Extended Spectrum DOCSIS (ESD) allows operators to extend the usable downstream spectrum on their existing HFC networks up to 1.8GHz. Requirements for ESD are being developed as a part of the DOCSIS 4.0 specifications, released by CableLabs, which promise to bring three significant improvements to the cable infrastructures, including:
- More speed
- Less latency
- Improved security
Combined with the excellent coverage of cable networks, for instance in metropolitan areas, these improvements will make DOCSIS 4.0 technologies a feasible alternative for operators on the road towards the cable industry's 10G goal. They will also lay grounds for innovations beyond consumer broadband and video services, especially within versatile smart city applications.
The big benefit of ESD is that it allows building multi-gigabit speeds, both downstream and upstream, without capex-intensive fibre investment. When combined with distributed access architecture, it enables operators to squeeze the maximun capacity out of the existing infrastructures, both coax and fibre.
What does it really take to offer 1.8 GHz services?
While ESD has been widely discussed in the cable industry, far less is known about what is required of ESD networks and what we can expect of ESD capable network elements. Yet, these issues are of importance for operators when planning their service roadmap for 2020's.
To help operators in their ESD considerations, we have identified several practical issues related to what moving towards 1.8 GHz or even beyond actually means. Our white paper, Extended Spectrum DOCSIS®: A pragmatic approach, covers these issues in more detail and provides answers to following simple, yet important questions:
- What kinds of amplifiers are needed in 1.8 GHz networks?
- What kind of performance are they expected to have?
- How can operators obtain the most out of their networks with minimal changes?
Taking a pragmatic approach to ESD:
Extended Spectrum DOCSIS®: A pragmatic approach - white paper
Extended Spectrum DOCSIS®: A pragmatic approach - PowerPoint presentation
More about the topic: How well can 1.8 GHz amplifier cascades work in 2020?
How to tackle TCP and other challenges?
A significant limitating factor for ESD implementations is total composite power (TCP) which defines how much power output an amplifier can tolerate using the technology available today. To run the 1.8 GHz services, operators need to maximize TCP available from their amplifiers, and in order to do that they need to ensure as constant network levels as possible. This can be done by introducing automatic alignment functions into the amplifiers through the Intelligent Networks technology.
Besides TCP, implementing the Intelligent Networks technology allows operators address a variety of issues related to service quality and availability and operational efficiency, such as:
- How to keep the network power consumption in control while maximizing the capacity performance?
- How to do frequency split changes from the network operating centre to avoid truck rolls?
- How to take a preventive approach towards service issues to maximize uptime and subscribers' satisfaction?
Making an ESD upgrade is a major investment and time-consuming project as it requires touching every existing element in the coax system. Accordingly, it pays off to introduce additional capabilities into networks, which could help tackle challenges in technology, service availability or operational efficiency.
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