Structure and Implementation of a SIMO Multi-Standard Multichannel SDR Receiver

International audienceThis article presents the structure of a multiantenna multi-channel and multi-standard receiver based on Software Defined Radio (SDR) concept. At this time our work is focused on 802.11g and 802.11b signals cohabiting in a 40 MHz frequency bandwidth around the 2.4 GHz RF carrier frequency. Using classical Single Input Multiple Output (SIMO) processing, these incoming signals are combined to increase transmission performances and to mitigate fading effect. Simulated and measured results of our structure are given and a description of the real proposed architecture is detailed

Coupled Simulation-Measurements Platform for the Evaluation of Frequency-Reuse in the 2.45 GHz ISM band for Multi-mode Nodes with Multiple Antennas

International audienceIn this paper we address the problem of efficiently evaluate performance of concurrent radio links on overlapped channels. In complex network topologies with various standards and frequency channels, simulating a realistic PHY layer communication is a key point. The presented coupled simulation-measurement platform offers a very promising way of rapidly modelling and validating effective performance of multi-mode, multi-channel and multi-antenna radio nodes. An accurate of radio channel is performed and then realistic performance with or without antenna processing is shown, verifying theoretical performance. Finally, available performance of concurrent communications on overlapped channels is exposed, showing that this approach is viable to enhance network capacity

Rethinking Wireless: Building Next-Generation Networks

We face a growing challenge to the design, deployment and management of wireless networks that largely stems from the need to operate in an increasingly spectrum-sparse environment, the need for greater concurrency among devices and the need for greater coordination between heterogeneous wireless protocols. Unfortunately, our current wireless networks lack interoperability, are deployed with fixed functions, and omit easy programmability and extensibility from their key design requirements. In this dissertation, we study the design of next-generation wireless networks and analyze the individual components required to build such an infrastructure. Re-designing a wireless architecture must be undertaken carefully to balance new and coordinated multipoint (CoMP) techniques with the backward compatibility necessary to support the large number of existing devices. These next-generation wireless networks will be predominantly software-defined and will have three components: (a) a wireless component that consists of software-defined radio resource units (RRUs) or access points (APs); (b) a software-defined backhaul control plane that manages the transfer of RF data between the RRUs and the centralized processing resource; and (c) a centralized datacenter/cloud compute resource that processes RF signal data from all attached RRUs. The dissertation addresses the following four key problems in next-generation networks: (1) Making Existing Wireless Devices Spectrum-Agile, (2) Cooperative Compression of the Wireless Backhaul, (3) Spectrum Coordination and (4) Spectrum Coordination.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/102341/1/zontar_1.pd

Spectrally and Energy Efficient Wireless Communications: Signal and System Design, Mathematical Modelling and Optimisation

This thesis explores engineering studies and designs aiming to meeting the requirements of enhancing capacity and energy efficiency for next generation communication networks. Challenges of spectrum scarcity and energy constraints are addressed and new technologies are proposed, analytically investigated and examined. The thesis commences by reviewing studies on spectrally and energy-efficient techniques, with a special focus on non-orthogonal multicarrier modulation, particularly spectrally efficient frequency division multiplexing (SEFDM). Rigorous theoretical and mathematical modelling studies of SEFDM are presented. Moreover, to address the potential application of SEFDM under the 5th generation new radio (5G NR) heterogeneous numerologies, simulation-based studies of SEFDM coexisting with orthogonal frequency division multiplexing (OFDM) are conducted. New signal formats and corresponding transceiver structure are designed, using a Hilbert transform filter pair for shaping pulses. Detailed modelling and numerical investigations show that the proposed signal doubles spectral efficiency without performance degradation, with studies of two signal formats; uncoded narrow-band internet of things (NB-IoT) signals and unframed turbo coded multi-carrier signals. The thesis also considers using constellation shaping techniques and SEFDM for capacity enhancement in 5G system. Probabilistic shaping for SEFDM is proposed and modelled to show both transmission energy reduction and bandwidth saving with advantageous flexibility for data rate adaptation. Expanding on constellation shaping to improve performance further, a comparative study of multidimensional modulation techniques is carried out. A four-dimensional signal, with better noise immunity is investigated, for which metaheuristic optimisation algorithms are studied, developed, and conducted to optimise bit-to-symbol mapping. Finally, a specially designed machine learning technique for signal and system design in physical layer communications is proposed, utilising the application of autoencoder-based end-to-end learning. Multidimensional signal modulation with multidimensional constellation shaping is proposed and optimised by using machine learning techniques, demonstrating significant improvement in spectral and energy efficiencies

