Large-scale (or massive) multiple-input multiple-out put (MIMO) is expected to be one of the key technologies in next-generation multi-user cellular systems based on the upcoming 3GPP LTE Release 12 ...standard, for example. In this work, we propose-to the best of our knowledge-the first VLSI design enabling high-throughput data detection in single-carrier frequency-division multiple access (SC-FDMA)-based large-scale MIMO systems. We propose a new approximate matrix inversion algorithm relying on a Neumann series expansion, which substantially reduces the complexity of linear data detection. We analyze the associated error, and we compare its performance and complexity to those of an exact linear detector. We present corresponding VLSI architectures, which perform exact and approximate soft-output detection for large-scale MIMO systems with various antenna/user configurations. Reference implementation results for a Xilinx Virtex-7 XC7VX980T FPGA show that our designs are able to achieve more than 600 Mb/s for a 128 antenna, 8 user 3GPP LTE-based large-scale MIMO system. We finally provide a performance/complexity trade-off comparison using the presented FPGA designs, which reveals that the detector circuit of choice is determined by the ratio between BS antennas and users, as well as the desired error-rate performance.
Data detection in massive multi-user (MU) multiple-input multiple-output (MIMO) wireless systems is among the most critical tasks due to the excessively high implementation complexity. In this paper, ...we propose a novel, equalization-based soft-output data-detection algorithm and corresponding reference FPGA designs for wideband massive MU-MIMO systems that use orthogonal frequency-division multiplexing (OFDM). Our data-detection algorithm performs approximate minimum mean-square error (MMSE) or box-constrained equalization using coordinate descent. We deploy a variety of algorithm-level optimizations that enable near-optimal error-rate performance at low implementation complexity, even for systems with hundreds of base-station (BS) antennas and thousands of subcarriers. We design a parallel VLSI architecture that uses pipeline interleaving and can be parametrized at design time to support various antenna configurations. We develop reference FPGA designs for massive MU-MIMO-OFDM systems and provide an extensive comparison to existing designs in terms of implementation complexity, throughput, and error-rate performance. For a 128 BS antenna, 8-user massive MU-MIMO-OFDM system, our FPGA design outperforms the next-best implementation by more than 2.6 \times in terms of throughput per FPGA look-up tables.
This paper proposes a novel time-based method for determining the position of an IEEE 802.11g transmitter using multiple mutually synchronized 802.11g receivers. By means of baseband signal ...processing, the proposed algorithm obtains a high-resolution estimate of the time of arrival (TOA) of the long training sequence symbol at each receiver. An estimate of the position of the transmitter is obtained based on the estimation of the time differences of arrival (TDOA) of the symbols and the known fixed locations of the receivers. This paper investigates the effects of carrier and sampling clock offsets, in both frequency and phase, between nodes on the TOA and TDOA estimation error. In real-world experiments in a line of sight, low multipath indoor environment, the method was found to achieve mean errors of 42 cm per symbol for 1-D and 1.39 m per symbol for 2-D position estimation, for ranges of up to 25 m.
Non-binary low-density parity-check (NB-LDPC) codes show higher error-correcting performance than binary low-density parity-check (LDPC) codes when the codeword length is moderate and/or the channel ...has bursts of errors. The need for high-speed decoders for future digital communications led to the investigation of optimized NB-LDPC decoding algorithms and efficient implementations that target high throughput and low energy consumption levels. We carried out a comprehensive survey of existing NB-LDPC decoding hardware that targets the optimization of these parameters. Even though existing NB-LDPC decoders are optimized with respect to computational complexity and memory requirements, they still lag behind their binary counterparts in terms of throughput, power and area optimization. This study contributes to an overall understanding of the state-of-the-art on application-specific integrated-circuit (ASIC), field-programmable gate array (FPGA) and graphics processing units (GPU) based systems, and highlights the current challenges that still have to be overcome on the path to more efficient NB-LDPC decoder architectures.
Progesterone is essential for the maintenance of pregnancy. However, whether progesterone supplementation in the first trimester of pregnancy would increase the rate of live births among women with a ...history of unexplained recurrent miscarriages is uncertain.
We conducted a multicenter, double-blind, placebo-controlled, randomized trial to investigate whether treatment with progesterone would increase the rates of live births and newborn survival among women with unexplained recurrent miscarriage. We randomly assigned women with recurrent miscarriages to receive twice-daily vaginal suppositories containing either 400 mg of micronized progesterone or matched placebo from a time soon after a positive urinary pregnancy test (and no later than 6 weeks of gestation) through 12 weeks of gestation. The primary outcome was live birth after 24 weeks of gestation.
