Book•
4G: LTE/LTE-Advanced for Mobile Broadband
21 Mar 2011-
TL;DR: In this article, the authors focus on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system, including the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance.
Abstract: Based on the bestseller "3G Evolution - HSPA and LTE for mobile broadband" and reflecting the ongoing success of LTE throughout the world, this book focuses on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system. Overview and detailed explanations are given for the latest LTE standards for radio interface architecture, the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, advanced radio resource management and protocols, and different radio network architectures. Their role and use in the context of mobile broadband access in general is explained. Both a high-level overview and more detailed step-by-step explanations of the LTE/LTE-Advanced implementation are given. An overview of other related systems such as GSM/EDGE, HSPA, CDMA2000, and WIMAX is also provided. This book is a 'must-have' resource for engineers and other professionals in the telecommunications industry, working with cellular or wireless broadband technologies, giving an understanding of how to utilize the new technology in order to stay ahead of the competition. The authors of the book all work at Ericsson Research and have been deeply involved in 3G and 4G development and standardisation since the early days of 3G research. They are leading experts in the field and are today still actively contributing to the standardisation of LTE within 3GPP. Includes full details of the latest additions to the LTE Radio Access standards and technologies up to and including 3GPP Release 10Clear explanations of the role of the underlying technologies for LTE, including OFDM and MIMO Full coverage of LTE-Advanced, including LTE carrier aggregation, extended multi-antenna transmission, relaying functionality and heterogeneous deploymentsLTE radio interface architecture, physical layer, access procedures, MBMS, RF characteristics and system performance covered in detail
Citations
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01 Jan 2013
TL;DR: Two different approaches, namely, quantized CSI feedback and automatic repeat request (ARQ) are considered, providing the imperfect channel quality information at the transmitter, to increase the transmission reliability in the absence of the transmitter CSI.
Abstract: Foreword Modern wireless systems include key technologies such as multiuser diversity, adaptive transmission, multiple-input multiple-output (MIMO) processing and cooperative data communication networks. Common for all these technologies is that the feedback of channel state information (CSI) is necessary, as it is exploited for adapting the transmission parameters, scheduling, etc. The CSI is normally obtained by direct estimation of the channel coefficients at the receiver and somehow informing the transmitter about the obtained complex fading coefficients. The more information available at the transmitter, the better performance can be achieved. However, depending on the channel characteristics, number of transmit/receive antennas, etc., the rate of the feedback information may be so high that it will consume much of the capacity in the reverse link, making the whole system impractical. Therefore, it has often been questioned whether the improved system performance due to CSI feedback is worth the additional feedback rate and the increased implementation complexity. Thus, different CSI feedback compression techniques have been of interest during the last two decades. In the thesis, we consider two different approaches, namely, quantized CSI feedback and automatic repeat request (ARQ), providing the imperfect channel quality information at the transmitter. Implementing a quantized CSI feedback scheme, the receiver provides the transmitter with some rough measure of the channel gain before transmission, and the transmitter adjusts its transmission parameters according to this imperfect information. Rough CSI is normally produced by channel gain quantization at the receiver where the set of all possible channel gains is partitioned into a number of non-overlapping regions. The instantaneous channel gain being in a region, its representing symbol is sent back and the transmitter selects the codewords transmission parameters such that the system performance is optimized. The ARQ, on the other hand, is a well-known approach applied in today's networks to increase the transmission reliability in the absence of the transmitter CSI. From an information-theoretic point of view, the ARQ systems can be viewed as channels with sequential feedback where the transmitter CSI is refined in the retransmissions based on the message decoding status. In a general ARQ approach, the transmitter considers some initial transmission rate and power with no pre-knowledge about the channel quality. Then, with the help of ARQ, the decoding status at the receiver will be reported back to the transmitter via one bit feedback. Based on the received feedback, it is decided by the transmitter whether to retransmit the …
3 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...The relay networks have been adopted in the long-term evolution advanced (LTE-A) standardization [188] and are expected to be one of the core technologies for the next generation cellular systems....
