THE WI-FI SAGA

1. Wi-Fi Introduction

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Wi-Fi is a?wireless?networking technology that uses radio waves to provide wireless high-speed?Internet?access. Although the Wi-Fi moniker was inspired by "hi-fi" (high fidelity), the name does not mean "wireless fidelity". Wi-Fi is a trademarked phrase that refers to IEEE?802.11x?standards.

Wi-Fi originated in Hawaii in 1971, where a wireless UHF packet?network?called ALOHAnet was used to connect the islands. Later protocols developed in 1991 by NCR and AT&T called WaveLAN became the precursor to the IEEE 802.11 standards.

The?Wi-Fi Alliance?was formed in 1999 and currently owns the Wi-Fi registered trademark. It specifically defines Wi-Fi as any “wireless local area network (WLAN)?products that are based on the?Institute of Electrical and Electronics Engineers’ (IEEE)?802.11 standards.”

Initially, Wi-Fi was used in place of only the 2.4GHz 802.11b standard, however the Wi-Fi Alliance has expanded the generic use of the Wi-Fi term to include any type of network or WLAN product based on any of the 802.11 standards, including 802.11b, 802.11a, etc. to stop confusion about wireless LAN?interoperability.

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2. How does Wi-Fi work?

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Wi-Fi networks have no physical wired connection between sender and receiver. Instead, they function by using?radio frequency (RF)?technology a frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then can propagate through space.

The cornerstone of any wireless network is an?access point (AP). The primary job of an access point is to broadcast a wireless signal that computers can detect and use to establish a connection to the network. In order to connect to an access point and join a wireless network, computers and devices must be equipped with wireless network adapters.

The standard wireless local area network (WLAN) technology for connecting computers and myriad electronic devices to each other and to the Internet. Wi-Fi is the wireless version of a wired Ethernet network, and it is commonly deployed alongside it.

Every laptop, tablet and smartphone come with Wi-Fi, as well as most security cameras and home theatre devices. Printers and scanners may also support Wi-Fi, and home appliances increasingly use it for control and notifications.

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3. Wi-Fi Standard

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The Wi-Fi standards. IEEE 802.11 standards cover every version of Wi-Fi, and the Wi-Fi Alliance, certifies products. Wi-Fi is the wireless counterpart to "wired" Ethernet, and Wi-Fi and Ethernet co-exist in every home and business. All versions of 802.11 use OFDM encoding except for 802.11b, which uses DSSS.

Wi-Fi operates in 2 modes – Infrastructure Mode and Ad Hoc Mode. In "infrastructure" mode, Wi-Fi devices transmit to an "access point" (base station), which may be a stand-alone unit or built into a wireless router. In "ad hoc" mode, two devices communicate peer-to-peer without an access point in between.

Throughput of Wi-Fi is proportional to the Speed which is distance dependent. The farther away the device from the base station, the lower the speed. Also, the actual throughput is generally half of the rated speed because 802.11 uses collision "avoidance" rather than Ethernet's collision "detection" method. For example, a 600 Mbps rating may yield 300 Mbps or less in real data throughput. For more about Wi-Fi networks.

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4. Wi-Fi Generations

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Following is a summary of the IEEE 802.11 Wi-Fi standards, from newest to oldest. If devices with different versions communicate, the transmission will be at the highest common speed between them.

The Wi-Fi Alliance began a new branding with 802.11ax. Called "Wi-Fi 6," previous versions retroactively became 1 to 5.

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4.1. Original Spec (1997)

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The original 802.11 specification included two spread spectrum methods in the unlicensed 2.4 GHz band: 1 Mbps frequency hopping (FHSS) and 1 and 2 Mbps direct sequence (DSSS). It also included an infrared method. Both FHSS and infrared were dropped by the Wi-Fi Alliance, but 1 Mbps DSSS method is still used by access points to advertise themselves.

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4.2. Wi-Fi 1: Slow Speed [IEEE 802.11b (1999)]

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Using DSSS and the 2.4 GHz band, 802.11b boosted speed to 11 Mbps while retaining the slower DSSS modes to accommodate weak signals. It was the first major wireless local network standard, and many laptops were retrofitted with 11b network adapters. Later, 11b was built into the laptop motherboard.

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4.3. Wi-Fi 2: Medium Speed [IEEE 802.11a (1999)]

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Using orthogonal FDM (OFDM), 802.11a transmits up to 54 Mbps. It uses the 5 GHz band and is not compatible with 11b.

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4.4. Wi-Fi 3: Medium Speed [IEEE 802.11g (2003)]

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Using orthogonal FDM (OFDM) transmission, 802.11g increased speed in the 2.4 GHz band to 54 Mbps. Both 11b and 11g are compatible, and equipment is often designated as 802.11b/g.

