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15 June 2022
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Network Service Providers face challenges, but also many opportunities as they pursue advancements in DOCSIS to meet customer needs and demand for increased bandwidth, speed and lower latency.

Network Services Providers (NSPs), and more specifically cable providers, have long considered advancements in DOCSIS to be an integral part of their product roadmaps as they develop CPE (customer premises equipment) to address ever-changing customer needs for expanded bandwidth worldwide.

For cable providers, DOCSIS has been the “gold standard” with DOCSIS 3.1 (D3.1) widely available and used in CPE globally, and North America leading the charge. An example in point, Comcast has been at the forefront of this technology since 2016 [1] . In the ensuing years, D3.1 has already had 3 transitions: from modem only to gateways with Wi-Fi 5 and then Wi-Fi 6. The next step is deployment of gateways with Wi-Fi 6E and eventually Wi-Fi 7.

DOCSIS 3.1 is considered, along with other new technologies like fiber, low-band 5G, Low Earth Orbit (LEO) satellite Internet, and G.fast, to be one of the technologies that promises faster Internet regardless of where you live [2]. However, many markets worldwide have not yet transitioned to D3.1, with some having only just started to deploy D3.0 24×8. There are also some Tier 1 operators who have not yet fully transitioned to DOCSIS 3.1 either.

That being said, in the telecommunications industry there are always futuristic discussions happening around what’s next. But, in order to understand that next technological step, one must first understand the current market view. The ongoing conversation revolves around what service providers need to meet the growing demands of their customers. In essence, service providers need more spectrum, better bandwidth utilization (bits per Hz), faster service and a path to 10G.

HOW DOCSIS FIGURES INTO THE JOURNEY TO 10 G

For that journey to 10G, NSPs are discovering that DOCSIS 3.1 might not be enough as current silicon provides only 2 downstream channels, with a max of 3.6Gbps that becomes more inefficient as speeds go beyond 2Gbps. And from a cable plant perspective, NSPs need to do node splits to gain more bandwidth capacity as overall bandwidth consumption continues to grow.

This is where the next generation of DOCSIS enters the conversation. That next generation of DOCSIS, DOCSIS 4.0 (D4.0), is a powerhouse technology that focuses on extended spectrum DOCSIS (ESD) with a higher spectrum ceiling and Full-Duplex DOCSIS (FDX) which adds simultaneous transmission for upstream and downstream, both with the ability to provide even higher speeds to subscribers. CableLabs released the formal specs for DOCSIS 4.0 in March 2021 where the key pillars are higher speeds, better security and lower latency [3].

DOCSIS 4.0 is not without its challenges as it requires access network changes for NSPs. The opportunities certainly outweigh any challenges of this next gen technology, however. While DOCSIS 3.1 increased spectrum efficiency by 50%, DOCSIS 4.0 expands on the technological capability of 3.1 via the aforementioned ESD and FDX technologies.

DIVING DEEPER INTO DOCSIS 4.0: TWO FACETS

Let’s dive deeper into the two facets of DOCSIS 4.0. First, ESD, or extended spectrum DOCSIS, adds spectrum in the high range of up to 1.8 GHz, while requiring changes to both active and passive components in the cable access network, such as amplifiers and taps, to support 1.8 GHz, and ultimately providing an extra 5 Gb/s throughput to the downstream. By moving to higher spectrum in the downstream, an operator may choose to also have a higher upstream spectrum for more upstream throughput. Next, FDD or FDX, or full duplex DOCSIS, simultaneously transmits upstream and downstream in the frequency of 108-684 MHz, while requiring architectural changes in cable access plans, and necessitating so-called node+0 architecture (removal of amplifiers), resulting in the need for NSPs to move DOCSIS PHY very close to their subscribers. This technology option for DOCSIS 4.0 is even more expensive than ESD, but it does add an extra 5 Gb/s throughput to the upstream.

BENEFITS OF DOCSIS 4.0 VS. FIBER

With all of the talk about network changes required for NSPs to adopt the DOCSIS 4.0 technology and standards, another question arises: Is there a benefit to DOCSIS 4.0 vs. Fiber?

The answer to that is complicated. With the rising costs to adapt to D4.0 technology, operators are looking at digging fiber to the home as an alternative solution. The primary challenge is that the cost of laying fiber varies depending on the region/country. Operators in countries where the cost of labor is lower tend to invest in laying fiber lines rather than investing in more expensive equipment to support D4.0 across all of their networks. However, D4.0 makes more sense in environments where node+0 architecture is already in place, such as MDUs. The remote-PHY node can be connected to fiber from the street and then distributed to the apartments via existing coax cables. In this case, since there is no new network investment needed to support FDD, then this is a perfect place to upgrade to D4.0.

Supplier efforts are also starting to focus more on D4.0, as backward compatible D4.0 chips will offer a greater number of channels than current D3.1 silicon are able to provide. More channels are required to deliver >3Gb/s service speeds, so D4.0 chips may emerge as a solution to satisfy faster speeds while waiting for operators to upgrade their networks to support either ESD or FDD/FDX.

WHAT’ S NEXT ON THE ROAD TO DOCSIS 4.0?

Technicolor Connected Home, known as Vantiva, continues to gather information and data from operators to see when their networks are going to be ready for D4.0 and whether ESD or FDX makes the most sense for that operator. Technicolor is also working with silicon providers to relay this important market information to better understand what is possible and within what timeframe. As of yet, there are no definite answers as there continues to be a bit of uncertainty in the market, especially when it comes to supporting the higher cost needed to build out new access networks to support D4.0 Technicolor projects the first D4.0 products will arrive on the market at some point in 2022, but these may only be initial samples. Larger volume deployments would not be expected before 2023, and only in certain geographic areas like North America. That being said, there is already an initial push for 2Gb/s services, with a push to even higher speeds expected soon.

As the DOCSIS 4.0 technology story continues to develop, Technicolor Connected Home plans to continue leveraging RDK-B software found on all Technicolor DOCSIS 3.1 gateways thereby ensuring feature continuity and better time-to-market for operators. As the global leader in DOCSIS 3.1 deployments worldwide, Technicolor Connected Home remains at the forefront of technological advancement and growth in the telecommunications industry with commitments to providing its NSP customers globally with the necessary CPE and tools to meet the growing demands of their end- user customers.

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