Report ID
2008-14
Report Date
Abstract
A wireless sensor network (WSN) is comprised of resource
constrained devices called motes. Motes are
battery operated and must conserve as much power
as possible. Power usage for each mote is made up of
processing data, sensing the surroundings, and sending
and receiving packets. The bulk of power usage
for standard WSN applications lies in the radio where
receiving and sending packets are necessary to communicate
to a base station (as much as 80%) [5]. This
communication is generally greater than the range of
any single mote, and thus multi-hop routing must
take place. The multi-hop routing furthers the need
for reduction of packets because each additional hop
adds to the amount of traffic generated. By compressing
sense data, which each mote collects, the number
of packets can be reduced. Only lossless compression
is taken into consideration. This paper proposes a
solution to reduce the consumption of power using
reconfigurable hardware specially programmed to do
low power compression. A mote would offload bulk
data to a hardware attachment and receive the compressed
version of the data. The compressed data can
be stored in flash or sent over the network to the sink
node. Additional work will go into the trade-off factor
between compression to non-compression. Compression
should only occur if the amount of power
taken to compress X amount of bytes and transfer
Y amount of bytes is less than just transferring X
amount of bytes. Moreover, seeing the gains from
doing offloading of compression versus doing it onchip
must be taken into consideration as well. Additional
hardware is not free, so cost for the power savings
plays a factor in deciding how compression takes
place. Moreover, there are also limitations based on
the kind of reconfigurable hardware. This paper addresses
these issues.
Document
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