Cellular network
These base stations provide the cell with the network coverage which can be used for transmission of voice, data, and other types of content via radio waves.The design of cellular networks allows for seamless handover, enabling uninterrupted communication when a device moves from one cell to another.In addition to traditional voice and data services, cellular networks now support Internet of Things (IoT) applications, connecting devices such as smart meters, vehicles, and industrial sensors.The evolution of cellular networks from 1G to 5G has progressively introduced faster speeds, lower latency, and support for a larger number of devices, enabling advanced applications in fields such as healthcare, transportation, and smart cities.Private cellular networks can be used for research[3] or for large organizations and fleets, such as dispatch for local public safety agencies or a taxicab company, as well as for local wireless communications in enterprise and industrial settings such as factories, warehouses, mines, power plants, substations, oil and gas facilities and ports.The increased capacity in a cellular network, compared with a network with a single transmitter, comes from the mobile communication switching system developed by Amos Joel of Bell Labs[5] that permitted multiple callers in a given area to use the same frequency by switching calls to the nearest available cellular tower having that frequency available.Consider the case of a taxi company, where each radio has a manually operated channel selector knob to tune to different frequencies.The development of radio transmissions by inventor and engineer Guglielmo Marconi in 1895 set the stage for the future of broadcast communication, which would later form the basis of the cellular network.This proposal was put forward by Douglas H. Ring, a Bell Labs engineer, in an internal memo suggesting the development of a cellular telephone system by AT&T.[7][8] The first commercial cellular network, the 1G generation, was launched in Japan by Nippon Telegraph and Telephone (NTT) in 1979, initially in the metropolitan area of Tokyo.[15][16] In December 1981, Sweden awarded Comvik with a license to operate its own automatic cellular network in the spirit of market competition.TDMA is a familiar technology for telephone companies, which used time-division multiplexing to add channels to their point-to-point wireline plants before packet switching rendered FDM obsolete.Although more sophisticated than older multiple access schemes (and unfamiliar to legacy telephone companies because it was not developed by Bell Labs), CDMA has scaled well to become the basis for 3G cellular radio systems.In the United States, the Federal Communications Commission (FCC) limits omnidirectional cell tower signals to 100 watts of power.If the tower has directional antennas, the FCC allows the cell operator to emit up to 500 watts of effective radiated power (ERP).This provides a minimum of three channels, and three towers for each cell and greatly increases the chances of receiving a usable signal from at least one direction.[39] Cell phone companies also use this directional signal to improve reception along highways and inside buildings like stadiums and arenas.If communication was interrupted due to a loss of a signal, the taxi driver asked the base station operator to repeat the message on a different frequency.A mobile phone is a portable telephone which receives or makes calls through a cell site (base station) or transmitting tower.In rural areas with low-band coverage and tall towers, basic voice and messaging service may reach 50 miles (80 km), with limitations on bandwidth and number of simultaneous calls.There are many functions that are performed by this network in order to make sure customers get the desired service including mobility management, registration, call set-up, and handover.This is known as "soft handoff" because, unlike with traditional cellular technology, there is no one defined point where the phone switches to the new cell.In IS-95 inter-frequency handovers and older analog systems such as NMT it will typically be impossible to test the target channel directly while communicating.The following table shows the dependency of the coverage area of one cell on the frequency of a CDMA2000 network:[41] Lists and technical information: Starting with EVDO the following techniques can also be used to improve performance: Equipment: Other:
Mobile network operatorAntennasCommon typesDipoleFractalMonopoleSatellite dishTelevisionBlock upconverterCoaxial cableCounterpoise (ground system)Feed lineLow-noise block downconverterPassive radiatorReceiverRotatorTransmitterTwin-leadAntenna farmAmateur radioHotspotMunicipal wireless networkRadio masts and towersWirelessWireless device radiation and healthWireless electronic devices and healthInternational Telecommunication UnionRadio RegulationsWorld Radiocommunication ConferenceBoresightFocal cloudGround planeMain lobeNear and far fieldSide lobeVertical planeArray gainDirectivityEfficiencyElectrical lengthEquivalent radiusFactorFriis transmission equationHeightRadiation patternRadiation resistanceRadio propagationRadio spectrumSignal-to-noise ratioSpurious emissionBeam steeringBeam tiltBeamformingSmall cellBell Laboratories LayeredSpace-Time (BLAST)Multiple-input multiple-output (MIMO)ReconfigurationSpread spectrumWideband Space DivisionMultiple Access (WSDMA)telecommunications networktransceiverbase stationradio wavesdevicesmobile phonestabletslaptopsmobile broadband modemswearable devicessmartwatcheshandoverMultiple Input Multiple Outputpublic switched telephone networkInternet accessInternet of Thingssmart meterssmart citiescellular radioradio base stationsco-channel interferencecapacityAmos Joelinterferencefrequency-division multiple accessfrequencytime-division multiple accessHistory of mobile phonesradio transmissionsGuglielmo MarconiDouglas H. RingBell LabsNippon Telegraph and TelephoneNordic Mobile TelephoneTeleverketSwedish Post and Telecom AuthorityBell SystemChicagoDallasbreakup of the Bell SystemRegional Bell Operating CompaniesMillicom Inc.wireless revolutiondigital networkspower MOSFETRF amplifierRF CMOSRF circuitchannel access methodsD-AMPScode-division multiple accessfull-duplexfrequency-division multiplexingtime-division multiplexingdigitalstore and forwardlatencypacket switchingWorld War IICold Wardirect-sequence spread spectrumantenna diversityspatial multiplexingQuadrature Amplitude Modulationbandwidthorthogonal frequency-division multiple accessinter-cell interference coordination