How Will Cable Operators Re-Architect to Add Upstream Bandwidth?

Hybrid fiber coax upgrades intended to increase upstream bandwidth can take a number of forms. Shrinking the serving areas; switching to fiber-to-home and re-architecting the network for different frequency plans are the typical choices. 

For operators who want to delay the shift to FTTH, moving from the standard HFC low-split design, and substituting a mid-split or high-split frequency plan, are the two architectural choices other than shrinking the fiber node serving areas or moving to an entirely-new FTTH network. 

As always, incrementalism is favored. Comcast appears to prefer the mid-split option, while Charter seems to be leaning towards a more-radical high-split approach. In terms of capital investment, the mid-split choice might be a shorter-window bridge to FTTH, while high-split might allow a longer window before FTTH is required. 

More symmetrical bandwidth is a large part of the thinking.  

DOCSIS 4.0 is going to force decisions about which path to take to support symmetrical multi-gigabit-per-second speeds of as much as 10Gbps downstream and up to 6 Gbps upstream.

source: Comscope 

Hybrid fiber coax networks still use frequency division, separating upstream and downstream traffic by frequency. So when a cable operator contemplates adopting mid-split or high-split designs, there are implications for active and passive network elements, especially for the more-radical high-split design. 

At this point, executives also will ask themselves whether, if radical changes are required, whether it would not be better to simply switch to fiber-to-home. 

source: Broadband Library 

Our notions of mid-split and high-split frequency plans have shifted a bit over the years, as total bandwidth has grown beyond 450 MHz up to 1.2 GHz. A designation of “mid-split”  made more sense in an era where total bandwidth was capped at about 450 MHz or 550 MHz. In those days, 108 MHz to 116 MHz of return bandwidth was perhaps 42 percent of the usable bandwidth. 

Hence the “mid-split” designation. 

Likewise for high-split designations, where as much as 186 MHz was designated for the return path, the return bandwidth represented as much as 67 percent of usable bandwidth on a 450-MHz coaxial cable system. 

source: Broadband Library  

Definitions remain, though with some new standardization of return bandwidths. “Mid-split” now features 85 MHz of return bandwidth, while “high-split” offers 204 MHz of upstream bandwidth. 

source: Broadband Library  

“Ultra-high-split” designs also are being investigated, where the upstream spectrum’s upper frequency limit can be 300 MHz, 396 MHz, 492 MHz, or 684 MHz, says Ron Hranac, consulting engineer. 

What remains true is that the ability to wring more performance out of hybrid fiber coax plant has proven more robust than many expected a decade ago. 

Also being considered are full duplex designs that swap time division for frequency division multiplexing. That is an option for DOCSIS 4.0 networks, and is a break from the frequency division HFC has used.

source: CableLabs 

Full duplex networks would allow the upstream and downstream traffic to use the same spectrum at the same time. That would require an HFC upgrade to a node-plus-zero amplifiers” design that is similar to fiber to the curb. The drop to the user location still uses coaxial cable, but without any radio frequency amplifiers. 

source: CableLabs 

The whole point of all these interventions is to supply more upstream or return bandwidth than HFC presently provides. 

source: Qorvo

Cable operators are a practical bunch, and will prefer gradualism when possible. So one might hypothesize that either mid- or high-split designs will be preferred. 

Next HFC Upgrade Will be Driven by Business Assumptions

Cable operators and mobile operators share one business commonality: capacity improvements hinge on the availability of spectrum and the degree of frequency reuse (smaller cells or serving area sizes). 

Both mobile and cable operators can effectively boost capacity by using different modulation techniques as well. But cable operators face a bigger problem, architecturally. “At some point” in the future a shift to fiber to home designs seems inevitable. 

But there are many ways to upgrade the hybrid fiber coax network before then, with varying degrees of capital investment and complexity, as well as capacity improvements. So each upgrade path embeds assumptions about what the market will require in terms of both upstream and downstream capacity , and for how long. 

