Abstract:
This paper proposes a backup path management method for time division
multiple access (TDMA) based client wireless mesh networks (WMNs). In a TDMA based
client WMN, as links/nodes fail or as nodes perform handover and as flows enter and leave
the network, the paths between various nodes change as well as the bandwidth available
along these paths. In these networks, to support the quality of service requirements of
flows, backup paths with the required bandwidth need to be established dynamically. Some
methods are proposed in the literature to establish backup paths which handle link/node
failures and node handover in ad hoc networks, but none of these methods can provide
backup paths with the required bandwidth dynamically. To address that issue, the present
paper proposes a backup path management method which is adaptive to both topological
changes and traffic changes in a network. Each node along the current path between a
source and a destination finds backup paths with the required bandwidth in order to handle
failure of the link to its downstream node and its own failure or handover. Nodes use twohop
neighborhood information and slots status information of two-hop neighbors to
establish backup paths. We prove that the number of backup paths available when a node
N searches for backup paths to handle its own failure are more than the number of backup
paths available when some other node searches for the backup paths for the failure of node
N. Performance of the proposed method is compared with the performance of a naive path
management (NPM) method in which always the source establishes backup paths whenever
a link/node fails or a node performs handover, and also with the performance of a
backup path management method proposed in the literature. The proposed method significantly
outperforms the NPM method and the method selected from the literature. For
example, when the speed of the mobile nodes is 50 m/s, the packet delivery ratio with the
proposed method is 63 % more than the NPM method and 35 % more than the method
selected from the literature.