ADSL CPE with Virata Helium and ST chips
ã€Abstract】 The functions and implementation of Virata Helium and ST chipsets are discussed in detail from the perspective of theoretical and practical development.
Keywords: access network, asymmetric digital subscriber loop, integrated services, digital network 1 Introduction In the network era, various services on the Internet are developing rapidly. The original narrow-band data access form mostly uses 56K dial-up Internet access, DDN and X. Mainly 25, which has severely restricted the demand for actual data network applications and limited the further development of the entire data network business. In order to realize the digitization and broadbandization of the user access network and increase the user's Internet access speed, fiber to the home will be developed in the future. However, due to the high cost of optical fiber user networks, most user networks will continue to use the existing copper wire loops in the next decade or even decades, so in recent years, people have proposed a number of transitional broadband access Network technology, including N-ISDN, Cable Modem, ADSL, etc. Among them, ADSL technology is a new access technology that provides broadband services to homes and small companies using existing copper twisted-pair telephone subscriber lines. It makes full use of the twisted-pair subscriber lines of the existing telephone network, which is conducive to transformation and conforms to China's current national conditions, and has become a preferred solution in the construction of access networks.
Huasheng Group is a company with nearly two decades of history, dedicated to network communications and audiovisual distribution. Up to now, Huasheng PCI ADSL MODEM, USB ADSL MODEM, ADSL MODEM with Ethernet interface and ADSL ROUTER with routing function have been launched in four categories and six series of products. The WS-2x01 series ADSL MODEM produced by the company uses the kit combination produced by Virata Helium STMicroelectronics. The main goal of this solution is to realize the CPEADSL reference design. WS-2x01 provides full rate (ANSI and G. DMT) and G. Lite support, connected to a PC via an Ethernet interface (RJ45) or USB, can provide asymmetric transmission of 640kbps upstream and 8Mbps downstream.
2 Introduction to ADSL system In the process of developing ADSL MODEM, we selected Helium (as main processor and interface) of Virata company and ASCOT chip of STMicroelectronics company.
Helium produced by Virata is composed of protocol processor, network processor, Utopia and peripheral bus interface. The protocol processor and the network processor core are ARM7TDMI RISC (Reduced InstrucTIon SetComputer). Protocol processors are used for general processing, where high-level protocols are run. The network processor is used for the processing of cells, frames and packets. Helium can run a complete set of ATMOS (ATMOperaTIon System) software, including bridge, routing, SNMP (Simple Network Management Protocol) management, UNI (User Network Interface) signaling, NDIS (Network Driver Interface Standard), etc. Helium is a powerful controller that connects ATM physical layer devices, such as ATM25 or xDSL, to other interfaces such as Ethernet or USB, and provides various hardware interfaces with 32-bit processors for high-level protocol processing. The MODEM hardware is also based on ASCOT's set of chips: ST70134 is an analog front end, and ST70135A is a DMT (Discrete MulTI-tone) engine. ST70134 provides some additional filtering, analog-to-digital conversion and VCXO control (for central clock recovery). ST70135A is a DMT engine that performs FFT (Fast Fourier Transform), IFFT (Inverted Fast Fourier Transform) transformation, quantization in time and frequency domains, reed salomon and trellis coding. ST70135A is connected to Helium via Utopia bus and peripheral bus.
The composition of the entire ADSL MODEM system is shown in Figure 1.
3 Comparison of various MODEMs The four ADSL MODEM products currently occupied by Zhuhai Huasheng Company are: WS-2301, WS-2601, WS-2801 and WS-2901. These ADSL MODEMs complete the DMT modulation and demodulation functions on the one hand through AFE (Analog Front End), DSP (Digital Signal Processing), UTOPIA interface and other modules, on the other hand, they provide the DTE (Data Terminal Equipment) interface, so that user equipment can access the broadband network through high-speed data channels. Since the world's well-known chip manufacturers all have their own DMT-based modem chips, in order to make the user terminal and the central office interconnected, the user terminal manufacturers adopt the product strategy of supporting each one according to the central office equipment. Alcatel Office The terminal occupies more than 40 shares in the market, so the chipset compatible with it is generally selected in hardware.
