Publications
283 results found
Joudeh H, Clerckx B, 2019, On the optimality of treating inter-cell interference as noise in uplink cellular networks, IEEE Transactions on Information Theory, Vol: 65, Pages: 7208-7232, ISSN: 0018-9448
In this paper, we explore the information-theoretic optimality of treating interference as noise (TIN) in cellular networks. We focus on uplink scenarios modeled by the Gaussian interfering multiple access channel (IMAC), comprising K mutually interfering multiple access channels (MACs), each formed by an arbitrary number of transmitters communicating independent messages to one receiver. We define TIN for this setting as a scheme in which each MAC (or cell) performs a power-controlled version of its capacity-achieving strategy, with Gaussian codebooks and successive decoding, while treating interference from all other MACs (i.e. inter-cell interference) as noise. We characterize the generalized degrees-of-freedom (GDoF) region achieved through the proposed TIN scheme, and then identify conditions under which this achievable region is convex without the need for time-sharing. We then tighten these convexity conditions and identify a regime in which the proposed TIN scheme achieves the entire GDoF region of the IMAC and is within a constant gap of the entire capacity region.
Zhang J, Clerckx B, Ge J, et al., 2019, Cooperative Rate Splitting for MISO Broadcast Channel With User Relaying, and Performance Benefits Over Cooperative NOMA, IEEE SIGNAL PROCESSING LETTERS, Vol: 26, Pages: 1678-1682, ISSN: 1070-9908
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- Citations: 41
Varasteh M, Rassouli B, Clerckx B, 2019, SWIPT Signaling Over Frequency-Selective Channels With a Nonlinear Energy Harvester: Non-Zero Mean and Asymmetric Inputs, IEEE TRANSACTIONS ON COMMUNICATIONS, Vol: 67, Pages: 7195-7210, ISSN: 0090-6778
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- Citations: 5
Piovano E, Joudeh H, Clerckx B, 2019, Generalized degrees of freedom of the symmetric cache-aided MISO broadcast channel with partial CSIT, IEEE Transactions on Information Theory, Vol: 65, Pages: 5799-5815, ISSN: 0018-9448
We consider the cache-aided MISO broadcast channel (BC) in which a multi-antenna transmitter serves K singleantenna receivers, each equipped with a cache memory. The transmitter has access to partial knowledge of the channel state information. For a symmetric setting, in terms of channel strength levels, partial channel knowledge levels and cache sizes, we characterize the generalized degrees of freedom (GDoF) up to a constant multiplicative factor. The achievability scheme exploits the interplay between spatial multiplexing gains and codedmulticasting gain. On the other hand, a cut-set-based argument in conjunction with a GDoF outer bound for a parallel MISO BC under channel uncertainty are used for the converse. We further show that the characterized order-optimal GDoF is also attained in a decentralized setting, where no coordination is required for content placement in the caches.
Mao Y, Clerckx B, Li VOK, 2019, Rate-splitting multiple access for coordinated multi-point joint transmission
As a promising downlink multiple access scheme, Rate-Splitting Multiple Access (RSMA) has been shown to achieve superior spectral and energy efficiencies compared with SpaceDivision Multiple Access (SDMA) and Non-Orthogonal Multiple Access (NOMA) in downlink single-cell systems. By relying on linearly precoded rate-splitting at the transmitter and successive interference cancellation at the receivers, RSMA has the capability of partially decoding the interference and partially treating the interference as noise, and therefore copes with a wide range of user deployments and network loads. In this work, we further study RSMA in downlink Coordinated Multi-Point (CoMP) Joint Transmission (JT) networks by investigating the optimal beamformer design to maximize the Weighted Sum-Rate (WSR) of all users subject to individual Quality of Service (QoS) rate constraints and per base station power constraints. Numerical results show that, in CoMP JT, RSMA achieves significant WSR improvement over SDMA and NOMA in a wide range of inter-user and inter-cell channel strength disparities. Specifically, SDMA (resp. NOMA) is more suited to deployments with little (resp. large) inter-user channel strength disparity and large (resp. little) inter-cell channel disparity, while RSMA is suited to any deployment. We conclude that RSMA provides rate, robustness and QoS enhancements over SDMA and NOMA in CoMP JT networks.
