Friday, January 18, 2002 2:37:46 PM
FPGAs in Wireless Networking
by
Ashwin Jeyapalasingam
under the supervision of
Prof. Ian Page
Introduction to Wireless Networking
In the last few years, developments in wireless networking have been phenomenal. Rapid advances in technology have helped to bring mobile communication to the hands of the consumer. Mobile phones are increasingly popular and the Internet and WAP (wireless application protocol) are now household terms. Statistics have shown that 1 in 6 people in the UK and 1 in 15 people in the world owns a personal mobile phone.
There is a demand for wireless networks both at home, the workplace as well as in telecommunications. At homes, consumers currently require wireless solutions to avoid having to deal with complicated wiring or installation of phone jacks, etc. In the future, though, it is predicted that ordinary household devices (e.g. toaster, stove, microwave) will interact with each other. For example, if you decided to have breakfast, the grill would begin cooking the sausages and the toaster would begin toasting the bread once it received the signal from the grill that the sausages were 2 minutes to completion. Imagining wiring from all household appliances to each other is a nightmare - hence the inception of the idea of wireless technology at home. The technology must be simple to install for the consumer, easy to use and economical. It must provide bandwidth to support common home networking applications, while not compromising the security of the home. (see Bluetooth, HomeRF)
In many large corporations, wireless networking is already being implemented. With a large number of computer terminals and peripherals networked together, cabling is not always a feasible solution. Wireless networking provides the business user with mobility - a connection to the Internet and the ability to access data, wherever, whenever. Wireless LANs also allow handheld devices and notebook PCs to transmit real-time information to centralized hosts for processing. (see Wireless LAN, IEEE 802.11, HiperLAN2, VoiP)
In telecommunications, wireless solutions are becoming more and more attractive for several reasons:
Prohibitive costs in cabling over long distances, to multiple points
Speed advantages using EMF (electromagnetic frequency) waves
Large bandwidth
The biggest excitement in telecommunications this year has been the development of third-generation (3G) mobile network standards. (see Cellular networks, W-CDMA)
Technologies in Wireless Networking
HomeRF
The HomeRF Working Group (HRFWG) was formed in March 1998 to provide the foundation for a broad range of interoperable consumer devices by establishing an open industry specification for wireless digital communication. The HRFWG, developed a specification for wireless communications in the home called the Shared Wireless Access Protocol (SWAP) to suit the consumer needs of homes and SOHOs (Small Office Home Office).
The HRFWG believes that the open SWAP specification will break through these barriers by
Enabling interoperability between many different consumer electronic devices available from a large number of manufacturers, and
providing the flexibility and mobility of a wireless solution. This flexibility is important to the success of creating a compelling and complete home network solution.
HomeRF was created to provide low cost, voice and data capabilities Voice support is provided by DECT using frequency hopping in the 2.4 GHz band. For data, the HomeRF spec uses a relaxed specification of the TCP/IP support of IEEE 802.11.
Bluetooth
The development of Bluetooth began in early 1998 and was led by several telecommunications and computer industry leaders Bluetooth Special Interest Group (SIG). The Bluetooth specification is open and royalty-free, and available to anyone who wishes to use it in their products.
Bluetooth is a low power radio technology developed to replace the wires currently used to connect electronic devices such as PCs, printers PDAs and mobile phones. It enables users to connect a wide range of computing and telecommunications devices with ease, without the hassle of cables.
Bluetooth operates in the 2.4GHz ISM (Industrial, Scientific, Medical) band. Devices equipped with Bluetooth should be capable of exchanging data at speeds up to 720kbit/s at ranges up to 10 meters. This is achieved using a transmission power of 1mW and the incorporation of frequency hopping to avoid interference. If the receiving device detects that the transmitting device is closer than 10 meters it will automatically modify its transmitting power to suit the range. The device should also shift to a low-power mode as soon as traffic volume becomes low or ceases altogether. Future revisions to the Bluetooth specification are being developed and intend extending current data rates to support applications that need higher bandwidths.
