Project: IEEE P Working Group for Wireless Personal Area Networks N

Transcription

1 Project: IEEE P Working Group for Wireless Personal Area Networks N (WPANs( WPANs) Title: [Draft PHY Proposal for 60 GHz WPAN] Date Submitted: [11 November, 2005] Source: [Eckhard Grass, Maxim Piz, Frank Herzel, Rolf Kraemer] Company [IHP] Address [Im Technologiepark, Frankfurt (Oder), D-15236, Germany] Voice:[ ], FAX: [ ], [grass@ihp-microelectronics.com] Re: [] Abstract: [Based on a simple channel model and link budget calculations, some PHY parameters for a 60 GHz OFDM WPAN are derived. The proposed PHY parameters support data rates up to 1 GBit/s and can be extended to 2 Gbit/s.] Purpose: [This document is intended to serve as a basis for discussions for defining the IEEE c PHY parameters. Implementation aspects of 60 GHz RF circuits are presented] Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P Slide 1

2 Draft PHY Proposal for 60 GHz WPAN Eckhard Grass, Maxim Piz, Frank Herzel and Rolf Kraemer (IHP) Slide 2

3 Outline Introduction and application scenario Linkbudget and phase noise calculation Proposed PHY parameters for 60 GHz OFDM WPAN Integrated receiver frontend for OFDM demonstrator in SiGe BiCMOS technology Conclusions Acknowledgements Slide 3

4 Goals Definition and development of suitable algorithms and implementation of a 60 GHz, 1 Gbit/s WLAN demonstrator including Highly integrated analog frontend (AFE) OFDM baseband processor (BB) Medium Access Control Processor (MAC) Features: 60 GHz frequency band >= 1 Gbit/s net transmission rate High spectral efficiency (> 2.5 Bit/s/Hz) Low cost (Si-based circuits) Demonstrator flexibility (standard interfaces, FPGA, µ Controler) Protocol with QoS support Slide 4

5 60 GHz WPAN Application Scenario Indoor home and office scenario (Wireless Gbit Ethernet) Fast video download (Wireless USB-Stick) Media supply in public areas (trains, busses, etc.) AP AP Slide 5

6 Simplified Link Budget Calculation Assumptions: SNRmin = 20 db for 16-QAM-1/2 (source rate = 480 Mbit/s, implementation loss = 2 db + 1 db (phase noise degradation)) Receiver noise figure: NF = 10 db Transmit power: Ps = 10 dbm (P1dB = 16 dbm, Backoff = 6 db) Use of Vivaldi Antennas with GTX = GRX = 7 db (3 db misalignment) Sensitivity: S = dbm / Hz + 10 log (320MHz) + NF + SNR = 59dBm min Maximum range for 16-QAM-1/2: D = Ps + G + G S = 10dB + 14dB + 59dB 83dB max 1 2 = L max Dmax / 20 = 10 λc /(4π ) 5,5meters Slide 6

7 Small-Scale Channel Measurement Underlying setup and parameters Correlation channel sounding (multitone) RF center Measurement BW Postprocessing 60 GHz 1 GHz - digital complex down conv. - noise filtering - mapped example: Hann window in frequency domain Measurement scenario and parameters 100 snapshots in small office duration of 1 snapsh. temp. dist. of snapsh. moving distance 26 µs 10 ms 3 cm Slide 7 FhG-HHI-Berlin

8 Small-Scale PDPs, TOA Parameters 10 Averaged PDP, LOS, 1 m 10 Averaged PDP, LOS, 2 m 0 0 Normalized Power [db] Normalized Power [db] Excess Delay [ns] LOS TOA Parameters [ns] (relative threshold: -25 db) d 1 m 2 m 3 m τ max 20,7 25,7 37,5 τ m 3,08 5,18 4,99 τ rms 3,31 4,47 5,65 Slide 8 Normalized Power [db] Excess Delay [ns] Averaged PDP, LOS, 3 m Excess Delay [ns]

9 Delay Spread Delay spread measurements done by Akeyama, NTT for c: Study on mm wave propagation characteristics to realize WPAN (for antennas with directivity in office scenario) => Delay spread less than 20 ns => Guard interval of 160 ns sufficient LOS NLOS Slide 9

10 RMS phase error (degree) Phase Noise Modeling and Effects Simulation of uncoded 16-QAM OFDM system with 192 data sub-carriers, 16 pilot sub-carriers CPE correction included Results: Optimum bandwidth depends on crystal phase noise < 3 degree rms phase error required for low BER (16-QAM) RMS phase error after CPE correction, simulated ζ=0.5, L VCO solid: second-order model dashed: first-order model L 100 khz= -120 dbc/hz -130 dbc/hz -140 dbc/hz log [BER] loop bandwidth [MHz] Slide ζ=0.5, L VCO solid: second-order model dashed: first-order model L 100 khz= -120 dbc/hz -130 dbc/hz -140 dbc/hz loop bandwidth [MHz]

