Linear vs. bilinear time-frequency methods for interference mitigation in direct sequence spread spectrum communication systems

Abstract

Recently, time frequency signal representations have been examined for interference mitigation in spread spectrum (SS) communication systems. In this paper, we implement a direct sequence spread spectrum @S-SS) system with additive jamming and utilize two distinct time-Pequency (t-j.l methals to mitigate the interference, namely the shp-covariant class of time fiequency distributions (TFD) and the Gabor transform. The TPD is a bilinear transfmm and is shown to improve the receiver characteristics in a highly nonstationary jamming environment. The Gabor transform is a linear method that has real-time computational advantages yet has a limited class ofjammers against which it performs well. A common feature in these two excision methods is that the t-f points are analped with the same time res olutions and fiequency resolutions. Perfomzance of both methals under several jamming scenarios is dhcussed and computational considerations w e addressed.

Real Time System Applications in Spread Spectrum Communication: A Literature Review

“…DSSS uses short as well as long sequence as the spreading sequences approved by IEEE 802.11 standards. Spread spectrum techniques are used because of several advantages including 1) inherent security of the information signal, 2) low probability of interference and detection i.e., LPI & LDI, 3) highly resistive to noise 4) anti-jamming 5) multiple use of single frequency band [1,2] and much more.…”