Milestone-Proposal:The birth of WiFi


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Docket #:2015-13</div> This proposal has been submitted for review.


To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s fields of interest? (e.g. “the theory and practice of electrical, electronics, communications and computer engineering, as well as computer science, the allied branches of engineering and the related arts and sciences” – from the IEEE Constitution) Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an Electrical Engineering Milestone? Yes


Year or range of years in which the achievement occurred:

1987

Title of the proposed milestone:

The birth of Wi-Fi, 1987

Plaque citation summarizing the achievement and its significance:

In November 1987, a group of Dutch engineers demonstrated the feasibility of wireless computer networking. They helped to found and lead IEEE 802.11, the Working Group for Wireless Local Area Networks. After approval of the standard, the Dutch group teamed with Apple Computer to open the general market. Apple products were among the first to carry the Wi-Fi certified product logo.

In what IEEE section(s) does it reside?

IEEE Benelux Section

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: IEEE Benelux Section
Senior Officer Name: Senior officer name masked to public

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: IEEE Benelux Section
Senior Officer Name: Senior officer name masked to public

IEEE section(s) monitoring the plaque(s):

IEEE Section: IEEE Benelux Section
IEEE Section Chair name: Section chair name masked to public

Milestone proposer(s):

Proposer name: Proposer's name masked to public
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates of the intended milestone plaque site(s):

Stadsplein 1, 3431 LZ, Nieuwegein GPS coordinates: x 134.280 y 488.890

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The intended site is a building where various organizations are housed (municipality of Nieuwegein, a library, social service and social welfare). Therefore it is called ‘Stadshuis’ (= city house). It is the closest public accessible building from where Wi-Fi was originally developed (an office building approximately 600 m away).

Are the original buildings extant?

Yes

Details of the plaque mounting:

The intended location is in the central entrance hall of the building. A picture giving an overview of the entrance hall of the town hall is shown below. The IEEE can consult the municipality of Nieuwegein about the exact place and mounting within the hall.


Nieuwegein hal.jpg

How is the site protected/secured, and in what ways is it accessible to the public?

The building is opened on weekdays and Saturdays. The site is protected/secured by a security company and security cameras.

Who is the present owner of the site(s)?

Municipality of Nieuwegein

What is the historical significance of the work (its technological, scientific, or social importance)?

In essence, Wi-Fi has brought wireless connectivity at high data rates with Internet or Intranet at affordable prices. The Wi-Fi devices are now carried in all handheld devices, from laptops to tablets, printers and mobile phones. It provides fast and efficient, wireless, connection to the Internet at companies, hotels, stations, restaurants, shops, public buildings, residences, in trains and even in airplanes etc. It is very easy to deploy a Wi-Fi network within a meeting room and connect all attendees to the Internet or local servers to disseminate meeting documentation. This technology brings ease of access to information supporting both the workforce as well as the crowd seeking entertainment. Scientifically, Wi-Fi has been pioneering the application of direct sequence spread spectrum at its top capabilityi, was the first in applying Orthogonal Frequency Division Multiplexing (OFDM)ii in packet networks over radio links and was the first application of spatial diversityiii with two and four spatial streams in the same channel. Telecom providers are using Wi-Fi to off-load their cellular networks. Modern devices like smartphones and tablets have increased data transfer needs to values beyond the capacity of their cellular network. Thanks to Wi-Fi via hotspots or via private cable and telephone networks, they were able to offload traffic from their cellular network and continue serving their customers satisfactorily [1] and [2]. In rural areas, Wi-Fi brings economic and social benefits to the inhabitants. Modified versions of the Wi-Fi devices enable Internet connectivity in these areas where incumbent telecommunication providers cannot or will not deploy their networks and community initiatives have deployed many Wi-Fi networks, bringing social contacts, increased economy and medical assistance to the inhabitants, otherwise deprived from Internet and telephony contact.

What obstacles (technical, political, geographic) needed to be overcome?