DOCSIS 4.0 is going to force decisions about which path to take to support symmetrical multi-gigabit-per-second speeds of as much as 10Gbps downstream and up to 6 Gbps upstream.

source: Comscope 

Hybrid fiber coax networks still use frequency division, separating upstream and downstream traffic by frequency. So when a cable operator contemplates adopting mid-split or high-split designs, there are implications for active and passive network elements, especially for the more-radical high-split design. 

At this point, executives also will ask themselves whether, if radical changes are required, whether it would not be better to simply switch to fiber-to-home. 

source: Broadband Library 

Our notions of mid-split and high-split frequency plans have shifted a bit over the years, as total bandwidth has grown beyond 450 MHz up to 1.2 GHz. A designation of “mid-split”  made more sense in an era where total bandwidth was capped at about 450 MHz or 550 MHz. In those days, 108 MHz to 116 MHz of return bandwidth was perhaps 42 percent of the usable bandwidth. 

Hence the “mid-split” designation. 

Likewise for high-split designations, where as much as 186 MHz was designated for the return path, the return bandwidth represented as much as 67 percent of usable bandwidth on a 450-MHz coaxial cable system. 

source: Broadband Library  

Definitions remain, though with some new standardization of return bandwidths. “Mid-split” now features 85 MHz of return bandwidth, while “high-split” offers 204 MHz of upstream bandwidth. 

source: Broadband Library  

“Ultra-high-split” designs also are being investigated, where the upstream spectrum’s upper frequency limit can be 300 MHz, 396 MHz, 492 MHz, or 684 MHz, says Ron Hranac, consulting engineer. 

What remains true is that the ability to wring more performance out of hybrid fiber coax plant has proven more robust than many expected a decade ago. 

Also being considered are full duplex designs that swap time division for frequency division multiplexing. 

source: CableLabs  

Each technology upgrade path has business implications, especially the cost to upgrade HFC in some way without shifting to FTTH. The other assumption is the competitive environment and how long each alternative upgrade can support the expected business model.

Gigabit Networks Will Destabilize the ISP Market

There are times in the global communications business when stability is the main trend. The first 125 years of telecom history were such times of fundamental stability.

But there are other times when instability and change are the main trends. That might have been said to be the case when global privatization and deregulation happened in the 1980s and 1990s. And instability now is growing with the maturation of voice and the rise of Internet access and mobility as anchor services.

Some might argue growing instability is what we will see over the next decade. Consider only the impact of symmetrical gigabit Internet access service. Quantitative change is not the only issue. Qualitative competitive implications will exist for contestants using different network topologies and access media.

Consider cable operator frequency plans and use of hybrid fiber coax, for example. Executives typically argue that HFC can be upgraded incrementally to support future bandwidths of that sort.

To support gigabit networks, it is argued, fiber is simply extended deeper in the access network, decreasing serving area size by about an order of magnitude, creating the same sorts of advantages mobile operators gain by using a fixed amount of spectrum in a cellular configuration.

Though the least disruptive, such an upgrade might feature per-user peak bandwidth of 100 Mbps, still an order of magnitude slower than Google Fiber’s 1 Gbps, symmetrical. Some say only the high-split and new top-split frequency plans, all featuring more fiber, will support gigabit speeds.

But some might suggest it would be easier to overlay some sort of fiber to home capability than to dramatically change frequency plans now commonly used by U.S. cable operators to support symmetrical gigabit Internet access services. At least so far, most cable executives deem that too expensive an approach.

Though three different frequency plans (low split, mid-split, high split) have been available for decades, virtually all cable operators use the low split plan. Basically, that means frequencies up to 54 MHz are reserved for return signals, while all the rest of the bandwidth up to about 850 MHz is used to support downstream communications and services.

But even traditional “mid-split or high-split networks are not symmetrical. The mid-split frequency plan increases return bandwidth up to about 85 MegaHertz. The high-split network increases return bandwidth to about 200 MHz. The new top-split network offers support for gigabit speeds gigabit speeds.

