AxRMU-2^m: Higher m-bit Approximate Radix-2^m Multiplier Unit

This paper presents the design and evaluation of higher m-bit Approximate Radix-2^m Multiplier Units (AxRMU) with applications in error-tolerant systems. The AxRMU proposal architectures, specifically AxRMU-8 and AxRMU-16, incorporate approximation in generating partial products, reducing the number of logic gates and improving energy efficiency while maintaining acceptable accuracy. A case study using the statistically efficient and fast calibration (StEFCal) algorithm in radio astronomy demonstrates the performance of the AxRMUs in terms of energy, area savings, and computational accuracy. Results show that AxRMU designs outperform state-of-the-art approximate multipliers like DRUM, LoBA, and RoBA, achieving energy savings of up to 98.30% and area savings of up to 91.57%, with minimal mean square error (MSE) trade-offs. These findings highlight the potential of AxRMUs in balancing performance and resource efficiency for applications that can tolerate minor computational inaccuracies.