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gprs-edge

  1. 1. EPFLCours “Mobile Networks” GPRS & EDGE « First steps toward Wireless data » Frédéric Michaud Network Development Engineering 14/12/2004
  2. 2. GPRS Part 1 Content From Theory… From Theory… 11- -INTRODUCTION INTRODUCTION 22- -SERVICES SERVICES 33- -ARCHITECTURE ARCHITECTURE 44- -MOBILITY MANAGEMENT MOBILITY MANAGEMENT 55- -SESSION MANAGEMENT SESSION MANAGEMENT 66- -TRANSMISSION ON BSS NETWORK TRANSMISSION ON BSS NETWORK 77- -RADIO RESOURCE MANAGEMENT RADIO RESOURCE MANAGEMENTFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 2
  3. 3. Introduction General Packet Radio Service: a way to extend packet transfer up to the mobile station GSM GSM GPRS GPRS – Circuit Switch –– Packet Switch architecture Packet Switch architecture – Circuit Switch architecture architecture –– End to End IP service (mobile End to End IP service (mobile – Indirect access to IP = IP host) = IP host) – Indirect access to IP network network –– Re-use BSS architecture Re-use BSS architecture – Too sensitive – Too sensitive –– New core architecture New core architecture connection for data connection for data –– Max theoretical rates ~170 Max theoretical rates ~170 (today) (today) kbps kbps – Expensive solution for – Expensive solution for data network (HSCSD) data network (HSCSD)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 3
  4. 4. Services BANKING & FINAN- LOCAL SERVICES Special NEWS BUY & SELL TRAVEL CIAL SERVICES (CITY GUIDE) Interest General Headlines Stock indexes Taxi Classifieds Traffic (traffic jams, Mobile telephones Financial & Business Stock prices Restaurants - Cars radar, control,…) Internet sites and Politics Metal prices Cinema - Properties Public transportation services Tabloids Stock alert Theatres - Jobs Navigation services Computers and Culture & Currency rates Concerts Auctions Train schedules hardware Entertainment Interest rates Exhibitions Shopping Flight schedules Automobile INFOR- Sports Account balance Night Clubs - Small daily Hotels Lottery Credit/debit balance Emergency services items Holiday packages MATION Cheque balance Pharmacies - Specific Money transfers Household promotions Bill payments assistance Tickets Automatic call Weather Account status flash Time Stock purchase Directory services Financial products ATM Locator purchase SMS E-MAIL FAX BULLETIN BOARDS COMMU- Groups with common Send/receive SMS messages Send/receive e-mails Send/receive fax NICATION SMS to postcard E-mail to voice (IVR) Special features (delivery and receipt interest report, storage for later delivery) Messages, News, etc ORGANIZERS PERSONAL ASSISTANT TOOLS MISCELLANEOUS FAMILY PRODUC- To do lists Reminders Call management Calculator Activating domestic Family VPN TIVITY Calendar Correspondence management Dictionary appliances Synchronised Address book Voice to SMS, E-mail and fax Translator Paying at vending machines Agenda Translation services Currency converter Identity verification ASTROLO- MUSIC TV LIFESTYLE FUN CHATS PICTURES GAMES DATING GY ENTER- Ringtones Program- Gastronomy Jokes Topic Icons Puzzles Horoscopes Chats TAINTMENT Short clips me Hobbies Sayings specific Logos Quizzes Astrolove Dating (e.g. MP3) schedules Fashion Dream Private Photos “Tamagotchi” Biorhythm services Highlights Parties analysis Postcards Games Specific Gambling/Betting HoroscopesFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 4
  5. 5. Services Notion of QoS QoS = Quality of Service 5 Classes as specified in ETSI – Service Precedence / Priority – Delay – Mean Throughput – Peak Througput – Reliability FTP (NRT): Video Streaming (RT): – Service: minor – Service: medium – Delay: < 7 sec (most likely Best effort) – Delay: < 7 sec (most likely Best effort) – Mean throughput: 4.4 kbps – Mean throughput: 44 kbps – Peak throughput: N/A – Peak throughput: 64 kbps – Reliability: high to medium redundancy – Reliability: medium to low (UDP protocol)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 5
