IEEE Open Journal of the Communications Society最新文献

{"title":"Leveraging Large Language Models for Integrated Satellite-Aerial-Terrestrial Networks: Recent Advances and Future Directions","authors":"Shumaila Javaid;Ruhul Amin Khalil;Nasir Saeed;Bin He;Mohamed-Slim Alouini","doi":"10.1109/OJCOMS.2024.3522103","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3522103","url":null,"abstract":"Integrated satellite, aerial, and terrestrial networks (ISATNs) represent a sophisticated convergence of diverse communication technologies to ensure seamless connectivity across different altitudes and platforms. This paper explores the transformative potential of integrating Large Language Models (LLMs) into ISATNs, leveraging advanced Artificial Intelligence (AI) and Machine Learning (ML) capabilities to enhance these networks. We outline the current architecture of ISATNs and highlight the significant role LLMs can play in optimizing data flow, signal processing, and network management to advance 5G/6G communication technologies through advanced predictive algorithms and real-time decision-making. A comprehensive analysis of ISATN components is conducted, assessing how LLMs can effectively address traditional data transmission and processing bottlenecks. The paper delves into the network management challenges within ISATNs, emphasizing the necessity for sophisticated resource allocation strategies, traffic routing, and security management to ensure seamless connectivity and optimal performance under varying conditions. Furthermore, we examine the technical challenges and limitations associated with integrating LLMs into ISATNs, such as data integration for LLM processing, scalability issues, latency in decision-making processes, and the design of robust, fault-tolerant systems. The study also identifies critical future research directions for fully harnessing LLM capabilities in ISATNs, which is important for enhancing network reliability, optimizing performance, and achieving a truly interconnected and intelligent global network system.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"399-432"},"PeriodicalIF":6.3,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10813004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Joint Latency-Energy Minimization for Fog-Assisted Wireless IoT Networks","authors":"Farshad Shams;Vincenzo Lottici;Zhi Tian","doi":"10.1109/OJCOMS.2024.3522256","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3522256","url":null,"abstract":"This work aims to present a joint resource allocation method for a fog-assisted network wherein IoT wireless devices simultaneously offload their tasks to a serving fog node. The main contribution is to formulate joint minimization of service latency and energy consumption objectives subject to both radio and computing constraints. Moreover, unlike previous works that set a fixed value to the circuit power dissipated to operate a wireless device, practical models are considered. To derive the Pareto boundary between two conflicting objectives we consider, Tchebyshev theorem is used for each wireless device. The interactions among IoT devices are represented through a cooperative Nash bargaining framework, with the unique Nash equilibrium (NE) being computed via a block coordinate descent method. Numerical results obtained using realistic models are presented to corroborate the effectiveness of the proposed algorithm.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"516-530"},"PeriodicalIF":6.3,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10816032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wavefield Networked Sensing: Principles, Algorithms, and Applications","authors":"Marco Manzoni;Dario Tagliaferri;Stefano Tebaldini;Marouan Mizmizi;Andrea Virgilio Monti-Guarnieri;Claudio Maria Prati;Umberto Spagnolini","doi":"10.1109/OJCOMS.2024.3521359","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3521359","url":null,"abstract":"Networked sensing refers to the capability of multiple wireless terminals to cooperate with the aim of enhancing specific figures of merit, e.g., positioning accuracy or imaging resolution. Regarding radio-based sensing, it is essential to understand when and how sensing terminals should cooperate, namely the best strategy that trades between performance and cost (e.g., energy consumption, communication overhead, and complexity). This tutorial paper revises networked sensing from a wavefield interaction perspective, aiming to provide a general theoretical benchmark to evaluate its imaging performance bounds and to guide the sensing cooperation accordingly. Diffraction tomography theory (DTT) is the method to quantify the imaging resolution of any radio sensing experiment from inspection of its spectral (or wavenumber) content. In networked sensing, the image formation is based on the back-projection integral, valid for any network topology and physical configuration of the terminals. The wavefield networked sensing is a framework in which multiple sensing terminals cooperate during the acquisition process to maximize the imaging quality (resolution and sidelobes suppression) by pursuing the wavenumber tessellation principle. We discuss all the coherent data fusion possibilities between sensing terminals and possible killer applications. Remarkably, we show the possibility that the proposed method allows obtaining high-quality images of the environment in limited bandwidth conditions, leveraging the coherent combination of multiple multi-static low-resolution images.