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Writer's pictureMary Reed

Wednesday, November 24, 2021 – Mobile Phones


Today I upgraded from an iPhone 8 to an iPhone 13. The photo shows the colors of the iPhone 13. I got the blue one. There was an early Black Friday promotion. My iPhone storage went from 64 MB to 128 MB. Mobile phones are still way too expensive and, of course, something we cannot live without. I have lived long enough to see much technological progress. I was ashamed to admit to a trainee at my job that there were not even calculators when I went to school. Technology can make a lot of things so much easier — and sometimes dangerous. I remember when my office got our first personal computer. There was one for the entire office, and we had to sign up to use it. I also remember the first time I forgot to save hours of work, putting my head down on my desk and crying. My first mobile phone was the iPhone 6. It came out in 2014, so I probably didn’t get one until 2015. That was six years ago. It seems like mobile phones have been around a lot longer than that, but I guess not. They are so much a part of our everyday lives; it is hard to believe we have had them such a short time. Keeping up on social media, watching videos, sending and receiving emails, texting, playing games, GPS, shopping, banking — there really is no end to all the things we now do on our mobile phones. Let’s learn more about them.

According to Wikipedia, a mobile phone, cellular phone, cell phone, cellphone, handphone or hand phone — sometimes shortened to simply mobile, cell or just phone — is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network. Modern mobile telephone services use a cellular network architecture and, therefore, mobile telephones are called cellular telephones or cell phones in North America. In addition to telephony, digital mobile phones or 2G support a variety of other services, such as text messaging, MMS, email, internet access, short-range wireless communications — infrared, Bluetooth, business applications, video games and digital photography. Mobile phones offering only those capabilities are known as feature phones; mobile phones which offer greatly advanced computing capabilities are referred to as smartphones.


From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion; enough to provide one for every person on Earth. In the first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple and Huawei; smartphone sales represented 78% of total mobile phone sales. For feature phonesslang: "dumbphones" — as of 2016, the top-selling brands were Samsung, Nokia and Alcatel.

Deutsche Reichsbahn or German National Railway

History


Predecessors

In 1908, Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and Power Company claimed to have developed a wireless telephone. They were accused of fraud and the charge was then dropped, but they do not seem to have proceeded with production. Beginning in 1918, the German railroad system tested wireless telephony on military trains between Berlin and Zossen. In 1924, public trials started with telephone connection on trains between Berlin and Hamburg. In 1925, the company Zugtelephonie AG was founded to supply train telephony equipment and, in 1926, telephone service in trains of the Deutsche Reichsbahn and the German mail service on the route between Hamburg and Berlin was approved and offered to first-class travelers.

“Wireless Telephony” by Karl Arnold 1926

Fiction anticipated the development of real-world mobile telephones. In 1906, the English caricaturist Lewis Baumer published a cartoon in Punch magazine entitled "Forecasts for 1907" in which he showed a man and a woman in London's Hyde Park each separately engaged in gambling and dating on wireless telephony equipment. Then, in 1926, the artist Karl Arnold created a visionary cartoon about the use of mobile phones in the street in the picture "Wireless Telephony" published in the German satirical magazine Simplicissimus.

GE portable walkie talkie radios


The Second World War made military use of radio telephony links. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Early devices were bulky and consumed large amounts of power; the network supported only a few simultaneous conversations. Modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications.







First mobile telephone 1946

In the United States, engineers from Bell Labs began work on a system to allow mobile users to place and receive telephone calls from automobiles, leading to the inauguration of mobile service on June 17, 1946 in St. Louis, Missouri. Shortly after, AT&T offered Mobile Telephone Service. A wide range of mostly incompatible mobile telephone services offered limited coverage areas and only a few available channels in urban areas. As calls were transmitted as unencrypted analog signals, they could be eavesdropped on by anyone with radio equipment that could receive those frequencies. The introduction of cellular technology — which allowed reuse of frequencies many times in small adjacent areas covered by relatively low-powered transmitters — made widespread adoption of mobile telephones economically feasible.

In the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental pocket-sized communications radio. The weight of one model — presented in 1961 — was only 70 g and could fit on a palm. However, in the USSR the decision at first to develop the system of the automobile "Altai" phone was made.


In 1965, the Bulgarian company "Radioelektronika" presented a mobile automatic phone combined with a base station at the Inforga-65 international exhibition in Moscow. Solutions of this phone were based on a system developed by Leonid Kupriyanovich. One base station connected to one telephone wire line could serve up to 15 customers.


