Not all companies rolled out 4G in Pakistan in 2014. And spectrum changes happened when users increases. Zong launched 4G with 10 MHz and Now their 4G total spectrum is 30 MHz and in future they will need more.
Similarly Jazz has largest 4G customer base in Pak. They are providing 2 way CA in 1800 and 900 MHz all over Pakistan. Since their 1800 and 900 MHz spectrum is contiguous they are experimenting with 3 way CA. Since 3G users are decreasing day by day, they think that 5 MHz of 2100 MHz is enough for 3G. So they are refarming 5 MHz out of 10 MHz for 4G. Parallely they have 14.4 MHz of 900 MHz. So they are considering to use 5 or 10 MHz out of it based of locations. So their 3 Way CA will in future be based on 20 MHz of 1800 MHz + 5 MHz of 2100 MHz + 5 or 10 MHz of 900 MHz. So once experiments successfully made we can see 30 or 35 MHz Jazz 4G depending on locations.
Zong has 25Mhz spectrum in the twin cities. They use 10Mhz for 2100Mhz (not sure where they're stealing the extra 5Mhz from) and 15Mhz for 1800Mhz.
Jazz has 25Mhz spectrum in a few remote places (even in the twin cities). Not all areas have CA so you'll see 20Mhz almost everywhere.
Regardless, in most places where signal strength is crap, Jazz still delivers better speeds (assuming backhaul is sufficient... And Jazz has begun to get choked on that now too; Zong's backhaul is iffy iffy and their data speeds/signals are also iffy iffy vs Jazz).
The spectrum for all operators is now contiguous (PTA did some reshuffling some time back). 3CA can only happen when there's non-contiguous spectrum.
XPremiuM:
