Intel is working with standards leaders on the next generation of the 802.11 standard. 802.11 is a group of specifications developed by the Institute of Electrical and Electronics Engineers Inc. (IEEE) for wireless local area networks (WLANs). These specifications define an over-the-air interface between a wireless client and a base station (or access point), or between two or more wireless clients.

More popularly, 802.11 is known as Wi-Fi* and is beginning to take the world by storm. Tens of millions of Wi-Fi devices will be sold this year. That includes the majority of notebook computers sold. Most notebooks today have 802.11 capabilities.

Did You Know? The term "Wi-Fi" was the invention of what is now called the Wi-Fi Alliance (WFA — formerly known as the Wireless Ethernet Compatibility Alliance). The WFA decided the term "IEEE 802.11b-compliant" was too long and hard for consumers looking for certified products to remember. "Wi-Fi" meant nothing at the time, but sounded like "hi-fi," a familiar term to consumers. Later on, the meaning "wireless fidelity" was attached to "Wi-Fi."

Analysts predict 100 million people will be using this short-range wireless broadband technology by 2006 (The Economist).

But 802.11 technology innovation is hardly finished yet. In many ways, it seems as if it's just beginning.

Intel is working with the IEEE and Wi-Fi Alliance on the next big thing in wireless networking: the next generation wireless LAN (WLAN) standard. Known as 802.11n, this standard will provide the muscle for data-intensive media, such as multiple HDTV and digital video streams. Researchers expect 802.11n to increase the speed of Wi-Fi connections by up to a factor of ten. Because of limits on their cable or DSL connections, many home users won't benefit from the additional speed right away for Internet access. This new standard will support consumer electronics, PC and handheld platforms though at speeds of 500 Mbps or greater. Businesses are looking to 802.11n to free them from the burden of laying and maintaining Ethernet cabling, as well as handle more clients and increase the range and performance of hotspots.

But before we get too far into where 802.11 is going, let's look at where it is now and how it began.

Wi-Fi sprang into existence as a result of a decision in 1985 by the Federal Communications Commission (FCC) to open several bands of the wireless spectrum for use without a government license. These so-called "garbage bands" were already allocated to equipment such as microwave ovens that use radio waves to heat food. To operate in these bands though, devices would be required to use "spread spectrum" technology. This technology spreads a radio signal out over a wide range of frequencies making the signal less susceptible to interference and difficult to intercept.

In 1990, a new IEEE committee called 802.11 was set up to look into getting a standard started. It wasn't until 1997 though, some 8 or 9 years later, that this new standard was published (though pre-standard devices were already shipping).

South Korea's telecommunications provider KT plans to double the number of its hotspots to 18,000 by the end of 2004. This will give the company the world's largest commercial Wi-Fi network. KT will have more commercial hotspots than all of North America and slightly less than Europe. With entire city blocks as hotspots, South Korea may be the most advanced wireless market on the planet.

Two variants were ratified over the next two years — 802.11b which operates in the Industry, Medical and Scientific (ISM) band of 2.4 GHz and 802.11a which operates in the Unlicensed National Information Infrastructure bands of 5.3 GHz and 5.8 GHz.

Wi-Fi's popularity really took off with the growth of high-speed broadband Internet access in the home. It was and remains the easiest way to share a broadband link between several computers spread over a home. The growth of hotspots, free and fee-based public access points, have added to Wi-Fi's popularity. The latest variant was 802.11g. This Wi-Fi technology, like 802.11a, uses a more advanced form of modulation called orthogonal frequency-division multiplexing (OFDM), but enables it to be used in the 2.4 GHz band. 802.11g can achieve speeds of up to 54 Mbps.

Today 802.11 is rapidly proliferating all over the planet. Nonetheless, it still faces a number of technological challenges. A major one is range. The farthest a device can currently stray and still receive an adequate signal from an 802.11 access point is about 300 feet — and that's if there are no major walls or other substantial physical obstructions. What's more, as any user knows, performance drops off rapidly as you move farther from the access point.

