Post on 14-Jan-2016
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CHANNEL SOUNDING USING USRP2 & GNU-RADIO
Channel Impulse Response And Coherence Bandwidth Estimation
By:- Rohit Sharma Jay Prakash
Under :- Prof S.N Merchant SPANN LAB,IIT Bombay
Channel Sounding UsingUSRP2 & GNU-RADIO
Increased Use of Wireless DevicesIncreased Use of Wireless Devices
Data-Intensive High Bandwidth ServicesData-Intensive High Bandwidth Services
Strain in capacity of RF SpectrumStrain in capacity of RF Spectrum
Most Communication becomes impractical above 10GHZ in Microwave Region.
Why?:- Motivation
Channel Sounding UsingUSRP2 & GNU-RADIO Multipath Effects of Channel
Multiple propagation paths:Line-of-Sight (LoS) and NLoS Invites Multipath invites:-Scattering, Reflection, Diffraction. Channel Becomes:-Frequency dependent,Time dependent and Position dependent.
Ultimately Coherence Bandwidth is adversely affected.
Channel Sounding UsingUSRP2 & GNU-RADIO
Flow Model
Channel Sounding UsingUSRP2 & GNU-RADIO
Apparatus
Channel Sounding UsingUSRP2 & GNU-RADIO
Host PC
PN code
Tx Gain
BPSK Modulation
USRP(Tx)
FPGA
DAC
RF Boar
d
RFX2400Up-
Conversion
TransmitterAntenna
Interpolation Filters , Cordic
DUC
Our Transmitter side Flow-Design
Channel Sounding UsingUSRP2 & GNU-RADIO Our Receiver side Flow-Design
USRP(Rx)
Daughter Board
ADC
FPGA
FPGA Cordic.
DDC
Data Flow
USRP(RX) Motherboard
Rx Host PC
Channel Sounding UsingUSRP2 & GNU-RADIO Host PC(Tx) Flow-chart
USRP2 Gb Ethernet Host Pc
(Transmitter)
Digital_bert_tx.py
GNU-RADIO
UHD-DRIVER
PN Sequence Vector Source
Unpack_to_pack
BPSK Differential gray coded Modulation
Uhd_Transmitter USRP2
Channel Sounding UsingUSRP2 & GNU-RADIO Host PC(Rx) Flow-chart
File Sink(.dat)
File SinkHost Pc (Receiver)
Gb Ethernet I
Q
Data Processing I
USRP2
Read Complex_to_Binary
Window/Seq
Windowing on Data-Stream Per PnSequence
Channel Sounding UsingUSRP2 & GNU-RADIO
Data Processing II
Window/Seq
Local Pn-Seq Channel Impulse
Response
Cross Correlated Data
Cross_Corr
Averaged Over Windows Average CIR
Power Delay Profile
Frequency Correlation Function
FFT
Coherence Bandwidth Estimation
Channel Sounding UsingUSRP2 & GNU-RADIO
Host PC(Rx) Flow-chart
Host Pc (Receiver)
GNU-RADIO
UHD-DRIVER
Demodulator
Stream Converter
Uhd_Receiver
Digital_bert_rx.py
Octave Based Post-Processing
File Sink(.dat)
Channel Sounding UsingUSRP2 & GNU-RADIO
Requirements:-
Our Automated-Sounder APPLICATION
Software
Gnu-Radio 3.6.0PythonOctaveUHD_Driver (Latest stable)
Hardware
USRP2(Tx,Rx)Two PCsGb Ethernet
Channel Sounding UsingUSRP2 & GNU-RADIO Our Automated-Sounder APPLICATION
Channel Sounding UsingUSRP2 & GNU-RADIO
Impulse Response of a window
Channel Sounding UsingUSRP2 & GNU-RADIO
Power Delay of the window
Channel Sounding UsingUSRP2 & GNU-RADIO
Channel Impulse Response
Channel Sounding UsingUSRP2 & GNU-RADIO
Power Delay of the window
Channel Sounding UsingUSRP2 & GNU-RADIO
Power Delay Profile
Channel Sounding UsingUSRP2 & GNU-RADIO
Frequency Correlation Function