Abstract For many wireless sensor networks applications, a powerful localization algorithm is required to determine the exact positions of sensor nodes. In this paper, a new localization algorithm is presented which combines the distance vector hop (DV-Hop) algorithm with the shuffled shepherd optimization algorithm to determine the position for each unknown node within 3-D space. Studying the localization problem in 3-D space is more realistic, but more challenging due to the enlarged search space. Comparison of our proposed algorithm with its alternatives in literature shows that it offers improved accuracy and more stable performance with respect to changes in nodes density and communication range.

Abstract Device‐to‐device (D2D) communications play a significant role in increasing the capacity of cellular networks. D2D enables direct interaction between mobile users without traversing the base station (BS) and at the same time causes interference between D2D and cellular links which can affect the system performance. To ensure efficient and reliable D2D operations within a cellular network, the related quality of service (QoS) requirement needs to be met in the design of such a system involving both D2D and cellular users in a same network. In this study, we have investigated three different transmission schemes (cellular, D2D and cooperative D2D modes) by deriving the closed‐form expressions of key QoS performance such as system reliability, achievable data rate, and energy efficiency for these three transmission schemes. Based on this establishment, we have also examined the effects of using different numbers of parallel relay branches and different number of relays within each branch on the network performance to reveal how effectively the cooperative D2D can enhance QoS in comparison with other transmission methods. The proposed approach can be optimised through adaptively selecting appropriate transmission schemes and, as a result, good trade‐offs between system reliability and efficiency can also be achieved under various environmental conditions.

With a fast growth in world population, the citizens expect a highly sophisticated lifestyle with the help of new technologies. The heavy traffic and congestion on the road in the crowded urban cities have been occurred due to the increase of the population in these cities accordingly, the number of vehicles. As a result, the importance of traffic lights which give safety to the users on roads and reduce the traffic jam that causes great loose in both time and energy as fuel. This paper focuses on the identification of the conditions for establishing the optimum appropriate distance between two successive traffic lights in order to decrease the traffic jamming with optimizing the dynamic traffic light time that needed to reduce the jam. The proposed approach is based on the development of analytical model for the suggested idea and the assessment of its performance.