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Cellular Traffic
This article discusses the mobile cellular network aspect of teletraffic measurements. Mobile radio networks have traffic issues that do not arise in connection with the fixed line PSTN. Important aspects of cellular traffic include: quality of service targets, traffic capacity and cell size, spectral efficiency and sectorization, traffic capacity versus coverage, and channel holding time analysis. Teletraffic engineering in telecommunications network planning ensures that network costs are minimised without compromising the quality of service (QoS) delivered to the user of the network. This field of engineering is based on probability theory and can be used to analyse mobile radio networks, as well as other telecommunications networks. A mobile handset which is moving in a cell will record a signal strength that varies. Signal strength is subject to slow fading, fast fading and interference from other signals, resulting in degradation of the carrier-to-interference ratio (C/I). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Radio
Mobile radio or mobiles refer to wireless communications systems and devices which are based on radio frequencies(using commonly UHF or VHF frequencies), and where the path of communications is movable on either end. There are a variety of views about what constitutes mobile equipment. For US licensing purposes, mobiles may include hand-carried, (sometimes called ''portable''), equipment. An obsolete term is radiophone.Cited in many references including on escutcheons and silk-screened face plates on 1960s Motorola products including early HT-200 and Dispatcher-series mobiles. Later HT-200s dropped the term. A sales person or radio repair shop would understand the word ''mobile'' to mean vehicle-mounted: a transmitter-receiver (transceiver) used for radio communications from a vehicle. Mobile radios are mounted to a motor vehicle usually with the microphone and control panel in reach of the driver. In the US, such a device is typically powered by the host vehicle's 12 Volt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrier-to-interference Ratio
The signal-to-interference ratio (SIR or ''S/I''), also known as the carrier-to-interference ratio (CIR or ''C/I''), is the quotient between the average received modulated carrier power ''S'' or ''C'' and the average received co-channel interference power ''I'', i.e. crosstalk, from other transmitters than the useful signal. The CIR resembles the carrier-to-noise ratio (CNR or ''C/N''), which is the signal-to-noise ratio (SNR or ''S/N'') of a modulated signal before demodulation. A distinction is that interfering radio transmitters contributing to ''I'' may be controlled by radio resource management, while ''N'' involves noise power from other sources, typically additive white gaussian noise (AWGN). Carrier-to-noise-and-interference ratio (CNIR) The CIR ratio is studied in interference limited systems, i.e. where ''I'' dominates over ''N'', typically in cellular radio systems and broadcasting systems where frequency channels are reused in view to achieve high level of area c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Division Multiple Access
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies (see bandwidth). To permit this without undue interference between the users, CDMA employs spread spectrum technology and a special coding scheme (where each transmitter is assigned a code). CDMA optimizes the use of available bandwidth as it transmits over the entire frequency range and does not limit the user's frequency range. It is used as the access method in many mobile phone standards. IS-95, also called "cdmaOne", and its 3G evolution CDMA2000, are often simply referred to as "CDMA", but UMTS, the 3G standard used by GSM carriers, also uses "wideband CDMA", or W-CDMA, as well as TD-CDMA and TD-SCDMA, as its radio technologies. It can be also used as a channel or m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Repeater
A cellular repeater (also known as cell phone signal booster or cell phone signal amplifier) is a type of bi-directional amplifier used to improve cell phone reception. A cellular repeater system commonly consists of a donor antenna that receives and transmits signal from nearby cell towers, coaxial cables, a signal amplifier, and an indoor rebroadcast antenna. Common components Donor antenna A "donor antenna" is typically installed by a window or on the roof a building and used to communicate back to a nearby cell tower. A donor antenna can be any of several types, but is usually directional or omnidirectional. An omnidirectional antenna (which broadcast in all directions) is typically used for a repeater system that amplify coverage for all cellular carriers. A directional antenna is used when a particular tower or carrier needs to be isolated for improvement. The use of a highly directional antenna can help improve the donor's signal-to-noise ratio, thus improving the q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UMTS Frequency Bands
The UMTS frequency bands are radio frequencies used by third generation (3G) wireless Universal Mobile Telecommunications System networks. They were allocated by delegates to the World Administrative Radio Conference (WARC-92) held in Málaga-Torremolinos, Spain between 3 February 1992 and 3 March 1992. Resolution 212 (Rev.WRC-97), adopted at the World Radiocommunication Conference held in Geneva, Switzerland in 1997, endorsed the bands specifically for the International Mobile Telecommunications-2000 (IMT-2000) specification by referring to S5.388, which states "The bands 1,885-2,025 MHz and 2,110-2,200 MHz are intended for use, on a worldwide basis, by administrations wishing to implement International Mobile Telecommunications 2000 (IMT-2000). Such use does not preclude the use of these bands by other services to which they are allocated. The bands should be made available for IMT-2000 in accordance with Resolution 212 (Rev. WRC-97)." To accommodate the reality that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSM Frequency Bands
