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3G and 4G Wireless – Advances and Challenges

3G and 4G Wireless – Advances and Challenges

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3G and 4G Wireless – Advances and Challenges

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  1. 3G and 4G Wireless – Advances and Challenges

  2. 3G and 4G Wireless – Advances and Challenges • Where are we? • 3G Wireless Summary • Where do we Want to go? • Evolution to Seamless Networking • 4G Wireless • Challenges The one who stays still is left behind

  3. Where are We? • Classic Wireline MaBell Public Switched Telephone Network (PSTN) • US Universal coverage achieved early 1980’s • “Wireless” First Generation Analog Systems • Speech • AMPS, TACS • Second Generation Digital Systems • Enhanced Capacity • CDMA, D-AMPS, TDMA, GSM, DECT, PDC • 2.5 Generation Systems • Low Speed Data • GPRS, EDGE • Third Generation Systems • “INTERNET” on Wireless • WiFi/HyperLAN <-> WiMAX/HyperWAN <-> CDMA2000/WCDMA • Evolution to All IP Network including VoIP

  4. Representative Wireless Standards • GSM/TDMA • Time Division Multiplexing based access • CDMA • Code Division Multiplexing based access • OFDM • Orthogonal Frequency Division Multiplexing Many toys to play with

  5. TDMA/FDMA Give the same air to all

  6. CDMA X I I I Channelization code: Separate xmissions from a single source from each other Scrambling code: separate different sources from each other Spreading Code = Channelization code x Scrambling code All persons are created equal

  7. Multipath Arrival of Signals

  8. CDMA Rake Receiver

  9. Orthogonal Frequency Division Multiplexing (OFDM) • Successor to Frequency Hopping and Direct Sequence CDMA • Capability to cancel multipath distortion in a spectrally efficient manner without requiring multiple local oscillators (802.11a and 802.16) • Based on use of IFFT and FFT • Frequency orthogonality as compared to code orthogonality in CDMA using Walsh Code

  10. 3G Services Who is first? – the customer; who is second? - No one

  11. Key Mobility Services • Multimedia Messaging Services (MMS) • Text, sounds, images, and video • Transition from Short Message Service (SMS) • Open Internet standards for messaging • Web Applications • Information portals • Wireless Markup Language (WML) with signals using Wireless Application Protocol (WAP) • Location Communications Services • Location Awareness Based • Personalization of information presentation format • Service capability negotiations (MExE environment)

  12. Customized Application for Mobile Enhanced Logic (CAMEL) • CAMEL = IN + Service portability (incl mobility and roaming) • Virtual Private Network (VPN) • Mobile user <-> ISP <-> corporate server • Mobility, Security, Capacity and quality • Prepaid, Usage Limitations, Advanced Routing Services • Virtual Home Environment (VHE) • Subscriber profile, charging information, Service information, numbering information • Integration of array of services, content conversion to heterogeneous services, network user profile, location aware services Take the claims with a grain of salt

  13. GSM Network Billing Center STP HLRAuC BSS SCP gsm SCF SSP PSTN/ISDN IN ISUP C Gw-MSC C, D E, ISUP Call SMS-GW VLR MSC GSM04.08 A UE Circuit domain

  14. GSM & GPRS Billing Center STP HLRAuC BSS SCP gsm SCF SSP IP Services PDN PSTN/ISDN IN ISUP Gi Gc C Gw-MSC GGSN Data, voice, video call Ga CGw C, D E, ISUP Gn Call Ga SMS-GW Gr VLR MSC SGSN GSM04.08+ GSM04.08+ A Gb UE Packet domain Circuit domain

  15. WCDMA/UMTS Billing Center STP HLR+AuC UTRAN SCP gsm SCF SSP IP Services PDN PSTN/ISDN IN, CAMEL ISUP Gi+ Gc+ C Gw-MSC GGSN Data, voice, video call Ga+ C+, D+ CGw E+, ISUP Gn+ Call Ga+ SMS-GW Gr+ VLR 3G-MSC 3G-SGSN GSM04.08++ GSM04.08++ Iu-cs Iu-ps UE Packet domain Circuit domain

