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GSMGSM ((EnglishEnglish: Global System for Mobile : Global System for Mobile

Communication. Abbreviation: GSM) Is a Communication. Abbreviation: GSM) Is a technology used for Mobile network. GSM technology used for Mobile network. GSM service used by more than 2 billion people in service used by more than 2 billion people in 212 countries and territories. The GSM network 212 countries and territories. The GSM network may allow roaming together so that the device's may allow roaming together so that the device's GSM mobile networks in different GSM can be GSM mobile networks in different GSM can be used many places in the world.used many places in the world.

GSM is the most common standard for mobile GSM is the most common standard for mobile (Cell phone) in the world. Wide coverage (Cell phone) in the world. Wide coverage capabilities of the GSM standard which makes it capabilities of the GSM standard which makes it so popular in the world, allowing users to use so popular in the world, allowing users to use their mobile phones in many parts of the world. their mobile phones in many parts of the world. GSM differs from the standard of its predecessor GSM differs from the standard of its predecessor on the signal and speed, call quality. It was seen on the signal and speed, call quality. It was seen as a system of second-generation mobile phones as a system of second-generation mobile phones (second generation, 2G). (second generation, 2G).

Structure and Function of the components in the Structure and Function of the components in the GSM networkGSM network

Mobile Station(MS)Mobile Station(MS)+ SIM+ SIM+ Mobile Equipment+ Mobile Equipment

Base Station SubSytems(BSS)Base Station SubSytems(BSS)+ BTS+ BTS+ BSC+ BSC+ PCU(GPRS)+ PCU(GPRS)

Network SubSystem (NSS)Network SubSystem (NSS)+ MSC+ MSC+ HLR+ HLR+ VLR+ VLR+ EIR+ EIR+ SGSN(GPRS)+ SGSN(GPRS)

Operation and Support System (OSS)+NNC+NNC+OMC+OMC

Architecture of the GSM Architecture of the GSM network network

Architecture of the GSM Architecture of the GSM network network

1.Mobile Station1.Mobile Station

Mobile station (MS), including mobile Mobile station (MS), including mobile phones and smart card authentication phones and smart card authentication subscriber (SIM). SIM provides personal subscriber (SIM). SIM provides personal mobility so users can mount your SIM mobility so users can mount your SIM into any GSM mobile phone access into any GSM mobile phone access service that has been registeredservice that has been registered

MS=ME+SIMMS=ME+SIM+ME (Mobile Equipment)+ME (Mobile Equipment)+SIM (Subscriber Identity Module )+SIM (Subscriber Identity Module )

Structure and meaning of IMEIStructure and meaning of IMEI

IMEIIMEI (International Mobile Equipment Identity) (International Mobile Equipment Identity)-IMEI numbers are 15 digits including by format:-IMEI numbers are 15 digits including by format:

NNXXXX-YY-ZZZZZZ-ANNXXXX-YY-ZZZZZZ-A..+NN+NN: The first digit of the IMEI is called : The first digit of the IMEI is called Reporting Body Identifier (BABT)Reporting Body Identifier (BABT)+XXXX: The next four digits are called Type +XXXX: The next four digits are called Type Mobile Equipment Identifier, used to identify Mobile Equipment Identifier, used to identify categories (model) cell phonecategories (model) cell phone+YY: Two numbers are called FAC (Final +YY: Two numbers are called FAC (Final Assembly Code)Assembly Code)+ZZZZZZ: series of product.+ZZZZZZ: series of product.+A: (Check Digit) use to check. This number is +A: (Check Digit) use to check. This number is based on 14 digits stated in a given algorithm. based on 14 digits stated in a given algorithm. Can be based on the IMEI number to the number Can be based on the IMEI number to the number is valid or notis valid or not+press *#06# to check IMEI+press *#06# to check IMEI

1.Mobile Station (cont)1.Mobile Station (cont)

- SIM (Subscriber Identity Module) . - SIM (Subscriber Identity Module) . Including recording information Including recording information about your phone number (including about your phone number (including subscription, PIN numbers, the subscription, PIN numbers, the activation code and working activation code and working programs built connect to the programs built connect to the Mobile switching center to use and Mobile switching center to use and provides services ...), you can store provides services ...), you can store messages or contacts on it.messages or contacts on it.

