Node B is the telecommunications node for mobile communication networks, namely those that adhere to the UMTS standard. The Node B provides the connection between mobile phones ( UEs ) and the wider telephone network. UMTS is the dominating 3G standard.
9-779: 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 (RNCs) which make up the Universal Mobile Telecommunications System (UMTS) radio access network . This communications network, commonly referred to as 3G (for 3rd Generation Wireless Mobile Communication Technology), can carry many traffic types from real-time Circuit Switched to IP based Packet Switched . The UTRAN allows connectivity between
18-488: Is changing with the emergence of High Speed Downlink Packet Access ( HSDPA ), where some logic (e.g., retransmission) 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 even controlled by different RNC to overlap and still use the same frequency (in fact, the whole network can be implemented with just one frequency pair ). The effect
27-420: Is utilized in soft handovers . Since WCDMA often operates at higher frequencies than GSM (2,100 MHz as opposed to 900 MHz for GSM), the cell radius can be considerably 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
36-720: The Radio Network Subsystem (RNS). 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 that connects the RNC to the Core Network (CN). The Uu is also external, connecting Node B with the User Equipment (UE). The Iub is an internal interface connecting
45-548: The UE (user equipment) and 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 that is 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
54-604: The RNC with Node B. And at last, there is the Iur interface, which is 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. Node B Node B corresponds to BTS ( base transceiver station ) in GSM . This is the hardware that is 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
63-609: The air interface technology. As in all cellular systems, such as UMTS and GSM , the Node B contains radio frequency transmitter(s) and the receiver(s) used to communicate directly with mobile devices, which move freely 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, and are controlled by an RNC ( Radio Network Controller ). However, this
72-594: The equivalent GSM network. Unlike in GSM, the cells' size is not constant (a phenomenon known as " cell breathing "). This requires a larger number of Node Bs and careful planning in 3G ( UMTS ) networks. Power requirements on Node Bs and user equipment (UE) are much lower. It is connected to RNC of UMTS network through IUB interface. A full cell site has a cabinet, 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
81-478: The side of a road or in a city center is just an antenna. However, the tendency nowadays is to camouflage the antenna (paint it the color of the building or put it into an RF-transparent enclosure). Smaller indoor nodes may have an antenna built into the cabinet door. A Node B can serve several cells, also called sectors, depending on the configuration and type of antenna. Common configuration include omni cell (360°), 3 sectors (3×120°) or 6 sectors (60 degree each, not
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