The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
S. Kozono - One of the best experts on this subject based on the ideXlab platform.
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A study of received Signal-Level distribution in wideband transmissions in mobile communications
IEEE Transactions on Vehicular Technology, 1999Co-Authors: S. KozonoAbstract:A mobile propagation model, which includes not only indirect arriving waves but also a direct arriving waves and is applicable to picocell, microcell, and macrocell, is proposed in order to clarify fundamental propagation characteristics in instantaneous received Signal-Level variation through narrowband and wideband transmissions. On the basis of this model, we derive a mathematical expression for the instantaneous received Signal-Level. Through an analysis of this expression, a new propagation parameter called equivalent received bandwidth 2/spl Delta/f/spl Delta/L/sub max/ is proposed. The dependence of the received Signal-Level distribution on the new parameter is studied by computer simulation. It is shown that the fading depth depends strongly on the 2/spl Delta/f/spl Delta/L/sub max/, as a parameter of the power ratio a. When 2/spl Delta/f/spl Delta/L/sub max/10 MHz/spl middot/m, the fading depth depends not only on the power ratio a but also on the 2/spl Delta/f/spl Delta/L/sub max/ and it decreases as 2/spl Delta/f/spl Delta/L/sub max/ increases. On the other hand, the number of arriving waves and the minimum effective amplitude of arriving waves are examined quantitatively. According to the results, when the number of arriving waves N is larger than 6, the fading depth is independent of N, and the minimum amplitude of arriving waves should be larger than -20 dB relative to the maximum amplitude in indirect arriving waves.
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Received Signal-Level, characteristics of wide-band transmission in mobile communications
Proceedings of PIMRC '96 - 7th International Symposium on Personal Indoor and Mobile Communications, 1996Co-Authors: S. Kozono, S. Seino, H. NakabayashiAbstract:In mobile communications, the received Signal Level of a wide-band transmission differs from that of a narrow-band transmission. Only a few studies have been done to clarify the received Signal-Level characteristics of a wide-band transmission. In order to normalize the Signal-Level distribution we propose a new propagation parameter called the equivalent received bandwidth 2/spl Delta/f/spl Delta/L/sub max/ which is a product of the received bandwidth 2/spl Delta/f and the maximum difference in the propagation path length /spl Delta/L/sub max/. We evaluated the relation between this new propagation parameter and the fading depth by computer simulation, and we found they are closely related. Further, we have examined the received Signal-Level autocorrelation dependence on the received bandwidth and difference in path length, theoretically and by computer simulation. The result showed that the autocorrelation was independent of both.
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Received Signal-Level characteristics in a wide-band mobile radio channel
IEEE Transactions on Vehicular Technology, 1994Co-Authors: S. KozonoAbstract:A mobile propagation model aimed at clarifying fundamental propagation characteristics in received Signal-Level variation for wide-band transmission is proposed. On the basis of this model, the author derives an expression for a received Signal Level in wide-band transmission and examines the fundamental Signal-Level characteristics by computer simulation and experiment. Both simulation and measurement results agree well and the results follow. For a received Signal-Level variation in wide-band transmission: first, received Signal-Level depth becomes shallower with increasing receiver bandwidth 2/spl Delta/f, and the Level has no Rayleigh distribution. In an urban area when 2/spl Delta/f is 3 MHz, the Level difference between the cumulative probability 50% and 1% values is about 5 dB. Second, received Signal-Level distribution depends on the number of arriving waves N and path length difference |/spl Delta/L/sub ij/|. The Level depth becomes shallower with increasing N and |/spl Delta/L/sub ij/|. Third, received Signal-Level distribution is almost independent of radio frequency f/sub c/. The author also derives expressions for the autocorrelation coefficient /spl rho/(z) and frequency coefficient /spl rho/(s) of the received Signal Level. /spl rho/(z) is independent of 2/spl Delta/f, and is about J/sub 0/(Z//spl lambda//sub c/)/sup 2/, which is known as narrow-band reception. The /spl rho/(s) becomes higher with increasing 2/spl Delta/f.
