Distributed fault-tolerant channel allocation for cellular networks

摘要

A channel allocation algorithm includes channel acquisition andnchannel selection algorithms. Most of the previous work concentrates onnthe channel selection algorithm since early channel acquisitionnalgorithms are centralized and rely on a mobile switching center (MSC)nto accomplish channel acquisition. Distributed channel acquisitionnalgorithms have received considerable attention due to their highnreliability and scalability. However, in these algorithms, a borrowernneeds to consult with its interference neighbors in order to borrow anchannel. Thus, the borrower fails to borrow channels when it cannotncommunicate with any interference neighbor. In real-life networks, undernheavy traffic load, a cell has a large probability to experience annintermittent network congestion or even a communication link failure. Innexisting distributed algorithms, since a cell has to consult with anlarge number of interference neighbors to borrow a channel, the failurenrate will be much higher under heavy traffic load. Therefore, previousndistributed channel allocation algorithms are not suitable for real-lifennetworks. We first propose a fault-tolerant channel acquisitionnalgorithm which tolerates communication link failures and node (MH ornMSS) failures. Then, we present a channel selection algorithm andnintegrate it into the distributed acquisition algorithm. Detailednsimulation experiments are carried out in order to evaluate our proposednmethodology. Simulation results show that our algorithm significantlynreduces the failure rate under network congestion, communication linknfailures, and node failures compared to nonfault-tolerant channelnallocation algorithms. Moreover, our algorithm has low message overheadncompared to known distributed channel allocation algorithms, andnoutperforms them in terms of failure rate under uniform as well asnnonuniform traffic distribution