Increase In Communication Range Research Articles

Study on mixed traffic of autonomous vehicles and human-driven vehicles with different cyber interaction approaches

The emergence of autonomous vehicles will significantly improve traffic efficiency and safety. Before the fully autonomous driving of traffic system, the mixed traffic with autonomous and human-driven vehicles will be a typical feature for the future road traffic. To study the properties of a mixed traffic mode combining autonomous and human-driven vehicles, a cellular automata model based traffic system considering autonomous and human-driven vehicles is proposed. In the mixed traffic model, human-driven vehicles can use multiple preceding vehicles' information within drivers' visual range for vehicle motion. For autonomous vehicles, the interaction mechanism of information is iterative and the communication range for vehicle-to-vehicle is considered. The results from this study show that the average traffic flow can be enhanced with the increase of communication range for autonomous vehicles. But when the communication range is big enough, its role on traffic flow is little. Also, it is found that human-driven vehicles' behavior of obtaining multiple preceding vehicles' information can significantly impact the meta-stable state of traffic flow in the average flow density phase. Further, the relationship between the average flow and vehicle density of the mixed traffic flow with random distribution, uniform distribution and separate distribution is discussed. And it reveals that the traffic capacity of the mixed traffic flow with separate distribution is more impressive comparing to the traffic capacity with random distribution and uniform distribution. Finally, the traffic congestion rate under different values of penetration rate is verified and it uncovers that the congestion rate is reduced with the increase of penetration rate.

Dynamic-Detection-Based Trajectory Planning for Autonomous Underwater Vehicle to Collect Data From Underwater Sensors

Marine science and Internet of Underwater Things applications rely significantly on collecting data from underwater sensors. Data collection using long-distance underwater acoustic communications consumes a lot of energy in underwater sensor nodes, which are powered by batteries. To achieve low-energy consumption, we can use the autonomous underwater vehicle (AUV) to move close to sensor nodes and exploit the short-range and high-rate communications. Most of the existing AUV-based data collection schemes consider the scenarios having the knowledge of node positions, where the cruising trajectory can be computed before the AUV’s departure. These schemes cannot apply to some scenarios such as turtle tracking for a certain sea area having no position information. To this end, we first propose a planning-while-detecting approach to dynamically detect the sensors on turtles and adjust the AUV cruising direction to collect data. To further improve data efficiency under the energy limit of the AUV, we group the sensors that can share the same trajectory using their detected directions. A grouping-based dynamic trajectory planning (GDTP) is then proposed to determine the next cruising direction that can visit the group of sensors having the largest amount of data and demanding the least cruising energy at the risk of detection errors. Simulation results show that GDTP achieves significantly higher data collection efficiency than the existing trajectory planning algorithms in dynamic scenarios, and as the communication range increases, it can even outperform the existing algorithms with node locations.

Impacts of vehicle-to-infrastructure communication on traffic flows with mixed connected vehicles and human-driven vehicles

This paper explored the impacts of vehicle-to-infrastructure (V2I) communication on the mixed traffic flow consisting of connected vehicles (CVs) and human-driven vehicles (HVs). We developed a cellular automaton model for mixed flow at the signalized intersection. In addition to considering the motion characteristics of CVs and the influence of HVs on the motion behavior of CVs, the model also considered the influence of signal lights. CVs determine their velocities via V2I communication in order to pass the signal light with less delay and avoid stopping. Through simulations, we found that the presence, frequency and range of V2I communication all make a difference in the mixed flow. Also, 1-Hz communication reduces the number of vehicles within 300 m before the red light from 36 to 26, and the 10-Hz communication reduces one more; 1-Hz communication increases the number of accelerations, but when the frequency increases to 10 Hz, the number of accelerations decreases to the same value as without V2I communication, but the value of number of accelerations increases monotonously with the frequency; traffic delay decreases and capacity increases as the frequency increases. However, as the communication range increases, except that the number of accelerations first decreases and then increases, other traffic characteristics remain unchanged. The number of accelerations reaches a minimum at about 500 m.

Single Sideband Hartley Amplitude Modulation

It is developed a method of information transmission with application of amplitude Single Sideband Hartley modulation (SSBH) allowing to increase of radio channel length for optical and fiber optic signal transmission systems where single sideband amplitude modulation (SSB) is used. Increase of communication range is provided due to application a sum of two orthogonal oscillations of the same frequency as a carrier (Hartley wave). It provides energy gain in 6 dB and 1.41 times increase of the amplitude of output signal of synchronous detector comparing to SSB in case of the same radiation power of transmitter and the same sensitivities of SSBH and SSB signals receivers. Application of SSBH and SSB modulation allows to provide the energy gain in transmitting channel approximately 15–20 times comparing to amplitude modulation (AM) application. It also provides increased security of SSBH transmission since in case of absence of modulation signal the transmitter does not radiate, that allows to provide energy saving in case of transmitter power supply with battery. Depending on the need we can use both upper and lower side bands.

