This is regarding the terms from Computer Networks TDMA and FDMA. These two pre-3G technologies that have been utilized to improve the performance of the 2G network.
FDMA (Frequency Division Multiplexing Access):
FDMA is a method of dividing a single band into 30 discrete channels. Each channel would then be capable of handling separate traffic, whether it’s a call or a data transfer. This is a higher level of multiplexing and should not be confused with FDM (Frequency Division Multiplexing) which is a low level multiplexing process and occurs on the physical layer. FDMA hardware includes high performance filters that also help it in avoiding near-far problems which can deteriorate the call quality.