Using a modified Wei method, originally designed for additive white Gaussia
n noise (AWGN) channels, we have constructed four-dimensional (4-D) and six
-dimensional (6-D) trellis codes with rectangular signal constellations for
frequency-nonselective mobile radio channels, Applying a novel way of part
itioning the two-dimensional (2-D) constituent constellations, both into su
bsets with enlarged minimum Euclidean distance and subrings including equal
energy signal points, we have obtained partitions of the 2N-D signal sets
into subsets with a Hamming distance between signal points which equals N.
This is fundamental for constructing good trellis codes to transmit data ov
er flat fading channels.