Difference between OFDM, OFDMA, SS-OFDM, MC-CDMA, GMC-CDMA

[saeddawoud]

Hello

Can anybody tell me briefly the difference between the followings:

1- OFDM
2- OFDMA
3- SS-OFDM
4- MC-CDMA
5- GMC-CDMA

Thank in advance

 

[abaidullah]

Re: I need answers

1- OFDM : orthogonal frequency division multiplexing... the data is transmitted using a set of frequencies which are orthogonal

2- OFDMA... MA is multiple access technique for orthognal frequency division
3- SS-OFDM: is a hybrid technique using spread spectrum and OFDM
4- MC-CDMA : MCcdma is multi- carrier code division multiple access ... multiple carriers are transmitted from the same tx which are cdma-ed

 

[saeddawoud]

Re: I need answers

Ok, thanks
but can you expalin with little more detail about how using the subcarriers, i.e.: number of subcarriers/user, symbol? for example: in conventional OFDM we use N subcarriers to transmit N symbols for the same user. what about the others?
Thanks in advance