HPC machines are introducing more and more heterogeneity in their architecture on the road to exascale systems. The increasing complexity of the machines due to the variety of hardware architectures and accelerators makes efficient programming a task harder than ever. Heterogeneous parallel programming models, such as OmpSs@FPGA, help the programmer handle the most unfriendly parts of working with accelerators. This master thesis analyzes the OmpSs@FPGA communication system and proposes a set of techniques to overcome the problems related to it and potentially improve the performance of the applications. The results show that the techniques proposed speed up the applications under certain conditions and, most importantly, solves some of the limitations that had the previous communication system. In particular, the new techniques specially improve the explotation of fine-grain parallelism and open the door to explore new possibilities with regard to data communication and re-use. Moreover, a tool (autoVivado) that automatically manages the process of bitstream generation, from the synthesis of the HLS code to the generation of the device-tree, has been developed as part of this master thesis. autoVivado has been fully integrated with the OmpSs@FPGA compiler infrastructure, providing the programmers a way to transparently generate parallel heterogenous programs and bitstreams from OmpSs applications that use FPGA accelerators.