Ubiquitous Sensor Networks - Application and Multidisciplinary Aspects of Wireless Sensor Networks - page 255

Because of the great number of constraints and the application field specifics,
the main USN challenges today are mostly concentrated on sensor network itself.
These issues and challenges can be grouped in [ 2 ]:
• Autonomous setup and maintenance : Sensor nodes are randomly deployed
and need to be maintained without any human intervention
• Infrastructure-less : All routing and maintenance algorithms need to be
distributed
• Energy-conscious design : The microcontroller, Operating System, communica-
tion protocols, and application software should be designed to conserve power
• Global time synchronization : Sensor nodes need to synchronize with each
other in a completely distributed manner for communication synchronization,
temporal ordering of detected events, and elimination of redundant events/
messages
• Dynamic topology due to failures or power-down/up
• Real-time and secure communication
Along with the tendency of minimization in physical size of sensor nodes and other
application-specific constraints, the given aims should more strictly be followed
only in limited number of the very demanding applications (such as battlefield
surveillance and monitoring, etc.). However, most of the typical implementations
today are deployed using small-scale ad hoc networks based on tree or cluster tree
topologies where some of the nodes do not need to be battery supplied. Within this
context, many ubiquitous industrial, environmental, healthcare, and other systems
are already widely deployed [ 3, 4 ].
References
1. ITU-T Technology Watch Breifing Report Series (2008) Ubiquitous sensor networks,
No.4, Feb 2008
2. Choi L (2007) Ubiquitous networks: sensor networks, computer system lab . Fall
3. Katsumi T, Kenji K (2006) Ubiquitous sensor network system. NEC Tech J 1:78-82
4. Mukhopadhyay S, Gaddam A, Gupota G (2008) Wireless sensors for home care monitoring - a
review. Bentham Science Publishers Ltd. pp 32-39