| 1. |
- Fougstedt, Christoffer, 1990, et al.
(author)
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Power-Efficient Time-Domain Dispersion Compensation Using Optimized FIR Filter Implementation
- 2015
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In: Signal Processing in Photonics Communications, SPPCom 2015; Boston, MA; United States; 27 June 2015-1 July 2015. - 9781557520005 ; , s. SpT3D.3-
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Conference paper (peer-reviewed)abstract
- We investigate fixed-point aspects and time-domain ASIC implementations of CD compensation. An optimized implementation gives significant power dissipation reduction for short links, with further reduction if pulse shaping is considered.
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| 2. |
- LINDBERG, CHRISTOPHER, 1988, et al.
(author)
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Compressed Sensing in Wireless Sensor Networks without Explicit Position Information
- 2017
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In: IIEEE Transactions on Signal and Information Processing over Networks. - 2373-776X. ; 3:2, s. 404-415
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Journal article (peer-reviewed)abstract
- Reconstruction in compressed sensing relies on knowledge of a sparsifying transform. In a setting where a sink reconstructs a field based on measurements from a wireless sensor network, this transform is tied to the locations of the individual sensors, which may not be available to the sink during reconstruction. In contrast to previous works, we do not assume that the sink knows the position of each sensor to build up the sparsifying basis. Instead, we propose the use of spatial interpolation based on a predetermined sparsifying transform, followed by random linear projections and ratio consensus using local communication between sensors. For this proposed architecture, we upper bound the reconstruction error induced by spatial interpolation, as well as the reconstruction error induced by distributed compression. These upper bounds are then utilized to analyze the communication cost tradeoff between communication to the sink and sensor-to-sensor communication.
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| 3. |
- Sheikh, Alireza, 1989, et al.
(author)
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Dispersion Compensation Filter Design Optimized for Robustness and Power Efficiency
- 2015
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In: Signal Processing in Photonics Communications, SPPCom 2015; Boston, MA; United States; 27 June 2015 through 1 July 2015. - 9781557520005 ; , s. SpT3D.2-
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Conference paper (peer-reviewed)abstract
- We present an optimized CD compensation filter with improved performance and increased resilience to quantization errors. The filter is given in closed form based on a constrained least-squares problem.
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| 4. |
- Sheikh, Alireza, 1989, et al.
(author)
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Dispersion Compensation FIR Filter with Improved Robustness to Coefficient Quantization Errors
- 2016
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In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 34:22, s. 5110-5117
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Journal article (peer-reviewed)abstract
- In this paper, we propose a new finite impulseresponse (FIR) filter for chromatic dispersion compensation which is given in closed form. We identify a relation between the out-of-band gain and the in-band error when the filter is implemented with finite-precision arithmetic. In particular, a large out-of-band gain makes the filter more sensitive tocoefficient quantization errors due to finite precision digital signal processing. To improve robustness to coefficient quantization errors, our proposed filter is designed based on confining the out-of-band gain. By means of simulations, we show that our filter outperforms other existing FIR filters. The performance gain improves with increasing modulation order and decreasing number of bits used to represent the filter taps.
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| 5. |
- Andriyanova, Iryna, et al.
(author)
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Threshold Saturation for Nonbinary SC-LDPC Codes on the Binary Erasure Channel
- 2016
-
In: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 62:5, s. 2622-2638
-
Journal article (peer-reviewed)abstract
- We analyze the asymptotic performance of nonbinary spatially coupled low-density parity-check (SC-LDPC) code ensembles defined over the general linear group on the binary erasure channel. In particular, we prove the threshold saturation of belief propagation decoding to the so-called potential threshold, using the proof technique based on potential functions introduced by Yedla et al., assuming that the potential function exists. We rewrite the density evolution of nonbinary SC-LDPC codes in an equivalent vector recursion form which is suited for the use of the potential function. We then discuss the existence of the potential function for the general case of vector recursions defined by multivariate polynomials, and give a method to construct it. We define a potential function in a slightly more general form than the one by Yedla et al., in order to make the technique based on potential functions applicable to the case of nonbinary LDPC codes. We show that the potential function exists if a solution to a carefully designed system of linear equations exists. Furthermore, we numerically show the existence of a solution to the system of linear equations for a large number of nonbinary LDPC code ensembles, which allows us to define their potential function and thus prove threshold saturation.
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| 6. |
- Buchberger, Andreas, 1990, et al.
(author)
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Probabilistic Eigenvalue Shaping for Nonlinear Fourier Transform Transmission
- 2018
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In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 36:20, s. 4799-4807
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Journal article (peer-reviewed)abstract
- We consider a nonlinear Fourier transform (NFT)-based transmission scheme, where data is embedded into the imaginary part of the nonlinear discrete spectrum. Inspired by probabilistic amplitude shaping, we propose a probabilistic eigenvalue shaping (PES) scheme as a means to increase the data rate of the system. We exploit the fact that for an NFT-based transmission scheme the pulses in the time domain are of unequal duration by transmitting them with a dynamic symbol interval and find a capacity-achieving distribution. The PES scheme shapes the information symbols according to the capacity-achieving distribution and transmits them together with the parity symbols at the output of a low-density parity-check encoder, suitably modulated, via time-sharing. We furthermore derive an achievable rate for the proposed PES scheme. We verify our results with simulations of the discrete-time model as well as with split-step Fourier simulations.
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| 7. |
- Coskun, Mustafa Cemil, et al.
(author)
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Successive cancellation decoding of single parity-check product codes
- 2017
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In: IEEE International Symposium on Information Theory - Proceedings. - 2157-8095. - 9781509040964 ; , s. 1763-1767
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Conference paper (peer-reviewed)abstract
- Abstract:We introduce successive cancellation (SC) decoding of product codes (PCs) with single parity-check (SPC) component codes. Recursive formulas are derived, which resemble the SC decoding algorithm of polar codes. We analyze the error probability of SPC-PCs over the binary erasure channel under SC decoding. A bridge with the analysis of PCs introduced by Elias in 1954 is also established. Furthermore, bounds on the block error probability under SC decoding are provided, and compared to the bounds under the original decoding algorithm proposed by Elias. It is shown that SC decoding of SPC-PCs achieves a lower block error probability than Elias' decoding.
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| 8. |
- Fougstedt, Christoffer, 1990, et al.
(author)
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Energy-Efficient Soft-Assisted Product Decoders
- 2019
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In: 2019 Optical Fiber Communications Conference and Exhibition, OFC 2019 - Proceedings. - 9781943580538
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Conference paper (peer-reviewed)abstract
- We implement a 1-Tb/s 0.63-pJ/bit soft-assisted product decoder in a 28-nm technology. The decoder uses one bit of soft information to improve its net coding gain by 0.2 dB, reaching 10.3-10.4 dB, which is similar to that of more complex hard-decision staircase decoders.
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| 9. |
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| 10. |
- Graell i Amat, Alexandre, 1976, et al.
(author)
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Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall Region
- 2018
-
In: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 22:5, s. 886-889
-
Journal article (peer-reviewed)abstract
- A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored to the collision channel model, which enables mapping the description of the successive interference cancella- tion process onto the iterative erasure decoding of low-density parity-check codes. The analysis provides accurate estimates of the packet loss probability of IRSA in the waterfall region as demonstrated by Monte Carlo simulations.
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