In recent years, the mobile crowdsensing (MCS) paradigm has enabled a diverse array of emerging sensing applications by harnessing the collective efforts of ubiquitous mobile users, who collaborate to carry out specific sensing tasks using smart devices. However, the majority of existing works concentrate on a single MCS platform, which struggles to accommodate diverse service requirements. Moreover, these existing researches either consider opportunistic users (OUs) or participatory users (PUs) for task execution, which leads to low task coverage or high recruitment costs, while reducing the sensing quality of tasks. Therefore, in this paper, we introduce a multi-platform scenario where OUs and PUs are combined to complement each other. Then, we formulate a multi-platform hybrid user recruitment (MPHUR) problem within the limited platform budget and user time budget and decompose it into two NP-hard subproblems. To maximize the total sensing quality of tasks, we propose a Two-phase cross-platform Hybrid User recruitment Strategy called THUS. In the first phase, we present a greedy-based opportunistic user recruitment algorithm to match the user-task pair iteratively with maximum sensing quality according to the shortage degree of PUs. In the second phase, the MCS platforms assign PUs to complete the tasks that OUs fail to cover based on their residual budget. We propose a multi-task minimum-cost flow algorithm to recruit PUs for the remaining tasks. The extensive experiments are conducted on two real-world datasets to demonstrate the effectiveness of our proposed THUS.

Split Federated Learning (SFL) is renowned for its privacy-preserving nature and low computational overhead among decentralized machine learning paradigms. In this framework, clients employ lightweight models to process private data locally and transmit intermediate outputs to a powerful server for further computation. However, SFL is a double-edged sword: while it enables edge computing and enhances privacy, it also introduces intellectual property ambiguity as both clients and the server jointly contribute to training. Existing watermarking techniques fail to protect both sides since no single participant possesses the complete model. To address this, we propose RISE, a Robust model Intellectual property protection scheme using client-Server watermark Embedding for SFL. Specifically, RISE adopts an asymmetric client-server watermarking design: the server embeds feature-based watermarks through a loss regularization term, while clients embed backdoor-based watermarks by injecting predefined trigger samples into private datasets. This co-embedding strategy enables both clients and the server to verify model ownership. Experimental results on standard datasets and multiple network architectures show that RISE achieves over $95\%$ watermark detection rate ($p-value \lt 0.03$) across most settings. It exhibits no mutual interference between client- and server-side watermarks and remains robust against common removal attacks.

Edge caching alleviates backhaul pressure and enhances video service quality by deploying video content near user devices. However, the limited storage capacity of edge servers struggles to cope with the exponential growth of video data, challenging the delivery of high-quality video services. While both Device-to-Device (D2D) caching and multi-bitrate video technology are promising solutions to relieve the pressure on edge servers, existing research suffers from a key limitation: studies on multi-bitrate caching are predominantly focused on the edge layer, while D2D caching is often limited to single-bitrate scenarios. This isolation neglects the significant benefits of integrating D2D caching with multi-bitrate technology and fails to develop a cross-layer caching strategy for multi-bitrate videos. To address this limitation, we propose a D2D-enhanced Multi-bitrate video cAching straTEgy (MATE) for cloud-edge-device collaborative networks. We formulate a joint service latency and caching replacement cost optimization problem, which can be modeled as a mixed-integer programming problem. To overcome the coupling between caching strategies at the edge layer and device layer, we employ an alternating iterative optimization approach to decouple the original problem into two subproblems. We design an edge-device double-layer joint caching strategy, i.e., a device-layer caching strategy based on greedy algorithm and Lagrange multipliers, and an edge-layer caching strategy based on multi-agent twin delayed deep deterministic policy gradient algorithm. Extensive simulations are conducted to demonstrate the effectiveness of the proposed MATE.

