Cooperative Wireless Networks Research Articles

Performance analysis of successive di-state full-duplex cooperative wireless cellular networks

This paper examined uplink and downlink di-state (primary and secondary) situations to build the theoretical and practical realization of a bidirectional cooperative wireless cellular network. In the primary scenario, full-duplex (FD) base stations support two sets of half-duplex (HD) users, where the transmitter (uplink) and receiver (downlink) respectively. Each uplink transmitted signal is rotated in a variant phase through a set of scalars known to the base stations before transmission. The signal from the transmitter ensures the reconfigurable receiver antennas at the base stations can configure the received signal as decoded signals. The proposed work exposed strong self and inter-user interference from the transmitter during demonstrating FD wireless communication mode that destroyed network functionality at the base stations. The occurred self-interference signals from the transmitter are neutralized using precoding and beam-forming technique. During the secondary scenario, decoded base station signals are independently encoded and transmitted to the downlink users. Base stations aid the inter-user interference management by precoding the uplink transmission data and forwarding it to the downlink users. Consequently, the inter-user interference signals are aligned using the span interference alignment technique. A proposed cooperative additional receiver (listener U1) can decode the desired signals and helps in recovering and reconstructing the interference signals. This proposed work completely characterized and evaluated the degree of freedom (DoF) for unknown channel state information at the transmitter (CSIT); whereas achievable lower and upper bound DoF are demonstrated for the partial CSIT. At last, the analytical and simulation results reveal the sum of DoF improvement for unknown and partial CSIT.

Joint metaheuristics-based optimisation in wireless cooperative network

Joint metaheuristics-based optimisation in wireless cooperative network

Scheduling in Wireless Cooperative Localization Networks with Intelligent Eavesdroppers

Location-based service based on wireless cooperative localization networks is becoming ubiquitous nowadays. However, since the fact that most location network nodes are resource-limited, recent investigations focus on the proper network scheduling strategies that can significantly enhance the system performance, including but not limited to localization accuracy and energy efficiency. In addition to the current efficient nondata-aided strategies, we find that some silent nodes, called “eavesdroppers,” can be helpful to the localization task without transmitting any signals. In this paper, we first formulate the eavesdropping scheduling policy in practical asynchronous cooperative wireless localization networks. Then, we perform resource optimization in different eavesdropping-based strategies. Both two-slot and multislot strategies are considered, and three types of listening modes are designed from a practical point of view. Numeric results show that, for the scenario with a blocked propagation path, the localization error of networks with dedicated eavesdroppers is only 21% of the conventional networks. Besides, the system with eavesdropping anchors could improve the localization performance by 70%. The result could provide meaningful insights into the practical low-complexity location network deployment and development.

Distributed Space Shift Keying in Cooperative Wireless Networks: Capacity Analysis and Error Performance

In this study, a distributed fashion of space shift keying as an efficient cooperative framework is proposed and studied to address the main challenges in future cellular networks by providing high energy efficiency and meeting the demand growth with the lowest complexity and the highest performance. A comprehensive mathematical analysis has been performed to find a closed form for the channel capacity of distributed space shift keying and to depict the influence of the number of distributed antennas on the achievable channel capacity. In addition, a simulation study of the error performance is presented using two detection methods: maximum-likelihood detection based on channel state information and blind detection. It was shown that as the number of cooperating relays increases, the error performance of the detectors converges, although they incur different costs and computational complexities. A comparison study in terms of error performance and capacity is applied with other cooperative spatial modulation to portray the outperformance of the system presented in this work.

Dynamic rate and channel use allocation for cooperative wireless networks

In this paper, we investigate the performance of link adaptation (LA) algorithms for cooperative multiple access multiple relay networks. In the first transmission phase, the sources transmit in turn in consecutive time slots. In the second cooperative retransmission phase, the destination schedules one relaying node to send redundancies. LA is a fundamental mechanism allowing the source nodes to adapt to the radio channel conditions. In this paper, we investigate the problem of rate allocation using a centralized method, where the destination is the central node that determines the source rates. Furthermore, and in sharp contrast with existing cooperative transmission schemes, we consider the packet size to be time-varying. In other words, we propose adapting the slot duration of each of the sources during the transmission phase as a new degree of freedom. Accordingly, the LA process determines the rate and the time slot duration of each source. We consider a practical performance metric namely, the network spectral efficiency. This metric being difficult to be optimized (given the complex multi-variable optimization problem), we propose best-response dynamic (BRD) algorithms to solve the rate and time duration allocation. Then, we conduct a thorough performance analysis using Monte-Carlo simulations. Our numerical results validate the effectiveness of the proposed BRD algorithms as they yield performance close to the corresponding exhaustive search approach. Furthermore, the results ensure the gain of exploiting the new degree of freedom of the variable slot duration.

