International audienceEnergy management in Wireless Sensor Networks (WSNs) is of paramount importance for the remotely deployed energy stringent sensor nodes. These nodes are typically powered by attached batteries. Several battery-driven energy conservation schemes are proposed to ensure energy efficient network operation. The constraints associated to the limited battery capacity shifted the research trend towards finding alternate sources by harvesting ambient energy. This survey presents a high level taxonomy of energy management in WSNs. We analyze different battery-driven energy consumption based schemes and energy harvesting based energy provisioning schemes. We also highlight the recent breakthrough of wireless energy transference to a sensor node as an alternative to typical batteries. We recommend taking into account recent energy provisioning advancements in parallel with the traditional energy conservation approaches for a sensor network while designing energy efficient schemes

This is the unspecified version of the paper.This version of the publication may differ from the final published version. by the large number of algorithms, techniques, and protocols that have been developed to save energy, and thereby extend the lifetime of the network. However, in the context of WSN's routing and dissemination, Connected Dominating Set (CDS) principle has emerged as the most popular method for energy-efficient topology control (TC) in WSN's. In a CDS-based topology control technique, a virtual backbone is formed which allows communication between any arbitrary pair of nodes in the network. In this paper, we present a CDS based topology control protocol -A1 -which forms an energy efficient virtual backbone. In our simulations, we compare the performance of A1 with three prominent CDS-based protocols namely Energy-efficient CDS (EECDS), CDS Rule K and A3. The results demonstrate that A1 performs consistently better in terms of message overhead and other selected metrics. Moreover, the A1 protocol not only achieves better connectivity under topology maintenance but also provides better sensing coverage when compared with the other protocols. Permanent repository link

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tem in realistic LoRaWAN network scenarios. The considered performance metrics are the achieved latency and throughput at the join server, which are measured as the number of concurrent clients and join request messages increase. The simulations results indicate that the system achieves efficient system performance up to an upper bound on the load level which involves 30 join requests from 1000 concurrent clients. However, the security and trust advantages that the blockchain technology offers, comes at the cost of performance deterioration for loads exceeding that level. This can be resolved by introducing additional join servers. A lightweight, cost effective blockchain based two factor authentication framework can also be employed in LoRaWAN networks when these are characterized by small number of networks servers and LoRa end devices. We demonstrate through simulations that this approach incurs additional delays and can be preferred for systems with no strict requirements of throughput and latency.

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Mobile users suffer from deteriorating signal quality due to vehicle penetration losses. To solve this, small cells are deployed within the vehicles to improve the Quality of Service (QoS). These small cells called moving small cell access points (MSAPs), however, suffer from backhaul issues since they would have to send a huge amount of data to the core network. To solve the backhaul problem, cloud radio access network (CRAN) along with the millimeter wave (mmwave) can be a viable solution for moving vehicles. However, in order to realize its potential benefits, an effective remote radio head (RRH) deployment strategy and the resource-efficient allocation are needed. In this paper, we investigate the placement of RRH alongside a railway track; then, for the placed RRH, a joint time slot and power allocation problem are formulated with an objective of maximizing the resource efficiency (RE) of the MSAP backhaul network. An optimal Branch and Bound Algorithm (BnBA) is proposed for the constituted non-linear integer problem, and the effects of changing various model parameters are investigated. The simulation results show that our proposed algorithm deviates 52% of the sub-optimal result.