Software-Defined Radio (SDR) represents a move from dedicated hardware to software implementations of digital communication standards. This approach offers flexibility, shorter time to market, maintainability , and lower costs, but it requires an optimized distribution tasks in order to meet performance requirements. Thus, we study the problem of scheduling SDR linear task chains of stateless and stateful tasks for streaming processing. We model this problem as a pipelined workflow scheduling problem based on pipelined and replicated parallelism on homogeneous resources. We propose an optimal dynamic programming solution and an optimal greedy algorithm named OTAC for maximizing throughput while also minimizing resource utilization . Moreover, the optimality of the proposed scheduling algorithm is proved. We evaluate our solutions and compare their execution times and schedules to other algorithms using synthetic task chains and an implementation of the DVB-S2 communication standard on the AFF3CT SDR Domain Specific Language . Our results demonstrate how OTAC quickly finds optimal schedules, leading consistently to better results than other algorithms, or equivalent results with fewer resources.

Optical flow estimation is used in many embedded computer vision applications, and it is known to be computationally intensive. In the literature, many methods exist to estimate optical flow. Thus, the challenge is to find a method that matches the applicative constraints. In an embedded system, a trade-off between power consumption and execution time has to be made to meet both energy and framerate constraints. This work proposes methods to implement an approximate Horn & Schunck optical flow estimation that meets embedded CPUs constraints. This is achieved thanks to architectural optimizations, software optimizations and algorithm tuning. For instance, on the NVIDIA Jetson Nano, and for HD video sequences, the achieved frame latency is 12 ms for 5 Watts. To the best of our knowledge, this is the fastest optical flow implementation on embedded CPUs.

Summary This article presents a new Domain Specific Embedded Language (DSEL) dedicated to Software‐Defined Radio (SDR). From a set of carefully designed components, it enables to build efficient software digital communication systems, able to take advantage of the parallelism of modern processor architectures, in a straightforward and safe manner for the programmer. In particular, proposed DSEL enables the combination of pipelining and sequence duplication techniques to extract both temporal and spatial parallelism from digital communication systems. We leverage the DSEL capabilities on a real use case: a fully digital transceiver for the widely used DVB‐S2 standard designed entirely in software. Through evaluation, we show how proposed software DVB‐S2 transceiver is able to get the most from modern, high‐end multicore CPU targets.