Search

Vehicle Ad-hoc network (VANET) can provide technical support and solutions for the construction of intelligent and efficient transportation systems, and the routing protocol directly affects the efficiency of VANET. The rapid movement of nodes and uneven density distribution affect the routing stability and data transmission efficiency in VANET. To improve the local optimality and routing loops of the path-aware greedy perimeter stateless routing protocol (PA-GPSR) in urban sparse networks, a weight-based path-aware greedy perimeter stateless routing protocol (W-PAGPSR) is proposed. The protocol is divided into two stages. Firstly, in the routing establishment stage, the node distance, reliable node density, cumulative communication duration, and node movement direction are integrated to indicate the communication reliability of the node, and the next hop node is selected using the weight greedy forwarding strategy to achieve reliable transmission of data packets. Secondly, in the routing maintenance stage, based on the data packet delivery angle and reliable node density, the next hop node is selected for forwarding using the weight perimeter forwarding strategy to achieve routing repair. The simulation results show that compared to the greedy peripheral stateless routing protocol (GPSR), for the maximum distance–minimum angle greedy peripheral stateless routing (MM-GPSR) and PA-GPSR protocols, the packet loss rate of the protocol is reduced by an average of 24.47%, 25.02%, and 14.12%, respectively; the average end-to-end delay is reduced by an average of 48.34%, 79.96%, and 21.45%, respectively; and the network throughput is increased by an average of 47.68%, 58.39%, and 20.33%, respectively. This protocol improves network throughput while reducing the average end-to-end delay and packet loss rate. [ABSTRACT FROM AUTHOR]

With the dense deployment of basic service set (BSS) in the next generation Wireless Local Access Network (WLAN). The overlapping coverage of multiple BSSs leads to intensified contention conflicts, low efficiency of buffer state reports (BSR) collection and a sharp decline in system throughput. To solve this problem, this paper proposes an access point (AP) cooperation based multi-BSS multi-user full duplex multiple access protocol (CMMFD). Firstly, access control (AC) divides the STAs in the cooperative network area into overlapping STA and non-overlapping STA. A bi-level channel resource allocation algorithm is designed. The first level is channel resource allocation in the collection stage of BSR and inter-node interference information (BI), and the second level is channel resource allocation in full duplex data transmission. Secondly, a protocol framework for parallel BI information collection of cooperative APs is designed. AC schedules cooperative APs to send trigger frame at the same time, and triggers STAs in each BSS to report BI information on the assigned channel resource with p -probability access mode. Finally, AP forwards the collected BI information to AC, and AC assigns the STAs in the multi-BSS to perform multi-user full-duplex transmission on the resource unit (RU). Theoretical analysis gives the closed form expressions of the mean number of STAs successfully collected by AC in the cooperation area and saturated network throughput. Simulation results show that compared with MU-FuPlex and EnFD-OMAX protocol, CMMFD protocol improves the network throughput by 29.6% and 31.2% respectively. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is a system of machines, computing devices, electronic equipment, and different sensors. It forms a network, where the transmission of device-related data can be accomplished. The devices in the IoT are connected to each other through wireless links and form ad-hoc networks. In IoT based applications, the lifetime of the communicating nodes is a greater concern. The network lifetime can be maximized by introducing energy efficient data transmission in the network. Therefore, a traffic and delay-aware energy-efficient routing (TADEER) protocol for IoT-based networks are proposed in this work. The proposed technique assigns delay for transmitting data based on the criticality level of data and traffic rate at the forwarding nodes. Fixing delays for data transmission helps to avoid unnecessary transmissions. The route selection process is implemented using an optimization algorithm. A Fuzzy logic (FL) based biogeography-based optimization (BBO) algorithm is presented in this work. Thus, the number of data transmission and energy consumption can be reduced. The performance of the proposed method is evaluated by analyzing transmission delay, network lifetime, and energy consumption. By comparing the simulation results to the existing methods TEAR and ETASA, the simulation results are validated. [ABSTRACT FROM AUTHOR]

Since several Internet of Things (IoT) applications have been widely deployed on unstable wireless networks, such as the Delay Tolerant Network (DTN), data communication efficiency in DTN remains a challenge for IoT applications. Vehicular Delay Tolerant Network (VDTN) has become one of DTN's potential applications, in which the network experiences connectivity interruption due to the lack of an end-to-end relay route. VDTNs focus on node cooperation to achieve this goal. As a result, it is essential to ensure that almost all network nodes adopt the protocol to preserve network performance. This is a challenging task since nodes may diverge from the basic protocol to optimize their effectiveness. This article presents an Efficient Monitoring System (EMS) to detect and respond to just selfish nodes to minimize their entire network and data communication efficacy. The scheme is based on a network-wide cooperative sharing of node reputation. It is also necessary to increase overall network efficiency by tracking selfish nodes. The NS-2 simulator is used to run this experimental setup. Simulation results indicate that the proposed scheme performs better in terms of probability of package delivery, package delivery delay, energy consumption, and amount of packet drops. For 80% selfish nodes in the network, the packet delivery of EMS is 37% and 31% better than SOS and IPS. Similarly, the average delivery delay of EMS is 22% and 18% lower than SOS and IPS when 80% selfish nodes are incorporated in the network. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) are considerably used for various environmental sensing applications. The architecture and internal specifications of WSNs have been chosen based on the requirements of particular applications. On this basis, WSNs consist of resource (energy and memory)-limited wireless sensor nodes. WSNs initiate data communication from source to destination via physical layer management principles, channel slot scheduling principles (time division multiple access), wireless medium access control (WMAC) protocols, wireless routing protocols and application protocols. In this environment, the development of WMAC principles, routing protocols and channel allotment schemes play crucial roles in network communication phases. Consequently, these layering functions consume more energy at each sensor node, which leads to minimal network lifetime. Even though the channel management schemes, medium control protocols and routing protocols are functionally suitable, the excessive energy consumption affects the overall network performance. In this situation, energy optimization algorithms are advised to minimize the resource wastage of WSNs during regular operations (medium control and routing process). Many research works struggle to identify the optimal energy-efficient load balancing strategies to improve WSN functions. With this in mind, the proposed article has conducted a detailed literature review and notable experimental comparisons on energy-efficient MAC protocols, channel scheduling policies and energy-efficient routing protocols. To an extent, the detailed analysis over these wireless network operations helps to understand the benefits and limitations of recent research works. In the experimental section of this article, eight existing techniques are evaluated under energy optimization strategies (WMAC, channel allocation, sleep/wake protocols, integrated routing and WMAC policies, balanced routing and cooperative routing). The proposed review and the classified technical observations collected from notable recent works have been recognized as crucial contributions. The results infer the suggestions for feasible WSN communication strategies with optimal channel management policies and routing policies. Notably, the simulation results show that cross-layer or multi-layer energy optimization policies perform better than homogeneous energy optimization models. [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]

