A mobile phone can make and receive telephone calls to and from the public telephone network which includes other mobiles and fixed-line phones across the world. It does this by connecting to a cellular network provided by a mobile network operator.
In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these more general computing capabilities are referred to as smartphones.
The first hand-held mobile phone was demonstrated by Dr Martin Cooper of Motorola in 1973, using a handset weighing 2 kg. In 1983, the DynaTAC 8000x was the first to be commercially available. In the twenty years from 1990 to 2010, worldwide mobile phone subscriptions grew from 12.4 million to over 4.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.
HistoryRadiophones 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.
The first mobile telephone call made from a car occurred in St. Louis, Missouri, USA on June 17, 1946, using the Bell System's Mobile Telephone Service, but the system was impractical from what is considered a portable handset today. The equipment weighed 80 pounds (36 kg), and the AT&T service, basically a massive party line, cost US$30 per month (equal to $337.33 today) plus 30–40 cents per local call, equal to $3.37 to $4.5 today.
In 1956, the world’s first partly automatic car phone system, Mobile System A (MTA), was launched in Sweden. MTA phones were composed of vacuum tubes and relays, and had a weight of 40 kg. In 1962, a more modern version called Mobile System B (MTB) was launched, which was a push-button telephone, and which used transistors to enhance the telephone’s calling capacity and improve its operational reliability, thereby reducing the weight of the apparatus to 10 kg. In 1971, the MTD version was launched, opening for several different brands of equipment and gaining commercial success.
Martin Cooper, a Motorola researcher and executive is considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting, after a long race against Bell Labs for the first portable mobile phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a handheld mobile phone on April 3, 1973 to his rival, Dr. Joel S. Engel of Bell Labs.
The first commercially automated cellular network (the 1G) was launched in Japan by NTT in 1979, initially in the metropolitan area of Tokyo. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nationwide 1G network. In 1981, this was followed by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden. NMT was the first mobile phone network featuring international roaming. The first 1G network launched in the USA was Chicago-based Ameritech in 1983 using the Motorola DynaTAC mobile phone. Several countries then followed in the early-to-mid 1980s including the UK, Mexico and Canada.
The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja (now part of Elisa Group) in 1991 in Finland on the GSM standard, which also marked the introduction of competition in mobile telecoms when Radiolinja challenged incumbent Telecom Finland (now part of TeliaSonera) who ran a 1G NMT network.
In 2001, the first commercial launch of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard.
One of the newest 3G technologies to be implemented is 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.
The common components found on all phones are:
- A battery, typically rechargeable, providing the power source for the phone functions
- An input mechanism to allow the user to interact with the phone. The most common input mechanism is a keypad, but touch screens are also found in some high-end smartphones.
- Basic mobile phone services to allow users to make calls and send text messages.
- All GSM phones use a SIM card to allow an account to be swapped among devices. Some CDMA devices also have a similar card called a R-UIM.
- Individual GSM, WCDMA, iDEN and some satellite phone devices are uniquely identified by an International Mobile Equipment Identity (IMEI) number.
Several phone series have been introduced to address a given market segment, such as the RIM BlackBerry focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the Nokia Nseries of multimedia phones, the Palm Pre the HTC Dream and the Apple iPhone.
Other features that may be found on mobile phones include GPS navigation, music (MP3) and video (MP4) playback, RDS radio receiver, alarms, memo recording, personal digital assistant functions, ability to watch streaming video, video download, video calling, built-in cameras (1.0+ Mpx) and camcorders (video recording), with autofocus and flash, ringtones, games, PTT, memory card reader (SD), USB (2.0), dual line support, infrared, Bluetooth (2.0) and WiFi connectivity, instant messaging, Internet e-mail and browsing and serving as a wireless modem. Nokia and the University of Cambridge demonstrated a bendable cell phone called the Morph. Some phones can make mobile payments via direct mobile billing schemes or through contactless payments if the phone and point of sale support Near Field Communication (NFC). Some of the largest mobile phone manufacturers and network providers along with many retail merchants support, or plan to support, contactless payments through NFC-equipped mobile phones.
Some phones have an electromechanical transducer on the back which changes the electrical voice signal into mechanical vibrations. The vibrations flow through the cheek bones or forehead allowing the user to hear the conversation. This is useful in the noisy situations or if the user is hard of hearing. 
