Making sense of all the different types of Wi-Fi

802.11ac, 5GHz, Wi-Fi “Plus”… I don’t have time for all thise nonsense, just tell me how to make it work fast!

Everyone’s worst fear: To be stuck in your bathroom, doing your business, when suddenly your Wi-Fi connection drops. What are you supposed to do without Internet? Read the ingredients of your shampoo bottle, like your ancestors did?

Jokes aside, setting-up a Wi-Fi connection that’s fast, strong, reaches all the rooms in the house is no easy feat, and all the different versions, standards and frequencies don’t help. I’ll try to give a crash-course on this topic.

Different versions of “Wi-Fi”

This may shock you, but Wi-Fi wasn’t always as fast as it is now. These are the different versions of Wi-Fi that were created over the years, and are still in use now (I don’t want to fill your head with esoteric bull***t that no one uses anymore):

  • 802.11b: Introduced in the year 2000. Its maximum theoretical bandwidth is 11 Mbps. That’s lowercase b, which means bits, not bytes. It translates to maximum theoretical downloads of about 1.4 MB/s.
  • 802.11g: Introduced in the year 2003. Its maximum theoretical bandwidth is 54 Mbps (6.7 MB/s).
  • 802.11n: Introduced in the year 2009. It allows the router and the device to have multiple antennas, so the total bandwidth achievable depends on how many simultaneous connections can be made. For example, if the router has 4 antennas but the laptop has 2, only 2 connections can be established. It can reach up to 150 Mbps per connection.
  • 802.11ac: The fastest version currently available. Depending on the channel width and number of antennas, it can reach up to 1.3Gbps (162 MB/s).

Just so you have a baseline, any decent router can give 1Gbps of bandwidth using an Ethernet cable, and that’s been true for years. A wired connection is also more power-efficient, has less latency, and of course is much more resistant to interference and attenuation.

Those bandwidth numbers may seem good on paper, but that’s on a laboratory, shielded from any external interference, and with the router close to the device. In real-world scenarios, you’ll probably never get half the maximum speed of your connection.

Bands and channel widths

Oh, you thought that was all? Nope!

Wi-Fi traditionally uses the 2.4GHz band. That’s the same band Bluetooth uses (this piece of information will become relevant later). That band is also divided in 20MHz channels. So, if you have configured your router to use “Channel 1”, you’ll be transmitting at 2400-2420MHz. If you choose “Channel 11” (usually, the highest, although that depends on your country’s regulations), you’ll be transmitting at 2450-2470MHz.

Wi-Fi version 802.11n allows the channels to be wider, 40MHz to be precise. That allows double the bandwidth per-channel. Wi-Fi version 802.11ac just goes crazy with that idea and allows channels of up to 160MHz.

Starting with 802.11n, Wi-Fi can transmit in the 5GHz band too. The 5GHz band can use wider channels, and because it’s a relatively new addition, it’s less saturated than the 2.4GHz band. But, because of physics, that transmission doesn’t travel well through obstacles.

Enough theory, how do I configure my router?

Enough theory indeed. Let’s assume that you already have a router. The first thing you need to know is its capabilities. If you got it in the latest 2 years or so, it probably has 802.11ac. If not, unless it’s incredibly old, it will have at least 802.11n.

If the router is modern, it probably has 5GHz capability. Those routers usually provide 2 different Wi-Fis at the same time: One in the 2.4GHz band, and another on the 5GHz band (usually named “Wi-Fi Plus” or some marketing gimmick like that). So, you can connect your laptop to the 5GHz and your old phone to the 2.4GHz. Apple hardware usually has 5GHz capabilities too, even if it’s older. My old 2011 MacBook Air and the Time Capsule I bought at around the same time both have 802.11n and support for 5GHz.

The next thing to know is the capabilities of your devices. Some rough estimates:

  • 802.11g: Super-old budget smartphone.
  • 802.11n: Kindle, 4-year-old high-end computer, 2-year-old budget computer, any Internet of Things device, 2-years-old budget smartphone.
  • 802.11ac: 3-year-old high-end smartphone, 3-year-old high-end computer.

Of course, a modern device can connect to older kinds of networks. The best way to confirm if your device supports a version of Wi-Fi is to configure your router to use only that version and then try to connect. But it’s not really that important to know.