In terms of software development, according to different host control interfaces, there will be different control methods. PCI / USB occupies PC resources and operating system for upper layer protocol processing and system configuration. The ADSL MODEM of the built-in RISC CPU needs to complete the software program of the relevant communication protocol according to different CPUs in addition to the operating system. Figure 2 is the software composition.
The following four ADSL MODEM physical layers also support ANSI TI. 413 Issue2, ITU-TG. 992.1 (G. DMT) and G. DMT. 992.2 (G. Lite), and supports UNI3.0 and 3.1 signaling.
(1) PCI ADSL MODEM (WSï¼2301)
This ADSL MODEM is a built-in card, connected to a PC via a PCI bus. Its characteristics are: small size, software is in the PC, and the development environment is better, but it takes up more processing resources of the PC and is prone to hardware DMA and I / O conflicts. For telecom operators, it is not easy to maintain. This card does not have any special requirements for the operating system. Windows 95, 98, NT4.0, and 2000 can be used. The protocols it supports are RFC1577-Classical IPOver ATM, RFC1483-Bridged Ethernet Over ATM PVCs, and RFC2364-PPPOver ATM PVCs.
(2) USB ADSL MODEM (WS-2601)
This ADSL MODEM is connected through the USB interface that comes with the user's PC. It does not need to open the case, no external power supply is required, and it occupies less PC resources. In addition to supporting the protocols supported by the above PCI ADSL MODEM, it also supports PPP Over Ethernet. , And configurable PAP (Password Authentication Protocol) / CHAP (Chanllenge Handshake Authentication Protocol) authentication. The characteristic of this external MODEM is that the development environment requires higher (on the communication processor) and the price is more expensive.
(3) ADSL MODEM with Ethernet interface (WS-2801)
This ADSL MODEM only requires the user to have an ordinary network card, which is connected to the PC through an Ethernet interface (RJ45). It can also support PPP Over Ethernet and can also be configured with PAP / CHAP authentication. This MODEM is the leading product in the current broadband access market, and its disadvantage is that the user end must install a driver.
(4) ADSL MODEM with routing function (WS-2901)
This ADSL MODEM is also connected to the user's PC through the RJ45 port of the network card. In addition to supporting all the above protocols, it also has routing functions. It can implement DHCP (Dynamic Host C Protocol), DNS (Domain Name Server), and NAT. (Net Address Translation), and packet filtering and other functions. The disadvantage is the high price.
4 G in the future evolution ADSL MODEM. Lite is expected to become a standard peripheral due to its low cost, easy installation, plug-and-play, low power consumption, and 5 times the speed of a 56K Modem, thus replacing the widely-used modem and becoming a powerful tool for users to access the Internet.
Judging from the current development of ADSL, ADSL broadband access has not only been used as a pure access technology, its application in high-speed data network access has more vitality. Many experts in the industry firmly believe that xDSL technology based on ADSL will eventually become a winner on copper twisted pair lines. VoDS will be one of the solutions that use DSL lines to provide multiple packet voice lines at the same time in the next few years. One of the markets.
VoDSL refers to the transmission of packet voice over DSL lines. Currently, VoDSL can carry up to 24 packet voice links on a DSL line. VoDSL technology was rated as one of the “Top Ten Hotspot Technologies†in 2000, and it has also been referred to as the technology of turning copper into gold by some companies. As the products mature, the VoDSL business will develop rapidly in the next 4 to 5 years, and different operating companies will enter the VoDSL market in different ways. Some long-distance companies will use it as a means to enter the local market. Large operating companies see it as an application that promotes broadband access. The most important thing is to provide multiple telephone lines with low prices for SMEs. According to CIR predictions, there will be 25 million VoDSL lines worldwide by 2005, of which one-third will be in North America. VoDSL technology is not just a new transmission technology, it will become the main technology of the new generation of voice services for small and medium-sized enterprises. In the next few years, VoDSL will become a standard feature of DSL equipment, and voice is becoming the new killer application of DSL services.
