Search results for "Downlink"

showing 10 items of 11 documents

Enhanced LMMSE equalizer for high-speed single frequency network in HSDPA

2011

Currently, considerable interest has been shown in the research and standardization communities in multicell transmission schemes for HSPA, with a number of possible schemes under discussion that include Multiflow, Fast Cell Switching (FCS) and High-Speed Single Frequency Network (HS-SFN). In particular, HS-SFN is a promising technique that not only combines received energy from participating cells, but also reduces intercell interference with low UE complexity. In principle, HS-SFN can be implemented with a small modification to an LMMSE receiver at the UE. This paper introduces a more advanced LMMSE equalizer for High-Speed Single Frequency Network in HSDPA that achieves further performan…

EngineeringTransmission (telecommunications)business.industryCellular radioElectronic engineeringEqualizerSingle-frequency networkHigh-Speed Downlink Packet AccessCell relayInterference (wave propagation)businessEnergy (signal processing)2011 IEEE Swedish Communication Technologies Workshop (Swe-CTW)
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Healthy and sustainable diet and physical activity: the rationale for and experiences from developing a combined summary score

2018

Aims: First, to describe the rationale for developing a combined summary score, the Healthy and Sustainable Dietary and Physical Activity habits (HSDPA) score, incorporating four selected dietary and physical activity aspects: (a) the New Nordic Diet, (b) local and sustainable foods, (c) active transportation and (d) non-exercise outdoor activities. Secondly, to describe the experiences from constructing the HSDPA score. Methods: Relevant literature covering the four aspects of interest was reviewed to secure a well-grounded rationale and a theory-based approach. To measure compliance with such a broad approach targeting diet, physical activity, health and environmental sustainability, the…

GerontologyConservation of Natural Resources030505 public healthPublic Health Environmental and Occupational HealthPhysical activityHigh-Speed Downlink Packet AccessGeneral Medicine03 medical and health sciences0302 clinical medicineSustainabilityFeasibility StudiesHealth Status IndicatorsHumans030212 general & internal medicineDiet Healthy0305 other medical sciencePsychologyExerciseScandinavian Journal of Public Health
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Decoupled Downlink-Uplink Coverage Analysis with Interference Management for Enriched Heterogeneous Cellular Networks

2016

Heterogeneous cellular networks (HetCNets) offer a promising solution to cope with the current cellular coverage crunch. Due to the large transmit power disparity, while following maximum power received (MPR) association scheme, a larger number of users are associated with macro-cell BS (MBS) than small-cell BSs (SBSs). Therefore, an imbalance load arrangement takes place across the HetCNets. Hence, using cell range expansion-based cell association, we can balance the load across the congested MBS. However, using MPR association scheme, users’ offloading leads to two challenges: 1) macro-cell interference , in which the MBS interferes with the offloaded users, and 2) coupled downlink-uplink…

Heterogeneous cellular networksGeneral Computer ScienceComputer science02 engineering and technologyInterference (wave propagation)Frequency allocationsmall-cell BSsLoad managementBase stationcoverage performance0203 mechanical engineeringTelecommunications linkreverse frequency allocation0202 electrical engineering electronic engineering information engineeringGeneral Materials Sciencedecoupled downlink-uplink associationbusiness.industryGeneral Engineering020302 automobile design & engineering020206 networking & telecommunicationsTransmitter power outputCellular networklcsh:Electrical engineering. Electronics. Nuclear engineeringbusinesslcsh:TK1-9971Computer networkIEEE Access
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Joint Spectral and Energy Efficiency Optimization for Downlink NOMA Networks

2020

Non-orthogonal multiple access (NOMA) holds the promise to be a key enabler of 5G communication. However, the existing design of NOMA systems must be optimized to achieve maximum rate while using minimum transmit power. To do so, this paper provides a novel technique based on multi-objective optimization to efficiently allocate resources in the multi-user NOMA systems supporting downlink transmission. Specifically, our unique optimization technique jointly improves spectrum and energy efficiency while satisfying the constraints on users quality of services (QoS) requirements, transmit power budget and successive interference cancellation. We first formulate a joint problem for spectrum and …

OptimizationMathematical optimizationComputer Networks and CommunicationsComputer scienceenergiatehokkuus5G-tekniikka02 engineering and technologySilicon carbideMulti-objective optimizationNomalangaton tiedonsiirto0203 mechanical engineeringoptimointiPower system managementQuality of serviceArtificial IntelligenceTelecommunications link0202 electrical engineering electronic engineering information engineeringmedicineSpectral efficiencyDownlinkResource managementNOMA020302 automobile design & engineering020206 networking & telecommunicationsSpectral efficiencyTransmitter power outputmedicine.diseaseMulti-objective optimizationEnergy efficiencySingle antenna interference cancellationHardware and ArchitectureNon-orthogonal multiple accessBenchmark (computing)QoS.Efficient energy use
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Blind source separation based interference suppression schemes for OFDM and DS-CDMA

