64 research outputs found

    A Scalable VLSI Architecture for Soft-Input Soft-Output Depth-First Sphere Decoding

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    Multiple-input multiple-output (MIMO) wireless transmission imposes huge challenges on the design of efficient hardware architectures for iterative receivers. A major challenge is soft-input soft-output (SISO) MIMO demapping, often approached by sphere decoding (SD). In this paper, we introduce the - to our best knowledge - first VLSI architecture for SISO SD applying a single tree-search approach. Compared with a soft-output-only base architecture similar to the one proposed by Studer et al. in IEEE J-SAC 2008, the architectural modifications for soft input still allow a one-node-per-cycle execution. For a 4x4 16-QAM system, the area increases by 57% and the operating frequency degrades by 34% only.Comment: Accepted for IEEE Transactions on Circuits and Systems II Express Briefs, May 2010. This draft from April 2010 will not be updated any more. Please refer to IEEE Xplore for the final version. *) The final publication will appear with the modified title "A Scalable VLSI Architecture for Soft-Input Soft-Output Single Tree-Search Sphere Decoding

    A 2.78 mm2 65 nm CMOS Gigabit MIMO Iterative Detection and Decoding Receiver

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    Iterative detection and decoding (IDD), combined with spatial-multiplexing multiple-input multiple-output (MIMO) transmission, is a key technique to improve spectral efficiency in wireless communications. In this paper we present the—to the best of our knowledge—first complete silicon implementation of a MIMO IDD receiver. MIMO detection is performed by a multi-core sphere decoder supporting up to 4×4 as antenna configuration and 64-QAM modulation. A flexible low-density parity check decoder is used for forward error correction. The 65 nm CMOS ASIC has a core area of 2.78 mm2 . Its maximum throughput exceeds 1 Gbit/s, at less than 1 nJ/bit. The MIMO IDD ASIC enables more than 2 dB performance gains with respect to non-iterative receivers

    A seamless software defined radio development flow for waveform and prototype debugging, Journal of Telecommunications and Information Technology, 2008, nr 2

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    With the increasing number of wireless communication standards flexibility has gained more and more importance which has lead to the software defined radio (SDR) concept. However, SDR development has to face many challenges, among them are the questions how SDR systems can be designed to achieve flexibility, architectural efficiency, energy efficiency and portability at the same time. These requirements result in very elaborate architectures and a highly increased design complexity. To cope with such complexity, we proposed an SDR development flow. During the development of such SDR, debugging becomes more efficient on a prototype hardware implementation than on a simulation model. However, error analysis on a prototype suffers from strong limitations like a reduced state visibility. In this paper, an extension to the SDR development flow is presented and successfully applied to an example SDR. It allows for an efficient error analysis with the SDR simulation model by the feedback of stimulus data from the prototype

    The antisaccade task as an index of sustained goal activation in working memory: modulation by nicotine

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    The antisaccade task provides a laboratory analogue of situations in which execution of the correct behavioural response requires the suppression of a more prepotent or habitual response. Errors (failures to inhibit a reflexive prosaccade towards a sudden onset target) are significantly increased in patients with damage to the dorsolateral prefrontal cortex and patients with schizophrenia. Recent models of antisaccade performance suggest that errors are more likely to occur when the intention to initiate an antisaccade is insufficiently activated within working memory. Nicotine has been shown to enhance specific working memory processes in healthy adults. MATERIALS AND METHODS: We explored the effect of nicotine on antisaccade performance in a large sample (N = 44) of young adult smokers. Minimally abstinent participants attended two test sessions and were asked to smoke one of their own cigarettes between baseline and retest during one session only. RESULTS AND CONCLUSION: Nicotine reduced antisaccade errors and correct antisaccade latencies if delivered before optimum performance levels are achieved, suggesting that nicotine supports the activation of intentions in working memory during task performance. The implications of this research for current theoretical accounts of antisaccade performance, and for interpreting the increased rate of antisaccade errors found in some psychiatric patient groups are discussed

    The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

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    This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

    O31 Integrative analysis reveals a molecular stratification of systemic autoimmune diseases

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