History of mobile phones
Content
History of mobile phones
The history of mobile phones begins with early efforts to develop mobile telephony concepts using two-way radios and continues through emergence of modern mobile phones and associated services. Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held mobile radio devices have been available since 1973. Mobile phone history is often divided into generations (first, second, third and so on) to mark significant step changes in capabilities as the technology improved over the years. In Europe, radio telephony was first used on the first-class passenger trains between Berlin and Hamburg in 1926. At the same time, radio telephony was introduced on passenger airplanes for air traffic security. Later radio telephony was introduced on a large scale in German tanks during the Second World War. In all of these cases the service was confined to specialists that were trained to use the equipment. In the early 1950s ships on the Rhine were among the first to use radio telephony with an untrained end customer as a user. However it was the 1940s onwards that saw the . Motorola developed a backpacked two-way radio, the Walkie-Talkie and a large hand-held two-way radio for the US military. This battery powered "Handie-Talkie" (HT) was about the size of a man's forearm. In 1946 in St. Louis, the Mobile Telephone Service was introduced In 1964 Improved Mobile Telephone Service was introduced with additional channels and more automatic handling of calls to the public switched telephone network. Even the addition of radio channels in three bands was insufficient to meet demand for vehicle-mounted mobile radio systems. In 1969, a patent for a wireless phone using an acoustic coupler for incoming calls was issued in US Patent Number 3,449,750 to George Sweigert of Euclid, Ohio on June 10, 1969, but did not include dialing a number for outgoing calls.
Emergence of commercial mobile phone services
Alongside the early developments outlined above, a different technology was also growing in popularity. Two-way mobile radios (known as mobile rigs) were used in vehicles such as taxicabs, police cruisers, and ambulances, but were not mobile phones, because they were not connected to the telephone network. The first fully automated mobile phone system for vehicles was launched in Sweden in 1960. Named MTA (Mobile Telephone system A), it allowed calls to be made and received in the car using a rotary dial. 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 (0G) cellular network, being slightly above previous proprietary and limited coverage networks.
Handheld cell phone
Dr. Martin Cooper of Motorola, made the first US analogue mobile phone call on a larger prototype model in 1973. This is a reenactment in 2007
On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first analogue mobile phone call using a heavy prototype model.
First generation: Cellular networks
The technological development that distinguished the First Generation mobile phones from the previous generation was the use of tramsfer calls. The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979. The initial launch network
covered the full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nation-wide 1G network.
Analog Motorola DynaTAC 8000X Advanced Mobile Phone System mobile phone as of 1983
Several other countries also launched 1G networks in the early 1980s including the UK, Mexico and Canada. A two year trial started in 1981 in Baltimore and Washington DC with 150 users and 300 Motorola DynaTAC pre-production phones. This took place on a seven tower cellular network that covered the area. The DC area trial turned into a commercial services in about 1983 with fixed cellular car phones also built by Motorola. They later added the 8000X to their Cellular offerings. A similar trial and commercial launch also took place in Chicago by Ameritech in 1983 using the famous first hand-held mobile phone Motorola DynaTAC. AT&T's 1971 proposal for Advanced Mobile Phone System (AMPS) was approved by the FCC in 1982 and frequencies were allocated in the 824±894 MHz band.[5] Analog AMPS was superseded by Digital AMPS in 1990. In 1984, Bell Labs developed modern commercial cellular technology (based, to a large extent, on the Gladden, Parelman Patent), which employed multiple, centrally controlled base stations (cell sites), each providing service to a small cell area. The sites were set up so that cells partially overlapped and different base stations operated using the same frequencies with little or no interference. Vodafone made the UK's first mobile call at a few minutes past midnight on 1 January 1985.[18] The technology in these early networks was pushed to the limit to accommodate increasing usage. The base stations and the mobile phones utilised variable transmission power, which allowed range and cell size to vary. As the system expanded and neared capacity, the ability to reduce transmission power allowed new cells to be added, resulting in more, smaller cells and
thus more capacity. The evidence of this growth can still be seen in the many older, tall cell site towers with no antennae on the upper parts of their towers. These sites originally created large cells, and so had their antennae mounted atop high towers; the towers were designed so that as the system expanded²and cell sizes shrank²the antennae could be lowered on their original masts to reduce range.
[edit] Second generation: Digital networks
Main articles: 2G, 2.5G, and 2.75G
Two 1991 GSM mobile phones with several AC adapters
In the 1990s, the 'second generation' (2G) mobile phone systems emerged, primarily using the GSM 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. Coinciding with the introduction of 2G systems was a trend away from the larger "brick" phones toward tiny 100±200g 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 whilst on the move.
