A Survey on Multimedia-Based Cross-Layer Optimization in Visual Sensor Networks

Visual sensor networks (VSNs) comprised of battery-operated electronic devices endowed with low-resolution cameras have expanded the applicability of a series of monitoring applications. Those types of sensors are interconnected by ad hoc error-prone wireless links, imposing stringent restrictions on available bandwidth, end-to-end delay and packet error rates. In such context, multimedia coding is required for data compression and error-resilience, also ensuring energy preservation over the path(s) toward the sink and improving the end-to-end perceptual quality of the received media. Cross-layer optimization may enhance the expected efficiency of VSNs applications, disrupting the conventional information flow of the protocol layers. When the inner characteristics of the multimedia coding techniques are exploited by cross-layer protocols and architectures, higher efficiency may be obtained in visual sensor networks. This paper surveys recent research on multimedia-based cross-layer optimization, presenting the proposed strategies and mechanisms for transmission rate adjustment, congestion control, multipath selection, energy preservation and error recovery. We note that many multimedia-based cross-layer optimization solutions have been proposed in recent years, each one bringing a wealth of contributions to visual sensor networks

Quality of services for remote control in High Energy Physics experiments: a case study

Abstract The development of new advanced applications and the evolution in networking are two related processes which greatly benefit from two-way exchanges and from progress in both fields. In this study we show how mission-oriented networked applications can be effectively deployed for research purposes if coupled to the support of Quality of Service (QoS) in IP networks. QoS is one of the latest research topics in network engineering. In this article we focus on two specific examples of networked applications: remote instrumentation control and remote display of analysis data when applied for the support of experiments in the high energy physics field. In this paper we focus on the application requirements: the availability of a reliable transmission channel, limited one-way delay for timely interactions between servers and clients and fairness in network resources allocation in case of contention. The above-mentioned requirements can be addressed through the support of QoS, i.e. through the differential treatment of packets on the end-to-end data path. Several technologies and protocols for QoS support in packet networks have been devised during the last years by the research community. In this study we focus on the Differentiated Services (diffserv) approach, an architecture characterized by high scalability, flexibility and interoperability. In this paper we identify the application requirements and we quantitatively specify the corresponding service profiles. The diffserv network architecture needed to support the services is defined in terms of functional blocks (policing, classification, marking and scheduling) and of their placement in the network. Finally, for each of them the configuration best suited to remote control support is defined

Dynamic Routing Framework for Wireless Sensor Networks

Numerous routing protocols have been proposed for wireless sensor networks. Each such protocol carries with it a set of assumptions about the trafï¬c type that it caters to, and hence has limited interoperability. Also, most protocols are validated over workloads which only form a fraction of an actual deployment’s requirement. Most real world and commercial deployments, however, would generate multiple trafï¬c types simultaneously throughout the lifetime of the network. For example, most deployments would want all of the following to happen concurrently from the network: periodic reliable sense and disseminate, real time streams, patched updates, network reprogramming, query-response dialogs, mission critical alerts and so on. Naturally, no one routing protocol can completely cater to all of a deployments requirements. This chapter presents a routing framework that captures the communication intent of an application by using just three bits. The traditional routing layer is replaced with a collection of routing components that can cater to various communication patterns. The framework dynamically switches routing component for every packet in question. Data structure requirements of component protocols are regularized, and core protocol features are distilled to build a highly composable collection of routing modules. This creates a framework for developing, testing, integrating, and validating protocols that are highly portable from one deployment to another. Communication patterns can be easily described to lower layer protocols using this framework. One such real world application scenario is also investigated: that of predictive maintenance (PdM). The requirements of a large scale PdM are used to generate a fairly complete and realistic trafï¬c workload to drive an evaluation of such a framework