Filtered Smith predictors are well established for controlling linear plants with constant time delays. Apart from this classical application scenario, they are also employed within networked control loops, where the measurements are sent in separate packets over transmission channels that are subject to time-varying delays. Consequently, classical tools for the stability analysis, e.g., for time delay systems, have to be extended to facilitate an explicit consideration of network-induced effects such as packet skipping and disordering of sent packets. The present paper illustrates that the time-varying delays and, particularly important, the packetized character of the transmissions have to be explicitly taken into account for the stability analysis. Three network protocols, which use different packet selection and hold mechanisms, are considered to state criteria for the robust stability of the networked feedback loops with filtered Smith predictors. They are based on the small gain theorem and allow a computationally inexpensive way to check stability for the case with uncertain plant models and bounded time-varying packet delays in the communication channels. • Filtered Smith predictor for packet-based networked systems. • Communication network with bounded and time-varying packet delays. • Three different network protocols (different packet skipping and hold mechanisms). • Easy-to-use stability analysis for uncertain plants and time-varying packet delays. [ABSTRACT FROM AUTHOR]

This article is concerned with the consensus‐based distributed filtering problem for a class of general nonlinear systems over sensor networks with communication protocols. In order to avoid data collisions, the stochastic protocol and the Round‐Robin protocol are respectively introduced to schedule the data transmission between each node and its neighboring ones. A consensus‐based unscented Kalman filtering (UKF) algorithm is developed for the purpose of estimating the system states over sensor networks subject to communication protocols. Moreover, the exponential boundedness of estimation error in mean square is proved for the proposed algorithm. Finally, compared with the extended Kalman filtering, an experimental simulation example is provided to validate the effectiveness of the consensus‐based UKF algorithm. [ABSTRACT FROM AUTHOR]

Today, the wireless sensor network (WSN) plays an important role in our daily life. In addition, it is used in many applications such as military, medical, greenhouse, and transport. Due to the sending data between its nodes or to the base station requires a connection link, the sensor nodes can be exposed to the many attacks that exploit the weaknesses of the network. One of the most important types of these attacks is the denial of service (DoS). DoS attack exhausts the system's resources that lead the system to be out of service. In this paper, a cyber-security algorithm is proposed for physical level of WSN that adopts message queuing telemetry transport (MQTT) protocol for data transmission and networking. This algorithm predicts the DoS attacks at the first time of happening to be isolated from the WSN. It includes three stages of detecting the attack, predicting the effects of this attack and preventing the attacks by excluding the predicted nodes from the WSN. We applied a type of DoS attack that is a DoS injection attack (DoSIA) on the network protocol. The proposed algorithm is tested by adopting three case studies to cover the most common cases of attacks. The experiment results show the superior of the proposed algorithm in detecting and solving the cyber-attacks. [ABSTRACT FROM AUTHOR]

Upgraded network technology presents an advanced technological platform for telecare medicine information systems (TMIS) for patients. However, TMIS generally suffers various attacks since the information being shared through the insecure channel. Recently, many authentication techniques have been proposed relying on the chaotic map. However, many of these designs are not secure against the known attacks. In spite of the fact that some of the constructions attain low computation overhead, they cannot establish an anonymous communication and many of them fail to ensure forward secrecy. In this work, our aim is to present authentication and key agreement protocol for TMIS utilizing a chaotic map to achieve both security and efficiency. The underlying security assumptions are chaotic theory assumptions. This scheme supports forward secrecy and a secure session is established with just two messages of exchange. Moreover, we present a comparative analysis of related authentication techniques. [ABSTRACT FROM AUTHOR]

In the networks, a transport layer is responsible for reliable data with guaranteed Quality of Service. A Modified‐QUIC protocol provides improved throughput and reduced latency of the network. This work proposes a modification in handshaking mechanism for QUIC protocol to minimize overhead due to control signals and time required to update the congestion‐window size. This modification fine‐tunes the window update mechanism with the acknowledgment frame, which results in a smooth variation in the congestion‐window size. This leads to the control congestion by regulating traffic in the network. In the proposed mechanism, unnecessary time out events are avoided by updating the congestion‐window on receipt of the acknowledgment frame. This work has been carried out using two different testbed setups to verify the transport layer and a browser network performance. It has been observed that a Modified‐QUIC protocol is easy to deploy, improves the throughput and data rate by 35% and 3.43%, respectively, over the QUIC protocol. The average fairness index is increased with a file size and for the long live traffic. [ABSTRACT FROM AUTHOR]

Multi-channel ad hoc networks are promising technology to alleviate the spectrum scarcity in dense networks. The main challenge for channel access in distributed multi-channel ad hoc networks is channel synchronization and competition with neither common control channel nor dedicated control transceiver. In this paper, a Tight Synchronized MAC protocol with distributed synchronization and competition process without any dedicated control channel is proposed. The protocol uses a simple handshaking mechanism to create a channel table for each node, which contains its neighbors and channels' status. By this, any node knows the priority of its channels and also the priority of neighbors' channels. By assigning priorities, a sender node starts synchronization. If sender and receiver nodes have a common channel, the proposed method finds it directly or indirectly using the common neighbor mechanism. The other feature of the proposed scheme is using a fair preemptive data transmission phase, which reduces the number of switchings along data transmission. The fair preemptive mechanism is achieved by an analytical solution to estimate the number of competing nodes and thus, estimates the number of assigned data slots. Simulation results show the performance improvements in terms of synchronization delay and packet delivery ratio over HMMAC and MSRMMAC protocols. [ABSTRACT FROM AUTHOR]

