Block-coded modulation optimized for finite error rate on the white Gaussian noise channel

This correspondence examines the performance of block-coded modulation (BCM) at finite decoded bit error rates (BER). We consider the optimum geometric structure to optimize coding gain at finite BER, rather than asymptotic coding gain. We introduce the concept of the "row BER" and show that this structure may be implemented by a BCM scheme in which the row bit-error rates are equalized. We present a design procedure for such schemes, and show that significant improvements over conventional schemes are possible.