  16. EDGE UMTS GSM/UMTS Bit rate, Mobility and Services High (Car / Train) GSM HSCSD GPRS Mobility Voice Text Messaging CS Data Fax Low (stationary) Bit Rate, Kbps 384.0 EDGE UMTS 2 Mb/s 9.6 14.4 76.0 GPRS HSCSD

  17. 3G Evolution 2.5G 3.5G GPRS 170 kbps EDGE 473 kbps GSM HSCSD 15.2 kbps EDGE Ph2 GRAN 473 kbps TDMA CDPD 43.2 kbps TD-SCDMA Ph 2 2 Mbps TD-SCDMA 284 kbps WCDMA TDD 2 Mbps WCDMA FDD 2 Mbps PDA/PDC-P 14.4 kbps WCDMA HSDPA 10 Mbps 1XEV-DO (HDR) 2.4 Mbps CDMA2000 1x 307 kps cdmaOne 76.8 kbps 1XEV-DV (HDR) 5.4 Mbps HyperLAN2 54 Mbps Harmonized HyperLAN2 And IEEE 802.11a WLAN IEEE 802.11b 11 Mbps IEEE 802.11 a/h 54 Mbps WiMAX/HyperMAN also in the mix Ref: Honkasalo et al, WCDMA and WLAN for 3G and Beyond, IEEE Wireless Communication, Apr 2002

  18. Some Representative Current Wireless Options • 3G Cellular (WCDMA) • Frequency Division Duplex (FDD): Uplink and Downlink are separated in frequency – (“symmetric”) • Time Division Duplex (TDD): Uplink and Downlink are separated in time – allows “asymmetric” traffic (adjust time slots in uplink and downlink) • 3G Cellular (CDMA2000) • Wi Fi • 802.11a and 802.11b; HyperLAN2 • 2.4 GHz band • WiMAX • 802.16d (fixed); 802.16e (“portable”) • 5.8 GHz band; 10 – 20 Mbps symmetrical BW • Blue Tooth • RF based LAN technology; 20-30 feet coverage • 2.4 GHz band Darwin’s Theory of Evolution and Survival of the fittest

  19. 3G WCDMA • Release 99 • Release 4 • Release 5 • Domains, Protocols, and Channels • Radio Resource Management • Network Dimensioning and Optimization • Quality of Service (QoS0 and Location Services The favored twin sister of CDMA2000

  20. Release 99 • Radio Bearer Negotiations • Traffic Classes • Complex Scrambling • Speech Codec – (eight) Adaptive Multi Rate (AMR) • Battery Life • Transmission “spatial/antenna” diversity • Compressed Mode • Measurements in multiple frequency • Use of transmission time reduction techniques • # PDP Contexts per IP Address • QPSK; coherent detection; Rake receiver • Short and Long Spreading Codes • Multicall – several simultaneous CS calls with dedicated bearers of independent traffic and performance characteristics • Customized Application for Mobile network Enhanced Logic (CAMEL) Phase 3 A lot to gobble

  21. Release 4 • Bearer Independent Core Network • Tandem Free Operation (TFO), Transcoder Free Operation (TrFO), and Out of Band Transcoder Control (OoBTC) • Low Chip Rate TDD Operation • Network Assisted Cell Change • FDD Repeater • NodeB Synchronization for TDD • IPv6 packet switched network supporting both real time and non-real time traffic • Session Initiated Protocol (SIP) replacing SS7 • Home Subscriber Server (HSS) • MSC/VLR -> MSC server (mobility management) and MGW (Connection management subtasks) • Multimedia Message Service (MMS) environment

  22. Release 5 • IP Transport in UTRAN • High Speed Downlink Packet Access (HSDPA) (upto 10 Mbps) • Intra Domain Connection to Multiple CN Nodes (Iuflex) • IP Multimedia CN Subsystem (IMS) • “Guaranteed” End to End (E2E) QoS in the PS domain • Global Text Telephony • Support for Real Time Services in packet domain • CAMEL Phase 4

