The meaning of WiFi or wireless is Wire (cable) Less (without), that is to say "without cables". Wireless is understood as transmissions or equipment capable of transmitting and / or receiving data without the need to be physically connected to each other.
An example of Wireless transmission is when we put on the headphones without cables and receive the sound of the television or when we change the channel with the remote control.
From the previous examples it can be deduced that there are or exist different types of Wireless since it cannot be the same to receive sound from a television than to connect to the Internet through a laptop, on the other hand the previous example will also help us to differentiate Wireless from WiFi , the WLAN definition headphones that give us the sound are not a WiFi device since they do not comply with the 802.11b / g / n standard.
We will differentiate the wireless transmissions from the WiFi although in a more global vision they can "be the same". From this differentiation we find the Wireless via infrared or IR that is commonly used in television controls and mobile phones. The Wireless that follows the IEEE standards and the 802.11a, b, g, n and the newest Wireless standards that is regulated by the IEEE but does not follow any 802.11x standards is the bluetooth that emits at the same frequency as the WiFi devicesbut its emission capacity and scope are smaller. Bluetooth is used for communications between mobiles and different devices with a relatively lower bandwidth need.
Maximum distance reached
The scope depends on many factors. Manufacturers talk about a range of 100 to 300 meters indoors. In open environments without obstacles and with direct line of sight, the range is considered in kilometers. The factors to consider are the types of antennas, the line of sight, the emission power and the curvature of the earth .
802.11 protocol
The 802.11 protocol or standard is responsible for setting the rules and conditions or defining the parameters so that a WiFi element can access the medium, transmit or receive information .
The 802.11 protocol uses air as a means of transmission at a free emission frequency . This frequency is 2.4GHz, some variants of the 802.11 protocol also use the frequency range of 5.4GHz . These two free frequencies are incapable of crossing walls and obstacles in general, so it is very difficult to obtain good coverage if you do not have a direct view of an emitting node within the network.
The fact that this free frequency is used does not mean that we are not subject to any regulations. Currently the regulations regulate the emission power that cannot exceed 100mW .
This protocol is also responsible for defining the way in which we will access this medium. Before being able to send any message, a series of actions that the sender must execute are marked so that when it transmits, no other node can do it. Technically these actions are known as CSMA / CA (Carrier Sense Multiple Access / Colision Avoidance).
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