ABSTRACT
This chapter reviews spread spectrum techniques: starting from the more intuitive frequency and time hopping approaches to the more recent and promising Direct Sequence-Code Division Multiple Access (DS-CDMA). In the frequency space the spread spectrum communication is called Frequency Hopping. An intentional jamming signal that does not known the Hopping Sequences is unable to systematically disturb the useful signal and the jamming effects decrease as the bandwidth increases. In the time space the spread spectrum communication is called Time Hopping. In the code space the spread spectrum communication is called Direct Sequence. Serial joint-detection systems or serial cancellers attempt to first decode the more reliable users, that is the users with higher received power. It then uses this decoded bits to cancel the contribution of these users from the global signal. The parallel joint detection mechanism or parallel canceller proceeds with a multistage approach.
