| 1. |
- Bezati, Endri, et al.
(författare)
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High-level system synthesis and optimization of dataflow programs for MPSoCs
- 2017
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Ingår i: 50th Asilomar Conference on Signals, Systems and Computers, ACSSC 2016. - 9781538639542 ; , s. 417-421
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Konferensbidrag (refereegranskat)abstract
- The growing complexity of digital signal processing applications make a compelling case the use of high-level design and synthesis methodologies for the implementation on reconfigurable and embedded devices. Past research has shown that raising the level of abstraction of design stages does not necessarily gives penalties in terms of performance or resources. Dataflow programs provide behavioral descriptions capable of expressing both sequential and parallel algorithms and enable natural design abstractions, modularity, and portability. In this paper, a tool implementing dataflow programs onto embedded heterogeneous platforms by means of high-level synthesis, software synthesis and interface synthesis is presented for MPSoCs platfroms.
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| 2. |
- Elvander, Filip, et al.
(författare)
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Time Recursive Multi-Pitch Estimation Using Group Sparse Recursive Least Squares
- 2017
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Ingår i: 50th Asilomar Conference on Signals, Systems, and Computers, 2016. - 9781538639542 ; , s. 369-373
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Konferensbidrag (refereegranskat)abstract
- In this work, we propose a time-recursive multi-pitch estimation algorithm, using a sparse reconstruction framework, assuming only a few pitches from a large set of candidates to be active at each time instant. The proposed algorithm utilizes a sparse recursive least squares formulation augmented by an adaptive penalty term specifically designed to enforce a pitch structure on the solution. When evaluated on a set of ten music pieces, the proposed method is shown to outperform state-of-the-art multi-pitch estimators in either accuracy or computational spe
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| 3. |
- Gharanjik, A., et al.
(författare)
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Max-min transmit beamforming via iterative regularization
- 2017
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Ingår i: Conference Record - Asilomar Conference on Signals, Systems and Computers. - : IEEE Computer Society. - 9781538639542 ; , s. 1437-1441
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Konferensbidrag (refereegranskat)abstract
- This paper introduces an iterative optimization framework to tackle the multi-group multicast Max-Min transmit beamforming problem. In each iteration, the optimization problem is decomposed into four sub-problems, all of which can be solved using computationally efficient algorithms. The advantage of proposed method lies in its ability to handle different types of signal constraints like total power and unimodularity; a feature not exhibited by other techniques. The proposed technique outperforms the well-known semidefinite relaxation method in terms of quality of solutions.
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| 4. |
- Hu, Sha, et al.
(författare)
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Massive MIMO via Cooperative Users
- 2017
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Ingår i: 50th Asilomar Conference on Signals, Systems and Computers, 2016. - 9781538639542 ; , s. 177-182
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Konferensbidrag (refereegranskat)abstract
- We consider a case where K closely located users communicate with a base station in the uplink of a wireless communication system. Each user has a certain number of assigned time-frequency slots at its disposal. At a small cost, which we in this paper consider as negliable, the users can communicate with each other and share their data. Thus, they can cooperate in the uplink in order to save transmit power. When many single-antenna users cooperate tightly to enhance their communication using maximum-ratio transmission, they essentially form a massive MIMO array. We investigate the case with a single receiving base station antenna, but the same general principle applies with multiple receiving antennas. We formulate a game theoretic model for this, and study what savings are possible, and to what extent users are willing to take part in the cooperation. Our findings are that large gains are possible, and that all users cooperate. Further, users are able to establish their transmit powers without any moderator.
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| 5. |
- Kronvall, Ted, et al.
