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IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY 2025年 6卷 912-926页

作者： Abu Zaid, Abdullah Belmekki, Baha Eddine Youcef Alouini, Mohamed-Slim King Abdullah Univ Sci & Technol Thuwal 23955 Saudi Arabia Heriot Watt Univ Sch Engn & Phys Sci Edinburgh EH14 4AS Scotland

Urban air mobility (UAM) is increasingly capturing the attention of researchers and industry experts, as it holds the promise of providing faster and more economical solutions for urban commuting. Ensuring reliable communication for UAM aircraft is of paramount importance in maintaining operational safety. To that end, we use stochastic geometry tools to analyze the joint uplink-downlink coverage probability of an integrated aerial-terrestrial heterogeneous network (HetNet) for UAM aircraft, specifically electric vertical takeoff and landing (eVTOL) vehicles. We assume eVTOLs travel on predefined air corridors which are modeled as a Poisson line process (PLP). Furthermore, we model the spatial distribution of eVTOLs as a Matern hardcore process (MHCP) with a designated safety distance. We model the aerial base stations (ABSs) as a two-dimensional (2D) binomial point process (BPP), and the terrestrial base stations (TBSs) as a 2D Poisson point process (PPP). We use a suitable air-to-ground channel model to include line-of-sight (LOS) and non-line-of-sight (NLOS) transmissions. In the paper, we derive distance distributions to the closest ABS, LOS TBS, and NLOS TBS to a typical eVTOL, then we provide the association probability of each BS. Furthermore, we characterize the uplink interference and derive Laplace transforms for the PLP-MHCP distributed eVTOLs. Finally, we derive the coverage probability of the overall HetNet and carry out Monte Carlo simulations to validate our expressions.

关键词： Atmospheric modeling Uplink Downlink Interference Safety Stochastic processes Heterogeneous networks Geometry Two-dimensional displays Three-dimensional displays stochastic geometry coverage probability urban air mobility aerial platforms poisson point process poisson line process matern hardcore process

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Comparisons of various estimates of the I² statistic for quantifying between-study heterogeneity in meta-analysis

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STATISTICAL METHODS IN MEDICAL RESEARCH 2024年第5期33卷 745-764页

作者： Wang, Yipeng DelRocco, Natalie Lin, Lifeng Univ Florida Dept Biostat Gainesville FL USA Univ Southern Calif Dept Populat & Publ Hlth Sci Div Biostat Los Angeles CA USA Univ Arizona Mel & Enid Zuckerman Coll Publ Hlth Dept Epidemiol & Biostat Tucson AZ USA Univ Florida Dept Biostat 2004 Mowry Rd Gainesville FL 32603 USA Univ Arizona Mel & Enid Zuckerman Coll Publ Hlth Dept Epidemiol & Biostat 1295 N MartinAve Tucson AZ 85724 USA

Assessing heterogeneity between studies is a critical step in determining whether studies can be combined and whether the synthesized results are reliable. The I-2 statistic has been a popular measure for quantifying heterogeneity, but its usage has been challenged from various perspectives in recent years. In particular, it should not be considered an absolute measure of heterogeneity, and it could be subject to large uncertainties. As such, when using I-2 to interpret the extent of heterogeneity, it is essential to account for its interval estimate. Various point and interval estimators exist for I-2. This article summarizes these estimators. In addition, we performed a simulation study under different scenarios to investigate preferable point and interval estimates of I-2. We found that the Sidik-Jonkman method gave precise point estimates for I-2 when the between-study variance was large, while in other cases, the DerSimonian-Laird method was suggested to estimate I-2. When the effect measure was the mean difference or the standardized mean difference, the Q-profile method, the Biggerstaff-Jackson method, or the Jackson method was suggested to calculate the interval estimate for I-2 due to reasonable interval length and more reliable coverage probabilities than various alternatives. For the same reason, the Kulinskaya-Dollinger method was recommended to calculate the interval estimate for I-2 when the effect measure was the log odds ratio.

