Channel Models, Regulation and

Transcription

1 Technische Universität Carolo-Wilhelmina zu Braunschweig tubs.city Jahrestagung g 2009 Towards Wireless Multi-Gigabit Systems Channel Models, Regulation and Standardisation Thomas Kürner

2 Towards Wireless Multi-Gigabit Systems Content Terahertz Communications Lab Motivation Channel Models for 60 GHz Systems Propagation conditions beyond 100 GHz - Free space path loss, diffraction, transmission - Reflection and scattering - A simple two-ray model Regulation and Standardisation Challenges and future work 2/37

3 Terahertz Communications Lab (TCL) TCL consists of five research Braunschweig Mobile Radio Systems Terahertz Systems VLSI Design German Institute Microwave Engineering of Standards (PTB) 3/37

4 Motivation Edholm s Law of data rates Source: IEEE Spectrum, Juli /37

5 Motivation What are potential Applications for Multi-Gigabit Radio Systems? WLANs WPANs HDD Point-to-point links, e.g. hard-drive to computer, camera to computer Wireless extension of Ethernet and GigabitEthernet LANs Kiosk downloading 5/37

6 Motivation Frequency Bands for Multigigabit Systems Commerically available systems - currently data up , 5.2 GHz - Several 100 Mbps with IEEE802.11n Systems currently under development, which have caused significant interest in industry - upcoming GHz and GHz Future systems currently considered in research, partly with first demonstrators in laboratory - ~ GHz (NTT Docomo) - Towards 100 THz frequencies ( GHz) 6/37

7 Channel Modeling at 60 GHz Building a Wireless HDMI at 60 GHz Beamforming required for seamless service Propagation Channel must be well understood in realistic environments Application of measurements and ray- tracing to derive statistical channel models 7/37

8 Channel Modeling at 60 GHz Measurements and Modeling of Angle-of-Arrival and Angle-of-Departure Rx Tx Direct path First Order Reflections Second Order Reflections 8/37

9 Channel Modeling at 60 GHz Measurement of Signal Variations caused by a Person stepping into the direct Ray 9/37

10 Channel Modeling at 60 GHz Generating Statistical Models an Example from Ray- Tracing in an Empty Room Scenario 5 m Rx T x 10/37

11 Propagation Conditions beyond 100 GHz Free Space Loss and Atmospheric Attenuation Distance / m Frequency /GHz High gain antennas are required Atmospheric attenuation can be neglected in indoor environments 11/37

12 Propagation Conditions beyond 100 GHz 300 GHz Transmission System 4 m -94 db 12/37

13 Propagation Conditions beyond 100 GHz 300 GHz Transmission System UHF FBAS-Signal FBAS-Signal UHF 855 ± 6 MHz 855 ± 6 MHz -40 dbm VHS-Rek. DVD-Player TV-Karte d = 10 m G Verstärker = 37,5 db F Verstärker = 7,1 db L att = 10 db L M = 9,7 db T M = 960 K G Ant = 26 db G L1 = 14 db G L2 = 14 db G Ant = 26 db L M = 9,7 db T M = 980 K L ZF-Misch = 8,3 db T ZF-Misch = 700 K ± 6 MHz Mini circuits VDI VDI VDI VDI ANZAC ZHL-42W WR2.8SHM Diagonalhorn PE-Linsen Diagonalhorn WR2.8SHM MDC-166 (WR2.8) (WR2.8) Jastrow, C., Münter, K., Piesiewicz, R., Kürner, T., Koch, M., Kleine-Ostmann, T., 300 GHz transmission system, IEE Electronics Letters, Vol. 44, No. 3, January 2008, pp /37

14 Propagation Conditions beyond 100 GHz more details on the mixer a) DPRO ~ am plifier and tripler GHz WR6.5x3 150 GHz x 3 tripler ~ crystal oscillator monitor port 50 term ination 0 10 GHz < 0.5 mw signal generator 290 GHz 310 GHz 50 µw b) DPRO ~ am plifier and tripler GHz W R6.5x GHz x 3 tripler ~ crystal oscillator monitor port 50 term ination spectrum analyser 5 15 GHz 290 GHz 310 GHz 14/37

15 Propagation Conditions beyond 100 GHz Transmitter Phasengeregelter DRO (16,67 GHz) Referenzquartz (10 MHz) Verstärker / Verdreifacher (50 GHz) Monitorport & Vorverstärker Verdreifacher (150 GHz) Oberwellenmischer (300 GHz) 15/37

16 Propagation Conditions beyond 100 GHz Received signal without lense antennas 10 cm 50 cm 30 cm 80 cm 16/37

17 Propagation Conditions beyond 100 GHz Received signal with lense antennas 10 m 21,5 m 15 m Reflection on painted wall (4m) 17/37

18 Propagation Conditions beyond 100 GHz Transmission, Diffraction and Reflection/Scattering attenuation is high enough to neglect transmission as a relevant propagation mechanism in indoor environments at THz frequencies diffraction does not constitute a relevant propagation mechanism already at mm-waves Reflection and scattering is the only relevant mechanism 18/37

19 Propagation Conditions beyond 100 GHz An experiment using the 300 GHz system Tx Rx 19/37

20 Propagation Conditions beyond 100 GHz An experiment using the 300 GHz system 20/37

21 Propagation Conditions beyond 100 GHz Modelling the Indoor Propagation Channel As at 60 GHz Ray-tracing is well-suited to model the propagation channel beyond 100 GHz in indoor environments Proper modelling of reflection and scattering processes for typical building materials required: - Reflection on smooth surface - Scattering on rough surface - Reflection on multi-layer objects 21/37

