Les implants cochléaires sont des appareils destinés à la réhabilitationdes surdités profondes et totales. Ils assurent la stimulation du nerf auditif en plaçant des électrodes dans la cochlée. Différentes études ont été établis afin d’améliorer l’intelligibilité de la parole dans le bruit chez le patientporteur de cet appareil. Les techniques bilatérales et binaurales permettent dereproduire une audition binaurale, car les deux oreilles sont simulées (commepour les personnes normo-entendantes). Ainsi la localisation et la perceptiondes sons environnants sont améliorées par rapport à une implantationmonaurale. Toutefois, les capacit´es de reconnaissances des mots sont trèsvite limitées en pr´esence de bruits. Nous avons d´evelopp´es des techniquesde r´eduction de bruit afin d’augmenter les performances de reconnaissance.Des améliorations de 10% à 15% suivant les conditions ont été observées. Néanmoins, si la perception est améliorée par les algorithmes, ils focalisent sur une direction, et ainsi, la localisation est alors réduite à l’angle delocalisation. Une seconde étude a alors été effectuée pour mesurer l’effetdes algorithmes sur la localisation. Ainsi, le beamformer donne les meilleurs résultats de compréhension mais la moins bonne localisation. La ré-injectiond’un pourcentage du signal d’entrée sur la sortie a permis de compenser laperte de la localisation sans détériorer l’intelligibilité. Le résultat de ces deux expériences montre qu’il faut un compromis entre laperception et la localisation des sons pour obtenir les meilleures performances. / Cochlear implants are to sail for the rehabilitation of deep and totaldeafness. They provide stimulation of the auditory nerve by placing electrodesin the cochlea. Various studies have been established to improve thespeech intelligibility in noise in the patient of this device. Bilateral andbinaural techniques allow reproducing a binaural hearing, since both earsare simulated (as for normal hearing people). Thus localization and theperception of the surrounding sounds are improved from a monauralimplantation. However, the recognition of the words capabilities are limitedvery quickly in the presence of noise.We developed noise reduction techniquesto increase the performance of recognition. Improvements of 10% to 15%depending on the conditions were observed. Nevertheless, if the perception isenhanced by algorithms, they focus on a direction, and thus the location isthen reduced at the corner of localization. Then, a second study was madeto measure the effect of localization algorithms. Thus, the beamformer givesthe best results of understanding but the less good location. The re-injectionof a percentage of the input to the output signal helped offset the loss of thelocation without damaging the intelligibility.The result of these two experiments shows that it takes a compromisebetween perception and sound localization for best performance.

At the begining of this thesis radar theory and classification of radar systems is explained. Next part introduces antenna arrays with it’s parameters and possibilities. Main part contains design of digital beamformer on FPGA Cyclone V and it’s validation.

The master s thesis deals with the design of the beamsteering antenna. Methods of the beamsteering and the final antenna design are described. This antenna operates in the ISM band with the central frequency of 5,8 GHz. The antenna is designed in the CST Studio Suite 2020. Butler matrix was designed as a feed network implemented as substrate integrated waveguide. An array of patch antennas was used for radiation.

In the first part of the dissertation, we provide an extensive overview of sub-6 GHz wireless access technology known as massive multiple-input multiple-output (MIMO) systems, highlighting its benefits, deployment challenges, and the key enabling technologies envisaged for 5G networks. We investigate the fundamental issues that degrade the performance of massive MIMO systems such as pilot contamination, precoding, user scheduling, and signal detection. In the second part, we optimize the performance of the massive MIMO system by proposing several algorithms, system designs, and hardware architectures. To mitigate the effect of pilot contamination, we propose a pilot reuse factor scheme based on the user environment and the number of active users. The results through simulations show that the proposed scheme ensures the system always operates at maximal spectral efficiency and achieves higher throughput. To address the user scheduling problem, we propose two user scheduling algorithms bases upon the measured channel gain. The simulation results show that our proposed user scheduling algorithms achieve better error performance, improve sum capacity and throughput, and guarantee fairness among the users. To address the uplink signal detection challenge in the massive MIMO systems, we propose four algorithms and their system designs. We show through simulations that the proposed algorithms are computationally efficient and can achieve near-optimal bit error rate performance. Additionally, we propose hardware architectures for all the proposed algorithms to identify the required physical components and their interrelationships.

This master's thesis is focused on the noise source identification using microphone arrays and beamforming as the signal processing method. It describes parts of such a system and provides a comparison with other systems that serve a similar purpose (eg. NAH). Various types of microphone arrays are mentioned with their influence on the resulting ability to identify the noise source. We are further focusing on Delay-And-Sum technology, on which we are explaining the basic principles and constraints of beamforming. The practical part describes the implementation of the DAS method in MATLAB and C language, the specific structures of built microphone arrays and assembly of complete systems capable of identifying sources of noise. These systems were tested by performing a practical experiment. Achievements in the form of distribution maps of acoustic energy in the focused space are interpreted in the last chapter.

This thesis deals with processing signals from the microphone arrays for sound source localization. Compares different types of fields, such as cross-field and circular array. It is shown here how to implement Beamforming on FPGA and design of signal processing with a microphone array.

