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A. Mouris, B., Ghauch, H., Thobaben, R. & Jonsson, B. L. (2020). Multi-tone Signal Optimization for Wireless Power Transfer in the Presence of Wireless Communication Links. IEEE Transactions on Wireless Communications
Open this publication in new window or tab >>Multi-tone Signal Optimization for Wireless Power Transfer in the Presence of Wireless Communication Links
2020 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248Article in journal (Refereed) Published
Abstract [en]

In this paper, we study optimization of multi-tone signals for wireless power transfer (WPT) systems. We investigate different non-linear energy harvesting models. Two of them are adopted to optimize the multi-tone signal according to the channel state information available at the transmitter. We show that a second-order polynomial curve-fitting model can be utilized to optimize the multi-tone signal for any RF energy harvester design. We consider both single-antenna and multi-antenna WPT systems. In-band co-existing communication links are also considered in this work by imposing a constraint on the received power at the nearby information receiver to prevent its RF front end from saturation. We emphasize the importance of imposing such constraint by explaining how inter-modulation products, due to saturation, can cause high interference at the information receiver in the case of multi-tone signals. The multi-tone optimization problem is formulated as a non-convex linearly constrained quadratic program. Two globally optimal solution approaches using mixed-integer linear programming and finite branch-and-bound techniques are proposed to solve the problem. The achieved improvement resulting from applying both solution methods to the multi-tone optimization problem is highlighted through simulations and comparisons with other solutions existing in the literature.

National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-269164 (URN)10.1109/TWC.2020.2974950 (DOI)
Available from: 2020-03-04 Created: 2020-03-04 Last updated: 2020-03-04
A, Mouris, B., Fernàndez-Prieto, A., Thobaben, R., Martel, J., Mesa, F. & Quevedo-Teruel, O. (2020). On the Increment of the Bandwidth of Mushroom-Type EBG Structures With Glide Symmetry. IEEE transactions on microwave theory and techniques
Open this publication in new window or tab >>On the Increment of the Bandwidth of Mushroom-Type EBG Structures With Glide Symmetry
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2020 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670Article in journal (Refereed) Published
Abstract [en]

Mushroom-type electromagnetic bandgap (EBG) structures are known to operate as high-impedance surfaces at low-frequency bands. They are broadly used in the microwave regime. However, one of the main drawbacks of mushroom-type EBG structures is their narrow bandwidth. In this article, we propose a mushroom-type EBG structure with glide-symmetric edge vias to increase the operational bandwidth. This bandwidth increment is explained by the physical insight provided by an equivalent circuit model of the structure as well as the description of the field behavior. Simulation and measurement results show an improvement of approximately 67% over the case without glide symmetry in the structure. We conclude that applying glide symmetry to the mushroom-type EBG structures can improve their bandwidth without adding additional manufacturing costs.

National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-269163 (URN)10.1109/TMTT.2020.2966700 (DOI)
Available from: 2020-03-04 Created: 2020-03-04 Last updated: 2020-03-04
Rodríguez Gálvez, B., Thobaben, R. & Skoglund, M. (2020). The Convex Information Bottleneck Lagrangian. Entropy, 22(1), Article ID 98.
Open this publication in new window or tab >>The Convex Information Bottleneck Lagrangian
2020 (English)In: Entropy, ISSN 1099-4300, E-ISSN 1099-4300, Vol. 22, no 1, article id 98Article in journal (Refereed) Published
Abstract [en]

The information bottleneck (IB) problem tackles the issue of obtaining relevant compressedrepresentations T of some random variable X for the task of predicting Y. It is defined as a constrainedoptimization problem that maximizes the information the representation has about the task, I(T;Y) ,while ensuring that a certain level of compression r is achieved (i.e., I(X;T) ≤ r). For practical reasons,the problem is usually solved by maximizing the IB Lagrangian for many values of the Lagrange multiplier. Then, the curve of maximal I(T;Y) for a givenI(X;T) is drawn anda representation with the desired predictability and compression is selected. It is known when Yis a deterministic function of X, the IB curve cannot be explored and another Lagrangian has beenproposed to tackle this problem: the squared IB Lagrangian. In this paper, we (i) present a general family of Lagrangians which allow for the exploration of the IBcurve in all scenarios; (ii) provide the exact one-to-one mapping between the Lagrange multiplierand the desired compression rate r for known IB curve shapes; and (iii) show we can approximatelyobtain a specific compression level with the convex IB Lagrangian for both known and unknown IBcurve shapes. This eliminates the burden of solving the optimization problem for many values of theLagrange multiplier. That is, we prove that we can solve the original constrained problem with asingle optimization.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
information bottleneck; representation learning; mutual information; optimization
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-266691 (URN)10.3390/e22010098 (DOI)2-s2.0-85078523691 (Scopus ID)
Note

