Message Transmission Rate Research Articles

A Reinforcement Learning-Based Congestion Control Approach for V2V Communication in VANET

Vehicular ad hoc networks (VANETs) are crucial components of intelligent transportation systems (ITS) aimed at enhancing road safety and providing additional services to vehicles and their users. To achieve reliable delivery of periodic status information, referred to as basic safety messages (BSMs) and event-driven alerts, vehicles need to manage the conflicting requirements of situational awareness and congestion control in a dynamic environment. To address this challenge, this paper focuses on controlling the message transmission rate through a Markov decision process (MDP) and solves it using a novel reinforcement learning (RL) algorithm. The proposed RL approach selects the most suitable transmission rate based on the current channel conditions, resulting in a balanced performance in terms of packet delivery and channel congestion, as shown by simulation results for different traffic scenarios. Additionally, the proposed approach offers increased flexibility for adaptive congestion control through the design of an appropriate reward function.

Spotted Hyena Optimization and Simulated Annealing-Based NLOS Nodes Localization Scheme for Improving Warning Message Dessimination in VANETs

An accurate localization technique is considered as the significant entity in vehicular ad hoc networks (VANETs) for facilitating emergency message data transmission in diversified critical safety applications. In VANETs, the system of global positioing is generally used for estimating the position of the vehicles in the network for attaining neighborhood awareness in the event of warning message dissemination. However, the existence of green foliages, buildings, indoor parking lots and urban streen canyons introduces NLOS situation that introduces unwanted errors that crumbles the degree of data dissemination in emergency situations. In this paper, spotted hyena and simulated annealing optimization algorithm (SHSAOA)-based positioning scheme was proposed for precise estimation of NLOS nodes. İt included the advantages of improved simulated annealing (SA) integrated into SHOA for establishing better balance between the process of exploitation and exploration in the search space. This positioning approach generated candidate solutions by deriving the merits of the trajectory-based charateristics of SA throughout the algorithmic development process in order to improve the local optimization process. This proposed SHSAOA utilized the distance infotmation that are associated with the vehicle trajectory, number of vehicles and error in distance information for assessing the precise location of the NLOS nodes in the network. The simulation results of the proposed SHSAOA scheme confirmed minimized localization error with maximized accuracy in transmission, warning message transmission rate, channel utilization degree and neighborhood awareness degree with different vehicular density and NLOS nodes.

Provably Secure with Efficient Data Sharing Scheme for Fifth-Generation (5G)-Enabled Vehicular Networks without Road-Side Unit (RSU)

The vehicles in the fifth-generation (5G)-enabled vehicular networks exchange the data about road conditions, since the message transmission rate and the downloading service rate have been considerably brighter. The data shared by vehicles are vulnerable to privacy and security issues. Notably, the existing schemes require expensive components, namely a road-side unit (RSU), to authenticate the messages for the joining process. To cope with these issues, this paper proposes a provably secure efficient data-sharing scheme without RSU for 5G-enabled vehicular networks. Our work included six phases, namely: TA initialization (TASetup) phase, pseudonym-identity generation (PIDGen) phase, key generation (KeyGen) phase, message signing (MsgSign) phase, single verification (SigVerify) phase, and batch signatures verification (BSigVerify) phase. The vehicle in our work has the ability to verify multiple signatures simultaneously. Our work not only achieves privacy and security requirements but also withstands various security attacks on the vehicular network. Ultimately, our work also evaluates favourable performance compared to other existing schemes with regards to costs of communication and computation.

The Optimization of Classroom Teaching in Colleges and Universities Based on Network Topology

In order to improve the teaching effect of programming courses, this article applies network topology to the construction of programming course teaching platform system and constructs a teaching framework combined with intelligent teaching mode. In addition, this article takes the opportunistic social network composed of mobile smart terminal devices as the application background and briefly introduces the concept, characteristics, and application scenarios of the opportunistic social network. In addition, the typical message forwarding algorithm currently studied in this paper is analyzed. Taking into account the social attributes and forwarding willingness of nodes, in order to increase the message transmission rate and reduce message transmission delay and network overhead, two message transmission strategies are proposed to improve the operating effect of the programming course teaching platform. Finally, this paper verifies the effectiveness of the network topology in the teaching of the algorithm and programming of the intelligent teaching mode through experimental research.

