Wireless Channel Research Articles

Implantable Medical Device Security

Implantable medical devices, or IMDs for short, are medical instruments that are placed into the human body through surgery. IMDs are typically used for treating chronic diseases. Currently available IMDs are capable of communicating using wireless channels with other devices, either in close proximity or even connected to the Internet, making IMDs part of the Internet of Medical Things. This capability opens the possibility of developing a wide range of services, like remote patient data control, localization in case of emergency, or telemedicine, which can improve patients’ lifestyle. On the other hand, given the limited resources of such tiny devices, and the access to the Internet, there are numerous security issues to be considered when designing and deploying IMDs and their support infrastructures. In this paper, we highlight security problems related to Internet-connected IMDs, and survey some solutions that have been presented in the literature.

Method for determining the effect of destabilizing factors of digital filters on the multicriteria synthesis of radio communications of aviation robotic devices

The purpose of the research is development of a method for determining the influence of destabilizing factors, such as the unevenness of the amplitude-frequency response (AFC) and the nonlinearity of the phase-frequency response (FFC), in non-recursive digital frequency selection filters on the target function of multicriteria structural-parametric synthesis of radio communications from the payload of aviation robotic devices.Methods. In conducting scientific research, probability theory, mathematical statistics, statistical radio engineering and computational mathematics were used. The study obtained mathematical expressions of the dependence of the probability of error per bit (BER) on the average signal-to-noise ratio when signals pass through symmetrical non-recursive digital filters with quadrature amplitude modulation with a positivity of no more than 4096, signal constellation irregularities of no more than 5, which are the basis for the energy balance of radio lines with aviation robotic devices. The expressions obtained are one of the "foundations" for the implementation of a multi-criteria synthesis of radio systems adaptive to a cognitively formed flight task. In this paper, all the results of the probability of reliability of the received data by means of communication are reflected for the case of rigid decision-making (Gray coding).Results. In the course of the conducted research: 1) a mathematical model of the structural-parametric synthesis of radio communications with aviation robotic devices is demonstrated, which is based on the criteria for minimizing: electronic computing resources with a given noise immunity; radiation outside the operating frequency band; peak factor signals; the effects of narrowband, broadband and structural interference in the radio channel at a given bandwidth; the use of structural and functional nodes specific to the existing information and communication environment; 2) the analytical dependence of the influence of the parameters of one of several structural and functional nodes - digital filters of frequency selection, on the criteria for the synthesis of communication means has been revealed. The paper considers the most common approximating functions - Kaiser, Tukey, Barlett-Khan, Chebyshev, and also shows the influence of the filter order on the equivalent of energy loss in information communication lines of aviation robotic devices.Conclusion. The scientific article presents a method for determining the effect of the uneven frequency response of a symmetrical non-recursive digital filter in devices for receiving and processing radio signals of multicriteria means of communication with the payload of aviation robotic devices. The proposed approach increases the reliability of determining the values of criteria for minimizing electronic computing resources for a given noise immunity, radiation outside the operating frequency band, as well as the use of structural and functional nodes characteristic of the existing information and communication environment.

Real-time full-duplex transmission experiment for an air and underwater invisible light communication system

Specifications for highly secure and large-capacity optical transceivers are necessary when wireless communication is used over different transmission channels, such as underwater and air, in shallow sea areas. We evaluated the dynamic characteristics of bidirectional real-time transmission using an LED Backhaul that can generate and process direct current-added orthogonal frequency division multiplexing signals in the 850 nm band to demonstrate the feasibility of invisibility light communication. A composite channel that is 1.2 m in water and 10 m in the air was used as an optical radio channel. This experiment is the first report on real-time and 4 K video stream transmission for a line-of-sight full-duplex optical wireless communication in the invisible light band via heterogeneous transmission channels such as shallow water and air.