  6. 6. Architecture Network Diagram NSS ISP - External HLR GPRS Core Network Network MSC/VLR Gc Gr Gi Gs SGSN DNS GGSN A Gn Gn BSS GPRS Gb IP Backbone GnTranscoder Gn Ater Charging Border Gateway Gateway Um Gp BSC Abis Inter PLMN Backbone BTS Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 6
  7. 7. Architecture New interfaces Interface elements Main usage Protocol type Um MS – BTS Radio interface RLC/MAC Abis BTS – BSC Standard GSM if. RLC/MAC Gb BSC – SGSN GPRS data LLC/FR Gc GGSN – HLR HLR queries for PDP context (IP)/SS7 activation Gd SGSN – SMS GMSC Short Messages exchange SS7 Gf SGSN – EIR Terminal identity check SS7 Gi GGSN – Data Network Data transfer IP Gn SGSN – SGSN Mobility management IP SGSN - GGSN PDP context activation Data transfer Gp BG – BG Inter-operator link IP Gr SGSN – HLR Location management SS7 Gs SGSN – MSC/VLR GSM/GPRS mobility Management SS7Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 7
  8. 8. Architecture evolution of BSS network New hardware in BSS: Packet Controlling Unit (PCU) – can be compared to TRAU function in GSM – generally located in the BSC – heart of the packet transmission in BSS network – allow the dynamic traffic allocation – Provide the radio resource management mechanism, adapted to packet BTS transfer RLC RLC RLC PCU SGSN buffer RLC RLC RLC LLC LLC LLC buffer RLC Gb RLC buffer RLC AbisFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 8
  9. 9. Architecture New core equipments HLR VLR Charging Gateway External PCU External IP world IP world GGSN PCU IP network SGSN GGSN • Packet routing (IP – BSS) • Mobility Management • GPRS Tunneling (PLMN – internet) • Session Management • Charging • Charging • O&M (Operation & Maintenance) • Cyphering and compression • Lawful interception Other equipment: Border Gateway, Charging Gateway, DNS, FirewallsFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 9
  10. 10. Architecture GPRS Protocol stacks BSS elements manage everything related to radio resource, mobility and session management Um Gb Gn Gi Applica Data traffic tion IP / IP / X.25 X.25 GMM/SM Relay Mobility Management SNDCP SNDCP GTP GTP Session Management cyphering UDP / UDP / LLC Relay LLC TCP TCP RLC RLC BSSGP BSSGP IP IP Network Network L2 L2 MAC MAC Service ServiceRadio Resource Management GSM RF GSM RF L1bis L1bis L1 L1(TBF allocation, user/timeslot multiplexing, etc..) MS BSS SGSN GGSN PS/CS paging Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 10
  11. 11. Architecture Gb interface Open interface between the BSC and the SGSN. Consist of three layers: – Frame Relay: link layer access between peer entities via a Bearer Channel. – Network Service: set of virtual connections responsible for data transmission, congestion control, load sharing between Network Service Entities. – BSSGP: Virtual Connection management, paging support, flow control support. NS-VC DLCI Data Link Connection Identifier (FR BVC 0 address) NS-VC BVC 0 for for signalling FR Bearer Channel signalling NSE Physical Link (= pcm-tsl) NSE (=PCU ) Own BVC Own BVC for for each BTS each BTS NS-VC DLCI Data Link Connection Identifier (FR NS-VC address) Load Sharing FR Bearer Channel Physical Link (= pcm-tsl) BSC SGSN BVC = BSSGP Virtual Connection BSSGP = Base Station Subsystem GPRS Protocol NSE = Network Service Entity NS-VC = Network Service Virtual Connection FR = Frame Relay Gb interface will move on IP protocolFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 11
