What do you think when someone mentions the word “brain”? The word “internet”? The word “job hunting”? Connections.
Throughout human progress, connections have been some of the most pronounced indicators of civilization. In fact, one could not speak of a society if there were no connections to define it – you can’t have a society with only disconnected members.
Society evolved when humans decided to group together in cities, and it again evolved when they decided to make connections between these cities. Greek and Roman societies are perhaps better characterized by their unprecedented ability to connect cities at unimaginable distances apart, both by land and by sea. Some of the roads and bridges built by the Romans to hold their empire together still stand today. But I won’t be talking about the Romans, as interesting as they might be.
There is much to discuss about connections. There’s a whole industry devoted to telecommunications, and millions are spent each year studying ways to improve how we communicate. So let’s just focus on one small aspect of connections, that of communications, and let’s concentrate on the evolution of cell phone technology. How did cell phones come about? How do they work? What’s in store for them?
The idea of a mobile phone certainly wasn’t new. If you’re a fan of war movies, you must have seen the use of radiophones to communicate the movements of the enemy. Walkie-talkies were already widespread at the time when the first mobile phone was developed. There had also been mobile phones for use in cars. You know, those fancy ones you see in limousines.
As is often the case with more modern inventions, the mobile phone was not developed in isolation. The one to patent the portable mobile phone, however, was Dr. Martin Cooper for Motorola in 1975. Kind of sad for Bell Labs, since most of the concepts were initially developed there. The first commercial cell phone network put in operation was in Tokyo, Japan, in 1979. The first in the US took about 4 more years.
Brief intermission. We all certainly have this unquenchable thirst to communicate, so why did it take so long? What was the difficulty? Many people fail to realize how hard it is to get spectrum. In actual fact, you can’t just go around broadcasting to whatever frequencies you want.
The use of frequencies is government regulated, and believe it or not, it is a very scarce resource that costs quite a bit of money. Even in recent years, you can hear about spectrum allocation – in 2008, there was a lot of noise about it in India, and just recently, AT&T bought some for 1.9 Billion Dollars. End of intermission.
The communication system used for cell phone communication in the early eighties was AMPS (Advanced Mobile Phone System). It was analog. The problem with analog is that whenever you make a call, it would take up a band of frequency for that communication channel. So, if you have limited frequencies, there is a limited number of channels you can use. Frequencies are expensive, so if you run out of channels, you’re stuck. You can’t get more subscribers, so you can’t make more money.
In the nineties, several new, digital, standards were established. As with most standards, the world couldn’t make up its mind on which standard to use. The three major ones are TDMA (time division multiple access), CDMA (code division multiple access) and GSM (Global System for Mobile Communications).
CDMA uses some convoluted encoding scheme that was originally developed during World War II by the military to prevent the enemy from intercepting transmissions. It splits up your data to a bunch of random spectrum bands, and it does the same for everybody else’s data, and since it’s random, they don’t overlap. These digital technologies are commonly referred to as 2G. Their use of spectrum is much more efficient than analog, and they allow for everyone’s favourite, SMS, or text messaging.
The next generation, 3G, uses a number of standards, but the most common one is W-CDMA, or wideband CDMA. Nothing much to say here – just another standard, with a few variations. The difference between 2G and 3G is mostly in the transmission speeds, and some other characteristics that must be satisfied. Chances are your phone right now uses 3G.
Speaking of phones, there has been one major shift in recent years – the advent of the smart phone. The standards mentioned so far were mostly developed to accommodate for voice traffic. This has changed, as people now use their phones to look at videos of cats. The transmission speed has become a bigger concern, but there is also another aspect. Voice calls usually use something called circuit switching. They would require a certain type of hardware. Data transfers usually use something called packet switching. They require a different type of hardware. Can you spot the problem?
Since the majority of traffic is now of the packet switched type, there is strong incentive to migrate everything over to the same hardware. You’ve probably heard about voice over IP (VoIP). That’s the general idea.
The newest arrival to the scene of cell phone standards is LTE. It’s the 4G everybody’s been talking about. The good thing about it is that a lot of people are saying they’re going to use it. Who knows? The world might make up its mind this time. Another good thing about it is that it’s very fast. We’re talking about more than 100 Mbit/s here. And that’s where we stand right about now.
Today, the number of our connections is growing at an exponential rate, and it’s never been easier to talk to someone on the other end of the globe. We grew up in this new era – the era of cell phones and the internet. And maybe we’ve become spoiled. I was traveling to Boston a few weeks ago, and my cell phone had no coverage. Scary, isn’t it? It’s not something that would kill me, but the thought is nevertheless a bit troubling. What would happen if someone pulled the plug?