1.
Yu, Quantao; Mishra, Deepak; Wang, Hua; He, Dongxuan; Yuan, Jinhong; Matthaiou, Michail
Toward LoRa-Based LEO Satellite IoT: A Stochastic Geometry Perspective Journal Article
In: IEEE Internet of Things Journal, vol. 12, no. 15, pp. 30725–30738, 2025, ISSN: 2327-4662.
Abstract | Links | BibTeX | Tags: Access probability, Analytical models, Interference, Internet of Things, Long-Range (LoRa), LoRa, Low earth orbit satellites, Performance analysis, Rayleigh channels, Satellite broadcasting, satellite Internet of Things (IoT), Satellites, stochastic geometry (SG), Uplink
@article{yu_toward_2025,
title = {Toward LoRa-Based LEO Satellite IoT: A Stochastic Geometry Perspective},
author = {Quantao Yu and Deepak Mishra and Hua Wang and Dongxuan He and Jinhong Yuan and Michail Matthaiou},
url = {https://ieeexplore.ieee.org/document/11007561},
doi = {10.1109/JIOT.2025.3571928},
issn = {2327-4662},
year = {2025},
date = {2025-08-01},
urldate = {2025-10-08},
journal = {IEEE Internet of Things Journal},
volume = {12},
number = {15},
pages = {30725–30738},
abstract = {Recently, Long-Range (LoRa)-based low-Earth orbit (LEO) satellite Internet of Things (IoT) has garnered growing interest from both academia and industry, since it can guarantee pervasive connectivity in an energy-efficient and cost-effective manner. In this article, we provide a novel spherical stochastic geometry (SG)-based analytical framework for characterizing the uplink access probability of LoRa-based LEO satellite IoT system. Specifically, multiple classes of LoRa end-devices (EDs) are taken into consideration, where each class of LoRa EDs is modeled by an independent Poisson point process (PPP). Both the channel characteristics of the satellite-to-Earth communications and the unique features of the LoRa network are considered to derive closed-form analytical expressions for the uplink access probability of such a new paradigm. Moreover, the nontrivial impact of the spreading factor, the ED’s density, the orbit altitude, and the satellite effective beamwidth on the system performance is thoroughly investigated. Extensive numerical simulations are conducted, which not only validate the accuracy of our theoretical analysis but also provide useful insights into the practical design and implementation of LoRa-based LEO satellite IoT system.},
keywords = {Access probability, Analytical models, Interference, Internet of Things, Long-Range (LoRa), LoRa, Low earth orbit satellites, Performance analysis, Rayleigh channels, Satellite broadcasting, satellite Internet of Things (IoT), Satellites, stochastic geometry (SG), Uplink},
pubstate = {published},
tppubtype = {article}
}
Recently, Long-Range (LoRa)-based low-Earth orbit (LEO) satellite Internet of Things (IoT) has garnered growing interest from both academia and industry, since it can guarantee pervasive connectivity in an energy-efficient and cost-effective manner. In this article, we provide a novel spherical stochastic geometry (SG)-based analytical framework for characterizing the uplink access probability of LoRa-based LEO satellite IoT system. Specifically, multiple classes of LoRa end-devices (EDs) are taken into consideration, where each class of LoRa EDs is modeled by an independent Poisson point process (PPP). Both the channel characteristics of the satellite-to-Earth communications and the unique features of the LoRa network are considered to derive closed-form analytical expressions for the uplink access probability of such a new paradigm. Moreover, the nontrivial impact of the spreading factor, the ED’s density, the orbit altitude, and the satellite effective beamwidth on the system performance is thoroughly investigated. Extensive numerical simulations are conducted, which not only validate the accuracy of our theoretical analysis but also provide useful insights into the practical design and implementation of LoRa-based LEO satellite IoT system.
2.
Meng, Kaitao; Masouros, Christos; Wong, Kai-Kit; Petropulu, Athina P.; Hanzo, Lajos
Integrated Sensing and Communication Meets Smart Propagation Engineering: Opportunities and Challenges Journal Article
In: IEEE Network, vol. 39, no. 2, pp. 278–285, 2025, ISSN: 1558-156X.