  12. 12. Mobile equipment Three types of Mobile Classes CLASS A: « Rolls Royce » CS Core Network (GSM) Simultaneous CS/PS Paging Simultaneous CS/PS data transfer PS Core Network (GPRS) CLASS B: « Standard » CS Core Network (GSM) Simultaneous CS/PS Paging CS call or PS data transfer PS Core Network (GPRS) CLASS C: « Cheap » CS Core Network (GSM) CS mode (GSM only) or PS mode (GPRS only) PS Core Network (GPRS)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 12
  13. 13. Mobility Management Mobile States IDLE – not attached to GPRS – MS is not reachable IDLE GPRS Attach GPRS Detach READY – MS known down to Cell by SGSN STANBY timer READY – May receive/transmit packets expiry – No Packet paging required READY timer expiry PDU Transmission – MS remains in READY state until “READY Force to STANBY Timer” expires or GPRS Detach STANDBY STANDBY – MS known down to Routing Area by SGSN – MS attached to GPRS – May receive Packet paging – No data reception or transmissionFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 13
  14. 14. Mobility Management Temporary identity Notion of P-TMSI (Packet Temporary Mobile Subs Identifier) – Temporary identifier to differentiate a mobile in a SGSN – associated to a ciphered signature – P-TMSI+ signature transferred at each location update Notion of TLLI (Temporary Logical Link Identifier) used between MS and SGSN before attachment randomly selected by MS when uplink request (risk of collision) after attach : TLLI=P-TMSI used to identify MS on the air interface IMSI is never transferredFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 14
  15. 15. Mobility Management Paging enhancement with GPRS Network Mode I Network Mode II HLR HLR MSC/VLR Gr MSC/VLR Gr SGSN SGSN Location update Gs CS paging or SMS A Gb A Gb CS paging or SMS BSC BSC Paging message on: Paging message on: Abis Paging channel Abis Paging channel only Packet data channelFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 15
  16. 16. Mobility Management GPRS Attach SMSC BSC MSC/VLR HLR 3 2 4 5 DNS 1 Charging 2 SGSN Gateway 6 GPRS handset 7 GPRS 1. GPRS Attach Request IP Backbone 2. Authentication Border GGSN Gateway 3. Update Location (GPRS) 4. Insert Subscriber Data 5. Location Update (GSM) Inter PLMN Backbone ISP External Network 6. GPRS Attach Accept 7. Attach completeFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 16
  17. 17. Mobility Management Routing Area Update DNS BSC SGSN1 GPRS handset GPRS 5 4 3 2 IP Backbone BSC SGSN2 GGSN GPRS handset 1 6 8 7 1. RA Update Request (old RAI) 2. DNS Query: IP @ for old RAI 3. SGSN Context Request 4. SGSN Context Response 5. Forward Packets 6. Update PDP Context Request: IP @ of new RAI 7. Update PDP Context Response 8. RA Update AcceptFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 17
  18. 18. Session Management Notion of PDP context Packet Data Protocol context: – set of information stored in mobile, SGSN and GGSN – allow packet data transfer between a certain type of network and the mobile PDP context contains: Main Field Description type of PDP network IP, X25 …. Mobile address IP address or X.121 address for X25 network SGSN address IP address of the serving SGSN NSAPI Network Service Access Point QoS Profile Quality of service negociated for this PDP context Access Point Name APN (service) requested by the mobile (ie WAP, internet…)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 18
  19. 19. Session Management PDP Context Activation SMSC BSC MSC/VLR HLR 2 DNS 1 Charging SGSN Gateway 5 GPRS handset GPRS IP Backbone 3 1. Activate PDP Context Req Border GGSN Gateway 4 2. DNS Query 3. Create PDP Context Req 4. Create PDP Context Rsp Inter PLMN Backbone ISP External Network 5. Activate PDP Context AckFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 19
