A scalable mutual exclusion algorithm for mobile ad hoc networks

Mobile ad hoc networks (MANETs) introduce new challenges to designing algorithms for solving the distributed mutual exclusion (MUTEX) problem. In this paper we propose the first permission-based MUTEX algorithm for MANETs. In order to reduce the messages cost, the algorithm uses the so called "look-ahead" technique, which enforces MUTEX only among the hosts currently competing for the critical section (CS). We propose mechanisms to handle the "doze" mode and "disconnection" of mobile hosts. The constraint of FIFO channel, which is not feasible in MANETs, is also relaxed. Using timeout, a fault tolerance mechanism is introduced to tolerate transient link and host failures. The simulation results show that the proposed algorithm works well under various mobility levels, load levels and system scales, especially when the mobility is high or load level is low. It is also shown that the algorithm has good scalability, especially when most of the requests come from a few active hosts.