2.Base Station 2.Base Station SubSytemsSubSytems (BSS) (BSS)

*BTS (Base Transceiver Station) BTS is a device between the GSM

network and subscriber device MS, BTS implementation the following functions:

transmit and receive radio waves Mapping logical channels to physical

channels Coding / Decoding Ciphering / Deciphering Modulating / Demodulating

BTSBTS

BSS (cont)BSS (cont)

*BSC (Base Station Controller) BSCBSC has the duty to manage all wireless has the duty to manage all wireless

interfaces BTS and MS through the remote interfaces BTS and MS through the remote control commands. These commands are control commands. These commands are primarily assigned order, release and primarily assigned order, release and transfer of radio channels.transfer of radio channels.

A BSC is connected to the BTS Abis A BSC is connected to the BTS Abis interface, also connected to the operator interface, also connected to the operator side MSC interface A. In fact, the BSC is side MSC interface A. In fact, the BSC is considered as a small switchboard, capable considered as a small switchboard, capable of computation significantly. Its main role of computation significantly. Its main role is to manage the wireless channel at the is to manage the wireless channel at the interface and transfer. Typically a BSC is interface and transfer. Typically a BSC is connected with axes hundreds BTS. connected with axes hundreds BTS.

BSS (cont)BSS (cont) TRAUTRAU (Transcoder and Rate Adapter Unit) (Transcoder and Rate Adapter Unit)

Perform code conversion information from Perform code conversion information from the radio channel (16 Kb / s) standard The the radio channel (16 Kb / s) standard The standard GSM voice channels (64 Kb / s) standard GSM voice channels (64 Kb / s) before moving to the operator. before moving to the operator.

TRAU is a device where the process of TRAU is a device where the process of encoding and decoding language encoding and decoding language characteristics for GSM conducted, there is characteristics for GSM conducted, there is also implementing adaptation speed in case also implementing adaptation speed in case of transmission materials. of transmission materials.

TRAU is part of the BTS, but also can be TRAU is part of the BTS, but also can be placed away from BTS and even only place placed away from BTS and even only place in the BSC and MSCin the BSC and MSC

* * MSCMSC (Mobile switching center (Mobile switching center))- MSC to perform the tasks set up coordination - MSC to perform the tasks set up coordination

calls to users of GSM network with each other calls to users of GSM network with each other and with other networks. MSC made to and with other networks. MSC made to communicate with the BSS system and communicate with the BSS system and communicate with outside networks. MSC communicate with outside networks. MSC made to communicate with networks outside made to communicate with networks outside the gate called MSC (GMSC).the gate called MSC (GMSC).

- MSC to connect to a network needs to adapt - MSC to connect to a network needs to adapt the transmission characteristics of the GSM the transmission characteristics of the GSM networks is called the interactive features networks is called the interactive features IWF (Interworking Funtions). IWF includes a IWF (Interworking Funtions). IWF includes a device to adapt protocols and transmission. It device to adapt protocols and transmission. It allows connecting to the ISDN network, allows connecting to the ISDN network, PSPDN, PSTN ...PSPDN, PSTN ...

3.Network Switching SubSystem 3.Network Switching SubSystem (NSS)(NSS)

GMSC gateway mobile switchboard: GMSC gateway mobile switchboard: All calls to the GSM / PLMN to be routed to the All calls to the GSM / PLMN to be routed to the

operator wireless gateway GMSC. If someone in operator wireless gateway GMSC. If someone in the fixed network PSTN to make a call to a the fixed network PSTN to make a call to a subscriber's mobile GSM / PLMN. Switchboard in subscriber's mobile GSM / PLMN. Switchboard in PSTN will connect the call to MSC is equipped PSTN will connect the call to MSC is equipped with a function called port function. Switchboard with a function called port function. Switchboard MSC is called the gateway MSC and the MSC can MSC is called the gateway MSC and the MSC can be any of a GSM network. GMSC will have to find be any of a GSM network. GMSC will have to find the location of MS looking for. This is done by the location of MS looking for. This is done by asking where MS HLR registration. HLR will asking where MS HLR registration. HLR will respond, then the MSC may be routing calls to respond, then the MSC may be routing calls to the MSC Left necessary. When the call to MSC, the MSC Left necessary. When the call to MSC, the VLR will know more details about the location the VLR will know more details about the location of MS. Such information can connect a call in the of MS. Such information can connect a call in the GSM network is the difference between device GSM network is the difference between device physics and subscribe. physics and subscribe.

NSS (cont)NSS (cont)

NSS NSS (cont)(cont)

*EIR*EIR (Equipment identity register) (Equipment identity register) EIR is connected to the MSC via a signal line, EIR has EIR is connected to the MSC via a signal line, EIR has

the function to check the validity of the mobile device the function to check the validity of the mobile device (ME) through data to identify international mobile (ME) through data to identify international mobile (IMEI) and contains data on hardware device.(IMEI) and contains data on hardware device.