The advances in mobile telephony can be traced in successive generations from the early "0G" services like MTS and its successor Improved Mobile Telephone Service, to first-generation (1G) analog cellular network, second-generation (2G) digital cellular networks, third-generation (3G) broadband data services to the state-of-the-art, fourth-generation (4G) native-IP networks.

Top of a cellular radio tower

Underlying technology

The development of metal-oxide-semiconductor (MOS) large-scale integration (LSI) technology, information theory and cellular networking led to the development of affordable mobile communications. There was a rapid growth of wireless telecommunications towards the end of the 20th century, primarily due to the introduction of digital signal processing in wireless communications, driven by the development of low-cost, very large-scale integration (VLSI) RF CMOS (radio-frequency complementary MOS) technology.


MOSFET, showing gate (G), body (B), source (S) and drain (D) terminals.

The development of cell phone technology was enabled by advances in MOSFET (metal-oxide-silicon field-effect transistor) semiconductor device fabrication. The MOSFET (MOS transistor) — invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959 — is the basic building block of modern cell phones. MOSFET scaling — where MOS transistors get smaller with decreasing power consumption — enabled very large-scale integration (VLSI) technology with MOS transistor counts in integrated circuit chips increasing at an exponential pace, as predicted by Moore's law. Continuous MOSFET scaling eventually made it possible to build portable cell phones. A typical modern smartphone is built from billions of tiny MOSFETs as of 2019, used in integrated circuits such as microprocessors and memory chips, as power devices and as thin-film transistors (TFTs) in mobile displays.

Advances in MOSFET power electronic technology also enabled the development of digital wireless mobile networks, which are essential to modern cell phones. The wide adoption of power MOSFET, LDMOS (lateral diffused MOS) and RF CMOS (radio frequency CMOS) devices led to the development and proliferation of digital wireless mobile networks by the 1990s, with further advances in MOSFET technology leading to increasing bandwidth during the 2000s. Most of the essential elements of wireless mobile networks are built from MOSFETs, including the mobile transceivers, base station modules, routers, RF power amplifiers, telecommunication circuits, RF circuits and radio transceivers in networks such as 2G, 3G and 4G.

Another important enabling factor was the lithium-ion battery, which became indispensable as an energy source for cell phones. The lithium-ion battery was invented by John Goodenough, Rachid Yazami and Akira Yoshino in the 1980s and commercialized by Sony and Asahi Kasei in 1991.


Early services


MTS

In 1949, AT&T commercialized Mobile Telephone Service. From its start in St. Louis, Missouri, in 1946, AT&T introduced Mobile Telephone Service to 100 towns and highway corridors by 1948. Mobile Telephone Service was a rarity with only 5,000 customers placing about 30,000 calls each week. Calls were set up manually by an operator, and the user had to depress a button on the handset to talk and release the button to listen. The call subscriber equipment weighed about 80 pounds.


Subscriber growth and revenue generation were hampered by the constraints of the technology. Because only three radio channels were available, only three customers in any given city could make mobile telephone calls at one time. Mobile Telephone Service was expensive, costing $15 per month, plus $0.30–0.40 per local call, equivalent to — in 2012 US dollars — about $176 per month and $3.50–4.75 per call.


In the UK, there was also a vehicle-based system called "Post Office Radiophone Service," which was launched around the city of Manchester in 1959, and although it required callers to speak to an operator, it was possible to be put through to any subscriber in Great Britain. The service was extended to London in 1965 and other major cities in 1972.


IMTS

AT&T introduced the first major improvement to mobile telephony in 1965, giving the improved service the obvious name of Improved Mobile Telephone Service. IMTS used additional radio channels, allowing more simultaneous calls in a given geographic area, introduced customer dialing, eliminating manual call setup by an operator and reduced the size and weight of the subscriber equipment.


Despite the capacity improvement offered by IMTS, demand outstripped capacity. In agreement with state regulatory agencies, AT&T limited the service to just 40,000 customers systemwide. In New York City, for example, 2,000 customers shared just 12 radio channels and typically had to wait 30 minutes to place a call.

Radson radio telephone

Radio Common Carrier

Radio Common Carrier or RCC was a service introduced in the 1960s by independent telephone companies to compete against AT&T's IMTS. RCC systems used paired UHF 454/459 MHz and VHF 152/158 MHz frequencies near those used by IMTS. RCC-based services were provided until the 1980s when cellular AMPS systems made RCC equipment obsolete.


