Björn Ottersten

Björn Ottersten
University of Luxembourg · Interdisciplinary Centre for Security, Reliability and Trust

PhD Stanford Univeristy

About

1,280
Publications
267,142
Reads
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37,757
Citations
Additional affiliations
September 1986 - January 1990
Stanford University
Position
  • PhD Student
January 2009 - present
University of Luxembourg
Position
  • Director, Professor
December 1991 - present
KTH Royal Institute of Technology
Position
  • Professor (Full)

Publications

Publications (1,280)
Article
The applications of upcoming sixth-generation (6G) empowered vehicle-to-everything (V2X) communications depend heavily on large-scale data exchange with high throughput and ultra-low latency to ensure system reliability and passenger safety. However, in urban and remote areas, signals can be easily blocked by various objects. Moreover, the propagat...
Article
Full-text available
Beam-hopping (BH) technology, integral to multi-beam satellite systems, adapts beam activation to the variable communication demands of terrestrial users. The optimization of power allocation and beam illumination scheduling constitutes the core design challenge in BH systems, especially under the constraint on a limited number of simultaneously ac...
Article
Full-text available
This paper investigates the antenna selection problem in massive multiple-input multiple-out (MIMO) systems under incomplete channel state information (CSI), with a particular interest on risk-aware planning subjected to practical constraints such as transmit power budgets and quality of services (QoS). Due to a very large number of antennas, obtai...
Article
Backscatter communication (BC) technology offers sustainable solutions for next-generation Internet-of-Things (IoT) networks, where devices can transmit data by reflecting and adjusting incident radio frequency signals. In parallel to BC, deep reinforcement learning (DRL) has recently emerged as a promising tool to augment intelligence and optimize...
Preprint
Full-text available
This paper investigates joint device identification, channel estimation, and symbol detection for cooperative multi-satellite-enhanced random access, where orthogonal time-frequency space modulation with the large antenna array is utilized to combat the dynamics of the terrestrial-satellite links (TSLs). We introduce the generalized complex exponen...
Article
Full-text available
Current trends in non-geostationary orbit (NGSO) satellite communications pose the challenge of attaining high spectral efficiency with low-complexity user terminals (UTs). In this context, this letter investigates the downlink/forward transmission of linear space-time block coded (STBC) signals through multiple geographically distributed NGSO sate...
Article
Full-text available
Reconfigurable intelligent surfaces (RISs) are considered a key enabler of highly energy-efficient 6G and beyond networks. This property arises from the absence of power amplifiers in the structure, in contrast to active nodes, such as small cells and relays. However, a certain amount of power is still required for RIS operation. To improve their e...
Article
Sixth-generation (6G) non-terrestrial networks (NTNs) are advanced wireless communication systems that operate beyond traditional terrestrial networks. These networks utilize various technologies and platforms to provide flexible, enhanced connectivity and coverage. When operating at high frequency, ground user terminals require low-directional ant...
Article
Beam prediction and tracking (BPT) are key technology for high-frequency communications. Typical techniques include Kalman filtering and Gaussian process regression (GPR). However, Kalman filter requires explicit models of system dynamics, which are challenging to obtain, especially for complicated environments. In contrast, as a data-driven approa...
Article
Full-text available
With countless promising applications in various domains such as IoT and Industry 4.0, task-oriented communication design (TOCD) is getting accelerated attention from the research community. This paper presents a novel approach for designing scalable task-oriented quantization and communications in cooperative multi-agent systems (MAS). The propose...
Article
Full-text available
A cognitive fully adaptive radar (CoFAR) adapts its behavior on its own within a short period of time in response to changes in the target environment. For the CoFAR to function properly, it is critical to understand its operating environment through estimation of the clutter channel impulse response (CCIR). In general, CCIR is sparse but prior wor...
Article
This paper addresses two distinctly poised objectives, i.e., data rate and energy harvesting (EH) in Simultaneous Wireless Information and Power Transfer (SWIPT) systems with Reconfigurable Intelligent Surface (RIS) by tackling a weighted objective to maximize data rate, EH, and transmit power utilization for multi-antenna BS and multiple RIS-User...
Chapter
We introduced the concept of metacognitive radar whose aim is to impart additional confidence to the decisions of a cognitive radar. This is achieved by collating several cognitive cycles in the system for various scenarios and selecting the most appropriate one for a given situation. We discussed key elements of a metacognitive radar and its possi...
Conference Paper
Full-text available
Future generation of Wireless Communications encompasses massive connectivity of energy-starved and heavy data-driven billions of Internet-of-Things (IoT) devices. In this vein, Reconfigurable Intelligent Surface (RIS) holds great promise while providing improved performance and efficiency in terms of energy, cost and spectrum. Simultaneous Wireles...
Preprint
Full-text available
Intelligent Reconfigurable Surfaces (IRS) have emerged as an enabling technology to address the challenges of coverage, capacity, and energy efficiency beyond 5G (B5G). The classical IRS architecture with a diagonal phase shift matrix restricts the system's ability to effectively manipulate passive beamforming. To exploit its full benefits, Beyond...
