Enhanced Power Savings Research Articles

NR DCP: An Enhanced Power Saving Mechanism With Wake-Up Signal Enabled DRX

NR DCP: An Enhanced Power Saving Mechanism With Wake-Up Signal Enabled DRX

Small-World and Scale-Free Network Models for IoT Systems

It is expected that Internet of Things (IoT) revolution will enable new solutions and business for consumers and entrepreneurs by connecting billions of physical world devices with varying capabilities. However, for successful realization of IoT, challenges such as heterogeneous connectivity, ubiquitous coverage, reduced network and device complexity, enhanced power savings, and enhanced resource management have to be solved. All these challenges are heavily impacted by the IoT network topology supported by massive number of connected devices. Small-world networks and scale-free networks are important complex network models with massive number of nodes and have been actively used to study the network topology of brain networks, social networks, and wireless networks. These models, also, have been applied to IoT networks to enhance synchronization, error tolerance, and more. However, due to interdisciplinary nature of the network science, with heavy emphasis on graph theory, it is not easy to study the various tools provided by complex network models. Therefore, in this paper, we attempt to introduce basic concepts of graph theory, including small-world networks and scale-free networks, and provide system models that can be easily implemented to be used as a powerful tool in solving various research problems related to IoT.

A finite element based data analytics approach for modeling turning process of Inconel 718 alloys

Turning is a primary metal cutting process deployed extensively for producing components to required shape and dimensions. A commonly used material is Inconel 718, which exhibits an inferior economic feasibility in terms of turning due to its poor machinability characteristics. A combined finite element based data analytics model is introduced in this work. Finite element modeling was used to predict the cutting force while Genetic Programming was used to obtain the mathematical relation between the process variables and the cutting force. The weighted parameter analysis was conducted on the mathematical model which revealed that depth of cut and cutting angle exerts significant influence on the cutting force. As turning process is generally specified by a given depth of cut which dictates the material removal rate, optimization of tool cutting angle can result in enhanced power savings. It is anticipated that the findings obtained from this study can result in greater power savings in turning process of hard-to-machine materials which can lead to a sustainable manufacturing process.

Radio Interface Evolution Towards 5G and Enhanced Local Area Communications

The exponential growth of mobile data in macronetworks has driven the evolution of communications systems toward spectrally efficient, energy efficient, and fast local area communications. It is a well-known fact that the best way to increase capacity in a unit area is to introduce smaller cells. Local area communications are currently mainly driven by the IEEE 802.11 WLAN family being cheap and energy efficient with a low number of users per access point. For the future high user density scenarios, following the 802.11 HEW study group, the 802.11ax project has been initiated to improve the WLAN system performance. The 3GPP LTE-advanced (LTE-A) also includes new methods for pico and femto cell's interference management functionalities for small cell communications. The main problem with LTE-A is, however, that the physical layer numerology is still optimized for macrocells and not for local area communications. Furthermore, the overall complexity and the overheads of the control plane and reference symbols are too large for spectrally and energy efficient local area communications. In this paper, we provide first an overview of WLAN 802.11ac and LTE/LTE-A, discuss the pros and cons of both technology areas, and then derive a new flexible TDD-based radio interface parametrization for 5G local area communications combining the best practices of both WiFi and LTE-A technologies. We justify the system design based on local area propagation characteristics and expected traffic distributions and derive targets for future local area concepts. We concentrate on initial physical layer design and discuss how it maps to higher layer improvements. This paper shows that the new design can significantly reduce the latency of the system, and offer increased sleeping opportunities on both base station and user equipment sides leading to enhanced power savings. In addition, through careful design of the control overhead, we are able to improve the channel utilization when compared with LTE-A.

Enhanced Power Saving Mechanism for Type I and Type II Power Saving Classes in IEEE 802.16e

A mobile station (MS) in an IEEE 802.16e network manages its limited energy using the sleep mode operation. An MS can power down its physical operation components during the unavailability interval of the sleep mode. To reduce energy consumption by increasing the unavailability interval, this paper proposes an enhanced power saving mechanism (ePSM) when both activated Type I and Type II power saving classes (PSCs) exist in an MS. A performance evaluation confirms that ePSM results in the improved performance in terms of the unavailability interval as well as the energy consumption than conventional schemes.

Dual Supply Voltages and Dual Clock Frequencies for Lower Clock Power and Suppressed Temperature-Gradient-Induced Clock Skew

Two new clocking methodologies based on supply voltage and frequency scaling are proposed in this paper for lowering the power consumption and the temperature-fluctuation-induced skew without degrading the clock frequency. The clock signal is distributed globally at a scaled supply voltage with a single clock frequency with the first clocking methodology. Alternatively, dual supply voltages and dual signal frequencies are employed with the second methodology that provides enhanced power savings. The optimum supply voltage that minimizes clock skew is 44% lower than the nominal supply voltage in a 0.18 ¿m TSMC CMOS technology. Novel multi-threshold voltage level converters and frequency multipliers are employed at the leaves of the clock trees in order to maintain the synchronous system performance. The temperature-fluctuation-induced skew and the power consumption are reduced by up to 80% and 76%, respectively, with the proposed dual supply voltage and dual frequency clock distribution networks as compared to a standard clock tree operating at the nominal supply voltage with a single clock frequency.