Question

If a total of 33 MHz of bandwidth is allocated to a particular FDD cellular telephone system which uses two 25 kHz simplex channels to provide full duplex voice and control channels, compute the number of channels available per cell if a system uses 4-cell reuse
1. 55
2. 660
3. 95
4. 165

Answer 1

Correct Answer - Option 4 : 165

Concept:

Frequency reuse

1) It is the design process of selecting and allocating channel groups for all of the cellular base stations within the system.

2) Consider a cellular system that has a total of S duplex channel

3) If each channel allocated a group of k channels (k < S) and

4) If S channels are divided among N cells into the unique and disjoint group.

5) Then, the total number of radio channel available can be expressed as S = kN

Calculation: 

Given,

Cluster size (N) = 4

Total bandwidth = 33 MHz

Channel bandwidth = 25 kHz × 2 simplex channel 

Channel bandwidth = 50 kHz/duplex channel

Total available channels = (33,000 × 10³)/(50 × 10³)

Total available channels = 660 channels

Total number of available channel per cell = (Total available channels)/N

Total number of available channel per cell = 660/4

Total number of available channel per cell = 165

Hence, option (4) is correct