Mobile users can offload their tasks to adjacent edge servers to enhance service quality. These servers require suitable reimbursements to cover the operational and energy consumption costs incurred while assisting with offloaded tasks. Although previous studies have examined market mechanisms for multiple users offloading tasks to multiple servers, most of them have not investigated the market mechanism for splittable task offloading, where tasks can be divided into multiple subtasks and offloaded to multiple servers. In this work, we propose a novel edge computing marketplace that focuses on splittable task offloading in multi-user multi-server scenarios with the aim of maximizing social welfare. Designing such a marketplace presents several challenges. First, the problem of task and computing resource division introduced in this context results in a complex solution space, and the division decisions are interdependent. Second, the users and edge servers have conflicting objectives and hidden utility/cost information. To overcome these challenges and achieve socially optimal market operation, we devise an Iterative DoublE Auction (IDEA) mechanism.IDEAemploys a broker to facilitate the interactions between users and edge servers and induces truthful reporting of hidden information through iterative updates to the allocation and pricing rules. Rigorous theoretical analysis and extensive simulations demonstrate the effectiveness of the proposedIDEAmechanism in achieving optimal social performance.

To efficiently execute tasks, computation resource requesters (CRRs) with limited resources can offload their tasks to nearby computation resource providers (CRPs) with spare computing capacity. These CRPs require appropriate incentives to compensate for their incurred costs when helping process the offloaded tasks. Although several mechanisms have been designed to incentivize CRPs, none of them have investigated the incentive mechanism considering price-setting and price-taking CRPs simultaneously. In this work, we propose an incentive framework for task offloading in the edge computing marketplace that includes both price-setting and price-taking CRPs. We model the CRR's interactions with both types of CRPs as a three-stage Stackelberg game to maximize the profit for both the CRR and CRPs. We prove the existence of a unique subgame perfect equilibrium (SPE) of the formulated game and further develop iterative algorithms for the CRR and price-setting CRPs to achieve the equilibrium. Through the designed algorithms, each CRP does not require complete information about the CRR and other CRPs. Extensive simulations demonstrate that offloading tasks to both price-setting and price-taking CRPs achieves higher profits for the CRR and price-setting CRPs compared to offloading tasks solely to price-setting CRPs. Additionally, the obtained SPE can achieve near-optimal social welfare.

Mobile edge computing (MEC) is considered a promising technology to provide low-latency services by keeping computing and other resources physically close to where they are needed. The functions implemented through network function virtualization (NFV) technology in MEC are called virtual network function (VNF) instances, and the deployment and scheduling of VNF instances have always been a hot topic. The deployment refers to deploying instances on the edge servers, while scheduling refers to allocating resources to complete user requests. However, most of the existing works fail to jointly consider the deployment and scheduling of VNF instances, which cannot complete user requests reasonably and efficiently. Besides, the deployment cost can be significantly reduced by making users share the same type of instances instead of assigning one to each user. Therefore, the objective of our article is to investigate the efficient deployment and scheduling of VNF instances that are shared among different users under constraints of user delay and network resources. We first build a VNF instance deployment and scheduling model in MEC networks to study how to minimize cost and maximize network throughput under the constraints of user delay and the computing and storage resources of cloudlets. Then, taking advantage of its sharing feature, we propose a set covering-based efficient deployment and scheduling scheme called SCEDS and evaluate its performance by extensive simulations. The simulation results demonstrate the superiority of our proposed method compared to the existing ones.

To enable the inference of high-precision deep neural networks (DNNs) on resource-constrained devices, DNN offloading has been widely explored in recent years. Some works have also integrated the chain-topology DNN (CDNN) offloading with pipeline processing to further reduce inference delay when processing streaming tasks. To improve the accuracy of the inference results, the topology of DNN tends to evolve from chain topology to directed acyclic graph (DAG) topology. However, most of the existing works do not study partitioning and offloading DAG-topology DNNs (DDNNs) for streaming tasks. Moreover, when partitioning computationally expensive DNN models, multipartitioning probably outperforms the bi-partitioning method, and most of the works do not study multipartitioning DAG-topology DNNs. In this article, we propose a more general multipartitioning and offloading method for large-scale DDNNs to process streaming tasks, which can adaptively partition DDNNs into multiple parts considering the computing power and bandwidth of all available computing units. Specifically, we first present a transforming method based on topological sorting that can losslessly transform DAG-topology DNNs into CDNNs. Then, based on greedy and dichotomy ideas, a multipartitioning algorithm is designed to partition and offload CDNNs. In this way, we can solve DDNNs’ multipartitioning problem based on the proposed transforming and partitioning algorithms. Experimentshttps://github.com/sreasearcher/PDD-Codeshow that the method proposed in this article significantly outperforms bi-partitioning and nonpartitioning methods when offloading computationally expensive DNN models.

