Smart Antenna Research Underthe GloMo Program

Smart Antenna Research Underthe GloMo Program

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The ProblemThe Problem

BaseStation

Uplink

Multipath

Uplink

Mobile

Downlink Multipath

IntercellInterference

Signal Fading

Limitations on Capacity•Co-channel interference•Multiple access interference•Adjacent channel interference•Multipath, fading, and noise

Apparent SolutionDSP Interference Rejection Techniques

Reality of the Solution•High power consumption•Excessive computing needed

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Research AreasResearch Areas

l Adaptive Antenna and DirectionFinding Algorithms and Hardware

l Hand-Held Smart Antennasl Vector Channel Modeling

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Adaptive Antenna andDirection Finding

Algorithms and Hardware

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Code Timing

Spatial Filters

DespreadersDemodulator

andBeamforming

Algorithm

Front End for Antenna 1ADC / DDC

(SigTek ST-114)BPFIF

AMP

Local Oscillator

X IF LPF

~f=1982 MHZ

f=2050 MHZ

Front End for Antenna 8ADC / DDC

(SigTek ST-114)BPFIF

AMP

Local Oscillator

X IF LPF

~f=1982 MHZ

f=2050 MHZ

ApplicationsDemonstrateinterference

rejection throughspatial filtering

Study algorithmperformance

Perform AoA estimation forposition location applications

Developing spatialchannel models

Third Generation Array

DSPTI C549/C541

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Multi-Target CMAMulti-Target CMA

CMA

+

CMA

+RF Front End

&Baseband conversion

RF Front End&

Baseband conversion

RF Front End&

Baseband conversion

Gram-SchmidtOrthogonalizer

User 1 output

User M output

1

2

M

Port # 1

Port # M

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Accomplishmentsl Smart Antennas at the HandsetÕ Created and built 2 measurement systems to measure

propagation characteristics as seen by the handsetÕ Initial data collection shows an improvement of up to

17 dB in the link budget with adaptive combining and7dB with diversity combining

Antenna Unit

VectorChannelMeasurementSystem

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MPRG Vector Measurement SystemMPRG Vector Measurement Systeml Fully functional 8 elements,1.25 MHz Bandwidth, 2.050GHz center frequency

l Flexible for adapting variousantenna/polarization inputs,carrier frequencies,bandwidths, real-timealgorithms, or data collectionscenarios

l Eight Harris 40214Programmable Direct DigitalDownconverters, eight C54xDSPs, one Analog Devices21010

l New features being addedÕ CDMA capabilityÕ Improved systemexecutive processing

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Research IssuesResearch Issues

l Adaptive array algorithm performancein real situations

l Vector channel measurementsl Practical AOA algorithm and

hardware developmentl Adaptive array algorithm convergence

issues

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Future Work - Summer 98 ResearchFuture Work - Summer 98 Research

MPRG's vectormeasurement system willbe located at a point alongthe Smart Road and willestimate the angle at whichthe signal arrives at thearray. This angle definesthe line of bearing.Channel measurements willalso be made to quantifythe impact of the channelon measurement accuracy.