Design Space Exploration For Hardware-Efficient Stochastic Computing: A Case Study On Discrete Cosine Transformation

In recent years stochastic computing (SC) is re-gaining increasing attention for its unique advantages on low hardware cost and strong error resilience that are the key metrics for nanoscale CMOS era. However, the potential deployment of SC in practical applications is impeded by the long latency of sequential bit-stream and large complexity of pseudo random number generator (PRNG). Aiming to mitigate these challenges, this paper exploits the design space for hardware-efficient stochastic computing with a case study on 4-point discrete cosine transformation (DCT). First, an efficient compensation mechanism is proposed to solve the scaling problem of SC system. Then, two approaches, namely Splitting-Shuffling (SS) and PRNG sharing techniques are proposed to reduce the overall area and processing latency, respectively. Analysis results show that, sustaining the same computing accuracy, the joint use of the proposed approaches leads to 44% reduction in area and 49% reduction on latency than conventional SC design, respectively.