Software and applications
Other non-SMS data services used on mobile phones include mobile music, downloadable logos and pictures, gaming, gambling, adult entertainment and advertising. The first downloadable mobile content was sold to a mobile phone in Finland in 1998, when Radiolinja (now Elisa) introduced the downloadable ringtone service. In 1999, Japanese mobile operator NTT DoCoMo introduced its mobile Internet service, i-Mode, which today is the world's largest mobile Internet service.
The first mobile news service, delivered via SMS, was launched in Finland in 2000. Mobile news services are expanding with many organizations providing "on-demand" news services by SMS. Some also provide "instant" news pushed out by SMS.
Mobile payments were first trialled in Finland in 1998 when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments. Eventually, the idea spread and in 1999 the Philippines launched the first commercial mobile payments systems, on the mobile operators Globe and Smart. Today, mobile payments ranging from mobile banking to mobile credit cards to mobile commerce are very widely used in Asia and Africa, and in selected European markets.
Power supplyrechargeable batteries. There are a variety of ways used to charge cell phones, including USB, portable batteries, mains power (using an AC adapter), cigarette lighters (using an adapter), or a dynamo. In 2009, the first wireless charger was released for consumer use.
Development and adoption of a common charger solutionOn 17 February 2009, the GSM Association (GSMA), together with 17 mobile phone manufacturers and providers, announced their commitment to implementing a cross-industry standard for a universal charging solution for new mobile phones. The standard charger connector to be adopted by manufacturers in the Open Mobile Terminal Platform (OMTP) including Nokia, Motorola and Samsung is the micro-USB connector (several media reports erroneously reported this as the mini-USB). The new chargers will also be much more energy efficient than existing chargers. Having a standard charger for all phones means that manufacturers will no longer have to supply a charger with every new phone. The OMTP technical requirements describe a common charger with a standard USB-A receptacle and a detachable USB-A to microUSB-B cable.
In October 2009, the International Telecommunication Union (ITU) announced that it had also embraced the Universal Charging Solution standard – based on the OMTP specifications promoted by the GSMA – as its "energy-efficient one-charger-fits-all new mobile phone solution," and added: "Based on the Micro-USB interface, UCS chargers will also include a 4-star or higher efficiency rating — up to three times more energy-efficient than an unrated charger."
Common power supply standard in the European UnionIn 2009, many mobile phone manufacturers signed a Memorandum of Understanding (MoU), agreeing to make most new data-enabled cell phones marketed in the EU compatible with a common External Power Supply (EPS). All signatories agreed to develop a common specification for the charger "to allow for full compatibility and safety of chargers and mobile phones." The technical specifications for the common EPS were published in December 2010 as EN 62684:2010, “Interoperability specifications of common external power supply (EPS) for use with data-enabled mobile telephones." The mobile phone manufacturers who have agreed to this standard include the original signatories Apple, LG, Motorola, NEC, Nokia, Qualcomm, RIM, Samsung, Sony Ericsson, and Texas Instruments as well as Atmel, Emblaze Mobile, Huawei Technologies and TCT Mobile (Alcatel). The Memorandum of Understanding also provides for the use of the common External Power Supply with compliant phones not equipped with a MicroUSB receptacle: "4.2.1 ... if a manufacturer makes available an Adaptor from the Micro-USB connector of a Common EPS [External Power Supply] to a specific non-Micro-USB socket in the Mobile Phone, it shall constitute compliance to this article."
Common power supply standard in the People's Republic of ChinaIn 2006, the People's Republic of China issued a standard for mobile device power supplies (based on a 5V Power Supply with a USB-A receptacle and a detachable cable). The 2006 regulation is flexible regarding the interface on the mobile phone itself, allowing for the use of adapter cables if the mobile device is not equipped with a standard USB connector. The standard was revised in December, 2009 (CCSA YD/T 1591–2006 updated to YD/T 1591–2009).
Common power supply standard in South KoreaIn 2001, the South Korean Telecommunications Technology Association (TTA) released a "Standard on I/O Connection Interface of Digital Cellular Phone" TTAS.KO-06.0028. The main feature of the standard is the specification of a 24 pin connector / socket for mobile phones sold in Korea. The 24 pin connector handles power input (battery charging) and power output, as well as data communication (USB and other digital signals), analog audio inputs and outputs (for hands-free microphone, earphone) and other signals. The 2007 revision of the standard (TTAS.KO-06.0028/R4) specifies a smaller 20 pin connector to succeed the 24 pin connector.
A number of semiconductor companies offering flyback controllers, such as Power Integrations and CamSemi, now claim that the five-star standard can be achieved with use of their product.
