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• Automated mechanism for configuring node radio parameters at run-time. • Distributed mechanism, primarily on nodes, reduces communication overhead. • Responds dynamically to both internal and external changes in network environment. • Supports multiple application requirements simultaneously. Advanced wireless communication technologies are leading towards large-scale, geographically distributed systems, which consist of thousands of co-existing devices with potentially conflicting application requirements, such as high data delivery ratio and low power consumption. At the same time, devices are challenged by varying environmental conditions, which can also lead to degradation in network performance. To ensure the overall network performance and service stability offered by individual devices, the devices must co-exist and adapt to changes in their surrounding environment. In this paper, an application-aware adaptive method is proposed to allow individual devices to dynamically and automatically decide and configure its communication parameters according to its application requirements and environmental conditions. The algorithm aims to enhance and maintain the network performance over time, while allowing every device to satisfy its application requirements. The algorithm is realised on the modern LoRaWAN network protocol. Simulated experiments confirm the proposed algorithm's ability to adapt to changing application requirements at runtime while maintaining network performance. They demonstrate an improvement in packet delivery ratio, energy consumption, and the novel ability to respond to an application's individual performance requirements. [ABSTRACT FROM AUTHOR]

Abstract: Wireless mesh networking is an economic and convenient way to provide last mile Internet access through ad hoc peer-to-peer communication links. However, without systematic network configuration and channel resource management, these networks suffer from scalability, performance degradation and service disruption issues due to overwhelming co-channel interference, unscrupulous channel utilization and inherent network mobility. The IEEE 802.11 DCF and EDCA mechanisms based on CSMA/CA are the most widely used random channel access mechanisms, but unfortunately these cannot effectively eliminate hidden terminal and exposed terminal problems in multi-hop scenarios. Social network analysis techniques proposed for economic and social studies have recently been shown to be a successful approach for characterizing information propagation in multi-hop wireless networks. We propose a set of efficient resource allocation algorithms and channel access scheduling protocols based on Latin squares and social centrality metrics for wireless mesh networks (WMNs) with multi-radio multi-channel (MRMC) communication capabilities, called , which can coexist with IEEE 802.11 DCF and be effectively applied in large scale WMNs. Based on interference information provided by the interference graph, uses nodal degree centrality to form cliques for intra-cluster communication, and betweenness centrality to choose bridge nodes to form cliques for inter-cluster communication in WMNs, and then applies Latin squares to map the clique-based clustering structure to radios and channels for wireless communication purposes. Afterwards, again applies Latin squares to schedule the channel access amongst nodes within each cluster in a collision-free manner. We evaluate using simulations, and results show that achieves much better performance than existing IEEE 802.11 standards and other multi-channel access control protocols. [Copyright &y& Elsevier]

Abstract: Security protocols operating over wireless channels can incur significant communication costs (e.g., energy, delay), especially under adversarial attacks unique to the wireless environment such as signal jamming, fake signal transmission, etc. Since wireless devices are resource constrained, it is important to optimize security protocols for wireless environments by taking into account their communication costs. Towards this goal, we first present a novel application of a signal-flow-based approach to analyze the communication costs of security protocols in the presence of adversaries. Our approach models a protocol run as a dynamic probabilistic system and then utilizes Linear System theory to evaluate the moment generating function of the end-to-end cost. Applying this technique to the problem of secret key exchange over a wireless channel, we quantify the efficiency of existing families of key exchange cryptographic protocols, showing, for example, that an ID-based approach can offer an almost 10-fold improvement in energy consumption when compared to a traditional PKI-based protocol. We then present a new key exchange protocol that combines traditional cryptographic methods with physical-layer techniques, including the use of “ephemeral” spreading codes, cooperative jamming, and role-switching. Utilizing signal flow analysis, we demonstrate that this new protocol offers performance advantages over traditional designs. [Copyright &y& Elsevier]

Abstract: Recent deployments of wireless sensor networks have targeted challenging monitoring and surveillance applications. The medium access control being the main source of energy wastage, energy-efficiency has always been kept in mind while designing the communication stack embedded in spread sensors. Especially, versatile protocols have emerged to offer a suitable solution over multiple deployment characteristics. In this study, we observe to what extent versatility applies to dynamic scenarios in which communications do not respect specific communication paradigms. We first provide a performance evaluation of two well-reputed versatile protocols (B-MAC (Polastre et al., 2004 ) and X-MAC (Buettner et al., 2006 )) under the conditions of such a scenario. The obtained results convinced us to propose more than versatility and pre-configured solutions, that is auto-adaptation. We then introduce the main contribution of this paper, an auto-adaptive algorithm that allows one to adjust the previously mentioned protocols while the network is operating. We analyze to what extent it outperforms the previously obtained results. [Copyright &y& Elsevier]

