TechForKids WHAT’S A MOBILE?
A fable-like dive into Mobile and its internals..
Mobile has become an integral part of everyone’s life. With the immersive gaming experience and technology usage at school, kids these days are very comfortable with gadgets. Well it seems a little unreal to us embedded engineers that they take the long history for granted. Here begins the plot.
Long Long ago, around 2 decades back.. Only the rich and the powerful had the honours of owning.. A small phone with a Black and White display and a tiny keyboard, a tiny antenna and a long battery life.. It was a moment of liberation for mankind.. ability to make a call outside one’s home.. It was the era of Nokias and Motorolas..
Are you kidding? There was no Apple and Google? That sounds so wierd..
It might sound wierd. Today’s phones are topped with a whole lot of things.. Like a fondant decoration on top of a vanilla cake. And these cell phones are now called the Smart Phones.
What is this ‘cellular’ thingie?
In the dark ages of landline phones, every phone was connected to the telephone exchange by copper wires. If you had to call up your friend from Cupertino to Fremont, a circuit had to be literally set up between your house, Cupertino telephone exchange, Fremont exchange till your friend’s house. Just like setting up railway tracks for carrying the voice packets.
Phones were tethered to home and it was not possible to walk around in the streets and make a call.
And in the distant kingdom of frogs, each frog selects a distinct squeaking croak.. So they were actually communicating long distances in this wireless manner.
In the cellular age, the link between the phone and the operator was no longer copper wire. Each user spoke to the cell tower using special codes and different users were given different codes to avoid any mixups. Think of it like your teacher assigns you a code and a slot for you to answer in the class. The cell tower allocates resources to the users making requests in its cell.
What are radio waves? Are they like sea waves?
When I speak in a large room, you hear it all the way.. The sound travels like tiny waves.. But after some distance, it is not strong any more.. Likewise we have radio waves.. They oscillate very fast.. Like a million times in a second. They travel far distances in a jiffy and the phones use this to talk to the tower.
There must be so many code words.. As many people?
In a far away territory B where the croaks from territory A would possibly not be heard, the frogs over there just reused the codes of territory A. So the croak codes kept repeating in far off lands.
Just like the frogs had to reuse the code in distant lands, the towers too reused the codes in distant lands. The smart engineers divided the land roughly into hexagon cells. Each hexagon had a tower. And the gadgets that talked to these cell towers were called as Cellular Phones.
Now I get it how the cell phones work. Sometimes the signal from the tower is weak inside my home.
How does it work when we drive to a different location?
That’s a good question. Let’s say You want to drive from Cupertino to Fremont crossing Mountain View. Let’s assume each of these areas is a separate cell serviced by its tower. The phone is always listening to various towers and checks which is stronger. When you are approaching MountainView, it switches to the new tower. Making sense?
That makes Sense.. How do I receive a Phone Call? I could be anywhere and not at my home tower at Cupertino?
Now you are speaking like a little geek. There is a big network of towers and they keep talking to each other all the time. Your phone wakes up once in a while and reports the tower it is in. And when you get a call from India, the network knows you are now in Seattle and sends the message only to Seattle tower and not to Cupertino. Big strategy right?
That’s a smart network. Now tell me why are they called Smartphones?
Well, cellphones had a long history. From just being a gadget that enabled making calls, today’s phone has Camera, Storage, Internet, Gmail, Youtube and so many apps making it a Smartphone.
What ‘s inside a smartphone?
Think of the smartphone as a powerful and rich kingdom. There are different villages specialised in different skills and each one special and indispensible; the GRAPHICS village, the DISPLAY village, the CAMERA village, the VIDEO & IMAGING village, the CELLULAR village, the WIFI village and so on. In this magical land, there are roads connecting these villages at high speed.
Just like the Ninja manages so many weapons, at every village the chief with his computer manages his warriors.
And at the grand capital of the country, there lies a powerful processor. The ruler speaks the operating language of Android or iOS. He has an army of sensors reporting to him. He has all the village chiefs reporting to him.
That’s a really a big beast.. No wonder we charge it so frequently.. They are always hungry. Does the phone ever sleep?
That’s a big issue even worrying the mobile engineers.. With so many hungry troops inside a phone, it would be starving if they were awake all the time.. So the master at the centre governs which troop needs to be awake for which activity.. When you start your Camera App, the camera regiment is fed well and they perform their very best while the bluetooth and the graphics regiment may be still be in slumber..
On normal occasions when your phone is idling, the entire kingdom including the centre is in deep sleep .. Except for the trusted few GUARDIANS who wake up to any signals and alert their troop.. ALERT… like an incoming phone call, a message, change of tower..
There are GOVERNORS in the centre that decide how the centre should be.. Think of it as a 16 handed genie..Master shall I use 2 hands 4 hands or 16 hands? And at what speed do you want me to work? Dont mind if I go more hungry though says the genie. After all, kids don't want fortnight to have glitches in between.
That’s So cool.. Do they have Ninjas inside?
Not really.. But a trusted order where every team has a goal and they obey the orders of their master for achieving the ultimate goal..
Technology is awesome.. Ain’t it?
Yes, technology has enabled a lot of impossible things.. You can make a video call to grandparents who are on the other side of the globe, use KhanAcademy for your lessons and make fancy paper planes following online instructions..
However, technology can be dangerous when used without being mindful.. As kids you all get so addicted to the immersive gaming.. Our body was not designed for this.. Limit your screen time and use in moderation.
The phones are already so smart? What does the future phone look like?
I leave that to your dreams and imagination.. When you kids grow up, how you decide the future is in your hands. Ain’t it?