Some RCC systems were designed to allow customers of adjacent carriers to use their facilities, but equipment used by RCCs did not allow the equivalent of modern "roaming" because technical standards were not uniform. For example, the phone of an Omaha, Nebraska–based RCC service would not be likely to work in Phoenix, Arizona. Roaming was not encouraged, in part, because there was no centralized industry billing database for RCCs. Signaling formats were not standardized. For example, some systems used two-tone sequential paging to alert a mobile of an incoming call. Other systems used DTMF or dual-tone multi-frequency signaling. Some used Secode 2805, which transmitted an interrupted 2805 Hz tone — similar to IMTS signaling — to alert mobiles of an offered call. Some radio equipment used with RCC systems was half-duplex, push-to-talk LOMO equipment such as Motorola handhelds or RCA 700-series conventional two-way radios. Other vehicular equipment had telephone handsets and rotary dials or pushbutton pads and operated full duplex like a conventional wired telephone. A few users had full-duplex briefcase telephones — radically advanced for their day.

Other services

In 1969 Penn Central Railroad equipped commuter trains along the 220-mile New York-Washington route with special pay phones that allowed passengers to place telephone calls while the train was moving. The system reused six frequencies in the 450 MHz band in nine sites.


In the UK, Channel Islands and elsewhere the "Rabbit" phone system was briefly used, being a hybrid of "cell" base stations and handsets. One major limitation was that you had to be less than 300 feet — closer with buildings — from a base due to power limitations on a portable device. With modern technology a similar variant is being considered for Apple's new 4G "smart watch" so it can be used in large events in a broadly similar way to a femtocell.

Receiver for Nordic Mobile Telephone or NMT

European mobile radio networks

In Europe, several mutually incompatible mobile radio services were developed.


In 1966 Norway had a system called OLT which was manually controlled. Finland's ARP, launched in 1971, was also manual as was the Swedish MTD. All were replaced by the automatic NMT or Nordic Mobile Telephone system in the early 1980s.


In July 1971 Readycall was introduced in London by Burndept after obtaining a special concession to break the post office monopoly to allow selective calling to mobiles of calls from the public telephone system. This system was available to the public for a subscription of £16 month. A year later the service was extended to two other UK towns.


West Germany had a network called A-Netz launched in 1952 as the country's first public commercial mobile phone network. In 1972 this was displaced by B-Netz which connected calls automatically.

Douglas H. Ring at Bell Labs in early 1940s

Cellular concept

In December 1947, Bell Labs engineers Douglas H. Ring and W. Rae Young 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 Bell Labs engineer Amos E. Joel, Jr. 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 et al.

1956 – SRA/Ericsson MTA weighed 88 pounds

Emergence of automated systems

The first fully automated mobile phone system for vehicles was launched in Sweden in 1956. Named MTA — Mobiltelefonisystem A — it allowed calls to be made and received in the car using a rotary dial. The car phone could also be paged. Calls from the car were direct dial, whereas incoming calls required an operator to locate the nearest base station to the car. It was developed by Sture Laurén and other engineers at Televerket network operator. Ericsson provided the switchboard while Svenska Radioaktiebolaget or SRA and British Marconi Co. provided the telephones and base station equipment. MTA phones consisted of vacuum tubes and relays, weighing 88 pounds. In 1962, an upgraded version called Mobile System B or MTB was introduced. This was a push-button telephone and used transistors and DTMF signaling to improve its operational reliability. In 1971 the MTD version was launched, opening for several different brands of equipment and gaining commercial success. The network remained open until 1983 and still had 600 customers when it closed.


In 1958 development began on a similar system for motorists in the USSR. The "Altay" national civil mobile phone service was based on Soviet MRT-1327 standard. The main developers of the Altay system were the Voronezh Science Research Institute of Communications and the State Specialized Project Institute. In 1963 the service started in Moscow, and by 1970 was deployed in 30 cities across the USSR. Versions of the Altay system are still in use today as a trunking system in some parts of Russia.

In 1959 a private telephone company in Brewster, Kansas, the S&T Telephone Co. — still in business today — with the use of Motorola Radio Telephone equipment and a private tower facility, offered to the public mobile telephone services in that local area of northwest Kansas. This system was a direct dial-up service through their local switchboard and was installed in many private vehicles including grain combines, trucks and automobiles. For some as yet unknown reason, the system, after being placed online and operated for a very brief time period, was shut down. The management of the company was immediately changed, and the fully operable system and related equipment was immediately dismantled in early 1960, not to be seen again.


In 1966, Bulgaria presented the pocket mobile automatic phone RAT-0,5 combined with a base station RATZ-10 on Interorgtechnika-66 international exhibition. One base station connected to one telephone wire line could serve up to six customers.