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"181-197"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10811966","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Generic Millimeter Wave and Terahertz Spectrum Reuse Model for In-Building Multi-Band Small Cells: Achieving Spectral and Energy Efficiencies of 6G","authors":"Rony K. Saha","doi":"10.1109/OJCOMS.2024.3521503","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3521503","url":null,"abstract":"This paper presents a generic spectrum reuse model (GSRM) to reuse millimeter wave (mmWave) and terahertz (THz) spectrum in multi-band-enabled small cells located within multi-story buildings to address high spectral and energy efficiencies of sixth-generation (6G) mobile networks. For mmWave and THz bands, we consider 28 GHz, 142 GHz, 250 GHz, and 300 GHz bands, and each small cell is assumed to be equipped with these multiple bands. In developing GSRM, we first characterize interferences to derive a minimum distance between apartments of co-channel small cells at both intra-floor and inter-floor levels for each band leading to the formation of a 3-dimensional (3D) cluster of apartments such that the whole spectrum of the corresponding band is allocated to small cells within the cluster. The same spectrum is reused further in small cells of all adjacent 3D clusters within the building. We consider a random distribution of small cells within each 3D cluster. Two scenarios are considered where scenario 1 has the same 3D cluster size for each band, and scenario 2 considers different 3D cluster sizes corresponding to the respective band. We formulate the spectral efficiency (SE) and energy efficiency (EE) metrics of the proposed GSRM in a multi-tier network and develop an algorithm to evaluate its SE and EE metrics. With extensive system-wide evaluations, we show that compared to scenario 1, the overall SE and EE in scenario 2 are improved by 33.33% and 4.5%, respectively, and the proposed GSRM can achieve the prospective SE and EE requirements for 6G mobile systems.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"198-223"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10812825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Blockchain-Assisted Fair Exchange Signature Protocol Using Quantum Key Distribution for Metaverse Environment","authors":"Sunil Prajapat;Pankaj Kumar;Goutham Reddy Alavalapati","doi":"10.1109/OJCOMS.2024.3522000","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3522000","url":null,"abstract":"The metaverse has profoundly altered the conventional online landscape and has attracted significant interest from researchers and industry professionals. As the metaverse changes quickly, it needs strong and safe cryptographic solutions to make sure that transactions are fair and safe in its highly connected world. This paper presents a novel blockchain-assisted fair exchange signature protocol leveraging quantum key distribution (QKD) to ensure security against both classical and quantum adversaries. The suggested protocol combines blockchain technology with quantum key distribution to create an exchange framework that can’t be changed, is clear, and can’t be tampered with. It also uses quantum mechanics to create keys that are always safe. By incorporating a fair exchange mechanism, the protocol guarantees that either both parties fulfill their obligations or neither party benefits, addressing trust issues in decentralized metaverse transactions. Furthermore, we provide a detailed analysis of the protocol’s security, efficiency, and scalability, highlighting its resistance to quantum attacks and its suitability for real-time applications in the metaverse. Simulation results demonstrate that the protocol significantly enhances exchange fairness, minimizes latency, and ensures robust authentication, making it a promising candidate for securing transactions in next-generation digital ecosystems. Web 3.0 technologies provide a resolution by facilitating a decentralized metaverse ecology. The suggested protocol utilizes quantum fundamentals to facilitate safe communication, while the incorporation of quantum cryptography with Web 3.0 improves the efficiency, security, and authenticity of metaverse environments. We test the proposed quantum signature scheme both theoretically and practically using QuantumSim simulations, demonstrating strong signature performance in comparison to other schemes. The results indicate a computational cost of \u0000<inline-formula> <tex-math>$0.815 ms$ </tex-math></inline-formula>\u0000, and communication costs of 1312 bits, demonstrating the protocol’s resilience and performance by conducting a thorough safety and efficiency analysis and demonstrating compliance with essential security features, including unforgeability, undeniability, verifiability, and traceability.