940 research outputs found
Coalitions in Cooperative Wireless Networks
Cooperation between rational users in wireless networks is studied using
coalitional game theory. Using the rate achieved by a user as its utility, it
is shown that the stable coalition structure, i.e., set of coalitions from
which users have no incentives to defect, depends on the manner in which the
rate gains are apportioned among the cooperating users. Specifically, the
stability of the grand coalition (GC), i.e., the coalition of all users, is
studied. Transmitter and receiver cooperation in an interference channel (IC)
are studied as illustrative cooperative models to determine the stable
coalitions for both flexible (transferable) and fixed (non-transferable)
apportioning schemes. It is shown that the stable sum-rate optimal coalition
when only receivers cooperate by jointly decoding (transferable) is the GC. The
stability of the GC depends on the detector when receivers cooperate using
linear multiuser detectors (non-transferable). Transmitter cooperation is
studied assuming that all receivers cooperate perfectly and that users outside
a coalition act as jammers. The stability of the GC is studied for both the
case of perfectly cooperating transmitters (transferrable) and under a partial
decode-and-forward strategy (non-transferable). In both cases, the stability is
shown to depend on the channel gains and the transmitter jamming strengths.Comment: To appear in the IEEE Journal on Selected Areas in Communication,
Special Issue on Game Theory in Communication Systems, 200
A Distributed Merge and Split Algorithm for Fair Cooperation in Wireless Networks
This paper introduces a novel concept from coalitional game theory which
allows the dynamic formation of coalitions among wireless nodes. A simple and
distributed merge and split algorithm for coalition formation is constructed.
This algorithm is applied to study the gains resulting from the cooperation
among single antenna transmitters for virtual MIMO formation. The aim is to
find an ultimate transmitters coalition structure that allows cooperating users
to maximize their utilities while accounting for the cost of coalition
formation. Through this novel game theoretical framework, the wireless network
transmitters are able to self-organize and form a structured network composed
of disjoint stable coalitions. Simulation results show that the proposed
algorithm can improve the average individual user utility by 26.4% as well as
cope with the mobility of the distributed users.Comment: This paper is accepted for publication at the IEEE ICC Workshop on
Cooperative Communications and Networkin
Coalitional Games in MISO Interference Channels: Epsilon-Core and Coalition Structure Stable Set
The multiple-input single-output interference channel is considered. Each
transmitter is assumed to know the channels between itself and all receivers
perfectly and the receivers are assumed to treat interference as additive
noise. In this setting, noncooperative transmission does not take into account
the interference generated at other receivers which generally leads to
inefficient performance of the links. To improve this situation, we study
cooperation between the links using coalitional games. The players (links) in a
coalition either perform zero forcing transmission or Wiener filter precoding
to each other. The -core is a solution concept for coalitional games
which takes into account the overhead required in coalition deviation. We
provide necessary and sufficient conditions for the strong and weak
-core of our coalitional game not to be empty with zero forcing
transmission. Since, the -core only considers the possibility of
joint cooperation of all links, we study coalitional games in partition form in
which several distinct coalitions can form. We propose a polynomial time
distributed coalition formation algorithm based on coalition merging and prove
that its solution lies in the coalition structure stable set of our coalition
formation game. Simulation results reveal the cooperation gains for different
coalition formation complexities and deviation overhead models.Comment: to appear in IEEE Transactions on Signal Processing, 14 pages, 14
figures, 3 table
Coalitional Games for Transmitter Cooperation in MIMO Multiple Access Channels
Cooperation between nodes sharing a wireless channel is becoming increasingly
necessary to achieve performance goals in a wireless network. The problem of
determining the feasibility and stability of cooperation between rational nodes
in a wireless network is of great importance in understanding cooperative
behavior. This paper addresses the stability of the grand coalition of
transmitters signaling over a multiple access channel using the framework of
cooperative game theory. The external interference experienced by each TX is
represented accurately by modeling the cooperation game between the TXs in
\emph{partition form}. Single user decoding and successive interference
cancelling strategies are examined at the receiver. In the absence of
coordination costs, the grand coalition is shown to be \emph{sum-rate optimal}
for both strategies. Transmitter cooperation is \emph{stable}, if and only if
the core of the game (the set of all divisions of grand coalition utility such
that no coalition deviates) is nonempty. Determining the stability of
cooperation is a co-NP-complete problem in general. For a single user decoding
receiver, transmitter cooperation is shown to be \emph{stable} at both high and
low SNRs, while for an interference cancelling receiver with a fixed decoding
order, cooperation is stable only at low SNRs and unstable at high SNR. When
time sharing is allowed between decoding orders, it is shown using an
approximate lower bound to the utility function that TX cooperation is also
stable at high SNRs. Thus, this paper demonstrates that ideal zero cost TX
