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Oechtering, Tobias J.ORCID iD iconorcid.org/0000-0002-0036-9049
Alternative names
Publications (10 of 115) Show all publications
Do, T. T., Ngo, H. Q., Duong, T. Q., Oechtering, T. & Skoglund, M. (2017). Massive MIMO Pilot Retransmission Strategies for Robustification Against Jamming. IEEE Wireless Communications Letters, 6(1), 58-61.
Open this publication in new window or tab >>Massive MIMO Pilot Retransmission Strategies for Robustification Against Jamming
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2017 (English)In: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 6, no 1, 58-61 p.Article in journal (Refereed) Published
Abstract [en]

This letter proposes anti-jamming strategies based on pilot retransmission for a single user uplink massive MIMO under jamming attack. A jammer is assumed to attack the system both in the training and data transmission phases. We first derive an achievable rate which enables us to analyze the effect of jamming attacks on the system performance. Counter-attack strategies are then proposed to mitigate this effect under two different scenarios: random and deterministic jamming attacks. Numerical results illustrate our analysis and benefit of the proposed schemes.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2017
Keyword
Massive MIMO, jamming, pilot retransmission
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-205139 (URN)10.1109/LWC.2016.2631163 (DOI)000395868700015 ()2-s2.0-85013651383 (Scopus ID)
Note

QC 20170412

Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2017-11-29Bibliographically approved
Wiese, M. & Oechtering, T. J. (2017). Secure distributed estimation of linear systems. In: 2016 IEEE Conference on Communications and Network Security, CNS 2016: . Paper presented at 2016 IEEE Conference on Communications and Network Security, CNS 2016, 17 October 2016 through 19 October 2016 (pp. 616-620). Institute of Electrical and Electronics Engineers Inc..
Open this publication in new window or tab >>Secure distributed estimation of linear systems
2017 (English)In: 2016 IEEE Conference on Communications and Network Security, CNS 2016, Institute of Electrical and Electronics Engineers Inc. , 2017, 616-620 p.Conference paper, Published paper (Refereed)
Abstract [en]

A two-dimensional linear time-invariant system is considered. The two dimensions of its states are observed by one sensor each. Every sensor quantizes its observations into a finite number of messages, using also the other sensor's past decisions. The combined sensor outputs should allow for a bounded estimation error (reliability). For a natural quantizer, we identify the cases where a price in the quantizer sum rate has to be paid for the fact that observations are distributed. At the same time, an eavesdropper should not be able to track the system state (security). Using the same quantizer as before, security is shown to be possible if the eavesdropper has less information than the estimator in that it for each sensor message pair obtains a larger set of indistinguishable message pairs.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Keyword
Estimation, Invariance, Linear systems, Time varying control systems, Bounded estimation error, Combined sensors, Distributed estimation, Finite number, Linear time invariant systems, Message pairs, System state, Two-dimension, Network security
National Category
Control Engineering
Identifiers
urn:nbn:se:kth:diva-208001 (URN)10.1109/CNS.2016.7860559 (DOI)000402623000095 ()2-s2.0-85016060207 (Scopus ID)9781509030651 (ISBN)
Conference
2016 IEEE Conference on Communications and Network Security, CNS 2016, 17 October 2016 through 19 October 2016
Note

QC 2017-06-08

Available from: 2017-06-08 Created: 2017-06-08 Last updated: 2017-06-30Bibliographically approved
Do, T. T., Oechtering, T. J., Kim, S. M., Skoglund, M. & Peters, G. (2017). Uplink Waveform Channel With Imperfect Channel State Information and Finite Constellation Input. IEEE Transactions on Wireless Communications, 16(2), 1107-1119.
Open this publication in new window or tab >>Uplink Waveform Channel With Imperfect Channel State Information and Finite Constellation Input
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2017 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 16, no 2, 1107-1119 p.Article in journal (Refereed) Published
Abstract [en]

This paper investigates the capacity limit of an uplink waveform channel assuming imperfect channel state information at the receiver (CSIR). Various realistic assumptions are incorporated into the problem, which make the study valuable for performance assessment of real cellular networks to identify potentials for performance improvements in practical receiver designs. We assume that the continuous-time received signal is first discretized by mismatched filtering based on the imperfect CSIR. The resulting discrete-time signals are then decoded considering two different decoding strategies, i.e., an optimal decoding strategy based on specific statistics of channel estimation errors and a sub-optimal decoding strategy treating the estimation error signal as additive Gaussian noise. Motivated by the proposed decoding strategies, we study the performance of the decision feedback equalizer for finite constellation inputs, in which inter-stream interferences are treated either using their true statistics or as Gaussian noise. Numerical results are provided to exemplify the benefit of exploiting the knowledge on the statistics of the channel estimation errors and inter-stream interferences. Simulations also assess the effect of the CSI imperfectness on the achievable rate, which reveal that finite constellation inputs are less sensitive to the estimation accuracy than Gaussian input, especially in the high SNR regime.