Federated Learning (FL) has emerged as a fundamental learning paradigm to harness massive data scattered at geo-distributed edge devices in a privacy-preserving way. Given the heterogeneous deployment of edge devices, however, their data are usually Non-IID, introducing significant challenges to FL including degraded training accuracy, intensive communication costs, and high computing complexity. Towards that, traditional approaches typically utilize adaptive mechanisms, which may suffer from scalability issues, increased computational overhead, and limited adaptability to diverse edge environments. To address that, this paper instead leverages the observation that the computation offloading involves inherent functionalities such as node matching and service correlation to achieve data reshaping and proposesFederatedlearning basedoncomputingOffloading (FlocOff) framework, to address data heterogeneity and resource-constrained challenges. Specifically, FlocOff formulates the FL process with Non-IID data in edge scenarios and derives rigorous analysis on the impact of imbalanced data distribution. Based on this, FlocOff decouples the optimization in two steps, namely: 1) Minimizes the Kullback-Leibler (KL) divergence via Computation Offloading scheduling (MKL-CO); 2) Minimizes the Communication Cost through Resource Allocation (MCC-RA). Extensive experimental results demonstrate that the proposed FlocOff effectively improves model convergence and accuracy by 14.3%-32.7% while reducing data heterogeneity under various data distributions.

The proliferation of machine learning (ML) applications has given rise to a new and popular data marketplace paradigm. These marketplaces facilitate ML model requesters in obtaining data from data owners to train their desired models. To mitigate the privacy concerns of data owners, federated learning (FL) has been introduced, enabling collaborative model training without raw data trading. Furthermore, researchers have incorporated differential privacy (DP) techniques into FL, resulting in differentially private federated learning (DPFL) to enhance privacy preservation. However, existing designs of DPFL-based data marketplaces consider a simplified but unrealistic scenario where the model requester holds dominant market power, and data owners cannot set their own prices. In this work, we propose a novel DPFL-based data marketplace that accommodates both price-taking and price-setting data owners. We model the interactions among the model requester and these two types of data owners as a three-stage Stackelberg game, focusing on maximizing the model requester's profit. We rigorously establish that the formulated game is a convex game with a unique subgame perfect equilibrium. Moreover, we devise iterative algorithms to determine the equilibrium strategies for the model requester and price-setting data owners. Notably, our algorithms allow data owners to operate without requiring complete information about the model requester or other data owners. Numerical experiments demonstrate the superiority of our proposed three-stage framework in terms of the model requester's profitability compared to scenarios where only price-taking data owners are involved. Furthermore, we reveal that price competition among price-setting data owners reduces equilibrium market prices.

The widespread deployment of Internet of Things (IoT) devices brings more and more computation intensive or delay sensitive tasks, causing a series of challenges to efficient services. Collaborative edge computing is an effective way to solve them, where the tasks will be processed in the devices, edge servers, and cloud server in parallel. However, the above collaborative paradigm requires dense deployment of base stations (BSs) and consumes lots of energy. To address this problem, in this paper, we introduce energy harvesting technology and construct a collaborative edge computing system powered by hybrid energy. Considering the highly variable task execution delay caused by the resource contention and the unstable energy state, we further introduce the Holt Linear Exponential Smoothing Prediction to predict the delay and then propose an Online Server Control schedule called OSC based on Lyapunov optimization to obtain the optimized offloading decision without the knowledge of the future system state. The extensive simulations illustrate that the proposed OSC outperforms other benchmark ones.

With the widespread application of 5G and the Internet of things (IoT), edge computing and cloud computing have been collaboratively utilized for task offloading and processing. However, though the massive devices (e.g., smartphones) are organized into multi-cells, most of the existing works do not explore the computation offloading for edge-cloud computing under inter-cell interference. Thus, the offloading decisions may be inappropriate as the transmission rate is overestimated. To address this issue, we propose COMEC, a novel Computation Offloading scheme in Multi-cell networks with Edge-Cloud collaboration, which could minimize the total cost in terms of delay and energy consumption. Specifically, we first formulate COMEC as an optimization problem taking into account inter-cell interference. Then, considering the offloading decisions of all users are coupled, a non-cooperative game is formulated to minimize the total cost of each user in a distributed manner. We prove that this game is a general (ordinal) potential game and possesses a pure strategy Nash equilibrium (NE). Based on the finite improvement property of the potential game, we develop the corresponding computation offloading algorithm to achieve the NE. Finally, simulation results show that the proposed scheme can achieve superior performance in overall system cost compared with other baselines.

