By John Ulm, Dr. Martin Zimmerman, PhD, Stuart Eastman & Zoran Maricevic, PhD, CommScope
Cable 10G and Wireless 5G may seem to be at odds. However, when combined, they offer an evolutionary strategy with much synergy.
5G uses a collection of different frequency bands, each with unique characteristics. Recent developments in C-band, CBRS (Citizens Broadband Radio Service) and Wi-Fi provides some new mid-band spectrum (i.e. 3 - 6 GHz) that is offering a middle ground that may be the future wireless workhorse. Its reach covers a significant number of mobile users with substantial data rates. But its deployments may need many more densely packed cell sites than current 4G LTE macro-cells. This presents an opportunity for MSOs to leverage their existing HFC infrastructure for providing both backhaul and power to those new cell sites.
The paper presents a basic tutorial on mid-band wireless technologies in the 3-6 GHz range that includes C-band, CBRS and Wi-Fi 6E. It covers MIMO antenna systems from 2T2R to 64T64R and when and where each is appropriate. ORAN (Open Radio Access Network) standards help to virtualize the 5Ginfrastructure, identifying backhaul, midhaul and fronthaul interface options.
The many choices for the mid-band wireless system can vary bandwidth requirements from 100’s Mbpsto many 10’s Gbps. The paper shows which configurations can easily be supported on DOCSIS 3.1 while others might require DOCSIS 4.0 and some may need direct fiber connect.
Some case studies are provided where potential mid-band small cells are mapped to actual HFC networks.
Results from a CBRS design show its potential reach. This data is used to map cells to several existing HFC nodes. The nodes under study vary from dense urban nodes (i.e. >250 HP/mile) down to sparse rural nodes (i.e. <40 HP/mile). Various trade-offs are considered in cell site placement on the HFC.
HFC appears to be ideally suited to support this Mid-band xHaul infrastructure. A strategy is laid out for cable plants of varying densities. D3.1 midhaul can be leveraged extensively in the early days to get wide coverage quickly. Very dense urban areas will eventually require complex antenna/MIMO systems with fiber fronthaul. This integrates nicely with an N+2 fiber deep strategy. But even then, cells with DOCSIS xHaul will be needed to fill the holes and hotspots. D4.0 then enables even higher capacities at these cable cell sites.
In the end, Cable and Mid-band wireless (C-Band, CBRS, Wi-Fi 6E) are much stronger together and area the core of a next gen converged network evolution.