Personal Handy-phone System mobiles and modems used in Japan around 1997 2003
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 3 December 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 amongst 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 trialled 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.
[edit] Third generation: High speed IP data networks and mobile broadband
Main article: 3G
As the use of 2G phones became more widespread and people began to utilize mobile phones in their daily lives, it became clear that demand for data services (such as access to the internet) was growing. Furthermore, 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.[19] 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 whilst retaining backwards compatibility:
y y y y
the 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. the ability for more than one mobile to share the same time slot. the introduction of QoS flags.
All these were put in place to allow for low latency, low bit rate communications such as VoIP.[20] 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 USA. 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 the Three/Hutchison group, on WCDMA. 2003 saw a further 8 commercial launches of 3G, six more on WCDMA and two more on the EV-DO standard. During the development of 3G systems, 2.5G systems such as CDMA2000 1x and GPRS were developed as extensions to existing 2G networks. These provide some of the features of 3G without fulfilling the promised high data rates or full range of multimedia services. CDMA20001X delivers theoretical maximum data speeds of up to 307 kbit/s. Just beyond these is the EDGE system which in theory covers the requirements for 3G system, but is so narrowly above these that any practical system would be sure to fall short. 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 [1], with companies such as RealNetworks [2] and Disney [3] among the early pioneers in this type of offering. In the mid 2000s an evolution of 3G technology begun to be implemented, namely High-Speed Downlink Packet Access (HSDPA). It is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family, also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) 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. Further speed increases are available with HSPA+, which provides speeds of up to 42 Mbit/s downlink and 84 Mbit/s with Release 9 of the 3GPP standards. 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 dollars 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. Earlier in the decade there were doubts about whether 3G might happen, and also whether 3G might become a commercial success. By the end of 2007 it had become clear that 3G was a reality and was clearly on the path to become a profitable venture. 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 internet. 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 3Gcapable 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 Computer had announced plans for embedded wireless internet on its iPad tablet devices beginning that Fall.
[edit] Fourth generation: All-IP networks
Main article: 4G
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.[21] 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, utilizing packet switching over internet, LAN or WAN networks via VoIP.[22]
The history of mobile phones begins with early efforts to develop mobile telephony concepts using two-way radios and continues through emergence of modern mobile phones and associated services. Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held mobile radio devices have been available since 1973. Mobile phone history is often divided into generations (first, second, third and so on) to mark significant step changes in capabilities as the technology improved over the years. In Europe, radio telephony was first used on the first-class passenger trains between Berlin and Hamburg in 1926. At the same time, radio telephony was introduced on passenger airplanes for air traffic security. Later radio telephony was introduced on a large scale in German tanks during the Second World War. In all of these cases the service was confined to specialists that were trained to use the equipment. In the early 1950s ships on the Rhine were among the first to use radio telephony with an untrained end customer as a user. However it was the 1940s onwards that saw the . Motorola developed a backpacked two-way radio, the Walkie-Talkie and a large hand-held two-way radio for the US military. This battery powered "Handie-Talkie" (HT) was about the size of a man's forearm. In 1946 in St. Louis, the Mobile Telephone Service was introduced In 1964 Improved Mobile Telephone Service was introduced with additional channels and more automatic handling of calls to the public switched telephone network. Even the addition of radio channels in three bands was insufficient to meet demand for vehicle-mounted mobile radio systems. In 1969, a patent for a wireless phone using an acoustic coupler for incoming calls was issued in US Patent Number 3,449,750 to George Sweigert of Euclid, Ohio on June 10, 1969, but did not include dialing a number for outgoing calls.
Emergence of commercial mobile phone services
Alongside the early developments outlined above, a different technology was also growing in popularity. Two-way mobile radios (known as mobile rigs) were used in vehicles such as taxicabs, police cruisers, and ambulances, but were not mobile phones, because they were not connected to the telephone network. The first fully automated mobile phone system for vehicles was launched in Sweden in 1960. Named MTA (Mobile Telephone system A), it allowed calls to be made and received in the car using a rotary dial. 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 (0G) cellular network, being slightly above previous proprietary and limited coverage networks.
Handheld cell phone
Dr. Martin Cooper of Motorola, made the first US analogue mobile phone call on a larger prototype model in 1973. This is a reenactment in 2007
On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first analogue mobile phone call using a heavy prototype model.