A total of 1568 women were assessed for eligibility, and 836 of these women who conceived naturally within 1 year and remained willing to participate in the trial were randomly assigned to receive either progesterone (404 women) or placebo (432 women). The follow-up rate for the primary outcome was 98.8% (826 of 836 women). In an intention-to-treat analysis, the rate of live births was 65.8% (262 of 398 women) in the progesterone group and 63.3% (271 of 428 women) in the placebo group (relative rate, 1.04; 95% confidence interval CI, 0.94 to 1.15; rate difference, 2.5 percentage points; 95% CI, -4.0 to 9.0). There were no significant between-group differences in the rate of adverse events.
Progesterone therapy in the first trimester of pregnancy did not result in a significantly higher rate of live births among women with a history of unexplained recurrent miscarriages. (Funded by the United Kingdom National Institute of Health Research; PROMISE Current Controlled Trials number, ISRCTN92644181.).
We present an efficient VLSI architecture for 3GPP LTE/LTE-Advance Turbo decoder by utilizing the algebraic-geometric properties of the quadratic permutation polynomial (QPP) interleaver. The ...high-throughput 3GPP LTE/LTE-Advance Turbo codes require a highly-parallel decoder architecture. Turbo interleaver is known to be the main obstacle to the decoder parallelism due to the collisions it introduces in accesses to memory. The QPP interleaver solves the memory contention issues when several MAP decoders are used in parallel to improve Turbo decoding throughput. In this paper, we propose a low-complexity QPP interleaving address generator and a multi-bank memory architecture to enable parallel Turbo decoding. Design trade-offs in terms of area and throughput efficiency are explored to find the optimal architecture. The proposed parallel Turbo decoder has been synthesized, placed and routed in a 65-nm CMOS technology with a core area of 8.3
mm
2 and a maximum clock frequency of 400
MHz. This parallel decoder, comprising 64 MAP decoder cores, can achieve a maximum decoding throughput of 1.28
Gbps at 6 iterations
Introduction
Treatment-resistant schizophrenia (TRS) represents a major clinical issue, characterized by worse psychopathological outcome, a more disrupted neurobiological substrate and higher ...healthcare costs. Cognitive impairment is a core feature of schizophrenia, strongly associated with patients’ functional outcome. Different studies showed that TRS patients exhibit poorer neurocognitive performance, particularly on verbal domains. To date Cognitive Remediation Therapy (CRT) represents the best available tool for treating cognitive deficits in schizophrenia. However, CRT outcomes are highly heterogeneous and significant treatment predictors are still lacking.
Objectives
To investigate possible differences of CRT outcome among patients with schizophrenia, stratified according to antipsychotic response (TRSs vs. first-line responders - FLRs).
Methods
150 patients with schizophrenia, (95 FLRs, 55 TRSs) were assessed for neurocognition with BACS and WCST at baseline and after CRT. General Linear Models (GLMs) were performed to investigate possible differences between groups on basal cognition and CRT outcome (Cohen’s d Effect Size).
Results
At baseline, GLMs showed significant differences in Verbal Memory (F=4,66; p=0,03) and WCST–executive functions (F=5,59; p=0,02), both worse in TRS group. Effecr Sizes of CRT outcome resulted significantly different in domains of Verbal Memory (F=4,68; p=0,03) and WCST–executive functions (F=4,62; p=0,03), with greater improvements among TRS patients.
Conclusions
This is the first study to indicate treatment-resistance as a possible predictor of CRT outcome in schizophrenia. Moreover, we observed that CRT resulted able to fill the cognitive gap between treatment groups. Thus, these results further highlight the importance of early cognitive interventions in order to reduce the neuropsychological and functional burden associated with the disease, especially for TRS patients.
Disclosure
No significant relationships.
GPU-Based, LDPC Decoding for 5G and Beyond Tarver, Chance; Tonnemacher, Matthew; Chen, Hao ...
