Mobile Communications I

Transcription

1 Mobile Communications I Prof. Dr.-Ing. Rolf Kraemer chair owner telefon: fax: kraemer [ at ] ihp-microelectronics.com web:

2 Mobile Communications I Chapter 5.2: Cellular Communication - UMTS IMT-2000 Architecture Spreading and Scrambling Support of mobility HSPA

3 3G Enables Advanced Data Services Chapter 5.2 Page 261

4 Highlight of Current Activities(5/10)- Road Map of Mobile Communication CDMA2000 US 1xEV-DO Rev. 0 DL: 2.4Mbps UL:153.6kbps 1xEV-D0 Rev. A DL: 3.1Mbps UL: 1.8Mbps 1xEV-DV 3.1Mbps DO Rev. B ( Multi-Carrier DO) DL:46.5Mbps UL: 27Mbps UMB-UMB+ LBC DL: 100Mbps-1Gbps UL: Mbps SBC DL: 100Mbps-1Gbps UL: Mbps WCDMA Europe WCDMA R99/R4 384kb/s HSDPA 1.8M/14.4Mbps HSUPA 6-8Mbps HSPA+ DL:>40Mbps UL>10Mbps LTE-LTE+ DL:100Mbps UL:50Mbps HSPA+ LTE TD-SCDMA China R4 384kb/s HSPA Single-Carrier 2.8Mbps/ 2.2Mbps >10Mbps LTE-LTE+ DL:100Mbps UL:50Mbps Chapter 5.2 Page 262

5 Frequencies for IMT-2000 ITU allocation (WRC 1992) MHz IMT-2000 MSS IMT-2000 MSS Europe GSM 1800 DE CT T D D UTRA FDD MSS T D D UTRA FDD MSS China GSM 1800 IMT-2000 MSS IMT-2000 MSS Japan cdma2000 PHS W-CDMA MSS cdma2000 W-CDMA MSS North America PCS MSS MSS MHz rsv. Chapter 5.2 Page 263

6 IMT-2000 family Interface for Internetworking IMT-2000 Core Network ITU-T GSM (MAP) ANSI-41 (IS-634) IP-Network Initial UMTS (R99 w/ FDD) Flexible assignment of Core Network and Radio Access ANSI-41: Systems Interworking IMT-2000 Radio Access ITU-R IMT-DS (Direct Spread) UTRA FDD (W-CDMA) 3GPP IMT-TC (Time Code) UTRA TDD (TD-CDMA); TD-SCDMA 3GPP IMT-MC (Multi Carrier) cdma2000 3GPP2 IMT-SC (Single Carrier) UWC-136 (EDGE) UWCC/3GPP IMT-FT (Freq. Time) DECT ETSI Chapter 5.2 Page 264

7 More Standardisation 3GPP develops standards in form of releases Release-99 has been introduced, Release 5 and Release 6 are now being widely implemented (HSDPA/HSUPA) LTE is release 8 and LTE-Advanced Release 10 The evolution towards a full IP based IMT-2000 is reflected in the different release states Release 4: introduces QoS within the core network, mobile execution environments (MExE), new service architectures Release 5: introduces a fundamentally different core network as a full IP based network (convergence from today s CS-Architectures); IETF will be more and more important for service levels of IMT-Releases; parts of SS7 signalling architecture will be replaced by SIP (session initialisation protocol) for multimedia streaming; additionally introduction of HSDPA (High speed downlink packet access 8-10Mb/s) Release 6: additionally MIMO structures for performance increase and better radio spectrum use Currently first roleout of LTE (Long Term Evolution) is ongoing. LTE+ (advanced) standadization is completed. Data communication up to 140 Mb/s should become possible using MIMO and distributed MIMO techniques. Multi-Hop communication should allow better coverage at the cell edges Chapter 5.2 Page 265

8 Licensing Example: UMTS in Germany, 18. August 2000 UTRA-FDD: Uplink MHz Downlink MHz duplex spacing 190 MHz 12 channels, each 5 MHz UTRA-TDD: MHz, MHz; 5 MHz channels Coverage: 25% of the population until 12/2003, 50% until 12/2005 Sum: billion Chapter 5.2 Page 266

9 UMTS - architecture (Release 99 used here!) UTRAN (UTRA Network) (UTRA: Universal Terrestrial Radio Access) Cell level mobility Radio Network Subsystem (RNS) Encapsulation of all radio specific tasks UE (User Equipment) CN (Core Network) Inter system handover Location management if there is no dedicated connection between UE and UTRAN U u I u UE UTRAN CN Chapter 5.2 Page 267

