22,423 research outputs found
Downlink Power Control in User-Centric and Cell-Free Massive MIMO Wireless Networks
Recently, the so-called cell-free Massive MIMO architecture has been
introduced, wherein a very large number of distributed access points (APs)
simultaneously and jointly serve a much smaller number of mobile stations
(MSs). A variant of the cell-free technique is the user-centric approach,
wherein each AP just decodes the MSs that it receives with the largest power.
This paper considers both the cell-free and user-centric approaches, and, using
an interplay of sequential optimization and alternating optimization, derives
downlink power-control algorithms aimed at maximizing either the minimum users'
SINR (to ensure fairness), or the system sum-rate. Numerical results show the
effectiveness of the proposed algorithms, as well as that the user-centric
approach generally outperforms the CF one.Comment: presented at the 28th Annual IEEE International Symposium on
Personal, Indoor and Mobile Radio Communications (IEEE PIMRC 2017), Montreal
(CA), October 201
Privacy Games: Optimal User-Centric Data Obfuscation
In this paper, we design user-centric obfuscation mechanisms that impose the
minimum utility loss for guaranteeing user's privacy. We optimize utility
subject to a joint guarantee of differential privacy (indistinguishability) and
distortion privacy (inference error). This double shield of protection limits
the information leakage through obfuscation mechanism as well as the posterior
inference. We show that the privacy achieved through joint
differential-distortion mechanisms against optimal attacks is as large as the
maximum privacy that can be achieved by either of these mechanisms separately.
Their utility cost is also not larger than what either of the differential or
distortion mechanisms imposes. We model the optimization problem as a
leader-follower game between the designer of obfuscation mechanism and the
potential adversary, and design adaptive mechanisms that anticipate and protect
against optimal inference algorithms. Thus, the obfuscation mechanism is
optimal against any inference algorithm
eIDeCert: a user-centric solution for mobile identification
The necessity to certify one's identity for different purposes and the evolution of mobile technologies have led to the generation of electronic devices such as smart cards, and electronic identities designed to meet daily needs. Nevertheless, these mechanisms have a problem: they don't allow the user to set the scope of the information presented. That problem introduces interesting security and privacy challenges and requires the development of a new tool that supports user-centrity for the information being handled. This article presents eIDeCert, a tool for the management of electronic identities (eIDs) in a mobile environment with a user-centric approach. Taking advantage of existing eCert technology we will be able to solve a real problem. On the other hand, the application takes us to the boundary of what the technology can cope with: we will assess how close we are to the boundary, and we will present an idea of what the next step should be to enable us to reach the goal
User-centric distributed solutions for privacy-preserving analytics
How can cryptography empower users with sensitive data to access large-scale computing platforms in a privacy-preserving manner?</jats:p
Energy-Efficient Downlink Power Control in mmWave Cell-Free and User-Centric Massive MIMO
This paper considers cell-free and user-centric approaches for coverage
improvement in wireless cellular systems operating at millimeter wave
frequencies, and proposes downlink power control algorithms aimed at maximizing
the global energy efficiency. To tackle the non-convexity of the problems, an
interaction between sequential and alternating optimization is considered. The
use of hybrid analog/digital beamformers is also taken into account. The
numerical results show the benefits obtained from the power control algorithm,
as well as that the user-centric approach generally outperforms the cell-free
one.Comment: 4 pages; to be presented at the IEEE 5G Worls Forum Conference, Santa
Clara, July 2018. arXiv admin note: text overlap with arXiv:1710.0781
Energy-Efficient Power Control: A Look at 5G Wireless Technologies
This work develops power control algorithms for energy efficiency (EE)
maximization (measured in bit/Joule) in wireless networks. Unlike previous
related works, minimum-rate constraints are imposed and the
signal-to-interference-plus-noise ratio takes a more general expression, which
allows one to encompass some of the most promising 5G candidate technologies.
Both network-centric and user-centric EE maximizations are considered. In the
network-centric scenario, the maximization of the global EE and the minimum EE
of the network are performed. Unlike previous contributions, we develop
centralized algorithms that are guaranteed to converge, with affordable
computational complexity, to a Karush-Kuhn-Tucker point of the considered
non-convex optimization problems. Moreover, closed-form feasibility conditions
are derived. In the user-centric scenario, game theory is used to study the
equilibria of the network and to derive convergent power control algorithms,
which can be implemented in a fully decentralized fashion. Both scenarios above
are studied under the assumption that single or multiple resource blocks are
employed for data transmission. Numerical results assess the performance of the
proposed solutions, analyzing the impact of minimum-rate constraints, and
comparing the network-centric and user-centric approaches.Comment: Accepted for Publication in the IEEE Transactions on Signal
Processin
- …