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Domain-based electronic and electrical (E/E) architectures have been regarded as a possible upgrade to distributed E/E architectures currently used in electric vehicles. In a distributed E/E design, E/E components are directly connected to the automobile bus. Domain-based architectures split E/E components into distinct domains depending on their functions, which clearly benefits software upgrading and wire harness reduction. However, due to its heterogeneous topology with multiple network protocols, domain-based E/E architecture introduces complicated multilink and multinode delays into the control loop. The delays may degrade and even deteriorate the stability of adaptive cruise control (ACC) employing domain-based E/E architecture. To this end, this article proposes a heterogeneous-topology loop delay analysis by introducing a notion of poly-service loop delay. With a graphical pattern, the analytical process is presented in depth. The worst-case loop delay is calculated using an upper-boundary mathematic equation. Then, a hierarchical cyber-physical control method for ACC is designed. The upper level is intended to achieve desired acceleration based on vehicle and intervehicle motion states. And the lower level is intended to mitigate the negative impact of loop delays and provide reliable acceleration tracking. The results of cosimulation and hardware-in-loop experiment verify effectiveness of proposed approaches. [ABSTRACT FROM AUTHOR]

Network data constantly evolves with new network applications and protocols. There is a need for robust techniques to detect anomalous behaviour. Offline models trained with static data lose validity when new variants of traffic emerge. They require retraining but the need for ground truth and lengthy training times make this task challenging. Meanwhile, online models which detect outliers in streaming data are susceptible to the curse of dimensionality and natural variability. Today’s anomalies may be tomorrow’s new traffic and existing methods do not provide a way to differentiate between them. We propose a framework that makes the most of both approaches: an offline deep learning model extracts features of normal traffic and provides a bias for an online outlier detection model to select data for training. The online model retains its previously learnt knowledge and retrains itself with new data. Online thresholds are updated in a drifting manner and the Mann-Whitney U test is incorporated to prevent inaccurate updates. We perform analysis on the scores, develop heuristics to detect new traffic and evaluate using three deep learning models and four outlier detection methods on the UNSW-NB15 and CTU-13 datasets. The framework improves upon any individual offline or online models in isolation. [ABSTRACT FROM AUTHOR]

Time-sensitive networking (TSN) is an industry-standard networking protocol that is widely deployed in safety-critical industrial and automotive networks thanks to its quality-of-service (QoS) mechanisms, esp. deterministic transmission and bounded end-to-end delay for time-triggered (TT) flows. In this article, we focus on TT flows and address the issue of fault tolerance against permanent and transient faults with both spatial and temporal redundancy. We present an efficient heuristic algorithm for online incremental rerouting and rescheduling of disrupted flows, assuming the paths and schedules of existing flows stay fixed. It is complementary to and can be combined with offline routing and scheduling algorithms for achieving fault tolerance based on frame replication and elimination for reliability (FRER) (IEEE 802.1CB). Performance evaluation shows that our approach is able to better recover the system’s degree of redundancy (DoR) and has a higher acceptance rate than related work. [ABSTRACT FROM AUTHOR]

Emerging embedded systems, such as autonomous vehicles, demand highly efficient remote data transfer, whereas existing networking hardware and protocols cause high communication latency and CPU consumption. In this article, we propose embedded RDAC (eRDAC), an efficient and reliable remote direct access and control solution for embedded systems. The proposed remote access controller in eRDAC has a two-layer protocol offload engine that employs the command/response protocol on UDP to ensure the data reliability and security, and a multichannel DMA controller with configurable priority to improve the efficiency. Besides, a reusable hardware Ethernet MAC is implemented to support not only remote access commands but also standard Ethernet communication. We implement eRDAC on FPGA and the corresponding software in the Linux system. Experimental results show that eRDAC can reduce the latency of remote I/O reading/writing by 74.3%/74.9% ($3.76\times /3.98\times $ performance improvement) and reduce the latency of remote memory reading and writing with 1024B by 54.2% compared to the socket-based communication. Meanwhile, eRDAC can cut off the consumption of the remote processor and achieve 0.250mJ/Mb energy consumption with only 25-mW power. [ABSTRACT FROM AUTHOR]

Entanglement-based quantum networks can provide unconditionally secure communication by distributing entangled pairs between distant end nodes. To achieve end-to-end entanglement distribution, multiple operations of entanglement swapping in a quantum repeater chain are always required. However, due to the non-determinism of entanglement swapping caused by imperfect physical devices, the execution pattern of swapping operations has a direct impact on the performance of entanglement distribution, which can be categorized into an entanglement access control (EAC) problem. In this article, we attribute the EAC problem to two aspects: the matching optimization within quantum nodes, and the swapping conflict avoidance between quantum nodes. Accordingly, we propose an asynchronous entanglement distribution protocol which contains a custom weighted maximum matching algorithm, and a reliable signaling interaction mechanism to avoid a swapping conflict, respectively. Based on the proposed protocol, quantum repeaters autonomously decide their behaviors and spontaneously construct the end-to-end entangled pairs asynchronously. Simulation results show that our protocol can significantly improve the entanglement distribution rate and fidelity of end-to-end entangled pairs while simplifying the deployment and management process of the quantum networks. [ABSTRACT FROM AUTHOR]

