Reliable Real-time Communication Research Articles

A Protocol for Reliable Real-Time Wireless Communication of Large Data Samples

In this paper, we present a middleware protocol, that transmits larger-than-a-frame data samples within application real-time and reliability requirements over a lossy wireless channel. The protocol efficiently deploys an intelligent retransmission control that exploits the extended deadline requirements of a sample for frame-level scheduling. The transmission of such samples is placed in the context of the necessary integration of such external sensor data into the decision-making process of an autonomous vehicle. Therefore, we provide parameterization and access rules for communication links in resource-managed scenarios and lay out how to integrate the protocol into the popular DDS middleware. The performance of the parameterized links to satisfy their reliability requirements is studied and compared to error protection protocols in the current software stack. We base the evaluation on an OMNeT++ simulation, whereby an established wireless error model is used. The use case is placed in the context of collaborative sensing in a valet parking environment, where external infrastructure sensor data augments the autonomous vehicle's data processing chain via a lossy wireless link. Thereby, the use case adheres to the underlying safety requirements. Results show that if the protocol's awareness of the application requirements is used for parameterization, guarantees for reliability can be provided that outperform existing solutions.

Troid: A Real-Time Multiplayer FPS Game

Abstract: Troid is a real-time multiplayer first-person shooter (FPS) game designed to be played on a web browser without the need for a high-end PC or dedicated graphics card. The game allows two players to join a room and engage in a fast-paced, action-packed gameplay experience. The purpose of Troid is to provide a high-quality FPS game that can be enjoyed on any device with a modern web browser and an internet connection, regardless of hardware specifications. Unlike most FPS games that require high-end hardware to run smoothly, Troid is optimized for minimal requirements. Troid's front-end is built using a reactive web framework that facilitates the creation of fast and interactive user interfaces, while the game's graphics and animation are created using a 3D graphics library. Real-time communication between players is facilitated using a reliable real-time communication library, and an in-memory data store is utilized to store player coordinates and other in-game data. Overall, Troid exemplifies the potential of creating highquality multiplayer games that can be played on any device with a modern web browser and an internet connection, without compromising on the gameplay experience.

Secure Contact Agreement Protocol for Messenger Services Through Randomized ID Assignments

Messenger services have over the recent decade been the most dominant, ubiquitous, and widespread form of communication globally. While the service has evolved to enable reliable real-time communication between people across different technologies, there have been privacy and security concerns that were initially remediated by implementing TLS/SSL and E2E Encryption as a standard. However, new privacy challenges and security gaps have been identified and exploited through the capture and analysis of communication traffic metadata. These methods exploit the use of readily available advanced machine learning and data mining algorithms to identify users’ communication networks and patterns without reading the actual messages sent between end-users just by analyzing readily available metadata such as the sender and receiver IDs, time sent, and communication frequency. To close these gaps the need to anonymize users’ communications while maintaining reliable contact with each other is necessary. Randomized anonymization of metadata parameters can ensure it becomes nearly impossible for current analytics algorithms to identify user patterns from communication traffic over time. Also, to guarantee seamless communication between users with changing identities there needs to be a real-time contact exchange protocol enabling users to randomly change their IDs and secretly inform other users in their contacts without the physical intervention or involvement of the human user. This research paper proposes a solution through the use of a randomized contact reassignment and exchange protocol by using the PKI encryption protocol to share its new identity with its existing contacts defeating the creation of traceable logs over time.

The Impact of Rate Adaptation Algorithms on Wi-Fi-Based Factory Automation Systems.

Factory automation systems based on the IEEE 802.11 Wi-Fi standard may benefit from its Multi-Rate Support (MRS) feature, which allows for dynamically selecting the most suitable transmission rate for the targeted application context. The MRS is implemented by means of rate adaptation algorithms (RAAs), which has already demonstrated to be effective to improve both timeliness and reliability, which are typically strict requirements of industrial real-time communication systems. Indeed, some of such algorithms have been specifically conceived for reliable real-time communications. However, the computational complexity of such algorithms has not been effectively investigated yet. In this paper, we address such an issue, particularly focusing on the execution times of some specific rate adaptation algorithms, as well as on their impact on the automation tasks. In this respect, after a formal description of the algorithms, we present the outcomes of an extensive experimental session, which includes practical measurements and realistic simulations. The obtained results are encouraging, since the measured execution times indicate that rate adaptation algorithms can be profitably adopted by industrial automation systems, allowing for improving their reliability and timeliness without impacting on the overall performance.