ME in one of the three lists below: ME in one of the three lists below:

- White : News it was access to and use of - White : News it was access to and use of services registered. services registered.

- gray: that is a question and need to - gray: that is a question and need to check.check.

- Black : that is prohibited or fails does not - Black : that is prohibited or fails does not allow allow access to the network. access to the network.

NSS (cont)

AuC (Authentication Centre) AUC is connected to the HLR, the AUC AUC is connected to the HLR, the AUC

function is to provide the HLR frequencies function is to provide the HLR frequencies eclipse and encryption key to use for security. eclipse and encryption key to use for security. Street wireless AUC also provides security Street wireless AUC also provides security code to protect against eavesdropping, this code to protect against eavesdropping, this code is changed for each individual code is changed for each individual subscriber. Database of AUC recorded many subscriber. Database of AUC recorded many other necessary information when subscribers other necessary information when subscribers sign up in the network and used to test the sign up in the network and used to test the subscriber requests service providers, network subscriber requests service providers, network access prevent an unauthorized manner. access prevent an unauthorized manner.

NSS (cont) HLR (Home Location Register)

HLR database is the most important of the HLR database is the most important of the GSM system. In GSM each activity stored GSM system. In GSM each activity stored data along with information on all data along with information on all subscribers. The data stored data can be subscribers. The data stored data can be performed on one or more HLR. performed on one or more HLR.

HLR data store all information relating to HLR data store all information relating to the provision of telecommunications the provision of telecommunications services, including the current location of services, including the current location of MS. MS.

HLR usually a separate computer is not able HLR usually a separate computer is not able to switch but have the ability to manage to switch but have the ability to manage hundreds of thousands of subscribers. HLR hundreds of thousands of subscribers. HLR also create the No. 7 signaling interface with also create the No. 7 signaling interface with the MSC. More a function of HLR identifying the MSC. More a function of HLR identifying information is provided by the AUC (data information is provided by the AUC (data security on the legitimacy of the charter).security on the legitimacy of the charter).

NSS (cont) VLR (Visitor Location Register)

VLR is the database the second GSM mobile VLR is the database the second GSM mobile network. It is connected to one or more MSC network. It is connected to one or more MSC and duties temporarily stored subscriber and duties temporarily stored subscriber data of subscriber MS is located in the area data of subscriber MS is located in the area served by MSC, respectively, even MS served by MSC, respectively, even MS mobility to a new MSC area. mobility to a new MSC area.

VLR associated with the MSC will request VLR associated with the MSC will request data on MS from the HLR, HLR will also be data on MS from the HLR, HLR will also be informed that the MS is in the MSC does. informed that the MS is in the MSC does. Then if MS want to make a call, the VLR will Then if MS want to make a call, the VLR will have all the information needed to establish have all the information needed to establish a call without HLR again. a call without HLR again.

VLR can be considered as a distributed HLR. VLR can be considered as a distributed HLR. VLR contains more precise information VLR contains more precise information about the location HLR MS in the MSC about the location HLR MS in the MSC

4.Operation and Support System (OSS)

NMC (Network Management Center) is NMC (Network Management Center) is located in the heart of the system, located in the heart of the system, responsible for providing management responsible for providing management functions for the entire network. functions for the entire network. - Monitoring the nodes in the network - Monitoring the nodes in the network - Monitoring the status of parts of the - Monitoring the status of parts of the networknetwork- Monitoring and maintenance center - Monitoring and maintenance center OMC and exploitation of the region and OMC and exploitation of the region and provide information to other parts of provide information to other parts of OMC OMC

OSS (cont) OMC (operation Maintenance Center)

- OMC provides key features to control and monitor the part of the network (the BTS, MSC, the database ...). OMC has the functions:

+ management warning+incident management,+quality management+ configuration management + security management

BSSBSS

PCUPCU ( (Packet Control UnitPacket Control Unit) A ) A component is integrated into each component is integrated into each BSC to control channels of packet BSC to control channels of packet data GPRS technology, separate data GPRS technology, separate data circuit switched data packet data circuit switched data packet switching switching

SGSN(GPRS)SGSN(GPRS) SGSN (Serving GPRS Support Node) SGSN (Serving GPRS Support Node)

responsible for distribution and responsible for distribution and distributed routing data packets distributed routing data packets between handsets and MS data between handsets and MS data networks outside. SGSN not only networks outside. SGSN not only routing data packets between the routing data packets between the mobile MS and the gateway GPRS mobile MS and the gateway GPRS support node - GGSN but registration support node - GGSN but registration for the mobile GPRS appear in the for the mobile GPRS appear in the service of it. service of it.