Roberto Verdone - One of the best experts on this subject based on the ideXlab platform.
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partial compensation Signal Level based up link power control to extend terminal battery duration
IEEE Transactions on Vehicular Technology, 2001Co-Authors: Marco Chiani, Andrea Conti, Roberto VerdoneAbstract:Power control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the Signal-Level (not on cochannel interference) show good characteristics in terms of network stability and provide optimum downlink performance when a half-compensation scheme is used instead of a full-compensation algorithm. This work is concerned with partial (including the full and half cases) compensation Signal-Level-based PC algorithms and their impact on battery duration of mobile terminals, i.e., the uplink is investigated. A time division multiple access (TDMA)-based cellular system is considered. The effect of a slow PC, i.e., following only slow channel fluctuations, on the average transmitted power of mobile terminals is evaluated through a completely analytical model; both ideal and nonideal PC are considered. Starting from suitable requirements on radio coverage, we show that a half-compensation PC scheme is often a good choice for extending terminal battery life (thus, also reducing health risks).
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On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration
Multiaccess Mobility and Teletraffic in Wireless Communications: Volume 4, 1999Co-Authors: Marco Chiani, Andrea Conti, Roberto VerdoneAbstract:Power Control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the Signal Level (not on Cochannel Interference) show good characteristics in terms of network stability and provide optimum downlink performance when a Half Compensation scheme is used instead of a Full Compensation algorithm.
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Signal-Level-based power control over slow frequency hopped mobile radio systems
1999 IEEE 49th Vehicular Technology Conference (Cat. No.99CH36363), 1999Co-Authors: Marco Chiani, Roberto Verdone, A. Conti, A. ZanellaAbstract:We analyze the joint effects of power control (PC) and slow frequency hopping (SFH). We propose a semi-analytical procedure to determine the outage of SFH TDMA-based mobile radio systems with Signal-Level-based power control, both for the up-link and the down-link. In the up-link case the procedure is completely analytical whereas the down-link requires a semi-analytical approach to take users' positions into account. With the aim of showing that the behavior of the systems can be improved by means of suitable choice of the PC parameters, we evaluate the performance of SFH TDMA mobile radio systems in terms of service coverage.
Marco Chiani - One of the best experts on this subject based on the ideXlab platform.
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partial compensation Signal Level based up link power control to extend terminal battery duration
IEEE Transactions on Vehicular Technology, 2001Co-Authors: Marco Chiani, Andrea Conti, Roberto VerdoneAbstract:Power control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the Signal-Level (not on cochannel interference) show good characteristics in terms of network stability and provide optimum downlink performance when a half-compensation scheme is used instead of a full-compensation algorithm. This work is concerned with partial (including the full and half cases) compensation Signal-Level-based PC algorithms and their impact on battery duration of mobile terminals, i.e., the uplink is investigated. A time division multiple access (TDMA)-based cellular system is considered. The effect of a slow PC, i.e., following only slow channel fluctuations, on the average transmitted power of mobile terminals is evaluated through a completely analytical model; both ideal and nonideal PC are considered. Starting from suitable requirements on radio coverage, we show that a half-compensation PC scheme is often a good choice for extending terminal battery life (thus, also reducing health risks).
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On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration
Multiaccess Mobility and Teletraffic in Wireless Communications: Volume 4, 1999Co-Authors: Marco Chiani, Andrea Conti, Roberto VerdoneAbstract:Power Control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the Signal Level (not on Cochannel Interference) show good characteristics in terms of network stability and provide optimum downlink performance when a Half Compensation scheme is used instead of a Full Compensation algorithm.
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Signal-Level-based power control over slow frequency hopped mobile radio systems
1999 IEEE 49th Vehicular Technology Conference (Cat. No.99CH36363), 1999Co-Authors: Marco Chiani, Roberto Verdone, A. Conti, A. ZanellaAbstract:We analyze the joint effects of power control (PC) and slow frequency hopping (SFH). We propose a semi-analytical procedure to determine the outage of SFH TDMA-based mobile radio systems with Signal-Level-based power control, both for the up-link and the down-link. In the up-link case the procedure is completely analytical whereas the down-link requires a semi-analytical approach to take users' positions into account. With the aim of showing that the behavior of the systems can be improved by means of suitable choice of the PC parameters, we evaluate the performance of SFH TDMA mobile radio systems in terms of service coverage.
