$($c$)($i$)$ State three types of $3$G network technologies.

$(3$ marks$)$

$($ii$)$ A GSM $900MHz$ digital cellular network has the following characteristics:

Up$-$link and down$-$link of $925-945MHz$ and $965-985MHz$ respectively.

$RF$ channel spacing $=400kHz$

Number of users per RF channel $=16.$

Determine the:

I. channel bandwidth;

II$.$ up$-$link RF channels;

III. total number of up$-$link TDM channels.

$(7$ marks$)$