  20. 20. Session Management Data Transfer SMSC BSC MSC/VLR HLR DNS Charging SNDCP IP SGSN Gateway GPRS handset IP GPRS S-CDR G-CDR IP Backbone Border GGSN Gateway GTP IP IP IP@ src IP@ dst Inter PLMN Backbone ISP External Network Mobile Server SGSN GGSNFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 20
  21. 21. Radio Resource Management RLC/MAC layer RLC/MAC is the most important layer for communication between MS and BSC: – RLC/MAC controls the data flow over the air interface and Abis interface. – BSS performance are based on RLC block transmissions / retransmission – RLC: Provide controlling function (ack/unack mode) – MAC: Medium Access mode: allows to have dynamic allocation of Mobiles over radio timeslots (pair ofInformation field LLC frame FH TBF/USF) FCS LLC layer RLC BH Info field BCS BH Info field BCS BH Info field BCS blocks Primary Following RLC/MAC layer block block Normal burst Normal burst Normal burst Normal burst Physical layer FH = Frame Header FCS = Frame Check Sequence BH = Block Header BCS= Block Check Sequence (When SDCCH coding is used, BCS corresponds to the Fire code)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 21
  22. 22. Radio Resource Management Notion of GPRS territory GSM TRX 1 CCCH TCH TCH TCH TCH Territory GPRS TRX 2 TCH Territory Default Dedicated GPRS GPRS Capacity Capacity Territory border move based On GSM and GPRS traffic load evolutionFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 22
  23. 23. Radio Resource Management Physical Layer TDMA frame=4,615 ms 01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7 1 GPRS multiframe = 52 TDMA frame=240 ms Block 0 Block 1 Block 2 T Block 3 Block 4 Block 5 i Block 6 Block 7 Block 8 i Block 9 Block 10 Block 11 i 0 4 8 13 17 21 26 30 34 39 43 47 51 12 blocks of 4 radio burst each Each block can transfer one GPRS logical channel informationFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 23
  24. 24. Radio Resource Management Logical Signalling for GPRS GPRS Air Interface Logical Channels CCH DCH Common Channels Dedicated Channels PCCCH BCH Packet Common Control Broadcast Channels Channels DOWNLINK ONLY (can be combined with CCCH) PBCCH Packet Broadcast Control CH (can be combined with BCCH) MS CONTINUOUSLY MONITORS PPCH PAGCH PRACH Packet Paging CH Packet Access Grant CH Packet Random Access CH GPRS: DCH BSS WANTS TO PDCH IS MS ASKS FOR Dedicated Channels CONTACT MS ALLOCATED TO MS PDCHs. DCCH Dedicated Control TCH Channels Traffic Channels PTCCH Packet Timing Control Channel. PACCH Packet Associated Control CH PDTCH Allocated to the opposite direction than the PDTCH Packet Data TCH, one channel can be shared to which it is associated. by several active users.Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 24
  25. 25. Radio Resource Management Timeslot sharing GPRS data transfer = discontinuous series of Temporary Block Flows. – 1 TBF = 1 user (with a given TFI, TLLI, USF) – 1 TBF can be transferred onto several radio timeslots TBF4 TBF3 TBF2 TBF2 TBF3 TBF1 TBF1 TBF1 TSL 0 TSL 1 TSL 2 TSL 3 TSL 4 TSL 5 TSL 6 TSL 7 BCCH TCH TCH TCH PDCH PDCH PDCH PDCH TDMA frame Data transfer = Uplink / Downlink TBF (Temporary Block Flow) Assignment – Timeslots allocation GSM CCCH channels (RACH - AGCH - PCH) (GPRS - phase 1) – GPRS phase 2: dedicated common control channels (PBCCH/PCCCH)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 25