2 Charles K. Summers. ADSL Standard, Implementation and Architecture. CRC Press, 1999
3 Albert Azzam, Niel Ransom. Broadband Access Technï¼ologies. McGraw Hill Compaines, Inc., 1999
4 Technical Report DSL Forum TR-032. CPE Architecture Recommendations for Access to Legacy Data Networks. 2000, 5
Keywords: access network, asymmetric digital subscriber loop, integrated services, digital network 1 Introduction In the network era, various services on the Internet are developing rapidly. The original narrow-band data access form mostly uses 56K dial-up Internet access, DDN and X. Mainly 25, which has severely restricted the demand for actual data network applications and limited the further development of the entire data network business. In order to realize the digitization and broadbandization of the user access network and increase the user's Internet access speed, fiber to the home will be developed in the future. However, due to the high cost of optical fiber user networks, most user networks will continue to use the existing copper wire loops in the next decade or even decades, so in recent years, people have proposed a number of transitional broadband access Network technology, including N-ISDN, Cable Modem, ADSL, etc. Among them, ADSL technology is a new access technology that provides broadband services to homes and small companies using existing copper twisted-pair telephone subscriber lines. It makes full use of the twisted-pair subscriber lines of the existing telephone network, which is conducive to transformation and conforms to China's current national conditions, and has become a preferred solution in the construction of access networks.
Huasheng Group is a company with nearly two decades of history, dedicated to network communications and audiovisual distribution. Up to now, Huasheng PCI ADSL MODEM, USB ADSL MODEM, ADSL MODEM with Ethernet interface and ADSL ROUTER with routing function have been launched in four categories and six series of products. The WS-2x01 series ADSL MODEM produced by the company uses the kit combination produced by Virata Helium STMicroelectronics. The main goal of this solution is to realize the CPEADSL reference design. WS-2x01 provides full rate (ANSI and G. DMT) and G. Lite support, connected to a PC via an Ethernet interface (RJ45) or USB, can provide asymmetric transmission of 640kbps upstream and 8Mbps downstream.
2 Introduction to ADSL system In the process of developing ADSL MODEM, we selected Helium (as main processor and interface) of Virata company and ASCOT chip of STMicroelectronics company.
Helium produced by Virata is composed of protocol processor, network processor, Utopia and peripheral bus interface. The protocol processor and the network processor core are ARM7TDMI RISC (Reduced InstrucTIon SetComputer). Protocol processors are used for general processing, where high-level protocols are run. The network processor is used for the processing of cells, frames and packets. Helium can run a complete set of ATMOS (ATMOperaTIon System) software, including bridge, routing, SNMP (Simple Network Management Protocol) management, UNI (User Network Interface) signaling, NDIS (Network Driver Interface Standard), etc. Helium is a powerful controller that connects ATM physical layer devices, such as ATM25 or xDSL, to other interfaces such as Ethernet or USB, and provides various hardware interfaces with 32-bit processors for high-level protocol processing. The MODEM hardware is also based on ASCOT's set of chips: ST70134 is an analog front end, and ST70135A is a DMT (Discrete MulTI-tone) engine. ST70134 provides some additional filtering, analog-to-digital conversion and VCXO control (for central clock recovery). ST70135A is a DMT engine that performs FFT (Fast Fourier Transform), IFFT (Inverted Fast Fourier Transform) transformation, quantization in time and frequency domains, reed salomon and trellis coding. ST70135A is connected to Helium via Utopia bus and peripheral bus.
The composition of the entire ADSL MODEM system is shown in Figure 1.
3 Comparison of various MODEMs The four ADSL MODEM products currently occupied by Zhuhai Huasheng Company are: WS-2301, WS-2601, WS-2801 and WS-2901. These ADSL MODEMs complete the DMT modulation and demodulation functions on the one hand through AFE (Analog Front End), DSP (Digital Signal Processing), UTOPIA interface and other modules, on the other hand, they provide the DTE (Data Terminal Equipment) interface, so that user equipment can access the broadband network through high-speed data channels. Since the world's well-known chip manufacturers all have their own DMT-based modem chips, in order to make the user terminal and the central office interconnected, the user terminal manufacturers adopt the product strategy of supporting each one according to the central office equipment. Alcatel Office The terminal occupies more than 40 shares in the market, so the chipset compatible with it is generally selected in hardware.
In terms of software development, according to different host control interfaces, there will be different control methods. PCI / USB occupies PC resources and operating system for upper layer protocol processing and system configuration. The ADSL MODEM of the built-in RISC CPU needs to complete the software program of the relevant communication protocol according to different CPUs in addition to the operating system. Figure 2 is the software composition.