A Novel Approach for Improving XML Querying over Wireless Broadcast Channels

The querying of large XML data over wireless broadcast channels can reduce bandwidth utilization, cause significant latency, and produce inefficient energy usage. This paper proposes a scheme to improve XML querying over wireless broadcast channels in order to address the issues mentioned above. Various techniques, including partitioning, load balancing, and query routing, have been combined into one approach. The proposed scheme partitions the XML data stream into several partitions based on criteria like document size, type, or content. Each partition is routed to a separate channel to balance the load on each wireless broadcast channel. A query routing mechanism that directs queries to the right channel or combination of channels that hold the relevant XML data partition was implemented. This study simulates, evaluates, and compares the proposed scheme’s performance. The results from the comparison study with existing schemes demonstrate a considerable reduction in the access time for XML querying via wireless broadcast channels.

ASSESSMENT OF SMALL HOLDERS FARMERS' ADOPTION OF CLIMATE-SMART AGRICULTURE PRACTICES IN BORNO STATE, NIGERIA

The study assessed smallholder farmers’ adoption of Climate-Smart Agriculture practices in Borno State, Nigeria. Identified socio-economic characteristics of the respondents, assessed the respondents’ adoption of climate-smart agriculture practices and investigated the constraint by respondents in adopting climate-smart agriculture practices. Both primary and secondary sources were used. Multi-stage sampling procedure was employed to select 200 respondents as the sample size. Descriptive statistics such as frequency, percentages, mean, standard deviation and likert type scale were used. The findings indicated that, majority (67.5%) of the respondents were within the prime working age of 20-49 years with a mean age of 43 years. Majority (75.5%) were male, 63.5% married with 43.0% had 7-9 persons per household. However, more than half (56%) of the respondents had no formal education, and 56% earn less than 50,000 Naira annually. The study also found that 58% had more than 10 years of farming experience, but only 30% were members of association. Conservation agriculture practices such as reduced tillage, crop residue management, and crop rotation/intercropping were rated 1st with the highest (x = 4.29) implying strong agreement to adoption of conservation agriculture practices. The climate smart agricultural practices highly adopted by the respondents include; water retention and erosion control technique (89%) and efficient fertilizer application technique (79.5%), moderately adopted practices; home garden (63%) and compost making/green manuring (58%), whereas least adopted practices; early warning system (20.0%) and use of more efficient cooking stove (17%). The most severe constraint identified include lack of awareness and limited information about climate smart agriculture practices (x=1.87), as well as limited access to credit (x=1.80). High cost of labor for climate smart agriculture and policy inconsistencies (x=1.32, 1.44) were identified as not severe constraint compared to others. The study recommended that Extension agents and Research institute should create more awareness on impact of adopting Climate Smart Agriculture (CSA) practices and improve easy accessibility to weather and climate information through provision of mobile-based platforms or community radio broadcasts that deliver timely and relevant information.

Exploiting EEG to identify confused students in online learning: A machine learning model comparison

Abstract. The COVID-19 pandemic has forced most schools, including universities, to adopt online courses for teaching. Due to the breaking of the constraints of time and space, online courses still occupy a large proportion in education until now, and large-scale open online education courses will become a major trend in the future. Of course, problems also arise in this process. As teachers cannot receive feedback from students anytime and anywhere in online courses, such as micro expressions, body movements, etc., they cannot know whether students are confused. Therefore, how to effectively detect students' learning status has grown in popularity. In the last few years, machine learning has developed rapidly, and a large number of artificial intelligence have emerged, making it possible to detect whether students are confused by combining electroencephalography with machine learning. In order to determine whether students were confused, this study used a wireless single channel Mindset device to collect Electroencephalography (EEG) signals. Six machine learning modelsrandom forests, eXtreme Gradient boosting, K-nearest neighbors, gradient boosting machines, logistic regression, and support vector machineswere then chosen. The findings indicate that other machine learning models have a high accuracy rate in classifying students' bewilderment, with the exception of the logistic regression model. With a 99.69% accuracy rate, the eXtreme gradient boosting model performs better than a number of other models.

