Adaptive Energy Efficient MAC Research Articles

An Adaptive Energy Efficient MAC Protocol for RF Energy Harvesting WBANs

Continuous and remote health monitoring medical applications with heterogeneous requirements can be realized through wireless body area networks (WBANs). Energy harvesting is adopted to enable low-power health applications and long-term monitoring without battery replacement, which have drawn significant interest recently. Because energy harvesting WBANs are obviously different from battery-powered ones, network protocols should be designed accordingly to improve network performance. In this article, an efficient cross-layer media access control protocol is proposed for radio frequency powered energy harvesting WBANs. We redesigned the superframe structure, which can be rescheduled by the coordinator dynamically. A time switching (TS) strategy is used when sensors harvest energy from radio frequency signals broadcast by the coordinator, and a transmission power adjustment scheme is proposed for sensors based on the energy harvesting efficiency and the network environment. Energy efficiency can be effectively improved that more packets can be uploaded using limited energy. The length of the energy harvesting period is determined by the coordinator to balance the channel resources and energy requirements of sensors and further improve the network performance. Numerical simulation results show that our protocol can provide superior system performance for long-term periodic health monitoring applications.

An Energy Efficient Adaptive Wake-Up Radio MAC (EEAWuR-MAC) Protocol for IoT Wireless Body Area Networks

In this paper an improved adaptive energy efficient MAC (EEAWuR-MAC) protocol is proposed to handle emergency data transmission in internet of things wireless body area networks (WBANs) by incorporating the wake-up radio (WuR) mechanism. In WuR based WBANs a body node starts data transmission in an on-demand manner by sending a WuR-message (WuM). The WuR based MAC (WuR-MAC) protocols reduces the latency of data transmission and saves more energy in contrast to duty-cycling MAC protocols. Therefore, the superiority of WuR mechanism over duty-cycling shifts the trend towards WuR-MAC protocols. Furthermore, the investigation of emergency data (ED) handling mechanisms is still required at MAC layer. It is observed that inappropriately configuring the 802.15.4 MAC parameters may lead to performance deterioration in terms of energy efficiency and quality of service (QoS) such as throughput and delay. Therefore, a substantial modification in the existing IEEE 802.15.4 super-frame structure is essentially required for efficiently handling the ED transmission. The proposed protocol employs a modified superframe structure of IEEE 802.15.4 MAC, mainly designed for ultra-low power medical applications under normal and emergency traffic conditions concurrently without any interruption. A systematic analytical framework is developed to derive the mathematical expressions based on M/G/1/2 queuing model to evaluate the performance of proposed protocol in terms of throughput, delay and energy consumption and its validation is carried out using MATLAB simulation.

BSC-MAC: Energy efficiency in wireless sensor networks with base station control

Wireless sensor networks (WSNs) are now used in many areas and the interest in this technology continues to increase. Due to the small structure of the processor, the memory of the sensor nodes forming the wireless sensor networks, and as they are operated by a battery, the most important problem appears to be the energy issue. The battery depletion of the sensor nodes randomly deployed in critical areas may negatively interfere with part or all of the network communication and may cause the life of the entire network to terminate. Therefore, many studies have been conducted in the field of energy efficiency. In this study, Base Station Controlled MAC (BSC-MAC), which is a new design of MAC, is recommended. The BSC-MAC protocol presents an adaptive approach for energy efficiency. It determines the nodes on the network as root and source nodes and manages a sleep schedule according to these structures. The simulation of the BSC-MAC protocol was performed with ns-2 and compared to similar protocols, such as adaptive energy efficient MAC (AEEMAC), pattern MAC (P-MAC), and sensor MAC (S-MAC).