ComNets. Four Generations of Digital Mobile Radio Networks - From 2G to 5G Systems - Bernhard Walke

Transcription

1 Four Generations of Digital Mobile Radio Networks - From 2G to 5G Systems - Bernhard Walke Communication Networks (ComNets) Research Group RWTH Aachen University, Germany Oct. 23, 2015 ComNets

2 Content 1. Mobile Radio Networks and Services 2. Frequency Spectrum, Radio Propagation 3. Transmission Technology 4. Techniques for Increasing Capacity 5. Future (5G) Mobile Systems Architecture 6. Summary ComNets 2

3 Growth of transmitted Data world-wide - Mobile Video is the main application - Cumulated Annual Growth CAGR Exa = 10 exp 16 Figures in parentheses refer to 2014, 2019 traffic share. Source: Cisco VNI Mobile, 2015 ComNets

4 World-wide Standardized Digital Mobile Radio Systems Mobile System: 1989: GSM (Global System for Mobile) 2G khz channel width, 15 kbps 2001: GPRS (General Packet Radio Service) in GSM 2G - 64 kbps 2004: EDGE (Enhanced Data Rate for GSM Evolution) 2.5G 256 kbps 2003: UMTS (Universal Mobile Telecom. System) 3G 2 MHz 1 Mbps 2006: HSPA+ (High Speed Packet Access) 3.5G 2 MHz channel width, 15 Mbps 2009: LTE (Long Term Evolution) 4G 20 MHz channel width 100 Mbps 2014: LTE-A (Long Term Evolution Advanced) 4.5G n x 20 MHz 1 Gbps 2020: 5G (Self-Organizing Mobile Network for Internet of Things) 10 Gbps Wireless Systems: 1999: WLAN (Wireless Local Area Network) 1, 2, 5 MHz - < 200m, Mbps 2000: DECT (Digital European Cordless Telecommunications) 2 MHz 50m 2003: Bluetooth 1, 2 MHz 10m ComNets 4

5 Mobile Radio Network Architecture (Example UMTS) Andere Mobilfunknetze Öffentl. Telefonnetz/ISDN USIM Datennetze/ Internet USIM MS RAN CN Core Network Transport functions, mobility management, Subscriber data base, service control, etc. Radio Access Network Radio technology specific fixed network functions (Radio Resource Management, etc.) Mobile Station UMTS Subscriber Identity Module Radio Interface (Radio transmission) Service control and user interface. Contains subscriber specific data Enables authentified access to the mobile network. Important interfaces between function blocks System architecture 5

6 Capacity Required depends on Operations Area Source: J. Zander, P. Mähönen: Riding the Data Tsunami in the Cloud: Myths and Challenges in Future Wireless Access, IEEE Communications Magazine, March 2013, ComNets

7 Content 1. Mobile Radio Networks and Services 2. Frequency Spectrum, Radio Propagation 3. Transmission Technology 4. Techniques for Increasing Capacity 5. Future (5G) Mobile Systems Architecture 6. Summary ComNets 7

8 Betriebsfrequenzen von 2G - 4G Mobilfunksystemen The radio interface of mobile terminals must be a standard to enable world wide usability. Four frequency bands are defined for mobile use by ITU-R: For large cells: MHz MHz For small cells: MHz MHz In some regions there is more spectrum available ComNets 8th Würzburg Workshop on IP, July 21-22,

9 Assigned and Candidate Bands according to ITU-R WRC 2015 New assignments for 5G will only happen at WRC2019 Spectrum preferred by NGMN a GHz (e.g GHz, GHz) b. 20 GHz 30 GHz (e.g GHz, GHz, c GHz (e.g GHz, GHz, GHz, GHz, 2008 ComNets 8th Würzburg Workshop on IP, July 21-22,

10 Atmospheric attenuation vs. frequency from ITU-R Report M ComNets 8th Würzburg Workshop on IP, July 21-22,

11 Path loss (signal attenuation) during radio signal propagation n n n n Receive signal strength follows a 3rd to 4th exponent law of distance between sender and receiver. The receiver needs a minimum signal threshold to be able to decode incoming signals. Higher transmit power increases cell radius. Path loss increases with higher carrier frequency. Path loss [db] Cell border pico cell Increased transmit power Cell border Micro cell Distance [m] Increased carrier frequency Minimum required receive level Antennenstandort der Basisstation 2008 ComNets 8th Würzburg Workshop on IP, July 21-22,

