Pdf on mar 1, 2010, utsho a arefin and others published a study of cell site planning of gsm. Transcoder and rate adaptation unit, or trau, performs transcoding function for speech channels and ra rate adaptation for data channels in the gsm network. Additional components of the gsm architecture include databases and messaging systems functions. Figure 1 gives an simplified view of the network architecture with the three main network elements bts, bsc and msc. Transcoder and adaptation unit trau following is the diagram of gsm netwrok along with added elements. Gsm operates on the mobile communication bands 900 mhz and 1800 mhz in most parts of the world.
The bss communicates with the network service switching nss center across the a interface. Temporal scalable mobile video communications based on an. 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. Day02 gsm network architecture cankaya universitesi. The gsm network can be divided into three broad parts. Next, it describes how to use the image transcoder api package. In gsm, the mobile phone is called mobile station ms. Objectiv upon es completion of this module the student should be able. The x2 interface is defined between two neighbour enbs. Gsm adjunct systems gsm standards define that certain adjunct or secondary systems work with gsm technology.
Transcoder at the edge is also part of the present document. As is shown in figure 2, the wztosvc transcoder is composed of a wz decoder concatenated with an svc encoder. The pstnisdn switch is a switch for 64 kbits voice. A transcoder according to the invention provides a more efficiently organised architecture in which the at least one transcoder processor, of which there may be many e. Four channels are combined in transcoder to provide 64 kbps channel within bss. Research open access temporal scalable mobile video.
Pdf on jan 1, 2009, jorg eberspacher and others published gsm architecture, protocols and services 3. Pdf a study of cell site planning of gsm system researchgate. Packet controlling unit pcu can be compared to trau function in gsm generally located in the bsc heart of the packet transmission in bss network allow the dynamic traffic allocation provide the radio resource management mechanism. Since msc is basically a pstnisdn switch its bitrate is still 64 kbits. Aimed at service providers and large enterprises, audiocodes mt offloads media transcoding from audiocodes sbcs handling large call volumes. The present document specifies the stage 2 description of the outofband transcoder control for speech services. A logical diagram for the architecture of the signalling links is given in figure 6. It is also known as the air interface or the radio link. The additional components of the gsm architecture comprise of databases and messaging systems functions. Bsc and trau does not demand specific environmental conditions to perform operations. History of cellular mobile radio and gsmglobal systems for mobile l early 1980s there was analog.
Transcoding free voice transmission in gsm and umts. A gsm network is composed of several functional entities, whose functions and interfaces are defined. Transcoders transcoder types in cisco unified communications manager administration. To enable an efficient transmission of digital speech information over the air interface, the digital speech signal is compressed. The gateway msc or gmsc the purpose of which is to query the hlr and determine the location of the subscriber. Gsm fr gsm efr ciscomediaterminationpoint wssvccmm transcoder failover and fallback. Aug 10, 2018 transcoder and rate adaptation unit, or trau, performs transcoding function for speech channels and ra rate adaptation for data channels in the gsm category education. Transcoder type description pernmhd thistype,whichsupportscisco2600xm,cisco2691,cisco3660. The ms and the bss communicate across the um interface. Gsm supports voice calls and data transfer speeds of up to 9. The bts base transceiver station is controlling the radio transmission and the interface to the mobile phones.
Mobile radio interface layer 3 specification core network protocols stage 3. Figure 8 the base station subsystem bss some of the most important bss tasks are listed in the following. Gsm network architecture, channelisation, signalling and call. It describes the principles and procedures to support transcoder free operation, tandem free operation and the interworking between trfo and tfo. The structure of a gsm network relies on several functional entities, which have been specified in terms of functions and interfaces. Gsm is a circuitswitched system that divides each 200 khz channel into eight 25 khz timeslots. In order to set up a requested call, the call is initially routed to a gateway msc, which finds the correct hlr by knowing the directory number of the gsm subscriber. The gsm service area is the entire gggpeographical area in which a subscriber. Cellular mobile systems and services tcom1010 2009april gsm architecture 1 gsm network infrastructure2 2 network switching subsystem nss 3 2. Gsm network architecture, channelisation, signalling and. Tail allzero bits to indicate the start and the end of the burst. Transcoders are used for a direct analogtoanalog or digitaltodigital conversation of one encoding to another. Reuse bss architecture new core architecture max theoretical rates 170 kbps gsm circuit switch architecture indirect access to ip network too sensitive connection for data today expensive solution for data network hscsd gsm circuit switch architecture indirect access to ip network too sensitive. Gsm global system for mobile communications is an open, digital cellular technology used.
