h new methods in sharing of spectrum resources among multiple ser- vices in a way that certain QoS levels could be guaranteed. This scheme could potentially allow for availability of new spectrum licensed to incumbents (e.g. government agencies, satellite systems, Electronic New Gathering [ENG], amateur radio, and many others) for cellular communications without impacting the operation of the incumbent systems. It also technology-neutral approach to paired bands, therefore, takes the form of allowing any duplexing scheme in the paired spectrum, e.g. uplink/downlink (UL/DL), downlink/uplink, (DL/UL), or time division duplex/time division duplex (TDD/TDD). 2 Market Drivers Figure 2.6 Spectrum sharing. Dedicated Shared Licensed Spectrum Spectrum improves overall spectrum utilization while providing some assurance to the licensees that they will get Return on Investment (ROI) on a network build-out using that spectrum. This is illustrated by Figure 2.6. One of the first spectrum-sharing cases was the TV White Spaces (TVWS). TVWS allows unlicensed, secondary devices to access spectrum licensed to broadcasting at specific loca- tions and time intervals, where they would not interfere with the operation of the incum- bent systems. Unfortunately, TVWS technology adoption levels remain low. Two new spectrum-sharing frameworks have been developed: LSA developed by the European Telecommunications Standards Institute (ETSI) and the European Conference of Postal and Telecommunications Administrations (CEPT) in Europe, and CBRS developed by CBRS Alliance in the US. These initiatives show great promise and at the time of writing of this book a number of companies had applied for the CBRS license and started testing CBRS networks. The Federal Communications Commission is expected to start auctioning the Priority Access License (PAL) part of the CBRS band by 2020. Even though CBRS and LSA are conceptually similar, there are certain differences in how these technologies will be implemented, as summarized in Table 2.2. In CBRS, the