107 research outputs found
Cell Selection in Wireless Two-Tier Networks: A Context-Aware Matching Game
The deployment of small cell networks is seen as a major feature of the next
generation of wireless networks. In this paper, a novel approach for cell
association in small cell networks is proposed. The proposed approach exploits
new types of information extracted from the users' devices and environment to
improve the way in which users are assigned to their serving base stations.
Examples of such context information include the devices' screen size and the
users' trajectory. The problem is formulated as a matching game with
externalities and a new, distributed algorithm is proposed to solve this game.
The proposed algorithm is shown to reach a stable matching whose properties are
studied. Simulation results show that the proposed context-aware matching
approach yields significant performance gains, in terms of the average utility
per user, when compared with a classical max-SINR approach.Comment: 11 pages, 11 figures, Journal article in ICST Wireless Spectrum, 201
Orthogonal Code Design for MIMO Amplify-and-Forward Cooperative Networks
This paper is on the design of practical distributed space-time codes for wireless relay networks with multiple antennas terminals. The amplify-and-forward scheme is used in a way that each relay transmits a scaled version of the linear combination of the received symbols. We propose distributed orthogonal space-time codes which are distributed among the source node's antennas and relays. Using linear orthogonal decoding in the destination makes it feasible to employ large number of potential relays to improve the diversity order. Assuming multiple amplitude modulation, we derive a formula for the symbol error probability of the investigated scheme over Rayleigh fading channels. Our analytical results have been confirmed by simulation results, using full-rate, full-diversity distributed codes
A Colonel Blotto Game for Interdependence-Aware Cyber-Physical Systems Security in Smart Cities
Smart cities must integrate a number of interdependent cyber-physical systems
that operate in a coordinated manner to improve the well-being of the city's
residents. A cyber-physical system (CPS) is a system of computational elements
controlling physical entities. Large-scale CPSs are more vulnerable to attacks
due to the cyber-physical interdependencies that can lead to cascading failures
which can have a significant detrimental effect on a city. In this paper, a
novel approach is proposed for analyzing the problem of allocating security
resources, such as firewalls and anti-malware, over the various cyber
components of an interdependent CPS to protect the system against imminent
attacks. The problem is formulated as a Colonel Blotto game in which the
attacker seeks to allocate its resources to compromise the CPS, while the
defender chooses how to distribute its resources to defend against potential
attacks. To evaluate the effects of defense and attack, various CPS factors are
considered including human-CPS interactions as well as physical and topological
characteristics of a CPS such as flow and capacity of interconnections and
minimum path algorithms. Results show that, for the case in which the attacker
is not aware of the CPS interdependencies, the defender can have a higher
payoff, compared to the case in which the attacker has complete information.
The results also show that, in the case of more symmetric nodes, due to
interdependencies, the defender achieves its highest payoff at the equilibrium
compared to the case with independent, asymmetric nodes
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