The mobile radiotelephone system includes the following subsystems base station subsystem bss network and switching subsystem nss. Trau transcoder and rate adaptation unit is an entity to perform a transcoding function for speech channels and rarate adaptation for various data channels. Its function is the compress and decompress the speech between trau and ms. The ms is a combination of terminal equipment and subscriber. Global system for mobile gsm is a second generation cellular standard developed. The main task of gsm trau is to compress and decompress the speech data.
When the fcc issued 1900 mhz to pcs in the united states it was based on gsm. Each cell is given a cell global identity cgi, a number that uniquely identifies the cell. This is the area that is paged when a subscriber gets an incoming call. Transcoder and rate adaptation unit, or trau, performs transcoding function for speech channels and ra rate adaptation for data channels in the gsm category education. Gsm network areas in a gsm network, the following areas are defined. Gsm phases 1 and 2 define digital cellular telecommunications system. Overview of the gsm system and protocol architecture.
First, this document explains the basic transcoder api that transcoder, transcoderinput and transcoderoutput define, and thus all transcoders have in common. Gsm owns a market share of more than 70 percent of the worlds digital cellular subscribers. We stock a wide variety of transcoders, video converters, and other transcoder equipment. Tandem free operation tfo in gsm networks enables transmitting voice transparently trough the core network without transcoding. Transcoder and adaptation unit trau the following diagram shows the gsm network along with the added elements. Here is the summer training project in hutch on gsm architecture. Dcs 1900 is considered the gsm standard for north america and is called north american gsm. In the proposed architecture, the mvs are temporally stored in a buffer and sent to the motion prediction module of svc, where they are processed as described in the following sections. Gsm uses digital communication system or dcs 1800 and is the worlds main 2g standard. The transcoderrate adaptation unit trau is the data rate conversion unit. In the us, gsm operates in the bands 850 mhz and 1900 mhz.
Gsm global system for mobile communications is an open, digital cellular technology used for transmitting mobile voice and data services. Architecture a gsm network consists of several functional entities, whose functions and interfaces are. Eng page 2 of 7 1 gsm network infrastructure the following figure depicts a typical gsm network called, public. Functional architecture and principal interfaces gateway msc gmsc. The mobile station ms the base station subsystem bss the network switching subsystem nss the operation support subsystem oss below is a simple graphical view of the gsm architecture. Gsm overview warmly welcome to bundle of my wisdom nifrash. Cellular and mobile communications questions answers. Transcoding in gsm bss transcoder does conversion of g. Gsm global system for mobile communication is one of the most popular system used for mobile telecommunications especially in europe and asia. A mobile transmits and receives messages to and from the gsm system over the air interface to establish and continue connections through the system 2. 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. Gsm architecture in gsm tutorial 18 april 2020 learn gsm. The bss carries out transcoding of speech channels, allocation of radio channels to mobile phones, paging, transmission and reception. The terminal equipment as such is called me mobile.
In the gsm network, the base station subsystem bss is the part of the network taking care of radio resources, that is, radio channel allocation and quality of the radio connection. Gprs tunnelling protocol for the user plane gtpu tunnels user data between enodeb and the sgw as well as between the sgw and the pgw in the backbone network. Trau, referred as transcoding rate and adaptation unit is located as shown in the figure below between bsc and msc or between bts and bsc. It involves three main subsystems, each containing functional units and interconnected with the others through a series of standard interfaces. Equipment and the subscribers data is stored in a separate. Isolates calls, a graphical call flow diagram can be created from a call trace. The transcoder tc thus takes care of the change from one bit rate to another. Trau one of the most interesting features of gsm is trau.
Global system for mobile communications gsm is a digital wireless network standard. The audiocodes media transcoder mt solution delivers high capacity dspbased transcoding in conjunction with audiocodes fieldproven hardwarebased sbc product family. Mobility management and speech transcoding bss mobility management mainly covers the different cases of handovers. These functions and interfaces are explained in this chapter. It was developed by group special mobile of conference europeenne des postes et telecommunications cept and european telecommunications standards institute etsi. Find, read and cite all the research you need on researchgate. Gsm architecture mobile telecommunications networks. Given below is a simple pictorial view of the gsm architecture. The mobile station is carried by the subscriber, the base station subsystem controls the. Current technology permits to decrease the bitrate in gsm radio interface it is 16 kbits for full rate and 8 kbits for half rate. A study on call site planning of gsm system from the users point of view, the sim is certainly the bestknown database used in a gsm network.