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Recently, compressed sensing (CS) is of major interest in the area of communication and measurement. CS technique is a subtle mathematical application in practice, which facilitates the signal acquisition and signal processing dramatically. It consists of the two phases: signal projection and signal recovery. Regarding the signal recovery often it is an l1 optimization process in terms of a sparse...
This paper considers the problem of energy efficiency maximization in the uplink of a cluster of multiple-antenna coordinated access points. A framework for energy efficiency optimization is developed in which the signal-to-interference-plus-noise ratio takes a more general expression than existing alternatives so as to encompass most 5G candidate technologies. Two energy efficiency optimization problems...
In this paper, we propose a power control algorithm for uplink and downlink multi-cell massive MIMO systems, where channel estimation error, pilot contamination and correlated channels are taken into account. Moreover, a closed-form power control algorithm under the assumption of equal power allocation for multiple users is provided. The simulation results show that equal power allocation is near...
This paper studies the spectrum sharing framework for motivating the hybrid access in the two-tier macro-femtocell networks. The power allocation of each user equipment (UE) is subject to its quality-of-service (QoS) requirement as a function of the signal-to-interference plus noise ratio (SINR). The macro base station (MBS) offloads the macro UEs (MUEs) to the femto access points (FAPs) in order...
In this paper we study secure communications with weak secrecy constraint in a cognitive radio channel, where the secondary receiver is treated as a potential eavesdropper with respect to the primary transmission. The primary's secrecy rate and the transmission scheme should be kept unchanged whether the secondary users transmit or not. We derive the achievable rate of the discrete memoryless multi-phase...
When there are strategic and malicious users in a wireless network, the resource allocation is complicated due to the information limitation about the nature of users and network parameters. Bayesian games are appropriate tools to analyze the network resource allocation with heterogeneous users. We consider a scenario with arbitrary number of malicious users in the network, in which individual users...
In this work, we focus on two problems related to the rate fairness based SLAs (Service Level Agreements) in an environment where multiple operators are sharing the spectrum. At first we show analytically that achieving rate fairness among arbitrary number of operators on the smallest time-frequency radio resource (e.g. one OFDM resource element) is feasible. Then we transform the problem of rate...
Research on 5G mobile wireless technologies has been very active in both academia and industry in the past few years. While there has been certain consensus on the overall requirements of 5G wireless systems (e.g., in data rate, network capacity, delay), various enabling wireless technologies have been considered and studied to achieve these performance targets. It has been quite clear, however, that...
Network sharing is one of the solutions for mobile operators to improve spectral efficiency and enhance coverage with smaller operational and investment costs. In this work, we propose a novel solution based on the multi-user MIMO approach for the network sharing among multiple operators. We use multiple antennas for spatial multiplexing of multiple operators on the smallest possible radio resource...
We consider a wireless communication scenario where two agents aim at agreeing on a secret key, while leaving a passive eavesdropper in the darkness. All terminals are equipped with multiple antennas resulting in a multiple input multiple output (MIMO) scenario with reciprocal correlated flat Rayleigh fading channels among antenna couples. Correlation properties are known to all agents. In order to...
In this paper we investigate the cooperative secure communication in a four-node cognitive channel where the secondary receiver is treated as a potential eavesdropper with respect to the primary transmission with variational distance constraint. And the primary user's secrecy rate is required to be unchanged. We propose the clean relaying with the cooperative jamming scheme to achieve this goal, where...
Dense Cooperative Wireless Cloud Network (DIWINE) FP7 project introduces a new wireless cloud network, where the interference interaction is an advantage rather than a limitation. The cloud consists of dense massively air-interacting nodes, that provide a simple and uniform PHY interface to the clients. In this work we consider the Massive Interference (MI) scenario for the DIWINE network, where the...
In this paper we partially characterize the relation between the ergodic secrecy capacity of fast fading wiretap channels and the stochastic orders including the usual stochastic orders, the convex orders, and the increasing convex orders, of the main and eavesdropper's channels. We assume that there is only statistical channel state information of both channels at transmitter and both fading channels...
In this work, the issue of non-cooperative resource allocation in the uplink of a relay-assisted MIMO MAC (multiple input multiple output multiple access channel) system with statistical CSI (channel state information) is considered. The mobile transmitters pursue individual achievable ergodic rate maximization, whereas the relay aims at optimizing the global performance of the system. The problem...
We consider the limited feedback problem in a multi-cell spatially-correlated massive MIMO frequency division duplexing (FDD) system. The very high dimension of massive MIMO channels makes the limited feedback schemes in traditional MIMO inefficient. This motivates us to explore a novel approach to reduce the feedback overhead in two stages: 1) The original channel vector is sparsified in the spatial...
In this paper we consider a multi-pair two-way relaying network with two types of relays, namely, smart multi-antenna amplify and forward relays and dumb repeaters. The smart relays are able to perform adaptive linear precoding while the dumb repeaters are only able to forward the received signals. Utilizing an interference neutralization scheme, a closed-form transmit strategy can be computed for...
Green resource allocation in an amplify-and-forward (AF) relay-assisted MIMO system is considered, consisting of one source, one AF relay, and one destination, in which the relay-to-destination channel is only statistically known to the source and relay. The source covariance matrix and the relay AF matrix are optimized so as to maximize the system energy efficiency (EE), defined as the ratio of the...
We consider a multi-cell interfering MIMO-MAC system, where each user transmits a single data stream to its desired base station (BS). First, we study the multiplexing gain of the system using two interference cancellation (IC) schemes: the coordinated zero-forcing receiver (CZFR) and the extended grouping method based IA (EGM-IA) with the perfect channel state information at transmitters (CSIT)....
We develop the noncooperative game with individual pricing for the general multiple access channel (MAC) system without successive interference cancellation (SIC). Each user allocates its own power by optimizing the individual utility function with clever price adaptation. We show that by the proposed prices, the best response (BR) power allocation of each user converges rapidly. The individual prices...
In this paper, we study the problems of power allocation in a multi-user relay-assisted wireless network. From the perspective of game theory, we formulate and analyze this power allocation problem as a power trading game by considering users as bidders and the relay as an auctioneer. Aiming at solving this problem where each bidder has a private budget limit, we apply an adaptive clinching auction...
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