10 UMTS - domains and interfaces I UMTS domains describe functionalities Home Network Domain Z u USIM Domain C u Mobile U u Access I u Equipment Network Domain Domain Serving Network Domain Y u Transit Network Domain Core Network Domain User Equipment Domain Infrastructure Domain User Equipment Domain Assigned to a single user in order to access UMTS services USIM contains all personal data as well as an UMTS SIM Application Toolkit (interpreter for flexible creation of new services) Infrastructure Domain Shared among all users Offers UMTS services to all accepted users Chapter 5.2 Page 268

11 UMTS - domains and interfaces II Universal Subscriber Identity Module (USIM) Functions for encryption and authentication of users Located on a SIM inserted into a mobile device Mobile Equipment Domain Functions for radio transmission User interface for establishing/maintaining end-to-end connections Access Network Domain Access network dependent functions Core Network Domain Core network dependent functions Serving Network Domain Network currently responsible for communication Home Network Domain Location and access network dependent functions Chapter 5.2 Page 269

12 UMTS - Spreading and scrambling of user data Constant chipping rate of 3.84 Mchip/s Different user data rates supported via different spreading factors higher data rate: less chips per bit and vice versa User separation via unique, quasi orthogonal scrambling codes users are not separated via orthogonal spreading codes much simpler management of codes: each station can use the same orthogonal spreading codes precise synchronization not necessary as the scrambling codes stay quasiorthogonal data 1 data 2 data 3 data 4 data 5 Separation of connections spr. code 1 spr. code 2 spr. code 3 spr. code 1 spr. code 4 Separation of users scrambling code 1 3,84Mchip/s scrambling sender 1 code 2 sender 2 On air addition of signals Chapter 5.2 Page 270

13 UMTS - OVSF (Orthogonal Variable Spreading Factor) coding Generator X,X X 1,1,1,1 1,1 1,1,-1,-1 1 X,-X 1,-1,1,-1 SF=n SF=2n 1,-1 1,-1,-1,1 1,1,1,1,1,1,1,1 1,1,1,1,-1,-1,-1,-1 1,1,-1,-1,1,1,-1,-1 1,1,-1,-1,-1,-1,1,1 1,-1,1,-1,1,-1,1,-1 1,-1,1,-1,-1,1,-1,1 1,-1,-1,1,1,-1,-1,1 1,-1,-1,1,-1,1,1, SF=1 SF=2 SF=4 SF=8 Chapter 5.2 Page 271

14 UMTS - Example of OVSF use for 4 connections with different bit-rates 1 1,1 1,-1 1,1,1,1 1,1,-1,-1 1,-1,1,-1 1,-1,-1,1 1,1,1,1,1,1,1,1 1,1,1,1,-1,-1,-1,-1 1,1,-1,-1,1,1,-1,-1 1,1,-1,-1,-1,-1,1,1 1,-1,1,-1,1,-1,1,-1 1,-1,1,-1,-1,1,-1,1 1,-1,-1,1,1,-1,-1,1 1,-1,-1,1,-1,1,1, SF=1 SF=2 SF=4 SF=8 Chapter 5.2 Page 272

15 UMTS - FDD frame structure 10 ms µs µs µs Radio frame Time slot Pilot TFCI FBI TPC Data chips, 10 bits Data 2560 chips, 10*2 k bits (k = 0...6) DPDCH TPC TFCI Data 2 Pilot DPCCH DPDCH DPCCH 2560 chips, 10*2 k bits (k = 0...7) uplink DPCCH uplink DPDCH downlink DPCH Slot structure NOT for user separation but for synchronisation for periodic functions! W-CDMA MHz uplink MHz downlink chipping rate: Mchip/s soft handover QPSK complex power control (1500 power control cycles/s) spreading: UL: 4-256; DL: FBI: Feedback Information TPC: Transmit Power Control TFCI: Transport Format Combination Indicator DPCCH: Dedicated Physical Control Channel DPDCH: Dedicated Physical Data Channel DPCH: Dedicated Physical Channel Chapter 5.2 Page 273

16 UMTS - UTRAN architecture RNS RNC: Radio Network Controller RNS: Radio Network Subsystem UE 1 Node B I ub I u RNC CN UE 2 Node B UTRAN comprises several RNSs UE 3 Node B Node B I ub I ur RNC Node B can support FDD or TDD or both RNC is responsible for handover decisions requiring signalling to the UE Cell offers FDD or TDD Node B RNS Chapter 5.2 Page 274

