In this paper, error resilience is achieved by adaptive, application-layer rateless channel coding, which is used to protect H.264/Advanced Video Coding (AVC) codec data-partitioned videos. A packetization strategy is an effective tool to control error rates and, in the paper, source-coded data partitioning serves to allocate smaller packets to more important compressed video data. The scheme for doing this is applied to real-time streaming across a broadband wireless link. The advantages of rateless code rate adaptivity are then demonstrated in the paper. Because the data partitions of a video slice are each assigned to different network packets, in congestion-prone wireless networks the increased number of packets per slice and their size disparity may increase the packet loss rate from buffer overflows. As a form of congestion resilience, this paper recommends packet-size dependent scheduling as a relatively simple way of alleviating the buffer-overflow problem arising from data-partitioned packets. The paper also contributes an analysis of data partitioning and packet sizes as a prelude to considering scheduling regimes. The combination of adaptive channel coding and prioritized packetization for error resilience with packet-size dependent packet scheduling results in a robust streaming scheme specialized for broadband wireless and real-time streaming applications such as video conferencing, video telephony, and telemedicine. Full article

Nodes in mobile ad hoc networks (MANETs) are mandated to utilize their limited energy resources in forwarding routing control and data packets for other nodes. Since a MANET lacks a centralized administration and control, a node may decide to act selfishly, either by refusing to respond to route requests from other nodes or deceitfully by responding to some route requests, but dropping the corresponding data packets that are presented for forwarding. A significant increase in the presence of these misbehaving nodes in a MANET can subsequently degrade network performance. In this paper, we propose a dynamic reputation management system for detecting and isolating misbehaving nodes in MANETs. Our model employs a novel direct monitoring technique to evaluate the reputation of a node in the network, which ensures that nodes that expend their energy in transmitting data and routing control packets for others are allowed to carry out their network activities while the misbehaving nodes are detected and isolated from the network. Simulation results show that our model is effective at curbing and mitigating the effects of misbehaving nodes in the network. Full article