Other major challenges 802.11 faces include how to improve data throughput speeds, enhance security, and improve quality of service. Intel is working on these and other 802.11 issues with other industry leaders all over the world. Let's look at how Intel is helping solve the challenges of range and data throughput speed.

Presently, 802.11a/b/g WLANs provide adequate performance for today's networking applications where the convenience of a wireless connection is the chief value. Next generation wireless applications will require higher WLAN data throughput and people will begin to demand more range. In response to these needs, Intel product groups and Intel research and development are working with both the IEEE 802.11n Task Group and the Wi-Fi Alliance.

The objective of the task group working on 802.11n is to define modifications to the Physical Layer and Media Access Control Layer (PHY/MAC) that deliver a minimum of 100 Mbps throughput at the MAC SAP (service access point).

Wireless LAN Throughput by IEEE Standard

IEEE WLAN Standard Over-the-Air (OTA) Estimates Media Access Control Layer, Service Access Point (MAC SAP) Estimates 802.11b 11 Mbps 5 Mbps 802.11g 54 Mbps 25 Mbps (when .11b is not present) 802.11a 54 Mbps 25 Mbps 802.11n 200+ Mbps 100 Mbps

Table 1. Comparison of different 802.11 transfer rates. (Source: Intel Labs)

This minimum throughput requirement approximately quadruples WLAN throughput performance compared to today's 802.11a/g networks. Over-the-air throughput is targeted to exceed 200 Mbps to meet the 100 Mbps MAC SAP throughput requirement. Other necessary improvements include range at given throughputs, robustness to interference, and an improved and more uniform service within the coverage of an access point (Basic Service Set – BSS). Wider bandwidth channels and multiple antenna configurations could lead to data rates of 500 Mbps.

The task group will also ensure a smooth transition by requiring backward compatibility with existing IEEE WLAN legacy solutions (802.11a/b/g).

Intel has contributed to the development of the 802.11n standard in many ways. Intel chaired the task group committee responsible for the core documents being used to guide the group's development of the 802.11n standard. As part of the task group, Intel contributed to the development of channel models, usage models, functional requirements, and comparison criteria. Intel has also provided technical submissions on MAC and PHY technologies, performance measurement methodologies, and simulation methodologies. For the Wi-Fi Alliance, Intel helped coauthor this certification group's MRD for High Throughput WLANs (marketing requirements document for 802.11n).

One approach Intel is researching to increase the physical transfer rate of 802.11 wireless systems is using multiple antenna systems for both the transmitter and the receiver.

Wireless LAN Standards Chart

802.11 The original WLAN Standard. Supports 1 Mbps to 2 Mbps. 802.11a High speed WLAN standard for 5 GHz band. Supports 54 Mbps. 802.11b WLAN standard for 2.4 GHz band. Supports 11 Mbps. 802.11d International roaming – automatically configures devices to meet local RF regulations 802.11e Addresses quality of service requirements for all IEEE WLAN radio interfaces. 802.11f Defines inter-access point communications to facilitate multiple vendor-distributed WLAN networks. 802.11g Establishes an additional modulation technique for 2.4 GHz band. Supports speeds up to 54 Mbps. 802.11h Defines the spectrum management of the 5 GHz band. 802.11i Addresses the current security weaknesses for both authentication and encryption protocols. The standard encompasses 802.1X, TKIP, and AES protocols. 802.11n Provides higher throughput improvements. Intended to provide speeds up to 500 Mbps.

This technology is referred to as multiple-input multiple-output (MIMO), or smart antenna systems. MIMO exploits the use of multiple signals transmitted into the wireless medium and multiple signals received from the wireless medium to improve wireless performance. Using multiple antennas, MIMO uses spectrum more efficiently without sacrificing reliability.

Intel expects MIMO technology to play an important role in achieving the 802.11n task group goals. MIMO uses multiple diverse antennas tuned to the same channel, each transmitting with different spatial characteristics. Every receiver listens for signals from every transmitter, enabling path diversity where multi-path reflections (normally disruptive to signal recovery) may be recombined to enhance the desired signals.

