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Toys Article - August 2001 - [Home Page] |
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by Amit Dhir, Xilinx Corporation |
The
gateway provides a unified platform to satisfy the needs of most
consumers, providing infotainment and communication. It is a centralized
access point between the home and the Internet. Since
the underlying technologies are new and evolving, the Residential Gateway
will evolve in
its functionality. In its basic form it will combine digital modems, home
networking chipsets, and software. |
Introduction
The Residential Gateway (RG), also known as service gateway, media gateway or home gateway, is the key ingredient to providing ubiquitous high-speed Internet access to consumer devices. It provides a platform to bring broadband access (via DSL, wireless, cable or satellite) into your house and connect or bridge to home networking technologies (like HomePNA, HomeRF, wireless LANs or IEEE1394). This enables communication between networked appliances (such as digital TV, gaming consoles, Web pads) in the home and across the Internet.
The evolution of new data broadcasting services has created the need for a device to pass digital content between the Internet and home network. Residential Gateway is a platform for the deployment of high-speed Internet access and integrated voice, data and video services over the same high-speed pipe to different nodes (appliances) throughout the home. Residential Gateways combine the functions of a digital modem, SOHO router or hub for Internet access to multiple information appliances.
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Market Trends
The home networking market is fragmented and includes the following four aspects:
- Broadband access
- Residential Gateway
- Home networking technologies: no new wires (phonelines, powerlines), new wires (IEEE1394, Ethernet, USB2.0), and wireless (HomeRF, Bluetooth, DECT, IEEE802.11, HiperLAN2)
- Information/Internet appliances
Rapid implementation of integrated value-add services with home networking is creating an explosive market for Residential Gateways. Cahners In-Stat Group predicts the Residential Gateway market will rise sharply from $100 million in 2000 to $5 billion in 2005.
Residential Gateways will evolve from providing basic broadband access to providing integrated services gateways such as remote management, home automation, home security and video-on-demand. This will also network multiple home networking technologies and provide protocol translation between disparate technologies. The Residential Gateway market drivers include:
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Home networking
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Increased demand for non-PC based appliances
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TV-centric applications and other service offerings
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The Internet is proving to be an important market driver for Residential Gateways. The Residential Gateway will control the flow of information between home appliances and the ubiquitous Internet. With lower PC costs, consumers are having multiple PCs in the home. However, for a single broadband connection for Internet access, this one access point requires some type of Residential Gateway device.
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Service providers and network operators intend to expand their revenue streams and offer non-traditional services. To allow them manage these new services, the network operators are working very closely with a number of vendors to develop Residential Gateways that will be capable of supporting the new services.
Consortiums like the OSGi (Open Services Gateway Initiative) are working to define and promote an open Residential Gateway standard for connecting the coming generation of smart consumer and small business appliances with commercial Internet services. Hurdles inhibiting the mass deployment of Residential Gateways in households include the lack of:
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Clear business models (costs of ownership)
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Customer education and mass confusion
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Support mechanisms
Mass deployment of gateways into homes will come in three distinct phases. While the gateway is a new term, it already exists in many homes. Most of our homes have a set-top box for receiving television and a modem to connect to the Internet. Phase two includes advanced features such as broadband connectivity, home networking interfaces and IP telephony in the Residential Gateway . The third deployment phase will be powerful Residential Gateways, capable of delivering video, voice and data throughout the home. It will provide other services such as home automation, energy management, security control, etc.
The hardware architecture will be modular in design, which allows support of multiple broadband and home networking technologies. Supporting multiple technologies makes the gateway less apt to becoming obsolete with technology advancements. Support for modularity will fuel the evolution of Residential Gateways into a type of application server that consumers will use to distribute broadband services throughout their homes. The gateway must have a reliable and robust hardware platform, and software that is not susceptible to errors. Unlike PC users, consumers will not stand rebooting their gateways. Supporting multiple services such as voice, data and video with complete security is essential. Functions such as e-commerce transactions, and remote home control and access from authorized service providers are critical. Providing quality of service to support multiple intelligent devices from different vendors is extremely important.