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"224-235"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10813001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Signal Detection in Intelligent Reflecting Surface-Assisted NOMA Network Using LSTM Model: A ML Approach","authors":"Haleema Sadia;Hafsa Iqbal;Syed Fawad Hussain;Nasir Saeed","doi":"10.1109/OJCOMS.2024.3521008","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3521008","url":null,"abstract":"Non-orthogonal multiple access (NOMA) is already considered a viable multiple access scheme in fifth-generation networks. However, the stochastic behaviour of a wireless channel becomes a key performance limiting factor. To combat this, and with the advancement of metasurface technology, NOMA networks are being integrated with intelligent reflecting surfaces (IRSs) to improve signal strength. But IRS complicates the detection accuracy of a NOMA system, which is dependent on the correctness of the successive interference cancelation (SIC) process. In this article, we propose a machine learning (ML)-based approach to perform joint channel estimation and signal detection in an IRS-enabled uplink NOMA network under efficient mitigation of SIC error propagation. The proposed scheme exploits a four layer deep learning (DL) model by employing a long short-term memory (LSTM) core structure. Further, to optimize the phase shifts of IRS, we exploit a low complexity iterative solution using the element-wise block coordinate descent (EBCD) method. Monte Carlo simulations are performed to analyze the performance of the proposed scheme, and the findings show a considerable improvement in channel estimation and signal detection using the LSTM based IRS-NOMA receiver. The comparison is made with a maximum likelihood detector employing conventional SIC scheme using least squares and minimum mean square error channel estimation approaches in a realistic path loss channel model with severe inter-symbol interference.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"29-38"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10812022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Approach for Differential Privacy-Preserving Federated Learning","authors":"Anis Elgabli;Wessam Mesbah","doi":"10.1109/OJCOMS.2024.3521651","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3521651","url":null,"abstract":"In this paper, we start with a comprehensive evaluation of the effect of adding differential privacy (DP) to federated learning (FL) approaches, focusing on methodologies employing global (stochastic) gradient descent (SGD/GD), and local SGD/GD techniques. These global and local techniques are commonly referred to as FedSGD/FedGD and FedAvg, respectively. Our analysis reveals that, as far as only one local iteration is performed by each client before transmitting to the parameter server (PS) for FedGD, both FedGD and FedAvg achieve the same accuracy/loss for the same privacy guarantees, despite requiring different perturbation noise power. Furthermore, we propose a novel DP mechanism, which is shown to ensure privacy without compromising performance. In particular, we propose the sharing of a random seed (or a specified sequence of random seeds) among collaborative clients, where each client uses this seed to introduces perturbations to its updates prior to transmission to the PS. Importantly, due to the random seed sharing, clients possess the capability to negate the noise effects and recover their original global model. This mechanism preserves privacy both at a “curious” PS or at external eavesdroppers without compromising the performance of the final model at each client, thus mitigating the risk of inversion attacks aimed at retrieving (partially or fully) the clients’ data. Furthermore, the importance and effect of clipping in the practical implementation of DP mechanisms, in order to upper bound the perturbation noise, is discussed. Moreover, owing to the ability to cancel noise at individual clients, our proposed approach enables the introduction of arbitrarily high perturbation levels, and hence, clipping can be totally avoided, resulting in the same performance of noise-free standard FL approaches.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"466-476"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10812948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DP With Auxiliary Information: Gaussian Mechanism Versus Laplacian Mechanism","authors":"Wessam Mesbah","doi":"10.1109/OJCOMS.2024.3521940","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3521940","url":null,"abstract":"Differential privacy (DP) has been widely used in communication systems, especially those using federated learning or distributed computing. DP comes in the data preparation stage before line coding and transmission. In contrast to the literature where differential privacy is mainly discussed from the point of view of data/computer science, in this paper we approach DP from a perspective that provides a better understanding to the communications engineering community. From this perspective, we show the contrast between the MAP detection problem in communications and the DP problem. In this paper, we consider two DP mechanisms, namely, the Gaussian Mechanism (GM) and the Laplacian Mechanism (LM). We explain why the definition of \u0000<inline-formula> <tex-math>$epsilon$ </tex-math></inline-formula>\u0000-DP is associated with the LM, while we must resort to the definition of (\u0000<inline-formula> <tex-math>$epsilon, delta$ </tex-math></inline-formula>\u0000)-DP if the GM is used. Furthermore, we derive a new lower bound on the