Cryptography Reference
In-Depth Information
1.6.2 Differences Between MANET and WSN
One of the fundamental differences between MANET and WSN is that MANET
nodes (PDA, laptop computers, cell phones, and other mobile radio terminals) are
in close association with human beings. However, sensor nodes are in close proxim-
ity to the surrounding environment. Consequently, sensor nodes are more scalable
than MANET nodes, and can range from a few hundreds to thousands of nodes.
Deployment scenarios are as diverse as sensor nodes placed on the edge of an active vol-
cano or in the middle of an ocean bed. Therefore the likelihood of sensor nodes being
damaged is higher when compared to MANET nodes. For this reason, the topology of
WSN is very dynamic and is not solely dependent on the node mobility, as in MANET.
Hence, the topology of the network is also dependent on the sleep/awake cycle. Sensor
nodes have ROM memory of a few kilobytes and processing speeds of a few megahertz.
On the other hand, MANET nodes have large storage space and high-speed processors
that can record and play video files.
1.7 Challenges in WSN
In general, WSN pose significant technical challenges to communication, data pro-
cessing, and security. (Threats to security will be discussed in detail in Chapter 2.)
Moreover, harsh and dynamic operating environments, along with energy and band-
width constraints, have increased challenges to node/network discovery, routing,
data aggregation, querying, and network management. Below, we discuss a few of
these challenges.
1.7.1 Battery Life and Power Consumption
The need for power control to increase energy efficiency has been one of the main
challenges in WSN. Usually, sensor nodes are battery-operated but function in perilous
environments, making frequent replacement of batteries difficult. It is important for
sensor nodes to monitor battery life, as there is a possibility of the node receiving high
current that lasts for a long duration, resulting in rapid depletion of the battery. Hence,
caution should be exercised by periodica lly shutting down the node when it is not in the
active routing path or during sensing and processing operations. Another technique is
to use complex data processing techniques to reduce battery consumption.
The network life is heavily dependent on the battery life, and the need for new
energy efficient schemes that take every layer of the sensor node into consideration has
been a foremost challenge in WSN. In addition, predicting the necessary power level
for transmitting control and data packets is quite complex. The sensor's power level
directly affects the transmission range, thus changing the routing path. For example,
if a neighboring node is damaged, the transmitting sensor node should transmit at a
higher power level, thus reducing its battery life and reducing its chances of participat-
ing in any further intermediate routing operations. Lower power levels can lead to
Search WWH ::
Custom Search