Wireless data transfer rate too low

Early in the investigation of the technology, it was understood that a transparent user experience was required. At that time, office and business communication systems using wired Local Area Network technology carried data rates exceeding 1 megabit per second. No commercial wireless technology was available that approached that speed barrier. To reach that goal, sufficient radio bandwidth was needed that was easily accessible. In 1985 the spectrum regulator for public services in the US, the Federal Communications Commission (FCC), permitted the use for communications, in three bands, without requiring an end-user license for the use of a radio transmitter (ease of access), provided the radio used “spread spectrum”. With spread spectrum, the data is transmitted over a larger amount of bandwidth then needed, either by multiplying the data with a pseudo-random codeiv (dubbed direct sequence spread spectrum), or by changing the centre frequency in a pseudo random pattern (dubbed frequency hopping spread spectrum). The spectrum was provided at frequencies close to or above 1 GHz. The characteristics of the radio waves at that frequency in general, but especially its indoor characteristics, were unknown. Propagation measurements needed to be done. Silicon circuitsv were only available in commercially viable prices for the lowest of the three bandsvi so that was the band to use in the 1985-1995 timeframe. Unfortunately only 26 MHz of spectrum was available. Frequency hopping could only use a bandwidth of 25 kHz, limiting the maximum data rates to 25 kilobit per second. Direct sequence had no upper bandwidth limit, but the band itself limited the bandwidth to 26 MHz. However, the spreading requirement lowered the maximum bitrate proportionally because the transmitted data is to be multiplied by a pseudo-random code. The elements of the code are called chips. The FCC did not state a minimum number of chips. The general feeling was that 125 or 255 chips was required. However, even with a 100 chip pseudo-random code the 230 kilobit per second transfer rate was not sufficient for the application on hand. An eleven chip pseudo-random code, a so called Barker sequence, with superior properties was available. The question was, however, whether the FCC would permit pseudo-random code of 11 chips. A visit to the offices of the FCC taught that a 10 chips was the minimum.vii With the knowledge that the FCC would approve the length, the code was adopted and a 2 megabit per second data rate was achieved. This led to approval by the FCC for devices supporting a maximum data transfer rate of 2 megabit per second. As shown in Figure 1,viii it was an 8-fold increase over other products and it was applied in the WaveLAN product (Figure 2) released in 1990 (see chapter “References to establish dates etc.”). The same fundamental wireless modulation technique was adopted in the first IEEE 802.11 Wireless LAN standard and Wi-Fi.

Figure 1. Early FCC approvals for Spread Spectrum devices
Figure 2. First production device

Radio environment is difficult to control

In a license-exempt radio band, the users have to share the frequencies, both among similar devices as well as to devices using different protocols. To orderly use and share the radio channel a method of listen-before-talk is used, called carrier sense multiple access (CSMA). Before a station transmits it verifies at its receiver whether no other station is transmitting. There is a probability that two stations have established that the channel is free and start transmitting. In a cabled environment, the receiver of a transmitting station is able to detect such event. They both defer transmission by sending a jam signal to prevent stations to use the erred transmission. This method is called carrier sense multiple access with collision detection (CSMA/CD). In a radio environment, however, the signals attenuate quickly along the path they travel. In the wired medium, the attenuation is around 1000 times over 10 m, radio signals in free space at 2.4 GHz attenuate 10,000 times in the first meter, 1,000,000 in the first 11 meter. A transmitting wireless station cannot detect the signal of any other receiver because they are too weak. So neither transmitter sending at the same time can detect the collision and their transmissions are lost. To overcome subsequent collisions, stations that have detected a busy channel and defer transmission, have to wait a randomly selected back-off time after the channel becomes free, and decrement the back-off time while the channel is free. When the back-off time decrements to zero it will start its transmission. This way the waiting station for transmission with the smallest time set, starts transmission and other stations defer until the channel is free again and decrement the remainder of their back-off time while the channel is free again. This medium access protocol is called carrier sense multiple access with collision avoidance (CSMA/CA).

Setting an industry standard

July 1990 a new Working Group for setting a standard for Wireless Local Area Networks was established. The designation of the working group is IEEE 802.11, Standards Working Group for Wireless Local Area Networks. In 1997 the first standard, IEEE Std 802.11 was published. It provided 3 methods for the propagation of signals. The first one was through Infra-red. Unfortunately, no implementations have been brought to market. The second one was through frequency hopping spread spectrum radio carrying a maximum of 1 megabit per second, and the third one was through direct sequence spread spectrum radio carrying a maximum of 2 megabit per second. Both were for the 2.4 GHz band. The latter is still mandatory in any 2.4 GHz band implementation. To comply with the necessary capacity and market requirements for higher data rates, the working group produced two extensions to the standard. IEEE 802.11a for 54 megabit per second in the 5 GHz band and IEEE 802.11b for 11 megabit per second in the 2.4 GHz band. Later developments increased the transfer rates to 6.750 gigabit per second.