Optimal Secure Channel Access in Distributed Cooperative Networks With Untrusted Relay

This paper investigates optimal channel access strategies to improve secure communications over a distributed cooperative wireless network with multiple user pairs and an untrusted amplify-and-forward (AF) relay. The user pairs communicate directly or via the relay. To enable secure communication, we formulate a channel access problem to maximize the average secrecy system throughput with destination-based jamming. Using optimal sequential planned decision theory, we propose an optimal channel access strategy where the winning user pair uses direct transmission, cooperative AF relaying, or cooperative jamming in an adaptive manner. We rigorously prove the optimality of the solution and provide a distributed channel access algorithm based on the pure threshold structure, which is easy to implement. Numerical results demonstrate effectiveness and efficiency of the proposed strategy compared to alternatives.

Double threshold based optimal device selection scheme for D2D or Sidelink network

Device-to-device (D2D) or Sidelink aided communication is regarded as one of the most promising technologies to improve the spectral efficiency of the 5G and beyond communication system. However, two main challenges exist: 1) the selection of the optimal number of devices for improving the spectral efficiency, and 2) improving the physical layer security of such a communication system. The optimal device improves the secrecy capacity, and the selection of optimal devices enhances the physical layer security. Therefore, in this paper, we propose a double threshold-based optimal device selection (ODS) scheme for a cooperative wireless network with amplify and forward (AF) protocol in the presence and absence of an eavesdropper to enhance the physical layer security for the D2D network. The proposed scheme is analyzed with different distance cases, device scenarios, and modulation schemes. The bit error rate (BER) performance analysis concludes that a performance gain of more than 4 dB is achieved at the BER of 0.004 for the proposed double threshold-based ODS scheme compared to the existing ODS scheme at a high signal to noise ratio (SNR). Furthermore, the proposed scheme enhances the physical layer security.

Deep neural network based UAV deployment and dynamic power control for 6G-Envisioned intelligent warehouse logistics system

The intelligent warehouse logistics system (IWLS) is an essential component in the emerging industry 5.0. To well assist the IWLS, advanced network architecture and control policies with the adaptive capability to the variation of traffic should be specially designed. In this paper, we consider an air-and-ground cooperative wireless network that enables dynamic coverage to support the flexible scheduling of the automatic guided vehicles (AGVs) in the IWLS. Jointly considering the dynamic deployment of unmanned aerial vehicles (UAVs) as well as the adaptive power control of AGVs, we formulate a two time-scale network control problem to minimize the transmission power consumption of all AGVs under their individual rate requirement. On large time scales, we first propose a particle swarm optimization based algorithm (PSOA) to obtain the deployment position of the ABS. Then, using the results of the PSOA as training data, we design a deep neural network (DNN) framework aimed at reducing the computational time of the PSOA. On small time scales, we devise an online power control algorithm (OPCA) by using some of stochastic network optimization methods. With current channel conditions, the OPCA can generate the real-time power control policy and ensure the long-term rate requirement. Numerical simulations indicate that the DNN framework enhances the coverage performance of the network only consuming a few milliseconds of computation time. Incorporated with the OPCA, the total transmission power of the AGVs is significantly reduced.

Security-Reliability Tradeoff Analysis of Untrusted Full-Duplex Relay Networks

In this work, we investigate the physical layer security problem of wireless cooperative network, where the communication from a source to a destination is assisted by an untrusted full-duplex amplify-and-forward (AF) relay. In order to realize a positive secrecy rate, cooperative jamming is exploited at the destination. The secrecy outage probability (SOP), connection outage probability (COP), and effective secrecy throughput (EST) are, respectively, derived in closed-form expressions for the fixed gain relaying (FGR) scheme and the variable gain relaying (VGR) scheme. Subsequently, we conduct an asymptotic analysis for both the relaying schemes in the high signal-to-noise ratio (SNR) region to offer valuable insights into practical design. Theory and simulation results demonstrate that the self-interference caused by full-duplex transmission is harmful for the reliability performance, while it is beneficial to the security performance. Moreover, the EST of the considered system increases as the self-interference level decreases, which implies that the self-interference deteriorates an overall performance in terms of the security-reliability tradeoff.

Performance Evaluation of a Wireless Cooperative Network with Maximal Ratio Combining Technique

Research on wireless communication is on the rise due to its capability in improving communication in terms of spectrum efficiency, power and communication reliability. In wireless network, power is consumed mostly in the process of data transmission, hence, the need for cooperative relay protocol and technique to improve systems’ performance through power management and quality of service (QoS). Although, there are various cooperative protocols which include: amplify-and-forward, decode-and-forward among others. However, by using these cooperative protocols, the amount of power consumed and QoS still require improvement. Thus, in this work the quest for incorporation of Maximal Ratio Combining (MRC) technique with the Decode-and-Forward (DF) relay protocol in cooperative network. The cooperative network with DF protocol considered consists of the source, destination and relay(s) nodes. The MRC was incorporated at the destination just to combine the received signals from the relay nodes. Moreover, the system’s simulation was carried out by using MATLAB R2020a and evaluated using bit error rate and power consumption as the performance metrics. The obtained results showed that the QoS and power consumption of the considered cooperative network was considerably improved when MRC was employed in the network in comparison with an existing work.

