As the process of digital television transition deepens, the focus of the overall conversion has shifted from urban areas to towns and villages. According to the requirements of the National Radio and Television Administration's "12th Five-Year Plan," by 2015, cable networks in cities at the county level and above must fully achieve digitization, with 80% realizing two-way communication, gradually shutting down analog channels, and adding 100 million two-way digital television users.
However, the current market for county-level transitions is mixed, with a large number of low-priced, low-quality, and low-technology products flooding the market. This not only leads to a dilemma for county-level network operators due to product quality and service issues but also creates countless obstacles for future provincial network integration, severely affecting the public perception of the digital television transition, which is a project that resonates with the people.
Based on years of experience in digital television transition, Onebandinp has tailored a low-cost, high-quality, end-to-end two-way digital television transition solution for county-level network operators, laying a solid foundation for future provincial network integration and contributing to the National Radio and Television Administration's digital transition project in towns and villages.
To better ensure the safety and stability of system operation, this system adopts a fully Harrier front-end design, which facilitates unified management of the system by users and simplifies system upgrades and expansions.
II. Solution Details
This solution employs fully Harrier equipment for signal reception, encoding, multiplexing, scrambling, and modulation. Depending on the different payment platforms accessed by users, the system is designed to output a minimum of 100 standard definition channels to users, making it economical and practical. Additionally, users can flexibly implement functions such as hot/cold backup of equipment, seamless expansion, and smooth upgrades according to their needs. Furthermore, due to the development of high-definition programming, we also provide an expansion solution for high-definition channels based on the design of this front-end. Below are the detailed contents of the solution:
2.3.1 Signal Source Processing
The front-end system design utilizes 12 Harrier ProView7000 receivers for satellite signal reception, with each receiver equipped with four QPSK RF input boards, allowing reception of four satellite frequency points. It provides main and backup IP output ports, enabling the output IP signals to be simultaneously sent to main and backup switches for redundancy. Each receiver is configured with 2 CI slots for program descrambling and has 4 ASI input ports that can convert incoming ASI signals to IP format output.
User-operated programs are encoded using the Harrier Ion encoder, which can provide single, dual, or quad encoding configurations. Users can flexibly choose the number of Ion encoding channels based on their actual situation to save costs. The Ion encoder also features main and backup IP output ports for signal source redundancy.
2.3.2 Core Switch
The system adopts the currently most popular all-IP front-end architecture, characterized by a simple and clear structure, with high security and stability. The core switch utilizes Cisco's 3750 series Gigabit switches, which are standardized and regulated, facilitating daily maintenance and management for users. Additionally, the switches operate securely and stably, fully meeting the safety requirements for front-end broadcasting.
2.3.3 Program Multiplexing and Scrambling
The program multiplexing and scrambling utilize Harmonic's flagship product, the Prostream1000 multiplexer. Each Prostream1000 can be flexibly configured with 5 input/output cards (ASI or GBE). Based on the actual conditions of the front-end applications that have completed digital transformation, we provide a configuration of 1 GBE card and 1 ASI card in this solution. The IP input signals provided by the receiving and encoding section are input/multiplexed and scrambled through the GBE card.
The reason for configuring the ASI card is that the central 35689 sets of programs in various regions currently use dedicated receivers and decryption cards. During the analog-to-digital transformation, it is necessary to provide program sources for both analog and digital transmission systems. Configuring the ASI card allows the ASI signals output from the existing dedicated receivers to be input into the multiplexer for multiplexing and scrambling operations without the need to add extra receivers or decryption cards. This also facilitates users in integrating advertisement insertion systems (some advertisement systems require ASI interfaces for input to the multiplexer).
The Prostream1000 features flexible card configurations; this system is equipped with 2 input/output cards, and users can purchase additional ASI or GBE cards as needed (for example, in the case of downstream programs, some regions' downstream programs are in multiple ASI formats, allowing users to order the corresponding number of ASI cards based on the stream count).
The Prostream1000 has independent scrambling ports and supports single and shared encryption from various domestic and international CA vendors.
In this system, the Prostream1000 connects to the core switch via the primary GBE port of the GBE card, selects IP streams from the core switch, and then outputs the processed streams from the original port after multiplexing and scrambling. The GBE card also has primary and backup GBE ports, allowing simultaneous connections to primary and backup switches for redundancy.
While outputting the scrambled streams, the Prostream1000 can also mirror the clear streams for monitoring purposes. The mirrored streams are directly output to the core switch, from which the video monitoring system can extract the required programs.