Interoperability across products

To overcome confusion in the marketplace, ease of connectivity to the users through a standard and a certification program was required. During the 1990s various companies provided proprietary products to the market. Users purchased devices from one vendor and were annoyed when they purchased additional equipment from another vendor to find out that there was no connectivity, or when visitors could not connect at their premise because it had equipment from another brand. Key to the success of Wi-Fi are the efforts by many individuals in the IEEE 802.11 working group and the Wi-Fi Alliance. IEEE 802.11 produced the interoperability standard that was set by many individuals in a process of reaching consensus by group decisions on their submissions in long debates, through tedious resolving comments supplied in ballots as well as the efforts of officers leading the various groups and the editors of draft standards. In addition to the interoperability specification of IEEE 802.11, buyers needed to know which product would interoperate with other products. The solution was reached by the industry alliance WECA, later renamed into Wi-Fi Alliance. They selected key elements which products needed to have minimally and performed a certification test on new products. Products that passed the test were allowed to carry the certification logo showing the letters Wi and Fi on each product.

Radio spectrum extension

Politically and regionally the availability of sufficient radio spectrum with compatible rules in all countries of the world was a required asset. Efforts by members of the standards working group and of the various vendors brought the 2.4 GHz radio spectrum. Efforts by members of the Wi-Fi Alliance, regulators from various countries and members of the standards working group brought a World Radio Conference 2003 Resolution for the 5 GHz radio spectrum that had to be followed by all countries. In 2015 the maximum data transfer rate offered in the IEEE 802.11 standard is 1.3 gigabit per second in the 5 GHz band to a mobile station. However, an access point can handle a number of mobile stations leading to an aggregate data transfer rate of 3.9 gigabit per second with the IEEE 802.11 ac extension. In addition, 6.750 gigabit per second data transfer rates is offered over short links in the 60 GHz band with the IEEE 802.11ad extension.

What features set this work apart from similar achievements?

In the 1990 to 1999 timeframe, cellular networks are based on voice connections with some data traffic at low transfer rates, use a centralised protocol in a large coverage area and use licensed spectrum. Usage is therefore costly because the service provider must pay for the, private, use of the spectrum in specific areas. To cover the area of up to 6 km2, the transmitters emit power up to 2 or 10 Watt. When more people want to use the network beyond its capacity, users are denied service (busy tone). Wi-Fi is based on high speed connectivity with a distributed protocol in smaller geographic areas and using license-exempt spectrum. Because of the smaller geographic area used, the transmitters emit lower power (up to 50 mW) than transmitters in cellular networks. Hence the signals are only detectable within the smaller area and the spectrum can be reused in an adjacent geographic area. Voice connections can be made on top of the Internet protocol. Whereas cellular networks deny further service requests when the capacity is fully used, Wi-Fi networks distributes the capacity among all users, so that users continue to be connected, though the transfer rate is reduced. The use of the spectrum is free of charge, the protocol is decentralised and can be used anywhere.

References to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article.

The setting of an industry standard as well as the establishment of the certification program and marketing effort by the Wi-Fi Alliance are processes of reaching consensus by group decisions and contributions by many individuals. However, the role of the Netherlands in the success of Wi-Fi is worth to recognize their efforts. It started with the initiatives and work of a small team referred to as the WaveLAN team. They co-founded and led the standards working group and contributed key technical proposals as well as their experiences learned from their products in the field. Their daring move to release a product with 11 Mbit/s for less than $ 100.- at the moment where the price point in the market was $ 300.—for products with 2 Mbit/s caused competitors working on HomeRF and HIPERLAN to discontinue their product development, paving the way for the breakthrough of Wi-Fi. Subsequently the Airgo and No-Wires-Needed teams, both in the Netherlands, added their efforts to sustain a chain of improvements.