QC 20200120

Available from: 2020-01-16 Created: 2020-01-16 Last updated: 2020-02-04Bibliographically approved
A. Mouris, B., Kolitsidas, C. & Thobaben, R. (2019). A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power. In: A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power: . Paper presented at 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting. IEEE
Open this publication in new window or tab >>A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power
2019 (English)In: A Dual-Polarized Multi-Antenna Structure for Simultaneous Transmission of Wireless Information and Power, IEEE, 2019Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, a dual-polarized multi-antenna structure is designed at 2.45 GHz with the goal of allowing simultaneous transmission of wireless information and power. Differential feeding was used to minimize the mutual coupling due to radiation leakage in addition to a mushroom-type EBG structure for suppressing the surface waves. Simulation results for the proposed structure show a mutual coupling level lower than -40 dB between the information transmitting antenna and the power transmitting antennas for both polarizations. The isolation level between the antennas is improved by at least 22 dB and 14 dB for the E-plane and H-plane coupling, respectively.

Place, publisher, year, edition, pages
IEEE, 2019
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-269165 (URN)10.1109/APUSNCURSINRSM.2019.8889079 (DOI)978-1-7281-0692-2 (ISBN)
Conference
2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting
Available from: 2020-03-04 Created: 2020-03-04 Last updated: 2020-03-04
Forssell, K. H., Thobaben, R. & Gross, J. (2019). Performance Analysis of Distributed SIMO Physical Layer Authentication. In: ICC 2019 - 2019 IEEE International Conference on Communications (ICC): . Paper presented at 2019 IEEE International Conference on Communications, ICC 2019; Shanghai International Convention Center, Shanghai; China; 20-24 May 2019. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8761666.
Open this publication in new window or tab >>Performance Analysis of Distributed SIMO Physical Layer Authentication
2019 (English)In: ICC 2019 - 2019 IEEE International Conference on Communications (ICC), Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8761666Conference paper, Published paper (Refereed)
Abstract [en]

This paper proposes a new approach for physical layer authentication where transmissions are authenticated based on the single-input/multiple-output channel-states observed at multiple distributed antenna-arrays. The receiver operating characteristics (ROC) are derived in terms of closed form expressions for the false alarm and missed detection probability in order to evaluate the effectiveness compared to single-array authentication. To this end, we study the worst-case missed detection probability based on the optimal attacker position. Finally, we apply our previously developed queueing analytical tools, based on stochastic network calculus, in order to assess the delay performance impacts of the physical layer authentication scheme in a mission-critical communication scenario. Our results show that the distributed approach significantly outperforms single-array authentication in terms of worst-case missed detection probability and that this can help mitigating the delay performance impacts of authentication false alarms.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Series
IEEE International Conference on Communications, ISSN 1550-3607 ; 8761666
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-258169 (URN)10.1109/ICC.2019.8761666 (DOI)000492038803139 ()2-s2.0-85070211836 (Scopus ID)9781538680889 (ISBN)
Conference
2019 IEEE International Conference on Communications, ICC 2019; Shanghai International Convention Center, Shanghai; China; 20-24 May 2019
Projects
CERCES
Note

QC 20190910

Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2020-01-07Bibliographically approved
Forssell, H., Thobaben, R., Al-Zubaidy, H. & Gross, J. (2019). Physical Layer Authentication in Mission-Critical MTC Networks: A Security and Delay Performance Analysis. IEEE Journal on Selected Areas in Communications, 37(4), 795-808
Open this publication in new window or tab >>Physical Layer Authentication in Mission-Critical MTC Networks: A Security and Delay Performance Analysis
2019 (English)In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 37, no 4, p. 795-808Article in journal (Refereed) Published
Abstract [en]

