Air Interface and Physical Layer techniques for 60 GHz WPANs

Transcription

1 Air Interface and Physical Layer techniques for 60 GHz WPANs (first author, presenter) Jimmy Nsenga Wim Van Thillo François Horlin Liesbet Van der Perre IMEC, Belgium SCVT 2006 Liège, November 2006

2 Standardization, applications, link budget The propagation 60 GHz Candidate modulation techniques Receivers Simulation results SCVT

3 Context: standardization and applications Multi-Gbit/s 60 GHz IEEE = High data rate WPAN IEEE c = PHY layer alternative for mm-wave SCVT

4 UM1 Uncompressed Video Streaming TV TV or Monitor U1/U3 Point-to-point PC, umpc, Set top Box (STB) SCVT

5 UM4 Conference Ad-hoc Computer (C2) U17 U16 Computer (C1) Wireless Bridge (WB) U17 U17 U16 U16 Computer (C0) U2 TV TV or Projector SCVT

6 UM5 Kiosk File-downloading U7/U9 U7/U9 STB, Game Consol Movie and Game Kiosk Mobile Storage Device, PDA SCVT

7 c Standard Timeline (1) 09/06 (Melbourne, Aus.) - Continued channel model discussions. Continued development of UMD. Future plan: 11/06 (Dallas TX) Finalize channel model. Finalize channel model document. Finalize UMD document. Finalize Technical Last Requirements. Issue CFP. Continue MAC discussions and make week! recommendation for MAC development. 01/07 (London, UK) Presentation of preliminary proposals. 03/07 (Orlando, FL) Final proposals due 1 week prior to meeting. Presentation of all proposals. 05/07 (Montreal, CA) Present updated/merged proposals. Down selection begins. If down-selection finishes, begin drafting Standard. SCVT

8 c Standard Timeline (2) 07/07 First letter ballot 09/07 Re-circulation 11/ Sponsor ballot 01/ Sponsor re-circulation 03/08 Standard finished. SCVT

9 Why 60 GHz? Lots of unlicensed BW GHz USA Canada Korea 40 dbm EIRP 40 dbm EIRP 10 dbm, EIRP TBD Japan 10 dbm, 57 dbm EIRP Australia Europe? Min 2500 MHz, 40 dbm EIRP SCVT

10 Antenna gain boosts difficult link budget Frequency 60 GHz 60 GHz Carrier frequency bandwidth Tx Tx power Tx antenna gain Channel distance LOS loss Oxygen attenuation Rx antenna gain Thermal noise Rx Noise figure Other RX losses coding rate coding gain processing gain SNR and Margins SNR QPSK (BER = 1e-5) margin QPSK Bit rates Overhead raw spectral efficiency (QPSK) Net bit rate (QPSK) BER BER Performance of QPSK and QAM16 in AWGN QPSK QAM16 QAM SNR = log 2 (M)*E B /N 0 (db) SCVT

11 The 60 GHz Channel Source for the channel measurements: [doc. IEEE c, Denver, March 2006] SCVT

12 Measurement scenarios plan (IMST) LOS NLOS Edge SCVT

13 Direction of Arrival vs. Time of Arrival (LOS scenario, horn antenna) 100 medn0054 ezl los t501 h01 = Delay, [ns] PDP [db] Multipath components are largely attenuated by directional antenna SCVT

14 Direction of Arrival vs. Time of Arrival (LOS scenario, biconical antenna) -60 medn0090 c zm los t501 b01 = PDP [db] -90 K ~ 15 db -100 K ~ 7 db -110 K < -50 db -120 Several strongly localized rays in time/angular dimensions for delays < 50 ns and angles < Delay, [ns] Strong multipath components may have Rician distribution or may be almost deterministic with random phases SCVT

15 Direction of arrival vs. Time of arrival (NLOS scenario, horn antenna) Broadening of direction of arrival angles due to scattering during the propagation of waves through the books -70 medn0059 dyi nlos t501 h01 = Magnitude [db] angle [deg] SCVT

16 DoA for Different Delays medn0091 cym los t501 b01 = delay-24 [ns] 0.08 medn0091 cym los t501 b01 = delay-34 [ns] angle [deg] angle [deg] 0.04 medn0091 cym los t501 b01 = delay-14 [ns] 0.07 medn0091 cym los t501 b01 = delay-9 [ns] medn0091 cym los t501 b01 = delay-6 [ns] angle [deg] angle [deg] angle [deg] SCVT