The use of information and communication technologies in Latin American dentists: a cross-sectional study from Ecuador

BackgroundThe use of information and communication technologies (ICTs) provide the tools for enabling fast and reliable real-time communications, as well as the transfer of information between dental professionals and their patients. However, little is known about the frequency and preference of ICTs among Latin-American dentists. Our study aims to fill this gap by assessing different aspects related to ICTs, mainly the frequency of use, perceptions, and barriers among Ecuadorian dentists.MethodsAn anonymous, cross-sectional survey-based study was conducted among 342 Ecuadorian dentists. The final questionnaire included 13 items related to the frequency of use, perceptions, and barriers of ICTs. Bivariate analysis was performed by using chi-squared testing to explore the association between the independent variables and the intended use of ICTs, as well as to characterize the perceptions and barriers related to ICTs.ResultsIn general, most participants reported the use of ICTs to communicate with colleagues (99.7%), and patients (96.2%), while only 63.5% reported using ICTs to obtain academic information in their daily practice. WhatsApp was rated as the most used ICT for communicating with colleagues and patients. A majority of participants considered that ICTs can be useful for facilitating continuing dental education (92.1%), searching new work opportunities (91.5%), promoting health (90.1%), working with colleagues and other health professionals (91.2%), promoting their professional services (90.6%), and for resolving clinical cases (87.7%). On the subject of barriers, privacy and security concerns about personal and/or patient information was the biggest concern among dentists (65%), followed by lack of time to learn how to use and/or use ICTs (48%), lack of mobile internet access (28.1%), and lack of internet access at work (24.9%).ConclusionIn our study, we found that Ecuadorian dentists had a high usage rate of ICTs, mainly for communicating with other colleagues and patients, while the academic use of technology remains a comparatively underused application. Most of the participants surveyed had a positive perception towards ICTs, while privacy and security concerns were identified as the main barrier. Older age was associated with a less favourable perception toward ICTs, as well as an increased likelihood of reporting barriers related to the use of technology.

REA-6TiSCH: Reliable Emergency-Aware Communication Scheme for 6TiSCH Networks

From the perspective of the emerging Industrial Internet of Things (IIoT), the 6TiSCH working group has been created with the main goal to integrate the capabilities of the IEEE 802.15.4e time-slotted channel hopping (TSCH) with the IPv6 protocol stack. In order to support time-critical applications in IIoT, reliable real-time communication is a key requirement. Specifically, aperiodic critical traffic, such as emergency alarms, must be reliably delivered to the destination-oriented directed acyclic graph root within strict deadline bounds to avoid system failure or safety-critical situations. Currently, there is no mechanism defined in the 6TiSCH architecture for timely and reliably handling of such traffic and its prioritization over the noncritical one. In this article, we introduce REA-6TiSCH, a reliable emergency-aware communication scheme to support real-time communications of emergency alarms in 6TiSCH networks. In REA-6TiSCH, the aperiodic emergency traffic is opportunistically enabled to hijack transmission cells preassigned for the regular periodic traffic in the TSCH schedule. Moreover, we introduce a distributed optimization scheme to improve the probability that an emergency flow is delivered successfully within its deadline bound. To the best of our knowledge, this is the first approach to incorporate emergency alarms in 6TiSCH networks. We evaluate the performance of REA-6TiSCH through extensive simulations and the results show the effectiveness of our proposed method in handling emergency traffic compared to the Orchestra scheme. Additionally, we discuss the applicability of REA-6TiSCH and provide guidelines for real implementation in 6TiSCH networks.

