alshehri
Newbie level 2
Simulate Rayleigh Flat Fading Channel
A broadband radio channel needs to be specified in two aspects. The power-delay
profile describes a statistical power distribution of the channel over time for a signal
transmitted for only an instant. On the other hand, the Doppler power spectrum offers
a statistical power distribution of the channel versus frequency for a signal transmitted
at one exact frequency.
For a flat fading channel, there is a constant gain and linear phase response over a
bandwidth which is greater than the bandwidth of the transmitted signal. However,
the strength of the received signal changes with time, due to fluctuations in the gain
of the channel caused by multipath. For a Rayleigh flat fading channel, the envelope
amplitude of the received signal at one time instant follows a Rayleigh distribution.
On the other hand, regarding the time correlation of the channel, it depends on the
surrounding environment and movement of the mobile. Consider a uniform scattering
environment introduced by R. H. Clarke and later developed by W. C. Jakes. In the
model, it is assumed that a waveform arrives at a receiver after being scattered on a
very large number of scatterers. These scatterers are assumed to be randomly located
on a circle centered on the receiver. In the environment it is assumed that there is no
line-of-sight (LOS) signal with a power notably larger than the rest. Consequently, the
received waveform is made of the superposition of many waveforms arriving from the
scatterers at an angle that is uniformly distributed between 0 and 2π. Under such a
uniform scattering environment,
where Pr is the average received power owing to shadowing and pathloss and fD
Doppler frequency spread.
? ? How to write a computer program to generate a Rayleigh fading signal envelope with a desired
Doppler spread fD . Based on the program, draw two sample instances given that a
carrier frequency fc = 1850 MHz and the mobile’s moving velocity is 60 mph, and
80 mph, respectively.
A broadband radio channel needs to be specified in two aspects. The power-delay
profile describes a statistical power distribution of the channel over time for a signal
transmitted for only an instant. On the other hand, the Doppler power spectrum offers
a statistical power distribution of the channel versus frequency for a signal transmitted
at one exact frequency.
For a flat fading channel, there is a constant gain and linear phase response over a
bandwidth which is greater than the bandwidth of the transmitted signal. However,
the strength of the received signal changes with time, due to fluctuations in the gain
of the channel caused by multipath. For a Rayleigh flat fading channel, the envelope
amplitude of the received signal at one time instant follows a Rayleigh distribution.
On the other hand, regarding the time correlation of the channel, it depends on the
surrounding environment and movement of the mobile. Consider a uniform scattering
environment introduced by R. H. Clarke and later developed by W. C. Jakes. In the
model, it is assumed that a waveform arrives at a receiver after being scattered on a
very large number of scatterers. These scatterers are assumed to be randomly located
on a circle centered on the receiver. In the environment it is assumed that there is no
line-of-sight (LOS) signal with a power notably larger than the rest. Consequently, the
received waveform is made of the superposition of many waveforms arriving from the
scatterers at an angle that is uniformly distributed between 0 and 2π. Under such a
uniform scattering environment,
where Pr is the average received power owing to shadowing and pathloss and fD
Doppler frequency spread.
? ? How to write a computer program to generate a Rayleigh fading signal envelope with a desired
Doppler spread fD . Based on the program, draw two sample instances given that a
carrier frequency fc = 1850 MHz and the mobile’s moving velocity is 60 mph, and
80 mph, respectively.
