Mobile Wireless

2 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Exponential Growth of World Wide GSM Data Users Growth in mobile data is expected to be 70% p.a. in next 5 yrs (Merryl Lynch) in million subscriber early adaptorsearly majorityLate majorityinnovators ~ 1%

3 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Dramatic Increase of Mobile Data Volume Mbytes per user per month UMTS study funded by the European Comission data will account for up to 75% of total mobile traffic by 2005 up to 40% of people in the EU will be using mobile phones Today 0.8 Mb/user/month

4 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Wireless Data Network Drivers Information access PDAs Network computers Alpha paging, information distribution Web/WAP technology

5 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Data Applications Call Forwarding37% Paging33% Internet/ 24% Traffic/Weather15% Conference Calling13% News 3% Call Forwarding37% Paging33% Internet/ 24% Traffic/Weather15% Conference Calling13% News 3% Services Most Often Requested Source: CTIA Web Page Peter D. Hart Research Associates, March 1997 After Basic Wireless Telephony Service

6 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Data Services on Cellular Standards for packet services on cellular are already defined GSM: GPRS - GSM Packet Radio System CDMA: IWF and MobileIP Both utilize bandwidth over the backhaul/backbone to gateway devices A data network built for packet data transport can reduce the need to expand the backbone beyond voice requirements

7 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Wireless Market Segments

8 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Residential WLANs Found in office environment for wireless network access Either infrared or radio Standards are Bluetooth IEEE

9 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Fixed Wireless Provide high speed wireless link to connect remote sites Point-to-point or point-to-multipoint Line-of-sight or non-line-of-sight systems Two standards LMDS – Local Multipoint Distribution System MMDS

10 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Mobile Wireless Networks Usually digital cellular radion networks Provide voice and data services 1G – analog transmission 2G – digital cellular networks (like GSM) Circuit switched 2G+ HSCSD (circuit switched bundeled timeslots) GPRS (voice CS, data PS) 3G – like UMTS Completely packet switched voice and data

11 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS and other Mobile Wireless Technologies GSM dataCircuit 9.6 kbits/s Low ETSI Now HSCSDCircuit 56 kbits/s Medium ETSI EDGEPacket 380 kbits/s Medium Ericsson GPRSPacket 150 kbits/s Medium ETSI UMTSPacket 2 Mbits/s High (radio) ETSI 2002 HSCSD…High Speed Circuit Switched Data EDGE … Enhanced Data Rate for GSM Evolution GPRS … General Packet Radio Service UMTS … Universal Mobile Telephone Service Technology Type Throughput Investment Std. Body Availability

12 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GSM Packet Data Service Options Two services as part of "Phase 2+" of the GSM specification High Speed Circuit Switched Data (HSCSD) General Packet Radio Service (GPRS)

13 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel High Speed Circuit Switched Data (HSCSD) allows the combination of multiple timeslots Channels can be multiplexed together to offer a data rate of up to 56 Kbit/s when using all four slots (14.4 Kbs/channel) because each time slot could carry a conventional conversation, the use of multiple slots restricts the capacity for speech traffic, resulting in the handset user specifying a minimum acceptable data rate and a preferred (and usually higher) data rate will prove particularly useful for applications with high- speed data requirements, such as large-scale file transfers, advanced fax services and mobile video communications

14 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel General Packet Radio Service (GPRS) available over GSM networks Data is packet switched - voice remains circuit switched may also be supported as part of other standards, such as DECT and TDMA based on the transportation and routing of packetized data Capacity limitation is hence in terms of the amount of data being transmitted rather than the time of connection reduces the time spent setting up and taking down connections works with public data networks using Internet protocol & X.25 "bursty" applications such as , traffic telematics, telemetry, broadcast services, and Web browsing requires modifications to the GSM system architecture and has targeted commercial availability in the 1999 timeframe

