Broadcast messages and paging

Practically every cellular system has some kind of broadcast mechanism. This can be used directly for distributing information to multiple mobiles, commonly, for example in mobile telephony systems, the most important use of broadcast information is to set up channels for one to one communication between the mobile transreceiver and the base station. This is called paging.

The details of the process of paging vary somewhat from network to network, but normally we know a limited number of cells where the phone is located (this group of cells is called a Location Area in the GSM or UMTS system, or Routing Area if a data packet session is involved). Paging takes place by sending the broadcast message to all of those cells. Paging messages can be used for information transfer. This happens in pagers, in CDMA systems for sending SMS messages, and in the UMTS system where it allows for low downlink latency in packet-based connections.

Cellular network

A cellular network is a radio network made up of a number of radio cells (or just cells) each served by at least one fixed-location transceiver known as a cell site or base station. These cells cover different land areas to provide radio coverage over a wider area than the area of one cell, so that a variable number of portable transceivers can be used in any one cell and moved through more than one cell during transmission.

Cellular networks offer a number of advantages over alternative solutions:

• increased capacity
• reduced power usage
• larger coverage area
• reduced interference from other signals

An example of a simple non-telephone cellular system is an old taxi driver's radio system where the taxi company has several transmitters based around a city that can communicate directly with each taxi.

Mobile phone

A mobile phone or mobile (also called cellphone and handphone,^[1] as well as cell phone, wireless phone, cellular phone, cell, cellular telephone, mobile telephone or cell telephone) is a long-range, electronic device used for mobile telecommunications (mobile telephony, text messaging or data transmition) over a cellular network of specialized base stations known as cell sites. In addition to the standard voice function, current mobile phones may support many additional services, and accessories, such as SMS for text messaging, email, packet switching for access to the Internet, gaming, Bluetooth, infrared, camera with video recorder and MMS for sending and receiving photos and video, MP3 player, radio and GPS. Most current mobile phones connect to a cellular network consisting of switching points and base stations (cell sites) owned by a mobile network operator (the exception is satellite phones, which are mobile but not cellular).

As opposed to a radio telephone, a mobile phone offers full duplex communication, automatised calling to and paging from a public switched telephone network (PSTN), handoff (am. English) or handover (European term) during a phone call when the user moves from one cell (base station coverage area) to another. A mobile phone offers wide area service, and should not be confused with a cordless telephone, which also is a wireless phone, but only offer telephony service within a limited range, e.g. within a home or an office, through a fixed line and a base station owned by the subscriber.

The International Telecommunication Union estimated that mobile cellular subscriptions worldwide would reach approximately 4.1 billion by the end of 2008.^[2] Mobile phones have gained increased importance in the sector of Information and communication technologies for development in the 2000s and have effectively started to reach the bottom of the economic pyramid.^[3]

Third generation

Not long after the introduction of 2G networks, projects began to develop third generation (3G) systems. Inevitably there were many different standards with different contenders pushing their own technologies. Quite differently from 2G systems, however, the meaning of 3G has been standardized in the IMT-2000 standardization processing. This process did not standardize on a technology, but rather on a set of requirements (2 Mbit/s maximum data rate indoors, 384 kbit/s outdoors, for example). At that point, the vision of a single unified worldwide standard broke down and several different standards have been introduced.

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). In March the first 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. CDMA2000-1X 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.

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 are 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.

Live streaming of radio and television [2] to 3G handsets is one future direction for the industry, with companies such as RealNetworks [3] and Disney [4] recently announcing services.

Second generation

In the 1990s, 'second generation' (2G) mobile phone systems such as GSM, IS-136 ("TDMA"), iDEN and IS-95 ("CDMA") began to be introduced. In 1991 the first GSM network (Radiolinja) opened in Finland. 2G phone systems were characterized by digital circuit switched transmission and the introduction of advanced and fast phone-to-network signaling. 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 "brickle" phones toward tiny 100–200g hand-held devices, which soon became the norm. This change was possible through technological improvements such as more advanced batteries and more energy-efficient electronics, but also was largely related to the higher density of cellular sites caused by increasing usage levels. This decreased the demand for high transmission powers to reach distant towers for customers to be satisfied.

The second generation introduced a new variant to communication, as SMS text messaging became possible, initially on GSM networks and eventually on all digital networks. The first machine-generated SMS message was sent in the UK in 1991. The first person-to-person SMS text message was sent in Finland in 1993. Soon SMS became the communication method of preference for the youth. Today in many advanced markets the general public prefers sending text messages to placing voice calls.

2G also introduced the ability to access media content on mobile phones, when Radiolinja (now Elisa) in Finland introduced the downloadable ring tone as paid content. Finland was also the first country where advertising appeared on the mobile phone when a free daily news headline service on SMS text messaging was launched in 2000, sponsored by advertising

First generation

On April 3, 1973, Motorola employee Dr. Martin Cooper placed a call to Dr. Joel S. Engel, head of research at AT&T's Bell Labs, while walking the streets of New York City talking on the first Motorola DynaTAC prototype in front of reporters. Motorola has a long history of making automotive radio, especially two-way radios for taxicabs and police cruisers.

