The key impetus behind cable technology evolution is finding ways to make data transmissions over HFC more efficient and effective - thus enabling growth in cable broadband and the ability to provide wireline backhaul for mobile.
The Data Over Cable Service Interface Specification (DOCSIS) is the foundation for all of this. The latest iteration, DOCSIS 3.1, has been developed to enable high-bandwidth data transfer speeds of up to 10Gbps downstream and at least 1Gbps upstream, bringing cable HFC into line with the very best ‘full fibre’ wireline capabilities. Cable is also preparing to offer Full Duplex DOCSIS, an emerging spec that will enable identical upload and download speeds of 10Gbps, and is now drafting a broader proposed spec, DOCSIS 4.0. Both Full Duplex and DOCSIS 4.0 are actually part of a larger suite of complementary technologies known as 10G which are designed to help deliver ultra-low latency, ultra-high reliability and much more.
Taken together, the DOCSIS 3.1, Full Duplex, the proposed DOCSIS 4.0 spec and other related 10G innovations are intended to pave the way for the next generation of high-bandwidth advanced applications, including ultra HD/4K video, 8K video, immersive Augmented Reality (AR) and Virtual Reality (VR) experiences, driverless vehicles, and real-time collaborative gaming, plus the massive explosion in networked devices expected as the ‘smart’ IoT revolution takes hold in our homes, in our cities and industry. And that’s just the tip of the iceberg.
In terms of rollout, Swiss cableco Sasag in April became one of the first European operators to upgrade its entire network to DOCSIS 3.1, enabling upload speeds of 100Mbps and downloads of 1Gbps. Vodafone Germany is reported to be working on a complete Full Duplex upgrade to deliver 1Gbps symmetrical speeds to its 12 million cable customers. Other European cablecos moving forward with DOCSIS 3.1 upgrades include Liberty Global in the UK and Germany, Vodafone Spain, com hem AB in Sweden, TDC Group and Stofa in Denmark and, most recently, Eltrona in Luxembourg.
Many of these companies are also utilising deep-fibre strategies to further improve performance in data transmissions - extending the fibre component of an HFC network further and further towards the end user, maximising the extra speed and efficiency of optical signals before they are translated back into an electrical signal and carried on a coaxial wire. One of these approaches, a distributed access architecture (DAA) methodology known as Remote PHY, has been trialled by com hem AB in Stockholm. It involves moving part of the cable modem termination system (CMTS) from the headend to the network edge to be as close as possible to the customer’s equipment, thus delivering higher bandwidth and through put.