In recent years, vehicle networks require high bandwidth due to the increasing complexity of electronic control devices for vehicles due to the demand for advanced driving aids, infotainment and V2X communication. Therefore, Ethernet protocol was introduced and vehicle gateway system was newly introduced in vehicle system. The vehicle gateway system provides an interface for continuously connecting and exchanging vehicle data in different communication environments between the Controller Area Network (CAN) protocol and the Ethernet network protocol. There are two types of data exchange in the vehicle gateway. These are direct routing and indirect routing. Vehicle gateways are connected to external networks, which can lead to security vulnerabilities. So it needs security function to ensure message integrity. Recently, vehicle manufacturers have introduced gateway systems with security features that operate to verify the integrity of messages using cipher-based message authentication codes (CMAC). But applying security functions to a gateway system introduces delays in performing security functions. Therefore, in this paper, to design stable and efficient the vehicle gateway system with security function, we have tested and evaluated the latency time that can occur according to the routing methods which are direct routing and indirect routing. [ABSTRACT FROM AUTHOR]

In recent years, vehicle networks require high bandwidth due to the increasing complexity of electronic control devices for vehicles due to the demand for advanced driving aids, infotainment and V2X communication. Therefore, Ethernet protocol was introduced and vehicle gateway system was newly introduced in vehicle system. The vehicle gateway system provides an interface for continuously connecting and exchanging vehicle data in different communication environments between the Controller Area Network (CAN) protocol and the Ethernet network protocol. There are two types of data exchange in the vehicle gateway. These are direct routing and indirect routing. Vehicle gateways are connected to external networks, which can lead to security vulnerabilities. So it needs security function to ensure message integrity. Recently, vehicle manufacturers have introduced gateway systems with security features that operate to verify the integrity of messages using cipher-based message authentication codes (CMAC). But applying security functions to a gateway system introduces delays in performing security functions. Therefore, in this paper, to design stable and efficient the vehicle gateway system with security function, we have tested and evaluated the latency time that can occur according to the routing methods which are direct routing and indirect routing. [ABSTRACT FROM AUTHOR]

Domain knowledge: Today, Wireless Sensor Network (WSN) is widely used for general purposes. With the propagation of the Internet of Things (IoT), security issues arise wherever the healthcare devices are used exclusively for data transfer protocols. These network protocols are easily susceptible to attack. Although it is problematic to save sensing information from the body sensors, the loss of signal messages will often occur in an IoT environment. Thus security is a supreme requirement in health care applications, especially in the case of patient privacy. Methodology: In this paper, an IoT health care communication system is designed to implement the integration using CoAP based Secure-aware Mobility Management Protocol (CoSMP) in Wireless Body Area Network (WBAN) based IoT environment. The proposed protocol is extremely effective to secure the sensing information of the device node wherever they are moving and additionally, it is accustomed to offer secure data transmission between the node and web client. Our protocol establishes a pairwise key between the networks according to an exact algorithm, namely Advanced Encryption Standard Cipher Feedback Message Authentication Code (AES-CFMAC) algorithm, and handover operation could be authenticated by Elliptic Curve Digital Signature Algorithm (ECDSA). Numerical analysis and performance result imposes the proposed scheme is simulated in terms of network delay and handover delay. Result: Experimental results depict that the proposed protocol has been compared with the previous protocol in terms of security and mobility management. Hence, the numerical result would be evaluated based on the measures of Total Transmission Delay (TTD) on the variation of wireless link delay, sensor node delay, link failure probability delay, hop count between the gateway and WMMS in the network delay with the low delay of 303.55, 1.6, 700 and 80 in ms respectively and also performance measures of Handover Delay (HD) achieves 1212.5, 1.212, 49.46 and 1453.8 in ms respectively. The percentage in terms of using performance measures of TTD and HD is compared between proposed and existing schemes resulted in (COMP = 0.3632%, COMP-G = 0.2712 % and COSMP = 0.2532%) and (COMP = 0.3188%, COMP-G = 0.2421 % and COSMP = 0.2133%) respectively. [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]

Leach (low energy adaptive clustering hierarchy) algorithm is a self-clustering topology algorithm. Its execution process is cyclical. Each cycle is divided into two phases: cluster building phase and stable data communication phase. In the stage of cluster building, the adjacent nodes cluster dynamically and randomly generate cluster heads. In the data communication phase, the nodes in the cluster send the data to the cluster head, and the cluster head performs data fusion and sends the results to the aggregation node. Because the cluster head needs to complete data fusion, communication with the convergence node and other works, the energy consumption is large. Leach algorithm can ensure that each node acts as cluster head with equal probability, so that the nodes in the network consume energy relatively evenly. The basic idea of Leach algorithm is to randomly select cluster head nodes in a circular way. It evenly distributes the energy load of the whole network to each sensor node in the network. It can reduce network energy consumption and improve network life cycle. Leach repeatedly performs cluster refactoring during its operation. This paper studies the parameter detection of wireless sensor network based on Leach algorithm on the on-chip embedded debugging system. Because the classical low-power adaptive clustering layered protocol (Leach) has the problem of energy imbalance and short node life cycle, this paper uses embedded debugging technology based on Leach algorithm and the residual energy and position of nodes in wireless sensor networks were tested for research. This Leach algorithm uses the concept of wheel. Each round consists of two phases: initialization and stabilization. In the initialization stage, each node generates a random number between 0 and 1. If the random number generated by a node is less than the set threshold T (n), the node publishes a message that it is a cluster head. Through the research on the parameter detection, the simulation results show that the research in this paper has good feasibility and rationality. [ABSTRACT FROM AUTHOR]

The utilization of wireless sensor networks (WSNs) is proliferating in our daily life. It depends on the environmental monitoring such as weather tracking, battled field, etc. However, the main challenge of WSNs is energy management. Generally, traditional nodes of the sensor network were powered by non-rechargeable batteries with limited energy capacity. The alternative solution has been discovered to resolve the limitation of the sensor battery called energy harvesting (EH). EH offers effective and an alternative solution to recharge the battery of the sensor node. It assists with the environment, and EH technique can be possible different kinds such as solar, wind, thermal and mechanical. In this paper, we propose a novel energy harvesting clustering protocol (NEHCP). The NEHCP is based on the hierarchical clustering routing algorithm, and this protocol uses solar EH. The collection of information from the sensor nodes is sent to the base station through the cluster head. The NEHCP algorithm is categorized into three sections, such as the initial phase, set-up phase and data transmission phase. Moreover, the unique feature of EH-WSNs is giving more efficient result in term of network lifetime. The simulation part of this method shows a strong ability to balance energy consumption and increases the network efficiency for the EH-WSNs. [ABSTRACT FROM AUTHOR]

