RAMAN: Resource-efficient ApproxiMate Posit Processing for Algorithm-Hardware Co-desigN
Mohd Faisal Khan, Mukul Lokhande, Santosh Kumar Vishvakarma
TL;DR
RAMAN tackles the challenge of resource-constrained edge AI by introducing a resource-efficient approximate $Posit(8,2)$ MAC (REAP) and a scalable Vector Execution Unit. Through an algorithm-hardware co-design framework with approximation-aware training, RAMAN balances hardware efficiency with application accuracy, demonstrated on FPGA and ASIC with substantial resource savings and strong MNIST accuracy. Key contributions include the REAP MAC, a modular VEU that enables reuse across diverse workloads, and a quantization-aware training workflow validated via Tiny-YOLOv3. This work offers a practical path toward high-density, energy-efficient edge accelerators that maintain robust learning performance under hardware approximation.
Abstract
Edge-AI applications still face considerable challenges in enhancing computational efficiency in resource-constrained environments. This work presents RAMAN, a resource-efficient and approximate posit(8,2)-based Multiply-Accumulate (MAC) architecture designed to improve hardware efficiency within bandwidth limitations. The proposed REAP (Resource-Efficient Approximate Posit) MAC engine, which is at the core of RAMAN, uses approximation in the posit multiplier to achieve significant area and power reductions with an impact on accuracy. To support diverse AI workloads, this MAC unit is incorporated in a scalable Vector Execution Unit (VEU), which permits hardware reuse and parallelism among deep neural network layers. Furthermore, we propose an algorithm-hardware co-design framework incorporating approximation-aware training to evaluate the impact of hardware-level approximation on application-level performance. Empirical validation on FPGA and ASIC platforms shows that the proposed REAP MAC achieves up to 46% in LUT savings and 35.66% area, 31.28% power reduction, respectively, over the baseline Posit Dot-Product Unit (PDPU) design, while maintaining high accuracy (98.45%) for handwritten digit recognition. RAMAN demonstrates a promising trade-off between hardware efficiency and learning performance, making it suitable for next-generation edge intelligence.
