Typically, the objective of a
sensor network is monitoring a certain signal of interest, and informing a central
base station or a sink about the activity in the region that is being sensed.
Since a sensor network is deployed for achieving a certain system-wide goal,
8
nodes collaborate instead of competing with each other. For example, if the
communication range of each node is limited, the nodes may use multi-hop
communication to send their data to the sink. This requires a routing strategy
that ensures that the battery energy as well as the throughput are optimized
in such a way that the duration of the correct functioning of the entire network,
i.e., the network lifetime, is maximized. Thus the nodes collaborate to
optimize a system-wide objective. This is unlike other wireless networks such
as wireless local area networks (wireless LANs) where the nodes (users) are
greedy, and their primary objective is maximizing their own gains.
3.2 Network Scale
While some sensor network applications involve a small number of sensors
(10-20), most exciting applications require a large number of sensor nodes
(100-1000) [2]. The basic premise being that because of redundancy, a network
consisting of a large number of sensor nodes is more robust to node
failure than a network consisting of a fewer number of nodes. Developments
in integrated circuit design technology are expected to make the mass production
of sensor devices relatively inexpensive, and hence such large sensor
networks are likely to be common.
Pages:
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48