17 UMTS - UTRAN functions Admission control Congestion control System information broadcasting Radio channel encryption Handover SRNS moving (Serving RNS) Radio network configuration Channel quality measurements Macro diversity Radio carrier control Radio resource control Data transmission over the radio interface Outer loop power control (FDD and TDD) Channel coding Access control Chapter 5.2 Page 275

18 UMTS - Integrated Core network: architecture BTS A bis BSS I u VLR BSC MSC GMSC PSTN Node BTS B I u CS AuC EIR HLR Node B I ub GR Node B RNC SGSN G n GGSN G i Node B RNS I u PS CN Chapter 5.2 Page 276

19 UMTS - Core network: protocols Towards All-IP Networks VLR RNS MSC GSM-CS backbone GMSC PSTN/ ISDN HLR RNS Layer 3: IP Layer 2: ATM Layer 1: PDH, SDH, SONET UTRAN SGSN GPRS backbone (IP) SS 7 CN Chapter 5.2 Page 277 GGSN PDN (X.25), Internet (IP)

20 UMTS - Core network The Core Network (CN) and thus the Interface I u, too, are separated into two logical domains: Circuit Switched Domain (CSD) Circuit switched service incl. signaling Resource reservation at connection setup GSM components (MSC, GMSC, VLR) I u CS Packet Switched Domain (PSD) GPRS components (SGSN, GGSN) I u PS Release 99 uses the GSM/GPRS network and adds only a new radio access! Helps to save a lot of money Much faster deployment Not as flexible as newer releases (5, 6) Chapter 5.2 Page 278

21 UMTS - protocol stacks (user plane) Circuit switched Packet switched UE U u UTRAN I u CS 3G MSC apps. & protocols RLC MAC radio RLC MAC radio SAR AAL2 ATM SAR AAL2 ATM UE U u UTRAN I u PS 3G apps. & protocols SGSN IP, PPP, IP tunnel PDCP PDCP GTP GTP GTP RLC RLC UDP/IP UDP/IP UDP/IP MAC radio MAC radio AAL5 ATM AAL5 ATM L2 L1 RLC: Radio Link Control SAR: Segmentation&Reassembly ATM: Asynchonous Transfer Mode GTP: GPRS Tunneling Protocol PDCP: Packet Data Conversions Protocol AAL2: ATM-Adaptation Layer 2 (High Quality) AAL5: AAL with best effort service G n 3G GGSN IP, PPP, GTP UDP/IP L2 L1 Chapter 5.2 Page 279

22 UMTS - Support of mobility: macro diversity Multicasting of data via several physical channels Enables soft handover UE Node B FDD mode only Uplink simultaneous reception of UE data at several Node Bs Node B RNC CN Reconstruction of data at Node B, SRNC or DRNC Downlink Simultaneous transmission of data via different cells SRNC: Serving RNC DRNC: Drift RNC Different spreading codes in different cells Chapter 5.2 Page 280

23 UMTS - Support of mobility: handover From and to other systems (e.g., UMTS to GSM) This is a must as UMTS coverage will be poor in the beginning RNS controlling the connection is called SRNS (Serving RNS) RNS offering additional resources (e.g., for soft handover) is called Drift RNS (DRNS) End-to-end connections between UE and CN only via I u at the SRNS Change of SRNS requires change of I u Initiated by the SRNS Controlled by the RNC and CN Node B SRNC I u CN UE Node B I ub DRNC I ur SRNC: Serving RNC DRNC: Drift RNC I ub Chapter 5.2 Page 281

24 Example handover types in UMTS/GSM UE 1 Node B 1 RNC 1 3G MSC 1 UE 2 Node B 2 I ub I ur I u UE 3 Node B 3 RNC 2 3G MSC 2 UE 4 BTS BSC 2G MSC 3 A bis A Chapter 5.2 Page 282

25 UMTS - Cell breathing CDM systems: cell size depends on current load Additional traffic appears as noise to other users If the noise level is too high users drop out of cells Chapter 5.2 Page 283

26 UMTS - Cell Breathing Chapter 5.2 Page 284

27 UMTS - Conclusions UMTS is part of the IMT-2000 initiative driven by 3GPP It is a continuously changing system that develops evolutionary towards an ALL-IP network for integrated data, voice and multi-media services In Europe currently Release 13 are introduced Release 99 has been the evolution path from GSM to UMTS that saved a lot of financial resources and was a smooth transfer path GPRS services will be enhanced (e.g. EDGE) to serve rural areas for lower cost UMTS is a big step forward towards UPN even though is will not be achieved in a single step The creation of 3GPP to moderate the convergence process was a good means to approach a user demanded long term goal Chapter 5.2 Page 285

