Application and Implementation of Security Broadcasting in CMMB Terminal
Principle and application of safety broadcasting The safe broadcast technology inserts the safe broadcast information into the mobile multimedia broadcast signal, so that the mobile multimedia terminal has the ability to identify the legality of the multimedia broadcast service. That is, when the mobile multimedia broadcast is maliciously replaced or tampered with during the transmission process, the terminal can stop illegal business presentation in time. The safety broadcast front-end subsystem obtains the multiplexing control information table and service feature information, and generates safety broadcasting information based on these information, and multiplexes and transmits in the form of data services. The multiplexing subsystem uses separate multiplexing subframes to carry safety broadcast information, assigns a service identification number to it, and sends it via the broadcast channel. When the terminal receives the mobile multimedia broadcast service content, the safety broadcast terminal module demultiplexes the transmission frame to obtain the safety broadcast information according to the service identification number, and verifies the safety broadcast information, and confirms the legality of the broadcast service content according to the verification result To allow or prohibit business presentation. The role of safety broadcasting Compared with traditional TV, CMMB can not only broadcast audio and video programs, but also use its own bandwidth advantages to provide various data services, including traffic guidance, stock market quotes, electronic magazines, life consultation, push downloads, etc. Through the backhaul of the mobile communication network, the CMMB terminal can also realize functions such as interaction and online payment. Of course, such diverse applications must be secured by a secure network. Imagine that if there is no safe broadcast, criminals may use high-power mobile transmitters to carry out illegal broadcasts in areas where CMMB terminals are concentrated in order to achieve personal purposes. At this time, the interfered terminals will receive poison from illegal radio stations. TV programs thought by viewers, or TV shopping channels whose contact phone numbers and bank account numbers have been tampered with, are not only hurting consumers but also operators. The goal of the State Administration of Radio, Film and Television is to set up a mobile radio and television system of “integration of heaven and earth, combination of satellite and network, unified standards, and national roamingâ€. With direct control, illegal signals can be covered nationwide. Of course, this is just a hypothesis, but secure broadcast technology can guarantee that this hypothesis can never be established. Tsinghua Tongfang Electronic Equipment Co., Ltd. launched the TF376 security chip solution based on the "Safety Broadcast" standard. By using the TF376 scheme, terminal manufacturers can realize the safety broadcast function in the shortest time, and can easily realize the CA function of the SMD method. For TD-SCDMA terminals using MBBMS, the hardware connection shown in the figure below can be used. Shanghai Fengbao Electronic Technology Co., Ltd. began to pay attention to the CMMB industry since 2006, and actively cooperates with Tsinghua Tongfang Electronic Equipment Co., Ltd. to provide CMMB terminal manufacturers with a secure broadcast + CA solution. The products of many existing terminal manufacturers have been mass-produced and listed . This solution is suitable for various types of platforms and can assist terminal manufacturers to complete the safety broadcast and CA functions in the shortest time. At the same time, TF376 has a built-in UnionPay payment module, which can facilitate the payment problem of CMMB terminals and facilitate operators to develop various value-added service applications. Shanghai Fengbao Electronic Technology Co., Ltd. cooperated with Tsinghua Tongfang Electronic Equipment Co., Ltd. and Shanghai Jingda Digital to develop the world ’s first USB Dongle solution with built-in SMD CA and safety broadcasting. Mass production has been achieved. funcTIon ImgZoom (Id) // Re-set the image size to prevent the form from being broken {var w = $ (Id) .width; var m = 550; if (w <m) {return;} else {var h = $ (Id) .height; $ (Id) .height = parseInt (h * m / w); $ (Id) .width = m;}} window.onload = funcTIon () {var Imgs = $ ("content"). getElementsByTagName ( "img"); var i = 0; for (; i Hengstar provides a range of Industrial Fanless Pc for industrial automation environments. 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The safety broadcasting system is composed of a front-end subsystem and a terminal module. The front-end subsystem realizes the generation and transmission of safety broadcasting information, and the terminal module realizes the reception and processing of safety broadcasting information. 
Realization of safety broadcasting in CMMB terminal 
The picture above is the hardware connection diagram of TF376 in the CMMB terminal. TF376 is connected to the terminal's AP (application processor) or CP (coprocessor) through the UART interface, and Nagra's SMD CA chip is connected to TF376 through the 7816 interface. When the CMMB terminal system works, the AP or CP demultiplexes the received CMMB code stream to obtain a multiplexed frame, and transmits the multiplexed frame to the TF376 software module. The TF376 software module performs CA descrambling on the corresponding multiplexed frame and For safe broadcast information processing, the player can get the descrambled clear stream data from the TF376 software module and decode it. 
In this system, the demultiplexing and descrambling work are completed in the TD Baseband. The cleared stream after descrambling is sent to the TF376 software module for secure broadcast information processing, and the processed code stream is sent to the Decoder for decoding.