The WaveLAN-team

The initiative leading to the development of wireless LAN products, the development of the IEEE 802.11 standard and the co-establishment of the Wi-Fi Alliance was taken at an Engineering Laboratory operating in Utrecht the Netherlands. In 1985 it was part of NCR Corporation. Further reference to the laboratory will be WaveLAN-team. Throughout its existence the WaveLAN-team operated under various corporate names. In 1991 NCR was acquired by AT&T, in 1996 AT&T split into three parts and the corporate name changed into Lucent Technologies. In 2001 Lucent Technologies sold some of their business units and the corporate name was changed into Agere Systems. Interesting to know is that Bell Labs collocated a department in the same building in 1994. Their charter was to do research in the same subjects as done by the WaveLAN-team.

In the mid-nineteen eighties NCR, a US based company specialising in terminals for financial and retail institutions and small to mid-size computers, had the objectives to suit the wish of their retail customers to connect their terminals, cash registers, without cables to the back-office computer, so they did not need to drill new holes in their marble floors after changes in the floorplan.

Experiments to connect through Infra-red links turned out to be tedious because the need to align transmitters and receivers and it limited the possibility of their customers to hang banners and other ornamentation in the shops. When the FCC permitted the use of spectrum without the need for an end-user license, NCR wanted to pursue this opportunity to resolve the cash register issue and assigned the request for an investigation into the feasibility of a radio link for retail terminals. They found the best skills to do an investigation at the WaveLAN-team. In addition to the engineers, the WaveLAN-team also operated with a team of product managers, responsible for the acquisition of funding, the marketing and the product lifecycle management.

November 1987 the WaveLAN-team demonstrated the feasibility of a 100 kilobit per second radio link between two PCs to a review team of NCR Headquarters and people from the Retail Division of NCR, “customer” of the development work (Figure 3). The first prototype (Figure 4) was equipped with a surface acoustic wave (SAW) filterx (Figure 5 ) in the receiver to recover the data from the transmitted signal which was modulated by a direct sequence spread spectrum code.

Figure 3. Status report mentioning the first demo
Figure 4. First prototype
Figure 5. SAW filter

August 1988 the WaveLAN-team demonstrated a 200 kilobit per second prototype (Figure 6 and Figure 7). The cash registers were IBM compatible PC’s with special devices such as the display, the keyboard, the barcode reader and the receipt printer. The registers were not equipped with a hard disk. All information such as article name and price had to be communicated from the in-store processor. In the morning, when the cashiers started, the programs for all registers had to be uploaded from the in-store processor. Hence the need of data transfer rates of at least 1 megabit per second.

Figure 6. Status report mentioning the second demonstration
Figure 7. Second prototype

In search of a shorter than 125 chip code, one of the engineers at the WaveLAN-team used a small programmable calculator to investigate properties of shorter codes. When he entered a certain code of 11 chips, calculations showed that the properties were excellent. This is the code the FCC accepted. The WaveLAN-team decided to use the code for their developments.

For the first release of the product, a simple and cost effective method was used by applying an off-the-shelf CSMA/CDxi controller chip. Many of the functions necessary to interact between the computer memory and the link were available in the chip. A patented method as described in US patent no 5,369,639 [3] is used to mimic the CSMA/CAxii control, yet using a CSMA/CD chip. The first public demonstration was given at Networld 90, Dallas (TX). It stirred the press [4]. Earlier in time, the WaveLAN-team was convinced that an industry standard for wireless communications among computers was important for acceptance by the users in the IT Industry. Hence the initiative to participate in a task group in the IEEE 802 project (Local and Metropolitan Networks Standards Committee) that already had a project approval for a wireless extension to the Token Bus Standards, IEEE 802.4. However, the members of the task group had already given up and the task group was inactive, so it was necessary to take the leadership in 1988. In 1989 the WaveLAN-team proposed the 11 chip pseudo-random code to the task group [5]. Mid 1990 the task group concluded that the IEEE 802.4 protocol was not suited to be used in a radio environment, hence in July 1990 they generated the paperwork to start a new Working Group for a Wireless Local Area Network. The establishment of the working group was approved by the members of working group 802.4 and was put on the floor of the IEEE 802 Executive Committee at their closing meeting of the penary meeting. Following their approval, the first meeting was held in September 1990, chaired by an employee of the WaveLAN-team. Recognising that the resulting standards are made as result of group decisions, the WaveLAN-team provided the leadership. First by providing the chairman, and subsequently the technology both in submissions as well as know-how stemming from its experience with its product. The WaveLAN-team also proposed the direct sequence modem as used in its existing product [12]. that was taken as the base for the template of the parameters of the PHY part of the standard [13].