关键词： Confidence interval coverage probability heterogeneity I-2 statistic meta-analysis

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Modeling of Dense CSMA Networks Using Random Sequential Adsorption Process

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2023年第1期72卷 1377-1382页

作者： Parida, Priyabrata Dhillon, Harpreet S. S. Virginia Tech Dept ECE WirelessVT Blacksburg VA 24061 USA

We model a dense wireless local area network (WLAN) where the access points (APs) employ carrier sense multiple access (CSMA)-type medium access control (MAC) protocol. In our model, the spatial locations of the set of active APs are modeled using the random sequential adsorption (RSA) process, which is more accurate in terms of the density of active APs compared to the Matern hard-core point process of type-II (MHPP-II) commonly used for modeling CSMA networks. Leveraging the theory of the RSA process from the statistical physics literature, we provide an approximate but accurate analytical result for the medium access probability (MAP) of the typical AP in the network. Further, we present a numerical approach to determine the pair correlation function (PCF), which is useful for accurate estimation of the interference statistics. Using the PCF result, we derive the signal-to-interference-plus-noise ratio (SINR) coverage probability of the typical link in the network. We validate the accuracy of the theoretical results through extensive Monte Carlo simulations.

关键词： Multiaccess communication Wireless LAN Interference probability Physics Media Access Protocol Measurement coverage probability CSMA medium access probability random sequential adsorption stochastic geometry

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Performance of the NOMA user in FFR Millimeter Wave Networks

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INTERNATIONAL JOURNAL OF ELECTRONICS 2023年第12期111卷 2106页

作者： Lam, Sinh Cong Tran, Xuan Nam Univ Engn & Technol Fac Elect & Telecomunicat VNU H Hanoi Vietnam Le Quy Don Tech Univ Adv Wireless Commun Grp Hanoi Vietnam Univ Engn & Technol Fac Elect & Telecomunicat VNU H E3 Bldg144 Xuan Thuy St Hanoi 11310 Vietnam

Non-Orthogonal Multiple Access (NOMA) and Fractional Frequency Reuse (FFR) were touted as two key techniques of the millimetre wave cellular system to derive spectrum efficiency and user performance improvement. By combining the NOMA and FFR techniques, this paper proposes a system to improve the performance of the NOMA user that utilises the NOMA-power domain technique to reuse an occupied Resource Block (RB). Besides following the power allocation policy of the NOMA technique, the resource allocation algorithm for the NOMA user is based on the FFR technique. Particularly, if the downlink Signal-to-Interference-plus-Noise ratio (SINR) of the NOMA user is greater than the threshold, it is allocated the Cell-Edge RB with a high interference level. Otherwise, it is served on the Cell-Center RB with a low interference level. The analytical and simulation results state that the proposed system can increase the coverage probability of the NOMA user up to 250%.

关键词： Non-Orthogonal multiple Access Fractional frequency reuse ultra dense network Nakagami-m coverage probability

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A new confidence interval for standardized generalized variances of k-multivariate normal populations

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COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION 2023年第10期52卷 5014-5023页

作者： Shahzadi, Asifa Ilyas, Maryam Univ Punjab Coll Stat & Actuarial Sci Lahore 54590 Pakistan

In this article, we have proposed a new confidence interval for the product of standardized generalized variance for k-multivariate normal populations. The results are reported in terms of coverage probabilities and average lengths by designing a simulation study. The performance of the proposed confidence interval is evaluated by comparing it to those provided by Najarzadeh. The results are acceptable. In order to exploit the usefulness of the proposed confidence interval, real life data applications are discussed.

关键词： Average length Confidence interval (CI) coverage probability Simulation method Standardized generalized variance

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Space-Air-Ground-Sea Integrated Networks: Modeling and coverage Analysis

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2023年第9期22卷 6298-6313页

作者： Xu, Jiajie Kishk, Mustafa A. Alouini, Mohamed-Slim King Abdullah Univ Sci & Technol Comp Elect & Math Sci & Engn Div Thuwal 239556900 Saudi Arabia Maynooth Univ Dept Elect Engn Maynooth W23 F2H6 Kildare Ireland

