A reciprocal MIMO-UWB Radio Channel Deterministic Modeling Framework CROWNCOM - 2006 Mykonos June 10

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A reciprocal MIMO-UWB Radio Channel
Deterministic Modeling FrameworkCROWNCOM -
2006Mykonos June 10

• B. Uguen,L.-M. Aubert, F. Tchoffo Talom,
• bernard.uguen_at_insa-rennes.fr

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OUTLINE

• Interest of site-specific transmission channel
  simulation
• Description of the proposed formalism
• SISO case
• MIMO case
• Antenna plug in
• Emphasis on channel reciprocity
• Illustrations from the simulation tool
• Effect of antennas on the UWB transmission
  channel
• 2X2 MIMO situation
• Conclusion

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UWB application context

• Short range High data rate systems (OFDM,
  DS-CDMA)
• WPAN
• Low data rate systems with location capabilities
• Sensor networks

? Indoor propagation is the most common situation
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Interest of site-specific channel simulation
Site-specific channel simulation can be
advantageously used to

• Evaluate channel characteristics in site-specific
  situation
• Study the effect of antennas on the transmission
  channel
• Evaluate location capabilities of a radio network
  in a given environment
• Study the spatial structure of the channel
• Build heterogeneous radio scenario
• Evaluate time reversal focusing techniques

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Ray tracing techniques for propagation channel
simulation

• RT techniques approach radio propagation
  through a finite number of rays
• Upon each ray are encountered localized
  interactions with obstacles which separate Tx
  from Rx as diffraction, reflection, double
  refraction (wall, doors, windows,)
• The ray cluster that is obtained is conditioned
  by the geometry of the floor and by constitutive
  properties of building materials.
• The E.M field is constructed using GO/UTD
  techniques.

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The matrix propagation channel
a Tx b Rx k ray l interaction
Stored for each ray
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The propagation channel (without antennas)
Indoor 3D Ray tracing 3D
Matrix channel in the time domain
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Exhaustive vectorial description of antennas
The vectorial knowledge of antenna (antenna
array) radiation can be obtained

• Closed form analytical expressions (few simple
  antennas)
• Electromagnetic simulation (HFSS, CST, )
• Near-field measurements

Unitary property
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Wideband measurements in a near-field chamber
Near Field chamber Satimo Stargate 32 (0.8-6GHz)
Electric field polarization ellipse in the far
field Antenna CMA-118A (f 3 GHz)
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Introducing the antenna into the channel model
Scalar ray transfer function
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SISO static transmission channel
Transmission channel reciprocity
Ray propagation reciprocity
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MIMO static transmission channel

• MIMO channel

(NxM) RT
1 RT
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MIMO transmission channelApproximated approach

• MIMO channel matrix obtained with 1 R.T

Steering vector side a
Steering vector side b
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MIMO mutual coupling

• MIMO transmission channel with mutual coupling

As mutual coupling matrices are symmetric
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Synthesis of an antenna LOS radio link
Frequency (GHz)
Frequency (GHz)
Measured link (FT(S21))
Synthetised link from NFC measurements
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MIMO configuration
MIMO channel 2x2
fc 4 GHz B(-10dB) 2 GHz d c / fc
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MIMO channelApproaches comparison
omnidirectional antennas
directional antennas
MIMO Matrices (Exact)
MIMO Matrices (Approximated)
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AOA repartition MIMO 2x2
Omnidirectionnal antennas azimuth
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Conclusion

• Deterministic E.M simulation can be used to model
  typical UWB indoor channel situations
• We have proposed a framework which establishes a
  bridge between RT and classical channel model
  formalisms
• It take into account antenna mutual coupling and
  radiation pattern of individual elements of each
  array
• It underlines the transmission channel
  reciprocity
• This kind of simulation tool can help
• To study of the effect of antenna
• To evaluate location algorithms
• To build an heterogeneous radio environment
  simulator
• For better understanding of what amount of
  useful information the channel has to offer.

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Thank You
bernard.uguen_at_insa-rennes.fr