Dynamic Power Management for the Iterative Decoding of Turbo Codes

Abstract : Turbo codes are presently ubiquitous in the context of mobile wireless communications among other application domains. A decoder for such codes is typically the most power intensive component in the base- band processing chain of a wireless receiver. The iterative nature of these decoders represents a dynamic workload. This brief presents a dynamic power management policy for these decoders. An algorithm is proposed to tune a power manageable decoder according to a prediction of the work- load involved within the decoding task. By reclaiming the timing slack left when operating the decoder at a high power mode, the proposed algorithm continuously looks for opportunities to switch to a lower power mode that guarantees the task completion. We apply this technique to an long term evolution Turbo decoder and explore the feasibility of a VLSI implementa- tion on a CMOS technology of 65 nm. Energy savings of up to 54% were achieved with a relatively low loss in error-correction performance.