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Final year project
This document summarizes an experiment on wideband channel sounding and measurement. It describes the objectives to characterize the power delay profile, delay spread, coherence bandwidth, and compare simulated and experimental results. The experiment involved transmitting wideband direct-sequence spread spectrum signals and measuring the reception at different indoor and outdoor locations in Singapore. The results show differences in delay spread and coherence bandwidth depending on the transmission environment and distance between transmitter and receiver. Simulated results were also compared to the experimental data. In conclusion, the channel characteristics largely depend on the location and transmission distance, and SNR plots help characterize outdoor transmission performance.
Final year project
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- 2. Overview 1. Introduction 2. Experiment 3.Results 4. Conclusion
- 3. Introduction •Collaboration between DRTech andNTU •Channel characterizations are rarely done in Singapore •Important to the military
- 4. Objectives •Power delay profile- Delay spread, coherence bandwidth (effect of multipath), Signal- Noise Ratio •Fusionopolis •Compare Stochastic (simulation) and Deterministic (experimental) results
- 5. Literature Review • Radiofrequency – 250MHz to 470MHz
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- 7. Multipath • NLOS effect •Cause a time delay or phase shifting in received power
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- 9. Wideband Channel Sounding •Channelsounding is an analysis of channel characteristics of the signal Narrowband CW Wideband •How?
- 10. Wideband Channel Sounding •Direct-SpreadSequence Spectrum –phase-modulates using PN sequence - Using chips to represent a symbol - Non return to Zero (1 1, 0-1) coding
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- 17. Delay Spread •Time differencebetween 1st sig. peak and the subsequent multipath peaks •Greater the value More chance of amplitude fading
- 18. Coherence Bandwidth •Bandwidth which2 frequencies had correlated or comparable amplitude fading •Frequency range the signal can be estimated accurately
- 19. Results – Indoorto Indoor B2 B2 L3 L3
- 20. Results – Indoorto Indoor • Indoor to indoor • Position Pic B2 L3 Trx Trx Rx Rx
- 21. Results – Outdoorto Indoor L21 L11
- 22. Results – Outdoorto Indoor • Receiver Position
- 23. Results – Outdoorto Indoor L21 320MHz 350MHz
- 24. Results – Outdoorto Indoor
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- 26. Conclusion •Largely depend onlocation (environment) and distance between rx and trx
- 27. Conclusion •SNR plot cangive a better picture of outdoor transmission •Stimulation result can be compared with experimental result
- 30. • Roll offfactor • Square root cosine filter • FYP refPrevious FYP reportChannel Characterization of Non-Line of Sight Propagation.pdf pg 30
Editor's Notes
- #6 Sweet spots based on the economic benefits that can be generated e.g. cellular applications Propagation, technical parameters, availability of equipment, antenna size are the other factors which affect the demand for certain portions
- #7 Line of Sight Non-Los: Reflection, refraction, diffraction
- #8 Line of Sight Non-Los: Reflection, refraction, diffraction
- #9 Line of Sight Non-Los: Reflection, refraction, diffraction threshold
- #10 Channel sounding analyzes transmissions to determine whether signals will travel smoothly, without distortion or interference.
- #11 BPSK modulate 1 bit/symbol http://en.wikipedia.org/wiki/Phase-shift_keying#Binary_phase-shift_keying_.28BPSK.29 Symbol rate = 25Msym/s
- #13 3min
- #17 Need to change color green to red
- #18 http://iitd.vlab.co.in/?sub=65&brch=179&sim=404&cnt=1 is a measure of the multipath richness of a communications channel it can be interpreted as the difference between the time of arrival of the earliest significant multipath component and the time of arrival of the latest multipath component. Greater the value More chance of amplitude fading
- #19 approximate maximum bandwidth or frequency interval over which two frequencies of a signal are likely to experience comparable or correlated amplitude fading Depends on different requirement and approximation Inverse relationship with delay spread 6min They can be used to estimate the maximum data rate that can be supported without the use of an equalizer
- #20 BPSK modulate 1 bit/symbol Symbol rate = 25Msym/s
- #21 Lets analyze the setting of the indoor to indoor transmission For indoor environment, the multipath is mostly affected by reflections, diffractions, refractions and path loss through the walls and floors.
- #22 Wall and roof attenuation LOS path interference includes free space, atmospheric etc. NLOS path interferences includes reflection, diffraction and scattering affected by the building height, density etc.
- #23 Let me do an analysis if the outdoor-indoor transmission.
- #24 Red area has higher SNR Blue region are further away from the receiver
- #25 When the vehicle turns, the signal suffer a large amount of loss. One of the factor can be due to the building, causing reflection or refraction.
- #26 Compare the result between the experimental PDP and stimulation PDP.
- #27 Somewhat random, so need to take more sample and attain more frames for signal averaging
- #28 13min