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Articoli di riviste sul tema "Space Division Multiple Access (SDMA)"

Autore: Grafiati

Pubblicato: 25 gennaio 2025

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1

Hujun Yin e Hui Liu. "Performance of space-division multiple-access (SDMA) with scheduling". IEEE Transactions on Wireless Communications 1, n. 4 (ottobre 2002): 611–18. http://dx.doi.org/10.1109/twc.2002.804188.

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2

Maruta, Kazuki. "Frequency Domain Backoff for Continuous Beamforming Space Division Multiple Access on Massive MIMO Wireless Backhaul Systems". Journal of communications software and systems 16, n. 1 (15 marzo 2020): 1–10. http://dx.doi.org/10.24138/jcomss.v16i1.920.

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This paper newly proposes a frequency domain backoff scheme dedicated to continuous beamforming space division multiple access (CB-SDMA) on massive antenna systems for wireless entrance (MAS-WE). The entrance base station (EBS) has individual base band signal processing units for respective relay stations (RSs) to be accommodated. EBS then continuously applies beamforming weight to transmission/reception signals. CB-SDMA yields virtual point-to-point backhaul link where radio resource control messages and complicated multiuser scheduling are not required. This simplified structure allows RSs to work in a distributed manner. However, one issue remains to be resolved; overloaded multiple access resulting in collision due to its random access nature. The frequency domain backoff mechanism is introduced instead of the time domain one. It can flexibly avoid co-channel interference caused by excessive spatial multiplexing. Computer simulation verifies its superiority in terms of system throughput and packet delay.

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3

Tsoulos, G., J. McGeehan e M. Beach. "Space division multiple access (SDMA) field trials. Part 2: Calibration and linearity issues". IEE Proceedings - Radar, Sonar and Navigation 145, n. 1 (1998): 79. http://dx.doi.org/10.1049/ip-rsn:19981781.

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4

Tsoulos, G., J. McGeehan e M. Beach. "Space division multiple access (SDMA) field trials. Part 1: Tracking and BER performance". IEE Proceedings - Radar, Sonar and Navigation 145, n. 1 (1998): 73. http://dx.doi.org/10.1049/ip-rsn:19981782.

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5

ALANSI, M., I. ELSHAFIEY, A. AL-SANIE, S. ALGHUWAINEM e H. AL-SHARARI. "MC-OFDMA FOR MULTI-USER DETECTION SCHEMES IN POWERLINE COMMUNICATION". Journal of Circuits, Systems and Computers 22, n. 08 (settembre 2013): 1350063. http://dx.doi.org/10.1142/s0218126613500631.

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Support of multiple users in wideband powerline communication (PLC) is essential to enhance the dependence on such emerging systems. This paper presents novel adaptations of the space division multiple access (SDMA) techniques to PLC. Multicarrier data transmission and orthogonal frequency division multiple access (OFDMA) techniques are invoked to mitigate the technical challenges of PLC channel impairments and enhance the spectral efficiency. Performance is enhanced using orthogonal Walsh–Hadamard codes. Linear and nonlinear multi-user detection (MUD) schemes are investigated, including the optimal maximum likelihood (ML) methods and the near-optimal sphere detectors(SDs). Presented results indicate the potential of the proposed scheme to enhance wideband PLC systems.

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Li, Shuang Zhi, Zhe Zhang, Xiao Min Mu e Jian Kang Zhang. "Joint Multiple-Access Channel Effective Order and CIR Estimation Algorithm for Multi-User OFDM/SDMA System". Applied Mechanics and Materials 548-549 (aprile 2014): 1227–30. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.1227.

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In this paper, a novel joint estimation of channel effective order and channel impulse response (CIR) is presented for multiuser orthogonal frequency division multiplexing/space-division multiple-access (OFDM/SDMA) systems. By exploiting Akaike’s Information Criterion (AIC) as the fitness function to search the optimal order, the proposed scheme performs the channel effective order and CIR estimation in a parallel way based on differential evolution (DE) algorithm. Simulation results demonstrate that the proposed scheme is capable of attaining a better mean square error performance than the fixed channel order scheme, and improving the performance of time-domain maximum likelihood (ML) channel estimator.

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7

Ilcev, Stojce Dimov. "Analyses of Space Division Multiple Access (SDMA) Schemes for Global Mobile Satellite Communications (GMSC)". TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation 14, n. 4 (2020): 821–30. http://dx.doi.org/10.12716/1001.14.04.05.

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8

Tsoulos, G. V. "Experimental and theoretical capacity analysis of space-division multiple access (SDMA) with adaptive antennas". IEE Proceedings - Communications 146, n. 5 (1999): 307. http://dx.doi.org/10.1049/ip-com:19990623.

