Tham khảo tài liệu 'emerging communications for wireless sensor networks part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 2 Wireless Sensor Networks Applications via High Altitude Systems Zhe Yang and Abbas Mohammed Blekinge Institute of Technology Sweden 1. Introduction Wireless sensor networking is a fast emerging subfield in the field of wireless networking. It is a key technology for the future ad has been identified as one of the most important technologies for this century Akyildiz et al. 2002 Business Week 1999 Technology Review 2003 . These sensors are generally equipped with data processing communication and information collecting capabilities. They can detect the variation of ambient conditions in the environment surrounding the sensors and transform them into electric signal . temperature sound image . Interests in sensor networks have motivated intensive research in the past few years emphasizing the potential of collaboration among sensors in data collecting and processing coordination and management of the sensing activity and date flow to the sink. Depending on application to reveal some characteristics about phenomena in the area sensor nodes can be deployed on the ground in the air under water on bodies in vehicles and inside buildings Akyildiz et al. 2002 . Thus these connected sensor nodes have many promising applications in many fields . consumer military health environment security . Deployment of these sensor nodes can be in random fashion like dropping from a helicopter a disaster management setup or manual deploying nodes in a building to detect the movement of human Akyildiz et al. 2002 . Sensor nodes are usually constrained in energy and bandwidth Akyildiz et al. 2002 . Such constraints combined with the deployment of a large number of sensor nodes are challenges to the design and maintenance of sensor networks. Energy-awareness has to be considered at all layers of networking protocol stack. It is also related to physical and link layers which are generally common for all kind of sensor applications. Research on these layers has been focused on radio .