Abstract | Links | BibTeX | Tags: Antennas, Channel estimation, fluid antennas, Fluids, Integrated sensing and communication, intelligent surfaces, Interference, Mobile antennas, Radio transmitters, smart propagation engineering, Trajectory, Transmitting antennas, Wireless communication
@article{meng_integrated_2025,
title = {Integrated Sensing and Communication Meets Smart Propagation Engineering: Opportunities and Challenges},
author = {Kaitao Meng and Christos Masouros and Kai-Kit Wong and Athina P. Petropulu and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10833779},
doi = {10.1109/MNET.2025.3527130},
issn = {1558-156X},
year = {2025},
date = {2025-03-01},
urldate = {2025-10-08},
journal = {IEEE Network},
volume = {39},
number = {2},
pages = {278–285},
abstract = {Both smart propagation engineering as well as integrated sensing and communication (ISAC) constitute promising candidates for next-generation (NG) mobile networks. We provide a synergistic view of these technologies, and explore their mutual benefits. First, moving beyond just intelligent surfaces, we provide a holistic view of the engineering aspects of smart propagation environments. By delving into the fundamental characteristics of intelligent surfaces, fluid antennas, and unmanned aerial vehicles, we reveal that more efficient control of the pathloss and fading can be achieved, thus facilitating intrinsic integration and mutual assistance between sensing and communication functionalities. In turn, with the exploitation of the sensing capabilities of ISAC to orchestrate the efficient configuration of radio environments, both the computational effort and signaling overheads can be reduced. We present indicative simulation results, which verify that cooperative smart propagation environment design significantly enhances the ISAC performance. Finally, some promising directions are outlined for combining ISAC with smart propagation engineering.},
keywords = {Antennas, Channel estimation, fluid antennas, Fluids, Integrated sensing and communication, intelligent surfaces, Interference, Mobile antennas, Radio transmitters, smart propagation engineering, Trajectory, Transmitting antennas, Wireless communication},
pubstate = {published},
tppubtype = {article}
}
Both smart propagation engineering as well as integrated sensing and communication (ISAC) constitute promising candidates for next-generation (NG) mobile networks. We provide a synergistic view of these technologies, and explore their mutual benefits. First, moving beyond just intelligent surfaces, we provide a holistic view of the engineering aspects of smart propagation environments. By delving into the fundamental characteristics of intelligent surfaces, fluid antennas, and unmanned aerial vehicles, we reveal that more efficient control of the pathloss and fading can be achieved, thus facilitating intrinsic integration and mutual assistance between sensing and communication functionalities. In turn, with the exploitation of the sensing capabilities of ISAC to orchestrate the efficient configuration of radio environments, both the computational effort and signaling overheads can be reduced. We present indicative simulation results, which verify that cooperative smart propagation environment design significantly enhances the ISAC performance. Finally, some promising directions are outlined for combining ISAC with smart propagation engineering.
3.
Singh, Jitendra; Srivastava, Suraj; Yadav, Surya P.; Jagannatham, Aditya K.; Hanzo, Lajos
Joint Hybrid Transceiver and Reflection Matrix Design for RIS-Aided mmWave MIMO Cognitive Radio Systems Journal Article
In: IEEE Transactions on Cognitive Communications and Networking, vol. 11, no. 1, pp. 391–407, 2025, ISSN: 2332-7731.
Abstract | Links | BibTeX | Tags: Array signal processing, cognitive radio, Downlink, hybrid beamforming, Interference, Millimeter wave communication, MIMO communication, mmWave, Quality of service, Radio frequency, Riemannian conjugate gradient, RIS
@article{singh_joint_2025,
title = {Joint Hybrid Transceiver and Reflection Matrix Design for RIS-Aided mmWave MIMO Cognitive Radio Systems},
author = {Jitendra Singh and Suraj Srivastava and Surya P. Yadav and Aditya K. Jagannatham and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10561503},
doi = {10.1109/TCCN.2024.3415620},
issn = {2332-7731},
year = {2025},
date = {2025-02-01},
urldate = {2025-10-08},
journal = {IEEE Transactions on Cognitive Communications and Networking},
volume = {11},
number = {1},
pages = {391–407},
abstract = {In this work, a reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) multiple-input multiple-output (MIMO) cognitive radio (CR) downlink operating in the underlay mode is investigated. The cognitive base station (CBS) communicates with multiple secondary users (SUs), each having multiple RF chains in the presence of a primary user (PU). We conceive a joint hybrid transmit precoder (TPC), receiver combiner (RC), and RIS reflection matrix (RM) design, which maximizes the sum spectral efficiency (SE) of the secondary system while maintaining the interference induced at the PU below a specified threshold. To this end, we formulate the sum-SE maximization problem considering the total transmit power (TP), the interference power (IP), and the non-convex unity modulus constraints of the RF TPC, RF RC, and RM. To solve this highly non-convex problem, we propose a two-stage hybrid transceiver design in conjunction with a novel block coordinate descent (BCD)-successive Riemannian conjugate gradient (SRCG) algorithm. We initially decompose the RF TPC, RC, and RM optimization problem into a series of sub-problems and subsequently design pairs of RF TPC and RC vectors, followed by successively optimizing the elements of the RM using the iterative BCD-SRCG algorithm. Furthermore, based on the effective baseband (BB) channel, the BB TPC and BB RC are designed using the proposed direct singular value decomposition (D-SVD) and projection based SVD (P-SVD) methods. Subsequently, the proportional water-filling solution is proposed for optimizing the power, which maximizes the weighted sum-SE of the system. Finally, simulation results are provided to compare our proposed schemes to several benchmarks and quantify the impact of other parameters on the sum-SE of the system.},