cooperation over a MAC is stable and improves achievable rates for each
individual user.Comment: in review for publication in IEEE Transactions on Signal Processin
MIMO-OFDM Based Energy Harvesting Cooperative Communications Using Coalitional Game Algorithm
This document is the Accepted Manuscript version. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, we consider the problem of cooperative communication between relays and base station in an advanced MIMO-OFDM framework, under the assumption that the relays are supplied by electric power drawn from energy harvesting (EH) sources. In particular, we focus on the relay selection, with the goal to guarantee the required performance in terms of capacity. In order to maximize the data throughput under the EH constraint, we model the transmission scheme as a non-transferable coalition formation game, with characteristic function based on an approximated capacity expression. Then, we introduce a powerful mathematical tool inherent to coalitional game theory, namely: the Shapley value (Sv) to provide a reliable solution concept to the game. The selected relays will form a virtual dynamically-configuredMIMO network that is able to transmit data to destination using efficient space-time coding techniques. Numerical results, obtained by simulating the EH-powered cooperativeMIMO-OFDMtransmission with Algebraic Space-Time Coding (ASTC), prove that the proposed coalitional game-based relay selection allows to achieve performance very close to that obtained by the same system operated by guaranteed power supply. The proposed methodology is finally compared with some recent related state-of-the-art techniques showing clear advantages in terms of link performance and goodput.Peer reviewe
Coalitional Games with Overlapping Coalitions for Interference Management in Small Cell Networks
In this paper, we study the problem of cooperative interference management in
an OFDMA two-tier small cell network. In particular, we propose a novel
approach for allowing the small cells to cooperate, so as to optimize their
sum-rate, while cooperatively satisfying their maximum transmit power
constraints. Unlike existing work which assumes that only disjoint groups of
cooperative small cells can emerge, we formulate the small cells' cooperation
problem as a coalition formation game with overlapping coalitions. In this
game, each small cell base station can choose to participate in one or more
cooperative groups (or coalitions) simultaneously, so as to optimize the
tradeoff between the benefits and costs associated with cooperation. We study
the properties of the proposed overlapping coalition formation game and we show
that it exhibits negative externalities due to interference. Then, we propose a
novel decentralized algorithm that allows the small cell base stations to
interact and self-organize into a stable overlapping coalitional structure.
Simulation results show that the proposed algorithm results in a notable
performance advantage in terms of the total system sum-rate, relative to the
noncooperative case and the classical algorithms for coalitional games with
non-overlapping coalitions
Game-theoretic Resource Allocation Methods for Device-to-Device (D2D) Communication
Device-to-device (D2D) communication underlaying cellular networks allows
mobile devices such as smartphones and tablets to use the licensed spectrum
allocated to cellular services for direct peer-to-peer transmission. D2D
communication can use either one-hop transmission (i.e., in D2D direct
communication) or multi-hop cluster-based transmission (i.e., in D2D local area
networks). The D2D devices can compete or cooperate with each other to reuse
the radio resources in D2D networks. Therefore, resource allocation and access
for D2D communication can be treated as games. The theories behind these games
provide a variety of mathematical tools to effectively model and analyze the
individual or group behaviors of D2D users. In addition, game models can
provide distributed solutions to the resource allocation problems for D2D
communication. The aim of this article is to demonstrate the applications of
game-theoretic models to study the radio resource allocation issues in D2D
communication. The article also outlines several key open research directions.Comment: Accepted. IEEE Wireless Comms Mag. 201
Improving Macrocell - Small Cell Coexistence through Adaptive Interference Draining
The deployment of underlay small base stations (SBSs) is expected to
significantly boost the spectrum efficiency and the coverage of next-generation
cellular networks. However, the coexistence of SBSs underlaid to an existing
macro-cellular network faces important challenges, notably in terms of spectrum
sharing and interference management. In this paper, we propose a novel
game-theoretic model that enables the SBSs to optimize their transmission rates
by making decisions on the resource occupation jointly in the frequency and
spatial domains. This procedure, known as interference draining, is performed
among cooperative SBSs and allows to drastically reduce the interference
experienced by both macro- and small cell users. At the macrocell side, we
consider a modified water-filling policy for the power allocation that allows
each macrocell user (MUE) to focus the transmissions on the degrees of freedom
over which the MUE experiences the best channel and interference conditions.
This approach not only represents an effective way to decrease the received
interference at the MUEs but also grants the SBSs tier additional transmission
opportunities and allows for a more agile interference management. Simulation
results show that the proposed approach yields significant gains at both
macrocell and small cell tiers, in terms of average achievable rate per user,
reaching up to 37%, relative to the non-cooperative case, for a network with
150 MUEs and 200 SBSs
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