Clipper: Online Joint Client Sampling and Power Allocation for Wireless Federated Learning

Communication overhead is a main bottleneck in federated learning (FL) especially in the wireless environment due to the limited data rate and unstable radio channels. The communication challenge necessitates holistic selection of participating clients that accounts for both the computation needs and communication cost, as well as judicious allocation of the limited transmission resource. Meanwhile, the random unpredictable nature of both the training data samples and the communication channels requires an online optimization approach that adapts to the changing system state over time. In this work, we consider a general framework of online joint client sampling and power allocation for wireless FL under time-varying communication channels. We formulate it as a stochastic network optimization problem that admits a Lyapunov-typed solution approach. This leads to per-training-round subproblems with a special bi-convex structure, which we leverage to propose globally optimal solutions, culminating in a meta algorithm that provides strong performance guarantees. We further study three specific FL problems covering multiple scenarios, namely with IID or non-IID data, whether robustness against data drift is required, and with unbiased or biased client sampling. We derive detailed algorithms for each of these problems. Simulation with standard classification tasks demonstrate that the proposed communication-aware algorithms outperform their counterparts under a wide range of learning and communication scenarios.

The Method of Measuring the Occupancy of the Radio Frequency Spectrum, Varying According to the Daily Cycle

Relevance. Management of the use of the radio frequency spectrum requires taking into account the actual occupancy of radio channels and frequency bands. However, the patterns of occupancy change underlying the International Telecommunication Union (ITU-R) Radiocommunication Sector documents do not fully meet the needs of practice. Some of the ITU-R recommendations are focused on estimating local occupancy for short time intervals; other recommendations involve measurements in stationary radio channels, although only a small part of real radio channels can be counted on to have the constant occupancy throughout the time axis. At the same time, the activities of many organizations, and therefore the resources they use, are subject to a daily cycle of activity, which allows us to recommend for consideration a model of occupancy change in accordance with the daily cycle. The aim of the work is to develop a methodology for collecting information and forming an estimate of the daily occupancy change for the analyzed radio channels. Methods used. The development of recommendations for the collection of data for occupancy monitoring is based on the practical approaches of radio monitoring services and classical methods of statistical analysis. Novelty. In this paper, a new model for changing the occupancy of radio frequency channels in accordance with the daily cycle is proposed for use, as well as a statistically justified method for measuring occupancy.Result. The proposed methodology allows us to obtain a practically oriented assessment of occupancy changes, which does not require replacing the fleet of equipment traditionally used by radio monitoring services; the necessary changes can be implemented with relatively simple software modification. The paper provides preliminary recommendations for ensuring the accuracy and reliability of measurements, based on a traditionally used mathematical apparatus, which involves limiting the relative measurement error. This entails the need for very long measurements for the most important low-occupied radio channels. So, it is necessary to look for alternative measurement accuracy requirements that would meet the real needs of radio monitoring services.Practical significance. The acceptance of the developed methodology will eliminate the currently existing contradiction between the theoretical provisions underlying the ITU recommendations and the practice of conducting radio-controlled measurements.

Race and Privacy in Broadcast Police Communications

Radios are essential for the operations of modern police departments, and they function as both a collaborative communication technology and a sociotechnical system. However, little prior research has examined their usage or their connections to individual privacy and the role of race in policing, two growing topics of concern in the US. As a case study, we examine the Chicago Police Department's (CPD's) use of broadcast police communications (BPC) to coordinate the activity of law enforcement officers (LEOs) in the city. From a recently assembled archive of 80,775 hours of BPC associated with CPD operations, we analyze human-generated text transcripts of radio transmissions broadcast 9:00 AM to 5:00 PM on August 10th, 2018 in one majority Black, one majority White, and one majority Hispanic area of the city (24 hours of audio) to explore four research questions: (1) Do BPC reflect reported racial disparities in policing? (2) How and when is gender, race/ethnicity, and age mentioned in BPC? (3) To what extent do BPC include sensitive information, and who is put at most risk by this practice? (4) To what extent can large language models (LLMs) heighten this risk? We explore the vocabulary and speech acts used by police in BPC, comparing mentions of personal characteristics to local demographics, the personal information shared over BPC, and the privacy concerns that it poses. Analysis indicates (a) policing professionals in the city of Chicago exhibit disproportionate attention to Black members of the public regardless of context, (b) sociodemographic characteristics like gender, race/ethnicity, and age are primarily mentioned in BPC about event information, and (c) disproportionate attention introduces disproportionate privacy risks for Black members of the public. This study shows BPC can provide a novel window into disproportionate attention (i.e., via radio communications) by law enforcement officers to specific racial groups, leading to increased privacy vulnerability for those groups, particularly Black males.

