Challenges and a solution to support QoS for real-time traffic in multi-hop ad-hoc networks

In this paper we explain why trivial solutions are inadequate for supporting deterministic QoS (quality of service) for real-time traffic in multi-hop ad-hoc networks with shared medium and contention based MAC (media access control) protocols. We also provide our initial work to address this issue with an analytical model within the context of suburban ad-hoc networks (SAHN). A SAHN is a multi-hop ad-hoc network. The analytical model is based on the channel access mechanism of a contention based MAC protocol such as the IEEE 802.11e. We refer to the improved IEEE 802.11e as SAHN-MAC. SAHN-MAC provides a distributed admission control and bandwidth reservation scheme by extending the features of IEEE 802.11e and coordinating with the network layer. The proposed admission control mechanism aims to prevent any new data stream from initiating if the new stream saturates or is about to saturate any part of the network. The bandwidth reservation scheme is necessary for the admission control scheme to work properly. These unique features make SAHN-MAC different from existing protocols. The proposed mechanisms have been verified via simulations.