keywords = {Array signal processing, cognitive radio, Downlink, hybrid beamforming, Interference, Millimeter wave communication, MIMO communication, mmWave, Quality of service, Radio frequency, Riemannian conjugate gradient, RIS},
pubstate = {published},
tppubtype = {article}
}
In this work, a reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) multiple-input multiple-output (MIMO) cognitive radio (CR) downlink operating in the underlay mode is investigated. The cognitive base station (CBS) communicates with multiple secondary users (SUs), each having multiple RF chains in the presence of a primary user (PU). We conceive a joint hybrid transmit precoder (TPC), receiver combiner (RC), and RIS reflection matrix (RM) design, which maximizes the sum spectral efficiency (SE) of the secondary system while maintaining the interference induced at the PU below a specified threshold. To this end, we formulate the sum-SE maximization problem considering the total transmit power (TP), the interference power (IP), and the non-convex unity modulus constraints of the RF TPC, RF RC, and RM. To solve this highly non-convex problem, we propose a two-stage hybrid transceiver design in conjunction with a novel block coordinate descent (BCD)-successive Riemannian conjugate gradient (SRCG) algorithm. We initially decompose the RF TPC, RC, and RM optimization problem into a series of sub-problems and subsequently design pairs of RF TPC and RC vectors, followed by successively optimizing the elements of the RM using the iterative BCD-SRCG algorithm. Furthermore, based on the effective baseband (BB) channel, the BB TPC and BB RC are designed using the proposed direct singular value decomposition (D-SVD) and projection based SVD (P-SVD) methods. Subsequently, the proportional water-filling solution is proposed for optimizing the power, which maximizes the weighted sum-SE of the system. Finally, simulation results are provided to compare our proposed schemes to several benchmarks and quantify the impact of other parameters on the sum-SE of the system.
4.
Liu, Yi; Ali, Wajahat; Chen, Rui; Bamiedakis, Nikolaos; White, Ian H.; Haas, Harald; Crisp, Michael; Penty, Richard V.
A Scalable VCSEL-Array Optical Wireless Transmitter With Experimental Multi-Beam Prototype Journal Article
In: Journal of Lightwave Technology, pp. 1–7, 2025, ISSN: 1558-2213.
Abstract | Links | BibTeX | Tags: Arrays, Free-space optical communication, Interference, Lenses, LRDC, Microoptics, Optical arrays, optical communication equipment, Optical fibers, Optical receivers, Optical transmitters, Vertical cavity surface emitting lasers, verticalcavity surface-emitting lasers, Wireless communication
@article{liu_scalable_2025,
title = {A Scalable VCSEL-Array Optical Wireless Transmitter With Experimental Multi-Beam Prototype},
author = {Yi Liu and Wajahat Ali and Rui Chen and Nikolaos Bamiedakis and Ian H. White and Harald Haas and Michael Crisp and Richard V. Penty},
url = {https://ieeexplore.ieee.org/document/11189981},
doi = {10.1109/JLT.2025.3617131},
issn = {1558-2213},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-17},
journal = {Journal of Lightwave Technology},
pages = {1–7},
abstract = {A 5×5 VCSEL array-based optical wireless communication multi-beam transmitter is designed and simulated. Each element of the array addresses a separate spatial attocell. A microlens-array based homogenizer achieves uniform coverage at the receiver plane from each multi-mode VCSEL output. 1 m2 total coverage is achieved with each attocell covering an area of 400 cm2 at a range of 3 m. For a proof-of-concept demonstration a 1×3 channel VCSEL array-based transmitter prototype is experimentally tested. The performance is verified by demonstrating three channels achieving ∼ 0.12 mW/m2 uniform power with negligible optical interference to adjacent attocells (<-14 dB). With a simple receiver design using low cost, off-the-shelf components, each channel of the transmitter achieves ∼10 Gb/s throughput using OFDM within 7 cm lateral range and > 4 Gb/s within 12 cm lateral range at 3 m. The transmitter meets eye-safety restrictions and could be scaled to 250 Gb/s aggregate data rate by employing all 25 VCSELs with independent OFDM modulation.},
keywords = {Arrays, Free-space optical communication, Interference, Lenses, LRDC, Microoptics, Optical arrays, optical communication equipment, Optical fibers, Optical receivers, Optical transmitters, Vertical cavity surface emitting lasers, verticalcavity surface-emitting lasers, Wireless communication},
pubstate = {published},
tppubtype = {article}
}
A 5×5 VCSEL array-based optical wireless communication multi-beam transmitter is designed and simulated. Each element of the array addresses a separate spatial attocell. A microlens-array based homogenizer achieves uniform coverage at the receiver plane from each multi-mode VCSEL output. 1 m2 total coverage is achieved with each attocell covering an area of 400 cm2 at a range of 3 m. For a proof-of-concept demonstration a 1×3 channel VCSEL array-based transmitter prototype is experimentally tested. The performance is verified by demonstrating three channels achieving ∼ 0.12 mW/m2 uniform power with negligible optical interference to adjacent attocells (<-14 dB). With a simple receiver design using low cost, off-the-shelf components, each channel of the transmitter achieves ∼10 Gb/s throughput using OFDM within 7 cm lateral range and > 4 Gb/s within 12 cm lateral range at 3 m. The transmitter meets eye-safety restrictions and could be scaled to 250 Gb/s aggregate data rate by employing all 25 VCSELs with independent OFDM modulation.