Place, publisher, year, edition, pages
IEEE Press, 2017
Keyword
Finite constellation input, imperfect CSI, mismatched filtering, uplink waveform channel
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-204102 (URN)10.1109/TWC.2016.2638420 (DOI)000395825200034 ()2-s2.0-85014906082 (Scopus ID)
Note

QC 20170329

Available from: 2017-03-29 Created: 2017-03-29 Last updated: 2017-11-29Bibliographically approved
Zaidi, A. A., Yüksel, S., Oechtering, T. & Skoglund, M. (2016). On the tightness of linear policies for stabilization of linear systems over Gaussian networks. Systems & control letters (Print), 88, 32-38.
Open this publication in new window or tab >>On the tightness of linear policies for stabilization of linear systems over Gaussian networks
2016 (English)In: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 88, 32-38 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, we consider stabilization of multi-dimensional linear systems driven by Gaussian noise controlled over parallel Gaussian channels. For such systems, it has been recognized that for stabilization in the sense of asymptotic stationarity or stability in probability, Shannon capacity of a channel is an appropriate measure on characterizing whether a system can be made stable when controlled over the channel. However, this is in general not the case for quadratic stabilization. On a related problem of joint-source channel coding, in the information theory literature, the source-channel matching principle has been shown to lead to optimality of uncoded or analog transmission and when such matching conditions occur, it has been shown that capacity is also a relevant figure of merit for quadratic stabilization. A special case of this result is applicable to a scalar LQG system controlled over a scalar Gaussian channel. In this paper, we show that even in the absence of source-channel matching, to achieve quadratic stability, it may suffice that information capacity (in Shannon’s sense) is greater than the sum of the logarithm of unstable eigenvalue magnitudes. In particular, we show that periodic linear time varying coding policies are optimal in the sense of obtaining a finite second moment for the state of the system with minimum transmit power requirements for a large class of vector Gaussian channels. Our findings also extend the literature which has considered noise-free systems.

Place, publisher, year, edition, pages
Elsevier, 2016
Keyword
Channel capacity, Gaussian channels, Networked control systems, Stabilization
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-180930 (URN)10.1016/j.sysconle.2015.09.013 (DOI)000370101400004 ()2-s2.0-84951037908 (Scopus ID)
Note

QC 20160126

Available from: 2016-01-26 Created: 2016-01-25 Last updated: 2017-11-30Bibliographically approved
Cao, P., Oechtering, T., Schaefer, R. & Mikael, S. (2016). Optimal Transmit Strategy for MISO Channels with Joint Sum and Per-antenna Power Constraints [Letter to the editor]. IEEE Transactions on Signal Processing.
Open this publication in new window or tab >>Optimal Transmit Strategy for MISO Channels with Joint Sum and Per-antenna Power Constraints
2016 (English)In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476Article in journal, Letter (Refereed) Published
Abstract [en]

In this paper, we study an optimal transmit strategy for multiple-input single-output (MISO) Gaussian channels with joint sum and per-antenna power constraints. We study in detail the interesting case where the sum of the per-antenna power constraints is larger than sum power constraint. A closed-form characterization of an optimal beamforming strategy is derived.It is shown that we can always find an optimal beamforming transmit strategy that allocates the maximal sum power with phases matched to the complex channel coefficients. The main result is a simple recursive algorithm to compute the optimal power allocation. Whenever the optimal power allocation of the corresponding problem with sum power constraint only exceeds per-antenna power constraints, it is optimal to allocate maximal per-antenna power to those antennas to satisfy the per-antenna power constraints. The remaining power is divided amongst the other antennas whose optimal allocation follows from a reduced joint sum and per-antenna power constraints problem of smaller channel coefficient dimension and reduced sum power constraint. Finally, the theoretical results are illustrated by numerical examples.