Bundle protocol (BP) was proposed as the core protocol of delay/disruption-tolerant networking for space. A hybrid reliable transmission mechanism based on integrating "proactive" retransmission and "reactive" retransmission of BP bundles has been presented as a means of achieving highly reliable file/data delivery in deep-space communications. Transmission overhead imposed by reliable delivery of data packets/bundles is consistently one of the key factors for efficient data delivery in space communications. It is especially important in deep-space networks, where the available electrical power on spacecraft for data delivery is a scarce resource but substantial energy is needed to propagate data over an extremely long deep-space channel. In this article, a detailed study of the transmission overhead for the hybrid retransmission approach of BP for reliable deep-space communications is presented. An analytical framework is presented for modeling the transmission overhead of BP as influenced by variations in channel quality, file size, bundle size, and retransmission timeout interval length. Its energy resource consumption is also briefly discussed. The analytical framework is validated by realistic file transfer experiments using a PC-based testbed infrastructure; the framework is found to be able to predict the performance with respect to the transmission overhead of BP. [ABSTRACT FROM AUTHOR]

Due to the explosive increase of electric vehicles (EVs) and universal charging stations (CS), achieving fast authentication is an important topic in the vehicle-to-grid (V2G) network at present. Fast authentication cannot only forcefully defend potential adversaries but also can greatly speed up the charging process between EVs and CSs. Although many researchers have realized this problem and proposed some lightweight cryptographic protocols for fast EV charging, desired security features are not entirely satisfied, such as man-in-the-middle attacks, replay attacks, and impersonation attacks. In this article, we propose an ultra super fast authentication protocol for EV charging by utilizing the characteristics of extended chaotic maps. Furthermore, in view of the unsolved security issues mentioned previously, our proposed protocol can provide elaborate solutions to eliminate these possible attacks in a provable manner. Finally, compared with the relevant authentication protocols for V2G network, the communication and computation costs of our protocol are decreased a lot. [ABSTRACT FROM AUTHOR]

As one of the main data transport protocols of delay/disruption-tolerant networking (DTN), Licklider transmission protocol (LTP) is designed to provide reliable data delivery in an interplanetary Internet environment characterized by frequent and lengthy link disruptions and extremely long signal propagation delays. Some studies have been done on the performance of LTP in cislunar and Mars communications. However, to date the effect of link disruption on LTP for Mars communications has received little attention. In this paper, an analytical framework is presented for the effect of link disruption on reliable data delivery and performance of LTP in Mars communications. The analysis focuses on how various link disruptions affect the number of transmission attempts, the consequent round-trip time (RTT) of data exchange, and the resulting goodput performance of LTP for reliable data block delivery in Mars communications. The analytical framework is validated by means of realistic data block transmission experiments using a PC-based experimental infrastructure, and it can be used to predict the performance of LTP over a deep-space vehicle communication channel in presence of link disruption. [ABSTRACT FROM AUTHOR]

One of the key challenges in computer networks is network security. For securing the network, various solutions have been proposed, including network security protocols and firewalls. In the case of so-called packet-filtering firewalls, policy rules are implemented to monitor changes to the network and preserve the required security level. Due to the dramatic increase of devices, however, and herewith the rapid increase of the size of the policy rules, firewall policy anomalies occur more frequently. This requires careful implementation of the policy rules to ensure cost-efficient solutions for anomaly detection to support network security. In this study, we present an anomaly detection framework for detecting intrafirewall policy anomaly rules. The framework supports the simulation of packets through the firewall ruleset for validating and enhancing the security level of the network. The framework is validated using four different types of firewall policy anomalies. Experimental results demonstrate that the framework is effective and efficient in detecting firewall policy anomalies. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the performance of non-orthogonal multiple access (NOMA)-based overlay cognitive integrated satellite-terrestrial relay network with secondary network selection, where the selected secondary network accesses the licensed spectrum by assisting the communication of primary network with amplify-and-forward protocol. Besides, NOMA techniques are used to improve the spectrum efficiency. Specifically, the closed-form expressions of outage probability (OP) for both primary network and secondary network are obtained. To get inherent insights, the asymptotic analysis of OP is further derived at high signal-to-noise ratios. Moreover, the diversity orders of the both networks are further provided. Finally, Monte Carlo simulations are given to valuate our analysis, and the effects of key parameters on system performance are revealed. Through the comparison between orthogonal multiple access (OMA) scheme and NOMA scheme, the superiority of our proposed scheme is proved. [ABSTRACT FROM AUTHOR]

Most existing network communication systems, such as the Internet, are built around the TCP/IP protocol stack. However, TCP/IP cannot effectively support the upcoming network communication systems with more wireless communication links and higher requirements in terms of throughput, latency, and reliability. In this article, we introduce a general network communication protocol design based on batched network coding (BNC), which includes the existing framework as a special case and whose design can be guided by channel coding theory. BNC-based protocols can have significant throughput gain for single-hop or multihop wireless communications and provide better trade-off among throughput, latency and reliability. [ABSTRACT FROM AUTHOR]

Satisfying the stringent 5G quality of service requirements necessitates efficient resource utilization by mobile networks. Consequently, we argue that multi-connectivity (MC) is an effective solution to leverage the limited radio resources from multiple base stations in order to enhance user throughput, provide seamless connectivity, and increase data reliability. For this, we study different MC architectures, where distinct network entities and protocol layers are used to split or aggregate the user traffic. The benefits and challenges of MC are analyzed as well as the open issues that network/device vendors and mobile network operators have to address for its use. Finally, through experimental evaluations, we illustrate the importance of MC design decisions for overall network performance. [ABSTRACT FROM AUTHOR]