An Efficient Authentication Scheme for Intra-Vehicular Controller Area Network

Communication in modern cars is managed by a controller area network (CAN) bus protocol and its extensions for electronic control units (ECUs). The CAN bus is a preferred method for reliable real-time broadcast communication. However, unprotected CAN communications make the vehicles vulnerable to a variety of practical malicious wired/wireless attacks. In this work, we analyze the existing frame-level authentication protocol and identify weaknesses and limitations. To address this, we provide a protocol suite for entity authentication, key management, a secure message flow for remote transmission request frames and session key update to be applied for vehicle connection with external devices. We prove the security of our protocol in the random oracle model and assess its resistance against known attacks. We formally verify the security of our protocol using the Tamarin tool. Our simulation results indicate that our protocol improves efficiency.

Decoupling Control Strategy of IPT System Based on Optimal Efficiency Load Tracking

The inductive power transmission system is applied to urban rail transit. Due to the limitations of the volume and coupling coefficient of the inductive coupling mechanism and the fact that the fluctuation of air gap in its movement will cause the fluctuation of mutual inductance value, DCDC booster link should be added to the side, rectifying side, to improve the output voltage level and stability. At present, most of the existing control strategies are based on the original side information communication. However, in the application of dynamic wireless charging in urban rail transit, the primary and secondary side coils are in the process of relative movement, so it is relatively difficult to establish reliable real-time communication, and it is easy to be interfered by electromagnetic transmission process, resulting in large errors. This paper analyzes the relationship between load and efficiency of IPT system applied to urban rail transit in detail and obtains the optimal load matching strategy of optimal efficiency. At the same time, an independent control strategy is proposed to eliminate the information communication of the primary and secondary sides and realize decoupling control. Finally, a simulation model is built to verify the effectiveness of the control strategy.

Teacher facilitation support in ubiquitous learning environments

ABSTRACTTeacher support for students in ubiquitous learning environments is challenging owing to physical distance and a lack of reliable real-time multimedia-rich communication. This is further complicated because the learning process is dynamic and problems need quick resolution. Given these challenges, this study proposes an architecture for a teacher facilitation support system. The system was implemented in the form of an interactive teacher dashboard. The interface also generates possible solutions to learning challenges while leaving the ultimate decision up to the teacher. The system feasibility was tested by work-through scenarios designed and validated by two experts. The system usability was evaluated using the System Usability Scale by 40 potential users. The findings revealed that the dashboard has good feasibility and usability for providing teachers relevant information about their students’ learning progress in ubiquitous learning environments. It also enabled opportunity for pedagogical intervention when needed.

Modified Advanced Encryption Standard Algorithm for Reliable Real-Time Communications

Ensuring the security of data while being transmitted or stored is a very important issue for companies and end users. Cryptography is used to transfer the data in a form that is not understood by anyone apart from the intended recipients. The advanced standard encryption algorithm (AES) is one of the most secure encryption algorithms. However, due to the speed issue and computational complexity, it is not suitable for real time applications. In this paper, a modified scheme is developed for the encryption/decryption by modifying the MixColumns stage in the AES algorithm in order to increase the speed of the encryption/ decryption while maintaining the complexity level of the design to keep the security level equivalent to AES. The results show that the proposed modification increases the speed of the encryption/decryption in real time applications up to 150% in the encryption process and up to 500% in the decryption process.

X-l ap

Networked control applications for cyber-physical networks demand predictable and reliable real-time communication. Applications of this domain have to cooperate with network protocols, the operating system, and the hardware to improve safety properties and increase resource efficiency. In consequence, a cross-layer approach is necessary for the design and holistic optimisation of cyber-physical systems and networks. This paper presents X-L ap , a cross-layer, inter-host timing analysis tool tailored to the needs of real-time communication. We use X-L ap to evaluate the timing behaviour of a reliable real-time communication protocol. Our analysis identifies parts of the protocol which are responsible for unwanted jitter. To system designers, X-L ap provides useful support for the design and evaluation of networked real-time systems.

Traffic Planning for Time-Sensitive Communication

Many industries, including the automotive industry and industrial automation, have a need for reliable real-time communication. To satisfy this need, industry-specific, often proprietary, solutions have been developed in recent decades. Time-sensitive networking (TSN) is addressing a grand unification of these existing technologies to leverage cross-industry cost efficiency as well as to guarantee a stable growth path of communication capabilities. While the functionality of time-sensitive networking is exhaustively standardized in IEEE 802.1, configuration standards for TSN are largely missing. Thus, in this article we review the IEEE TSN standards, in particular 802.1Qbv, and continue to illustrate a reference model for traffic planning for time-sensitive communication. Furthermore, the article references a detailed technical report describing the complete model, which is ideally suited as a starting point for standardization and ensures the interoperability of future TSN traffic planning tools.

