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With the development of various wireless communication networks, Wi-Fi Router positioning and deployment systems have become widely popular in recent years to improve coverage in various environments. In this paper, we present an appropriate mechanism for defining the deployment of Wi-Fi Routers to improve coverage in the Oxford Languages Institute (OLI) environment. In addition, the institute's environment was simulated using the Wireless InSite (WI) Package. In this work, two types of Wi-Fi Routers are used. The first is the TP-Link, while the second is the Rocket. These two devices operate at 2.4 and 5 GHz frequencies. There are two objectives in this work. The first aim is to determine the best location to cover the simulated scene environment in a better way. The second aim is to compare Wi-Fi Routers to find out which Wi-Fi Router is better and find out how many Wi-Fi Routers we need to cover the institute's environment. The comparison between Wi-Fi Routers was based on basic parameters to measure the performance of wireless networks, the most important of which are Coverage Rate (CR) Percentage, Signal Quality Rate (SQR), and Received Power Rate (RPR). According to the results that were shown on the Graphical User Interface (GUI) using MATLAB Software. We noticed that the CR, SQR, and RPR of the Rocket are 83.9080%, 97.0082%, and -35.2337 dBm respectively, and these results are better than the results provided by the TP-Link, as it gave the CR, SQR, and RPR are 32.1839%, 77.8690%, and -58.1685 dBm, respectively. Finally, we conclude that CR using the Rocket is good and we need one device to cover the institute's environment. While CR using the TP-Link is bad and we need five devices to reach the coverage provided by the Rocket because the Rocket has high transmitted power and gain capacity. [ABSTRACT FROM AUTHOR]

Wireless networks are the preferred future access networks for both defense and civilian deployments as part of telecommunication networks. The successful implementation of long term evolution (LTE) networks and applications such as the Internet of Things (IoT) in the telecommunication infrastructure has guaranteed rates of up to 100 Mbps while supporting ultra-dense wireless access network. With the incorporation of LTE-Advanced and fifth-generation wireless protocols, the data rates are expected to reach upto 1 Gbps. Hence, there is a pertinent requirement to carry out channel measurements at sub 1 GHz, 2 GHz, and 3 GHz bands to enable the design and implementation of optimum transceivers for pico-cells of LTE and future wireless networks. For the first time measurements and comparison with standard models of channel impulse response models have also been carried out in five different terrains namely Urban, Semi-Urban, Forest, Rural, and Desert terrains in the Indian sub-continent to effectively cover a variety of deployments of future wireless access networks for defense wireless networks. [ABSTRACT FROM AUTHOR]

The 5th generation (5G), the next generation mobile communication, has more requirements than the previous generation 4th generation (4G). For example, Spectral efficiency, peak data rate and mobility it is. Of these requirements, Orthogonal Time Frequency Space (OTFS) has been proposed as a waveform design study to support mobility. OFDM used in 5G and 4G has a weak point in high speed environment. When the frequency shift occurs due to the Doppler effect, orthogonality between subcarriers of OFDM is broken and performance is degraded. To compensate for this, a complex Doppler compensation algorithm is required, which leads to an increase in complexity. OTFS processes signals in two dimensions in the delay-Doppler domain through the Symplectic Finite Fourier Transform (SFFT). It is compatible with conventional OFDM and can be used as pre-coder and post-coder to effectively handle Doppler without complicative compensation algorithms. This paper evaluates and compares the performance of OFDM and OTFS in high Doppler and time delay environments. As a receiver, we used MP detector proposed for OTFS. The performance is similar to OFDM at low SNR, and the performance is noticeably better than OFDM at high SNR. [ABSTRACT FROM AUTHOR]

