Shared Spectrum On Many Levels is Coming
Federated Wireless and Alphabet have demonstrated interoperability between their respective spectrum access systems (SAS). The SAS is the key enabler of shared spectrum allocation at the heart of the Citizens Broadband Radio Service (CBRS).
The 3.5 GHz CBRS is a revolutionary approach to increasing the supply of communications spectrum, protecting the rights of licensed spectrum owners while also enabling use of such spectrum by sub-licensees, or on a best-effort basis in other cases.
The CBRS will mean an additional 150 MHz of spectrum can be made available to new communications users and applications without the costly relocation of existing users to allow shared use by new commercial entities.
In principle, spectrum sharing will make possible a wider use of existing communications spectrum, allowing present licensees priority access, while also allowing secondary licensees access to unused or lightly-used spectrum, as well as supporting unlicensed, best effort access when primary or secondary users do not require use of the assets.
Such dynamic spectrum allocation mechanisms are quite new, as traditional allocation mechanisms were highly static, giving exclusive use to some licensees, whether that spectrum was used, or not, and often specifying what applications could be run, and just as often what platforms could be employed.
As spectrum in the low and mid-bands remains relatively scarce, dynamic allocation will improve the efficiency and intensiveness of use of those assets.
The other new development is sharing of different spectrum assets across licensed and unlicensed boundaries, such as bonding of mobile and Wifi assets. Significant spectrum sharing of this type is expected to be a key feature
The advent of 5G mobile networks, for example, will feature the use of “bonded spectrum” approaches such as License Assisted Access (LAA) to aggregate across spectrum types, LTE Wi-Fi Aggregation (LWA) to aggregate across technologies, CBRS/License Shared Access (LSA) to share spectrum with incumbents and other deployments, says Qualcomm. In addition, there will be new platforms such as Qualcomm’s “MulteFire” that provide quality-assured services exclusively in unlicensed spectrum.
All of those developments represent a revolutionary approach to spectrum usage, moving away from command-and-control to more-dynamic allocation processes.