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Mobility Management
Mobility management is one of the major functions of a GSM or a UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, allowing calls, SMS and other mobile phone services to be delivered to them. Location update procedure A GSM or UMTS network, like all cellular networks, is basically a radio network of individual cells, known as base stations. Each base station covers a small geographical area which is part of a uniquely identified location area. By integrating the coverage of each of these base stations, a cellular network provides a radio coverage over a much wider area. For GSM, a base station is called a base transceiver station (BTS), and for UMTS it is called a Node B. A group of base stations is named a location area, or a routing area. The location update procedure allows a mobile device to inform the cellular network whenever it moves from one location area to the next. Mobiles are responsible for detecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcasting
Broadcasting is the distribution (business), distribution of sound, audio or video content to a dispersed audience via any electronic medium (communication), mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a :wikt:one-to-many, one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and radio receiver, receivers. Before this, all forms of electronic communication (early radio, telephone, and telegraph) were wikt:one-to-one, one-to-one, with the message intended for a single recipient. The term ''broadcasting'' evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Service Providers
An Internet service provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non-profit, or otherwise privately owned. Internet services typically provided by ISPs can include Internet access, Transit (Internet), Internet transit, domain name registration, Web hosting service, web hosting, Usenet service, and colocation centre, colocation. An ISP typically serves as the access point or the Default gateway, gateway that provides a user access to everything available on the Internet. Such a network can also be called as an eyeball network. History The Internet (originally ARPAnet) was developed as a network between government research laboratories and participating departments of universities. Other companies and organizations joined by direct connection to the Internet backbone, backbone, or by arrangements through other connected companies, so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information. IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974, which was complemented by a connection-oriented service that became the basis for the Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as ''TCP/IP''. The first major version of IP, Internet Protocol Version 4 (IPv4), is the do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPRS
General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM). GPRS was established by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP). GPRS is typically sold according to the total volume of data transferred during the billing cycle, in contrast with circuit switched data, which is usually billed per minute of connection time, or sometimes by one-third minute increments. Usage above the GPRS bundled data cap may be charged per MB of data, speed limited, or disallowed. GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service (QoS) is guaranteed durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (signal Processing)
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ''baseband bandwidth''. Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. Baseband bandwidth applies to a low-pass filter or baseband signal; the bandwidth is equal to its upper cutoff frequency. Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy and is one of the determinants of the capacity of a given communication channel. A key characteristic of bandwidth is that any band of a given width can carry the same amount of information, regardless of where that band is located in the frequency spectrum. For example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Global Identity
Cell Global Identity (CGI) is a globally unique identifier for a Base Transceiver Station in mobile phone networks. It consists of four parts: Mobile Country Code (MCC), Mobile Network Code (MNC), Location Area Code (LAC) and Cell Identification (CI). It is an integral part of 3GPP specifications for mobile networks, for example, for identifying individual base stations to "handover" ongoing phone calls between separately controlled base stations, or between different mobile technologies. MCC and MNC make up a PLMN identifier, and PLMN and LAC make up a location area identity (LAI), which uniquely identifies a Location Area of a given operator's network. So a CGI can be seen as a LAI with added Cell Identification, to further identify the individual base station of that Location Area. Overview * a CGI (e.g. 001-02-3-4) consists of: ** a LAI (001-02-3), which consists of: *** a PLMN (001-02), which consists of: **** MCC (001) **** MNC (02) *** and a LAC (03), ** and a CI (4) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Network Controller
The Radio Network Controller (RNC) is a governing element in the UMTS radio access network (UTRAN) and is responsible for controlling the Node Bs that are connected to it. The RNC carries out radio resource management, some of the mobility management functions and is the point where encryption is done before user data is sent to and from the mobile. The RNC connects to the Circuit Switched Core Network through Media Gateway ( MGW) and to the SGSN (Serving GPRS Support Node) in the Packet Switched Core Network. Interfaces The logical connections between the network elements are known as interfaces. The interface between the RNC and the Circuit Switched Core Network (CS-CN) is called Iu-CS and between the RNC and the Packet Switched Core Network is called Iu-PS. Other interfaces include Iub (between the RNC and the Node B) and Iur (between RNCs in the same network). Iu interfaces carry user traffic (such as voice or data) as well as control information (see ), and Iur interface is ... [...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] |
Engineering Optimization
Engineering optimization is the subject which uses optimization techniques to achieve design goals in engineering. It is sometimes referred to as design optimization. Topics * structural design (including pressure vessel design and welded beam design) * shape optimization * topology optimization (including airfoils) * inverse optimization (a subset of the inverse problem) * processing planning * product designs * electromagnetic optimization * space mapping * aggressive space mappingJ.E. Rayas-Sanche"Power in simplicity with ASM: tracing the aggressive space mapping algorithm over two decades of development and engineering applications" IEEE Microwave Magazine, vol. 17, no. 4, pp. 64-76, April 2016. * yield-driven design * optimization exploiting surrogates (surrogate model A surrogate model is an engineering method used when an outcome of interest cannot be easily measured or computed, so a model of the outcome is used instead. Most engineering design problems require experi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invoice
An invoice, bill or tab is a commerce, commercial document issued by a sales, seller to a buyer relating to a sale transaction and indicating the product (business), products, quantities, and agreed-upon prices for products or Service (economics), services the seller had provided the buyer. Discounts and allowances, Payment terms are usually stated on the invoice. These may specify that the buyer has a maximum number of days to pay and is sometimes offered a discount if paid before the due date. The buyer could have already paid for the products or services listed on the invoice. To avoid confusion and consequent unnecessary communications from buyer to seller, some sellers clearly state in large and capital letters on an invoice whether it has already been paid. From a seller's point of view, an invoice is a ''sales invoice''. From a buyer's point of view, an invoice is a ''purchase invoice''. The document indicates the buyer and seller, but the term ''invoice'' indicates mone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Authorization
Authorization or authorisation (see spelling differences) is the function of specifying access rights/privileges to resources, which is related to general information security and computer security, and to access control in particular. More formally, "to authorize" is to define an access policy. For example, human resources staff are normally authorized to access employee records and this policy is often formalized as access control rules in a computer system. During operation, the system uses the access control rules to decide whether access requests from (authenticated) consumers shall be approved (granted) or disapproved (rejected). Resources include individual files or an item's data, computer programs, computer devices and functionality provided by computer applications. Examples of consumers are computer users, computer software and other hardware on the computer. Overview Access control in computer systems and networks rely on access policies. The access control process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