(författare)
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Hyperparameter-free sparse regression of grouped variables
- 2017
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Ingår i: Conference Record of the 50th Asilomar Conference on Signals, Systems and Computers, ACSSC 2016. - 9781538639542 ; , s. 394-398
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Konferensbidrag (refereegranskat)abstract
- In this paper, we introduce a novel framework for semi-parametric estimation of an unknown number of signals, each parametrized by a group of components. Via a reformulation of the covariance fitting criteria, we formulate a convex optimization problem over a grid of candidate representations, promoting solutions with only a few active groups. Utilizing the covariance fitting allows for a hyperparameter-free estimation procedure, highly robust against coherency between candidates, while still allowing for a computationally efficient implementation. Numerical simulations illustrate how the proposed method offers a performance similar to the group-LASSO for incoherent dictionaries, and superior performance for coherent dictionaries.
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| 6. |
- Magesacher, Thomas, et al.
(författare)
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Benchmarking of learning architectures for digital predistortion
- 2017
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Ingår i: Conference Record of the 50th Asilomar Conference on Signals, Systems and Computers, ACSSC 2016. - 9781538639542 ; , s. 648-651
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Konferensbidrag (refereegranskat)abstract
- Indirect and direct learning architectures are the two main parameter identification approaches for digital predistortion systems. While the indirect scheme is less complex, its inherent shortcomings are avoided by the direct learning approach. Trying to answer the question whether this advantage of the direct approach can be exploited in terms of measurable linearization-performance improvement in a predistortion platform for advanced power amplifier structures, we present a performance comparison based on laboratory results for wideband high-power Doherty amplifiers. Rather than using single-shot least-squares estimates, each architecture is combined with an adaptive parameter-update scheme to reach the desired performance range and allow for a fair comparison. In conclusion, although the direct learning approach may excel in peak performance, the indirect learning approach achieves virtually the same average performance over linearization runs and has a clear advantage in terms of robustness.
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| 7. |
- Michalska-Jakubus, Malgorzata, et al.
(författare)
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Trace-based manycore partitioning of stream-processing applications
- 2017
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Ingår i: Conference Record of the 50th Asilomar Conference on Signals, Systems and Computers, ACSSC 2016. - 9781538639542 ; , s. 422-426
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Konferensbidrag (refereegranskat)abstract
- Application performance on these processor array platforms is highly sensitive to how functionality is physically placed on the device, as this choice crucially determines communication latencies and congestion patterns of the on-chip inter-core communication. The problem of identifying the best, or just a good enough, partitioning and placement does not, in general, admit to an analytic solution, and its combinatorial nature makes solving it by pure experimentation impractical. This paper presents an approach that maps stream programs onto processor arrays using trace analysis as a technique for evaluating candidate solutions and for suggesting alternatives.
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| 8. |
- Sarajlic, Muris, et al.
(författare)
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An Energy Efficiency Perspective on Massive MIMO Quantization
- 2017
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Ingår i: Proceedings of the 50th Asilomar Conference on Signals, Systems and Computers. - 9781538639542 ; , s. 473-478
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the basic aspects of Massive MIMO (MaMi) that is in the focus of current investigations is its potential of using low-cost and energy-efficient hardware. It is often claimed that MaMi will allow for using analog-to-digital converters(ADCs) with very low resolutions and that this will result in overall improvement of energy efficiency. In this contribution, we perform a parametric energy efficiency analysis of MaMi uplink for the entire base station receiver system with varyingADC resolutions. The analysis shows that, for a wide variety of system parameters, ADCs with intermediate bit resolutions (4 - 10 bits) are optimal in energy efficiency sense, and that using very low bit resolutions results in degradation of energy efficiency.
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| 9. |
- Ugolini, Alessandro, et al.
(författare)
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Efficient satellite systems based on interference management and exploitation
- 2017
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Ingår i: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781538639542 ; , s. 492-496
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Konferensbidrag (refereegranskat)abstract
- © 2016 IEEE.We study the benefits arising from the exploitation of interference in two satellite communications scenarios. We show that promising gains, with respect to the classical interference avoidance approach, can be achieved by applying non-orthogonal transmission schemes together with advanced transceiver architectures. We demonstrate that the non-orthogonal solutions significantly outperform the classical ones in all analyzed scenarios, at the cost of an increased complexity.
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