INSTITUT D’ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES 1 UMR 6164 A reciprocal MIMO-UWB...

INSTITUT D’ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES

1UMR6164

A reciprocal MIMO-UWB Radio Channel Deterministic Modeling Framework

CROWNCOM - 2006Mykonos June 10

B. Uguen,L.-M. Aubert, F. Tchoffo Talom, [email protected]

CROWNCOM 2006 June 10 2006

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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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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

Interest of site-specific channel simulation

Site-specific channel simulation can be advantageously used to


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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: Txb: Rxk: rayl: 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 fieldAntenna 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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UWB antennas used for channel sounding

Conical Monocone AntennaCMA-118/A1.0-18 GHzA.R.A

Fréquence (GHz) Fréquence (GHz)

S11

(dB

)

S11

(dB

)

Cornets large bande1.0-12 GHz

Tx Rx


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Synthesis of an antenna LOS radio link

Frequency (GHz) Frequency (GHz)

Synthetised link from NFC measurements Measured link (FT(S21))


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Tx & Rx antennas : CMA-118

The antenna is


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... strongly modifying the transmission

channel

Tx et Rx antenna : Wideband horn antennas


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MIMO configuration

MIMO channel 2x2 fc = 4 GHzB(-10dB) = 2 GHzd = c / fc


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MIMO channelApproaches comparison

omnidirectional antennas

MIMO Matrices (Exact) MIMO Matrices (Approximated)

directional antennas


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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

[email protected]

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INSTITUT D’ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES 1 UMR 6164 A reciprocal MIMO-UWB...

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