We study the detection and delay performance impacts of a feature-based physical layer authentication (PLA) protocol in mission-critical machine-type communication (MTC) networks. The PLA protocol uses generalized likelihood-ratio testing based on the line-of-sight (LOS), single-input multiple- output channel-state information in order to mitigate imper- sonation attempts from an adversary node. We study the de- tection performance, develop a queueing model that captures the delay impacts of erroneous decisions in the PLA (i.e., the false alarms and missed detections), and model three different adversary strategies: data injection, disassociation, and Sybil attacks. Our main contribution is the derivation of analytical delay performance bounds that allow us to quantify the delay introduced by PLA that potentially can degrade the performance in mission-critical MTC networks. For the delay analysis, we utilize tools from stochastic network calculus. Our results show that with a sufficient number of receive antennas (approx. 4-8) and sufficiently strong LOS components from legitimate devices, PLA is a viable option for securing mission-critical MTC systems, despite the low latency requirements associated to corresponding use cases. Furthermore, we find that PLA can be very effective in detecting the considered attacks, and in particular, it can significantly reduce the delay impacts of disassociation and Sybil attacks.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
National Category
Communication Systems
Research subject
Telecommunication
Identifiers
urn:nbn:se:kth:diva-245235 (URN)10.1109/JSAC.2019.2899421 (DOI)000461853500008 ()2-s2.0-85061989373 (Scopus ID)
Projects
CERCES
Note

QC 20191120

Available from: 2019-03-07 Created: 2019-03-07 Last updated: 2019-11-20Bibliographically approved
Mouris, B. A., Quevedo-Teruel, O. & Thobaben, R. (2018). Exploiting Glide Symmetry in Planar EBG Structures. Paper presented at 2017 3rd International Workshop on Metamaterial-by-Design: Theory, Methods, and Applications to Communications and Sensing, Madrid, Spain, 14 December 2017 through 15 December 2017. Journal of Physics, Conference Series, 963(1), Article ID 012002.
Open this publication in new window or tab >>Exploiting Glide Symmetry in Planar EBG Structures
2018 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 963, no 1, article id 012002Article in journal (Refereed) Published
Abstract [en]

Periodic structures such as electromagnetic band gap (EBG) structures can be used to prevent the propagation of electromagnetic waves within a certain frequency range known as the stop band. One of the main limitations of using EBG structures at low frequencies is their relatively large size. In this paper, we investigate the possibility of using glide symmetry in planar EBG structures to reduce their size. Simulated results demonstrate that exploiting glide symmetry in EBG structures can lead to size reduction.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2018
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-224237 (URN)10.1088/1742-6596/963/1/012002 (DOI)000435022800002 ()2-s2.0-85043258367 (Scopus ID)
Conference
2017 3rd International Workshop on Metamaterial-by-Design: Theory, Methods, and Applications to Communications and Sensing, Madrid, Spain, 14 December 2017 through 15 December 2017
Note

QC 20180315

Available from: 2018-03-15 Created: 2018-03-15 Last updated: 2018-07-02Bibliographically approved
Forssell, H., Thobaben, R., Al-Zubaidy, H. & Gross, J. (2017). On the Impact of Feature-Based Physical Layer Authentication on Network Delay Performance. In: Globecom 2017 - 2017 IEEE Global Communications Conference: . Paper presented at IEEE Global Communications Conference (GLOBECOM), DEC 04-08, 2017, Your, Singapore. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>On the Impact of Feature-Based Physical Layer Authentication on Network Delay Performance
2017 (English)In: Globecom 2017 - 2017 IEEE Global Communications Conference, Institute of Electrical and Electronics Engineers (IEEE), 2017Conference paper, Published paper (Refereed)
Abstract [en]

Feature-based authentication schemes that verify wireless transmitter identities based on physical-layer features allow for fast and efficient authentication with minimal overhead. Hence, they are interesting to consider for safety-critical applications where low latency and high reliability is required. However, as erroneous authentication decisions will introduce delays, we propose to study the impact of feature-based schemes on the system-level performance. In this paper, we therefore study the queuing performance of a line-of-sight wireless link that employs a feature-based authentication scheme based on the complex channel gain. Using stochastic networks calculus, we provide bounds on the delay performance which are validated by numerical simulations. The results show that the delay and authentication performance is highly dependent on the SNR and Rice factor. However, under good channel conditions, a missed-detection rate of 10(-8) can be achieved without introducing excessive delays in the system.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Series
IEEE Global Communications Conference, ISSN 2334-0983
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-226848 (URN)10.1109/GLOCOM.2017.8254003 (DOI)000428054300083 ()2-s2.0-85046437823 (Scopus ID)978-1-5090-5019-2 (ISBN)
Conference
IEEE Global Communications Conference (GLOBECOM), DEC 04-08, 2017, Your, Singapore
Projects
CERCES
Funder
Swedish Civil Contingencies Agency
Note