Higher layer networking provisions

In addition the WaveLAN-team presented the following elements towards the standard:

  • the architecture of a wireless area with a Basic Service Area (BSA) around an accesspoint and an Extended Service Area (ESA) for a group of accesspoints belonging to the same domain and connected via a distribution system [6],
  • a comparison of CSMA/CA characteristics including an immediate ACKxiii and the CSMA/CA as known since 1978 and implemented in the WaveLAN-team’s existing product [7]. The ACKis essential for significant improvement of the reliability as it allows for rapid recovery from failed transmissions,
  • a method of supporting time-bounded services like voice, video and process control systems and direct station-to-station communication (without use of an accesspoint) [8],
  • power management provisions to improve battery life in mobile applications [9] and
  • the joint wireless MAC proposal with Symbol Technologies [9]

Eventually a joint proposal was submitted by the WaveLAN-team, Symbol Technologies and XIRCOM and was called the Distributed Foundation Wireless MAC, the DFWMAC [10]. It was elected as the base for standard [1].

To allow wireless stations to operate throughout larger areas covered by multiple “overlapping” access points, concepts and algorithms were developed for mobile stations to detect access points, determine the quality of their connectivity and initiate timely handover to maintain active communications.

The mobility aspects of the wireless network connection also created new phenomena in the cabled network infrastructure. During active communications a station could now all of a sudden move into and re-connect to a different segment of the network. This could be a different segment of the same LAN, or a different subnet of a network, or even a completely different network. For the user this should all work seamlessly of course. So, link and higher layer protocols had to be developed to re-establish network connections “on the fly”. Bridge filtering tables had to be updated dynamically [11]. For this, inputs were provided to the 802.11c Bridging supplement for the IEEE 802.1D Bridging standard, and a proposal was made to the Internet engineering task force (IETF) for an Inter-Access Point Protocol to standardize the way access points would inform intermediate bridges about the new location of a mobile station. To address the network routing issues, different approaches were initiated and supported. Within the IETF a working group developed Mobile IP to maintain TCP/IP connections by re-routing and tunnelling IP packets. With network providers like Novell and Microsoft the WaveLAN-team initiated developments to re-establish transport connections upon a handover.

Mid 1997 the standard was ratified by the standards board of the IEEE and two new projects were proposed for further extension of the data transfer rate.

Figure 8. IEEE 802.11 compliant product 1997

With such short codes and with the advancement in the digital signal processors technology, SAW filters were not necessary anymore and further developments were implemented with digital signal processors. The first production device (Figure 2), called NCR WaveLAN, was released at the end of 1990 and available in quantities in 1991.

Soon after approval of the standard, the WaveLAN-team released a product compatible to the standard (Figure 8). Market research revealed that the data rate of 2 megabit per second did not impress because the cabled LANs were in the process of moving from 10 megabit per second to 100 megabit per second. All participants of working group 802.11 were motivated to work on higher data rates and two projects were requested for and approved by the IEEE Standards Board. The WaveLAN-team submitted two proposals to those projects. One was for the 5 GHz band [15] which used orthogonal frequency division modulation (OFDM) for up to 54 megabit per second transfer rates. The proposal was adopted as the base for project IEEE 802.11a (Higher Speed PHY Extension in the 5GHz Band). The second proposal was for the 2.4 GHz band [14] and used Barker code position modulation (BPM) yielding 4 and 8 megabit per second transfer rates, the maximum transfer rate possible with the FCC rules. However, lawyers of Harris had found a way to conform to the FCC rules with codes shorter than 11 chips and submitted a proposal. One of the WaveLAN-team engineers knew how to improve the coding and Harris and Lucent agreed to make a joint proposal resulting in acceptance by the working group. The modulation is called Complementary Code Keying (CCK) [16]. The new proposal was adopted for project IEEE 802.11b (Higher Speed PHY Extension in the 2.4 GHz Band).

In 1999 two extensions for the standard were published. IEEE 802.11a for a maximum of 54 megabit per second in the 5 GHz band and IEEE 802.11b for a maximum of 11 megabit per second in the 2.4 GHz band.