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9

Alansi, Mohammed, Ibrahim Elshafiey, Abdulhameed Al-Sanie e Md Anowar Hossain. "Multi-User Detection for Radar and Communication Multifunction System". Journal of Circuits, Systems and Computers 24, n. 03 (10 febbraio 2015): 1550038. http://dx.doi.org/10.1142/s0218126615500383.

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A multifunctional system that performs synthetic aperture radar (SAR) and communication tasks is presented. The system depends on orthogonal frequency division multiplexing (OFDM) waveform shaping and multiple input multiple output (MIMO) configuration to achieve enhancement in the spectral efficiency of communication operation and provide interference rejection in SAR imaging. The SAR interval idle time is utilized to enhance the communication signal through diversity. Adaptive system features are introduced to achieve multi-user detection and improve the communication reliability, by means of space division multiple access (SDMA) and space–time block coding (STBC). Investigations of linear and nonlinear multi-user detection (MUD) techniques are provided. Moreover, a genetic algorithm-based system is developed to optimize the MUD problem and to provide near-optimal performance even for overloaded scenarios. A gain of more than 4 dB is achieved at bit error rate of 10-2.

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Uthansakul, Peerapong, e Marek E. Bialkowski. "An Adaptive Power and Bit Allocation Algorithm for MIMO OFDM/SDMA System Employing Zero-Forcing Multi-user Detection". African Journal of Information & Communication Technology 2, n. 2 (12 luglio 2006): 63. http://dx.doi.org/10.5130/ajict.v2i2.217.

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The paper describes an adaptive algorithm for power and bit allocations in a multiple user Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) system with Space Division Multiple Access, which operates in a frequency selective fading channel. The zero forcing (ZF) technique is applied to accomplish multi user detection (MUD). A Lagrange multiplier method is applied to obtain a one-step solution for optimal power and bit allocations in this system. The resulting algorithm is advantageous over an alternative Greedy algorithm, because it does not require a time-consuming iterative procedure for its implementation. The algorithm assigns bits and power for all users according to the channel state information (CSI), which is assumed to be fully or partially available to the transmitter. The simulation results show the proposed algorithm operates successfully in multiple user access scenarios.

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11

Li, Yanlong, Syed Agha Hassnain Mohsan, Xiao Chen, Riffat Tehseen, Shuaixing Li e Jianzhao Wang. "Research on Power Allocation in Multiple-Beam Space Division Access Based on NOMA for Underwater Optical Communication". Sensors 23, n. 3 (3 febbraio 2023): 1746. http://dx.doi.org/10.3390/s23031746.

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To meet the transmission requirements of different users in a multiple-beam access system for underwater optical communication (UWOC), this paper proposes a novel multiple-beam space division multiple access (MB-SDMA) system by utilizing a directional radiation communication beam of the hemispherical LED arrays. The system’s access users in the different beams are divided into two categories: the users with a single beam and the users with multiple beams. We also propose a power allocation algorithm that guarantees the quality of service (QoS) for single beam and multiple beam access, especially the QoS for edge users, and fairness for all users. An optimization model of power distribution under the constraints of specific light-emitting diode (LED) emission power is established for two scenarios, which ensure the user QoS for edge users and the max–min fairness for fair users. Using the Karush–Kuhn–Tucker (KKT) condition and the bisection method, we obtain the optimal power allocation expression for the two types of users in the optimization model. Through simulation, we verify that the proposed user classification and power allocation method can ensure the fairness of fair users on the premise of ensuring the QoS of edge users. At the same time, we know that the number of users will affect the improvement of the minimum rate, and the throughput of the non-orthogonal multiple access (NOMA) system is greatly improved compared with the traditional orthogonal multiple access (OMA) systems.

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Maruta, Kazuki, Atsushi Ohta, Yushi Shirato, Satoshi Kurosaki, Takuto Arai, Tatsuhiko Iwakuni e Masataka Iizuka. "CB-SDMA: Continuous beamforming space division multiple access on massive antenna systems for wireless entrance (MAS-WE)". IEICE Communications Express 6, n. 1 (2017): 59–64. http://dx.doi.org/10.1587/comex.2016xbl0154.

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Maeng, Juhyun, Mwamba Kasongo Dahouda e Inwhee Joe. "Optimal Power Allocation with Sectored Cells for Sum-Throughput Maximization in Wireless-Powered Communication Networks Based on Hybrid SDMA/NOMA". Electronics 11, n. 6 (8 marzo 2022): 844. http://dx.doi.org/10.3390/electronics11060844.

