Perancangan Sistem Komunikasi MIMO 2×2 dan Implementasi Sistem Komunikasi SISO Berbasis WARP

Teknologi MIMO digunakan untuk meningkatkan kapasitas sistem dan laju data pada sistem komunikasi wireless dengan memanfaatkan penggunaan space time diversity. Salah satu skema space time yang terkenal pada MIMO adalah skema space time Alamouti. Beberapa modul test-bed telah dibuat untuk mengimplementasikan sistem komunikasi wireless seperti Wireless Open Access Research Platform (WARP). Platform WARP  menawarkan sumber daya untuk mengimplementasikan algoritma nirkabel canggih pada semua layer jaringan. Penelitian ini melakukan perancangan implementasi sistem komunikasi MIMO 2×2 menggunakan skema Alamouti berbasis WARP, simulasi sistem komunikasi MIMO 2×2 Alamouti menggunakan MATLAB serta implementasi sistem komunikasi SISO. Metode pengukuran yang diusulkan pada makalah ini adalah menghasilkan nilaibit error rate (BER) terhadap perubahan jarak antar node (meter) dan kapasitas sistem MIMO Alamouti 2×2 ve sus jarak antar node (meter) untuk MIMO dan nilai BER untuk SISO. Hasil yang telah diperoleh pada penelitian ini adalah simulasi sistem komunikasi MIMO 2x2 menggunakan skema Alamouti menggunakan MATLAB. Hasil dari simulasi berupa grafik perbandingan bit error rate (dB) dan Eb/No serta nilai BER dari implementasi sistem komunikasi SISO

MIMO TECHNOLOGY FOR WIRELESS COMMUNICATION AND WIRELESS COMPUTER NETWORKING

The demand of wireless communication in the field of Wireless Computer networking and mobile phones(communications) is constantly growing and need the tether less connectivity. The major limitations to this growth is the disadvantages of traditional wireless communication System due to the limitations of available frequency resources, Bandwidth, channel capacity, complexity, reliability, transmission data rate and physical areas. This paper addresses the overview of new technology Multi-Input-Multi-Output (MIMO) for wireless Communication and Wireless Computer networking system will be much more efficient to meet the heavy demand of Wireless communication in available limited frequency resources. MIMO channel is frequency selective (multipath) and is known to boost channel capacity for high-data rate transmissions, low power implementation, sophisticated signal processing algorithm. The FPGA based coding techniques will reduce the size, complexity and increase the reliability of connectivity

Hardware implementation of multiple-input multiple-output transceiver for wireless communication

This dissertation proposes an efficient hardware implementation scheme for iterative multi-input multi-output orthogonal frequency-division multiplexing (MIMO-OFDM) transceiver. The transmitter incorporates linear precoder designed with instantaneous channel state information (CSI). The receiver implements MMSE-IC (minimum mean square error interference cancelation) detector, channel estimator, low-density parity-check (LDPC) decoder and other supporting modules. The proposed implementation uses QR decomposition (QRD) of complex-valued matrices with four co-ordinate rotation digital computer (CORDIC) cores and back substitution to achieve the best tradeoff between resource and throughput. The MIMO system is used in field test and the results indicate that the instantaneous CSI varies very fast in practices and the performance of linear precoder designed with instantaneous CSI is limited. Instead, statistic CSI had to be used. This dissertation also proposes a higher-rank principle Kronecker model (PKM). That exploits the statistic CSI to simulate the fading channels. The PKM is constructed by decomposing the channel correlation matrices with the higher-order singular value decomposition (HOSVD) method. The proposed PKM-HOSVD model is validated by extensive field experiments conducted for 4-by-4 MIMO systems in both indoor and outdoor environments. The results confirm that the statistic CSI varies slowly and the PKM-HOSVD will be helpful in the design of linear precoders. --Abstract, page iv

CORDICのハードウェア構成及び応用に関する研究

電気通信大学201

REAL-TIME ADAPTIVE PULSE COMPRESSION ON RECONFIGURABLE, SYSTEM-ON-CHIP (SOC) PLATFORMS

New radar applications need to perform complex algorithms and process a large quantity of data to generate useful information for the users. This situation has motivated the search for better processing solutions that include low-power high-performance processors, efficient algorithms, and high-speed interfaces. In this work, hardware implementation of adaptive pulse compression algorithms for real-time transceiver optimization is presented, and is based on a System-on-Chip architecture for reconfigurable hardware devices. This study also evaluates the performance of dedicated coprocessors as hardware accelerator units to speed up and improve the computation of computing-intensive tasks such matrix multiplication and matrix inversion, which are essential units to solve the covariance matrix. The tradeoffs between latency and hardware utilization are also presented. Moreover, the system architecture takes advantage of the embedded processor, which is interconnected with the logic resources through high-performance buses, to perform floating-point operations, control the processing blocks, and communicate with an external PC through a customized software interface. The overall system functionality is demonstrated and tested for real-time operations using a Ku-band testbed together with a low-cost channel emulator for different types of waveforms