15 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel HSCSD vs GPRS HSCSD is a small market HSCD doesn’t do anything to ease spectrum capacity constraints that operators are facing GPRS benefits ultimately, higher speed data the packet data element is most important because it uses the spectrum in a better way not tying up a whole channel end-to-end for one user

16 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Enhanced Data Rate for GSM Evolution (EDGE) GSM Standard bodies are defining data networking technologies which will build upon GPRS One such technology is Enhanced Data Rate for GSM Evolution (EDGE) EDGE will offer a theroretical rate of up to 384 Kbs. Beyond EDGE, 3G (UMTS) cellular systems will eventually offer data rates up to 2 Mbs

17 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Universal Mobile Telephone Service UMTS 3G mobile system Developed within ITU-2000 framework Frequency bands Terrestrial: 1885 – 2025 MHz and 2110 – 2200 MHz Sattelite: 1980 – 2010 MHz and 2170 – 2200 MHz Data rates up to 2Mbps Inherent IP support Fully packet switched (data and voice) Concept of VME (Virtual Home Environment)

18 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GSM Cellular Packet Data BSC BSC MSC MSC EIR AUC HLR VLR GPRS SGSN and GGSN provide packet data services BTS Backhaul Internet SGSN GGSN Transit Net Transit Net SSS SSS … Switching Subsystem VLR … Visitor Location Register HLR … Home Location Register AUC … Authentication Center EIR … Equipment Identity Center MSC … Mobile Switching Center BSS BSS … Base Station Subsystem BSC … Base Station Controller BTS … Base Transceiver Stations GSN … GPRS Support Node SGSN … Serving GSN GGSN … Gateway GSN

19 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GSM Network Areas

20 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GSM Network Areas GSM network consists of geographical areas Location Areas – LA made up of a group of cells served by a BSC BSC hndles inter cell signaling updates Keeps track of the cell a user is located MSC/VLR Service Areas MSC administers several BSCs handles signaling traffic of inter LA updates Public Land Mobile Networks – PLMNs

21 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS Logical Architecture PS GPRS uses completely different network architecture as underlying GSM network Thus introduction of two new network nodes GPRS Support Nodes SGSN … Serving GSN (GPRS Support Node) GGSN … Gateway GSN (GPRS Support Node)

22 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel SGSN and GGSN Functionality SGSN Keeps track of user’s location Performs security functions and access control GGSN Provides internetworking functions with external networks Simply a strong router with IP and X.25 capability

23 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Further Elements and Enhancements SGSNs are connected to PCUs (Packet Control Units which are part of the BSC) Via Gb interface – with FR links GSNs are interconnected over Gn interface via IP backbone GPRS backbone or GPRS network HLR is enhanced with GPRS subscriber information SMS components are upgraded to support SMS transmission via SGSN

24 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Intra and Inter PLMN Backbone Networks Gp interface Connects two independent GPRS networks for message exchange Message exchange done by BG (router) Gi interface Connection between operator’s GPRS networks and external networks (Internet)

25 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS Support Nodes GSN is main element in GPRS infrastructure Mobility router Provides connection Enables interworking with various data networks

26 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GGSN Used to access external data network IP router containing all necessary routing info for attached GPRS users Routing info used to tunnel PDUs to MS’s current point of attachement (SGSN) Allocation of dynamic IP addresses Either itself or external DHCP server

27 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel SGSN Serves MS in terms of packet data services SGSN establishes connection via GGSN to requested data network Maintains all data structures (contexts) for Authentication Routing process In case of roaming (SGSN and GGSN in different PLMNs) – interconnected via Gp interface Provides security and others

28 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel PCU Located in the BSC Acts as an interface to the SGSN Distinguishes data and voice Sends data over FR via SGSN into GPRS backbone Realized in SW or HW

29 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel APN Access Point Name Defined by ETSI in order to deal with huge number of IP networks to connect to Uniquely identifies the network a user wants to access L3 protocols defined are IPv4 and IPv6

