$4.$ You are designing a GSM system and need to know how much RF spectrum to acquire. The following specifi$-$

cations describe the system and the expected behavior of its subscribers:

$$ Cluster size: N $=7$ cells$/$cluster

$$ Cell radius: R $=1$ km

$$ Subscriber density: $77$ customers per km$2$

$$ Per$-$user call request rate: $5$ calls$/$hour

$$ Average call duration $($holding time$)$: $55$ seconds

$$ Maximum acceptable probability of blocking: $0\mathrm{.}01$

$$ Bandwidth of one RF channel: $200$ kHz

$$ Number of voice channels per RF channel: $8($due to using TDMA technology$)$

Assume hexagonal shaped cells $($for the purpose of computing cell area$).$ Determine the minimum amount of

bandwidth $($in MHz$)$ required for the system to meet the above specifications. To do this, you should first

compute the number of voice channels required per cell, then determine the number of RF channels per cell.

Finally, you can determine the number of RF channels for the entire cluster. Hint: The area of a hexagon with

radius R is $3$

$$

$3$

$2$ R$2$

$.$