level model is called the microscopic fading model which focuses on the study of the
short-term received signal strength (over a few A) due to constructive and destructive
interference of the multipath. Figure 1.2 illustrates the three level models of wireless
channels.
The path loss model is usually used for system planning, coverage analysis and
link budget [271]. On the other hand, the shadowing model is usually used for power
control analysis, second order interference analysis as well as more detailed coverage
and link budget analysis [ 1.521. Finally, the microscopic fading model is usually used
for the detail design of the physical layer transmitter and receiver such as coding,
modulation, interleaving, etc. [320]. In this chapter, we elaborate the three level
models using a qualitative approach in the following sections.
1.2 LARGE SCALE PATH-LOSS
Path loss model focuses on the study of the large scale variation on the average
received signal strength due to variation in distance between the transmitter and the
receiver [203]. The simplest path loss model is thefree space path loss model where
the averaged received signal strength is inversely proportional to the square of the
distance between the transmitter and the receiver. For instance, the received signal
power P, is given by:
Pt Gt Grc2
P, = 167r2d2 f
where c is the speed of light, Pt is the transmitted power, Gt and G, are the transmit
and receive antenna gains, d is the distance separation between the transmitter and
the receiver and f is the carrier frequency of the transmitted signal. In dB form, the
received signal power is given by:
Pr(dB)=Pt(dB) + K – 20 log10 d- 20log10f
Figur 1.2 Three level channel models for wireless systems
Define the path loss as:
PL(dB) = Pt(dB) - P,(dB).
Hence, the free space path loss equation[23] is given by:
PL(dB) = -K + 20 log10 d + 20 loglo f
d
= PL(d0) + 2010g,o -
do
(1.1)
for some reference distance do. The path loss equation indicates how fast the received
signal strength drops with respect to the change in distance. For example, the received
signal strength is reduced by 4 times if we double the distance between transmitter
and the receiver or double the carrier frequency. The inverse square law is a direct
result of the Maxwell wave equation [23] in free space and can be used to model the
signal loss due to line-ofsight (LOS) propagation mode where the transmitter and
receiver can see each other.
short-term received signal strength (over a few A) due to constructive and destructive
interference of the multipath. Figure 1.2 illustrates the three level models of wireless
channels.
The path loss model is usually used for system planning, coverage analysis and
link budget [271]. On the other hand, the shadowing model is usually used for power
control analysis, second order interference analysis as well as more detailed coverage
and link budget analysis [ 1.521. Finally, the microscopic fading model is usually used
for the detail design of the physical layer transmitter and receiver such as coding,
modulation, interleaving, etc. [320]. In this chapter, we elaborate the three level
models using a qualitative approach in the following sections.
1.2 LARGE SCALE PATH-LOSS
Path loss model focuses on the study of the large scale variation on the average
received signal strength due to variation in distance between the transmitter and the
receiver [203]. The simplest path loss model is thefree space path loss model where
the averaged received signal strength is inversely proportional to the square of the
distance between the transmitter and the receiver. For instance, the received signal
power P, is given by:
Pt Gt Grc2
P, = 167r2d2 f
where c is the speed of light, Pt is the transmitted power, Gt and G, are the transmit
and receive antenna gains, d is the distance separation between the transmitter and
the receiver and f is the carrier frequency of the transmitted signal. In dB form, the
received signal power is given by:
Pr(dB)=Pt(dB) + K – 20 log10 d- 20log10f
Figur 1.2 Three level channel models for wireless systems
Define the path loss as:
PL(dB) = Pt(dB) - P,(dB).
Hence, the free space path loss equation[23] is given by:
PL(dB) = -K + 20 log10 d + 20 loglo f
d
= PL(d0) + 2010g,o -
do
(1.1)
for some reference distance do. The path loss equation indicates how fast the received
signal strength drops with respect to the change in distance. For example, the received
signal strength is reduced by 4 times if we double the distance between transmitter
and the receiver or double the carrier frequency. The inverse square law is a direct
result of the Maxwell wave equation [23] in free space and can be used to model the
signal loss due to line-ofsight (LOS) propagation mode where the transmitter and
receiver can see each other.
to be continue.............