Bearing-based hunting protocols commonly adopt a leaderless consensus method, which requests an entire state of the target for each agent and ignores the necessity of collision avoidance. We investigate a hunting problem of multi-quadrotor systems with hybrid bearing protocols, where the quadrotor systems are divided into master and slave groups for reducing the onboard loads and collision avoidance. The masters obtain the entire state of the target, whose hybrid protocols are based on the displacement and bearing constraints to maintain formation and to avoid the collision in the hunting process. However, the slaves' protocols merely depend on the part state of the masters to reduce loads of data transmission. We also investigate the feasibility of receiving the bearing state from machine vision. The simulation results are given to illustrate the effectiveness of the proposed hybrid bearing protocols. [ABSTRACT FROM AUTHOR]

In this paper, the distributed set-membership filtering problem is investigated for general nonlinear systems subject to Round-Robin and stochastic communication protocols over sensor networks. The considered disturbances are assumed to be unknown but bounded within certain known ellipsoidal regions. Two types of frequently used protocols, i.e., the Round-Robin and stochastic communication protocols are adopted separately to regulate the data transmission among sensor nodes. According to the Round-Robin protocol, each node is able to receive information from only one of its neighboring nodes in a circular order at each time step, whereas the stochastic communication protocol allows each node randomly receive the information sent from one of the neighboring nodes. By resorting to the recursive linear matrix inequalities approach, sufficient conditions are established for the existence of the desired distributed filter, guaranteeing that the state estimates are constrained within certain pre-determined ellipsoidal regions at each time step. Then two optimization problems aiming to minimize the ellipsoids (in the sense of matrix trace) are put forward to seek the locally optimal filtering performance. Finally, simulation examples are given to illustrate the effectiveness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

As the VoIP steganographic methods provide a low capacity covert channel for data transmission, an efficient and real-time data transmission protocol over this channel is required which provides reliability with minimum bandwidth usage. This paper proposes a micro-protocol for data embedding over covert storage channels or covert hybrid channels developed by steganographic methods where real-time transport protocol (RTP) is their underlying protocol. This micro-protocol applies an improved Go-Back-N mechanism which exploits some RTP header fields and error correction codes to retain maximum covert channel capacity while providing reliability. The bandwidth usage and the performance of the proposed micro-protocol are analyzed. The analyses indicate that the performance depends on the network conditions, the underlying steganographic method, the error correction code and the adjustable parameters of the micro-protocol. Therefore, a genetic algorithm is devised to obtain the optimal values of the adjustable micro-protocol parameters. The impact of network conditions, the underlying steganographic method and the error correction code on the performance are assessed through simulations. The performance of this micro-protocol is compared to an existing method named ReLACK where this micro-protocol outperforms its counterpart. [ABSTRACT FROM AUTHOR]

Summary: This paper investigates the strictly dissipative stabilization problem for multiple‐memory Markov jump systems with network communication protocol. Firstly, for reducing data transmission, we put forward a novel mode‐dependent event‐triggered communication scheme based on aperiodically sampled data. Secondly, a Markov jump system with general transition rates is considered to make the result more applicable, where the transition rates of some jumping modes allow to be completely known, or partially known, or even completely unknown. Thirdly, a less restrictive Lyapunov‐Krasovskii functional, which is only required to be positive definite at end points of each subinterval of the holding intervals, is first introduced for event‐triggered control issue. Based on the above methods, a sufficient condition with less conservatism is obtained to ensure the stochastic stability and dissipativity of the resulting closed‐loop system. Meanwhile, an explicit design method of the desired controller is achieved. Finally, two numerical examples are presented to demonstrate the effectiveness and advantage of the proposed method. [ABSTRACT FROM AUTHOR]

As one of the most important convergence layer (CL) protocol for delay/disruption-tolerant networking (DTN), Licklider transmission protocol (LTP) is designed for deep space communications, but it has rarely been considered for near earth applications. In this paper, LTP is proposed instead of TCP as CL with Bundle protocol (BP) for future application in GEO-relayed space networks (GRSN). Analytical models are built to estimate the file delivery time of LTP in GRSN. Experiments are also conducted on our computer based testbed in emulation of the basic scenarios during data transmission from LEO satellite to a ground station in GRSN. The results show that in transmission efficiency BP with LTPCL outperforms other protocols, such as BP with TCPCL, direct terrestrial TCP (TCP Cubic) and TCP variants (TCP Hybla) for space segments in most scenarios. It could be envisioned that DTN with LTPCL for space segment is currently the best choice for future GEO-relayed space internetworking. Moreover, performance of two different networking schemes,i.e. the on-board DTN routers and the bent-pipe relays are compared. It is observed that bent-pipe relays outperform the on-board DTN routers scheme when the channel condition is good, while the on-board DTN routers scheme performs better with high data loss ratio. [ABSTRACT FROM AUTHOR]

The advancement of precision medicine requires new methods to coordinate and deliver genetic data from heterogeneous sources to physicians and patients. The eMERGE III Network enrolled >25,000 participants from biobank and prospective cohorts of predominantly healthy individuals for clinical genetic testing to determine clinically actionable findings. The network developed protocols linking together the 11 participant collection sites and 2 clinical genetic testing laboratories. DNA capture panels targeting 109 genes were used for testing of DNA and sample collection, data generation, interpretation, reporting, delivery, and storage were each harmonized. A compliant and secure network enabled ongoing review and reconciliation of clinical interpretations, while maintaining communication and data sharing between clinicians and investigators. A total of 202 individuals had positive diagnostic findings relevant to the indication for testing and 1,294 had additional/secondary findings of medical significance deemed to be returnable, establishing data return rates for other testing endeavors. This study accomplished integration of structured genomic results into multiple electronic health record (EHR) systems, setting the stage for clinical decision support to enable genomic medicine. Further, the established processes enable different sequencing sites to harmonize technical and interpretive aspects of sequencing tests, a critical achievement toward global standardization of genomic testing. The eMERGE protocols and tools are available for widespread dissemination. [ABSTRACT FROM AUTHOR]

