{"id":917,"date":"2019-06-13T13:03:11","date_gmt":"2019-06-13T11:03:11","guid":{"rendered":"https:\/\/excentiscom.webhosting.be\/?p=917"},"modified":"2022-06-24T08:08:53","modified_gmt":"2022-06-24T06:08:53","slug":"is-docsis-3-1-truly-great-or-is-it-driven-by-hype","status":"publish","type":"post","link":"https:\/\/www.excentis.com\/blog\/is-docsis-3-1-truly-great-or-is-it-driven-by-hype\/","title":{"rendered":"Is DOCSIS 3.1 truly great, or is it driven by hype?"},"content":{"rendered":"

When I hear people talking about DOCSIS 3.1 and its great performance, the critic in me wonders:\u00a0is the technology as good as promised, or is it all just savvy marketing?<\/em>\u00a0In this blog post, we\u2019ll be taking a look at the promises and the challenges of DOCSIS 3.1.<\/p>\n

Download speeds of 10 Gbps and upstream speeds of 1 Gbps: that\u2019s what the DOCSIS 3.1 standard from CableLabs promises. But is this goal achievable in a real-life network environment? We\u2019ll walk you through the considerations.<\/p>\n

3 ways DOCSIS 3.1 enables higher speeds<\/h2>\n
    \n
  1. Flexible modulation<\/strong>
    \nWhen launching DOCSIS 3.1, CableLabs introduced a completely new physical layer scheme: orthogonal frequency-division multiplexing (OFDM(A)<\/a>), which allows for flexible QAM modulation (called profiles). Both low and very high-order modulations (from QPSK to 16K QAM) can be used depending on the available signal quality (SNR) in that area of the channel (spectrum) and at that time (meaning for\/from a specific modem or set of modems)<\/li>\n
  2. Superb error correction<\/strong>
    \nEven more, DOCSIS 3.1 benefits significantly from the introduction of the world-record-holding error-correcting algorithm,\u00a0the low-density parity check<\/strong>\u00a0(LDPC). This superb coding\/decoding mechanism enables the use of higher modulation orders under current plant signal quality conditions, resulting in higher speed\/capacity.<\/li>\n
  3. Double the spectrum<\/strong>
    \nOn top of that, DOCSIS 3.1 allows a\u00a0wider frequency spectrum<\/strong>, optionally up to 1.8 GHz. Doubling the spectrum really means doubling the capacity!<\/li>\n<\/ol>\n

    Do I have to upgrade my network for DOCSIS 3.1?<\/h2>\n

    The key approach of DOCSIS 3.1 means that a network upgrade is not a necessity: it can be deployed in the current network and still lead to capacity increases.<\/p>\n

    Illustrating these benefits, a DOCSIS 3.1 deployment in a real operator network from mid-2019 resulted in a gain of nearly 50% capacity potential without extra network investments. The graph below shows how often which modulation was in use: 100% QAM256 for D3.0 and nearly 96% QAM4096 for D3.1.
    \nThat means that using the same spectrum for OFDM instead of SC-QAM results in a capacity gain of almost 50%. If a 192 MHz OFDM channel can be added on top of the existing 24 SC-QAMs, the potential capacity even increases by a factor of 2.5! Of course, the real gain depends also on how many D3.1 modems are deployed.<\/p>\n

    Using the same spectrum with OFDM results in a capacity gain of almost 50%<\/p><\/blockquote>\n

    Before you start: questions and challenges to keep in mind<\/h2>\n

    Most of the advanced new DOCSIS concepts described above entail some challenges and key questions to ask before moving forward with your DOCSIS 3.1 deployment. Make sure to ask yourself the following questions:<\/p>\n