11 OFDM Symbol Length Bandwidth tradeoff between reference noise and VCO noise Low bandwidth ( khz) desirable to suppress filter noise and charge pump noise Short symbols (<1µs) mandatory for rms phase error below 3 degree RMS phase error after correction of common phase error as a function of PLL bandwidth for three symbol lengths. Slide 11

12 Proposed PHY Parameters and Data Rates Service bandwidth 1-2 GHz (2-4 frequency channels) Modulation Coding rate Data rate Channel bandwidth (channel spacing) B = 500 MHz BPSK (m=1) ½ 120 Mbit/s FFT bandwidth BFFT = 400 MHz BPSK ¾ 180 Mbit/s Number of subcarriers N=256 QPSK (m=2) ½ 240 Mbit/s Subcarrier spacing F = 400 MHz/256 = MHz QPSK ¾ 360 Mbit/s Guard time FFT period Symbol duration Modulation Channel coding, rates Tg = 160 ns, (120, 240 ns optional) TFFT = 640 ns Ts = = 800 ns BPSK, 4, 16, 64-QAM Convolutional, r = ½, 2/3, ¾ (LDPC in future) 16-QAM (m=4) 16-QAM 64-QAM (m=6) 64-QAM ½ ¾ 2/3 ¾ 480 Mbit/s 720 Mbit/s 960 Mbit/s 1080 Mbit/s Target distance of air link Data subcarriers Pilot subcarriers Zero gap 5-10 meter Nd = 192 Np = 16 Nz = 5 Turbo mode with doubled subcarrier spacing possible => data rates up to 2 Gbit/s Slide 12

13 Pilot, Data and Zero Subcarriers Modulation bandwidth = 320 MHz Number of data subcarriers = 192 Number of pilot subcarriers = 16 Symbol time = 800 ns Guard time = 160 ns = 1/5 symbol time Subcarrier spacing = MHz Slide 13

14 Allocation of Bandwidth to User Groups Three main frequency sub-bands: 57 GHz 58 GHz 61 GHz 63 GHz 64 GHz End User, Fixed Networks, Emergency 57 GHz Allocated to end user (Commodity products, Mobile,...) Allocated to fixed installations (Wire replacement, Train, Bus...) Emergency (like 11.p) 64 GHz 4 GHz 8x500 MHz channels 2 GHz 4x500 MHz channels 1 GHz 2x500 MHz channels Slide 14

15 60 GHz LNA and Mixer in SiGe BiCMOS 60 GHz RF Frontend Results: Chip area: 1.1 mm x 0.8 mm 1 db compression point: -1.6 dbm (out) Conversion gain: 28 db In-band gain ripple (57-64 GHz): < 1 db IF output (dbm) IF=5 GHz 1 db compression point 1.6 dbm RF input (dbm) Conversion gain (db) RF VCC1 VCC2 LO Frequency (GHz) IF Slide 15

16 60 GHz Receiver Frontend (in Fabrication) High-Speed SiGe:C BiCMOS Technology f t /f max = 200 GHz Down-converter (LNA + mixer) and frequency synthesizer on one chip RF GHz 56 GHz PLL IF 5.25 GHz Area < 2mm 2 Crystal 109 MHz Slide 16

17 Receiver Board Layout Board material: Rogers 3003 (5 mil) on FR4 Chip connection: Ribbon bonding / wire bonding On-board antenna: Single-ended, Vivaldi type, Microstrip connection 60 GHz RX Chip MHz (56 GHz/512) Vivaldi Antenna Crystal reference Slide 17 IFn IFp

18 Conclusions 60 GHz systems can support massive data rates; 7 GHz of unlicensed bandwidth available Oxygen attenuation and attenuation through walls facilitates efficient frequency re-use Creating multiple data streams using MIMO techniques is not a useful option; However, beamforming can significantly improve the linkbudget SiGe BiCMOS efficient technology for 60 GHz band 60 GHz frequency synthesizer and RF receiver frontend (LNA + Mixer) were successfully implemented in SiGe BiCMOS technology and tested A complete transceiver was designed and is being fabricated Small wavelength allows on-chip antenna and small form factor Slide 18

19 Acknowledgements BMBF (Federal Ministry of Education and Research Germany) for funding the WIGWAM Project ( WIGWAM Team at IHP: Jean-Pierre Ebert, Klaus Schmalz, Yaoming Sun, Srdjan Glisic, Milos Krstic, Klaus Tittelbach, Wolfgang Winkler WIGWAM IHP Subcontractors: Karin Schuler, Werner Wiesbeck (Uni Karlsruhe), Wilhelm Keusgen, Michael Peter (FhG-HHI Berlin) WIGWAM Consortium - in Particular Project Coordinators: Gerhard Fettweis, Ralf Irmer and Peter Zillmann (TU Dresden) ( Slide 19