As Bluetooth penetrates the consumer market, existing products will become Bluetooth enabled. Digital modems, residential gateways, set-top boxes, and SOHO routers provide high-speed access to the Internet. The Bluetooth module when integrated to the system will enable high-speed Internet access to other Bluetooth devices.
Wireless LAN
Business Research Group predicts the worldwide wireless LAN market revenues to grow to more than $2 billion revenues by the year 2000.
The two popular wireless LAN technologies are the IEEE 802.11 and HiperLAN2. A variation of IEEE 802.11 supports data rates of 11 Mbps and a range of 100 meters, but it is most popular in the US. The HiperLAN2 is the fastest growing wireless LAN technology with a proposed data rate of 54 Mbps and a range over 150 meters. The IEEE 802.11 and HiperLAN2 standards are focussing on telecommuters, SOHOs, and hospitals to make the biggest impact.
Wireless LANs combine data connectivity with user mobility and provide a good general purpose connectivity alternative for a broad range of business customers.
IEEE 802.11
IEEE 802.11 is the standard for Wireless Local Area Networks (WLANs) developed by the Institute of Electrical and Electronics Engineers (IEEE). It can be compared to the 802.3 standard for ethernet wired LANs. The goal of this standard is to tailor a model of operation in order to resolve compatibility issues between manufacturers of WLAN equipment manufacturers.
There are 2 variations of IEEE 802.11: a and b.
The IEEE 802.11 standard addresses the 2.4 GHz and 5 GHz WLAN markets. The specification is steered by the IEEE committee and it specifies an "over the air" interface between a wireless client and a base station (access point) or wireless clients. The specification was conceived in 1990, and the final draft was approved in June 1997. Just like the the IEEE 802.3 Ethernet and 802.5 Token Ring standards IEEE 802.11 addresses both physical and medium access control (MAC) layers.
IEEE 802.11 standard is based on IEEE 802.3 standard (or Ethernet), which is a CSMA/CD technology. CSMA (Carrier Sense Multiple Access) technology is excellent for wireless where there is distributed control with listen before talking. CD (Collision Detection) is not good for wireless LANs and will not work well in an RF system, because the transmitting signal hears its own signal perfectly. Also, the radio is a much more lossy medium with a much higher packet error rate.
HiperLAN2
The HiperLAN2 is the fastest growing wireless LAN technology with a proposed data rate of 54 Mbps and a range over 150 meters.
(Unfortunately at the time of writing this report, I seem to have lost my information on the HiperLAN2)
Cellular Radio
Cellular radio is a worldwide market, with the goal of providing universal wireless voice and data access. IMT-2000 provides a global set of standards for radio network compatibility.
Since its initial market debut in 1980, the cellular mobile telecommunications market has experienced explosive growth in consumer acceptance. The first generation wireless systems were analogue cellular with standards like AMPS, ETACS and NMT. These systems primarily carried voice data, with slow digital data rates. The second-generation systems migrated towards digital cellular with standards like GSM, PDC, DAMPS and CDMA. The second-generation systems also included cordless phones and satellite communications (Iridium, Globalstar, etc). Today the mobile systems of the world are mostly digital leading to the development of global third-generation standards like IMT-2000 / UMTS. In the International Telecommunications Union (ITU), third-generation networks are called IMT-2000, but in Europe they are referred to as UMTS.
Today, there is tremendous excitement about the development of 3G (third-generation) digital wireless telecommunication systems. Two major forces are driving the development of these 3G systems. The first is the demand for higher data rate services, such as high-speed wireless Internet access. The second requirement is the more efficient use of the available radio frequency (RF) spectrum. This second requirement is a consequence of the projected growth in worldwide usage of wireless services. W-CDMA is the emerging wireless multiple access scheme for IMT-2000 / UMTS.
IMT-2000 is a flexible standard that allows operators the freedom of radio access methods and core networks to openly implement and evolve their systems depending on regulatory, market or business requisites.