IEEE open journal of circuits and systems,
2021, Letnik:
2
Journal Article
Recenzirano
Odprti dostop
In 5G New Radio (NR), low-density parity-check (LDPC) codes are included as the error correction codes (ECC) for the data channel. While LDPC codes enable a low, near Shannon capacity, bit error rate ...(BER), they also become a computational bottleneck in the physical layer processing. Moreover, 5G LDPC has new challenges not seen in previous LDPC implementations, such as Wi-Fi. The LDPC specification in 5G includes many reconfigurations to support a variety of rates, block sizes, and use cases. 5G also creates targets for supporting high-throughput and low-latency applications. For this new, flexible standard, traditional hardware-based solutions in FGPA and ASIC may struggle to support all cases and may be cost-prohibitive at scale. Software solutions can trivially support all possible reconfigurations but struggle with performance. This article demonstrates the high-throughput and low-latency capabilities of graphics processing units (GPUs) for LDPC decoding as an alternative to FPGA and ASIC decoders, effectively providing the high performance needed while maintaining the benefits of a software-based solution. In particular, we highlight how by varying the parallelization strategy for mapping GPU kernels to blocks, we can use the many GPU cores to compute one codeword quickly to target low-latency, or we can use the cores to work on many codewords simultaneously to target high throughput applications. This flexibility is particularly useful for virtualized radio access networks (vRAN), a next-generation technology that is expected to become more prominent in the coming years. In vRAN, the hardware computational resources will become decoupled from the specific computational functions in the RAN through virtualization, allowing for benefits such as load-balancing, improved scalability, and reduced costs. To highlight and investigate how the GPU can accelerate tasks such as LDPC decoding when containerizing vRAN functionality, we integrate our decoder into the Open Air Interface (OAI) NR software stack. With our GPU-based decoder, we measure a best case-latency of <inline-formula> <tex-math notation="LaTeX">87~\mu \text{s} </tex-math></inline-formula> and a best-case throughput of nearly 4 Gbps using the Titan RTX GPU.
Introduction
Deficit in Theory of Mind (ToM) is a core feature of schizophrenia (SZ), while adverse childhood experiences (ACEs) can contribute to worsen ToM abilities through their effect on brain ...functioning, structure and connectivity.
Objectives
Here, we investigated the effects of ACEs on brain functional connectivity (FC) during an affective and cognitive ToM task (AToM, CToM) in healthy control (HC) and SZ, and whether FC can predict the performance at the ToM task and patients’ symptoms severity.
Methods
The sample included 26 HC and 33 SZ. In an fMRI session, participants performed a ToM task targeting affective and cognitive domains. Whole-brain FC patterns of local correlation (LC) and multivariate pattern analysis (MVPA) were extracted. The significant MVPA clusters were used as seeds in further seed-based connectivity analyses. Second-level analyses were modelled to investigate the interaction between ACEs, the diagnosis, and the task, corrected for age, sex, and equivalent doses of chlorpromazine (p<0.05 FWE). FC values significantly affected by ACEs (Risky Family Questionnaire) were entered in a cross-validated LASSO regression predicting symptoms severity (Positive and Negative Syndrome Scale, PANSS) and task performance measures (accuracy and response time).
Results
In AToM, LC showed significant different effects of ACE between HC and SZ in frontal pole, caudate and cerebellum. MVPA showed significant widespread interaction in cortico-limbic regions, including prefrontal cortex, precuneus, insula, parahippocampus, cingulate cortex, temporal pole, thalamus, and cerebellum in AToM and CToM. SBC analyses found significant target regions in the frontal pole, cerebellum, pre and postcentral gyrus, precuneus, lateral occipital cortex, angular gyrus, and paracingulate gyrus. LASSO regression predicted PANSS score (R
2
=0.49) and AToM response latency time (R
2
=0.37).
Conclusions
Our findings highlighted a widespread different effect of ACEs on brain FC in ToM networks in HC and SZ. Notably, the FC in these regions is predictive of behavioral ToM performance and clinical outcomes.
Disclosure of Interest
None Declared
Dynamic aeroelastic behavior of a joined-wing PrandtlPlane configuration is investigated herein. The baseline model is obtained from a configuration previously designed by partner universities ...through several multidisciplinary optimizations and ad hoc analyses, including detailed studies on the layout of control architecture. An equivalent structural model has then been adopted to qualitatively retain similar aeroelastic properties.
Flutter and post-flutter regimes, including limit cycle oscillations (LCOs), are studied. A detailed analysis of the energy transfer between fluid and structure is carried out; the areas in which energy is extracted from the fluid are identified to gain insights on the mechanism leading to the aeroelastic instability. Starting from an existing design of control surfaces on the baseline configuration, freeplay is also considered and its effects on the aeroelastic stability properties of the joined-wing system are investigated for the first time.
Both cantilever and free flying configurations are analyzed. Fuselage inertial effects are modeled and the aeroelastic properties are studied considering plunging and pitching rigid body modes. For this configuration a positive interaction between elastic and rigid body modes yields a flutter-free design (within the range of considered airspeeds).
To understand the sensitivity of the system and gain insight, fuselage mass and moment of inertia are selectively varied. For a fixed pitching moment of inertia, larger fuselage mass favors body freedom flutter. When the moment of inertia is varied, a change of critical properties is observed. For smaller values the pitching mode becomes unstable, and coalescence is observed between pitching and the first elastic mode. Increasing pitching inertia, the above criticality is postponed; meanwhile, the second elastic mode becomes unstable at progressively lower speeds. For larger inertial values “cantilever” flutter properties, having coalescence of first and second elastic modes, are recovered.
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