NEXT GENERATION DIGITAL CABLE BROADBAND ACCESS PRODUCTS. STMicroelectronics Ltd., Plot no. 2&3, Sector-16A, Noida (U.P.)

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1 NEXT GENERATION DIGITAL CABLE BROADBAND ACCESS PRODUCTS Dr.P.C.Jain STMicroelectronics Ltd., Plot no. 2&3, Sector-16A, Noida (U.P.) ABSTRACT The combination of best-of-class RF and digital integrated circuits enables cable modem and set-top box products that deliver high performance, integration, and enhanced services at aggressive new price points that will enable worldwide manufacturers of cable access products to gain significant time-to-market, competitive and price/performance advantages. Cable broadband offers significant opportunities for cable OEM s and cable operators, and it paves the way for new classes of services for consumers, ranging from high speed Internet access to Video-on-Demand and future home networking. Cable access products begins to migrate to converged video, voice, and Internet cable capabilities. I. INTRODUCTION The telecom. resolution has given rise to a new generation of cable operators on a mission to change the competitive dynamics of the industry. Cable operators are already the preeminent providers of video services, but not content. To adopt the business as usual model of the past, next generation cable operators have embarked on an aggressive program of network conversion and upgrades to meet the growing needs of service-hungry consumers. With the cable modem services already leading broadband data communications to the home, the cable industry is ahead in the convergence of voice, video and data services. Adding voice to cable s existing mix of video and data services provides cable operators with a competitive advantage. The work already undertaken to provide interactive and data services, such as twoway plant upgrades and data over cable services interface specs. (DOCSIS) networking standards, has paved the way for cable operators to provide telephony services. With the physical infrastructure to provide high quality voice services in place, the cable industry has all the elements of a convergent network capable of delivering an entire suite of voice, video and data services. These capabilities are embodied in the next generation network. A next generation network comprises two fundamental characteristics: a high speed packet or cell based network capable of transporting and routing a multitude of services, including voice, data and video; and a common platform to deliver new applications and enhanced services. This type of network is a formula for profit for cable operators. By using a simple piece of customer premises equipment (CPE), next generation cable operators can achieve significant reduction in capital costs as they utilize advanced packet technologies for voice services while offering new, revenue-generating services over a single network. These operators no longer have to wait for their switch vendor to deliver a proprietary software upgrade. Rather, by leveraging open standards and promoting open application program interface (API), operators have a system with a highly flexible environment to support rapid development of new services. II. CABLE ACCESS SYSTEM Cable network was originally meant for the delivery of broadcast analog TV services. By using MPEG compression in conjunction with advanced modulation and coding techniques, cable TV network could, without any modifications, also support one-

2 way broadcast digital services. The signalto-noise ratio required to support high quality analog video over the cable network are more than sufficient to support advanced digital modulation techniques such as 64- and 256-QAM. While first generation digital cable TV services have been deployed over one way networks, there is an enormous demand for advanced two-way services over cable networks such as Internet access data services, interactive TV video services with integrated web content, and voice and video telephony services. As a result cable operators have to make major investments to upgrade their networks to achieve two-way capability. These so called hybrid fibercoax. (HFC) network consist of fiber optic cables in the backbone and coaxial cable connections to the subscribers which have been upgraded with diplex filter and bidirectional amplifiers to handle two-way traffic. A typical HFC plant uses the 5-42MHz band upstream traffic and the MHz band for downstream traffic. II-A Cable Modem Cable modems are emerging as the dominant broadband Internet access platform within the home. They offer downstream speeds up to 52Mb/s and upstream up to 10Mb/s. These speeds easily support high quality full motion video, which will unleash a wide variety of new residential services such as video conferencing and video telephony. Cable operators will also be providing conventional phone service as well over cable modem. Unlike telephone line modem connections, which are point-to-point links, cable modems operate on a shared medium in a point-to-multipoint configuration. In the downstream direction the cable head-end broadcasts a continuous bit stream to all subscribers. Each user is assigned unique address and time division multiplexing (TDM) is used to share the single downstream data channel among the various users. The upstream uses a time division multiple access (TDMA) protocol whereby users send requests for data transmission to the head-end and are then assigned specific time slots to send data in short bursts. When a user has no data to send, its transmitter is turned off which frees up the channel for other users. The head-end media access controller (MAC) arbitrates among all the data requests and manages the BW allocations to the individual users. Since cable modem operate on a shared medium, the data encryption standard (DES) is now being offered as a standard feature in cable modems to ensure privacy of data. Furthermore, as network congestion increases with the addition of new subscribers, additional RF carriers can be allocated in both the upstream and downstream directions, thereby segmenting the network into smaller and smaller groups of users. This combined frequency division and time division multiple access scheme (FDMA/TDMA) results in an efficient protocol for managing the data rate loading of the network. Another advantage of the TDMA protocol is the Always ON feature of the cable modems. Once a connection has been established upon power up of the modem, there is no need even to turn it off. Network resources are not being used if no data is being transmitted. This is not the case with telephone modems, which tie up the phone line even if no data is being communicated. One of the most important considerations for successful widespread deployment of data communications services is standardization of transmission protocols to achieve interoperability among multiple vendors. This has been achieved with cable modem through the adoption of the multimedia cable network system/data over cable services interface specs. (MCNS/DOCSIS). The net result of the standard is that cable modems will now be made available in retail outlets and cable ready PCs; with built-in cable modems will now begin to be offered as standard configurations. A cable modem (CM) has two parts, one connected to PC and other to home network. The CM communicates over the cable network to a device cable modem termination system (CMTS) which is central