For cable operators, as for others using radio frequency networks,  the challenge symmetrical gigabit services pose is not simply quantitative (more) but qualitative (equal split networks are needed).

Big Strategic Shift for FTTH?

The strategic context for U.S. home broadband is evolving. For two decades, cable TV operators have been able to consistently maintain installed base share close to 70 percent, in most years getting the majority to all of the net new account additions. 

That remains the case in 2021, as cable continues to hold its installed base lead and also continues to win the net new additions battle.  

All that now seems set for change, though. The biggest change is an up- tempo pace of fiber to home conversions by telcos. But new 5G high-bandwidth fixed wireless offerings should claim some share as well. 

source: New Street Research 

Also important is the way some telcos are positioning their upgrades. In the past, they might have been content to match cable offers. Now some are aiming to surpass cable offers, with symmetrical upstream bandwidth a weapon.  

Frontier Communications, for example, is preparing rollout of a 2-Gbps offer, in addition to its standard 1-Gbps and entry-level 500-Mbps offers. That will likely feature symmetrical bandwidth. 

To be sure, cable is working on its own 10-Gbps capabilities, as well as methods to add more upstream bandwidth. But many of those solutions are not graceful upgrades from the existing hybrid fiber coax platform. The choice is whether to revamp HFC in significant ways or switch to FTTH as the replacement. 

More upstream bandwidth could be provided, to some extent, by pushing fiber deeper into the HFC network. Alternatively, cable operators can swap frequency plans, moving to mid-split or high-split designs. But all those moves require disruption of the physical plant, and cannot be accomplished by swapping out end user gear, as has been the case in the past. 

And any shift to fiber deeper networks, mid-split or high-split architectures (or two of the above) essentially delays an eventual shift to FTTH in any case, many would argue. So the decision comes down to “spend less now, but more in the long term, while undertaking a major network disruption twice” or “spend more now, and be done with it, and only disrupt operations once.” 

The larger point is that upgrading to FTTH comes with other choices that can confer advantage. Bandwidth can be symmetrical, or not. Bandwidth can top out at various levels: higher or relatively lower. And retail pricing, terms and conditions also make a difference. 

Much thinking now seems to be going into how to tweak those parameters to gain advantage over cable operator competitors. Many might assume FTTH means gigabit speeds. It does not. FTTH is physical media. Service providers still must decide how much bandwidth they want those networks to supply. 

Historically, FTTH might have meant speeds in the hundreds of megabits. Some U.S. FTTH networks installed in the mid-1990s to late 1990s offered speeds only up to 10 Mbps. User experience might be an order of magnitude less than advertised, however, even on FTTH platforms.  

What seems to be changing is a willingness to leverage FTTH to gain a speed advantage. 

 

“Our network is already 10-gig capable end-to-end, so we can carry on driving up speed tiers, as demand requires, in a very low-cost, very quick way, again, in a way that cable can't, says Nick Jeffery, Frontier Communications CEO. 

But that only matters if most Frontier customers can buy the service. 

“Our plan (is) to reach a total of five million fiber locations by the end of 2022 and 10 million locations by the end of 2025,” says Nick Jeffery, Frontier Communications CEO. 

Frontier has 15.2 million locations passed, so 10 million total FTTH passings means about 66 percent of the potential customer base would be able to buy FTTH services. 

Of course, a higher installed base does take time. “Our 2020 expansion cohort continues to show strong penetration of 30 percent at the 12-month mark,” says Jeffery, though noting that figure is based on a small sample. 

“For the overall build plan, we continue to expect a 15 percent to 20 percent penetration rate at the 12-month mark, and with penetration continuing to rise in subsequent years toward a terminal penetration of 45 percent,” he added. 

Government subsidies also are expected to improve the business case for FTTH and other high-speed services, as they are increasing substantially. 

George Ford, economist at the Phoenix Center for Advanced Legal and Economic Public Policy Studies, argues that about 9.1 million U.S. locations are “unserved” by any fixed network provider. 

