This paper presents measures of performance of simplex signaling in a circu
lar trellis-coded modulation (CTCM) scheme. Background is given on both CTC
M and simplex signaling. The CTCM system is shown to give substantial codin
g gain when compared to conventional BPSK. Performance is also shown to imp
rove as trellis size increases. (C) 2001 Academic Press.