For the purpose of training a machine learning model via exploiting data from multiple devices without compromising their privacy, federated learning (FL) has become a popular approach. Meanwhile, over-the-air computation (AirComp) enables concurrent model transmission to accelerate model aggregation in the context of FL. However, the performance of model aggregation is significantly hindered by adverse wireless channels. In this paper, we employ intelligent reflecting surface (IRS) to facilitate accurate model aggregation in AirComp-based FL. To ensure compatibility with existing communication standards, this paper adopts uniform quantization for both downlink model broadcast and uplink AirComp-based gradient aggregation. Furthermore, we quantitatively examine the impact of quantization errors on transmission accuracy and convergence bound. To mitigate signal distortion, we employ an alternating optimization algorithm that optimizes the beamforming vector at the base station, the transmit/receive scalars at the devices, and the phase shifts at the IRS. The simulation results provide compelling evidence for the effectiveness and robustness of our proposed method.

With the rapid development of edge data intelligence, task offloading (TO) and resource allocation (RA) optimization in multiaccess edge computing networks can significantly improve the Quality of Service (QoS). However, for the online scenario, traditional methods (e.g., game theory and numerical methods) cannot adapt to dynamic environments. Deep reinforcement learning (DRL) is applied to adjust the policy to get long-term rewards. Nevertheless, since the joint problem of TO and RA is nonconvex and NP-hard, existing DRL methods cannot guarantee high efficiency because of the large action space. To solve the above problem, we propose a fast learning with integrated reward and reduced action space-based DRL framework (FLIRRAS), which adopts a low-complexity approach to jointly optimize TO and RA strategies. The FLIRRAS framework combines DRL with numerical methods to iteratively pursues the discrete TO and continuous RA. Specifically, a deep neural network (DNN) is used to learn environmental information, which can get prior knowledge of the offloading decision. Furthermore, a novel reward integrating the utility of TO and RA is designed to motivate the agent to find the optimal policy. To solve the dilemma that the action space is too large, low-complexity convex optimization methods, i.e., subgradient projection and KKT condition, are used to supplement and adjust the decision, which reduces the network parameters and the decision space. In addition, given the dynamic online environment, we introduce the experience replay mechanism, where policy is updated regularly to reflect the best mapping between states. The experiment results show that the performance of FLIRRAS is better than greedy and other DRL approaches, and it outperforms the latest DRL method by over 18.0% in terms of execution time.

Compressed sensing (CS) has been identified as a good candidate for user detection in grant-free non-orthogonal multiple access (NOMA) by exploiting the inherent sparsity of user activity. However, most of the existing CS-based user detection schemes do not fully utilize the temporal correlation of user activity in NOMA and rely heavily on the unrealistic assumption that the number of active users is known in advance. To address these issues, we propose a temporal correlation enhanced multiuser detection scheme to achieve efficient and pragmatic multiuser detection. First, using 1-bit memory to piggyback the information on whether the active users still have data to transmit, the base station can realize that the active users in the current time slot will turn to be silent or remain active. Then, to make explicit use of the temporal correlation of active user sets, a cross validation based adaptive subspace pursuit (CVASP) algorithm is developed by utilizing the reported information on prior active users. The proposed CVASP is a highly practical algorithm that does not require any prior knowledge of the number of active users or the noise level, as the cross validation technique could properly determine the stopping condition. Extensive simulation results demonstrate that the proposed mechanism could achieve almost the same performance as compared to the existing state of art CS-based multiuser detection algorithms while eliminating the need for any prior knowledge.

DNN offloading has become an important supporting technology for edge intelligence. However, most of the existing works do not consider thread scheduling, which can achieve the parallelism of multiple threads in the practical distributed DNN inference system. To address this issue, we discuss the thread scheduling of the computing units participating in offloading in this paper, considering a single-core Central Processing Unit (CPU) and the Round Robin Scheduling (RRS). We deduce the relationship between the blocking of DNN inference-related threads and the Average Task Delay (ATD) and prove that an appropriate buffer setting can reduce blocking times. Theoretical analysis verifies that the buffering mechanism (DBM) can reduce the ATD significantly, and experimental results demonstrate that the DBM-improved DNN offloading can achieve a delay reduction of 14%-71%.