3 device for connecting the cable TV network to a data network at cable operator head-end. The tuner in CM receives a digital signal from the cable network and isolates a particular channel that contains the Internet data. It then converts the signal from RF level back to base band. The base band output signal from the tuner is then forwarded to a digital demodulator. The demodulator samples the signal and converts it to a digital bit stream. The bit stream contains video, audio and Internet data. Once the bit stream is recovered it is forwarded to a forward error correction (FEC) decoder for bit error correction. The signal is then passed into the control unit and further to the network using one of the high speed data port interfaces. STMicroelectronics developed a compressive DOCSIS 1.1 compliant cable modem reference design based on STV0396 single chip cable modem and Microtune s single chip tuner MT2040 and amplifier chips. The reference design offers the most cost effective cable modem system in the market. It is ready to evaluate, customize and produce solution accelerating the deployment of DOCSIS1.1 based cable access devices. STV0396 chip targets cable data modems, voice and video over Internet Protocol (IP) gateways and advanced interactive set-top box (STB). It integrates a DOCSIS1.1 compliant physical layer (PHY) supporting both upstream and downstream functions, a DOCSIS 1.0/1.1 MAC, a powerful 32-bit system micro-controller with integrated instruction and data caches, 8kbytes of embedded SRAM and a rich set of peripherals and integrated interface modules for most popular cable modem to CPE connections. The combination of integration level and performance makes the STV0396 single chip modem the most cost effective solution on the market, making it a key component in accelerating the rapid expansion of the market for broadband applications over HFC networks. On board USB, Ethernet and PCI connectors will enable cable modem manufacturers to rapidly build final product variants using the evaluation board. II-B. Cable Internet Set-Top-Box Cable Internet STB offers TV reception, web surfing, advanced display and graphics features and video streaming. A cable Internet STB needs a RF tuner, a downstream QAM demodulator, an upstream QAM/QPSK transmitter, an MPEG video/audio decoder, graphics display processor, and a 32-bit RISC processor and memory. Reference design deploys ST s STV0297J QAM demodulator, STi5514 single chip STB decoder, ST40GX1 graphics chip and STV0396 single chip cable modem implemented with Microtune tuner and amplifiers chips. The reference design offers a feature-rich massmarket cable STB solution at aggressive new price points. There is a significant opportunity for OEM s in the cable broadband market, but they need complete solutions that offer superior performance and low price points in order to gain a competitive edge. This cable STB can deliver new classes of service worldwide, ranging from high speed Internet access to video-on-demand (VoD) and home networking. II-C. Voice-Over-Internet Telephony Voice-over-Internet Protocol (VoIP) processor incorporates a fast highly parallel digital signal processing engine, the VP7-A designed for Internet protocol telephony applications by Netergy Microelectronics, a high performance memory subsystem, a TDM module and an external host processor bus interface. The VP7-A is an eight-way single-instruction multiple data path (SIMD) architecture optimized for parallel computeintensive sections of audio processing algorithms. The VP7-A combines a four parallel high precision multiply accumulate unit (MAU) with a four-parallel fullfunction arithmetic Logic Unit (ALU) and a separate RISC processor, all of which can operate concurrently, It enables multiple, parallel audio channels to be processed with little overhead from the external host