Optimal scheduling of the flexray static segment based on two-dimensional bin-packing algorithm

FlexRay is a reliable and hard real-time in-vehicle communication protocol that is strongly promoted by car manufacturers as the de facto standard in the automotive domain. The protocol offers both a time-triggered and an eventtriggered architecture. This paper focuses on the optimal scheduling of the time-triggered component of FlexRay known as the static (ST) segment using a two-dimensional bin-packing technique. To maximize the bandwidth utilization in the ST segment, a fast heuristic as well as an efficient integer linear programming approach are proposed. Our methods directly schedule signals into slots including frame packing, according to signal-based data scheduling and the slot/ cycle multiplexing mechanisms presented by the latest version of the FlexRay protocol. The benefits of our proposed methods are demonstrated by extensive experiments on synthetic and an automotive X-by-wire system case study. An additional test case is examined to emphasize the superior performance of the proposed approach relative to that of existing optimal scheduling approaches.

Assignment of Segmented Slots Enabling Reliable Real-Time Transmission in Industrial Wireless Sensor Networks

Industrial wireless sensor networks (IWSNs) have the potential to contribute significantly in areas such as cable replacement, mobility, flexibility, and cost reduction. Nevertheless, the industrial environment that the IWSNs operate in is very challenging because of dust, heat, water, electromagnetic interference, and interference from other wireless devices, which make it difficult for current IWSNs to guarantee reliable real-time communication. In this paper, we present a novel method based on the segmented slot assignment, fast slot competition, and free node concept that will improve the reliability and real-time communication significantly so that more advanced applications can be enabled. The main purpose of the algorithms is to improve the retransmission efficiency for time-division-multiple-access-based multihop IWSNs by using limited shared slot resources more efficiently. More importantly, the proposed algorithms support efficient slot rescheduling caused by link or node failure. We evaluate the proposed methods by using simulations and a real implementation targeting monitoring of welder machines. Our obtained results show that the proposed method outperforms the first published and most widely used IWSN standard called WirelessHART.

CDMA VPDN-Based Wireless Data Communication System for Mobile Pipeline Patrol

Communication is the basic method to guarantee oil transportation command and scheduling of mobile long-distance pipeline and is the nervous system of the mobile pipeline. Based on the characteristics such as varied topography of the region it extends, long distance between stations, large volume of data transmitted and high requirement for security and relying on the private network of Telecom CDMA VPDN, the wireless data communication system for pipeline patrol integrating task management, service filing, real-time communication and positioning & navigation is established. The experiment proves that the system establishes safe and reliable real-time communication and achieves desired effects and smooth high-efficient upstream & downstream data transmission. It is of significance to improve patrol efficiency and quality and to guarantee oil transportation security of the pipeline.

Integration of a Wireless I/O Interface for PROFIBUS and PROFINET for Factory Automation

Cost related to the wiring of sensors and actuators in the manufacturing industry is rapidly increasing with the number of field devices. Complex engineering as well as cable wear and tear are important factors. For over a decade, fieldbuses have been the dominating approach to simplify installation, reduce engineering efforts, and increase reliability at the field level. The next step in this process is to introduce wireless communication in certain problematic parts of the field network. In order to do this, a reliable real-time communication system, designed to cope with the harsh environments where factory automation systems are employed, is required. The wireless interface for sensors and actuators (WISA), with its two subconcepts WISA-power and WISA-com, is such a system. This paper discusses how the WISA concept can be efficiently integrated into wired field networks for factory automation-both state-of-the-art [process fieldbus decentral peripherals (PROFIBUS DP)] and new (PROFINET IO) networks. We propose amendments to WISA, which will improve the 802.11b/g coexistence and harmonize the integration of WISA for sensor/actuator communication in, e.g., PROFINET IO systems. The suggested improvements relate to both the radio protocol in order to improve coexistence with other wireless technologies as well as concepts for the integration of WISA into the field network of PROFINET/PROFIBUS.