3G Wireless Network Infrastructure
W-CDMA
Wideband Code Division Multiple Access (WCDMA) is a 3rd-generation mobile services platform, based on modern, layered network-protocol structure, similar to the protocol structure used in GSM networks. This will greatly facilitate the development of new wireless wideband multimedia applications, allowing operators to respond in a competitive market and in turn providing advanced services for users.
From the start, WCDMA has been designed for high-speed data services and, more particularly, internet-based packet-data offering up to 2 Mbps in stationary or office environments, and up to 384 kbps in wide area or mobile environments.
It has been developed and optimised with no requirements on backward compatibility with second-generation technology. In the radio base station infrastructure-level, WCDMA makes efficient use of radio spectrum to provide considerably more capacity and coverage than current air interfaces.
Wideband Packet CDMA (WP-CDMA) is a technical proposal from Golden Bridge Technology that supposedly wraps WCDMA and CDMA2000 (from the CDG Group) into one standard. The WP-CDMA proposal employs CDMA parameters that have gained wide acceptance in both Europe and Japan, raising hopes for a truly global standard for third-generation radio access to networks.
Advantages of Using FPGAs in Wireless Networking
The reconfigurability of FPGAs provides designers with the flexibility to implement fast, efficient, and cost-effective field upgrades. This is especially important in the wireless industry, where existing standards are constantly evolving. FPGA reconfigurability allows for system upgrades resulting from new system features, bug fixes, or evolving standards without an impact on hardware or board layout. This is impossible in the ASIC world thereby making the use of FPGAs a cost-effective solution. Another advantage of FPGAs is that they are in-system re-configurable enabling remote field upgrades. These features enable the next generation wireless products to be designed more efficiently.
FPGAs have architectural features that are ideal for implementing wireless systems. Architectural features, such as serial Shift Register LUTs (Look Up Table), fast adder carry chains, and efficient multiplier implementations, make FPGAs very efficient at repetitive DSP algorithm implementations and high performance wireless applications. These FPGAs often have integrated support for many I/O standards, enabling seamless interface to other devices in the system.
Some signal processing requirements go well beyond the capability of generic DSPs. With FPGAs dedicated hardware functionality can be implemented to achieve the required speeds. Also, with the multi-million-gate FPGAs, hardware functionality can be replicated to support multiple channels.
The wireless network market is very competitive and time to market is particularly important. Using FPGAs cuts down that vital time, since designers no longer have to wait out the turnaround times of ASIC development.
Systems often require multiple revisions. As a result, ASICs are not a viable platform. FPGAs provide the flexibility to implement new proprietary features/standards. It must also cater for improvements in capacity enhancement techniques and remote in-field upgrades. It is difficult to justify the high non-recurring engineering (NRE) costs associated with ASICs when developing a system for a technology that is still in development.
Conclusion
Wireless technologies have both advantages and disadvantages. Advantages include flexibility and mobility by providing the ability to access data anywhere, anytime. Wireless networks support a broad geography on any specific frequency. The biggest advantage wireless technologies bring is configuring them to augment wired technologies. However, wireless technologies usually have higher up-front costs compared to wired solutions. However, the chief disadvantage of wireless networking is that of security. 'Eavesdropping' on a wireless network is much easier because there is no physical connection. Another main disadvantage is that of narrowband interference due to reflections, but current advancements in technology have helped reduce the effects of this.
FPGAs play an important role in wireless networks chiefly because of its reconfigurability. It is a new industry with emerging standards and conventions. While this may take many years to resolve, using FPGAs allow users today to continue using the current technologies of their choice with the option of evolving without prohibitive costs. FPGAs are flexible in allowing revisions and modifications to the system to implement new proprietary features; and allow remote in-field upgrades. Another chief advantage lies in time to market. With development of new technologies every day, time to market is an essential factor. FPGAs cut down that time significantly as designers no longer have to wait out the turnaround time of ASIC development.