4 processor with direct support for 8/16 bit audio and telecom codecs, the TDM interface is compatible with the vast majority of the industry standard telecom bus formats and external codec interfaces, supporting both 8 and 16 bit audio and telecom codecs. The TDM supports 32 bidirectional streams with arbitrary mapping of the 128 time slot to input/output streams, with a maximum bit rate of Mb/s (programmable). Each stream uses a DMA managed double buffering scheme, requiring minimal external host processor support. The ST s STV0397 is a member of a family of highly integrated, multi-channel VoIP processor for cable network based telephony products. The VoIP processor in conjunction with the STV0396 MCNS/DOCSIS single chip cable modem and VoIP firmware, enables designers to develop low cost, Packet cable compliant voice solutions for the cable market. At the heart of the STV0397 is the STMicroelectronics high performance STBus interconnect technology with 800Mbytes of internal data BW, 8kbytes of high speed internal SRAM for local data buffers, and a programmable external memory interface module (EMI) containing a zero glue logic SDRAM controller, thus helping to keep the system cost to a minimum. The STV0397 incorporates an external host processor interface which supports a 33/66MHz 32 bit PCI v2.1 interface which enables this device to be used in many PCI based systems, including PC and STB applications The multimedia terminal adaptor (MTA) and network interface unit (NIU) designs that incorporate the VoIP processor are capable of transforming analog voice and control signals into IP packets and communicating with servers using NCS1.0 compliant MGCP. The VoIP processor provides a host processor interface (PCI) to an external processor, which serves as a controller supervising data and program flow to the VoIP processor. In a typical voice application, the host processor executes the call protocols, network interface, MAC and other system functions, while the VoIP processor independently executes multiple channels of audio compression/decompression processing functions and fetches instructions and data from memory. The VoIP software includes the calling/signaling protocol stack that run on the host processor while the audio library that runs on the VoIP processor. The protocol stack supports H.323v2, MGCP/Megaco and SIP protocols. The audio library includes a complete range of ITU Vocoders and all of the audio models necessary to build complete VoIP terminal or gateway, including G.711, G.722, G.723.1, G726, G728, G729A/B and G.729E, acoustic and line echo cancellation (G.165 and G.168) with adjustable echo buffer length, automatic gain control, comfort noise generation, voice activity detection, silence suppression, FAX/ modem tone detection and dual tone multi-frequency (DTMF) generation and detection. III. MARKET POTENTIAL Cable modem services are absolutely hot, according to In-Stat group. The high-tech market research firm reports that total worldwide cable modem subscribers are expected to hit 34 million by the end of By 2007, In-Stat projects that there will be 68 million worldwide cable modem subscribers. With the demand for high speed Internet access increasing, many of the world s leading cable TV operators have invested heavily to upgrade their cable infrastructure in order to provide cable modem services. These investments are starting to pay-off. Cable operators are particularly enthusiastic about cable modem services attractive operating margins. With the cost of cable modem equipment rapidly decreasing, many USA cable operators are enjoying monthly operating margins that range from 50% to 100%. By Geographic region, USA has the most cable modem subscribers with over 14.6 million. The Asia-pacific regions was second with 6.6 million, followed by Europe with 3.7 million.

5 IV. CONCLUSIONS With next generation cable access network cable operators can provide integrated voice, data and video services to their customers by using Internet protocol based network. With this broadband solution cable service providers find new ways to generate additional revenue. To succeed in today s economic climate, cable operators must migrate their existing operations support systems to next generation cable access network that support the emerging voice/video/data conveyed network-all while meeting even more stringent customer demands. They are confronted with the need to reduce operational costs while increasing overall operational efficiency, and identifying and meeting customer expectations. ACKNOWLEDGEMENT The author is grateful to Sh. Pradeep Kumar, country Director, for his encouragement and permission to present this paper. REFERENCES [1] Data-over-cable service interface specifications-rf interface specification, SP-RFI-I , Cable Television Laboratories, Nov.1999, Louisville, Colorado [2] B.Bernath, Programmable cable modem architectures support multiple standards, Nikkei Electronics Asia, pp I-8 to I-12, Oct [3] What is the future holds for the cable modem, cable & satellite International, pp 14-16, Jan-Feb.2001 [4] B.M.J.Ellis, Broadband over cable networks, Broadcast Engineering,Vol.44, no.4, pp 10-12, April,2003 [5] Broadcasting and cable on line,