22-05-2012, 04:16 PM
Detection of Selfish Nodes in Networks Using
CoopMAC Protocol with ARQ
Detection of Selfish Nodes in Networks.pdf (Size: 538.15 KB / Downloads: 39)
INTRODUCTION
THE throughput of wireless networks can be significantly
increased by allowing cooperation among nodes [1] and
[2], which can be efficiently implemented in the medium
access control (MAC) layer, as shown for example by the
CoopMAC protocol [3], which provides a shorter response
time and a better integration with the physical layer than
traditional network layer routing [4]. However, a relay helps
other nodes at the expense of its own resources (energy
and time) that could otherwise be spared or used for the
transmission of its own packets. This burden is compensated
by the fact that a node operating as a relay in one transmission,
will in turn benefit from cooperation of other nodes in
another transmission. However, a node can still achieve a high
throughput while further sparing energy if it does not relay
other nodes’ packets while still exploiting their cooperation for
its own transmissions.
SYSTEM MODEL
We consider an ad hoc network implementing opportunistic
cooperation [21] among nodes by the CoopMAC protocol [3],
based on the IEEE 802.11 standard. In detail, the CoopMAC
protocol works as follows for a transmission from node