The Principle and Implementation of Digital TV Software and Hardware Separation

　　Preface:

　　At present, the software and hardware of the set-top box platform are closely integrated and inseparable. All software is integrated by the set-top box manufacturers. In order to cope with the various interfaces and applications of different operator customers, set-top box manufacturers have to pay a lot of software development costs, resulting in high set-top box prices.

　　The digital TV software and hardware separation set-top box platform is a very open digital TV application technology platform. On this hardware platform, third-party software companies can independently develop applications for operators to use. Even after the set-top box is distributed to users, new functional modules can be independently developed and downloaded to the set-top box for operation, without going through the integration test of the set-top box manufacturer. This breaks the closed software development model of traditional digital TV and reduces the software development pressure of the set-top box manufacturer. As time goes by, new functional modules can be easily added according to operational needs.

　　It is worth mentioning that this platform can easily support the development of any standard CA and the integration of any standard batch-used CA. CA library files do not need to be disseminated in large quantities, which can improve the security of smart card CA.

　　1. Necessity of separating digital TV software and hardware

　　The development of digital TV technology in the past was a very closed development model: chip manufacturers provided chips and software development environment to set-top box manufacturers, and then set-top box manufacturers developed applications on this platform. Any integration and modification of almost all third-party application software such as CA and data broadcasting requires the participation of set-top box manufacturers. It is difficult for other professional software developers to intervene, which limits the source and selection of software, greatly increases the software development pressure of set-top box manufacturers, and also creates a highly software and hardware bundled technology model. The more software such as CA and data broadcasting that set-top box manufacturers integrate, the more types of set-top boxes, and the more operator customers they face, the greater the pressure. In this case, the upgrade and improvement work will become very complicated. Set-top box manufacturers can only meet the software requirements before issuing translation set-top boxes. After batch use, even if problems are found, there is nothing they can do, let alone adding new functions.

　　After the separation of software and hardware, CA, data broadcasting, middleware and other application software can be independently developed by different software companies. These application software can be provided to operators separately. Each software can be replaced and upgraded independently. Set-top box manufacturers only produce bare machines with basic functions. Based on this set-top box software platform with separation of software and hardware, software development becomes a long-term process of improvement and function addition, unlike the early set-top boxes with bundled software and hardware, which are almost fixed for life after leaving the factory.

　　In the original software-hardware bundled model, the slow maturity of software restricted the upgrading of chips. The earliest set-top box chips that entered the market were widely used, but they were not the most advanced. After the separation of software and hardware, more chip manufacturers can participate in the competition, and cable TV operators can fully benefit from the rapid development of chip technology and use the latest chip technology to serve radio and television, instead of paying more to use set-top box chip products that are outdated three or even five years ago.

　　2. Selection of set-top box hardware platform

　　A set-top box is like a building, and the hardware platform is the foundation and frame of the building. Once formed, it cannot be replaced. The software is the decoration and residents in each room of the building. If the foundation is not good, the building cannot be built high, the grade is low, and naturally there are fewer people living in it. Just like the foundation of a building, the hardware of the set-top box determines the performance of the set-top box and the amount of functional expansion. Therefore, when operators and set-top box manufacturers focus on selecting a cost-effective set-top box hardware platform, they should first pay attention to the following points:

　　1. Use advanced semiconductor technology. For example, a chip using 90 nanometer technology has higher performance than a chip using 130 nanometer technology.

　　There is a lot of room for price reduction and the power consumption is also low.

　　2. The chip clock and processing speed are high enough, so that more applications requiring high processing speed can be expanded in the future.

　　3. Choose a set-top box chip that contains a more general CPU, such as the ARM series.

　　4. Considering security factors, you should choose set-top box chips from well-known international brands.

　　The following is a comparison of the performance of Sanyo LC74189 with ARM core and ST's STM5105:

　　From the above comparison, we can see that Sanyo's LC74189 has very obvious advantages. It has been tested in large-scale use, uses the most widely used ARM9CPU in embedded systems, and adopts advanced 90nm technology to directly integrate the QAM demodulator with the back-end decoding. Therefore, this design takes the software and hardware platform based on this set-top box chip as an example to introduce the principle and implementation of the set-top box software and hardware separation. At the same time, the chip also has the Great Wall cardless CA security management hardware module, and can also support any other standard CAS. [page]

　　3. Composition of the software platform

　　The software platform is the software part between the hardware application API, including operating system, hardware driver, MMU management, security management, vector management and application interface modules. It is a powerful open software platform that provides programmers with a rich software interface, allowing different software companies to develop various applications based on the platform, including the more important CA application. The framework of the entire software platform is as follows:

