4GPRS BACK GROUNDWith Mobile penetration reaching its full potential, GPRS gives Mobile operators competitive edge and optimum use of the infrastructure.SMS is a good example of just how hungry users are for data services.The main Objective of GPRS is to offer the access to standard data networks, using protocols e.g. TCP/IP and X.25Transactions such as Credit Card checks and a variety of telemetric applications benefit from the fast session set-ups.GPRS enables efficient use of radio resources by allowing many data users to share the same interface on a statistical basis.The main benefits of GPRS are that it reserves radio resources only when there is data to be sentMobile users doesn’t have to connect to the network each time he wants to transfer the data, he can stay connected all day.
5Evolution from GSM to 3G The GSM Growth Phases 3G EDGE GPRS 2.5G HSCSD
6GSM Evolution 2G 2.5G 3G GSM GPRS EDGE UMTS UMTS 5 MHz carrier 2 Mbps peak data ratesNew IMT GHz spectrumGSM200 KHz carrier8 full-rate time slots16 half-rate time slotsGPRS200 KHz carrier115 Kbps peak data ratesEDGE200 KHz carrierData rates up to 384 Kbps8-PSK modulationHigher symbol rateHSCSDHSCSDCircuit-switched data64 Kbps peak data rates
7MAIN ADVANTAGES FOR OPERATORS More Revenue :By providing more than a mobile connection.Also operator can charge on the basis of type and amount of content accessed.Huge Potential Market for Data Sevices :Mobile Phone and Internet, both are fastest growing technologies and GPRS is the merger of two.Fast Roll-out and Continuous Network Expansion :GPRS is an integral part of GSM.GPRS uses excess voice capacity for data :GPRS Packets are transmitted in short, free periods between busy hour calls.
8Free GSM Capacity GPRS packets can be transmitted in 2468101214161:00 PM1:15 PM1:30 PM1:45 PMTCH03:0006:0009:0012:0015:0018:0021:0000:00TCHGPRS packets can be transmitted inthe short free periods between busyhour calls2TRX = 14 Speech TS2% blocking means8 Erlang speech trafficØOn average 6 TS free !
9GPRS Vs GSM GPRS Vs GSM 1. SUPPORTS BOTH CKT. Only circuit switched. SWITCHED as well aspacket switched service.2. MS Utilizes Automatic No re-transmission isretransmission (ARQ) at provided.data link layer to re-transmiterror frames.3. Multiple time slots can be Single time slot per user.allotted to a single user4. One time slot can be allotted Single time slot per user.to several users.5. Charging/ billing more complex Simple time-based billing.(Volume based, Q.O.S. based)
10TYPICAL GPRS SERVICES * Communications- E-mail, fax, intranet/ internet access.* Value added services Information services, games,e-commerce.* Location-based applications - Navigation, traffic conditions,airline/rail schedule, location finder.* Vertical applications Freight delivery, fleet management,sales-force automation* Location sensitive A user nearing a cinema hall orAdvertising a restaurant receives flashes ofadvertisement
12The Main elements of GSM are: GSM NETWORK ELEMENTSThe Main elements of GSM are:NSS :MSCVLRHLR (Includes Authentication Center and Equipment Identity Register)BSS :BSCBTSTranscoderNMSFault ManagementConfiguration ManagementPerformance Management
13GPRS Network Elements Network Element Software Hardware SGSN SG1 DX PlatformGGSN G1 IP650Firewall Checkpoint IP650Ethernet Switch N/A Cisco CatalystDNS HP-UX HP 9000 A classCG HP-UX HP K classBorder Gateway BGP IP650DHCP HP-UX HP 9000 A class
16SGSN Role Authentication, Authorization GTP tunneling to GGSN Ciphering & compressionMobility ManagementSession ManagementInteraction with HLR, MSC/VLRCharging & statisticsNMS interfaces
17GGSN Role Interface to external data networks Encapsulate in GTP and forwards end user data to right SGSNRoutes mobile originated packets to right destinationFilters end user trafficCollects charging and statistic information for data network usage
21MS ClassCLASS A: Supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation, and simultaneous traffic.CLASS B: Simultaneous traffic shall is not supported. The mobile user can make and/or receive calls on either of the two services sequentially but not simultaneously. The selection of the appropriate service is performed automaticallyCLASS C: Supports only non-simultaneous attach. Alternate use only.The status of the service which has not been selected is detached, that is, not reachable.