  26. 26. Radio Resource Management Notion of Data flow RLC layer create a Temporary Block Flow, each time data needs to be sent Downlink TFI=14 TFI=14 TFI=14 TFI=14 TFI=14 TFI=14 TFI=14Data transfer BSN=24 BSN=25 BSN=26 BSN=27 BSN=28 BSN=24 BSN=26RLC header Block 0 Block 1 Block 2 T Block 3 Block 4 Block 5 i Block 6 Block 7 Block 8 i Block 9 Block 10 Block 11 i 0 4 8 13 17 21 26 30 34 39 43 47 51 TFI=14 TFI=14 Ack: Ack: 25,27,28 24,26 Uplink Nack: MS receive on 24,26 TFI 14 TBF dynamically managed by the network To avoid collisions, network identify each user with TFI and TLLI Number of retransmission linked to C/I ratio Retransmissions will decrease real user data throughput Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 26
  27. 27. Radio Resource Management Multi user radio sharing MAC layer handle resource sharing between mobiles Downlink SP=0 SP=0 SP=1 SP=1 SP=1 SP=1 TFI=14Data transfer RRBP= RRBP= RRBP= RRBP= RRBP=MAC header i+4 i+3 i+2 i+2 i+1 Block 0 Block 1 Block 2 T Block 3 Block 4 Block 5 i Block 6 Block 7 Block 8 i Block 9 Block 10 Block 11 i 0 4 8 13 17 21 26 30 34 39 43 47 51 TFI=14 TFI=14 Ack: Ack: 25,27,28 24,26 MS receive Nack: on TFI 14 24,26 Mobile knows on which block to ack/nack received PDU Mobile use these control blocks to transfer other information (measurement reports, uplink resource request, etc…) Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 27
  28. 28. Radio Resource Management Dynamic uplink sharing Several mobiles can share the same radio timeslot MAC layer indicates each mobile which block it can use for uplink transfer DownlinkData transfer USF=4 USF=4 USF=1 USF=5 USF=5 USF=4 USF=1 USF=1 USF=5MAC header Block 0 Block 1 Block 2 T Block 3 Block 4 Block 5 i Block 6 Block 7 Block 8 i Block 9 Block 10 Block 11 i 0 4 8 13 17 21 26 30 34 39 43 47 51 Block 3 Block 7 Block 8 MS USF 1 Block 1 Block 2 Block 6 MS USF 4 Block 4 Block 5 Block 9 MS USF 5 Uplink State Flag definition only local to a physical channel (i.e. 1 radio timeslot in the TDMA frame) Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 28
  29. 29. GPRS Part 2 Content … to practice … to practice IMPLEMENTATION CONSTRAINTS IMPLEMENTATION CONSTRAINTS NETWORK DIMENSIONING & PLANNING NETWORK DIMENSIONING & PLANNING NETWORK PERFORMANCE NETWORK PERFORMANCE ANALYSIS AND OPTIMISATION ANALYSIS AND OPTIMISATION TOOLS FOR GPRS TOOLS FOR GPRSFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 29
  30. 30. Implementation Constraints Upgrade of GSM network New Core Network – GPRS backbone is an IP network – New approach in Mobile Telecommunication – First interaction between IT and mobile telecom network dept. Multi-supplier solution – Interoperability problems – Interface Gb, Gs, Gr are standardised by ETSI but multi-vendor solution always leads to complexity. – Mobile and network compatibility over the air interface is another source of problems – Different mobiles = different performancesFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 30
  31. 31. Implementation Constraints Hardware & Software Releases HW & SW Release management – Network is often heterogeneous – Different generation of base stations, BSC and MSC – Software Releases are delivered at different times Incomplete GPRS features – QoS not fully implemented – Radio enhancement (PBCCH) not fully implemented immature ETSI specifications – Suppliers follow different versionsFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 31
  32. 32. Implementation Constraints Heterogeneous BSS Network GPRS Core Network South region - BSS Network North region - BSS Network Supplier A Supplier B GPRS handset GPRS handset Problem of uniform Quality of Service (different SW/HW, different problems) Complex network evolution (i.e. new feature cannot be implemented country wide)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 32
