Towards a virtual cellular network with variable grade spectrum: challenges and opportunities

In this paper, we make a case for future wireless networks that will seamlessly exploit many variable grade spectrum bands. The transformation we envision will be fueled by a fundamental change in the way networks use spectrum. The mix of spectrum options will include existing exclusively licensed and unlicensed bands and new shared spectrum bands where incumbent primary transmitters with interruptible, exclusive access share the band with cooperating (secondary) users. Such bands used in small cell deployments will be key to creating enormous wireless capacity needed to support future traffic demands. The nascent spectrum database technologies will morph into more dynamic spectrum databases and provide essential interference coordination, channel management and monetization. This trend when combined with infrastructure sharing enabled by cloud and SDN technologies will gradually lead to new deployment models. Such network transformation and democratization of spectrum access can fuel innovative business models and new regulatory regimes for wireless networks. We illustrate the new architecture and component radio, database and security technologies using concrete example of incorporating shared spectrum in a small cell network.