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Lan, Tingting, Danyang Qin i Guanyu Sun. "Joint Optimization on Trajectory, Cache Placement, and Transmission Power for Minimum Mission Time in UAV-Aided Wireless Networks". ISPRS International Journal of Geo-Information 10, nr 7 (23.06.2021): 426. http://dx.doi.org/10.3390/ijgi10070426.
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In recent years, due to the strong mobility, easy deployment, and low cost of unmanned aerial vehicles (UAV), great interest has arisen in utilizing UAVs to assist in wireless communication, especially for on-demand deployment in emergency situations and temporary events. However, UAVs can only provide users with data transmission services through wireless backhaul links established with a ground base station, and the limited capacity of the wireless backhaul link would limit the transmission speed of UAVs. Therefore, this paper designed a UAV-assisted wireless communication system that used cache technology and realized the transmission of multi-user data by using the mobility of UAVs and wireless cache technology. Considering the limited storage space and energy of UAVs, the joint optimization problem of the UAV’s trajectory, cache placement, and transmission power was established to minimize the mission time of the UAV. Since this problem was a non-convex problem, it was decomposed into three sub-problems: trajectory optimization, cache placement optimization, and power allocation optimization. An iterative algorithm based on the successive convex approximation and alternate optimization techniques was proposed to solve these three optimization problems. Finally, in the power allocation optimization, the proposed algorithm was improved by changing the optimization objective function. Numerical results showed that the algorithm had good performance and could effectively reduce the task completion time of the UAV.
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Wei, Menghan, Youjia Chen i Ming Ding. "On the Performance of UAV-Aided Content Caching in Small-Cell Networks with Joint Transmission". Electronics 10, nr 9 (28.04.2021): 1040. http://dx.doi.org/10.3390/electronics10091040.
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Unmanned aerial vehicles (UAVs), featured by the high-mobility and high-quality propagation environment, have shown great potential in wireless communication applications. In this paper, a novel UAV-aided small-cell content caching network is proposed and analyzed, where joint transmission (JT) is considered in the dense small-cell networks and mobile UAVs are employed to shorten the serving distance. The system performance is evaluated in terms of the average cache hit probability and the ergodic transmission rate. From the analytical results, we find that (i) the proposed UAV-aided small-cell network shows superior caching performance and, even with a small density of UAVs the system’s cache hit probability, can be improved significantly; (ii) the content’s optimal caching probability to maximize the cache hit probability is proportional to the (K+1)-th root of its request probability, where K is the number of small-cell base stations that serve each user by JT; (iii) caching the most popular content in UAVs may lead to a low transmission rate due to the limited resource offered by the low-density UAVs. Simulation results are presented to validate the theoretical results and the performance gain achieved by the optimal caching strategy.
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Le, Anh-Tu, Nhan Duc Nguyen, Dinh-Thuan Do i Munyaradzi Munochiveyi. "Enabling Device-to-Device Transmission for NOMA-Aided Systems". Wireless Communications and Mobile Computing 2021 (16.11.2021): 1–10. http://dx.doi.org/10.1155/2021/4342983.
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To utilize the close transmission, we assume that the device-to-device (D2D) link is activated to improve the performance of the far user. We consider two groups of users in the nonorthogonal multiple access- (NOMA)- aided wireless system. These features are necessary for massive connectivity in future wireless systems. The system performance also shows suitable performance at far distance users. To evaluate the performance in detail, we derive novel closed form expressions of outage probability. In practical situations impaired by channel uncertainty, it is necessary to evaluate the impact of channel error levels on outage probability. Our numerical results indicated that the transmit power at the base station and channel error level are the main impacts on system performance. Despite these impacts, our obtained numerical results demonstrated that the proposed scheme can still increase energy efficiency and achieve significant outage performance via many practical challenges.
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Ren, Yuan, Yixuan Tan, Meruyert Makhanbet i Xuewei Zhang. "Improving Physical Layer Security of Cooperative NOMA System with Wireless-Powered Full-Duplex Relaying". Information 12, nr 7 (10.07.2021): 279. http://dx.doi.org/10.3390/info12070279.
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Non-orthogonal multiple access (NOMA) and wireless energy harvesting are two promising technologies for improving spectral efficiency and energy efficiency, respectively. In this paper, we study the physical layer security of a wireless-powered full-duplex (FD) relay-aided cooperative NOMA system. In particular, the source is wiretapped by an eavesdropper, and the FD relay assists the transmission from the source to a near user and a far user with self-energy recycling. To enhance the security performance of the system, we propose an artificial noise (AN)-aided cooperative transmission scheme, in which the relay emits a jamming signal to confuse the eavesdropper while receiving the signal from the source. For the proposed scheme, the ergodic secrecy sum rate (ESSR) is derived to characterize the secrecy performance and a lower bound of ESSR is obtained. Finally, numerical results verify the accuracy of the theoretical analysis of the proposed AN-aided secure transmission scheme. The superiority of the proposed scheme is also demonstrated since this scheme can achieve better secrecy performance, compared to the conventional cooperative NOMA scheme.
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Nguyen, Nhan Duc, Anh-Tu Le, Munyaradzi Munochiveyi, Fatemeh Afghah i Evangelos Pallis. "Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware". Electronics 11, nr 6 (14.03.2022): 900. http://dx.doi.org/10.3390/electronics11060900.
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In this article, we investigate the design of reconfigurable intelligent surface (RIS)-aided transmission as a smart method to reflect signals received from access points to users and, hence, improving users’ performance. To implement smart Internet of Things (IoT) networks, massive connectivity and low-cost deployment are essential in designing such systems. In particular, we consider two practical scenarios (dual-hop and single-hop transmissions). These scenarios highlight the potential of RIS in enhancing the system’s outage probability performance. Furthermore, to characterize channel conditions in practice, we pay particular attention to two-channel distributions that are non-central chi-square (NCCS) distributions that approximate the channel distribution of the RIS-aided wireless system and the squared KG distribution. In addition, the RIS-aided system may face imperfect hardware-related issues in practice. Therefore, we need to consider the degraded performance of practical RIS-aided systems by considering the detrimental impact of in-phase and quadrature-phase imbalance (IQI). To characterize the main system performance metric, we provide closed-form formulas of outage probability and ergodic capacity. We then evaluate system performance under the impacts of signal-to-noise ratio (SNR), the number of meta-surfaces, and channel parameters. All closed-form outage expressions are validated via Monte Carlo simulations. Simulation results indicate that the considered RIS scheme at dual-hop and single hop under the impact of IQI and RIS hardware impairment achieves significant improvements in terms of outage probability at high SNR and high meta-surface number N. Additionally, the simulation results demonstrate that the impact of IQI on the proposed system is limited. It is worth noting that, in terms of ergodic capacity, ergodic capacity faces an upper limit. Despite this limitation, the proposed system can still work well once some parameters are controlled well, such as the transmit SNR, levels of IQI, and the number of RIS components.
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Ma, Cong, i Wonjun Chung. "Visual Communication Design Based on Collaborative Wireless Communication Video Transmission". Journal of Sensors 2022 (15.01.2022): 1–11. http://dx.doi.org/10.1155/2022/5348222.
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With the development of wireless communication technology, video and multimedia have become an integral part of visual communication design. Designers want higher interactivity, diversity, humanization, and plurality of attributes in the process of visual communication. This makes the process of visual communication have high requirements for the quality and real-time data transmission. To address the problem of transmitting HD video in a heterogeneous wireless network with multiple concurrent streams to improve the transmission rate and thus enhance the user experience, with the optimization goal of minimizing the system transmission delay and the delay difference between paths, the video sender and receiver are jointly considered, and the video transmission rate and the cache size at the receiver are adaptively adjusted to improve the user experience, and a cooperative wireless communication video transmission based on the control model for video transmission based on cooperative wireless communication is established, and video streams with self-similarity and long correlation are studied based on Pareto distribution and P / P / l queuing theory, based on which an adaptive streaming decision method for video streams in heterogeneous wireless networks is proposed. Simulation results show that the proposed multistream concurrent adaptive transmission control method for heterogeneous networks is superior in terms of delay and packet loss rate compared with the general load balancing streaming decision method, in terms of transmission efficiency and accuracy.