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Wireless-powered communication networks (WPCNs) consist of wireless devices (WDs) that transmit information to the hybrid access point (HAP). In this situation, there is interference among WDs that is considered to be noise and causes information loss because of adjacent signals. Moreover, power is limited and can be lost if transmission distance is long. This paper studies sum-throughput maximization with sectored cells for WPCN. We designed a downlink (DL) energy beamforming by sector based on the hybrid space division multiple access (SDMA) and nonorthogonal multiple access (NOMA) approach to maximize the sum throughput. First, a cell is divided into several sectors, and signals from each sector are transmitted to each antenna of the HAP, so that the signals are not adjacent. Further, the HAP decodes the overlapping information of each sector. Next, power allocation is optimized by sector. To optimize power allocation, a constrained optimization problem is formulated and then converted into a nonconstraint optimization problem using the interior penalty method. The optimal solution derives the maximal value to the problem. Power for each sector is optimally allocated according to this optimal solution. Under this consideration, sum-throughput maximization is performed by optimally allocating DL energy beamforming by sector. We analyzed sum throughput and fairness, and then compared them according to the number of sectors. Performance results show that the proposed optimal power allocation by sector using hybrid SDMA/NOMA outperforms the existing equal power allocation by sector in terms of the sum throughput while fairness is also maintained. Moreover, the performance difference between the hybrid approach and SDMA, which optimally allocates power by sector, was about 1.4 times that of sum throughput on average, and the hybrid approach was dominant. There was also no difference in fairness performance.

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Fokin, Grigoriy, e Dmitriy Volgushev. "Model for Interference Evaluation in 5G Millimeter-Wave Ultra-Dense Network with Location-Aware Beamforming". Information 14, n. 1 (9 gennaio 2023): 40. http://dx.doi.org/10.3390/info14010040.

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Location-Aware Beamforming (LAB) in Ultra-Dense Networks (UDN) is a breakthrough technology for 5G New Radio (NR) and Beyond 5G (B5G) millimeter wave (mmWave) communication. Directional links with narrow antenna half-power beamwidth (HPBW) and massive multiple-input multiple-output (mMIMO) processing systems allows to increase transmitter and receiver gains and thus facilitates to overcome high path loss in mmWave. Well known problem of pencil beamforming (BF) is in construction of precoding vectors at the transmitter and combining vectors at the receiver during directional link establishing and its maintaining. It is complicated by huge antenna array (AA) size and required channel state information (CSI) exchange, which is time consuming for vehicle user equipment (UE). Knowledge of transmitter and receiver location, UE or gNodeB (gNB), could significantly alleviate directional link establishment and space division multiple access (SDMA) implementation. Background of SDMA is in efficient maintenance of affordable level of interference, and the purpose of this research is in signal-to-interference ratio (SIR) evaluation in various 5G UDN scenarios with LAB. The method, used to evaluate SIR, is link level simulation, and results are obtained from publicly released open-source simulator. Contribution of research includes substantiation of allowable UE density, working with LAB. Practical implications include recommendations on terrestrial and angular separation of two UE in 5G UDN scenarios.

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Li, Fangwei, Yue Wu, Yifang Nie e Ce Shi. "Time Allocation and Optimization in Time-Reversal Wireless Powered Communication Networks". International Journal of Antennas and Propagation 2020 (22 luglio 2020): 1–8. http://dx.doi.org/10.1155/2020/8906438.

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This paper studies optimal resource allocation in the wireless powered communication networks (WPCN) combined with time reversal (TR) in which one hybrid access point (H-AP) broadcasts constant wireless energy to a set of distributed users in the downlink (DL) and receives information from the users via space division multiple access (SDMA) in the uplink (UL). Inevitable interferences will occur when users transmit information in the UL simultaneously and the special space-time focusing of TR is used to suppress the interferences. An efficient protocol is proposed to support wireless energy transfer (WET) and TR in the DL and wireless information transmission in the UL for the proposed TR-WPCN. We optimize the time allocations to the H-AP for DL WET, DL TR, and UL WIT to maximize the sum throughput. Due to the nonconvexity of the studied optimization problem, we optimize variables successively, where the nonconvex optimization problem is transformed into the convex optimization problem. The approximate convex optimization problem can then be solved iteratively combined with the dichotomy method. Simulation results show that the proposed scheme can effectively suppress interferences and improve system performance.

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Morab, Feroz, Rajeshwari Hegde e Veena N. Hegde. "High Resolution Detection, Estimation and Location Using GTF DoA Method for Smart Antenna System". Traitement du Signal 39, n. 3 (30 giugno 2022): 1039–50. http://dx.doi.org/10.18280/ts.390332.