17 Modulation technique SCVT

18 PHY Layer Requirements Data rate: 2 Gbps mandatory 3 Gbps optional Physical bandwidth: 4 channels in 7 GHz: 7/4 = 1.75 GHz ~1.5 GHz? 3 channels in 7 GHz: 7/3 = 2.33 GHz ~2.0 GHz? Spectral efficiency (uncoded): 2 Gbps 2 x (4/3) / 1.5 = 1.78 b/s/hz 2 x (4/3) / 2.0 = 1.33 b/s/hz 3 Gbps 3 x (4/3) / 1.5 = 2.66 b/s/hz 3 x (4/3) / 2.0 = 2.00 b/s/hz 3 channels option relaxes spectral efficiency requirements. SCVT

19 System level approach Battery-powered PA is key consumer Simplify filtering Low spectral regrowth LOS & NLOS Possible Simplify equalization Avoid OFDM Avoid M-QAM Add CP for freq. domain equalizer PSK-based: CP-OQPSK CPM-based: CPM or CP-CPM (many flavours) SCVT

20 Achieving required bit rates with CP-M-PSK Q Q Q I I I QPSK O-QPSK 3π/8-8PSK 1.75 GHz 2.33 GHz 2 Gbps 1.78 b/s/hz CP-OQPSK 1.33 b/s/hz CP-OQPSK 3 Gbps 2.66 b/s/hz CP-3π/8-8PSK 2.00 b/s/hz CP-OQPSK SCVT

21 CPM modulation parameters log 2 M bits/symbol [Anderson, Digital Phase Modulation, 1986, Springer (Plenum Press)] Pulse shape and length (rect, raised cos, gaussian, ) SCVT

22 Achieving spectral efficiency with CPM 3COS,M=4,h=0.25 Good spectral performance 3COS,M=2,h=0.5 Low complexity 3COS,M=4,h=0.5 Good error performance SCVT

23 Achieving required bit rates with CP-CPM Q Q Q I I I QPSK CPM h=0.5 CPM h= Gbps 2 Gbps 3 Gbps 1.75 GHz 0.89 b/s/hz 3COS, M=2, h= b/s/hz 3COS, M=4, h= b/s/hz?? 2.33 GHz 0.67 b/s/hz 3COS, M=2, h= b/s/hz 3COS, M=4, h= b/s/hz 3COS, M=4, h=0.25 SCVT

24 Transceiver Architecture SCVT

25 Transceiver architecture & non-idealities Phase noise ADC clipping & resolution SCVT

26 Receivers SCVT

27 PHY Layer (CP-OQPSK) TX RX with integer sampling To FDE and symbol detection RX with fractional sampling To FDE and symbol detection SCVT

28 PHY Layer (CP-OQPSK) System model with real and imag. input + fractional sampling Fractional sampling only MMSE solution (complex!) Low complexity MMSE solution exploiting circulant structure and permutation matrices SCVT

29 CPM parameters reminder log 2 M bits/symbol [Anderson, Digital Phase Modulation, 1986, Springer (Plenum Press)] Pulse shape and length (rect, raised cos, gaussian, ) SCVT

30 Any CPM signal can be decomposed in a sum of linearly modulated pulses The Laurent decomposition: Pseudocoefficients Laurent functions amplitude C 0 > 99% of energy C 2 C 1 C time [T] SCVT

31 We construct a reduced-complexity receiver by discarding pulses with little energy Optimal, highly complex receiver 1 st Laurent function (greatly) reduced complexity receiver SCVT

32 CPM receiver for multipath Time-domain equalizer Matched filter for strongest Laurent pulse SCVT

33 Simulation results SCVT

34 Simulation parameters CP-OQPSK Channel parameters (Saleh- Valenzuela) CPM SCVT

35 Performance in multipath O-QPSK CPM SCVT

36 Performance in multipath, with phase noise O-QPSK CPM (common phase rotation over block is removed) SCVT

37 Performance in multipath, with ADC resolution O-QPSK CPM (ideal AGC, ideal choice of clipping level) SCVT

38 Conclusion 60 GHz band offers huge bandwidth and big challenges CP-OQPSK and CPM are low PAPR modulations CP-OQPSK features easy (optional) FDE Integrated Phase noise requirement CP-OQPSK: ~-20 dbc CPM: ~-16dBc ADC resolution requirement CP-OQPSK: ~5-6 bits CPM: ~5 bits SCVT

39 SCVT