Place, publisher, year, edition, pages
IEEE, 2016
Keyword
Sum power constraint, per-antenna power constraint, MISO, beamforming, transmit strategy, transmission rate.
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-187650 (URN)10.1109/TSP.2016.2563382 (DOI)000380117400016 ()2-s2.0-84980395633 (Scopus ID)
External cooperation:
Note

QC 20160607

Available from: 2016-05-25 Created: 2016-05-25 Last updated: 2017-11-30Bibliographically approved
Li, Z., Oechtering, T. & Skoglund, M. (2016). Privacy-Preserving Energy Flow Control in Smart Grids. In: Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) 2016: . Paper presented at IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) 2016, Shanghai, P. R. China, Mar. 20-25, 2016. IEEE.
Open this publication in new window or tab >>Privacy-Preserving Energy Flow Control in Smart Grids
2016 (English)In: Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) 2016, IEEE , 2016Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, an energy flow control strategy to reduce the smart meter privacy leakage is studied. The considered smart grid is equipped with an energy storage device. The privacy leakage is modeled as optimal Bayesian detections on the behaviors of the consumer made by an authorized adversary. To evaluate the privacy risk, a Bayesian detection-operational privacy leakage metric is proposed. The design of an optimal privacy-preserving energy control strategy can be formulated as a belief state MDP problem. Therefore, standard methods and algorithms can be utilized to obtain or to approximate the optimal control strategy. A simplified problem to design an instantaneous optimal privacy-preserving control strategy is also considered. It is shown that the problem of the instantaneous optimal control strategy design can be formulated as a set of linear programmings.

Place, publisher, year, edition, pages
IEEE, 2016
National Category
Communication Systems Control Engineering Signal Processing
Identifiers
urn:nbn:se:kth:diva-179716 (URN)10.1109/ICASSP.2016.7472066 (DOI)000388373402067 ()2-s2.0-84973382871 (Scopus ID)
Conference
IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) 2016, Shanghai, P. R. China, Mar. 20-25, 2016
Funder
Swedish Research Council, 2015-06815
Note

QC 20160401

Available from: 2015-12-21 Created: 2015-12-21 Last updated: 2017-01-24Bibliographically approved
Do, T. T., Kim, S., Oechtering, T. J. & Peters, G. (2015). Capacity analysis of uplink WCDMA systems with imperfect channel state information. In: IEEE Vehicular Technology Conference: . Paper presented at 81st IEEE Vehicular Technology Conference, VTC Spring 2015, 11 May 2015 through 14 May 2015. IEEE.
Open this publication in new window or tab >>Capacity analysis of uplink WCDMA systems with imperfect channel state information
2015 (English)In: IEEE Vehicular Technology Conference, IEEE , 2015Conference paper, Published paper (Refereed)
Abstract [en]

This paper considers the capacity limit of an uplink wideband CDMA (WCDMA) system assuming imperfect channel state information at the receiver (CSIR). In order to make the studied results useful for the performance assessment of real cellular networks, various realistic assumptions are included in the problem. A discrete-time channel model is derived based on the mismatched filtering at the receiver. Capacity inner bounds are then characterized based on the discrete-time channel model considering different assumptions on decoding strategy. Numerical results are also provided to show the effect of imperfect CSIR on the capacity.

Place, publisher, year, edition, pages
IEEE, 2015
Keyword
Communication channels (information theory), Capacity analysis, Decoding strategy, Discrete-time channels, Imperfect channel state information, Mismatched filtering, Numerical results, Performance assessment, Wideband CDMA systems, Channel state information
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-175085 (URN)10.1109/VTCSpring.2015.7145727 (DOI)000371404700142 ()2-s2.0-84940426502 (Scopus ID)9781479980888 (ISBN)
Conference
81st IEEE Vehicular Technology Conference, VTC Spring 2015, 11 May 2015 through 14 May 2015
Note

QC 20151211

Available from: 2015-12-11 Created: 2015-10-09 Last updated: 2016-04-11Bibliographically approved
Kittichokechai, K., Oechtering, T. J. & Skoglund, M. (2015). Coding With Action-Dependent Side Information and Additional Reconstruction Requirements. IEEE Transactions on Information Theory, 61(11), 6355-6367.
Open this publication in new window or tab >>Coding With Action-Dependent Side Information and Additional Reconstruction Requirements
2015 (English)In: IEEE Transactions on Information Theory, ISSN 0018-9448, E-ISSN 1557-9654, Vol. 61, no 11, 6355-6367 p.Article in journal (Refereed) Published
Abstract [en]

