Search

Proximity-awareness, that is, a mobile device being aware of the presence and capabilities of other devices in its proximity, can be beneficial in many frameworks that support spontaneous sharing of sensors available in advanced personal mobile devices (e.g., smartphones and tablets). Providing Quality of Service (QoS) guarantees in such frameworks is highly challenging because of the dynamic and loosely coupled nature of Mobile Ad Hoc Networks (MANETs). A framework called the SPontaneous Information and Resource sharing InfrasTructure (SPIRIT) has been presented before to address the challenges of proximity-aware mobile sensor sharing. SPIRIT allows mobile applications to share sensors as services in an automatic fashion by enabling the service providers and clients to express a variety of QoS specifications. This paper presents a set of mobility-aware QoS mechanisms for enabling the implementation of QoS specifications along themultihop paths between service providers and clients in highlymobile environments. Simulations in small-scale Mobile Ad Hoc Networks show SPIRIT's ability to effectively control and manage traffic flows while maintaining desired QoS. The implications of the proposed QoS mechanisms extend beyond the scope of SPIRIT, as QoS provisioning is an important issue in many MANET frameworks and applications including Vehicular Ad Hoc Networks (VANETs). [ABSTRACT FROM AUTHOR]

Abstract: The highly dynamic and uncertain character of mobile ad-hoc networks poses significant challenges for group management. Node mobility often changes the multicast tree, and therefore, frequent updates from group members are required to refresh the multicast tree at the source node. This paper presents Courier, a group communications algorithm that uses the location and velocity of roaming nodes to provide bandwidth efficient multicast between a source and its destinations (i.e., group members) in location aware mobile environments. Toward that end, Courier offers (1) a bandwidth efficient method for location updates from group members, (2) a mobility prediction model for predicting the movement of mobile group members, and (3) an overlay multicast data distribution tree (OMDDT) construction algorithm that is guided by the mobility prediction model. Comparisons of Courier to related multicast algorithms indicate an increase in data transmission success and a decrease in overall bandwidth consumption. [Copyright &y& Elsevier]

Abstract: Wireless multicast for multihop ad-hoc networks ensures that the same information is delivered efficiently to multiple recipients simultaneously. However, existing protocols ignore the real-time nature of many wireless applications such as real-time video and audio communications in mesh and ad-hoc networks. Further, devices in such networks are typically energy-constrained, i.e., multicast protocols have to trade off timeliness with energy efficiency. This paper presents RTMC, a real-time multicast protocol for wireless multihop networks that allows receivers to specify their individual real-time constraints and establishes multicast trees such that receivers’ deadlines are met and overall energy consumption in the network is reduced. Toward this end, RTMC relies on dynamically prioritized packet scheduling on forwarding nodes, prioritized channel access at the MAC layer, feedback control for latency management, tree adaptations to address mobility, dynamic subscriptions and unsubscriptions, and adaptations to address link breakages. Simulation results show that, compared to non-real-time multicast techniques, RTMC can provide user-specific latency management while reducing the energy consumption in the network. [Copyright &y& Elsevier]