For these reasons and more, we predict the growing importance of FPGAs in the wireless industry will be a trend and not a fad. Viva la FPGA!
http://infoeng.ee.ic.ac.uk/~malikz/surprise2001/aj99e/article2/index.html
by
Ashwin Jeyapalasingam
under the supervision of
Prof. Ian Page
Introduction to Wireless Networking
In the last few years, developments in wireless networking have been phenomenal. Rapid advances in technology have helped to bring mobile communication to the hands of the consumer. Mobile phones are increasingly popular and the Internet and WAP (wireless application protocol) are now household terms. Statistics have shown that 1 in 6 people in the UK and 1 in 15 people in the world owns a personal mobile phone.
There is a demand for wireless networks both at home, the workplace as well as in telecommunications. At homes, consumers currently require wireless solutions to avoid having to deal with complicated wiring or installation of phone jacks, etc. In the future, though, it is predicted that ordinary household devices (e.g. toaster, stove, microwave) will interact with each other. For example, if you decided to have breakfast, the grill would begin cooking the sausages and the toaster would begin toasting the bread once it received the signal from the grill that the sausages were 2 minutes to completion. Imagining wiring from all household appliances to each other is a nightmare - hence the inception of the idea of wireless technology at home. The technology must be simple to install for the consumer, easy to use and economical. It must provide bandwidth to support common home networking applications, while not compromising the security of the home. (see Bluetooth, HomeRF)
In many large corporations, wireless networking is already being implemented. With a large number of computer terminals and peripherals networked together, cabling is not always a feasible solution. Wireless networking provides the business user with mobility - a connection to the Internet and the ability to access data, wherever, whenever. Wireless LANs also allow handheld devices and notebook PCs to transmit real-time information to centralized hosts for processing. (see Wireless LAN, IEEE 802.11, HiperLAN2, VoiP)
In telecommunications, wireless solutions are becoming more and more attractive for several reasons:
Prohibitive costs in cabling over long distances, to multiple points
Speed advantages using EMF (electromagnetic frequency) waves
Large bandwidth
The biggest excitement in telecommunications this year has been the development of third-generation (3G) mobile network standards. (see Cellular networks, W-CDMA)
Technologies in Wireless Networking
HomeRF
The HomeRF Working Group (HRFWG) was formed in March 1998 to provide the foundation for a broad range of interoperable consumer devices by establishing an open industry specification for wireless digital communication. The HRFWG, developed a specification for wireless communications in the home called the Shared Wireless Access Protocol (SWAP) to suit the consumer needs of homes and SOHOs (Small Office Home Office).
The HRFWG believes that the open SWAP specification will break through these barriers by
Enabling interoperability between many different consumer electronic devices available from a large number of manufacturers, and
providing the flexibility and mobility of a wireless solution. This flexibility is important to the success of creating a compelling and complete home network solution.
HomeRF was created to provide low cost, voice and data capabilities Voice support is provided by DECT using frequency hopping in the 2.4 GHz band. For data, the HomeRF spec uses a relaxed specification of the TCP/IP support of IEEE 802.11.
Bluetooth
The development of Bluetooth began in early 1998 and was led by several telecommunications and computer industry leaders Bluetooth Special Interest Group (SIG). The Bluetooth specification is open and royalty-free, and available to anyone who wishes to use it in their products.
Bluetooth is a low power radio technology developed to replace the wires currently used to connect electronic devices such as PCs, printers PDAs and mobile phones. It enables users to connect a wide range of computing and telecommunications devices with ease, without the hassle of cables.
Bluetooth operates in the 2.4GHz ISM (Industrial, Scientific, Medical) band. Devices equipped with Bluetooth should be capable of exchanging data at speeds up to 720kbit/s at ranges up to 10 meters. This is achieved using a transmission power of 1mW and the incorporation of frequency hopping to avoid interference. If the receiving device detects that the transmitting device is closer than 10 meters it will automatically modify its transmitting power to suit the range. The device should also shift to a low-power mode as soon as traffic volume becomes low or ceases altogether. Future revisions to the Bluetooth specification are being developed and intend extending current data rates to support applications that need higher bandwidths.
