Wi-Fi is a certification label for wireless data network products, which operate according to the international standard IEEE 802.11 (wireless Ethernet, WLAN or Wi-Fi). Such products use radio frequencies in the 2.4 GHz and/or 5.0 GHz bands that may be used under unlicensed conditions. The requirements for this logo are set by the Wi-Fi Alliance.
A product is eligible for the Wi-Fi logo when it has been demonstrated by an independent certification agency that certain requirements in terms of functionality, performance and interoperability have been met. The latter is particularly important for consumers, as it guarantees that products with the Wi-Fi logo will work with products from other manufacturers.
Wi-Fi was originally pronounced ‘waifi’. Today it is pronounced as WiFi or sometimes. Wi-Fi does not stand for Wireless Fidelity.
Notwithstanding, in the past the Wi-Fi Alliance itself also used the term Wireless Fidelity in its slogan “The Standard for Wireless Fidelity”. As of the end of 2000, this slogan was no longer used in marketing material and an association with this term has been abandoned. The term was still used in documents available online, including in a February 2004 document: “… wireless fidelity (Wi-Fi) network equipment.” The Wi-Fi Alliance today discourages the use of this term, calling its use a regrettable mistake.
In everyday practice, the term, in this case written as Wi-Fi, is increasingly used as a synonym for a wireless home network in general.
Wi-Fi defines two different topologies: ad hoc and infrastructure. In ad hoc mode, an 802.11 client communicates directly with another client. The maximum distance between these stations is therefore automatically limited to the range of the two transmitters/receivers (depending on many factors, but usually a maximum of about 30 meters). Infrastructure mode works with base stations, referred to as an access point in 802.11 terms. The base stations are interconnected by an Ethernet infrastructure. Mobile stations can switch from one access point to another (‘roam’) without losing the connection to the network (compare GSM).
Many publicly accessible locations such as airports, hotels and libraries install base stations that provide the mobile computer user in these locations with Internet access and the use of information services of the respective organization. Such (semi-)public base stations are also known as dial-up points or hotspots. There are both free dial-up points and dial-up points that require a subscription or an entrance ticket for a fee. Small businesses can set up a local wi-fi network with a small investment.
The bandwidth and range of WiFi is greater than that of Bluetooth. For these reasons, Wi-Fi is one of the primary access methods for a ubiquitous wireless Internet. A downside of WiFi, especially compared to Bluetooth, is the relatively high energy consumption. This is a problem for small devices with a limited battery capacity, such as PDAs.
Wi-Fi equipment within the EU is subject to the CEPT Regulation for Short Range Devices. The conditions for license-free use impose restrictions on the transmitted power in 2015: 100 mW e.i.r.p. (“equivalent isotropically radiated power”) for the 2.4 GHz band, 200 mW e.i.r.p. for the 5.1-5.3 GHz and 1 W e.i.r.p. bands for the 5.4-5.7 GHz bands).
500 mW is allowed in some countries. There are therefore also 500 mW WiFi devices for sale, sometimes claiming a range of 1000 meters. With special directional antennas, a distance of 500 meters can be bridged with 100 mW.
An important point of attention in Wi-Fi networks is the security of the information sent over the air. A WiFi connection can be encrypted using various techniques. The two prominent standards are WEP and WPA. The WPA standard was standardized as IEEE 802.11i in June 2004, and WPA2, an improvement on WPA, has been widely used since 2006 and is required for Wi-Fi certified equipment. WEP security appears to be easy to crack in practice; WPA or WPA2 are therefore recommended. WPA can only be cracked with a lot of effort, and WPA2 hardly or not at all. However, in October 2017, it was revealed that Wi-Fi networks worldwide are vulnerable due to multiple WPA2 security vulnerabilities.