28 UMTS - HSDPA Enabling Technologies How will HSDPA address the limitations of Release 99? Extension of DSCH (downlink shared channel) Multi-Code operation (more than on spreading code can be accumulated) Adaptive modulation and coding QPSK and 16-QAM Coding from R=1/3 to R=1 Fast feedback of channel condition Improve transmission efficiency Fast retransmission and Physical Layer HARQ Fast resource management Node B scheduling Reduce transmission latency 2 ms TTI Chapter 5.2 Page 286

29 UMTS HSDPA: Shared Channel for Data HS-PDSCH: High Speed Physical Downlink Shared Channel Chapter 5 Page 287

30 UMTS HSDPA: Multi-Code Operation Fixed Spreading Factor SF=16 (Typical Spreading Factor for 128 kbps in Release 99) 1-15 codes can be reserved for HS-PDSCH Can be TDM or CDM between users Chapter 5.2 Page 288

31 UMTS HSDPA: Adaptive Modulation and Coding Coding from R=1/3 to R=1 HSDPA supports 16-QAM modulation 4 bits per symbol versus 2 bits per symbol with QPSK 2 bits Modulator (QPSK) 3,84 Mcps Spreading 4 bits Modulator 3,84 Mcps (16-QAM) Spreading Chapter 5.2 Page 289

32 UMTS HSDPA: Hybrid Automatic Repeat Request (HARQ) Scheme: combining ARQ and Forward Error Correction FEC decoding based on all unsuccessful transmissions Simple Stop-and-Wait (SAW) protocol Two basic schemes: Chase Combining same data block is sent at each retransmission Incremental Redundancy (IR) Additional Redundant Information sent at each retransmission Chapter 5.2 Page 290

33 UMTS HSDPA: HARQ Illustration Chapter 5.2 Page 291

34 The evolution of UTRAN UTRAN (UMTS) EPC and E-UTRAN (LTE) GGSN EPC SGSN MME / S-GW / P-GW MME / S-GW / P-GW S1 S1 RNC RNC S1 S1 enb X2 enb E-UTRAN X2 X2 NB NB NB NB enb EPC: Evolved Packet Core; MME: Mobility Management Entity; E-Utran: Enhanced UTRAN Chapter 7 Page 292

35 System architecture of LTE-Rel8 (source: TR ) EPC MME / S-GW / P-GW S1 MME / S-GW / P-GW S1 enb provides E-UTRA N-Plane and C-Plane protocol terminations towards the UE X2 connects enbs as mesh network, enabling direct communication between the elements and eliminating the need to tunnel data back and forth through a (RNC) enb S1 X2 S1 enb E-UTRAN S1 connects E-UTRAN to EPC (enbs are connected to MME and S-GW elements through a many-to-many relationship) X2 X2 enb S-GW: Service Gateway; P-GW: Packet Gateway, MME: Mobility Management Entity Chapter 7 Page 293

36 OFDM vs. OFDMA Data is modulated using sub-carriers and time slots Enables high data rate in a wireless channel Each subscriber can get different quantity of data Enables optimal balance of data forwarding between subscribers OFDM OFDMA user 1 user 2 user 3 subcarriers subcarriers symbols (time) *LTE OFDM symbol time: 71.3µs (useful: 66.7µs) symbols (time) Chapter 7 Page 294

37 Multi-cell Network MIMO Data S 1,S 2 Channel Info feedback Precoding Network backhaul w S 11 1 w12 S2 w21s 1 w22 S2 h 11 h 12 h 22 h 21 Less co-channel interference, more signal Better cell edge performance Requirements: Increased uplink feedback overhead Synchronization to more than one cell Chapter 7 Page 295 Zero forcing example: w11 w12 h11 h12 w w h h

38 Relay Technology BS Coverage Area RS Providing Coverage Extension Relays beneficial for low SINR (cell-edge) UEs* BS MS RS Coverage Area MS RS MS MS MS Relays also useful for coverage holes, indoor coverage and underground tunnels etc. *F. Khan, Capacity and Range Analysis of Multi-Hop Relay Wireless Networks, Chapter 7 Page 296 IEEE Vehicular Technology Conference Fall 2006.