Residential Gateway Components
The gateway provides a unified platform to satisfy the needs of most consumers, providing infotainment and communication. It is a centralized access point between the home and the Internet. Since the underlying technologies are new and evolving, the Residential Gateway will evolve in its functionality. In its basic form it will combine digital modems, home networking chipsets, and software. Digital modem chipsets provide connectivity to different broadband networks, and home networking chipsets provide interconnectivity technologies between appliances. Additionally, all gateways contain computing resources to support the software required to operate the device. The software running on the Residential Gateway enables the smooth interoperation of information appliances and services within the home, to eliminate the complexity, distribution, and technical disparity of the system elements.
Types of Residential Gateways
Various types of devices are competing for a share of the Residential Gateway marketplace – PCs, broadband modems, set-top boxes and others.
PC-based Residential Gateway (Home Servers)
The PC-based Residential Gateway could be the easiest path to the Residential Gateway because of PC penetration in today's affluent home. Also, it has the processing power, includes a digital modem and is an ideal platform for the deployment of home networking services. However, the PC has certain disadvantages. The operating systems are traditionally not robust, and the PC crashing and requiring rebooting is not acceptable in a gateway, which provides critical features such as security. Some companies have pursued PC-based architectures even within a separate Residential Gateway .
Modem-centric Residential Gateways
Traditional methods to connect to the Web have hit a technological upside. Analog modems using phonelines cannot provide bandwidth beyond 56Kbps. Digital modems, such as cable, DSL and satellite provide high-speed Internet access. Satellite modems offer speeds of 400Kbps to 38Mbps, DSL modems offer 1.5Mbps to 52Mbps and cable modems process multimedia content upto 30Mbps. Usually the Residential Gateway is sold in conjunction with value-add services. Service providers subsidize the cost of the gateway by charging for services over 1-2 years. Usually the gateway is easy to install and the service provider saves money by minimizing truck rolls. The following types of broadband modems will evolve into a gateway.
Cable Modems
Historically, cable companies offer TV services to their customers. These companies are moving into offering services such as high-speed Internet access, free e-mail accounts, web hosting of e-commerce sites and IP-based voice applications. To capitalize on this new opportunity, operators are upgrading their networks to support these new and exciting applications. Cable modems are client devices that provide high-speed, two-way communication (data, voice and video) over the ordinary cable TV network cables to access this mix of applications. Cable modems provide an always on connection, thus eliminating the slow and frustrating procedure of establishing a dial-up connection.
A standard cable modem has two connections; one port connected to the TV outlet on the wall and the other to the home network. The cable modem communicates over the cable network to a device called a CMTS (Cable Modem Termination System), which is a central device for connecting the cable TV network to a data network (Internet).
The cable modem speeds depend on traffic levels and the overall network architecture. Theoretically, cable modems are capable of receiving and processing multimedia content at 30Mbps. However, subscribers can expect to download information at 1.5Mbps, because multiple users in the neighborhood share the bandwidth. Operators define a portion of the frequency spectrum to carry the data. The downstream path (head-end to home network) lies between 50MHz and 750MHz. The 5-42 MHz frequency range transmits information from the home network to the head-end. Cable modems receive and transmit TCP/IP traffic including multimedia content and Internet access.
Figure
1: Cable modem-based gateway
The tuner in the cable modem receives a digital signal from the network and isolates a particular channel that contains the Internet data. It then converts the signal from RF levels back to baseband. The baseband output signal from the tuner is then forwarded to a demodulator. The demodulator samples the signal and converts it to a digital bit-stream. The bit-stream contains video, audio and IP data. Once the bit-stream is recovered it is forwarded to forward error correction (FEC) unit and checked for problems. The signal is then passed into the control unit and further to the home network using one of the high-speed data port interfaces.
In a cable modem-based gateway (figure 1), programmable logic solutions provide system interfacing (PCI, UART, DMA), encryption, interfacing to several home networking technologies (Ethernet, USB 2.0, HomePNA), ASSP (Application Specific Standard Product) functionality (such as cable MAC (Media Access Control (sub-layer)) and glue logic.