The following four ADSL MODEM physical layers also support ANSI TI. 413 Issue2, ITU-TG. 992.1 (G. DMT) and G. DMT. 992.2 (G. Lite), and supports UNI3.0 and 3.1 signaling.
(1) PCI ADSL MODEM (WSï¼2301)
This ADSL MODEM is a built-in card, connected to a PC via a PCI bus. Its characteristics are: small size, software is in the PC, and the development environment is better, but it takes up more processing resources of the PC and is prone to hardware DMA and I / O conflicts. For telecom operators, it is not easy to maintain. This card does not have any special requirements for the operating system. Windows 95, 98, NT4.0, and 2000 can be used. The protocols it supports are RFC1577-Classical IPOver ATM, RFC1483-Bridged Ethernet Over ATM PVCs, and RFC2364-PPPOver ATM PVCs.
(2) USB ADSL MODEM (WS-2601)
This ADSL MODEM is connected through the USB interface that comes with the user's PC. It does not need to open the case, no external power supply is required, and it occupies less PC resources. In addition to supporting the protocols supported by the above PCI ADSL MODEM, it also supports PPP Over Ethernet. , And configurable PAP (Password Authentication Protocol) / CHAP (Chanllenge Handshake Authentication Protocol) authentication. The characteristic of this external MODEM is that the development environment requires higher (on the communication processor) and the price is more expensive.
(3) ADSL MODEM with Ethernet interface (WS-2801)
This ADSL MODEM only requires the user to have an ordinary network card, which is connected to the PC through an Ethernet interface (RJ45). It can also support PPP Over Ethernet and can also be configured with PAP / CHAP authentication. This MODEM is the leading product in the current broadband access market, and its disadvantage is that the user end must install a driver.
(4) ADSL MODEM with routing function (WS-2901)
This ADSL MODEM is also connected to the user's PC through the RJ45 port of the network card. In addition to supporting all the above protocols, it also has routing functions. It can implement DHCP (Dynamic Host C Protocol), DNS (Domain Name Server), and NAT. (Net Address Translation), and packet filtering and other functions. The disadvantage is the high price.
4 G in the future evolution ADSL MODEM. Lite is expected to become a standard peripheral due to its low cost, easy installation, plug-and-play, low power consumption, and 5 times the speed of a 56K Modem, thus replacing the widely-used modem and becoming a powerful tool for users to access the Internet.
Judging from the current development of ADSL, ADSL broadband access has not only been used as a pure access technology, its application in high-speed data network access has more vitality. Many experts in the industry firmly believe that xDSL technology based on ADSL will eventually become a winner on copper twisted pair lines. VoDS will be one of the solutions that use DSL lines to provide multiple packet voice lines at the same time in the next few years. One of the markets.
VoDSL refers to the transmission of packet voice over DSL lines. Currently, VoDSL can carry up to 24 packet voice links on a DSL line. VoDSL technology was rated as one of the “Top Ten Hotspot Technologies†in 2000, and it has also been referred to as the technology of turning copper into gold by some companies. As the products mature, the VoDSL business will develop rapidly in the next 4 to 5 years, and different operating companies will enter the VoDSL market in different ways. Some long-distance companies will use it as a means to enter the local market. Large operating companies see it as an application that promotes broadband access. The most important thing is to provide multiple telephone lines with low prices for SMEs. According to CIR predictions, there will be 25 million VoDSL lines worldwide by 2005, of which one-third will be in North America. VoDSL technology is not just a new transmission technology, it will become the main technology of the new generation of voice services for small and medium-sized enterprises. In the next few years, VoDSL will become a standard feature of DSL equipment, and voice is becoming the new killer application of DSL services.
references
1 Warrier, P. , Kumar, B. Edited. XDSL architecture. Beijing: Tsinghua University Press, 2000, 11 2 Charles K. Summers. ADSL Standard, Implementation and Architecture. CRC Press, 1999
3 Albert Azzam, Niel Ransom. Broadband Access Technï¼ologies. McGraw Hill Compaines, Inc., 1999
4 Technical Report DSL Forum TR-032. CPE Architecture Recommendations for Access to Legacy Data Networks. 2000, 5
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