Multiple-Access Technology of Choice In 3GPP LTE

Third-Generation Partnership Project (3GPP) standardizes an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) as air interface in its release 8 LTE. Orthogonal Frequency Division Multiple Access(OFDMA) and Single Carrier-Frequency Division Multiple Access(SC-FDMA)are key technologies for the air interface of mobile broadband systems.It is evident that mobile broadband access technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with OFDMA based air interface technology. The air interface of E-UTRAN is based on OFDMA in downlink and SC-FDMA in the uplink, making it possible to efficiently utilize bandwidth due to the orthogonally between sub-carriers and by assigning subsets of sub-carriers to individual users which allows for simultaneous data rate transmission from several users and differentiated quality of service for each user. In this paper, wehighlight the technologies behindOFDMA and SC-FDMA and also carry out performance comparison of the two air interface technologies. We brieflydescribe the 3GPP LTE standard, and its implementation using OFDMA and SC-FDMA technology

Kapeankaistan LTE koneiden välisessä satelliittitietoliikenteessä

Recent trends to wireless Machine-to-Machine (M2M) communication and Internet of Things (IoT) has created a new demand for more efficient low-throughput wireless data connections. Beside the traditional wireless standards, focused on high bandwidth data transfer, has emerged a new generation of Low Power Wide Area Networks (LPWAN) which targets for less power demanding low-throughput devices requiring inexpensive data connections. Recently released NB-IoT (Narrowband IoT) specification extends the existing 4G/LTE standard allowing more easily accessible LPWAN cellular connectivity for IoT devices. Narrower bandwidth and lower data rates combined to a simplified air interface make it less resource demanding still benefiting from the widely spread LTE technologies and infrastructure. %% Applications & Why space Applications, such as wide scale sensor or asset tracking networks, can benefit from a global scale network coverage and easily available low-cost user equipment which could be made possible by new narrowband IoT satellite networks. In this thesis, the NB-IoT specification and its applicability for satellite communication is discussed. Primarily, LTE and NB-IoT standards are designed only for terrestrial and their utilization in Earth-to-space communication raises new challenges, such as timing and frequency synchronization requirements when utilizing Orthogonal Frequency Signal Multiplexing (OFDM) techniques. Many of these challenges can be overcome by specification adaptations and other existing techniques making minimal changes to the standard and allowing extension of the terrestrial cellular networks to global satellite access.Viimeaikaiset kehitystrendit koneiden välisessä kommunikaatiossa (Machine to Machine Communication, M2M) ja esineiden Internet (Internet of Things, IoT) -sovelluksissa ovat luoneet perinteisteisten nopean tiedonsiirron langattomien standardien ohelle uuden sukupolven LPWAN (Low Power Wide Area Networks) -tekniikoita, jotka ovat tarkoitettu pienitehoisille tiedonsiirtoa tarvitseville sovelluksille. Viimeaikoina yleistynyt NB-IoT standardi laajentaa 4G/LTE standardia mahdollistaen entistä matalamman virrankulutuksen matkapuhelinyhteydet IoT laitteissa. Kapeampi lähetyskaista ja hitaampi tiedonsiirtonopeus yhdistettynä yksinkertaisempaan ilmarajapintaan mahdollistaa pienemmän resurssivaatimukset saman aikaan hyötyen laajalti levinneistä LTE teknologioista ja olemassa olevasta infrastruktuurista. Useissa sovelluskohteissa, kuten suurissa sensoriverkoissa, voitaisiin hyötyä merkittävästi globaalista kattavuudesta yhdistettynä edullisiin helposti saataviin päätelaitteisiin. Tässä työssä käsitellään NB-IoT standardia ja sen soveltuvuutta satellittitietoliikenteeseen. LTE ja NB-IoT ovat kehitty maanpääliseen tietoliikenteeseen ja niiden hyödyntäminen avaruuden ja maan välisessä kommunikaatiossa aiheuttaa uusia haasteita esimerkiksi aika- ja taajuussynkronisaatiossa ja OFDM (Orthogonal Frequency Signal Multiplexing) -tekniikan hyödyntämisessä. Nämä haasteet voidaan ratkaista soveltamalla spesifikaatiota sekä muilla jo olemassa olevilla tekniikoilla tehden mahdollisimman vähän muutoksia alkuperäiseen standardiin, ja täten sallien maanpäälisten IoT verkkojen laajenemisen avaruuteen