Satellite Modems
Similar to the cable operators, satellite service providers deliver broadband connections to their subscribers. Consumers who connect their home networks to a satellite broadband platform are accessing a shared media that is broadcasting at rates up to 38Mbps. The transmission speeds from the service provider to the home is high, but the upload speeds are limited to a dial-up, telephone modem transmission rates. This high-speed connection is facilitated through a dish and satellite modem.
Figure 2: Satellite
Modem-based Gateway
In a satellite modem the interface receives digital signals from the satellite network and isolates channels containing Internet data. It converts the analog signal to a digital format, and checks errors. The host interface provides an interface between the satellite modem and home network, using USB and PCI host interfaces. System glue interconnects the CPU and memory components with the host and satellite interfaces. Satellite modem-based gateways (figure 2) include satellite modem ASSPs and home networking ASSPs. They provide high-speed (data, voice and video) access (using the satellite broadband network) and network these information appliances. Programmable logic provides system interconnectivity solutions to network appliances using disparate technologies such as phonelines or Ethernet.
DSL Modems
Broadband modems based on DSL technology support data transmission over standard telephone lines upto 50 times faster than the analog modems. An Asymmetric Digital Subscriber Line (ADSL) circuit consists of two ADSL modems connected by a copper twisted-pair telephone line. To maintain backward compatibility with the standard telephone system and to avoid disruption of service due to equipment failure, the voice part of the frequency spectrum is separated from the digital modem circuitry by means of a passive filter called a ‘POTS splitter’. Hence, if the ADSL service fails, the POTS service is still available. Under this configuration, voice calls and Internet data are transmitted simultaneously over the same broadband DSL pipe. When an ADSL transmission is received at the central office, a more advanced POTS splitter is used to send the voice traffic to the public telephone network and data to the Internet. Using a DSL modem as a gateway has become significantly easier over the past couple of years, as PC manufacturers ship PCs with high-speed DSL modems.
Figure 3: DSL-modem based Home Gateway
DSL gateways provide DSL functionality and network information appliances. Programmable solutions are ideal for interfacing multiple home networking technologies (such as HomePNA, Ethernet, and USB2.0) and system interfaces such as PCI.
Digital set-top boxes (STBs)
In the early seventies, the only piece of equipment that people needed to watch TV was a standard television that they were able to purchase at their local store. In the 1980s, this simple model began to change. Cable and satellite providers required the consumer to connect their TVs to their networks. Also, operators decided to scramble TV signals, requiring a special box to de-scramble the signals at the consumers home. Today digital television requires a set-top boxe to receive and decode digital transmissions into a form suitable for display on analog television sets. A set-top boxe is one of a complex electronics device comprised of a myriad of hardware and software components, usually connected to the TV set and the cable connection on the wall. They are installed and configured by the local cable, terrestrial or satellite service provider. set-top boxes translate digital signals into a format, which can be viewed on a television screen.
Digital set-top boxes are classified into low cost entry–level, mid range and advanced categories. Entry level set-top boxes are capable of providing traditional broadcast television and pay-per-view, with a basic navigation tool. They have no return channel, and therefore do not interact with computer servers located at the head-end. Entry level set-top boxes are low cost and come with limited quantities of memory, interface ports and processing power.
Mid-range set-top boxes include a return (back) channel, which provides communication with a server located at the head-end. These set-top boxes provide e-commerce, Internet browsing, and multimedia services. The return channel further allows for customized broadcasts to the local viewing population. The mid-range set-top boxes have higher processing power and memory than entry-level set-top boxes.
