Massive MIMO systems are a key technology for next generation cellular networks. Albeit their numerous advantages, they present a dimensionality challenge when the number of users and the number of antenna ports increases, especially when the number of antennas grows increasingly large. In this paper, we propose a novel flexible codebook design framework that leverages the approximation of the covariance matrix with a Kronecker product model of three domain components: azimuth, vertical and uncorrelated dimensions. We derive the component matrices of the Kronecker product model, and we present simulation results to corroborate this approximation. The analysis in this paper lays the theoretical foundation for usage of a product codebook to reduce the complexity and the dimensionality of feedback in massive MIMO systems.
Abstract Purpose To determine whether the ocular phenotype in patients with mucopolysaccharidosis type I (MPSI) Hurler is affected by the efficacy of previous haemopoietic stem cell transplantation (HSCT). Design A retrospective cohort study of patients with MPSI who had undergone treatment with HSCT. Methods Ocular phenotype was documented for each patient and compared to levels of biomarkers representing efficacy of previous transplantation. Main outcome measures: Assessment of visual acuity (VA), severity of corneal clouding and the presence of optic neuropathy or retinopathy. Biomarker assessment included dermatan sulphate/chondroitin sulphate (DS/CS) ratio and iduronidase enzyme level. Results Severe corneal clouding was significantly greater in patients with lower iduronidase levels (p = 0.023) and raised DS/CS ratio ( R 2 = 0.28 p = 0.043). Better VA was related to a higher iduronidase levels ( R 2 = 0.15, p = 0.004) and lower DS/CS ratio ( R 2 = 0.38, p = 0.001). Conclusion Improved ocular phenotypes in MPSI are associated with markers signifying efficacy of prior transplant. Early and effective HSCT may result in a better visual prognosis and reduction in ocular complications for patients with MPSI.
is the eBook version of the printed book. Praise for of WiMAX This book is one of the most comprehensive books I have reviewed ... it is a must-read for engineers and students planning to remain current or who plan to pursue a career in telecommunications. I have reviewed other publications on WiMAX and have been disappointed. book is refreshing in that it is clear that the authors have the in-depth technical knowledge and communications skills to deliver a logically laid out publication that has substance to it. Ron Resnick, President, WiMAX Forum This is the first book with a great introductory treatment of WiMAX technology. It should be essential reading for all engineers involved in WiMAX. The high-level overview is very useful for those with non-technical background. The introductory sections for OFDM and MIMO technologies are very useful for those with implementation background and some knowledge of communication The chapters covering physical and MAC layers are at the appropriate level of detail. In short, I recommend this book to systems engineers and designers at different layers of the protocol, deployment engineers, and even students who are interested in practical applications of communication theory. Siavash M. Alamouti, Chief Technology Officer, Mobility Group, Intel This is a very well-written, easy-to-follow, and comprehensive treatment of WiMAX. It should be of great interest. Dr. Reinaldo Valenzuela, Director of Wireless Research, Bell Labs Fundamentals of WiMAX is a comprehensive guide to WiMAX from both industry and academic viewpoints, which is an unusual accomplishment. I recommend it to anyone who is curious about this exciting new Dr. Teresa Meng, Professor, Stanford University, Founder and Director, Atheros Communications Andrews, Ghosh, and Muhamed have provided a clear, concise, and well-written text on 802.16e/WiMAX. The book provides both the breadth and depth to make sense of the highly complicated 802.16e standard. I would recommend this book to both development engineers and technical managers who want an understating of WiMAX and insight into 4G modems in general. Paul Struhsaker, VP of Engineering, Chipset platforms, Motorola Mobile Device Business Unit, former vice chair of IEEE 802.16 working group Fundamentals of WiMAX is written in an easy-to-understand tutorial fashion. The chapter on multiple antenna techniques is a very clear summary of this important technology and nicely organizes the vast number of different proposed techniques into a simple-to-understand framework. Dr. Ender Ayanoglu, Professor, University of California, Irvine, Editor-in-Chief, IEEE Transactions on Communications Fundamentals of WiMAX is a comprehensive examination of the 802.16/WiMAX standard and discusses how to design, develop, and deploy equipment for this wireless communication standard. It provides both insightful overviews for those wanting to know what WiMAX is about and comprehensive, in-depth chapters on technical details of the standard, including the coding and modulation, signal processing methods, Multiple-Input Multiple-Output (MIMO) channels, medium access control, mobility issues, link-layer performance, and system-level performance. Dr. Mark C. Reed, Principal Researcher, National ICT Australia, Adjunct Associate Professor, Australian National University This book is an excellent resourc...
Since the UK commenced newborn screening for isovaleric acidemia in 2015, changes in prescribing have increased the incidence of false positive (FP) results due to pivaloylcarnitine. A review of screening results between 2015-22 identified 24 true positive (TP) and 84 FP cases, with pivalate interference confirmed in 76/84. Initial C5 carnitine (C5C) did not discriminate between FP and TP with median (range) C5C of 2.9 (2.0 - 9.6) and 4.0 (1.8 - >70) µmol/L respectively and neither did Precision Newborn Screening via Collaborative Laboratory Integrated Reports (CLIR), which identified only 1/47 FP cases. However, among the TP cases, disease severity showed a correlation with initial C5C, in ‘asymptomatic’ individuals (n=17), demonstrating a median (range) C5C of 3.0 (1.8 – 7.1) whilst ‘clinically affected’ patients (n=7), showed a median (range) C5C of 13.9 (7.7 - > 70) µmol/L. These findings allowed the introduction of dual cut-off values into the screening algorithm to reduce the incidence of FPs, with initial C5C results ≥ 5 µmol/L triggering urgent referral, and those > 2.0 and < 5.0 µmol/L prompting 2nd tier C5-isobar testing. This will avoid delayed referral in babies at particular risk whilst reducing the FP rate for the remainder.
We compare the performance of heterogeneous networks (HetNets) with self backhauled small cells (SBSCs) relative to those with wired backhaul based small cells (WBSCs). The comparisons are made for a variety of SBSC based HetNets including: 1) when the HetNets employ omni antennas at the SBSCs and Uniform PF at the macro; 2) with directional antennas at the SBSCs and uniform PF at the macro; 3) with directional antennas at the SBSCs and weighted PF at the macro; and 4) with Directional antennas at the SBSCs and QoS-aware PF at the macro. The study catalogs our learning experiences with SBSC HetNets, leading the reader through the sequence of enhancements made to improve the performance of SBSC HetNets relative to WBSC HetNets.
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