Search results for "energiatehokkuus"
showing 10 items of 34 documents
Energy Efficient Resource Allocation for Wireless Powered UAV Wireless Communication System with Short Packet
2023
The unmanned aerial vehicle (UAV), which is prominent in its flexibility and low cost, is considered to be fully utilized in the future wireless communication system to provide flexible services and improve connectivities. In this paper, we investigate the resource allocation problem in a wireless powered UAV communication system. In this considered system, The UAV acts as hybrid access point (HAP), which can first perform wireless power transfer in the downlink and charge the Internet of Thing (IoT) user devices (UDs). The UDs can use the harvested energy to deliver the data to the UAV. In the uplink, we explicitly consider short packet communication (SPC) as the transmission feature, whic…
Energy Efficiency Optimization for Multi-cell Massive MIMO : Centralized and Distributed Power Allocation Algorithms
2021
This paper investigates the energy efficiency (EE) optimization in downlink multi-cell massive multiple-input multiple-output (MIMO). In our research, the statistical channel state information (CSI) is exploited to reduce the signaling overhead. To maximize the minimum EE among the neighbouring cells, we design the transmit covariance matrices for each base station (BS). Specifically, optimization schemes for this max-min EE problem are developed, in the centralized and distributed ways, respectively. To obtain the transmit covariance matrices, we first find out the closed-form optimal transmit eigenmatrices for the BS in each cell, and convert the original transmit covariance matrices desi…
Energy-Efficient Edge Computing Service Provisioning for Vehicular Networks: A Consensus ADMM Approach
2019
In vehicular networks, in-vehicle user equipment (UE) with limited battery capacity can achieve opportunistic energy saving by offloading energy-hungry workloads to vehicular edge computing nodes via vehicle-to-infrastructure links. However, how to determine the optimal portion of workload to be offloaded based on the dynamic states of energy consumption and latency in local computing, data transmission, workload execution and handover, is still an open issue. In this paper, we study the energy-efficient workload offloading problem and propose a low-complexity distributed solution based on consensus alternating direction method of multipliers. By incorporating a set of local variables for e…
Energy efficient and distributed resource allocation for wireless powered OFDMA multi-cell networks
2017
In this paper, we investigate the energy efficient resource allocation problem for the wireless powered OFDMA multi-cell networks. In the considered system, the users who have data to transmit in the uplink can only be empowered by the wireless power obtained from multiple base stations (BSs) with a large scale of multiple antennas in the downlink. A time division protocol is considered to divide the time of wireless power transfer (WPT) in the downlink and wireless information transfer (WIT) in the uplink into separate time slot. With the objective to improve the energy efficiency (EE) of the system, we propose the antenna selection, time allocation, subcarrier and power allocation schemes…
Energy efficient optimisation for large-scale multiple-antenna system with WPT
2018
In this study, an energy-efficient optimisation scheme for a large-scale multiple-antenna system with wireless power transfer (WPT) is presented. In the considered system, the user is charged by a base station with a large number of antennas via downlink WPT and then utilises the received power to carry out uplink data transmission. Novel antenna selection, time allocation and power allocation schemes are presented to optimise the energy efficiency of the overall system. In addition, the authors also consider channel state information cannot be perfectly obtained when designing the resource allocation schemes. The non-linear fractional programming-based algorithm is utilised to address the …
Energy efficiency in wireless networks
2013
Tämä pro gradu -työ on sekundääritutkimuksena tehty kirjallisuuskatsaus energiatehokkuuden tarkastelusta langattomissa verkoissa. Työssä tarkastellaan erilaisia mobiiliverkkojen energiansäästömahdollisuuksia. Pääpaino työssä on suunnattu erityisesti 3G ja LTE -verkkoihin, kuitenkin eksoottisempiakaan verkkoja unohtamatta. Työ alkaa erilaisten mobiiliverkkojen energiansäästösyiden ja tutkimusmotivaattoreiden tunnistamisella ja jatkuu langattomien verkkojen energian kulutuksen jaotuksella, sekä erilaisten energiansäästömahdollisuuksien vertailuilla. Työn empiirisessä osassa nostetaan lisäksi esille lyhyt Octave-simulaatio kollaboroivan mobiilipilven noodien energiansa…
Employee commitment to energy management : a qualitative interview study about employee commitment to energy management in industrial companies and p…
2015
Energy management is increasingly important to organisations that consume significant amounts of energy mainly due to the needs to comply with changing legislation and for saving financial resources. Even though energy management has received academic attention, it has not been studied in the perspective of employee commitment. Employee commitment may create various benefits to an organisation and its employees. Hence, this study aims at creating a better understanding of why employees commit to energy management and how it may be enhanced. This qualitative study was conducted using theme interviews as a data collection method. 14 employees, working among energy management, in eleven organi…
Efficient Power Allocation for Multi-Cell Uplink NOMA Network
2019
Digital technologies are rapidly shaping the modern concepts of urbanization. It is a key element of developing practical smart cities of the future. In fact, they are the catalyst for the increasing networking of all areas of life in a smart city. Recent development in the domain of communication technologies has opened new avenues to realize the concept of smart cities. One of such communication technology is non-orthogonal multiple access (NOMA) for future cellular communications. This article, therefore, focuses on the interference management of uplink cellular NOMA systems. Specifically, we propose a power optimization technique for NOMA to improve the sum-rate in a multi-cell environm…
Collaborative Mobile Clouds: An Energy Efficient Paradigm for Content Sharing
2018
On the way toward enabling efficient content distribution, reducing energy consumption and prolonging battery life of mobile equipment, an emerging paradigm, i.e., mobile cloud, which is based on content distribution, was proposed. As a mobile platform that is oriented toward content distribution, mobile cloud is also foreseen as an energy-efficient solution for future wireless networks. The benefits of using CMC for content distribution or distributed computing from social networking perspectives have been studied earlier. In this article, we first present the concepts of CMC and then discuss the energy-efficiency benefits from the system-level point-of-view as well as open challenges in d…