　　4. The role of software platform

　　The software platform after the separation of the hardware and software of the set-top box is between the hardware and the application. In a sense, it can also be called a kind of middleware, but it is different from the traditional middleware that people understand. Because it is necessary to realize functions such as CA and browser, so that some parts are closer to the hardware, it is also necessary to provide interfaces related to the hardware driver. For example, for the reception of DVB CA information, there are also functional interfaces such as serial port transmission and reception for troubleshooting. If this software platform must be understood as middleware, then it should be a middleware that is very close to the bottom layer. The software platform was commissioned by Japan's Sanyo Semiconductor Company to Shandong Taixin Electronics, combined with the actual application of Guangxi Radio and Television Network Company, to develop an open software platform interface standard. The purpose is to lower the technical threshold for set-top box software development and facilitate

　　Operators develop CA and other applications that involve their own interests by themselves, and take the initiative. Because each module can be improved independently, functional modules can be gradually added over time according to the needs of operations, which are difficult to think of when operators start to migrate. In this way, the functional modules that need to be added can be developed by different professional software companies selected by operators, and there is no need to find set-top box manufacturers to solve them. For example, after discovering the security problems of the CA used, it is easy to improve it, instead of being helpless as it is now.

　　It is worth mentioning that this structure allows the middleware developed by third-party software companies to be put into the set-top box as a separate module and can be replaced independently in the future. Operators do not have to worry about the upgrade of middleware in the future. On this platform with separated software and hardware, there are already modules such as browser-based and JAVA-based middleware, which further shields the hardware-related parts. Shandong Taixin helped Guangxi Radio and Television Network develop applications such as two-way data broadcasting, realizing VOD, karaoke, TV lottery, universal browser, stock broadcasting and other functions. These functions are no longer all integrated by set-top box manufacturers as before, but can be independently developed by different companies and used separately in set-top boxes. There are nearly ten companies participating in this development in Guangxi, and Shandong Taixin assists Guangxi Radio and Television in overall integration. If the separation of software and hardware is not achieved, this kind of collaboration is almost impossible.

　　5. Example of implementing CA on a software and hardware separation platform

　　CA is the most important part of the set-top box. In the past, the set-top box manufacturers used the library files provided by the CA manufacturers for integration. Not only was the integration test complex and time-consuming, but it was also an important reason for the proliferation of CW. However, by using the software and hardware separation technology based on LC74189, this integration can be completed independently by the CA manufacturer, without the need to provide any library files to each other, avoiding the time-consuming and laborious work of strengthening confidentiality and joint testing during the integration process, and can also largely avoid the occurrence of CW sharing, and operators can also get a cost-effective set-top box.

　　Because the development platform based on LC74189 has integrated all the basic functions required for designing CA, to develop CA based on the separation of software and hardware based on LC74189, you only need to do the following simple tasks:

　　1. Use the operating system interface provided by the system to create various threads and establish a running environment.

　　2. If it is a smart card CA, use the SMART card board driver provided by the system to develop the relevant functions of the SMART card. You can also directly apply the T0, T1 and other protocols provided by this system.

　　3. Use the DEMUX driver provided by the system to complete various meter collection actions.

　　4. Provide the interfaces required by the system, such as starting and stopping decoding, setting age levels, working hours, obtaining authorization information, etc., in order to complete the various functions of CA.

　　5. Compile on the software and hardware platform to generate an executable file, which is downloaded by the operator to the set-top box for execution without going through the set-top box manufacturer.

　　From the above work, it can be seen that not only is the work of transplantation much simpler than traditional integration, but the key is that the integration environment is very independent. CA and other set-top box software can be independently completed and tested by different companies. The integration of CA can be completely handed over to CA manufacturers or operators to complete independently, and downloaded to the set-top box through the operator's front-end download server for execution, and the original smart card can also be used.

　　Since a high-level interface for developing CA is provided, it is very convenient to develop a new CA or transplant an existing CA. Since even the most complex CA application can be developed on the basis of software and hardware separation, other applications, such as stocks, browsers, interfaces, etc., are easier to implement on the software and hardware separation platform.

　　Now, the test version of this LC74189-based software-hardware separation development platform can be downloaded free of charge from the Shandong Taixin Electronics Company website: www.taixin.cn/bbs.

　　6. The significance of realizing software and hardware separation

　　The separation of digital TV software and hardware fundamentally breaks the old model of software and hardware bundling that has long imprisoned the healthy development of radio and television. It allows software development to be continuously improved and new functional modules to be added as operational needs change, rather than just limiting the business to a network with almost fixed functions. It will also greatly reduce the cost of translation, which is also the wish of many radio and television stations.

　　In the post-conversion era, many radio and television companies have made profound summaries of the networks that have already been migrated. How to operate them is a topic of common concern among radio and television people.

　　Operators who have not yet made the switch can learn from the experience and lessons of the pioneers. It should be said that the bundled software and hardware of the set-top box cannot independently improve and upgrade each software, making it more difficult to add new applications, which has compressed the space for operators to carry out value-added applications. This is the biggest lesson learned by operators who have already made the switch. In addition, CA is unable to take technical measures to remedy security risks after discovering them, which makes operators feel insecure, which is another major problem after bundling software and hardware. These lessons are worth learning for operators who have not yet made the switch to avoid making the same detour again.