Digital Signal Processing Reference
In-Depth Information
Fig. 1
A typical WSN scenario
Compared to the traditional computer networks, WSNs have several unique
characteristics as listed in the following. A particular WSN installation might not
require all of these characteristics, but many useful classes of WSNs share most or
all of the properties described in this list.
Network size and density
: WSNs may consist of tens of thousands of nodes.
The density of nodes can be high, depending on the application requirements
for sensing coverage and robustness via redundancy.
Communication paradigm
: In WSNs, node identifiers are typically not important.
Instead, WSNs are
data-centric
, which means that messages are not send to
individual nodes but to geographical locations or regions based on the data
content.
Application specific
: A WSN is deployed to perform a specific task, e.g. envi-
ronmental monitoring, target tracking, or intruder alerting. As a result, the node
platforms and communication protocols are designed to optimal performance
on a certain application-dependent scenario. The application specific behavior
enables data aggregation, and in-network processing, and decision making.
Network lifetime
: WSNs are typically deployed to observe certain physical
phenomenon that range in duration from fractions of a second to a few months or
even several years. As replacing batteries is not feasible due to large network size
and deployment to possibly hazardous environment, nodes must optimize their
energy usage for network lifetime.
Low cost
: To allow cost effective deployment of a large number of nodes, the cost
of an individual sensor node should be minimized. Also, as recovering sensors
after deployment in some application scenarios may not be feasible, sensors
should be cheap enough to be considered disposable.
Resource constraints
: A typical WSN node combines low cost with small phys-
ical size and is battery powered. Thus, computation, communication, memory,
and energy resources are very limited.