Analysis of filtered OFDM for 5G

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Engenharia Elétrica, 2018.A quarta geração de comunicações móveis, 4G, proveu conexões com altas velocidades, taxas de dados e resiliência na última década. No entanto, novas tecnologias estão surgindo e estas popularizarão-se no futuro próximo. Tecnologias como veículos autônomos, monitoramento de saúde, jogos onlines e Internet das Coisas (IoT) demandarão altíssimas taxas de dados (20 Gbps), baixíssima latência (1 ms) e baixo consumo de energia. Para atender a estes requisitos, é esper- ada uma mudança de paradigma em telecomunicações. O OFDM filtrado (fOFDM) traz uma redução considerável das radiações fora de banda, possibilitando a divisão do espectro em sub- bandas, que possuem numerologias independentes e podem ser transmitidas sem a necessidade de sincronia global. Deste modo, esta forma de onda visa atender as mais heterogêneas aplicações na interface aérea da quinta geração (5G), além de aumentar a eficiência espectral dos sistemas de telecomunicações. Neste trabalho, o desempenho do fOFDM foi avaliado, por meio de simulações computacionais, sob diversas circunstâncias, tais como propagação com multipercurso, interferên- cia, transmissão assíncrona, diferentes filtros, etc. Os resultados destes estudos são comparados ao OFDM, para que se tenha uma melhor percepção das diferenças entre as duas tecnologias.The fourth generation of mobile communications (4G) provided high speed, high bit rate and resilient connections for the last decade. However, new technologies are appearing and they are expected to become popular in the near future. Technologies like autonomous vehicles, health care monitoring, online gaming and Internet of Things (IoT) will demand high bit rates (20 Gbps), ultra-low latency (1 ms) and low power consumption. In order to attend these requirements, a paradigm shift is expected in telecommunications. Filtered OFDM (fOFDM) brings a considerable out-of-band emission (OOBE) reduction, making it possible to divide the spectrum into sub- bands, which have independent numerology and may be transmitted without the need of global synchrony. Therefore, this waveform seeks to support the most heterogeneous applications, while also enhancing the system’s spectral efficiency. In this work, fOFDM’s performance was studied, by computational simulations, under diverse circumstances, e.g., multipath propagation, interference, asynchronous transmission, different filters, etc. The investigations results are compared to OFDM, in order to attain a better perception of the differences between the two technologies

Resource allocation and optimization techniques in wireless relay networks

Relay techniques have the potential to enhance capacity and coverage of a wireless network. Due to rapidly increasing number of smart phone subscribers and high demand for data intensive multimedia applications, the useful radio spectrum is becoming a scarce resource. For this reason, two way relay network and cognitive radio technologies are required for better utilization of radio spectrum. Compared to the conventional one way relay network, both the uplink and the downlink can be served simultaneously using a two way relay network. Hence the effective bandwidth efficiency is considered to be one time slot per transmission. Cognitive networks are wireless networks that consist of different types of users, a primary user (PU, the primary license holder of a spectrum band) and secondary users (SU, cognitive radios that opportunistically access the PU spectrum). The secondary users can access the spectrum of the licensed user provided they do not harmfully affect to the primary user. In this thesis, various resource allocation and optimization techniques have been investigated for wireless relay and cognitive radio networks

