Cooperative Forwarding Research Articles

An Opportunistic Routing Based on Directional Transmission in the Internet of Underwater Things

The Internet of Underwater Things (IoUT) has attracted a lot of attention because of its promising applications in underwater environmental monitoring; however, the characteristics of acoustic communication, e.g., long propagation delay and high attenuation, pose great challenges for efficient and reliable underwater data transmission. Currently, opportunistic routing is regarded as a key technology to improve the packet delivery ratio, because it can dynamically choose several forwarding nodes and leverage their cooperative forwarding to increase network throughput. However, choosing an excessive number of forwarding nodes may result in energy waste and lengthy communication delays. Therefore, an Opportunistic Routing based on Directional Transmission (ORDT) is studied to improve packet delivery timeliness and reliability and lower energy consumption. ORDT mainly contains three phases: forwarding area division, candidate forwarder selection, and candidate forwarder coordination. The forwarding region is first established based on directional transmission. Only neighbors located in the forwarding region can forward packets. Following that, candidate forwarders in the forwarding region are chosen depending on their forwarding capability. Additionally, the chosen candidate’s time of holding packets is specified so that they might collaborate to reduce redundant data transmission and transmit packets to gateway nodes. Then, an Autonomous Underwater Vehicle (AUV) is employed to gather packets from gateway nodes. Simulation findings demonstrate that ORDT performs better than existing opportunistic routing in terms of packet delivery success rate, transmission latency, and energy usage.

Ultraviolet random access collaborative networking protocol based on time division multiple access

The ultraviolet network, with its advantages of high security, non-line-of-sight communication, and all-weather operation, has broad military application potential. This study proposes an ultraviolet random access collaborative networking protocol based on time division multiple access that combines the benefits of synchronous and asynchronous media access control protocols. Considering the physical layer characteristics, the frame structure of the protocol is constructed based on a cross-layer design. Compared with the time division multiple access protocol, the proposed protocol can achieve higher throughput with a lower delay and packet loss rate by the dynamic timeslot allocation mechanism. Then, the effects of maximum cache capacity and burst traffic on network performance are investigated. Finally, the conducted network experiments prove the cooperative forwarding and random access capabilities of the ultraviolet random access collaborative networking protocol. The proposed protocol provides a reliable and effective method for independent and flexible ultraviolet networks.

Performance Optimization for Decode and Forward Cooperative Cognitive Radio Networks

This paper considers the problem of optimizing the data rate of the cooperative cognitive system subject to the dual constraints of the interference threshold of primary users and power budget of secondary users. In particular, under a single constraint, the rate can reach its peak easily. But under the double restrictions, the peak rate problem becomes complicated and changeable. According to different interference conditions and power supplies, four scenarios are formulated: total interference threshold and total power budget, total interference threshold and separate power budget, separate interference threshold and total power budget, and separate interference threshold and separate power budget. Each scenario needs to be further divided into many situations for discussion due to the sheer particularity. Through careful comparison and classification, we summarize and formulate each situation one by one to achieve the optimal value of the rate. Extensive simulation results demonstrate that the proposed resource allocation policy represents the best compromise between enhancing the rate of the secondary users and satisfying the interference threshold requirements of the primary users.

A Contention-Free Cooperative MAC Protocol for Eliminating Heterogenous Collisions in Vehicular Ad Hoc Networks

In vehicular ad hoc networks (VANETs), efficient data dissemination to a specified number of vehicles with minimum collisions and limited access delay is critical for accident prevention in road safety. However, packet collisions have a significant impact on access delay, and they may lead to unanticipated link failure when a range of diversified collisions are combined due to complex traffic conditions and rapid changes in network topology. In this paper, we propose a distributed contention-free cooperative medium access control (CFC-MAC) protocol to reduce heterogenous collisions and unintended access delay in stochastic traffic scenarios. Firstly, we develop a cooperative communication system model and cooperative forwarding mechanism to explore the optimum road path between the source and destination by identifying the potential cooperative vehicles. Secondly, we propose a vectorized trajectory estimation mechanism to suppress merging collisions by identifying the relative velocity of vehicles with different speeds in a specific time interval. Based on the case study, typical heterogeneous collisions and aggregated heterogeneous collisions at dissociated positions and associated positions are investigated. In both cases, we propose the corresponding collision-resolving mechanisms by methodically recapturing the colliding time slot or acquiring the available free time slots after identifying the access vehicles and comparing the received signal strengths. Performance analysis for collision probability and access delay is conducted. Finally, the simulation results show that the proposed protocol can achieve deterministic access delay and a minimal collision rate, substantially outperforming the existing solutions.

