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
More filters
Patent•
25 May 2017TL;DR: In this article, the first reference signal received from a user equipment (UE) in a reference scheduled transmission burst including a plurality of contiguous transmission time intervals (TTIs) received over a shared radio frequency spectrum band was identified.
Abstract: Techniques are described for wireless communication. One method includes detecting a first reference signal received from a user equipment (UE) in a reference scheduled transmission burst including a plurality of contiguous transmission time intervals (TTIs) received over a shared radio frequency spectrum band; identifying a reference TTI in which the first reference signal is received; determining a contention window size usable by the UE to contend for access to the shared radio frequency spectrum band; and transmitting an indication of the determined contention window size to the UE.
22 citations
TL;DR: A robustified WMMSE algorithm (RB-WMMSE) based on the well-known diagonal loading framework is proposed, and the resulting diagonally loaded spatial filters are shown to perform significantly better than the naïve filters.
Abstract: Several distributed coordinated precoding methods exist in the downlink multicell multiple-input–multiple-output (MIMO) literature, many of which assume perfect knowledge of received signal covariance and local effective channels. In this paper, we let the notion of channel state information (CSI) encompass this knowledge of covariances and effective channels. We analyze what local CSI is required in the weighted minimization of the mean square error (WMMSE) algorithm for distributed coordinated precoding, and we study how this required CSI can be obtained in a distributed fashion. Based on pilot-assisted channel estimation, we propose three CSI acquisition methods with different tradeoffs between feedback and signaling, backhaul use, and computational complexity. One of the proposed methods is fully distributed, meaning that it only depends on over-the-air signaling but requires no backhaul, and it results in a fully distributed joint system when coupled with the WMMSE algorithm. Naively applying the WMMSE algorithm together with the fully distributed CSI acquisition results in catastrophic performance however; therefore, we propose a robustified WMMSE algorithm (RB-WMMSE) based on the well-known diagonal loading framework. By enforcing properties of the WMMSE solutions with perfect CSI onto the problem with imperfect CSI, the resulting diagonally loaded spatial filters are shown to perform significantly better than the naive filters. The proposed robust and distributed system is evaluated using numerical simulations and is shown to perform well compared with benchmarks. Under centralized CSI acquisition, the proposed algorithm performs on par with other existing centralized robust WMMSE algorithms. When evaluated in a large-scale fading environment, the performance of the proposed system is promising.
22 citations
01 Dec 2015
TL;DR: Outdoor field experimental results to clarify the 4x4 MIMO throughput performance from applying multi-point transmission in the 15 GHz frequency band in the downlink of 5G cellular radio access system shows that up to 30 % throughput gain compared to non-multi-point Transmission is achieved although the difference for the RSRP of two TPs is over 10 dB, so that the improvement for the antenna correlation is achievable.
Abstract: This paper presents outdoor field experimental results to clarify the 4x4 MIMO throughput performance from applying multi-point transmission in the 15 GHz frequency band in the downlink of 5G cellular radio access system. The experimental results in large-cell scenario shows that up to 30 % throughput gain compared to non-multi-point transmission is achieved although the difference for the RSRP of two TPs is over 10 dB, so that the improvement for the antenna correlation is achievable and important aspect for the multi-point transmission in the 15 GHz frequency band as well as the improvement of the RSRP. Furthermore in small-cell scenario, the throughput gain of 70% and over 5 Gbps are achieved applying multi-point transmission in the condition of two different MIMO streams transmission from a single TP as distributed MIMO instead of four MIMO streams transmission from a single TP.
22 citations
16 Jun 2013
TL;DR: By combining multi-group multicast beamforming with Alamouti space-time block coding, the degrees of freedom in the beamformer design is doubled resulting in drastically improved beamforming performance.
Abstract: This paper addresses adaptive beamforming in multi-group multicasting networks where groups of users subscribe to independent services that are simultaneously served by the base station. Beamformers are designed to maximize the minimum signal-to-interference-plus-noise ratio (SINR) of the users in all groups subject to a total transmit power constraint. By combining multi-group multicast beamforming with Alamouti space-time block coding, the degrees of freedom in the beamformer design is doubled resulting in drastically improved beamforming performance. In our paper we extend recent approaches in [1] and [2] for rank-two beamforming, originally devised for single-group multicasting networks that are free of multi-user interference, to multi-group multicasting networks, where multi-user interference represents a major challenge. Simulation results demonstrate that the proposed approach significantly outperforms the existing approaches.
22 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...In order to fulfill the growing demand for data rates and spectral efficiency in future wireless multimedia broadcast and multicast services [3], transmit beamforming techniques have been extensively studied in recent years [4], [5]....
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TL;DR: This paper combines beamforming with full-rate high dimensional real-valued orthogonal space time block coding (OSTBC) to increase the number of beamforming weight vectors and associated degrees of freedom in the beamformer design.
Abstract: In this paper, we consider optimal multiuser downlink beamforming in the presence of a massive number of arbitrary quadratic shaping constraints We combine beamforming with full-rate high dimensional real-valued orthogonal space time block coding (OSTBC) to increase the number of beamforming weight vectors and associated degrees of freedom in the beamformer design The original multi-constraint beamforming problem is converted into a convex optimization problem using semidefinite relaxation (SDR) which can be solved efficiently In contrast to conventional (rank-one) beamforming approaches in which an optimal beamforming solution can be obtained only when the SDR solution (after rank reduction) exhibits the rank-one property, in our approach optimality is guaranteed when a rank of eight is not exceeded We show that our approach can incorporate up to 79 additional shaping constraints for which an optimal beamforming solution is guaranteed as compared to a maximum of two additional constraints that bound the conventional rank-one downlink beamforming designs Simulation results demonstrate the flexibility of our proposed beamformer design
22 citations