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4.5. Wi-Fi 4: High Speed [IEEE 802.11n (2009)]

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802.11n uses multiple antennas for speeds up to 450 Mbps. 11n operates in both 2.4 GHz and 5 GHz spectrum bands and is compatible with previous 11b/g and 11a standards. More than enough speed for the casual user.

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4.6. Wi-Fi 5: High Speed [IEEE 802.11ac (2012)]

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802.11ac operates in the 5 GHz band with data rates into the gigabit range. Very valuable when multiple users are online at the same time.

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4.7. Wi-Fi 6: Highest Speed [IEEE 802.11ax (2021)]

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802.11ax, branded as "Wi-Fi 6," operates in the 2.4 GHz and 5 GHz bands with data rates in the multi-gigabit range. More multiuser modes support higher user density. Wi-Fi 6E (Extended) adds the 6 Ghz band.

The latest Wi-Fi generation, which is the Wi-Fi Alliance branding of the 802.11ax standard from the IEEE. Emerging in 2021, Wi-Fi 6 works more efficiently in crowded networks, and it uses the same channel bandwidths as Wi-Fi 5 but with more subdivisions. However, unlike Wi-Fi 5, which operates in only the 5 GHz frequency band, Wi-Fi 6 supports both 2.4 GHz and 5 GHz. Earlier Wi-Fi devices can detect and bypass Wi-Fi 6 packets.

Wi-Fi 6 uses 1024QAM modulation (four times Wi-Fi 5's 256QAM) as well as two multiuser uplink and downlink transmission methods (MU-MIMO and OFDMA). Wi-Fi 6's theoretical maximum speed is 9.6 Gbps compared to 3.5 Gbps for Wi-Fi 5 (802.11ac). In practice, download speeds are much lower than the maximum.

Whereas previous Wi-Fi standards support one uplink stream at a time from a client to an access point (AP), Wi-Fi 6 handles several users simultaneously.

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4.8. Wi-Fi 6E: Next Generation [IEEE 802.11ax (2021)]

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Wi-Fi 6E includes the 6 GHz band, which adds 14 more channels. However, the higher frequency means shorter wavelengths and more difficulty passing through dense walls and floors. Wi-Fi 6E is also not backward compatible like Wi-Fi 6. 6E provides a faster transmission lane for 6E devices at both ends.

Wi-Fi 6E can utilize up to 14 additional 80 MHz channels or seven additional superwide 160 MHz channels in 6 GHz for applications such as high-definition video streaming and virtual reality. Wi-Fi 6E devices leverage these wider channels and additional capacity to deliver greater network performance and support more Wi-Fi users at once, even in very dense and congested environments. Wi-Fi 6E will bring greater technology advancements in Wi-Fi that will introduce new use cases, such as unified communications, cloud computing, and telepresence, and accelerate the next generation connectivity with 5G networks.

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4.9. Wi-Fi 7: Next Generation [IEEE 802.11ax (2023 – 2024)]

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802.11be, branded as "Wi-Fi 7," operates in the same three bands as Wi-Fi 6E. Wi-Fi 7 is expected to quadruple speed up to 40 Gbps.

The next generation of Wi-Fi with wireless routers debuting in 2023. Wi-Fi 7 is the Wi-Fi Alliance branding of the 802.11be standard from the IEEE. It uses 4096QAM, four times the modulation of Wi-Fi 6, and double the channel widths from 160 to 320 MHz. Wi-Fi 7 operates in the same 2.4, 5 and 6 GHz bands as Wi-Fi 6E, and it adds Multi-Link Operation (MLO), which enables devices to transmit over multiple bands simultaneously.

Wi-Fi 7 builds upon the foundation started with Wi-Fi 6 and Wi-Fi 6E but also includes 320 MHz bandwidth channels and 4K QAM modulation.?Wi-Fi 7 introduces some new, disruptive techniques, including something called multi-link operation (MLO). MLO allows spectrum to be concatenated from various bands. This can be used in various ways: for multi-band link aggregation to reach a higher throughput; to select the best link (using the 2.4 GHz, 5 GHz, or 6 GHz band) for lowest latency; to enable simultaneous downlink and uplink transmission; to balance traffic across bands; or to reach a higher efficiency, which is especially beneficial if one link has a large amount of traffic or interference. Our Wi-Fi 7 devices also have advances that mitigate interference, improve signal performance, and much more. It is expected that MLO will be particularly beneficial for certain use cases such as large file downloads, video streaming and virtual reality because it can “unlock higher throughputs by aggregating separate radio links to create wide channels in congested environments.”

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5. Wi-Fi Use

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Wi-Fi has become so widely used to connect mobile devices to the Internet that Wi-Fi is sometimes thought to be the "only" access method there is. However, that notion is misleading because Wi-Fi is only one of three connection methods with the other two being Cellular wireless connectivity and Ethernet Wired connectivity.

