A Direct Sequence Spread Spectrum Solution to the Two-Antenna Problem

Abstract

Direct sequence spread spectrum (DSSS) techniques can be applied to solve the two-antenna problem in aeronautical telemetry. By selecting unique spreading sequences for both transmit antennas, a ground station can decode one or both signals at any given time. Spreading ensures that the two signals are sufficiently different as to not cause destructive interference at the receiver. Computer simulations demonstrate that DSSS can solve the two-antenna problem, the bit error rate performance improves as the spreading factor increases, and that a modest number of pilot bits is needed to accurately estimate the “channels” created by the two-antenna scenario.