Though specifics remain unclear, it is possible that a wide range of locations might see their deployment costs sliced by $2,000 or more. Lower subsidies would enable many more locations to be upgraded to FTTH, for example: not the unserved locations but possibly also many millions of locations that have been deemed “not feasible” for FTTH.

Much hinges on the actual rules that are adopted for disbursement. Simple political logic might dictate that aid for as many locations as possible is desirable, though many will argue for targeting the assistance to “unserved” locations. 

But there also will be logic for increasing FTTH services as widely as possible, which will entail smaller amounts of subsidy but across many millions of connections. The issue is whether to enable 50 million more FTTH locations or nine million to 15 million of the most-rural locations. 

Astute politicians will instinctively prefer subsidies that add 65 million locations (support for the most-rural locations plus many other locations in cities and towns where FTTH has not proven obviously suitable). 

The issue is the level of subsidy in various areas. 

“According to my calculations, if the average subsidy is $2,000 (which is the average of the RDOF auction), then the additional subsidy required to reach unserved households is $18.2 billio,” Ford argues. “If the average subsidy level is $3,000, then $22.8 billion is needed. And at a very high average subsidy of $5,000, getting broadband to every location requires approximately $45.5 billion.”

The point is that, compared to the business case 20 years ago, FTTH is better in a number of ways. Strategically, copper facilities simply are outmoded. Any fixed network operator clinging to that platform is destined for death. 

Financially, the older triple-play model--with its cost structure and complexity--now is out of favor. The new model is based on home broadband: the sole service for an independent ISP, and the growth driver for an incumbent telco. 

Oddly enough, the older justification for FTTH--that it allows telcos to support many services--now is eclipsed by the simple value of internet access. The value of the “do anything” platform still remains. 

Only these days the primary value driver for an incumbent telco or independent ISP is “access.” Voice or video entertainment might contribute additional revenue and value, but where there is a choice, new providers simply build on home broadband, leaving apps to be supplied by others. 

All that is a big potential change.

U.S. Cable Operators Will Lose Home Broadband Share, But How Much, and to Whom?

Comcast says it will lose about 100,000 home broadband accounts in the fourth quarter of 2024, a troublesome statistic given that service’s past-decade role in fueling company revenue growth. 

By most estimates, the U.S. cable operators will lose market share to other contestants to 2030. The issue is “to whom” the losses will occur. By volume, the shift to telcos is likely to be the biggest. Satellite access might gain, but the magnitude remains unclear. Share held by third-party independents might not change. 

ISP Segment	2025 Market  Share	2030 Market Share	Key Drivers
Cable TV Providers	58%	45%	Increasing competition from 5G fixed wireless Legacy infrastructure becoming less competitive Price pressure from new entrants
Telcos (Combined)	30%	38%	5G fixed wireless growth in suburban areas Fiber deployment acceleration Mobile/fixed service bundling
Satellite	7%	12%	LEO constellation maturity (Starlink, Project Kuiper) Improved latency and speeds Rural market penetration
Independent ISPs	5%	5%	Municipal networks growth Local fiber deployments Consolidation pressure from larger players

The issue is growing competition for new fixed wireless services on one end of the demand spectrum, plus fiber-to-home services on the other end. Put simply, fixed wireless seems to be taking market share from cable services among customers content to buy services offering 100 Mbps to 200 Mbps of downstream bandwidth, while FTTH is taking share among customers who want 1 Gbps or faster, and sometimes more upstream bandwidth. 

In my own case, I can get around 1 Gbps from both my hybrid fiber coax provider and a FTTH provider. That isn’t the issue. The HFC upstream runs at about 17 Mbps. The FTTH connection is reliably operating at 940 Mbps. 

And the point is not that I “need” 940 Mbps upstream. I don’t. The point is that upstream performance is 55 times greater for the FTTH provider than the HFC provider, at zero cost premium. 

For that matter, I don’t “need” 1 Gbps in the downstream direction, either. The point is that I wouldn’t consider buying any service operating at speeds less than 1 Gbps. It is not a matter of “need” but of preference or “want.”