Adaptively prioritizing candidate forwarding set in opportunistic routing in VANETs

Opportunistic routing (OR) paradigms in vehicular networks via opportunistic candidate set selection have a better performance over the pre-defined next-hop node in terms of packet delivery rate. Nevertheless, uneven vehicle distribution, highly dynamic topology, varying link interference, and bandwidth restrictions impose drastic challenges for satisfying applications requirements in static prioritizing candidate set selection policies. Besides, fulfilling quality of service (QoS) requirements of heterogeneous applications, due to the limited local topology perspective and many involving conflicting routing criteria, will be further compromised. Considering the candidate set selection policy as a Multi-Criteria Decision Making (MCDM) task, an adaptive two-hop cooperative forwarding set selection strategy called APFS is proposed in this paper. By developing a local topology perspective to the two-hop neighbor information, the APFS scheme jointly considers indicators of link stability, delay assessment, and link good-put as routing criteria. Analytical Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods are employed in two different scenarios in prioritizing candidate forwarding sets. First, classical AHP-TOPSIS technique with a mutable pair-wise comparison matrix is applied, and then Neutrosophic Set (NS) is combined with the classical AHP-TOPSIS method to handle ambiguous vehicular environments. The simulation results show that the APFS strategy using both prioritization policies have significantly improved the performance of packet delivery ratio, average end-to-end delay, throughput, and hop counts as compared to other schemes.

Dual-Mode Data Forwarding Scheme Based on Interest Tags for Fog Computing-Based SIoVs

Social Internet of vehicles (SIoVs) is a combination of vehicular ad-hoc networks (VANETs) and mobile social networks (MSNs). Although social relationships between vehicle nodes are more stable than location changes of vehicle nodes in SIoVs, there always are the problems of data forwarding optimization and adaptability for dynamic networks. In this paper, we propose a dual-mode data forwarding scheme based on interest tags for fog computing-based SIoVs. In the first data forwarding mode, the vehicle nodes calculate and use the cooperation degrees to select the next cooperative forwarding nodes until the data is forwarded to the destination node. In the second data forwarding mode, the RSUs assist the data forwarding of vehicle nodes based on the RSU ranking mechanism of interests, where the fog servers calculate the RSU ranking table of all the interests and the related RSU selects the top- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> RSUs to forward the data according to the RSU ranking table. The experimental results show that our proposed scheme is more efficient and stable than other related schemes by the comparisons of delivery ratio, overhead ratio and average hop count.

Performance evaluation and energy optimization of CM3A cooperative WBAN

This work presents performance evaluation and energy optimization of a cooperative Wireless body area network (WBAN). Link metrics like Bit Error Rate (BER), Signal-to-Noise ratio (SNR), spectral efficiency (SE), and outage probability have been investigated to evaluate the performance of non-cooperative and cooperative WBAN at different frequency bands supporting body-centric communication (Ultra-wideband (UWB), Worldwide Industrial, Scientific and Medical (W-ISM) band, US-ISM (U-ISM) band and Wireless Mobile Telemetry Services (WMTS)). Evaluation reveals that cooperative communication shows better performance by exhibiting improved SNR and SE and lower BER and outage probability compared to non-cooperative communication. A critical comparison of Amplify and forward (A&F) cooperation has been performed with decode and forward (D&F) cooperation. Results reveal that the D&F scheme performs better with increased SNR and SE and lower levels of BER and outage probability in comparison to the A&F scheme by 43.74%, 1.64%, 0.15%, and 99%, respectively. W-MTS with the highest SNR and SE and lowest BER and outage probability outperforms the other frequency bands under both non-cooperative and cooperative scenarios. Further, the threshold distance has been evaluated using the Eigenvalues to optimize the transmission energy for the D&F scenario to enhance the performance of on-body WBAN resulting in an average decrease of 3.8% in the transmitted energy, with UWB showing a maximum reduction of 5.25% thus making the network more energy efficient.