With the increasing connectivity between the Electronic Control Units (ECUs) and the outside world, safety and security have become stringent problems. The Controller Area Network (CAN) bus is the most commonly used in-vehicle network protocol, which lacks security mechanisms by design, so it is vulnerable to various attacks. In this paper, we propose a novel intrusion detection model called CNN-LSTM with Attention model (CLAM) for the in-vehicle network, especially CAN. The CLAM model uses one-dimensional convolution (Conv1D) to extract the abstract features of the signal values at each time step and feeds it into the Bidirectional Long Short Term Memory (Bi-LSTM) to extract the time dependence. By combining the attention mechanisms, we calculate the weight of each hidden state output by Bi-LSTM and perform a weighted summation, so that the model focuses only on locally important time steps, which can improve the convergence speed of the model and prediction accuracy. The proposed model uses the bit flip rate to extract continuous signal boundaries in the 64-bit CAN data, so it does not need to parse the CAN communication matrix and is suitable for different vehicles. The extensive evaluation results demonstrate that our proposed CLAM model can effectively detect CAN attacks, with an average F1-score of 0.951 and an error rate of 2.16%. Compared with the work in related research fields, the accuracy of attack detection is improved by 2.5%. [ABSTRACT FROM AUTHOR]

The low-rate denial of service (LDoS) attack mainly exploits security vulnerabilities of adaptive mechanisms in network protocols and application services. The high-rate attack pulses within a short time interval are sent periodically, which will result in the degradation of service quality. The attack traffic is similar to normal traffic from legitimate users in the network, consequently, it is easy to escape the traditional detection methods because of its intermittence. Research works have demonstrated that there are fractal characteristics (self-similarity) of the network traffic over the large scale of time. Although the fractal characteristics of the network traffic will be changed under the LDoS attack, the variations of the fractal characteristics in some network states are not apparent in real-time detection. Based on the fractal characteristics, the fractal residual of the network traffic is analyzed through the Hurst parameters calculating process by R/S algorithm in this article. It can be found that the fractal residual of the network traffic can better reflect the different states of the LDoS attack. Combining the idea behind the sliding window, a novel fractal residual based real-time detection (FR-RED) method of the LDoS attack is proposed. The effectiveness of the method in this article is verified by performing some experiments on two platforms, the NS2 and test-bed. The results manifest the beginning and end of the LDoS attack can be estimated in real-time with high detection accuracy. [ABSTRACT FROM AUTHOR]

Wireless blockchain network is proposed to enable a decentralized and safe wireless networks for various blockchain applications. To achieve blockchain consensus in wireless network, one of the important steps is to broadcast new block using wireless channel. Under wireless network protocols, the block transmitting will be affected significantly. In this work, we focus on the consensus process in blockchain-based wireless local area network (B-WLAN) by investigating the impact of the media access control (MAC) protocol, CSMA/CA. With the randomness of the backoff counter in CSMA/CA, it is possible for latter blocks to catch up or outpace the earlier one, which complicates blockchain forking problem. In view of this, we propose mining strategies to pause mining for reducing the forking probability, and a discard strategy to remove the forking blocks that already exist in CSMA/CA backoff procedure. Based on the proposed strategies, we design Block Access Control (BAC) approaches to effectively schedule block mining and transmitting for improving the performance of B-WLAN. Then, Markov chain models are presented to conduct performance analysis in B-WLAN. The results show that BAC approaches can help the network to achieve a high transaction throughput while improving block utilization and saving computational power. Meanwhile, the trade-off between transaction throughput and block utilization is demonstrated, which can act as a guidance for practical deployment of blockchain. [ABSTRACT FROM AUTHOR]

Today's field-programmable gate arrays (FPGAs) offer not only programmable acceleration capabilities but also include advanced features that are on-par with a mainstream processor platform. However, rather than being deployed as autonomous acceleration nodes, they are generally deployed as second-class citizens under the control of a standard processor platform. The configurable network protocol accelerator (COPA) framework enables FPGAs to support custom inline/lookaside accelerators and attach directly to a 100-Gb/s Ethernet network. The hardware component provides the necessary networking/accelerator infrastructure. The software component supports an open standard API that enables the integrated accelerators to be used with network communication by applications/middleware. COPA enables a truly distributed FPGA accelerator model and has been implemented on variants of Stratix10 FPGAs. The COPA framework along with example accelerator IPs has been validated with microbenchmarks as well as proxy client/server benchmarks and achieves full network bandwidth. [ABSTRACT FROM AUTHOR]

Real-world robot networks create hostile radio environments due to their highly dynamic communication topologies and stringent real-time transmission requirements. In this article, we propose improvements to contention-based networks that utilize inter-robot navigation information for safer robot motion control in dense multi-robot settings. Toward this end, we introduce a Crash Risk Prioritization (CRP) index, which is employed as the core metric in a scheme of dynamic beacon rate control. Key to our approach is a coupled evaluation setup that allows us to evaluate the impact of network-level changes on the safety of robot navigation. Our results demonstrate that the co-design and simulation of robotic control algorithms and network protocols provide key insights and metrics into the network-level requirements for V2V systems. These insights allow us to make informed conclusions about how such networks can be best served by emerging standards. [ABSTRACT FROM AUTHOR]

Amazon Web Services (AWS) took a fresh look at the network to provide consistently low latency required for supercomputing applications, while keeping the benefits of public cloud: scalability, elastic on-demand capacity, cost effectiveness, and fast adoption of newer CPUs and GPUs. We built a new network transport protocol, scalable reliable datagram (SRD), designed to utilize modern commodity multitenant datacenter networks (with a large number of network paths) while overcoming their limitations (load imbalance and inconsistent latency when unrelated flows collide). Instead of preserving packets order, SRD sends the packets over as many network paths as possible, while avoiding overloaded paths. To minimize jitter and to ensure the fastest response to network congestion fluctuations, SRD is implemented in the AWS custom Nitro networking card. SRD is used by HPC/ML frameworks on EC2 hosts via AWS elastic fabric adapter kernel-bypass interface. [ABSTRACT FROM AUTHOR]

