  The inefficiency of the fundamental access method of the IEEEE 802.11
standard is a well-known problem in scenarios where multiple long range and
faulty links compete for the shared medium. The alternatives found in the
literature are mostly focused on point-to-point and rarely on long range links.
Currently, there is no solution optimized for maritime scenarios, where the
point-to-multipoint links can reach several tens of kilometers, while suffering
from degradation due to the harsh environment. This paper presents a novel MAC
protocol that uses explicit signalling messages to control access to the medium
by a central node. In this solution, this role is played by an Access Point
that sends token messages addressed to each associated station, which is
granted exclusive access to the medium and assigned a number of credits; after
sending its own packets (if any), a station must release control of the token.
Simulation results show that this mechanism has superior performance in
point-to-multipoint, long range and faulty links, allowing a fairly and more
efficient usage of the shared resources among all nodes.