  33. 33. Implementation Constraints Handsets & Services Limitation in mutlislot & coding scheme capability: – First handsets: 2+1 (i.e. 2 TSL DL / 1 TSL UL) 24 kbps DL / 12 kbps UL – Current handsets: 4+1 48 kbps DL / 12 kbps UL ETSI specifications problems – Lots of change request – PBCCH not supported by network and first GPRS mobiles Poor content for GPRS Services – Lack of «adapted» phones – Lack of «killer» applicationsFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 33
  34. 34. GPRS Dimensioning Number of GPRS users Paquet transfer per users Quality of Service Coverage area Network Radio Peak hours Dimensioning Dimensioning Transmission capacity GPRS Territory size (Abis/Gb) Number of cells Bearer size TRX upgrade Number of PCU Signalling increase New hardware requirements New hardware requirementsFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 34
  35. 35. Network Planning Reuse existing GSM coverage Reuse of GSM signalling and traffic plan New core network planning New Routing Area PlanningFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 35
  36. 36. Network Performance Radio constraints Cell reselections – GPRS phase 1: – Network doesn’t control cell re-selection process – Based on GSM cell re-selection of MS in idle mode Risk of ping-pong effect Critical decrease of user data throughput C/I (carrier/interference) criteria – GPRS is very sensible to interferences Data throughput drops quickly with interferences Capacity – GSM traffic has priority over GPRS – « Best effort » mode Low throughput in peak hoursFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 36
  37. 37. Analysis and optimisation Performance Analysis – Access to Network resource 1123 32.15% 298 81.88% 57.26%Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 37
  38. 38. Analysis and optimisation Performance Analysis – Session success 13% 2446 45.4% 623 87% 53.3%Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 38
  39. 39. Analysis and optimisation Tools for GPRS Protocol analyser » In depth signalling studyFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 39
  40. 40. Analysis and optimisation Tools for GPRS Probe System » Data capture across all GPRS network interfaces MSC VLR HLR Gr Gs Gc Gi internet internet Gb Gn BTS BSC SGSN GGSN Gp Foreign Foreign BG PLNM PLNM 1. Data capture 2. Data data storage 3. Data analysisFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 40
  41. 41. Analysis and optimisation Benefit of Gb analysis Full network supervision Access to QoS information Information that can be shared accross mainy actors: – Radio optimisation team – Maintenance team – Quality team – Traffic team High level of detail – Info per session – Info per user – Info per cell/PCU – Info per network areaFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 41
  42. 42. Documentation Réseaux GSM (ISBN 2-7462-0153-4) Xavier Lagrange, Philippe Godlewski, Sami Tabbane Ingénierie des réseaux cellulaires (ISBN 2-7462-0550-5) Sami Tabbane The GSM Evolution - Mobile Packet Data Services (ISBN 0-470-84855-3) Peter Stuckmann GPRS Signalling & Protocol Analysis – Vol. 1 Gunnar HeineFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 42
  43. 43. Evolution towards EDGE Content DEFINITION DEFINITION NETWORK PERFORMANCE NETWORK PERFORMANCE EDGE IMPLEMENTATION EDGE IMPLEMENTATION EDGE DIMENSIONING EDGE DIMENSIONING APPLICATIONS FOR EDGE APPLICATIONS FOR EDGEFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 43
  44. 44. EDGE – evolution of GSM air interface 8PSK modulation to replace GMSK (0,0,0) (0,1,0) (0,1,1) (0,0,1) (1,1,1) (1,0,1) (1,1,0) (1,0,0) EDGE GSM Modulation 8-PSK, 3bit/sym GMSK, 1 bit/sym Symbol rate 270.833 ksps 270.833 ksps Payload/burst 346 bits 114 bits Gross rate/time slot 69.2 kbps 22.8 kbpsFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 44
  45. 45. From GSM to GERAN evolution of specifications 2G 2.5G 2.75G 3G 3GPP (GERAN) GSM GPRS EDGE GERAN ETSI (BSS) UMTS/UTRAN 3GPP (UTRAN)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 45