Named Data Networking (NDN) architectural features, including multicast data delivery, stateful forwarding, and in-network data caching, have shown promise for applications such as video streaming and file sharing. However, collaborative applications, requiring multi-producer participation, introduce new NDN design challenges. in this article, we highlight these challenges in the context of the Network Time Protocol (NTP) and one of its most widely-used deployments for NTP server discovery, the NTP pool project. We discuss the design requirements for the support of NTP and NTP pool and present general directions for the design of a time synchronization protocol over NDN, called Named Data Networking Time Protocol (NDNTP). [ABSTRACT FROM AUTHOR]

Backscatter radio is an intriguing technology for Internet of Things applications, which enables ultra-low-power devices to communicate with each other. Most of the existing works on the combination of the backscatter communications and the “harvest-then-transfer” (HTT) protocol focus on the throughput maximization, yet the study on the energy efficiency (EE) maximization is still lacking. Driven by this observation, this paper studies the EE maximization for an RF-powered backscatter network with the HTT protocol. Multiple hybrid devices (HDs) can either use the backscatter mode by backscattering energy signals from the power beacon (PB) to the reader or use the HTT protocol to first harvest energy from the PB, and then to transmit data to the reader. The proposed scheme aims to optimize multiple parameters including PB's transmit power and time, HDs’ transmit power and time allocation between the backscatter mode and the HTT mode for maximizing the EE of all the HDs. An iterative algorithm is developed to find the optimal solution for the proposed resource allocation scheme. Simulation results demonstrate the superiority of the proposed scheme in terms of EE of all the HDs. [ABSTRACT FROM AUTHOR]

Load balancing in datacenter networks (DCNs) is an important and challenging task for datacenter managers. A number of sophisticated technologies have been proposed to improve load balancing performance in a complicated circumstance, i.e., with various traffic characteristics. Many approaches need a high cost to implement, such as changing switch hardware. The efficiency problem has not been well addressed. MPTCP was proposed as a low-cost approach to improve data transmission in DCNs, which uses subflows to balance workloads across multiple paths. However, current MPTCP is not satisfying, especially when there are rack-local flows or many-to-one short flows. In this article, we propose DCMPTCP to improve the efficacy of MPTCP. We gradually develop three mechanisms. First, DCMPTCP identifies rack-local traffic and eliminates unnecessary subflows to reduce the overhead. Second, DCMPTCP estimates flow length and establishes subflows in a smarter way. Third, DCMPTCP strengthens explicit congestion notification to improve the congestion control performance on inter-rack many-to-one short flows. We have implemented DCMPTCP in both the Linux kernel and ns-3 simulator. Our comprehensive testbed experiments and simulations show that DCMPTCP outperforms MPTCP in both 1 Gbps testbed, and 10 Gbps large-scale simulation network. [ABSTRACT FROM AUTHOR]

IEEE 1588, built on the classical two-way message exchange scheme, is a popular clock synchronization protocol for packet-switched networks. Due to the presence of random queuing delays in a packet-switched network, the joint recovery of the clock skew and offset from the timestamps of the exchanged synchronization packets can be treated as a statistical estimation problem. In this paper, we address the problem of clock skew and offset estimation for IEEE 1588 in the presence of possible unknown asymmetries between the deterministic path delays of the forward master-to-slave path and reverse slave-to-master path, which can result from incorrect modeling or cyber-attacks. First, we develop lower bounds on the mean square estimation error for a clock skew and offset estimation scheme for IEEE 1588 assuming the availability of multiple master-slave communication paths and complete knowledge of the probability density functions (pdf) describing the random queuing delays. Approximating the pdf of the random queuing delays by a mixture of Gaussian random variables, we then present a robust iterative clock skew and offset estimation scheme that employs the space alternating generalized expectation-maximization (SAGE) algorithm for learning all the unknown parameters. Numerical results indicate that the developed robust scheme exhibits a mean square estimation error close to the lower bounds. [ABSTRACT FROM AUTHOR]

Many optimization techniques for networking protocols take advantage of topological information to improve performance. Often, the topological information at the core of these techniques is a centrality metric such as the Betweenness Centrality (BC) index. BC is, in fact, a centrality metric with many well-known successful applications documented in the literature, from resource allocation to routing. To compute BC, however, each node must run a centralized algorithm and needs to have the global topological knowledge; such requirements limit the feasibility of optimization procedures based on BC. To overcome restrictions of this kind, we present a novel distributed algorithm that requires only local information to compute an alternative similar metric, called Load Centrality (LC). We present the new algorithm together with a proof of its convergence and the analysis of its time complexity. The proposed algorithm is general enough to be integrated with any distance vector (DV) routing protocol. In support of this claim, we provide an implementation on top of Babel, a real-world DV protocol. We use this implementation in an emulation framework to show how LC can be exploited to reduce Babel's convergence time upon node failure, without increasing control overhead. As a key step towards the adoption of centrality-based optimization for routing, we study how the algorithm can be incrementally introduced in a network running a DV routing protocol. We show that even when only a small fraction of nodes participate in the protocol, the algorithm accurately ranks nodes according to their centrality. [ABSTRACT FROM AUTHOR]

The high relying of electric vehicles on either in-vehicle or between-vehicle communications can cause big issues in the system. This paper is going to mainly address the cyberattack in electric vehicles and propose a secured and reliable intelligent framework to avoid hackers from penetration into the vehicles. The proposed model is constructed based on an improved support vector machine model for anomaly detection based on the controller area network bus protocol. In order to improve the capabilities of the model for fast malicious attack detection and avoidance, a new optimization algorithm based on social spider optimization algorithm is developed, which will reinforce the training process offline. Also, a two-stage modification method is proposed to increase the search ability of the algorithm and avoid premature convergence. Last but not least, the simulation results on the real datasets reveal the high performance, reliability, and security of the proposed model against denial-of-service hacking in the electric vehicles. [ABSTRACT FROM AUTHOR]

