Page 403 - Integrated Wireless Propagation Models

T h e l e e C o m p r e h e n s i v e M o d e l - I n t e g r a t i o n o f t h e T h r e e l e e M o d e l s 381

M
Since Eqs. (6.5.5.2.1) and (6.5.5.2.2) are equal, we can solve a s
G,G"'
1
Pr
M - A dY · N · L ( E ) (6.5.5.2.3)
x
-
b
_
o
o
N 0 · R b
req
We denote
ERP = P ,G,
D = A dY
M
Then expressing the link margin i n dB is
M (in dB) = ERP + G"' - D -(:t ) - R b -No - Lo (in dB) ( 6.5.5.2.4)
0 req
From Eq. (6.5.5.2.4), all the parameters are known, and we can obtain a derived
value of M by adjusting ERP, that is, either the transmitting power or the transmitting
antenna gain.

a
6.6 How to Pl n and Design a Good Wireless System
Designing a good wireless system is just like playing a game. There are many challenging
factors. Two important factors are the two Cs: coverage and capacity. These are related. You
may sacrifice capacity for coverage or vice versa. They all involve cost. Therefore, in design­
ing a macrocell system, coverage is more important than capacity. Then in terms of both
coverage and capacity, the microcell system should be deployed. In the microcell system,
reducing interference is a key task. The in-building (picocell) system will be used for the
2
need of system capacity only. These are the general concepts of designing a system. 9
6.6.1 Understanding the System Requirement
The system requirement would include the budget, the size of deployed area, the qual­
ity of the system needed, the number of carrier channels, the frequency reuse plan,
foreseen system growth, the competition factor, the characteristic of the equipment, the
capability of the designing engineers, and the zoning issues from the local government.

6.6.2 Choosing the Right Prediction Model
For exploring a general system deployed area without going into detail, an area-to-area
model is suitable. The area-to-area prediction model is used when both locations of
base station and mobile are not specified. The other two kinds of prediction models are
point-to-area and point-to-point. The point-to-area prediction model is that the location
of base station is specified but not the mobile. The point-to-area model is not very
practical to be used and seldom developed. The third one is the point-to-point prediction
model. Both locations of the base station and the mobile are specified. The point-to­
point prediction model is very useful in choosing the right locations for the base stations
when a system is deployed.
6.6.2. 1 For Macrocell Systems
The simple but fairly accurate prediction models would be chosen for the macrocell
system. The prediction model has to have a system design capability. Check for the