From Wikipedia, the free encyclopedia
A base transceiver station (BTS) or cell site 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, WiFi and WiMAX gadgets etc. The network can be that of any of the wireless communication technologies like GSM, CDMA, WLL, WAN, WiFi, WiMAX etc.BTS is also referred to as the radio base station (RBS), 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.
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[edit] BTS in Mobile Communication
A GSM network is made up of three subsystems:- The Network and Switching Subsystem (NSS) – comprising an MSC and associated registers.
- The Base Station subsystem (BSS) – comprising a BSC and several BTSes
- The Operations support system - for maintenance of the network.
General Architecture
A BTS in general has the following parts:- Transceiver (TRX)
- Quite widely referred to as the driver receiver (DRX). DRX are either in the form of single (sTRU), double(dTRU) or a composite Double Radio Unit (DRU). It basically does transmission and reception of signals. Also does sending and reception of signals to/from higher network entities (like the base station controller in mobile telephony).
- Power amplifier (PA)
- Amplifies the signal from DRX for transmission through antenna; may be integrated with DRX.
- Combiner
- Combines feeds from several DRXs so that they could be sent out through a single antenna. Allows for a reduction in the number of antenna used.
- Duplexer
- For separating sending and receiving signals to/from antenna. Does sending and receiving signals through the same antenna ports (cables to antenna).
- Antenna
- This is also considered a part of the BTS.
- Alarm extension system
- Collects working status alarms of various units in the BTS and extends them to operations and maintenance (O&M) monitoring stations.
- Control function
- Control and manages the various units of BTS including any software. On-the-spot configurations, status changes, software upgrades, etc. are done through the control function.
- Baseband receiver unit (BBxx)
- Frequency hopping, signal DSP, etc.
Terms regarding a mobile BTS
- Diversity techniques
- To improve the quality of the received signal, often two receiving antennas are used, placed at an equal distance to an uneven multiple of a quarter of wavelength (for 900 MHz the wavelength it is 30 cm). This technique, known as antenna diversity or space diversity, avoids interruption caused by path fading. The antennas can be spaced horizontally or vertically. Horizontal spacing requires more complex installation, but brings better performance.
- Other than antenna or space diversity, there are other diversity techniques such as frequency/time diversity, antenna pattern diversity, and polarization diversity.
- Splitting refers to the flow of power within a particular area of the cell, known as sector. Every field can therefore be considered like one new cell.
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