223 research outputs found
Low complexity scalable MIMO sphere detection through antenna detection reordering
This paper describes a novel low complexity scalable multiple-input multiple-output (MIMO) detector that does not require preprocessing and the optimal squared l2-norm computations to achieve good bit error (BER)
performance. Unlike existing detectors such as Flexsphere that use preprocessing before MIMO detection to improve performance, the proposed detector instead performs multiple search passes, where each search pass detects the transmit stream with a different permuted detection order.
In addition, to reduce the number of multipliers required in
the design, we use l1-norm in place of the optimal squared
l2-norm. To ameliorate the BER performance loss due to l1-
norm, we propose squaring then scaling the l1-norm. By changing the number of parallel search passes and using norm scaling, we show that this design achieves comparable performance to Flexsphere with reduced resource
requirement or achieves BER performance close to exhaustive search with increased resource requirement.National Science Foundatio
Implementation of a High Throughput Soft MIMO Detector on GPU
Multiple-input multiple-output (MIMO) significantly increases the throughput of a communication system by employing multiple antennas at the transmitter
and the receiver. To extract maximum performance from a MIMO system, a computationally intensive search based detector is needed. To meet the challenge
of MIMO detection, typical suboptimal MIMO detectors are ASIC or FPGA designs. We aim to show that a MIMO detector on Graphic processor unit (GPU),
a low-cost parallel programmable co-processor, can achieve high throughput and can serve as an alternative to ASIC/FPGA designs. However, careful architecture
aware software design is needed to leverage the performance offered by GPU. We propose a novel soft MIMO detection algorithm, multi-pass trellis traversal
(MTT), and show that we can achieve ASIC/FPGA-like performance and handle different configurations in software on GPU. The proposed design can be used
to accelerate wireless physical layer simulations and to offload MIMO detection processing in wireless testbed platforms.NokiaNokia Siemens Networks (NSN)Texas InstrumentsXilinxNational Science Foundatio
Linear and Dirty-Paper Techniques for the Multiuser MIMO Downlink
Multi-input, multi-output (MIMO) communications systems have attracted considerable attention over the past decade, mostly for single-user, point-to-point scenarios. The multiple-user MIMO case has attracted less attention, and most of the research on this problem has focused on uplink communications. Only recently has the multi-user MIMO downlink been addressed, beginning with information-theoretic capacity results [1–5], and followed by prac-tical implementations, including those based on linear techniques [6, 7] and non-linear pre-coding [8–11]. In this chapter we review these techniques and discuss some important open problems
A High Throughput Configurable SDR Detector for Multi-user MIMO Wireless Systems
Spatial division multiplexing (SDM) in
MIMO technology significantly increases the spectral
efficiency, and hence capacity, of a wireless communication
system: it is a core component of the next generation
wireless systems, e.g. WiMAX, 3GPP LTE and
other OFDM-based communication schemes. Moreover,
spatial division multiple access (SDMA) is one
of the widely used techniques for sharing the wireless
medium between different mobile devices. Sphere detection
is a prominent method of simplifying the detection
complexity in both SDM and SDMA systems
while maintaining BER performance comparable with
the optimum maximum-likelihood (ML) detection. On
the other hand, with different standards supporting
different system parameters, it is crucial for both base
station and handset devices to be configurable and
seamlessly switch between different modes without the
need for separate dedicated hardware units. This challenge
emphasizes the need for SDR designs that target
the handset devices. In this paper, we propose the
architecture and FPGA realization of a configurable
sort-free sphere detector, Flex-Sphere, that supports
4, 16, 64-QAM modulations as well as a combination of 2, 3 and 4 antenna/user configuration for handsets.
The detector provides a data rate of up to 857.1 Mbps
that fits well within the requirements of any of the next
generation wireless standards. The algorithmic optimizations
employed to produce an FPGA friendly realization
are discussed.Xilinx Inc.National Science Foundatio
Reporting guidelines for surgical technique could be improved: a scoping review and a call for action.
To identify reporting guidelines related to surgical technique and propose recommendations for areas that require improvement.
A protocol-guided scoping review was conducted. A literature search of MEDLINE, the EQUATOR Network Library, Google Scholar, and Networked Digital Library of Theses and Dissertations was conducted to identify surgical technique reporting guidelines published up to December 31, 2021.
We finally included 55 surgical technique reporting guidelines, vascular surgery (n = 18, 32.7%) was the most common among the clinical specialties covered. The included guidelines generally showed a low degree of international and multidisciplinary cooperation. Few guidelines provided a detailed development process (n = 14, 25.5%), conducted a systematic literature review (n = 13, 23.6%), used the Delphi method (n = 4, 7.3%), or described post-publication strategy (n = 6, 10.9%). The vast majority guidelines focused on the reporting of intraoperative period (n = 50, 90.9%). However, of the guidelines requiring detailed descriptions of surgical technique methodology (n = 43, 78.2%), most failed to provide guidance on what constitutes an adequate description.
Our study demonstrates significant deficiencies in the development methodology and practicality of reporting guidelines for surgical technique. A standardized reporting guideline that is developed rigorously and focuses on details of surgical technique may serve as a necessary impetus for change
The prognostic role of WHO classification, urinary 5-hydroxyindoleacetic acid and liver function tests in metastatic neuroendocrine carcinomas of the gastroenteropancreatic tract
The World Health Organisation (WHO) classification (2000) is widely used to classify neuroendocrine carcinomas (NECs), yet its prognostic value needs to be confirmed. In this study, patients with metastatic NECs (n=119) were classified according to WHO guidelines into well differentiated and poorly differentiated (WDNECs and PDNECs). Histological differentiation based on WHO criteria had the highest impact on overall survival (OS) (PDNECs : WDNECs hazard ratio (HR)=4.02, P=0.02); however, PDNECs represented only a small percentage of patients (8%). In a WDNEC-restricted analysis, abnormal liver function tests (LFTs) and elevated urinary 5-hydroxyindoleacetic acid (u5HIAA) were independent prognostic factors for survival (HR=2.65, P=0.006 and HR=2.51, P=0.003, respectively) and were used to create a WDNEC-specific prognostic model (low risk=both normal, intermediate risk=one of them abnormal, high risk=both abnormal). Low-risk WDNECs had the most favourable prognosis (median OS, mOS 8.1 years), which was significantly better compared to both intermediate-risk and high-risk WDNECs (mOS 3.2 and 1.4 years, with P=0.01 and P<0.001, respectively). High-risk WDNECs displayed the shortest OS (1.3 years), which was similar to that of PDNECs (P=0.572). This analysis supports the prognostic value of WHO classification for metastatic NECs arising from the gastroenteropancreatic tract; however, risk stratification using readily available u5HIAA and LFTs may be necessary for the heterogeneous group of WDNECs
Vitamin C and infectious diseases
Non peer reviewe
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