NOVEL OFDM SYSTEM BASED ON DUAL-TREE COMPLEX WAVELET TRANSFORM

The demand for higher and higher capacity in wireless networks, such as cellular, mobile and local area network etc, is driving the development of new signaling techniques with improved spectral and power efficiencies. At all stages of a transceiver, from the bandwidth efficiency of the modulation schemes through highly nonlinear power amplifier of the transmitters to the channel sharing between different users, the problems relating to power usage and spectrum are aplenty. In the coming future, orthogonal frequency division multiplexing (OFDM) technology promises to be a ready solution to achieving the high data capacity and better spectral efficiency in wireless communication systems by virtue of its well-known and desirable characteristics. Towards these ends, this dissertation investigates a novel OFDM system based on dual-tree complex wavelet transform (D

Interference Management Techniques for Cellular Wireless Communication Systems

The growing demand for higher capacity wireless networks can be met by increasing the frequency bandwidth, spectral efficiency, and base station density. Flexible spectrum access, multiantenna, and multicarrier techniques are key enablers in satisfying the demand. In addition, automation of tasks related to network planning, optimization, interference management, and maintenance are needed in order to ensure cost-efficiency. Effective, dynamic, and automated interference management tailored for bursty and local data traffic plays a central role in the task. Adjacent channel interference (ACI) management is an enabler for flexible spectrum use and uncoordinated network deployments. In this thesis the impact of ACI in local area time division duplex (TDD) cellular systems is demonstrated. A method is proposed where the transmitters optimize their transmitted spectral shape on-line, such that constraints on ACI induced by power amplifier non-linearity are met. The proposed method increases the fairness among spectrum sharing transceivers when ACI is a limiting factor. A novel interference-aware scheduling technique is proposed and analyzed. The technique manages co-channel interference (CCI) in a decentralized fashion, relying on beacon messages sent by data receivers. It is demonstrated that the proposed technique is an enabler for fair spectrum sharing among operators, independent adaptation of uplink/downlink switching points in TDD networks, and it provides overall more fair and spectrally efficient wireless access. Especially, the technique is able to improve the cell-edge throughput tremendously. New services are emerging that generate local traffic among the users in addition to the data traffic between the users and the network. Such device-to-device (D2D) traffic is effectively served by direct transmissions. The thesis demonstrates the possibilities for allowing such direct D2D transmissions on a shared band together with the cellular communication. It is shown that interference management is needed in order to facilitate reliable and efficient shared band operation. For this purpose, three methods are proposed that provide interference aware power control, interference aware multiuser and multiband resource allocation, and interference avoiding spatial precoding. It is shown that enabling direct transmission itself provides most of the gains in system capacity, while the interference management schemes are more important in promoting fairness and reliability.Langattomien tietoliikenneverkkojen käyttö kasvaa erittäin nopeasti mobiilien internet-palvelujen ja älykkäiden päätelaitteiden suosion myötä. Järjestelmien tiedonsiirtokapasiteettiä voidaan lisätä kasvattamalla kaistanleveyttä, spektritehokkuutta ja tukiasemaverkon tiheyttä. Kehityksen mahdollistaa mm. joustava taajuuksien käyttö ja moniantenni- ja monikantoaaltotekniikat. Lisäksi radioverkkojen suunnitteluun, optimointiin, ylläpitoon ja interferenssinhallintaan liittyvien tehtävien automatisoinnilla voidaan pienentää verkko-operaattoreiden kustannuksia. Tässä hetkellisen ja paikallisen tietoliikenteen tehokas, dynaaminen ja automatisoitu interferenssinhallinta on keskeisessä asemassa. Viereisen kanavan interferenssin hallinta mahdollistaa osaltaan joustavan spektrinkäytön ja koordinoimattoman verkkojen asennuksen. Väitöskirjassa on analysoitu viereisen kanavan interferenssin vaikutusta aikajakoiseen dupleksilähetykseen perustuvien paikallisten radioverkkojen toimintaan. Lisäksi väitöskirjassa on kehitetty menetelmä, jolla voidaan hallita interferenssiä reaaliaikaisesti. Menetelmä maksimoi lähetetyn signaalin spektritehokkuuden siten, että tehovahvistimen epälineaarisuuden aiheuttama viereisen kanavan interferenssi on rajoitettu. Väitöskirjassa on kehitetty ja analysoitu uudenlainen interferenssitietoinen lähetysten ajoitustekniikka. Tekniikka hallitsee reaaliaikaisesti ja hajautetusti saman kanavan interferenssiä vastaanottimien lähettämien majakkasignaalien avulla. Esitetyt simulaatiot osoittavat, että tämä mahdollistaa operaattoreiden välisen taajuuskaistojen jaon, ja alas- ja yloslinkkien aikajaon joustavan säädön. Tämän lisäksi on mahdollista saavuttaa korkeampi yleinen spektritehokkuus. Erityisesti tiedonsiirtonopeus solujen reunoille kasvaa esitetyn tekniikan avulla huomattavasti. Uudenlaiset tietoliikennepalvelut lisäävät laitteidenvälisen paikallisen tietoliikenteen määrää. Spektrinkäytön kannalta tämä liikenne on tehokkainta lähettää suoraan laitteesta toiseen. Väitöskirjassa on tutkittu joustavaa spektrinkäyttöä suorien laitteidenvälisten lähetysten ja soluverkon välillä. Interferenssin hallinta takaa luotettavan ja tehokkaan spektrin yhteiskäytön. Tätä varten väitöskirjassa on kehitetty kolme menetelmää, jotka perustuvat tehonsäätöön, lähetysten ajoitukseen ja moniantennilähetykseen

