UMTS Terrestrial Radio Access Network
UTRAN is a collective term for the network and equipment that connects mobile handsets to the public telephone network or the Internet. It contains the base stations, which are called Node B's and Radio Network Controllers which make up the UMTS radio access network; this communications network referred to as 3G, can carry many traffic types from real-time Circuit Switched to IP based Packet Switched. The UTRAN allows connectivity between the core network; the RNC provides control functionalities for one or more Node Bs. A Node B and an RNC can be the same device, although typical implementations have a separate RNC located in a central office serving multiple Node Bs. Despite the fact that they do not have to be physically separated, there is a logical interface between them known as the Iub; the RNC and its corresponding Node Bs are called the Radio Network Subsystem. There can be more than one RNS present in a UTRAN. There are four interfaces connecting the UTRAN internally or externally to other functional entities: Iu, Uu, Iub and Iur.
The Iu interface is an external interface. The Uu is external, connecting the Node B with the User Equipment; the Iub is an internal interface connecting the RNC with the Node B. And at last there is the Iur interface, an internal interface most of the time, but can, exceptionally be an external interface too for some network architectures; the Iur connects two RNCs with each other. UMTS - Universal Mobile Telecommunications System GERAN - GSM EDGE Radio Access Network
Telecommunication is the transmission of signs, messages, writings and sounds or information of any nature by wire, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology, it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is used in its plural form because it involves many different technologies. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, optical heliographs. Other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, loud whistles. 20th- and 21st-century technologies for long-distance communication involve electrical and electromagnetic technologies, such as telegraph and teleprinter, radio, microwave transmission, fiber optics, communications satellites.
A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse, Alexander Graham Bell, Edwin Armstrong and Lee de Forest, as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth; the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, the Latin communicare, meaning to share. Its modern use is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié. Communication was first used as an English word in the late 14th century, it comes from Old French comunicacion, from Latin communicationem, noun of action from past participle stem of communicare "to share, divide out.
Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots, was used by the Romans to aid their military. Frontinus said; the Greeks conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Sumatra, and in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, chains of beacons were used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London. In 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris.
However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres. As a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. On 25 July 1837 the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke, English scientist Sir Charles Wheatstone. Both inventors viewed their device as "an improvement to the electromagnetic telegraph" not as a new device. Samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837, his code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was completed on 27 July 1866, allowing transatlantic telecommunication for the first time; the conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849.
However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. Starting in 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using the newly discovered phenomenon of radio waves, showing by 1901 that they could be transmitted across the Atlantic Ocean; this was the start of wireless telegraphy by radio. Voice and music had little early success. World War I accelerated the development of radio for military communications. After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated development of radio for the wartime purposes of aircraft and land communication, radio navigation and radar. Development of stereo FM broadcasting of radio
Radio Network Controller
The Radio Network Controller is a governing element in the UMTS radio access network 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 and to the SGSN in the Packet Switched Core Network. The logical connections between the network elements are known as interfaces; the interface between the RNC and the Circuit Switched Core Network is called Iu-CS and between the RNC and the Packet Switched Core Network is called Iu-PS. Other interfaces include Iur. Iu interfaces carry user traffic as well as control information, Iur interface is needed for soft handovers involving 2 RNCs though not required as the absence of Iur will cause these handovers to become hard handovers; until 3gpp R4, all the interfaces in the UTRAN are implemented using ATM only, except the Uu interface which uses WCDMA technology.
Starting R5, IP bearers can be used over Ethernet instead. Physically, these interfaces can be carried over SDH over optical fiber, E1 - over a copper wire or microwave radio. Several E1s can be bundled to form an IMA Group. Since the interfaces are logical, many interfaces can be multiplexed onto the same transmission line; the actual implementation depends on the network topology. Iub, Iu and Iur protocols all carry both user data and signalling. Signalling protocol responsible for the control of the Node B by the RNC is called NBAP. NBAP is subdivided into Common and Dedicated NBAP, where Common NBAP controls overall Node B functionality and Dedicated NBAP controls separate cells or sectors of the Node B. NBAP is carried over Iub. In order for NBAP to handle common and dedicated procedures, it is divided into: NodeB Control Port which handles common NBAP procedures and Communication Control Port which handles dedicated NBAP procedures. Control plane protocol for the transport layer is called ALCAP.
Basic functionality of ALCAP is multiplexing of different users onto one AAL2 transmission path using channel IDs. ALCAP is carried over Iu-CS interfaces. Signalling protocol responsible for communication between RNC and the core network is called RANAP, is carried over Iu interface. Signalling protocol responsible for communications between RNCs is called RNSAP and is carried on the Iur interface. In a relationship to a UE an RNC can play two different roles; these are: D-RNC: Drift RNC S-RNC: Serving RNCHowever, as far as the NodeB is concerned, the RNC may play a third role: C-RNC: Controlling RNCIt is important to know that one RNC can assume more than one role at any time. An RNC controls the power of a NodeB. Operations and Maintenance Centre Radio Resource Control UMTS NBAP Specifications RANAP Specifications RNSAP Specifications RRC Specifications
Node B is the telecommunications node in particular mobile communication networks, namely those that adhere to the UMTS standard. The Node B provides the connection between the wider telephone network. UMTS is the dominating 3G standard. Node B corresponds to BTS in GSM; this is the hardware, connected to the mobile phone network that communicates directly with mobile handsets. In contrast with GSM base stations, Node B uses WCDMA/TD-SCDMA as the air interface technology; as in all cellular systems, such as UMTS and GSM, the Node B contains radio frequency transmitter and the receiver used to communicate directly with mobile devices, which move around it. In this type of cellular network, the mobile devices cannot communicate directly with each other but have to communicate with the NodeB. Traditionally, the Node Bs have minimum functionality, are controlled by an RNC. However, this is changing with the emergence of High Speed Downlink Packet Access, where some logic is handled on the Node B for lower response times.
The utilization of WCDMA technology allows cells belonging to the same or different Node Bs and controlled by different RNC to overlap and still use the same frequency. The effect is utilized in soft handovers. Since WCDMA operates at higher frequencies than GSM, the cell radius can be smaller for WCDMA than for GSM cells as the path loss is frequency dependent. WCDMA now has networks operating in the 850–900 MHz band. In these networks, at these frequencies, the coverage of WCDMA is considered better than that of the equivalent GSM network. Unlike in GSM, the cells' size is not constant; this requires careful planning in 3G networks. Power requirements on Node Bs and user equipment are much lower, it is connected to RNC of UMTS network through IUB interface. A full cell site has an antenna mast and actual antenna. An equipment cabinet contains e.g. RF power amplifiers, digital signal processors and backup batteries. What you can see by the side of a road or in a city center is just an antenna. However, the tendency nowadays is to camouflage the antenna.
Smaller indoor nodes may have an antenna built into the cabinet door. A Node B can serve several cells called sectors, depending on the configuration and type of antenna. Common configuration include 3 sectors or 6 sectors. ENode B NBAP HSDPA