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Accommodating multiple users within the limited available bandwidth and providing the same Quality of Service (QoS) to all the users is a challenging task. Channel capacity can be increased by using the Spatial Division Multiple Access (SDMA) technique. Smart Antenna Systems are used to implement the SDMA technique in Real-Time and it also helps in finding the high-resolution Direction of Arrival (DoA) detection of the desired mobile users. In this paper novel Gaussian Triangular Factor (GTF) method is proposed for the detection of the desired mobile users from the 3-D spatial domain. This method is based on vector subspaces, which perform the triangular decomposition of the entire Eigenspace into the Lower Element Factor (LEF) and Upper Element Factor (UEF). These are then supplied for the computation of the power spectrum where peaks represent the detected locations of the desired mobile users in the 3-D spatial field. The proposed method was able to detect all the desired users, which were spaced nearer or far apart spatially, it provided high-quality detection regardless of the number of antenna elements used at the Base Station (BS). The GTF Method was able to detect all the desired users under the presence of heavy noise, fading, and interference. It was able to suppress the side lobes, back lobes, and grating lobes thus immensely improving the detection quality, detection range, system power consumption, detection efficiency, and effectiveness. The proposed GTF method was compared with several existing methods and it provided the best results for different performance parameters like Detection Error, Resolution, Time Complexity, and Disturbance Error.

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Fokin, G. "Location Aware Beamforming in Millimeter-Wave Band Ultra-Dense Radio Access Networks. Part 2. Model of a Set of Radio Links". Proceedings of Telecommunication Universities 9, n. 5 (14 novembre 2023): 43–64. http://dx.doi.org/10.31854/1813-324x-2023-9-5-43-64.

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The second part of the study of beamforming issues, based on positioning in ultra-dense millimeter wave radio access networks, is devoted to the formalization and software implementation of a complex simulation model of the functioning of a set of directional radio links. Each directional radio link between a base station (gNodeB – gNB), equipped with an antenna array, and a user equipment (UE), operating in omnidirectional mode, is formed according to the location of the UE, known at the gNB. The set of gNB→UE directional radio links, simultaneously operating in a common frequency range, is studied as a set of traffic beams, that implement space division multiple access (SDMA). Spatial multiplexing is implemented through three-dimensional beamforming at the gNB and makes it possible to compensate for propagation losses and high levels of interference. In the first part of the study, it was shown that the problem of practical implementation of SDMA in ultra-dense radio access networks is a significant (tens of dB) spread in the signal to interference plus noise ratio (SINR), depending on the arrangement of two devices. The purpose of this study is to establish the dependence of SINR on 1) the beamwidth of the gNB sector in the direction of the user equipment in the radio link of the signal of interest (SOI); 2) uncertainty of the UE location; 3) interference from radio links of signal not of interest (SNOI): a) within its sector, b) other sectors of its cell and c) other cells in the network. The simulation model developed and implemented in software in this work for the first time made it possible to establish the interdependence of the UE positioning error factors and the required width of the traffic beam for its service. In particular, it was found, that as the positioning error decreases from 10 to 1 m, the required beam width in the horizontal and vertical planes narrows to 3 °, which makes it possible to increase the SINR to 25 dB. A simultaneous transmission multiplexing study showed that for 64 spatially multiplexed UEs, as the cell size increases from 20 to 300 m, the SINR increases by approximately 30 dB, subject to a beamwidth constraint of 3°. Unlike similar studies, in this model, the contribution from interference from simultaneously operating traffic beams within its sector, other sectors of its cell and other cells in the network is shown separately for the first time, which allows to differentiate the origin of interference and use scientifically based beamwidth control for their compensation.

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THAZEEN, SADIYA, e Srikantaswamy MALLIKARJUNASWAMY. "THE EFFECTIVENESS OF 6T BEAMFORMER ALGORITHM IN SMART ANTENNA SYSTEMS FOR CONVERGENCE ANALYSIS". IIUM Engineering Journal 24, n. 2 (4 luglio 2023): 100–116. http://dx.doi.org/10.31436/iiumej.v24i2.2730.