If you use Bluetooth, use the 5GHz Wi-Fi. Laptops usually use the same antenna to transmit Wi-Fi and Bluetooth, so if they are trying to transmit at the same frequency (remember, Bluetooth uses the 2.4GHz band) there will be a lot of interference. With my Dell XPS laptop (a high-end computer), if I’m connected to a 2.4GHz network I practically can’t use my Bluetooth mouse.

If you live in a big house, use the 2.4GHz band. A 2.4GHz signal can easily travel through 2 or 3 walls before attenuating a lot. Laptops have bigger antennas, so they can get stronger signal, but smartphones are more problematic. If you connect a smartphone to a 5GHz Wi-Fi and go to the next room, chances are your speed will drop drastically.

If you have a lot of neighbours, use the 5GHz band. That’s the plus side of the 5GHz band not being able to travel through obstacles: your neighbour’s Wi-Fi can’t generate as much interference on your home. Plus, 5GHz being a relatively new addition, chances are that most of your neighbours won’t be transmitting in that band at all.

Speaking of neighbours: channel selection. If your neighbour is using Channel 1, switch to Channel 6 or higher so there’s no overlap. If they’re using Channel 6, use Channel 1 or 11. Leave 5 channels in between you. Of course, with multiple neighbours that trick is not so easy. The best thing to do is just let your router configure the channel automatically, it will pick the less congested band.

Channel width: Routers will usually let you pick whether you want 40MHz channels, 20MHz channels, or support both kinds at the same time. Just leave it to “support both”, there’s no reason not to.

Wi-Fi version: Routers will also give you the option to configure which versions to support. For example, if the router is 802.11n, it will give you these options:

  • 802.11n only.
  • 802.11g and 802.11n.
  • 802.11b, 802.11g and 802.11n.

Just leave it with support to all of them. Again, there’s no downside to that.

Tell us Daniel, how do you have your router configured?

I’m glad you asked, voice in my head. Let it serve as a small example. I live in a small apartment, the router is in the living room, and there aren’t a lot of neighbours. My router supports 802.11ac, and it provides 2 Wi-Fi signals: One at 2.4GHz and another with 5GHz. I have left the Channel and channel width to “Automatic”, and Wi-Fi support to 802.11b/g/n/ac (I don’t want having a guest with an old phone and it mysteriously not working).

These are my devices:

  • OnePlus 3 (smartphone): Supports 5GHz and 802.11ac. I have it connected to the 2.4GHz network, because if I use the 5GHz the signal drops when going to the next room. I don’t really need ultra-fast speed on my phone anyway.
  • Kindle (e-reader): Supports 802.11n (I think). I have it connected to the 2.4GHz network. I almost don’t use the Wi-Fi on this one, I don’t really care if a book takes 2 more seconds to download.
  • Dell XPS 15 (laptop): Supports 5GHz and 802.11ac. I have it connected to the 5GHz network. As I said, if I connect it to the 2.4GHz, the Bluetooth mouse becomes jittery. I work in the same room where the router is, so range isn’t an issue.

This kind of arrangement won’t work for everyone, but I think it’s a good baseline. Basically, pick 5GHz unless you need extreme range, and keep the default router options (all versions of Wi-Fi supported, automatic channel selection, etc). Also, if you have a lot of neighbours and your router doesn’t support 5GHz, do yourself a favour and invest in one that does. The difference is abysmal.

I hope I’ve shed some light into the matter, and not confuse you even more, my hypothetical reader. Please tell me in the comments if you have any doubt or question with your setup.

Space travel technology in Science Fiction

The many ways we could be going from one place to another, according to some of the best creative minds in our time.

I’ve been consuming a lot of science fiction lately. I can’t really explain, being as nerdy as I am, how could I go through most of my young life without immersing myself into Doctor Who, Star Trek or Galactica, but I’m trying very hard to correct that.

One constant in almost all modern sci-fi, is the existence of some kind of technology to allow interstellar travel. A science fiction movie would be pretty boring if it just consisted on people waiting for decades to go into our nearest star system. I’ll try to summarize the different kinds of technology present in those stories.

Sub-light engines

Moon
You don’t need a fancy starship to go there.