With the massive use of GPU, task scheduling under CPU-GPU clusters has become an indispensable research topic. Unlike existing models, we propose an innovative framework that users offload their tasks in CPU-GPU heterogeneous Edge Clusters (ECs) instead of general-purpose CPU clusters. The framework takes full advantage of the GPU's powerful parallel computing capabilities. Specifically, we decompose each user task into sequential segments and parallel segments, which can be offloaded to CPUs and GPUs of the ECs, respectively. By dis-cretizing the GPU's computing capability, we formulate a Mixed Integer Nonlinear Programming (MINLP), which involves jointly optimizing the task offloading decision, the uplink transmission power of users, and computing resource allocation. To tackle this challenging problem, we propose a Joint Simulated Annealing and Convex Optimization (JSAC) based algorithm to minimize the total overhead consisting of delay and energy consumption. Our experimental simulation results demonstrate that the JSAC algorithm can make full use of GPU's powerful parallel computing capability via allocating GPU resources effectively. In particular, the JSAC algorithm achieves optimal performance in terms of system overhead, number of beneficial UEs, and speedup.

To cope with the high communication overhead caused by frequent aggregation of Federated Learning (FL) in Multi-access Edge Computing (MEC) scenarios, Hierarchical Federated Edge Learning (HFEL) is proposed as an evolving framework. HFEL offloads tasks to edge servers for partial model aggregation to reduce network traffic. However, most of the existing research focuses on resource optimization for HFEL without considering the impact of data characteristics and cannot guarantee the quality of FL training. To this end, we propose a task offloading approach based on data and resource heterogeneity under HFEL to improve training performance and reduce system cost. Specifically, we leverage information entropy to incorporate data statistical features into the cost function to reshape edge datasets. In addition, we applied Multi-Agent Deep Deterministic Policy Gradient (MADDPG) with a resource allocation module to generate distributed offloading policy more efficiently. Our algorithm not only adopts local observations to obtain the optimal action but also takes into account device heterogeneity, which can adapt to the unstable edge environment. Extensive experiments under multiple datasets and baselines are carried out, which demonstrate that our algorithm can effectively improve the accuracy of aggregated models while reducing system cost.

Partitioning and offloading the deep neural network (DNN) model over multi-tier computing units have been recently proposed to shorten the inference time. However, the state-of-the-art cannot adapt to large-scale offloading problems for streaming tasks because of its exponential complexity. Besides, as an essential kind of DNNs, the offloading of grouped con-volutional neural networks (GCNNs) has not been explored yet. Motivated by the above facts, in this paper, we concentrate on the offloading of chained DNNs (CDNNs) and GCNNs for streaming tasks. Consider a typical heterogeneous network consisting of various computing units, the user equipment (UE) publishes computation-intensive and delay-sensitive streaming DNN tasks while computing units accomplish them collaboratively. To mini-mize the delay of processing the task stream, DNN layers should be offloaded to appropriate units, which is the streaming-task multi-unit (STMU) problem. To tackle this problem, we formulate a non-cooperative potential game called unit competition of layers (UCL). The theoretical analysis proves the existence of the Nash equilibrium (NE), and the corresponding algorithm with linear complexity is developed to achieve the NE. Finally, extensive experiments demonstrate that UCL outperforms the state-of-the-art significantly in large-scale scenarios while maintaining similar performance on small-scale tasks.

A fundamental issue in multiaccess edge computing (MEC) is efficiently offloading multiple tasks to multiple helper nodes (MTMH), i.e., MEC servers. However, most of the existing decentralized schemes do not consider interuser interference or merely adopt time division multiple access (TDMA) as the multiple access scheme for MTMH in the heterogeneous scenario, leading to a large latency. To address these issues, we propose DOT, a novel Decentralized Offloading of Tasks scheme in orthogonal frequency division multiple access (OFDMA)-based heterogeneous MEC, to minimize the sum cost in terms of energy consumption and delay. Specifically, we first formulate DOT as an optimization problem considering the interuser interference and dynamics in communication and computation resource allocation. Then, considering the huge dimension of potential offloading decisions and conflicting objectives of different users, the total cost of each user is minimized in a distributed manner by modeling the offloading problem as a potential game. The formulated potential game is proved to be an ordinal potential game and thus admits a Nash equilibrium (NE). Further, we develop an offloading algorithm to achieve the NE by exploiting the finite improvement property. Finally, simulation results demonstrate that DOT can achieve a lower cost compared with other baselines.

