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We are about to begin the transition from the present cellular standard 4G LTE to the next generation, 5G. As in the past, most people will wonder, “What does 5G mean to me, and what is LTE anyway?” After all, if you can make your connection reliably and you can send and receive data at reasonable speeds, why should you really care? Many of you will not, and some will only care because the latest mobile device has become a status symbol; but all of us will gain a significant data communication speed increase when we get access to 5G networks and compatible devices, and our world will begin to change rapidly. If you are interested in the Internet of Things (IoT), you ain’t seen nothing yet!
To get a better understanding of what 5G is going to mean, let’s take a quick look back at the history of mobile communications. In the ‘70s, if you wanted to communicate with someone who was not in your presence (and you were not near a land line), you had to use a mobile plain old telephone service (POTS) network. This service was first offered by AT&T in the late ‘40s and was called a mobile telephone service (MTS). These were push-to-talk systems; one person would hold in the microphone button and speak and then say “over” and then release the mic button, and the other person would have his turn. If you wanted to communicate from your car, you could try to get a mobile phone, but as each area had only very limited communications receiver/transmitters to communicate with mobile phone users, the number of devices it could service without the devices interfering with each other was extremely limited. This was basically mono communications (half-duplex) rather than cellular as we know it today. The waiting list to get mobile phone access was literally years long.
Of course, there was ham radio two-way communications as well as range-limited citizens band (CB radio); these also required taking turns to talk. I tried all of these. I tried to put my name on the list for a mobile connection in the Washington, D.C. area where I lived at the time; the waiting list was so long there was a list to get on the list and the cost to use such a device was astronomical. I did have a ham radio license, but that was a hobby and you could only communicate with others who were ham radio operators. CB was similar, but much shorter range due to lower power and limited transmission frequencies.
I ended up doing what many who needed to have some level of mobile communications did at the time and that was get a pager or beeper (Figure 1). You had this small paging device and if your family or office needed you they would call a phone number and beep you and you would find a pay phone and call them to see what was up. Eventually, the paging device allowed you to receive a short text message but still only offered very limited communication options. Things improved over the next few decades. Companies such as Motorola entered the arena and the full duplex voice (no pushing a mic button to speak) and cellular hand-off from tower to tower system was born.
The first true cellular networks or first generation (1G) became available in 1977 in Chicago. This revolutionary technology still used analog, but it seamlessly allowed the user to automatically switch from tower to tower as you traveled from area to area. In fact, one of my associates back then at DynaChem was one of the first to get his hands on a cellular phone. It was a black box the size of a cigar box mounted in the trunk of your car with a standard old-school telephone handset mounted on your dash. We were all envious (Figure 2).
Before major improvements could be made, the infant industry first had to have a frequency assigned— the cellular band, so to speak. It took the FCC 11 years to approve the AT&T proposal and authorize commercial use of the requested 824 MHz band for cellular use. Once that happened, cellular networks began to bloom globally. The phones were large, not usually portable, analog and expensive to buy—typically a few thousand dollars. Costs were also quite expensive per minute of use.
To read the full version of this article which appeared in the May 2018 issue of PCB007 Magazine, click here.