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Chen, Zikang, Ming Zeng i Zesong Fei. "Joint Unmanned Aerial Vehicle Location and Beamforming and Caching Optimization for Cache-Enabled Multi-Unmanned-Aerial-Vehicle Networks". Electronics 12, nr 16 (14.08.2023): 3438. http://dx.doi.org/10.3390/electronics12163438.
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Due to the advantages such as high flexibility, low cost and easy implementation offered by unmanned aerial vehicles (UAVs), a UAV-assisted network is regard as an appealing solution to a seamless coverage, high disaster-tolerant and on-demand wireless system. In this paper, we focus on the downlink transmission in a cache-enabled UAV-assisted wireless communication network, where UAVs cache popular content from a macro base station in advance and cooperatively transfer the content to users. We aim to minimize the average transmission latency of the system and to formulate an optimization problem that jointly optimizes the UAV location, beamforming and caching strategy. However, the formulated problem is very challenging because of its non-convexity and the highly coupled optimization variables. To solve this resulting problem efficiently, we decompose it into two subproblems, namely UAV location and beamforming optimization, and UAV caching strategy optimization. The first subproblem is an NP-hard joint optimization problem, while the second one is a linear programing problem. By adopting the first-order Taylor expansion, we propose a convex optimization algorithm based on the difference-of-convex (DC) method. Specifically, we bring out a method to apply linear approximation in the DC-based algorithm, which is particularly suitable to the problems involving complicated summations. The numerical results demonstrate that the proposed DC-based iterative optimization algorithm can efficiently reduce the average transmission latency of the system.
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Chen, Shupei, Zhigang Chen, Jia Wu i Kanghuai Liu. "An Adaptive Delay-Tolerant Routing Algorithm for Data Transmission in Opportunistic Social Networks". Electronics 9, nr 11 (13.11.2020): 1915. http://dx.doi.org/10.3390/electronics9111915.
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In opportunistic networks, the requirement of QoS (quality of service) poses several major challenges to wireless mobile devices with limited cache and energy. This implies that energy and cache space are two significant cornerstones for the structure of a routing algorithm. However, most routing algorithms tackle the issue of limited network resources from the perspective of a deterministic approach, which lacks an adaptive data transmission mechanism. Meanwhile, these methods show a relatively low scalability because they are probably built up based on some special scenarios rather than general ones. To alleviate the problems, this paper proposes an adaptive delay-tolerant routing algorithm (DTCM) utilizing curve-trapezoid Mamdani fuzzy inference system (CMFI) for opportunistic social networks. DTCM evaluates both the remaining energy level and the remaining cache level of relay nodes (two-factor) in opportunistic networks and makes reasonable decisions on data transmission through CMFI. Different from the traditional fuzzy inference system, CMFI determines three levels of membership functions through the trichotomy law and evaluates the fuzzy mapping from two-factor fuzzy input to data transmission by curve-trapezoid membership functions. Our experimental results show that within the error interval of 0.05~0.1, DTCM improves delivery ratio by about 20% and decreases end-to-end delay by approximate 25% as compared with Epidemic, and the network overhead from DTCM is in the middle horizon.
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, Senthilkumar.S, Devarajan R. "Wireless Aided Protection for 110 KV Transmission Line to Improve the System Stability". International Journal of Innovative Research in Computer and Communication Engineering 4, nr 7 (30.07.2016): 13041–48. http://dx.doi.org/10.15680/ijircce.2016.0407006.
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Moon, Sang-Rok, Seungjun Han, Sanghwa Yoo, Heuk Park, Won-Kyoung Lee, Joon Ki Lee, Jongwoo Park, Kyoungsik Yu, Seung-Hyun Cho i Joonyoung Kim. "Demonstration of photonics-aided terahertz wireless transmission system with using silicon photonics circuit". Optics Express 28, nr 16 (22.07.2020): 23397. http://dx.doi.org/10.1364/oe.398460.
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Chen, Liming, Xiaoyun Kuang, Fusheng Zhu, Lijia Lai i David Fan. "A Survey on the AI and Spectrum Management for Cache-Enabled Internet of Things in Smart Cities". Wireless Communications and Mobile Computing 2021 (15.07.2021): 1–14. http://dx.doi.org/10.1155/2021/4477596.
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In this paper, we provide a comprehensive survey for the artificial intelligence and spectrum management, which are used for cache-enabled Internet of Things (IoT) in smart cities. In smart cities, there emerge a lot of new applications such as data collection and communication, environment monitoring, and real-time processing, which cannot be supported by the conventional wireless transmission techniques. Hence, some new wireless transmission techniques should be developed to support the emerging applications in smart cities. In this survey, we focus on the artificial intelligence, spectrum management, and caching techniques, where the interference arises due to the limited spectrum resources. In particular, we first review the current research status of these new techniques and, then, give some challenges on the system design. We further provide several feasible solutions on these challenges, in order to implement the IoT networks in smart cities. Finally, we conclude the work in the part of conclusions and give some discussions on the future works.
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Zheng, Yani, Gaurav Dhiman, Ashutosh Sharma, Amit Sharma i Mohd Asif Shah. "An IoT-Based Water Level Detection System Enabling Fuzzy Logic Control and Optical Fiber Sensor". Security and Communication Networks 2021 (27.08.2021): 1–11. http://dx.doi.org/10.1155/2021/4229013.
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The usage of wireless sensors has become widespread for the collection of data for various Internet of Things (IoT) products. Specific wireless sensors use optical fiber technology as transmission media and lightwave signals as carriers, showing the advantages of antielectromagnetic interference, high sensitivity, and strong reliability. Hence, their application in IoT systems becomes a research hotspot. In this article, multiple optical fiber sensors are constructed as an IoT detection system, and a Transmission Control Protocol (TCP)/Internet Protocol (IP) communication stack is used for the sensor module. Furthermore, design of gateway module, data server, and monitoring module is established in order to run the data server in the Windows system and communicate across the network segments. Furthermore, the optical fiber sensor is connected to the development board with WiFi, meanwhile considering the optical fiber wireless network’s congestion problem. The fuzzy logic concept is introduced from the perspective of cache occupancy, and a fiber sensor’s network congestion control algorithm is proposed. In the experiment, the IoT detection system with multiple optical fiber sensors is used for water level detection, and the sensor’s real-time data detected by the User Interface (UI) are consistent with the feedback results. The proposed method is also compared with the SenTCP algorithm and the CODA algorithm, and it was observed that the proposed network congestion control algorithm based on the fuzzy logic can improve network throughput and reduce the network data packet loss.
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Gu, Jinyuan, Yancheng Ji, Wei Duan i Guoan Zhang. "Node Value and Content Popularity-Based Caching Strategy for Massive VANETs". Wireless Communications and Mobile Computing 2021 (5.04.2021): 1–10. http://dx.doi.org/10.1155/2021/5585896.
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The high-speed dynamic environment and massive information transmitted via wireless communications in the vehicular ad hoc networks (VANETs) pose a great challenge to privacy and security. To overcome this issue, use of the content-centric networking (CCN) provides a potential and practical solution. In-network caching is a main feature for future smart cities, in which the content is mainly placed in network nodes. Therefore, how to effectively select the cache locality and cache content is essential to improve the overall network performance, which is an inevitable trend. With these observations, this article proposes a caching strategy based on the node value and content popularity (NVCP) for the massive VANET scenario. In the proposed NVCP scheme, different from the traditional caching strategies, we evaluate the node value from three aspects: the connectivity, intermediary, and eigenvector centralities, synthetically, since the content with different types of popularity is placed in nodes with different values, resulting in the redundancy deterioration and diversity improvement for the content. The proposed caching strategy is evaluated by the stochastic network topology with multifactors, which provides different impacts on the system performance. Simulation results show that the NVCP outperforms the traditional cache strategies for 6G-CCN in terms of the cache hit ratio, average hop count, and transmission latency. Moreover, placing the content in the neighbor nodes is also introduced to further improve the utilization of the cache space and achieve better cache performance.