Incentive mechanisms are essential for stimulating adequate worker participation to achieve good truth discovery performance in mobile crowdsensing (MCS) systems. However, most of existing incentive mechanisms only consider compensating workers’ sensing cost, while the cost incurred by potential privacy leakage has been largely neglected. Moreover, none of existing privacy-preserving incentive mechanisms has incorporated workers’ different privacy preferences to provide personalized payments for them. In this paper, we propose a contract-based personalized privacy-preserving incentive mechanism for truth discovery in MCS systems, named Paris-TD, which provides personalized payments for workers as a compensation for privacy cost while achieving accurate truth discovery. The basic idea is that the platform offers a set of different contracts to workers with different privacy preferences, and each worker chooses to sign a contract which specifies a privacy-preserving degree (PPD) and the corresponding payment the worker will receive if she submits perturbed data with that PPD. Specifically, we respectively design a set of optimal contracts analytically under both full and incomplete information models, which maximize the truth discovery accuracy under a given budget, while satisfying the individual rationality and incentive compatibility properties. The feasibility and effectiveness of Paris-TD are validated through experiments on both synthetic and real-world datasets.

In 5G massive multiple input multiple output (MIMO) system, the main challenges to mitigate inter-cell interference (ICI) are overhead of information exchange and computational complexity. In this paper, we propose an interference approximation method based on spatial features, which can cover the major channel information by low overhead. And based on this method, a novel distributed low-complexity interference coordination algorithm called SFDIC is proposed, which is based on the idea of leader-follower game to avoid strong ICI. The experimental results show that the proposed interference approximation method is strongly consistent with the traditional channel matrix based interference calculation method on the trend, whose correlation coefficient is 0.9098 and Kullback-Leibler (KL) divergence is close to 0. In low and medium-speed scenarios, the SFDIC increases system and edge throughput by more than 20% and 107% than joint space division multiplexing (JSDM) respectively. And these scenarios reduce the sharing overhead by more than 50% simultaneously. In addition, the new channel predicted module based on Koopman operator is incorporated to improve practical feasibility and system performance loss causing by delay for the first time.

Considering the contradiction between limited re-sources in small devices and the high complexity of deep neural networks (DNNs), DNNs can hardly run on small devices such as smartphones and wearable devices. Therefore, offloading DNNs to computing units (fog/edge servers), where each unit executes a part of a DNN collaboratively, has gained increasing popularity. Notably, DNNs are generally in chained structure, while streaming tasks are the central part of artificial-intelligent applications. Thus it is crucial to reduce chained DNNs' delay for streaming tasks. Although existing works have advanced DNN offloading largely, the discussion about chained DNNs and streaming tasks is negligible. To address this issue, in this paper, we propose a layer-level offloading model called OCDST based on the analysis about them. After chained DNNs are offloaded to computing units, the involved units will handle streaming tasks as a pipeline. Consequently, the model significantly reduces the average task delay by paralleling each step in the pipeline. Moreover, the global optimal model solution is drawn by an improved depth-first search (DFS) algorithm, which utilizes DFS to achieve path establishment, calculation and record stages. Based on multi-threading programming and producer-consumer pattern, a program parallelization scheme is also devised to ensure the feasibility of the obtained optimum. Experimental results show that OCDST significantly outperforms recent works with higher inferring speed and faster response.