Formerly, the most common form of mobile phone batteries were nickel metal-hydride, as they have a low size and weight. Lithium ion batteries are sometimes used, as they are lighter and do not have the voltage depression that nickel metal-hydride batteries do. Many mobile phone manufacturers have now switched to using lithium–polymer batteries as opposed to the older Lithium-Ion, the main advantages of this being even lower weight and the possibility to make the battery a shape other than strict cuboid. Mobile phone manufacturers have been experimenting with alternative power sources, including solar cells. A prototype mini solar panel from Wysips was able use perfectly as 'live phone' with Android phone. The mini solar panel can be installed on the Android phone screen, although the phone battery is still needed due to the solar panel solely has not been able to produce enough energy.
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A SIM card contains its unique serial number, internationally unique number of the mobile user (IMSI), security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to and two passwords (PIN for usual use and PUK for unlocking).
SIM cards are available in three standard sizes. The first is the size of a credit card (85.60 mm × 53.98 mm x 0.76 mm). The newer, most popular miniature version has the same thickness but a length of 25 mm and a width of 15 mm, and has one of its corners truncated (chamfered) to prevent misinsertion. The newest incarnation known as the 3FF or micro-SIM has dimensions of 15 mm × 12 mm. Most cards of the two smaller sizes are supplied as a full-sized card with the smaller card held in place by a few plastic links; it can easily be broken off to be used in a device that uses the smaller SIM.
The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrient for the Finnish wireless network operator Radiolinja. Giesecke & Devrient sold the first 300 SIM cards to Elisa (ex. Radiolinja).
Those cell phones that do not use a SIM Card have the data programmed in to their memory. This data is accessed by using a special digit sequence to access the "NAM" as in "Name" or number programming menu. From there, information can be added, including a new number for the phone, new Service Provider numbers, new emergency numbers, new Authentication Key or A-Key code, and a Preferred Roaming List or PRL. However, to prevent the phone being accidentally disabled or removed from the network, the Service Provider typically locks this data with a Master Subsidiary Lock (MSL). The MSL also locks the device to a particular carrier when it is sold as a loss leader.
The MSL applies only to the SIM, so once the contract has expired, the MSL still applies to the SIM. The phone, however, is also initially locked by the manufacturer into the Service Provider's MSL. This lock may be disabled so that the phone can use other Service Providers' SIM cards. Most phones purchased outside the U.S. are unlocked phones because there are numerous Service Providers that are close to one another or have overlapping coverage. The cost to unlock a phone varies but is usually very cheap and is sometimes provided by independent phone vendors.
A similar module called a Removable User Identity Module or RUIM card is present in some CDMA networks, notably in China and Indonesia.
Multi-card hybrid phones
A hybrid mobile phone can take more than one SIM card, even of different types. The SIM and RUIM cards can be mixed together, and some phones also support three or four SIMs
From 2010 onwards they became popular in India and Indonesia and other emerging markets, attributed to the desire to obtain the lowest on-net calling rate.
DisplayVirtually all mobile phones have an integrated display device, some with touchscreen function. The main measurements for screen size varies greatly by model.
Manufacturers use different methods to specify display size, usually width and height in pixels or the diagonal measured in inches.
In 2011, a 3G Android Smartphone was launched with dual 3.5 inch screens. Furthermore, the screens can be combined into a single 4.7 inch which turns it into a Tablet computer. It uses a single Snapdragon processor.
Central processing unitMobile phones have central processing units (CPUs), similar to those in computers, but optimised to operate in low power environments.
Mobile CPU performance depends not only on the clock rate (generally given in multiples of hertz)  but also the memory hierarchy also greatly affects overall performance. Because of these problems, the performance of mobile phone CPUs is often more appropriately given by scores derived from various standardized tests to measure the real effective performance in commonly used applications.
Mobile phones in society
China Mobile with over 500 million mobile phone subscribers. Over 50 mobile operators have over 10 million subscribers each, and over 150 mobile operators have at least one million subscribers by the end of 2009 (source wireless intelligence). In February 2010, there were 4.6 billion mobile phone subscribers, a number that is estimated to grow.
Competitive forces emerged in the Asia Pacific (excluding Japan) region at Q3 2010 to the detriment of market leader Nokia. Brands such as Micromax, Nexian, and i-Mobile chipped away at Nokia's market share plus Android powered smartphones also gained momentum across the region at the cost of Nokia.
Based on IDC India, Nokia's market share dropped significantly to 36 percent in the second quarter, from 56.8 percent in the same quarter last year and further drop to 31.5 percent in the third quarter, reflecting the growing share of Chinese and Indian vendors of low-end mobile phones.