In this paper, we study the optimal power allocation for a radio frequency (RF)-powered cooperative network and propose energy-saving time switching relaying (ES-TSR) and energy-saving power splitting relaying (ES-PSR) protocols with an iterative energy-saving (ES) algorithm. In particular, we develop the analytical expressions of the channel capacity and the total energy consumption for the considered cooperative network. We formulate the system energy efficiency maximization problems and then provide the corresponding solutions by deriving the source's optimal transmit power in terms of energy fraction consumed with time switching (TS) factor and power splitting (PS) factor for the proposed ES-TSR and ES-PSR protocols, respectively, in each transmission block. From the past approaches, the optimal power allocation to maximize the system energy efficiency of the RF-powered cooperative networks has been studied under the assumption that the relay must utilize all of its harvested power in each transmission block. This work considers optimal power allocation to maximize the system energy efficiency for the case when the relay node can save energy for the next transmission block. Our simulation results show that the proposed ES-TSR and ES-PSR protocols outperformed the existing TS-based and PS-based relaying protocols with $\text{14.22}\%$ and $\text{8.4}\% $ , respectively, in paticular when the number of transmission blocks $\boldsymbol{L} = 10$. [ABSTRACT FROM AUTHOR]

A number of methods have been proposed for the response-time analysis (RTA) of controller area networks (CANs), which are the industry standard for in-vehicle network protocols. However, most of these methods are unsuitable for analyzing nonperiodically transmitted messages because they assume a constant transmission period for each message. Moreover, the calculated evaluation criteria are limited and comprise many over-pessimistic estimations, such as the worst-case response time (WCRT). To tackle these problems, this paper proposes an RTA method for CANs with randomly occurring messages, which replaces the constant transmission period with the average number of transmission instances per unit time. This approach finds the approximate probability distribution of the response time to any message in a CAN, providing a more general measure than the WCRT. To this end, a mathematical model based on M/G/1 queueing theory is developed. The model accurately emulates the behavior of nonperiodic CAN messages and enables RTA with minimal pessimistic estimations. When tested against the benchmarks, the proposed method accurately obtained response time distributions within several seconds to several tens of seconds. [ABSTRACT FROM AUTHOR]

In this paper, the performance of the cooperative cognitive radio network with the amplify-and-forward protocol is studied when the relay uses a nonlinear power amplifier (NLPA). Furthermore, taking the pulse shaping filter for the data signal into account, the power of the adjacent channel interference (ACI) to the primary users (PUs) caused by the spectral regrowth of the relay output signal is analytically calculated. Moreover, two compensation techniques are proposed which are implemented at the destination receiver to deal with the in-band nonlinear interference. The first technique is based on the calculation of the distorted signal constellation to enhance the performance of the demodulator. The second technique is feedforward compensation at the receiver. The bit error rate (BER) expressions for both techniques are presented. The ACI resulting from the spectral regrowth due to the relay NLPA is investigated by the simulation and numerical studies, and then, the BER performance degradation at the destination node and the performance improvement resulting from the proposed compensation methods are evaluated. Since the ACI confines the transmit power due to the interference power constraint of the PU, the achievable BER of the secondary user (SU) is studied. The simulation results show that the feedforward compensation technique has better BER performance than the modified constellation based approach. [ABSTRACT FROM AUTHOR]

The explosion of Internet of Things (IoT) applications makes the existing network structure insufficient because it is split by multiple non-cooperative operators, does not scale with the future development of IoT, and calls for novel networking concepts and protocols. The need for multi-operator IoT paradigms poses some unprecedented challenges, including trust considerations. To enable a multi-operator network without shared authentication, we propose a trustworthy grant-free IoT access protocol named Hash Access by leveraging a blockchain radio access network (B-RAN) architecture. B-RAN re-organizes multiple individual radio access networks into a joint multi-operator network based on a blockchain. B-RAN can establish trust among initially trustless operators and efficiently utilize resources across networks, matching and creating values for multiple participants. Furthermore, to mitigate the loss of network efficiency caused by selfish behavior among untrustworthy IoT devices, the proposed protocol can induce IoT devices to follow an access rule and control their data traffic. The proposed framework unifies the IoT access and the underlying B-RAN to reduce confirmation delays in traditional blockchains significantly. Numerical experiments illustrate the performance edge for the B-RAN-enabled Hash Access. [ABSTRACT FROM AUTHOR]

Coherent communications aim to support higher data rates and extended connectivity at lower power consumption compared with traditional point-to-point transmissions. The typical setting of coherent communication schemes is based on a single data stream with multiple transmitters and a single receiver. This paper studies the case of multiple concurrent data streams, each with multiple transmitters and multiple receivers, in self-organizing wireless networks. A distributed optimization solution based on joint network formation and beamforming is developed for coherent group communications in a network of nodes that need to communicate over long distances. This solution significantly improves the power gain for a single data stream and the signal-to-interference-ratio for multiple data streams compared to point-to-point communications. These gains are in turn translated to improvements in communication range, power efficiency, reliability, and throughput. In this multi-layer network optimization solution, nodes coordinate with each other in a distributed manner to form transmitter and receiver groups, and communicate with each other coherently over long distances. The coherent beamforming protocol is optimized for given transmitter and receiver groups, whereas the network formation protocol is optimized to determine these groups. By using single-antenna communication nodes, the proposed optimization solution provides a major gain in network communications and outperforms other benchmark combinations of beamforming and network formation protocols. [ABSTRACT FROM AUTHOR]