12 Funkzellen in Innenstadt und Umland Je größer der Datenverkehr / qm, desto kleiner muss die Zelle sein. Bei gegebener Frequenzausstattung hängt die Datenkapazität der Zelle nicht vom Zellradius ab. Je größer der Zellradius, desto kleiner die Datenkapazität / qm. Pico Zelle: Stadtzentrum: 100 m Radius. Macro Zelle: Stadtrand, 0,5-5 km Radius An Orten mit hohem Datenverkehr versorgt eine Basisstation drei Zellen: Drei-Sektorzelle ComNets 8th Würzburg Workshop on IP, July 21-22,

13 Signal strength in a cell is limited by interference power of neighbor cells transmitting on same frequency. db SINR = Signal to Interference and Noise Ratio. Example: Base station with three sectors (3 cells) Interference is highest at cell border (blue areas), where data rate is lowest. ComNets

14 Areal Radio Coverage by Pico versus Macro Cells Pico Cells Signal level above red circle area only appears in Macro Cells Macro Cells (a) (b) Downlink Interference (dbm) für typical real systems (a) Pico-Cells in Manhattan Grid (Cell Radius is 100m) Walfish-Ikegami path loss model; Transmit power: 30dBm (1W). (b) UMTS: Macro Cells (Cell radius is 500m); Okumura-Hata path loss model; Transmit power: 40dBm (10W). Pico Cell Networks in mm-wave Frequencies are possible

15 Content 1. Mobile Radio Networks and Services 2. Frequency Spectrum, Radio Propagation 3. Transmission Technology 4. Techniques for Increasing Capacity 5. Future (5G) Mobile Systems Architecture 6. Summary ComNets 15

16 Circuit switching (TDMA) in GSM A periodic frame with 8 time slots (0..7) is transmitted on a GSM frequenc channel Each periodic time slot is a circuit switched physical TDMA channel. A time slot carries a Normal Burst or a signaling burst ms Frequency/MHz TDMA Frame Downlink, DL time slot data bits training data bits Normal Burst 57 bit bit 915 Duplex distance Gap between uplink and downlink 3 tail bits 1 toggle bit burst (148 bit) 3 tail bits Uplink, UL time slot ( bit) ms Time/ms ComNets

17 Packet switching for Data Transmission Packet switching: The Data stream of the information source is segmented into Packets. Packets contain address of Sender and Receiver and user data. Ps are routed via radio and core network / Internet to the destination. Destination re-assembles the original information from the packets received Packet switching introduced 2001 as General Packet Radio Service (GPRS)* in GSM mobile radio network. Until 2001 GSM only supported channel switching. In GPRS packets of different mobile stations are multiplexted to a circuit-switched mobile TDMA channel to be transmitted via GSM. GPRS as the first made Internet mobile - worldwide. * B. Walke et. al.:cellpac - A Packet Radio Protocol Applied to the Cellular GSM Mobile Radio Network. Proc. 41th IEEE Vehicular Technology Conference, St. Louis, Missouri, USA, 05/1991, ComNets

18 GPRS Protocol Stack (Source: Fig. 4, B. Walke: Mobile Radio Networks 2002) 4 TCP/UDP Same functions in protocol stacks of adjacent systems communicate logically (horizontally) with each other. Data flow is vertically in protocol stacks. TCP/UDP 3 IP / X.25 CO end- to- end L3 virtual connec>on IP / X.25 CL IP SNDCP SNDP GTP GTP 2 LLC DLCI CO / CL LLC UDP/TCP UDP/TCP UDP/TCP RLC RLC / MAC Connec>on TBF CO RLC BSSGP BSSGP IP IP IP MAC MAC Network Service Network Service L2 L2 L2 1 GSM RF Radio Channel Phy GSM RF L1 bis L1 bis L1 L1 L1 Wire Wire MS BSS SGSN GGSN DTE Um Um = Radio interface Gb Gb, Gn = Interfaces between core network elements Gn TBF = Temporary Block Flow MS = Mobile Station SGSN/GGSN = Router CO / CL = Connection oriented / C-less BSS= Base Station Subsystem DTE= Data Terminal at fixed network ComNets