Wireless Covert Communications Aided by Distributed Cooperative Jamming Over Slow Fading Channels

In this paper, we study covert communications between a pair of legitimate transmitter-receiver against a watchful warden over slow fading channels. There coexist multiple friendly helper nodes who are willing to protect the covert communication from being detected by the warden. We propose an uncoordinated jammer selection scheme where those helpers whose instantaneous channel gains to the legitimate receiver fall below a pre-established selection threshold will be chosen as jammers radiating jamming signals to defeat the warden. By doing so, the detection accuracy of the warden is expected to be severely degraded while the desired covert communication is rarely affected. We then jointly design the optimal selection threshold and message transmission rate for maximizing covert throughput under the premise that the detection error of the warden exceeds a certain level. Numerical results are presented to validate our theoretical analyses. It is shown that the multi-jammer assisted covert communication outperforms the conventional single-jammer method in terms of covert throughput, and the maximal covert throughput improves significantly as the total number of helpers increases, which demonstrates the validity and superiority of our proposed scheme.

WITHDRAWN: A novel hybrid Optimized vehicle routes to enhance the vehicular ad hoc network communication

Abstract The population of the entire world keeps on increasing and it has resulted in an increase in transportation. As the vehicle density increases, traffic saturation problems arise frequently and this increases the travel time. To overcome these issues, the current article is aimed to design a novel Ant Colony based Temporarily Ordered (ACbTO) algorithm to suggest the vehicles with the shortest routes based upon the priority. Traffic Management Unit (TMU) acts as a control unit employed for gathering vehicle information, data transmission, cluster formation, and route suggestion. Also, it allows communication between the vehicles that enhances the traveling experience of the occupants. This proposed technique has increased the message transmission rate and reduced the travel distance, packet loss, average cluster duration, and also energy consumption to a larger extend. Hence, the performance of the proposed system is compared with the advanced works and better efficiency is achieved by reduced packet loss and low energy consumption.

Understanding the Impact of the PC5 Resource Grid Design on the Capacity and Efficiency of LTE-V2X in Vehicular Networks

Vehicular communications will foster mobility services and enable mass adoption of future autonomous vehicles, interchanging huge amount of data acquired from vehicles’ sensors. 3GPP Release 14 presents the first standard for supporting V2X in LTE. Several enhancements are introduced, including a new arrangement of the physical resource grid, where subchannels are the minimum resource unit instead of Resource Blocks. The resource grid is defined by several design parameters, some of them with constraints imposed by 3GPP specifications, that affect the maximum message transmission rate and efficiency of the system. Moreover, the optimum choice of these parameters is closely linked to message length, which is another variable parameter. This paper provides an analysis of the relationship between these design parameters (Resource Block per Subchannel, Transport Block Size Index, and coding rate), message size, and the system’s maximum capacity and efficiency. In doing so, we do not consider channel reuse or radio transmission characteristics because the focus of this paper is trying to find the resource grid design parameters that optimize system capacity, which is a very important aspect to consider by V2X operators.

A Sigfox Energy Consumption Model.

Sigfox has become one of the main Low-Power Wide Area Network (LPWAN) technologies, as it has attracted the attention of the industry, academy and standards development organizations in recent years. Sigfox devices, such as sensors or actuators, are expected to run on limited energy sources; therefore, it is crucial to investigate the energy consumption of Sigfox. However, the literature has only focused on this topic to a very limited extent. This paper presents an analytical model that characterizes device current consumption, device lifetime and energy cost of data delivery with Sigfox. In order to capture a realistic behavior, the model has been derived from measurements carried out on a real Sigfox hardware module. The model allows quantifying the impact of relevant Sigfox parameters and mechanisms, as well as frame losses, on Sigfox device energy performance. Among others, evaluation results show that the considered Sigfox device, powered by a 2400 mAh battery, can achieve a theoretical lifetime of 1.5 or 2.5 years while sending one message every 10 min at 100 bit/s or 600 bit/s, respectively, and an asymptotic lifetime of 14.6 years as the message transmission rate decreases.

