 | Issue: | EMEA 2006 |
| Article no.: | 10 | |
| Topic: | The IPTV quality challenge | |
| Author: | Peter Collingwood | |
| Title: | Regional Vice President, Europe, Middle East & Africa | |
| Organisation: | JDSU Communications Test division | |
| PDF size: | 448KB |
About author
Peter Collingwood is Regional Vice President, Europe, and Middle East & Africa for JDSU’s Communications Test division (formerly Acterna). Mr Collingwood has been with the organization for over 18 years and has served in senior level corporate positions in Europe and the United States. Mr Collingwood holds a Bachelor of Science Electronics Engineering and Diploma in Industrial Studies from Loughborough University of Technology.
Article abstract
Triple play, the combination of voice, data and video, is the package service providers need to compete in the marketplace today. The changeover from traditional telephony calls for more than just upgrading the network to transmit a TV signal. Video quality requirements are quite different from those for voice and data – and significantly more difficult to maintain. Subscriber satisfaction and retention depends upon quality of service, reduced installation and support problems, and constant end-to-end testing to guarantee high-quality reception.
Full Article
Across all segments of the market – from R&D labs to customers’ homes – triple-play services delivery is raising expectations. Equipment manufacturers envision a strong return from network build out. Service providers hope to regain or increase average revenue per user, ARPU, by entering this new market. Most importantly, consumers anticipate a broader range of service options and features at a competitive price. Confidence is also high in all segments. With great strides made in broadband voice and data, the market is poised for video-Internet Protocol Television, IPTV, but to make the triple play happen, efficient deployment is crucial. Successful widespread IPTV adoption will hinge on a precise balance between rapid service delivery and on-going outstanding quality of service, QoS. Close attention to a quality installation and service assurance strategy that significantly reduces or eliminates early installation failures is key to striking this balance and, ultimately, unleashing the full potential of the voice, video and data bundle. Demanding audience In the home consumer arena, TV is a highly ‘emotional’ medium. Anticipation for a particular show or event can build for days, weeks and even entire seasons. When the awaited time arrives, viewers want a flawless entertainment experience, one where the delivery service performs perfectly and invisibly. This expectation stems partially from customer experience with the solid reliability of installed terrestrial and satellite broadcast systems. In the IPTV market, the expectation is magnified by the consumer trend toward high-definition entertainment systems. As pace setters allocate increasing portions of their entertainment budgets to home theatre gadgetry, investments are climbing well into the thousands for high-resolution TVs and digital surround sound systems. Consumers’ quality of experience, QoE, expectations are growing exponentially as well. Consumers are embracing IPTV as the revolutionary service delivery mechanism that will showcase the full potential of their home system investments. These early adopters will not settle for service delivery that does not yield maximum satisfaction in the form of total quality entertainment, and they will not wait patiently for problem resolution. Providers may have only one chance to get the service right, or lose the customer. Sophisticated and educated, these consumers will demand near-immediate turn-up, expect perfect service performance from day one, and readily churn to the competition when they do not receive it. Complex service, complex infrastructure Understanding the complexity of deploying an IPTV service that will meet these high expectations begins with an understanding of the service itself. IPTV is not simply television over the Internet. Rather, it includes live and broadcast TV as well as high-end options such as video-on-demand, VoD, content and live pause/rewind/fast forward programme control functionality. The service is delivered using Internet protocol over private networks with broadband connections, either through a PC connected to the TV or a set-top box, STB. The STB is a device that contains a small computer to decode the entertainment media data stream and let customers choose and manipulate content for immediate and future viewing. Differing from terrestrial or satellite delivery mechanisms, IPTV communication goes beyond sending a selection and receiving the content. IPTV can include two-way interactive communication applications such as gaming, distance learning or video conferencing. By fully utilizing the high-speed functionality of the broadband infrastructure, IPTV gives the consumer greater control over content by establishing viewing schedules for stored content or selecting viewing sequences for broadcast video. For service providers, delivering this enhanced capability comes at the price of implementing new technologies and managing more complex networks. IPTV is made possible through the advent of technology and protocols to send high-speed transmissions reliably over myriad existing and emerging infrastructures. ADSL2+ and VDSL (new higher speed versions of digital subscriber lines, DSL) are enabling providers to maximize existing copper, while the on-going build-out of optical fibre to the network edge, FTTx, is bringing vast potential for new service delivery. The building blocks that form the network infrastructure for IPTV are the same as those that form the foundation for VoIP and high-speed data delivery. (See Figure: Building Blocks of Triple Play) With the addition of a video head end – the main facility for generating IPTV system signals – providers prepare media streams to travel through their distribution and access networks to the customer’s home, and the in-home distribution network. However, unlike VoIP and data services, IPTV requires continuous, in-depth testing and monitoring of the network infrastructure as well as proactive intervention to maintain the quality of the data travelling on it. New testing considerations Acknowledging the sheer complexity of IPTV deployment is the provider’s first step toward successful service rollout. Comprehensive planning for its unique test and measurement needs is the next. Bringing video flows online on a network already carrying data and voice traffic greatly increases bandwidth demands on the infrastructure. The dynamic nature of video – with its frequent and rapid channel changing and VoD requests, for example – is an issue that providers have not addressed previously in meeting voice and data class