This paper investigates the communication performance of a sleeve dipole antenna used in the Rashid rover, part of the Emirates Lunar Mission, at a frequency of 2.42 GHz. The proposed antenna serves as the primary antenna in the Rashid rover, and its communication performance is evaluated through various scenarios using a simulated model. Initially, a stand-alone antenna was designed, and the results showed that the sleeve dipole antenna provides an omnidirectional radiation pattern and reasonable gain at 2.42 GHz. Subsequently, the model was developed using a simplified model of the lunar ground surface in which the performance of the antenna was evaluated. Finally, the antenna's performance was illustrated in the context of its location, which is close to the metallic mast of the rover which substantially affects antenna parameters. It was also observed that although the electrical properties of the lunar regolith had no significant effect on crucial antenna parameters such as operating frequency and bandwidth; placing the antenna closer to the lunar regolith causes modification in the pattern which results in a moderate increase in gain.

This research investigates the modeling of path loss exponent in an indoor environment at sub-Terahertz (THz) frequencies. The study examines directional and omnidirectional propagation characteristics within an indoor environment at 245 GHz, considering line-of-sight (LOS) and Non-LOS (NLOS) scenarios. Simulations were conducted using the Wireless InSite (WI) software, employing the shoot and bouncing rays (SBR) technique. The received signal strength (RSS) and path loss (PL) recorded during these simulations were comparatively validated against results from the WinProp software, utilizing the dominant path model (DPM). The findings demonstrate a strong agreement between the two techniques.

This paper presents investigations on propagation within an indoor environment based on extensive simulations; the study was based on simulations conducted using Ray-tracing software at 39 GHz. The study considers some of the directional and omnidirectional channel characteristics, including path loss exponent (PLE), delay spread (DS), the number of ray clusters, and the number of rays per cluster in both line-of-sight (LOS) and Non-LOS (NLOS) propagation scenarios. It was found that PLE and DS are frequency-dependent. Also, the number of clusters tends to follow a Poisson distribution, while LOS tends to follow a decaying exponential distribution.

Human activity recognition from sensor data is a critical research topic to achieve remote health monitoring and ambient-assisted living (AAL). In AAL, sensors are integrated into conventional objects aimed to support targets capabilities through digital environments that are sensitive, responsive, and adaptive to human activities. Emerging technological paradigms to support AAL within the home or community setting offers people the prospect of a more individually focused care and improved quality of living. In the present work, an ambient human activity classification framework that augments information from the received signal strength indicator (RSSI) of passive RFID tags to obtain detailed activity profiling is proposed. Key indices of position, orientation, mobility, and degree of activities which are critical to guide reliable clinical management decisions using four volunteers are employed to simulate the research objective. A two-layer, fully connected sequence long short-term memory recurrent neural network model (LSTM RNN) is employed. The LSTM RNN model extracts the feature of RSS from the sensor data and classifies the sampled activities using SoftMax. The performance of the LSTM model is evaluated for different data size and the hyperparameters of the RNN are adjusted to optimal states, which results in an accuracy of 98.18%. The proposed framework suits well for smart health and smart homes which offers a pervasive sensing environment for the elderly, persons with disability and chronic illness.

This paper investigates the optimal number of antennas at a base station, in contrast to what has been accepted in the past: that increasing the number of antennas at base station always enhances performance. In this study, we show that increasing the number of antennas does not always improve the desired performance. Additionally, such increase in antennas consumes more power in transmission and adds to the computation complexity, which in turn needs more time and is more difficult to implement. The optimum number of antennas has been evaluated using simulations. The simulation results show that the optimal ratio equals to 1.2 times the number of active users in each time frame.

This paper presents a low complexity antenna array direction of arrival (DOA) for localization applications in dense environments where GPS localization performance becomes unreliable or unavailable. Thus, a new-efficient angle of arrival (AOA) method called minimum variance noise (MVN) is proposed. The MVN method is based on minimizing the output noise variance of an antenna array; the Lagrange optimization technique is utilized to obtain the optimum weights. Then, the new AOA method is integrated with Orthogonal Frequency Division Multiplexing (OFDM) scheme to improve the estimation accuracy. The produced scheme is combined with a compact-size omnidirectional conical normal mode helical antenna array for supporting the front end model. University of Brad-ford campus is modeled and used as a testbed to evaluate the performance estimation of the proposed localization system. The experiment results are presented and discussed.