Hybrid approach of parallel implementation on CPU–GPU for high-speed ECDSA verification

Since the advent of deep belief network deep learning technology in 2006, artificial intelligence technology has been utilized in various convergence areas, such as autonomous driving and medical care. Some services requiring fast decision making and action typically work seamlessly with edge computing service model. In autonomous driving of a connected vehicle with vehicle-to-everything (V2X) communication, roadside unit (RSU) acts as an edge computing device and it will make safer service by processing V2X messages fast, sent by vehicles or other devices. IEEE 1609.2 standard provides application message security technology to ensure the security and reliability of vehicle-to-vehicle communication messages. It uses elliptic curve digital signature algorithm (ECDSA) signatures based on the NIST p256 curve for message authenticity. In this paper, we investigate that RSU should be able to verify 3500 ECDSA signatures per second considering the expected maximum number of vehicles on nearby roads (e.g., during rush hour), message transmission rate, and IEEE 802.11p wireless channel capacity. RSU should satisfy this requirement without assistance of hardware-based cryptographic accelerator. For the requirement, we propose a hybrid approach of parallel ECDSA signature verification at high speed by using CPU and GPU, simultaneously. Moreover, we implemented the proposed method in various modern computing environments for RSU and edge computing devices. Through the experiments, we reach the conclusion that GPU can contribute to the required performance of ECDSA signature verification in RSU platform, which could not satisfy the above throughput only with CPU unit. The target platform with Intel Pentium E6500 CPU and GeForce GTX650 GPU can verify 5668 signatures per second with 30% utilization, while CPU in the platform can process only 2640 signatures. Even in a higher-performance edge computing device, we examine experimentally that the performance can be further improved by using the proposed hybrid approach.

DesCom: Routing Decision using Estimation Time in VDTN

VDTN was proposed as a disrupting network which is established on the paradigm of the delay-tolerant network. VDTN uses vehicular nodes to convey messages as, it permits sparse opportunistic network connectivity, which is considered by the low node density where the vehicular traffic is sporadic, and no end-to-end paths exist between nodes. The message bundle is directed from the sender to the receiver node based on the routing protocol decision. While Routing protocols take decisions based on different metrics like Time to live, Location, Remaining Buffer Size, meeting probability, etc. In this paper, a routing protocol named DesCom is proposed for Vehicular Delay-Tolerant Network under a highly suppressed and sparse environment. DesCom takes the decision based on Message TTL, Transmission rate, and Estimation time. Estimation time is calculated in our previous work. The protocol defines whether to direct the message to the requested node or search the other more suitable node to carry that data bundles. After compiling multiple simulations with different numbers of vehicles and comparing DesCom with other routing protocols it is concluded that DesCom has the least buffer time with low latency along with good delivery probability.

Detecting Flooding Attack and Accommodating Burst Traffic in Delay-Tolerant Networks

Delay-tolerant network (DTN) is developed to cope with intermittent connectivity and long delay in wireless networks. Due to limited connectivity, DTN is vulnerable to flooding attack in which malicious nodes flood the network with superfluous data to deplete the network resources. Existing works mitigate internal flooding attacks by rate limit to constrain the number of messages that nodes can generate per time slot. However, rate limit cannot flexibly accommodate burst traffic in which nodes may have sending demands higher than the rate limit for a short period. In this paper, we propose flooding detection based on encounter records (FDER) to detect flooding attack and yet allow legitimate burst traffic simultaneously. Nodes exchange their histories of encounter records (ER), which record the sent messages during their previous encounters. The ER history is used to infer a node's new message transmission rate over time and the number of forwarded replicas per message. The adversary nodes that send too many messages or replicas can thus be detected. Since ERs serve as useful tools for monitoring the sending behavior of nodes over a long time period, FDER could detect the burst traffic violation efficiently. We also design fairness policy (FP)—a fairness forwarding policy to ensure fairness in the delivery performance fairness between nodes with normal traffic and those with burst traffic. FP uses ER information to observe nodes’ rate of new message generation and adjust their forwarding priorities accordingly. Simulation results show that FDER can detect flooding attack at a higher accuracy and a lower delay compared to a state-of-the-art scheme with affordable overhead. Moreover, FP could mitigate the smart flooding attack and still provide the performance fairness to support bursty traffic scenario.

A node management scheme for stable P2P service in mobile ad-hoc networks

In a mobile ad-hoc network, multiple number of nodes can communicate with one another without the need for an infrastructure network. It is used in many different types of places, including military zones and disaster or hazardous areas. In a mobile ad-hoc network, each node acts both as a main agent of communication and a relay. Furthermore, each gives a weakness to the network or is subjected to vulnerabilities from malicious attacks due to their distinctive qualities, namely mobility and limited power. Accordingly, in order for stable P2P service, it is important to maintain the reliability and connectivity of the network at a high level. With existing schemes, it has often been the case that when defective nodes or malicious nodes are detected, it also causes damage to normal nodes. In scheme suggested in this paper, those nodes that have temporary defects but otherwise normal and can recovered are kept in the network but those that are defective or malicious are eliminated from the network, using trust values. The simulation was carried out to evaluate the performance of the proposed method. As a result, the message transmission rate even if the impact of a malicious node than the conventional method was demonstrated increased keeping the stable network topology.

