Abstract Support of Voice over Internet Protocol (VoIP) services in wireless mesh networks requires implementation of efficient policies to support low‐delay data delivery. Multipath routing is typically supported in wireless mesh networks at the network level to provide high fault tolerance and load balancing because links in the proximity of the wireless mesh gateways can be very stressed and overloaded, thus causing scarce performance. As a consequence of using multipath solutions, lower delay and higher throughput can be supported also when a given path is broken because of mobility or bad channel conditions, and alternative routes are available. This can be a relevant improvement especially when assuming that real‐time traffic, such as VoIP, travels into the network. In this paper, we address the problem of Quality of Service (QoS) support in wireless mesh networks and propose a multipath routing strategy that exploits the Mean Opinion Score (MOS) metric to select the most suitable paths for supporting VoIP applications and performing adaptive load balancing among the available paths to equalize network traffic. Performance results assess the effectiveness of the proposed approach when compared with other existing methodologies. Copyright © 2015 John Wiley & Sons, Ltd.

The number of smart things is growing exponentially. By 2020, tens of billions of things will be deployed worldwide, collecting a wealth of diverse data. Traditional computing models collect in-field data and then transmit it to a central data center where analytics are applied to it, but this is no longer a sustainable model. New approaches and new technologies are required to transform enormous amounts of collected data into meaningful information. Technology also will enable the interconnection around things in the IoT ecosystem but further research is required in the development, convergence and interoperability of the different IoT elements. In this paper, we provide a picture of the main technological components needed to enable the interconnection among things in order to realize IoT concepts and applications.

This paper deals with a novel forwarding scheme for wireless sensor networks aimed at combining low computational complexity and high performance in terms of energy efficiency and reliability. The proposed approach relies on a packet-splitting algorithm based on the Chinese Remainder Theorem (CRT) and is characterized by a simple modular division between integers. An analytical model for estimating the energy efficiency of the scheme is presented, and several practical issues such as the effect of unreliable channels, topology changes, and MAC overhead are discussed. The results obtained show that the proposed algorithm outperforms traditional approaches in terms of power saving, simplicity, and fair distribution of energy consumption among all nodes in the network.

The network-centric warfare concept pursues information superiority as the key strategic advantage. However, information can have a different strategic value depending on its criticality and, thus, communication systems should provide higher priority to critical data. In this paper, performance of different approaches to achieve such differentiation in TDMA satellite-based tactical communication systems are provided. More specifically, we will evaluate the impact of the correlation between the criticality level of information sources that are in proximity to each other. To this purpose, a Markovian model of the process modeling the criticality level dynamics of information sources belonging to the same group is defined and implemented in the ns-2 simulation environment. Simulation results demonstrate that the correlation between the criticality level of information sources in proximity to each other significantly impact the performance of the communication system.

In this paper we propose a routing approach aimed at enhancing the quality of Voice-over-IP (VoIP) transmissions in multipath Wireless Mesh Networks. The proposed approach executes a path switching based on the estimation of the Mean Opinion Score (MOS) for each available path of the mesh network. Performance results conducted through simulations show that the proposed approach, when compared to a random choice of the available paths, is highly effective in improving the performance of the VoIP calls in both static and dynamic scenarios.

One of the most important applications of wireless sensor networks (WSNs) undoubtedly is the emergency management. In particular, sensor nodes can be helpful for both preventing and recovering emergency situations. During critical emergency situations, having a WSN easy to access and manage is a mandatory requirement. So far, sensor networks have been based on custom protocols that make difficult to access and configure sensors by users that are different from the original designers. Today, with the advent of IPv6, integration between a sensor network and Internet becomes feasible. In this paper, we discuss the IPv6 capabilities that can be effectively exploited jointly with 6LoWPAN, and we illustrate a testbed based on an implementation of IPv6 over IEEE 802.15.4. We demonstrate that, by using an open source module we have purposely developed to run over 6LoWPAN, a user equipped with some few common network utilities can remotely access the WSN and change run-time the state and configuration of every single sensor node.

The main aim of this paper is to generalize and improve a recently proposed forwarding technique based on the Chinese Remainder Theorem (CRT). The proposed technique outperforms more traditional approaches in terms of both energy efficiency and fair distribution of energy consumption, and requires very few changes to the commonly used forwarding schemes for its implementation. In particular, in this paper it is shown how to apply the CRT-based forwarding method on a realistic wireless network where unreliable erasure channels are considered together with topological changes. Furthermore, an analytical model for the novel forwarding technique has been derived and the trade-off between reliability and energy saving has been investigated.

In this paper we discuss the use of the Chinese Remainder Theorem (CRT) for a novel forwarding scheme in wireless sensor networks. The proposed approach is characterized by a computationally simple packet splitting procedure able to reduce the energy needed for transmission and increase the network lifetime accordingly. Simulation results show that the proposed algorithm outperforms more traditional approaches in terms of both energy efficiency and fair distribution of energy consumption among all nodes in the network.

In a delay-tolerant sensor network where the sink is mobile, a node can conveniently hold an information packet until the sink comes closer. This allows to both decrease the number of wireless hops required to deliver the information to the sink and reduce energy consumption. Thus, mobility of nodes can be exploited to increase energy efficiency in sensor networks. However, a major drawback of the above policy is that it causes delay which may be not acceptable for the application. In this paper a trade-off between energy efficiency and delay is investigated. More specifically, an analytical framework which allows to evaluate the expected delivery cost with respect to the maximum delay acceptable for the application is derived and assessed by comparison with simulation results. Numerical results show that the analytical framework is very accurate and, as expected, accuracy increases as the density of nodes in the network increases.

Sensor networks are characterized by limited battery supplies. Due to this feature, communication protocols specifically designed for these networks should be aimed at minimizing energy consumption. To this purpose, the sensor's capability of transmitting with different power levels can be exploited. With this in mind, in this paper an integrated MAC/routing protocol, called MACRO, which exploits the capability of sensor devices to tune their transmission power is introduced. The proposed protocol requires that each node only knows its own coordinates and the coordinates of the destination, but does not require any exchange of location information. In order to select the next relay node, a competition is triggered at each hop, so that the most energy efficient relay node is chosen. This is achieved through maximization of a newly introduced parameter, called weighted progress factor, which represents the progress towards the destination per unit of transmitted power. To this aim, an analytical framework which guarantees that MACRO performs the best choice is derived. MACRO performance is evaluated through ns-2 simulation and compared to other relevant routing schemes. Performance results show that the proposed protocol outperforms other solutions in terms of energy efficiency and boosts data aggregation.

It is well known that TCP is unfair when connections with different round trip times share the same bottleneck. In the literature TCP fairness in wired networks has been widely studied but little effort has been devoted to this issue in wireless networks where new problems arise. Objective of this paper is investigating on the possibility of achieving TCP fairness through power management in wireless CDMA networks. The basic idea is to allow long round trip time connections, which are usually the most disadvantaged, to have higher signal-to-interference ratio levels. An analytical framework is introduced to calculate, for each mobile terminal, the appropriate transmission power giving fairness. The impact of such power management scheme on fairness and overall throughput performance is evaluated by means of both analysis and simulation.