1,256 research outputs found
Green Cellular Networks: A Survey, Some Research Issues and Challenges
Energy efficiency in cellular networks is a growing concern for cellular
operators to not only maintain profitability, but also to reduce the overall
environment effects. This emerging trend of achieving energy efficiency in
cellular networks is motivating the standardization authorities and network
operators to continuously explore future technologies in order to bring
improvements in the entire network infrastructure. In this article, we present
a brief survey of methods to improve the power efficiency of cellular networks,
explore some research issues and challenges and suggest some techniques to
enable an energy efficient or "green" cellular network. Since base stations
consume a maximum portion of the total energy used in a cellular system, we
will first provide a comprehensive survey on techniques to obtain energy
savings in base stations. Next, we discuss how heterogeneous network deployment
based on micro, pico and femto-cells can be used to achieve this goal. Since
cognitive radio and cooperative relaying are undisputed future technologies in
this regard, we propose a research vision to make these technologies more
energy efficient. Lastly, we explore some broader perspectives in realizing a
"green" cellular network technologyComment: 16 pages, 5 figures, 2 table
Energy-Delay Tradeoffs of Virtual Base Stations With a Computational-Resource-Aware Energy Consumption Model
The next generation (5G) cellular network faces the challenges of efficiency,
flexibility, and sustainability to support data traffic in the mobile Internet
era. To tackle these challenges, cloud-based cellular architectures have been
proposed where virtual base stations (VBSs) play a key role. VBSs bring further
energy savings but also demands a new energy consumption model as well as the
optimization of computational resources. This paper studies the energy-delay
tradeoffs of VBSs with delay tolerant traffic. We propose a
computational-resource-aware energy consumption model to capture the total
energy consumption of a VBS and reflect the dynamic allocation of computational
resources including the number of CPU cores and the CPU speed. Based on the
model, we analyze the energy-delay tradeoffs of a VBS considering BS sleeping
and state switching cost to minimize the weighted sum of power consumption and
average delay. We derive the explicit form of the optimal data transmission
rate and find the condition under which the energy optimal rate exists and is
unique. Opportunities to reduce the average delay and achieve energy savings
simultaneously are observed. We further propose an efficient algorithm to
jointly optimize the data rate and the number of CPU cores. Numerical results
validate our theoretical analyses and under a typical simulation setting we
find more than 60% energy savings can be achieved by VBSs compared with
conventional base stations under the EARTH model, which demonstrates the great
potential of VBSs in 5G cellular systems.Comment: 5 pages, 3 figures, accepted by ICCS'1
Effect of oil palm empty fruit bunches (OPEFB) fibers to the compressive strength and water absorption of concrete
Growing popularity based on environmentally-friendly, low cost and lightweight building materials in the construction industry has led to a need to examine how these characteristics can be achieved and at the same time giving the benefit to the environment and maintain the material requirements based on the standards required. Recycling of waste generated from industrial and agricultural activities as measures of building materials is not only a viable solution to the problem of pollution but also to produce an economic design of building
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