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Recently, the need for more capacity in wireless networks has motivated this current research towards the creation of standards and algorithms that selectively take advantage of space. The development of smart antenna arrays and related beamforming algorithms has received a lot of attention. Cell Planning is an important process in networking, which is used to ensure coverage and avoid interference. Also, cell planning plays a vital role in the placement of base stations in a network. The communication between the base station (BS) and mobile station can happen either using a single antenna or an array of antenna elements. In the case of using a single antenna, if the Electromagnetic (EM) wave has low SNR, then BS cannot decode the data and drops the signal. Conversely, when an array is used, a signal with low SNR also falls on the base station, and due to multiple delayed copies of the same signal, the data gets decoded successfully. With Space Division Multiple Access (SDMA), the frequencies allotted for mobile communication are reused to provide channel access to multiple users at the same time preserving the allowable reuse distance in network architecture, thus increasing the channel capacity and facilitating multiple users separated by a distance at the same time with frequency reuse. The smart antenna system at the base station performs the transceiver function. The transmission phase uses the output from the reception i.e., the detected user direction radiates a beam towards the desired user for communication to narrow the beam. The proposed 6T Beamformer method is a six-tap-based system with three taps having fixed step sizes and the other three having variable step sizes. With the execution of each tap or module, better convergence and quality of service are achieved. In the result analysis, the proposed method is compared with existing high-performing algorithms like LMS, Griffiths, and VSSLMS against Mean Square Error (MSE) to show that it converges faster at the 9th iteration which is better than others in all the probabilities. ABSTRAK: Dewasa ini, keperluan terhadap lebih kapasiti dalam rangkaian tanpa wayar menjadi motivasi kepada kajian terkini dalam membentu piawai dan algoritma yang menjimatkan ruang. Pembangunan tata susun antena pintar dan algoritma pembentukan pancaran telah mendapat perhatian ramai. Merancang sel adalah proses penting dalam jaringan, bagi memastikan liputan terhasil dan mengelak dari gangguan. Juga, merancang sel memainkan peranan penting dalam menempatkan tapak stesen dalam rangkaian. Komunikasi antara stesen pusat (BS) dan stesen bergerak dapat berlaku samada menggunakan antena tunggal atau elemen tata susunan antena. Dalam kes antena tunggal, jika gelombang Elektromagnetik (EM) mempunyai SNR rendah, BS tidak dapat menafsirkan kod data dan signal akan terabai. Sebaliknya, apabila susun atur digunakan, signal dengan gelombang SNR rendah akan terus ke stesen pusat dan disebabkan beberapa gelombang sama yang tertunda, data dapat ditafsir dengan sempurna. Melalui Capaian Pelbagai Pembahagi Ruang (SDMA), frekuensi yang ditimbulkan bagi komunikasi bergerak telah diguna balik bagi menyediakan kemasukan saluran kepada pelbagai pengguna pada waktu sama memelihara jarak guna balik yang dibenarkan dalam binaan rangkaian, oleh itu menambah kapasiti saluran dan membantu gandaan pengguna yang dipisahkan oleh jarak dengan kekerapan guna balik pada masa sama. Sistem antena pintar di stesen pusat pula menjalankan fungsi pemancar. Fasa pemancaran ini menggunakan pengeluaran dari penerima iaitu, pengguna yang dikesan dari arah pancaran, akan memancarkan gelombang kepada pengguna yang memerlukan komunikasi, ini dapat mengecilkan jarak pancaran. Kaedah yang dicadangkan ini menghasil pancaran 6T iaitu sistem berdasarkan-enam-tap di mana tiga tap mempunyai saiz langkah yang tetap dan tiga lagi mempunyai saiz langkah berubah. Dengan pelaksanaan ini setiap tap atau modul mempunyai penumpuan yang lebih baik dan servis yang berkualiti terhasil. Dapatan kajian menunjukkan, kaedah yang dicadangkan dapat dibandingkan dengan algoritma berprestasi tinggi sedia ada seperti LMS, Griffiths, dan VSSLMS berbanding min kuasa dua ralat (MSE) bagi menunjukkan ia tertumpu lebih laju pada iterasi ke 9, iaitu lebih baik daripada ke semua kebarangkalian.

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Morab, Feroz, Rajeshwari Hegde e Veena N. Hegde. "Detection, Estimation and Radiation Formation Using Smart Antennas for the Spatial Location". Traitement du Signal 39, n. 1 (28 febbraio 2022): 389–98. http://dx.doi.org/10.18280/ts.390141.

