CBRS Alliance to work on 5G compatibility
Around the world, the 3.5 GHz band has been tapped by operators as key mid-range 5G spectrum. In the U.S. that frequency, referred to as the Citizens Broadband Radio Service band, is set aside for LTE services. A spectrum access system, based on a three-tiered licensure system, will protect incumbents while opening up the band for operators to augment capacity and for enterprises and industries to stand up private networks.
And while the focus has been on deploying LTE in the CBRS band, the cross-industry CBRS Alliance says it will work out technical specifications to make shared access to 3.5 GHz compatible with 3GPP’s 5G New Radio air interface. There’s a lot of benefits that will come with this move, chief among them simplified device development and commercialization based on global alignment around 5G in 3.5 GHz.
“Utilizing the CBRS band can be a key enabler for making 5G deployments possible. The Alliance is hard at work developing technical specifications to ensure that OnGo supports 5G applications as seamlessly as traditional LTE services,” Gary Boudreau, chair of the CBRS Alliance’s Technical Working Group, said in a statement. “The specifications in development include addressing coexistence requirements to ensure seamless interoperability between LTE and 5G NR in and out of Band 48, certificate-based authentication, and more.”
Moving from shared access to standalone deployment of 5G in unlicensed spectrum, 3GPP has an active study item that considers using the 5 GHz and 6 GHz bands to support 5G NR, referred to as NR-U. The idea of standalone cellular in unlicensed spectrum started with MulteFire.
The group driving that is the MulteFire Alliance, which focused its 1.1 specification on using the configuration for internet of things implementations. In terms of commercialization, the group baked-in support for the 1.9 GHz band, referred to in Japan as sXGP, and has developed an ecosystem of users in that market, including widespread device and eNodeB compatibility.
“MulteFire technology operating standalone in the 1.9 GHz band brings new capabilities to our enterprise subscribers, and it will help enable us to connect billions of new IoT devices,” Yoshioki Chika, MulteFire Alliance Board Member and Senior Director of SoftBank’s Solution Strategy Office, said in a statement.
There are two primary modes of operation for NR-U–carrier aggregation and standalone, according to Qualcomm VP of Technical Standards Lorenzo Casaccia.
The first, Casaccia said, is analogous to LAA for LTE. “You have an anchor in licensed spectrum, then you add an additional carrier in unlicensed spectrum. Conceptually it is the same thing as we’ve done in LTE.” He said standalone NR-U can be thought of as the 5G NR answer to MulteFire for LTE.
“We are defining 5G that can be operated in unlicensed spectrum alone without restrictions and without any anchor in licensed spectrum. It’s really the first time that 3GPP defines a technology that can be run in just unlicensed spectrum. It’s really a major, major milestone for 3GPP…As a technology it’s a major milestone for the cellular industry to really make the jump and make cellular technology that just goes into the unlicensed spectrum. From a business point of view, it opens up possibilities for local deployment, private networks, many other use cases.”
