In this paper,average bit error probability(ABEP)bound of optimal maximum likelihood(ML)detector is first derived for ultra massive(UM)multiple-input-multiple-output(MIMO)system with generalized amplitude phase modula...In this paper,average bit error probability(ABEP)bound of optimal maximum likelihood(ML)detector is first derived for ultra massive(UM)multiple-input-multiple-output(MIMO)system with generalized amplitude phase modulation(APM),which is confirmed by simulation results.Furthermore,a minimum residual criterion(MRC)based lowcomplexity near-optimal ML detector is proposed for UM-MIMO system.Specifically,we first obtain an initial estimated signal by a conventional detector,i.e.,matched filter(MF),or minimum mean square error(MMSE)and so on.Furthermore,MRC based error correction mechanism(ECM)is proposed to correct the erroneous symbol encountered in the initial result.Simulation results are shown that the performance of the proposed MRC-ECM based detector is capable of approaching theoretical ABEP of ML,despite only imposing a slightly higher complexity than that of the initial detector.展开更多
This study explored the transformative potential of artificial intelligence(AI)in addressing the challenges posed by terahertz ultra-massive multiple-input multiple-output(UM-MIMO)systems.It begins by outlining the ch...This study explored the transformative potential of artificial intelligence(AI)in addressing the challenges posed by terahertz ultra-massive multiple-input multiple-output(UM-MIMO)systems.It begins by outlining the characteristics of terahertz UM-MIMO systems and identifies three primary challenges for transceiver design:computational complexity,modeling difficulty,and measurement limitations.The study posits that AI provides a promising solution to these challenges.Three systematic research roadmaps are proposed for developing AI algorithms tailored to terahertz UM-MIMO systems.The first roadmap,model-driven deep learning(DL),emphasizes the importance of leveraging available domain knowledge and advocates the adoption of AI only to enhance bottleneck modules within an established signal processing or optimization framework.Four essential steps are discussed:algorithmic frameworks,basis algorithms,loss function design,and neural architecture design.The second roadmap presents channel state information(CSI)foundation models,aimed at unifying the design of different transceiver modules by focusing on their shared foundation,that is,the wireless channel.The training of a single compact foundation model is proposed to estimate the score function of wireless channels,which serve as a versatile prior for designing a wide variety of transceiver modules.Four essential steps are outlined:general frameworks,conditioning,site-specific adaptation,and the joint design of CSI foundation models and model-driven DL.The third roadmap aims to explore potential directions for applying pretrained large language models(LLMs)to terahertz UM-MIMO systems.Several application scenarios are envisioned,including LLM-based estimation,optimization,search,network management,and protocol understanding.Finally,the study highlights open problems and future research directions.展开更多
An ultra-massive distributed virtual environment generally consists of ultra-massive terrain data and a large quantity of objects and their attribute data,such as 2D/3D geometric models,audio/video,images,vectors,char...An ultra-massive distributed virtual environment generally consists of ultra-massive terrain data and a large quantity of objects and their attribute data,such as 2D/3D geometric models,audio/video,images,vectors,characteristics,etc.In this paper,we propose a novel method for constructing distributed scene graphs with high extensibility.This method can support high concurrent interaction of clients and implement various tasks such as editing,querying,accessing and motion controlling.Some application experiments are performed to demonstrate its efficiency and soundness.展开更多
An ultra-massive phased array can be deployed in high-throughput millimeter-wave(mmWave)communication systems to increase the transmission distance.However,when the signal bandwidth is large,the antenna array response...An ultra-massive phased array can be deployed in high-throughput millimeter-wave(mmWave)communication systems to increase the transmission distance.However,when the signal bandwidth is large,the antenna array response changes with the frequency,causing beam squint.In this paper,we investigate the beam squint effect on a high-throughput mmWave communication system with the single-carrier frequency-domain equalization transmission scheme.Specifically,we first view analog beamforming and the physical channel as a spatial equivalent channel.The characteristics of the spatial equivalent channel are analyzed which behaves like frequency-selective fading.To eliminate the deep fading points in the spatial equivalent channel,an advanced analog beamforming method is proposed based on the Zadoff-Chu(ZC)sequence.Then,the low-complexity linear zero-forcing and minimum mean squared error equalizers are considered at the receiver.Simulation results indicate that the proposed ZC-based analog beamforming method can effectively mitigate the performance loss by the beam squint.展开更多
基金supported in part by the National Key Research and Development Program of China under Grant 2019YFB1803400in part by the National Science Foundation of China under Grant 62001179in part by the Fundamental Research Funds for the Central Universities under Grant 2020kfyXJJS111.