As Bluetooth penetrates the consumer market, existing products will become Bluetooth enabled. Digital modems, residential gateways, set-top boxes, and SOHO routers provide high-speed access to the Internet. The Bluetooth module when integrated to the system will enable high-speed Internet access to other Bluetooth devices.
Wireless LAN
Business Research Group predicts the worldwide wireless LAN market revenues to grow to more than $2 billion revenues by the year 2000.
The two popular wireless LAN technologies are the IEEE 802.11 and HiperLAN2. A variation of IEEE 802.11 supports data rates of 11 Mbps and a range of 100 meters, but it is most popular in the US. The HiperLAN2 is the fastest growing wireless LAN technology with a proposed data rate of 54 Mbps and a range over 150 meters. The IEEE 802.11 and HiperLAN2 standards are focussing on telecommuters, SOHOs, and hospitals to make the biggest impact.
Wireless LANs combine data connectivity with user mobility and provide a good general purpose connectivity alternative for a broad range of business customers.
IEEE 802.11
IEEE 802.11 is the standard for Wireless Local Area Networks (WLANs) developed by the Institute of Electrical and Electronics Engineers (IEEE). It can be compared to the 802.3 standard for ethernet wired LANs. The goal of this standard is to tailor a model of operation in order to resolve compatibility issues between manufacturers of WLAN equipment manufacturers.
There are 2 variations of IEEE 802.11: a and b.
The IEEE 802.11 standard addresses the 2.4 GHz and 5 GHz WLAN markets. The specification is steered by the IEEE committee and it specifies an "over the air" interface between a wireless client and a base station (access point) or wireless clients. The specification was conceived in 1990, and the final draft was approved in June 1997. Just like the the IEEE 802.3 Ethernet and 802.5 Token Ring standards IEEE 802.11 addresses both physical and medium access control (MAC) layers.
IEEE 802.11 standard is based on IEEE 802.3 standard (or Ethernet), which is a CSMA/CD technology. CSMA (Carrier Sense Multiple Access) technology is excellent for wireless where there is distributed control with listen before talking. CD (Collision Detection) is not good for wireless LANs and will not work well in an RF system, because the transmitting signal hears its own signal perfectly. Also, the radio is a much more lossy medium with a much higher packet error rate.
HiperLAN2
The HiperLAN2 is the fastest growing wireless LAN technology with a proposed data rate of 54 Mbps and a range over 150 meters.
(Unfortunately at the time of writing this report, I seem to have lost my information on the HiperLAN2)
Cellular Radio
Cellular radio is a worldwide market, with the goal of providing universal wireless voice and data access. IMT-2000 provides a global set of standards for radio network compatibility.
Since its initial market debut in 1980, the cellular mobile telecommunications market has experienced explosive growth in consumer acceptance. The first generation wireless systems were analogue cellular with standards like AMPS, ETACS and NMT. These systems primarily carried voice data, with slow digital data rates. The second-generation systems migrated towards digital cellular with standards like GSM, PDC, DAMPS and CDMA. The second-generation systems also included cordless phones and satellite communications (Iridium, Globalstar, etc). Today the mobile systems of the world are mostly digital leading to the development of global third-generation standards like IMT-2000 / UMTS. In the International Telecommunications Union (ITU), third-generation networks are called IMT-2000, but in Europe they are referred to as UMTS.
Today, there is tremendous excitement about the development of 3G (third-generation) digital wireless telecommunication systems. Two major forces are driving the development of these 3G systems. The first is the demand for higher data rate services, such as high-speed wireless Internet access. The second requirement is the more efficient use of the available radio frequency (RF) spectrum. This second requirement is a consequence of the projected growth in worldwide usage of wireless services. W-CDMA is the emerging wireless multiple access scheme for IMT-2000 / UMTS.
IMT-2000 is a flexible standard that allows operators the freedom of radio access methods and core networks to openly implement and evolve their systems depending on regulatory, market or business requisites.