2.3.4 Program Modulation Output
The output stream from the multiplexer is in IP format. This solution employs Harmonic's broadcast-grade high-density IPQAM modulator BNSG9000, which can accommodate 9 QAM output modules. Each module contains two output ports, and each port includes up to 3 output channels for adjacent RF frequency points.
In this solution, the BNSG9000 receives digital streams from the core switch via the GBE port and outputs them through the QAM RF port.
The BNSG9000 offers card backup functionality, allowing network management to seamlessly switch to a backup card in the event of a failure of a primary card. It also features dual power supply configuration to ensure the safety of program broadcasting.
The BNSG9000 provides an ASI stream monitoring port, allowing any RF output stream to be sent to the monitoring output. This enables the use of a stream analyzer to monitor the internal transmission flow of the system, facilitating fault detection.
All RF modules and power modules are designed for hot-swapping, allowing for smooth upgrades to the system without interrupting service.
3. System Expansion Plan (Optional)
3.1 Backup Plan
This solution utilizes the NMX Digital Business Management System for integrated management, allowing for multi-level backups. In addition to the cold backup at the front-end receiver, all other levels are hot backups. The advantage of hot backups lies in their fully automated parameter or equipment switching, resulting in minimal program interruption time, making it suitable for users with high security requirements. Multi-level backups ensure the security of program transmission, and below is a detailed introduction to multi-level hot backups.
- Input stream hot backup
The ProView7000 features primary and backup IP output ports, allowing for the additional configuration of a core switch for input stream backup. The GBE card of Prostream has primary and backup ports that can be connected to the primary and backup switches, respectively. When a stream failure occurs on the primary switch, the NMX network management system will directly control the Prostream to receive the stream from the backup switch, with program interruption time controllable to around 1 second.
Core Equipment Hot Backup
The core devices of the system (Prostream1000 and BNSG9000) can perform 1+1 or N+1 hot backup under the control of the NMX network management system. When the primary device is functioning normally, the backup device remains idle and unconfigured; when a major fault occurs in the primary device (such as a crash, power failure, or other issues affecting normal program transmission, with users able to configure the types of faults for switching), the NMX network management will push the parameters from the primary device to the backup device, activate it, and disable the primary device. After the switch is completed, users can wait for the primary device to be debugged and functioning normally before manually switching the parameters back to the primary device. During program switching, the automatic switch time for faults is within 3 seconds, while the manual switch back to the primary device takes less than 1 second.
Backup of Modulator Cards
The BNSG9000 modulator can perform card backup. In this solution, the designed program list can transmit using 20 RF frequency points, requiring the configuration of 4 modulator cards. Users can choose to equip RF cards for backup; when an issue occurs with one of the primary cards, the backup card can replace the primary card for output. Since the BNSG can be configured for card backup, users do not need to back up the BNSG device, saving costs.
Individual Program Backup
The Prostream1000 can back up certain programs, allowing users to set backup functions for important or easily interrupted programs. When the designated program is interrupted, the pre-set backup program can directly replace it for output without needing to change the program PID, scrambling, or other information, with a program switch time of less than 1 second.
The above backup functions require users to purchase additional hardware cards or devices.
3.2 High-Definition Landing Transcoding Solution
With the development of high-definition digital television, some users require the expansion of receiving and transmitting high-definition programs based on the existing front-end system. As the number of cable digital television programs increases, the frequency point resources of cable networks are becoming increasingly scarce, and traditional MPEG-2 encoded high-definition programs require a large amount of bandwidth resources. Therefore, it is also necessary to convert MPEG-2 encoded high-definition programs into low-bandwidth H.264 encoded high-definition programs to reduce the occupation of frequency point resources.
Based on the existing system, we propose to configure the ACE transcoding card for the Prostream1000. Each transcoding card can achieve the transcoding of 5 sets of high-definition programs from MPEG-2 to H.264, reducing the bitrate of a single high-definition program from the original 16-18M to 6-8M. This allows each frequency point, which originally transmitted 1-2 sets of high-definition programs, to now transmit 4-5 sets of high-definition programs, thus saving frequency point resources.
This expansion solution requires users to purchase additional ACE transcoding cards.
For equipment pricing and detailed specifications, please consult the Technical Department or Marketing Department of Onebandxin at 010 65302100.support@onebandsys.com ；info@onebandsys.com