GSM frequency bands or frequency ranges are the cellular frequencies designated by the ITU for the operation of GSM mobile phones and other mobile devices. Frequency bands GSM frequency usage around the world A dual-band 900/1800 device is required to be compatible with most networks apart from deployments in ITU Region 2. GSM-900, EGSM/EGSM-900 and GSM-1800 GSM-900 and GSM-1800 are used in most parts of the world (ITU-Regions 1 and 3): Africa, Europe, Middle East, Asia (apart from Japan and South Korea where GSM has never been introduced) and Oceania. In common GSM-900 is most widely used. Fewer operators use GSM-1800. Mobile Communication Services on Aircraft (MCA) uses GSM-1800. In some countries GSM-1800 is also referred to as "Digital Cellular System" (DCS). GSM-850 and GSM-1900 GSM-1900 and GSM-850 are used in most of North, South and Central America (ITU-Region 2). In North America, GSM operates on the primary mobile communication bands 850 MHz and 1900 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Frequencies
Cellular frequencies are the sets of frequency ranges within the ultra high frequency band that have been assigned for cellular-compatible mobile devices, such as mobile phones, to connect to cellular networks.Guowang Miao, Jens Zander, Ki Won Sung, and Ben Slimane, Fundamentals of Mobile Data Networks, Cambridge University Press, , 2016. Most mobile networks worldwide use portions of the radio frequency spectrum, allocated to the mobile service, for the transmission and reception of their signals. The particular bands may also be shared with other radiocommunication services, e.g. broadcasting service, and fixed service operation. Overview Radio frequencies used for cellular networks differ in ITU Regions (Americas, Europe, Africa and Asia). The first commercial standard for mobile connection in the United States was AMPS, which was in the 800 MHz frequency band. In Nordic countries of Europe, the first widespread automatic mobile network was based on the NMT-450 standa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Congestion
Network congestion in data networking and queueing theory is the reduced quality of service that occurs when a network node or link is carrying more data than it can handle. Typical effects include queueing delay, packet loss or the blocking of new connections. A consequence of congestion is that an incremental increase in offered load leads either only to a small increase or even a decrease in network throughput. Network protocols that use aggressive retransmissions to compensate for packet loss due to congestion can increase congestion, even after the initial load has been reduced to a level that would not normally have induced network congestion. Such networks exhibit two stable states under the same level of load. The stable state with low throughput is known as congestive collapse. Networks use congestion control and congestion avoidance techniques to try to avoid collapse. These include: exponential backoff in protocols such as CSMA/CA in 802.11 and the similar CSMA/CD i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Site
A cell site, cell tower, or cellular base station is a cellular-enabled mobile device site where antennas and electronic communications equipment are placed (typically on a radio mast, tower, or other raised structure) to create a cell, or adjacent cells, in a cellular network. The raised structure typically supports antenna and one or more sets of transmitter/receivers transceivers, digital signal processors, control electronics, a GPS receiver for timing (for CDMA2000/IS-95 or GSM systems), primary and backup electrical power sources, and sheltering. Multiple cellular providers often save money by mounting their antennas on a common shared mast; since separate systems use different frequencies, antennas can be located close together without interfering with each other. Some provider companies operate multiple cellular networks and similarly use colocated base stations for two or more cellular networks, ( CDMA2000 or GSM, for example). Some cities require that cell sites b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell On Wheels
Mobile cell sites are infrastructures transportable on trucks, allowing fast and easy installation in restricted spaces. Their use is strategic for the rapid expansion of cellular networks putting into service point-to-point radio connections as well as supporting sudden increases in mobile traffic in the case of extraordinary events (trade fairs, sports events, concerts, emergencies, catastrophic events, etc.). Mobile cell sites are also used by law enforcement organizations to gather intelligence. Mobile cell sites require neither civil works nor foundations, just minimal requirements like commercial power and grounding. The mobile units have been designed to be a temporary solution, but if requested, they can be transformed into permanent stations. Different kinds of mobile cell sites There are several different kinds of mobile cell sites, every one of which has different usage characteristics. Rapid-deployment units (RDU) RDUs are mobile radio base stations transportable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Station Subsystem
The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of speech channels, allocation of radio channels to mobile phones, paging, transmission and reception over the air interface and many other tasks related to the radio network. Base transceiver station The base transceiver station, or BTS, contains the equipment for transmitting and receiving radio signals (transceivers), antennas, and equipment for encrypting and decrypting communications with the base station controller (BSC). Typically a BTS for anything other than a picocell will have several transceivers (TRXs) which allow it to serve several different frequencies and different sectors of the cell (in the case of sectorised base stations). A BTS is controlled by a parent BSC via the "base station control function" (BCF). The BCF is imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Resource Management
Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, wireless sensor systems, and radio broadcasting networks. RRM involves strategies and algorithms for controlling parameters such as transmit power, user allocation, beamforming, data rates, handover criteria, modulation scheme, error coding scheme, etc. The objective is to utilize the limited radio-frequency spectrum resources and radio network infrastructure as efficiently as possible. RRM concerns multi-user and multi-cell network capacity issues, rather than the point-to-point channel capacity. Traditional telecommunications research and education often dwell on channel coding and source coding with a single user in mind, but when several users and adjacent base stations share the same frequency channel it may not be possible to achie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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