FlexRay offers high-speed reliable transmission in the vehicle domain. Thus, it is one of the most popular in-vehicle communication protocols for the applications that are safety-critical or applications with very low transmission time requirement. Due to the real-time constraint, the worst case end-to-end delay (EED) for such applications transmitting over a shared bus must be known. This paper addresses the problem of computation of EED for a given set of tasks with precedence constraint and corresponding messages, which are scheduled with slot multiplexing for event-triggered communication over the dynamic segment of FlexRay. First, computing precise delay has been shown to be an intractable problem. Subsequently, motivated by the intractability, an efficient estimation technique has been proposed to compute approximate EED. Unlike the common practice of considering the network in isolation, we present a comprehensive timing analysis, which considers the effects of task execution as well. Moreover, EED is allowed to be greater than interactivation time of task graph. The extensive simulation has been performed on the test cases generated with uniform as well as normal distribution. Note to Practitioners—In the past few decades, due to the large-scale use and sophistication of automotive electronic systems, various in-vehicle communication networks and protocols are also evolving. FlexRay is one such in-vehicle communication protocol, which provides the mechanism for the fault-tolerant high-speed communication over FlexRay bus. FlexRay is widely being employed for safety-critical applications in the automotive domain. For such applications, often the timing constraint is imposed with a bound on the worst case EED. Thus, timing properties of the designed network must be verified before applying it on the real domain such that the worst case EED for the propagation of an event at sensor end to actuator end is known. The proposed estimation technique can be used to compute approximate EED for an application scheduled with other applications over the dynamic segment of FlexRay. In addition, various guidelines for designing the network in order to reduce overestimation have also been presented. [ABSTRACT FROM AUTHOR]

A new random channel access framework, named as zigzag-division multiple access (ZDMA), is proposed for wireless networks with long and heterogeneous propagation delays to achieve system throughput significantly larger than 1. The key idea is to allow simultaneous transmissions at the transmitters and employ zigzag decoding at the receiver. After studying the zigzag decoding, we present three new random access protocols. Extensive numerical studies show that incorporating ZDMA in existing slotted Aloha and tree splitting protocols can significantly increase system throughput. The third protocol of greedy scheduling with ZDMA achieves the highest throughput performance. [ABSTRACT FROM AUTHOR]

IoT has evolved from an experimental to a backbone technology able to connect myriads of people, things, and services for a large range of businesses. At the same time, the emergence of SDN can ideally handle IoT challenges for elasticity, heterogeneity, and mobility, offering an architecture that abstracts decision making away from the data plane and providing a programmable network facility. Along these lines, we propose MINOS, a multi-protocol SDN platform for IoT that implements service awareness utilizing appropriate SDN abstractions and interfaces for logically centralized network control of diverse and resource-constrained IoT environments, two network protocols that are deployable and configurable on demand, and a GUI that provides a bespoke dashboard and a real-time visualization tool. Due to its components, MINOS enables experimentation with novel network control features and protocols that realize optimized routing over heterogeneous IoT nodes, application of real-time strategies as a response to dynamic network conditions, support of individual protocol configurations per node, and flexibility to accommodate new protocols and control algorithms. Our results demonstrate MINOS as an enabling platform for two protocols, CORAL-SDN and Adaptable-RPL, which, in comparison with the state-of-the-art IoT routing protocol RPL, improve the packet delivery ratio with relatively small control overhead. [ABSTRACT FROM AUTHOR]

This paper presents a protocol that enables an unlimited number of Wi-Fi users to position themselves within a meter-level accuracy and navigate indoors using time-delay-based Wi-Fi measurements. The proposed protocol, called collaborative time of arrival, is broadcast-based and relies on cooperation between the network sensors that support IEEE 802.11 fine-timing measurements (FTMs) capabilities, which are enabled in state-of-the-art Wi-Fi chipsets. The clients can estimate and track their position by passively listening to timing measurements that are exchanged between the FTM-sensors. The passive nature of the clients’ operation enables them to maintain their privacy by not exposing their presence to the network. This paper outlines the principles of the protocol and the mathematical background of the position estimation algorithms. Both theoretical analysis of the expected positioning accuracy, as well as real-life system performance examples, are provided. The protocol’s performance analysis is based on a publicly available database of real network measurements. [ABSTRACT FROM AUTHOR]

A natural basis for the detection of a wireless random reactive jammer (RRJ) is the perceived violation by the detector [typically located at the access point (AP)] of the carrier sensing protocol underpinning many wireless random access protocols (e.g., Wi-Fi). Specifically, when the wireless medium is perceived by a station to be busy, a carrier sensing compliant station will avoid transmission, while an RRJ station will often initiate transmission. However, hidden terminals (HTs), i.e., activity detected by the AP but not by the sensing station, complicate the use of carrier sensing as the basis for RRJ detection since they provide plausible deniability to a station suspected of being an RRJ. The RRJ has the dual objectives of avoiding detection and effectively disrupting communication, but there is an inherent performance tradeoff between these two objectives. In this paper, we capture the behavior of both the RRJ and the compliant stations via a parsimonious Markov chain model and pose the detection problem using the framework of the Markov chain hypothesis testing. Our analysis yields the receiver operating characteristic (ROC) of the detector and the optimized behavior of the RRJ. While there has been extensive work in the literature on jamming detection, our innovation lies in leveraging carrier sensing as a natural and effective basis for detection. [ABSTRACT FROM AUTHOR]