A hybrid-structure offset-QAM filter-bank multi-carrier MIMO system

Offset quadrature amplitude modulation (OQAM) filter-bank multi-carrier (FBMC), has great potential for boosting the spectral efficiency (SE) and energy efficiency (EE) of future communication systems. This is due to its superior spectral localization, CP-less transmission and relaxed synchronization requirements. Our research focuses on three main OQAM/FBMC research problems: the computational complexity reduction taking equalization into consideration, its integration with multiple-input multiple-output (MIMO) and its high peak-to-average power ratio (PAPR). OQAM/FBMC systems are mainly implemented either using frequency spreading (FS) or polyphase network (PPN) techniques. The PPN technique is generally less complex, but when using frequency domain equalization (FDE) to equalize multipath channel effects at the receiver, there is a computational complexity overhead when using PPN. A novel hybrid-structure OQAM/FBMC MIMO space-frequency block coding (SFBC) system is proposed, to achieve the lowest possible overall complexity in conjunction with FDE at the receiver in frequency selective Rayleigh fading channel. The Alamouti SFBC block coding is performed on the complex-orthogonal signal before OQAM processing, which resolves the problems of intrinsic interference when integrating OQAM/FBMC with MIMO. In better multipath channel conditions with a line-of-sight (LOS) path, a zero-forcing (ZF) time domain equalization (TDE) is exploited to further reduce the computational complexity with comparable performance bit-error-rate (BER). On the other hand, to tackle the high PAPR problem of the OQAM/FBMC system in the uplink, a novel single carrier (SC)-OQAM/FBMC MIMO system is proposed. The system uses DFT-spreading applied to the OQAM modulated signal, along with interleaved subcarrier mapping to significantly reduce the PAPR and enhance the BER performance over Rayleigh fading channels, with relatively low additional computational complexity compared to the original complexity of the FBMC system and compared to other FBMC PAPR reduction techniques.The proposed hybrid-structure system has shown significant BER performance in frequency-selective Rayleigh fading channels compared to OFDM, with significantly lower OOB emissions in addition to the enhanced SE due to the absence of CP. In mild multipath fading channels with a LOS component, the PPN OQAM/FBMC MIMO using TDE has a comparable BER performance with significantly less computational complexity. As for the uplink, the SC-OQAM/FBMC MIMO system significantly reduces the PAPR and enhances the BER performance, with relatively low additional computational complexity

物理層に着目した産業用高信頼リアルタイム無線通信に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 森川 博之, 東京大学准教授 中山 雅哉, 東京大学教授 相田 仁, 東京大学准教授 川原 圭博, 東京大学教授 廣瀬 明University of Tokyo(東京大学