文摘In this paper,average bit error probability(ABEP)bound of optimal maximum likelihood(ML)detector is first derived for ultra massive(UM)multiple-input-multiple-output(MIMO)system with generalized amplitude phase modulation(APM),which is confirmed by simulation results.Furthermore,a minimum residual criterion(MRC)based lowcomplexity near-optimal ML detector is proposed for UM-MIMO system.Specifically,we first obtain an initial estimated signal by a conventional detector,i.e.,matched filter(MF),or minimum mean square error(MMSE)and so on.Furthermore,MRC based error correction mechanism(ECM)is proposed to correct the erroneous symbol encountered in the initial result.Simulation results are shown that the performance of the proposed MRC-ECM based detector is capable of approaching theoretical ABEP of ML,despite only imposing a slightly higher complexity than that of the initial detector.
基金supported in part by the Hong Kong Research Grant Council(16209023)。
文摘This study explored the transformative potential of artificial intelligence(AI)in addressing the challenges posed by terahertz ultra-massive multiple-input multiple-output(UM-MIMO)systems.It begins by outlining the characteristics of terahertz UM-MIMO systems and identifies three primary challenges for transceiver design:computational complexity,modeling difficulty,and measurement limitations.The study posits that AI provides a promising solution to these challenges.Three systematic research roadmaps are proposed for developing AI algorithms tailored to terahertz UM-MIMO systems.The first roadmap,model-driven deep learning(DL),emphasizes the importance of leveraging available domain knowledge and advocates the adoption of AI only to enhance bottleneck modules within an established signal processing or optimization framework.Four essential steps are discussed:algorithmic frameworks,basis algorithms,loss function design,and neural architecture design.The second roadmap presents channel state information(CSI)foundation models,aimed at unifying the design of different transceiver modules by focusing on their shared foundation,that is,the wireless channel.The training of a single compact foundation model is proposed to estimate the score function of wireless channels,which serve as a versatile prior for designing a wide variety of transceiver modules.Four essential steps are outlined:general frameworks,conditioning,site-specific adaptation,and the joint design of CSI foundation models and model-driven DL.The third roadmap aims to explore potential directions for applying pretrained large language models(LLMs)to terahertz UM-MIMO systems.Several application scenarios are envisioned,including LLM-based estimation,optimization,search,network management,and protocol understanding.Finally,the study highlights open problems and future research directions.
基金Supported by the National Basic Research Program of China(Grant No.2004CB719403)the National High-Tech Research&Development Program of China(Grant Nos.2006AA01Z334,2007AA01Z318,2009AA01Z324)+1 种基金the National Natural Science Foundation of China(GrantNos.60573151,60703062,60833007)the Marine 908-03-01-10 Project
文摘An ultra-massive distributed virtual environment generally consists of ultra-massive terrain data and a large quantity of objects and their attribute data,such as 2D/3D geometric models,audio/video,images,vectors,characteristics,etc.In this paper,we propose a novel method for constructing distributed scene graphs with high extensibility.This method can support high concurrent interaction of clients and implement various tasks such as editing,querying,accessing and motion controlling.Some application experiments are performed to demonstrate its efficiency and soundness.
基金Project supported by the National Key R&D Program of China(No.2020YFB1805001)the National Natural Science Foundation of China(No.61831004)the Defense Industrial Technology Development Program,China(No.JCKY2016204A603)。
文摘An ultra-massive phased array can be deployed in high-throughput millimeter-wave(mmWave)communication systems to increase the transmission distance.However,when the signal bandwidth is large,the antenna array response changes with the frequency,causing beam squint.In this paper,we investigate the beam squint effect on a high-throughput mmWave communication system with the single-carrier frequency-domain equalization transmission scheme.Specifically,we first view analog beamforming and the physical channel as a spatial equivalent channel.The characteristics of the spatial equivalent channel are analyzed which behaves like frequency-selective fading.To eliminate the deep fading points in the spatial equivalent channel,an advanced analog beamforming method is proposed based on the Zadoff-Chu(ZC)sequence.Then,the low-complexity linear zero-forcing and minimum mean squared error equalizers are considered at the receiver.Simulation results indicate that the proposed ZC-based analog beamforming method can effectively mitigate the performance loss by the beam squint.
