Spectrum Virtualization Layer for White Space Frequency Mapping
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Solution Overview
Problem
Conventional media access control and physical layer protocols are not equipped to handle variable and non-contiguous frequency transmissions required for white space frequency bands, limiting their use in wireless networking.
Innovation Solution
A spectrum virtualization layer that reshapes transmission symbols from a virtual baseband to a physical baseband by performing fast Fourier transforms, mapping frequency components to sub-carriers, and adjusting bandwidth and sampling rates, allowing conventional protocols to operate on non-contiguous and variable white space frequency bands without modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional media access control and physical layer protocols are used, then protocol simplicity and ease of operation are maintained, but the ability to support variable and non-contiguous frequency transmission is lost
Solution Approach 1:
A spectrum virtualization layer is introduced as an intermediary between the physical layer and higher layers. This layer performs signal reshaping operations including fast Fourier transform, frequency component mapping to sub-carriers, and inverse fast Fourier transform to convert signals from virtual baseband to physical baseband. This intermediary handles the complexity of variable and non-contiguous frequency support, allowing conventional protocols to remain simple while adapting to white space frequency bands
Solution Approach 2:
The spectrum virtualization layer segments the frequency spectrum into multiple sub-carriers and selectively maps frequency components to available non-contiguous frequency portions. By dividing the virtual baseband signal into frequency components and selectively assigning them to available physical frequency slots, the system supports non-contiguous transmission while maintaining protocol simplicity
2Adaptability or versatility
If signal reshaping operations are performed to adapt to white space frequency bands, then frequency band adaptability is improved, but processing complexity and computational requirements increase
Solution Approach 1:
The patent replaces traditional mechanical frequency tuning mechanisms with digital signal processing operations. The spectrum virtualization layer uses fast Fourier transform and inverse fast Fourier transform algorithms to perform frequency domain manipulations, substituting mechanical frequency adjustment with computational methods that provide finer control and adaptability to variable white space frequency bands
Solution Approach 2:
The system dynamically changes signal parameters including sampling rate, bandwidth, and frequency mapping configuration to adapt to available white space frequency bands. The spectrum virtualization layer adjusts these parameters based on spectrum availability information, enabling flexible adaptation to different frequency conditions while managing processing complexity through efficient algorithm selection
Data Source
AI summary
Embodiments include processes, systems, and devices for reshaping virtual baseband signals for transmission on non-contiguous and variable portions of a physical baseband, such as a white space frequency band. In the transmission path, a spectrum virtualization layer maps a plurality of frequency components derived from a transmission symbol produced by a physical layer protocol to sub-carriers of the allocated physical frequency band. The spectrum virtualization layer then outputs a time-domain signal derived from the mapped frequency components. In the receive path, a time-domain signal received on the physical baseband is reshaped by the virtual spectrum layer in order to recompose a time-domain symbol in the virtual baseband.