ADAPTIVE VITERBI DECODER AND ITS OPERATIONAL METHOD

摘要

PURPOSE: An adaptive viterbi decoder and its operational method is provided to reduce current consumption and state metric memory. CONSTITUTION: An adaptive viterbi decoder and its operational method includes a Branch Metric Calculation unit(BMC)(110) that outputs a branch metric by calculating the approximation among pre-set code orders that can be output from the received data and an encoder. A State Metric Threshold Compare unit(SMTC)(120) compares a saved state metric with a pre-set threshold value and outputs the result. A State Metric Memory(SMM)(114) saves a state metric and survival or not of the state metric. An Add - Compare - Select unit(ACS)(112) operates selectively based on the comparison result and survival data output from the SMTC(120). The ACS(112) carries out addition, comparison and selection of the inputted and saved state metric in the SMM(114), and outputs a survival path of each state mostly approximate the transmitted code. The ACS(112) outputs a new state metric for the survival path and a new survival path for the new state metric. A Path Memory(PM)(116) saves the survival path output from the ACS(112). A Trace Back unit(TB)(118) finds a path mostly approximate to the transmitted data of the transmission encoder using the saved survival path and outputs a decoded data.