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Lakshmi, Dr M. Vijaya. "Deep Learning Aided 5G Channel Estimation". International Journal for Research in Applied Science and Engineering Technology 11, nr 6 (30.06.2023): 3821–26. http://dx.doi.org/10.22214/ijraset.2023.54202.
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Abstract: Wireless communications involves the transfer of voiceand data without a cable or wires. It uses orthogonal frequencydivision multiplexing, also known as a multicarrier transmission technique. In multiple input multiple output (MIMO) wireless communication (4G and 5G technologies), channel estimation is crucial. Multiple antennas are used at both the transmit and receive sides ofa MIMO system to increase spectral efficiency and reliability. In 5G channel estimation is performed to improve the accuracy of the received signal. Least-squares estimation is a cheap method with relatively large channel estimationerrors, but it is supported in this work by using a new channel estimation method that leverages deep learning. LS (least squares) and MMSE (minimum mean squared error) are two popular traditional approaches to channel estimation, but deep learning provides much more accurate results than previous channel estimation methods.
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Adanvo, Vignon Fidele, Samuel Mafra, Samuel Montejo-Sánchez, Evelio M. García Fernández i Richard Demo Souza. "Buffer-Aided Relaying Strategies for Two-Way Wireless Networks". Sustainability 14, nr 21 (25.10.2022): 13829. http://dx.doi.org/10.3390/su142113829.
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The energy and time efficiency of wireless sensor networks (WSNs) is frequently affected by the low reliability of their links. To mitigate the outage probability, cooperation topologies are used. However, these topologies have particular challenges since the relay consumes energy in assisting a foreign communication, and the successful transmission in each direction is conditioned to the availability of the two segments involved in the communication. To overcome the temporary unavailability of a link, the use of buffers in the relay has been proposed, but energy and time efficiency remain a challenge for basic configurations. We propose two-way buffer-aided relaying strategies that exploit the presence of buffers in the different nodes that participate in the communication, as well as the efficient use of buffer capacity. The proposed strategies make the decision to forward the messages in one of the communication directions or broadcast coded messages based on buffer and channel state information. Firstly, we evaluate the impact of considering the use of buffers in the transmitter nodes. Then, we propose and evaluate the impact of the full and joint use of the entire buffer capacity to assist communication in both directions. Finally, we evaluate the performance of a system that exploits both the use of full and joint buffering and the presence of buffering in the transmitter. The results show that better performance, in terms of outage probability, is obtained by the third strategy; since it allows the buffer capacity to be exploited to a greater extent in the most urgent direction at each moment, as well as to select the start of each transmission to a viable communication opportunity. This represents a notable benefit in terms of energy and time efficiency for WSNs since unnecessary transmission of information is avoided, the number of idle slots decreases, and the amount of information per unit of time and energy increases.
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Drampalou, Stamatia F., Nikolaos I. Miridakis, Helen C. Leligou i Panagiotis A. Karkazis. "A Survey on Optimal Channel Estimation Methods for RIS-Aided Communication Systems". Signals 4, nr 1 (9.03.2023): 208–34. http://dx.doi.org/10.3390/signals4010012.
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Next-generation wireless communications aim to utilize mmWave/subTHz bands. In this regime, signal propagation is vulnerable to interferences and path losses. To overcome this issue, a novel technology has been introduced, which is called reconfigurable intelligent surface (RIS). RISs control digitally the reflecting signals using many passive reflector arrays and implement a smart and modifiable radio environment for wireless communications. Nonetheless, channel estimation is the main problem of RIS-assisted systems because of their direct dependence on the system architecture design, the transmission channel configuration and methods used to compute channel state information (CSI) on a base station (BS) and RIS. In this paper, a concise survey on the up-to-date RIS-assisted wireless communications is provided and includes the massive multiple input-multiple output (mMIMO), multiple input-single output (MISO) and cell-free systems with an emphasis on effective algorithms computing CSI. In addition, we will present the effectiveness of the algorithms computing CSI for different communication systems and their techniques, and we will represent the most important ones.
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Moon, Sang-Rok, Seungjun Han, Sanghwa Yoo, Heuk Park, Won-Kyoung Lee, Joon Ki Lee, Jongwoo Park, Kyoungsik Yu, Seung-Hyun Cho i Joonyoung Kim. "Demonstration of photonics-aided terahertz wireless transmission system with using silicon photonics circuit: erratum". Optics Express 28, nr 17 (7.08.2020): 24918. http://dx.doi.org/10.1364/oe.404209.
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Islam, Shammi Farhana, Shaikh Enayet Ullah i Md Mahbubar Rahman. "Uncoded Multiview Video Signal Transmission in Pre-ZF Equalization Aided MIMO Wireless Communication System". International Journal of Future Generation Communication and Networking 8, nr 6 (31.12.2015): 13–22. http://dx.doi.org/10.14257/ijfgcn.2015.8.6.02.
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Le, Anh-Tu, Dinh-Thuan Do i Munyaradzi Munochiveyi. "Outage performance of downlink NOMA-aided small cell network with wireless power transfer". Bulletin of Electrical Engineering and Informatics 10, nr 5 (1.10.2021): 2686–95. http://dx.doi.org/10.11591/eei.v10i5.3015.
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This article considers the outage performance of the downlink transmission for a small cell network in a heterogeneous network. Due to mobility and distribution of users, it is necessary to study massive connections and high energy efficiency for such kind of systems. To be an enabler of energy harvesting, a power beacon is helpful to support the base station to send signals to distant users, and wireless power transfer (WPT) is exploited to guarantee the data packets transmission from the power beacon to the base station. To provide massive connections, we propose a novel non-orthogonal multiple access (NOMA) technique combined with WPT to enhance outage performance and latency reduction. Furthermore, we derive outage probability (OP) to characterize the system performance. Simulation results are verified to match well between theoretical and analytical methods, and main parameters are determined to understand how they affect the proposed scheme.
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Nguyen, Nhan Duc, Chi-Bao Le i Munyaradzi Munochiveyi. "Uplink Multiple Access for Reconfigurable Intelligent Surface-Aided Wireless Systems". Wireless Communications and Mobile Computing 2022 (21.07.2022): 1–14. http://dx.doi.org/10.1155/2022/1932708.
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The integration of reconfigurable intelligent surface- (RIS-) aided wireless communication and multiple access is an attractive and promising scheme for next-generation wireless networks. In this research work, separate uplink RIS-aided nonorthogonal multiple access (NOMA) and uplink relay-assisted NOMA schemes are studied, where the RIS and relay devices are deployed to enhance the coverage of an obstructed single-antenna far user by assisting it to communicate with a single-antenna base station. In each scenario, both perfect successive interference cancellation (pSIC) and imperfect successive interference cancellation (ipSIC) operations are considered in the proposed multiple access network. To characterize the system performance, the associated residual interference caused by ipSIC and relay loop self-interference is characterized using the Rayleigh fading model; subsequently, new channel statistics are derived based on the Gauss-Laguerre polynomial. Consequently, the closed-form approximate outage probability expressions are derived for each scenario in the high signal-to-noise ratio (SNR) regime. To gain further insight, the system throughput in the delay-limited transmission is also obtained for each scenario. The formulated expressions are validated via Monte-Carlo simulations. Finally, the obtained simulation results demonstrate and validate the superiority of the RIS system over the relay device under several system parameters of interest despite the limitation of ipSIC.
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Riku Ohmiya, Tomoki Murakami, Masaaki Nishino, Yoghitha Ramamoorthi, Masashi Iwabuchi, Tomoaki Ogawa i Yasushi Takatori. "Massive distributed IRS aided wireless communication with ON/OFF selection". ITU Journal on Future and Evolving Technologies 2, nr 6 (23.09.2021): 83–92. http://dx.doi.org/10.52953/gscs6789.
