Wireless sensor networks have been developed in the way of higher speed, more stability, and more energy efficiency in recent years. Because most wireless sensors are powered by energy-constrained batteries, efficient energy consumption plays the most important role in the design of wireless sensor networks. For energy efficiency, aside from economizing the use of power in the sensor hardware, ...

To exploit multi-rate capability as well as improve performance in wireless local area networks (WLANs), many rate adaptation mechanisms are proposed on IEEE 802.11 media access control (MAC) layer. However, they lead to performance anomaly problem due to guarantee of throughput fairness. To solve this problem, many cooperative MAC protocols were proposed that are classified into packet aggrega...

due to the increasing interest on renewable sources in recent years, the studies on integration of distributed generation to the power grid have rapidly increased. in order to minimize line losses of power systems, it is crucially important to define the size and location of local generation to be placed. minimizing the losses in the system would bring two types of saving, in real life, one is ...

The delay tolerant networks (DTNs) is characterized by frequent disconnections and long delays of links among devices due to mobility, sparse deployment of devices, attacks, and noise, etc. Considerable research efforts have been devoted recently to DTNs enabling communications between network entities with intermittent connectivity. Unfortunately, mobile devices have limited energy capacity, a...

By introduction of relay nodes, LTE-Advanced can provide enhanced coverage and capacity at cell edges and hot-spot areas. The authors have been researching the issue of power saving in mobile communications technology such as WiMax and Long Term Evolution (LTE) for some years. Based on the previous idea of load-based power saving, two strategies each with associated schemes to integrated relay ...

While the 802.11 power saving mode (PSM) and its enhancements can reduce power consumption by putting the wireless network interface (WNI) into sleep as much as possible, they either require additional infrastructure support, or may degrade the transmission throughput and cause additional transmission delay. These schemes are not suitable for long and bulk data transmissions with strict QoS req...

One of the common underlying assumptions in IEEE 802.11 standards' ad hoc mode operations is that all stations in the same IBSS can hear each other directly. In other words, the ad hoc mode of 802.11 supports only single-hop ad hoc networks. When extended to multi-hop environments, IEEE 802.11 protocols show a poor performance, if they are able to work at all. This has been acknowledged by rese...

In traditional ad hoc networks, all nodes are considered equal and take equal part in the routing and forwarding of packets. We believe that this may not always be desirable. Rather, some nodes may be equipped with virtually unlimited power supplies, while others have to rely on battery power. Thus, we propose the creation of “infrastructured” ad hoc networks by the deployment of pseudo base-st...

This study shows the problem of power saving mechanism (PSM) that sleep intervals of uplink (UL) connections do not synchronize with sleep intervals of downlink (DL) connections. That is, the energy of a mobile station (MS) is not really saved if the DL connections are in the sleep mode while the UL connections are in normal mode, and vice versa. To avoid the asynchronism of power saving (PS) b...

Following recent advances in the performance of ad hoc networks, the limited life of batteries in mobile devices poses a bottleneck in their development. Consequently, how to minimize power consumption in the Medium Access Control (MAC) layer of ad hoc networks is an essential issue. The power-saving mode (PSM) of IEEE 802.11 involves the Timing Synchronization Function to reduce power consumpt...