++si bimbo berckp tentang telco part 3

helohai... bertemu kembali kita di ruangan si bimbo nak becakap psl telco...
kali ini ai nak berkata2 mengenai radio access technology pula.

let me recap (cewah), susun galur radio technology dari zaman ke zaman:


1G -
analog phone (zaman parameswara haha telepon atur dsb)
zaman ini, we use FDMA (freq div multiple access).
maksodnye user use different frequency at the same time.

2G - 14.4kbps
GSM, GPRS (and EDGE later on)
this technology, we use TDMA (time div mul xs).
maksodnye, at the same frequency, user are using different timeslot.
1carrier ade 8 timeslot, so, at the same freq tu, user beratur utk guna 8slot tuh.
if u r now connected to GPRS (lambang bulat kalo kat iphone), kalo xde org guna voicecall, dan kalo ko dpt masuk dlm antara 8 timeslot tu, bertuah lah kau.

3G -384kbps - 14.4Mbps - 42Mbps (the latest product by the company using 2x2 MIMO)
UMTS, HSDPA, HSPA (3G lah)
at this point of tech, kite sudah guna CDMA (code div mul xs)
so, at the same time & frequency, we were differentiate by code. (eg: scrambling code dll)

4G - 173Mbps - 326Mps (theoretically)(best case scenario)
LTE
this tech is currently using OFDMA (orthogonal FDMA)
this is the time when we finally apply our 'favourite' fast fourier transform (FFT) to make sure each user are using frequencies that are orthogonal to each other. haa kau, rupa2 nye ade faedah nye fast fourier tranform yg kite belaja during maths dulu tuh.

currently listening to:ungu-demi waktu (spotify playlist)
currently feeling:kenyang nak mampossssss
i wanna be:richhhhh