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The mobile communication system beyond fifth-generation (beyond 5G) is required to maintain higher transmission capacity and reliability than existing 5G systems. To meet these requirements, one promising solution is to incorporate an Intelligent Reflecting Surface (IRS). The IRS involves reconfiguring the wireless propagation environment and exploiting the radio resources, not only in the conventional frequency and time domains but also in the spatial domain by controlling the reflection amplitude and phase of the incident electromagnetic signal. However, increased deployment of IRSs brings about interference and greater complexity. Therefore, in this paper, we propose an ON/OFF IRS selection method on massive IRS aided wireless communications that can simultaneously achieve interference suppression and capacity improvement. In addition, the proposed method reduces operational complexity using a simple 1-bit control. The results of computer simulation and experiment show that the proposed method can improve the desired channel capacity beyond directly Single-Input Single-Output (SISO) communication without IRS while maintaining the interference level of an interfered receiver below a certain threshold.
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Chen, Yun, Guoping Zhang, Hongbo Xu, Wenxing Luo, Yinshuan Ren i Jianqiang Zhang. "Reconfigurable Intelligent Surface-Aided AirComp for Large-Scale IoT Networks". Journal of Sensors 2023 (24.02.2023): 1–10. http://dx.doi.org/10.1155/2023/6629426.
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Traditional wireless data aggregation (WDA) technology based on the principle of separated communication and computation is difficult to achieve large-scale access under the limited spectrum resources, especially in scenarios with strict constraints on time latency. As an outstanding fast WDA technology, over-the-air computation (AirComp) can reduce transmit time while improving spectrum efficiency. Most edge devices in wireless networks are battery-powered. Therefore, optimizing the transmit power of devices could prolong the life cycle of nodes and save the system power consumption. In this research, we aim to minimize the device transmit power subject to aggregation error constraint. Additionally, to improve the harsh wireless transmission environment, we use reconfigurable intelligent surface (RIS) to assist AirComp. To solve the presented nonconvex problem, we present a two-step solution method. Specifically, we introduce matrix lifting technology to transform the original problems into semidefinite programming problems (SDP) in the first step and then propose an alternate difference-of-convex (DC) framework to solve the SDP subproblems. The numerical results show that RIS-assisted communication can greatly save system power and reduce aggregation error. And the proposed alternate DC method is superior to the alternate semidefinite relaxation (SDR) method.
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Ye, Qing, Faxiang Zhao i Weiyang Xu. "NOMA-Based Integrated Satellite-Terrestrial Networks with Wireless Caching". Wireless Communications and Mobile Computing 2022 (13.09.2022): 1–13. http://dx.doi.org/10.1155/2022/6788449.
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To decrease the transmission delay and alleviate communication congestion, caching has been applied in the integrated satellite-terrestrial networks (ISTNs). In traditional caching schemes, the cache-enabled relays update files during off-peak hours and push them during on-peak hours. However, for the enormous number of end devices in ISTNs, the long-time waiting for off/on-peak hours would decrease the quality of service. To address this issue, this paper proposes a two-tier nonorthogonal multiple access- (NOMA-) based ISTN with wireless caching. Specifically, data transmission of this model consists of two phases. For the first phase, named the file-push-and-placement (FPAP), the satellite employs the NOMA protocol to send information to both the relay and first-tier user. While for the second phase, which is called the file-push-and-delivery (FPAD), second-tier users are served by the relay employing NOMA. Performance analysis of the proposed configuration is carried out, focusing on the exact and asymptotic outage probability (OP), diversity order, and hit probability. Moreover, the influence of key factors on the system performance is also investigated. Compared with the traditional configuration, it is shown analytically and numerically that the proposed scheme achieves lower OP and higher diversity order.
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Li, Xinying, Jianjun Yu, Kaihui Wang, Wen Zhou i Jiao Zhang. "Photonics-aided 2 × 2 MIMO wireless terahertz-wave signal transmission system with optical polarization multiplexing". Optics Express 25, nr 26 (21.12.2017): 33236. http://dx.doi.org/10.1364/oe.25.033236.
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Shi, Baihua, Yang Wang, Danqi Li, Wenlong Cai, Jinyong Lin, Shuo Zhang, Weiping Shi, Shihao Yan i Feng Shu. "STAR-RIS-UAV-Aided Coordinated Multipoint Cellular System for Multi-User Networks". Drones 7, nr 6 (17.06.2023): 403. http://dx.doi.org/10.3390/drones7060403.
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Different from conventional reconfigurable intelligent surfaces (RIS), simultaneous transmitting and reflecting RIS (STAR-RIS) can reflect and transmit signals to the receiver. In this paper, to serve more ground users and increase deployment flexibility, we investigate an unmanned aerial vehicle (UAV) equipped with STAR-RIS (STAR-RIS-UAV)-aided wireless communications for multi-user networks. Energy splitting (ES) and mode switching (MS) protocols are considered to control the reflection and transmission coefficients of STAR-RIS elements. To maximize the sum rate of the STAR-RIS-UAV-aided coordinated multipoint (CoMP) cellular system for multi-user networks, the corresponding beamforming vectors as well as transmitted and reflected coefficient matrices are optimized. Specifically, instead of adopting the alternating optimization, we design an iteration method to optimize all variables for both the ES and MS protocols at the same time. Simulation results reveal that the STAR-RIS-UAV-aided CoMP system has a much higher sum rate than systems with conventional RIS or without RIS. Furthermore, the proposed structure is more flexible than fixed STAR-RIS and could greatly promote the sum rate.
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Shi, Fang, Lisheng Fan, Xin Liu, Zhenyu Na i Yanchen Liu. "Probabilistic Caching Placement in the Presence of Multiple Eavesdroppers". Wireless Communications and Mobile Computing 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/2104162.
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The wireless caching has attracted a lot of attention in recent years, since it can reduce the backhaul cost significantly and improve the user-perceived experience. The existing works on the wireless caching and transmission mainly focus on the communication scenarios without eavesdroppers. When the eavesdroppers appear, it is of vital importance to investigate the physical-layer security for the wireless caching aided networks. In this paper, a caching network is studied in the presence of multiple eavesdroppers, which can overhear the secure information transmission. We model the locations of eavesdroppers by a homogeneous Poisson Point Process (PPP), and the eavesdroppers jointly receive and decode contents through the maximum ratio combining (MRC) reception which yields the worst case of wiretap. Moreover, the main performance metric is measured by the average probability of successful transmission, which is the probability of finding and successfully transmitting all the requested files within a radius R. We study the system secure transmission performance by deriving a single integral result, which is significantly affected by the probability of caching each file. Therefore, we extend to build the optimization problem of the probability of caching each file, in order to optimize the system secure transmission performance. This optimization problem is nonconvex, and we turn to use the genetic algorithm (GA) to solve the problem. Finally, simulation and numerical results are provided to validate the proposed studies.
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Van, Hoang Thien, Quyet-Nguyen Van, Danh Hong Le, Hoang-Phuong Van, Jakub Jalowiczor, Hoang-Sy Nguyen i Miroslav Voznak. "Opportunistic DF-AF Selection Relaying in Hybrid Wireless and Power Line Communication for Indoor IoT Networks". Sensors 21, nr 16 (13.08.2021): 5469. http://dx.doi.org/10.3390/s21165469.
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This manuscript investigates the system performance of hybrid wireless and power line communication networks for indoor Internet of Things applications. Differentiating itself from the existing literature, the performance of the direct link and dual-hop energy harvesting relay-aided links is analyzed under the condition of indoor fading modeled by log-normal distribution. Moreover, the manuscript presents the analytical expressions of the successful transmission probability of the deployed opportunistic decode-and-forward and amplify-and-forward relay selection scheme, and validates them with Monte Carlo simulations. Moreover, the impact of different system parameters on the successful transmission probability is revealed. For the considered hybrid system, in general, the opportunistic decode-and-forward relaying scheme outperforms the opportunistic amplify-and-forward relaying scheme. As importantly, increasing the source to relay distance and power splitting ratio over certain limits significantly deteriorates the system performance, indicated by the decrease in the successful transmission probability.
