What is Cross-layer Optimization

In this chapter, the practical and experimental aspects of medium access control protocol design for wireless sensor networks are discussed. We outline the basic design principles of medium access control procedures and the general development trends from the perspective of real world implementations. We take into account especially energy consumption and latency requirements. We share our experiences gained in practical research and pre-commercial projects, wherein we have been tackling issues such as traffic awareness, coexistence of different protocols, spectrum agility for wireless sensor networks and porting of MAC-layers to different platforms. The contemporary focuses on medium access control design such as cross-layer approaches, multi-radio based protocols and radio wake-up based medium access solutions are also covered in this chapter.