Since IPTV entered the market in 1999, the growth rate has gradually accelerated. It is expected that the global IPTV users will reach more than 26 million by 2008, and the compound annual growth rate of IPTV users in China from 2003 to 2008 will reach 245%.
According to the survey, the last kilometer of IPTV access is commonly used in DSL cable access mode, by the bandwidth and stability and other factors, IPTV in the competition with ordinary TV is at a disadvantage, and the cable access mode of construction of the cost is high, the cycle is long, and difficult. Therefore, how to solve the last-mile access problem of IPTV is particularly important.
WiMAX (WorldwideInteroper-abilityforMicrowave Access) is a broadband wireless access technology based on IEEE802.16 series of protocols, which has gradually become a new development hotspot for metro broadband wireless technology. It can replace the existing DSL and wired connections to provide fixed, mobile forms of wireless broadband connections. Due to its low construction cost, high technical performance and high reliability, it will be a better technology to solve the last-mile access problem of IPTV.
2, the current situation of IPTV access technology
Currently, the commonly used access technologies to provide IPTV services include high-speed DSL, FTTB, FTTH and other wireline access technologies. Because of the low investment in using the existing DSL system to support IPTV services, 3/4 of the telecom operators in Asia use set-top boxes to convert DSL signals into TV signals to provide IPTV services.
The most important contents of IPTV bearer include VOD and TV programs. In order to ensure that the viewing quality of IPTV is comparable to that of the current cable network, IPTV bearer network is required to provide guarantees in bandwidth, channel switching delay, network QoS, etc., and these aspects of the DSL technology are unable to meet the requirements of IPTV, and the DSL support for multicast is limited. IPv4 protocol routers, do not support multicast. Although theoretically there is still room for upgrading DSL technology, there are few qualitative changes in bandwidth.
3, the characteristics of WiMAX technology
WiMAX is a broadband wireless access technology based on the IEEE802.16 standard, which is a new air interface standard proposed for microwave and millimeter wave bands. It can provide up to 75Mbit/s transmission rate, single base station coverage up to 50km. WiMAX is designed for wireless LANs and to solve the problem of the last mile of broadband access, it is used to connect Wi-Fi “hotspots” to the Internet, but also to connect the environment of the company or home to the wired backbone line, which can be used as a cable and a DTH line, and can be used as the cable and the DTH line. It can also be used to connect environments such as a business or home to a wired backbone, and can be used as a wireless extension to cable and DSL to enable wireless broadband access.
4、WiMAX realize wireless access of IPTV
(1) Requirements of IPTV on access network
The main feature of IPTV service is its interactivity and real-time. Through IPTV service, users can enjoy high-quality (close to the DVD level) digital media services, and can freely choose video programs from broadband IP networks, realizing substantial interaction between media providers and media consumers.
In order to ensure that the viewing quality of IPTV is comparable to that of the current cable network, the IPTV access network is required to be able to provide guarantees in terms of bandwidth, channel switching latency, network QoS, and so on. In terms of user access bandwidth, the use of existing widely used coding technology, users need at least 3 ~ 4Mbit / s downlink access bandwidth, if the transmission of higher quality video, the required bandwidth is also higher; in the channel switching delay, in order to ensure that IPTV users switch between different channels and ordinary TV switching the same performance, the widespread deployment of IPTV services require at least digital Subscriber line access multiplexing equipment (DSLAM) to support IP multicast technology; in terms of network QoS, to prevent packet loss, jitter and other impact on the quality of IPTV viewing.
(2) Comparison of WiMAX access method with DSL, Wi-Fi and FTTx access method
DSL, due to its own technical constraints, there are still many problems in terms of distance, rate and outgoing rate. Compared with DSL, WiMAX can theoretically cover a larger area, provide faster data rates, have greater scalability and higher QoS guarantees.
Compared with Wi-Fi, WiMAX has the technical advantages of wider coverage, wider band adaptation, stronger scalability, higher QoS and security, etc. Wi-Fi is based on the Wireless Local Area Network (WLAN) standard, and is mainly used for proximity-distributed Internet/Intranet access indoors, in offices, or hotspot areas; WiMAX is based on the Wireless WiMAX is based on wireless metropolitan area network (WMAN) standard, which is mainly used for high-speed data access service under fixed and low-speed mobile.
FTTB+LAN, as a high-speed broadband access method, carries out IPTV service without much problem technically, but it is limited by the problem of integrated wiring in the building, installation cost and transmission distance caused by twisted-pair cable. WiMAX's ideal non-line-of-sight transmission characteristics, flexible deployment and configuration scalability, excellent QoS quality of service and strong security all make it an ideal access method for IPTV.
(3) Advantages of WiMAX in realizing wireless access to IPTV
By comparing WiMAX with DSL, Wi-Fi and FTTx, it can be seen that WiMAX is the better choice in realizing IPTV access. As of May 2006, the number of WiMAX Forum members grew to 356, and more than 120 operators around the world have joined the organization. WiMAX will be the ideal technology to solve the last mile of IPTV. WiMAX will also be a better alternative to DSL and Wi-Fi.
(4) WiMAX Realization of IPTV Access
IEEE802.16-2004 standard is mainly oriented to fixed terminals, the maximum transmission distance is 7~10km, and its communication band is lower than 11GHz, adopting the optional channel method, and the bandwidth of each channel is between 1.25~20MHz. When the bandwidth is 20 MHz, the maximum rate of IEEE 802.16a can reach 75 Mbit/s, generally 40 Mbit/s; when the bandwidth is 10 MHz, it can provide an average transmission rate of 20 Mbit/s.
WiMAX networks support colorful business models. Data services of different rates are the main target of the network.WiMAX supports different QoS levels, so the network coverage is closely related to the type of service. In terms of IPTV access. because IPTV requires high-level QoS assurance and high-speed data transmission rates. so the WiMAX network is set up reasonably according to the number of users in the area and their needs. When users access the IPTV network. There is no need to carry out wiring again, only need to add WiMAX receiving equipment and IP set-top box, so users can use IPTV service conveniently and quickly.
At present, IPTV is an emerging business with great market potential, and its development is still in its infancy. The trend of its future development is to further integrate IPTV services with terminals, and TV will become a comprehensive digital home terminal with communication and Internet functions. But IPTV to achieve a breakthrough in the true sense, not only to solve the content problem, but also to solve the bottleneck of the last kilometer.
Post time: Dec-05-2024