QC 20180507

Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2018-06-25Bibliographically approved
Grosjean, L., Thobaben, R., Rasmussen, L. K. & Skoglund, M. (2016). Variable-rate anytime transmission with feedback. In: IEEE Vehicular Technology Conference: . Paper presented at 84th IEEE Vehicular Technology Conference, VTC Fall 2016, 18 September 2016 through 21 September 2016. IEEE, Article ID 7881963.
Open this publication in new window or tab >>Variable-rate anytime transmission with feedback
2016 (English)In: IEEE Vehicular Technology Conference, IEEE, 2016, article id 7881963Conference paper, Published paper (Refereed)
Abstract [en]

A generalization of the ensemble of non-terminated systematic LDPC convolutional codes developed in our previous work is proposed that allows us to design codes with lower rates than the original structure. We show that over the BEC, the modified codes have improved asymptotic and finite-length behavior and we determine the operational anytime exponent. Having shown the advantages of lowering the rate of the code, we propose a feedback protocol that permits encoder and decoder to operate at a variable rate. The rate is set on-the-fly and depends on the decoding success of the decoder. We describe the construction of the variable rate code structure and demonstrate by simulations the superiority of the variable rate scheme as compared to a scheme using a fixed rate.

Place, publisher, year, edition, pages
IEEE, 2016
Keywords
Convolutional codes, Decoding, Design codes, Feedback protocol, Finite length, LDPC convolutional codes, On the flies, Original structures, Variable rate, Variable rate codes, Codes (symbols)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-210142 (URN)10.1109/VTCFall.2016.7881963 (DOI)000402610200441 ()2-s2.0-85016981677 (Scopus ID)9781509017010 (ISBN)
Conference
84th IEEE Vehicular Technology Conference, VTC Fall 2016, 18 September 2016 through 21 September 2016
Note

QC 20170630

Available from: 2017-06-30 Created: 2017-06-30 Last updated: 2017-06-30Bibliographically approved
Si, Z., Ma, J. & Thobaben, R. (2015). Coded Cooperation for Multiway Relaying in Wireless Sensor Networks. Sensors, 15(7), 15265-15284
Open this publication in new window or tab >>Coded Cooperation for Multiway Relaying in Wireless Sensor Networks
2015 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 7, p. 15265-15284Article in journal (Refereed) Published
Abstract [en]

Wireless sensor networks have been considered as an enabling technology for constructing smart cities. One important feature of wireless sensor networks is that the sensor nodes collaborate in some manner for communications. In this manuscript, we focus on the model of multiway relaying with full data exchange where each user wants to transmit and receive data to and from all other users in the network. We derive the capacity region for this specific model and propose a coding strategy through coset encoding. To obtain good performance with practical codes, we choose spatially-coupled LDPC (SC-LDPC) codes for the coded cooperation. In particular, for the message broadcasting from the relay, we construct multi-edge-type (MET) SC-LDPC codes by repeatedly applying coset encoding. Due to the capacity-achieving property of the SC-LDPC codes, we prove that the capacity region can theoretically be achieved by the proposed MET SC-LDPC codes. Numerical results with finite node degrees are provided, which show that the achievable rates approach the boundary of the capacity region in both binary erasure channels and additive white Gaussian channels.

Keywords
wireless sensor networks, multiway relay channel, capacity region, coset encoding, multi-edge-type LDPC codes, spatially-coupled LDPC codes
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-175941 (URN)10.3390/s150715265 (DOI)000361788200022 ()26131675 (PubMedID)2-s2.0-84934765174 (Scopus ID)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), IB2015-5959
Note

QC 20151102

Available from: 2015-11-02 Created: 2015-10-26 Last updated: 2017-12-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9307-484X

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