GSM FrequencyGSM Frequency GSM system work in bands 890 - 960MHz. GSM system work in bands 890 - 960MHz.

Band is divided into two parts: Band is divided into two parts: - Operating frequency up (Uplink band): 890-- Operating frequency up (Uplink band): 890-915 MHz for the radio channel from mobile 915 MHz for the radio channel from mobile station to base transceiver station system. station to base transceiver station system. - Operating frequency down (Downlink band): - Operating frequency down (Downlink band): 935-960 MHz for the radio channel from the 935-960 MHz for the radio channel from the base transceiver station to mobile stationbase transceiver station to mobile station

Band is divided into 124 channels with a Band is divided into 124 channels with a bandwidth of 25MHz. each channel a bandwidth of 25MHz. each channel a separated about 200 Khz. Duplex distance (up separated about 200 Khz. Duplex distance (up & down the road for a subscription) is & down the road for a subscription) is

45MHz.45MHz.

GSM FrequencyGSM Frequency

CHANNELCHANNEL

- The physical channel is a timeslot in a - The physical channel is a timeslot in a dedicated radio frequency to transmit dedicated radio frequency to transmit information in the way of the GSM radio. information in the way of the GSM radio. Each radio frequency channel is organized Each radio frequency channel is organized into TDMA frame length of 4.62 ms has 8 into TDMA frame length of 4.62 ms has 8 time slots (one slot length 577μ s)time slots (one slot length 577μ s)

- The logical channel is characterized by - The logical channel is characterized by information transmission between the BTS information transmission between the BTS and MS. The logical channel is placed above and MS. The logical channel is placed above the physical channel. Logical channels can the physical channel. Logical channels can be divided into two types of channels: traffic be divided into two types of channels: traffic channels (TCH) and control channel signalchannels (TCH) and control channel signal

interface in GSM networkinterface in GSM network

BSC BTSA bit

MSC BSCA

MSC VLRB

VLR VLRG

MSC MSCE

MSC EIRF

BTS MSUm

FDMA,TDMA,CDMAFDMA,TDMA,CDMA FDMA - Frequency Division Multiple Access FDMA - Frequency Division Multiple Access

Concept: FDMA is a multiple access method Concept: FDMA is a multiple access method in which each subscriber is allocated a in which each subscriber is allocated a frequency channel and determined that only frequency channel and determined that only subscribers have the right to use this subscribers have the right to use this channel during contact. (Qualcomm, 1997)channel during contact. (Qualcomm, 1997)

TDMA is an abbreviation of the word "Time TDMA is an abbreviation of the word "Time Division Multiple Access" This is a Division Multiple Access" This is a technology that allows eight mobile device technology that allows eight mobile device can use a common channel for conversation, can use a common channel for conversation, each will use the eighth time slot to transmit each will use the eighth time slot to transmit and receive information. and receive information.

CDMACDMA (full article is (full article is Code Division Multiple Code Division Multiple AccessAccess) Means multiple access (multi-user) ) Means multiple access (multi-user) divided by divided by codecode. Different . Different GSMGSM distribution distribution frequencyfrequency into the small channel, and share into the small channel, and share timetime he channels for he channels for usersusers. While the mobile . While the mobile subscriber share the same CDMA frequency subscriber share the same CDMA frequency common solution. All customers can speak common solution. All customers can speak simultaneously and simultaneously and SignalingSignaling broadcast on broadcast on the same frequency solution. The subscription the same frequency solution. The subscription channels are separated by using random channels are separated by using random code. Signals from many different code. Signals from many different subscription will be subscription will be encodingencoding with different with different random codes, are then mixed and broadcast random codes, are then mixed and broadcast them on the same frequency and only solution them on the same frequency and only solution to recover only in the subscriber equipment to recover only in the subscriber equipment (mobile telephones) with the corresponding (mobile telephones) with the corresponding random code random code

FAC code of some FAC code of some countries countries

YY (FAC)YY (FAC)06 France06 France07, 08, 20 Germany07, 08, 20 Germany10, 70, 91 Finland10, 70, 91 Finland18 Singapore18 Singapore19, 40, 41, 44 UK19, 40, 41, 44 UK30 Korea30 Korea67 USA67 USA71 Malaysia71 Malaysia80, 81 China 80, 81 China

TAC FAC SNR CD

IMEI

Thank you !Thank you !