Ensuring IPTV Service Quality

Current telecommunication, broadcast, and Internet networks are not meeting the needs of modern information society. Resources are limited, transfer efficiency is low, and technology that is customized for operators is sometimes limiting for users. Integrating different technologies of three networks, IPTV offers the best triple play solution. By 2011, IPTV was widely deployed throughout China. In some provinces, up to 4 million people are using IPTV and this has put great pressure on telecom operators. To provide better end-to-end service, telecom operators are seeking a highly efficient way to solve the problems in IPTV.

Because of the great number of IPTV users, faults sometimes arise in the access network, service platform, and in playback. Users sometimes complain of no IPTV program or video lag. Such problems happen in the home, and it is difficult to precisely locate and test for faults. Resolving lag in a program involves different departments performing manual operations and analyzing data. Maintenance personnel may even need to come into user's home for troubleshooting. Therefore, IPTV service quality management is very important.

IPTV Service Quality Mode and Management Solution

At present, no international organization has clearly defined standards for IPTV service quality. The ITU is working on IPTV GSI to promote global standardization of IPTV. IPTV GSI uses the QoE definition given in ITU-T P.10/G.100. QoE consists of subjective quality evaluation and objective quality evaluation. In the former, video quality is evaluated through visual systems and subjective feeling; in the later, objective indicators and testing tools are used for evaluation.

Operators are increasingly concerned with defining and quantifying IPTV service quality and creating an IPTV service quality index that can be referred to for network OAM. A quality evaluation mode based on the technology link in IPTV is needed.

Mean opinion score can be used to evaluate video quality according to user experience. It has a five-point scale: 5 is excellent, 4 is good, 3 is fair, 2 is poor, and 1 is unsatisfactory.

Service quality management can be used to measure IPTV service quality and help operators locate problems. SQM comprises three main methods:

• Monitoring point probe: Monitoring point probes are installed at both terminals of an IPTV system to continuously test and monitor target links. QoS and QoE faults can be efficiently located and accurate data about the faults can be obtained. However, this is costly, and there is heavy workload involved in deployment and maintenance. There are also blind spots.
• Terminal probe and data deduction: Probes are installed at the terminal to periodically collect network and video data from the STB as well as service quality data from users and network segments. Then the system analyzes the data according to topology data of the access network. When service appears to be abnormal, the system deduces where the fault is occurring according to topology data. This is relatively simple and less costly, but faults cannot be found at the headend, internal and output of the IPTV service platform.
• Tools: Tools can be used to locate problems in IPTV system links, but these are only auxiliary. Whole faults still need to be located by technicians themselves.

IQAS Ensures IPTV Service Quality

Knowing the defects of these solutions and software tools, ZTE has created an IPTV QoS Assurance System (IQAS). IQAS combines the advantages of three main solutions in order to monitor service quality and locate faults in head-end, IPTV service system, network, and user end. The solution is built on the existing IPTV system, and this reduces deployment workload and MAO costs to the greatest possible extent.

IQAS monitors QoS data at the head-end, service platform and user end by deploying probes. It deduces network faults using an expert database and logical calculation. It also analyzes user signaling faults using protocol tracking function and locates faults using software tools.

QoS monitoring and fault location in the head-end system and IPTV service platform

IQAS monitors the quality of head-end video steam and network QoS through monitoring points in the head-end multicast channel. Multicast channel stream monitoring points, which are required by the IPTV system and node side, can detect media being exported from the IPTV platform and can obtain the relevant network performance index. All probes at the monitoring points can be applied to platforms and terminal equipment of various manufacturers. This helps OAM technicians find content or platform faults as they occur, and this prevents UE from being negatively affected and reduces user complaints.

Monitoring and locating network service quality faults

IQAS has an expert system and reasoning function that is connected to the synchronous network topological data of an operator’s IT system. It combines an advanced knowledge base and reasoning machine. In the case of abnormal service, the system can promptly locate and monitor network faults. The knowledge base and reasoning function is continually upgraded so that faults are located with high precision. These functions avoid the need to deploy large numbers of probes in the access network and bearer network. They reduce cost and maintenance difficulty and eliminate dead zones that exist in the monitoring point probe function.

User-end QoS monitoring and fault locating

IQAS has monitoring points embedded in user terminals. These points record playback history and original service quality data. If the access is abnormal, for example, the wrong service account is accessed, or QoS is abnormal, for example, media loss rate exceeds the threshold value, IQAS automatically sends an alarm. For VIP users, IQAS has 24/7 QoS data collection so that the requirements of the SLA are met.

Signal tracing

IQAS collects signals through a standard interface in the IPTV service system and can trace the signals of specified users in the IPTV network. Signaling messages help OAM technicians analyze the service workflow of STB (that is, booting, authentication, subscription and VOD/TVOD/TSTV).

IQAS also has excellent STB management function. IQAS includes the asynchronous communication server function found in terminal management, and STBs and home gateway equipment can be remotely managed according to the TR-069 protocol. The terminal management function meets the management standards and expansion demands of China Telecom and China Unicom. Any STB that supports the TR-069 standard and relevant operator standards can be remotely managed.

IQAS also provides STB playback testing tools that can be used for remote control, testing STB, and monitoring EPG pages, channels and VOD programs. IQAS provides tools for capturing live channel or VOD specified by the media sever. These tools can be used to analyze program code and corresponding network quality. IQAS has STB protocol-analysis tools that can be used to obtain detailed protocol interactive LOG. This helps OAM technicians deal with service problems. With IQAS expert tools, technicians can solve all service quality faults efficiently.

IPTV operation, maintenance, and fault location are headaches for telecom operators. ZTE IQAS greatly enhances the ability of operators to offer IPTV service support. The system has already been adopted by commercial IPTV networks in America, Vietnam, Singapore, Russia, Indonesia, and China.