GSM Foundation Course Prepared by Syed Amir Abbas

GSM Foundation Course Prepared by Syed Amir Abbas ZAC Technical Institute

GSM Operator in Pakistan ZAC Technical Institute

GSM and Others CDMA One TDMA 11% GSM 14% 75% Source: European Mobile Communications(EMC) ZAC Technical Institute

Vendor’s Of Operators Core (MSC/BSC) n n n Mobilink Alcatel/Huawei/Siemens/Nokia Ufone Huawei/Nortel Telenore Siemens/Nokia Warid Ericsson Zong ZTE/Huawei ZAC Technical Institute RAN (BTS) Motrola/Alcatel Huawei / Nortel Siemens / Nokia Ericsson / Huawei Ericsson/ZTE/Alcatel

Subscriber Data Base n n n Mobilink Telenore Ufone Warid Zong 31, 958, 597 17, 841, 074 17, 800, 424 15, 114, 678 3, 662, 099 Information received from PTA site survey on May 2008 (www. pta. com) ZAC Technical Institute

What is Telecommunication ? n Telecommunication means to change information into electronic signals for remote transmission and switching. n Fast Deployment n Saving Transmission cost. n Easy and Fast Access. ZAC Technical Institute

Frequency “ The frequency of a radio wave is the number of times that the wave oscillates per second. " q q q FM Radio : Television : Mobile Networks : ZAC Technical Institute 100 MHz Approx. 300 – 2000 MHz Approx.

Bandwidth n n n In electronic communication, bandwidth is the width of the range (or band) of frequencies that an electronic signal uses on a given transmission medium. In this usage, bandwidth is expressed in terms of the difference between the highest-frequency signal component and the lowest-frequency signal component. Bandwidth = Highest freq – Lowest Freq ZAC Technical Institute

Channels n A Channel is a frequency or set of frequency which can be allocated for the transmission and reception of information. n Types Of Communication Channels. ZAC Technical Institute

What is Multiple Access n Simultaneous private use of a transmission medium by multiple independent users is called Multiple Access. n Advantages Of Multiple Access • • • Increased capacity Reduced capital requirement Decreased per user expense ZAC Technical Institute

FDMA, TDMA & CDMA n FDMA (Frequency Division Multiple Access) n Each user on a different frequency A channel is a frequency n n n TDMA (Time Division Multiple Access) Each user on a different window period in time slot. CDMA (Code Division Multiple Access) Each user uses the same frequency all the time but mixed with different distinguished code patterns. ZAC Technical Institute

st 1 Generation Cellular System n Widespread introduction in early 1980 s. n Analogue modulation. n Frequency division multiple access. n Voice traffic only. n No inter-network roaming possible. n Insecure air interface. n Examples : q AMPS (Advance mobile Phone System, American based, 800 MHz) q TACS (Total Access Communications System, UK based, 900 MHz) q C-450 (German standard, 450 MHz) q JTACS (Japanese Total Access Communications System, 900 MHz). ZAC Technical Institute

2 nd Generation Cellular System n Widespread introduction in 1990 s. n Use digital modulation. n Variety of multiple access strategies. n More efficient use of radio spectrum. n International roaming capability. n Secure air interface. n Compatibility with ISDN. ZAC Technical Institute

GSM Architecture Overview n A GSM system is made up of three subsystems: q q q n The mobile station (MS) The Base station subsystem (BSS) The Network and switching subsystem (NSS) The interfaces defined between each of these sub systems include: q q q “A” interface between NSS and BSS “Abis” interface between BSC and BTS (Within the BSS) “Um” air interface between the BSS and the MS ZAC Technical Institute

Abis Interface ZAC Technical Institute

GSM Frequency Concepts ZAC Technical Institute

GSM Call Setup ZAC Technical Institute

AUC HLR n MS BTS BSC HLR MSC VLR AUC n EIR n SMSC Centre VMS Voice Messaging System Pre. Paid Node Hosting prepaid service system IN Intelligent Network services PSTN Public Switched Telephone Network PABX Private Automatic Branch Exchange n BSC n n n VMS Pre. Paid Node EIR MSC/VLR Warid SMSC n n INTERNET Telenore n n n PSTN ZAC Technical Institute Mobilink MSC w BSC Mobile Station = phone + SIM card Base Transceiver Station Base Station Controller Home Location Register Mobile services Switching Centre Visitor Location Register Authentication Centre Stand-alone or integrated in HLR Equipment Identity Register For blacklisting stolen and unwanted equipment Short Message Service ”Support”

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

BSC Base Station Controller n n ZAC Technical Institute The call request reaches the BSC from the BTS and is forwarded to MSC. After call is established, the BSC will perform decoding of the call (in typical config. )

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n n Checks A number. To whom is A subscriber calling? (Checks B number) Example : A subscriber has prepaid number. MSC Mobile Switching Centre ZAC Technical Institute

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n Does the A subscriber have money left on his/her account? When the call is established and on-going the subscriber’s account is decremented accordingly. Pre. Paid Node ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n Where is the B subscriber? MSC interrogates in HLR. (HLR = Home Location Register) MSC Mobile Switching Centre ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n HLR says ’I am the home of the B subscriber and I know where he/she is right now’ (i. e. which VLR) Tells this VLR ’Give me a visitor address for this subscriber’ (Roaming Number) HLR Home Location Register ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n Hosting MSC/VLR returns TEMPORARILY assigned visitor/roaming address for Bsubscriber to HLR. MSC Mobile Switching Centre ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n ’Thanks for the visitor address!’ ’I will send this address to the MSC that requested for it. ’ HLR Home Location Register ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n ’Thank you, HLR!’ Speech connection path will set up now towards the MSC/VLR where the B subscriber is presently located. MSC Mobile Switching Centre ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n Sets up a speech connection towards BSC. Delivers B-subscriber ID to BSC and asks to page for the subscriber using that ID. MSC Mobile Switching Centre ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC

n n BSC now sends a PAGING MESSAGE to all the BTSs that it covers/controls. Carrys PAGING RESPONSE from called MS back to MSC. Allocates a RADIO channel through a BTS with best available and allowable SIGNAL STRENGTH for called MS. Performs SPEECH CODING when call is established. BSC Base Station Controller ZAC Technical Institute

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network ZAC Technical Institute PSTN PABX International BSC