In the first category you have spaceships that can travel at sub-relativistic speeds, that is, much lower than the speed of light. That includes, for example, early works of science fiction like Jules Verne’s From The Earth To The Moon. Those kind of engines are only good enough to travel inside our Solar System, and depending on the destination it could take years. Since we know that there’s no other habitable planet inside those confines, the variety of different stories that can be crafted using these engines is quite limited.

In the early 20th century, a trip to the Moon was considered sci-fi, but something happened in 1969 that made all those kind of stories obsolete, and prompted fiction writers to expand their universe (pun intended). That made it necessary to imagine new kind of engines and associated technologies to keep being one step ahead of reality.

Hermes
They’re coming to get you, Whatney! … Eventually

Sub-light travel is perfectly fine, of course, when the action doesn’t go outside of our Solar System. The amazing book The Martian, and its good movie adaptation (I don’t want to be one of those guys but… go read the book. Seriously. It’s amazing.), just have to go to Mars. Since it’s striving for realism, the plot doesn’t need interstellar travel, starship battles, encounters with little green men or anything of that sorts. In fact, it looks like something that could totally happen in 10 years if NASA had a bigger budget.

In 2001: A Space Odyssey, they only need to go as far as Jupiter. In Elysium, the plot revolves around a giant space station orbiting Earth.

The possibility of all those trips can be explained using just improved versions of already existing technology, it doesn’t require a new, revolutionary mumbo-jumbo engine that can challenge the reader’s suspension of disbelief.

With cryogenic sleep

Passengers
Yep, we should be asleep, but then the movie would have been pretty boring.

Sub-light travel is easy enough (we are doing it every time we walk), but how can you devise a story in space, in another star system, with contacts with another alien race, etc with just conventional engines? An easy plot device that doesnt complicate things much and it’s still within the realms of plausibility: cryogenic chambers. So, in some cases the starships are slow, they take decades (even centuries) to reach their destination, but their passengers are in a state of suspended animation. Frozen, if you like. So, when they reach their destination, somehow they are woken up without having aged a single day.

Many sci-fi works rely on this plot device (such as Futurama or the Alien franchise), but I haven’t found any story that uses just that technology for travel, except for Passengers.

Side note: It’s uncanny how that “45 light-years” distance is similar to the distance of the exoplanets found by NASA a few months after that movie was released.

Passengers is an okay movie (Chris Pratt and Jennifer Lawrence are fine actors, the special effects are decent, and the premise is interesting) about a starship that travels to an Earth colony 45 light-years away from Earth. It flies at half the speed of light, so it takes 90 years to get there. All its passengers and crew are supposed to stay in a state of suspended animation during the whole trip (spoiler alert: some of them don’t).

With generational ships

Serenity
Backstory of Firefly/Serenity. Big ships leaving Earth because we are really bad at caring for the environment.

Another “simple” way to colonize other star systems without inventing a way to defy Physics is the use of generational ships. That sounds fancy, but it just means that is a starship prepared to be in flight during several decades (even centuries), so there will be several generations of people which will have born, lived and died in-flight. That’s the basic premise of Firefly, for example. In that universe, faster than light travel doesn’t exist. At some point in the future, Earth becomes uninhabitable, mankind discovers an inhabitable solar system, they build ships to go there and they simply go. That’s all in the backstory to the show. Since all the habitable planets are in the same star system, “conventional” engines are good enough from that point on.

We know that the closest star to Earth is Proxima Centaury, which is 4.2 light-years away. We also know that it has no habitable planets. So, nothing will convince me that a ship at sub-relativistic speed can reach a habitable solar system in less than 40 years. If there’s no cryogenesis or life-prolonging technology available, then the only possibility is to load the ship with enough provisions, make it big enough so you can accommodate enough people and in-breeding doesn’t become an issue, and just prepare to spend the rest of your lives, and your children and grandchildren lives, in a long trip.

With the help of space anomalies

Wormhole
Representation of a wormhole in a fold of spacetime.

Even if your puny species only has primitive sub-light vehicles, if you happen to find a wormhole nearby, you can get yourself into some intergalactic adventures! A wormhole, if you haven’t watched any science fiction in the latest 50 years, is like a portal between 2 regions of space. It’s called a “wormhole” because it has the shape a worm leaves in an apple, like a funnel that opens on both sides.

A wormhole is pretty much a theoretical concept, and it has to do with the theory that the space-time continuum can “fold” upon itself so a “corridor” of those characteristics can provide a kind of shortcut between 2 very distant points in space. Also, it’s a very convenient plot device.