Feedback mechanism has been widely used in wireless communication such as channel equalization and resource allocation. In recent years, deep learning (DL) has made great progress in the field of wireless communication. There is now some work that attempts to introduce plain feedback mechanisms into DL algorithm to solve wireless communication problems. However, the improvement of plain feedback DL methods is limited in complex situations due to those methods lack sufficient learning ability on feedback information. In this paper, we propose a Multi-Agent Feedback Enabled Neural Network (MAFENN) equalizer, which consists of a specific learnable feedback agent and two feed-forward agents. Three fully cooperative intelligent agents help the system improve the ability to remove wireless inter-symbol interference (ISI) in receiving ends. We further formulate it into a three-player Stackelberg Game, which helps us to optimize and train this model more efficiently. To verify the feasibility of our proposed MAFENN system and the Stackelberg Game optimization, we conduct a series of experiments to compare the symbol error rate (SER) performance of the MAFENN equalizer and the other methods which utilizes quadrature phase-shift keying (QPSK) modulation scheme. Our performance outperforms that of the other equalizers at different signal-to-noise ratio (SNR) settings for both linear and nonlinear channels.

High overhead of sharing and feedback and high computational complexity are common problems in multi-cell processing. In this paper, a novel framework for bidirectional signal transformation between space and frequency domains of massive MIMO channels is proposed to reduce system processing overhead and complexity. We design new space and frequency features and build the framework by two off-line trained neural networks (NN). Moreover, the uniqueness of spatial features is proved. Average errors of uni- and bi-directional transformation are 7.6% and 7.3%. When applying the framework to inter-cell interference coordination (ICIC), the system and edge throughput are both increased compared to the traditional scheme with low information sharing overhead.

Exploiting the sparse nature of user activity, compressed sensing (CS) has been a powerful technique to realize efficient user detection in grant-free nonorthogonal multiple access (NOMA). However, most of the existing CS-based multiuser detection schemes merely independently incorporate the temporal correlation in frame-based transmission or spatial correlation induced by multiantenna reception, leading to unsatisfactory user detection performance. Driven by the observation in the CS theory that the signal recovery performance could be enhanced by an increased number of sparse vectors with a common support set, in this article, we propose a novel joint user activity identification and channel estimation (JUICE) framework by integrating the temporal correlation of active user sets with multiantenna reception, which could achieve superior user detection performance. Specifically, we first formulate the JUICE as a Kronecker CS (KCS) problem to model the CS measurement process, by fully extracting the spatial-temporal structure of user activity. Then, based on the mined spatial-temporal structure of user activity, an adaptive subspace pursuit algorithm is developed, i.e., spatial-temporal structure enhanced adaptive subspace pursuit (STS-ASP), which could realize efficient multiuser detection. A distinct advantage of the proposed algorithm is that it does not require any prior knowledge (e.g., the number of active users and the noise level), by adaptively acquiring the number of active users and employing the cross-validation technique to appropriately terminate the iterative procedures. Extensive experimental evaluation is conducted, and the results corroborate the superiority of the proposed framework compared with the existing CS-based multiuser detection methods.

Federated learning (FL) is a privacy-preserving distributed machine learning framework, which involves training statistical models over a number of mobile users (i.e., workers) while keeping data localized. However, recent works have demonstrated that workers engaged in FL are still susceptible to advanced inference attacks when sharing model updates or gradients, which would discourage them from participating. Most of the existing incentive mechanisms for FL mainly account for workers’ resource cost, while the cost incurred by potential privacy leakage resulting from inference attacks has rarely been incorporated. To address these issues, in this paper, we propose a contract-based personalized privacy-preserving incentive for FL, named Pain-FL, to provide customized payments for workers with different privacy preferences as compensation for privacy leakage cost while ensuring satisfactory convergence performance of FL models. The core idea of Pain-FL is that each worker agrees on a customized contract, which specifies a kind of privacy-preserving level (PPL) and the corresponding payment, with the server in each round of FL. Then, the worker perturbs her calculated stochastic gradients to be uploaded with that PPL in exchange for that payment. In particular, we respectively derive a set of optimal contracts analytically under both complete and incomplete information models, which could optimize the convergence performance of the finally learned global model, while bearing some desired economic properties, i.e., budget feasibility, individual rationality, and incentive compatibility. An exhaustive experimental evaluation of Pain-FL is conducted, and the results corroborate its practicability and effectiveness.