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5.1. Smartphones and Some Tablets

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Smartphones all have Wi-Fi but they can also connect to the Internet via their cellular service. Tablets all have Wi-Fi, and about 10% of them have built-in cellular capability.

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5.2. Tablets and Virtual Assistants

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Wi-Fi is built into all tablets and stand-alone virtual assistants such as Alexa. However, some tablets and virtual assistants can connect to Ethernet via adapters.

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5.3. Home Computers

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Home users can connect their computers directly to their router via an Ethernet cable. Laptop computers come with both Ethernet and Wi-Fi, and either one can be used. Laptops can also be fitted with cellular connectivity when traveling.

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6. Wi-Fi Calling

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Making phone calls over a Wi-Fi network. Both the phones and carrier infrastructure must support Wi-Fi calling, prioritizing voice over data in the real-time environment of voice. With a single mode phone, users make calls only within a Wi-Fi hotspot. Dual-mode phones seamlessly switch between the cellular carrier and open or pre-qualified Wi-Fi hotspots.

Wi-Fi calling was designed to eliminate dropped calls in areas where the cellular signal is weak. It also saves money for customers who have carrier plans with a fixed number of monthly minutes. Also called "voice over Wi-Fi," "Wi-Fi telephony," "wireless VoIP," and "voice over wireless LAN" (Vo-WLAN).

People are also able to make voice calls over Skype, FaceTime and various other apps, providing the recipients have the same program installed in their computers or mobile devices.

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7. Wi-Fi Hotspot

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The geographic boundary covered by a Wi-Fi (802.11) wireless access point. Typically set up for Internet access, anyone entering the hotspot with a Wi-Fi-based laptop, smartphone or tablet can connect to the Internet, providing the access point is configured to advertise its presence (beaconing) and authorization is not necessary. If authorization is required, the user must know the password. In addition to Internet access, all shared folders on everyone's computer currently in the hotspot are also accessible.

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7.1. Create Your Own Hotspot

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Wi-Fi hotspots can also be created by users from their smartphones, tablets or third-party device that plugs into the vehicle's maintenance port.

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7.2. The Wi-Fi Network May Be Hidden

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An access point is invisible if it is not advertising its presence. To gain access, a user must know the network name and most likely the password as well.

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7.3. Public Hotspots

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According to JiWire, Inc., at the beginning of 2010, there were more than a quarter million public hotspots around the world. However, every home or business Wi-Fi network is a hotspot, and if the wireless router is left in its default state, which advertises its presence and does not require a password, it too is inadvertently a public hotspot.

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8. Wi-Fi Direct

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A variation of the Wi-Fi ad hoc standard that allows two devices to communicate without an access point or computer in between. Wi-Fi Direct was introduced in 2009 by the Wi-Fi Alliance. Whereas regular Wi-Fi "ad hoc" mode allows computers to relay signals in a mesh network without access points (APs), Wi-Fi Direct works only between two devices like Bluetooth, but faster.

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9. Passive Wi-Fi

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A Wi-Fi technology developed by the University of Washington for low-power sensors and mobile devices. Passive Wi-Fi is said to use 10,000 times less power than regular Wi-Fi and 1,000 times less than Bluetooth LE (Low Energy) and ZigBee.

When a device transmits a Wi-Fi signal, its digital baseband processor modulates the carrier frequency using tens of microwatts of power. However, the analog RF chip that generates the carrier frequency consumes hundreds of milliwatts of power, an order of magnitude more than the baseband processor.

In a Passive Wi-Fi environment, a hub plugged into an AC outlet continuously transmits the analog carrier frequency. The Passive Wi-Fi device reflects this signal modulated with its own data packets to the receiving device up to 100 feet away at 802.11b speeds (11 Mbps). Because the device does not generate the RF, it uses dramatically less power. To use this technology, wireless routers and access points must also have Passive Wi-Fi built in.

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10. Muni Wi-Fi

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(MUNIcipal Wi-Fi) A Wi-Fi hotspot run by a city or other municipality. The service can be free or paid or a mix of both. For example, in public parks and libraries, the service may be free, but a monthly fee may be required in residential neighborhoods. Muni Wi-Fi networks emerged in the 2005 timeframe, in the US, with Philadelphia and San Francisco being the two largest cities at the forefront.

Earthlink built the Philadelphia and San Francisco infrastructures but dropped the projects in 2008. Philadelphia residents had not signed up for the low-cost service in sufficient numbers, and the system needed more routers mounted on public utility poles than initially thought. Although Google planned to sponsor the San Francisco venture through advertising, Earthlink management changed direction. Other Muni Wi-Fi projects were also abandoned due to insufficient user subscriptions. On the other hand, municipalities that used the network for governmental services and guaranteed a certain amount of financial support have been successful.