Конструкция split infinitive в английском языке сегодня

The analysis of numerous BBC radio broadcasts in English, of articles in the magazine New Scientist and different research papers shows that the last two-to-three years have seen a dramatic increase in the use of split infinitives in unprepared oral speech by people of different backgrounds and nationalities. Most common are split infinitives with adverbs. The author concludes that if the current trend in the increased use of split infinitives continues, the structure can become a part of the recognised language norm and will soon find its way into English grammars and textbooks.

Design and Evaluation of Steganographic Channels in Fifth-Generation New Radio

Mobile communication is ubiquitous in everyday life. The fifth generation of mobile networks (5G) introduced 5G New Radio as a radio access technology that meets current bandwidth, quality, and application requirements. Network steganographic channels that hide secret message transfers in an innocent carrier communication are a particular threat in mobile communications as these channels are often used for malware, ransomware, and data leakage. We systematically analyze the protocol stack of the 5G–air interface for its susceptibility to network steganography, addressing both storage and timing channels. To ensure large coverage, we apply hiding patterns that collect the essential ideas used to create steganographic channels. Based on the results of this analysis, we design and implement a network covert storage channel, exploiting reserved bits in the header of the Packet Data Convergence Protocol (PDCP). the covert sender and receiver are located in a 5G base station and mobile device, respectively. Furthermore, we sketch a timing channel based on a recent overshadowing attack. We evaluate our steganographic storage channel both in simulation and real-world experiments with respect to steganographic bandwidth, robustness, and stealthiness. Moreover, we discuss countermeasures. Our implementation demonstrates the feasibility of a covert channel in 5G New Radio and the possibility of achieving large steganographic bandwidth for broadband transmissions. We also demonstrate that the detection of the channel by a network analyzer is possible, limiting its scope to application scenarios where operators are unaware or ignorant of this threat.

Comparative Analysis of the Signal Strength of Two Radio Stations in Okene, Kogi State, Nigeria

There are significant concerns for the citizens of Okene and its surroundings; regarding the distortions experienced in radio signals due to increased attenuation, which have resulted in poor signal quality. This study carried out a comparative analysis of the signal strength of two radio broadcast stations in Okene, Kogi State, Nigeria, using a field strength meter. The study involved measuring the signal strength for each radio stations at six selected locations in Okene and surrounding area. The wavelength and free space path-loss was calculated at sixteen different locations. The results indicated an inverse relationship between the measured signal strengths and the path-loss, as well as the approximate distance amid antennas. The transmitting signal strength was 100.9dBµV (KA) and 102.2dBµV (KB). Distance from station where signal can be receive was 72.0km (KA) and 69.0km (KB). The free space path loss experienced was 109.01dB (KA) and 109.39dB (KB). Even though KA has a lower transmitting signal strength, its longer wavelength 3.21m and lower frequency 93.5MHz gives it an age over KB with higher frequency 109.5MHz and shorter wavelength 2.94m. However, it is recommended that the FM stations should strategically enhance their network infrastructure to improve service delivery, particularly where performance lags. Booster stations at approximately 69km away from the main stations can effectively enhance the signal, leading to better signal quality and improved customer satisfaction.

Composite underwater optical wireless channel modeling based on the electric field Monte Carlo method

In this study, we propose a simulation method to investigate the scattering characteristics of beams with specific phase structures in waters containing micrometer-scale particles and bubbles. This method is based on the electric field Monte Carlo (EMC) algorithm and utilizes the Mie theory and ray tracing method. We simulate the propagation of orbital angular momentum (OAM) beams in a composite underwater channel using the proposed method and analyze the impact of bubble density on the spiral phase distribution of the OAM beams. We also design an underwater experiment in a water tank to simulate the propagation of OAM beams in the composite channel. The results reveal that the power of the desired mode of the OAM beam decreases as the bubble density increases, which is consistent with the simulation results. This method facilitates a realistic simulation of structured light beam propagation in waters containing particles and bubbles and can provide reference data for studying the scattering characteristics of structured beams in composite underwater channels.