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Liu, Jun, Tao Cui, Lin Zhang, Yuwei Zhang, Jing Wang, Chao Li, Kai Chen i in. "Deep Federated Learning Based Convergence Analysis in Relaying-Aided MEC-IoT Networks". Journal of Engineering 2022 (28.09.2022): 1–6. http://dx.doi.org/10.1155/2022/8425975.
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Recently, deep federated learning has attracted much attention from researchers in the fields of wireless communications, where the relaying technique has been shown as a powerful technology to assist the wireless signals and enhance the transmission quality, which is very important to the development of mobile edge computing (MEC) based Internet of Things (IoT) networks. In a relaying-aided MEC-IoT system, it is of vital importance to deeply investigate the system signal-to-noise ratio (SNR) at the receiver side, as it mainly determines the system performance metrics, such as capacity (or achievable data rate), outage probability, and bit-error-rate (BER). To this end, we first investigate the instantaneous convergence error, by deeply studying the relationship between the instantaneous two-hop relaying channels. We then investigate the statistical convergence error, by performing the statistical expectation with respect to the two-hop relaying channels. We finally present some results to show that the analysis of the convergence error is effective. The work in this paper can provide some theoretical foundation for deep federated learning and computing networks.
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Liang, Yanjun, Hongxi Yin, Lianyou Jing, Xiuyang Ji i Jianying Wang. "Performance Analysis of Relay-Aided NOMA Optical Wireless Communication System in Underwater Turbulence Environment". Remote Sensing 14, nr 16 (11.08.2022): 3894. http://dx.doi.org/10.3390/rs14163894.
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Non-orthogonal multiple access (NOMA) is a promising technology to improve spectrum utilization effectively for underwater optical wireless communications (UOWC). To exploit the benefits of NOMA in a turbulent environment, cooperative transmission has been introduced in the NOMA–UOWC network. The existing studies on NOMA suggest that relay selection and power optimization are the main factors affecting system performance. In this paper, a general NOMA node pairing method and two power optimization schemes for NOMA–UOWC are proposed, and both schemes are proven to be strictly quasi-convex. The two optimization schemes are solved by the BFGS algorithm and the particle swarm algorithm, respectively. The effectiveness of the proposed schemes are evaluated by our simulations, and the main factors affecting the relay-aided NOMA performance are derived.
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Christy, S., i Gladence L. Mary. "Two-level data packet security mechanism – secure location-aided routing (SLAR)". i-manager's Journal on Mobile Applications and Technologies 9, nr 2 (2022): 22. http://dx.doi.org/10.26634/jmt.9.2.19316.
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Secure data transmission is one of the most difficult challenges of Mobile Ad hoc Networks (MANET), it is a group of wireless mobile nodes that creates a temporary network without the help of a centralized system, infrastructure, or access point. Location-Aided Routing (LAR) protocols limit the ad hoc network's search for a new route to a limited "request zone." For safe message transmission in the current Location Aided Routing protocol, the Secure Location Aided Routing algorithm (SLAR) is proposed in this paper. The LAR is a geographic routing protocol that establishes the route discovery region between the source and distance before forwarding the route request packets. SLAR is an extension of LAR where the performance of LAR is compared in the presence and absence of malicious nodes, and the security of LAR is improved by putting cryptographic features in it. SLAR has significantly improved throughput, end-to-end delay, and packet delivery ratio compared to LAR.
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Liu, X., X. Wang, K. Yu, X. Yang, W. Ma, G. Li i X. Zhao. "Secure Data Aggregation Aided by Privacy Preserving in Internet of Things". Wireless Communications and Mobile Computing 2022 (17.03.2022): 1–14. http://dx.doi.org/10.1155/2022/4858722.
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With the rapid development of Internet of Things (IoT), more and more wireless smart devices are widely deployed in its typical applications. These devices acquire numerous data, and their security transmission is a challenge issue due to the openness and broadcast nature of wireless network. Security data aggregation (SDA) plays a significant role in IoT which can not only protect the data privacy but also reduce the network traffic among smart devices. In this paper, a multiple application SDA (MASDA) mechanism is proposed and it can ensure the data confidentiality without losing the integrity of data transmission. Firstly, we discuss an improved homomorphic message authentication code (iHMAC) which can verify the integrity of sensing data and eliminate the injection of false data. Secondly, a multiple application elliptic curve cryptography mechanism (iECC) is described. We introduce multiple types of data simultaneous encryption into an elliptic curve encryption system. This encryption mechanism aggregates the encrypted sensing data and prevents the sensing from being tampered and leaked in relay nodes. Finally, MASDA is a multiple application mechanism and provide both the confidentiality and integrity compared with other SDA schemes. It fuses the sensing data of different applications in a single data packet, and the base station can recover them one-by-one. The security analysis and the simulation experiments verify that MASDA has better performances in terms of the security, the computation cost, the communication overhead, and the data accuracy.
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Chen, Guihong, Xi Liu, Mohammad Shorfuzzaman, Ali Karime, Yonghua Wang i Yuanhang Qi. "MEC-Based Jamming-Aided Anti-Eavesdropping with Deep Reinforcement Learning for WBANs". ACM Transactions on Internet Technology 22, nr 3 (31.08.2022): 1–17. http://dx.doi.org/10.1145/3453186.
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Wireless body area network (WBAN) suffers secure challenges, especially the eavesdropping attack, due to constraint resources. In this article, deep reinforcement learning (DRL) and mobile edge computing (MEC) technology are adopted to formulate a DRL-MEC-based jamming-aided anti-eavesdropping (DMEC-JAE) scheme to resist the eavesdropping attack without considering the channel state information. In this scheme, a MEC sensor is chosen to send artificial jamming signals to improve the secrecy rate of the system. Power control technique is utilized to optimize the transmission power of both the source sensor and the MEC sensor to save energy. The remaining energy of the MEC sensor is concerned to ensure routine data transmission and jamming signal transmission. Additionally, the DMEC-JAE scheme integrates with transfer learning for a higher learning rate. The performance bounds of the scheme concerning the secrecy rate, energy consumption, and the utility are evaluated. Simulation results show that the DMEC-JAE scheme can approach the performance bounds with high learning speed, which outperforms the benchmark schemes.
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Liu, Yue Liang. "Research on Low Speed Serial Links Transmission Optimization Technology". Applied Mechanics and Materials 511-512 (luty 2014): 954–57. http://dx.doi.org/10.4028/www.scientific.net/amm.511-512.954.
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In order to overcome the low speed serial links of the bandwidth low, easy to produce decline, low rate of transmission characteristics, This paper design a transmission optimization system, In the system, this paper proposes a forward error correction and data compression transmission optimization combined method, Transmission optimization technology in recent years has been widely used in the field of network communication. Transmission optimization technology has been shown to improve the utilization rate of bandwidth, improve transmission efficiency. In this paper, the transmission optimization of the forward error correction technology has carried on the simulation test, And the analysis of experimental data were compared before and after the optimization, The experimental results show that the proposed transmission optimization method for low speed serial links the data transmission efficiency has been obviously increased . Transmission Optimization Technology Transmission optimization techniques include forward error correction, data compression, and adaptive protocol of three parts, combined guarantee bad message transmission efficiency in transmission environment. This paper mainly studies the transmission on the wireless communication channel environment serial links optimization techniques. Bandwidth Compression Technology. Bandwidth compression is transmitted through compression technology after traditional smaller packets, such as real time transmission of packets is more than the number of packets before compression, so as to realize the goal of improving transmission speed. Bandwidth compression technology is not really to data compression, because the network of packet size and length size has strict rules, if the size of the data has changed, and is also change his nature. So the true meaning of bandwidth compression is part of the data in other ways to replace, including cache corresponding not change information data or with short data instead of long, Then after receiving inverse substitution process, complete the purpose of saving bandwidth. The most commonly used three kinds of compression algorithm: Huffinan coding, dictionary coding and arithmetic coding [.