Controller area network (CAN) is the most widely adopted network protocol in vehicle communication systems. The intermittent connection (IC) fault, a random cable connectivity problem with short durations, occurring in the CAN network may result in system performance degradation and system level failures in severe cases. Therefore, the health management of CAN-based networked systems demands effective detection and accurate localization of the IC fault. However, the diagnosis of IC fault in CAN network has not been fully exploited. This paper proposes a novel tree-based IC fault diagnosis method to identify the various IC fault locations in the CAN network. First, the error event pairs for network nodes are defined by analyzing the data-link layer information upon each error. Then, the domains of error event pairs and the information cost of IC faults included in the domains are derived. Finally, a tree-based minimal cost diagnosis algorithm is proposed to find the locations of the IC faults. Laboratory testbed is constructed and the case studies are conducted to demonstrate the performance of the proposed method. The results show that IC fault identified by the proposed method agree well with the case study setups. [ABSTRACT FROM AUTHOR]

This paper proposes an analytical model to investigate the performance of periodical broadcast of safety messages in vehicular ad hoc networks (VANETs), regarding a hybrid medium access control (MAC) protocol, called NC-PNC MAC. We first examine the percent of vehicles involved in subcarrier collisions during a random orthogonal frequency-division multiple access scheme, and then theoretically analyze the total number of transmissions and the packet delivery ratio (PDR) during one dissemination period. Based upon the analysis, this paper not only reveals how the subcarrier collision probability influences the PDR performance, but mathematically obtains the maximum PDR. To confirm the results, by adjusting a pivotal parameter of the MAC protocol, the PDR performance for basic safety message broadcast in VANETs can be enhanced by 10% to 30% under the constraint of the delivery latency. [ABSTRACT FROM AUTHOR]

Extending an Internet subnet by connecting resource-constrained nodes (e.g., embedded sensors and actuators) over multiple wireless hops is necessary to support the future Internet of Things (IoT). RPL, the IPv6 routing standard for low-power and lossy networks, tried to achieve this goal but has not seen wide adoption in practice. As an alternative, Thread is a recently standardized low-power network protocol for IoT, driven by the Thread group, an industry consortium led by Google/Nest. We provide a comparative analysis of the technical aspects of RPL and Thread based on their specifications, explaining why using Thread, as opposed to RPL, may make sense for the future Internet. Specifically, the fundamental differences between RPL and Thread are their respective scopes and multihop network architectures, which result in Thread's unique design and advantages over RPL. Lastly, we evaluate Thread in an indoor multihop wireless testbed using OpenThread, an official open source implementation of Thread. This work serves as the first analysis of the Thread protocol in academia. [ABSTRACT FROM AUTHOR]

We describe a new vision of joint computation and communication resource management that goes beyond the end-to-end and client-server model of the current Internet. Enabled by a growing trend toward embedding processing and networking capabilities into "smart" network nodes and devices, for example, smartphones, watches, appliances, and automobiles, Dispersed Computing describes a new resource-centric architecture that leverages the diversity of networked computation points within the network, and the heterogeneity of network links and protocol stacks that connect them. We describe this new, resource-centric architecture as an evolution of both fog/edge networking and active networks. We illustrate the fundamental principles and the advantages over the current Internet architecture, and highlight several commercial use cases enabled by a dispersed computing architecture. [ABSTRACT FROM AUTHOR]

For a second generation secure telephone system, Howard Rosenblum in 1967 proposed and patented a key distribution system that he called Bellfield. 2 When in the 1960s the NSA developed a secure telephone system these requirements presented a problem: since anyone with a phone capable of encryptionmightplaceacalltoanyothersuchphone, it seemed that there had to be an advance arrangement to share a unique encryption key between every potential pair of telephones. Thus, cryptographic communication requires advance planning to choose encryption and decryption keys and to distribute those keys to the sender and receiver using a secure communication method. The remainder of this discussion assumes use of symmetric encryption, which means that the encryption and decryption keys are either identical or derivable one from the other, so the secure communication of the keys must assure bothconfidentialityandintegrity. [Extracted from the article]

The increasing growth of Internet of Things (IoT) applications induces the need for easy integration of third-party peripherals, which is restricted in present IoT devices. In this paper, we present a novel plug-and-play (PnP) solution for the above stated problem. The proposed PnP solution, named SensPnP, is the combination of embedded hardware and firmware that has the capability of integrating third-party embedded sensors with the IoT devices without any prior information about the sensors and the Internet. We present an architecture of a PnP-enabled IoT device, which supports heterogeneous embedded peripheral communication protocols. A novel embedded protocol detection approach for enabling seamless integration of sensor with IoT device is proposed. To enable sensor communication, we propose an algorithm for automatic driver management of the connected sensor with an IoT device. This is achieved through a low-cost and low power switching and identification hardware with a light-weight identification and driver management firmware stack. To show the effectiveness of the proposed solution, we practically implemented a prototype in a real test-bed. The analysis of the PnP time, protocol identification time, the memory footprint, lifetime, and overall cost of the proposed PnP solution under different operating conditions establishes superiority of its circuitry and firmware. Experimental results show that SensPnP requires minimal memory footprint, reduced energy consumption, and reduced PnP time compared to the existing solutions. Additionally, the overall cost analysis shows that the cost of SensPnP is noticeably less compared to existing solutions. Thus, the cost-efficiency of SensPnP makes it more acceptable to the consumers when compared with existing solutions. [ABSTRACT FROM AUTHOR]