Predictive geographic multicast routing protocol in flying ad hoc networks

In the past decades, the unmanned aerial systems have been utilized only for military operations. However, recently, the potential uses and applicability of unmanned aerial vehicles (commonly known as drones) in civilian application domains are becoming a fast-growing phenomenon. A flying ad hoc network is a wireless ad hoc network specifically designed for the communication of unmanned aerial vehicles. Multicast routing is one of the vital aspects in wireless ad hoc networks. Using multicast transmission approaches, flying ad hoc network applications may need to send the same message to a specific group of flying nodes. The multicast communication approaches can benefit flying ad hoc network applications in conserving the scarce resources of flying nodes. Research works have been proposed to tackle the challenges in multicast routing with multi-hop communication in ad hoc network environments. Nevertheless, the conventional multicast routing mechanisms incur excessive control message overhead when a large number of nodes experience frequent topological changes. A scalable geographic multicast routing mechanism, which specially require localized operation and reduced control packet overhead, is necessary. Multicast routing in flying ad hoc networks is extremely challenging because of the dynamic topology changes and network disconnection resulted from frequent mobility of nodes. In this article, we present and implement a scalable and predictive geographic multicast routing mechanism in flying ad hoc networks. In uniform and random deployment scenarios, the MATLAB-based evaluation result has revealed that when the communication range increases, the probability of finding one-hop predicted forwarders to reach multicast destinations also increases. The implementation of scalable and predictive geographic multicast routing mechanism in flying ad hoc network is done using Optimizing Network Engineering Tools Modeler 16.0. We have added the scalable and predictive geographic multicast routing mechanism in flying ad hoc network as a new routing scheme in the Mobile Ad hoc Network routing protocol groups of the Optimizing Network Engineering Tools Modeler. Then, the performance of scalable and predictive geographic multicast routing mechanism in flying ad hoc network is compared with two of the existing Mobile Ad hoc Network routing protocols (Geographic Routing Protocol and Dynamic Source Routing). Eventually, we present two instance scenarios regarding the integration of scalable and predictive geographic multicast routing mechanism in flying ad hoc network scheme in the Internet of Things platform.

Long-Range and Broadband Aerial Communication Using Directional Antennas (ACDA): Design and Implementation

In this paper, we design and implement a long-range and broadband aerial communication system using directional antennas (ACDA). The system integrates Wi-Fi devices with aerial networks to quickly establish a Wi-Fi infrastructure in the air, which provides real-time communication capability for disasters where a fixed communication infrastructure does not exist. ACDA utilizes unmanned aerial vehicle (UAV)-carried directional antennas to extend communication range, increase throughput, and reduce interference. A GPS-based control algorithm is designed and implemented to automatically reject wind disturbance and align the directions of antennas in accordance with UAV movement. A received signal strength indicator-based decentralized initial scan algorithm is also designed and implemented to quickly establish initial connection between the UAVs. Simulation studies verify the effectiveness of the heading control and initial scan algorithm. Field tests are also conducted to evaluate the performance of overall system in terms of throughput and delay with respect to the increase of communication range. The ACDA prototype system achieves 48 Mb/s throughput at a distance of 300 m and 2 Mb/s at 5000 m, and proves the promising usage of directional antennas for long-distance Wi-Fi aerial communication. Practical use of this on-demand communication system to aid emergency response is also demonstrated through a case study in a real disaster drill.

Effect of information availability on stability of traffic flow: Percolation theory approach

Connectivity and automation are expected to enhance safety and efficiency in transportation systems. Connectivity will provide information to drivers/autonomous vehicles to enhance decision-making reliability at the operational and tactical levels. Consequently, drivers are more likely to execute safe and efficient maneuvers and autonomous vehicles will have a more accurate perception of the traffic condition and an “error-free” execution of the driving maneuvers. At the operational level, ensuring string stability is a key consideration since unstable traffic flow results in shockwave propagation and possibly crashes. While several studies have examined the effects of information availability on string stability in a connected environment, most of the approaches are focused on automated driving (e.g., Cooperative Adaptive Cruise Control systems) and do not consider a mixed environment with regular, connected, and autonomous vehicles. To ensure connectivity in such a mixed environment, the correlation between communication range and connected vehicles density should be considered. To capture the effects of this correlation, this study uses the Continuum Percolation theory to determine the effects of the vehicular density and communication range on the connectivity level in telecommunications network and consequently, on the string stability of traffic flow. Based on the Continuum Percolation theory, there is a critical density of connected vehicles above which the entire system is connected. This critical density also depends on the communication range. This study presents an analytical derivation of this critical density. Moreover, this study evaluates the string stability under different communication ranges and market penetration rates of connected and autonomous vehicles. Results revealed that as communication range increases, the system becomes more stable and at high communication ranges, the system performs similar to the system with full connectivity. Moreover, results indicated the existence of an optimal communication range to maximize stability and ensure information delivery.