With a standard in place, Steve Jobs of Apple Computer decided to add wireless communications to the MAC books. He requested proposals from the various vendors. All were happy to oblige, but just one accepted the challenge of the $100 retail price requirement when the price point was still at around $600. It was the management of the WaveLAN-team that took the challenge and prepared a manufacturing environment streamlined to produce large quantities at low cost. At the MACWorld on July 21st, 1999, Apple Airport was launched [17] with the PC card (Figure 9) at $99 and the access point at $299 (Figure 10). At the same time, the WaveLAN-team, now with the corporate name of Lucent Technologies, launched their own PC card (Figure 11) and access point for similar prices. Immediately, all PC vendors queued at the engineering group with the request to develop a version for their own market.

Figure 9. Client Card Apple Airport
Figure 10. Access Point Apple Airport
Figure 11. Lucent Technologies’ Client Card

The WaveLAN-team was among the founders of Wireless Ethernet Compatibility Alliance (WECA). In 2000 the devices of the WaveLAN-team were among the first certified products with the Wi-Fi logo (see on the card in Figure 11) as shown in an announcement “Wireless Ethernet Compatibility Alliance (WECA) Awards First Wi-Fi Interoperability Certifications” [18]

With successful commercial launch, attractive price point driven by Apple and Wireless LANs integrated in the Apple Operating System, Microsoft invited the WaveLAN-team to participate in the integration into Windows XP. The Access Point search function and the now well recognised “green level logo” (Figure 12) are legacy from the WaveLAN-team’s system. This further brought the technology into the mainstream for explosive growth.

Figure 12. “Green” level logo

Already during the development of the base standard a Distributed Control Function (DCF) priority mechanism was presented by The WaveLAN-team [19]. Later during the development of the Quality Of Service (QoS) Standard in Task group E this priority mechanism and associated architecture changes were proposed and adopted in cooperation with The No-Wires-Needed-team (then part of Intersil) as part of the 2005 standard supporting QoS.

In 2004 the parent company of the WaveLAN-team, Agere Systems, decided to withdraw from the Wireless LAN market and the WaveLAN-team was terminated.

More people in the Netherlands contributed to the success of Wi-Fi.

No Wires Needed

Nine students at the University of Twente in the Netherlands founded the company called No Wires Needed B.V. in 1994. The company focused on WLAN and bridge technology. With the WEP protocol of the first standard considered too weak they developed their own cryptography Airlock in 1998. In 2000 Intersil acquired the company for $90M in shares [20].

From 1996 they participated in the work of IEEE 802.11 and continued to do so after the acquisition by Intersil. To project IEEE 802.11e (Quality of Service) they introduced the enhanced distributed coordination function (EDCF) with the important breakthroughs of multiple internal (virtual) DCFs that realize the distributed scheduling of transmit opportunities with different priorities and of differentiating maximum transmission length per traffic class as described in IEEE 802.11 submission "A simpler and better EDCF" [21]. They worked together with The WaveLAN-team to combine it with the priority access mechanism in the DCF. Other contributions on 11e include “Enhance D-QoS through Virtual DCF” [22]“DCF Proposed Draft Text” [23], two on “Distributed Admission Control for EDCF” [24]and “Proposed Normative Text for EDCA” [25] .

They contributed to the co-existence of Orthogonal Frequency Division Multiplexing (OFDM) and CCK modulations in project IEEE 802.111g (Further Higher Data Rate Extension in the 2.4 GHz Band). For the first time the mechanism of co-existence is defined in "Why the TGg compromise will work" [26] and "802.11g MAC Analysis and recommendations" [27], laying the foundation for Wi-Fi evolution in the same spectrum (11b and 11g in this case, but conceptually applying to 802.11n and beyond) plus the optimised MAC parameters for this to work. EE Times published a page “Overcoming IEEE 802.11g's Interoperability Hurdles”[28].

They also contributed to security in project IEEE 802.11i (MAC Security Enhancements), by enabling the evolution from the insecure WEP standard to WPA on the same hardware. i.e. without abandoning the installed base. This includes the introduction of TKIP/Michael in “'Michael: an improved MIC for 802.11 WEP” [29], “'TKIP with 48-bit Ivs” [30] and “Alternate Temporal Key Hash” [31]. For the state-of-the-art privacy in Wi-Fi called WPA2, they introduced AES-CCM in “AES Mode Choices - OCB vs. Counter Mode with CBC-MAC” [32] and “AES Encryption & Authentication Using CTR Mode & CBC-MAC” [33], which has also been adopted outside W-Fi including TLS, IPsec, NIST and ZigBee.