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.

Virtual full-duplex buffer-aided relay selection schemes for secure cooperative wireless networks

This paper considers secure communication in buffer-aided cooperative wireless networks in the presence of one eavesdropper, which can intercept the data transmission from both the source and relay nodes. It is assumed that the relays employ the randomize-and-forward (RF) strategy such that the eavesdropper can only decode the signals received in the two hops independently. Two cooperative secure transmission schemes, i.e., hybrid imitating full-duplex max-max-ratio relay selection (HyIFD) scheme and threshold-based link selection (TBLS) scheme are proposed for adaptive- and fixed-rate transmissions aiming at improving the secrecy throughput and secrecy outage probability, respectively. For adaptive-rate transmissions (ART), the proposed scheme switches among three sub-strategies according to different conditions such as the number of relays and transmit power. Different relays are chosen for reception and transmission according to the ratio of the legitimate channels to the eavesdropper channels to imitate the full-duplex transmission mode. For fixed-rate transmissions (FRT), a hybrid HD/FD transmission mode is designed to increase the transmission probabilities of two hops under the transmission quality constraint. Two parameters are introduced and optimized to minimize the secrecy outage probability. A sub-optimal TBLS (SO-TBLS) scheme is also given. Theoretical analysis of the secrecy throughput and the secrecy outage probability are provided and the closed-form expressions are derived, and verified by numerical results. It is shown that the proposed schemes outperform benchmark schemes in terms of secrecy throughput and secrecy outage probability.

Communication Audio and Video Coding and Decoding Methods in Wireless Cooperative Communication Network

Wireless communication is ubiquitous in people’s daily life. As people’s requirements for wireless communication continue to increase, how to improve system performance has become a core issue that communication researchers pay attention to. Wireless cooperative communication is considered to be a key technology in the future communication system because it can provide better communication quality, higher system capacity, wider communication coverage, richer services, and high spectrum utilization efficiency. The proposed network coding can effectively eliminate the transmission bottleneck problem faced by wireless cooperative communication. The development of audio and video communication coding technology has increased the demand for audio and video communication services. The goal of audio and video coding is shifting from traditional storage applications to network transmission. Therefore, the audio and video coding technology for network transmission is being affected by academia and industry. The purpose of this paper is to study the communication audio and video codec methods in wireless cooperative communication networks and to understand the development status of audio and video codec by reading a large number of related documents. On the basis of the problem, relevant experiments are designed to conduct in-depth research. Experimental results show that this scheme can simplify the implementation of scalable coding, improve the coding efficiency of the enhancement layer, and improve the quality of the reconstructed video when the audio and video streams are truncated.

Low Complexity Joint Sub-Carrier Pairing, Allocation and Relay Selection in Cooperative Wireless Networks

Multi-carrier cooperative relay-based wireless communication is of particular interest in future wireless networks. In this paper we present resource allocation algorithm in which sub-carrier pairing is of particular interest along with fairness constraint in multi-user networks. An optimization of sub-carrier pair selection is formulated through capacity maximization problem. Sub-carrier pairing is applied in both two-hop Amplify & Forward (AF) and Decode & Forward (DF) cooperative multi-user networks. We develop a less complex centralized scheme for joint Sub-carrier pairing and allocation along with relay selection. The computational complexity of the proposed algorithms has been analyzed and performance is compared with Exhaustive Search Algorithm.

Federated Meta-Learning Enhanced Acoustic Radio Cooperative Framework for Ocean of Things

Ocean of Things, consisting of multiple buoys distributed on the sea, is an acoustic radio cooperative wireless network that aims to acquire underwater information. In this paper, a deep neural network (DNN)-based receiver with data augmentation, termed chirp (C)-DNN, is developed for a buoy that uses chirp modulation-based underwater acoustic communications. To further solve the problem that the training data at a single buoy may not be sufficient, a federated meta-learning (FML) scheme is proposed to train the DNN-based receiver by exploiting the model parameters from multiple buoys. We analyze the convergence performance of FML and derive a closed-form expression for the convergence rate, accounting for the impacts of scheduling ratios, local epochs, and data volumes on a single node. Simulation results show that the proposed C-DNN receiver that is trained with sufficient data achieves better bit error rate performance and lower complexity than classical matched filter (MF)-based detectors. The proposed FML also outperforms the MF-based method after several communication rounds and achieves better generalization performance than federated learning based systems.

