ABSTRACT
Communication involves the transfer of information between a source and a user. Many sources may attempt to transfer information through one satellite transponder with the result that the available communication capacity of the transponder is shared between several earth terminals. This sharing technique is called multiple access (MA). The term access, in satellite transmission systems, usually refers to multiple access. Sharing can be in many formats, such as sharing the transponder bandwidth in separate frequency slots (frequency division multiple access [FDMA]), sharing the transponder availability in time slots (time division multiple access [TDMA]), or allowing coded signals to overlap in time and frequency (code division multiple access [CDMA]). D in the acronyms stands for “division.” Division implies switching. The various transmission switching techniques are discussed in much detail in this chapter.