A model for communication between resource discovery and load balancing units in computing environments

Resource overloading causes one of the main challenges in computing environments. In this case, a new resource should be discovered to transfer the extra load. However, this results in drastic performance degradation. Thus, it is of high importance to discover the appropriate resource at first. So far, several resource discovery mechanisms have been introduced to overcome this challenge, a majority of which neglect the fact that this important decision should be made in cooperation with other units existing in a computing environment. One of the units is load balancing. In this paper, we propose a model for communication between resource discovery and load balancing units in a computing environment. Based on the model, resource discovery and load balancing decisions are made cooperatively considering the behavior of running processes and resources capacities. These considerations make decisions more precise. In addition, the model presents the loosest type of coupling between resource discovery and load balancing units, i.e., message coupling. This feature provides a better scalability in size for the model. Comparative results show that the proposed model increases scalability in size by 7 to 15 %, cuts message transmission rate by 15 % and improves hit rate by 51 %.

Dual-channel chaos synchronization and communication based on a vertical-cavity surface emitting laser with double optical feedback

Using two orthogonal polarization mode outputs from a vertical-cavity surface emitting lasers (VCSEL) with double optical feedback as two chaotic carriers, a dual-channel chaos secure communication system is established, and the synchronization and communication performances of such a system are numerically investigated. The results show that under suitable operated condition, the time-delay signatures of two chaotic carriers originating from two linear polarization modes in the T-VCSLE with double optical feedback can be suppressed efficiently. Under the strong injection locking case, high-quality chaos synchronization between two corresponding modes of T-VCSEL and R-VCSEL can be realized by polarization-preserved optical injection from T-VCSEL to R-VCSEL. Moreover, the tolerance of the synchronization quality on the frequency detuning between T-VCSEL and R-VCSEL is enhanced with the increase of the injection strength. Adopting additive chaos modulation encryption scheme, two pieces of 500 Mbit/s encoded message can be hidden efficiently in the two chaotic carriers in the propagation process and can be successfully extracted at the receiver. Although Q factor decreases with the increase of message transmission rate, the values of Q factor for two channels are still larger than 6 for 6 Gbit/s message.

Maximally efficient protocols for direct secure quantum communication

Two protocols for deterministic secure quantum communication (DSQC) using GHZ-like states have been proposed. It is shown that one of these protocols is maximally efficient and that can be modified to an equivalent protocol of quantum secure direct communication (QSDC). Security and efficiency of the proposed protocols are analyzed and compared. It is shown that dense coding is sufficient but not essential for DSQC and QSDC protocols. Maximally efficient QSDC protocols are shown to be more efficient than their DSQC counterparts. This additional efficiency arises at the cost of message transmission rate.

Control-based p-persistent adaptive communication protocol

An enhancement to the CSMA p-persistent protocol family is proposed, based on a fully decentralized control that adjusts the message transmission rate of each node to the estimated density of surrounding transmitting nodes. The system does not require enumeration of nodes nor control messages, the only input to the control coming from the physical medium occupation. In addition to communication protocols, this technique can be used as inexpensive and efficient density estimation of physical entities in highly dynamic scenarios. Stability conditions are proposed by means of a rigorous theoretical investigation. We prove that our algorithm ensures stability even with unknown and time--varying network topologies. We show that good channel exploitation levels can be assured as well by suitably tuning the control parameters. A digital algorithm for practical implementation is proposed. The results are supported by simulation experiments.

Robust Stability and Performance of a p-Persistent Communication Protocol

AbstractA p-persistent transmission protocol, recently proposed in the literature, for a network of transmitting nodes sharing a common channel is studied. Such a protocol is based on a fully decentralized control that adjusts the message transmission rate of each node to the estimated density of surrounding transmitting nodes. The system does not require enumeration of nodes nor control messages, the only input to the control coming from the physical medium occupation. Stability conditions are considered under time-varying network topologies and delays. General stability conditions for tuning the control parameters are given which assure stability under arbitrary topology variations. It is shown that such conditions are conservative, penalize the network parameters and compromise the systems performance. Thus the problem is investigated in details in order to provide conditions in terms of performance. It is shown that under network symmetry assumption stability can be studied in terms of system eigenvalues even under topology switching. Moreover, under symmetry assumption, the problem has interesting connections with the known problem of the characterization of the eigenvalues of the adjacency matrix of a graph.