Algorithms for Server Placement in Multiple-Description-Based Media Streaming

Multiple description coding (MDC) has emerged as a powerful technique for reliable real-time communications over lossy packet networks. In its basic form, it involves encoding a media stream into r substreams that are sent independently from a source to a destination. Each substream (or description) can be decoded independent of the other r-1 substreams. With every successful reception of a substream, the quality of the decoded signal improves. In this paper, we consider the problem of placing a set of servers in the network such that a desired quality of service can be provided to a community of clients that request MDC-coded traffic. We formulate the server placement (SP) problem, with the goal of identifying the minimum number of server locations that can provide r descriptions to a set of clients such that the delay associated with each path from a chosen server location to a given client is bounded by a given delay constraint and the total ldquounreliabilityrdquo associated with the group of paths to a given client is also upper bounded. We show that the SP problem belongs to the class of NP-complete problems. We propose a mixed-integer linear programming (MILP) formulation and an efficient heuristic solution for the SP problem. Simulations are conducted to evaluate the performance of the proposed algorithm and compare it with the optimal solution provided by the MILP solution.

Feedback control of the lower hybrid power deposition profile on Tore Supra

The Tore Supra facility is well suited to study ITER relevant topics such as the real-time control of plasma current and the sustaining of steady-state discharges. This work describes a tool that was recently developed and implemented on Tore Supra to control in real time, by means of the direct knowledge of the suprathermal electron local emission profile, the width of the lower hybrid power deposition profile. This quantity can be considered to some extent equivalent to the width of the plasma current density profile in case of fully non-inductive discharges. This system takes advantage of an accurate hard x-ray diagnostics, of an efficient lower hybrid additional heating and of a reliable real-time communication network. The successful experiments carried out to test the system employed, as actuators, the parallel refractive index n// and the total power PLH. The control of the suprathermal electron local emission profile through n// was also integrated with the feedback control of the total plasma current IP with PLH and of the loop voltage Vloop with the central solenoid flux. These results demonstrate that the system is robust, reliable and able to counterbalance destabilizing events. This tool can be effectively used in the future in fully non-inductive discharges to improve the MHD stability and to maintain internal transport barriers or lower hybrid enhanced performance modes. The real-time control of the lower hybrid power deposition profile could also be used in conjunction with the electron-cyclotron radiofrequency heating for synergy studies.

Reliable real-time communication in can networks

Controller area network (CAN) is a fieldbus network suitable for small-scale distributed computer controlled systems (DCCS), being appropriate for sending and receiving short real-time messages at speeds up to 1 Mbit/sec. Several studies are available on how to guarantee the real-time requirements of CAN messages, providing preruntime schedulability conditions to guarantee the real-time communication requirements of DCCS traffic. Usually, it is considered that CAN guarantees atomic multicast properties by means of its extensive error detection/signaling mechanisms. However, there are some error situations where messages can be delivered in duplicate or delivered only by a subset of the receivers, leading to inconsistencies in the supported applications. In order to prevent such inconsistencies, a middleware for reliable communication in CAN is proposed, taking advantage of CAN synchronous properties to minimize the runtime overhead. Such middleware comprises a set of atomic multicast and consolidation protocols, upon which the reliable communication properties are guaranteed. The related timing analysis demonstrates that, in spite of the extra stack of protocols, the real-time properties of CAN are preserved since the predictability of message transfer is guaranteed.

Reliable real-time communication in cooperative mobile applications

Embedded systems are expected to provide increasingly complex and safety-critical services that will, sooner or later, require the cooperation of several such systems for their fulfillment. In particular, coordinating the access to shared physical and information technological resources will become a general problem. Examples are mobile robots in industrial automation or car-to-car coordination for future traffic control applications. In such applications, cooperation is subject to strong real-time and reliability requirements. In this paper, we present an architecture that allows autonomous mobile systems to schedule shared resources in real-time using their own wireless distributed infrastructure. In this architecture, there is a clear separation between the application-specific scheduling part and the application independent communication part that constitutes the real-time and reliability hardcore of the system. The latter provides clock synchronization, real-time atomic multicast, and real-time group membership based on an IEEE 802.11 standard wireless LAN. An application prototype shows how the architecture can be used in future mobile cooperative applications.