5.
Singh, Jitendra; Mehrotra, Anand; Srivastava, Suraj; Jagannatham, Aditya K.; Hanzo, Lajos
Spectral Efficiency Maximization for Mmwave MIMO-Aided Integrated Sensing and Communication Under Practical Constraints Journal Article
In: IEEE Transactions on Vehicular Technology, pp. 1–16, 2025, ISSN: 1939-9359.
Abstract | Links | BibTeX | Tags: Copper, Hybrid power systems, Integrated sensing and communication, Interference, millimeter wave, Millimeter wave communication, Optimization, Radar, radar beampattern similarity, Radio frequency, Signal to noise ratio, Spectral efficiency
@article{singh_spectral_2025,
title = {Spectral Efficiency Maximization for Mmwave MIMO-Aided Integrated Sensing and Communication Under Practical Constraints},
author = {Jitendra Singh and Anand Mehrotra and Suraj Srivastava and Aditya K. Jagannatham and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/11027785},
doi = {10.1109/TVT.2025.3577955},
issn = {1939-9359},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {IEEE Transactions on Vehicular Technology},
pages = {1–16},
abstract = {A hybrid transmit precoder (TPC) and receive combiner (RC) pair is conceived for millimeter wave (mmWave) multiple input multiple output (MIMO) integrated sensing and communication (ISAC) systems. The proposed design considers a practical mean squared error (MSE) constraint between the desired and the achieved beampatterns constructed for identifying radar targets (RTs). To achieve optimal performance, we formulate an optimization problem relying on sum spectral efficiency (SE) maximization of the communication users (CUs), while satisfying certain radar beampattern similarity (RBPS), total transmit power, and constant modulus constraints, where the latter are attributed to the hybrid mmWave MIMO architecture. Since the aforementioned problem is non-convex and intractable, a sequential approach is proposed wherein the TPCs are designed first, followed by the RCs. To deal with the non-convex MSE and constant modulus constraints in the TPC design problem, we propose a majorization and minimization (MM) based Riemannian conjugate gradient (RCG) method, which restricts the tolerable MSE of the beampattern to within a predefined limit. Moreover, the least squares and the zero-forcing methods are adopted for maximizing the sum-SE and for mitigating the multiuser interference (MUI), respectively. Furthermore, to design the RC at each CU, we propose a linear MM-based blind combiner (LMBC) scheme that does not rely on the knowledge of the TPC at the CUs and has a low complexity. To achieve user fairness, we further extend the proposed sequential approach for maximizing the geometric mean (GM) of the CU's rate. Simulation results are presented, which show the superior performance of the proposed hybrid TPC and RC in comparison to the state-of-the-art designs in the mmWave MIMO ISAC systems under consideration.},
keywords = {Copper, Hybrid power systems, Integrated sensing and communication, Interference, millimeter wave, Millimeter wave communication, Optimization, Radar, radar beampattern similarity, Radio frequency, Signal to noise ratio, Spectral efficiency},
pubstate = {published},
tppubtype = {article}
}
A hybrid transmit precoder (TPC) and receive combiner (RC) pair is conceived for millimeter wave (mmWave) multiple input multiple output (MIMO) integrated sensing and communication (ISAC) systems. The proposed design considers a practical mean squared error (MSE) constraint between the desired and the achieved beampatterns constructed for identifying radar targets (RTs). To achieve optimal performance, we formulate an optimization problem relying on sum spectral efficiency (SE) maximization of the communication users (CUs), while satisfying certain radar beampattern similarity (RBPS), total transmit power, and constant modulus constraints, where the latter are attributed to the hybrid mmWave MIMO architecture. Since the aforementioned problem is non-convex and intractable, a sequential approach is proposed wherein the TPCs are designed first, followed by the RCs. To deal with the non-convex MSE and constant modulus constraints in the TPC design problem, we propose a majorization and minimization (MM) based Riemannian conjugate gradient (RCG) method, which restricts the tolerable MSE of the beampattern to within a predefined limit. Moreover, the least squares and the zero-forcing methods are adopted for maximizing the sum-SE and for mitigating the multiuser interference (MUI), respectively. Furthermore, to design the RC at each CU, we propose a linear MM-based blind combiner (LMBC) scheme that does not rely on the knowledge of the TPC at the CUs and has a low complexity. To achieve user fairness, we further extend the proposed sequential approach for maximizing the geometric mean (GM) of the CU's rate. Simulation results are presented, which show the superior performance of the proposed hybrid TPC and RC in comparison to the state-of-the-art designs in the mmWave MIMO ISAC systems under consideration.