Figure 4: Digital
set-top boxe
Advanced set-top boxes are like multimedia desktop computers, containing much higher processing power than other set-top boxes. Enhanced capabilities in conjunction with a high-speed return path can be used to access a variety of advanced services such as video teleconferencing, home networking, IP telephony, video-on-demand, and high-speed Internet TV services. Additionally, it has enhanced graphical capabilities to receive high definition TV signals and can store video on a hard disk drive and provide the capability to record and view video simultaneously. Such receivers have a range of high-speed interface ports, and hence resemble Residential Gateways. For cable, terrestrial, and satellite companies, set-top boxes that support advanced technologies is an opportunity to increase revenue streams through providing services.
set-top boxes usually have cable or satellite modem chips to bring broadband and TV signals to the home. Other ASSPs/ASICs (Application Specific Integrated Circuits) handle and process digital video and audio services. These ASSPs communicate with each other via buses on the system board. The CPU is responsible for coordinating the different components. With additional features, set-top boxes will require higher performance CPUs to keep pace with increased data throughput. There are three types of set-top boxe software, namely, operating systems, middleware and applications. The operating system operate the set-top boxe parts. The middleware is a layer of software programs that operates between the interactive TV applications and the operating system. Viewers use application software to watch TV and use interactive features.
The set-top boxe market is very dynamic and will change dramatically over the next few years. set-top boxes will evolve into multimedia servers, forming the hub of the home network for primary access to the Internet, i.e., the Residential Gateway . Programmable logic devices address the fundamental disconnect between ASSPs. Time-to-market and the ability to upgrade quickly is imperative for a successful product. This provides the cutting edge to bring products first to market, while having the ability to remotely add features to the set-top boxe already deployed in the home.
Other Possible Gateways
While set-top boxe, PC and modem-based gateways seem conceivable ideas, gaming consoles, digital video recorders (DVRs or digital VCRs) and utility metering devices provide an imaginative platform to evolve into potential gateways. High-speed game consoles provide enough processing power and interfaces to serve as a gateway to the digital home of the future. Today, DVRs provide an interface to a broadband digital network, but DVR manufacturers will increase support for an interface that provides connectivity to the several home networking technologies. The DVR may evolve into a gateway or its functionality may be absorbed into the set-top boxe. Utility-centric gateways are an interesting part of Residential Gateways, and the concept of a utility company installing a new gateway device in their customers homes to provision new services has been gaining ground since the early 1990s. From a utility company’s perspective, service gateways provide overall cost savings by minimizing truck rolls (through automated meter reading) and energy management. Hardware and installation costs are recovered through provision of services. The push for utility gateways will come from the service provider’s end rather than the consumer.
Need for Programmable Solutions
The Residential Gateway brings broadband access into the home and distributes it within the appliances in the home. For Residential Gateways to be successful, programmable solutions will have to be at the heart of the system. While programmable logic solutions can perform functions of cable MAC SAR (Segmentation, Assembly and Reassembly), DSL receiver chipset and satellite modem chip, their advantage is in interfacing the different broadband and disparate home networking technologies. They provide an ideal interface to access and home networking technologies for protocol translation. Additional features such as DLLs and BlockRAM provide system features such as clock management and glue logic functions. Programmable solutions provide the ability to interface multiple hard-disk drives, proprietary interfaces, and provide encryption capabilities using DES, triple DES and even proprietary encryption schemes. They also provide system interface functions such as PCI, USB, etc. in the gateway.
Figure 5: Residential Gateway
Summary
The primary function of the Residential Gateway is to provide broadband connectivity to the home through cable, xDSL, satellite and wireless. Secondly, Residential Gateways provide home networking capabilities and distribute broadband through information appliances using technologies such as phonelines or wireless LANs. They also provide a unique platform for the deployment of value-add services. This article looked at the evolution of existing PC, digital modems and set-top boxes, and new products into the residential gateway. Programmable logic solutions are necessary for the success of Residential Gateways as they provide time-to-market and time-in-market advantages in interfacing disparate technologies and system interfaces.
Amit Dhir is a system architect in the strategic applications group at Xilinx, primarily responsible for evangelizing new and emerging vertical markets. He was the primary contributor to the Xilinx home networking marketing campaign and eSP web portal. He has published several articles and white papers on topics covering the role for FPGAs in Wireless, Embedded, Telecom, Networking, and Consumer applications, and has authored “The Home Networking Revolution. A Designer’s Guide,” a book that provides a comprehensive overview of the various home networking technologies and components including broadband access, residential gateways, information appliances and middleware. He has a BSEE from Purdue University and a MSEE from San Jose State University, and can be reached at amit.dhir@xilinx.com.
