Issue link: https://iconnect007.uberflip.com/i/1528798
64 SMT007 MAGAZINE I NOVEMBER 2024 and wireless access via Wi-Fi. Wired access is secure and capable of high data speeds but suffers from lack of mobility and high cost of implementation. Wi-Fi, on the other hand, is relatively easy to implement and is good for office environments but has many other limitations that make it unsuitable for use in manufacturing environments, as discussed later in this paper. ere is a need for a solution that combines the best of wired and wireless worlds. As further elaborated in this article, private wireless networks based on standards-based and well-proven 4G/LTE (long term evolution) and 5G cellular tech- nologies are the answer and key enablers for Industry 4.0. Private Cellular Networks Cellular networks require electromagnetic/ wireless spectrum. Wireless spectrum was his- torically auctioned by the FCC on a nationwide basis and required billions of dollars to pur- chase nationwide licenses. Only large nation- wide wireless network operators or large util- ities could afford to acquire the spectrum and offer nationwide cellular services. To drive nationwide adoption of broad- band and 5G technologies, two years ago the FCC changed its spectrum regulatory strat- egy and released 150 MHz of CBRS (Citizens Broadband Radio Service, Band 48) spectrum from 3.55 GHz to 3.70 GHz for shared com- mercial and federal use under dynamic spec- trum sharing rules. As shown in Figure 1, the FCC created three tiers of users for the spec- trum. Tier I users are the incumbent federal users—mostly fixed satellite stations and naval ships who use the spectrum on a limited basis for sea-to-shore communication. rough a spectrum auction in 2020, the FCC further offered seven 10 MHz channel licenses on a county-by-county basis creating a set of Tier II Priority Access License (PAL) users— with no single PAL licensee getting more than three channel licenses per county. A total of 22,631 licenses were awarded across 3,233 U.S. counties. e remaining 80 MHz of spectrum was le unlicensed for Tier III General Authorized Access (GAA) users. Per dynamic spectrum sharing rules, Tier I users have highest priority for spectrum access fol- lowed by Tier II users who are followed by Tier III users. e availability of unlicensed and lightly licensed CBRS spectrum on a county-by- county basis removed spectrum as an entry barrier and made it possible for large and small enterprises to own private cellular networks. Another technology evolution enabling private networks was the transition of the very expen- sive core cellular network (Evolved Packet Core or EPC) to the cloud. Cloud hosting of the EPC allowed large numbers of customers to securely share the core network, making private cellular networks further affordable to enterprises both large and small. Figure 1: Three user tiers for CBRS spectrum.