Patent ID: 7239667

Claim:
An 8 PSK (Phase Shift Keying) rotationally invariant encoding method, the method comprising: receiving a plurality of input bits; precoding the plurality of input bits thereby generating a plurality of precoded bits; encoding the plurality of precoding bits using Turbo Trellis Coded Modulation (TTCM) encoding thereby generating a plurality of encoded bits; selectively grouping encoded bits of the plurality of encoded bits into a plurality of 8 PSK symbols; mapping each 8 PSK symbol of the plurality of 8 PSK symbols to a corresponding constellation point within an 8 PSK constellation having an 8 PSK constellation mapping and a permutation that describes a 90 degree rotation of the 8 PSK constellation mapping; and generating an analog baseband signal whose I,Q (In-phase, Quadrature) components correspond to the mappings of the 8 PSK symbols to the constellation points within the 8 PSK constellation; and wherein: the precoding and the encoding operate cooperatively to provide rotational invariance of the 8 PSK symbols within the plurality of 8 PSK symbols that are mapped to the constellation points within the 8 PSK constellation; and the TTCM encoding employs a trellis whose state transitions via branch connectivity are governed by an induced permutation mapping of states of the trellis that accommodates the 90 degree rotation of the 8 PSK constellation mapping.