Mohamed-slim Alouini - One of the best experts on this subject based on the ideXlab platform.
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Hybrid Scheduling/Signal-Level Coordination in the
2020Co-Authors: Ahmed Douik, Hayssam Dahrouj, Tareq Y. Al-naffouri, Mohamed-slim Alouini, Abdullah, FahdAbstract:In the context of resource allocation in cloud-radio access networks, recent studies assume either Signal-Level or scheduling-Level coordination. This paper, instead, considers a hybrid Level of coordination for the scheduling problem in the downlink of a multi-cloud radio-access network, so as to benefit from both scheduling policies. Consider a multi-cloud radio access network, where each cloud is connected to several base- stations (BSs) via high capacity links, and therefore allows joint Signal processing between them. Across the multiple clouds, however, only scheduling-Level coordination is permitted, as it requires a lower Level of backhaul communication. The frame structure of every BS is composed of various time/frequency blocks, called power-zones (PZs), and kept at fixed power Level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled, at most, to a single cloud, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs' frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The scheduling problem is, then, shown to be equivalent to a maximum-weight independent set problem in the constructed graph, in which each vertex symbolizes an association of cloud, user, BS and PZ, with a weight representing the utility of that association. Simulation results suggest that the proposed hybrid scheduling strategy provides appreciable gain as compared to the scheduling-Level coordinated networks, with a negligible degradation to Signal- Level coordination.
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hybrid scheduling Signal Level coordination in the downlink of multi cloud radio access networks
arXiv: Information Theory, 2015Co-Authors: Ahmed Douik, Hayssam Dahrouj, Tareq Y Alnaffouri, Mohamed-slim AlouiniAbstract:In the context of resource allocation in cloud-radio access networks, recent studies assume either Signal-Level or scheduling-Level coordination. This paper, instead, considers a hybrid Level of coordination for the scheduling problem in the downlink of a multi-cloud radio-access network, as a means to benefit from both scheduling policies. Consider a multi-cloud radio access network, where each cloud is connected to several base-stations (BSs) via high capacity links, and therefore allows joint Signal processing between them. Across the multiple clouds, however, only scheduling-Level coordination is permitted, as it requires a lower Level of backhaul communication. The frame structure of every BS is composed of various time/frequency blocks, called power-zones (PZs), and kept at fixed power Level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled, at most, to a single cloud, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs' frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The scheduling problem is, then, shown to be equivalent to a maximum-weight independent set problem in the constructed graph, in which each vertex symbolizes an association of cloud, user, BS and PZ, with a weight representing the utility of that association. Simulation results suggest that the proposed hybrid scheduling strategy provides appreciable gain as compared to the scheduling-Level coordinated networks, with a negligible degradation to Signal-Level coordination.
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Hybrid Scheduling/Signal-Level Coordination in the Downlink of Multi-Cloud Radio-Access Networks
2015 IEEE Global Communications Conference (GLOBECOM), 2015Co-Authors: Ahmed Douik, Hayssam Dahrouj, Tareq Y. Al-naffouri, Mohamed-slim AlouiniAbstract:In the context of resource allocation in cloud- radio access networks, recent studies assume either Signal-Level or scheduling-Level coordination. This paper, instead, considers a hybrid Level of coordination for the scheduling problem in the downlink of a multi-cloud radio- access network, so as to benefit from both scheduling policies. Consider a multi-cloud radio access network, where each cloud is connected to several base-stations (BSs) via high capacity links, and therefore allows joint Signal processing between them. Across the multiple clouds, however, only scheduling-Level coordination is permitted, as it requires a lower Level of backhaul communication. The frame structure of every BS is composed of various time/frequency blocks, called power- zones (PZs), and kept at fixed power Level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled, at most, to a single cloud, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs' frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The scheduling problem is, then, shown to be equivalent to a maximum- weight independent set problem in the constructed graph, in which each vertex symbolizes an association of cloud, user, BS and PZ, with a weight representing the utility of that association. Simulation results suggest that the proposed hybrid scheduling strategy provides appreciable gain as compared to the scheduling-Level coordinated networks, with a negligible degradation to Signal-Level coordination.
