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Radio Resource ManagementAdaptive Modulation/Integrated RRM
Radio Modem Research at WINLAB (pre July 2001)
PHYInterference Cancellation, Channel
Estimation, Channel Coding
RF Devices/Circuits ?Radio waves anybody ?
Soft
ware
Rad
io
Test
bed
SSF
Sim
ulat
ion
Test
bed
Radio Resource ManagementAdaptive Modulation/Integrated RRM
Radio Modem Research at WINLAB (post July 2001)
PHYInterference Cancellation, Channel
Estimation, Channel Coding
RF Devices/CircuitsWINLAB is on to Radio Waves!
Syst
em O
n Ch
ip
Soft
ware
Radi
o &
SSF
Sim
ulat
ion
Test
beds
Radio Modem Research (Pre 1999)
1kh BS k
2kh 3kh
14h BS 1
15h 16h
4kh
5kh
For anytime anywhere cellular serviceMultiuser Interference Cancellation at BSSimulation Studies on WiPPET SSF simulatorImplementation Studies on Software Radio Testbed
MS 1
MS 2
MS N
BS j
BS 1
BS 12
MS x
RAYLEIGH (short time-scale losses)
MOBILITY/GEO (long time-scale losses)
SWITCH
FwdRCH
RevRCH
WiPPET
Multicell
Mobility
Radio Resource Mgmt
Signal Processing
Propagation
Scalable Simulation Framework
SDR Testbed based on FPGAs and DSPs
SDR Architecture for Interference Cancellation
Channelizer
ReconfigurableMatched Filter
Info. Bit-streamProcessing
On-lineEstimation
Control andOff-line Estimation
DSP
FPGA
Wideband A/D
Channelizer
Bit. Proc.User 1
Control andOff-line Estimation DSP
FPGA
Wideband A/D
On-lineEstimation
SIC FILTERUser 1
SIC FILTERUser N
SIC FILTERUser 2
…
Bit. Proc.User 2
Bit. Proc.User N
Linear MUD Nonlinear SIC
Radio Modem Research (post 1999)
High rate data servicesInterference Cancellation for the DownlinkDetection & Characterization of Impulsive interferenceSpace/Time Processing & CodingMulticarrier/OFDM, Ultra Wideband (UWB)Characterization of High Speed Short Range Channels
1kh BS k
2kh 3kh
1kh BS 1
2kh 3kh
Small, separated “cells”Low power (~100 mw)Brief connections (~1 sec)Very high bit rate (~1 G bps)Simple infrastructure (LAN on a pole, IP access)Unlicensed bands ?
Maps and images
Internetaccess
Music,voicemail,
news
InfostationsA system of sweet spots for “free” bits
About 15 student projects in the RF/MODEM area
InvestigatorsEvansGreensteinLinLuMandayamSeskarSpasojevicYates
JGE 10/01
WiPPETSSFSIMULN.
INTERFERENCECANCELLATION
SOFTWARERADIOTESTBED
CODING
OFDM UWB
SYSTEM ON
CHIP
CHANNELMEAS.
SENSORS
RF
DEVICES
Range of Systems
3G Cellular
Wireless LANs
Infostations
Ad hoc Data
Common ThemeEfficient High Data Rate Transmission
• Propagation/Channel Modeling– Infostation & UWB channel models
• Outdoor & indoor channel measurements for typical scenarios – Greenstein, Mandayam, Seskar
• Interference Cancellation– “Blind” receiver techniques for the handset
• Exploit 2nd order statistics for mitigating unknown interferers– Mandayam, Seskar
– Wippet multicell downlink simulations • Characterization of power profiles and performance evaluation
– Spasojevic, Yates– Impulsive/Wideband interference cancellation
• Robust detection under alpha-stable models for interferers – Spasojevic
Common ThemeEfficient High Rate Data Transmission
• OFDM– Peak power reduction
• Heuristic iterative clipping algorithms– Evans
– Synchronization for Infostation channels• Algorithms & implementation on Testbed
– Mandayam, Seskar, Spasojevic• Space/Time Turbo Coding
– Performance on correlated fading channels• Impact of spatial & temporal correlations
– Mandayam• UWB
– Analysis, cancellation, synchronization• Several new projects being initiated
– Evans, Mandayam, Seskar, Spasojevic