In the early days of the virtual line, data transfer rates were quite low. Radio channel was used to perform tasks, functioning at speeds up to 1 Mbit/s, in rare cases – up to 2 Mbit/s. The primary high-frequency format was called IEEE 802.11a, and it allowed for speeds up to 54 Mbps, which at the time was very fast. The devices were functioning at 5 GHz.
WiFi
WiFi operates in the unlicensed ISM spectrum; it is trivial to deploy by anyone, anywhere; and the required hardware is simple and cheap. Not surprisingly, it has become one of the most widely deployed and popular wireless standards.
The name itself is a trademark of the WiFi Alliance, which is a trade association established to promote wireless LAN technologies, as well as to provide interoperability standards and testing. Technically, a device must be submitted to and certified by the WiFi Alliance to carry the WiFi name and logo, but in practice, the name is used to refer to any product based on the IEEE 802.11 standards.
The first 802.11 protocol was drafted in 1997, more or less as a direct adaptation of the Ethernet standard (IEEE 802.3) to the world of wireless communication. However, it wasn’t until 1999, when the 802.11b standard was introduced, that the market for WiFi devices took off. The relative simplicity of the technology, easy deployment, convenience, and the fact that it operated in the unlicensed 2.4 GHz ISM band allowed anyone to easily provide a "wireless extension" to their existing local area network. Today, most every new desktop, laptop, tablet, smartphone, and just about every other form-factor device is WiFi enabled.
§From Ethernet to a Wireless LAN
The 802.11 wireless standards were primarily designed as an adaptation and an extension of the existing Ethernet (802.3) standard. Hence, while Ethernet is commonly referred to as the LAN standard, the 802.11 family (Figure 6-1) is correspondingly commonly known as the wireless LAN (WLAN). However, for the history geeks, technically much of the Ethernet protocol was inspired by the ALOHAnet protocol, which was the first public demonstration of a wireless network developed in 1971 at the University of Hawaii. In other words, we have come full circle.
The reason why this distinction is important is due to the mechanics of how the ALOHAnet, and consequently Ethernet and WiFi protocols, schedule all communication. Namely, they all treat the shared medium, regardless of whether it is a wire or the radio waves, as a "random access channel," which means that there is no central process, or scheduler, that controls who or which device is allowed to transmit data at any point in time. Instead, each device decides on its own, and all devices must work together to guarantee good shared channel performance.
Of course, it takes time to propagate any signal; hence collisions can still occur. For this reason, the Ethernet standard also added collision detection (CSMA/CD): if a collision is detected, then both parties stop transmitting immediately and sleep for a random interval (with exponential backoff). This way, multiple competing senders won’t synchronize and restart their transmissions simultaneously.
WiFi follows a very similar but slightly different model: due to hardware limitations of the radio, it cannot detect collisions while sending data. Hence, WiFi relies on collision avoidance (CSMA/CA), where each sender attempts to avoid collisions by transmitting only when the channel is sensed to be idle, and then sends its full message frame in its entirety. Once the WiFi frame is sent, the sender waits for an explicit acknowledgment from the receiver before proceeding with the next transmission.
Wi-Fi protocols and specifications
The following table lists the maximum data transfer rates for each standard:
Let's talk about the most well-known and widespread types of Wi-Fi.
802.11а
This protocol started the further development of wireless data transmission. The principles were based on the basic version of Wi-Fi, the basic coding of the standard was taken. Its difference from the original version was the ability to use a frequency of 5 GHz, which allowed to increase the flow rate up to 54 Mbps. This protocol was incompatible with the 2.4 GHz frequency used before, and there was an additional inconvenience because you had to tune the reception facilities to both frequencies.
802.11b
This protocol was developed back to the 2.4 GHz frequency because it had more advantages because of the bandwidth. The developers managed to achieve data rates in the range of 5.5 – 11 Mbps. Over time, mobile devices began to operate at these levels as well. It was widely used almost until 2010, because this capacity was quite enough for computer facilities and gadgets. Today's devices can still pick up different kinds of Wi Fi, including this one, though the speed will be low.
802.11g
This is a more advanced 802.11b standard working at the same frequency but at higher speeds (up to 54Mbps).
802.11n
This was upgraded to this version by 2009. The technical capabilities of the devices had reached a level that allowed them to process heavier content, and the upgrade was very welcome. Waves are able to pass through concrete barriers. Allows multiple devices in a house to work simultaneously stably and without failures.
Can support both frequencies at the same time, MIMO has been implemented, which provides transmission speeds of up to 150 Mbps. Wi-Fi data transfer speeds are actually laid down to 600 Mbit/s, but due to interference it is much lower. In addition, to make receivers cheaper, many manufacturers eliminate MIMO altogether. Works fine on Windows platforms. The most common protocol.