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The Electromagnetic (EM) waves are impinging on the base station from all the directions, Equally Spaced Uniform Linear Antenna Array (ESULA) are used to process these incoming EM waves to Detect and Estimate the directions of the mobile transmitters. After the process of Detection and Estimation, Electronic Beamforming is used to provide the narrow sharper beam towards the detected user. This Detection, Estimation and Beamforming plays a key role in variety of use cases like Radar, Wireless Communication and Sonar based systems. Smart Antenna Systems are implemented using two strategies namely Direction of Arrival (DoA) and Beamforming (BF). Direction of Arrival is a mechanism of Detecting and Estimating the directions of the mobile transmitters. Beamforming on the other hand is a process of transmission of the EM waves towards the source in a specific direction and providing the Spectral Nulls to other Interfering users. To increase the user capacity and to enhance the user experience Spatial Location based Spatial Division Multiple Access (SDMA) technology is used. To improve the overall performance of the smart antenna systems energy and packet delivery is majorly focused on specific source directions rather than using blind transmission strategy. In this paper performance analysis of algorithms for Direction of Arrival methods as well as the Beamforming methods have been performed. Experimental simulations are conducted and comparison is done with respect to Bias, Resolution and Time complexity for the Direction of Arrival methods. Noise Subspace Method (NSM) DoA algorithm consistently delivered the optimal bias, high resolution detection of the user location in spatial domain and provided lesser time complexity for both the scenarios which uses fewer antenna elements or larger number of antenna array elements at the base station. Similarly for the case of Beamforming methods the Mean Square Error and Beam-directions have been compared.

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Miniscalco, William J., e Steven A. Lane. "Optical Space-Time Division Multiple Access". Journal of Lightwave Technology 30, n. 11 (giugno 2012): 1771–85. http://dx.doi.org/10.1109/jlt.2012.2189935.

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Sami Khafaga, Doaa, Mohammad Zubair Khan, Muhammad Awais Javed, Amel Ali Alhussan e Wael Said. "Space Division Multiple Access for Cellular V2X Communications". Computers, Materials & Continua 73, n. 1 (2022): 1195–206. http://dx.doi.org/10.32604/cmc.2022.028280.

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Choi, Wan, Antonio Forenza, Jeffrey G. Andrews e Robert W. Heath. "Opportunistic Space-Division Multiple Access With Beam Selection". IEEE Transactions on Communications 55, n. 12 (dicembre 2007): 2371–80. http://dx.doi.org/10.1109/tcomm.2007.910702.

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Xiang, Ji-ying. "Non-ideal space division multiple access and its application". Frontiers of Information Technology & Electronic Engineering 19, n. 3 (marzo 2018): 357–66. http://dx.doi.org/10.1631/fitee.1700827.

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Cavalcanti, R. P., e M. T. Romano. "Blind multiuser detection in space division multiple access systems". Annales Des Télécommunications 54, n. 7-8 (luglio 1999): 411–19. http://dx.doi.org/10.1007/bf02997763.

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Suard, B., Guanghan Xu, Hui Liu e T. Kailath. "Uplink channel capacity of space-division-multiple-access schemes". IEEE Transactions on Information Theory 44, n. 4 (luglio 1998): 1468–76. http://dx.doi.org/10.1109/18.681322.

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He, Chong, Xianling Liang, Bin Zhou, Junping Geng e Ronghong Jin. "Space-Division Multiple Access Based on Time-Modulated Array". IEEE Antennas and Wireless Propagation Letters 14 (2015): 610–13. http://dx.doi.org/10.1109/lawp.2014.2373431.

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Demmerle, F., e W. Wiesbeck. "A biconical multibeam antenna for space-division multiple access". IEEE Transactions on Antennas and Propagation 46, n. 6 (giugno 1998): 782–87. http://dx.doi.org/10.1109/8.686762.

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Hefnawi, Mostafa. "SER Performance of Large Scale OFDM-SDMA Based Cognitive Radio Networks". International Journal of Antennas and Propagation 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/594282.

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This paper proposes an adaptive large scale multiple input multiple output-beamforming scheme (LSMIMO-BF) for uplink (UL) access in broadband wireless cognitive networks with multiple primary users (PUs) and secondary users (SUs) sharing the same spectrum and employing orthogonal frequency-division multiplexing (OFDM). The proposed algorithm seeks the optimal transmit/receive weight vectors that maximize the UL MIMO channel capacity for each cognitive user while controlling the interference levels to PUs. Under the assumption of very large number of antennas at the base station, a closed-form expression for the symbol error rate (SER) performance of the cognitive LSMIMO-OFDM system is derived and compared with the one based on conventional beamforming schemes such as MIMO-maximum ratio combining (MIMO-MRC). The analysis and simulation show that when SUs are transmitting with the proposed constrained capacity-aware (CCA) scheme, the total interference level at the primary base station is reduced and the SER of PUs is improved compared to the case when the secondary network is using conventional MIMO-MRC. It was also shown that, as the number of base station antennas becomes larger, the constraints imposed by the primary network could be relaxed and the symbol error rate (SER) of SUs is improved without harming the PUs performance.

