mixed signal, via backscattering, as a masked backscattered signal.