What mode to choose on the router?
How to change the Wi-Fi mode in the router settings, see the following video:
All routers support Wi-Fi b/g/n protocols. A dual-band router supports the ac standard. All modern devices (tablets, laptops, smartphones, etc. e) work in these modes in the 2.4 and 5 GHz range.
Older gadgets most likely do not support the n and ac protocols. And if your router is only set to n mode, such devices simply will not connect to the Wi-Fi network. Therefore, the best option is to choose a mixed mode 802.11 b/g/n. Then both old and new devices will work. This is the mode most often found on routers from the factory.
However, if you do not have old laptops and smartphones, it is recommended to set the n standard for the 2.4 GHz band. This will increase the speed of the Internet.
Wi-Fi protocols and their characteristics, table
Each Wi-Fi protocol has its own advantages and disadvantages. The developers of the direction are constantly improving their performance, focusing on signal stability and speedup.
Classification, frequencies and ranges
There are now many varieties of IEEE 802.11, but only four types are popular: 802.11a, b, g, n. The main difference between these types of Wi-Fi is the speed indicators. For example, 11a is old and barely usable, characterized by 54 Mbps with a frequency of 5 GHz. But 11b – is already up to 11 Mbit / s and 2.4 GHz.
According to the classification of Wi-Fi, there are such varieties.
802.11a
Uses wideband modulation with direct spectral spreading. It was the first certified type (1999), and equipment that is compatible with it always has a corresponding sticker.
802.11a was hardly ever used for cell phones and smartphones. A year later, a more convenient adaptation for a variety of gadgets appeared.
The variety is characterized by the following indicators:
- Wi-Fi range – up to 50 m;
- coding – Barker 11, QPSK;
- low cost – at the level of other options;
- sending and receiving speeds of 54 Mbit/s;
- frequency of Wi-Fi channels – 5 GHz.
Range indicators are divided into three independent channels, which allows 3 virtual lines to work simultaneously in the same space. All products operating in this mode must be certified by WECA (international organization).
802.11b
This mode was formed to solve performance problems of the previous variant and began to be used after 2001. On European and Russian territories it is not widespread, it is more often encountered in Japan and USA.
What mode to choose on the router for home use
The principle of operation of Wi-Fi is based on the support of different protocols by routers: b/g/n. If the router operates in two bands, then it supports the standardization of as. Any modern device works at 2.4-5 GHz: phone, tablet, laptop, printer, MFP.
Outdated devices do not function at the latest conditions, so they are not able to connect to modern routers. For home use, mixed Wi-Fi b/g/n modes are considered optimal. When applied, there will be no problems with connectivity for new and old units. The specified scheme is preinstalled on most adapters.
If there is no such ancient equipment in the house, preference is given to "n" with a range of 2.4 GHz. This approach allows you to increase the speed capabilities of the local line.
Settings
On the pages of our portal, we've tried to lick the Wi-Fi settings options from all angles: both something specific in the spirit of the parameters mentioned in the section above, and a simple Wi-Fi setup on all devices. If you need to configure Wi-Fi, you've probably just got the wrong place for some reason. But let me reassure you: "wrong place" means just the wrong article. I recommend that you search our site for an article specific to your device model, and most likely it will be found.
Wi-Fi has become popular also because of its ease of connection. Well, really, almost any grandmother these days can connect to it and use the benefits of the Internet! But if suddenly you're not such an advanced granny, or just confuse the classic security key (password) with the WPS code, or just want to learn about different ways to connect to Wi-Fi network, I'll send you to read more about it in the article below. I don't want to paste it all here, so as not to overload it with unnecessary information
Security
Wi-Fi in current implementations is an open network (even if it's hidden) and therefore a priori designed for external connectivity. And since the technology is available from the outside, there is no super-duper security to speak of. All you need to connect to the network is a password (we know the name of the network itself).
And since it's that simple, the bad guys have jumped far in that direction: the old WPS codes and WEP encryption (and the first WPA) have many variants of successful attacks. Introduction of WPA2 made it much more difficult for attackers to guess passwords, and with a good password today it is quite a decent solution that can withstand even a handshake attack. With the arrival of Wi-Fi 6, WPA3 encryption is gaining popularity – and it's improved protection, but most importantly – for scriptkids (read as abstract in a vacuum neighborhood schoolchildren eager to get to your Internet) I have not yet seen a decent solution to implement the attack. As you understand, the issue of Wi-Fi network security is a very big topic, so again I refer you to my other article:
Read More:An article on all areas of Wi-Fi network hacking and how to protect it
