| Abstract: | Pseudo-noise (PN) or direct sequence (DS) modulation, frequency hopping (FH) and their combination (i.e. the hybrid FH/PN approach) are common spread spectrum (SS) communications techniques used to achieve anti-jamming (AJ) and/or low probability of intercept (LPI). This study investigates the following FH and FH/PN related issues: (i) derive and apply M-ary phases of PN sequences to increase the AJ and transmission efficiency, (ii) use of erasure channel to reduce received errors and unreliable data, (iii) employ error correction coding and signal editing (SE) to improve communication surviv-ability, and (iv) adopt surface acoustic wave (SAW) devices to simplify the synchronization procedure in PN correlation. A special example is also given to illustrate the potential AJ improvement when an SS communications system employs both concatenated coding and concatenated SE techniques. |