Clerckx B, Zhang R, Schober R, et al., 2019, Guest Editorial Wireless Transmission of Information and Power-Part II, IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, Vol: 37, Pages: 249-252, ISSN: 0733-8716
Clerckx B, Zhang R, Schober R, et al., 2019, Fundamentals of wireless information and power transfer: From RF energy harvester models to signal and system designs, IEEE Journal on Selected Areas in Communications, Vol: 37, Pages: 4-33, ISSN: 0733-8716
Radio waves carry both energy and information simultaneously. Nevertheless, radio-frequency (RF) transmissions of these quantities have traditionally been treated separately. Currently, the community is experiencing a paradigm shift in wireless network design, namely, unifying wireless transmission of information and power so as to make the best use of the RF spectrum and radiation as well as the network infrastructure for the dual purpose of communicating and energizing. In this paper, we review and discuss recent progress in laying the foundations of the envisioned dual purpose networks by establishing a signal theory and design for wireless information and power transmission (WIPT) and identifying the fundamental tradeoff between conveying information and power wirelessly. We start with an overview of WIPT challenges and technologies, namely, simultaneous WIPT (SWIPT), wirelessly powered communication networks (WPCNs), and wirelessly powered backscatter communication (WPBC). We then characterize energy harvesters and show how WIPT signal and system designs crucially revolve around the underlying energy harvester model. To that end, we highlight three different energy harvester models, namely, one linear model and two nonlinear models, and show how WIPT designs differ for each of them in single-user and multi-user deployments. Topics discussed include rate-energy region characterization, transmitter and receiver architectures, waveform design, modulation, beamforming and input distribution optimizations, resource allocation, and RF spectrum use. We discuss and check the validity of the different energy harvester models and the resulting signal theory and design based on circuit simulations, prototyping, and experimentation. We also point out numerous directions that are promising for future research.
Zawawi ZB, Huang Y, Clerckx B, 2019, Multiuser Wirelessly Powered Backscatter Communications: Nonlinearity, Waveform Design, and SINR-Energy Tradeoff, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, Vol: 18, Pages: 241-253, ISSN: 1536-1276
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- Citations: 33
Clerckx B, Zhang R, Schober R, et al., 2019, Wireless Transmission of Information and Power-Part I, IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, Vol: 37, Pages: 1-3, ISSN: 0733-8716
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- Citations: 7
Varasteh M, Hoydis J, Clerckx B, 2019, Learning Modulation Design for SWIPT with Nonlinear Energy Harvester: Large and Small Signal Power Regimes, 20th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Publisher: IEEE, ISSN: 2325-3789
Ouda MH, Mitcheson P, Clerckx B, 2019, Robust Wireless Power Receiver for Multi-Tone Waveforms, 49th European Microwave Conference (EuMC), Publisher: IEEE, Pages: 101-104, ISSN: 2325-0305
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- Citations: 5
Mao Y, Clerckx B, Li VOK, 2019, Rate-Splitting for Multi-User Multi-Antenna Wireless Information and Power Transfer, 20th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Publisher: IEEE, ISSN: 2325-3789
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- Citations: 44
Varasteh M, Piovano E, Clerckx B, 2019, A LEARNING APPROACH TO WIRELESS INFORMATION AND POWER TRANSFER SIGNAL AND SYSTEM DESIGN, 44th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Publisher: IEEE, Pages: 4534-4538, ISSN: 1520-6149
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- Citations: 13
Mao Y, Clerckx B, Li VOK, 2019, Rate-Splitting Multiple Access for Coordinated Multi-Point Joint Transmission, IEEE International Conference on Communications (IEEE ICC), Publisher: IEEE, ISSN: 2164-7038
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- Citations: 1
Joudeh H, Clerckx B, 2019, DoF Region of the MISO BC with Partial CSIT: Proof by Inductive Fourier-Motzkin Elimination, Publisher: IEEE
Joudeh H, Yi X, Clerckx B, 2019, On Multi-Cell Uplink-Downlink Duality with Treating Inter-Cell Interference as Noise, Publisher: IEEE
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- Citations: 2
Kim J, Clerckx B, Mitcheson PD, 2019, Experimental Analysis of Harvested Energy and Throughput Trade-off in a Realistic SWIPT System, 2019 IEEE MTT-S WIRELESS POWER TRANSFER CONFERENCE (WPTC) / IEEE PELS WORKSHOP ON EMERGING TECHNOLOGIES: WIRELESS POWER (WOW) / WIRELESS POWER WEEK (WPW 2019), Pages: 1-5, ISSN: 2474-0225