Security in IoT Mesh Networks Based on Trust Similarity

Internet of Things (IoT) Mesh networks are becoming very popular to enable IoT devices to communicate without relying on dedicated PC services. Internet of Things (IoT) implicitly uses mesh networks. IoT connectivity to cloud and edge computing is in vogue. A Wireless Mesh Network (WMN) is a multi-hop and distributed wireless network with mesh routers and mesh clients. Data originating from mesh clients are forwarded to destinations through mesh routers. In IoT Mesh networks, mesh clients are IoT devices. The crucial security issue with these networks is the lack of a trusted third party for validation. However, trust between nodes is required for the proper functioning of the network. WMNs are particularly vulnerable as they rely upon cooperative forwarding. In this research work, a secure and sustainable novel trust mechanism framework is proposed. This framework identifies the malicious nodes in WMNs and improves the nodes’ cooperation. The proposed framework or model differentiates between legitimate and malicious nodes using direct trust and indirect trust. Direct trust is computed based on the packet-forwarding behavior of a node. Mesh routers have multi radios, so the promiscuous mode may not work. A new two-hop mechanism is proposed to observe the neighbors’ packet forwarding behavior. Indirect trust is computed by aggregating the recommendations using the weighted D-S theory, where weight is computed using a novel similarity mechanism that correlates the recommendations received from different neighbors. Dynamic weight computation calculates the overall trust by using several interactions. We present the evaluations to show the effectiveness of the proposed approach in the presence of packet drop/modification attacks, bad-mouthing attacks, on-off attacks, and collusion attacks by using the ns-2 simulator.

Physical Layer Secrecy by Power Splitting and Jamming in Cooperative Multiple Relay Based on Energy Harvesting in Full-Duplex Network

In this article, we investigated the secrecy performance of a three-hop relay network system with Power Splitting (PS) and Energy Harvesting (EH). In the presence of one eavesdropper, a signal is transferred from source to destination with the help of a relay. The source signal transmits in full-duplex (FD) mood, jamming the relay transfer signals to the destination. The relay and source employ Time Switching (TS) and Energy Harvesting (EH) techniques to obtain the power from the power beacon. In this study, we compared the Secrecy Rate of two Cooperative Schemes, Amplify and Forward (AF) and Decode and Forward (DF), for both designed systems with the established EH and PS system. The Secrecy Rate was improved by 50.5% in the AF scheme and by 44.2% in the DF scheme between the relay and eavesdropper at 40 m apart for the proposed system in EH and PS. This simulation was performed using the Monto Carlo method in MATLAB.

Practical Partner Selection of Chip-Interleaved Decode and Forward Cooperation in WSNs Subject to Frequency-Selective Fading

Practical Partner Selection of Chip-Interleaved Decode and Forward Cooperation in WSNs Subject to Frequency-Selective Fading

Selection Combiner in Time-Varying Amplify Forward Cooperative Communication

This research presents the diversity combining schemes for Multiple Symbol Double Differential Sphere Detection (MSDDSD) in a time-varying amplify-and-forward wireless cooperative communication network. Four diversity combiners, including direct combiner, Maximal Ratio Combiner (MRC), semi MRC and Selection Combiner (SC) are demonstrated and explained in details. A comprehensive error probability and outage probability performance analysis are carried through the flat fading Rayleigh environment for semi MRC and SC. Specifically, error performance analysis is obtained using the PDF for SC detectors. Finally, power allocation expression based on error performance minimization approach is presented for the proposed SC performance optimization. It is observed that the performance analysis matches well with the simulation results. Furthermore, the proposed SC scheme offers better performance among the conventional MRC and direct combiner schemes in the presence of frequency offsets.

