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In this paper, we study the channel selection problem for selfish and altruistic precoding in multilink multiple-input single-output (MISO) networks from a distributed game-theoretic perspective. Our goal is to find for each link a proper channel selection strategy that is robust against time-varying channel states. This motivates the development of stochastic learning that finds Nash equilibrium...
In a dense WLAN deployment, the interfering wireless access points (APs) need to efficiently share the spectrum, and hence, avoid low-performance experience of users due to high collision rates and long backoff overheads. In this paper, we aim to propose a channel assignment scheme in which APs can self-configure their channel choices to mitigate interference and thereby maximize network throughput...
Dynamic Spectrum Access provides novel solutions to improve spectral efficiency. Wireless Service Providers (WSPs) are allowed to transmit data over their exclusive licensed bands and multiple available unlicensed bands. The critical challenge is how to allocate power rationally to prevent severe interference between coexistent users. We formulate the problem as a Users Coexistence Game (UCG) and...
In recent years, Bluetooth low energy (BLE) has become a very popular standard for short range wireless communications. The simplified link control layer and concise packet structure make it very appealing to low power applications with medium data rate requirement. However, the very short preamble of a BLE packet is also present as a new design challenge. In such a burst data communication scenario,...
In this paper, an energy-efficient subchannel and power allocation scheme for a downlink marco-femto heterogeneous network is proposed. The optimization problem which maximizes the energy efficiency of all the FBSs subject to resource allocation constraints is formulated. To solve the formulated NP hard problem, we first apply clustering algorithm, which groups FBSs with interference being lower than...
Heterogeneous networks (HetNets) are expected to be an integral component of expansion of 3G and emerging 4G network deployments. However, in order to achieve the quality-of-service (QoS) requirements of all the users, interference mitigation techniques need to be developed to manage the radio resources of macrocells and small cells. In this paper, we focus on the optimal power allocation for downlink...
This paper addresses the assignment of transmission and sleep time slots between interfering transmitters with the objective of minimal power consumption. In particular, we address the constructive alignment of Discontinuous Transmission (DTX) time slots under link rate constraints. Due to the complexity of the combinatorial optimization problem at hand, we resort to heuristic assignment strategies...
This paper considers distributed linear beamforming in downlink multicell multiuser orthogonal frequency-division multiple access networks. A fast convergent solution maximizing the weighted sum-rate with per base station (BS) transmiting power constraint is formulated. We approximate the noncon-vex weighted sum-rate maximization (WSRM) problem with a semidefinite relaxed solvable convex form by means...
In this paper we examine convergence properties of massive MIMO systems with the aim of determining the number of antennas required for massive MIMO gains. We consider three characteristics of a channel matrix and study their asymptotic behaviour. Furthermore, we derive ZF SNR and MF SINR for a scenario of unequal receive powers. In our results we include the effects of spatial correlation. We show...
In this work, we develop a multi-objective optimization framework for reducing network wide energy consumption through base station (BS) sleep mode (SLM) in an OFDMA based cellular systems. While putting BSs in SLM, we take into account the effects such as coverage and overlap. After putting BSs in SLM, in order to ensure sufficient coverage, overlap (for hand-overs), and to achieve maximum network...
This work addresses the problem of coordinated beamforming in the downlink of an OFDMA cellular network. The figure of merit to be optimized is the global energy efficiency, defined as the ratio between the sum-rate of the coordinated base stations and the corresponding power consumption, under a per-base-station power constraint. The Karush-Kuhn-Tucker (KKT) conditions of the considered optimization...
Device-to-device (D2D) communication, which underlays a cellular network to improve the reuse of spectrum resources, is a promising technique that can increase system capacity, enhance cell coverage and extend battery lifetime of user equipments. In this paper, we study the power allocation for a D2D underlaying cellular network. Our optimization task is to maximize the sum rate of the cellular network...
We introduce an iterative solution to the problem of interference alignment (IA) over MIMO channels based on a message-passing formulation. We propose a parameterization of the messages that enables the computation of IA precoders by a min-sum algorithm over continuous variable spaces — under this parameterization, suitable approximations of the messages can be computed in closed-form. We show that...
We study the problem of interference alignment in the multiple-input multiple-output interference channel. Aiming at minimizing the interference leakage power relative to the receiver noise level, we use the deterministic annealing approach to solve the optimization problem. In the corresponding probabilistic formulation, the precoders and the orthonormal bases of the desired signal subspaces are...
In this paper we consider the problem of data rate maximization of wireless users in multicarrier system in the context of game theory. In such a game, each user maximizes its data rate over all subcarriers while keeping its total transmit power bellow a given threshold. To control the selfish behavior of users we propose a new pricing mechanism whose value depends on transmit power of user as well...
In this work, a joint polarization adaption and beamforming technique is proposed for horizontal spectrum sharing for TD-LTE and FD-LTE users. The polarization and spatial information of multiple dual-polarized antennas on current LTE nodes is exploited to mitigate the mutual interference among the primary, TD-LTE and FD-LTE users. By this means, the opportunities in polarization and spatial domains...
Device-to-device (D2D) communications as an underlay to cellular networks can not only increase the system capacity and energy efficiency, but it can also enable national security and public safety (NSPS) services. A key requirement is to provide access to cellular services when the network is available and maintain local communication in the (partial) absence of the infrastructure. In this paper...
This paper studies distributed interference management for femtocells that share the same frequency band with macrocells. We propose a multi-agent learning technique based on distributed Q-learning, called subcarrier-based distributed resource allocation using Q-learning (SBDRA-Q). SBDRA-Q operates under three different learning paradigms: Independent (IL), Cooperative (CL) and Weighted Cooperative...
In this paper, we consider the uplink subchannel and power allocation problem for device-to-device (D2D) and cellular links in the Orthogonal Frequency Division Multiple Access (OFDMA)-based D2D cellular network. This resource allocation problem aims to maximize the weighted sum throughput of D2D links while guaranteeing the minimum rate of each cellular link. The proposed formulation allows non-orthogonal...
Cognitive heterogeneous networks (HetNets) have been recently introduced as a promising solution to meet the user demand for higher data rate. Due to the physical coexistence of microcells, femtocells and the lack of available spectrum, there is a need for techniques that allows users to share the same spectrum while maintaining required performance level for each user by adopting interference mitigation...
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