A 410GFLOP/s, 64 RISC-V Cores, 204.8GBps Shared-Memory Cluster in 12nm FinFET with Systolic Execution Support for Efficient B5G/6G AI-Enhanced O-RAN
Yichao Zhang, Marco Bertuletti, Sergio Mazzola, Samuel Riedel, Luca Benini
Published: 2025/9/10
Abstract
We present HeartStream, a 64-RV-core shared-L1-memory cluster (410 GFLOP/s peak performance and 204.8 GBps L1 bandwidth) for energy-efficient AI-enhanced O-RAN. The cores and cluster architecture are customized for baseband processing, supporting complex (16-bit real&imaginary) instructions: multiply&accumulate, division&square-root, SIMD instructions, and hardware-managed systolic queues, improving up to 1.89x the energy efficiency of key baseband kernels. At 800MHz@0.8V, HeartStream delivers up to 243GFLOP/s on complex-valued wireless workloads. Furthermore, the cores also support efficient AI processing on received data at up to 72 GOP/s. HeartStream is fully compatible with base station power and processing latency limits: it achieves leading-edge software-defined PUSCH efficiency (49.6GFLOP/s/W) and consumes just 0.68W (645MHz@0.65V), within the 4 ms end-to-end constraint for B5G/6G uplink.