Truth discovery is an effective tool to unearth truthful answers in crowdsourced question answering systems. Incentive mechanisms are necessary in such systems to stimulate worker participation. However, most of existing incentive mechanisms only consider compensating workers' resource cost, while the cost incurred by potential privacy leakage has been rarely incorporated. More importantly, to the best of our knowledge, how to provide personalized payments for workers with different privacy demands remains uninvestigated thus far. In this paper, we propose a contract-based personalized privacy-preserving incentive mechanism for truth discovery in crowdsourced question answering systems, named PINTION, which provides personalized payments for workers with different privacy demands as a compensation for privacy cost, while ensuring accurate truth discovery. The basic idea is that each worker chooses to sign a contract with the platform, which specifies a privacy-preserving level (PPL) and a payment, and then submits perturbed answers with that PPL in return for that payment. Specifically, we respectively design a set of optimal contracts under both complete and incomplete information models, which could maximize the truth discovery accuracy, while satisfying the budget feasibility, individual rationality and incentive compatibility properties. Experiments on both synthetic and real-world datasets validate the feasibility and effectiveness of PINTION.

It is a fundamental issue to achieve efficient information collection in Internet of Things (IoT), where random (channel) access plays an indispensable role, especially when coordination among IoT end nodes is unachievable. Compressive sensing (CS) has been widely used in random access to facilitate energy efficient and accurate data collection. However, a joint sparsity structure, which commonly exists among signals acquired by different end nodes, has been long ignored by existing CS-based random access schemes, leading to insufficient energy efficiency and accuracy. In this article, capitalizing on this joint sparsity structure, we propose a structured compressive random access (SCRA) mechanism in order to achieve maximum energy efficiency with accuracy guarantee for data collection. Specifically, we first model the data loss induced by packet collisions during random access as an independent CS measurement process for each node, where the corresponding CS projection matrix is determined by the data loss pattern. Furthermore, in order to control the amount of data transmitted in the channel and alleviate the packet collisions, we employ the concept of sensing probability to perform random subsampling at each end node before transmission, where the optimal sensing probability is derived. Finally, we propose to jointly recover the set of original signals at all nodes based on the concept of group sparsity by formulating the data collection process as a single-measurement-vector problem in CS. The evaluation results validate the effectiveness of SCRA in utilizing the joint sparsity structure to obtain superior performance compared to the benchmark methods.

Radio-frequency identification (RFID) has pervasive applications in building ultralow-power ubiquitous networks, where backscatter communication during tag identification is neither reliable nor efficient. Inspired by the sparsity that only a few RFID tags communicate with the reader simultaneously, many compressed sensing (CS)-based schemes have been proposed to exploit the colliding tag responses to facilitate efficient tag identification. However, most of them suffer from huge ID search space and signature collision during the CS recovery process. To address these issues, we propose SCRIC, a novel sparsity-controlled RFID identification scheme using a random signature assignment, which achieves a faster and more robust identification performance. Specifically, to tackle identification failure caused by severe signature collision, we assign each active tag an access probability to control the sparsity and reduce signature collision. Theoretical analysis is given to prove that the signature collision probability of the proposed scheme is reduced compared with the existing random signature scheme and an optimal access probability is derived. Moreover, considering that conventional CS recovery algorithm relies heavily on the unpractical assumption that the active tag number is known precisely in advance, we integrate the cross validation (CV) into CS recovery algorithms and propose a greedy algorithm called the CV-based orthogonal matching pursuit (OMP-CV), which can reduce the tag identification false alarm rate without any prior knowledge. Extensive experimental results show that the proposed mechanism significantly outperforms the existing CS-based tag identification methods in terms of identification speed and robustness to noise.

In this work, compressive sensing (CS) is applied to facilitate efficient wireless information transmission over lossy communication links. Inherently sparse data packets are transmitted without compression or error protection. The packet loss during transmission is modeled as a random sampling process of the transmitted data. The original signal then is reconstructed based on correctly received data packets using CS-based reconstruction method. No computations for source, channel coding or random measurement sampling will be required at the transmitter side. Thus, this method is suitable for applications where transmitters have extreme low power constraints such as wireless sensor networks. Compared with traditional error protection technique(automatic repeat request, data interleaving and interpolation), the proposed method delivers higher quality of sparse signal while significantly reducing energy consumption at transmitter as well as transmission latency.

We present AWSAN, a adjustable wireless sensor array network based target monitoring system. It is universal for different scenarios and convenient for deploymen- t. A compressed sampling scheme is introduced to greatly reduce the data exchange volume, moving most processing load to fusion center. It provides similar performance to the traditional wireless or fixed array while using low-cost & low-power nodes.