Wireless sensor network is an emerging technology capable of having low-cost and low-power and battery-powered sensor node. At this point the protocol concentric clustered power-efficient gathering in sensor information systems and clustered general self organized tree based energy-balance routing protocol energy efficient protocol are used to increase the energy and to extend network lifetime. For these achievement of clustering techniques, optimization technique particle swarm optimization is used for data transmission through base station. If the base station is inaccessible region from the cluster-head, energy consumption will be augmented and it can shrink the lifetime of wireless sensor network. To conquer these, multi-hop gateway node is implemented with both protocol to achieve maximum lifetime and energy efficiency of wireless sensor network. To improve the quality-of-service (QoS) placing more number of gateways is required. So we propose a new algorithm nearer optimal algorithm which recursively computes least possible adequate dominating sets, at the time constantly preserving QoS requirements across iterations. In this paper comparison is done in terms of throughput, packets delivery ratio and number of nodes alive. [ABSTRACT FROM AUTHOR]

To optimize energy consumption in wireless sensor networks (WSNs) and prolong life cycle of networks, aiming at the problems in LEACH algorithm, such as random selection of cluster-heads, indeterminate cluster-heads number, accelerated death of cluster-head nodes and so on, an efficient clustering routing algorithm for WSNs (EECR) was proposed. This algorithm is based on LEACH algorithm. In the cluster building stage, four sub-thresholds were designed, i.e. residual energy of node, based on base-station distance, number of cluster-head in networks and round number that nodes are selected as cluster-heads. In stable data transmission stage, the effective path of node was utilized and free spatial model and multi-path attenuation model were integrated to realize effective data transmission. In simulation experiment, the network life, residual energy and information amount received by base station were compared. The results indicate that, compared to LEACH, LEACH-C, HEED and EEUC, the EECR algorithm can effectively reduce energy consumption and prolong network lifetime, and its overall performance is superior to LEACH, LEACH-C, HEED and EEUC algorithms. [ABSTRACT FROM AUTHOR]

Compared with traditional radio frequency identification (RFID), computational RFID (CRFID) tag has more powerful computing capability, but it shows poor performance when it follows EPC Class-1 Generation-2 protocol especially transmitting large amounts of data. In fact, the operation of the CRFID tag entirely depends on the state of energy. For this point, this study proposes an optimised protocol called LILAC. LILAC allows tags to select the communication time slot according to their current voltage value measured by using an analogue-to-digital converter rather than randomly selecting, the authors proposed a more reasonable time slot mapping algorithm for LILAC that increases the success rate of tag responding. In addition, they design a data transmission format that can be retransmitted to improve the uplink throughput. Finally, they implemented LILAC on a CRFID platform and practically measured several parameters to compare with the existing well-known protocol. The results of experiments show that LILAC increases the maximum communication distance by more than half in the access phase and doubles the goodput of the backscatter link in both the inventory and access phase. [ABSTRACT FROM AUTHOR]

On the one hand, the correctness of routing protocols in networks is an issue of utmost importance for guaranteeing the delivery of messages from any source to any target. On the other hand, a large collection of routing schemes have been proposed during the last two decades, with the objective of transmitting messages along short routes, while keeping the routing tables small. Regrettably, all these schemes share the property that an adversary may modify the content of the routing tables with the objective of, e.g. blocking the delivery of messages between some pairs of nodes, without being detected by any node. In this paper, we present a simple certification mechanism which enables the nodes to locally detect any alteration of their routing tables.In particular, we show how to locally verify the stretch-3 routing scheme by Thorup and Zwick, presented in SPAA in 2001, by adding certificates of the same order of magnitude as the original routing tables. We also propose a new name-independent routing scheme using routing tables of size O ˜ (n) bits at each node in n -node networks. This new routing scheme can be locally verified using certificates of O ˜ (n) bits. Its stretch is 3 if using handshaking, and 5 otherwise. [ABSTRACT FROM AUTHOR]

The issue of antenna correlation in multi-pair massive antenna relay network is studied. Under the spatial correlation properties of the channel, an analytical approximation for both upper and lower bounds using popular maximum ratio combining/maximum ratio transmission relaying scheme is developed. This gives an insight of the system achievable rate by exploiting channel reciprocity in the time-division duplex protocol. To this aim five special antenna correlation cases are discussed and the corresponding overall spectral efficiency is analyzed. The performance of the scheme is compared against the other precoding and receiver combining schemes, i.e., zero forcing and minimum-mean-squared-error processing under the antenna correlation model. The analytical results backed up by simulations clearly quantify the impacts of antenna correlation under various cases on user spectral efficiency. [ABSTRACT FROM AUTHOR]

In MANETs, the mobile nodes usually relay other nodes' packets for the proper operation of the network. However, selfish nodes usually don't cooperate in relaying other nodes' packets but use the regular nodes to relay their packets. The increase in the number of selfish nodes affects the network performance badly. Existing protocols try to minimize the impact of selfish nodes with high computation overhead and/or communication overhead. In this paper, triple referee incentive mechanism is proposed that employs three referees to monitor the behavior of any intermediate node. In case of any selfish behavior, the packets will be bypassed through the referee nodes so that the data communication is uninterrupted in the network. In addition, the selfish nodes are motivated through incentives with less packet overhead. Hash operations are used in the data packets and acknowledgement packets instead of the public key cryptography operations so that the average packet overhead is less than that of the public key cryptography based incentive protocols. Hash values are used to attain payment non repudiation and restrain free riding attacks. [ABSTRACT FROM AUTHOR]

With the development of vehicle networks, the information transmission between vehicles is becoming increasingly important. Many applications, particularly regarding security, are based on communication between vehicles. These applications have strict requirements for factors such as the quality of communication between vehicles and the time delay. Many theoretical communication protocols ignore the presence of buildings or other obstacles that are present during practical use, especially in urban areas. These obstacles can cause a signal to fade or even block direct communication. Many vehicles are often parked at the roadside. Because of their location, these parked vehicles can be used as relays to effectively reduce the shadowing effect caused by obstacles and even solve communication problems. In this paper, we study the problem of parked-vehicle-assistant relay routing communication in vehicle ad hoc networks. We propose an efficient parked vehicle assistant relay routing algorithm that is composed of four parts: a periodic Hello packet exchange mechanism, candidate relay list update, communication link quality evaluation, and candidate relay list selection. Simulation results reveal obvious advantages for indexes such as the quality of communication, success rate, and time delay. [ABSTRACT FROM AUTHOR]

