176 research outputs found
Power Control for D2D Underlay in Multi-cell Massive MIMO Networks
This paper proposes a new power control and pilot allocation scheme for
device-to-device (D2D) communication underlaying a multi-cell massive MIMO
system. In this scheme, the cellular users in each cell get orthogonal pilots
which are reused with reuse factor one across cells, while the D2D pairs share
another set of orthogonal pilots. We derive a closed-form capacity lower bound
for the cellular users with different receive processing schemes. In addition,
we derive a capacity lower bound for the D2D receivers and a closed-form
approximation of it. Then we provide a power control algorithm that maximizes
the minimum spectral efficiency (SE) of the users in the network. Finally, we
provide a numerical evaluation where we compare our proposed power control
algorithm with the maximum transmit power case and the case of conventional
multi-cell massive MIMO without D2D communication. Based on the provided
results, we conclude that our proposed scheme increases the sum spectral
efficiency of multi-cell massive MIMO networks.Comment: 6 Pages, 3 Figures, WSA 201
An Exclusion zone for Massive MIMO With Underlay D2D Communication
Fifth generation networks will incorporate a variety of new features in
wireless networks such as data offloading, D2D communication, and Massive MIMO.
Massive MIMO is specially appealing since it achieves huge gains while enabling
simple processing like MRC receivers. It suffers, though, from a major
shortcoming refereed to as pilot contamination. In this paper we propose a
frame-work in which, a D2D underlaid Massive MIMO system is implemented and we
will prove that this scheme can reduce the pilot contamination problem while
enabling an optimization of the system spectral efficiency. The D2D
communication will help maintain the network coverage while allowing a better
channel estimation to be performed
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
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