Due to its potential to enable global connectivity in remote locations, such as rural areas and islands, Space-Air-Ground networks have become an ambitious solution for terrestrial communication in the sixth generation (6G) wireless communication network. In this paper, we propose a novel structure of Space-Air-Ground-Sea integrated networks (SAGSINs) to study and derive the coverage probability (CP) of users who are annotated as surface stations (SSs) on the far-reaching ocean surface that is far away from the coastline. By incorporating different types of relays such as onshore stations (OSs), tethered balloons (TBs), high altitude platforms (HAPs), and satellites (SATs), communication links between the terrestrial core connected base stations (CCBSs) and SSs are established via one of the four types of relay stations. Considering practical scenarios with a random distribution of SSs, we model the channel using the point-to-area model, which is recommended by ITU (for OSs to SS), the Rician model (for TBs or HAPs to SS), and the Shadowed-Rician model (for SATs to SS). When the SS's distance from the coastline continues to increase from zero, since different channel models are considered, different relay stations will result in specific received signal strengths at SSs. The most powerful relay station will be chosen as the relay at one time. Hence, as we move away from the coastline, the respective strengths of the different types of relay stations vary, and hence, the association preference (among HAPs, OSs, TBs, and SATs) of the SSs changes leading to a CP value high enough even at locations far away from the coastline into the ocean. We analyze the CP using tools from stochastic geometry. Comparisons of CP between the integrated system with four types of relay stations and the single relay station system (only one type of relay station available) are represented. Numerical results verified by Monte-Carlo simulations reveal insights into the applicability of SAGS

关键词： Space-air-ground-sea integrated networks maritime communication stochastic geometry coverage probability

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Performance Analysis and Optimization of Worst Case User in CoMP Ultra Dense Networks

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IEICE TRANSACTIONS ON COMMUNICATIONS 2023年第10期E106B卷 979-986页

作者： Lam, Sinh Cong VNU Univ Engn & Technol Hanoi Vietnam

In the cellular system, the Worst Case User (WCU), whose distances to three nearest BSs are the similar, usually achieves the lowest performance. Improving user performance, especially the WCU, is a big problem for both network designers and operators. This paper works on the WCU in terms of coverage probability analysis by the stochastic geometry tool and data rate optimization with the transmission power constraint by the reinforcement learning technique under the Stretched Pathloss Model (SPLM). In analysis, only fast fading from the WCU to the serving Base Stations (BSs) is taken into the analysis to derive the lower bound coverage probability. Furthermore, the paper assumes that the Coordinated Multi-Point (CoMP) technique is only employed for the WCU to enhance its downlink signal and avoid the explosion of Intercell Interference (ICI). Through the analysis and simulation, the paper states that to improve the WCU performance under bad wireless environments, an increase in transmission power can be a possible solution. However, in good environments, the deployment of advanced techniques such as Joint Transmission (JT), Joint Scheduling (JS), and reinforcement learning is an suitable solution.

关键词： worst case user point poisson process coverage probability joint transmission reinforcement learning deep Q-learning

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Monitoring reproduction in fish: Assessing the adequacy of ogives and the predicted uncertainty of their L50 estimates for more reliable biological inferences

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FISHERIES RESEARCH 2024年 269卷

作者： Mainguy, Julien Belanger, Martin Ouellet-Cauchon, Genevieve Moral, Rafael de Andrade Minist Environm Lutte Changements Climat Faune & P Direct Expertise Faune Aquat 880 Chem St Foy Quebec City PQ G1S 4X4 Canada Minist Environm Lutte Changements Climat Faune & P Direct Gest Faune Abitibi Temiscamingue 70 Ave Quebec Rouyn Noranda PQ J9X 6R1 Canada Maynooth Univ Dept Math & Stat Maynooth W23 F2H6 Ireland

