An Effective Capacity Estimation Scheme in IEEE802.11-based Ad Hoc Networks

ABSTRACT Capacity estimation is a key component of any admission control scheme required to support quality of service provision in mobile ad hoc networks. A range of schemes have been previously proposed to estimate residual capacity that is derived from window-based measurements of channel estimation. In this paper a simple and improved mechanism to estimate residual capacity in IEEE802.11-based ad hoc networks is presented. The scheme proposes the use of a 'forgiveness' factor to weight these previous measurements and is shown through simulation-based evaluation to provide accurate utilizations estimation and improved residual capacity based admission control

Link Quality and MAC-Overhead aware Predictive Preemptive Multipath Routing Protocol for Mobile Ad hoc Networks

In Ad Hoc networks, route failure may occur due to less received power, mobility, congestion and node failures. Many approaches have been proposed in literature to solve this problem, where a node predicts pre-emptively the route failure that occurs with the less received power. However, these approaches encounter some difficulties, especially in scenario without mobility where route failures may arise. In this paper, we propose an improvement of AOMDV protocol called LO-PPAOMDV (Link Quality and MAC-Overhead aware Predictive Preemptive AOMDV).  This protocol is based on new metric combine two routing metrics (Link Quality, MAC Overhead) between each node and one hop neighbor. Also we propose a cross-layer networking mechanism to distinguish between both situations, failures due to congestion or mobility, and consequently avoiding unnecessary route repair process. The LO-PPAOMDV was implemented using NS-2. The simulation results demonstrate the merits of our proposed LO-PPAOMDV with approximately 10-15% increase in the packet delivery ratio while average end-to-end delay is reduced by 20%, and normalized routing load is reduced about 45%, also with 7% increase in the throughput, when compared with PPAOMDV

QoS-aware Multipath Routing Scheme for Mobile Ad Hoc Networks

 Providing Quality of Service (QoS) support in Mobile Ad Hoc Networks (MANETs) is a particularly active research area with a number of proposals being made to support real-time applications that are based upon the interaction between the routing scheme and a QoS provisioning mechanism. This paper builds upon such ideas and presents QoS-aware Shortest Multipath Source (Q-SMS) routing scheme that have been shown to offer significant network improvement when compared to previously proposed schemes. Q-SMS essentially modifies the previously proposed SMS scheme to explicitly provide QoS assurance. The new proposed scheme allows nodes to obtain and then use estimation of the residual capacity to make appropriate admission control decisions. The performance differentials are investigated using Network Simulator 2 (NS-2). Results demonstrate the merits of the proposed scheme with a 16% increase in goodput while end-to-end delay is reduced by 37% when compared with SMS and the necessity of QoS-aware multipath routing schemes in MANETs becomes more apparent