Adaptive locally optimum processing for moderately spread SATCOM AJ modes

Abstract

SATCOM channels with nonregenerative, saturating downlink amplifiers can be severely degraded by uplink jamming which "captures" the downlink amplifier. The use of direct sequence spread spectrum techniques to overcome the jamming leads to a large reduction in information throughput. The authors propose a moderately spread mode using AJ enhancement through use of adaptive locally optimum processing. They present simulation results for the proposed new mode. These simulations indicate that at least 6 dB additional AJ gain can be provided by the proposed processing in narrowband (less than 10% bandwidth) jamming with good downlink channel conditions (SNR greater than 17 dB).<>