In fisheries management, the L-50 is a commonly-monitored reproductive trait reflecting the sex-specific length (L) at which 50% of the fish are expected to exhibit developing gonads near the spawning period. Although different methods exist to estimate the L-50, it is often obtained from a binomial generalized linear model (GLM) fitted with a logit link. To provide reliable parameter estimates for the production of the ogive from which the L-50 is obtained, the logit link must be correctly specified, a prerequisite that is not always verified nor true. To identify the most-likely ogive, adequacy tests allowing to detect a lack-of-fit or any link misspecification should ideally be applied to competing binomial models that also consider alternative links, such as the probit and complementary log-log (cloglog). Because multiple estimates are often compared, their uncertainties should also be adequately quantified to detect any potential change, but no consensus exists about the method offering the best coverage probability. Here, we used a large-scale dataset of 23,681 walleye (Sander vitreus) females sampled in 90 harvested populations over two decades in Que' bec, Canada, to first estimate the L-50 uncertainty under different simulation scenarios to identify the most accurate method regarding nominal coverage. Then, of 46 populations sampled in two different surveys, we assessed which link provided the best adequate estimation for each survey-specific L-50 and used associated 84% CIs to determine if a change occurred based on whether they overlapped. The influence of gonad data characteristics on L-50 uncertainty was also examined before assessing between-survey L-50 variation with competing GLMs as an alternative approach. The analysis of the simulated data indicated that the Monte Carlo approach with bias-corrected and accelerated (BCa) interval offered the best coverage probability. The empirical analyses revealed that the probit was the most often adequate link

关键词： Binomial model adequacy coverage probability Ogive Information -theoretic approach Statistical assessment of L- 50 variation

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End-to-End Uplink Performance Analysis of Satellite-Based IoT Networks: A Stochastic Geometry Approach

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY

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IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY 2024年 5卷 4036-4045页

作者： Zhou, Jiusi Wang, Ruibo Shihada, Basem Alouini, Mohamed-Slim King Abdullah Univ Sci & Technol Comp Elect & Math Sci & Engn Div Thuwal 23955 Saudi Arabia

With the deployment of satellite constellations, Internet-of-Things (IoT) devices in remote areas have gained access to low-cost network connectivity. In this paper, we investigate the performance of IoT devices connecting in up-link through low Earth orbit (LEO) satellites to geosynchronous equatorial orbit (GEO) links. We model the dynamic LEO satellite constellation using the stochastic geometry method and provide an analysis of end-to-end availability with low-complexity and coverage performance estimates for the mentioned link. Based on the analytical expressions derived in this research, we make a sound investigation on the impact of constellation configuration, transmission power, and the relative positions of IoT devices and GEO satellites on end-to-end performance.

关键词： Satellites Internet of Things Low earth orbit satellites Fading channels Relays Analytical models Satellite constellations Satellite-based IoT network coverage probability availability probability stochastic geometry

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Reliability in Post-Disaster Networks: A Novel Interference-Mitigation Strategy

IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY

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IEEE OPEN JOURNAL OF VEHICULAR TECHNOLOGY 2024年 5卷 219-229页

作者： Matracia, Maurilio Kishk, Mustafa A. Alouini, Mohamed-Slim King Abdullah Univ Sci & Technol Comp Elect & Math Sci & Engn Div Thuwal 23955 Saudi Arabia Maynooth Univ Elect Engn Dept Maynooth W23 F2H6 Ireland

We hereby present a novel interference mitigation strategy specifically designed to enhance the quality of service that a typical terrestrial user equipment (UE) would experience after the occurrence of a calamity. In particular, we devise a novel stochastic geometry framework where the functioning ground base stations are modeled as an inhomogeneous Poisson point process, and promote proper silencing as an effective solution to improve both coverage and reliability (which is usually overlooked in emergency scenarios);in particular, the latter is evaluated by means of the signal-to-interference-plus-noise ratio (SINR) meta distribution performance metric. The derived downlink performances assume Rayleigh fading conditions for all wireless links. The numerical results show insightful trends in terms of both average coverage probability (which is optimized by choosing the best area for applying the silencing strategy) and SINR meta distribution, depending on: distance of the UE from the disaster epicenter (henceforth intended as the center of the area where the BS can be damaged), disaster radius (also referring to the latter area), and quality of resilience of the terrestrial network. The aim of this paper is therefore to prove the effectiveness of proper silencing in emergency scenarios, at least from the coverage and reliability perspectives.

关键词： Silencing SINR meta distribution coverage probability stochastic geometry post-disaster communications

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