Underwater acoustic (UWA) channels are one of the historical mobile ultrawideband channels characterized by large delay and Doppler spreads, but reliable UWA communication remains challenging. Here we performed an initial demonstration of the Doppler-resilient orthogonal signal division multiplexing (D-OSDM) technique in an actual sea environment. D-OSDM spreads data symbols in both time and frequency with guardbands to exploit the time and frequency diversity of UWA channels. The experiment was performed in a challenging scenario: the transmitter was fixed on a floating pier, and the receiver was mounted on a moving remote-controlled boat. The harbor UWA channel had a delay spread of 50 ms and a Doppler spread of up to 4.5 Hz, in the presence of additive Gaussian noise, and the combination of two Rayleigh fading models (a two-path model without Doppler spread and a multi-path model with Doppler spread) was able to successfully model the actual environment. Our results also confirmed that a UWA communication link using D-OSDM will deliver excellent reliability even for a harbor UWA channel with a mobile receiver; D-OSDM achieves better communication quality compared to other communication schemes in both simulations and experiments. [ABSTRACT FROM AUTHOR]

This paper presents millimeter-wave (mmWave) propagation characteristics and channel model parameters including path loss, delay, and angular properties based on 28 GHz and 38 GHz field measurement data. We conducted measurement campaigns in both outdoor and indoor at the best potential hotspots. In particular, the model parameters are compared to sub-6 GHz parameters, and system design issues are considered for mmWave 5G Giga communications. For path loss modeling, we derived parameters for both the close-in free space model and the alpha-beta-gamma model. For multipath models, we extracted delay and angular dispersion characteristics including clustering results. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the wideband propagation characteristic for an indoor multi-floor scenario is investigated based on wideband multi-frequency channel measurements in two typical indoor environments. Based on the measurement results, the log-distance (LD) model is used to analyze path loss (PL) in different floors. We find that the total penetration loss does not increase linearly in dB with the number of floors traversed, and the propagation condition in same floor, that is line of sight (LOS) or non-LOS (NLOS), can affect the penetration loss significantly. Besides, additional loss caused by traversing floor upwards is 1–2 dB larger than that introduced by traversing floor downwards. Then, we adopt a small error-prediction attenuation factor (AF) model for PL prediction. The modeling process and rationality of the AF model are presented. Finally, delay spread of wideband indoor channel is analyzed. Statistics of time dispersion parameters are compared among floors and frequencies. It is found that the delay spread on the middle floors is the largest, the delay spread on higher floors is relatively small due to lack of power source, and its relation with frequency is not obvious. [Copyright &y& Elsevier]

In this paper, a novel approach of using deterministic multipath arrivals is presented to highlight the relationship between the coherence bandwidth and the root mean square time delay spread. This is done via a measurement campaign that sounds the wireless channel using frequency sweep measurements, where the wireless link is purposefully disturbed by the motion of a reflecting surface mounted to a robot arm. That motion is designed to induce deterministic components into the set of multipath arrivals, allowing those components to be isolated from those multipaths that are random. Those isolated deterministic arrivals are then manipulated using signal processing methods to confirm the well known inverse proportionality between the coherence bandwidth and the time delay spread to highlight the efficacy of this novel deterministic multipath approach. As such, it will be shown that the inverse proportionality constant determined in our controlled environment is nearly identical to a theoretical lower bound proposed in the literature. Finally, the use of deterministic paths for improved medium access control level performance is discussed relative to traditional physical layer statistical methods. We argue that the ability to extract deterministic paths in a multipath environment may reduce the amount of signal processing required to study the statistical nature of wireless channels for some applications of interest. [ABSTRACT FROM AUTHOR]

This paper presents a new way to estimate delay spread in machine workspaces by using fractal geometry. In this way, inventories can be created quickly and used within a ray tracing software to estimate the radio environment of machine workspaces as part of the planning process. Delay spread is an important metric in assessing the performance of wireless technologies. Predicted 5G cyber–physical systems in workplaces will require high-density use of wirelessly connected machine-to-machine RF modules. In workshops, the surfaces and edges of machines, shelves, and furniture influence the multipath/power delay profile of the space. However, with the fast construction pace and high occupancy of buildings, it is impractical to characterize the location as building work progresses. Consequently, it becomes more probable that the radio communication system deployed will perform suboptimally. In this work, the Wi-Fi band was investigated. In addition, representative simulations were also carried out at millimetre wave frequencies of 28 GHz and 60 GHz. [ABSTRACT FROM AUTHOR]