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Science China(Information Sciences) 2024年第1期67卷 203-220页

作者： Jie WANG Jiamin LI Pengcheng ZHU Dongming WANG Hongbiao ZHANG Yue HAO Bin SHENG National Mobile communications research Laboratory Southeast University 2. Purple Mountain Laboratories China Mobile research institute

Network-assisted full-duplex(NAFD) cell-free distributed massive multiple-input multipleoutput(MIMO) systems enable uplink(UL) and downlink(DL) communications within the same timefrequency resources,which potentially reduce latency by avoiding the overhead of switching UL/DL ***,how to choose UL/DL modes remains an important factor affecting system *** the dramatic increase in the number of users and access points(APs),massive access brings significant overhead in the mode ***,the different quality of service(QoS) among users also makes the effective utilization of resources *** one of the most promising technologies in sixth-generation(6G),network slicing enables the adaptive configuration of limited UL/DL resources through the resource isolation assisted NAFD ***,we propose a slicing capacity-centered *** this scheme,APs are motivated by slicing requirements and associated slices to form different *** mode selection and resource allocation are performed within each subsystem to reduce overhead and improve resource *** implement this scheme efficiently,a double-layer deep reinforcement learning(DRL)mechanism is used to realize the joint optimization of mode selection and resource *** results show that the slicing capacity-centered scheme can effectively improve resource utilization and reduce overhead.

关键词： network-assisted full-duplex network slicing mode selection resource optimization deep reinforcement learning

Impact of non-ideal UE hardware on cell-free massive MIMO network with centralized operation

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Science China(Information Sciences) 2024年第4期67卷 255-271页

作者： Ning LI Pingzhi FAN institute of Mobile communications Southwest Jiaotong University

This paper investigates the impact of non-ideal user equipment(UE) hardware on a cell-free(CF) massive MIMO(mMIMO) network with centralized operation under spatially correlated channels. The minimum mean-squared error(MMSE) estimator can be derived with the help of the generic non-ideal UE hardware model. It is demonstrated that even if the effective signal-to-noise ratio approaches infinity, pilot contamination and imperfect hardware can cause a non-zero estimation error floor. After that, a lower bound is determined for the ergodic uplink capacity of the centralized CF mMIMO network under non-ideal UE hardware. Moreover, the optimal receive combining vector is obtained to maximize the uplink spectral efficiency(SE). The maximum ratio(MR) and regularized zero-forcing(RZF) combining schemes are offered as alternatives in light of the computational complexity of the MMSE receiver. Comparing the RZF to the MMSE scheme under different levels of hardware impairments, our findings indicate that the RZF receiver suffers a negligible loss in total SE. For MR combining, a novel closed-form uplink achievable SE expression is obtained based on the MMSE estimator and the use-and-then-forget bounding technique. This expression gives vital insights into the achievable uplink performance with UE hardware impairments. Besides, for various hardware impairment factors, the impact of pilot sequence length on average sum SE is disclosed for different receive combining schemes. To increase the overall SE of the max-min fairness scheme, a heuristic fractional power control scheme with UE hardware impairments is developed, which can essentially avoid sacrificing the SE of other UEs while maximizing the SE of the unluckiest UE in the whole network. Finally,our theoretical performance analysis and power control algorithm are validated by simulation results, and fundamental design guidelines are provided for selecting hardware satisfying the practical UE requirements.

关键词： cell-free massive MIMO centralized operation spatially correlated channels hardware impairments channel estimation uplink spectral efficiency optimal receive combining pilot length design fractional power control

Challenges and Opportunities of Sub-6 GHz Integrated Sensing and communications for 5G-Advanced and Beyond

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Chinese Journal of Electronics 2024年第2期33卷 323-325页

作者： Yuhong HUANG China Mobile research institute China Mobile communications Group Co. Ltd

The integrated sensing and communications(ISAC) technology has been perceived as a key feature of5G-Advanced and beyond mobile communication networks. Compared with sensing in millimeter-wave bands, sensing at sub-6 GHz band is an exceptional incentive to promote the industrialization process of ISAC due to its incomparable advantages in industrial development, especially for intelligent transportation and smart drone networks. This paper elaborates on the top challenges of sub-6 GHz ISAC technologies, as well as the potential solutions to improve the sensing capability.

