Research and Application of IPTV access network solution (1)

1. IPTV is a good choice for developing video services

1.1 IPTV meaning

IPTVInternet protocol television) refers to the use of broadband network infrastructure, with computer PC) or "ordinary TV + network set-top box TV + IPSTB)" as the main terminal device, provide users with new technologies based on video content applications, such as live TV and on-demand video. [1]

1.2 Development of IPTV

As the Internet advances to the Broadband Age, Internet technologies and applications are increasingly integrated into the lives, entertainment and work of domestic consumers. The bright future of broadband Internet applications leads the world's telecom industry to increase the R & D, cultivation, and market promotion of Internet application content. IPTV can free people from the time constraints imposed by traditional radio and television, this enables TV personalization and interaction to be truly realized.

For domestic fixed network operators, the development of IPTV services has a variety of internal and external driving forces:

1) traditional telecom services continue to decline, and new value-added channels of video services have become a good choice for sustainable development;

2) relying solely on Internet services, due to its lack of content and poor profitability, you may wish to make full use of its existing broadband network advantages to provide the original driving force for the development of IPTV services;

3) from the perspective of evolution and development of NGN, IPTV is a typical business in the future and has great industrial development prospects [2];

4) due to the optimistic development trend of IPTV services carried out by some fixed network operators abroad, domestic and foreign equipment providers and content providers have invested a lot of manpower and financial resources, and the industrial environment has begun to take shape, enhanced the confidence and determination of fixed network operators to get involved in IPTV.

One of the main features of IPTV is its real-time broadband interaction, which makes it different from traditional cable TV and conventional digital TV. IPTV allows users to choose diverse, easy-to-use, and personalized interactive multimedia services at any time without time restrictions, and supports various effective broadband access, high-speed access technologies such as xDSL, LAN, FTTH/FTTP Optical Fiber-to-home/Optical Fiber-to-station), and WiMAX to maximize the convenience of personalized broadband applications.

2. Challenges of IPTV services to existing access networks

2.1 network requirements of IPTV services

The IPTV service mainly provides users with high-quality digital audio and video services, which have high requirements on the image effect. Therefore, the image quality needs to be controlled. The video signal rate determines the quality grade of IPTV images. The higher the speed, the higher the image quality grade, and the higher the bandwidth requirement.

HD: high definition) or SD: standard definition) Quality uncompress digital videos in IPTV services can be transmitted at dozens of Mbit/s, videos must be compressed to reduce transmission bandwidth and storage requirements. The selection of video compression encoding technology determines the bandwidth requirements of IPTV service users. Currently, MPEG4 and H.264 are the two mainstream technologies used in the industry. The MPEG4 format encoding scheme provides SD quality programs. Generally, the customer needs to activate 3 Mbit/s or more broadband, and there is almost no possibility of improvement. the 264 format encoding scheme provides the corresponding quality program. Generally, You need to activate a bandwidth of more than 1.5 Mbit/s for the customer. 264 the development of coding technology is expected to develop below 1 Mbit/s to provide SD images of DVD quality.

Based on the analysis of the above two types of codes, IPTV users generally require at least 1.5 Mbit/s of bandwidth when receiving video stream data, in addition to the protocol encapsulation overhead of 10%-20%, signaling control channel traffic, and appropriate IP fluctuation margin, we recommend that each IPTV user plan bandwidth above 2 Mbit/s.

The IPTV platform bearer network should first ensure the availability of IPTV services, that is, users who pass authentication can use services anytime and anywhere. Secondly, ensure that the service response time is within the tolerable range of users, this prevents you from giving up your business because of the long connection time. Once again, you must ensure the intuitive effect of your business, especially the definition and smoothness of audio and video services. These requirements are reflected at the bearer network level, that is, the requirements for bandwidth, network latency, jitter, packet loss and reliability. Sufficient bandwidth is the basic condition for providing good service quality. The three network parameters of latency, jitter, and packet loss are the most basic network layer QoS indicators. In addition, the network must provide effective reliability, in the case of a link or node failure, it is necessary to promptly detect and take appropriate measures to ensure uninterrupted or rapid restart of services.