6.
Soleymani, Mohammad; Santamaria, Ignacio; Jorswieck, Eduard; Renzo, Marco Di; Schober, Robert; Hanzo, Lajos
Rate Splitting Multiple Access for RIS-aided URLLC MIMO Broadcast Channels Journal Article
In: IEEE Transactions on Wireless Communications, pp. 1–1, 2025, ISSN: 1558-2248.
Abstract | Links | BibTeX | Tags: 6G mobile communication, Channel coding, Europe, Finite block length coding, Interference, low latency, max-min energy efficiency, max-min rate, MIMO, MIMO systems, MISO, NOMA, reconfigurable intelligent surface, Reliability, Resource management, Ultra reliable low latency communication, ultra-reliable communications
@article{soleymani_rate_2025,
title = {Rate Splitting Multiple Access for RIS-aided URLLC MIMO Broadcast Channels},
author = {Mohammad Soleymani and Ignacio Santamaria and Eduard Jorswieck and Marco Di Renzo and Robert Schober and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/11123651},
doi = {10.1109/TWC.2025.3591365},
issn = {1558-2248},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {IEEE Transactions on Wireless Communications},
pages = {1–1},
abstract = {The performance of modern wireless communication systems is typically limited by interference. The impact of interference can be even more severe in ultra-reliable and low-latency communication (URLLC) use cases. A powerful tool for managing interference is rate splitting multiple access (RSMA), which encompasses many multiple-access technologies like non-orthogonal multiple access (NOMA), spatial division multiple access (SDMA), and broadcasting. Another effective technology to enhance the performance of URLLC systems and mitigate interference is constituted by reconfigurable intelligent surfaces (RISs). This paper develops RSMA schemes for multi-user multiple-input multiple-output (MIMO) RIS-aided broad-cast channels (BCs) based on finite block length (FBL) coding. We show that RSMA and RISs can substantially improve the spectral efficiency (SE) and energy efficiency (EE) of MIMO RIS-aided URLLC systems. Additionally, the gain of employing RSMA and RISs noticeably increases when the reliability and latency constraints are more stringent. Furthermore, RISs impact RSMA differently, depending on the user load. If the system is underloaded, RISs are able to manage the interference sufficiently well, making the gains of RSMA small. However, when the user load is high, RISs and RSMA become synergetic.},
keywords = {6G mobile communication, Channel coding, Europe, Finite block length coding, Interference, low latency, max-min energy efficiency, max-min rate, MIMO, MIMO systems, MISO, NOMA, reconfigurable intelligent surface, Reliability, Resource management, Ultra reliable low latency communication, ultra-reliable communications},
pubstate = {published},
tppubtype = {article}
}
The performance of modern wireless communication systems is typically limited by interference. The impact of interference can be even more severe in ultra-reliable and low-latency communication (URLLC) use cases. A powerful tool for managing interference is rate splitting multiple access (RSMA), which encompasses many multiple-access technologies like non-orthogonal multiple access (NOMA), spatial division multiple access (SDMA), and broadcasting. Another effective technology to enhance the performance of URLLC systems and mitigate interference is constituted by reconfigurable intelligent surfaces (RISs). This paper develops RSMA schemes for multi-user multiple-input multiple-output (MIMO) RIS-aided broad-cast channels (BCs) based on finite block length (FBL) coding. We show that RSMA and RISs can substantially improve the spectral efficiency (SE) and energy efficiency (EE) of MIMO RIS-aided URLLC systems. Additionally, the gain of employing RSMA and RISs noticeably increases when the reliability and latency constraints are more stringent. Furthermore, RISs impact RSMA differently, depending on the user load. If the system is underloaded, RISs are able to manage the interference sufficiently well, making the gains of RSMA small. However, when the user load is high, RISs and RSMA become synergetic.
7.
Hong, Zekun; Sugiura, Shinya; Xu, Chao; Hanzo, Lajos
Precoded Faster-Than-Nyquist Signaling Using Optimal Power Allocation for OTFS Journal Article
In: IEEE Wireless Communications Letters, vol. 14, no. 1, pp. 173–177, 2025, ISSN: 2162-2345.
