Enabling flexible spectrum access (FSA) in existing

wireless networks is challenging due to the limited spectrum

programmability – the ability to change spectrum properties of

a signal to match an arbitrary frequency allocation. This paper

argues that spectrum programmability can be separated from

general wireless physical layer (PHY) modulation. Therefore, we

can support flexible spectrum programmability by inserting a

new spectrum virtualization layer (SVL) directly below traditional

wireless PHY, and enable FSA for wireless networks without

changing their PHY designs.

SVL provides a virtual baseband abstraction to wireless PHY,

which is static, contiguous, with a desirable width defined by the

PHY. At the sender side, SVL reshapes the modulated baseband

signals into waveform that matches the dynamically allocated

physical frequency bands – which can be of different width, or

non-contiguous – while keeping the modulated information unchanged.

At the receiver side, SVL performs the inverse reshaping

operation that collects the waveform from each physical band,

and reconstructs the original modulated signals for PHY. All

these reshaping operations are performed at the signal level and

therefore SVL is agnostic and transparent to upper PHY. We have

implemented a prototype of SVL on a software radio platform,

and tested it with various wireless PHYs. Our experiments show

SVL is flexible and effective

PDF file

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In  IEEE DySpan

Publisher  IEEE

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