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Farhana Islam, Shammi. "Assessment of Secured Voice Frequency Signal Transmission in Dual Polarized DWT Aided MIMO SC-FDMA Wireless Communication System". International Journal of Wireless Communications and Mobile Computing 3, nr 5 (2015): 51. http://dx.doi.org/10.11648/j.wcmc.20150305.12.
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AlJubayrin, Saad, Fahd N. Al-Wesabi, Hadeel Alsolai, Mesfer Al Duhayyim, Mohamed K. Nour, Wali Ullah Khan, Asad Mahmood, Khaled Rabie i Thokozani Shongwe. "Energy Efficient Transmission Design for NOMA Backscatter-Aided UAV Networks with Imperfect CSI". Drones 6, nr 8 (28.07.2022): 190. http://dx.doi.org/10.3390/drones6080190.
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The recent combination of ambient backscatter communication (ABC) with non-orthogonal multiple access (NOMA) has shown great potential for connecting large-scale Internet of Things (IoT) in future unmanned aerial vehicle (UAV) networks. The basic idea of ABC is to provide battery-free transmission by harvesting the energy of existing RF signals of WiFi, TV towers, and cellular base stations/UAV. ABC uses smart sensor tags to modulate and reflect data among wireless devices. On the other side, NOMA makes possible the communication of more than one IoT on the same frequency. In this work, we provide an energy efficient transmission design ABC-aided UAV network using NOMA. This work aims to optimize the power consumption of a UAV system while ensuring the minimum data rate of IoT. Specifically, the transmit power of UAVs and the reflection coefficient of the ABC system are simultaneously optimized under the assumption of imperfect channel state information (CSI). Due to co-channel interference among UAVs, imperfect CSI, and NOMA interference, the joint optimization problem is formulated as non-convex, which involves high complexity and makes it hard to obtain the optimal solution. Thus, it is first transformed and then solved by a sub-gradient method with low complexity. In addition, a conventional NOMA UAV framework is also studied for comparison without involving ABC. Numerical results demonstrate the benefits of using ABC in a NOMA UAV network compared to the conventional UAV framework.
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Fu, Ya Ru, i Qi Zhu. "A Novel Proportional Fairness Scheduling for Subcarrier Allocation in OFDM Based Relaying Systems". Advanced Materials Research 765-767 (wrzesień 2013): 436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.436.
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Different data rate services are expected to support for heterogeneous users in OFDM based relaying networks. And fairness of users is an important factor that cannot be neglected in the process of resource allocation, particularly for users at the cell edge. The traditional proportional fairness (PF) scheduling algorithm provides a trade-off between average throughout and fairness in wireless communication networks. This paper investigates subcarrier allocation problem of Orthogonal Frequency Division Multiplexing (OFDM) aided relaying systems with PF constraint and proposes an efficient PF scheduling priority by using the users channel condition of past scheduling time and current scheduling time more comprehensively and uniformly which can both maximize the system transmission rate and enhance the system fairness no less than traditional ones. The simulation results show the validity.
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Kim, Yeong-Rok, Jun-Hyun Park, Jae-Mo Kang, Dong-Woo Lim i Kyu-Min Kang. "Deep Learning-Aided Downlink Beamforming Design and Uplink Power Allocation for UAV Wireless Communications with LoRa". Applied Sciences 12, nr 10 (10.05.2022): 4826. http://dx.doi.org/10.3390/app12104826.
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In this paper, we consider an unmanned aerial vehicle (UAV) wireless communication system where a base station (BS) equipped multi antennas communicates with multiple UAVs, each equipped with a single antenna, using the LoRa (Long Range) modulation. The traditional approaches for downlink beamforming design or uplink power allocation rely on the convex optimization technique, which is prohibitive in practice or even infeasible for the UAVs with limited computing capabilities, because the corresponding convex optimization problems (such as second-order cone programming (SOCP) and linear programming (LP)) requiring a non-negligible complexity need to be re-solved many times while the UAVs move. To address this issue, we propose novel schemes for beamforming design for downlink transmission from the BS to the UAVs and power allocation for uplink transmission from the UAVs to the BS, respectively, based on deep learning. Numerical results demonstrate a constructed deep neural network (DNN) can predict the optimal value of the downlink beamforming or the uplink power allocation with low complexity and high accuracy.
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Yang, Ding Cheng, Lin Xiao, Tian Kui Zhang i Wei Wang. "Study on Quantize-and-Forward Relaying with Interference Alignment for Relay Networks". Advanced Materials Research 846-847 (listopad 2013): 629–34. http://dx.doi.org/10.4028/www.scientific.net/amr.846-847.629.
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Relaying is one of the key technological enhancements for the data rate and coverage requirements of wireless networks. The interference alignment (IA) is a promising method for co-channel interference in wireless networks. In this paper, we investigate the quantize-and-forward (QF) relaying strategy with IA in the relay networks. The multi-user transmission aided by the relay is a common case in the wireless networks and can be modeled as multi-user relaying interference channels. We design a method for QF relaying strategy at the relay and propose precoding of IA to process the interference at each user. Then we derive the sum rate of the system and simulate it with the varying transmitted power and the distance between the user and the relay. The simulation results show that, the sum rate of designed QF relaying with IA has a better performance than those of the existing methods or processed algorithms.
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Fan, Dahua, Jianghong Ou, Bowen Lu, Shiwei Lai, Yajuan Tang, Tao Cui i Chengyuan Fan. "Intelligent Reflecting Surface Aided Cloud Access Networks with Federated Learning". ICST Transactions on Mobile Communications and Applications 7, nr 4 (17.01.2023): e1. http://dx.doi.org/10.4108/eetmca.v7i4.2903.
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Compared with traditional cellular network architecture, cloud access network has some significant advantages in spectrum utilization, energy consumption and network construction cost. However, a high-quality forward link is required between the baseband processing unit pool and remote radio head (RRH) in the cloud access network, which results in limited RRH deployment and affects user access link transmission and coverage. To solve this issue, this paper introduces the intelligent reflector technology into the cloud access network as a solution with low energy consumption, low cost and easy deployment to deal with the existing bottlenecks. Firstly, an efficient channel information acquisition strategy based on federated learning is designed for the smart reflector to enhance the user access link, so as to achieve a compromise between the channel estimation accuracy and cost. On this basis, a robust beamforming design and optimization method of the compression mechanism of the forward link are proposed for the smart reflector to enhance the user access link and the wireless forward link, so as to improve the system transmission performance. Finally, we explore the joint resource allocation method of intelligent reflector assisted cloud access network, and improve the system energy efficiency through the collaborative configuration of intelligent reflector and cloud access network communication resources. The research of this paper will provide an important theoretical basis for the application of intelligent reflectors in cloud access networks, especially for the federated learning.
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Hui, Hancheng. "Intelligent Resource Allocation Method for Wireless Communication Networks Based on Deep Learning Techniques". Journal of Sensors 2021 (5.10.2021): 1–12. http://dx.doi.org/10.1155/2021/3965087.
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In this paper, a deep learning approach is used to conduct an in-depth study and analysis of intelligent resource allocation in wireless communication networks. Firstly, the concepts related to CSCN architecture are discussed and the throughput of small base stations (SBS) in CSCN architecture is analyzed; then, the long short-term memory network (LSTM) model is used to predict the mobile location of users, and the transmission conditions of users are scored based on two conditions, namely, the mobile location of users and whether the small base stations to which users are connected have their desired cache states, and the small base stations select the transmission. The small base station selects several users with optimal transmission conditions based on the scores; then, the concept of game theory is introduced to model the problem of maximizing network throughput as a multi-intelligent noncooperative game problem; finally, a deep augmented learning-based wireless resource allocation algorithm is proposed to enable the small base station to learn autonomously and select channel resources based on the network environment to maximize the network throughput. Simulation results show that the algorithm proposed in this paper leads to a significant improvement in network throughput compared to the traditional random-access algorithm and the algorithm proposed in the literature. In this paper, we apply it to the fine-grained resource control problem of user traffic allocation and find that the resource control technique based on the AC framework can obtain a performance very close to the local optimal solution of a matching-based proportional fair user dual connection algorithm with polynomial-level computational complexity. The resource allocation and task unloading decision policy optimization is implemented, and at the end of the training process, each intelligent body independently performs resource allocation and task unloading according to the current system state and policy. Finally, the simulation results show that the algorithm can effectively improve the quality of user experience and reduce latency and energy consumption.
