By Nader Foroughi, Shaw Communications
DOCSIS® 4.0 technology was created as a part of the 10G roadmap to increase capacity in both upstream (US) and downstream (DS). As we prepare to deploy this technology, the attention is rapidly shifting towards upstream, which was accelerated due to COVID-19. Last year, a noticeable jump in upstream utilization was realized by almost all multiple service operators (MSOs) worldwide, emphasizing the need for higher throughputs in the upstream. The shift to working remotely, learning from home, videoconferencing and increased gaming activity demonstrated the need to increase bandwidth in the upstream to meet evolving consumer appetites.
Currently, many multiple system operators (MSOs) operate in 42, 65 or 85 MHz plant. The smaller bandwidth benefits the modems and amplifiers operating in the return spectrum. The same operators are planning on expanding the upstream spectrum bandwidth to 396 or 492 MHz in the near future, with 204MHz as an intermediate step. Many operators are also planning on deploying DOCSIS 4.0 capable equipment in existing plant without re-spacing, which means there are a few key challenges to be considered.
In this paper, we will evaluate the DOCSIS 4.0 plant models by addressing these key challenges, including modem transmit capabilities, upstream amplifier performances and potential upstream performance expectations for various node and serving group architectures. The goal is to highlight the main areas that should be prioritized to ensure optimal DOCSIS 4.0 upstream performance in the access network.
Furthermore, this paper primarily aims to shed light on areas of the US that we need to focus on, along with providing new insights into performance of nodes and serving groups based on their characteristics and properties. The DOCSIS specifications define what can be expected from the cable modem (CM) and the cable modem termination system (CMTS). However, it does not specify what performance MSOs can expect in various plant architectures. This paper outlines the most important areas of focus for the optimal approach to deploying DOCSIS 4.0 technology in the US and sets expectations for performance in the access network.