Outage and Rate Evaluation of Drone based Decode and Forward Cooperation for Hybrid Fading Channels

In this paper, we consider a drone as a relay in Cooperative Communication (CC) to improve the network performance in an upcoming wireless network. Drone Assisted CC (DACC) is more useful when the central coordinator (base station) gets disrupted. In such a scenario, the drone works as an aerial relay and provides CC diversity to the end-users. In this article, a Decode-and-Forward (DF) protocol is used as a relaying scheme at the drone, and the Maximal Ratio Combining (MRC) scheme is used at the end-users for combining the direct and relayed signal. Here, we assume Nakagami faded channel among Airto- Ground (A2G) links and Rayleigh faded distribution between Ground-to-Ground (G2G) links. The performance of DA-CC is evaluated in a hybrid channel environment and compared based on drone height, rate, horizontal distance, and transmitted power with the existing Rayleigh and Nakagami faded distributions. The analytical expression of outage probability and the rate have been derived for analysis purposes, and Monte-Carlo simulations are used to verify the analytical results. This work can have security and surveillance applications to improve the network performance in the absence of a central base station.

Performance Analysis of Multi-Hop Decode and Forward Cooperative Communications Under Rayleigh Fading Channel

Performance Analysis of Multi-Hop Decode and Forward Cooperative Communications Under Rayleigh Fading Channel

Research on routing method of Multipath D2D Communication based on forward cellular network

Traditional communication route selection methods find the shortest communication path based on graph theory, ignoring the influence of communication parameter changes on routing selection, resulting in excessive consumption of communication resources. In order to solve the above problems, a multi-channel D2D communication routing method based on Forwarding cellular network is proposed. Based on the establishment of D2D cooperative forwarding mechanism in cellular network, the mathematical model of multi-channel D2D routing is constructed by adding QoS index. In D2D, the multi-channel routing of D2D is calculated by mathematical model. The results show that the proposed routing method not only has low transmission delay, but also can control the resource loss within 15% with good reliability.

How can the European Commission help Europe’s defence industry? By making the most out of what it is already doing

ABSTRACT The European Commission's proposal for the €13 bn European Defence Fund (EDF) to incentivise collaborative defence research and capability development projects with EU funding was an ambitious statement of policy intent to drive forward European defence cooperation. However, the summer 2020 EU budget negotiations left it with only about 60% of that amount over the 2021-2027 period. This debate contribution argues that despite this curtailment in resource and ambition, the European Commission can still maximise the EDF's impact to benefit European defence industry by ensuring that the various defence industrial policy activities it is already leading are achieving their full potential, incentivising EU governments to acquire and use the capabilities developed through the Fund, and maintaining coherence amongst existing research projects, capability development projects, and joint capability requirements.

Bit error probability analysis of IR-UWB ED-OOK system using cooperative dual-hop DTF strategy

The Bit Error Rate (BER) of a single user cooperative Impulse Radio (IR)-Ultrawideband (UWB) communication system employing Energy Detector (ED) receiver with On-Off Keying (OOK) in IEEE 802.15.4a UWB multipath environment is investigated in this paper. Analytical evaluation based on Energy detection principle is performed to derive approximate BER Expressions for various diversity combining cases, namely optimum combining, linear combining and selective combining using cooperative dual-hop Detect and Forward (DTF) relay protocol in presence and absence of Inter-symbol interference (ISI). Numerical results reveal that there is a significant improvement in BER, with increase in number of relay diversity paths and decrease in number of frames Nf. The accuracy and perfection in approximation used in investigation of BER is confirmed with the validation of the analytical BER expressions with that of the simulation results. The analytical and simulation results confirm that among the diversity combining schemes, the performance of optimum combining is better compared with linear combining, which in turn performs better than selective combining.