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Hui, Hancheng. "Intelligent Resource Allocation Method for Wireless Communication Networks Based on Deep Learning Techniques". Journal of Sensors 2021 (5.10.2021): 1–12. http://dx.doi.org/10.1155/2021/3965087.
Pełny tekst źródłaStreszczenie:
In this paper, a deep learning approach is used to conduct an in-depth study and analysis of intelligent resource allocation in wireless communication networks. Firstly, the concepts related to CSCN architecture are discussed and the throughput of small base stations (SBS) in CSCN architecture is analyzed; then, the long short-term memory network (LSTM) model is used to predict the mobile location of users, and the transmission conditions of users are scored based on two conditions, namely, the mobile location of users and whether the small base stations to which users are connected have their desired cache states, and the small base stations select the transmission. The small base station selects several users with optimal transmission conditions based on the scores; then, the concept of game theory is introduced to model the problem of maximizing network throughput as a multi-intelligent noncooperative game problem; finally, a deep augmented learning-based wireless resource allocation algorithm is proposed to enable the small base station to learn autonomously and select channel resources based on the network environment to maximize the network throughput. Simulation results show that the algorithm proposed in this paper leads to a significant improvement in network throughput compared to the traditional random-access algorithm and the algorithm proposed in the literature. In this paper, we apply it to the fine-grained resource control problem of user traffic allocation and find that the resource control technique based on the AC framework can obtain a performance very close to the local optimal solution of a matching-based proportional fair user dual connection algorithm with polynomial-level computational complexity. The resource allocation and task unloading decision policy optimization is implemented, and at the end of the training process, each intelligent body independently performs resource allocation and task unloading according to the current system state and policy. Finally, the simulation results show that the algorithm can effectively improve the quality of user experience and reduce latency and energy consumption.
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Jiang, Xiao, Peng Li, Bin Li, Yulong Zou i Ruchuan Wang. "Security-Reliability Tradeoff for Friendly Jammer Aided Multiuser Scheduling in Energy Harvesting Communications". Security and Communication Networks 2021 (3.04.2021): 1–16. http://dx.doi.org/10.1155/2021/5599334.
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In this paper, we investigate the physical-layer security in an energy-harvesting (EH) multiuser network with the help of a friendly jammer (J), where multiple eavesdroppers are considered to tap the information transmission from users (Us) to base station (BS). In this system, a power beacon (PB) transmits radio frequency (RF) signals to Us for charging. In order to enhance the security of wireless transmission, we propose non-energy-aware multiuser scheduling (NEAMUS) scheme and energy-aware multiuser scheduling (EAMUS) scheme. For the purpose of comparison, we introduce conventional round robin multiuser scheduling (CRRMUS) scheme. The closed-form outage probability (OP) and intercept probability (IP) expressions of NEAMUS, EAMUS, and CRRMUS schemes are derived over Rayleigh fading channels. Additionally, we analyze the security-reliability tradeoff (SRT) of NEAMUS, EAMUS, and CRRMUS schemes in terms of OP and IP. Numerical results show that the proposed EAMUS scheme is superior to the CRRMUS scheme and NEAMUS scheme in terms of SRT, demonstrating the advantage of the proposed EAMUS scheme in improving the physical-layer security and reliability. Moreover, SRT performance of NEAMUS and EAMUS schemes can also be improved by increasing the number of users.
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Zhang, Junhao, Jiao Zhang, Qingsong Wang, Jian Chen, Wei Luo, Shitong Xiang, Yuancheng Cai i in. "Experimental Comparison of Carrier Phase Recovery Algorithms for Uniform and Probabilistically Shaped QAM in a 324.1 Gb/S Fiber-mm-Wave Integration System at W-Band". Photonics 10, nr 8 (12.08.2023): 927. http://dx.doi.org/10.3390/photonics10080927.
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We have experimentally implemented a photonics-aided large-capacity fiber-mm-wave wireless communication system employing a simple dual-polarized single-input single-output (SISO) wireless based on polarization multiplexing at the W-band. To compare the performance of different algorithms, 18G-baud, and 35G-baud 16-level quadrature-amplitude-modulation (16QAM), probabilistically shaped 16QAM (PS-16QAM), 64QAM and PS-64QAM signal using different carrier phase recovery (CPR) algorithms are transmitted in the system. Moreover, we compare the Viterbi–Viterbi (VV), improved new algorithm based on VV (NVV), blind phase search (BPS), and two-stage BPS algorithms’ computational complexity to better compare different algorithms. Using the experiment result, we can demonstrate that the BPS algorithm is about half a magnitude better than the NVV algorithm for PS-QAM signals, while the NVV algorithm has the lowest computational complexity. Additionally, we also achieve error-free wireless transmission at a net data rate of 324.1 Gb/s with the bit error ratio (BER) below the forward-error correction (FEC) threshold of 1 × 10−2 assuming soft-decision forward-error correction (SD-FEC) when using the BPS algorithm.
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Panahi, Fereidoun H., Farzad H. Panahi i Tomoaki Ohtsuki. "Spectrum-Aware Energy Efficiency Analysis in K-tier 5G HetNets". Electronics 10, nr 7 (1.04.2021): 839. http://dx.doi.org/10.3390/electronics10070839.
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In future multi-tier cellular networks, cognitive radio (CR) compatible with device-to-device (D2D) communication can be an aid to enhance system spectral efficiency (SE) and energy efficiency (EE). Users in proximity can establish a direct connection with D2D communication and bypass the base stations (BSs), thereby offloading the network infrastructure and providing EE improvement. We use stochastic geometry to model and analyze cognitive D2D communication underlying a multi-tier/multi-channel cellular network where the D2D transmitters are capable of harvesting RF energy from ambient interference resulting from simultaneous cellular downlink transmissions. For further improvement in EE, small cells (SCs) can be put into a power-saving mode by specifying a load-dependent transmission power coefficient (TPC) for SC BSs. In addition, to consider practical D2D communication scenarios, we propose a wireless video sharing framework where cache-enabled users can store and exchange popular video files through D2D communication. We investigate the potential effects of the TPC and the introduced D2D layer on the network EE and SE. We will also observe that the energy-harvesting CR-based D2D communication network design will not only ease the spectrum shortage problem but will also result in a greener network thanks to its reliance on ambient energies.
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Masotti, Diego, Alessandra Costanzo i Vittorio Rizzoli. "Smart Wireless Power Transfer Operated by Time-Modulated Arrays via a Two-Step Procedure". International Journal of Antennas and Propagation 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/673536.
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The paper introduces a novel method for agile and precise wireless power transmission operated by a time-modulated array. The unique, almost real-time reconfiguration capability of these arrays is fully exploited by a two-step procedure: first, a two-element time-modulated subarray is used for localization of tagged sensors to be energized; the entire 16-element TMA then provides the power to the detected tags, by exploiting the fundamental and first-sideband harmonic radiation. An investigation on the best array architecture is carried out, showing the importance of the adopted nonlinear/full-wave computer-aided-design platform. Very promising simulated energy transfer performance of the entire nonlinear radiating system is demonstrated.
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Nusenu, Shaddrack Yaw. "Authentication and Secrecy of Multicast Communication Scenario: Artificial Noise-Aided Costas Sequence Matrix FDA Approach". Security and Communication Networks 2020 (30.06.2020): 1–13. http://dx.doi.org/10.1155/2020/2194840.