Another valuable benefit MIMO technology may provide is Spatial Division Multiplexing (SDM). SDM spatially multiplexes multiple independent data streams (essentially virtual channels) simultaneously within one spectral channel of bandwidth. MIMO SDM can significantly increase data throughput as the number of resolved spatial data streams is increased. Each spatial stream requires its own transmit/receive (TX/RX) antenna pair at each end of the transmission. It is important to understand that MIMO technology requires a separate radio frequency (RF) chain and analog-to-digital converter (ADC) for each MIMO antenna. Implementations requiring more than two RF antenna chains will need to be carefully architected to keep costs down while maintaining performance expectations.

Another important tool that can increase the physical transfer rate is wider bandwidth spectral channels. Using a wider channel bandwidth with OFDM offers significant advantages when maximizing performance. Wider bandwidth channels are cost effective and easily accomplished with moderate increases in digital signal processing (DSP). If properly implemented, doubling the legacy bandwidth of 802.11 20 MHz channels to 40 MHz can provide greater than two times the usable channel bandwidth used presently. Coupling MIMO architecture with wider bandwidth channels offers the opportunity of very powerful yet cost effective approaches for increasing the physical transfer rate.

MIMO approaches that use only 20 MHz channels will require higher implementation costs to meet the Task Group n requirement of 100 Mbps throughput at the MAC SAP. Meeting the IEEE Task Group n

Perhaps somewhat surprisingly, the title of "world's first Wi-Fi-linked e-payments network" is claimed by The Mall of San Marino in Guayaquil, Ecuador. To create this network, which supports physical and online retail sales and management for the Mall's 250-plus merchants, Verifone joined with D-Link's South American subsidiary and local payments processor MediaNet. The Mall's Wi-Fi project team was able to eliminate merchants' multiple dial-up phone lines and Internet access points. Not only did this cut merchants' long-distance phone charges, but the online wireless network and systems platform provided 24-7 availability. It also improved payment processing speeds and the transfer of data to merchants' management centers by up to 350 percent, or an average four seconds per transaction. -from E-Commerce Times, June 16, 2004

requirement with only 20 MHz channels would require at least three antenna analog front ends at both the transmitter and receiver. At the same time, a 20 MHz approach will struggle to provide a robust experience with applications that demand higher throughput in real user environments.

Intel believes both MIMO technology and wider bandwidth channels will be required to reliably satisfy the higher throughput demands of consumer electronics applications. This will become increasingly true as BSS environments need to service multiple high throughput applications simultaneously, especially where servicing networking applications is also required. Choosing conservative increases in channel bandwidth, combined with conservative approaches in MIMO technology, will enable cost effective solutions that meet the high demands of these types of applications. This combined approach, employing MIMO and 40 MHz channels will enable the IEEE 802.11n technology to reach even higher performance as Moore's Law and CMOS process technology improvements advance DSP capabilities.

While data and audio transferring have been the primary attractions for most Wi-Fi users, the next hot application will be video. On the horizon is Internet movie downloading. Imagine being able to view streaming video on a notebook computer or PDA over a wireless connection. Currently, 802.11g is capable of streaming video, but quality of service issues hurt performance. The video image can be jittery and halts when the network gets overloaded.

Intel and other members of the 802.11e multimedia service specification have developed a fix. A speed enhancement called packet bursting technology increases throughput by allowing multiple packets to travel over the airwaves without the extra overhead of spaces between packets — thus increasing network speed. The 802.11e specification takes place in the MAC layer and thus it will be common to the Physical Layer (PHY) of all 802.11 WLAN technologies when it's finalized and adopted (probably in late 2004). Consequently, 802.11e packet-bursting will be available in 802.11g, b, and a.