Effect of Information Availability on Stability of Traffic Flow: Percolation Theory Approach

Abstract: Connectivity and automation are expected to enhance safety and efficiency in transportation systems. Connectivity will provide information to drivers/autonomous vehicles to enhance decision-making reliability at the operational and tactical levels. Consequently, drivers are more likely to execute safe and efficient maneuvers and autonomous vehicles will have a more accurate perception of the traffic condition and an “error-free” execution of the driving maneuvers. At the operational level, ensuring string stability is a key consideration since unstable traffic flow results in shockwave propagation and possibly crashes. While several studies have examined the effects of information availability on string stability in a connected environment, most of the approaches are focused on automated driving (e.g., Cooperative Adaptive Cruise Control systems) and do not consider a mixed environment with regular, connected, and autonomous vehicles. To ensure connectivity in such a mixed environment, the correlation between communication range and connected vehicles density should be considered. To capture the effects of this correlation, this study uses the Continuum Percolation theory to determine the effects of the vehicular density and communication range on the connectivity level in telecommunications network and consequently, on the string stability of traffic flow. Based on the Continuum Percolation theory, there is a critical density of connected vehicles above which the entire system is connected. This critical density also depends on the communication range. This study presents an analytical derivation of this critical density. Moreover, this study evaluates the string stability under different communication ranges and market penetration rates of connected and autonomous vehicles. Results revealed that as communication range increases, the system becomes more stable and at high communication ranges, the system performs similar to the system with full connectivity. Moreover, results indicated the existence of an optimal communication range to maximize stability and ensure information delivery.

A SERVEY ON WIRELESS MESH NETWORKING MODULE

There is a rapid development in sensor devices as well as increase in communication range with various low power wireless radio transmitter and receiver using wireless mesh network. Wireless mesh networking is useful to collect the information from different sensors that are widely distributed over a large area. In this survey, we mainly focus on open source module that is shown by various authors. For this purpose many authors use Zigbee module for the development of sensor systems with capability of mesh networking. In this survey, we mainly focus on wireless mesh networking, for that we studied different wireless sensors to transmit and receive the data from them and can monitor the output at regular interval on our screen. WSN consist of different sensors that are distributed with the capabilities of computing, processing and communication can continuouslysense the data in terms of packets and transmit that data at regular interval. They design such model in which integrates the various functions such as type of network, data routing and scheduled of transmission data. Also design wireless mesh network structure for various monitoring application such as industrial, agricultural, medical and so many with a good average packet delivery ratio upto 93%. This proposed system has the advantage of low cost combined with high reliable information of transmitter without complications of wireless mesh networking. And finally we conclude from that study of WMN, the range of communication can be increased by Using Pro-Zigbee module (up to 1.6Km) as well as we can monitor that, if one of the node is fail to transmit a data ,then their data will automatically stored in neighboring node as backup.

Connectivity Reestablishment in Self-Organizing Sensor Networks with Dumb Nodes

In this work, we propose a scheme, named CoRAD , for the reestablishment of lost connectivity using sensor nodes with adjustable communication range in stationary wireless sensor networks (WSNs), when “dumb” behavior occurs some of the nodes. Due to the occurrence of such behavior, there may be temporary loss of connectivity between among the nodes. Such a phenomenon is different from the commonly known node isolation problem in stationary WSNs. The mere activation of intermediate sleep nodes cannot guarantee reestablishment of connectivity, because there may not exist neighbor nodes of the isolated nodes. On the contrary, the increase in communication range of a single sensor node may make it die quickly. Including this, a sensor node has maximum limit of increase in communication range that may not be sufficient to reestablish connectivity. Therefore, considering all these factors for self-organization of the network and isolated node re-connection, we propose a price-based scheme, which addresses the issue by activating intermediate sleep nodes or by adjusting the communication range of some of the other nodes in the network. The scheme also deactivates the additional activated nodes and reduces the increased communication range when the dumb nodes resume their normal behavior, upon the return of favorable environmental conditions. To implement the proposed scheme, CoRAD it is required to construct the network using GPS-enabled adjustable communication range sensor nodes. Through simulation we compare our proposed scheme with the existing topology management schemes -- LETC and A1 -- in the same scenario by considering the number of activated nodes, message overhead, and energy consumption. We find that the proposed scheme shows improved performance compared to the existing topology management schemes.