3G Wireless Network Infrastructure
W-CDMA
Wideband Code Division Multiple Access (WCDMA) is a 3rd-generation mobile services platform, based on modern, layered network-protocol structure, similar to the protocol structure used in GSM networks. This will greatly facilitate the development of new wireless wideband multimedia applications, allowing operators to respond in a competitive market and in turn providing advanced services for users.
From the start, WCDMA has been designed for high-speed data services and, more particularly, internet-based packet-data offering up to 2 Mbps in stationary or office environments, and up to 384 kbps in wide area or mobile environments.
It has been developed and optimised with no requirements on backward compatibility with second-generation technology. In the radio base station infrastructure-level, WCDMA makes efficient use of radio spectrum to provide considerably more capacity and coverage than current air interfaces.
Wideband Packet CDMA (WP-CDMA) is a technical proposal from Golden Bridge Technology that supposedly wraps WCDMA and CDMA2000 (from the CDG Group) into one standard. The WP-CDMA proposal employs CDMA parameters that have gained wide acceptance in both Europe and Japan, raising hopes for a truly global standard for third-generation radio access to networks.
Advantages of Using FPGAs in Wireless Networking
The reconfigurability of FPGAs provides designers with the flexibility to implement fast, efficient, and cost-effective field upgrades. This is especially important in the wireless industry, where existing standards are constantly evolving. FPGA reconfigurability allows for system upgrades resulting from new system features, bug fixes, or evolving standards without an impact on hardware or board layout. This is impossible in the ASIC world thereby making the use of FPGAs a cost-effective solution. Another advantage of FPGAs is that they are in-system re-configurable enabling remote field upgrades. These features enable the next generation wireless products to be designed more efficiently.
FPGAs have architectural features that are ideal for implementing wireless systems. Architectural features, such as serial Shift Register LUTs (Look Up Table), fast adder carry chains, and efficient multiplier implementations, make FPGAs very efficient at repetitive DSP algorithm implementations and high performance wireless applications. These FPGAs often have integrated support for many I/O standards, enabling seamless interface to other devices in the system.
Some signal processing requirements go well beyond the capability of generic DSPs. With FPGAs dedicated hardware functionality can be implemented to achieve the required speeds. Also, with the multi-million-gate FPGAs, hardware functionality can be replicated to support multiple channels.
The wireless network market is very competitive and time to market is particularly important. Using FPGAs cuts down that vital time, since designers no longer have to wait out the turnaround times of ASIC development.
Systems often require multiple revisions. As a result, ASICs are not a viable platform. FPGAs provide the flexibility to implement new proprietary features/standards. It must also cater for improvements in capacity enhancement techniques and remote in-field upgrades. It is difficult to justify the high non-recurring engineering (NRE) costs associated with ASICs when developing a system for a technology that is still in development.
Conclusion
Wireless technologies have both advantages and disadvantages. Advantages include flexibility and mobility by providing the ability to access data anywhere, anytime. Wireless networks support a broad geography on any specific frequency. The biggest advantage wireless technologies bring is configuring them to augment wired technologies. However, wireless technologies usually have higher up-front costs compared to wired solutions. However, the chief disadvantage of wireless networking is that of security. 'Eavesdropping' on a wireless network is much easier because there is no physical connection. Another main disadvantage is that of narrowband interference due to reflections, but current advancements in technology have helped reduce the effects of this.
FPGAs play an important role in wireless networks chiefly because of its reconfigurability. It is a new industry with emerging standards and conventions. While this may take many years to resolve, using FPGAs allow users today to continue using the current technologies of their choice with the option of evolving without prohibitive costs. FPGAs are flexible in allowing revisions and modifications to the system to implement new proprietary features; and allow remote in-field upgrades. Another chief advantage lies in time to market. With development of new technologies every day, time to market is an essential factor. FPGAs cut down that time significantly as designers no longer have to wait out the turnaround time of ASIC development.
For these reasons and more, we predict the growing importance of FPGAs in the wireless industry will be a trend and not a fad. Viva la FPGA!
http://infoeng.ee.ic.ac.uk/~malikz/surprise2001/aj99e/article2/index.html
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