Abstract | Links | BibTeX | Tags: Bandwidth, Delays, Doppler shift, doubly selective fading, Faster-than-Nyquist signaling, information rate, Information rates, Interference, mutual information, OTFS, Precoding, Pulse shaping methods, Receivers, Resource management, Symbols, Time-frequency analysis
@article{hong_precoded_2025,
title = {Precoded Faster-Than-Nyquist Signaling Using Optimal Power Allocation for OTFS},
author = {Zekun Hong and Shinya Sugiura and Chao Xu and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10742918},
doi = {10.1109/LWC.2024.3491777},
issn = {2162-2345},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {IEEE Wireless Communications Letters},
volume = {14},
number = {1},
pages = {173–177},
abstract = {A precoded orthogonal time frequency space (OTFS) modulation scheme relying on faster-than-Nyquist (FTN) transmission over doubly selective fading channels is proposed, which enhances the spectral efficiency and improves the Doppler resilience. We derive the input-output relationship of the FTN signaling in the delay-Doppler domain. Eigenvalue decomposition (EVD) is used for eliminating both the effects of inter-symbol interference and correlated additive noise encountered in the delay-Doppler domain to enable efficient symbol-by-symbol demodulation. Furthermore, the power allocation coefficients of individual frames are optimized for maximizing the mutual information under the constraint of the derived total transmit power. Our performance results demonstrate that the proposed FTN-based OTFS scheme can enhance the information rate while achieving a comparable BER performance to that of its conventional Nyquist-based OTFS counterpart that employs the same root-raised-cosine shaping filter.},
keywords = {Bandwidth, Delays, Doppler shift, doubly selective fading, Faster-than-Nyquist signaling, information rate, Information rates, Interference, mutual information, OTFS, Precoding, Pulse shaping methods, Receivers, Resource management, Symbols, Time-frequency analysis},
pubstate = {published},
tppubtype = {article}
}
A precoded orthogonal time frequency space (OTFS) modulation scheme relying on faster-than-Nyquist (FTN) transmission over doubly selective fading channels is proposed, which enhances the spectral efficiency and improves the Doppler resilience. We derive the input-output relationship of the FTN signaling in the delay-Doppler domain. Eigenvalue decomposition (EVD) is used for eliminating both the effects of inter-symbol interference and correlated additive noise encountered in the delay-Doppler domain to enable efficient symbol-by-symbol demodulation. Furthermore, the power allocation coefficients of individual frames are optimized for maximizing the mutual information under the constraint of the derived total transmit power. Our performance results demonstrate that the proposed FTN-based OTFS scheme can enhance the information rate while achieving a comparable BER performance to that of its conventional Nyquist-based OTFS counterpart that employs the same root-raised-cosine shaping filter.
8.
Singh, Jitendra; Gupta, Awadhesh; Jagannatham, Aditya K.; Hanzo, Lajos
Multi-Beam Object-Localization for Millimeter-Wave ISAC-Aided Connected Autonomous Vehicles Journal Article
In: IEEE Transactions on Vehicular Technology, vol. 74, no. 1, pp. 1725–1729, 2025, ISSN: 1939-9359.
Abstract | Links | BibTeX | Tags: connected autonomous vehicles (CAVs), Copper, Integrated sensing and communication, Integrated sensing and communication (ISAC), Interference, millimeter wave, Millimeter wave communication, Optimization, Radio frequency, sensing beampattern (SBP) gain, Signal to noise ratio
@article{singh_multi-beam_2025,
title = {Multi-Beam Object-Localization for Millimeter-Wave ISAC-Aided Connected Autonomous Vehicles},
author = {Jitendra Singh and Awadhesh Gupta and Aditya K. Jagannatham and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10677488},
doi = {10.1109/TVT.2024.3451480},
issn = {1939-9359},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {IEEE Transactions on Vehicular Technology},
volume = {74},
number = {1},
pages = {1725–1729},
abstract = {Millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems capable of integrated sensing and communication (ISAC) constitute a key technology for connected autonomous vehicles (CAVs). In this context, we propose a multi-beam object-localization (MBOL) model for enhancing the sensing beampattern (SBP) gain of adjacent objects in CAV scenarios. Given the ultra-narrow beams of mmWave MIMO systems, a single pencil beam is unsuitable for closely located objects, which tend to require multiple beams. Hence, we formulate the SBP gain maximization problem, considering also the constraints on the signal-to-interference and noise ratio (SINR) of the communication users (CUs), on the transmit power, and the constant modulus of the phase-shifters in the mmWave hybrid transceiver. To solve this non-convex problem, we propose a penalty-based triple alternating optimization algorithm to design the hybrid beamformer. Finally, simulation results are provided for demonstrating the efficacy of the proposed model.},
keywords = {connected autonomous vehicles (CAVs), Copper, Integrated sensing and communication, Integrated sensing and communication (ISAC), Interference, millimeter wave, Millimeter wave communication, Optimization, Radio frequency, sensing beampattern (SBP) gain, Signal to noise ratio},
pubstate = {published},
tppubtype = {article}
}
Millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems capable of integrated sensing and communication (ISAC) constitute a key technology for connected autonomous vehicles (CAVs). In this context, we propose a multi-beam object-localization (MBOL) model for enhancing the sensing beampattern (SBP) gain of adjacent objects in CAV scenarios. Given the ultra-narrow beams of mmWave MIMO systems, a single pencil beam is unsuitable for closely located objects, which tend to require multiple beams. Hence, we formulate the SBP gain maximization problem, considering also the constraints on the signal-to-interference and noise ratio (SINR) of the communication users (CUs), on the transmit power, and the constant modulus of the phase-shifters in the mmWave hybrid transceiver. To solve this non-convex problem, we propose a penalty-based triple alternating optimization algorithm to design the hybrid beamformer. Finally, simulation results are provided for demonstrating the efficacy of the proposed model.
