Mobile telephones are a near-ubiquitous feature of modern life. To say that mobile technology has fundamentally altered the human experience would not be an overstatement. Psychologists, sociologists, and neuroscientists are only now beginning to understand the long-term impact of mobile phones on human society and the human individual. Modern cell phones are essentially pocket computers. They enable instant communication and access to the internet from nearly everywhere on the planet. They are changing the way we talk, find love, work, and argue. They impact our ability to concentrate, increase our access to information, and generate entirely novel means of expression.
Mobile telephones are immensely popular. Around 78 percent of the world’s population is estimated to own a smartphone. In 2021, there were around 6.4 billion registered smartphone users. Engineers have played a huge role in the development of the mobile phone. Telecoms engineers, electronics engineers, civil engineers, and aerospace engineers have all contributed – and continue to contribute – toward the performance and ubiquity of this technology.
This article takes a close look at some of the engineering aspects of mobile phone technology and aims to give some context to these areas. It covers not only the areas of technology involved but also the engineers that helped to develop them.
Cellular Radio Service
Mobile phones would be nearly useless without being connected to a cellular network – otherwise known as a cellular radio service. This is the network that allows mobile phone users to make calls, send texts, and use mobile data. It also enables the location of individual devices through triangulation. The development of the first cellular network was an absolutely huge telecoms engineering feat.
A cellular network is a radio service that is distributed among cells. Each cell includes a fixed location transceiver known as a base station. A single cell served by a base station is usually around 9 to 21 miles squared depending on the kind of terrain that it serves. Mobile phone users are able to hop between cells automatically, which means that they are able to utilize an entire network. The creation of a working cell network is a good example of why sound engineering management is important. Without good engineering collaboration and management, isolated systems would pop up – rendering each individual system rather useless to users that want to travel with their devices. This means you would benefit from studying a master of engineering management program, as it combines the two most needed skillsets: engineering and management.
The development of this system involved the creation of an entirely new kind of automated communication between mobile devices and transceivers.
If you are making a call from within a cell and begin to move towards the edge of that cell’s coverage, the transceiver will send an automated request to an MSC – or Mobile Switching Centre – and automatically switch sent and received signals to a new transceiver without you even noticing. This technology is truly a feat of large-scale telecoms engineering.
The concept behind the cellular radio network can be traced all the way back to 1947 – long before the technology to actually engineer such a network existed. Doug Ring, an engineer at Bell Laboratories, authored a never-released technical memorandum in which he very accurately envisioned the way a mobile telephone network could work. Ring pointed out that a system of intersecting cells could provide broad coverage to vehicle-based mobile communications devices. He even made a sketch of his proposal – which seems incredibly well-conceived in hindsight. Today, 95 percent of the world is covered by mobile networks. This is a truly remarkable development: from conception in a memorandum to near complete adoption in just over 70 years. Doug may not have truly known just how influential his idea would become.
The first mobile phones were the size of bricks and needed to be connected to a power source. Despite this, they were actually marvels of miniaturization. The miniaturization of electronic components is behind nearly every advancement in mobile phone technology. The idea of making components smaller in order to increase capability and functionality is nothing new, but it was boosted hugely by two inventions.
The transistor, invented in 1947, allowed engineers to do away with costly, large valves when moderating and altering currents. This produced a new wave of devices that could fit into a pocked. The transistor revolutionized personal, battery-powered devices. Transistor radios allowed people to take music with them. Without the transistor, the mobile phone would never have been a possibility. The other invention that kickstarted modern miniaturization was the microchip. In 1959, the first patent for a tiny integrated circuit was filed by Jack Kilby of Texas Instruments. Microchips allow engineers to design complex circuits without relying on fragile wiring.
Miniaturization is an ongoing engineering concern. Packing more capability into a small space will always be the key to offering better mobile telephones to consumers.
Jack Kilby, the inventor of the microchip, deserves a special mention in the history of miniaturization. Early computers were limited by the sheer number of connections that needed to be made in order to increase capabilities. Almost any computer could be designed but only very basic models could be made small enough due to the ‘tyranny of numbers’.
When Jack Kilby joined Texas Instruments in 1958, he was excluded from the engineering team day in, day out due to his recent arrival. While the others were away on an all-expenses-paid holiday, Jack stayed in the office and set to work on a concept that would change computing forever and eventually facilitate the invention of mobile telephones. Jack’s idea was this: instead of composing circuits out of individual components that all needed individual wiring, why not simply integrate all of the components of a circuit onto an etched board? Kilby had single-handedly bought computing forward massively.
For his work on the microchip, Jack Kilby was awarded the Nobel Prize in Physics in the year 2000. President Bill Clinton, congratulating the now-aging engineer, wrote:
“You can take pride in the knowledge that your work will help to improve lives for generations to come.”