July 2003, Intersil sold the Network department to Globespan Virata, and in 2005 Conexant acquires Globespan Virata. July 2005 Conexant transferred the activities of the Dutch facility to India and the operation of the No-Wires-Needed-team was terminated.

The Airgo-team

The first Bell Labs operation outside the United States was co-located at the facility of the WaveLAN-team, focussing on Wireless LAN’s. They contributed to the work of IEEE 802.11a and 11b. In fact their proposal for project IEEE 802.11a (OFDM), i.e. “OFDM Physical Layer Specification for the 5 GHz Band” [15] was selected as the foundation of the extension of the standard. The proposal for project IEEE 802.11b (Barker-Position-Modulation) was the result of Bell Labs research “Draft text for the Higher Speed Extension of the standard” [14]. Van Nee saw that the Intersil proposal could be improved with the CCK method he published in a paper at IEEE Globecom 96 [34]. The Dutch engineering team, Bell Labs and Intersil joint forces and the resulting proposal was selected by the Working Group “Introducing the Harris-Lucent Compromise Proposal for TGb” [35] and “Harris/Lucent TGb compromise CCK 11 Mbps proposal – Selection criteria” [16].

In 2001, the key engineers of Bell Labs founded, together with people from Cisco, the company Woodside Networks, later changed into Airgo, with a facility in Breukelen, the Netherlands, and referred to as the Airgo-team. The same year their US colleague presented spatial diversity and spatial multiplexing as the solution for higher data rates to the “Wireless Next Generation” standing committee [36]. Their engineers built the first Multiple Input-Multiple Output (MIMO)-OFDM Wireless LAN product, published a paper at a conference in San Francisco [37] and one in Wireless Personal Communications [38] and a book chapter in the “Emerging Technologies in Wireless LANs” [39]. To project IEEE 802.11n (High Throughput) they contributed the “Joint Proposal MAC Report” among many co-authors [40], “Joint Proposal: High throughput extension to the 802.11 Standard: MAC” [41]and “LB97 CID 1945 Dual CTS” [42]. Eventually, in 2009, the standard project IEEE 802.11n (High Throughput) , based on MIMO-OFDM was ratified by the IEEE Standards Board.

Airgo was acquired by Qualcomm in 2006. Dutch engineers continued their excellence in the next higher data rate extension Taskgroup 802.11ac (Very High Throughput 6 GHz) where an engineer of the Airgo-team had the honour to present the first draft specification on behalf of a large group of co-authors “Strawmodel 802.11ac Specification Framework” [43]. He published a paper in the IEEE Wireless Communications Magazine titled “Breaking the gigabit per second barrier with IEEE 802.11ac” [44].

To Project 802.11z (Direct Link Setup) the Airgo-team contributed “Tunneled Direct Link Setup (TDLS) with Channel Switching” [45], “Speculative TGz Draft 0.3” [46] and “Peer Power Save Mode for TDLS and Peer Power Save Mode for TDLS” [47].

To Project 802.11ah (Sub 1 GHz) the Airgo-team contributed “Proposed TGah Draft Amendment” [48].) and to Project 802.11ax (High Efficiency WLAN) “Proposed Specification Framework for Tgax” [49].

To date the Airgo-team is still in business.

Current status of Wi-Fi

Nowadays the impact of Wi-Fi on society, both socially and economically, can hardly be overestimated, as follows from the following figures published by the Wi-Fi Alliance September 2014:

At the core of market growth

Today, Wi-Fi is in broad use in homes, enterprises, public spaces and hotspots. Fifteen years since its origin, the numbers are testament to the technology’s value:

  • More than 22,000 products have been Wi-Fi CERTIFIED, including more than 4,000 phones and tablets, 6,000 access points, 1,100 printers, and 3,500 televisionsix, xiv
  • Consumer demand for Wi-Fi has continued to grow, with sales figures of about two billion Wi-Fi devices sold in 2013 alone and a forecast exceeding four billion in 2020ii, xv
  • Wi-Fi is used in 25 percent of homes around the world xvi

Information

More information on the innovation journey of Wi-Fi is available in a book on the history of Wi-Fi [50].

