Report

Estimation and analysis of propagation channels based on stochastic methods Binh Tran – Manoj Adhidari ECEn 670 - Project Brigham Young University 1 Binh Tran • Satellite communication • Applications • Multi paths environment • Rayleigh channel model • pdf/ CDF of E field • pdf/CDF of SNR • Single Tx, single Rx • Single Tx, multiple Rx • Selection Diversity • Future Work 2 Binh - Manoj • Satellite communication: Wireless form of communication between two satellites satellite and multiple antennas • Applications: Wide area network communications, weather forecasting, radio communication, internet access, global position system • This project: Satellite is the fixed transmitter Dish antenna as a moving receiver Array antenna at receiver Scatters randomly located between Tx/Rx Signal uncorrelated 3 Binh - Manoj • Multipath Effects: Reflection from earth Blockage or shadowing Diffraction Interference due to multipath • Propagation Chanel: Characterize multipath effects Long term averaged signal reduction Distance between the Tx and Rx Locations of Rx/Tx and Scatters 40 Y-axis • Rayleigh Channel Model: No strong line of sight between Tx and Rx Uncorrelated signals The reflections add coherently at the receiver Fading phase differences between propagation paths Pdf of 4 E is Rayleigh distribution Binh - Manoj 30 20 10 0 -10 -20 -30 -40 0 20 40 60 X-axis 80 100 • Rayleigh Model : pdf of electric field • SNR: Mean SNR CDF of electric field Pdf of SNR Nscat = 10 R = 100 m Var = 10*R CDF of SNR Electric field model More scatters, more loss More dense (small variance), more loss 5 Binh - Manoj One branch the probability of the received SNR Probability that all M branches will have SNR less than threshold Nscat = 50 R = 100 m Var = 10*R Average SNR Higher the number of element, antenna steeper the slope of the CDF Higher number of antenna, the probability of getting SNR is better 6 Binh - Manoj SNR at receiver in term of number of Antenna (Simulation vs Theory) SNR at receiver in term of number of Antenna (Simulation vs Theory) -43.5 -41 -44 -42 -45 Simulation Theory -43 Simulation Theory SNR (dB) SNR (dB) -44.5 -45.5 -44 -45 -46 -46 -46.5 -47 0 0.5 1 1.5 2 2.5 Number of antennas at receiver 3 3.5 4 -47 0 1 2 3 8 7 6 5 4 Number of antennas at receiver 9 More antenna at receiver, better SNR Improvement is not linear with increasing number of receiver antennas 7 Binh - Manoj 10 11 Raleigh Fading occurs in a no line of sight propagation environment Various probability distributions were plotted which characterized the SNR SNR for multiple receiver system was also obtained and discussed The results obtained from simulation matched well with the theoretical results Depending on different applications, assumptions and models were used This model helps us analyze and predict the performance of the system The future work will focus on applying different algorithms to estimate the propagation channels and steering beam pattern for maximum SNR 8 Binh - Manoj • Acknowledgements: Dr. Mazzeo for his help and guidance Classmates for their opinions, suggestions and discussions 9 Binh - Manoj