  23. HSDPA • Peak Data rate > 10 Mbps • Same spectrum by both voice and data • Up to 12 spreading codes for High Speed DSCH (HS-DSCH) • Fast link Adaptation • Both code and time division for channel sharing • Transmission Time interval 2 ms • Hybrid Automatic Repeat reQuest (HARQ) • Automatic optimizations to Channel Quality Indicator (CQI) • QPSK and 16 QAM modulation at 3.84 Mhz symbol; spreading factor fixed to 16 • Incremental Redundancy or chase combining (CH) • New DPCCH2 in uplink primarily for HARQ channel state info

  24. WCDMA Domains Standardization of architecture (domains) and standardization of protocols (strata)

  25. WCDMA Protocol Layers

  26. WCDMA L1, L2, and RRC Sublayer

  27. WCDMA Channels Transport Channels: how information transferred over the radio interface Logical Channels: Type of information transferred over the radio interface Channels made by soft hats

  28. Mapping Between Channels N to M

  29. WCDMA Channel Usage Examples Flexibility comes with responsibility

  30. Radio Resource Management • Power Control • Handover • Access Control • Load and Congestion Control • Packet Scheduling

  31. WCDMA Power Control (near = far) Uplink and downlink (1500 Hz) Open Loop Power Control Closed Loop Power Control Outer Loop Power Control Equal Opportunity Administration (EOA)

  32. WCDMA Handovers Softer Soft Hard and Inter-frequency handovers Intersystem cell-reselection “Equivalent PLMN mode” (autonomous cell re-selection (packet) idle mode)

  33. Handover Algorithm A relay race with multiple batons

  34. Network Dimensioning and Optimization • Dimensioning Criteria • Coverage, Capacity, Quality of Service • Dimensioning • Link budget, capacity (hard and soft) and load factor • Estimation of average interference power • Coverage end Outage probabilities • Optimization • Performance Requirements • Antenna adjustments, neighbor lists, scrambling codes Don’t force a round peg in a square hole

  35. WCDMA Quality of Service (Qos) • Dynamic Negotiations of properties / Services of radio bearer • Thruput, transfer delay, data error rate • Authentications One way communications is no communications

  36. Location Services (LCS) Cell ID based Observed Time Difference Arrival – Idle Period Downlink (OTDOA-IPDL) Network Assisted GPS You can run but you cannot hide

  37. Why Move Towards 4G? • Limitation to meet expectations of applications like multimedia, full motion video, wireless teleconferencing • Wider Bandwidth • Difficult to move and interoperate due to different standards hampering global mobility and service portability • Primarily Cellular (WAN) with distinct LANs’; need a new integrated network • Limitations in applying recent advances in spectrally more efficient modulation schemes • Need all digital network to fully utilize IP and converged video and data Incessant human desire to reach the sky

  38. Where Do We Want to Go? • Seamless Roaming • Integrated “standard” Networks • Mobile Intelligent Internet • Onwards to (Ultra) Wideband Wireless IP Networks We are no longer in Kansas, Toto

  39. Upcoming • 3.5 G • Evolved radio Interface • IP based core network • 4G • New Air Interface • Very high bit rate services • Convergence of Wireline, Wireless, and IP worlds And Now for Something Completely Different

  40. Legacy mobile signaling Network Alternative Access Network CSCF R-SGW Mw Mh Ms Mm HSS CSCF Mg Cx Mr MRF Gi MGCF T-SGW Gi Mc PSTN/ Legacy/External Gi MGW MGW Iu Nb Mc Mc MSC Server GMSC Server T-SGW Nc 3G All-IP Reference Architecture Applications & Services Multimedia IP Networks SCP HLR CAP Gi Gr Gc SGSN Gn GGSN Iu MT UTRAN TE R Uu Gp Signalling Interface GGSN Gn Signalling and Data Transfer Interface Other PLMN SGSN

