Cooperative Wireless Communication Research Articles

UAV-Assisted Wireless Cooperative Communication and Coded Caching: A Multiagent Two-Timescale DRL Approach

UAV-Assisted Wireless Cooperative Communication and Coded Caching: A Multiagent Two-Timescale DRL Approach

Best Relay Selection Scheme in Wireless Cooperative Communication

In this research, the combination of the relay selection and network coding is used to measure the performance in LOS and NLOS condition over cooperative communication. The research aims are to select the best relay as assisted relay as well as to improve performance system. The research method used four nodes, two nodes as source and destination and two nodes as relays. The single relay selection is used to select best relay of several relays. Measurements are conducted by altering the positions of the relays to achieve optimal outcomes. The findings indicate that the relay with the lowest Bit Error Rate (BER) and the shortest distance is chosen. The study's outcomes, when measuring throughput, reveal that network coding throughput is 21.8% higher than that without network coding in Non-Line of Sight (NLOS) conditions. In Line of Sight (LOS) conditions, the throughput is increased by 23%.

Overview of Tensor-Based Cooperative MIMO Communication Systems-Part 1: Tensor Modeling.

Due to increasingly strong and varied performance requirements, cooperative wireless communication systems today occupy a prominent place in both academic research and industrial development. The technological and economic challenges for future sixth-generation (6G) wireless systems are considerable, with the objectives of improving coverage, data rate, latency, reliability, mobile connectivity and energy efficiency. Over the past decade, new technologies have emerged, such as massive multiple-input multiple-output (MIMO) relay systems, intelligent reflecting surfaces (IRS), unmanned aerial vehicular (UAV)-assisted communications, dual-polarized (DP) antenna arrays, three dimensional (3D) polarized channel modeling, and millimeter-wave (mmW) communication. The objective of this paper is to provide an overview of tensor-based MIMO cooperative communication systems. Indeed, during the last two decades, tensors have been the subject of many applications in signal processing, especially for digital communications, and more broadly for big data processing. After a brief reminder of basic tensor operations and decompositions, we present the main characteristics allowing to classify cooperative systems, illustrated by means of different architectures. A review of main codings used for cooperative systems is provided before a didactic and comprehensive presentation of two-hop systems, highlighting different tensor models. In a companion paper currently in preparation, we will show how these tensor models can be exploited to develop semi-blind receivers to jointly estimate transmitted information symbols and communication channels.

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

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

Path Loss and Auxiliary Communication Analysis of VANET in Tunnel Environments

Vehicular ad hoc network (VANET) communications face severe fading problems due to the signal reflections and diffractions within tunnels. Unlike the open road, the space of a tunnel is very limited, so VANET communication performance in a tunnel is seriously affected. In the process of signal transmission, the reflected signal is symmetrical with the incident signal after it is reflected by the road and the wall. In this paper, we establish a mathematical model of path loss for V2V (Vehicle-to-Vehicle) communication based on the principle of signal reflection symmetry in tunnels and considering several factors, such as the tunnel surface and the color of the tunnel wall. In addition, we use cooperative communication to form a virtual multiple-input multiple-output (V-MIMO) system, to improve the communication quality in tunnels. In the proposed system, the OBU (On-Board-unit) and RSU (Road-Side-Unit) share each other’s antennas, so that wireless cooperative communication can be employed, without increasing the number of antennas in a one-way tunnel. Therefore, this multipath fading internal electromagnetic wave propagation model can be used to improve performance. A deep reinforcement learning algorithm was used to solve the pairing problem to obtain a more accurate OBU and RSU pair, to form a V-MIMO system. Here, the RSU is regarded as an agent and interacts with the OBU in the tunnel. The optimal strategy was learned in a real-time changing simulation environment, and the experiment verified the convergence of the algorithm. The simulation results showed that, compared with the Q-learning based scheme, the optimal matching algorithm based on V-MIMO and a DQN (Deep Q-network) could effectively reduce the probability of transmission outages and improve the communication efficiency in tunnels.

Innovative Data-Driven Analysis of Water Management for Effective Agricultural Practices

Objective: To measure, investigate, analyse variables and factors that influences water resources management as used in the agricultural sector, and how water management techniques, systems, decision making processes can be optimized for a more efficient and effective water-agriculture-food nexus. Methods: Using current and historical real world data from validated open source data stores; analysis was carried out on agricultural, socio-economic, demographic, geo-climatic, gender, wireless technological factors and variables; that influence available and needed water capacity for farming (Wc) in selected African Countries and Globally. The methodical and data-driven analyses were carried out using Analytics, Machine Learning and Wireless Cooperative Communications algorithms. Results: The available and needed water capacity for farming (Wc) was calculated and predicted using factors and independent variables of real world data that were shown to influence Wc, and that were statistically measured and analysed. Time based, qualitative, quantitative, predictive, simulative, clustering, statistical data analyses confirmed that available water resources, socio-economy, demography, agricultural factors, Gender diversity & inclusion, Climate Change and Wireless Communication technologies; can influence water availability and water management for agriculture. Conclusion: Modern data-driven, cost effective analytical processes can be used to productively analyse and develop strategies, processes, systems and technologies for innovative, efficient and effective water management for improved agricultural practices and a sustainable environment.