perturbation noise required for the GM to guarantee (\u0000<inline-formula> <tex-math>$epsilon, delta$ </tex-math></inline-formula>\u0000)-DP. Although no closed form is obtained for the new lower bound, a very simple one dimensional search algorithm can be used to achieve the lowest possible noise variance. Since the perturbation noise is known to negatively affect the performance of the data analysis (such as the convergence in federated learning), the new lower bound on the perturbation noise is expected to improve the performance over the classical GM. Moreover, we derive the perturbation noise required for both the LM and the GM in case of the adversary having auxiliary information in the form of the prior probabilities of the different databases. We show that the availability of auxiliary information at the adversary, is equivalent to reducing the tolerable privacy leakage, and hence it requires more perturbation noise. Finally, we analytically derive the border between the region where GM is better to use and the region where LM is better to use.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"143-153"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10813007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing and Generalizing Position-Velocity Tracking in Imperfect mmWave Systems Using a Low-Complexity Neural Network","authors":"Deeb Assad Tubail;Mohammed Zourob;Salama Ikki","doi":"10.1109/OJCOMS.2024.3522189","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3522189","url":null,"abstract":"This work aims to enhance and generalize the joint position-velocity tracking process in millimeter wave (mmWave) systems that suffer from hardware impairments (HWIs), all while considering computational complexity. Initially, we investigate the performance of two widely used traditional trackers: the extended Kalman filter (EKF) and the unscented Kalman filter (UKF). Through this investigation, we identify the strengths and limitations of these trackers. Besides, we evaluate the gap between traditional tracking performance and the theoretical optimum by deriving the Bayesian Cramér-Rao Bound (BCRB) as a benchmark. Our findings reveal a significant disparity between the performance of traditional trackers and the benchmark, with performance being influenced by noise characteristics, initial conditions, and the accuracy of prior knowledge about the transition model. To address these challenges, we propose a neural network (NN)-based approach to achieve accurate and generalized tracking without relying on prior knowledge of the transition model, initial conditions, or noise characteristics. Specifically, our method trains a NN that performs effectively under any noise conditions, without needing to recognize the transition model or initial state. To manage the computational demands of the training phase, we employ a low-complexity algorithm, the Extreme Learning Machine (ELM), which calculates weights and biases through closed-form solution, avoiding complex optimization processes. Finally, we validate the accuracy and generality of the ELM tracker through computer simulations, testing it under various scenarios, including Gaussian and non-Gaussian HWI distortions, as well as systems with known transition models and those involving uncharacterized inputs.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"236-251"},"PeriodicalIF":6.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10812951","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-Field Analysis of Extremely Large-Scale MIMO: Power, Correlation, and User Selection","authors":"Xiangyu Cui;Ki-Hong Park;Mohamed Slim Alouini","doi":"10.1109/OJCOMS.2024.3520822","DOIUrl":"https://doi.org/10.1109/OJCOMS.2024.3520822","url":null,"abstract":"With the fast development of communication technology, mobile networks have been evolving from the fifth generation (5G) to the sixth generation (6G). One of the most important technologies in 5G is massive multiple input multiple output (MIMO). In 6G, it has been extended to extremely large-scale MIMO (XL-MIMO) over the TeraHz band, which makes it easier for users to fall into the near-field communication range. However, the previous performance analysis based on the far-field assumption can be very inaccurate under the near-field scenario. Hence, it is necessary to use the near-field channel models to redo these analyses. In this work, we summarize previous analytical results on received signal-to-noise ratio for specific near-field wave models. Then, we derive the generalized formula for the received power of different wave models and antenna structures. We newly derive our closed-form formula for the correlation between different users by the stationary phase method. These results can be applied to different beam-forming schemes and the multipath case. Based on these analytical results, we manage to make a sum rate analysis for different antenna arrays and near-field channel models in a multi-user XL-MIMO system. Finally, with the modification by our analytical result, we show a dramatic speed-up of the previous user selection algorithm, while reaching the same sum rate.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"252-270"},"PeriodicalIF":6.3,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10810362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}