Based on IDC in the last quarter of 2010, RIM has been knocked out from the top five list global mobile phone sellers. The number one rank is still Nokia followed by Samsung, LG Electronics, ZTE and Apple. For the first time Chinese ZTE is among the top five list and mainly make of lower cost phones.
For the year of 2010, Sony Ericsson and Motorola are out from the top of five list and have been replaced by LG Electronics and Apple. Significant increase from 16.5 percent to 30.6 percent has been done by many small not yet recognized brands (some of them are new brands) – Others-2. Total sales in 2010 to end users were 1.6 billion units or increase by 31.8 percent from the year of 2009.
At April 6, 2011 market capitalization of HTC surpassed Nokia with $33.8 billion over $33.4 billion respectively. The credit agency was also downgraded Nokia's debt from A2 to A3.
Top Five Mobile Phone Market Share
- Source: IDC Worlwide Mobile Phone Trackers, April 28, 2011
- Note: Vendor shipments are branded shipments and exclude OEM sales for all vendors
June 2011: In 3 years, RIM has lossed about 82 percent of the capitalization. As a barometer in North America RIM's market share dropped significantly from 54 percent to 13 percent in the last 2 years.
Other manufacturers include Audiovox (now UTStarcom), CECT, HTC Corporation, Fujitsu, Kyocera, Mitsubishi Electric, NEC, Panasonic, Palm, Pantech Wireless Inc., Philips, Qualcomm Inc., Research In Motion Ltd. (RIM), Sagem, Sanyo, Sharp, Sierra Wireless, Just5, SK Teletech, T&A Alcatel, Huawei, Trium, Toshiba and Vidalco. There are also specialist communication systems related to (but distinct from) mobile phones.
MediaIn 1998, one of the first examples of selling media content through the mobile phone was the sale of ringtones by Radiolinja in Finland. Soon afterwards, other media content appeared such as news, videogames, jokes, horoscopes, TV content and advertising. Most early content for mobile tended to be copies of legacy media, such as the banner advertisement or the TV news highlight video clip. Recently, unique content for mobile has been emerging, from the ringing tones and ringback tones in music to "mobisodes," video content that has been produced exclusively for mobile phones.
In 2006, the total value of mobile-phone-paid media content exceeded Internet-paid media content and was worth 31 billion dollars (source Informa 2007). The value of music on phones was worth 9.3 billion dollars in 2007 and gaming was worth over 5 billion dollars in 2007.
The advent of media on the mobile phone has also produced the opportunity to identify and track Alpha Users or Hubs, the most influential members of any social community. AMF Ventures measured in 2007 the relative accuracy of three mass media, and found that audience measures on mobile were nine times more accurate than on the Internet and 90 times more accurate than on TV.[original research?]
The mobile phone is often called the Fourth Screen (if counting cinema, TV and PC screens as the first three) or Third Screen (counting only TV and PC screens).[weasel words] It is also called the Seventh of the Mass Media (with Print, Recordings, Cinema, Radio, TV and Internet the first six).
PrivacyThe movements of a mobile phone user can be tracked by their service provider and, if desired, by law enforcement agencies and their government. Both the SIM card and the handset can be tracked. China has proposed using this technology to track commuting patterns of Beijing city residents.
ExamplesMobile phones are used for a variety of purposes, including keeping in touch with family members, conducting business, and having access to a telephone in the event of an emergency. Some people carry more than one cell phone for different purposes, such as for business and personal use. Multiple SIM cards may also be used to take advantage of the benefits of different calling plans—a particular plan might provide cheaper local calls, long-distance calls, international calls, or roaming. A study by Motorola found that one in ten cell phone subscribers have a second phone that often is kept secret from other family members. These phones may be used to engage in activities including extramarital affairs or clandestine business dealings. The mobile phone has also been used in a variety of diverse contexts in society, for example:
- Organizations that aid victims of domestic violence may offer a cell phone to potential victims without the abuser's knowledge. These devices are often old phones that are donated and refurbished to meet the victim's emergency needs.
- The advent of widespread text messaging has resulted in the cell phone novel; the first literary genre to emerge from the cellular age via text messaging to a website that collects the novels as a whole. Paul Levinson, in Information on the Move (2004), says "...nowadays, a writer can write just about as easily, anywhere, as a reader can read" and they are "not only personal but portable."
