Cooperative Wireless 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

Shrimp Pond Monitoring System using Cooperative Wireless Sensor Network Multi-Hop Technique based on Internet of Things

Water quality is a crucial factor in maintaining the survival and growth of shrimp. Manual water quality monitoring in shrimp ponds is no longer effective due to the need for periodic monitoring to maintain stable water quality. Therefore, online monitoring using various sensors installed in each pond is necessary. However, there are several challenges to overcome, such as the large expanse of the shrimp ponds, which may lead to data loss due to signal disruptions, and limited energy to power the sensors. To address these issues, this paper proposes the cooperative Wireless Sensor Network (WSN) technique with a multi-hop method for communication in the monitoring process. The system consists of five sensor nodes: temperature sensor, pH sensor, water level sensor, intake water flow sensor, and drain water flow sensor. The cooperative WSN multi-hop technique helps reduce energy consumption in the sensor nodes during measurement and data transmission, while also preventing data packet loss. This is achieved through the use of relay nodes that strengthen signals and forward data to the sink node. As a result, the battery life is extended, and energy usage in the monitoring process can be optimized. The system enables real-time online monitoring and can be accessed through a smartphone application. The results of this study show that the total energy consumption for data transmission in the sensor nodes is 9.64 J, while the total energy consumption for data forwarding in the relay nodes is 9.15 J. The total energy consumption in the transmit and receive processes is 18.79 J or 5.2 mWh. Therefore, it can be concluded that the energy savings of the proposed system is 4.3 mWh or approximately 45%, and is more efficient than the previous system.

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%.

Development of data power control algorithms for downlink transmission in cooperative Wireless Body Area Networks

Development of data power control algorithms for downlink transmission in cooperative Wireless Body Area Networks

Destination-Feedback Free Distributed Transmit Beamforming Using Guided Directionality

Distributed transmit beamforming enables cooperative radios to act as one virtual antenna array, extending their communications’ range beyond the capabilities of a single radio. Most existing distributed beamforming approaches rely on the destination radio sending feedback to adjust the transmitters’ signals for coherent combining. However, relying on the destination radio’s feedback limits the communications range to that of a single radio. Existing destination-feedback-free approaches rely on phase synchronization and knowing the node locations with sub-wavelength accuracy, which becomes impractical for radios mounted on high-mobility platforms like UAVs. In this work, we propose and demonstrate a destination-feedback-free distributed beamforming approach that leverages the radio’s mobility and coarse location information in a dominant line-of-sight channel. In the proposed approach, one radio acts as a guide and moves to point the beam of the remaining radios towards the destination. We specify the radios’ position requirements and verify their relation to the combined signal at the destination using simulations. A proof of concept demo was implemented using software defined radios, showing up to 9 dB SNR improvement in the beamforming direction just by relying on the coarse placement of four radios.

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.

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

Listening is Action: A Soundwalk with Hildegard Westerkamp

In the sound documentary Listening is Action, the composer Hildegard Westerkamp engages in a conversation with Luis Velasco-Pufleau at her home in the city of Vancouver, which is situated on the traditional, ancestral, and unceded territories of the xʷməθkʷəy̓əm (Musqueam), Sḵwx̱wú7mesh (Squamish), and səlilwətaɬ (Tsleil-Waututh) Nations. She talks us through her first field recordings and her soundwalking practice, her work at the Vancouver Co-operative Radio, and her participation in the World Soundscape Project, all of which started or took place in the 1970s. Furthermore, she takes us on soundwalks at places she used to go and record more than thirty years ago, such as those now called Kitsilano Beach and Vancouver’s Downtown Eastside, and that constitute the sources for her soundscape works A Walk Through the City (1981) and Kits Beach Soundwalk (1989). This sound documentary is an invitation to listen more attentively to the multiple voices that inhabit our environments in order to imagine new, plural, and unforeseen realities. The sound work Listening is Action is enhanced by a written commentary in which Luis Velasco-Pufleau explores the radical relationality of listening and the connection between Westerkamp’s thinking with the work of Pauline Oliveros and Hannah Arendt. Finally, he engages with critical listening positionality in order to reflect on some of the limits and contradictions present in the sound documentary.

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.

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.

Improvement of Interfered Cooperative Radio Systems by Applying Alamouti 2×1 Codes

Improvement of Interfered Cooperative Radio Systems by Applying Alamouti 2×1 Codes

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.

QR Decomposition-Based Cyclic Prefixed Single-Carrier Transmissions for Cooperative Communications: Concepts and Research Landscape

As an alternative transmission scheme to orthogonal frequency division multiplexing (OFDM), cyclic prefixed single-carrier (CP-SC) transmissions have been widely adopted to overcome the shortcomings of OFDM. How to exploit the achievable full diversity in frequency selective fading channels is the key question in applying CP-SC-based transmissions. Thus, in this tutorial, we focus on recent research in the areas related to CP-SC transmissions for cooperative wireless systems. After explaining the basic concept and operation of CP-SC transmissions, we introduce various types of diversity that are achievable by CP-SC transmissions. To achieve these types of diversity, it is necessary to employ QR decomposition (QRD)-M-based data detection in the receiver. To verify the benefits of CP-SC transmissions in terms of diversity gain, we exemplify various wireless systems for relaying, spectrum sharing, physical layer security, and distributed cyclic delay diversity, and provide link-level simulations. Especially, as alternative metrics of reliability, which is one of the key features of 5G and beyond 5G (B5G) systems, we evaluate the average symbol error rate and outage probability. Finally, we discuss potential research directions involving CP-SC transmissions in emerging wireless communication systems.