References

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Notes

i. The original standard IEEE 802.11 carried the maximum transfer data rate of 2 megabit per second in 1997, later improved by extension 11b to the standard to 11 megabit per second in 1999.

ii. In OFDM the data is not modulated on a single carrier, but is cut in slices, where each slice is modulated on separate sub-carriers. By adding “forward error correction” information, the receiver is able to reconstruct the data when a number of carriers were lost due to echo’s cancelling out certain frequencies.

iii. In analogue radio, transmission of two signals on the same channel or frequency would cause the two signals to interfere. The result is that the signal cannot be reliably recovered; for instance when two devices in the citizen’s band transmit at the same time in the same channel, the receivers produce a whistle sound. With indoor digital transmission using OFDM, the interference of two (or more) output devices, on the same channel but each carrying a part of the data, causes the signals to vary in amplitude depending on the pattern of reflected rays as a function of the used frequency and the place of the two (or more) input devices. The successfully received subcarriers can so be merged to original data.

iv. The pseudo-random code is a sequence of +1 and -1 values called “chips”. The more chips the larger the spreading and the lower the power spectral density. With 255 chips the power spectral density is so low that the signal can hardly be shown on a power display device and looks like noise. However, in a 20 MHz wide channel, as used in the subject standards, the bitrate would be in the order of magnitude of 150 kilobit per second.

v. The cellular industry was starting up in the 700-1,000 MHz, so sufficient demand for silicon circuitry caused the price to go down

vi. The three bands were 902-926 MHz, 2,700-2,783.5 MHz and 5,725-5,850 MHz.

vii. In an order in 1990 the FCC published the minimum processing gain to be 10 dB. The interpretation at that time was that a pseudo-random code of 11 chips was the minimum.

viii. The FCC maintains a database with equipment they approved. See https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm , fill in the fields for “Final actions date range” with 01/01/1986 and 01/01/1991, select “DSS-Part 15 Spread Spectrum transmitter” in the field for “Equipment class” and 30 in Show … Records at a Time (HTML output only). The data rates are taken from the article from Byteweek in referenced document [4].

ix. In 1999 some Wireless LAN equipment manufacturers established the Wireless Ethernet Compatibility Alliance (WECA) to combat the confusion on the market caused by many incompatible wireless LAN products. They established a certification program for products conforming the IEEE 802.11 standard and introduced the Wi-Fi Logo. In 2002 they changed the name into Wi-Fi Alliance.

x. A SAW filter is using the piezo-electric characteristics of a silicon chip. The pulses from the received signal are mechanically applied to the silicon at one side of the silicon chip. The pulses propagate, “travel” so to say, as a wave through the chip, causing electrical activity alongside the way. By applying connected taps alongside the travel route at distances according to the pseudo-random code, the yield of the collection of taps would be at a peak when the pseudo-random code is completely shifted onto the chip. In the case of the eleven chip pseudo-random code, the output is plus or minus eleven units at that time, while at other times the output is zero, plus or minus 1.

xi. CSMA/CD, Carrier Sense Multiple Access with Collision detection, is used in the IEEE 802.3 or Ethernet Local Area Networks where the transfer medium is using cables. Before a station transmits, it checks whether its receiver senses transmission by another station. In the rare case that two stations start transmitting at the same time, the two receivers can detect that there is another station transmitting at the same time because in the cabled medium the attenuation of the signals is within a factor ten; sufficient for the technology to detect the collision. When a station has deferred transmission because it detected a carrier, it starts transmission as soon as no carrier is sensed anymore.

However, on a radio medium, the attenuation can be up to a factor of a billion (ten to the power of 9) making it impossible to detect a collision.

xii. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is used in the radio environment of the standard IEEE 802.11 to control the proper use of the ether to minimise the risk of collisions. Stations also start transmission after it has sensed no carrier from other stations. If, however, a carrier is sensed, the station apples the collision avoidance by selecting a random time delay. At the end of the time the carrier is sensed it continues to monitor for absence of a carrier for the selected time before transmission. If it senses a carrier it reapplies the collision avoidance and reselects a random time delay. An acknowledgement is transmitted immediately after successful receipt. When a station has not received an acknowledgement to a transmission, it schedules a retransmission.

xiii. The protocol requires the receiving station to send immediately an acknowledgement (ACK) after correctly receiving an Information frame. If the transmitting station does not receive the ACK it has to retransmit the frame later.

xiv. Source: Wi-Fi Alliance, 2014

xv. Source: ABI Research, 2014

xvi. Source: Strategy Analytics, 2012

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