of service, CoS, parameters. In addition, traditional transport or access test equipment that may already be in place on a network cannot reliably test IPTV. The existing test solutions cannot delve into IPTV’s application-specific QoS metrics or resolve trouble before it affects customer service. (See Sidebar/ Photo: What’s wrong with this picture?) Essentially, each sector of the service delivery network – head end, distribution, access and in-home – needs IPTV-specific test solutions. Transport and access testing are familiar tasks for service providers, but what is standard for traditional services has been re-defined for triple play. Copper and fibre qualification take on new significance when preparing the physical plant to support the increased bandwidth required by simultaneous delivery of voice, video and data. As data rates continue to increase, use of wider frequency spectrums is required. This, in turn, means field technicians must carry a new class of tool capable of testing to new and more exacting specifications. With triple play, the access loop no longer ends at the network interface device outside the customer’s house, it extends throughout the in-home distribution network and so, here too, a new set of tools is required. Good planning can assimilate these refinements to transport and access testing strategy as extensions of existing practices. Where the dramatic difference in needs and approach occurs is the digital video testing aspect. Service providers deploying IPTV face entirely new test methodologies and service assurance challenges. While digital video testing has many facets, the most important to consider is ensuring stream composition integrity. Systems and tools that maintain timing and synchronization accuracy, assure audio/visual quality, and maintain compliance with broadcasting industry standards accomplish this. The digital transport stream that brings IPTV service to customers’ homes is different in structure and composition than the other data and signals travelling over the broadband network. Quality video stream content begins at the packet level, in the head end. Governed by MPEG-2 standards, each packet in the transport stream is coded at the head end with extensive information needed to ensure QoS at its destination. Each packet must accurately retain this information as it moves through the distribution, access and home networks to the customer’s STB. The video stream is comprised of an endless flow of these packets, each carrying combined digital and audio payloads, and there are often multiple programmes on each stream. To sort the millions of packets, and arrange them to display synchronized sound and pictures, the stream carries an encoded map of the incoming content that directs the STB decoding process. In addition, an MPEG transport stream may include tables that list subscription and pay-per-view options as well as data for electronic programme guides. Of concern for providers is that the complex contents of these flows have less tolerance for packet loss and jitter. Consequently, IPTV service requires distribution and access networks to perform to higher standards. With this reduced tolerance, each IPTV data packet travelling across the network introduces the potential for error – error that will compromise viewing quality and erode the customer’s confidence in, and loyalty to, the service provider. These errors can be tremendously difficult to locate and resolve. Lacking the appropriate equipment, technicians might spend days sectionalizing MPEG transport layer problems, since these errors frequently cannot be detected on the IP layer. To effectively diminish this and other troubleshooting difficulties, providers can employ a comprehensive centralized digital video test system. Such a system looks into all IPTV data flows simultaneously, interprets stream maps and tables, and presents the results in a manner that lets the technicians assess easily the health of the stream. Then, actions can be taken, remotely if needed, to ensure high QoS. It is important to note that bringing the service to the customer’s door is not where the IPTV service delivery challenge ends. IPTV service has unique in-home network testing considerations as well. When field personnel are dispatched to a residence, the service costs rise sharply if the technician cannot complete the job in one visit. The technician must carry tools that will emulate the customer’s STB to obtain and validate the video programme flows and QoS values that have been established by the service provider. Additionally, the technician may need tools to test the in-home distribution network if acceptable service quality cannot be verified. Multiple visits with poor quality service, or no service, will not please the discriminating customer. A matter of timing Buying trends show that consumers are ready to invest in new services. Market research reports show that all major telecom providers and multiple service organizations are building out to claim a share of the IPTV services delivery profits. The data supports the rationale – never before has there been a situation where attention to test and measurement was so vital to realizing the potential of a new service opportunity. Informed providers will make the investment. Those who do not will be quickly passed as their well-prepared competitors barrel ahead with the trend. Faulty IPTV data transmission can leave the customer with unacceptable picture quality. This is particularly true with flat-screen high definition TVs, a minute error can yield huge complications including loss of audio, lip sync errors, blocking, tiling or freezing. Diagnosis for these problems is complex – one or a multitude of network conditions could result in garbled or missing sound and poor-quality images. Jitter on the line, packet loss and faulty synchronization are only a few of the conditions that can give way to unacceptable QoS. Using traditional test methods to measure IP parameters, a technician may find transport network performance to be within acceptable levels, yet QoS is not. Drilling down into the IP transport stream is the first level of problem solving, but to resolve QoS issues for IPTV, the technician must be able to delve into the MPEG transport stream. Whether turning up IPTV service or responding to a trouble call, technicians must carry instruments that not only verify service quality and IP transport parameters from the demarcation point, but verifies that the customer will be able to change channels and take advantage of fee-based services as well. To retain customers and decrease repeat service calls, the provider must ultimately employ tools to verify content stream integrity and a centralized, application-aware, service assurance system to prevent errors that occur on the network from affecting the customer’s QoS.
