URSI-GA2005 2005/10/24, New Delhi, India Double Directional Cluster Properties Investigated from a Series of Ultra Wideband Propagation Measurements in Home Environments Katsuyuki Haneda, Jun-ichi Takada UWB Technology Institute, National Institute of Information and Communication Technology / Tokyo Institute of Technology Takehiko Kobayashi UWB Technology Institute, National Institute of Information and Communication Technology / Tokyo Denki University
Table of contents • Aim of this study • Measurement environments • Analyses of measured data • Channel parameters • Physical interpretation of the parameters • Summary • Acknowledgement
Aim of this study • The double-directional UWB measurement enables us to develop propagation models which are: – Applicable both for MIMO and UWB systems – Antenna-independent – Quite high resolution using UWB signal – Available over wide frequency range of UWB
UWB sounding system • Vector Network Analyzer & spatial scanner Tx side Rx side UWB Synthetic antenna array • 3-D (x-y-z) scanner and UWB antenna Preamp (30dB) VNA • Omni-directional monopole antenna GPIB • flat group delay characteristics PC • frequency • Data acquisition sweeping from • Measurement control 3.1 to 10.6 GHz via GPIB
Measurement environments • In a Japanese wooden house, total of 7 channels were measured: 1. LOS room 2. OLOS Room-corridor 3. NLOS Room-corridor 4. NLOS Inter-room 5. NLOS Inter-floor 6. OLOS Indoor-outdoor 7. NLOS Indoor-outdoor
Measurement environments • First floor
Measurement environments • Second floor
Specifications of the experiment • Frequency range: 3.1 to 10.6 GHz • Array shape – Virtual array, 4 x 4 squared shape URA in horizontal plane (Rx), – 4 elements ULA (Tx) – 48mm element spacing • Antennas at Tx and Rx – UWB monopole antennas – Fluctuation of group delay characteristics is less than 0.1 ns in the considered bandwidth • Receiving SNR: at least 20 dB • Calibration: function of VNA, back-to-back
Analyses on measured data (1/3) 1. Path extraction (parameters estimation) – SAGE algorithm for UWB signal – Antenna deconvolution – Residual components: diffuse components 2. Clusterization of the paths – In double-directional manner, i.e., in DOD-DOA- TOA domain – With a heuristic approach – Cluster: group of paths with the similar parameters 3. Analyses of clusters – We introduced channel parameters to grasp channel behavior intuitively
Example of power spectrum (1/2) • Original spectrum and estimated components by the SAGE Red: Spectrum of measured data Green: Detected paths by the SAGE
Example of power spectrum (1/2) • Residual spectrum after the extraction of 100 waves Red: Residual spectrum
Diffuse components -95 dB -100 dB -105 dB -110 dB
Channel parameters (1/5) 1. Number of clusters N cluster 2. Number of paths in each cluster N path 3. Standard deviation of the path distribution σ σ within clusters w.r.t. azimuth and delay τ φ 4. Cluster power ratio K cluster → Power ratio between the strongest cluster and other clusters (in case of LOS, strongest cluster is replaced by LOS path) 5. Percentage of the sum of extracted power by paths PCT 6. Dynamic range of paths over diffuse (residual) components P dyn
Channel parameters (2/5) 1. The num. of clusters / the num. of paths in each cluster N N path cluster 7 3 ~ 13 LOS room 8 3 ~ 19 OLOS room-corridor 8 2 ~ 20 NLOS room-corridor 8 2 ~ 23 NLOS inter-room 9 3 ~ 14 NLOS inter-floor 6 2 ~ 14 OLOS indoor-outdoor 6 3 ~ 18 NLOS indoor-outdoor
Physical interpretation (1/3) • Reinforcing inside the ceiling causes diffraction
Physical interpretation (3/3) • Result of cluster extraction
Channel parameters (3/5) 2. Standard deviation of paths in azimuth / delay domains σ σ [deg] [ns] φ τ 0.7 ~ 6.3 0.06 ~ 1.41 LOS room 3.0 ~ 10.8 0.61 ~ 1.88 OLOS room-corridor 0.9 ~ 9.3 0.50 ~ 1.79 NLOS room-corridor 0.3 ~ 11.9 0.15 ~ 1.28 NLOS inter-room 1.2 ~ 13.1 0.28 ~ 1.90 NLOS inter-floor 0.7 ~ 10.5 0.11 ~ 1.83 OLOS indoor-outdoor 0.9 ~ 6.4 0.11 ~ 1.85 NLOS indoor-outdoor
Channel parameters (4/5) 3. Cluster power ratio and extracted power by paths K [dB] [%] PCT cluster − 77.0 LOS room 2.1 − 51.0 OLOS room-corridor 4.8 − 52.9 NLOS room-corridor 4.3 − 71.8 NLOS inter-room 1.2 − 58.8 NLOS inter-floor 5.4 9.6 72.3 OLOS indoor-outdoor 7.4 77.5 NLOS indoor-outdoor
Physical interpretation (2/3) • Indoor-outdoor meas. Tx Metal shutter Rx
Channel parameters (5/5) 4. Dynamic range of paths over diffuse components [dB] [%] P PCT dyn 29.2 77.0 LOS room 24.0 51.0 OLOS room-corridor 25.5 52.9 NLOS room-corridor 30.5 71.8 NLOS inter-room 21.6 58.8 NLOS inter-floor 31.6 72.3 OLOS indoor-outdoor 34.0 77.5 NLOS indoor-outdoor
Physical interpretation (3/3) • Indoor-outdoor scenarios – The strongest cluster carries most of the propagating power – Large and P , K PCT dyn cluster • LOS scenario – Contribution of power from scattered paths is large due to effective illumination of scattering objects by Tx and Rx – Large and (but small ) P K PCT dyn cluster • NLOS (OLOS) scenarios – Channels are diffuse in which huge number of weak paths aggregate – Small and , P K PCT dyn cluster
Summary • Deterministic measurement and characterization of propagation channels in a wooden house for UWB / MIMO indoor applications – Cluster analyses of paths – Introduction of channel parameters and its derivation – Physical interpretation of the parameters • Future works – Constructing channel models – Evaluation of antenna effects for MIMO and UWB systems – Measurements in other environments
Acknowledgement • The authors would like to thank the members of NICT UWB Consortium and UWB Technology Institute in NICT: – Prof. Dr. Kiyomichi – Dr. Makoto Yoshikawa Araki – Dr. Akira Akeyama – Mr. Iwao Nishiyama – Dr. Osamu Sasaki – Dr. Honggang Zhang – Dr. Yuko Rikuta – Mr. Fumio Ohkubo – Mr. Takahiro Miyamoto
Analyses on measured data (2/3) • Cluster extraction?
Double-directional UWB meas. • Double-directional measurement enables us to separate antenna effects from channel model (M. Steinbauer et., al, 2001) DOD DOA Tx Rx Propagation Antenna + Propagation = Channel
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