A simplified computational kernel for trellis-based decoding

A simplified branch metric and add-compare-select (ACS) unit is presented for use in trellis-based decoding architectures. The simplification is based on a complementary property of best feedforward and some systematic feedback encoders. As a result, one adder is saved in every other ACS unit. Furthermore, only half the branch metrics have to be calculated. It is shown that this simplification becomes especially beneficial for rate 1/2 convolutional codes. Consequently, area and power consumption will be reduced in a hardware implementation.