The recent development of the vehicular ad hoc networks (VANETs) has motivated an increasing interest in vehicular services and applications, such as active safety service and the infotainment service. Effective data Dissemination has become more and more important in vehicular services sharing. In this paper, the connectivity characteristics of VANETs are theoretically analyzed and implemented to show the partial connections in vehicle to vehicle communication. Hence, we propose the connectivity-aware data dissemination (CADD) in partially connected VANETs will improve the data transmission capacity. In the CADD protocol, a new metric of the node forwarding capability estimation is introduced. The metric is designed by the combination the throughput function and the active connection time estimation. And then, the high efficiency data dissemination protocol is designed by the new metric. Simulation results show that the CADD protocol outperforms existing solutions in terms of the packet delivery ratio, the transmission delay, and the protocol overhead under the condition of the intermittent network connectivity. [ABSTRACT FROM AUTHOR]

We propose a vehicle-to-roadside communication protocol based on distributed clustering where a coalitional game approach is used to stimulate the vehicles to join a cluster, and a fuzzy logic algorithm is employed to generate stable clusters by considering multiple metrics of vehicle velocity, moving pattern, and signal qualities between vehicles. A reinforcement learning algorithm with game theory based reward allocation is employed to guide each vehicle to select the route that can maximize the whole network performance. The protocol is integrated with a multi-hop data delivery virtualization scheme that works on the top of the transport layer and provides high performance for multi-hop end-to-end data transmissions. We conduct realistic computer simulations to show the performance advantage of the protocol over other approaches. [ABSTRACT FROM AUTHOR]

In a distributed computing environment, real-time tasks communicate via a network infrastructure whose stability significantly impacts timing predictability. Network stability includes two aspects. First, the network has to guarantee the deadline requirements of real-time message transmissions in the absence of network failures. Second, the network needs to support dynamic recovery when network failures occur. This paper generalizes previous static routing approaches, which address the first aspect of the network stability, by developing a dynamic failure recovery policy and a protocol to address the second aspect of the network stability. We derive new real-time forwarding paths without compromising the capability of network devices to guarantee deadlines of concurrent real-time transmissions. We implement this mechanism on a network simulation platform and evaluate it on real hardware in a local cluster to demonstrate its feasibility and effectiveness. Experiments confirm the ability to bound recovery delays based on the network parameters. [ABSTRACT FROM AUTHOR]

Internet of vehicles (IoV) is a branch of the internet of things (IoT) which is used for communication among vehicles. As vehicular nodes are considered always in motion, hence it causes the frequent changes in the topology. These changes cause major issues in IoV like scalability, dynamic topology changes, and shortest path for routing. Clustering is among one of the solutions for such type of issues. In this paper, the stability of IoV topology in a dynamic environment is focused. The proposed metaheuristic dragonfly-based clustering algorithm CAVDO is used for cluster-based packet route optimization to make stable topology, and mobility aware dynamic transmission range algorithm (MA-DTR) is used with CAVDO for transmission range adaptation on the basis of traffic density. The proposed CAVDO with MA-DTR is compared with the progressive baseline techniques ant colony optimization (ACO) and comprehensive learning particle swarm optimization (CLPSO). Numerous experiments were performed keeping in view the transmission dynamics for stable topology. CAVDO performed better in many cases providing minimum number of clusters according to current channel condition. Considerable important parameters involved in clustering process are: number of un-clustered nodes as a re-clustering criterion, clustering time, re-clustering delay, dynamic transmission range, direction, and speed. According to these parameters, results indicate that CAVDO outperformed ACO-based clustering and CLPSO in various network settings. Additionally, to improve the network availability and to incorporate the functionalities of next-generation network infrastructure, 5G-enabled architecture is also utilized. [ABSTRACT FROM AUTHOR]

In this paper, we consider multichannel ALOHA for a wireless sensor network (WSN), where sensors’ signals are correlated. The impact of the number of channels on the length of information that an access point (AP) can collect is investigated. Under a certain distributed signal source model, in order for the AP to have a sufficiently long length of information, we show that the number of channels is to be larger than the square of the average number of active nodes. Thus, when the number of channels is limited, we need to use re-transmissions. To this end, we propose an adaptive transmission approach that can effectively exploit the correlation between the collected signals at the AP and nodes’ signals using Slepian–Wolf coding to shorten the total transmission time, which results in a more energy efficient WSN. [ABSTRACT FROM AUTHOR]

It is essential to reduce data latency and guarantee quality of service for modern computer networks. The emerging networking protocol, Multipath Transmission Control Protocol, can reduce data latency by transmitting data through multiple minimal paths (MPs) and ensure data integrity by the packets retransmission mechanism. The bandwidth of each edge can be considered as multi-state in computer networks because different situations, such as failures, partial failures and maintenance, exist. We evaluate network reliability for a multi-state retransmission flow network through which the data can be successfully transmitted by means of multiple MPs under the time constraint. By generating all minimal bandwidth patterns, the proposed algorithm can satisfy these requirements to calculate network reliability. An example and a practical case of the Pan-European Research and Education Network are applied to demonstrate the proposed algorithm. [ABSTRACT FROM AUTHOR]

In the medium access control layer (MAC) of WSN, the scheduling mechanism of nodes based on the periodical listen/sleep is an effective way of saving node energy consumption. In the case of data transmission which is not affected reduces the nodes’ proportions, we improve the protocols based on asynchronous MAC. This paper discusses a protocol which is a low duty cycle energy-efficient MAC protocol for WSN and can be adaptively updated based on the prediction nodes’ wake-up time. We call it AP-MAC protocol. In AP-MAC protocol, the nodes will not wake up or send data in the same period, and they will wake up in random time according to the algorithm that has been set. In this case, the network can avoid the problem of collision, cross-talk, etc. caused by all the nodes’ wake-up in the same time, and save more energy. To ensure the reliable transmission of network data, the node which sends data will predict the wake-up time of receiving nodes and ensure the receiving nodes wake up timely and establish a connection with sending note. At the same time, we join several adaptive update mechanisms in the network according to the dynamic changes of it. The experimental results show that the improved protocol not only can save the network energy consumption by effectively reducing the overall duty cycle of the network nodes and improving the reliable transmission of data but also can improve the adaptability of the network. [ABSTRACT FROM AUTHOR]