Relay selection schemes for SWIPT-enabled cooperative wireless networks with partial CSI

This study investigates the problem of relay selection in a cooperative network with Nakagami-m fading channels, where the energy of the relays is solely replenished by simultaneous wireless information and power transfer (SWIPT). Two efficient relay selection algorithms which require partial channel state information (CSI) at the source are proposed. The first scheme selects a relay based on the fading channel qualities of the source-relay and the relay-destination. The second one selects a relay based on the harvested power at relay and the fading channel quality of the relay-destination. In terms of coverage probability, the latter scheme is superior and is shown to have a performance close to that of the optimal relay selection scheme. Furthermore, the analytical performance bounds for the two proposed schemes are formulated. The performance analysis along with the simulation results are presented, demonstrating the superiority of the proposed schemes over the existing algorithms.

Comparison of Various Techniques with PSO based Power Allocation Strategy in Cooperative Wireless Networks

Abstract: Now a days, wireless communication using co-operative networks have attracted many attentions due to its suitability of working in different environments with acceptable performances. During the transmission, a major requirement of optimal power allocation strategy is observed and this is the major concern of many researchers. This power allocation technique requires a suitable optimization algorithm while selecting the power allocation factor for power assignment. In the paper various optimization strategies are compared with proposed particle swarm optimization technique. A cooperative communication frame work is used with amplify and forward as relaying technique. The proposed algorithm using the tech-nique is simulated and the comparison results are obtained. Simulation results when compared outperformed with other previous works. Keywords: Cooperative networks; optimal power alloca-tion; Amplify and forward relaying; Particle Swarm Opti-mization (PSO).

Performance on Multiple Pilot-Based Grouping Methods in Satellite-Terrestrial Cooperative Wireless Networks

The grouping method is an efficient transmitting strategy in a spatial diversity system. In this paper, relay-based grouping methods in satellite terrestrial cooperative wireless networks are proposed. The proposed methods focus on finding out the best two signals received from relay stations in a user’s neighborhood and use the advantage of space diversity to overcome the effect of channel fading. A grouping method, called the pilot-based grouping method was proposed in our previous work. In order to improve the grouping success rate and the channel capacity, a modified grouping method is proposed. In addition, for a single relay the modified grouping method can achieve better results than the pilot-based grouping method. In the end, several analysis strategies of the grouping method for multimedia broadcast and multicast services in satellite terrestrial cooperative networks are proposed. The simulation results show the performance improvement and the system evaluation for different quality of services in the demanded relay-based cooperative networks. The proposed modified grouping methods can be widespread in any relay-based cooperative networks.

Optimal power allocation for a wireless cooperative network with UAV.

The main objective of this work was to investigate the optimal power allocation strategy in the UAV cooperative wireless Decode and Forward (DF) relay network. Firstly, the outage probability of the system with and without diversity gain was derived. Two optimization problems were studied for different application scenarios. One of the optimization problems sought to determine an optimal power allocation strategy in certain total power constraint to minimize the system outage probability. Since the optimization problem we established is convex, the Lagrange multiplier method was adopted. For the system without diversity, the explicit expression of the optimal power allocation was derived. The relationship between UAV transmission power and source node transmit power was obtained for the diversity gain system and then the Newton iterative method was used to obtain the optimal power allocation method. The simulation results show that the optimal power allocation strategy can reduce the outage probability of the system under the same conditions, and the reliability of the system was improved. Another optimization problem aimed to use the lowest power to ensure that the outage probability within a certain specific threshold for saving energy resources. Because the optimization problem is non-convex, we proposed an effective method to solve the optimal power allocation strategy. Similarly, we derived the closed-form solution of the power allocation strategy for the system without diversity. Finally, the simulation results verify the correctness of the proposed algorithm.

The generalized join the shortest orbit queue system: stability, exact tail asymptotics and stationary approximations

We introduce the generalized join the shortest queue model with retrials and two infinite capacity orbit queues. Three independent Poisson streams of jobs, namely a smart, and two dedicated streams, flow into a single-server system, which can hold at most one job. Arriving jobs that find the server occupied are routed to the orbits as follows: Blocked jobs from the smart stream are routed to the shortest orbit queue, and in case of a tie, they choose an orbit randomly. Blocked jobs from the dedicated streams are routed directly to their orbits. Orbiting jobs retry to connect with the server at different retrial rates, i.e., heterogeneous orbit queues. Applications of such a system are found in the modeling of wireless cooperative networks. We are interested in the asymptotic behavior of the stationary distribution of this model, provided that the system is stable. More precisely, we investigate the conditions under which the tail asymptotic of the minimum orbit queue length is exactly geometric. Moreover, we apply a heuristic asymptotic approach to obtain approximations of the steady-state joint orbit queue-length distribution. Useful numerical examples are presented and shown that the results obtained through the asymptotic analysis and the heuristic approach are agreed.