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In ultra dense heterogeneous networks (HetNets), the interference becomes more serious since multiple small cells coexist in the coverage area of the macrocells and share the same spectrum. An efficient interference coordination method is adjusting the transmit powers of all cells in a cooperative way. However, under practical serving cell selection rules in which serving cells of users alter with...
This paper considers the optimal power allocation for a multi-band wireless network where links are partially sharing spectrum bands. In this scenario, the power allocation is proposed to maximize the instantaneous sum-rate of the wireless network. For the proposed power allocation, the optimal power allocation factor is derived. Numerical results show the validity of the proposed power allocation.
In this paper, we investigate the energy efficiency maximization problem of analog network coding (ANC) based two-way relay (TWR) assisted cellular network under quality of service (QoS) constraints through transmit power optimization. Circuit power cannot be ignored since it influences energy efficiency greatly. However, the difficulty is that maximizing energy efficiency is shown to be non-convex...
The thresholding methods based on the generalized IRLS iteration are discussed under the complex-valued condition in this paper. An improved IRLS algorithm with double-threshold sigmoid (DTHS) penalty are proposed herein. It is shown that the generalized IRLS algorithm is unbiased if the thresholding penalty can eliminate the undesired perturbation term added on the correlation matrix of the measurement...
Small cells have been identified as an effective solution for coping with the important traffic increase that is expected in the coming years. But this solution is accompanied by additional interference that needs to be mitigated. The enhanced Inter Cell Interference Coordination (eICIC) feature has been introduced to address the interference problem. eICIC involves two parameters which need to be...
We present a novel low-complexity technique that obtains the Physical-Layer Network Coding (PNC) equation coefficient vectors for the two-way relay channel when Compute-and-Forward is employed. The proposed method is based on pre-computed look-up tables that are used for all channel realizations. It is shown that the size of the look-up tables can be made small by taking into account the statistics...
A mathematical model was developed to investigate the membrane dehydration which appears at the anode side of the membrane by varying various operating parameters like fuel cell operating temperature, anode humidification temperature and anode stoichiometry. Taguchi optimization methodology is then combined with this model to determine the optimal combination of the operating parameters to maximize...
We present optimization algorithms for source and relay power allocations for a multicarrier three-node relay system with direct link. We show that there is a benefit to the system capacity by allowing the source power to be split in both phases in a two-phase relay scheme. While the source power allocation problem is convex, the relay power allocation problem is not. But in both cases, we present...
The problem of optimally adjusting the power spectral density level, referred as power spectrum optimization, is a well-known and difficult nonconvex optimization problem. This paper investigates a class of local optimization methods based on a technique called iterative function evaluation. This idea, first proposed in our previous work, is based on the manipulation of the first order condition of...
This article develops a unified analytical framework for maximizing the user throughput of a cooperative multi-relay network over generalized wireless channels using the symbol rate, packet length and constellation size of M-ary PSK/QAM digital modulation schemes as optimization variables. Optimization equations for each of the above degrees of freedom are derived in closed-form. A low-complexity...
The joint optimization of power allocation and relay position is known to be a frightening problem in the analysis of cooperative relay communication. In this article, we present an efficient framework that tackles this problem for 2-hop cooperative amplify-and-forward (CAF) multi-relay system over generalized fading channel. First, we consider single CAF relay where we investigate (i) the optimum...
In recent years, cognitive radio technology (CR) has been proposed to allow unlicensed secondary users (SUs) to opportunistically access the channels unused by primary users. As a result, there is a lot of recent interests on studying cognitive radio cellular networks (CogCells) that can support both PUs and SUs. Due to the limited transmission range of SUs, in this work we consider supporting Multi-hop...
Energy-efficient link adaptation is studied on a slowly varying Rayleigh fading channel assuming perfect CSI at the receiver but no CSI at the transmitter, except for the statistical characterization. Both circuit power and power dissipated in the power amplifier are considered and the energy consumption per bit is minimized over bandwidth, transmission power, and transmission rate. It is shown that...
In this paper, we study an achievable rate region of the two-user multiple-input single-output (MISO) interference channel. We find the transmit beamforming vectors that achieve Pareto-optimal points. We do so, by deriving a sufficient condition for Pareto optimality. Given the beamforming vector of one transmitter, this condition enables us to determine the beamforming vector of the other transmitter...
We analytically allocate to sub-channels costly power and symbol rate to maximise a general throughput function. Link parameters (e.g., modulation order and packet length) are explicitly considered. We provide the structure of the general solution, and for certain scenarios give an explicit solution, which includes the optimal link configuration. A channel can be immediately discarded if its normalised...
This paper takes into account the uncertainty of the primary users' locations and transmission power in designing an optimal downlink scheduling scheme for cognitive radio cellular networks (CogCells). Localization technique is exploited to estimate the position and transmission power of the primary user (PU) transmitting on specific channel. The objective of our scheduling scheme is to maximize the...
Identification of a nonlinear model is a main topic of modern identification. It is presented that a new approach to parameters estimation for one type of nonlinear models (Wiener model) by using improved bacterial foraging optimization (IBFO) algorithm. Firstly, the basic principle of bacterial foraging optimization (BFO) algorithm is introduced, and then proposed an IBFO. Parameters estimation for...
The Planning Aid for Tasking Heterogeneous Assets (PATHA) is a decision support tool that addresses shortcomings in current route survey or naval mine countermeasures mission planning capabilities. The tool is able to optimally assign heterogeneous assets to segments in an area of interest. Track positions for each allocation are also determined by PATHA, in order to give optimal coverage in each...
The similarity and differences of two groups of non-stationary system are considered. The first group contains the measuring systems, the output signal of which suffered decrease due to non-stationary feature of attenuation coefficient of media in which the signal carrier is propagated. The second group contains the measuring system, the signal / noise ratio at output of which may be increased by...
In this paper, we revisit the problem of signal detection in multipath scattering. Specifically, we explore the effect of bandwidth and signaling duration on non-coherent signal detection in doubly dispersive non-uniform multipath scattering environments. In such environments, we conjecture that detection performance is optimized if two conditions are met: C1) the number of independent degrees of...
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