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- Citations: 22
Clerckx B, Kim J, 2018, On the beneficial roles of fading and transmit diversity in wireless power transfer with nonlinear energy harvesting, IEEE Transactions on Wireless Communications, Vol: 17, Pages: 7731-7743, ISSN: 1536-1276
We study the effect of channel fading in WirelessPower Transfer (WPT) and show that fading enhances the RF-to-DC conversion efficiency of nonlinear RF energy harvesters.We then develop a new form of signal design for WPT, denoted asTransmit Diversity, that relies on multiple dumb antennas at thetransmitter to induce fast fluctuations of the wireless channel.Those fluctuations boost the RF-to-DC conversion efficiencythanks to the energy harvester nonlinearity. In contrast with(energy) beamforming, Transmit Diversity does not rely onChannel State Information at the Transmitter (CSIT) and doesnot increase the average power at the energy harvester input,though it still enhances the overall end-to-end power transferefficiency. Transmit Diversity is also combined with recentlydeveloped (energy) waveform and modulation to provide furtherenhancements. The efficacy of the scheme is analyzed usingphysics-based and curve fitting-based nonlinear models of the en-ergy harvester and demonstrated using circuit simulations, pro-totyping and experimentation. Measurements with two transmitantennas reveal gains of 50% in harvested DC power over a singletransmit antenna setup. The work (again) highlights the crucialrole played by the harvester nonlinearity and demonstrates thatmultiple transmit antennas can be beneficial to WPT even in theabsence of CSIT.
Mao Y, Clerckx B, Li VOK, 2018, Energy Efficiency of Rate-Splitting Multiple Access, and Performance Benefits over SDMA and NOMA, ISSN: 2154-0217
Rate-Splitting Multiple Access (RSMA) is a general and powerful multiple access framework for downlink multi- Antenna systems, and contains Space-Division Multiple Access (SDMA) and Non-Orthogonal Multiple Access (NOMA) as spe- cial cases. RSMA relies on linearly precoded rate-splitting with Successive Interference Cancellation (SIC) to decode part of the interference and treat the remaining part of the interference as noise. Recently, RSMA has been shown to outperform both SDMA and NOMA rate-wise in a wide range of network loads (underloaded and overloaded regimes) and user deployments (with a diversity of channel directions, channel strengths and qualities of channel state information at the transmitter). Moreover, RSMA was shown to provide spectral efficiency and QoS enhancements over NOMA at a lower computational complexity for the transmit scheduler and the receivers. In this paper, we build upon those results and investigate the energy efficiency of RSMA compared to SDMA and NOMA. Considering a multiple-input single-output broadcast channel, we show that RSMA is more energy-efficient than SDMA and NOMA in a wide range of user deployments (with a diversity of channel directions and channel strengths). We conclude that RSMA is more spectrally and energy-efficient than SDMA and NOMA.
Clerckx B, Costanzo A, Georgiadis A, et al., 2018, Toward 1G Mobile Power Networks, IEEE MICROWAVE MAGAZINE, Vol: 19, Pages: 69-82, ISSN: 1527-3342
Joudeh H, Clerckx B, 2018, On the Optimality of Treating Interference as Noise for Interfering Multiple Access Channels, IEEE International Symposium on Information Theory (ISIT), Pages: 1530-1534, ISSN: 2157-8117
Mao Y, Clerckx B, Li VOK, 2018, Rate-splitting multiple access for downlink communication systems: bridging, generalizing and outperforming SDMA and NOMA, EURASIP Journal on Wireless Communications and Networking, Vol: 2018, ISSN: 1687-1472
Space-division multiple access (SDMA) utilizes linear precoding to separate users in the spatial domain and relies on fully treating any residual multi-user interference as noise. Non-orthogonal multiple access (NOMA) uses linearly precoded superposition coding with successive interference cancellation (SIC) to superpose users in the power domain and relies on user grouping and ordering to enforce some users to fully decode and cancel interference created by other users.In this paper, we argue that to efficiently cope with the high throughput, heterogeneity of quality of service (QoS), and massive connectivity requirements of future multi-antenna wireless networks, multiple access design needs to depart from those two extreme interference management strategies, namely fully treat interference as noise (as in SDMA) and fully decode interference (as in NOMA).Considering a multiple-input single-output