5G無線通信における誤り訂正符号化方式の評価に関する研究

早大学位記番号:新8267早稲田大

Implementação de um sistema de comunicações móveis para o Uplink

Mestrado em Engenharia Electrónica e TelecomunicaçõesÉ evidente que actualmente cada vez mais a internet móvel está presente na vida das sociedades. Hoje em dia é relativamente fácil estar ligado à internet sempre que se quiser, independentemente do lugar onde se encontra (conceito: anytime and anywhere). Desta forma existe um número crescente de utilizadores que acedem a serviços e aplicações interactivas a partir dos seus terminais móveis. Há, portanto, uma necessidade de adaptar o mundo das telecomunicações a esta nova realidade, para isso é necessário implementar novas arquitecturas que sejam capazes de fornecer maior largura de banda e reduzir os atrasos das comunicações, maximizando a utilização dos recursos disponíveis do meio/rede e melhorando assim a experiência do utilizador final. O LTE representa uma das tecnologias mais avançadas e de maior relevância para o acesso sem fios em banda larga de redes celulares. OFDM é a tecnologia base que está por traz da técnica de modulação, bem como as tecnologias adjacentes, OFDMA e SC-FDMA, usadas especificamente no LTE para a comunicação de dados descendente (downlink) ou ascendente (uplink), respectivamente. A implementação de múltiplas antenas em ambos os terminais, potenciam ainda mais o aumento da eficiência espectral do meio rádio permitindo atingir grandes taxas de transmissão de dados. Nesta dissertação é feito o estudo, implementação e avaliação do desempenho da camada física (camada 1 do modelo OSI) do LTE, no entanto o foco será a comunicação de dados ascendente e a respectiva técnica de modelação, SC-FDMA. Foi implementada uma plataforma de simulação baseada nas especificações do LTE UL onde foram considerandos diferentes esquemas de antenas. Particularmente para o esquema MIMO, usou-se a técnica de codificação no espaço-frequência proposta por Alamouti. Foram também implementados vários equalizadores. Os resultados provenientes da simulação demonstram tanto a eficiência dos diversos modos de operação em termos da taxa de erro, como o excelente funcionamento de processos de mapeamento e equalização, que visam melhorar a taxa de recepção de dados.It is clear that mobile Internet is present in the life of societies. Nowadays it is relatively easy to be connected to the internet whenever you want, no matter where you are (concept: anytime and anywhere). Thus, there are a growing number of users accessing interactive services and applications from their handsets. Therefore, there is a need to adapt the world of telecommunications to this new reality, for that it is necessary to implement new architectures that are able to provide higher bandwidth and reduce communication delays, maximizing use of available resources in the medium/network and thereby improving end-user experience. LTE represents one of the most advanced architectures and most relevant to wireless broadband cellular networks. OFDM is the technology that is behind the modulation technique and the underlying technologies, OFDMA and SCFDMA, used specifically in LTE for data communication downward (downlink) or upward (uplink), respectively. The implementation of multiple antennas at both ends further potentiate the increase of spectral efficiency allowing to achieve high rates of data transmission. In this dissertation is done the study, implementation and performance evaluation of the physical layer (OSI Layer 1) of the LTE, but the focus will be communication and its upstream data modeling technique, SC-FDMA. We implemented a simulation platform based on LTE UL specifications where were considered different antenna schemes. Particularly for the MIMO scheme, we used the technique of space-frequency coding proposed by Alamouti. We also implemented several equalizers. The results from the simulation demonstrate both the efficiency of different modes of operation in terms of error rate, as the excellent operation of mapping processes and equalization, designed to improve the rate of receiving data

LTE Baseband Algorithms for Uplink

LTE is a next generation mobile system from the 3GPP with a focus on wireless broadband.The aim of LTE is to achieve high data rates in both uplink & downlink, and to achieve high spectral efficiencies.The main focus of the work is to develop baseband algorithms in the uplink in order to achieve uplinksynchronization between the user and the base station and also for the detection of the control data that is transmitted. For the base station to obtain the knowledge of the presence of the user and also about its position, the user has to transmit synchronization signals to the base station, which are transmitted on the Physical Random Access CHannel (PRACH) in LTE. These signals are used to obtain the uplink timing correction and hence synchronize with the base station. It is very important for the base station to detect the control data that has been transmitted by the user on Physical Uplink Control CHannel (PUCCH). The control data may consist of the response of the UE to the data packets that were transmitted by the base station, request for resource allocation etc.So efficient algorithms are necessary for the accurate detection of the control data at the base station. The current work presents algorithms that are essential for obtaining uplink synchronization and also for efficient detection of the control channel data