19 GPRS Logical Channels Group Channel Name Direction Function PCCCH PRACH Packet Random Access Channel UL random access PPCH Packet Paging Channel DL paging PAGCH Packet Access Grant Channel DL access grant PNCH Packet Notification Channel DL multicast PBCCH PBCCH Packet Broadcast Control Channel DL broadcast PTCH PDTCH Packet Data Traffic Channel UL/DL data PACCH Packet Associated Control Channel UL/DL assoc. Control ComNets

20 4G LTE System is a packet switched network with a 10ms-Periodic MAC Frame* Freq. Time Radio Frame (10 ms) 344 bit 344 bit 344 bit 344 bit 344 bit Semi-Persistent Scheduling (SPS) 344 bit 344 bit 144 bit (SID) 344 bit Source: Maciej Mühleisen 2015 Control Channels (CCHs) 12 Subcarriers Subframe (1 ms) Slot OFDMA Resource Element 20 ms CCH describes resource assignment in PDCCHs Physical * B. Walke et.al.: Wireless ATM: One Air-Interface Transport and Block Network (TB) Resource Protocols of the Mobile Broadband System, Block (PRB) (1 or more IEEE PRBs) Personal Communications Magazine, August 1996, Pair PDCCH: Physical Downlink Control Channel; SINR: Signal to Interference and Noise Ratio Maciej Mühleisen, ComNets 100 bit Header 344 bit 244 bit Number of PRBs depends on channel quality (SINR) at receiver 20/14

21 Content 1. Mobile Radio Networks and Services 2. Frequency Spectrum, Radio Propagation 3. Transmission Technology 4. Techniques for Increasing Capacity 5. Future (5G) Mobile Systems Architecture 6. Summary ComNets 21

22 Cell Capacity vs. Distance is Inverse to the Needs Radio range of base station limited by Pathloss & signal shadowing Max. permitted transmit power. è The more distant a terminal is from the base station, the smaller is the available capacity/m2 è The higher the radio frequency the larger the pathloss is: è # of base stations required increases Dramatically with frequency (CAPEX / OPEX) è Most user terminals are far away from the base station (close to cell border) Capcity/ Area Element Actual Available Capacity vs. Requested Capacity Available Needs: Number of UTs In distance d Cell border Requested by users è Interfercence by neighbor stations is highest at cell border. Location of the Base Station Distance d UT = User Terminal; CAPEX = Capital Expenditure; OPEX = Operational Expenditure; ComNets 22

23 Scattering of mm-waves under beam antenna B ut to n High angle of incidence due to multiple reflections fall outside of Rx beamwidth Tx reflections are relatively short due to narrow Tx beamwdith DL transmission reflections only result from obstacles located in the antenna beam. UL reflections by obstacles outside the beam miss the receiver ComNets

24 Smart Antenna for Space Division Multiple Access, SDMA Base Station uses antenna array to form beams (with side lobes) A signal is directed to user 1 and a Zero of antenna diagram is steered to user 2 (line diagram) At the same time another signal is directed to user 2 and a Zero is steered to user 1 (dashed diagr.) Multiple spatially separated user terminals are served in parallel Signal Amplitudenstärke eines beam forming Algorithmus mit zwei UTs ComNets 24

25 Data Rate under Multiple Input Multiple Output (MIMO) Signal Transmission Sector Cell Beam Forming (BF) Coordinated Beam Forming (CBF) Data Rate [bit/s/hz] Without beam forming (left: Sector cell) the pocket lamp effect is clearly visible Beam forming (middle) substantially increases data rate in whole cell sector. Co-ordinated beam forming requires co-operation of neighbored base stations. Data rate further increases. Benedikt Wolz, ComNets 25/12

26 Relay based multi-hop communication with self-backhauling of enbs Example: Strong shadowing Channel Group 1 Channel Group AP Source: ComNets 2003 Line of Sight Communication Networks, Aachen University (RWTH) 26

27 Optimally Placed Relays for Homogeneous Radio Coverage K. Sambale, B. Walke: DF-Relay positioning for maximum cell capacity. 18th European Wireless Conference, Poznan, Poland, April 2012, 1-6. Cell Small Cells Cell Radio Cells without Relays. Three optimally placed Relays per Sector (the area is served more homogeneous) Relays cells are Small Cells ComNets

