1,980 research outputs found
Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks
Soaring capacity and coverage demands dictate that future cellular networks
need to soon migrate towards ultra-dense networks. However, network
densification comes with a host of challenges that include compromised energy
efficiency, complex interference management, cumbersome mobility management,
burdensome signaling overheads and higher backhaul costs. Interestingly, most
of the problems, that beleaguer network densification, stem from legacy
networks' one common feature i.e., tight coupling between the control and data
planes regardless of their degree of heterogeneity and cell density.
Consequently, in wake of 5G, control and data planes separation architecture
(SARC) has recently been conceived as a promising paradigm that has potential
to address most of aforementioned challenges. In this article, we review
various proposals that have been presented in literature so far to enable SARC.
More specifically, we analyze how and to what degree various SARC proposals
address the four main challenges in network densification namely: energy
efficiency, system level capacity maximization, interference management and
mobility management. We then focus on two salient features of future cellular
networks that have not yet been adapted in legacy networks at wide scale and
thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and
device-to-device (D2D) communications. After providing necessary background on
CoMP and D2D, we analyze how SARC can particularly act as a major enabler for
CoMP and D2D in context of 5G. This article thus serves as both a tutorial as
well as an up to date survey on SARC, CoMP and D2D. Most importantly, the
article provides an extensive outlook of challenges and opportunities that lie
at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201
Cooperative Energy Trading in CoMP Systems Powered by Smart Grids
This paper studies the energy management in the coordinated multi-point
(CoMP) systems powered by smart grids, where each base station (BS) with local
renewable energy generation is allowed to implement the two-way energy trading
with the grid. Due to the uneven renewable energy supply and communication
energy demand over distributed BSs as well as the difference in the prices for
their buying/selling energy from/to the gird, it is beneficial for the
cooperative BSs to jointly manage their energy trading with the grid and energy
consumption in CoMP based communication for reducing the total energy cost.
Specifically, we consider the downlink transmission in one CoMP cluster by
jointly optimizing the BSs' purchased/sold energy units from/to the grid and
their cooperative transmit precoding, so as to minimize the total energy cost
subject to the given quality of service (QoS) constraints for the users. First,
we obtain the optimal solution to this problem by developing an algorithm based
on techniques from convex optimization and the uplink-downlink duality. Next,
we propose a sub-optimal solution of lower complexity than the optimal
solution, where zero-forcing (ZF) based precoding is implemented at the BSs.
Finally, through extensive simulations, we show the performance gain achieved
by our proposed joint energy trading and communication cooperation schemes in
terms of energy cost reduction, as compared to conventional schemes that
separately design communication cooperation and energy trading
A New Look at Physical Layer Security, Caching, and Wireless Energy Harvesting for Heterogeneous Ultra-dense Networks
Heterogeneous ultra-dense networks enable ultra-high data rates and ultra-low
latency through the use of dense sub-6 GHz and millimeter wave (mmWave) small
cells with different antenna configurations. Existing work has widely studied
spectral and energy efficiency in such networks and shown that high spectral
and energy efficiency can be achieved. This article investigates the benefits
of heterogeneous ultra-dense network architecture from the perspectives of
three promising technologies, i.e., physical layer security, caching, and
wireless energy harvesting, and provides enthusiastic outlook towards
application of these technologies in heterogeneous ultra-dense networks. Based
on the rationale of each technology, opportunities and challenges are
identified to advance the research in this emerging network.Comment: Accepted to appear in IEEE Communications Magazin
Cost-Aware Green Cellular Networks with Energy and Communication Cooperation
Energy cost of cellular networks is ever-increasing to match the surge of
wireless data traffic, and the saving of this cost is important to reduce the
operational expenditure (OPEX) of wireless operators in future. The recent
advancements of renewable energy integration and two-way energy flow in smart
grid provide potential new solutions to save the cost. However, they also
impose challenges, especially on how to use the stochastically and spatially
distributed renewable energy harvested at cellular base stations (BSs) to
reliably supply time- and space-varying wireless traffic over cellular
networks. To overcome these challenges, in this article we present three
approaches, namely, {\emph{energy cooperation, communication cooperation, and
joint energy and communication cooperation}}, in which different BSs
bidirectionally trade or share energy via the aggregator in smart grid, and/or
share wireless resources and shift loads with each other to reduce the total
energy cost.Comment: Submitted for possible publicatio
Minimum Throughput Maximization for Multi-UAV Enabled WPCN: A Deep Reinforcement Learning Method
This paper investigates joint unmanned aerial vehicle (UAV) trajectory planning and time resource allocation for minimum throughput maximization in a multiple UAV-enabled wireless powered communication network (WPCN). In particular, the UAVs perform as base stations (BS) to broadcast energy signals in the downlink to charge IoT devices, while the IoT devices send their independent information in the uplink by utilizing the collected energy. The formulated throughput optimization problem which involves joint optimization of 3D path design and channel resource assignment with the constraint of flight speed of UAVs and uplink transmit power of IoT devices, is not convex and thus is extremely difficult to solve directly. We take advantage of the multi-agent deep Q learning (DQL) strategy and propose a novel algorithm to tackle this problem. Simulation results indicate that the proposed DQL-based algorithm significantly improve performance gain in terms of minimum throughput maximization compared with the conventional WPCN scheme
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