Somewhat ironically, U.S. cable TV operators face almost the same issues as do telcos when pondering upgrades of their legacy networks. Traditionally, telcos have had to fund a complete replacement of their copper access networks with fiber-to-home platforms to support broadband services. 

And telcos have generally tried to be rational about the capital expenditures, generally deploying FTTH in greenfield areas (new home construction, for example). But that might only represent about one percent to two percent of housing locations per year. At that rate, it will take quite some time to complete a full transition to FTTH. 

Cable operators face the same dilemma. 

Telcos also have justified FTTH upgrades in neighborhoods where demand is greater and willingness to pay is higher. Cable operators might make the same decisions. 

And much hinges on changes in customer demand for symmetrical bandwidth and faster speeds, as there is a point where HFC cannot compete with FTTH (perhaps at about 10 Gbps). That might give cable operators about a decade of running room before a network replacement is required. 

That might assume that “typical” U.S. home broadband speeds reach 1 Gbps by perhaps 2026, with upgrades beyond that to 3 Gbps to 10 Gbps over a decade. 

But that also assumes the key issue is downstream bandwidth, not “symmetrical” or “more nearly symmetrical” bandwidth. Though most observers arguably do not believe upstream bandwidth symmetry is a huge issue for the near future, its importance seems likely to grow. The issue is whether demand for symmetry grows slowly or faster. 

Market demand for products sometimes is not based on “need” but “want,” and some users might already make buying decisions as though symmetrical bandwidth is preferable, even if no application currently requires it, and even if multi-user demands do not require it. 

source: ITIF 

So bandwidth demand beyond the capabilities of the HFC network will force a platform upgrade that telcos already have been facing with the upgrade to FTTH from copper access, even if HFC has a more-evolutionary path remaining, before a full platform shift is necessary. 

Cable operators have been able to gradually and incrementally upgrade their once-copper networks to hybrid networks featuring fiber backbones and retaining copper distribution. But a disruption is coming. No matter how far cable operators extend fiber closer to end user locations, increasingly more-difficult adaptations are necessary. 

Traditionally, the simple remedy was to replace coaxial cable in the backbone with fiber, which was fairly simple, as the rest of the network remained untouched. But moving in the direction of more-symmetrical bandwidth is tougher, requiring revamping all active elements of the copper network. 

High-split hybrid fiber coax networks allocate up to 204 MHz for upstream traffic, compared to only 42 MHz (USA) or 65 MHz (Europe) in sub-split networks. That represents as much as five times more upstream capacity compared to 42-MHz sub-split upstreams.

But even a high-split network will not be able to support symmetrical bandwidth, as FTTH systems now do. So long as customers do not demand symmetrical bandwidth, perhaps that is not an existential issue. 

But if the market shifts to a preference for symmetrical bandwidth, cable operators will, at some point, have to invest quite a bit more than they presently do in network capital investment, as they will essentially have to replace HFC with FTTH access networks. 

There also is a new wrinkle, namely that some demand for lower-bandwidth connections apparently has grown for fixed wireless alternatives. 

We can see that demand shift in statistics on home broadband net gains and losses. 

Company	Q1 2024 Net Broadband Subscribers	Q2 2024 Net Broadband Subscribers	Total Net Additions (Losses) Q1, Q2
Charter	(81,000) losses	(72,000) losses	(153,000) losses
Comcast	(38,000) losses	(34,000) losses	(72,000) losses
AT&T	Slight gains	Slight gains	Approximately 50,000 gains
Verizon	Minor losses	Minor losses	Approximately (50,000) losses
T-Mobile	226,000 gains	246,000 gains	Approximately 472,000 gains

Company	Net Change (Q3 2024)
Charter	-113,000
Comcast	-87,000
AT&T	+50,000
Verizon	+28,000 (Fios) plus 363,000 fixed wireless
T-Mobile	+415,000 fixed wireless