关键词： Electric potential Millimeter wave technology Transportation Mobile communication Sensors Millimeter wave communication Drones

Application of sparse S transform network with knowledge distillation in seismic attenuation delineation

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Petroleum Science 2024年第4期21卷 2345-2355页

作者： Nai-Hao Liu Yu-Xin Zhang Yang Yang Rong-Chang Liu Jing-Huai Gao Nan Zhang School of Information and communications Engineering Xi'an Jiaotong University School of Software Engineering Xi'an Jiaotong University PetroChina research institute of Petroleum Exploration and Development (RIPED) CNPC research institute of Exploration and Development Yumen Oilfield Company CNPC

Time-frequency analysis is a successfully used tool for analyzing the local features of seismic ***, it suffers from several inevitable limitations, such as the restricted time-frequency resolution,the difficulty in selecting parameters, and the low computational efficiency. Inspired by deep learning,we suggest a deep learning-based workflow for seismic time-frequency analysis. The sparse S transform network(SSTNet) is first built to map the relationship between synthetic traces and sparse S transform spectra, which can be easily pre-trained by using synthetic traces and training labels. Next, we introduce knowledge distillation(KD) based transfer learning to re-train SSTNet by using a field data set without training labels, which is named the sparse S transform network with knowledge distillation(KD-SSTNet).In this way, we can effectively calculate the sparse time-frequency spectra of field data and avoid the use of field training labels. To test the availability of the suggested KD-SSTNet, we apply it to field data to estimate seismic attenuation for reservoir characterization and make detailed comparisons with the traditional time-frequency analysis methods.

关键词： S transform Deep learning Knowledge distillation Transfer learning Seismic attenuation delineation

Doppler-resilient waveform design in integrated MIMO radar-communication systems

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Science China(Information Sciences) 2024年第1期67卷 187-202页

作者： Zhengchun ZHOU Bing LIU Bingsheng SHEN Avik Ranjan ADHIKARY Pingzhi FAN institute of Mobile communications Southwest Jiaotong University Department of Mathematics Southwest Jiaotong University

In recent years,the increased high-rate wireless services(5G and 6G) and reliable sensing capabilities(automotive radar,air traffic control,geophysical monitoring),have led to more serious spectrum ***,radars and communication systems are often seen to be “competing” for the same *** this scenario,an integrated platform for radar and communication systems seems to be an optimal solution to address the *** this paper,we propose a preamble waveform design based on zero-correlation zone(ZCZ) and zero odd-correlation zone(ZOCZ) sequence sets,which are Doppler resilient in multiple-input,multiple-output(MIMO) *** preamble waveforms can be simultaneously used for channel estimation and radar sensing in RadCom *** ambiguity function of the proposed waveforms displays low/zero sidelobes within a time-delay correlation ***,we give some numerical results to show the efficiency of the proposed waveforms in radar sensing and channel estimation.

关键词： ambiguity function correlation channel estimation integrated radar and communication (RadCom) systems MIMO radar zero correlation zone (ZCZ) sequence set zero odd-correlation zone (ZOCZ) sequence set

Near-field channel estimation for extremely large-scale Terahertz communications

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Science China(Information Sciences) 2024年第9期67卷 213-228页

作者： Songjie YANG Yizhou PENG Wanting LYU Ya LI Hongjun HE Zhongpei ZHANG Chau YUEN National Key Laboratory of Wireless communications University of Electronic Science and Technology of China Future research Laboratory China Mobile Research Institute School of Electrical and Electronics Engineering Nanyang Technological University

Future Terahertz communications exhibit significant potential in accommodating ultra-high-rate services. Employing extremely large-scale array antennas is a key approach to realize this potential, as they can harness substantial beamforming gains to overcome the severe path loss and leverage the electromagnetic advantages in the near field. This paper proposes novel estimation methods designed to enhance efficiency in Terahertz widely-spaced multi-subarray(WSMS) systems. Initially, we introduce three sparse channel representation methods: polar-domain representation(PD-R), multi-angular-domain representation(MADR), and two-dimensional polar-angular-domain representation(2D-PAD-R). Each method is meticulously developed for near-field WSMS channels, capitalizing on their sparsity characteristics. Building on this,we propose four estimation frameworks using the sparse recovery theory: polar-domain estimation(PD-E),multi-angular-domain estimation(MAD-E), two-stage polar-angular-domain estimation(TS-PAD-E), and two-dimensional polar-angular-domain estimation(2D-PAD-E). Particularly, 2D-PAD-E, integrating a 2D dictionary process, and TS-PAD-E, with its sequential approach to angle and distance estimation, stand out as particularly effective for near-field angle-distance estimation, enabling decoupled calculation of these parameters. Overall, these frameworks provide versatile and efficient solutions for WSMS channel estimation,balancing low complexity with high-performance outcomes. Additionally, they represent a fresh perspective on near-field signal processing.

