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In wireless networks, providing a high fairness allocation isbecoming a very challenging task. This paper has two objectives:firstly, we proposed a new optimization problem called SatisfactionProbability which consists in maximizing the number of satisfiedusers and secondly, we proposed a new scheduling scheme calledQoE-aware Multi-step Opportunistic (QEMO) scheduler. QEMO is builtin an extended cross-layer...
Energy-efïîdent planning is a current challenge for heterogeneous 4g wireless networks, since ‘greener’ strategies typically act against the always growing traffic requirements. However, network-wide optimization of base station antenna patterns can be exploited to that end, leading the total transmit power of the network to a global minimum. This article formulates the coverage and capacity optimization...
The problem of bi-objective radar waveform design for target detection with stopband constraint is addressed in this paper. Two objective functions, namely, the receiver output signal-to-interference-plus-noise ratio (SINR) and the spectral power of the transmitted waveform in certain frequency bands are used as the criteria. Both energy constraint and modulus constraint are applied to the waveform...
In this paper, we study the optimization of resource allocation in dual-hop relay assisted multi-user sparse code multiple access (SCMA) uplink network. Based on this, an uplink transmission strategy with the combination of SCMA and orthogonal frequency division multiple access (OFDMA) is considered, where the user equipments (UEs) transmit information to a relay station (RS) via SCMA codebook assignment...
This paper studies the problem of distributed parameter estimation in wireless sensor network under energy constraints. Optimization formulas that guarantee the best estimation performance from the available energy are derived. The network consists of sensors that are deployed over an area at random. Sensors' observations are noisy measurements of an underlying field. Sensors have limited energy for...
In this work, we solve a problem of antenna selection (AS) for a multiple-input multiple-output (MIMO) system under the constraint of the channel capacity maximization. The biogeography-based optimization (BBO) algorithm is applied on the joint transmitter and receiver AS for the channel capacity function. We apply different BBO migration models for simulated channels. The comparisons with other popular...
The resource allocation problem is investigated for an Uplink OFDMA based system. The subcarrier and power allocation issue was formulated as an optimization problem with the objective of maximizing the overall system rate, and maintaining a minimum rate for every user, so that fairness is addressed. Two level dual decomposition algorithm was adopted to derive the optimal power and subcarrier, while...
In the era of sustainability, recycling of industrial waste material by using marble powder as filler in the Polypropylene matrix recommend an interesting opportunity. In this study, composites were fabricated by adding different weight percentages of marble powder (5–15 wt.%) in the Polypropylene by injection molding process. To evaluate the contribution of marble powder in the PP-marble composite,...
The study was aimed at evaluating the value of current modulation (mAs) and iterative reconstructions algorithms during Computed Tomography examinations in terms of dose reduction and image quality. The focus was mainly on non-contrast head and chest-abdomen-pelvis examinations. A total of 40 adult patients with weighting between 65 and 80 kg underwent CT examinations (20 head and 20 chest-abdomen-pelvis)...
Weighted queue minimization is considered in Dynamic TDD system where the available resources per cell and per TDD frame can be freely allocated to both uplink (UL) and downlink (DL) transmission depending on traffic demand and user distribution within the network. Given the traffic state, joint UL/DL cell mode selection, beamformer design and resource allocation among available time/frequency/space...
Energy-efficient design has emerged as a promising technique in heterogeneous networks. We study the energy efficiency problem of joint user association and power allocation in a two-tier heterogeneous network with small cells. The energy efficiency is maximized under certain prescribed quality-of-service requirement and maximum power limit constraint. The original optimization problem is a nonconvex...
This paper presents a novel technique to extend the bandwidth of oversampled Analog-to-Digital Converters and a method to optimize their design to avoid instability, when oversampling has to be preserved and clock frequency cannot be increased. This proposal allows the converter to increase the resolution only introducing minor circuit modifications when processing input signals in the extended band...
Abstract-In this paper, the problem of designing a linear precoder for Multiple-Input Multiple-Output (MIMO) systems in conjunction with Quadrature Amplitude Modulation (QAM) is addressed. First, a novel and efficient methodology to evaluate the input-output mutual information for a general Multiple-Input Multiple-Output (MIMO) system as well as its corresponding gradients is presented, based on the...
The femtocell network has currently been considered as one of the most promising networking technologies. Nevertheless, due to dense deployment, interference generated by nearby femto base station (FBS) is expected to significantly degrade the signal to interference plus noise ratio (SINR) of femto users (FUEs). Ineffective resource block combination is one of the culprits behind the reduction in...
Abstract-We consider the problem of designing constellation sets for multistage systems for high spectral efficiencies. In particular we will focus on two-stage systems where the cascaded decoding stages are associated to three types of receivers with different complexities and performances. The optimal receiver (S) processes the symbol LLR and delivers the maximum possible throughput, the simpler...
Heterogeneous wireless networks (HetNets) provide a powerful approach to meet the dramatic mobile traffic growth, but also impose a significant challenge on backhaul. Caching and multicasting at macro and pico base stations (BSs) are two promising methods to support massive content delivery and reduce backhaul load in HetNets. In this paper, we jointly consider caching and multicasting in a large-scale...
This paper addresses the problem of maximizing the weighted signal-to-interference-plus-noise-ratio (SINR) targets at user terminals in a distributed manner in multicell interference networks. The optimization is constrained to strict individual base station (BS) transmit power limitations in the presence of imperfect channel state information (CSI). This problem is numerically intractable due to...
This paper presents the analysis and hardware implementation of a low-power control system for a frequency-division duplexing 3G receiver with a tunable on-chip duplexer based on a hybrid-transformer. The maximum transmit-receive isolation exceeds 60dB and is limited by the precision of the on-chip balancing impedance. An optimization algorithm finds the optimal duplexer tuning condition in less than...
Unmanned aerial vehicles (UAVs) can be used as aerial base stations (BSs) to deliver broadband wireless connectivity during temporary events, at hotspot areas, or after disasters that may destroy existing communication infrastructure. Since UAV- BSs are low power nodes, their efficient placement is important to reap the maximum capacity and coverage benefits from their deployments. By making use of...
This paper investigates the problem of the interference among multiple simultaneous transmissions in the downlink channel of a multi- antenna wireless system. A symbol-level precoding scheme is considered, where the data information is used, along with the channel state information, in order to exploit the multi-user interference and transform it into useful power at the receiver side. In this framework,...
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