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11. Wi-Fi Comparisons

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11.1. Wi-Fi vs. Ethernet

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Wireless versus wired. Wi-Fi is the wireless counterpart to Ethernet, which is the universal standard for local area networks (LANs). In both homes and offices, networks are generally a mix of Wi-Fi and Ethernet. Most stationary machines are cabled together via Ethernet because there is an Ethernet port on every modern computer. Wi-Fi networks (Wi-Fi hotspots) are set up for laptops, smartphones, and tablets. However, any desktop machine can be made wireless with an adapter.

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11.2. Wi-Fi vs. Cellular

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The two major categories of wireless Internet access are Wi-Fi local area networks (LANs) and cellular wide area networks (WANs). In a nutshell, Wi-Fi reception is within a Wi-Fi hotspot, which varies from approximately 50 to a couple hundred feet from the transmitter (access point). Cellular is everywhere, although it may be poor or nonexistent inside a building or in rural locations.

Wi-Fi is standard equipment on mobile devices, and a Wi-Fi hotspot for Internet access is built into the wireless router commonly used at home or in a small office. When not at home, free Wi-Fi hotspots are available in public venues as well as on the street in many neighborhoods. However, airports and other venues may charge for access.

Cellular service is built into smartphones, which of course are cellphones, but cellular is also an option for tablets and laptops. To add cellular service to a Wi-Fi-only tablet. To add cellular to a laptop.

Cell service in a crowded city is typically slower than a public Wi-Fi hotspot, and it crawls compared to Wi-Fi at home with fast cable or FiOS access. However, 4G LTE cellular may be faster than public Wi-Fi or even home Wi-Fi with a slow DSL connection. Although many initial 5G rollouts have been only on par with 4G, 5G is ramping up to be faster than both 4G and public Wi-Fi hotspots.

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11.3. Wi-Fi vs. Bluetooth

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While both are wireless technologies and Wi-Fi and Class 2 Bluetooth have a similar range of about 300 feet, most Bluetooth devices are Class 3, which spans about 30 feet. Wi-Fi also supports many mobile devices per hotspot (Wi-Fi region), whereas Bluetooth is primarily a one-to-one connection. Wi-Fi is widely used to transfer data at high speed whereas Bluetooth is much slower, although more than ample for earphones, keyboards and mice.

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11.4. Wi-Fi vs. Internet

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Wi-Fi and Internet are closely related and often used interchangeably, but there are important distinctions between the two. First and foremost, the Internet is a?wide area network (WAN)?that uses a series of protocols to transmit information between networks and devices around the world. Wi-Fi, on the other hand, is simply a means for connecting devices without cables.

It’s entirely possible to have a Wi-Fi connection with no Internet access if there is no modem or Internet service from an ISP. For this reason, the signal strength of a Wi-Fi network is not directly correlated to the Internet speed a user might experience when connected. It is also why isolated Internet connectivity issues are usually attributed to the user’s device or Wi-Fi network router as opposed to the ISP’s service.

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12. Wi-Vi

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(WIreless-VIsion) Using Wi-Fi to locate moving objects behind walls. Two signals are transmitted; one the inverse of the other. When reflected back from the wall or non-moving objects behind the wall, the signals cancel themselves. However, moving objects behind the wall cause the reflections to change, which can be detected. The advantage of this technology is that it can be built into small handheld devices.

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13. Open Wi-Fi

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Open WiFi is a?Telecom Infra Project (TIP)?initiative attempting to disrupt the Wi-Fi industry through disaggregation and open-source software development. It promises to lower the total cost of ownership (TCO), end age-old vendor lock-in, and substantially expand the ecosystem.

Today's Wi-Fi network systems are monolithic. All the hardware, software, and cloud components are proprietary and come from the same vendor. That has led to the inevitable vendor lock-in, which has resulted in a higher cost structure, less flexibility and a very high entry barrier.

TIP's OpenWiFi is set to change all that through a disaggregated software system approach. As shown in the figure, it includes enterprise-grade access?point (AP) firmware, cloud controller SDK, and white-box AP, all designed and validated to work seamlessly together. The software is fully community-developed and offered as a free, open-source stack.

The biggest allure of OpenWiFi is its lower TCO, mainly because the basic software is open-sourced (free), and open systems create a highly competitive and cost-effective marketplace. The absence of huge R&D spend considerably lowers the entry barrier. Solution providers and customers can mix and match "best of breed" parts to offer the best possible Wi-Fi performance, achieve flexibility, scalability and quick time-to-market.

OpenWiFi has found strong initial traction in emerging markets. These are places where robust connectivity is seriously lacking, require highly cost-effective solutions, and are usually greenfield deployments without any legacy systems or business arrangements to support. With low TCO, a large ecosystem hungry for business, and a mission to connect the unconnected, this technology is a perfect match for such markets.

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14. References

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