“In a perfect world, IPTV works flawlessly in every deployment, and subscribers are completely satisfied.”

You may agree that this statement is a bit strong, if not futuristic, in its messaging; however, much can be done today in pursuit of perfection of IPTV deployment over existing copper infrastructure. IPTV, as well as technologies that transport IPTV, have advanced greatly over the past several years -- standards, equipment, and telco methods and procedures are allowing service providers to remain competitive against MSO/CATV/satellite providers. Successful IPTV deployments can be seen all over the world, but this success was made possible only after learning that reactive testing was the expensive approach whilst proactive testing -- before or during the IPTV installation process -- saved valuable OpEx.

Today’s Deployment Challenges
Service providers’ existing copper loop plant can be classified as unique, in that each copper deployment is unique in one way or another. While the copper loop follows roads, streets, conduits and aerial lines, it is made up of different wire gauges, with splices at different points, and transverses different regions, which allow different types of narrowband and wideband noise to be picked up.

There’s also a myriad of faults that can exist on the copper plant, and a service provider needs to be prepared to quickly and accurately determine the type and location of a fault that could prevent a successful deployment of IPTV to paying subscribers.

The old adage is that “time is money”, but in today’s environment, it seems that people have neither the time nor the money. Basically, without subscribers, there’s no money -- so we have to make time.

One way that we found to do this is by doing things “first time right”. By utilizing a single test set that offers the technician the ability to analyze each layer (copper, DSL/Ethernet/HPNA and IPTV) and by way of the use of auto-tests (a sequence of measurements assembled together in one convenient place that allows a technician to get a clear picture of the circuit quality at the push of a button), the technician gets a complete picture of not only the copper plant quality but the quality of the higher layers too -- all the way to the main tool, delivering IPTV “first time right”.

IPTV quality of service (QoS) and quality of experience (QoE) are mandatory, since these are the first service offerings that subscribers use to truly compare against existing services offered by cable television (CATV) and satellite companies. Any impairment on the network can affect the customer experience and the quality of the IPTV stream. When user datagram protocol (UDP) is used, there is no retransmission of the lost packets and, as a result, the quality of the IPTV is affected to various degrees since the packet loss contributes to gaps in the IPTV stream.

Therefore, the signal quality across the IPTV network must be monitored to minimize customer complaints of poor service. Consequently, effective and thorough testing to identify and remove impairments on the network is an absolute necessity for successful IPTV service deployment.

Once proper testing methods and procedures are put in place, the benefits are substantial, including:
• Verify that the copper plant can properly handle the demands of high-bandwidth IPTV services.
• Simplify the subscriber IPTV turn-up and installation verification process.
• Identify, isolate, and resolve problems before customers are impacted and costly repeat truck rolls are required.
• Exceed subscriber QoE and QoS expectations.

Best Test Practices to Ensure Reliable High-Quality Roll Out of IPTV
The tool that a technician needs must enable to analyze most, if not all, situations that may arise. Although the technician may not have the authority to fix a fault, being able to identify and document why the customer’s service is not working goes a long way to improving efficiency of the service provider.

It should be noted here that only the term “copper plant” or “copper infrastructure” has been mentioned thus far -- validation of outside plant “copper” pair quality is equally important to ensure that the inside plant (in-home) “copper” Ethernet and coaxial deployments (i.e., HPNA) do not impede the delivery of IPTV, as well as other high-bandwidth applications (such as high-speed Internet).

Outside Plant Quality Makes It All Work
With VDSL2 and IPTV deployments, wideband testing is essential. Even for providers offering IPTV over ADSL2+, testing above and beyond the voice frequency spectrum is needed. As DSL is delivered over the outside copper plant, the best practices are to ensure that the copper is free of impairments at multiple locations (i.e., remote and demarcation point). There are a number of points that a technician must evaluate when conducting copper and DSL testing for proper deployment of IPTV. Many tests can be performed by use of an auto-test, which indicate to the technician whether or not the IPTV deployment will be successful.

Six of the more important proactive tests include:
1. Time and frequency domain reflectometry (typical TDR/FDR traces and wiring diagram versions)
Is the copper pair too long? Are there any faults? Where is the location of DSL bandwidth robbing bridged taps?

2. 30 MHz spectrum analysis
Is there too much crosstalk that will impact DSL performance out to 30 MHz?

3. 30 MHz longitudinal balance
Is the circuit properly balanced out to 30 MHz?

4. Impulse noise histogram
When and how often could the subscriber’s service be impacted by impulse noise? Do I need to activate impulse noise protection?

5. DSL sync
Is the actual data rate acceptable? Is there enough margin? Does the circuit see the CRC and FEC issues?

6. Join/leave IPTV streams
Is the IPTV service available? Does the circuit have enough bandwidth to handle multiple HD and SD streams? Packet loss? Jitter?

Inside Plant Challenges
It has been suggested that the majority of issues related to the roll out of services can be found inside the subscriber’s location. Several service providers have already taken steps to ensure that when a subscriber orders IPTV, it is not delivered only to the demarcation/network interface device, but it is delivered all the way to the subscriber’s television set. This goes a long way towards the “first time right” philosophy and significantly helps reduce the need for repeat truck rolls.

If the inside plant is ignored and left up to their own devices, subscribers will likely complain, loudly, stating that their IPTV service is poor. A service provider, competing alongside the CATV and satellite offerings, cannot afford negative publicity.

By taking ownership in the home, service providers can quickly determine if the existing coaxial infrastructure is suitable for use or if new Ethernet cabling needs to be installed. The typical scenario is to reuse the existing coaxial cable by adopting HPNA for delivering high-quality IPTV throughout the subscriber’s residence.

Some of the more important proactive tests for inside the subscribers’ residence include:
DSL sync
Is the actual data rate acceptable? Is there enough SNR margin? Is the circuit seeing CRC and FEC issues?

HPNA analysis
Can we see all the HPNA devices in the home?
Is the data rate high enough? Is there enough SNR margin? Is the noise acceptable?

Join/leave IPTV streams over DSL, Ethernet, and HPNA   
Is the IPTV service available? Does the circuit have enough bandwidth to handle multiple HD and SD streams?

Potential for Perfection
Service providers are faced with mounting pressure to deliver IPTV service in order to regain their revenue streams in addition to going against the competition in the voice, data, and video market. In order to deliver reliable IPTV service, it is extremely important to invest in proactive testing. Furthermore, implementing cable-plant conditioning techniques for IPTV services can eliminate a substantial number of potential subscriber complaints and, consequently, reduce the amount of unnecessary truck rolls.

Consideration should also be given to network equipment that incorporates new technologies enabling end-to-end adaptation of the ever-changing environment, which helps eliminate the remaining impairments that may be present in a well-conditioned copper plant.

In closing, as technologies improve and deployment practices become more streamlined, proactive testing will remain the best way to ensure reliable IPTV deployment over copper infrastructure.

Chris Dunford is a Product Line Manager for EXFO’s Wireline Access Business Unit. He has responsibility for handheld products focusing on physical layer FTTN and advanced Triple Play services testing. For more information about EXFO, visit www.exfo.com.

EXFO is a provider of next-generation test and service assurance solutions for wireless and wireline network operators and equipment manufacturers in the global telecommunications industry. Key technologies supported include 3G, 4G/LTE, IMS, Ethernet, OTN, FTTx, and various optical technologies (accounting for an estimated 35% of the portable fiber optic test market). For more information, visit www.exfo.com.

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