Two classes of source/channel coding problems, namely, coding with action-dependent side information and coding with additional signal reconstruction are considered in a unified fashion. In the source coding setting, a decoder wishes to reconstruct the source subject to a distortion constraint, while an encoder is required to estimate the decoder's reconstruction reliably. Side information is action-dependent in the sense that its quality and/or availability at the encoder or decoder can be influenced by a cost-constrained action sequence. In the channel coding dual, the decoder wishes to decode both the message and the channel input sequence reliably, and the channel state information available at the encoder or decoder is assumed to depend on the action sequence. We consider discrete memoryless systems and characterize single letter expressions for the rate-distortion-cost function and channel capacity for the respective source and channel coding problems.

Place, publisher, year, edition, pages
IEEE, 2015
Keyword
Action, source coding with side information, channel with states, signal reconstruction, duality
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-177049 (URN)10.1109/TIT.2015.2476800 (DOI)000363256500039 ()2-s2.0-84959449757 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20151216

Available from: 2015-12-16 Created: 2015-11-13 Last updated: 2017-12-01Bibliographically approved
Goubet, O., Baudic, G., Gabry, F. & Oechtering, T. J. (2015). Low-Complexity Scalable Iterative Algorithms for IEEE 802.11p Receivers. IEEE Transactions on Vehicular Technology, 64(9), 3944-3956.
Open this publication in new window or tab >>Low-Complexity Scalable Iterative Algorithms for IEEE 802.11p Receivers
2015 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 64, no 9, 3944-3956 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, we investigate receivers for vehicle-to- vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. Vehicular channels are characterized by multiple paths and time variations, which introduce challenges in the design of receivers. We propose an algorithm for IEEE 802.11p-compliant receivers, based on orthogonal frequency-division multiplexing (OFDM). We employ iterative structures in the receiver as a way to estimate the channel despite variations within a frame. The channel estimator is based on factor graphs (FGs), which allow the design of soft iterative receivers while keeping acceptable computational complexity. Throughout this paper, we focus on designing a receiver that offers a good complexity-performance tradeoff. Moreover, we propose a scalable algorithm to be able to tune the tradeoff, depending on the channel conditions. Our algorithm allows reliable communications while offering a considerable decrease in computational complexity. In particular, numerical results show the tradeoff between complexity and performance measured in computational time and bit error rate (BER), as well as frame error rate (FER) achieved by various interpolation lengths used by the estimator, which both outperform by decades the standard least squares (LS) solution. Furthermore, our adaptive algorithm shows a considerable improvement in terms of computational time and complexity against state-of-the-art and classical receptors while showing acceptable BER and FER performance.

Keyword
Channel estimation, IEEE 802.11p standard, time-varying channels, vehicular technology, wireless communication
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-175508 (URN)10.1109/TVT.2014.2366155 (DOI)000361680900008 ()2-s2.0-84942357807 (Scopus ID)
Note

QC 20151021

Available from: 2015-10-21 Created: 2015-10-16 Last updated: 2017-12-01Bibliographically approved
Kim, S. M., Do, T. T., Oechtering, T. J. & Peters, G. (2015). On the Entropy Computation of Large Complex Gaussian Mixture Distributions. IEEE Transactions on Signal Processing, 63(17), 4710-4723.
Open this publication in new window or tab >>On the Entropy Computation of Large Complex Gaussian Mixture Distributions
2015 (English)In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 63, no 17, 4710-4723 p.Article in journal (Refereed) Published
Abstract [en]

The entropy computation of Gaussian mixture distributions with a large number of components has a prohibitive computational complexity. In this paper, we propose a novel approach exploiting the sphere decoding concept to bound and approximate such entropy terms with reduced complexity and good accuracy. Moreover, we propose an SNR region-based enhancement of the approximation method to reduce the complexity even further. Using Monte-Carlo simulations, the proposed methods are numerically demonstrated for the computation of the mutual information including the entropy term of various channels with finite constellation modulations such as binary and quadratic amplitude modulation (QAM) inputs for communication applications.

Keyword
Entropy approximation, finite input alphabet, Gaussian mixture distribution, mutual information, sphere decoding
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-173422 (URN)10.1109/TSP.2015.2441046 (DOI)000360064700021 ()2-s2.0-84939240423 (Scopus ID)
Note

QC 20150918

Available from: 2015-09-18 Created: 2015-09-11 Last updated: 2017-12-04Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0036-9049

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