Wind energy is one of the most attractive and one of the fastest growing sources of green energy in the world. With the expansion of wind parks, there is a growing need for an efficient coordination of the diverse energy production systems, as well as a tighter coupling between the production and the consumer side of the grid. Current grid operators have unnecessarily high costs due to the lack of an integrated management system toward a diverse set of proprietary network protocols, complex and error prone operation of the networks, as well as rigid security mechanisms. Network softwarization concepts, that is, SDN and NFV, offer great potential for reducing capital and operational expenditures by providing simplified network management and automated control. Recent works have demonstrated the feasibility of achieving stringent industrial-grade quality of service and fine grain security control with SDN and NFV. In this article, we provide an insight into wind park communication network requirements, analyze the technological benefits of the network softwarization, and demonstrate the economic profits in a case study of a typical Northwestern Europe wind park. [ABSTRACT FROM AUTHOR]

Multi-channel cognitive radio ad hoc networks (CRAHNs) and information-centric networking (ICN) will be indispensable for enabling envisioned multimedia-based smart services within the umbrella of smart cities. Cognitive radios enable the efficient and opportunistic use of spectrum bands by using vacant licensed channels, whereas information- centric networking improves content distribution by decoupling producers and consumers. In this work, we discuss the design of information-centric cognitive radio-based networking for multimedia- based applications in smart cities. We examine the potential of the joint design of CRAHNs and ICN, and thoroughly review fundamental aspects and challenges of CR and ICN for smart cities. Subsequently, we qualitatively study the capability of information-centric cognitive radio-based networking for improving network connectivity, content search and distribution, reliability and confined delay in smart city safety and infotainment-based applications. Finally, we highlight future research directions for the design of protocols for this envisioned network that will support smart cities. [ABSTRACT FROM AUTHOR]

The number of IoT devices has been growing significantly, and mobile network traffic is also increasing explosively. In order to meet the human desire to explore unknown areas, edgeless communications have always been one of the directions for the development of wireless networks. H-STIN is a promising solution to face the problem of large bandwidth requirement, massive machine type communication, and edgeless communication requirements. However, it is difficult to integrate communication protocols, routing problems, and resource allocation in the large-scale and heterogeneous network architecture. Therefore, this article proposes a potential H-STIN architecture based on the development trends of the Internet of Things, mobile networks, and satellite networks. Since TN has adequate computation resource and routing architecture, the backbone network is given to support an entire network, and AS is adopted to achieve regional self-optimization. The SSTIS is composed of the perception layer, the cognition layer, and the intelligence layer. It integrates IoT, SDN, and network functions virtualization technologies to achieve self-monitoring, crisis forecasting, and optimal control. Finally, the promising technical challenge, including integrated route planning and large-scale resource allocation, is given. [ABSTRACT FROM AUTHOR]

Existing CoAP primarily focuses on communication (i.e., client/server-based request/response interaction) between constrained devices in a constrained network. Constrained networks may have large latencies and constrained devices may not be able to respond in a timely manner. Therefore, incorporating delay awareness in the CoAP protocol may prove beneficial for communications between devices. This article presents a new method to support a delay-aware CoAP messaging model, where a Delay- Indicator is proposed to be contained in messages to reflect delay tolerance information. Furthermore, the DelayIndicator can be leveraged by CoAP Clients and CoAP Servers to improve their operations of entering sleep mode to save energy while not violating delay tolerances. With this new enabler, a timeout mechanism for CoAP Responses is put forward to enhance CoAP performance. Simulation results show that incorporating delay awareness in CoAP significantly improves messaging performance. [ABSTRACT FROM AUTHOR]

Multimedia cloud computing has appeared as a very attractive environment for the business world in terms of providing cost-effective services with a minimum of entry costs and infrastructure requirements. There are some architecture proposals in the related literature, but there is no multimedia cloud computing architecture with hybrid features specifically designed for mobile devices. In this article, we propose a new multimedia hybrid cloud computing architecture and protocol. It merges existing private and public clouds and combines IaaS, SaaS and SECaaS cloud computing models in order to find a common platform to deliver real time traffic from heterogeneous multimedia and social networks for mobile users. The developed protocol provides suitable levels of QoS, while providing a secure and trusted cloud environment. [ABSTRACT FROM AUTHOR]

Fuel utilization efficiency and cost reduction are two major goals in designing in-vehicle networks. Aiming to address these two issues, we investigate in-vehicle networking protocols from both wired and wireless perspectives by first presenting representative solutions in each area, then identifying the challenges to current solutions, and finally advocating the use of the automotive Ethernet. Also, we propose a priority-based scheduler for the automotive Ethernet. Our preliminary experiments show that the proposed scheduler is effective and flexible, and thus is applicable to next-generation in-vehicle networks. We hope that further studies in this area can be inspired by our work and will be forthcoming in years to come. [ABSTRACT FROM AUTHOR]

Dynamic adaptive streaming over HTTP (DASH) has recently been widely deployed in the Internet and adopted in the industry. It, however, does not impose any adaptation logic for selecting the quality of video segments requested by clients and suffers from lackluster performance with respect to a number of desirable properties: efficiency, stability, and fairness when multiple players compete for a bottleneck link. In this paper, we propose a throughput-friendly DASH rate control scheme for video streaming with multiple clients over DASH to well balance the tradeoffs among efficiency, stability, and fairness. The core idea behind guaranteeing fairness and high efficiency (bandwidth utilization) is to avoid OFF periods during the downloading process for all clients, i.e., the bandwidth is in perfect-subscription or over-subscription with bandwidth utilization approach to 100%. We also propose a dual-threshold buffer model to solve the instability problem caused by the above idea. As a result, by integrating these novel components, we also propose a probability-driven rate adaption logic taking into account several key factors that most influence visual quality, including buffer occupancy, video playback quality, video bit-rate switching frequency and amplitude, to guarantee high-quality video streaming. Our experiments evidently demonstrate the superior performance of the proposed method. [ABSTRACT FROM AUTHOR]