9.
Mobini, Zahra; Ngo, Hien Quoc; Matthaiou, Michail; Hanzo, Lajos
Cell-Free Massive MIMO Surveillance of Multiple Untrusted Communication Links Journal Article
In: IEEE Internet of Things Journal, vol. 11, no. 20, pp. 33010–33026, 2024, ISSN: 2327-4662.
Abstract | Links | BibTeX | Tags: Cell-free massive multiple-input-multiple-output (CF-mMIMO), Communication system security, Interference, Jamming, Massive MIMO, monitoring node (MN) mode assignment, monitoring success probability (MSP), Power control, proactive monitoring, Surveillance, Technological innovation, Wireless communication, wireless information surveillance
@article{mobini_cell-free_2024,
title = {Cell-Free Massive MIMO Surveillance of Multiple Untrusted Communication Links},
author = {Zahra Mobini and Hien Quoc Ngo and Michail Matthaiou and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10584102},
doi = {10.1109/JIOT.2024.3422676},
issn = {2327-4662},
year = {2024},
date = {2024-10-01},
urldate = {2025-10-08},
journal = {IEEE Internet of Things Journal},
volume = {11},
number = {20},
pages = {33010–33026},
abstract = {A cell-free massive multiple-input-multiple-output (CF-mMIMO) system is considered for enhancing the monitoring performance of wireless surveillance, where a large number of distributed multiantenna aided legitimate monitoring nodes (MNs) proactively monitor multiple distributed untrusted communication links. We consider two types of MNs whose task is to either observe the untrusted transmitters or jam the untrusted receivers. We first analyze the performance of CF-mMIMO surveillance relying on both maximum ratio (MR) and partial zero-forcing (PZF) combining schemes and derive closed-form expressions for the monitoring success probability (MSP) of the MNs. We then propose a joint optimization technique that designs the MN mode assignment, power control, and MN-weighting coefficient control to enhance the MSP based on the long-term statistical channel state information knowledge. This challenging problem is effectively transformed into tractable forms and efficient algorithms are proposed for solving them. Numerical results show that our proposed CF-mMIMO surveillance system considerably improves the monitoring performance with respect to a full-duplex co-located massive multiple-input-multiple-output (MIMO) proactive monitoring system. More particularly, when the untrusted pairs are distributed over a wide area and use the MR combining, the proposed solution provides nearly a thirty-fold improvement in the minimum MSP over the co-located massive MIMO baseline, and forty-fold improvement, when the PZF combining is employed.},
keywords = {Cell-free massive multiple-input-multiple-output (CF-mMIMO), Communication system security, Interference, Jamming, Massive MIMO, monitoring node (MN) mode assignment, monitoring success probability (MSP), Power control, proactive monitoring, Surveillance, Technological innovation, Wireless communication, wireless information surveillance},
pubstate = {published},
tppubtype = {article}
}
A cell-free massive multiple-input-multiple-output (CF-mMIMO) system is considered for enhancing the monitoring performance of wireless surveillance, where a large number of distributed multiantenna aided legitimate monitoring nodes (MNs) proactively monitor multiple distributed untrusted communication links. We consider two types of MNs whose task is to either observe the untrusted transmitters or jam the untrusted receivers. We first analyze the performance of CF-mMIMO surveillance relying on both maximum ratio (MR) and partial zero-forcing (PZF) combining schemes and derive closed-form expressions for the monitoring success probability (MSP) of the MNs. We then propose a joint optimization technique that designs the MN mode assignment, power control, and MN-weighting coefficient control to enhance the MSP based on the long-term statistical channel state information knowledge. This challenging problem is effectively transformed into tractable forms and efficient algorithms are proposed for solving them. Numerical results show that our proposed CF-mMIMO surveillance system considerably improves the monitoring performance with respect to a full-duplex co-located massive multiple-input-multiple-output (MIMO) proactive monitoring system. More particularly, when the untrusted pairs are distributed over a wide area and use the MR combining, the proposed solution provides nearly a thirty-fold improvement in the minimum MSP over the co-located massive MIMO baseline, and forty-fold improvement, when the PZF combining is employed.
10.
Xiao, Yun; Wang, Enhao; Chen, Yunfei
Integrated Sensing and Communications With Multiple Targets and Multiple Users in Mixed Field Proceedings Article
In: 2024 IEEE 24th International Conference on Communication Technology (ICCT), pp. 1288–1292, 2024, ISSN: 2576-7828, (ISSN: 2576-7828).