The availability of feedback from the receiver to the transmitter in a communication system can play a significant role. In this dissertation, our focus is specifically on binary or one-bit feedback. First, we study the problem of successive beam alignment for millimeter-wave channels where the receiver sends back only one-bit of information per beam sounding. The sparse nature of the channel allows us to interpret channel sounding as a form of questioning. By posing the alignment problem as a questioning strategy, we describe adaptive (closed-loop) and non-adaptive (open-loop) channel sounding techniques which are robust to erroneous feedback signals caused by noisy quantization. In the second part, we tightly characterize the capacity for two binary stochastic-adversarial mixed noise channels. Specifically, the transmitter (Alice) intends to convey a message to the receiver (Bob) over a binary symmetric channel (BSC) or a binary erasure channel (BEC) in the presence of an adversary (Calvin) who injects additional noise at the channel's input subject to a budget constraint. Calvin is online or causal in that at any point during the transmission, he can infer the bits being sent by Alice and those being received by Bob via a feedback link. Finally in the third part, we study the applicability of binary feedback for encoding and propose the framework of linearly adapting block feedback codes. We also prove a new result for Reed-Muller (RM) codes to demonstrate how an uncoded system can mimic a RM code under this framework, against remarkably large feedback delays.

This thesis examines the problem of providing high data-rate wireless connectivity to users in indoor environments. The goal is to be able to reach Gbps/user rates even when there are multiple users present. The technology that we study is to use the 60 GHz spectrum whose special propagation properties make it ideally suited to this task. The approaches developed include using multiple spatially distributed smart antennas in a room or multiple co-located antennas to provide coverage where needed and when needed. All the antennas are connected to a single access point which allows us to dynamically change spectrum and link allocation among the users (as they move or as their needs change). The innovations in this work include the exploitation of the special properties of 60 GHz and the corresponding design of algorithms for efficient spectrum allocation. We use detailed simulations to demonstrate that very high data rates are indeed achievable.

With the evolution in the telecommunication generations, more and more research is going on in the field of wireless communications. The purpose of these researches has always been to provide good network coverage across the region with higher data rates, accuracy and better performance. Control on coverage and performance has always been in focus and is achieved using better and better antennas. Research has brought us with a sophisticated approach on the control of the properties of the antennas – introduction to Smart Antennas. Smart antennas can be used to support any radio based telecommunication system in any band, with the same level of performance. Several techniques are used to get good performance out of the antennas’ system. One impressive way is the usage of multiple antennas techniques. The approach is to transmit and receive 2 or more unique data on a single radio channel. To increase the diversity gain with the use of multiple input multiple output (MIMO), OFDM is a good technology used at the physical layer. It provides robustness to frequency selective fading, high spectral efficiency and low computational complexity. So MIMO-OFDM generates a good basis for 3GPP (3rd Generation Partnership Project) and 4G telecommunication technologies as well as other wireless communications systems. With MIMO-OFDM as basis, different standards like WiMAX (Wireless Interoperability for Microwave Access) and LTE (Long Term Evolution) have been implemented now. The use of OFDM has some limitations when it is considered for uplink like high peak to average power ratio (PAPR), for which a new technique of using Single Carrier is considered for uplink. Single Carrier FDMA has same advantages as of OFDM with low PAPR. In this thesis, we investigate the smart antennas with its application as LTE with the study of MIMO-OFDM and Single Carrier FDMA Systems. Performance of MIMO OFDM and SC-FDMA is evaluated by using simulations on MATLAB.

Future 6G wireless communications network will increase the data capacity to unprecedented numbers and thus empower the deployment of new real-time applications. Millimeter-Wave (mmWave) band and Massive MIMO are considered as two of the main pillars of 6G to handle the gigantic influx in data traffic and number of mobile users and IoT devices. The small wavelengths at these frequencies mean that more antenna elements can be placed in the same area. Thereby, high spatial processing gains are achievable that can theoretically compensate for the higher isotropic path loss. The propagation characteristics at mmWave band, create sparse channels in typical scenarios, where only few paths convey significant power. Considering this feature, Hybrid (analog-digital) Beamforming introduces a new signal processing framework which enables energy and cost-efficient implementation of massive MIMO with innovative smart arrays. In this setup, the analog beamalignment via beam selection in link access phase, is the critical performance limiting step. Considering the variable operating condition in mmWave channels, a desirable solution should have the following features: efficiency in training (limited coherence time, delay constraints), adaptivity to channel conditions (large SNR range) and robustness to realized channels (LOS, NLOS, Multipath, non-ideal beam patterns). For the link access task, we present a new energy-detection framework based on variable length channel measurements with (orthogonal) beam codebooks. The proposed beam selection technique denoted as composite M-ary Sequential Competition Test (SCT) solves the beam selection problem when knowledge about the SNR operating point is not available. It adaptively changes the test length when the SNR varies to achieve an essentially constant performance level. In addition, it is robust to non-ideal beam patterns and different types of the realized channel. Compared to the conventional fixed length energy-detection techniques, the SCT can increase the training efficiency up to two times while reducing the delay if the channel condition is good. Having the flexibility to allocate resources for channel measurements through different beams adaptively in time, we improve the SCT to eliminate unpromising beams from the remaining candidate set as soon as possible. In this way, the Sequential Competition and Elimination Test (SCET) significantly further reduces training time by increasing the efficiency. The developed ideas can be applied with different codebook types considered for practical applications. The reliable performance of the beam selection technique is evident through experimental evaluation done using the state-of-the-art test-bed developed at the Vodafone Chair that combines a Universal Software Radio Peripheral (USRP) based platform with mmWave frontends.