Sixth Generation(6G)mobile communication networks will involve sensing as a new function,with the overwhelming trend of Integrated Sensing And Communications(ISAC).Although expanding the serving range of the networks,...Sixth Generation(6G)mobile communication networks will involve sensing as a new function,with the overwhelming trend of Integrated Sensing And Communications(ISAC).Although expanding the serving range of the networks,there exists performance trade-offbetween communication and sensing,in that they have competitions on the physical resources.Different resource allocation schemes will result in different sensing and communication performance,thus influencing the system’s overall performance.Therefore,how to model the system’s overall performance,and how to optimize it are key issues for ISAC.Relying on the large-scale deployment of the networks,cooperative ISAC has the advantages of wider coverage,more robust performance and good compatibility of multiple monostatic and multistatic sensing,compared to the non-cooperative ISAC.How to capture the performance gain of cooperation is a key issue for cooperative ISAC.To address the aforementioned vital problems,in this paper,we analyze the sensing accuracy gain,propose a unified ISAC performance evaluation framework and design several optimization methods in cooperative ISAC systems.The cooperative sensing accuracy gain is theoretically analyzed via Cramér Rao lower bound.The unified ISAC performance evaluation model is established by converting the communication mutual information to the effective minimum mean squared error.To optimize the unified ISAC performance,we design the optimization algorithms considering three factors:base stations’working modes,power allocation schemes and waveform design.Through simulations,we show the performance gain of the cooperative ISAC system and the effectiveness of the proposed optimization methods.展开更多
Modular floating structures(MFS)offer a sustainable pathway towards the expansion of coastal cities in adaptation tofilooding and sea level rise driven by climate change.It is therefore necessary to develop analytical...Modular floating structures(MFS)offer a sustainable pathway towards the expansion of coastal cities in adaptation tofilooding and sea level rise driven by climate change.It is therefore necessary to develop analytical methods easily accessible to architects or structural engineers for the rapid prototyping of MFS designs.This work develops novel closed‑form expressions describing the rigid body dynamics of symmetrically loaded rectangular pontoons across all six degrees of freedom(DOF)excited by surface waves approaching from any arbitrary direction.The derivations were based on Airy wave theory assuming frequency‑independent added mass and damping.When benchmarked against numerical solutions from ANSYS/AQWA for two MFS prototypes,the analytical approach proved capable of predicting the response amplitude operators(RAO)across all DOFs,wave directions,and structural confiigurations.However,while the response of mass‑dominated DOFs(surge,sway,and yaw)were well captured,the damping ratio for stiffness‑dominated DOFs(heave,roll,and pitch)must be judiciously selected to yield accurate RAO results.A parametric investigation further elucidated the contribution of structural geometry and wave directionality on the critical accelerations experienced by an idealizedfiloating structure founded upon a square pontoon under realistic sea states.It was discovered that the largest accelerations were triggered by waves approaching orthogonally to the pontoon.Ultimately,this work facilitates a more streamlined approach for the dynamic analysis of compliantfiloating bodies to supplement detailed modeling efforts via numerical methods.展开更多
文摘Sixth Generation(6G)mobile communication networks will involve sensing as a new function,with the overwhelming trend of Integrated Sensing And Communications(ISAC).Although expanding the serving range of the networks,there exists performance trade-offbetween communication and sensing,in that they have competitions on the physical resources.Different resource allocation schemes will result in different sensing and communication performance,thus influencing the system’s overall performance.Therefore,how to model the system’s overall performance,and how to optimize it are key issues for ISAC.Relying on the large-scale deployment of the networks,cooperative ISAC has the advantages of wider coverage,more robust performance and good compatibility of multiple monostatic and multistatic sensing,compared to the non-cooperative ISAC.How to capture the performance gain of cooperation is a key issue for cooperative ISAC.To address the aforementioned vital problems,in this paper,we analyze the sensing accuracy gain,propose a unified ISAC performance evaluation framework and design several optimization methods in cooperative ISAC systems.The cooperative sensing accuracy gain is theoretically analyzed via Cramér Rao lower bound.The unified ISAC performance evaluation model is established by converting the communication mutual information to the effective minimum mean squared error.To optimize the unified ISAC performance,we design the optimization algorithms considering three factors:base stations’working modes,power allocation schemes and waveform design.Through simulations,we show the performance gain of the cooperative ISAC system and the effectiveness of the proposed optimization methods.
文摘Modular floating structures(MFS)offer a sustainable pathway towards the expansion of coastal cities in adaptation tofilooding and sea level rise driven by climate change.It is therefore necessary to develop analytical methods easily accessible to architects or structural engineers for the rapid prototyping of MFS designs.This work develops novel closed‑form expressions describing the rigid body dynamics of symmetrically loaded rectangular pontoons across all six degrees of freedom(DOF)excited by surface waves approaching from any arbitrary direction.The derivations were based on Airy wave theory assuming frequency‑independent added mass and damping.When benchmarked against numerical solutions from ANSYS/AQWA for two MFS prototypes,the analytical approach proved capable of predicting the response amplitude operators(RAO)across all DOFs,wave directions,and structural confiigurations.However,while the response of mass‑dominated DOFs(surge,sway,and yaw)were well captured,the damping ratio for stiffness‑dominated DOFs(heave,roll,and pitch)must be judiciously selected to yield accurate RAO results.A parametric investigation further elucidated the contribution of structural geometry and wave directionality on the critical accelerations experienced by an idealizedfiloating structure founded upon a square pontoon under realistic sea states.It was discovered that the largest accelerations were triggered by waves approaching orthogonally to the pontoon.Ultimately,this work facilitates a more streamlined approach for the dynamic analysis of compliantfiloating bodies to supplement detailed modeling efforts via numerical methods.