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.

Harvest-on-Sky: An AoI-Driven UAV-Assisted Wireless Communication System

The 5G cellular network provides a sufficient data rate to support the ever growing number of devices that will be connected to the Internet. To enable Internet of Things (IoT) applications in remote locations, it is very crucial to increase the coverage of the cellular networks. This article proposes a wireless communication system that exploits a full-duplex enabled unmanned aerial vehicle (FD-UAV) integrated into a communication network as a mobile relay to expand network coverage. With the deployment of IoT devices, a large volume of data is introduced into the network, causing a delay in data delivery due to scarcity of resources. Real-time information updates play an important role in modern IoT applications including connected vehicles in intelligent transportation systems, digital healthcare, real-time tracking, and so on. Decision making based on the latest fresh information is critically important for these applications. We quantify the freshness of data in IoT applications using a new performance metric, the age of information (AoI). This work proposes a new mathematical model to estimate the average AoI (AAoI) in the FD-UAV assisted cooperative wireless communication system. Here, sensors located in a transport infrastructure harvest energy from radio frequency (RF) signals transmitted by the FD-UAV via a wireless power transmission RF energy harvesting (EH) technique. Then sensors consume this energy to transmit their sensed real-time observations to the access point with the aid of FD-UAV. A closed-form expression for the AAoI is derived as a function of time allocated for energy harvesting. The optimal time allocation for EH that minimizes the AAoI is identified together with the effect of self-interference experienced by the UAV.

Improved Bi-Directional Three-Phase Single-Relay Selection Technique for Cooperative Wireless Communications

Single-relay selection techniques based on the max-min criterion can achieve the highest bit error rate (BER) performance with full diversity gain as compared to the state-of-the-art single-relay selection techniques. Therefore, in this work, we propose a modified max-min criterion by considering the differences among the close value channels of all relays while selecting the best relay node. The proposed criterion not only enjoys full diversity gain but also offers a significant improvement in the achievable coding gain as compared to the conventional one. Basically, in this article, an improved bi-directional three-phase single-relay selection technique using the decode-and-forward protocol for wireless cooperative communication networks that enhances the overall network performance in terms of BER is proposed and its performance is proved analytically and through Monte-Carlo simulations. More specifically, the proposed criterion is first used to select the best relay-node. After that the selected relay-node forwards the information symbols of the communicating terminals after performing a digital network coding to minimize power consumptions. In our simulations, we show that our proposed technique outperforms the best-known single relay selection techniques. Furthermore, we prove that the BER results obtained from our conducted simulations perfectly match those obtained from the theoretical analysis.

Joint Relay Selection and Adaptive Modulation and Coding for Wireless Cooperative Communications

This paper considers a wireless cooperative communication system with the adaptive modulation and coding (AMC). We take the joint relay and AMC mode selection as two time-scales of optimization problems, which aim at maximizing the achievable data rate. We treat the best relay selection as a long-term objective and the best AMC mode selection as a short-term objective, to limit the signaling overhead for the wireless communication system. However, the evaluation of the achievable data rate for any of relay and AMC mode combinations needs the estimation of the wireless channel. To this end, we propose an online optimization-while-estimation algorithm based on discrete stochastic approximation to jointly solve both the relay and AMC selection problems. The algorithm requires only per-frame channel sampling and estimation in each algorithm iteration, and approaches the optimal achievable data rate asymptotically. Simulation results show that our proposed algorithm can quickly converge to the maximum achievable data rate.

Effect of controlling maximum-SNR-based relay selection strategy in cooperative wireless communication systems

<span>Relay selection strategy under maximum-signal-to-noise ratio (MAX-SNR) criterion was proven to maximize performance but at the expense of losing fairness among the cooperative relays. In this work, the effect of controlling the MAX-SNR criterion on the spectral efficiency of cooperative wireless communication system with adaptive modulation is investigated. Specifically, the probability density function (PDF) of the end-to-end SNR for the considered system is derived when the controlled selection criterion is considered. Base on that PDF, the average spectral efficiency is then derived and investigated. The results show how the spectral efficiency of the system deteriorates as controlling the selection of a relay. Furthermore, the results of Monte Carlo simulation validate the derived expression.</span>

Improved two-way double-relay selection technique for cooperative wireless communications

In this article, a novel two-way double-relay selection strategy with its bit error rate (BER) performance analysis is proposed. In this novel strategy, as a first step we choose two relays out of a set of relay-nodes in a way to maximize the system performance in terms of BER and complexity. In the second step, the selected relays apply orthogonal space-time coding scheme using the three-phase protocol to establish a two-way communication between the transceivers, which will lead to a significant improvement in the achievable diversity and coding gain with a very low decoding complexity by using a symbol-wise decoder. Furthermore, the performance of the overall system is further enhanced through the use of a network coding method at the selected relay-nodes. Moreover, this paper proposes the analytical approximation of the BER performance. As well, we show that the analytical results match perfectly the simulated ones. In addition, we prove that our strategy outperforms the current state-of-the-art ones by proposing a better cooperative communication system in terms of BER.