IP Transmission over TETRA Packet Data Service: Simulation and Measurement Results

This paper evaluates the packet data performance of Internet Protocol (IP) over TErrestrial Trunked RAdio (TETRA), focusing on the effects of packet size and message transmission rate. We performed a range of simulations to evaluate the average packet delay and packet failure probability corresponding to IP datagram transmission on the Packet Data CHannel (PDCH) in a TETRA cell. We employed IP packets of different sizes and we considered a number of different scenarios with respect to the number of users in a cell and datagram transmission rate. The simulation results offer TETRA operators the means for facilitating network planning and optimization of datagram-based services. Apart from the simulation, we also conducted an extensive measurement survey on the performance of IP over the TETRA PDCH. In particular, we carried out measurements in a client---server communication scenario with different datagram sizes and typical user mobility and radio propagation conditions. Measurement results include throughput, delay jitter, percentage of lost datagrams and out-of-order datagrams. The results obtained through our measurement survey can extent and enhance the simulation results because they are more realistic and consider user mobility as well as channel impairments.

An adaptive congestion control mechanism for intelligent broadband networks

The provision of novel multimedia services in broadband networks through intelligent network (IN) technology is a promising solution that guarantees fast deployment of new services and minimum changes to already operating networks. In this architecture, the broadband service control point (B-SCP) is the main actor in the processing of complex IN service requests. This centralized approach which is reflected in the multiplicity of tasks undertaken by the B-SCP in a broadband IN architecture, can easily lead to network performance degradation. Therefore, the presence of a congestion control mechanism operating at the level of calls is considered essential in order to protect the network nodes from overload conditions and to attain high levels of network performance. In this paper, we propose an adaptive congestion control mechanism (ACCM) which is able to guarantee the desirable quality of service under overload conditions. The proposed mechanism gradually reduces the message transmission rate from the source node to the destination node when overflow conditions have been detected, taking as feedback the buffer capacity state of the destination. Results, obtained by simulation show that the proposed ACCM improves the network performance by maximising the number of established calls and reducing the number of rejected calls.

Verified data transfer protocols with variable flow control

We present and verify a sliding window protocol which uses modulo- N sequence numbers to achieve reliable flow-controlled data transfer between a producer and a consumer connected by unreliable channels. The consumer's data needs are represented by a receive window whose size can vary with time. The producer entity sends segments of data words that lie within the consumer's receive window. The consumer entity sends acknowledgment, selective acknowledgment, and selective reject messages that inform the producer entity of the current receive window size, the data word next expected, and the reception (or lack of reception) of out-of-sequence data segments. Our protocol is, therefore, a proper extension of existing transport and data link protocol standards such as TCP, IS0 TP, HDLC, ADCCP, and so forth. We consider two types of unreliable channels. The first type, referred to as transport channels, can lose, duplicate, and reorder messages to an arbitrary extent, but impose an upper bound on message lifetimes (which can be very large, e.g., days). The second type, referred to as data link channels, can only lose messages. For both types of channels, we obtain the minimum value of N that ensures safe operation without imposing any constraints on the retransmissions of messages or on the data segment sizes. Thus, any retransmission or acknowledgment policy that optimizes the protocol's performance can be used. For transport channels, this value of N is a function of the maximum message transmission rate, the maximum message lifetime, and the maximum receive window size. For data link channels, this value of N is a function only of the maximum receive window size. We verify progress under three different liveness assumptions: retransmissions initiated by both entities, only by the producer entity, and only by the consumer entity. The protocol also satisfies a convenient noninterference safety property between the acknowledgement, selective acknowledgment, and selective reject messages. The protocols are specified as event-driven systems and verified hierarchically in two major stages. First, we verify that correct flow-controlled data transfer results if the sequence numbers in the channels satisfy certain correct interpretation bounds , irrespective of the types of errors that the channels may have. Second, for both transport and data link channels, we verify that the correct interpretation bounds are enforced by the corresponding minimum values of N . For the verification of the transport channel case, we use a system model with continuous measures of time in which real-time constraints can be formally specified and verified.