Abstract | Links | BibTeX | Tags: Antenna arrays, Array signal processing, Beamforming, far-filed, Integrated sensing and communication, integrated sensing and communications, Interference, mixed field, model mismatch, multiple-target, near-field, Next generation networking, Numerical models, Optimization, Propagation losses, Signal to noise ratio, Wireless communication
@inproceedings{xiao_integrated_2024,
title = {Integrated Sensing and Communications With Multiple Targets and Multiple Users in Mixed Field},
author = {Yun Xiao and Enhao Wang and Yunfei Chen},
url = {https://ieeexplore.ieee.org/document/10946468},
doi = {10.1109/ICCT62411.2024.10946468},
issn = {2576-7828},
year = {2024},
date = {2024-10-01},
urldate = {2025-10-08},
booktitle = {2024 IEEE 24th International Conference on Communication Technology (ICCT)},
pages = {1288–1292},
abstract = {Integrated sensing and communications (ISAC) plays a crucial role in the next-generation wireless systems. Owing to the deployment of high carrier frequencies and/or large-scale antenna arrays, targets and communications users in the ISAC systems may follow different propagation models. However, most existing works assume the same propagation model for both communications and sensing. This work considers a practical scenario where multiple targets and communications users are in different fields. Beamforming design is proposed to optimize the sensing signal-to-clutter-plus-noise ratio (SCNR) of each target. Specifically, a sensing performance fairness profile optimization (FPO) problem is formulated, and a Dinkelbach-type algorithm is proposed to solve the problem. Numerical results show the tradeoff between mixed-field communications and sensing, the effects of antenna size and model mismatch between near field and far field on the sensing performance of the mixed-field ISAC.},
note = {ISSN: 2576-7828},
keywords = {Antenna arrays, Array signal processing, Beamforming, far-filed, Integrated sensing and communication, integrated sensing and communications, Interference, mixed field, model mismatch, multiple-target, near-field, Next generation networking, Numerical models, Optimization, Propagation losses, Signal to noise ratio, Wireless communication},
pubstate = {published},
tppubtype = {inproceedings}
}
Integrated sensing and communications (ISAC) plays a crucial role in the next-generation wireless systems. Owing to the deployment of high carrier frequencies and/or large-scale antenna arrays, targets and communications users in the ISAC systems may follow different propagation models. However, most existing works assume the same propagation model for both communications and sensing. This work considers a practical scenario where multiple targets and communications users are in different fields. Beamforming design is proposed to optimize the sensing signal-to-clutter-plus-noise ratio (SCNR) of each target. Specifically, a sensing performance fairness profile optimization (FPO) problem is formulated, and a Dinkelbach-type algorithm is proposed to solve the problem. Numerical results show the tradeoff between mixed-field communications and sensing, the effects of antenna size and model mismatch between near field and far field on the sensing performance of the mixed-field ISAC.
11.
Wang, Enhao; Chen, Yunfei; Ikhlef, Aissa; Sun, Hongjian
Dual-user joint sensing and communications with time-divisioned bi-static radar Journal Article
In: IET Communications, vol. 18, no. 17, pp. 1126–1139, 2024, ISSN: 1751-8636, (_eprint: https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/cmu2.12820).
Abstract | Links | BibTeX | Tags: communication complexity, Interference, remote sensing
@article{wang_dual-user_2024,
title = {Dual-user joint sensing and communications with time-divisioned bi-static radar},
author = {Enhao Wang and Yunfei Chen and Aissa Ikhlef and Hongjian Sun},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1049/cmu2.12820},
doi = {10.1049/cmu2.12820},
issn = {1751-8636},
year = {2024},
date = {2024-01-01},
urldate = {2025-10-08},
journal = {IET Communications},
volume = {18},
number = {17},
pages = {1126–1139},
abstract = {Joint sensing and communications systems have gained significant research interest by merging sensing capabilities with communication functionalities. However, few works have examined the case of multiple users. This work investigates a dual-user joint sensing and communications system, focusing on the interference between the users that explores the optimal performance trade-offs through a time-division approach. Bi-static radar setting is considered. Two typical strategies under this approach are studied: one in which both users follow the same order of communications and then sensing, and the other in which the tasks are performed in opposite order at two users. In each strategy, the sum rate and the detection probability are evaluated and optimized. The results show that the opposite order strategy offers superior performance to the same order strategy, and they also quantify their performance difference. This research highlights the potential benefits of time-division strategies and multiple users in joint sensing and communications systems.},
note = {_eprint: https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/cmu2.12820},
keywords = {communication complexity, Interference, remote sensing},
pubstate = {published},
tppubtype = {article}
}
Joint sensing and communications systems have gained significant research interest by merging sensing capabilities with communication functionalities. However, few works have examined the case of multiple users. This work investigates a dual-user joint sensing and communications system, focusing on the interference between the users that explores the optimal performance trade-offs through a time-division approach. Bi-static radar setting is considered. Two typical strategies under this approach are studied: one in which both users follow the same order of communications and then sensing, and the other in which the tasks are performed in opposite order at two users. In each strategy, the sum rate and the detection probability are evaluated and optimized. The results show that the opposite order strategy offers superior performance to the same order strategy, and they also quantify their performance difference. This research highlights the potential benefits of time-division strategies and multiple users in joint sensing and communications systems.