Rede neural de função de base radial de transmissão de fase complexa para decodificação mimo-ofdm massiva

Orientador: Dalton Soares ArantesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Os esquemas de transmissão MIMO (multiple-input multiple-output) se tornaram as técnicas escolhidas para aumentar a eficiência espectral em áreas congestionadas. No entanto, o projeto de receptores de baixo custo para canais MIMO continua sendo uma tarefa desafiadora. O detector de máxima verossimilhança pode atingir um desempenho excelente, geralmente o melhor, mas sua complexidade computacional é um fator limitante na implementação prática. Neste trabalho, um novo esquema MIMO é proposto com um algoritmo de decodificação pratico e viável baseado na PTRBFNN (rede neural de função de base radial de transmitância de fase). O esquema proposto atinge uma complexidade computacional bastante competitiva em relação à decodificação de Máxima Verossimilhança, aumentando substancialmente a aplicabilidade do algoritmo. Os resultados da simulação são apresentados para MIMO-OFDM sob desvanecimento Rayleigh em canais sem fio, para que uma comparação de desempenho justa com outras técnicas de referência possa ser estabelecidaAbstract: Multi-Input Multi-Output (MIMO) transmission schemes have become the techniques of choice for increasing spectral efficiency in bandwidth-congested areas. However, the design of cost-effective receivers for MIMO channels remains a challenging task. The maximum likelihood detector can achieve excellent performance, usually the best, but its computational complexity is a limiting factor in practical implementation. In this work, a new MIMO scheme is proposed with a practically feasible decoding algorithm based on the phase transmittance radial basis function neural network (PTRBFNN). The proposed scheme achieves a computational complexity that is quite competitive relative to the Maximum Likelihood decoding, thus substantially increasing the applicability of the algorithm. Simulation results are presented for MIMO-OFDM under wireless Rayleigh fading channels so that a fair performance comparison with other reference techniques can be establishedMestradoTelecomunicações e TelemáticaMestre em Engenharia Elétrica132545/2019-5CNP

Fast-Decodable Asymmetric Space-Time Codes from Division Algebras

Multiple-input double-output (MIDO) codes are important in the near-future wireless communications, where the portable end-user device is physically small and will typically contain at most two receive antennas. Especially tempting is the 4 x 2 channel due to its immediate applicability in the digital video broadcasting (DVB). Such channels optimally employ rate-two space-time (ST) codes consisting of (4 x 4) matrices. Unfortunately, such codes are in general very complex to decode, hence setting forth a call for constructions with reduced complexity. Recently, some reduced complexity constructions have been proposed, but they have mainly been based on different ad hoc methods and have resulted in isolated examples rather than in a more general class of codes. In this paper, it will be shown that a family of division algebra based MIDO codes will always result in at least 37.5% worst-case complexity reduction, while maintaining full diversity and, for the first time, the non-vanishing determinant (NVD) property. The reduction follows from the fact that, similarly to the Alamouti code, the codes will be subsets of matrix rings of the Hamiltonian quaternions, hence allowing simplified decoding. At the moment, such reductions are among the best known for rate-two MIDO codes. Several explicit constructions are presented and shown to have excellent performance through computer simulations.Comment: 26 pages, 1 figure, submitted to IEEE Trans. Inf. Theory, October 201

Circuit-Aware System Design Techniques for Wireless Communication

Thesis Supervisor: Gregory W. Wornell Title: ProfessorWhen designing wireless communication systems, many hardware details are hidden from the algorithm designer, especially with analog hardware. While it is difficult for a designer to understand all aspects of a complex system, some knowledge of circuit constraints can improve system performance by relaxing design constraints. The specifications of a circuit design are generally not equally difficult to meet, allowing excess margin in one area to be used to relax more difficult design constraints. We first propose an uplink/downlink architecture for a network with a multiple antenna central server. This design takes advantage of the central server to allow the nodes to achieve multiplexing gain by forming virtual arrays without coordination, or diversity gain to decrease SNR requirements. Computation and memory are offloaded from the nodes to the server, allowing less complex, inexpensive nodes to be used. We can further use this SNR margin to reduce circuit area and power consumption, sacrificing system capacity for circuit optimization. Besides the more common trans- mit power reduction, large passive analog components can be removed to reduce chip area, and bias currents lowered to save power at the expense of noise figure. Given the inevitable crosstalk coupling of circuits, we determine the minimum required crosstalk isolation in terms of circuit gain and signal range. Viewing the crosstalk as a static fading channel, we derive a formula for the asymptotic SNR loss, and propose phase randomization to reduce the strong phase dependence of the crosstalk SNR loss. Because the high peak to average power (PAPR) that results from multicarrier systems is difficult for analog circuits to handle, the result is low power efficiencies. We propose two algorithms, both of which can decrease the PAPR by 4 dB or more, resulting in an overall power reduction by over a factor of three in the high and low SNR regimes, when combined with an outphasing linear amplifier.MIT, the Semiconductor Research Corpo- ration and MARCO C2S2, and Lincoln Laboratory