22GPRS Channel Coding Schemes GPRS can also increase the data rate in a single timeslot. The coding schemes listed above are based on the current scheme used for GSM signaling channels (notice a single slot rate of 9.05 in CS1 as opposed to the TCH data rate of 9.6 in GSM).To increase the data rate, some of the error detection and correction bits are removed from the burst. So CS2 has less C&D bits than CS1, and CS4 has no error protection at all. The consequences of this are that to maintain a call in CS4 it is necessary to have excellent signal quality. This can only be achieved at positions closer to the BTS. Therefore, the cell radius is greatly reduced when using CS3 and CS4.The BSS automatically upgrades and downgrades the connection among the coding schemes based on the number of erroneous packets it receives.In the first release of GPRS, only CS1 and CS2 are implemented. This is because CS3 and CS4 require structural changes to the Abis interface. These data rates will not fit into a 16kbit/s channel.
24Mobility Management State GPRSAttach/ DetachIdleReadyREADYTimer ExpiryPacketStandbySTANDBYTX/RXTimer ExpiryMS location known toMS location known tocell level.MS locationSGSN level.MS is transmitting or hasnot known.MS is capable of receivingjust been transmitting.Subscriber is notPoint-to-Multipoint dataMS is capable of receivingreachable by theand being paged forPoint-to-Point data andGPRS NW.Point-to-Point dataPoint-to-Multipoint data.
26GPRS Mobility Management Routing Area :The RA is a new concept for tracing the MS location.Cell =< RA =< LA served by one SGSNRAI = MCC + MNC + LAC + RACEvery time the MS sees the new RAI is has to initiate the RAupdate procedure.
27GPRS Mobility Management Mobility Management States :The IDLE State is when the MS is not connected.The Standby State is when the MS is connected to the GPRS NetworkThe Ready State is when the MS is ready to connect to the external IP Network.Changing between states can be initiated from the MS, from the network and from the timers set.
29PDP Context Activation Accessing the HLR (1) MS sends "Activate PDP Context Request" to SGSNAccess Point NamePDP Type (IP)PDP Address (empty == dynamic)HLR2.BTSBSCSS71.(2) SGSN checks against HLRAccess Point NameDynamic / static IP addressAPN="Intranet.Ltd.com"SGSNDNSGPRSBackboneIP NetworkAccessPointIntranetGGSNInternetAccess Point Name = Reference to an external packet data network the user wants to connect to
30ADDITIONAL GPRS SECURITY FEATURES ARE SECURITY IN GPRSGPRS SYSTEM HAS INHERITED THE GSM PH-2 SECURITY FUNCTIONSAuthentication of the subscriberIMEI CheckingUser Identity Confidentiality (TMSI in GSM, P-TMSI in GPRS)Ciphering of the data traffic between MS and SGSNPrivate IP Addressing in the GPRS backbone.Ciphered links and authentication between nodes in the GPRS Backbone.Screening of packets coming from the external networks (Firewall).(P-TMSI is used to derive the Temp Logical Link Identity (TLLI))ADDITIONAL GPRS SECURITY FEATURES ARE
31EGPRS = GPRS + EDGE modulation The AbbreviationGPRS = General Packet Radio SystemEGPRS = GPRS + EDGE modulation
32EDGE – Provide 3G services today Provide 3G services with existing licensesNew modulation optimized for wireless data servicesLink adaptation: Take highest possible rateCovered by existing GSM licensesSame channel structure, network infrastructure, frequencyplanning and protocol as today’s GSM
33Evolution to EDGE SMS G/IW MSC HLR AUC BTS BSC MSC/VLR EDGE TRU SGSN GdAUCMSBTSPUCBSCMSC/VLRGrISP NetworkGsGbEDGE TRUMSGiSGSNGGSNGnGnCorporateNetworkBackbone Network