22 Reflection Measurements and Modeling Rough Surface Scattering in Specular Direction Scattering on Rough Surfaces plaster Raufaser wallpaper 22/37

23 Reflection Measurements and Modeling Rough Surface Scattering in Specular Direction 1 Raufaser, Grad, TE Polarization Raufaser, 70 Grad, TE Polarization Measured Surface Properties of Raufaser Re elative Häufigkeit Oberflächenhöhe [mm] Raufaser Reflexionsfa aktor Reflexionsfakt tor f [GHz] f [GHz] 23/37

24 Reflection Measurements and Modeling Bistatic reflection coefficient for double glass as a function of incidence angle and frequency 24/37

25 Reflection Measurements and Modeling Multiple Layer Modelling Calculation of reflection and transmission coefficients by transfer matrix method Magnitude of reflection coefficient: white paint on plaster 25/37

26 Two-Ray-Modeling at 300 GHz Measurement set-up 26/37

27 Two-Ray-Modeling at 300 GHz Comparing Measurements with the Model 27/37

28 System simulations Influence of wall materials Maximum achievable data rates for different for wall materials form link level simulation Plastic mirrors Smooth plaster ( =0 mm) empty room scenario assuming all walls are covered by the same material BPSK modulation once-reflected paths rough plaster ( =0,05 mm) very rough plaster ( =0,15 mm) 28/37

29 Regulation and Standardisation Availability of additional frequency bands Microwave range? 3 GHz 30 GHz mm-wave range? 30 GHz 300 GHz US frequency allocations, Oct 2003 Potential at 300 GHz and beyond! Currently unregulated spectrum at THz frequencies (300 GHz- 3 THz) available but this spectrum is on the agenda for WRC 2011 (agenda item 1.6)! 29/37

30 Regulation and Standardisation Spectrum issues Frequency band beyond 275 GHz is on the agenda for WRC 2011 Agenda item 1.6. covers passive services (Radio astronomy, Passive Remote Sensing, Aeronomy) Agenda item 1.6 will most probably modify Footnote Footnote 5.565: 565: which currently reads The frequency band GHz may be used by administrations for experimentation with, and development of, various active and passive services... yielding a more detailed specification of the operational conditions of the passive services. Stakeholders of active services have to take care that the active service is not removed in the footnote t 30/37

31 Regulation and Standardisation Spectrum issues CEPT and German adminstration are currently supporting the idea of keeping the active services in the footnote: - CEPT recognizes that an identification of possible use of certain bands for passive services should not automatically preclude future consideration of these bands for active services... Source: PT B(08)058 Annex 3draft CEPT Brief on WRC-11 Agenda item 1.6 (bands above 275 GHz); For the future interference studies between active and passive services may be required 31/37

32 Regulation and Standardisation Standardisation A couple of different standards have been already developed or are under development for the 60 GHz bands: IEEE c ECMA-387 WirelessHD IEEE TGad For 300 GHz and beyond IEEE has established a THz Interest Group 32/37

33 Regulation and Standardisation IEEE 802 IEEE Task Group ad Preparing a WLAN for very high throughput (beyond 1 Gbps) operating at 60 GHz compatible to IEEE family Study Group has been elevated to a Task Group in January 2009 Currently documents describing evaluation methodology and channel models are developed Involvement of TUBS IEEE THz Interest est Group - Survey of technological developments - Channel modeling - Spectrum Issues (WRC 2011, agenda itrem 1.6) - Involvement of TUBS 33/37

34 Challenges and future work Research: Propagation, Channel Characterisation and System Simulation Verification of complete ray-tracing model Measurements and modelling of rough surface scattering in non-specular directions Modelling of rough surfaces on multiple layers In-depth channel characterisation both by measurements and simulaton - Enabling system simulations i - Development of system architectures (antenna concepts, transmission systems low complexity!?) 34/37

35 Challenges and future work Research: Technological Challenges Development and characterisation of components Emitter Receiver Amplifier Antennas Feeding of the antennas Mixer 35/37

36 Challenges and future work An Interdisciplinary approach is required! Investigating g channel characteristics at 300 GHz (measurement techniques!) Antenna concepts to overcome the high attenuation at 300 GHz and beyond Defining the radio transmission system (modulation, coding, MAC) Building an integrated RF front end Connecting to the backbone network 36/37

37 Towards Wireless Multi-Gigabit Systems Further Reading Piesiewicz, R., Kleine-Ostmann, T., Krumbholz, N., Mittleman, D., Koch, M., Schoebel, J., Kürner, T., Short-Range Ultra Broadband Terahertz Communications: Concept and Perspectives, IEEE Antennas and Propagation Magazine, Vol. 49, No. 6, December 2007, pp Piesiewicz, R., Jansen, C., Mittleman, D., Kleine-Ostmann, T., Koch, M., Kürner, T., Scattering analysis for the modeling of THz communication systems, IEEE Transactions on Antennas and Propagation, Vol. 55, No. 11, Part 1, November 2007, pp Jansen, C., Piesiewicz, R., Mittleman, D., Kürner, T., Koch, M., The impact of reflections from stratified building materials on the wave propagation in future indoor terahertz communication systems, IEEE Trans. on Ant. and Prop., Vo. 50, No. 5, May 2008, pp Kürner, Th., Jacob, M., Application of Ray Tracing to Derive Channel Models for Future Multi-Gigabit Systems. accepted for publication in Proceedings of International Conference on Electromagnetics in Advanced Applications, Torino /37

38 Towards Wireless Multi-Gigabit Systems Thank you for your attention