MERLIN: A synergetic integration of MAC and Routing Protocol for Distributed Sensor Networks

Notoriously, energy-efficient MAC protocols cause
high latency of packets. Such delays may well increase when
a routing protocol is applied. Therefore, quantifying the endto-
end delay and energy consumption when low duty cycle
MAC and routing protocols are jointly used, is of particular
interest. In this paper, we present a comprehensive evaluation
of the MERLIN (MAC and Efficient Routing integrated with
support for localization) protocol. MERLIN integrates MAC and
routing features into a single architecture. In contrast to many
sensor network protocols, it employs a multicast upstream and
multicast downstream approach to relaying packets to and from
the gateway. Simultaneous reception and transmission errors
are notified by using asynchronous burst ACK and negative
burst ACK. A division of the network into timezones, together
with an appropriate scheduling policy, enables the routing of
packets to the closest gateway. An evaluation of MERLIN has
been conducted through simulation, against both the SMAC and
the ESR routing protocols,which is an improved version of the
DSR algorithm. The results illustrate how both SMAC and ESR,
jointly used in low duty cycle scenarios, can cause an impractical
and very high end-to-end delays. MERLIN, as an integrated
approach, notably reduces the latency, resulting in nodes that
can operate in a very low duty cycle. Consequently, an extension
of the operative lifetime of the sensor network is achieved.