Wireless Channel Estimation
Faisal Darbari
University of Strathclyde
faisal@eee.strath.ac.uk
Introduction
• To determine the relationship between the
Received and the Transmitted signal.
• Determination of Channel Parameters
– Fading Characteristic
– Higher Order Channel Statistics
– Data Rate and the required Bandwidth
– Power Issues, BER and Equalization
– Noise and Interference
Speckled Computing Wireless Channel Estimation Faisal
Sequence Of Presentation
• Channel Measurement and Simulation
• Channel Model
– Large Scale Fading Effect
– Small Scale Fading Effect
• Future Work
• Question and Answer Session
Speckled Computing Wireless Channel Estimation Faisal
Channel Measurement and Simulation
• Experimental and Simulation Techniques
• The proposed design is a combination of two
• Calibration
Time Domain Measurement
• Pulse Generation
Technique
• Resolution
• Transmission
• Antenna
Gaussian Pulse
Generator
Digital-Scope • Multi-Path
• Detection
• Fading Statistics
Speckled Computing Wireless Channel Estimation Faisal
Channel Measurement and Simulation
Vivaldi Antenna
CPW Monopole
Bow Tie
Patch Antenna
Speckled Computing Wireless Channel Estimation Faisal
Large Scale Fading
Distance from Received
Average Path loss as a function Transmitter the Transmitter Power
and Receiver separation [cm] [dBm]
5 -7.5
10 -12.2
5 10 15 20
15 -14.5
20 -16.5
MMSE Technique is used to compute the
average path loss.
Sample Variance is calculated and can be
added in the received power.
Speckled Computing Wireless Channel Estimation Faisal
Large Scale Fading
Speckled Computing Wireless Channel Estimation Faisal
Channel Characteristic
Speckled Computing Wireless Channel Estimation Faisal
Channel Characteristic
50Psec
500 Psec
Speckled Computing Wireless Channel Estimation Faisal
Small Scale Fading
• Multipath in the radio channel creates small
scale fading.
• The Channel Delay Spread is measured to
obtain the fading x-ties.
• Second Order Statistic can be obtained:
– Bandwidth
– Data Rate
– BER
– Level Crossing and Fading Rate
– Coherence Bandwidth..
Speckled Computing Wireless Channel Estimation Faisal
Small Scale Fading
Speckled Computing Wireless Channel Estimation Faisal
Frequency Spectrum (Vivaldi Antenna)
Speckled Computing Wireless Channel Estimation Faisal
Secondary Statistic
Speckled Computing Wireless Channel Estimation Faisal
Small Scale Fading
Speckled Computing Wireless Channel Estimation Faisal
Future Work and Relevance to Specknet
• Channel Sounding with appropriate sized
antenna with..
– Different Scenarios (LOS, NLOS).
– Estimation of Noise Floor.
– Different Operating Environments with due
consideration of material losses.
– With Higher data rates the channel become
frequency selective.
– SNR and BER relation ship
Speckled Computing Wireless Channel Estimation Faisal
Acknowledgment
• Mr Ian McGregor
• Mr Griogair Whyte
Speckled Computing Wireless Channel Estimation Faisal