30 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Access Point Name (username) Type (Ipv4, Ipv6, X.25) Access mode (non/transparent) DHCP local pool information Accept network initiate PDP create request List of PDP contexts on the APN IP for DHCP, RADIUS … IP for charging gateway APN Contains Name of foreign NW Network access mode Stored in HLR User may select APN by himself from the MS

31 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS Concepts APN: targeted network (ISP, intranet) PDP context: session id 1) reach the SGSN (telecom part) 2) reach the GGSN serving the APN (GTP=moving tunnel) 3) reach the APN (dedicated link, tunnel)

32 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS PDN Interworking Model GGSN is access point for internetworking Seen from outside as normal router GPRS network seems to be normal IP subnet

33 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GPRS Transmission Plane Um … radio interface Uses same PL coding as classical GSM Thus no HW changes TE requires up to 8 slots / TDMA frame GTP … GPRS Tunneling Protocol SNDCP … Subnetwork Dependent Convergence Protocol BSSGP … Base Station System GPRS Protocol

34 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Gb Interface Link layer is FR BSSGP (BSS GPRS) conveys routing and QoS info between BSS and SGSN SNDCP encapsulates IP traffic between terminal and SGSN Multiplexing of L3 connections Ciphering, segmentation, compression

35 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Gn Interface GTP (ETSI) tunnels IP packets between SGSN and GGSN One tunnel per active TE Runs either over UDP or TCP

36 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel MS MS could be Only GPRS phone User with NW connection via GPRS to his PC

37 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Transparent Internet Access User who wants to get connected to internet MS is given an IP address out of the operators address space Could be statically or dynamically allocated May be public or private Authentication performed by SGSN via HLR The GGSN is effectively a router The GPRS network appears to the PDN as another IP subnet

38 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Transparent Internet Access

39 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Non Transparent Access Allows user to select SPs of his choice Connection to intranet VPN for access, intraweb, databases Has to request IP address and perform authentication in company network Realized by SGSN during PDP context activation via selected APN MS sends authentication request GGSN requests authentication and IP address from specified server (Radius, DHCP) of customers intranet Use of Ipsec and/or L2 tunnel for terminating private IP addresses at GGSN via Internet

40 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Interworking Between GPRS Roaming User’s BGP (RFC 1771)

41 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel QoS on GPRS BSC SGSNGGSN FR TransitNet IP BTS PSTN H.323GW H.323 client IP QoS CRTP FR CoS Priotities IP QoS CAR WFQ CRTP IP QoS WFQ WRED IP QoS H.323 Gateway

42 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Quality of Service Mapping between GPRS QoS and IP QoS levels Use of IP CoS mechanisms in GGSN/SGSN and in the Backbone: WRED, WFQ, CAR Admission Control (GGSN):  traffic  Total BW

43 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Backbone Issues Leverage End-to-End Consistency WFQ, WRED, CAR MPLS (GGSN as edge router) Integrated management

44 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel IP Address Management GGSN can hold (local pool/DHCP): – Operator’s public IP addresses – Operator’s private IP addresses (NAT) – Other’s public IP addresses (local pool) – Other’s private IP addresses (local pool, dedicated I/F) configuration per APN

45 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel IP Address Management GGSN can allocate addresses: – transparently (local pool using built-in DHCP server/DHCP) – non-transparently (CHAP/IPCP processing, RADIUS/DHCP requests generation) through IOS built-in RADIUS/DHCP clients configuration per APN

46 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel GSM to UMTS Evolution

47 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel Evolution Towards UMTS UMTS Backward compatibility to legacy systems Operators will try to use existing infrastructure as long as possible Development steps 1) MIP on top of GPRS 2) optimize existing routing mechanisms 3) SGSN and GGSN combined in one node In future UMTS will completely integrate PSTN VSCs will replace all class 4 and class 5 switches Calls will be routed over IP backbone

Questions ???