Relay Selection Scheme Enhancing Reliability Based on MIMO-OFDM System

In this paper, a relay selection scheme is proposed in the Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system. The conventional relay selection schemes in the wireless cooperative communication system have high implementation complexity and overhead. The proposed scheme is an adaptive relay selection scheme using Singular Value Decomposition (SVD) to select a relay with channel coefficients that maximize channel capacity. Proposed scheme uses combining factor with singular value in order to combine received signal. Simulation result shows that the proposed scheme improves the Bit Error Rate (BER) performance, compared with the conventional schemes. The proposed scheme with combining factors has enhanced BER performance than the conventional schemes.

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.

Combining Power Allocation and Superposition Coding for an Underlay Two-way Decode-and-forward Scheme

Combining Power Allocation and Superposition Coding for an Underlay Two-way Decode-and-forward Scheme

Analyzing bit error rate of relay sensors selection in wireless cooperative communication systems

Cooperative communication systems, which make use of the intermediate relays between the transmitter and the receiver, have been employed as an effective technique to combat the channel fading and to enhance system performance. Cooperative systems have some drawbacks such as high latency and may diversity order not guaranteed. To alleviate the negative effects of these factors, the relay selection protocol is employed in cooperative communication systems to increase overall cooperative system performance. Relay selection in the cooperative systems enables the source to cooperate with the single relay node rather than multiple relay nodes which guaranteed the diversity order.

Joint relay selection and energy harvesting to improve performance of cooperative communication systems

This paper focuses on a combining relay selection with energy harvesting (EH), known as joint relay selection with EH (JRSEH), to improve performance in wireless cooperative communication systems. Previous research was examined performance improvement with relay selection (RS) techniques without combined with EH (RS non-EH). This study aims to improve the performance by applying EH and the RS in the cooperative communication system. In the system, a source selects the best relay from several relays that produce the highest SNR value at the destination. The selected best relay performs EH based on time switching. Then, the best relay with EH obtains the power to forward information to the destination using the Amplify and Forward (AF) relay scheme. The channel from source to relay is Rician fading, and from the relay to a destination is Rayleigh fading. The research method used is system modeling and analysis of computer simulations. The system performance is calculated based on the bit error rate (BER) and the throughput in a multi-relay cooperative system with EH and RS. The results show that the performance of the proposed JRSEH higher than that of RS non-EH, multi-relay EH, and multi-relay non-EH.

Applications of Meijer’s Factorization Theorems in Performance Analyses of All-Optical Multi-Hop FSO Systems

The use of bivariate Fox H-functions (BFHFs) in performance analyses of wireless communication systems has gained considerable attention in past few decades. However, the non-existence of robust built-in routines for evaluating such functions in standard computing systems poses numerous challenges in numerical experiments and simulations. Motivated by the apparent need to circumvent these difficulties in performance analyses of cooperative wireless communications, this work presents an alternative method for obtaining the exact, approximate and asymptotic BFHF-free cumulative distribution function (CDF) of the end-to-end (e2e) signal-to-noise ratio (SNR) of multi-hop amplify-and-forward (AF) relaying wireless communication systems. As an illustration, the e2e performance analysis of an all-optical dual-hop free-space optical (FSO) transmission system over Gamma-Gamma turbulence in the presence of pointing errors is revisited. Specifically, new mathematical formulae for the statistical characteristics of the e2e SNR for systems with AF fixed-gain relaying as well as channel-state-information(CSI)-assisted using heterodyne detection (HD) or intensity modulation with direct detection (IM/DD) are derived in terms of mathematically malleable and uniformly convergent infinite series of weighted Meijer G-functions. The usefulness of the derived CDFs is illustrated through derivation of traditional system performance metrics. The accuracy of the derived analytical formulae is verified via Monte Carlo simulations in MATLAB®. Finally, based on results observed in this paper, useful expansions of common BFHFs in terms of easily computable univariate hypergeometric functions are proposed.

Multi objective optimization for performance analysis of Cooperative Wireless Communication

Multi objective optimization for performance analysis of Cooperative Wireless Communication

Age of Information in SWIPT-Enabled Wireless Communication System for 5GB

With the advancements in real-time applications, age of information (AoI) emerges to describe the freshness of data. Here, we investigate AoI performance metric in simultaneous wireless information and power transfer (SWIPT) enabled cooperative wireless communication system. We use two SWIPT protocols: time-switching (TS) and power- splitting (PS) at the relay node and compute the AoI performance. SWIPT has a great potential to energize energy constrained communication nodes in wireless sensor networks (WSNs) and Internet of Things (IoT) applications while maintaining a high degree of Quality-of-Service (QoS). Finally, we discuss the possible future directions in terms of 5G and beyond (5GB) to realize the integration of SWIPT with the enhancement of industrial IoT together with ultra-reliable low latency communication (URLLC) for future 3GPP releases.