In 1978, Bell Labs launched a trial of the first commercial cellular network in Chicago using AMPS [1], but this network was not approved by the FCC until 1982.

The first commercial launch of cellular telecoms was launched by NET in Tokyo Japan in 1979. In 1981 the NMT system was launched in Denmark, Finland, Norway and Sweden.

The first handheld mobile phone in the US market was the Motorola Dyna 8000X, which received approval in 1983.

Mobile phones began to proliferate through the 1980s with the introduction of "cellular" phones based on cellular networks with multiple base stations located relatively close to each other, and protocols for the automated "handover" between two cells when a phone moved from one cell to the other. At this time analog transmission was in use in all systems. Mobile phones were somewhat larger than current ones, and at first, all were designed for permanent installation in vehicles (hence the term car phone). Soon, some of these bulky units were converted for use as "transportable" phones the size of a briefcase. Motorola introduced the first truly portable, hand held phone. These systems (NMT, AMPS, TACS, RTMI, C-Net, and Radiocom 2000) later became known as first generation (1G) mobile phones

Early years

In 1910 Lars Magnus Ericsson applied the idea of mobile phone by installing a telephone in his car. Using a pair of long electric wires he could connect to national telephone network travelling across the country. In 1946 soviet engineers G. Shapiro and I. Zaharchenko succesfully tested their version of mobile phone mounted inside a car. The device could connect to local telephone network on a range up to 20 kilometers. In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs engineers, proposed hexagonal cells for mobile phones.^[1] Philip T. Porter, also of Bell Labs, proposed that the cell towers be at the corners of the hexagons rather than the centers and have directional antennas that would transmit/receive in 3 directions (see picture at right) into 3 adjacent hexagon cells.^{[2] [3]} The technology did not exist then and the frequencies had not yet been allocated. Cellular technology was undeveloped until the 1960s, when Richard H. Frenkiel and Joel S. Engel of Bell Labs developed the electronics.

Recognizable mobile phones with direct dialing have existed at least since the 1950s. In the 1954 movie Sabrina, the businessman Linus Larrabee (played by Humphrey Bogart) makes a call from the phone in the back of his limousine.

The first fully automatic mobile phone system, called MTA (Mobile Telephone system A), was developed by Ericsson and commercially released in Sweden in 1956. This was the first system that did require any kind of manual control, but had the disadvantage of a phone weight of 40 kg (90 lb). MTB, an upgraded version with transistors, weighing 9 kg (20 lb), was introduced in 1965 and used DTMF signaling. It had 150 customers in the beginning and 600 when it shut down in 1983.

In 1957 young soviet radio engineer Leonid Kupriyanovich from Moscow created the portable mobile phone, named after himself as LK-1 or "radiophone".^[4] This true mobile phone consisted of a relatively small-sized handset equipped with an antenna and rotary dial, and communicated with a base station. Kupriyanovich's "radiophone" had 3 kilogram of total weight, could operate up to 20 or 30 kilometers, and had 20 or 30 hours of battery lifespan. LK-1 and its layout was depicted in popular soviet magazines as "Nauka i zhizn", 8, 1957, p. 49, "Yuniy technik", 7, 1957, p. 43-44. Engineer Kupriyanovich patented his mobile phone in the same year 1957 (author's certificate (USSR Patent) # 115494, 1.11.1957). The base station of LK-1 ( called ATR, or Automated Telephone Radiostation) could connect to local telephone network and serve several customers.

In 1958, Kupriyanovich resized his "radiophone" to "pocket" version. The weight of improved "light" handset was about 500 gram.

In 1958 the USSR also began to deploy the "Altay" national civil mobile phone service specially for motorists. The newly-developed mobile telephone system was based on Soviet MRT-1327 standard. The main developers of the Altay system were Voronezh Science Research Institute of Communications (VNIIS)and the State Specialized Project Institute (GSPI). In 1963 this service started in Moscow, and in 1970 the Altay service already was deployed in 30 cities of the USSR. The last upgraded versions of the Altay system are still in use in some places of Russia as a trunking system.

In 1966, Bulgaria presented the pocket mobile automatic phone RAT-0,5 combined with a base station RATZ-10 (RATC-10) on Interorgtechnika-66 international exhibition. One base station, connected to one telephone wire line, could serve up to 6 customers.

In 1967, each mobile phone had to stay within the cell area serviced by one base station throughout the phone call. This did not provide continuity of automatic telephone service to mobile phones moving through several cell areas. In 1970 Amos E. Joel, Jr., another Bell Labs engineer,^[5] invented an automatic "call handoff" system to allow mobile phones to move through several cell areas during a single conversation without loss of conversation.

In December 1971, AT&T submitted a proposal for cellular service to the Federal Communications Commission (FCC). After years of hearings, the FCC approved the proposal in 1982 for Advanced Mobile Phone Service (AMPS) and allocated frequencies in the 824-894 MHz band.^[6] Analog AMPS was superseded by Digital AMPS in 1990.

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.