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
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01 Jul 2013
TL;DR: This work proposes a new scheduling framework, which extends conventional short-term scheduling with long-term QoS information from previously traversed cells and demonstrates the scheme for relevant channel-aware as well as for channel and queue-aware schedulers.
Abstract: In current cellular networks, schedulers allocate wireless channel resources to users based on short-term moving averages of the channel gain and of the queuing state. Using only such short-term information, schedulers ignore the user's service history in previous cells and, thus, cannot meet long-term Quality of Service (QoS) guarantees when users traverse cells with varying load and capacity. We propose a new scheduling framework, which extends conventional short-term scheduling with long-term QoS information from previously traversed cells. We demonstrate our scheme for relevant channel-aware as well as for channel and queue-aware schedulers. Our simulation results show high gains in long-term QoS while the average throughput of the network increases. Therefore, the proposed scheduling approach improves subscriber satisfaction while increasing operational efficiency.
6 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...In this section we present a scheduling framework that improves the long-term user QoS over multiple cells, without compromising short-term application needs....
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Posted Content•
TL;DR: In this article, the main results obtained from the research carried out in the work package 2 (WP2) of the Roll2Rail (R2R) project are presented. And the goal for WP2 is to research on both technologies and architectures to develop a new wireless Train Communication Network (TCN) within IEC61375 standard series.
Abstract: This paper explains the main results obtained from the research carried out in the work package 2 (WP2) of the Roll2Rail (R2R) project. This project aims to develop key technologies and to remove already identified blocking points for radical innovation in the field of railway vehicles, to increase their operational reliability and to reduce life-cycle costs. This project started in May 2015 and has been funded by the Horizon 2020 program of the European Commission. The goal for WP2 is to research on both technologies and architectures to develop a new wireless Train Communication Network (TCN) within IEC61375 standard series. This TCN is today entirely wired and is used for Train Control and Monitoring System (TCMS) functions (some of them safetyrelated), operator-oriented services and customer-oriented services. This paradigm shift from wired to wireless means a removal of wirings implies, among other benefits, a significant reduction of life cycle costs due to the removal of cables, and the simplification of the train coupling procedure, among others.
6 citations
Posted Content•
TL;DR: In this paper, the uplink transmission from a UAV to cellular BSs, under spectrum sharing with the existing ground users, was investigated to maximize the weighted sum-rate of the UAV and existing ground-users by jointly optimizing the UV's uplink cell associations and power allocations over multiple resource blocks.
Abstract: The line-of-sight (LoS) air-to-ground channel brings both opportunities and challenges in cellular-connected unmanned aerial vehicle (UAV) communications. On one hand, the LoS channels make more cellular base stations (BSs) visible to a UAV as compared to the ground users, which leads to a higher macro-diversity gain for UAV-BS communications. On the other hand, they also render the UAV to impose/suffer more severe uplink/downlink interference to/from the BSs, thus requiring more sophisticated inter-cell interference coordination (ICIC) techniques with more BSs involved. In this paper, we consider the uplink transmission from a UAV to cellular BSs, under spectrum sharing with the existing ground users. To investigate the optimal ICIC design and air-ground performance trade-off, we maximize the weighted sum-rate of the UAV and existing ground users by jointly optimizing the UAV's uplink cell associations and power allocations over multiple resource blocks. However, this problem is non-convex and difficult to be solved optimally. We first propose a centralized ICIC design to obtain a locally optimal solution based on the successive convex approximation (SCA) method. As the centralized ICIC requires global information of the network and substantial information exchange among an excessively large number of BSs, we further propose a decentralized ICIC scheme of significantly lower complexity and signaling overhead for implementation, by dividing the cellular BSs into small-size clusters and exploiting the LoS macro-diversity for exchanging information between the UAV and cluster-head BSs only. Numerical results show that the proposed centralized and decentralized ICIC schemes both achieve a near-optimal performance, and draw important design insights based on practical system setups.
6 citations
TL;DR: In this paper, a new variant of selective spanning fast enumeration (SSFE) is proposed, which employs novel fast symbol enumeration and modulation dictionary spanning heuristics to increase performance and computational efficiency to the point where very substantial reductions in resource can be achieved without impacting detection accuracy.
Abstract: Sphere decoders allow receivers in multiple-input multiple-output (MIMO) communications systems to detect QAM symbols with quasi-optimal accuracy and low complexity compared with the ideal maximum likelihood detector. However, their high complexity relative to simple linear detectors means that the latter are still usually adopted, despite their lower detection performance. Configurable sphere decoders, such as selective spanning fast enumeration (SSFE), allow complexity to be reduced at the cost of lower performance and are hence ideal for transceivers for Internet-of-Things equipment, where scale, operating context and resource, and energy budgets vary dramatically. However, SSFE still suffers performance limitations due to the internal heuristics employed for symbol selection and enumeration and real time, and software-defined realizations for even moderately demanding MIMO standards, such as 802.11n, have not been recorded. This paper presents a new variant of SSFE which, by employing novel fast symbol enumeration and modulation dictionary spanning heuristics, increases performance and computational efficiency to the point where very substantial reductions in resource can be achieved without impacting detection accuracy relative to SSFE. This is demonstrated via a series of field programmable gate array-based detectors $2 \times 2$ and $4 \times 4$ , 16-QAM 802.11n MIMO.
6 citations
TL;DR: Two levels of complexity reduction in the process of estimating the channel information in cellular networks are presented, demonstrating that complexity can be minimized from O(N3) to O((N/k)3), by dividing the processing of RRHs into parallel groups and harnessing the MapReduce parallel algorithm in order to process them.
Abstract: Cloud computing is considered as one of the key drivers for the next generation of mobile networks (e.g., 5G). This is combined with the dramatic expansion in mobile networks, involving millions (or even billions) of subscribers with a greater number of current and future mobile applications (e.g., IoT). Cloud Radio Access Network (C-RAN) architecture has been proposed as a novel concept to gain the benefits of cloud computing as an efficient computing resource, to meet the requirements of future cellular networks. However, the computational complexity of obtaining the channel state information in the full-centralized C-RAN increases as the size of the network is scaled up, as a result of enlargement in channel information matrices. To tackle this problem of complexity and latency, MapReduce framework and fast matrix algorithms are proposed. This paper presents two levels of complexity reduction in the process of estimating the channel information in cellular networks. The results illustrate that complexity can be minimized from O(N3) to O((N/k)3), where N is the total number of RRHs and k is the number of RRHs per group, by dividing the processing of RRHs into parallel groups and harnessing the MapReduce parallel algorithm in order to process them. The second approach reduces the computation complexity from O((N/k)3) to O((N/k)2.807) using the algorithms of fast matrix inversion. The reduction in complexity and latency leads to a significant improvement in both the estimation time and in the scalability of C-RAN networks.
6 citations