Comprehensive application of WiMAX in IPTV Access Networks

IPTV access networks are quite common. So I have studied the comprehensive application of WiMAX in IPTV access networks. Here I will share with you, hoping it will be useful to you. The MAC layer of the WiMAX system (including 802.16e and 802.16-2004) features connection-oriented, that is, all services (including those without connection) in the 802.16 system, the CID ing is mapped to the connection. Each connection has a 16-bit connection flag (CID) as the unique identifier.

The MAC layer of WiMAX defines a comprehensive QoS mechanism. The MAC layer sets different QoS parameters for each connection, including the rate and latency. To better control the bandwidth allocation of Upstream data, different upstream bandwidth scheduling modes are defined, the fixed bit rate and Variable Bit Rate features different scheduling mechanisms to achieve flexible bandwidth allocation. The MAC layer supports both point-to-point (PMP) and Mesh structures, and supports continuous and burst services, including voice, data, IP connection, and VoIP. In order to solve the instability of wireless transmission environment, MAC layer adopts Wireless Link adaptive technology, ARQ and H-ARQ technology to ensure the reliability and effectiveness of information transmission. On the basis of IEEE802.16-2004, many new features are introduced in MAC layer. It mainly includes three aspects: Switching Technology, power-saving functions, and security capabilities.

IPTV System Model Based on WiMAX access

WiMAX-based IPTV access network functions, including VideoServer, VideoRouter/switcher, user base station (SS), base station (BS), and terminal. Video Server (VideoServer): stores audio and video content, which is obtained from pre-recorded program compression encoding and then provides services to users. Video Servers can be distributed in the core network in a centralized or distributed manner. VideoRouter/Switcher: Provides route access from the video server to the IP network. User base station (SS): a type of base station that provides a relay connection between the base station and the user terminal. It is usually installed on the roof of the residential area using a fixed antenna. The dynamic adaptive signal modulation mode is used between the base station and the user base station. Base station (BS): The base station provides the connection between the user base station and the IP network. Generally, slice-shaped or omnidirectional antennas are used to provide flexible sub-channel deployment and configuration functions, and constantly upgrade and expand the network according to the user group situation. Terminal: The WiMAX system defines the connection interfaces between user terminal devices and user base stations, and provides IPTV access networks for user terminal devices.

The voice video content is first compressed and encoded (mostly using MPEG-2), and then encapsulated by real-time transmission protocol (RTP, finally, it is encapsulated by the IP protocol and the Ethernet 802.3 protocol and then transmitted in the core network. After the WiMAX base station at the edge of the core network receives the 802.3 protocol package, the MAC layer of the base station unpacks the package and removes the Ethernet protocol header, then it is encapsulated into the MAC layer grouping data unit and the PHY layer data unit of the 802.16 protocol. The physical layer uses forward correction encoding (FEC), symbol ing, OFDM modulation, and other technologies to prepare wireless air connections for data units. The radio transceiver sends signals to the SS or BS through an antenna. After the SS and BS receive signals, the signal is restored to the desired audio and video content through the inverse process in the preceding process.

Advantages of WiMAX as an IPTV Access Network

As an IPTV access network solution, WiMAX has the following advantages: convenient and flexible network construction. First, WiMAX, as a broadband IPTV access network application, has the characteristics of gradual investment and elastic deployment. network operators can gradually increase investment and gradually expand their capacity according to the needs of user capacity growth, achieve a relatively smooth cost curve. Secondly, network planning is not restricted by terrain and topography, and is flexible in ministries and bureaus. At the same time, areas with low user density can still achieve low-cost coverage, reducing the risk of initial investment. Once again, the network deployment is fast and easy to install and resize.

High bandwidth, large capacity, and long transmission distance. The WiMAX operating frequency ranges from 2 ~ 66 GHz, with a channel bandwidth of 1.5 ~ Flexible adjustment within the range of 20 MHz is conducive to making full use of spectrum resources in the allocated channel bandwidth. WiMAX uses a macro-cell mode with a maximum coverage of 50 km. When the channel bandwidth is 20 MHz, it supports a shared data transmission rate of up to 70 Mbit/s (in this case, the maximum coverage radius is 3 ~ 5 km ). Multi-sector technology can be used to increase system capacity. One sector can support more than 60 enterprise users or hundreds of home users using the E1/T1 interface at the same time. WiMAX uses a variety of advanced technologies such as OFDM, receiver/sender diversity, and adaptive modulation to achieve NLOS and block line of sight ONLOS transmission, effectively improving the transmission efficiency.