Working in a unique Anglo-German partnership, Midas Telecom and EP Scheiba are rolling out a wireless broadband internet service in Germany, starting in the little town of Bergen, by the Luneburg Heath. "We have a pilot operation right now, reaching around 400 homes," says Joe Roper from Bristol based Midas Telecom. "Our full roll-out, which we are installing in 2004, will cover 2,000 homes. Network coverage and range has been even better than we had hoped, and we are already reaching twice the number of users that we had expected to." The Bergen Mesh delivers broadband internet service to end users over a wireless network. Each user just needs an inexpensive wireless network adapter to get on-line. The mesh carries the signal through multiple mesh nodes to the nearest internet gateway. -LocustWorld.com

Mesh networking, also known as "multi-hop" networking, is a flexible architecture for moving data efficiently between wireless devices. Mesh technology expands the reach of wireless networks by allowing signals to be passed from one wireless router to another. By placing wireless routers every few hundred feet, signals can be beamed for miles. Mesh networking is already being used to enable Wi-Fi access for entire towns in places such as Rio Rancho, New Mexico (population 60,000). Mesh networking specialists Space IP have recently installed a mesh network in Fulham, West London. Mesh networking could also be used on a smaller scale in a setting such as a home. Every radio-enabled device in a home could perform in three different roles: as a client, router, or an end point for another user. Devices could self-organize into temporary, ad hoc networks that emerge and disband in response to your needs. Mesh networking is a key aspect of ongoing efforts in both 802.11 and 802.16 (WiMAX) standards. Intel is contributing to these efforts through participation in industry groups, as well as its own research into architecture for interconnecting wireless devices of all kinds in mesh networks.

One problem with wireless has been security. Unrestricted by the physical constraints of cabling and walls, wireless LANs have proved tricky to secure. Hackers easily cracked such initial efforts as the Wired Equivalent Privacy (WEP), an early security protocol. This left some companies hesitant to adopt wireless technology for fear that the data transmitted between a wireless device and an access point could be intercepted and decrypted.

To shore up a battered security model that was slowing wireless adoption in the enterprise and making home users nervous, the Wi-Fi Alliance introduced its own interim version of the 802.11i security specification: Wi-Fi Protected Access (WPA). WPA combined several technologies to address all known 802.11 security vulnerabilities. It provided strong user-based authentication through the use of the 802.1X standard (a mutual authentication framework designed to provide controlled port access between wireless client devices, access points, and servers) and the Extensible Authentication Protocol (EAP). WPA also included robust encryption through 128-bit encryption keys and the use of the Temporal Key Integrity Protocol (TKIP). A message integrity check (MIC) prevented attackers from capturing and altering or forging data packets. This combination of technologies protected the confidentiality and integrity of WLAN transmissions while helping ensure that only authorized users gained access to the network. WPA further enhanced security and manageability by offering automatic key distribution, unique master keys for each user and each session, and unique, per-packet encryption keys.

The IEEE standard, 802.11i, ratified in June 2004 incorporates many of the features already in practice through WPA. Some 802.11i substantial changes over WPA involve better handoff and better encryption. The 802.11i standard also offers key caching to allow quick re-attachment to servers when a person returns. What's more, it provides pre-authentication for fast roaming among access points in a network.

The practical upshot of 802.11i's ratification is that the wireless market should boom again as firmware upgrades and new products enter the market. With 802.11i, the whole security chain for logging in, exchanging credentials, authenticating, and encryption becomes so much more robust and effective in protecting against both non-targeted and targeted attacks. A network and a session's integrity now just needs to be managed, not protected.

Intel is moving for immediate Wi-Fi certification of its 802.11i products. Intel® Centrino® processor technology will incorporate 802.11i. All notebooks built on Intel Centrino processor technology notebooks products will be upgradeable to 802.11i by the end of 2004.

Obviously, the wireless broadband vision of freedom from wired Internet connections is becoming a reality in many parts of the world. What's driven its success is having a standard. Like the Ethernet standard has been to networking,

"One clear lesson in the history of technology and business is that once an open standard gains critical mass, it is extremely hard to derail." -J. William Gurley, General Partner, Benchmark Capital

802.11 has been to wireless communications. The standard has been crucial to industry innovation and acceptance of 802.11 products. Because of it, customers enjoy the ability to buy 802.11 devices with assurance of the interoperability, and the Wi-Fi industry has profited from the fast growth spawned by having an open standard.

Intel is committed to 802.11 and will continue to drive the industry standards, ecosystem development and end-user awareness necessary for the broad proliferation of broadband wireless. The innovation that has led to 802.11's success will continue as wireless networking is adapted to every facet of our lives, from cars and home to office buildings and factories.