Power allocation and linear precoding for wireless communications with finite-alphabet inputs

This dissertation proposes a new approach to maximizing data rate/throughput of practical communication system/networks through linear precoding and power allocation. First, the mutual information or capacity region is derived for finite-alphabet inputs such as phase-shift keying (PSK), pulse-amplitude modulation (PAM), and quadrature amplitude modulation (QAM) signals. This approach, without the commonly used Gaussian input assumptions, complicates the mutual information analysis and precoder design but improves performance when the designed precoders are applied to practical systems and networks. Second, several numerical optimization methods are developed for multiple-input multiple-output (MIMO) multiple access channels, dual-hop relay networks, and point-to-point MIMO systems. In MIMO multiple access channels, an iterative weighted sum rate maximization algorithm is proposed which utilizes an alternating optimization strategy and gradient descent update. In dual-hop relay networks, the structure of the optimal precoder is exploited to develop a two-step iterative algorithm based on convex optimization and optimization on the Stiefel manifold. The proposed algorithm is insensitive to initial point selection and able to achieve a near global optimal precoder solution. The gradient descent method is also used to obtain the optimal power allocation scheme which maximizes the mutual information between the source node and destination node in dual-hop relay networks. For point-to-point MIMO systems, a low complexity precoding design method is proposed, which maximizes the lower bound of the mutual information with discretized power allocation vector in a non-iterative fashion, thus reducing complexity. Finally, performances of the proposed power allocation and linear precoding schemes are evaluated in terms of both mutual information and bit error rate (BER). Numerical results show that at the same target mutual information or sum rate, the proposed approaches achieve 3-10dB gains compared to the existing methods in the medium signal-to-noise ratio region. Such significant gains are also indicated in the coded BER systems --Abstract, page iv-v

Etudes de récepteurs MIMO-LDPC itératifs

L objectif de cette thèse est l étude de récepteurs MIMO LDPC itératifs. Les techniques MIMO permettent d augmenter la capacité des réseaux sans fil sans la nécessité de ressources fréquentielles additives. Associées aux schémas de modulations multiporteuses CP-OFDM, les techniques MIMO sont ainsi devenues la pierre angulaire pour les systèmes sans fil à haute efficacité spectrale. La réception optimale peut être obtenue à l aide d une réception conjointe (Egalisation/Décodage). Étant très complexe, la réception conjointe n est pas envisagée et l égalisation et le décodage sont réalisés disjointement au coût d une dégradation significative en performances. Entre ces deux solutions, la réception itérative trouve son intérêt pour sa capacité à s approcher des performances optimales avec une complexité réduite. La conception de récepteurs itératifs pour certaines applications, de type WiFi à titre d exemple doit respecter la structure du code imposée par la norme. Ces codes ne sont pas optimisés pour des récepteurs itératifs. En observant l effet du nombre d' itérations dans le processus itératif, on montre par simulation que l ordonnancement des itérations décodage LDPC/Turbo-égalisation joue un rôle important dans la complexité et le délai du récepteur. Nous proposons de définir des ordonnancements permettant de réduire la complexité globale du récepteur. Deux approches sont proposées, une approche statique ainsi qu'une autre dynamique. Ensuite nous considérons un système multi-utilisateur avec un accès multiple par répartition spatiale. Nous étudions l intérêt de la réception itérative dans ce contexte tenant en compte la différence de puissance signale utile/interférence.The aim of this thesis is to address the design of iterative MIMO receivers using LDPC Error Correcting codes. MIMO techniques enable capacity increase in wireless networks with no additional frequency ressources. The associationof MIMO with multicarrier modulation techniques OFDM made them the cornerstone of emerging high rate wireless networks. Optimal reception can be achieved using joint detection and decoding at the expense of a huge complexity making it impractical. Disjoint reception is then the most used. The design of iterative receivers for some applications using LDPC codes like Wifi (IEEE 802.11n) is constrained by the standard code structure which is not optimized for such kind of receivers. By observing the effect of the number of iterations on performance and complexity we underline the interest of scheduling LDPC decoding iterations and turboequalization iterations. We propose to define schedules for the iterative receiver in order to reduce its complexity while preserving its performance. Two approaches are used : static and dynamic scheduling. The second part of this work is concerns Multiuser MIMO using Spatial Division Multiple Access. We explore and evaluate the interest of using iterative reception to cancel residual inter-user interference.PARIS-Télécom ParisTech (751132302) / SudocSudocFranceF