Wireless Sensor Networks : Technology, Protocols, and Applications

270 NETWORK MANAGEMENT FOR WIRELESS SENSOR NETWORKS
(5) locations stimulate the creation of new applications; (6) sensor nodes that move
can be controlled through knowledge of their location; and (7) for applications with
low-level naming and/or data-centric WSNs, knowledge of location information is
absolutely necessary.
Although global positioning systems (GPSs) can provide precise location information,
deployment of a GPS receiver in every sensor node is expensive and unaffordable
for most WSN applications. Non-GPS localization schemes are more
practical for WSNs. The existing non-GPS approaches are either hardware or topology
dependent [9.17]. Hardware-dependent algorithms need sensor hardware to
provide information such as signal strength. Topology-dependent algorithms for
localization do not need hardware support but do require support from special
‘‘seed nodes,’’ with exact knowledge of their location.
On the other hand, localization algorithms can be classified into centralized and
distributed schemes. In the centralized scheme, sensor nodes send control messages
to a central node whose location is known. The central node then computes the
location of every sensor node and informs the nodes of their locations. In the distributed
scheme, each sensor node determines its own location independently. The
distributed localization can be further grouped into range-based and range-free
schemes. In the range-based approach, some range information, such as time of
arrival, angle of arrival, or time difference of arrival is required. The range-free
algorithms works as follows: Several seed nodes are distributed in WSNs. Seed
nodes know their own locations, and they periodically broadcast a control message
with their location information. Sensor nodes that receive these control messages
can then estimate their own locations.
9.7 CONCLUSION
In this chapter we discussed network management for wireless sensor networks,
including traditional network management models such as SNMP and TOM.
Then issues and requirements of network management system for WSNs were identified.
Finally, an overview of MANNA as an example of NM for WSN was provided.
Management functions provide a major challenge to the design of WSN NM.
This includes an effective and practical management architecture, an effective MIB,
and an approach to utilize network management to increase productivity. The final
objectives of management are to prolong the life span of WSNs and to guarantee
the performance of their applications.
REFERENCES
[9.1] F. Wang, Q. Tian, Q. Gao, Q. Pan, ‘‘A Study of Sensor Management Based on Sensor
Networks,’’ Proceedings of the 2003 IEEE International Conference on Robotics,
Intelligent Systems and Signal Processing, Changsha, China, Oct. 2003, pp. 1058–1062.