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29

Pao, Wei-Chen, Yung-Fang Chen, Wen-Ting Lou e Dah-Chung Chang. "Resource allocation for multiple input multiple output-orthogonal frequency division multiplexing -based space division multiple access systems". IET Communications 8, n. 18 (18 dicembre 2014): 3424–34. http://dx.doi.org/10.1049/iet-com.2014.0104.

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30

Kolyadenko, Yu Yu, e A. M. Alali. "SPACE-TIME DIVISION MULTIPLE ACCESS TO LTE NETWORK BASE STATIONS". Telecommunications and Radio Engineering 74, n. 19 (2015): 1737–43. http://dx.doi.org/10.1615/telecomradeng.v74.i19.60.

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31

LEE, M. W., C. MUN, D. H. KIM e J. G. YOOK. "Codebook Based Space Division Multiple Access with Partial Side Information". IEICE Transactions on Communications E91-B, n. 9 (1 settembre 2008): 3017–20. http://dx.doi.org/10.1093/ietcom/e91-b.9.3017.

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32

Huang, Kaibin, Robert W. Heath e Jeffrey G. Andrews. "Space Division Multiple Access With a Sum Feedback Rate Constraint". IEEE Transactions on Signal Processing 55, n. 7 (luglio 2007): 3879–91. http://dx.doi.org/10.1109/tsp.2007.894245.

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33

Barnett, Lewis. "The space division multiple access protocol: asynchronous implementation and performance". Computer Communications 21, n. 3 (marzo 1998): 227–42. http://dx.doi.org/10.1016/s0140-3664(97)00184-9.

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34

GÖRMÜŞ, Sedat, e Sercan KÜLCÜ. "Enabling space time division multiple access in IETF 6TiSCH protocol". TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES 27, n. 6 (26 novembre 2019): 4151–66. http://dx.doi.org/10.3906/elk-1903-127.

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35

Yin, Jingwei, Pengyu Du, Guang Yang e Huanling Zhou. "Space-division multiple access for CDMA multiuser underwater acoustic communications". Journal of Systems Engineering and Electronics 26, n. 6 (dicembre 2015): 1184–90. http://dx.doi.org/10.1109/jsee.2015.00129.

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36

Li, Jun, Miaowen Wen, Xueqin Jiang e Wei Duan. "Space-Time Multiple-Mode Orthogonal Frequency Division Multiplexing With Index Modulation". IEEE Access 5 (2017): 23212–22. http://dx.doi.org/10.1109/access.2017.2761845.

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37

INAYOSHI, Hiromichi, e Akihiko SUGIURA. "A study of communication breaking space using code division multiple access". IEEJ Transactions on Electronics, Information and Systems 117, n. 5 (1997): 660–61. http://dx.doi.org/10.1541/ieejeiss1987.117.5_660.

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38

Sung-Man Kim, Sung-Man Kim, e Hyun-Jun Lee Hyun-Jun Lee. "Visible light communication based on space-division multiple access optical beamforming". Chinese Optics Letters 12, n. 12 (2014): 120601–4. http://dx.doi.org/10.3788/col201412.120601.

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39

Noam, Yair, Alexandros Manolakos e Andrea J. Goldsmith. "Null Space Learning With Interference Feedback for Spatial Division Multiple Access". IEEE Transactions on Wireless Communications 13, n. 10 (ottobre 2014): 5699–715. http://dx.doi.org/10.1109/twc.2014.2336233.

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40

Yue Wu, Tao Cui e C. Tellambura. "Optimal low-complexity detection for space division multiple access wireless systems". IEEE Communications Letters 10, n. 3 (marzo 2006): 156–58. http://dx.doi.org/10.1109/lcomm.2006.1603369.

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41

Liu, Jiang, Jin Sando, Shigeru Shimamoto, Chiemi Fujikawa e Kashiko Kodate. "Experiment on space and time division multiple access scheme over free space optical communication". IEEE Transactions on Consumer Electronics 57, n. 4 (novembre 2011): 1571–78. http://dx.doi.org/10.1109/tce.2011.6131127.

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42

Yonis, Aws Zuheer, e Khalid Khalil Mohammed. "Investigation of pattern division multiple access technique in wireless communication networks". Indonesian Journal of Electrical Engineering and Computer Science 26, n. 1 (1 aprile 2022): 296. http://dx.doi.org/10.11591/ijeecs.v26.i1.pp296-303.