SWIPT-Enabled Cooperative Wireless IoT Networks With Friendly Jammer and Eavesdropper: Outage and Intercept Probability Analysis

SWIPT-Enabled Cooperative Wireless IoT Networks With Friendly Jammer and Eavesdropper: Outage and Intercept Probability Analysis

Distance Distributions and Coverage Probabilities in Poisson-Delaunay Triangular Cells With Application to Coordinated Multipoint Wireless Power Transfer

This paper investigates the power coverage probability in cooperative wireless powered communication networks, where multiple access points collaborate to meet the energy demands of low-power devices. Based on the theory of Poisson-Delaunay triangulation, the probability density functions (PDF) of the Euclidean distance between the access points of the Poisson-Delaunay triangular cell and typical devices are derived. By using the theory of stochastic geometry and the obtained PDFs, the closed-form expressions of the wireless power coverage probability are obtained for three typical locations of the devices. As the wireless power coverage probability expressions involve the extended generalized multivariate MeijerG function (EGMMGF), a new implementation enabling numerical calculation of the EGMMGF is also proposed. The impacts of the main network parameters on the performance of the proposed framework are analyzed. In particular, comparative results show the significant gains that can be achieved in the wireless power coverage when multiple access points participate in the wireless power transfer or when the density of the network’s access points is increased, as compared to the non-cooperative scheme.

Bit Error Rate Analysis of Physical Layer Network Coding Spatially Modulated Full-Duplex Nodes Based Bidirectional Wireless Relay Network

In this paper, Physical Layer Network coding (PLNC)-Spatially Modulated Full-Duplex (SMFD) nodes based two-way/bidirectional cooperative wireless relay network is proposed. The PLNC-SMFD-based system is a viable technology in the field of next-generation wireless networks to enhance spectral efficiency. In the proposed system model, both the source nodes and relay nodes are employed with 2 × 2 antenna configurations where 2 bits of information are exchanged between the source nodes through a relay node. Transmit antenna selection at the source nodes is based on the incoming bitstreams. For instance, the transmit antenna is selected at PLNC-SMFD nodes based on the data symbols of the Most Significant Bit (MSB). Whereas the selected transmit antenna sends the Least Significant Bit (LSB) bit of data symbol at any time instance. Further, the self-interference at the transmitting and receiving nodes is modeled as Gaussian with the thermal noise power as a variance. The Bit Error Rate (BER) analytical expressions for both the upper and lower bound are derived in a Rayleigh Fading channel background. It has been graphically shown that the BER performance of the proposed system analyzes the effect of self-interference.

Lifetime Enhancement of Cooperative Wireless Ad-Hoc Networks using Optimal Power Allocation and Relay Selection Scheme

Cooperative Communication (CC) has greatly reduced the effect of multipath fading, thereby improving the quality of transmitted signals in wireless ad-hoc networks. However, existing works on CC suffers from degradation of network lifetime due to inaccurate selection of the optimal relay terminal. This results in frequent battery recharging due to high energy consumed and battery depletion. Hence, in this paper, lifetime enhancement of cooperative wireless ad-hoc networks is carried out using allocated optimal power and relay selection scheme to ensure an optimal selection of the best relay by balancing and conserving the energy consumption of the nodes. Transmit power optimization problems were formulated for Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying strategies to obtain the optimal power allocations required to transmit the information. The proposed scheme named Energy-Aware Relay Selection (EARS) was simulated in MATLAB software environment and average network lifetime performance evaluation was performed. The result obtained shows that the proposed EARS improves the network performance by 10.06% and 3.56% for AF and DF relaying strategies, respectively over the existing power-aware relay selection schemes.

Decision Feedback Modulation Recognition with Channel Estimation for Amplify and Forward Two-Path Consecutive Relaying Systems.

Automatic modulation recognition (AMR) is an essential component in the design of smart radios that can intelligently communicate with their surroundings in order to make the most efficient use of available resources. Throughout the last few decades, this issue has been subjected to in-depth examination in the published research literature. To the best of the authors’ knowledge, there have only been a few studies that have been specifically devoted to the task of performing AMR across cooperative wireless transmissions. In this contribution, we examine the AMR problem in the context of amplify-and-forward (AAF) two-path consecutive relaying systems (TCRS) for the first time in the literature. We leverage the property of data redundancy associated with AAF-TCRS signals to design a decision feedback iterative modulation recognizer via an expectation-maximization procedure. The proposed recognizer incorporates the soft information produced by the data detection process as a priori knowledge to generate the a posteriori expectations of the information symbols, which are employed as training symbols. The proposed algorithm additionally involves the development of an estimate of the channel coefficients as a secondary activity. The simulation outcomes have validated the feasibility of the proposed design by demonstrating its capacity to achieve an excellent recognition performance under a wide range of running conditions. According to the findings, the suggested technique converges within six rounds, achieving perfect recognition performance at a signal-to-noise ratio of 14 dB. Furthermore, the minimal pilot-to-frame-size ratio necessary to successfully execute the iterative procedure is 0.07. In addition, the proposed method is essentially immune to time offset and performs well throughout a broad range of frequency offset. Lastly, the proposed strategy beats the existing techniques in recognition accuracy while requiring a low level of processing complexity.