Researchers have encountered many challenges in developing communication system in wireless body area networks (WBANs). These challenges include the dynamic characteristics of WBAN channels, limited energy resources, and strict requirements, such as high reliability and low latency. To achieve highly reliable and energy-efficient communication in the WBAN, temporal correlation model-based transmission power control (TCM-TPC) is proposed. In this method, the channel condition is firstly determined based on a long-term mean channel gain and the last known channel gain using a temporal correlation model. The channel is estimated as a conditional distribution of channel gains. After that, the transmit output power is selected from the estimated channel to satisfy a pre-defined outage probability. Performance of the proposed TCM-TPC method was evaluated on a network simulator for a walking scenario. The evaluation results showed that the TCM-TPC had up to 1.48% of packet loss, while other TPC methods had up to 6.86% of packet loss. Furthermore, for a high data rate application, the TCM-TPC showed the lowest energy consumption for all sensor nodes.

One of the lifetime maximisation methods for wireless sensor network (WSN) depends on organising the dense sensors into groups which can work in a cooperative sequential manner. Each group contains a subset of sensors that cover all the monitored area and is called a complete cover or simply a cover. Increasing the number of organised covers and maximising the covers lifetime enable longer network lifetime. Here, the authors investigate the WSN lifetime problem as a two-objective optimisation problem. The first objective is to find the maximum number of covers. The second objective considers the problem of wasted energy. Minimising the wasted energy in the critical sensors is achieved by defining a difference factor (DF). The DF is an indication of the difference between the critical sensor lifetime and the cover lifetime. This second objective is compared with other choices in the literature such as minimising the overlapping and minimising the variance. This optimisation problem is addressed using non-dominated sorting genetic algorithm-II (NSGA-II). Simulation results are conducted for the network lifetime when using one-objective and different two-objective optimisation problem. The choice of DF as the second objective is proved to overcome drawbacks of other second objectives choices.

Both the backoff time and idle listening are the key issues affecting the performance of wireless sensor networks. Therefore, the energy-efficient and traffic-adaptive Z-medium access control protocol is proposed in this study. Firstly, it avoids idle listening by setting a fixed contention window in single round to effectively improve the fairness in the backoff strategy. At the same time, it ensures the nodes with less residual energy have priority to access channel and realise the load balance. Secondly, the protocol uses the improved explicit contention notification (ECN) mechanism to reduce the energy consumption caused by sending the ECN messages repeatedly in a period of time and prolong the network lifetime. Lastly, the channel flags are introduced at the top of data frames to make an appointment on the channel so as to avoid the idle listening. Simulation results show that, when, compared with other similar algorithms, the collision rate is reduced by at least 14.2%, the time when the first node dies is prolonged by at least 135 rounds, and the average network energy consumption is reduced by at least 23%.

Future wireless communication systems will consist of multiple networks with various capabilities. Wireless networks may encounter severe distortions due to the presence of interfering signals generated at some power stations dedicated to smart grid applications. In fact, severe environmental effects of high voltage substations must be considered, particularly impulsive noise needs to be taken into account. Firstly, to cope with this kind of hostile environment, an efficient channel coding scheme in a mono-user system is proposed, when one source user transmits data directly to one terminal user. Performance analysis shows that the proposed coding schemes based on rank metric codes are very efficient to eliminate impulsive noise in mono-user mode. Furthermore, this approach are expanded in order to show the efficiency of rank codes in Wireless Sensors Networks (WSNs), when considering the problem of collecting data in WSNs in the presence of impulsive noise errors together with AWGN channel. To increase the reliability of the system, an advanced Network Coding technique (NC) is applied based on LRPC (Low Rank Parity Check) codes which exhibits noteworthy performances.

Wireless sensor networks (WSNs) have a wide range of applications in various fields. One of the most recent emerging applications are in the world of Internet of Things (IoT), which allows inter-connection of different objects or devices through the Internet. However, limited battery power is the major concern of WSNs as compared to mobile ad-hoc network, which affects the longevity of the network. Hence, a lot of research has been focused on to minimise the energy consumption of the WSNs. Designing of a hierarchical clustering algorithm is one of the numerous approaches to minimise the energy of the WSNs. In this study, the existing low-energy adaptive clustering hierarchy (LEACH) clustering protocol is modified by introducing a threshold limit for cluster head selection with simultaneously switching the power level between the nodes. The proposed modified LEACH protocol outperforms as compared to the existing LEACH protocol with 67% rise in throughput and extending the number of alive nodes to 1750 rounds which can be used to enhance the WSN lifetime. When compared with other energy efficient protocols, it is found that the proposed algorithm performs better in terms of stability period and network lifetime in different scenarios of area, energy and node density.

Reducing energy consumption is a key challenge in the design of any routing protocol dedicated to wireless sensor networks (WSNs). In this study, the authors introduce a new low energy consumption protocol based on a cooperative relaying technique. The proposed protocol is called distributed cooperative relaying low energy adaptive clustering hierarchy (DCR-LEACH) protocol, and is a way of improving the LEACH protocol. The authors have exploited cooperative relaying transmission techniques, in order to enhance LEACH for large-scale WSNs, whereby, a cluster head cooperates with the most energetic nodes in order to transmit collected data to the sink. To evaluate the energy efficiency of the proposed DCR-LEACH, they derive the expressions of energy consumption by applying a cooperative relaying technique and simulate the DCR-LEACH using NS-2 for three different scenarios. To confirm the efficiency of the DCR-LEACH protocol, they compare the proposed scheme with both LEACH and multi-hop routing LEACH (MR-LEACH) protocols. The experimental results prove that for large-scale WSNs, the performance of DCR-LEACH protocol is better than MR-LEACH and conventional LEACH in terms of network lifetime, energy consumption, and number of data transmission.

Low-power wide area networks (LPWANs) are gaining momentum within Internet of Things circles, thanks to their inherent capabilities to simplify network topologies and increase coverage in low-rate and low-power communications. This study focuses on a specific LPWAN technology, namely Long Range Wireless Area Network (LoRaWAN), which is being widely investigated by the research community worldwide. LoRaWAN offers many noticeable features, including wide coverage areas, security by design, power consumption and bandwidth optimisation, and a high degree of flexibility and reconfigurability. Unfortunately, in spite of these valuable characteristics, LoRaWAN appliances are often closed source and proprietary. To bridge the gap, this study proposes a prototype, which has been designed and set up using open low-cost experimental boards and programming tools, only. Moreover, an experimental campaign has been carried out in order to demonstrate the effectiveness of the developed platform.