Link Stability Inspired Hopping Technique for Detection and Alleviation of Malicious Adversaries

In multi-hop ad hoc network, the network organization exhaustively relies on the trust relationship that exists between the participating mobile nodes of the network. Secure and trustworthy mechanisms are necessary for enforcing collaboration between the mobile nodes. Further, the malicious adversaries that intentionally injure or compromise network functionality during the process of multi-hop communication need to be detected and isolated from the network. Specifically, malicious adversaries like selfish nodes and root node attacks that exploits the network resources without rendering cooperation in routing or packet forwarding is a major challenge that need to be handled. The core aim of this proposed Link Stability Inspired Hopping Technique concentrates on the classification of mobile nodes into malicious and benevolent nodes based on the computation of link stability factor. This discrimination between the mobile nodes is achieved by the computation of Contention count, Signal strength, Hop determination, Link energy availability and normalized multi-objective optimization function for facilitating the elimination of malicious adversaries so as to improve the rate of data dissemination in the network. The interactions between the mobile nodes are periodically monitored for testing its link stability based on which the mobile nodes may be identified as co-operative and malicious.

A Partial Amplify and Forward Cooperative Communication Strategy Based on Blind Signal Detection

Due to the great potential in extending propagation distance and enhancing the link reliability, amplify and forward (AF) cooperative communications have attracted much attention recently. However, the existing studies mainly focus on the energy consumption analysis and optimization, and also the channels used in communications are based on Rayleigh/Rician fading model, and/or it was usually supposed that the channel state information (CSI) is known or can be acquired by a training sequence. In this paper, blind signal detection for AF cooperative communication systems based on time division multiple access (TDMA) is studied, in which the channels are modeled as frequency selective fading and the CSI are unknown. A blind signal detection algorithm of partial amplify and forward (PAF) cooperative communication is proposed based on semidefinite relaxation (SDR). This method can recover the data without the training sequence and need not to implement blind equalization for the unknown channels. With the correlation between data of different links, the proposed method can obtain the optimal solution efficiently and achieve better performance of signal detection than the traditional algorithm. By simulations, the energy consumption efficiency as well as the overall system performance of the proposed strategy are verified.

Performance Evaluation of Best Path Selection using Multi Hop Decode and Forward Cooperative system

In this method , examined that Multibounce correspondence is the most ideal route for improving the inclusion region with decreased transmitted power. From this, we can without much of a stretch finding a way determination dependent on multi-jump translate and forward (DF) agreeable framework. At that point, it is said to be a basic parallel multibounce ways based agreeable correspondence framework. Assumed all jumps on the whole agreeable ways are presenting to allowed Rayleigh blurring. Picking the better way in the greatest multi-jump interface between the source and goal is determined by choosing the max-min determination criterion. The transfers which are found in the chose helpful way to utilize the image astute DF convention in the demodulate to get the information from the previous hub with the assistance of image astute way and it is sent to the succeeding hub. A systematic structure is progressed to locate an exact blunder execution of the given framework. In ongoing we determine a right articulation for the normal piece blunder rate of the maximum min foundation based upon the best way choice plan, all together with the united power arrangement. The coding gain and the assorted variety request of the plan are moreover determined with the assistance of the explanatory strategy.

OCA-MAC: A Cooperative TDMA-Based MAC Protocol for Vehicular Ad Hoc Networks.

Cooperative communication is an effective method of improving the transmission performance for vehicular ad hoc networks. However, the rapid movement of vehicles leads to frequent changes in network topology and reduces the probability of successful data transmission on the medium access control (MAC) layer. In this paper, we propose an Optimal Cooperative Ad hoc MAC protocol (OCA-MAC) based on time division multiple access (TDMA). OCA-MAC utilizes multiple cooperative nodes to forward data, so as to improve the probability of successful data transmission. It chooses cooperative nodes according to direct successful transmission probability, communication range between potential helper node and destination node, and available time slot. Meanwhile, in order to avoid excessive transmission redundancy caused by multiple cooperative forwarding, the optimal number of cooperative forwarding nodes is obtained through analysis of a probabilistic model. Simulation results show that OCA-MAC improves the successful data transmission rate and reduces the number of transmission times and transmission delay compared to the multichannel TDMA MAC protocol (VeMAC) and the cooperative ad hoc MAC protocol (CAH-MAC).