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Abstract (sommario):

Recently, <span>pattern division multiple access (PDMA) is a non-orthogonal multiple access system that is now being developed in next-generation telecoms to address the requirement for mass connectivity. The core premise of non-orthogonal multiple access is to simultaneously serve multiple users with varying power levels across the same spectrum resources such as time, frequency, code, as well as space with minimal inter-user interference. A simulation analysis of significant technology enhancements focusing on PDMA aims to describe the benefits of the two plans now being examined by the third-generation partnership project for 5G technologies, namely filtered orthogonal frequency division multiplexing (F-OFDM) and windowed orthogonal frequency division multiplexing (W-OFDM), and to compare them to alternative modulation processes such as 16, 32, and 128 modulations. The research results explained the PDMA is less bit error rate used in multiple access technologies compare with W-OFDM and F-OFDM.</span>

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43

Liu, Yusha, Luping Xiang, Lie-Liang Yang e Lajos Hanzo. "Space-Time Coded Generalized Spatial Modulation for Sparse Code Division Multiple Access". IEEE Transactions on Wireless Communications 20, n. 8 (agosto 2021): 5359–72. http://dx.doi.org/10.1109/twc.2021.3067376.

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44

Li, Yao, Adolf W. Lohmann e Satish B. Rao. "Free-space optical mesh-connected bus networks using wavelength-division multiple access". Applied Optics 32, n. 32 (10 novembre 1993): 6425. http://dx.doi.org/10.1364/ao.32.006425.

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45

Chen, Zhe, Dushyantha A. Basnayaka e Harald Haas. "Space Division Multiple Access for Optical Attocell Network Using Angle Diversity Transmitters". Journal of Lightwave Technology 35, n. 11 (1 giugno 2017): 2118–31. http://dx.doi.org/10.1109/jlt.2017.2670367.

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46

Dahman, Ghassan, Roshdy M. Hafez e Robert C. Bultitude. "Angle-of-departure-aided opportunistic space-division multiple access for MIMO applications". IEEE Transactions on Wireless Communications 9, n. 4 (aprile 2010): 1303–7. http://dx.doi.org/10.1109/twc.2010.04.091074.

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47

Mundarath, Jayakrishnan, e Jayesh Kotecha. "Optimal receive array beamforming for non-collaborative MIMO space division multiple access". IEEE Transactions on Communications 58, n. 1 (gennaio 2010): 218–27. http://dx.doi.org/10.1109/tcomm.2010.01.070174.

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48

Li, Y., T. Jiang e J. Sharony. "Massively parallel free-space optical Clos network using wavelength-division multiple access". Electronics Letters 28, n. 21 (1992): 2001. http://dx.doi.org/10.1049/el:19921283.

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49

Wu, Wei-Chiang. "Robust pre-filtering based space division multiple access over multi-path channels". Transactions on Emerging Telecommunications Technologies 26, n. 3 (7 maggio 2013): 403–13. http://dx.doi.org/10.1002/ett.2634.

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50

Kim, Taehwi, e Moonsik Min. "A Study on Determining the Optimal Feedback Rate in Distributed Block Diagonalization with Limited Feedback for Dense Cellular Networks". Mathematics 12, n. 3 (31 gennaio 2024): 460. http://dx.doi.org/10.3390/math12030460.

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Abstract (sommario):

In this study, we explore a downlink cellular network where each base station (BS) engages in simultaneous communication with multiple users through spatial division multiple access (SDMA). The positions of both BSs and users are established through independent random point processes, effectively representing the cellular network. SDMA utilizes block diagonalization (BD) at each BS, employing multiple receive antennas for each user. To implement BD, users quantize and provide feedback on their downlink channels to their respective BSs. The net spectral efficiency, measuring the effective rate accounting for both downlink and uplink resource usage, serves as a performance metric. In prior research, the optimal feedback rate in terms of maximizing net spectral efficiency has been approximated in this scenario. The corresponding approximations effectively illustrate the asymptotic behavior of the optimal number as a function of the length of the coherent channel block. However, the accuracy of the approximation diminishes when the length of the coherent channel block is relatively small. Given that the length of the coherent channel block can assume relatively small values depending on wireless environments, achieving a precise estimate across the entire range of the coherent block length holds significant importance. Consequently, this paper focuses primarily on enhancing the accuracy of the approximation for the optimal feedback rate. In order to achieve a more precise estimation, we analyze the derivative of the net spectral efficiency, which encompasses two functions that demonstrate distinct growth rates. In contrast to prior studies, both functions are rigorously approximated through mathematical analysis. As a result, the proposed approximation significantly improves the accuracy compared to previous studies, particularly when dealing with short coherent channel block lengths. Moreover, this approximation generally achieves near-optimal performance, regardless of system parameters.

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