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Patent•
10 Apr 2020
TL;DR: In this article, a 3D-antenna array consisting of a plurality of antenna elements, each antenna element having a radiation pattern, wherein the radiation patterns overlap with respect to each other, is adapted for a coherent wireless communication in a wireless communication system.
Abstract: A transmitter comprises a 3-dimensional antenna array comprising a plurality of antenna elements, each antenna element having a radiation pattern, wherein the radiation patterns overlap with respect to each other The plurality of antenna elements is adapted for a coherent wireless communication in a wireless communication system The 3D-antenna array comprises a first and a second and a third antenna element spanning a 2- dimensional antenna plane, and comprising a fourth antenna element being arranged outside the 2-dimensional antenna plane; or the 3D-antenna array comprises a first antenna element being configured to direct a transmitted signal into a first direction, and comprising a second antenna element being configured to direct a transmitted signal into a second direction and not into the first direction The transmitter further comprises a precoder connected through the 3D-antenna array, to form one or more transmit beams and/or receive beams with the 3D-antenna array The beams point in directions of interest The precoder comprises a precoder matrix that is based on a beam-set matrix and a selection matrix and a power allocation matrix comprising power values that indicate a power to be allocated to the antenna elements of the 3D-antenna array The power allocation matrix is adapted to selectively adjust the transmit power of individual antenna elements
3 citations
Dissertation•
22 Jul 2012
TL;DR: Ein neues Multicast-Verfahren zur naherungsweisen Minimierung der Sendeleistung unter Nebenbedingungen fur die Signal-zu-Rauschverhaltnisse an den Empfangern werden.
Abstract: Zahlreiche Anwendungen wie mobiles Fernsehen und Podcasts erfordern die parallele Verbereitung von Daten an mehrere Nutzer. Drahtlose Multicast-Verfahren ermoglichen dies in einer effizienten Weise, indem die fur eine Gruppe von Nutzern bestimmten Daten und Services diesen simultan zugestellt werden. Aus diesem Grund spielen drahtlose Multicast-Verfahren eine wichtige Rolle fur zukunftige zellulare Mobilfunksysteme. In modernen Mobilfunksystemen werden Mehrantennensysteme eingesetzt, um eine hohe spektrale Effizienz zu erreichen. Im Fall von Mehrantennensystemen konnen Beamformingverfahren verwendet werden, um unterschiedlicher Nachrichten gleichzeitig jedoch raumlich unterschiedlich abgestrahlt werden.
In dieser Arbeit entwickeln wir recheneffiziente Beamformingalgorithmen fur Multicast-Systeme. Die vorgeschlagenen Algorithmen erreichen einen verbesserten Kompromiss zwischen Sendeleistung und Rechenkomplexitat im Vergleich mit existierenden Verfahren.
Zuerst untersuchen wir Single-Group Multicast-Systeme, in denen alle Nutzer dieselben Daten empfangen. Wir entwickeln ein neues Verfahren zur naherungsweisen Minimierung der Sendeleistung unter Nebenbedingungen fur die Signal-zu-Rauschverhaltnisse an den Empfangern. Das vorgeschlagene Verfahren beruht auf der Orthogonalisierung
der Kanalsignaturen einzelner Nutzer. Es erreicht einen verbesserten Kompromiss zwischen Sendeleistung und Rechenkomplexitat im Vergleich mit existierenden
Algorithmen fur Single-Group Multicast-Systeme.
Als nachstes betrachten wir Multi-Group Multicast-Systeme, bei denen unterschiedliche Daten an mehrere Gruppen von Nutzern gesendet werden. Wir schlagen ein neues Multicast-Verfahren vor, bei dem eine geringe Sendeleistung mittels einer hierarchischen Modulation erreicht wird. Das vorgeschlagene Verfahren hat einen geringeren Rechenaufwand und fuhrt zu einer niedrigeren Sendeleistung im Vergleich
zu existierenden Verfahren.
