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.
19-621: 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 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,
38-474: A baseband unit (BBU) is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets), WLL phones, computers with wireless Internet connectivity, or antennas mounted on buildings or telecommunication towers. The network can be that of any of the wireless communication technologies like GSM, CDMA, wireless local loop, Wi-Fi, WiMAX or other wide area network (WAN) technology. BTS
57-813: A spherical radiation pattern. Omnidirectional antennas oriented vertically are widely used for nondirectional antennas on the surface of the Earth because they radiate equally in all horizontal directions, while the power radiated drops off with elevation angle so little radio energy is aimed into the sky or down toward the earth and wasted. Omnidirectional antennas are widely used for radio broadcasting antennas, and in mobile devices that use radio such as cell phones , FM radios , walkie-talkies , wireless computer networks , cordless phones , GPS , as well as for base stations that communicate with mobile radios, such as police and taxi dispatchers and aircraft communications. The most common omnidirectional antenna designs are
76-435: A 'circular aerial' because of the shape) and the halo antenna . Higher-gain omnidirectional antennas can also be built. "Higher gain" in this case means that the antenna radiates less energy at higher and lower elevation angles and more in the horizontal directions. High-gain omnidirectional antennas are generally realized using collinear dipole arrays . These consist of multiple half-wave dipoles mounted collinearly (in
95-571: A line), fed in phase. The coaxial collinear (COCO) antenna uses transposed coaxial sections to produce in-phase half-wavelength radiators. A Franklin Array uses short U-shaped half-wavelength sections whose radiation cancels in the far-field to bring each half-wavelength dipole section into equal phase. Another type is the Omnidirectional Microstrip Antenna (OMA). Omnidirectional radiation patterns are produced by
114-416: A separate direction of tracking, typically of 120° with respect to the adjacent ones. Other orientations may be used to suit the local conditions. Bisectored cells are also implemented. These are most often oriented with the antennas serving sectors of 180° separation to one another, but again, local variations do exist. Omnidirectional antenna In radio communication , an omnidirectional antenna
133-440: Is a class of antenna which radiates equal radio power in all directions perpendicular to an axis ( azimuthal directions), with power varying with angle to the axis ( elevation angle ), declining to zero on the axis. When graphed in three dimensions (see graph) this radiation pattern is often described as doughnut-shaped . This is different from an isotropic antenna , which radiates equal power in all directions, having
152-461: Is also referred to as the node B (in 3G networks) or, simply, the base station (BS). For discussion of the LTE standard the abbreviation eNB for evolved node B is widely used, and GNodeB for 5G. Though the term BTS can be applicable to any of the wireless communication standards, it is generally associated with mobile communication technologies like GSM and CDMA. In this regard, a BTS forms part of
171-402: 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 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
190-401: The monopole antenna , consisting of a vertical rod conductor mounted over a conducting ground plane , and vertical dipole antenna , consisting of two collinear vertical rods. The quarter-wave monopole and half-wave dipole both have vertical radiation patterns consisting of a single broad lobe with maximum radiation in horizontal directions, so they are popular. The quarter-wave monopole,
209-458: The BTS remains the same regardless of the wireless technologies. A BTS is usually composed of: Directional antennas reduce LoRa (long-range) interference. If not sectorised, the cell will be served by an omnidirectional antenna , which radiates in all directions. A typical structure is the trisector, also known as clover, in which there are three sectors served by separate antennas. Each sector has
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#1732794391395228-444: The base station subsystem (BSS) developments for system management. It may also have equipment for encrypting and decrypting communications, spectrum filtering tools (band pass filters) and so on. Antennas may also be considered as components of BTS in general sense as they facilitate the functioning of BTS. Typically a BTS will have several transceivers (TRXs) which allow it to serve several different frequencies and different sectors of
247-441: 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 a very popular deployment). Base transceiver station A base transceiver station ( BTS ) or
266-491: The cell (in the case of sectorised base stations). A BTS is controlled by a parent base station controller via the base station control function (BCF). The BCF is implemented as a discrete unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance (O&M) connection to the network management system (NMS), and manages operational states of each TRX, as well as software handling and alarm collection. The basic structure and functions of
285-573: 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 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
304-591: The most compact resonant antenna, may be the most widely used antenna in the world. The five-eighth wave monopole, with a length of 5 / 8 = 0.625 {\displaystyle 5/8=0.625} of a wavelength, is also popular because at that length a monopole radiates maximum power in horizontal directions. Common types of low-gain omnidirectional antennas are the whip antenna , "Rubber Ducky" antenna , ground plane antenna , vertically oriented dipole antenna , discone antenna , mast radiator , horizontal loop antenna (sometimes known colloquially as
323-532: 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 (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
342-425: 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 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
361-470: The simplest practical antennas, monopole and dipole antennas , consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by antenna directivity (D) which is expressed mathematically as: G = e D {\displaystyle G=eD} . A useful relationship between omnidirectional radiation pattern directivity (D) in decibels and half-power beamwidth (HPBW) based on
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