Ensuring Quality of Experience: A Key Competitive Advantage

By Steve Liu, Mixed Signals

Ensuring superior quality of experience (QoE) for cable subscribers is vital as competition continues to increase with satellite and IPTV providers.

When companies compete, they win customers through product/service differentiation or price or both. Not surprisingly, rather than enter a price war, cable, satellite and IPTV providers are working hard to present a differentiated product to consumers. Certainly, with its large, embedded infrastructure, cable has a leg up today, and all are adding popular SD and HD channels. Service quality and uptime, however, is rapidly becoming a key differentiator in the competition for subscribers - one that all providers are focused on.

With higher monthly bills for TV service and the proliferation of larger HDTVs, subscribers demand more, and providers risk losing them if experiences are marred by digital video, audio and other QoE service impairments. The irony is that many QoE issues are indirectly caused by the new services being added, which require new equipment and increase network complexity.

Issues that spark service outages and quality issues begin before the content is received by the providers and are then exacerbated by the ever-increasing complexity of the provider infrastructure. The key to service assurance, a high level of QoE and ultimately lower operational expenditures, is to fully understand the integrity of all content being delivered to subscribers. Problems with video and audio content ultimately lead to calls from subscribers, truck rolls and deployment of technicians to resolve issues.

Fortunately, operators have powerful new tools that give them real-time insight into their networks, at both a high-level "big picture" view and a very granular look at each program stream simultaneously. This gives operators tremendous new abilities to discover, diagnose and rectify QoE issues.

There are three key components of an effective monitoring system. First, it must include real-time detection and alerting on a comprehensive list of common service impairments (e.g., video black/freeze and audio silence) in various layers at the content level. This cannot be accomplished by analyzing network activity. Second, it needs to perform real-time inspection of all programs without sampling or skipping, which is key to quickly discovering any subscriber-impacting anomalies when they happen. This also is critical to the detection of intermittent quality issues. Finally, the monitoring system should provide historical reporting and analysis tools to aid problem isolation and root cause analysis, which reduce the time required to detect and repair issues that will ultimately reduce operational costs.

Packet Content Inspection Completes the Picture

In an attempt to simplify issues found in their complex architectures, many operators often employ probe-based solutions and limited scoring mechanisms. While this is helpful as part of a QoE effort, there are inherent limitations to this approach. While some probes can tell if the packets are coming through, they cannot identify service quality issues within the packets themselves. Here's a simple analogy: a fragile item is shipped cross-country in a box, arriving on schedule but with the contents broken. The packets may arrive OK, but the content is impaired and a large number of subscribers may experience error blocking, tiling, a frozen screen, black video, audio problems and even service outages.

Complementing network probes are packet content inspection techniques that enable operators for the first time to identify chronic, hard-to-find problems by taking into account (MPEG) packet content impairments. Comprehensive QoE assurance requires packet-by-packet content inspection across all services. (Refer to the diagram below.)

It's a 24x7 Real-Time Challenge

Quality issues and outages are unpredictable, especially in today's highly complex digital video processing world. To find problems when they happen, operators must implement a monitoring system that reports impairments in real time. While sampling approaches, in which monitoring program streams is done on a scheduled basis, are better than no monitoring, 24x7 "round the clock" real-time monitoring is essential for ensuring QoE across all services.

Additionally, some operators use offline analysis techniques in which screen/video captures of QoE disruptions are analyzed after the events. Again, while somewhat helpful, this approach is, by its nature, "after the fact" and not a substitute for real-time detection and troubleshooting.

The supposed cost savings of sampling approaches and offline analysis may be attractive, but also quickly offset by continuous subscriber complaints resulting from intermittent problems that come and go across multiple programs.

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Historical Analysis

The full-time and real-time monitoring of all programs and services content for problems is crucial. However, historical reporting and analysis tools also are needed to reduce recovery time.

As video processing and service delivery become more sophisticated, QoE assurance has also become more challenging as the processing and interaction among receivers, multiplexers, switches, splicer, encoders, servers, modulators, set-top boxes and other myriad devices can result in severe errors. These are often difficult to troubleshoot and to determine the root cause of unless comprehensive "historical" reports are provided to allow operators to perform a "turn-back-the-clock" analysis.

For example, whenever an alert is fired, an operator must often compare and contrast multiple time-based reports dealing with bandwidth, discontinuities, IP network jitter, tables and digital program insertion across different programs, transport streams, or even various geographical locations, in order to isolate and pinpoint causes.

Identifying the root cause of these - and many more - complex errors is by its nature complex, and it is here that historical information plays a critical role. It allows operators to conduct "go-back-in-time" troubleshooting and to narrow in on possible causes quickly - in most cases in a matter of minutes. The value of combining alert triggering and detailed historical reports to conduct timely and accurate troubleshooting and root cause analysis is both obvious and compelling.

The historical report by itself is also a good trending indication of the overall health of MPEG services and the (IP) network.

Conclusion

A comprehensive video service quality effort requires operators to perform a deep inspection at different layers in the content level, continuously monitor programs 24x7 and generate historical reports to provide the information to perform effective troubleshooting and improve service quality. When done properly, this comprehensive approach can dramatically improve operational efficiency and QoE, which is vital to combating subscriber churn and its associated costs.

Steve Liu is director of product management at Mixed Signals.

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