A hexagonal-tree TDMA-based QoS multicasting protocol for wireless mobile ad hoc networks

The mobile multimedia applications have recently generated much interest in wireless ad hoc networks with supporting the quality-of-service (QoS) communications. The QoS metric considered in this work is the reserved bandwidth, i.e., the time slot reservation. We approach this problem by assuming a common channel shared by all hosts under a TDMA (Time Division Multiple Access) channel model. In this paper, we propose a new TDMA-based QoS multicast routing protocol, namely hexagonal-tree QoS multicast protocol, for a wireless mobile ad hoc network. Existing QoS routing solutions have addressed this problem by assuming a stronger multi-antenna model or a less-strong CDMA-over-TDMA channel model. While more practical and less costly, using a TDMA model needs to face the challenge of radio interference problems. The simpler TDMA model offers the power-saving nature. In this paper, we propose a new multicast tree structure, namely a hexagonal-tree, to serve as the QoS multicasting tree, where the MAC sub-layer adopts the TDMA channel model. In this work, both the hidden-terminal and exposed-terminal problems are taken into consideration to possibly exploit the time-slot reuse capability. The hexagonal-based scheme offers a higher success rate for constructing the QoS multicast tree due to the use of the hexagonal-tree. A hexagonal-tree is a tree whose sub-path is a hexagonal-path. A hexagonal-path is a special two-path structure. This greatly improves the success rate by means of multi-path routing. Performance analysis results are discussed to demonstrate the achievement of efficient QoS multicasting.