Awareness and Usage of Artificial Intelligence (AI) in Promoting Music Broadcast on Radio in Warri, Nigeria

This paper investigates the level of awareness and usage of artificial intelligence (AI) for promoting music broadcast on radio stations in Warri, Nigeria. The study was prompted by the paradigm shift that is brought about by the advent of artificial intelligence. Despite the advantages inherent in technology most radio stations appear to lack knowledge of the component meant for the broadcast of music. Thus, the study establishes the extent to which the radio station in Warri, Nigeria has become AI compliant in relaying music. To determine the AI awareness level and extent of usage in music promotion on radio stations, the researcher conducted interview sessions using four (4) radio stations, forty-one (41) on Air Personalities (OAP). A Self Respondent Interview Research Instrument was administered via email contact. The study was guided by three (3) research questions. Data were analyzed with the aid of percentage calculation measure to decide the level of awareness and usage of the AI tools connected to music broadcast on radio. The study found that respondents show low level of awareness of significant AI tools and thus could not deploy AI technologies for broadcast of music. The study concludes that it is important to create high level of awareness in the use of AI tools for promotion of music broadcast on radio. The study recommends that OAP should acquire the knowledge of AI tools related to promotion of music on radio stations. The proprietors of radio stations should provide training on the use of AI technologies to enable them become AI compliant in radio broadcasting.

Feasibility of Sexual Health and Contraceptive Web Services for Adolescents and Young Adults: Retrospective Study of a Pilot Program on Reunion Island.

Sexual health indicators for adolescents and young adults (AYAs) aged between 13 and 25 years are particularly poor on Reunion Island. Access to accurate information as well as sexual health and contraceptive services are vital to maintaining sexual well-being. Teleconsultations offer a promising approach to addressing the sexual health and contraceptive needs of AYAs who are more susceptible to engaging in unprotected sexual intercourse. However, the literature on digital sexual health services for this demographic group is limited. This study aims to describe the feasibility of a pilot sexual health and contraceptive teleconsultation web service used by AYAs on Reunion Island. A descriptive, retrospective study was conducted at the Reunion Island University Hospital Center using a convenient sample. Eligible participants were informed about the program through various communication channels, including seminars for health care professionals, radio broadcasts, posters, flyers, press articles, videos, and social media posts. AYAs accessed a web-based platform named SEXTUOZE from December 15, 2021, to September 30, 2022, that offered sexual health information and teleconsultations. Data collected included participant and teleconsultation characteristics, patient satisfaction, and the quality of completeness of medical records. A total of 22 teleconsultations were scheduled and 7 were completed, all via synchronous video communication (duration: median 35 min). Overall, 4731 sessions were generated on the SEXTUOZE website. Reasons cited for accessing the web services were to seek sexual health advice (8/22, 36%), receive an initial birth control prescription (12/22, 55%), and inquire about condom prescriptions (2/22, 9%). While teleconsultation use for sexual health was initially low, it rose toward the end of the study period. Considering all elements of the implementation theory, future research should design interventions that not only are more operative and tailored but also ensure their adoption and sustainability in various health contexts.