  41. Wireless Data Server Wireless Data Server PSTN/ISDN Internet/Intranet/ISP PSTN/ISDN Application servers Internet/Intranet/ISP Application servers www, email www, email IP Firewall IP Firewall IP IP PSTN/ISDN GGSN GGSN CSCF MGCF SGW HLRAuC HSS (G)MSC Server 3G-MSC 3G-MSC MGW MGW PCM PCM IP SS7 SS7 SGSN SGSN MRF GGSN ATM GTP+/IP ATM GTP+/IP Iur Iur Iub Iub Iub Iub RNC RNC RNC RNC N_B N_B N_B N_B WCDMA 3G Evolution to All-IP Network UTRAN

  42. 3.5G Radio Network Evolution • High Data rate, low latency, packet optimized radio access • Support flexible bandwidth upto 20 MHz, new transmission schemes, advanced multi-antenna technologies, and signaling optimization • Instantaneous peak DL 100 Mb/s and UP 50 Mb/S within 20 MHz spectrum • Control plane latency of < 100 ms (camped to active) and < 50 ms (dormant to active) • > 200 users per cell within 5 MHz spectrum • Spectrum flexibility from 1.25 MHz to 20 MHz • Eliminate “dedicated” channels; avoid macro diversity in DL • Migrate towards OFDM in DL and SC-FDMA in UL • Support voice services in the packet domain • Adaptive Modulation and Coding using Channel Quality Indicator (CQI) measurements

  43. 3.5G WCDMA Evolved System Architecture Source: www.3gpp.org

  44. Key 3G and 4G Parameters

  45. Key 4G Mobility Concepts • Mobile IP • VoIP • Ability to move around with the same IP address • IP tunnels • Intelligent Internet • Presence Awareness Technology • Knowing who is on line and where • Radio Router • Bringing IP to the base station • Smart Antennas • Unique spatial metric for each transmission Wireless IP <---> IP Wireless

  46. 4G Networks Advances • Seamless mobility (roaming) • Roam freely from one standard to another • Integrate different modes of wireless communications – indoor networks (e.g., wireless LANs and Bluetooth); cellular signals; radio and TV; satellite communications • 100 Mb/se full mobility (wide area); 1 Gbit/s low mobility (local area) • IP-based communications systems for integrated voice, data, and video • IP RAN • Open unified standards • Stream Control Transmission Protocol (SCTP) • Successor to “SS7”; replacement for TCP • Maintain several data streams within a single connection • Service Location Protocol (SLP) • Automatic resource discovery • Make all networked resources dynamically configurable through IP-based service and directory agents The demise of SS7

  47. 4G Networks Advances – cont’d • Diameter • Successor to “Radius” • Unified authentication, authorization, and accounting (AAA) • Integrated LAN card and Subscriber Identity Modules (SIMs) • HSS • Unified Subscriber Information • Application developers, Service providers, and content creators Expand beyond the circle

  48. Key Challenges • Spectral Efficiencies • Challenge Shannon’s fundamental law of data communications (BW, Sig/No) • Hardware Frequency Synthesis techniques esp. for Frequency Hop (FH) systems • Traffic characteristics management (burstiness, directionality) • Multi Carrier Modulation (MCM) • Baseband process using parallel equal bandwidth subchannels • MC-CDMA; OFDM • Quadrature Phase-Shift Keying (QPSK); Multilevel Quadrature Amplitude Modulation (M-QAM); Fast Fourier Transform (FFT) • Add cyclic extension or guard band to data • Challenges of Inter Symbol Interference (ISI) and Peak to Average Ratio (PAVR) No pain, no gain

  49. Key Challenges - cont’d - 1 • Signal Processing and optimizations • Handling extremely large number of users • Synchronous and asynchronous transmissions • Orthogonality / correlation of large number of codes • Spectrum Pollution • Multi path re-enforcement / interference • Multi User Detection (MUD) and Adaptive Interference suppression techniques (ISI and MAI)

  50. Key Challenges - cont’d - 2 • Extremely Fast Arithmetic (esp. multiplication) • N Dimensional vector spaces • IFFT, FFT • Advanced DSP’s for parsing and processing data • Smart / Intelligent Antennas • Dynamically adjust beam pattern based on CQI • Switched beam Antennas; adaptive arrays • Coverage limitations due to high frequencies (> 5 GHz) Manage Entropy