The present paper presents the ongoing research under FP7 ICT-AGRI “STRATOS” project. The previous research has identified the direction for further research and highlighted several problems that should be solved. The current research focuses on radio signal interference decrease and TDMA timing synchronization. Also the system architecture is specified in detail in the article, and specific devices are considered for prototype construction. Tests have shown that the proposed solutions decrease TDMA frame jitter six times and allow interference-free coexistence of sensor network and Wi-Fi devices.