Acesso rádio UMTS, WLAN e WIMAX sobre fibra

Mestrado em Engenharia Electrónica e TelecomunicaçõesO presente trabalho tem por objectivo o estudo e implementação de uma rede óptica passiva para a transmissão de sinais rádio sobre fibra. Para tal, são estudados e analisados diversos componentes optoelectrónicos que constituem uma rede óptica passiva, tendo em vista a optimização e desenvolvimento da mesma. Por forma a definir os limites, bem como desenvolver conhecimentos sobre os processos que limitam ondas de rádio em fibra, foram realizadas simulações computacionais em redes óptica passivas com transmissão de sinais 3G-UMTS, objectivando estudar possibilidades de acesso múltiplo, bem como os efeitos da alteração de determinadas propriedades dos dispositivos ópticos. Para demonstrar os processos limitativos da propagação, laboratorialmente foram implementadas duas topologias de redes ópticas passivas recorrendo a amplificadores ópticos e lasers de baixo custo, para estudar a transmissão de multi-formatos de sinais rádio sobre fibra. A primeira consiste na transmissão de um canal que consiste na modulação directa de um laser com o sinal rádio que pode ser 3G-UMTS, WLAN ou WiMAX. A segunda inclui, para além do cenário apresentado, um canal extra modulado em amplitude num cenário de multiplexagem no comprimento de onda. ABSTRACT: The present work intends to study and implement a passive optical network for the transmission of radio signals over optical fiber. For this intent, several optoelectronic devices used in passive optical networks were studied and analyzed in order to optimize the developed network. A passive optical network for the transmission of 3G-UMTS signals was simulated and the effect of multiple access and other optical factors were studied and analyzed. In the laboratory were implemented two different topologies for passive optical networks using low cost optical amplifiers and lasers in multi-format multiwavelength radio over fiber signals. The first consider the transmission of a single channel consisting of directly modulating the laser with a radio signal that can be UMTS, WLAN or WiMAX, and the second includes an extra channel with amplitude modulated signals in a wavelength division multiplexing scenario