By Maxwell Huang, Cisco Systems
The DOCSIS 3.1 PHY and MAC standards have specified the QAM modulation order as high as to 16384QAM, however, we could not go beyond 512QAM (or 1024QAM) order on the current HFC plant as the CNR performance is primarily limited by analog optics and long amplifiers cascade. Hence, to achieve the 10G cable access goal we will have to expand the cable spectrum to a very high frequency like 1794MHz. But the 1794MHz expansion in cable spectrum appears too challenging and leaves tremendous concerns…
The paper aims to explain the ideas of evolving the HFC plant to have the better CNR performance and hereby be able to support the high QAM modulation like 4096 QAM, so that we may just need to expand the cable spectrum to a relatively lower frequency like 1.44GHz to make HFC a 10G access network.