Mobile and Wireless Communications

Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies

Circuit-aware system design techniques for wireless communication

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 211-218).When designing wireless communication systems, many hardware details are hidden from the algorithm designer, especially with analog hardware. While it is difficult for a designer to understand all aspects of a complex system, some knowledge of circuit constraints can improve system performance by relaxing design constraints. The specifications of a circuit design are generally not equally difficult to meet, allowing excess margin in one area to be used to relax more difficult design constraints. We first propose an uplink/downlink architecture for a network with a multiple antenna central server. This design takes advantage of the central server to allow the nodes to achieve multiplexing gain by forming virtual arrays without coordination, or diversity gain to decrease SNR requirements. Computation and memory are offloaded from the nodes to the server, allowing less complex, inexpensive nodes to be used. We can further use this SNR margin to reduce circuit area and power consumption, sacrificing system capacity for circuit optimization. Besides the more common transmit power reduction, large passive analog components can be removed to reduce chip area, and bias currents lowered to save power at the expense of noise figure. Given the inevitable crosstalk coupling of circuits, we determine the minimum required crosstalk isolation in terms of circuit gain and signal range.(cont.) Viewing the crosstalk as a static fading channel, we derive a formula for the asymptotic SNR loss, and propose phase randomization to reduce the strong phase dependence of the crosstalk SNR loss. Because the high peak to average power (PAPR) that results from multicarrier systems is difficult for analog circuits to handle, the result is low power efficiencies. We propose two algorithms, both of which can decrease the PAPR by 4 dB or more, resulting in an overall power reduction by over a factor of three in the high and low SNR regimes, when combined with an outphasing linear amplifier.by Everest Wang Huang.Ph.D

OSTBC MIMO Transceiver System For Radio Signal Propagation Challenges Over Irregular Terrain In The Northern Cape, South Africa

DissertationThe Northern Cape Province in South Africa, along the Orange River valley, has radio signal reception challenges due to high mountain ranges. The South African Electricity Authority- Eskom has High Voltage assets to monitor in this region. However, due to radio signal reception challenges, it is impossible to monitor their assets via the Supervisory Control and Data Acquisition (SCADA) system. This research aims at developing a Very-High Frequency Orthogonal Space – Time Block Code Multiple-In Multiple-Out (VHF OSTBC MIMO) transceiver simulation model over a Rayleigh fading channel to address the radio communication challenges along the Orange River. The transceiver simulation model will resemble the harsh multipath environment presented by the mountainous terrain in the Northern Cape Province. In environments with irregular terrain such as hills and mountains, the radio signal comes across phenomena such as reflection, refraction, diffraction and scattering. Therefore, the transmitted radio signal undergoes heavy fading and inter-symbol interference (ISI), thus negatively impacting radio link performance. However, the Multiple-input- multiple-output (MIMO) system, which uses multiple antennas both at the transmitter and receiver, takes advantage of this drawback and makes use of the high levels of multi-paths to operate at an optimum. MIMO creates spatial diversity which accounts for better radio link performance, it also yields increased capacity and improves Signal-to-Noise Ratio (SNR) while reducing bit errors. Therefore, MIMO is one of the systems of interest considered best to exploit in this research. Space- time coding (STC) has also been considered because of its ability to increase the reliability of the channel and for its signal decoding simplicity at the receiver. A suitable lower frequency band to use for this research was also investigated. The most attractive characteristic of the low frequency (LF) band that was sought after was its ability to easily diffract over large obstacles than higher frequencies. The Very High Frequency (VHF) band at 70 MHz was found to meet the requirements for the model used. Therefore, this dissertation presents the simulation results of a VHF OSTBC MIMO transceiver model over a Rayleigh fading channel that is typical of the mountainous regions of the Northern Cape Province in South Africa, to help overcome radio signal reception challenges. The following are the different component blocks that made up the model: Random Binary Generator (RBG), Quadrature Phase Shift Key (QPSK) Modulator, Orthogonal Space-Time Block Code (OSTBC) Encoder, Multiple-In Multiple-Out (MIMO) Rayleigh Fading Channel, Added White Gaussian Noise (AWGN), Orthogonal Space-Time Block Code (OSTBC) Decoder and a Quadrature Phase Shift Key (QPSK) Demodulator. The simulation results in this research were generated using the following software packages namely: Matlab/Simulink, Atoll Wireless Network and Pathloss 4 Network. The Matlab/Simulink software was used to determine the bit-error-rate (BER) performance of four different OSTBC MIMO systems, each using different antenna arrays. TheMatlab RF Propagation Tool-SiteViewer was used to generate coverage predictions and receive signal strength (RSS) levels of three VHF OSTBC MIMO systems operating at three different low VHF frequency bands. The Atoll Wireless Network software was used to generate coverage plot predictions. The Pathloss 4 software was used to generate Line of Sight (LoS) predictions. The results have shown that employing the low band VHF OSTBC MIMO transceiver system in irregular terrain environments can greatly improve radio signal reception, data speeds, bandwidth efficiency and link reliability