Danach erweitern wir das fur Mehrantennensysteme vorgeschlagene Kanal-Orthogonalisierungsverfahren auf nicht triviale Weise fur den Einsatz in kooperative Relaynetze.
Auch in dieser Anwendung lsst sich mit dem vorgeschlagenen Verfahren eine geringe Rechenkomplexitat und eine niedrigere Sendeleistung als die bekannten Verfahren fur kooperative Relaynetze erzielen.
Schlieslich entwickeln wir verteiltes Beamformingverfahren fur nicht synchronisierte kooperativen Relaynetzen. Wir verwenden ein orthogonale Frequenzmultiplexverfahren,
um die Intersymbolinterferenz am Empfanger zu vermeiden, ohne Verzogerungsglieder an den Relays zu benotigen. Dadurch wird der fur vollstandig synchronisierte Relaynetze ansonsten erforderliche Signalisierungsoverhead vermieden. Wir vergleichen dann die erforderliche Sendeleistungen fur das vorgeschlagene Verfahren mit der
Sendeleistung fur ein vollstandig synchronisiertes Relaynetzwerk.
3 citations
TL;DR: This contribution proposes a novel hybrid prefix (HP) structure, which can offer higher spectral efficiency for orthogonal frequency division multiplexing (OFDM) based future wireless communications, such as 5G and beyond systems.
Abstract: Prefix-based multicarrier transmission is in wide application in current wireless communications, at the expense of extra redundancy and reduced spectral efficiency. In this contribution, we propose a novel hybrid prefix (HP) structure, which can offer higher spectral efficiency for orthogonal frequency division multiplexing (OFDM) based future wireless communications, such as 5G and beyond systems. Compared with the conventional prefix aided OFDM scheme, the proposed HP-OFDM scheme is capable of reducing the average length of the prefix with the aid of a proposed low-complexity detector for efficient signal restoration. We also quantify the signal to interference plus noise and the achievable rate of the proposed HP-OFDM scheme through a theoretical analysis. Furthermore, the bit-error rate (BER) of the proposed HP-OFDM is also theoretically derived. Our scheme results demonstrate that HP-OFDM is capable of reducing the prefix overhead by 50% compared with prefix-aided OFDM, while achieving a BER comparable to that of prefix-aided OFDM.
3 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...Most importantly, prefix-aided OFDM and other correlative multicarrier techniques have been adopted in the long-term evolution (LTE) system such as 4G [5], where prefix-aided OFDM and single carrier frequency division multiple access (SC-FDMA) [6] are chosen for downlink and uplink transmission, respectively....
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01 Nov 2019
TL;DR: A simulation result of NB-IoT’s random access procedure under massive number of devices in steady-state condition shows that a probability of transmitting packet also has a role in performance, where the higher of probability to generate uplink packet, the higher the lost packet will occur.
Abstract: Next generation wireless communication technology of Internet of Things (IoT) nowadays is already used in many use cases. In 2016 3GPP) started introducing a new technology called Narrowband Internet of Things (NB-IoT). Targeting to serve the market of IoT devices, NB-IoT is designed to be better in dealing with large number of subscriber equipments or IoT devices in a cell, compared to the existing cellular technologies. The biggest challenge to serve large number of connecting devices in wireless technologies is the random access, which serves as an entrance gate for the devices demanding physical resources for data transmission. This paper presents a simulation result of NB-IoT‘s random access procedure under massive number of devices in steady-state condition. A backoff mechanism with retry limit is considered with one coverage enhancement level. The result shows that a probability of transmitting packet also has a role in performance, where the higher of probability to generate uplink packet, the higher the lost packet will occur.
3 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...NPRACH refers to the time frequency resource on which random access preambles are transmitted [5]....
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