Variable wordlength soft-decision Viterbi decoder for power-efficient wireless LAN

This paper describes the design of a new, variable wordlength, soft-decision Viterbi decoder that can significantly reduce power dissipation in wireless local area network (LAN) hardware. By taking into account the dynamic range of the time-varying channel coefficients, the quantization level is adjusted to suit the observed instantaneous link quality, i.e., the decoder wordlength is adjusted to maintain efficient throughput requirements and low power dissipation. A dynamic voltage scaling is applied with a variable wordlength to significantly reduce power consumption in the soft-decision Viterbi decoder. Unlike the conventional 8-bit fixed-wordlength decoder, our radix-4 Viterbi decoder can reduce power consumption by up to 35% under AWGN and multipath fading channel conditions. ► We design a variable wordlength soft-decision Viterbi decoder for power-efficient wireless LAN. ► The variable wordlength is determined based on dynamic range in metric weighting value. ► The wordlength control scheme leads to maintain efficient performance requirements. ► Dynamic voltage scaling is applied with a variable wordlength circuit to significantly reduce power consumption. ► Unlike the conventional fixed-wordlength decoder, our Viterbi decoder can reduce power by up to 35%.