FDMA Frequency Division Multiple Access, here entire band of frequencies is divided into multiple RF channels/carriers. Each carrier is allocated to different users. For example in GSM entire frequency band of 25 MHz is divided into 124 RF carriers of bandwidth 200 KHz each. In Satellite applications entire transponder band of 500 MHz is divided into 24 channels each of bandwidth 40MHz (36 MHz useful and 4MHz guard band).
TDMA -Time Division Multiple Access, here entire bandwidth is shared among different subscribers at fixed predetermined or dynamically assigned time intervals/slots. For example in GSM each RF carrier is used/shared by 8 users at different time instants.
CDMA-Code Division Multiple Access, here entire bandwidth is shared among different users by assigning unique codes. For example in CDMA IS-95 standard entire bandwidth of 1.225 MHz is shared by various channels/users using unique 64 Walsh Codes.
For More information about FDMA, CDMA and TDMA Plz refer link: http://learnabouttelecom.blogspot.in/2012/06/difference-between-fdma-cdma-and-tdma.html
