COMMON DETECTORS FOR TIER 1 MODULATIONS

Abstract

The ARTM Tier 1 waveforms include two versions of Feher patented QPSK (FQPSK-B and FQPSK-JR) and a version of shaped offset QPSK (SOQPSK-TG). In this paper we examine three common detector architectures for the ARTM Tier 1 modulations: a symbol-by-symbol detector, a cross correlated trellis coded modulation (XTCQM) detector, and a continuous phase modulation (CPM) detector. We show that when used to detect Tier 1 modulations, these detectors perform well even without knowledge of the modulation used by the transmitter. The common symbol-by-symbol detector suffers a loss of 1.5 dB for SOQPSK-TG and 1.6 dB for FQPSK-JR in bit error rate performance relative to the theoretical optimum for these modulations. The common XTCQM detector provides a bit error rate performance that is 0.1 dB worse than optimum for SOQPSK-TG and that matches optimum performance for FQPSK-JR. The common CPM detector achieves a bit error rate performance that is 0.25 dB worse than optimum for SOQPSK-TG and that approximately matches optimum for FQPSK-JR. The common XTCQM detector provides the best bit error rate performance, but this detector also has the highest complexity.