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hybrid scheduling Signal Level coordination in the downlink of multi cloud radio access networks
Global Communications Conference, 2014Co-Authors: Ahmed Douik, Hayssam Dahrouj, Tareq Y Alnaffouri, Mohamed-slim AlouiniAbstract:In the context of resource allocation in cloud- radio access networks, recent studies assume either Signal-Level or scheduling-Level coordination. This paper, instead, considers a hybrid Level of coordination for the scheduling problem in the downlink of a multi-cloud radio- access network, so as to benefit from both scheduling policies. Consider a multi-cloud radio access network, where each cloud is connected to several base-stations (BSs) via high capacity links, and therefore allows joint Signal processing between them. Across the multiple clouds, however, only scheduling-Level coordination is permitted, as it requires a lower Level of backhaul communication. The frame structure of every BS is composed of various time/frequency blocks, called power- zones (PZs), and kept at fixed power Level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled, at most, to a single cloud, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs' frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The scheduling problem is, then, shown to be equivalent to a maximum- weight independent set problem in the constructed graph, in which each vertex symbolizes an association of cloud, user, BS and PZ, with a weight representing the utility of that association. Simulation results suggest that the proposed hybrid scheduling strategy provides appreciable gain as compared to the scheduling-Level coordinated networks, with a negligible degradation to Signal-Level coordination.
Costas Xydeas - One of the best experts on this subject based on the ideXlab platform.
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objective evaluation of Signal Level image fusion performance
Optical Engineering, 2005Co-Authors: Vladimir Petrovic, Costas XydeasAbstract:An objective measurement framework for Signal-Level image fusion performance, based on a direct comparison of visual information in the fused and input images, is proposed. The aim is to model and predict subjective fusion performance results otherwise obtained through extremely time- and resource-consuming perceptual evaluation proce- dures. The measure associates visual information with edge, or gradient, information that is initially parametrized at all locations of the inputs and the fused image. A perceptual-information preservation model is then used to quantify the success of information fusion as the accuracy with which local gradient information is transferred from the inputs to the fused image. By considering the perceptual importance of different im- age regions, such local fusion success estimates are integrated into a single, numerical fusion performance score between 0 total information loss and 1 ideal fusion. The proposed metric is optimized and vali- dated using extensive subjective test results and validation procedures. The results clearly indicate that the proposed metric is perceptually meaningful in that it corresponds well with the results of perceptual fu- sion evaluation. Finally, an application of the proposed evaluation ap- proach to fusion algorithm selection and fusion parameter optimization demonstrates its general usefulness. © 2005 Society of Photo-Optical Instrumen-
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sensor noise effects on Signal Level image fusion performance
Information Fusion, 2003Co-Authors: Vladimir Petrovic, Costas XydeasAbstract:The aim of this paper is twofold: (i) to define appropriate metrics which measure the effects of input sensor noise on the performance of Signal-Level image fusion systems and (ii) to employ these metrics in a comparative study of the robustness of typical image fusion schemes whose inputs are corrupted with noise. Thus system performance metrics for measuring both absolute and relative degradation in fused image quality are proposed when fusing noisy input modalities. A third metric, which considers fusion of noise patterns, is also developed and used to evaluate the perceptual effect of noise corrupting homogenous image regions (i.e. areas with no salient features). These metrics are employed to compare the performance of different image fusion methodologies and feature selection/information fusion strategies operating under noisy input conditions. Altogether, the performance of seventeen fusion schemes is examined and their robustness to noise considered at various input Signal-to-noise ratio values for three types of sensor noise characteristics.
