By Rob Thompson, David Urban, Rob Howald of Comcast Cable, Satheesh Angaiah, David Geeter of Electro Rent Corporation, and Murthy Upmaka of Agilent
CableLabs has opened a new chapter in CATV digital communications with its latest installment of DOCSIS® 3.1. New DOCSIS® 3.1 capable products are expected to start showing up in 2015 time frame. Meanwhile, cable operators are looking into ways to start kicking the tires of OFDM-based PHY now by employing readily available simulation tools to produce DOCSIS® 3.1 PHY signals and subject them to a variety of simulated channel conditions. Cable operators may also be aware of how some of these powerful simulation tools can be combined with signal generation and analysis equipment to produce DOCSIS® 3.1 signals that may be used to get an early look at how CATV systems will react to the new DOCSIS® 3.1 PHY. Simulation systems may be created to allow for deeper-dive into supported parameter sets, driving toward identification of optimal modulation profile settings, such as choosing appropriate cyclic prefix (CP) for expected channel conditions, or evaluating windowing parameter impacts to adjacent SC-QAM performance. The authors wish to provide an initial reference point associated with porting DOCSIS® 3.1 PHY simulations into RF signal stimuli for more detailed analysis of how this new PHY performs across laboratory-based CATV systems. The authors expect to include both test topologies and new data resulting from these enhanced simulation capabilities, enabling others to contribute and add to this exciting new chapter in CATV digital communications.