- Mobile telephony also facilitates activism and public journalism being explored by Reuters and Yahoo! and small independent news companies such as Jasmine News in Sri Lanka.
- Mobile phones help lift poor out of poverty. The United Nations has reported that mobile phones—spreading faster than any other information technology—can improve the livelihood of the poorest people in developing countries. The economic benefits of mobile phones go well beyond access to information where a landline or Internet is not yet available in rural areas, mostly in Least Developed Countries. Mobile phones have spawned a wealth of micro-enterprises, offering work to people with little education and few resources, such as selling airtime on the streets and repairing or refurbishing handsets.
- In Mali and some African countries, villagers sometimes had to go from village to village all day, covering up to 20 villages, to let friends and relatives know about a wedding, a birth or a death, but such travel is no longer necessary if the villages are within the coverage area of a mobile phone network. Like in many African countries, the coverage is better than that of landline networks, and most people own a mobile phone. However, small villages have no electricity, leaving mobile phone owners to have to recharge their phone batteries using a solar panel or motorcycle battery.
- The TV industry has recently started using mobile phones to drive live TV viewing through mobile apps, advertising, social tv, and mobile TV. 86% of Americans use their mobile phone while watching TV.
- In March 2011, a pilot project experimenting with branchless banking was launched by the International Finance Corporation, a member of the World Bank, and Bank Harapan Bali, a subsidiary of Bank Mandiri—the biggest bank in Indonesia and one of the cellular operators in Bali. Its aim is to increase the amount of bank customers. In Indonesia, only 60 million people have a bank account even though banks have existed for more than a hundred years, whereas 114 million people have become users of mobile phones in only two decades. Branchless banking has been successful in Kenya, South Africa and Philippines.
SharingIn some parts of the world, mobile phone sharing is common. It is prevalent in urban India, as families and groups of friends often share one or more mobiles among their members. There are obvious economic benefits, but often familial customs and traditional gender roles play a part. For example, in Burkina Faso, it is not uncommon for a village to have access to only one mobile phone. The phone is typically owned by a person who is not natively from the village, such as a teacher or missionary, but it is expected that other members of the village are allowed to use the cell phone to make necessary calls.
Due to the increasing complexity of mobile phones, they are often more like mobile computers in their available uses. This has introduced additional difficulties for law enforcement officials in distinguishing one usage from another as drivers use their devices. This is more apparent in those countries which ban both handheld and hands-free usage, rather those who have banned handheld use only, as officials cannot easily tell which function of the mobile phone is being used simply by visually looking at the driver. This can lead to drivers being stopped for using their device illegally on a phone call when, in fact, they were using the device for a legal purpose such as the phone's incorporated controls for car stereo or satnav.
A recently published study has reviewed the incidence of mobile phone use while cycling and its effects on behaviour and safety.
In schoolsSome schools limit or restrict the use of mobile phones. Schools set restrictions on the use of mobile phones because of the use of cell phones for cheating on tests, harassment and bullying, causing threats to the schools security, distractions to the students, and facilitating gossip and other social activity in school. Many mobile phones are banned in school locker room facilities, public restrooms and swimming pools due to the built-in cameras that most phones now feature.
PrivacyMobile phones have numerous privacy issues.
Governments, law enforcement and intelligence services use mobiles to perform surveillance in the UK and the US They possess technology to activate the microphones in cell phones remotely in order to listen to conversations that take place near to the person who holds the phone.
Mobile phones are also commonly used to collect location data. While the phone is turned on, the geographical location of a mobile phone can be determined easily (whether it is being used or not), using a technique known multilateration to calculate the differences in time for a signal to travel from the cell phone to each of several cell towers near the owner of the phone.
Health effectsOn 31st May 2011, the World Health Organization confirmed that mobile phone use represents a long-term health risk, classifying mobile phone radiation as a "carcinogenic hazard" and "possibly carcinogenic to humans" after a team of scientists reviewed peer-review studies on cell phone safety. One study of past cell phone use cited in the report showed a "40% increased risk for gliomas (brain cancer) in the highest category of heavy users (reported average: 30 minutes per day over a 10‐year period)." This is a reversal from their prior position that cancer was unlikely to be caused by cellular phones or their base stations and that reviews had found no convincing evidence for other health effects. Certain countries, including France, have warned against the use of cell phones especially by minors due to health risk uncertainties.