Non-line-of-sight ultraviolet communication performance in atmospheric turbulence

Non-Line-of-Sight (NLOS) Ultraviolet (UV) communication uses the atmosphere as a propagation medium. As the communication range increases, turbulence becomes a significant atmospheric process that affects the propagation of optical waves. This paper presents a more accurate NLOS channel model by considering turbulence-induced Scintillation Attenuation (SA). Then, the Bit Error Rate (BER) during turbulence of the NLOS UV communication system with On-Off Keying (OOK) modulation and Maximum Likelihood (ML) detection is analysed and compared with that in free space without turbulence. The BER dependence is also analysed for different factors, including the refractive index structure parameter, transceiver range, pointing angles, transmitted power, and data rate.

Low modulation index RF signal detection for a passive UHF RFID transponder

In a typical RFID system the reader transmits modulated RF power to provide both data and energy for the passive transponder. Low modulation index RF energy is preferable for an adequate tag power supply and increase in communication range but gives rise to difficulties for near-field conventional demodulation. Therefore, a novel ASK demodulator for minimum 20% modulation index RF signal detection over a range of 23 dB is presented. Thanks to the proposed innovative divisional linear conversion from the power into voltage signal, the detection sensitivity is ensured over a wide power range with low power consumption of 8.6 μW. The chip is implemented in UMC 0.18 μm mix-mode CMOS technology, and the chip area is 0.06 mm2.

RFID 시스템의 통신 거리 증대를 위한 전파흡수체 개발

본 논문에서는 RFID Tag가 금속판에 접근할 때 통신 거리가 감소되는 RFID 시스템의 통신 거리 증대를 위한 전파흡수체를 개발하였다. 먼저 자성 손실 재료인 Amorphous 금속 분말과 지지재인 CPE(Chlorinated Polyethylene)를 이용하여 조성비별 전파흡수체 샘플을 제작하고, 이 전파흡수체 샘플로부터 구한 재료정수를 이용하여 전파흡수능이 서로 다른 전파흡수체를 각각 설계 제작하였다. 이와 더불어 개발된 전파흡수체를 적용하여 금속에 의해 특성이 열화되는 RFID 태그 안테나의 특성 개선 효과 및 실제 RFID 시스템의 통신 거리 변화를 실험적으로 검토하였다. 그 결과 조성비가 Amorphous metal powder:CPE=80:20 wt.%이고, 두께가 4 mm인 전파흡수체가 금속판으로 인해 통신 거리가 0.8 m인 실제 RFID 시스템의 통신 거리를 5.2 m까지 증대시킴을 확인하였다. In this paper, we designed and fabricated the EM wave absorbers for preventing the reduction of the communication range when RFID Tag is approached to a metal plate. The EM wave absorber samples were fabricated with difference composition ratios of Amorphous metal powder and CPE, the absorption abilities of which were simulated by substituting different thicknesses of the EM wave absorbers. Then the EM wave absorbers are manufactured based on the simulated results. By using the EM wave absorbers, we have confirmed the improvement effect of RFID tag antenna and the increase of communication range of RFID system. As a result, it was cleary shown that the communication range of RFID system is improved by adopting the EM wave absorber with the composition ratio of Amorphous metal powder:CPE=80:20 wt.% and the thickness of 4 mm. Thus, it was confirmed that the proposed EM wave absorber can increase the communication range of RFID system from 0.8 m to 5.2 m in UHF band.

Fault tolerant multiple event detection in a wireless sensor network

With an increasing acceptance of Wireless Sensor Networks (WSNs), the health of individual sensor is becoming critical in identifying important events in the region of interest. One of the key challenges in detecting event in a WSN is how to detect it accurately transmitting minimum information providing sufficient details about the event. At the same time, it is also important to devise a strategy to handle multiple events occurring simultaneously. In this paper, we propose a Polynomial-based scheme that addresses these problems of Event Region Detection (PERD) by having a aggregation tree of sensor nodes. We employ a data aggregation scheme, TREG (proposed in our earlier work) to perform function approximation of the event using a multivariate polynomial regression. Only coefficients of the polynomial ( P ) are passed instead of aggregated data. PERD includes two components: event recognition and event report with boundary detection. This can be performed for multiple simultaneously occurring events. We also identify faulty sensor(s) using the aggregation tree. Performing further mathematical operations on the calculated P can identify the maximum (max) and minimum (min) values of the sensed attribute and their locations. Therefore, if any sensor reports a data value outside the [min, max] range, it can be identified as a faulty sensor. Since PERD is implemented over a polynomial tree on a WSN in a distributed manner, it is easily scalable and computation overhead is marginal. Results reveal that event(s) can be detected by PERD with error in detection remaining almost constant achieving a percentage error within a threshold of 10 % with increase in communication range. Results also show that a faulty sensor can be detected with an average accuracy of 94 % and it increases with increase in node density.