Chapter 5 Mobile Radio Propagation SmallScale Fading and
Chapter 5: Mobile Radio Propagation: Small-Scale Fading and Multipath as it applies to Modulation Techniques © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Principles and Practice 2 nd Edition T. S. Rappaport rohibited. Wireless Communications
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Doppler Shift Geomerty
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Channel issues
© 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Consider a transmitter which radiates a sinusoidal carrier frequency of 1850 MHz. For a vehicle moving 60 mph, compute the received carrier frequency if the mobile is moving a) directly towards the transmitter b) directly away from the transmitter c) in a direction which is perpendicular to the direction of arrival of the transmitted signal. rohibited. Example 5. 1
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 1
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 1
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Complex Baseband model for RF systems
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Time-varying impulse response
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Measured impulse responses
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Channel Sounder: Pulse type
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Channel Sounder: PN Type
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Channel Sounder: Swept Freq. type
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Measured power delay profiles
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Indoor Power Delay Profile
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Typical RMS delay spreads
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Time Dispersion Parameters •
Time Dispersion Parameters The mean excess delay is the first moment of the power delay profile and is defined to be The rms delay spread is the square root of the second central moment of the power delay profile and is defined to be (5. 36) (5. 37) © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p rohibited. (5. 35)
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Time Dispersion Parameters •
Example 5. 2 a) , and © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p If the number of multipath bins is fixed at 64, find rohibited. Assume a discrete channel impulse response is used to model urban radio channels with excess delays as large as 100 s and microcellular channels with excess delays no larger than 4 s. b) the maximum bandwidth which the two models can accurately represent. Repeat the exercise for an indoor channel model with excess delays as large as 500 ns. As described in section 4. 7. 6, SIRCIM and SMRCIM are statistical channel models based on equation (5. 12) that use parameters in this example.
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 2 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Example 5. 3 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 3
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 3
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 3
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 3
Estimate the 50% coherence bandwidth of the channel. Would this channel be suitable for AMPS or GSM service without the use of an equalizer? © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Calculate the mean excess delay, rms delay spread, and the maximum excess delay (10 d. B) for the multipath profile given in the figure below. rohibited. Example 5. 4
Solution 5. 4 The rms delay spread for the given multipath profile can be obtained using equations (5. 35)-(5. 37). The second moment for the given power delay profile can be calculated as © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p The mean excess delay for the given profile rohibited. The delays of each profile are measured relative to the first detectable signal.
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 4 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Example 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 5 •
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Two independent fading issues
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Flat-fading (non-freq. Selective)
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Frequency selective fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Two independent fading issues
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Rayleigh fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Small-scale envelope distributions
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Ricean and Rayleigh fading distributions
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Small-scale fading mechanism
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Doppler Effect and Frequency Variations Doppler spectrum
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Spectrum of Envelope of doppler faded signal
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Simulating Doppler/Small-scale fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Simulating Doppler fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Simulating Doppler fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Simulating multipath with Doppler-induced Rayleigh fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Simulating 2 -ray multipath
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p SIRCIM Simulation of all indoor propagation Characteristics
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p SMRCIM Simulation of all outdoor propagation Characteristics
© 2002 Pearson Education, Inc. Commercial use, distribution, or sale p • Available from Wireless Valley Communications, Inc. • Source code in C is available • www. Wirelessvalley. com rohibited. SIRCIM and SMRCIM
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Angular Spread model
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Spatial distribution of Multipath
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Angular Spread key to fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Spatial orientation of multipath impacts the depths of fading
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Angular Distribution of power
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Angular Spread predicts correlation distances
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Angular Spread predicts correlation distances
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Example 5. 6
rohibited. © 2002 Pearson Education, Inc. Commercial use, distribution, or sale p Solution 5. 6
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