A recent example of that kind of anomaly is Interstellar (good movie, but a bit slow, and it gets really weird until the end, and now I’m gonna stop because I feel like I’m describing 2001). Earth is about to get destroyed because, again, humans are bad at caring for the environment, but a wormhole appears near Jupiter, and at the other side (wherever that is) there are habitable planets! Eureka!

Stargate
Is this a wormhole? A portal? Who cares, it works!

I’ve only seen the Stargate movie, none of the series, so sorry if I’m wrong, but I would put the Star Gates themselves as examples of this plot device. They are sort-of like artificially-made wormholes, a network of portals connecting different regions of space, like Earth and a weird version of ancient Egypt.

Sub-light speed, but pretty damn fast

When a moving object approaches the speed of light, interesting things start to happen. Einstein’s formula (e = mc2) tells us that the speed of light can’t be reached (you can’t propel an object if it has infinite mass), but a starship could get, say, to 0.9 times the speed of light without needing to break any law of Physics (but consuming insane amounts of energy). At those speeds, time dilation starts to play a role, and every author deals with it in a different way.

In Ender’s Game, for example, ships travel at a speed close to light, so 1 year for a passenger is equivalent to 10 years on Earth. I’m not sure that’s how the Twins Paradox works, but hey, whatever works for the story.

Faster Than Light travel

In this category you have the most far-fetched kind of sci-fi. Faster than light travel is, by the current laws of Physics, plainly impossible. But if you are a writer and you are envisioning a universe with different alien species, vast star systems to explore, wars on a scale too big to comprehend, you don’t let the limits of reality stop you.

Most of the time, faster than light travel is possible by some scientific breakthrough, normally decades (or even centuries) before the setting of the main story. That’s to make it believable that the technology is commonplace. The feeling I have in most sci-fi is that a starship is as hard to obtain as an actual ship in the real world. So you can have your space cruisers, space pirates, space smugglers, space police, space military… Also, making your technology “a given” allows the author to skip the details of how it works, and focus on the main story.

Usually, due to the “mystic” nature of faster than light travel, ships have 2 types of engines. They have more “conventional” engines to maneuver at sub-light speeds, and then they have a separate, completely different “contraption” to go faster than light. Examples of this kind of technology are a lot, so I may be missing like 90% of them.

Enterprise
Star Trek ship going faster than light (warp speed), as reimagined by JJ Abrams.

In Star Trek, ships are propelled by a “warp engine”. It generates a “warp bubble” around the ship that somehow does something to the surrounding space and can make the ship go faster. Yes, it’s vague, but the technical explanation would be like 3 paragraphs of made-up words. The Star Trek ships can cover a few light-years per day, depending on what the plot demands. Still, crossing our galaxy from one extreme to another can take the finest Starship of the Federation about 70 years (that’s the whole premise of Star Trek: Voyager). There have been 13 movies and more than 300 Star Trek episodes, so in that universe we can see too a fair bit of cryosleep chambers, generational ships, wormholes (natural and artificial), time travel, God-like beings that can transport a ship in a whim, alternate universes…

Star Wars“hyperdrive” operates on a similar principle than Star Trek’s warp drive: It creates a something something that makes the ship go fast. Only in this case it’s even faster. This article goes at the calculations in depth, but basically what you need to know is that, in A New Hope, the Millenium Falcon casually covers a distance of almost half the galaxy (from Tatooine to Alderaan) in what appears to be a few days (about 10 minutes of movie time). Since the Star Wars galaxy is similar in size to ours, it’s clear that the hyperdrive is much much faster than even Star Trek’s finest warp drive. It makes sense, really, if the whole galaxy is expected to be at war at some point, having the possibility to transport from one front to another, back to the capital to debrief, back to the front lines, etc makes for a more compelling, character-driven story.

In Battlestar Galactica (the reimagined series), the ships have a jump drive. It means that, after charging some (supposedly large) amount of energy and doing some complex calculations, a ship can instantly jump from one point in space to another. It has limited range, but that particular device allows for a lot of tension in the action sequences. I don’t want to stop talking about Battlestar Galactica without recommending it, it’s amazing, specially the first season.

Nostromo
If you said this ship can’t be fast, you’d be wrong!