Optimized Architecture for Efficient OFDMA Network Design

This study presents a novel approach to enhancing the design and performance of OFDMA (Orthogonal Frequency Division Multiple Access) networks, with a particular focus on WiMAX (Worldwide Interoperability for Microwave Access) for Best Effort (BE) services. The proposed method integrates a robust Markovian analytical model with four advanced scheduling algorithms: throughput fairness, resource fairness, opportunistic scheduling, and throttling. A sophisticated simulator was developed, incorporating an ON/OFF traffic generator, user-specific wireless channels, and a dynamic central scheduler to validate the model’s accuracy and evaluate its robustness by dynamically allocating radio resources per frame. The validation study showed that the proposed model reduced simulation time by over 90%, completing analytical calculations in just 15 min, compared to nearly 2 days for simulations using conventional scheduling algorithms. Performance metrics such as the average number of active users and resource utilization closely matched those from the validation study, confirming the model’s accuracy. In the robustness study, the model consistently performed well across diverse traffic distributions (exponential and Pareto) and channel conditions. The proposed architecture increased network throughput by up to 25% and reduced latency under dynamic conditions, demonstrating its scalability, adaptability, and efficiency as a crucial solution for next-generation wireless communication systems.

Lattice All-Pass Filter Based Precoder Adaptation for MIMO Wireless Channels

Lattice All-Pass Filter Based Precoder Adaptation for MIMO Wireless Channels

Wireless Channel Propagation Model for Inland Waterway Bridge Scenario

Intelligent shipping is a crucial part of the transportation system, while inland river intelligent shipping is a major safeguard of intelligent transportation. Compared with the studies of mobile fading channels in land-based environments, less current research has focused on channel measurements and modeling for inland waterway bridge environments. In this paper, a segmenting radio channel model is proposed for inland highway and railway combined bridges. The ship's path under the bridge was divided into three phases, and the attenuation of signal strength was modelled separately for each. Hence, it shows ship-to-ship wireless channels in different areas and path loss on inland navigation bridges. A segmented model, instead of a basic path loss model, can accurately forecast path loss and provide a practical approach in ship-to-ship wireless channel transmission scenarios over bridges. Consequently, the channel measurements and modeling in the typical inland waterway are of great significance for establishing a reliable inland navigation broadband radio communication system.

Dakwah Media Radio Jakarta Islami Center (JIC) di Era Digital

The development and advancement of today's technological world have helped overcome various obstacles in life. In the digital era, the fulfilment of information needs is a necessity that cannot be denied. Da'wah through radio media radio owned by the DKI Jakarta government is one of the radios that broadcast Islamic da'wah. Radio as a broadcasting media also has a role in its da'wah mission. Like Radio Jakarta Islamic Center by implementing da'wah programs in its broadcast content. It's broadcast content. This writing aims to describe the role of da'wah through JIC radio media in the digital era. Researchers conducted in-depth interviews with interviewing informants including the head of the JIC radio da'wah program, the head of JIC radio, and two JIC radio broadcasters.JIC, and two JIC radio broadcasters. The data analysis technique is carried out by the results showed that the role of JIC radio media da'wah in the digital era is increasingly enhanced following the development of the JIC radio program. The digital era is increasingly being improved by following technological developments and the use of social media such as YouTube and others. Radio JIC uses some creative strategies when there is media convergence to improve the quality of broadcasters and can to improve the quality of broadcasters and can strive for broadcasters to present material well. Keywords: Digital Era, Da'wah, Media Convergence, Radio JIC

A Three-Dimensional Time-Varying Channel Model for THz UAV-Based Dual-Mobility Channels

Unmanned aerial vehicle (UAV) as an aerial base station or relay device is a promising technology to rapidly provide wireless connectivity to ground device. Given UAV’s agility and mobility, ground user’s mobility, a key question is how to analyze and value the performance of UAV-based wireless channel in the terahertz (THz) band. In this paper, a three-dimensional (3D) time-varying channel model is proposed for UAV-based dual-mobility wireless channels based on geometric channel model theory in THz band. In this proposed channel model, the small-scale fading (e.g., scattering fading and reflection fading) on rough surfaces of communication environment and the atmospheric molecule absorption attenuations are considered in THz band. Moreover, the statistical properties of the proposed channel model, including path loss, time autocorrelation function (T-ACF) and Doppler power spectrum density (DPSD), have been derived and the impact of several important UAV-related and vehicle-related parameters have been investigated and compared to millimeter wave (mm-wave) band. Furthermore, the correctness of the proposed channel model has been verified via simulation, and some useful observations are provided for the system design of THz UAV-based dual-mobility wireless communication systems.