关键词： Terahertz communications near field channel estimation widely-spaced multi-subarray sparse recovery

Early warning of core network capacity in space-terrestrial integrated networks

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Journal of Systems Engineering and Electronics 2024年第4期35卷 855-864页

作者： HAN Sai LI Ao ZHANG Dongyue ZHU Bin WANG Zelin WANG Guangquan MIAO Jie MA Hongbing China Unicom research institute Beijing 100044China China United Network communications Group Company Limited Beijing 100033China

With the rapid development of low-orbit satellite com-munication networks both domestically and internationally,space-terrestrial integrated networks will become the future development *** space and terrestrial networks with limi-ted resources,the utilization efficiency of the entire space-terres-trial integrated networks resources can be affected by the core network *** order to improve the response efficiency of core networks expansion construction,early warning of the core network elements capacity is *** on the inte-grated architecture of space and terrestrial network,multidimen-sional factors are considered in this paper,including the number of terminals,login users,and the rules of users’migration during *** artifical intelligence(AI)technologies,the regis-tered users of the access and mobility management function(AMF),authorization users of the unified data management(UDM),protocol data unit(PDU)sessions of session manage-ment function(SMF)are predicted in combination with the num-ber of login users,the number of ***,the core network elements capacity can be predicted in *** proposed method is proven to be effective based on the data from real network.

关键词： space-terrestrial integrated networks core network element capacity artificial intelligent(AI)

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Dynamic Update Scheme of Spectrum Information Based on Spectrum Opportunity Incentive in the Database-Assisted Dynamic Spectrum Management

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China communications 2024年第3期21卷 75-90页

作者： Zhang Yu Chen Yong He Panfeng Cai Yueming Sixty-third research institute National University of Defense TechnologyNanjing 210007China College of communications Engineering Army of Engineering UniversityNanjing 210007China

To solve the problem of delayed update of spectrum information(SI) in the database assisted dynamic spectrum management(DB-DSM), this paper studies a novel dynamic update scheme of SI in DB-DSM. Firstly, a dynamic update mechanism of SI based on spectrum opportunity incentive is established, in which spectrum users are encouraged to actively assist the database to update SI in real time. Secondly, the information update contribution(IUC) of spectrum opportunity is defined to describe the cost of accessing spectrum opportunity for heterogeneous spectrum users, and the profit of SI update obtained by the database from spectrum allocation. The process that the database determines the IUC of spectrum opportunity and spectrum user selects spectrum opportunity is mapped to a Hotelling model. Thirdly, the process of determining the IUC of spectrum opportunities is further modelled as a Stackelberg game by establishing multiple virtual spectrum resource providers(VSRPs) in the database. It is proved that there is a Nash Equilibrium in the game of determining the IUC of spectrum opportunities by VSRPs. Finally, an algorithm of determining the IUC based on a genetic algorithm is designed to achieve the optimal IUC. The-oretical analysis and simulation results show that the proposed method can quickly find the optimal solution of the IUC, and ensure that the spectrum resource provider can obtain the optimal profit of SI update.

关键词： database-assisted dynamic spectrum management Hotelling information updating contribution spectrum information updating Stackelberg

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An ensemble and cost-sensitive learning-based root cause diagnosis scheme for wireless networks with spatially imbalanced user data distribution

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Science China(Information Sciences) 2024年第7期67卷 331-332页

作者： Qi WANG Zhiwen PAN Nan LIU National Mobile communications research Laboratory Southeast University Purple Mountain Laboratories

Root cause diagnosis, a key component of self-healing, plays a vital role in fault management. The spatially imbalanced network key performance indicators (KPIs) reported by users increase the difficulty of identifying root *** [1,2], the image inpainting technique is inspired to address issues caused by sparse reports across the coverage area.

关键词： Wireless networks

Distributed Matching Theory-Based Task Re-Allocating for Heterogeneous Multi-UAV Edge Computing

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China communications 2024年第1期21卷 260-278页

作者： Yangang Wang Xianglin Wei Hai Wang Yongyang Hu Kuang Zhao Jianhua Fan College of communications Engineering Army Engineering University of PLANanjing 210007China The Sixty-Third research institute National University of Defense TechnologyNanjing 210007China

Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge ***,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered ***,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy *** three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making *** tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and ***,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put *** formally proved that a stable matching can be achieved by our *** simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.

关键词： edge computing heterogeneity matching theory service function unmanned aerial vehicle

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