Angle of arrival (AOA) estimation plays an essential role in several signal processing applications including tracking systems, beamforming technology and radar systems. An efficient AOA algorithm is proposed to find the direction of multiple arrival signal sources in 2D and 3D applications. The new method is called Minimum Variance Noise (MVN) and it depends upon the minimizing the output noise variance of an antenna array. The main idea and principal working of the MVN algorithm are presented and the mathematical model is derived. The Lagrange optimization technique is utilized to obtain the optimum weights. A computer simulation is carried out on linear and circular arrays including a wide range of scenarios to evaluate the estimation accuracy of the new algorithm. It is also compared with the popular AOA techniques and the results show that it gives better results with lower complexity.

In this paper, a stochastic method is proposed to assess the amount of active and reactive power that can be injected/absorbed to/from grid within a distribution market environment. Also, the impact of wind power penetration on the reactive and active distribution-locational marginal prices is investigated. Market-based active and reactive optimal power flow is used to maximize the social welfare considering uncertainties related to wind speed and load demand. The uncertainties are modeled by Scenario-based approach. The proposed model is examined with 16-bus UK generic distribution system.

The growing synergy between engineering applications and medical science has resulted in the development of effective health care services and applications responsible for higher quality of living for the world's elderly. The growing numbers of elderly demands more efficient system to monitor patients, especially those with degenerative and chronic diseases constrained to indoor healthcare environments. However, effective monitoring requires constant detection of patients' physical position and orientation, as a large proportion of in-hospital accidental deaths result from delays in responding to the physical needs of frail and elderly patients. In this paper, we propose an unobtrusive hybridized indoor approach using passive RFID sensors, biological pressure sensors, low-resolution infrared detectors and triboelectric motion detectors. The proposed system uses a two-level intelligent framework of location and orientation estimation, providing an efficient and prompt response in any emergency while giving the patients freedom to move around within their healthcare environment.

Addressing key management in mobile multicast communication is currently a booming topic due to the convergence of wireless and mobile technologies. With the proliferation of multiple group based services that are possible to co-exist within a single network, mobile subscribers could subscribe to these services concurrently while ubiquitous. However, the existing group key management (GKM) protocols intend to secure group communication for just a single group service. The GKM approaches involve inefficient use of keys and huge rekeying overheads, hence unsuitable for multiple multicast group environments. In this paper, we propose a novel GKM protocol for multiple multicast groups, called slot based multiple group key management (SMGKM) scheme. SMGKM supports the movement of single and multiple members across a homogeneous or heterogeneous wireless network while participating in multiple group services with minimized rekeying transmission overheads. Unlike conventional GKM protocols, SMGKM protocol can mitigate one-affect-n phenomenon, single point of failure and investment pressure of signaling load caused by rekeying at the core network. Numerical analysis and simulation results of the proposed protocol show significant resource economy in terms of communication bandwidth overhead, storage overheads at the Domain Key Distributor (DKD), mobile receiver and Area Key Distributors while providing intense security.

Mobile multicast is recently becoming a hot research in the convergence of wireless and mobile technologies. With the emergence of various multicast-based services, multiple multicast groups are possible to exist within a single network, and mobile subscribers could subscribe to multiple groups concurrently. However, the existing group key management (GKM) protocols intend to secure group communication for just a single group service. The GKM approaches involve inefficient use of keys and huge rekeying overheads, hence unsuitable for multiple multicast group environments. In this paper, we propose a novel GKM protocol for multiple multicast groups, called slot based multiple group key management (SMGKM) scheme. SMGKM supports the movement of single and multiple members across a homogeneous or heterogeneous wireless network while participating in multiple group services with minimized rekeying transmission overheads. Unlike conventional GKM protocols, SMGKM protocol mitigates 1-affect-n phenomenon, single point of failure and investment pressure of signaling load at the core network. The results of the proposed protocol show resource economy in terms of communication bandwidth and storage overheads.

Significant improvements in the quality and reliability of indoor WLAN communications are claimed for devices with MIMO technology applying 802.11n standards, that allow users to achieve a theoretical data rate up to 300-600 Mbps on a single transmission. This paper presents an analysis of a commercial 802.11n MIMO 2×3 dual band (2.4 and 5 GHz) system focusing on the operational throughput performance over an indoor environment for Line of Sight (LOS) and Non Line of Sight (NLOS) scenarios. Efforts on combined field strength distribution, throughput, propagation-channel environments, of this system will be elucidated. The work is focusing on the operational performance of the physical measurements and results compared with simulation model over an indoor environment.