Mom, This! Wi-Fi

Mom, This! Wi-Fi


Remember from the last post how we send billions of "1"s and "0"s of information via wires and light? Well do you know how do we send things wirelessly? 

Wi-Fi (pronounced "Why-Fy")! Yay. 

Fun fact: Wi-Fi is a branding name for IEEE 802.11 or Wireless Local Area Network (LAN). It's supposedly sounded like "hi-fi" Interbrand-- the company responsible for naming Prozac, Celebrex, the Mitsubishi Eclipse, and the Nissan Xterra named it. Some names it could've been were Skybridge, Torchlight, Flyover, Trapeze, Dragonfly, Hornet, Transpeed and Elevate. 

Wouldn't it be strange to call something Dragonfly-enabled? Or "Mom, turn the dragonfly on!"

But anyway how does it work?

Wi-Fi works like a radio

It works the same way a radio works, kinda. Except instead of receiving sound through the air it receives information. Wireless "1" and "0" sending machines use a radio signal to send a "1" and "0" from one place to another.

The machines have to actually translate the "1" or "0" into radio waves of different frequencies. The receiving machines reverse the process and convert it back into binary on your computer. So wireless has made our Internet mobile, but a radio signal doesn't travel all that far before it completely gets garbled. This is a limitation of Wi-Fi.

This is why you can't really pick up a Los Angeles radio station in New York or vise versa. As great as wireless is, today it still relies on the wired Internet. 

The machine that sends this information is called a wireless transmitter. It creates a zone by sending out radio waves in a small area. Then your computer or phone will receive the radio waves if it has the right wireless adapter. The range of the transmitter ranges, but usually just covers a house it looks like this:

Things like walls and couches degrade the signal. You can think of it like a sound wave going through the air. The best place for a router is the center of the house. 

So when you click on a link on facebook or upload a photo, your computer or phone sends a radio signal of its own to the router. Then the router converts it back into a bunch of "1"s and "0"s and sends it through the wired network. 

So there are also different types of Wi-Fi. It comes down to speed really, but you can look at the technical specifications of the device to really know what it up. Those really small words with all the numbers that you need your glasses to read. :D

  • 802.11 - "The OG" (Original gansta, mom). 2Mbps using an unregulated radio signaling frequency of 2.4GHz. 

Unfortunately, 802.11 only supported a maximum network bandwidth of 2 Mbps – too slow for most applications. Nothing is manufactured in this, so if you find one, throw it away. 

  • 802.11b - "For the Common folk." ~11Mbps using an unregulated radio frequency of 2.4GHz also. 

They added the letter "b"! 5x faster than 802.11. But being unregulated means things like the microwave, cordless phone, or other household appliances can interfere with the signal. This is bad, but an improvement from the original 802.11!

  • 802.11a - "For the Office." ~54Mbps using a regulated radio frequency of 5GHz. 

"a"! 22x faster than 802.11. This was developed simultaneously as 802.11b, using a regulated signal so it doesn't get messed up by the microwave. But being at 5GHz means the waves are shorter, which means it has a shorter range than 802.11b, and doesn't go through walls as well. 

  • 802.11g - "Flash-y." ~54Mbps using a unregulated radio frequency of 2.4GHz. 

"g"! As faster as "a" but different frequency to make it go farther. Also works with 802.11b devices. Still uses that unregulated frequency. 

  • 802.11n - "MIMO aka more antennas." 150Mbps with one antenna, 300Mbps with two and 450Mbps with three antennas using multiple signals and antennas

"n". Super fast, 3x faster than "a" or "g." MIMO stands for multiple input and multiple outputs. So this is better because all the one previous use one antenna, but sometimes when you send a signal out and it hits a wall the signal will be scattered. This causes problems for the signal like fading, cut-out (cliff effect), and intermittent reception (picket fencing). Using multiple antennas essentially fixes this problem of scattering. 

Distance from router. 802.11n at one metre: 30MBps, 10 metres: 20MBps and at 20 metres behind two solid walls: 5-10MBps

  • 802.11ac - "Flash" 450Mbps with one antenna, 900Mbps with two antennas and 1.3Gbps with three antenna using multiple radio frequencies. 

"ac" 3x faster than "n." Uses this technology called "beamforming." Instead of casting a uniform signal across the room, it sends a "smart signal" to strengthen the signal in the direction of your device. Essentially better signal farther across the room. 

802.11ac at one metre: 90MBps, 10 metres: 70MBps and at 20 metres behind two solid walls: 50MBps

So just one thing to remember though, mom, I realize this is a lot. Your computer and phone and tablet are limited by the number of antennas they have. Typically. 

  • Smartphones: 1 antenna
  • USB Adaptors: 1 or 2 antennas
  • Tablets: 2 antennas
  • Laptops: 2 antennas (occasionally 3 on desktop replacements)
  • Desktops: 3 or 4 antennas 

This is another bottleneck. So say you read this and go and buy a "ac" router, because well its the fastest and you want 1.3GBps. Well If your glorious four antenna 802.11ac router is connecting to your single antenna 802.11ac smartphone then 400Mbps (50MBps) is your theoretical maximum and 200Mbps (25MBps) is prolly a more realistic one. 

So in summary. If you're in a coffee shop using Wi-Fi, then the bits get sent through this wireless router and then transferred to the physical wire to travel the really long distances of the Internet.

The physical method for sending bits may change in the future, whether it's laser sent between satellites or radio waves from balloons or drones, but the underlying "1" or "0" (binary) representation of information and the protocols for sending that information and receiving that information have pretty much stayed the same.

Everything on the Internet, whether its words, emails, images of your beloved son, cat videos, or puppy videos, all come down to these "1"s and "0"s being delivered by electronic pulses, light beams, radio waves, and lots and lots of love.


your son


 Softmax Regression (Maths + Neural Networks)

Softmax Regression (Maths + Neural Networks)

Mom, This! the internet.

Mom, This! the internet.