In the Alien franchise, ships are capable of faster than light travel. Still, some trips can take several years, so ships designed for long travels are also equipped with cryogenic chambers.

In Frank Herbert’s Dune, the fastest ships can “fold space”, which I guess it means it’s like a “jump drive”. In Doctor Who, the TARDIS can travel instantaneously both through time and space, due to some wibbly-wobbly, timey-whimey stuff (another amazing show, it’s so silly and yet sometimes it slaps you in the face with the best plots you’ve ever seen in sci-fi). In Spaceballs, the best ships can reach “Ludicrous Speed”, which is of course a lot faster than light speed. In Futurama, the Planet Express can travel faster than light making the universe move instead of the ship…

At this point, you get the gist. Every sci-fi work that relies on faster than light travel will have its own, impossible, vaguely-described contraption to make it work. And that’s ok, because the technology is usually part of the setting, part of the background. Normally, the writer wants the readers to forget about how the technology works so they can be immersed into the characters and the story.

Conclusion

If your goal, as a writer, is to strive for realism, stay away from wormholes or faster than light travel. So, either you set your story in our Solar system (The Martian, From The Earth To The Moon), you rely on generational ships (Firefly), or cryogenics (Passengers). Cryogenic technology doesn’t exist yet, but it’s not hard to imagine that it could plausibly exist about 100 years from now or so.

Sometimes the best work comes when adapting to self-imposed limitations, but other times, if the story calls for it, it’s totally advisable to ditch the realism in favor of a compelling setting. Science Fiction doesn’t need to be scientific, it just needs to be fiction.

Atlantis, an unknown board game

Today I’m gonna talk about a board game. It’s so “indie” that it hasn’t even been commercialized. I’ve been taught how to play it a few years ago by a friend of its creator and I purchased a copy from him. He told me that his friend didn’t want to copyright it or commercialize it. I want to be absolutely clear: I haven’t invented this game, but I also don’t know the name of the inventor. If you are the inventor and want me to take down this post, please contact me.

Basic info

  • Name: Atlantis (I guess, but I don’t know why)
  • People: 2 to 6.
  • Difficulty: easy to medium (I would put it in the same ballpark as checkers).
  • Time: About 15 minutes for a 2-player match, up to 1 hour for a 6-player match.

Continue reading “Atlantis, an unknown board game”

Starting a blog

How does this “Internet” thing work again?

This is the first post of my new blog, “Daniel’s Ramblings”. It’s called like that because my name is Daniel, and I’m gonna ramble a lot. I don’t love that name, but it’s better than not having it at all.

This was long overdue. I’ve been delaying this until I could think of something to write about, but I’ve realized inspiration doesn’t usually come if you do nothing about it. I’ll write about whatever I feel like it, and now I have something to make me accountable: an actual, published blog. It was much easier to procastinate when no one could see that I was supposed to have a blog.

I’ve chosen the wonderful WordPress.com service to host this site, it made it quite easy to get it up and running fast, and I don’t have to worry about DDoS attacks, security vulnerabilities, updating the software, etc.

I am a software engineer, currently working at Automattic. Originally I’m from Asturias (Spain), but now I’m living in Tenerife (Canary Islands, Spain). I can do that because Automattic is a distributed company, and so it allows employees to work from their homes.

If you can work from anywhere in the world, may as well go to a tropical island.

Me, last year

Lately I’ve been specializing in web development, I work mainly with Node.JS, React, Redux, Webpack, etc. Altough in the past I’ve done quite a bit of Android and PHP development.

I’ll try to make time and work on several side projects I have half-finished. That should make for some interesting content to blog about, I hope.

Outside of work, I enjoy swimming in the open sea, although I’ve had some disagreements with a few Portuguese Man-o-wars lately (medusas, really stingy ones). I also like board games and videogames in general (altough lately I haven’t been gaming much). Like almost everyone from my generation, I’m addicted to TV series. I also like reading Fantasy and Science-Fiction, I’m currently reading Frank Herbert’s Dune and I’m enjoying it a lot.

That’s enough for a quick introduction! If you decide to follow this blog, I’m sure you’ll learn much more about me. I don’t pretend that this blog will have tons of useful information or entertaining stories. It probably won’t. But at the very least, it will allow me to practice writing in English (not my native language), venting a bit, and expressing myself to the world in general. Sometimes, the 140 characters of a tweet aren’t enough.