One of the first successful public commercial mobile phone networks was the ARP network in Finland, launched in 1971. Posthumously, ARP is sometimes viewed as a zero generation cellular network, being slightly above previous proprietary and limited coverage networks.

Martin Cooper world’s first mobile phone call 1973

Handheld mobile phone

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 2.4 pounds and measured 9.1 by 5.1 by 1.8 inches. The prototype offered a talk time of just 30 minutes and took 10 hours to recharge.


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 successfully pushed Motorola to develop wireless communication products that would be small enough to use anywhere and participated in the design of the cellular phone.

Motorola DynaTAC 8000X TACS mobile phone

1G – analog cellular

The first automatic analog cellular systems ever deployed were Nippon Telephone and Telegraph Corp.’s or NTT's system first used in 1979 for car phones in Tokyo — and later the rest of the country of Japan, and the NMT system which was released in the Nordic countries in 1981.

The first analog cellular system widely deployed in North America was the Advanced Mobile Phone System or AMPS. It was commercially introduced in the Americas on October 13, 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 scheme and required significant amounts of wireless spectrum to support.


On March 6, 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 30 minutes and took 10 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 in 1990, and AMPS service was shut down by most North American carriers by 2008.


In February 1986 Australia launched its Cellular Telephone System by Telecom Australia. Peter Reedman was the first Telecom customer to be connected on January 6, 1986, along with five other subscribers as test customers prior to the official launch date of February 28.

Ericsson s868 GSM mobile phone

2G – digital cellular

In the 1990s, the “second-generation” mobile phone systems emerged. Two systems competed for supremacy in the global market: the European developed GSM standard and the U.S. developed CDMA standard. These differed from the previous generation by using digital instead of analog transmission and also fast out-of-band phone-to-network signaling. The rise in mobile phone usage as a result of 2G was explosive, and this era also saw the advent of prepaid mobile phones.


In 1991 the first GSM network — Radiolinja — launched in Finland. In general, the frequencies used by 2G systems in Europe were higher than those in America, though with some overlap. For example, the 900 MHz frequency range was used for both 1G and 2G systems in Europe, so the 1G systems were rapidly closed down to make space for the 2G systems. In America the IS-54 standard was deployed in the same band as AMPS and displaced some of the existing analog channels.

IBM Simon, the world’s first smartphone

In 1993, IBM Simon was introduced. This was possibly the world's first smartphone. It was a mobile phone, pager, fax machine and PDA all rolled into one. It included a calendar, address book, clock, calculator, notepad, email and a touchscreen with a QWERTY keyboard. The IBM Simon had a stylus, used to tap the touch screen. It featured predictive typing that would guess the next characters as you tapped. It had applications or at least a way to deliver more features by plugging a PCMCIA 1.8 MB memory card into the phone. Coinciding with the introduction of 2G systems was a trend away from the larger "brick" phones toward tiny 3.5–7.1 oz. hand-held devices. This change was possible not only through technological improvements such as more advanced batteries and more energy-efficient electronics, but also because of the higher density of cell sites to accommodate increasing usage. The latter meant that the average distance transmission from phone to the base station shortened, leading to increased battery life while on the move.


The second generation introduced a new variant of communication called SMS or text messaging. It was initially available only on GSM networks but spread eventually on all digital networks. The first machine-generated SMS message was sent in the UK on December 3, 1992 followed in 1993 by the first person-to-person SMS sent in Finland. The advent of prepaid services in the late 1990s soon made SMS the communication method of choice among the young, a trend which spread across all ages.


2G also introduced the ability to access media content on mobile phones. In 1998 the first downloadable content sold to mobile phones was the ring tone, launched by Finland's Radiolinja, now Elisa. Advertising on the mobile phone first appeared in Finland when a free daily SMS news headline service was launched in 2000, sponsored by advertising.


Mobile payments were trialed in 1998 in Finland and Sweden where a mobile phone was used to pay for a Coca-Cola vending machine and car parking. Commercial launches followed in 1999 in Norway. The first commercial payment system to mimic banks and credit cards was launched in the Philippines in 1999 simultaneously by mobile operators Globe and Smart.


The first full internet service on mobile phones was introduced by NTT DoCoMo in Japan in 1999.

iPhone 3GS

3G – mobile broadband

As the use of 2G phones became more widespread and people began to use mobile phones in their daily lives, it became clear that demand for data — such as access to browse the internet — was growing. Further, experience from fixed broadband services showed there would also be an ever-increasing demand for greater data speeds. The 2G technology was nowhere near up to the job, so the industry began to work on the next generation of technology known as 3G. The main technological difference that distinguishes 3G technology from 2G technology is the use of packet switching rather than circuit switching for data transmission. In addition, the standardization process focused on requirements more than technology — 2 Mbit/s maximum data rate indoors, 384 kbit/s outdoors, for example.