Abstract: In many wireless sensor network applications, nodes are mobile, while many protocols proposed for these networks assume a static network. Thus, it is important to evaluate if a traditional protocol designed for a static network can tolerate different levels of mobility. This paper provides an analytic model to investigate the effect of mobility on a well-known cluster-based protocol, LEACH. The model evaluates data loss after construction of the clusters due to node mobility, which can be used to estimate a proper update interval to balance the energy and data loss ratio. Thus, the results can help the network designer to adjust the topology update interval given a value of acceptable data loss threshold. A practical approach to increase the mobility tolerance of the protocol is applying a buffer zone to the transmission ranges of the nodes. The model is extended in order to consider the effect of buffer zone. To validate the analytic evaluations, extensive simulations are conducted and correctness of the evaluations is tightly verified. [Copyright &y& Elsevier]

Abstract: In the last few years, several different mesh network architectures have been conceived by both industry and academia; however, many issues on the deployment of efficient and fair transport protocols are still open. One of these issues is rate adaptation, that is, how to allocate the network resources among multiple flows, while minimizing the performance overhead. In order to address this problem, in this paper, we first define an analytical framework for a very simple topology. The model allows us to study the performance of an adaptive and responsive transport protocol when the effect of the lower layers are ignored. The mathematical approach alone does not represent a feasible solution, but it contributes to determining the strengths and weaknesses of our proposal. The main novelty of the proposed solution is that the congestion control approach is based on a hop-by-hop mechanism, which allows nodes to adapt their transmitting rates in a distributed way and to keep track of dynamic multi-hop network characteristics in a responsive manner. This is in contrast with classical literature solutions, founded on an end-to-end support. Anyway, to ensure the reliability, a coarse-grained end-to-end algorithm is integrated with the proposed hop-by-hop congestion control mechanism to provide packet level reliability at the transport layer. Performance evaluation, via extensive simulation experiments, shows that the proposed protocol achieves a high performance in terms of network throughput. [Copyright &y& Elsevier]

Abstract: In this paper, we propose an adaptive application-driven power management (AADPM) protocol for wireless information retrieval applications within the IEEE 802.11b infrastructure WLAN environment. Our goal is to minimize energy consumption while achieving low round trip time delay. We discuss the protocol and evaluate its effectiveness using the network simulator NS2. We also draw horizontal comparisons among a variety of PM methods reported in the literature. Experimental results show that, compared to the power save mode supported by 802.11b, AADPM reduces the network interface card energy consumption by 52% while only introducing 3% RTT delay. [Copyright &y& Elsevier]

In this paper we consider the potential for SCO link sharing in Bluetooth-based telephony base stations. A design referred to as the Bluetooth distributed voice access protocol (DVAP) is introduced. In DVAP, Bluetooth mobiles collect connectivity information which is provided to the base station infrastructure. Mobile node migration is then used to reduce blocking when a Bluetooth base station is carrying a full load of active SCO links. A simple heuristic referred to as dynamic base station selection is used for making the base station assignment. Simulation results are presented which show that DVAP has better voice call blocking performance than existing Bluetooth base station collaboration designs (in: IEEE Workshop on Wireless Local Networks, Tampa, Florida, November 2001). It is also shown that intelligent base station selection can support much higher levels of traffic loading at a given voice call blocking rate compared to an arbitrary base station assignment. [Copyright &y& Elsevier]

Recently, several fully distributed (localized) location-based routing protocols for a mobile ad hoc network were reported in literature. They are variations of directional (DIR), geographic distance (GEDIR) or progress-based (MFR) routing methods. In DIR methods, each node A (the source or intermediate node) transmits a message m to several neighbors whose direction is closest to the direction of D. In MFR (most forward progress within radius), and GEDIR (GEographic DIstance Routing) methods, when node A wants to send m to node D, it forwards m to its neighbor C whose projection or distance (respectively) is closest to D among all neighbors of A. The same procedure is repeated until D, if possible, is eventually reached. In this paper, we introduce three variants of multiple path c-GEDIR, c-DIR and c-MFR methods, in which m is initially sent to c best neighbors according to corresponding criterion, and afterwards, on intermediate nodes, it is forwarded to only the best neighbor. In the original c-path method, only the first received copy at intermediate nodes is forwarded to the best neighbor. In the alternate c-path method, the ith received copy is forwarded to ith best neighbor, according to the selected criterion. In the disjoint c-path method, each intermediate node, upon receiving the message, will forward it to its best neighbor among those who never received the message (thus, in effect, the methods attempts to create c disjoint paths). The simulation experiments with random graphs show that disjoint multiple path methods provide high success rates, and small hop counts for small values of c. They also have reduced flooding rates compared to the best existing multiple-path methods and/or methods that require memorizing past traffic, such as recently proposed LAR2, f-GEDIR, and DFS based routing, and can serve as a basis for scalable QoS routing in wireless networks. [Copyright &y& Elsevier]