Secure WLAN Communication via Spatial Power Allocation
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Solution Overview
Problem
In wireless local area networks (WLANs), existing secure communication methods are inadequate as signals can be easily intercepted by unauthorized parties due to the isotropic propagation of signals, even with beamforming and spatial division multiple access (SDMA) techniques, which do not sufficiently degrade the signal-to-noise ratio (SNR) for unintended recipients.
Innovation Solution
Implementing a method that uses a precoding matrix with beamforming vectors and orthogonal noise dither sequences to degrade the SNR for potential interceptors while maintaining a desired quality of service for intended recipients, by allocating power to ensure that the signal power received by intended stations is not more than a predefined margin, and distributing remaining power to orthogonal noise channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If beamforming and SDMA techniques are used to direct signals to intended recipients, then signal directionality and network coverage are improved, but the signal-to-noise ratio for unintended recipients is not sufficiently degraded, allowing interception
Solution Approach 1:
The patent applies local quality by transmitting different signal characteristics to different spatial locations. The precoding matrix distributes power selectively: intended recipients receive signals with sufficient power for reliable decoding, while unintended recipients experience degraded signal-to-noise ratio due to the orthogonal noise dither sequences and power allocation strategy, making interception difficult without compromising legitimate communications
Solution Approach 2:
The patent changes the signal parameters by introducing orthogonal noise dither sequences and adjusting power allocation dynamically. The precoding matrix modifies the amplitude and phase of signals transmitted from multiple antennas, transforming the isotropic propagation pattern into a controlled spatial distribution where signal quality varies by location, thereby degrading intercepted signals while maintaining legitimate communications
2Area of stationary object
If maximum power output is transmitted to increase network coverage, then communication range is improved, but signals become easily detectable by unauthorized parties
Solution Approach 1:
The patent implements local quality by creating spatially varying signal characteristics through the precoding matrix. Network coverage is maintained across the desired area, but the signal quality (power distribution) varies locally: intended recipients experience sufficient signal strength for reliable communication, while unintended recipients encounter degraded signal-to-noise ratio due to the orthogonal noise components and selective power allocation, preventing easy detection and interception
Solution Approach 2:
The patent introduces orthogonal noise dither sequences as an intermediary element. These noise sequences are embedded in the transmitted signal through the precoding matrix and act as a mediator that degrades the quality of intercepted signals. The noise sequences do not affect intended recipients who can decode the original message but make intercepted signals difficult to detect and decode by unauthorized parties
3Reliability
If power is allocated to maximize signal quality for intended recipients, then quality of service is improved, but remaining power distribution may improve interceptor's ability to detect signals
Solution Approach 1:
The patent converts the remaining power that would otherwise be wasted or potentially harmful into a beneficial security feature. By distributing remaining power to orthogonal noise dither sequences through the precoding matrix, the system transforms excess power into a protective mechanism that degrades intercepted signals. This ensures that while intended recipients receive optimal signal quality, unintended recipients experience degraded signal-to-noise ratio, converting potential vulnerability into a security advantage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the likelihood of unintended recipients decoding secure transmissions by degrading the SNR for interceptors while maintaining transmission quality for intended recipients, thereby enhancing communication security in WLANs.
Implementation Method 1
beamforming may allow a collection of omni-directional simple antennas to act like a single, highly focused, directional antenna
Implementation Method 2
the assignment of different amplitudes and phases to simultaneous transmissions from the multiple antennas can create a wave interference pattern which combines coherently at a desired location to reproduce the intended signal
Data Source
AI summary
Some demonstrative embodiments of the invention include a method device and/or system of secure communication in a wireless network using a spatial division multiple access transmission scheme. The method, according to some demonstrative embodiments may include allocating transmission power to N channels to be transmitted to one or more destination stations by N antennas, such that the power to be received by each one of the one or more destination stations is not greater, by more than a predefined power margin, than a minimum power required for reception at a desired quality of service. Other embodiments are described and claimed.