The Future of Test Equipment and the Role of Proactive Network Maintenance

At a recent convention, I had the opportunity to listen to Daniel Howard, CTO of the SCTE, speak about how Comcast is using, Rohde & Schwarz in conjunction with their PNM (Proactive Network Maintenance) Scout Flux system.  This highlights that although PNM is the future of troubleshooting cable plant problems proactively, high-end test equipment will still be needed.  One common thread across the industry that I like to re-iterate is that the cable plant does not get better over time – it only perpetually degrades and we must always keep this in mind.  Proactively finding issues (loose connectors, loose or corroded center seizer screws, etc.) before they become problems is how Comcast (the world’s largest MSO) run’s it’s cable plant.  Hearing about how they are continually improving their metrics is really impressive.

PNM is the future of proactively maintaining a cable plant but their will still be a need for good test equipment.  PNM will displace some types of low end test equipment – this is being discussed more and more by operators and even by test equipment vendors.  Expensive and overly complicated test equipment bundles that are hard to install and need endless man-hours to maintain and only show problems after they occur (re-active not proactive) will be thought of as antiquated in the near future.  But don’t discard the need for higher end test equipment.  This is due to a lot of the basic meters (yet expensive meters) not needing to be be purchased in their current volume or at all.  There are still impairments such as impulse noise on the upstream that we are struggling to find a good solution to combat and PNM has not reached the maturity to resolve these issues.  PNM does open up the CAPEX for higher end test equipment that used to be unobtainable due to budget limitations.

In speaking with a leading provider of high-end test equipment focused on forward innovation of test & measurement, Greg Kregoski of Rohde & Schwarz had the following comments about the value proposition of troubleshooting hard-to-find impairments including impulse noise and LTE. “It’s already well understood that LTE ingress into a cable system can create havoc on a digital set-top box’s ability to demodulate and decode a video signal.  So if there is RF ingress coming from an LTE device one might expect video quality problems to occur.  This of course leads to customers satisfaction issues.  But if there is RF egress coming from a leaking cable plant there is much more at stake than just customer satisfaction problems from the wireless consumer.  Cable egress into the LTE band can be a source of reprimand from the FCC including warnings and fines.  Therefore it’s imperative for a cable operator to maintain the plant in such a way as to minimize any and all leakage.

Finding leaks in today’s cable plant is much more challenging than it used to be.  In the past the FCC’s primary enforcement of cable egress was in the VHF aeronautical band (108-139 MHz).  But with QAM channels present just about everywhere on a modern digital cable TV plant the opportunity for interference with external wireless services from egress is almost a sure thing.  Considering how much money the wireless operators have paid for this beach front UHF spectrum they will most likely exercise their right to get the FCC involved should the cable operator not react in a quick and responsible manner in remedying leaks in the 700 MHz band.”

Rohde & Schwarz offers two handheld solutions to finding leaks in today’s all-digital cable plant.  We haven’t reviewed these ourselves so we will currently leave it up to you to investigate however, from our experience Rohde & Schwarz has a history of building quality product.

The following is a great example of a LTE ingress issue.

So while this example shows an issue with the set-top box it demonstrates the identical issue that LTE will have if it ingresses onto your cable plant.  Similarly, if you have ingress you also have egress (in most cases).  So as Greg indicated in his comments, you have a high probability of the FCC knocking on your headend and potentially facing fines as your cable plant signals could very likely be invading on the Telco’s LTE wireless space.  These are very serious issues for everyone involved, including the subscriber.

Even worse, if you place your DOCSIS carriers in the 700 MHz band the LTE interference will have a very dramatic performance degradation on data.  This will be quite noticeable on VoIP.  The challenge is identifying what is causing the downstream VoIP issues as they will be intermittent.  Subscribers will complain about hearing intermittent robo-voice and even dropped called.  Downstream data traffic will slow down.  You will struggle to find the issue as it comes and goes.  So look for LTE interference or don’t put the DOCSIS channels in the 700 MHz band to avoid the problem altogether.