2015

In statistical wireless signal processing, extraction of unobserved signals from observed mixtures can be achieved using Blind Source Separation (BSS) algorithms. Orthogonal Frequency Division Multiplexing (OFDM) and Direct Sequence-Code Division Multiple Access (DS-CDMA) can be pronounced as the well established predominant air interface communication techniques. Consequences of an effort taken and counteractive solutions to diminish the undesirable influences encountered within the wireless air interface of those techniques with aid of BSS schemes are disclosed. Filter coefficients for the receiver are ascertained with the support of a set of energy functions and the iterative fixed point…

Orthogonal frequency-division multiplexingCode division multiple accessComputer sciencebusiness.industryAir interface0206 medical engineering020206 networking & telecommunications02 engineering and technology020601 biomedical engineeringBlind signal separationdownlinkslow fadingFilter designInterference (communication)blind source separationTelecommunications link0202 electrical engineering electronic engineering information engineeringElectronic engineeringFadingElectrical and Electronic EngineeringTelecommunicationsbusinessDS-CDMAOFDMTelecommunication Systems
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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Luby Transform Performance Tests on Time-Correlated Channel Model for Geo Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniSettore ING-INF/01 - ElettronicaFree Space Optics Luby Transform Codes Rateless Codes Channel Modeling Geo Free Space Optics Downlinks
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VoIP end-to-end performance in HSPA with packet age aided HSDPA scheduling

2008

In this paper, we present an enhanced VoIP scheduling for the high speed downlink packet access (HSDPA) in UMTS, which takes the age of the VoIP packet into account. The downlink capacity can be significantly improved by this way, especially for shorter uplink transmission delay. In order to quantify the achievable performance improvement, we present results obtained from extensive system-level uplink and downlink simulations. Inter alia, it is shown that using the proposed scheme can lead to an increase in the downlink cell capacity of up to 16%. By applying the proposed method, the downlink performance can be improved considerably while the uplink performance remains the same, which ensur…

Voice over IPComputingMethodologies_SIMULATIONANDMODELINGComputer sciencebusiness.industryCode division multiple accessNetwork packetComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKSReal-time computingHigh-Speed Downlink Packet Accessscheduling performance analysisData_CODINGANDINFORMATIONTHEORYScheduling (computing)Channel capacityEnd-to-end principleHSPATelecommunications linkbusinessUMTS frequency bandsComputer network2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications
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On Serving Cell Change Reliability in HSDPA Network

2009

In Wideband Code Division Multiple Access (WCDMA) networks the Signaling Radio Bearer (SRB) is transmitted downlink to inform the user i.a. when it needs to make a handover. When transmitting e.g. Voice over IP (VoIP) on High Speed Downlink Packet Access (HSDPA) SRB is mapped on HSDPA user data channel, High-Speed Downlink Shared Channel (HS-DSCH) in order to maximize voice capacity. The lack of support for soft handover (SHO) of HS-DSCH may compromise the reception of SRB and thus also a possible incoming serving HSDPA cell change command especially at the cell borders. This can lead to serious VoIP service degradation due to prolonged camping on a poor cell and in the worst case even to c…

Voice over IPbusiness.industryComputer scienceNetwork packetCode division multiple accessMacro cellReal-time computingHigh-Speed Downlink Packet AccessSoft handoverSpread spectrumHandoverW-CDMATelecommunications linkbusinessComputer network2009 IEEE Wireless Communications and Networking Conference
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HSDPA Link Adaptation Improvement Based on Node-B CQI Processing

2007

In this paper HSDPA link adaptation (LA) based on Channel Quality Indicator (CQI) reports is optimised. A pre-processing of the last received CQI reports is done before the execution of the LA algorithm in the Node-B in order to obtain more profitable channel quality estimations and hence improve the LA performance. Different types of processing techniques are presented and assessed, considering from the simplest sample averaging to some more elaborated predictive algorithms. Results demonstrate that a non negligible enhancement in the LA performance can be obtained if medium and high speed users are considered.

business.industryComputer sciencemedia_common.quotation_subjectNode (networking)Real-time computingHigh-Speed Downlink Packet AccessSample (statistics)Link adaptationPredictive analyticsQuality (business)Mobile telephonybusinessComputer networkmedia_commonCommunication channel2007 4th International Symposium on Wireless Communication Systems
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