Wi-Fi Protected Setup (WPS)
WPS is designed to be able to configure the wireless connection without having to enter complicated passwords (WEP key or WPA keys). It can be done in two ways: Push Button and WPS Personal Identification Number (PIN). With the Push Button method, a special WPS button on the wireless router and on the connecting device must be pressed within approximately 1 minute. Both devices then automatically exchange the key and the connection is established. Most devices, including wireless USB dongles, support push-button setup. Some laptops, iOS devices and other devices do not support Push Button because the function is missing.
The second method, ‘PIN’, requires entering a PIN. This can be done in two ways:
1. the connecting device automatically generates a PIN to be typed into the wireless router, or
2. the wireless router generates a PIN code that must be typed into the device.
The first method is cumbersome because first a pin code is generated by the laptop, then you have to log in to the router and only then can the pin code be entered. The second method is easier because the same PIN is always used, which is often on a sticker at the bottom of the router or in the manual and can therefore be typed directly. The second method is also useful for smartphones or tablets. A smartphone or tablet user then only needs to enter the network PIN on his/her device to log in.
The PIN is not a random number but consists of 8 digits. The first 7 may be chosen randomly (0..9), the last is a “checksum digit”. It is calculated as follows: add the numbers in the odd positions, multiply the number by 3, add the numbers in the even positions, calculate the remainder when dividing by 10, and subtract that remainder from the number 10 Example: PIN=66323211. The first 7 digits are 6632321. The sum of the digits in odd positions is 6+3+3+1=13. Multiplication by 3 yields 39. The sum of the digits in the even positions is 6+2+2=10. Added up, this yields 39+10=49. Dividing by ten gives remainder 9. Subtracting remainder 9 from 10 gives 1; so the last digit of the PIN is 1.
Using a special QR code, a mobile device can easily be linked to a specific access point.
The used license-free bands of 2.4 GHz (short for Gigahertz) and 5 GHz are shared by different users. The 2.4 GHz band is the same band in which microwave ovens (for heating food, for example) also operate, but many wireless applications use the same band, such as wireless mice and keyboards, video transmission (security cameras and second television connections), wireless doorbells, garage door openers, headphones and many other equipment. When using this equipment, it is recommended to watch the different channels within the 2.4GHz band and select the channel with the least interference. The 5GHz band (2009) has fewer competing users, but because the use of this band is expected to increase, the mutual disruption will also increase. The effects that the user may notice are: loss of data connections, image disturbance, non-functioning wireless control. This concerns underlying interference in the same frequency band that may be used and is therefore not seen as a violation of the EMC standards, which describe the mutual interference with other types of equipment.
There are different WiFi standards:
- IEEE 802.11a operates in the 5.8GHz band and the bandwidth is up to 54 Mbps.
- IEEE 802.11b operates in the 2.4GHz band and the bandwidth is up to 11 Mbps. This technology has been out of business for some time (since mid-2005) and is considered obsolete. Nevertheless, many laptops are still being made that support this type of Wi-Fi standard.
- IEEE 802.11g is the successor to 802.11b and works in the 2.4GHz band, the bandwidth is up to 54 Mbps. The products that use 802.11g can also handle the 802.11b standard.
- IEEE 802.11n operates in the 2.4 and 5.8 GHz bands and multiple antennas. The bandwidth of the n version is at least 150 Mbps, and can be as high as 600 Mbps. This is 10 times faster than the predecessor to the standard (802.11g). In August 2009, the IEEE 802.11n became an official standard. Until that time, there had been equipment that worked with the provisional standard (IEEE 802.11n draft 2.0) for several years. The English word ‘draft’ stands for ‘concept’. From 2006 to 2009, all kinds of equipment were compliant with the IEEE 802.11n draft.
- IEEE 802.11u enables roaming over Wi-Fi networks. A device can use external Wi-Fi networks to automatically connect to the Internet.
- IEEE 802.11ac only works in the 5.8GHz band, via multiple antennas.