First generation: Cellular networks
The technological development that distinguished the First Generation mobile phones from the previous generation was the use of tramsfer calls. The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979. The initial launch network
covered the full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nation-wide 1G network.
Analog Motorola DynaTAC 8000X Advanced Mobile Phone System mobile phone as of 1983
Several other countries also launched 1G networks in the early 1980s including the UK, Mexico and Canada. A two year trial started in 1981 in Baltimore and Washington DC with 150 users and 300 Motorola DynaTAC pre-production phones. This took place on a seven tower cellular network that covered the area. The DC area trial turned into a commercial services in about 1983 with fixed cellular car phones also built by Motorola. They later added the 8000X to their Cellular offerings. A similar trial and commercial launch also took place in Chicago by Ameritech in 1983 using the famous first hand-held mobile phone Motorola DynaTAC. AT&T's 1971 proposal for Advanced Mobile Phone System (AMPS) was approved by the FCC in 1982 and frequencies were allocated in the 824±894 MHz band.[5] Analog AMPS was superseded by Digital AMPS in 1990. In 1984, Bell Labs developed modern commercial cellular technology (based, to a large extent, on the Gladden, Parelman Patent), which employed multiple, centrally controlled base stations (cell sites), each providing service to a small cell area. The sites were set up so that cells partially overlapped and different base stations operated using the same frequencies with little or no interference. Vodafone made the UK's first mobile call at a few minutes past midnight on 1 January 1985.[18] The technology in these early networks was pushed to the limit to accommodate increasing usage. The base stations and the mobile phones utilised variable transmission power, which allowed range and cell size to vary. As the system expanded and neared capacity, the ability to reduce transmission power allowed new cells to be added, resulting in more, smaller cells and
thus more capacity. The evidence of this growth can still be seen in the many older, tall cell site towers with no antennae on the upper parts of their towers. These sites originally created large cells, and so had their antennae mounted atop high towers; the towers were designed so that as the system expanded²and cell sizes shrank²the antennae could be lowered on their original masts to reduce range.
[edit] Second generation: Digital networks
Main articles: 2G, 2.5G, and 2.75G
Two 1991 GSM mobile phones with several AC adapters
In the 1990s, the 'second generation' (2G) mobile phone systems emerged, primarily using the GSM 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. Coinciding with the introduction of 2G systems was a trend away from the larger "brick" phones toward tiny 100±200g 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 whilst on the move.
Personal Handy-phone System mobiles and modems used in Japan around 1997 2003
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 3 December 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 amongst 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 trialled 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.
[edit] Third generation: High speed IP data networks and mobile broadband
Main article: 3G
As the use of 2G phones became more widespread and people began to utilize mobile phones in their daily lives, it became clear that demand for data services (such as access to the internet) was growing. Furthermore, 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.[19] 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 whilst retaining backwards compatibility:
y y y y
the 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. the ability for more than one mobile to share the same time slot. the introduction of QoS flags.
All these were put in place to allow for low latency, low bit rate communications such as VoIP.[20] 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 USA. 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 the Three/Hutchison group, on WCDMA. 2003 saw a further 8 commercial launches of 3G, six more on WCDMA and two more on the EV-DO standard. During the development of 3G systems, 2.5G systems such as CDMA2000 1x and GPRS were developed as extensions to existing 2G networks. These provide some of the features of 3G without fulfilling the promised high data rates or full range of multimedia services. CDMA20001X delivers theoretical maximum data speeds of up to 307 kbit/s. Just beyond these is the EDGE system which in theory covers the requirements for 3G system, but is so narrowly above these that any practical system would be sure to fall short. 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 [1], with companies such as RealNetworks [2] and Disney [3] among the early pioneers in this type of offering. In the mid 2000s an evolution of 3G technology begun to be implemented, namely High-Speed Downlink Packet Access (HSDPA). It is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family, also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) 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. Further speed increases are available with HSPA+, which provides speeds of up to 42 Mbit/s downlink and 84 Mbit/s with Release 9 of the 3GPP standards. 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 dollars 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. Earlier in the decade there were doubts about whether 3G might happen, and also whether 3G might become a commercial success. By the end of 2007 it had become clear that 3G was a reality and was clearly on the path to become a profitable venture. 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 internet. 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 3Gcapable 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 Computer had announced plans for embedded wireless internet on its iPad tablet devices beginning that Fall.
[edit] Fourth generation: All-IP networks
Main article: 4G
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.[21] 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, utilizing packet switching over internet, LAN or WAN networks via VoIP.[22]