broadcast channel, we develop a novel multiple access framework, called rate-splitting multiple access (RSMA). RSMA is a more general and more powerful multiple access for downlink multi-antenna systems that contains SDMA and NOMA as special cases. RSMA relies on linearly precoded rate-splitting with SIC to decode part of the interference and treat the remaining part of the interference as noise. This capability of RSMA to partially decode interference and partially treat interference as noise enables to softly bridge the two extremes of fully decoding interference and treating interference as noise and provides room for rate and QoS enhancements and complexity reduction.The three multiple access schemes are compared, and extensive numerical results show that RSMA provides a smooth transition between SDMA and NOMA and outperforms them both in a wide range of network loads (underloaded and overloaded regimes) and user deployments (with a diversity of channel directions, channel strengths, and qualities of channel state information at the transmitter). Moreover, RSMA provid
Ouda MHI, Mitcheson P, Clerckx B, 2018, Optimal Operation of Multi-Tone Waveforms inLow RF-Power Receivers, IEEE MTT-S Wireless Power Transfer Conference
Park J, Clerckx B, Song C, et al., 2018, An Analysis of the Optimum Node Density for Simultaneous Wireless Information and Power Transfer in Ad Hoc Networks, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol: 67, Pages: 2713-2726, ISSN: 0018-9545
Clerckx B, 2018, Wireless information and power transfer: nonlinearity, waveform design, and rate-energy tradeoff, IEEE Transactions on Signal Processing, Vol: 66, Pages: 847-862, ISSN: 1053-587X
The design of wireless information and power transfer (WIPT) has so far relied on an oversimplified and inaccurate linear model of the energy harvester. In this paper, we depart from this linear model and design WIPT considering the rectifier nonlinearity. We develop a tractable model of the rectifier nonlinearity that is flexible enough to cope with general multicarrier modulated input waveforms. Leveraging that model, we motivate and introduce a novel WIPT architecture relying on the superposition of multicarrier unmodulated and modulated waveforms at the transmitter. The superposed WIPT waveforms are optimized as a function of the channel state information so as to characterize the rate-energy region of the whole system. Analysis and numerical results illustrate the performance of the derived waveforms and WIPT architecture and highlight that nonlinearity radically changes the design of WIPT. We make key and refreshing observations. First, analysis (confirmed by circuit simulations) shows that modulated and unmodulated waveforms are not equally suitable for wireless power delivery, namely, modulation being beneficial in single-carrier transmissions but detrimental in multicarrier transmissions. Second, a multicarrier unmodulated waveform (superposed to a multicarrier modulated waveform) is useful to enlarge the rate-energy region of WIPT. Third, a combination of power splitting and time sharing is in general the best strategy. Fourth, a nonzero mean Gaussian input distribution outperforms the conventional capacity-achieving zero-mean Gaussian input distribution in multicarrier transmissions. Fifth, the rectifier nonlinearity is beneficial to system performance and is essential to efficient WIPT design.
Varasteh M, Rassouli B, Clerckx B, 2018, Wireless Information and Power Transfer over an AWGN channel: Nonlinearity and Asymmetric Gaussian Signaling, 2017 IEEE Information Theory Workshop (ITW), Publisher: IEEE, Pages: 181-183, ISSN: 2475-420X
Xu J, Clerckx B, Ding Z, et al., 2018, IEEE ACCESS Special Section Editorial: Energy Efficient Wireless Communications With Energy Harvesting and Wireless Power Transfer, IEEE ACCESS, Vol: 6, Pages: 72041-72045, ISSN: 2169-3536
Mao Y, Clerckx B, Li VOK, 2018, Rate-Splitting for Multi-Antenna Non-Orthogonal Unicast and Multicast Transmission, IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Publisher: IEEE, Pages: 955-959, ISSN: 2325-3789
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- Citations: 11
Bayguzina E, Clerckx B, 2018, Modulation Design for Wireless Information and Power Transfer with Nonlinear Energy Harvester Modeling, 19th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Publisher: IEEE, Pages: 291-295, ISSN: 2325-3789
Piovano E, Joudeh H, Clerckx B, 2018, Robust Cache-Aided Interference Management Under Full Transmitter Cooperation, IEEE International Symposium on Information Theory (ISIT), Publisher: IEEE, Pages: 1540-1544
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- Citations: 3
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