The effect mobile phone radiation has on human health is the subject of recent interest and study, as a result of the enormous increase in mobile phone usage throughout the world (as of June 2009, there were more than 4.3 billion users worldwide). Mobile phones use electromagnetic radiation in the microwave range, which some believe may be harmful to human health. A large body of research exists, both epidemiological and experimental, in non-human animals and in humans, of which the majority shows no definite causative relationship between exposure to mobile phones and harmful biological effects in humans. This is often paraphrased simply as the balance of evidence showing no harm to humans from mobile phones, although a significant number of individual studies do suggest such a relationship, or are inconclusive. Other digital wireless systems, such as data communication networks, produce similar radiation.
At least some recent studies have found an association between cell phone use and certain kinds of brain and salivary gland tumors. Lennart Hardell and other authors of a 2009 meta-analysis of 11 studies from peer-reviewed journals concluded that cell phone usage for at least ten years “approximately doubles the risk of being diagnosed with a brain tumor on the same ("ipsilateral") side of the head as that preferred for cell phone use.”
In addition, a mobile phone can spread infectious diseases by its frequent contact with hands. One study came to the result that pathogenic bacteria are present on approximately 40% of mobile phones belonging to patients in a hospital, and on approximately 20% of mobile phones belonging to hospital staff.
Future evolution: Broadband Fourth generation (4G)The recently released 4th generation, also known as Beyond 3G, aims to provide broadband wireless access with nominal data rates of 100 Mbit/s to fast moving devices, and 1 Gbit/s to stationary devices defined by the ITU-R 4G systems may be based on the 3GPP LTE (Long Term Evolution) cellular standard, offering peak bit rates of 326.4 Mbit/s. It may perhaps also be based on WiMax or Flash-OFDM wireless metropolitan area network technologies that promise broadband wireless access with speeds that reaches 233 Mbit/s for mobile users. The radio interface in these systems is based on all-IP packet switching, MIMO diversity, multi-carrier modulation schemes, Dynamic Channel Assignment (DCA) and channel-dependent scheduling. A 4G system should be a complete replacement for current network infrastructure and is expected to be able to provide a comprehensive and secure IP solution where voice, data, and streamed multimedia can be given to users on a "Anytime, Anywhere" basis, and at much higher data rates than previous generations. Sprint in the US has claimed its WiMax network to be "4G network" which most cellular telecoms standardization experts dispute repeatedly around the world. Sprint's 4G is seen as a marketing gimmick as WiMax itself is part of the 3G air interface. The officially accepted, ITU ratified standards-based 4G networks are not expected to be commercially launched until 2011. In March 2011, KT from South Korea announced that they has expanded its high-speed wireless broadband network by 4G WiBro cover 85 percent of the population. It is the largest broadband network covered in the world, followed by Japan and US with 70 percent and 36 percent respectively. At the beginning of 2011, some major mobile phone companies have released their 4G mobile phones such as from Motorola, HTC and Samsung.
Comparison to similar systems
- Car phone
- A type of telephone permanently mounted in a vehicle, these often have more powerful transmitters, an external antenna and loudspeaker for hands free use. They usually connect to the same networks as regular mobile phones.
- Cordless telephone (portable phone)
- Cordless phones are telephones which use one or more radio handsets in place of a wired handset. The handsets connect wirelessly to a base station, which in turn connects to a conventional land-line for calling. Unlike mobile phones, cordless phones use private base stations (belonging to the land-line subscriber), which are not shared.
- Professional Mobile Radio
- Advanced professional mobile radio systems can be very similar to mobile phone systems. Notably, the IDEN standard has been used as both a private trunked radio system as well as the technology for several large public providers. Similar attempts have even been made to use TETRA, the European digital PMR standard, to implement public mobile networks.
- Radio phone
- This is a term which covers radios which could connect into the telephone network. These phones may not be mobile; for example, they may require a mains power supply, or they may require the assistance of a human operator to set up a PSTN phone call.
- Satellite phone
- This type of phone communicates directly with an artificial satellite, which in turn relays calls to a base station or another satellite phone. A single satellite can provide coverage to a much greater area than terrestrial base stations. Since satellite phones are costly, their use is typically limited to people in remote areas where no mobile phone coverage exists, such as mountain climbers, mariners in the open sea, and news reporters at disaster sites.
- IP Phone
- This type of phone delivers or receives calls over internet, LAN or WAN networks using VoIP as opposed to traditional CDMA and GSM networks. In business, the majority of these IP Phones tend to be connected via wired Ethernet, however wireless varieties do exist. Several vendors have developed standalone WiFi phones. Additionally, some cellular mobile phones include the ability to place VoIP calls over cellular high speed data networks and/or wireless internet.