Inevitably this led to many competing standards with different contenders pushing their own technologies, and the vision of a single unified worldwide standard looked far from reality. The standard 2G CDMA networks became 3G compliant with the adoption of Revision A to EV-DO, which made several additions to the protocol while retaining backwards compatibility:


- Introduction of several new forward link data rates that increase the maximum burst rate

from 2.45 Mbit/s to 3.1 Mbit/s.

- Protocols that would decrease connection establishment time.

- Ability for more than one mobile to share the same time slot.

- Introduction of QoS flags.


All these were put in place to allow for low latency, low bit rate communications such as VoIP.

The first pre-commercial trial network with 3G was launched by NTT DoCoMo in Japan in the Tokyo region in May 2001. NTT DoCoMo launched the first commercial 3G network on October 1, 2001, using the WCDMA technology. In 2002 the first 3G networks on the rival CDMA2000 1xEV-DO technology were launched by SK Telecom and KTF in South Korea, and Monet in the US. Monet has since gone bankrupt. By the end of 2002, the second WCDMA network was launched in Japan by Vodafone KK, now Softbank. European launches of 3G were in Italy and the UK by Three/Hutchison group on WCDMA. 2003 saw a further eight commercial launches of 3G, six more on WCDMA and two more on the EV-DO standard.

The high connection speeds of 3G technology enabled a transformation in the industry: for the first time, media streaming of radio and even television content to 3G handsets became possible, with companies such as RealNetworks and Disney among the early pioneers in this type of offering.


In the mid-2000s, an evolution of 3G technology began to be implemented, namely High-Speed Downlink Packet Access or HSDPA. It is an enhanced 3G mobile telephony communications protocol in the High-Speed Packet Access family which allows networks based on Universal Mobile Telecommunications System to have higher data transfer speeds and capacity. Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.0 Mbit/s.


By the end of 2007, there were 295 million subscribers on 3G networks worldwide, which reflected 9% of the total worldwide subscriber base. About two-thirds of these were on the WCDMA standard and one-third on the EV-DO standard. The 3G telecoms services generated over $120 billion of revenues during 2007, and at many markets, the majority of new phones activated were 3G phones. In Japan and South Korea, the market no longer supplies phones of the second generation.


Although mobile phones had long had the ability to access data networks such as the internet, it was not until the widespread availability of good quality 3G coverage in the mid-2000s that specialized devices appeared to access the mobile web. The first such devices — known as "dongles" — plugged directly into a computer through the USB port. Another new class of device appeared subsequently, the so-called "compact wireless router" such as the Novatel MiFi, which makes 3G internet connectivity available to multiple computers simultaneously over Wi-Fi, rather than just to a single computer via a USB plug-in.

Such devices became especially popular for use with laptop computers due to the added portability they bestow. Consequently, some computer manufacturers started to embed the mobile data function directly into the laptop, so a dongle or MiFi wasn't needed. Instead, the SIM card could be inserted directly into the device itself to access the mobile data services. Such 3G-capable laptops became commonly known as "netbooks." Other types of data-aware devices followed in the netbook's footsteps. By the beginning of 2010, E-readers — such as the Amazon Kindle and the Nook from Barnes & Noble — had already become available with embedded wireless internet, and Apple had announced plans for embedded wireless Internet on its iPad tablet devices later that year.

4G – native IP networks

By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications like streaming media. Consequently, the industry began looking to data-optimized 4th-generation technologies, with the promise of speed improvements up to 10-fold over existing 3G technologies. The first two commercially available technologies billed as 4G were the WiMAX standard offered in the U.S. by Sprint and the LTE standard, first offered in Scandinavia by TeliaSonera.


One of the main ways in which 4G differed technologically from 3G was in its elimination of circuit switching, instead employing an all-IP network. Thus, 4G ushered in a treatment of voice calls just like any other type of streaming audio media, using packet switching over internet, local area networks or LAN, wide area networks or WAN networks via Voice over Internet Protocol or VoIP.

5G – cellular mobile communications

"5G" is the next version of cellular mobile telephone standards. The 5G standards include millimeter-band radio spectrum to allow data speeds up to 1 gigabit per second and reduce latency — the processing time to handle a data transmission — between handset and network to a few milliseconds. 5G standards also include low-band and mid-band spectrum similar to existing networks. Telephone companies started introducing 5G technology in 2019.




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