Although the first mobile phones were tethered to vehicles, cell devices only became truly mobile thanks to the development of effective rechargeable batteries. The batteries inside modern smartphones are a far cry from the 60-pound behemoths connected to early mobile phones in the 1980s. This is thanks to the development of Lithium Ion battery technology.
Lithium Ion batteries all share three main components: an electrolyte, an anode, and a cathode. An electrolyte provides electrons, an anode discharges them, and a cathode receives them. Lithium is found in the electrolyte, but not in the anode. This restricts capabilities. Today’s electronics engineers are working hard to create a viable Lithium anode. This is considered to be the ‘holy grail’ of battery development and would allow small batteries to offer huge amounts of power for large periods of time. Creating a safe Lithium anode is incredibly complex. Any breakthrough will impact not just mobile phones, but every area of electronics. As it stands, the Lithium Ionbattery is as good as it gets. Thankfully, these batteries are still a massive improvement over previous alkaline designs.
Nobel Prize winner M. Stanley Whittingham was the first person to come up with a working concept for a Lithium Ion battery. Born in Nottingham in the United Kingdom, Whittingham did most of his work in the United States. He discovered that a cathode made using Titanium Disulphide could house Lithium. On a molecular level, the Titanium contains spaces which perfectly attract and retain Lithium in a way that very few other materials do. Lithium is a chemical that willingly releases electrodes, making it perfect for use in batteries. Without Whittingham’s incredible chemical engineering breakthrough, the mobile phones of today would not have been able to stay charged for long, and they would have been very limited in capability. Although M. Stanley Whittingham published his first work on batteries in the 1970s, he remained influential in the development of power sources for many years to come.
Early mobile phones had no display at all. Much like when a person used a landline phone, a mobile user had to listen to tones in order to remember the number that they were typing. LCD displays were eventually integrated into devices, which massively improved functionality and paved the way for text messaging, mobile gaming, and a whole host of other innovations.
A huge leap forward occurred when touch screens were integrated into mobile phones. Touch screens allowed mobile engineers to do away with buttons altogether and dedicate the entire device to a multipurpose screen.
Interestingly, the touch screen can trace its roots all the way back to 1965. Eric Arthur Johnson – an engineer working at the Royal Radar Establishment in England – first conceived of such an interface while trying to work out ideas for a new kind of air traffic control device. He developed an idea based on the way in which capacitive screens can register the touch of a conductive surface. It was a long while before Johnson’s idea would make it into the telecommunications market. The first true touch screen on a mobile phone was released in 1992. The IBM Simon was a rudimentary smartphone that could just about operate as a device to send emails from. It has been described as the first time somebody had thought to integrate the capabilities of a computer into a handheld mobile device. It was not a success – largely due to the enormous cost of the handset and the limited availability of the internet.
Text messaging is not considered to be as significant an area of mobile engineering as it once was, but the fact remains that the invention of text messaging ushered in a new age of communication. The idea of sending a visual message between mobile devices turned the telecommunications industry upside down.
A 22-yea- old British engineer called Neil Papworth sent the first-ever text message on December 10th, 1992. It simply read ‘merry Christmas’. Papworth had cleverly used his computer to transmit a message to a colleague’s phone. He didn’t receive a reply because no mobile phone at the time was capable of text input. This may have been the first-ever incident of ghosting. Papworth’s invention only really caught on after the introduction of mobile phones that could use predictive text – using an inbuilt database of words to predict the message a person wanted to send based on their keystrokes.
These days, one of the big selling points advertised by mobile phone companies is the quality of the camera (or cameras) built into the devices that they sell. Modern mobile phones have incredibly powerful cameras that have been engineered using absolutely minute components. The first camera-equipped phone was released in 1999. The Kyocera Visual Phone VP 210 was only released in Japan and had dreadful picture quality. The concept took off, however, and the miniaturization of cameras for integration into mobile systems has continued at a startling pace.
The emergence of the camera-equipped phone owes a great deal to the French engineer Phillipe Kahn. Kahn was a serial tinkerer who had previously installed a server for sharing images to the internet in his home. During his wife’s 18-hour labor with their child, Kahn set about connecting his flip phone, his laptop, and his digital camera. Amazingly, he managed to scrape together a method for transmitting images over a mobile phone inside the hospital ward, sending out the first ever mobile transmitted image of his new baby mere seconds after it was born. It is unknown whether his wife thought this was a particularly noble endeavor as she struggled to give birth, but either way, it certainly was an act that had repercussions way outside of his marriage.
Kahn went on to found the company LightSurf, which was one of the earliest developers of integrated camera phones.