Article
Low Earth Orbit (LEO) satellite communication (SatCom) has drawn particular attention recently due to its high data rate services and low round-trip latency. It has low launching and manufacturing costs than Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO) satellites. Moreover, LEO SatCom has the potential to provide global coverage wit...
Preprint
Full-text available
Sixth-generation (6G) non-terrestrial networks (NTNs) are advanced wireless communication systems that operate beyond traditional terrestrial networks. These networks utilize various technologies and platforms to provide flexible and enhanced connectivity and coverage. When operating at high frequency, ground user terminals require low-directional...
Article
Full-text available
Unmanned aerial vehicles (UAV) have emerged as a practical solution that provides on-demand services to users in areas where the terrestrial network is non-existent or temporarily unavailable, e.g., due to natural disasters or network congestion. In general, UAVs' user-serving capacity is typically constrained by their limited battery life and the...
Preprint
Full-text available
Backscatter communication (BC) technology offers sustainable solutions for next-generation Internet-of-Things (IoT) networks, where devices can transmit data by reflecting and adjusting incident radio frequency signals. In parallel to BC, deep reinforcement learning (DRL) has recently emerged as a promising tool to augment intelligence and optimize...
Preprint
This paper studies the potential of RIS-integrated NTNs to revolutionize the next-generation connectivity. First, it discusses the fundamentals of RIS technology. Secondly, it delves into reporting the recent advances in RIS-enabled NTNs. Subsequently, it presents a novel framework based on the current state-of-the-art for low earth orbit satellite...
Article
Reflecting intelligent surfaces (RIS) has gained significant attention due to its high energy and spectral efficiency in next-generation wireless networks. By using low-cost passive reflecting elements, RIS can smartly reconfigure the signal propagation to extend the wireless communication coverage. On the other hand, non-orthogonal multiple access...
Article
Full-text available
Fifth-generation (5G) and beyond communication systems offer new functionalities and significant performance improvements but that comes at the cost of tougher energy requirements on user devices. Addressing this issue while reducing the environmental impact of the substantial increase in energy consumption can be achieved through energy-neutral sy...
Preprint
Full-text available
Reconfigurable intelligent surfaces (RISs) are considered to be a key enabler of highly energy-efficient 6G and beyond networks. This property arises from the absence of power amplifiers in the structure, in contrast to active nodes, such as small cells and relays. However, still an amount of power is required for their operation. To improve their...
Preprint
Full-text available
The paradigm of joint communications and sensing (JCAS) envisions a revolutionary integration of communication and radar functionalities within a unified hardware platform. This novel concept not only opens up unprecedented possibilities, but also presents unique challenges. Its success is highly dependent on efficient full-duplex (FD) operation, w...
Preprint
Full-text available
p>This paper considers RIS enhanced D2D communications underlaying unmanned aerial vehicle (UAV) networks with non-orthogonal multiple access (NOMA). The objective is to maximize the sum rate of NOMA D2D communications by optimizing the power budget of D2D transmitter, NOMA power allocation coefficients of D2D receivers and passive beamforming of R...
Preprint
Full-text available
p>This paper considers RIS enhanced D2D communications underlaying unmanned aerial vehicle (UAV) networks with non-orthogonal multiple access (NOMA). The objective is to maximize the sum rate of NOMA D2D communications by optimizing the power budget of D2D transmitter, NOMA power allocation coefficients of D2D receivers and passive beamforming of R...
Preprint
Full-text available
p>Intelligent reconfigurable surfaces (RIS) have emerged as one of the most promising and cost-effective technologies due to their high energy efficiency, extended wireless coverage, enhanced signal strength, and interference mitigation capability. This paper provides a new framework of cognitive radio-based integrated terrestrial non-terrestrial n...
Preprint
Full-text available
This paper investigates joint device identification, channel estimation, and signal detection for LEO satellite-enabled grant-free random access, where a multiple-input multipleoutput (MIMO) system with orthogonal time-frequency space modulation (OTFS) is utilized to combat the dynamics of the terrestrial-satellite link (TSL). We divide the receive...
Preprint
Full-text available
In this paper, we tackle the problem of joint symbol level precoding (SLP) and reconfigurable intelligent surface (RIS) phase shift design with constellation rotation in the finite block length regime. We aim to increase energy efficiency by minimizing the total transmit power while satisfying the quality of service constraints. The total power con...
Preprint
Full-text available
Intelligent reconfigurable surfaces (RIS) have emerged as one of the most promising and cost-effective technologies due to their high energy efficiency, extended wireless coverage, enhanced signal strength, and interference mitigation capability. This paper provides a new framework of cognitive radio-based integrated terrestrial non-terrestrial net...
Preprint
Full-text available
p>Intelligent reconfigurable surfaces (RIS) have emerged as one of the most promising and cost-effective technologies due to their high energy efficiency, extended wireless coverage, enhanced signal strength, and interference mitigation capability. This paper provides a new framework of cognitive radio-based integrated terrestrial non-terrestrial n...