  46. 46. EDGE as a GERAN feature Enhanced Data rates for Global Evolution, from Release 99 Technical aspects Performances EDGE is a mature product (all vendors 2 to 4 times higher data throughput than GPRS NEs & features are ready since mid’2004) Interactive and Background classes*, Rel 99: Now EGPRS only (ECSD not implemented by Web browsing, mail attachment, chat, e- suppliers) commerce, file transfer,… at high data rate. Available for all bands 2005 Streaming with mobility QoS*, Rel 4: (850/900/1800/1900) Audio & Video streaming 2006/2007 Ensure the backward compatibility with Video on-demand. GPRS mobiles Conversational for data services*, Rel 5 & Rel 6: Videotelephony (*) EDGE has been standardised to enhance the data rate but not to enhance QoS service ( still best effort service) other features of GERAN will do it Objective: a higher data throughput thanks to a better spectral efficiency.Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 46
  47. 47. Theoretical performance of EDGE kbps 60 EGPRS (8-PSK) EGPRS (GMSK) 50 GPRS (GMSK) 40 30 20 10 0 CS-1 CS-2 CS-3 CS-4 MCS-9 MCS-8 MCS-7 MCS-6 MCS-5 MCS-4 MCS-3 MCS-2 MCS-1 EDGE can provide data services with maximum radio throughput of 235kbps using 4 TS.Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 47
  48. 48. Network impact of EDGE implementation New BSC Release P A GMSC 2106 B ABIS C MSC/ T U BSC BSC MSC HLR HLR BTS VLR S B Gb Gs Gr B T T S S Gi (IP) SGSN GGSN GGSN Um BTS SGSN AUC Upgrade Gn Gn PDN mobiles IP-Backbone Other PLMN EIR Network HW or SW Upgrade No Upgrade Gp New MobilesFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 48
  49. 49. Radio performances impact of EDGE implementation EDGE is main influence on GSM is on the radio interface. Upgrade of GSM network with EDGE will influence the radio conditions There is a need for carefull radio optimisation EDGE throughput is highly dependent on interferences (C/I), especially at the cells’ borderFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 49
  50. 50. EDGE vs UMTS for indoor coverage Robustness of Edge : – Compensation of radio propagation fluctuation thanks to Link Adaptation Instability of UMTS : – Throughput Drop due to building penetration and the mobile « Power rise » phenomenon. Throughput (kbps) Power limitation 320 UMTS 200 EDGE 900 Link adaptation BTS-MS distance (m) 500 1200Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 50
  51. 51. Dimensioning principles: radio Deploy EDGE on BCCH TRX (beacon channel) or not? Preferred configuration C/I mostly > 15dB For all values of C/I Choose the TRX that have the best C/I distribution If BCCH and non BCCH TRX have same C/I distribution try to optimize the network to increase the C/I. Small PS traffic BCCH If BCCH and non BCCH TRX have always slightly the same (1 to 5 TS) C/I distribution put EDGE on non BCCH with synthesized SFH (EDGE performances could not reach expected values, i.e. average of 30kbps/TS) Try to optimize the network to increase the C/I of non BCCH TRX. Important PS traffic If non BCCH TRX have always slightly the same C/I non BCCH distribution, put EDGE on non BCCH with synthesized (more than 5 TS) SFH EDGE performances could not reach expected values (i.e. average of 30kbps/TS)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 51
  52. 52. Dimensioning principles: transmission Objective: a higher data throughput thanks to a better spectral efficiency. More capacity needed in interfaces SGSN BTS GGSN Gr Abis Gb EDGE BSC TRX GSM/GPRS/EDGE Network Abis A Internet BTS BSC EDGE TRX MSC EDGE functionality Abis in network elements BTS EDGE EDGE handset TRX EDGE capable TRX need to be added, old BTS might have to be changed, BSC/PCU shall support EDGE capability. Re-dimensioning of the interface according to the traffic growth.Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 52