28 Content 1. Mobile Radio Networks and Services 2. Frequency Spectrum, Radio Propagation 3. Transmission Technology 4. Techniques for Increasing Capacity 5. Future (5G) Mobile Systems Architectures 6. Summary ComNets 28

29 Mobile Internet and Internet of Things are major driving forces for 5G. In 2020: 1000 times greater capacity to connect 100B devices. 5G capabilities as defined by key performance target values: Peak data rate 10Gbps, Minimum guaranteed user data rate 100Mbps, Connection density 1M connections/ km2, Traffic density 10 Tbps/ km2, Radio latency 1 ms, E2E latency 10 ms for immersive and tactile user experience, Mobility up to 500 km/h To achieve this, higher efficiency is required, namely 5~15 times spectral, 100+ times energy, and 100+ times cost efficiency. ComNets

30 More Spectrum increases 5G Capacity much more than Cell Densifica:on ComNets

31 WLAN Mesh Network compe:ng to 4G System with WLAN off- loading Quelle: D. Castor (InterDigital): 5G mm- Wave, PIMRC, Sept ComNets

32 Mm-Wave supported 5 G System Massive MIMO transmission Heterogenes Mobilfunknetz aus 3GPP- System und mm- Wellen basiertem Mobilfunk für Hotspots basierend auf drei Technologien: Bleis>]- Beamforming, Vermaschung von Zugangspunkten (backhauling of BSs) und mobile Funkschni`stelle. Quelle: D. Castor (InterDigital): 5G mm- Wave, PIMRC, Sept ComNets

33 Ultra- dense Network mit self- backhauling and dynamic pencil beam control R. Baldemair, T. Irnich et.al.: Ultra- Dense Networks in mm- Wave Frequencies, IEEE Communica>ons Magazine, Jan. 2015, ComNets

34 Beam steering of mm-wave based Mobile Radio and Multi-hop first Proposed in 1985 B. Walke, R. Briechle: A local cellular radio network for digital voice and data transmission at 60GHz, Proc. Cellular & Mobile Communications International, London, Nov. 1985, Benedikt Wolz, ComNets 34/12

35 Digital Mobile Radio Systems Since 1989 available world-wide with standard radio interfaces. Every 10 years: - New generation of radio interface. - Improvement of user data rate by factor 10. Wireless and mobile radio dominate Internet Access: 6 Billion mobile terminals* but only 800 Million fixed Internet terminals. Key concepts originate from ComNets, RWTH Aachen, e.g.: * gsa.com; Packet switching (GPRS,1991**): mobile Internet access in 2G/3G/4G MAC-frame for radio resource management of LTE/WiMAX systems (1995) Multi-hop Relay 1999: better radio coverage / larger radio reach Small Cells for cell capacity improvement (2004). Dynamic Beamsteering in self-organizing Multi-hop Networks*** (1985) IEEE s (Mesh) und e (QoS Unterstützung) ( ). ** B. Walke: The Roots of GPRS - The first System for Mobile Packet based Global Internet Access. IEEE Wireless Communications, October 2013, *** B. Walke, R. Briechle: A local cellular radio network for digital voice and data transmission at 60GHz, Proc. Cellular & Mobile Communications International, London, Nov. 1985, ComNets

36 Danke für Ihre Aufmerksamkeit! Thank you for your time! ComNets

37 FFV-Workshop Bremen Panel Slide (B. Walke) Mobile communication enables a steady growth of new applications ( APPs ); A revolution of processes is expected for Humans through sensor / actuator networks Production / automation (Industrie 4.0), Healthcare / Judiciary system (law), Public service /administration, logistics, public traffic, etc. Mobile radio for everybody (GSM) exists since only 25 years Since 10 years we have mobile Internet access (GPRS / UMTS / LTE.) à Internet became omni-present 10 years ago. Internet is unsafe like the operating systems of computers connected Internet eases world-wide security attacks and non-prosecuted criminal actions All this will dramatically change culture and living style - more then TV did (1960) Are we prepared for this who is taking responsibility for this development? ComNets