Chapter
The fifth-generation and beyond (B5G) wireless networks aim to achieve ultra-high data transmission rates, reduce power consumption, and improved spectral efficiency. In this context, millimeter-wave (mmWave) and terahertz (THz) bands are key enablers to meeting B5G requirements. These bands offer ultrawide bandwidths and require large antenna arra...
Preprint
Full-text available
The space communications industry is challenged to develop a technology that can deliver broadband services to user terminals equipped with miniature antennas, such as handheld devices. One potential solution to establish links with ground users is the deployment of massive antennas in one single spacecraft. However, this is not cost-effective. Ali...
Preprint
Full-text available
This paper proposes an energy-efficient RIS-assisted downlink NOMA communication for LEO satellite networks. The proposed framework simultaneously optimizes the transmit power of ground terminals of the LEO satellite and the passive beamforming of RIS while ensuring the quality of services. Due to the nature of the considered system and optimizatio...
Conference Paper
Full-text available
Next-generation multi-spot beam satellite systems open a new way to design low earth orbit (LEO) satellite communication systems with full flexibility in managing bandwidth, transmit power, and spot beam coverage, enabling the adoption of spatial multiplexing techniques to meet the unprecedented demand for future mobile traffic. However, convention...
Article
Low earth orbit (LEO) satellite constellation-enabled communication networks are expected to be an important part of many Internet of Things (IoT) deployments due to their unique advantage of providing seamless global coverage. In this paper, we investigate the random access problem in massive multiple-input multiple-output-based LEO satellite syst...
Article
Full-text available
In polarimetric radars, corresponding to the polarized antennas, exploiting waveform diversity along the polarization dimension becomes accessible. In this paper, we aim to maximize the signal-to-interference plus noise ratio (SINR) of a polari-metric radar by optimizing the transmit polarimetric waveform, the power allocation on its horizontal and...
Preprint
Full-text available
With countless promising applications in various domains such as IoT and industry 4.0, task-oriented communication design (TOCD) is getting accelerated attention from the research community. This paper presents a novel approach for designing scalable task-oriented quantization and communications in cooperative multi-agent systems (MAS). The propose...
Preprint
Full-text available
Unmanned aerial vehicles (UAV) have emerged as a practical solution that provides on-demand services to users in areas where the terrestrial network is non-existent or temporarily unavailable, e.g., due to natural disasters or network congestion. In general, UAVs' user-serving capacity is typically constrained by their limited battery life and the...
Preprint
Full-text available
This work considers the orthogonal frequency division multiple access (OFDMA) technology that enables multiple unmanned aerial vehicles (multi-UAV) communication systems to provide on-demand services. The main aim of this work is to derive the optimal allocation of radio resources, 3D placement of UAVs, and user association matrices. To achieve the...
Article
Full-text available
This paper introduces the concept of energy efficiency (EE) in the uplink with the capability of multi-connectivity (MC) in a multi-orbit non-terrestrial network (NTN), where user terminals (UTs) can be simultaneously served by more than one satellite to achieve higher peak throughput at reduced energy consumption. This concept also considers the s...
Preprint
Low earth orbit (LEO) satellite constellation-enabled communication networks are expected to be an important part of many Internet of Things (IoT) deployments due to their unique advantage of providing seamless global coverage. In this paper, we investigate the random access problem in massive multiple-input multiple-output-based LEO satellite syst...
Preprint
Full-text available
Reflecting intelligent surfaces (RIS) has gained significant attention due to its high energy and spectral efficiency in next-generation wireless networks. By using low-cost passive reflecting elements, RIS can smartly reconfigure the signal propagation to extend the wireless communication coverage. On the other hand, non-orthogonal multiple access...
Preprint
Full-text available
Reconfigurable Intelligent surfaces (RIS) have the potential to significantly improve the performance of future 6G LEO satellite networks. In particular, RIS can improve the signal quality of ground terminal, reduce power consumption of satellite and increase spectral efficiency of overall network. This paper proposes an energy-efficient RIS-enable...
Preprint
Full-text available
We consider a task-effective quantization problem that arises when multiple agents are controlled via a centralized controller (CC). While agents have to communicate their observations to the CC for decision-making, the bit-budgeted communications of agent-CC links may limit the task-effectiveness of the system which is measured by the system's ave...
Article
Full-text available
High-Throughput Satellite (HTS) systems with digital payload technology have been identified as a key enabler to support 5G/6G high-data connectivity with wider coverage area. The satellite community has extensively explored resource allocation methods to achieve this target. Typically, these methods do not consider the intrinsic architecture of th...
Article
With the blooming of Internet-of-Things (IoT), we are witnessing an explosion in the number of IoT terminals, triggering an unprecedented demand for ubiquitous wireless access globally. In this context, the emerging low-Earth-orbit satellites (LEO-SATs) have been regarded as a promising enabler to complement terrestrial wireless networks in providi...