Miguel Dajer, Director US Wireless Research Institute, Futurewei Technologies
Published: 12 Apr 2019
CTN Issue: March 2019
A note from the editor:
This month we celebrate the birthday of the thing that has kept many of us in a job for years now, the mobile phone. Miguel (for full disclosure, my real life boss) wrote a nice article for an internal magazine and gave me permission to share it all with you. With all the hype about 5G and connecting everything, it is a good idea to spend a little time remembering where and why it all started. Anyone old enough to remember the birth of this industry is welcome to contact us with their reminiscences. Maybe we will do a follow up article if there is enough interest. In the meantime, enjoy this short stroll down memory lane.
The Mobile Phone: 46 Years Old and Going Strong
April 3rd is a historical date for the mobile industry. With the help of Wikipedia and some colleagues I have patched together some historical tidbits related to cellular communications. More importantly, these historical points show how a dream can become reality through research and innovation. The technologies to make cellular communications practical took decades to develop, but scientist and engineers pursued the vision of communication without wires because it was thought to be a fundamental breakthrough to change the way in which society functions. The dream of cellular ubiquitous communication was present for decades until it started to become reality in 1973. Today, the world is wirelessly connected and many companies have benefited greatly from the boom that it has created, so to remember the pioneers that laid the ground work is only fitting. Also, as we prepare for 5G it is sobering to see how this business emerged and the efforts required to make it successful. In this article we are really celebrating the first call that Martin Cooper of Motorola placed to his colleague and competitor at Bell Labs Joel Engel. These two men and their competing companies would eventually share in the challenges and victories, but back then this friendly but fierce competition between two teams helped forge the foundation of this industry.
Prior to 1973, mobile telephony was limited to phones installed in cars and other vehicles. Motorola was the first company to produce a handheld mobile phone. On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first mobile telephone call from handheld subscriber equipment, placing a call to Dr. Joel S. Engel of Bell Labs, his rival. The prototype handheld phone used by Dr. Cooper weighed 1.1 kilograms (2.4 lb.) and measured 23 by 13 by 4.5 centimeters (9.1 by 5.1 by 1.8 in). The prototype offered a talk time of just 30 minutes and took 10 hours to re-charge. The story goes that Martin was nearly hit by a car crossing the road with his new phone! Apparently they have always been distracting devices.
John F. Mitchell, Motorola's chief of portable communication products and Cooper's boss in 1973, played a key role in advancing the development of handheld mobile telephone equipment. Mitchell pushed Motorola into developing wireless communication products that would be small enough to use anywhere and participated in the design of the cellular phone.
In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs engineers, proposed hexagonal cells for mobile phones in vehicles. At this stage, the technology to implement these ideas did not exist, nor had the frequencies been allocated. Two decades would pass before Richard H. Frenkiel, Joel S. Engel and Philip T. Porter of Bell Labs expanded the early proposals into a much more detailed system plan. It was Porter who first proposed that the cell towers use the now-familiar directional antennas to reduce interference and increase channel reuse. Porter also invented the dial-then-send method used by all cell phones to reduce wasted channel time.
In all these early examples, a mobile phone had to stay within the coverage area serviced by one base station throughout the phone call, i.e. there was no continuity of service as the phones moved through several cell areas. The concepts of frequency reuse and handoff, as well as a number of other concepts that formed the basis of modern cell phone technology, were described in the late 1960s, in papers by Frenkiel and Porter. In 1970 Amos E. Joel, Jr., a Bell Labs engineer, invented a "three-sided trunk circuit" to aid in the "call handoff" process from one cell to another. His patent contained an early description of the Bell Labs cellular concept, but as switching systems became faster, such a circuit became unnecessary and was never implemented in a system.
A cellular telephone switching plan was described by Fluhr and Nussbaum in 1973, and a cellular telephone data signaling system was described in 1977 by Hachenburg and others.
As we know, newer technologies has been developed and rolled out in a series of waves or generations. The "generation" terminology only became widely used when 3G was launched, but is now used retroactively when referring to the earlier systems.
The first analog cellular system widely deployed in North America was the Advanced Mobile Phone System (AMPS).It was commercially introduced in the Americas in 13 October 1983, Israel in 1986, and Australia in 1987. AMPS was a pioneering technology that helped drive mass market usage of cellular technology, but it had several serious issues by modern standards. It was unencrypted and easily vulnerable to eavesdropping via a scanner; it was susceptible to cell phone "cloning" and it used a Frequency-division multiple access (FDMA) scheme and required significant amounts of wireless spectrum to support.
On 6 March 1983, the DynaTAC 8000X mobile phone launched on the first US 1G network by Ameritech. It cost $100M to develop, and took over a decade to reach the market.The phone had a talk time of just thirty-five minutes and took ten hours to charge. Consumer demand was strong despite the battery life, weight, and low talk time, and waiting lists were in the thousands.
Many of the iconic early commercial cell phones such as the Motorola DynaTAC Analog AMPS were eventually superseded by Digital AMPS (D-AMPS) in 1990, and AMPS service was shut down by most North American carriers by 2008.
The rest of the story is still being written, today we have 5G and foldable phones, and scientist are already talking about 6G; it is clear that the industry and its applications are just starting, with so many more vertical markets still to be created, and so many wonderful research to be done. Not only analog voice transmission, but the cellular concept itself is being gradually replaced by a more user centric system. All of the fundamental technologies that made this industry have faded and been replaced but the vision of the people who made the original cellular system remains and is worth raising a glass to. Happy birthday cellular!
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