  53. 53. Dynamic Abis principle PCM transmission frames = permanent time slots for the CS traffic and signalling + Dynamic Abis Pool for the data (DAP)common for multiple Pool Dynamic AbisGSM/EDGE TRXs locatedunder the same BTS.Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 53
  54. 54. … and services evolution New services… Broadband video Digital video Location services Videotelephony Other killer app.? Videostreaming, ftp (big files) 2004 R’99 2005 Release 4 2006 Release 5 2007 Release 6 2008 Release 7 …and major performances & QoS enhancements to support it. ECSD: EDGE for CS (not yet adopted) SAIC: Increase spectral efficiency NACC: Reduce cell reselection Delayed TBF release: Reduce GPRS delays DTM: FLO: Simultaneous CS+PS Conversational PS, multiservice PFC: Generic access A/Gb: QoS service differentiation Technology convergenceFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 54
  55. 55. EDGE Status Worldwide Edge is a GSM - BSS feature to enable highest data throughput (proven technology) 38 devices are currently Edge compatible GSM Wireless Industry entirely committed to Edge 111 networks deploying Edge currently 35 commercially available Edge networksFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 55
  56. 56. Continuity of Service Without EDGE With EDGEData Speed Data Speed 384kbps 384kbps Service Continuity with reduced UMTS No Service UMTS throughput and latency Continuity 200kbps Edge Underlay 40kbps GPRS legacy 40kbps GPRS legacy Edge Introduction -> Bridging the Broadband Services gapFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 56
  57. 57. EDGE Service Portfolio Services FTP RTT GPRS EDGE UMTS (kbps) (sec) Best N/A • MMS Effort • Orange World >16 1-5 • Audio/Video <1 >128 Streaming • Video >64 N/A Messaging • File 64-384 N/A Downloads • Video >64 <0.2 Telephony Not possible Enabler technology Best Fitted technology Premium technologyFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 57
  58. 58. HSDPA as the next evolution after EDGE HSDPA is to UMTS what EDGE is to GPRS – New radio modulation offering higher bandwidth Data Speed 2Mbps UMTS to HSDPA is a factor 5 HSDPA x5 EDGE to UMTS is a factor 2 GPRS to EDGE is a factor 5 384kbps UMTS x2 200kbps EDGE x5 40kbps GPRSFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 58
  59. 59. Access Network Logical Layers GSM (EDGE) WAN UMTS (HSDPA) MAN Wi-MAX LAN Wi-Fi Bluetooth PAN UWBFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 59
  60. 60. Mobile Broadband Technology map IP Based Convergence IP Core Wi-Max Wi-Max 802.16d 802.16e Backhaul Wi-Fi 802.11 In-Building Rural Sub-Urban Urban Hotspots PICO Access MACRO MICRO Cellular Mobility GSM (EDGE) & UMTS (HSDPA)Frederic Michaud 14.12.04 EPFL – cours “Mobile network” 60
  61. 61. Conclusion EDGE deemed as a mature/stable/robust technology- – Edge as a key technology for in building coverage – Edge terminals are cheaper and more robust than UMTS (batteries…) – Complementary to UMTS in rural and suburban areas – International roaming with American/Asian operators that will transit to EDGE in Europe For usual radio conditions: – RLC throughputs around 40 kbps may be expected per timeslot (x4 for class 10 MS) – FTP throughputs around 35 kbps may be expected per timeslot (x4 for class 10 MS) This performance greatly depends on – The link adaptation algorithm of the manufacturer and parameter settings – The engineering solution chosen for EGPRS implementationFrederic Michaud 14.12.04 EPFL – cours “Mobile network” 61

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