In 2011, the International Agency for Research on Cancer of the World Health Organization placed high-frequency electromagnetic fields from mobile phones and Wi-Fi, among others, in category 2B: ‘possibly carcinogenic’. In 2005, a meta-analysis of studies that included a total of 725 individuals who claimed to have electrosensitivity found that no evidence could be found to support their claims. According to the Dutch government, electromagnetic radiation does not pose any health risks.
The UK Health Protection Agency (HPA) reported in 2014 that the frequency of Wi-Fi networks is roughly equal to that of FM radio, TV and mobile phones. Since Wi-Fi networks do not transmit data continuously, the organization states that in practice there is less exposure to Wi-Fi radiation than the radiation from mobile phones. In 2007, in response to a disturbing media report from the Panorama TV program warning about Wi-Fi radiation in classrooms, the organization called for research into the health effects of Wi-Fi radiation. After the completion of this study, the HPA concluded in September 2011 that during a typical lesson the wireless network is hardly active and the exposure is therefore relatively small.
In the Netherlands, the municipality of Alphen aan den Rijn had research carried out by Wageningen University after officials pointed to radiation as a possible cause of the tree damage. The first publication of research results in November 2010 suggested that electromagnetic radiation might play a role in deteriorating tree health: in the laboratory situation, it appeared that leaves of ash trees, after more than three months of exposure to the radiation from so-called Wi-Fi Access Points, dry up and die. However, no association with deteriorating health could be established. A follow-up study, which took more account of other factors, found that a causal relationship could not be established between electromagnetic radiation (from Wi-Fi routers and UMTS and DVB-T transmitters) and tree damage such as bark nodules, bark cracks, bark necrosis and bark haemorrhage.
Nintendo (Japanese: 任天堂 “Nintendō”) is a company founded in Kyoto, Japan by Fusajiro Yamauchi on September 23, 1889.
Nintendo started out as a manufacturer of handmade hanafuda cards, for use in a Japanese card game of the same name. In the second half of the twentieth century, the company started experimenting with other products, including toys. Through toys, Nintendo ended up with computer games: in the 1970s, the company started developing and producing coin-op machines or play equipment. In 1980, Nintendo released its first portable console: the Nintendo Game & Watch.
Nintendo distributed a re-release of the Game & Watch game Ball through Club Nintendo between 2010 and 2015.
Series from Nintendo
Nintendo has many different series that it produces. The oldest are Donkey Kong and Mario. These two have also become two of Nintendo’s most popular series over time. Mario is now even the mascot of Nintendo. Other series from the arcade era are Punch-Out!! and Balloon Fight. A few years later, The Legend of Zelda also came into view at Nintendo. This series became a success at Nintendo. Such a success that they now develop an average of two parts per Nintendo console.
That same year, Kid Icarus also came into the spotlight with a game. The series was not as well known as The Legend of Zelda or Mario, but it did get a Game Boy sequel. After two decades, the game got another sequel to the Nintendo 3DS, called Kid Icarus: Uprising. Also in the year of The Legend of Zelda and Kid Icarus, the first Metroid game also came out. Metroid was intended for a slightly older audience than Nintendo’s other games. A while later, Nintendo also released other series such as Kirby (platform game), F-Zero (racing game), Fire Emblem (turn-based strategy), EarthBound (RPG), Pokémon (RPG), Star Fox (on-rail shooter) and Pilotwings (flight simulator).
Around 2003 Nintendo also introduced several simulation games, such as Animal Crossing, which simulates village life, Nintendogs, which trains dogs and cats, and Wii Fit, a fitness game in which one can train calories off. Pikmin, Splatoon and Xenoblade are three of Nintendo’s latest non-casual game series.
The part of the above article about Nintendo or an earlier version is (partially) copied from the page on the Japanese History Wiki of the Japanese Studies course at KU Leuven, which is licensed under the Creative Commons Attribution – Share Alike 3.0 license. See the editing history there for a list of authors.
All above images are licensed by their respective owners, thanks to pixabay.com