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In multicast communication scenario, the desired users are decomposed into M groups to receive private M useful data from the transmitter, while eavesdroppers (Eves) group tries to intercept. Since wireless security system consists of authentication and secure transmission, we propose directional modulation (DM) artificial noise (AN) matrix-aided Costas sequence (CS) matrix frequency diverse array (FDA) in multicast precoding systems in this paper. Specifically, we utilize the CS matrix for desired groups authentication (i.e., group identity), and it is shared via a low-speed forward link in advance. Next, we design AN matrix-aided FDA to offer robust antieavesdropping method based on leakage concept. Furthermore, we devise secrecy metrics, namely, secrecy outage probability (SOP), asymptotic Eve’s detectability error probability, and average useful data leakage rate, based on the scenario where Eve’s instantaneous channel state information (CSI) is unavailable. In addition, we numerically analyze the proposed energy beamforming focusing and evaluate the secrecy energy efficiency. Via simulation results, the proposed scheme gives important insights into how to design and measure secrecy performances in multicast scenarios.
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Ge, Weili, Zhengyu Zhu, Wanming Hao, Yi Wang, Zhongyong Wang, Qiong Wu i Zheng Chu. "AN-Aided Secure Beamforming in Power-Splitting-Enabled SWIPT MIMO Heterogeneous Wireless Sensor Networks". Electronics 8, nr 4 (25.04.2019): 459. http://dx.doi.org/10.3390/electronics8040459.
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In this paper, we investigate the physical layer security in a two-tier heterogeneous wireless sensor network (HWSN) depending on simultaneous wireless information and power transfer (SWIPT) approach for multiuser multiple-input multiple-output wiretap channels with artificial noise (AN) transmission, where a more general system framework of HWSN only includes a macrocell and a femtocell. For the sake of implementing security enhancement and green communications, the joint optimization problem of the secure beamforming vector at the macrocell and femtocell, the AN vector, and the power splitting ratio is modeled to maximize the minimal secrecy capacity of the wiretapped macrocell sensor nodes (M-SNs) while considering the fairness among multiple M-SNs. To reduce the performance loss of the rank relaxation from the SDR technique while solving the non-convex max–min program, we apply successive convex approximation (SCA) technique, first-order Taylor series expansion and sequential parametric convex approximation (SPCA) approach to transform the max–min program to a second order cone programming (SOCP) problem to iterate to a near-optimal solution. In addition, we propose a novel SCA-SPCA-based iterative algorithm while its convergence property is proved. The simulation shows that our SCA-SPCA-based method outperforms the conventional methods.
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Gao, Jianbang, Zhaohui Yuan, Jing Zhou i Bin Qiu. "Artificial-Noise-Aided Energy-Efficient Secure Multibeam Wireless Communication Schemes Based on Frequency Diverse Array". Wireless Communications and Mobile Computing 2020 (24.06.2020): 1–14. http://dx.doi.org/10.1155/2020/4715929.
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In this paper, we research synthesis scheme for secure wireless communication in multibeam directional modulation (MBDM) system, which consists of multiple legitimate users (LUs) receiving their own individual confidential messages, respectively, and multiple eavesdroppers (Eves) intercepting confidential messages. We propose a new type of array antennas, termed frequency diverse arrays (FDA), to enhance security of confidential messages. Leveraging FDA technology and artificial noise (AN) technology, we aim to address the PHY security problem for MBDM by jointly optimizing the frequency offsets, the precoding matrix and the AN projection matrix. In the first stage, with known locations of Eves, precoding matrix is designed to minimize Eve’s receiving power of confidential message (Min-ERP), while satisfying power requirement of LUs. And then artificial-noise projection matrix (ANPM) is calculated to enhance AN impact on Eves without influencing LUs. Furthermore, we research a more practical scenario, where locations of Eves are unknown. Unlike the scenario of the known locations of Eves, precoding matrix is designed to maximize AN transmit power (Max-ATP), while satisfying each LU’s requirement received power of confidential message. In the second stage, we analyze and further optimize secrecy capacity. The problem is solved by optimizing frequency offsets through modified artificial bee colony (M-ABC) algorithm. Numerical results show that the proposed scheme can achieve a secure transmission in MBDM system.
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Khalil, Amaad, Nasru minallah, Muhammad Asfandyar Awan, Hameed Ullah Khan, Atif Sardar Khan i Atiq ur Rehman. "On the Performance of Wireless Video Communication Using Iterative Joint Source Channel Decoding and Transmitter Diversity Gain Technique". Wireless Communications and Mobile Computing 2020 (23.12.2020): 1–16. http://dx.doi.org/10.1155/2020/8873912.
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In this research work, we have presented an iterative joint source channel decoding- (IJSCD-) based wireless video communication system. The anticipated transmission system is using the sphere packing (SP) modulation assisted differential space-time spreading (DSTS) multiple input-multiple output (MIMO) scheme. SP modulation-aided DSTS transmission mechanism results in achieving high diversity gain by keeping the maximum possible Euclidean distance between the modulated symbols. Furthermore, the proposed DSTS scheme results in a low-complexity MIMO scheme, due to nonemployment of any channel estimation mechanism. Various combinations of source bit coding- (SBC-) aided IJSCD error protection scheme has been used, while considering their identical overall bit rate budget. Artificial redundancy is incorporated in the source-coded stream for the proposed SBC scheme. The motive of adding artificial redundancy is to increase the iterative decoding performance. The performance of diverse SBC schemes is investigated for identical overall code rate. SBC schemes are employed with different combinations of inner recursive systematic convolutional (RSC) codes and outer SBC codes. Furthermore, the convergence behaviour of the employed error protection schemes is investigated using extrinsic information transfer (EXIT) charts. The results of experiments show that our proposed R a t e − 2 / 3 SBC-assisted error protection scheme with high redundancy incorporation and convergence capability gives better performance. The proposed R a t e − 2 / 3 SBC gives about 1.5 dB E b / N 0 gain at the PSNR degradation point of 1 dB as compared to R a t e − 6 / 7 SBC-assisted error protection scheme, while sustaining the overall bit rate budget. Furthermore, it is also concluded that the proposed R a t e − 2 / 3 SBC-assisted scheme results in E b / N 0 gain of 24 dB at the PSNR degradation point of 1 dB with reference to R a t e − 1 SBC benchmarker scheme.
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Pierucci, Laura. "Hybrid Direction of Arrival Precoding for Multiple Unmanned Aerial Vehicles Aided Non-Orthogonal Multiple Access in 6G Networks". Applied Sciences 12, nr 2 (16.01.2022): 895. http://dx.doi.org/10.3390/app12020895.
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Unmanned aerial vehicles (UAV) have attracted increasing attention in acting as a relay for effectively improving the coverage and data rate of wireless systems, and according to this vision, they will be integrated in the future sixth generation (6G) cellular network. Non-orthogonal multiple access (NOMA) and mmWave band are planned to support ubiquitous connectivity towards a massive number of users in the 6G and Internet of Things (IOT) contexts. Unfortunately, the wireless terrestrial link between the end-users and the base station (BS) can suffer severe blockage conditions. Instead, UAV relaying can establish a line-of-sight (LoS) connection with high probability due to its flying height. The present paper focuses on a multi-UAV network which supports an uplink (UL) NOMA cellular system. In particular, by operating in the mmWave band, hybrid beamforming architecture is adopted. The MUltiple SIgnal Classification (MUSIC) spectral estimation method is considered at the hybrid beamforming to detect the different direction of arrival (DoA) of each UAV. We newly design the sum-rate maximization problem of the UAV-aided NOMA 6G network specifically for the uplink mmWave transmission. Numerical results point out the better behavior obtained by the use of UAV relays and the MUSIC DoA estimation in the Hybrid mmWave beamforming in terms of achievable sum-rate in comparison to UL NOMA connections without the help of a UAV network.