MODULATION MED EN APSK-KONSTELLATION MED ÉN RING MED UREGELMÆSSIGT PLACEREDE PUNKTER

The present invention relates to a receiver for a digital communication system comprising a demodulator arranged for demodulating a received signal into a sequence of digital symbols, wherein the digital symbols belong to a multi-ring digital signal constellation (200, 201, 202, 203), which has all signal points placed on at least two concentric rings (200, 201, 202, 203), whereby: a) the total number of signal points is larger than 8, b) at least one ring has unequally spaced points (201), and c) the at least one ring with unequally spaced signal points is constructed to form together with at least one neighbouring ring a subset of neighbouring rings (202), whereby each signal point of the subset has a unique angular coordinate modulo 2À and whereby the angular spacing of the signal points of the subset is uniform.