TSM-321 Exam 5 Cellular Network Theory & Operation YOU MUST SHOW ALL WORK FOR FULL CREDIT XXXXXXXXXXName:_______________________ YOU MUST INCLUDE UNITS OF MEASURE (miles, feet, dB, etc) for full...

TSM-321 Exam 5
Cellular Network Theory & Operation
YOU MUST SHOW ALL WORK FOR FULL CREDIT Name:_______________________
YOU MUST INCLUDE UNITS OF MEASURE (miles, feet, dB, etc) for full credit.
Use the following Figure for questions 1 & 2
1
5
4
3
2
7
6
Frequency 1 = 840Mhz
Frequency 2 = 845Mhz
Frequency 3 = 850Mhz
Frequency 4 = 855Mhz
Frequency 5 – 860Mhz
Frequency 6 = 865Mhz
Frequency 7 = 870Mhz
4
3
1

1. (5 pts) What type of interference occurs between the two white cells? _______________________________
Solution: Co-channel interference (interference due to frequency reuse)
2. (5 pts) How is the interference problem identified in problem 1 usually solved? Explain how you know if the
solution is adequate to fix the problem caused by the interference.
Solution:
Unlike thermal noise which can be overcome by increasing SNR, co-channel interference cannot be combated by
simply increasing the carrier power of a transmitter. To reduce co-channel interference, co-channel cells must
be physically separated by a minimum distance to provide sufficient isolation due to propagation. When the size
of each cell is approximately the same and the BSs transmit the same power, the co-channel interference ratio is
independent of the transmitted power and becomes a function of the radius of the cell (R) and the distance
between the centers of the nearest co-channel cells (D). The parameter Q is called the co-channel reuse ratio is
related to the cluster size. For a hexagonal geometry Q=D/R= √(3N). A small value of Q provides larger capacity
since the cluster size is small whereas a large value of Q improves the transmission quality, due to smaller level
of co-channel interference .
3. (5 pts) Label the indicated architecture elements with the proper acronym.


4. (5 pts) Define the acronyms in question 3.
A. _Operation and maintenance center (OMC)____________
B. _HLR___________________________________________
C. _Base station____________________________________
D. _VLR___________________________________________
E. _ Mobile services switching center (MSC)______________
5. (5 pts) What is the primary function of the architecture element in question 4-A?
Operation and maintenance center (OMC): The OMC monitors and...