Effective techniques for extending lifetime in multi-hop wireless sensor networks include duty cycling and, more recently introduced, cooperative transmission (CT) range extension. However, a scalable MAC protocol has not been presented that combines both. An On-demand Scheduling Cooperative MAC protocol (OSC-MAC) is proposed to address the energy hole problem in multi-hop wireless sensor networks (WSNs). By combining an on-demand strategy and sensor cooperation intended to extend range, OSC-MAC tackles the spatio-temporal challenges for performing CT in multi-hop WSNs: cooperating nodes are neither on the same duty cycle nor are they necessarily in the same collision domain. We use orthogonal and pipelined duty-cycle scheduling, in part to reduce traffic contention, and devise a reservation-based wake-up scheme to bring cooperating nodes into temporary synchrony to support CT range extension. The efficacy of OSC-MAC is demonstrated using extensive NS-2 simulations for different network scenarios without and with mobility. Compared with existing MAC protocols, simulation results show that while we explicitly account for the overhead of CT and practical failures of control packets in dense traffic, OSC-MAC still gives 80-200 % lifetime improvement. [ABSTRACT FROM AUTHOR]

An opportunistic network is a wireless ad hoc network that has frequently intermittent connectivity due to nodes’ mobility. These spare, unpredictable networks aim to solve the prolonged delay paths by a store-carry-forward scheme. It is difficult to determine the appropriate nodes to forward the messages since there are few opportunistic contacts. The nodes might decide based on the obtained data of the network as a guide to reach a destination. The aforementioned technique is not helpful in case the rate of change in the network topology is higher than the rate of data gathering due to usage restrictions and uncertain available information/knowledge of the future contacts. In this paper, to cope with the challenges imposed by the un-deterministic environment, a risk assessment strategy is considered to evaluate the short and long-term impact of each decision to find the optimal node/paths. This routing scheme can take advantage of the unanticipated connection to make the routing more flexible in short time and with less buffer usage. Our proposed risk assessment algorithms that are based on MALP are mixed with the knowledge about buffer management and network capacity. The prioritized messages to be disseminated as well as better decision to take a risk are the main contributions of this paper. Moreover, the self-adaptive threshold, distributed PID controller, is considered to tackle different threshold levels for each node individually. Numerical results prove that the proposed method drastically increases the delivery ratio and also minimizes the risk of exceeding resource consumption and packet loss. [ABSTRACT FROM AUTHOR]

A cooperative wireless-powered communication network protocol is proposed, in which user far away from a hybrid access point (H-AP) is capable of harvesting wireless powers by overhearing the uplink signals of users that are relatively nearer to the H-AP, in addition to downlink signal broadcast by the H-AP. In this setting, time allocations for the downlink transmission of the H-AP and the uplink transmission for the users are jointly optimized for two different purposes. First, the weighted sum-rate maximization problem is solved for a given total transmission time. Then, the total transmission time is minimized under a minimum rate constraint, and an efficient algorithm is also presented to solve the optimal solution by a line search strategy. Numerical results demonstrate that the proposed schemes significantly increase the far user's rate, which in turn improves user fairness and transmission delay. [ABSTRACT FROM PUBLISHER]

To support communications of a large number of deployed devices while guaranteeing limited signaling load, low energy consumption and high reliability, future cellular systems require efficient random access protocols. However, how to address the collision resolution at the receiver is still the main bottleneck of these protocols. The network-assisted diversity multiple access (NDMA) protocol solves the issue and attains the highest potential throughput at the cost of keeping devices active to acquire feedback and repeating transmissions until successful decoding. In contrast, another potential approach is the feedback-free NDMA (FF-NDMA) protocol, in which devices do repeat packets in a pre-defined number of consecutive time slots without waiting for feedback associated with repetitions. Here, we investigate the FF-NDMA protocol from a cellular network perspective in order to elucidate under what circumstances this scheme is more energy efficient than NDMA. We characterize analytically the FF-NDMA protocol along with the multipacket reception model and a finite Markov chain. Analytic expressions for throughput, delay, capture probability, energy, and energy efficiency are derived. Then, clues for system design are established according to the different trade-offs studied. Simulation results show that FF-NDMA is more energy efficient than classical NDMA and HARQ-NDMA at low signal-to-noise ratio (SNR) and at medium SNR when the load increases. [ABSTRACT FROM AUTHOR]

Non-ideal channel conditions degrade the performance of wireless networks due to the occurrence of frame errors. Most of the well-known works compute the saturation throughput and packet delay for the IEEE 802.11 Distributed Coordination Function (DCF) protocol with the assumption that transmission is carried out via an ideal channel (i.e., no channel bit errors or hidden stations), and/or the errors exist only in data packets. Besides, there are no considerations for transmission errors in the control frames (i.e., Request to Send (RTS), Clear to Send (CTS), and Acknowledgement (ACK)). Considering the transmission errors in the control frames adds complexity to the existing analysis for the wireless networks. In this paper, an analytical model to evaluate the Medium Access Control (MAC) layer saturation throughput and packet delay of the IEEE 802.11g and IEEE 802.11n protocols in the presence of both collisions and transmission errors in a non-ideal wireless channel is provided. The derived analytical expressions reveal that the saturation throughput and packet delay are affected by the network size (n), packet size, minimum backoff window size (Wmin), maximum backoff stage (m), and bit error rate (BER). These results are important for protocol optimization and network planning in wireless networks. [ABSTRACT FROM AUTHOR]

Road safety applications envisaged for Vehicular Ad Hoc Networks (VANETs) depend largely on the dissemination of warning messages to deliver information to concerned vehicles. The intended applications, as well as some inherent VANET characteristics, make data dissemination an essential service and a challenging task in this kind of networks. This work lays out a decentralized stochastic solution for the data dissemination problem through two game-theoretical mechanisms. Given the non-stationarity induced by a highly dynamic topology, diverse network densities, and intermittent connectivity, a solution for the formulated game requires an adaptive procedure able to exploit the environment changes. Extensive simulations reveal that our proposal excels in terms of number of transmissions, lower end-to-end delay and reduced overhead while maintaining high delivery ratio, compared to other proposals. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are mobile networks, which are automatically outspread on a geographically limited region, without requiring any preexisting infrastructure. Mostly, nodes are both self-governed and self-organized without requiring a central monitoring. Because of their distributed characteristic, MANETs are vulnerable to a particular routing misbehavior, called wormhole attack. In wormhole attack, one attacker node tunnels packet from its position to the other attacker nodes. Such wormhole attack results in a fake route with fewer hop count. If source node selects this fictitious route, attacker nodes have the options of delivering the packets or dropping them. For this reason, this paper proposes an improvement over AODV routing protocol to design a wormhole-immune routing protocol. The proposed protocol called defending against wormhole attack (DAWA) employs fuzzy logic system and artificial immune system to defend against wormhole attacks. DAWA is evaluated through extensive simulations in the NS-2 environment. The results show that DAWA outperforms other existing solutions in terms of false negative ratio, false positive ratio, detection ratio, packet delivery ratio, packets loss ratio and packets drop ratio. [ABSTRACT FROM AUTHOR]

