Dual-Layer Adaptive Error Control for Network-on-Chip Links

In this work, we present a new error control method to improve the energy efficiency and reliability of network-on-chip (NoC) links. The proposed method combines the error control coding (ECC) capabilities of the NoC´s datalink and network layers to dynamically adjust the error control strength in variable noise conditions. Network-layer ECC is used in low noise conditions and error control strength is enhanced by adding datalink-layer ECC in high noise regions. To switch between the two ECC modes at runtime without interrupting normal operation, we propose a dual-layer cooperative error control protocol and its hardware-efficient implementation using the concept of product codes. Theoretical analyses of residual error rate and performance show the proposed method outperforms previous single-layer fixed and adaptive error control schemes. Compared to previous solutions, the proposed method reduces residual packet error rate by up to four orders of magnitude, achieves up to 72% energy reduction and improves average latency by up to 64%. The energy and latency reduction benefits are maintained as the routing path length and packet size increase, at the cost of a moderate increase in area overhead.