17,446 research outputs found
Energy-Efficient NOMA Enabled Heterogeneous Cloud Radio Access Networks
Heterogeneous cloud radio access networks (H-CRANs) are envisioned to be
promising in the fifth generation (5G) wireless networks. H-CRANs enable users
to enjoy diverse services with high energy efficiency, high spectral
efficiency, and low-cost operation, which are achieved by using cloud computing
and virtualization techniques. However, H-CRANs face many technical challenges
due to massive user connectivity, increasingly severe spectrum scarcity and
energy-constrained devices. These challenges may significantly decrease the
quality of service of users if not properly tackled. Non-orthogonal multiple
access (NOMA) schemes exploit non-orthogonal resources to provide services for
multiple users and are receiving increasing attention for their potential of
improving spectral and energy efficiency in 5G networks. In this article a
framework for energy-efficient NOMA H-CRANs is presented. The enabling
technologies for NOMA H-CRANs are surveyed. Challenges to implement these
technologies and open issues are discussed. This article also presents the
performance evaluation on energy efficiency of H-CRANs with NOMA.Comment: This work has been accepted by IEEE Network. Pages 18, Figure
Toward End-to-End, Full-Stack 6G Terahertz Networks
Recent evolutions in semiconductors have brought the terahertz band in the
spotlight as an enabler for terabit-per-second communications in 6G networks.
Most of the research so far, however, has focused on understanding the physics
of terahertz devices, circuitry and propagation, and on studying physical layer
solutions. However, integrating this technology in complex mobile networks
requires a proper design of the full communication stack, to address link- and
system-level challenges related to network setup, management, coordination,
energy efficiency, and end-to-end connectivity. This paper provides an overview
of the issues that need to be overcome to introduce the terahertz spectrum in
mobile networks, from a MAC, network and transport layer perspective, with
considerations on the performance of end-to-end data flows on terahertz
connections.Comment: Published on IEEE Communications Magazine, THz Communications: A
Catalyst for the Wireless Future, 7 pages, 6 figure
Wearable Communications in 5G: Challenges and Enabling Technologies
As wearable devices become more ingrained in our daily lives, traditional
communication networks primarily designed for human being-oriented applications
are facing tremendous challenges. The upcoming 5G wireless system aims to
support unprecedented high capacity, low latency, and massive connectivity. In
this article, we evaluate key challenges in wearable communications. A
cloud/edge communication architecture that integrates the cloud radio access
network, software defined network, device to device communications, and
cloud/edge technologies is presented. Computation offloading enabled by this
multi-layer communications architecture can offload computation-excessive and
latency-stringent applications to nearby devices through device to device
communications or to nearby edge nodes through cellular or other wireless
technologies. Critical issues faced by wearable communications such as short
battery life, limited computing capability, and stringent latency can be
greatly alleviated by this cloud/edge architecture. Together with the presented
architecture, current transmission and networking technologies, including
non-orthogonal multiple access, mobile edge computing, and energy harvesting,
can greatly enhance the performance of wearable communication in terms of
spectral efficiency, energy efficiency, latency, and connectivity.Comment: This work has been accepted by IEEE Vehicular Technology Magazin
cISP: A Speed-of-Light Internet Service Provider
Low latency is a requirement for a variety of interactive network
applications. The Internet, however, is not optimized for latency. We thus
explore the design of cost-effective wide-area networks that move data over
paths very close to great-circle paths, at speeds very close to the speed of
light in vacuum. Our cISP design augments the Internet's fiber with free-space
wireless connectivity. cISP addresses the fundamental challenge of
simultaneously providing low latency and scalable bandwidth, while accounting
for numerous practical factors ranging from transmission tower availability to
packet queuing. We show that instantiations of cISP across the contiguous
United States and Europe would achieve mean latencies within 5% of that
achievable using great-circle paths at the speed of light, over medium and long
distances. Further, we estimate that the economic value from such networks
would substantially exceed their expense
- …