Three factors have been often shown to significantly affect the reliability of real-time transmission in wireless local area networks-transmission rate, power, and packet size. We analyze these factors and determine the optimal combination of factors subject to time constraints that yields the most reliable transmission of real-time data. We propose a cross-layer framework to jointly design the routing and MAC protocol combined with our optimization approach. The approach under a non-real-time routing protocol that produces a path metric is compared with a real-time routing protocol. Additionally, the real-time routing protocol enhances a guaranteed rate with our approach. Our experiments reveal that real-time performance in terms of miss ratio and throughput is significantly increased in lossy link and heavy traffic environments. Miss ratio and average throughput are improved by up to 30% over a state-of-the art routing protocol and 35% over a MAC protocol, respectively. [ABSTRACT FROM AUTHOR]

To improve the efficiency of carrier sense multiple access (CSMA)-based medium access control (MAC) protocol, CSMA with collision resolution (CSMA/CR) has been proposed. In the CSMA/CR protocol, a transmitting station can detect a collision by employing additional carrier sensing after the start of data transmission and resolve the next collision that might occur by broadcasting a jam signal during a collision detection (CD) period. By extending this original CSMA/CR protocol that uses a single CD phase, in this paper we propose a multi-phased CSMA/CR (MP-CSMA/CR) protocol that employs multiple CD phases. In the proposed MP-CSMA/CR protocol, colliding stations are filtered in each CD phase, and only surviving stations compete again in the next CD phase. Therefore, the collision resolution probability becomes higher as the CD phases proceed. Utilizing the multiple CD phases, we analyze the throughput numerically and find optimal operating parameters-such as the number of CD phases and the number of CD slots per phase-that maximize the throughput. Based on this result, we also propose a dynamic MP-CSMA/CR protocol in which the number of CD phases is dynamically changed to suit network conditions. Analysis and simulation results show that the proposed MP-CSMA/CR protocol significantly outperforms CSMA/CR with a single CD phase. The dynamic MP-CSMA/CR protocol achieves a slightly better throughput than MP-CSMA/CR, which uses a fixed optimal number of CD phases. [ABSTRACT FROM AUTHOR]

Opportunistic Mobile Social Networks (OMSNs), formed by mobile users with social relationships and characteristics, enhance spontaneous communication among users that opportunistically encounter each other. Such networks can be exploited to improve the performance of data forwarding. Discovering optimal relay nodes is one of the important issues for efficient data propagation in OMSNs. Although traditional centrality definitions to identify the nodes features in network, they cannot identify effectively the influential nodes for data dissemination in OMSNs. Existing protocols take advantage of spatial contact frequency and social characteristics to enhance transmission performance. However, existing protocols have not fully exploited the benefits of the relations and the effects between geographical information, social features and user interests. In this paper, we first evaluate these three characteristics of users and design a routing protocol called Geo-Social-Interest (GSI) protocol to select optimal relay nodes. We compare the performance of GSI using real INFOCOM06 data sets. The experiment results demonstrate that GSI overperforms the other protocols with highest data delivery ratio and low communication overhead. [ABSTRACT FROM AUTHOR]

The growing popularity of multimedia applications and services needs to support several quality of service metrics such as high throughput, low energy, and jitter, which is a challenging task in mobile ad hoc networks. Because of limited bandwidth, energy constraints, dynamic topology, transmission errors, and fluctuating link stability, the links between adjacent nodes are often not reliable and may break because of node mobility. Link breakage initiates the process of rerouting either at the sender node (the node at which the link breaks) or at the source node. In either case, it leads to packet loss, delivery delays, and increased control overheads. Hence, to attain a minimum quality of service, routing protocols must address the dynamic network topology. Uncertain and varying movement of nodes necessitates stability of the links between such nodes. The objective of this paper is to propose 2 protocols, the first based on link stability and the other based on route stability. Link stability identifies a stable link from the available links to the next hop and determines a stable end-to-end route. The probability of successful transmission of periodic packets is used as a link stability metric to assess the stable path. Acknowledgment -free packets are used to check connectivity in the network. Increased probability of successful transmission implies that the selected link is sustained for longer duration and can deliver packets more reliably or, as a consequence, results in a stable link to deliver a better data rate. With a stable link, there is a reduced possibility of retransmissions, reduced end-to-end delay, reduced control overheads, and enhanced data delivery ratio. Selection of the most stable route for data transmission improves the performance. Experimental results from simulations performed on EXata/Cyber v2.0 simulator reveal that our proposed protocols are an improvement over the existing protocols in terms of packet delivery ratio, average end-to-end delay, and average route lifetime, even without route optimization with the minor increase in control packets. A case study of the application of proposed protocols is also presented. [ABSTRACT FROM AUTHOR]

With the rapid increase of space applications, the amount of information to be transmitted between spacecrafts and ground stations increases exponentially and space–sky–ground Transport Control Protocol (TCP) network is highly demanded. However, the traditional TCP cannot be directly applied to space data communication. This article deeply studies the TCP/Network Coding (NC), which can effectively improve terrestrial wireless communication system throughput. Combined with characteristics of Space Communication Protocol Specification-Transport Protocol (SCPS-TP) and advantages of terrestrial TCP/NC, an improved protocol referred to as SCPS-TP/NC, is proposed for space data communication. This article provides detailed process of protocol design, mathematical modelling and throughput analysis of the proposed SCPS-TP/NC. Finally, we implement the SCPS-TP/NC protocol and evaluate its performance by Network Simulator (Version 2). Simulation results show that SCPS-TP/NC can effectively increase the end-to-end system throughput, reduce the packet loss rate, shorten the transmission delay and improve the Quality of Service (QoS) of space data communication to a certain degree. [ABSTRACT FROM AUTHOR]