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Full-Text Articles in Engineering

Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo Oct 2013

Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo

Mingyi Hong

In a wireless system with a large number of distributed nodes, the quality of communication can be greatly improved by pooling the nodes to perform joint transmission/reception. In this paper, we consider the problem of optimally selecting a subset of nodes from potentially a large number of candidates to form a virtual multi-antenna system, while at the same time designing their joint linear transmission strategies. We focus on two specific application scenarios: 1) multiple single antenna transmitters cooperatively transmit to a receiver; 2) a single transmitter transmits to a receiver with the help of a number of cooperative relays. We …


Joint Access Point Selection And Power Allocation For Uplink Wireless Networks, Mingyi Hong, Alfredo Garcia, Jorge Barrera, Stephen G. Wilson Jul 2013

Joint Access Point Selection And Power Allocation For Uplink Wireless Networks, Mingyi Hong, Alfredo Garcia, Jorge Barrera, Stephen G. Wilson

Mingyi Hong

We consider the distributed uplink resource allocation problem in a multi-carrier wireless network with multiple access points (APs). Each mobile user can optimize its own transmission rate by selecting a suitable AP and by controlling its transmit power. Our objective is to devise suitable algorithms by which mobile users can jointly perform these tasks in a distributed manner. Our approach relies on a game theoretic formulation of the joint power control and AP selection problem. In the proposed game, each user is a player with an associated strategy containing a discrete variable (the AP selection decision) and a continuous vector …


Distributed Linear Precoder Optimization And Base Station Selection For An Uplink Heterogeneous Network, Mingyi Hong, Zhi-Quan Luo Jun 2013

Distributed Linear Precoder Optimization And Base Station Selection For An Uplink Heterogeneous Network, Mingyi Hong, Zhi-Quan Luo

Mingyi Hong

In a heterogeneous wireless cellular network, each user may be covered by multiple access points such as macro/pico/relay/femto base stations (BS). An effective approach to maximize the sum utility (e.g., system throughput) in such a network is to jointly optimize users' linear procoders as well as their BS associations. In this paper, we first show that this joint optimization problem is NP-hard and thus is difficult to solve to global optimality. To find a locally optimal solution, we formulate the problem as a noncooperative game in which the users and the BSs both act as players. We introduce a set …


Joint Base Station Clustering And Beamformer Design For Partial Coordinated Transmission In Heterogeneous Networks, Mingyi Hong, Ruoyu Sun, Hadi Baligh, Zhi-Quan Luo Feb 2013

Joint Base Station Clustering And Beamformer Design For Partial Coordinated Transmission In Heterogeneous Networks, Mingyi Hong, Ruoyu Sun, Hadi Baligh, Zhi-Quan Luo

Mingyi Hong

We consider the interference management problem in a multicell MIMO heterogeneous network. Within each cell there is a large number of distributed micro/pico base stations (BSs) that can be potentially coordinated for joint transmission. To reduce coordination overhead, we consider user-centric BS clustering so that each user is served by only a small number of (potentially overlapping) BSs. Thus, given the channel state information, our objective is to jointly design the BS clustering and the linear beamformers for all BSs in the network. In this paper, we formulate this problem from a {sparse optimization} perspective, and propose an efficient algorithm …


Derivative Estimation With Local Polynomial Fitting, Kris De Brabanter, Jos De Brabanter, Bart De Moor, Irene Gijbels Jan 2013

Derivative Estimation With Local Polynomial Fitting, Kris De Brabanter, Jos De Brabanter, Bart De Moor, Irene Gijbels

Kris De Brabanter

We present a fully automated framework to estimate derivatives nonparametrically without estimating the regression function. Derivative estimation plays an important role in the exploration of structures in curves (jump detection and discontinuities), comparison of regression curves, analysis of human growth data, etc. Hence, the study of estimating derivatives is equally important as regression estimation itself. Via empirical derivatives we approximate the qth order derivative and create a new data set which can be smoothed by any nonparametric regression estimator. We derive L1 and L2 rates and establish consistency of the estimator. The new data sets created by this technique are …


Empirical Data And Regression Analysis For Estimation Of Infrastructure Resilience With Application To Electric Power Outages, Cameron A. Mackenzie, Kash Barker Jan 2013

Empirical Data And Regression Analysis For Estimation Of Infrastructure Resilience With Application To Electric Power Outages, Cameron A. Mackenzie, Kash Barker

Cameron A. MacKenzie

Recent natural disasters have highlighted the need for increased planning for disruptive events. Forecasting damage and time that a system will be inoperable is important for disruption planning. The resilience of critical infrastructure systems, or their ability to recover quickly from a disruption, can mitigate adverse consequences of the disruption. This paper quantifies the resilience of a critical infrastructure sector through the dynamic inoperability input-output model (DIIM). The DIIM, which describes how inoperability propagates through a set of interdependent industry and infrastructure sectors following a disruptive event, includes a resilience parameter that has not yet been adequately assessed. This paper …


Linear Transceiver Design For A Mimo Interfering Broadcast Channel Achieving Max–Min Fairness, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo Jan 2013

Linear Transceiver Design For A Mimo Interfering Broadcast Channel Achieving Max–Min Fairness, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo

Mingyi Hong

This problem can be formulated as maximizing the minimum rate among all the users in an interfering broadcast channel (IBC). In this paper we show that when the number of antennas is at least two at each of the transmitters and the receivers, the min rate maximization problem is NP-hard in the number of users. Moreover, we develop a low-complexity algorithm for this problem by iteratively solving a sequence of convex subproblems. We theoretically establish the global convergence of the proposed algorithm to the set of stationary points, which may be suboptimal due to the non-convexity of the original minimum …