Wireless sensor networks (WSNs) have received considerable interest in recent years. These sensor nodes can gather information from the surrounding environment and transmit it to a designated location. Each sensor node in WSN typically has a battery with a limited capacity. Due to their large number and because of various environmental challenges, it is sometimes hard to replace this finite battery. As a result, energy-efficient communication is seen as a critical aspect in extending the lifespan of a sensor node. On the other hand, some applications that require large coverage and generate various sorts of data packets require multi-hop routing and quality of service (QoS) features. Therefore, in order to avoid network failure, these applications need an energy-efficient QoS MAC protocol that can support multiple levels of data packet priority and multi-hop routing features while focusing on energy conservation. An energy-aware QoS MAC protocol based on Prioritized Data and Multi-hop routing (EQPD-MAC) is proposed in this article. The EQPD-MAC protocol offers a simple yet effective cross-layer communication method. It provides timely delivery of multi-priority packets, uses an adaptive active time to limit idle listening, and integrates a robust routing protocol. Finally, the EQPD-MAC protocol’s performance was evaluated and compared to three other well-known QoS MAC protocols. The simulation findings show that the proposed protocol significantly decreases sensor node energy consumption by up to 30.3%, per-bit energy consumption by up to 29.6%, sink node energy consumption by up to 27.4% and increases throughput by up to 23.3%.

Energy efficiency plays a significant role for the network lifetime extension in wireless sensor networks (WSNs). On the other hand, higher priority information requires Quality of Service (QoS) to ensure their delivery with minimized delay. Furthermore, WSN nodes are low powered devices powered by a small battery where the capacity is limited. Therefore, there is a need to establish an energy-efficient Medium Access Control (MAC) protocol with minimum packet delays. In this paper, we propose an adaptive energy-efficient synchronous Quality of Service (QoS) MAC protocol, called Timeout Multi-priority based MAC (TMPQ-MAC) protocol. TMPQ-MAC proposed an adaptive energy-efficient MAC protocol which can dynamically extend and end the active time to handle the load variations in the network. The TMPQ-MAC also considers four different packet priorities so that data packets with urgent information get transmitted with minimum delay. Finally, the performance of the protocol is evaluated through simulations and provided a comparison with Multi-priority QoS MAC (MPQ-MAC), QoS Aware Energy-Efficient MAC (QAEE-MAC) and Energy Harvested Receiver Initiated MAC (ERI-MAC) protocols. The simulation results show that the TMPQ-MAC improves the energy consumption at the sender nodes and the average packet delays by up to 7.8% and 7.9%, respectively over other protocols.

Unmanned aerial vehicle (UAV) are getting considerable attention in various commercial applications including aerial package delivery system. This paper investigates the impact of UAV on the commercial cellular network that provides the required wireless connectivity to it. The paper proposes use of directional radiation pattern at both the BTS or Node-B of a CDMA cellular network and the UAV and presents performance evaluation of the proposed system and improvement over a conventional system comprising omnidirectional radiation. Significant amount of interference reduction and capacity enhancement over the conventional system are reported. Additionally, handoff (HO) performance of the proposed system is investigated, and it is shown that a reduction of the number of occurrence of HO from 50% to 75% can be achieved.