1. Mobile Communication MMS / GPRS

2. What is GPRS ? General Packet Radio Service (GPRS) is a new bearer service for GSM that greatly improves and simplifies wireless access to packet data networks GPRS applies packet radio principal to transfer user data packets in an efficient way b/w MS & external packet data network

3. Benefits of GPRS New Data Services High Speed (Data Rate 14.4 – 115 kbps) Efficient use of radio bandwidth (Statistical Multiplexing) Circuit switching & Packet Switching can be used in parallel Constant connectivity

4. Comparison of GSM & GPRS GSMGPRS Data Rates9.6 Kbps14.4 to 115.2 Kbps Modulation Technique GMSK BillingDuration of connection Amount of data transferred Type of Connection Circuit – Switched Technology Packet - Switched Technology

5. High Data Rate GPRS uses radio channel i.e. 200 kHz wide Radio channel carries digital data stream of 271 kbps This rate is divided into 8 time slots each carrying 34 kbps per time slot Data rate 14 kbps per time slot achieved after corrections GPRS can combine upto 8 time slots giving data rate of 114 kbps

6. GPRS Terminals Class A –MS supports simultaneous operation of GPRS and GSM services Class B –MS able to register with the n/w for both GPRS & GSM services simultaneously. It can only use one of the two services at a given time. Class C -MS can attach for either GPRS or GSM services

7. GPRS Network Elements GPRS Architecture is same as GSM except few hardware modifications :  GPRS includes GSNs  SGSN : Serving GPRS Support Node  GGSN : Gateway GPRS Support Node  GPRS Register

8. GSM SYSTEM ARCHITECTURE MS BTS PSTN ISDN PDN BSC MSC/VLR MS BTS GMSC EIR AUC HLR

9. GPRS SYSTEM ARCHITECTURE BSC SGSN MS BTS Other GPRS PLMN GGSN PDN Gb Gd Gp Gn Gf Gs Gc GGSN EIR HLR+GPRS Register MSC/VLR D SMS-GMSC SMS-INMSC Gi Gr

10. SGSN – Serving GPRS Support Node Delivers data packets to mobile stations & vice-versa Detect and Register new GPRS MS in its serving area Packet Routing, Transfer & Mobility Management Authentication, Maintaining user profiles Its location register stores location info. & user profiles

11. GGSN – Gateway GPRS Support Node Interfaces GPRS backbone network & external packet data networks Converts the GPRS packets from SGSN to the PDP format Converts PDP addresses change to GSM addresses of the destination user Stores the current SGSN address and profile of the user in its location register Performs authentication Many-to- many relations among SGSNs & GGSNs

12. SESSION MANAGEMENT IN GPRS

13. Attachment & Detachment Procedure GPRS attach -User is registered in SGSN, after authentication check from HLR -SGSN assigns P-TMSI to MS GPRS detach -Disconnection of MS from GPRS network is called GPRS detach -It can be initiated by MS or by network(SGSN or HLR)

14. Session Management Mobile Station applies for PDP address For each session PDP context is created & it contains –PDP type –PDP addressed assigned to MS –Address of GGSN that servers access point to PDN With active PDP context MS able to send or receive data packets Allocation of PDP address can be static or dynamic

15. PDP Context Activation

16. Channels in GPRS Logical Channel –Traffic Channels –Signaling Channels (Control Channels) Physical Channels

17. Logical Channels

18. Packet Data Channel(PDCH) Physical Channel for GPRS Traffic PDCH are taken from all channels available in the cell Depending on current traffic load and priority of service, the physical channel are allocated to either GPRS or GSM services. Physical channels not currently used by GSM can be allocated as PDCH to increase the QOS for GPRS

19. Multiframe Structure of PDCH Four consecutive TDMA frame forms one block - B0 – B11 Two TDMA frames for transmission of PTCCH - T Two Idle frames - X