nils-herrmann/clean_scirepeval huggingface dataset:
Game Theoretic Analysis of Cooperation Stimulation and Security in Autonomous Mobile Ad Hoc Networks

In autonomous mobile ad hoc networks, nodes belong to different authorities and pursue different goals; therefore, cooperation among them cannot be taken for granted. Meanwhile, some nodes may be malicious, whose objective is to damage the network. In this paper, we present a joint analysis of cooperation stimulation and security in autonomous mobile ad hoc networks under a game theoretic framework. We first investigate a simple yet illuminating two-player packet forwarding game and derive the optimal and cheat-proof packet forwarding strategies. We then investigate the secure routing and packet forwarding game for autonomous ad hoc networks in noisy and hostile environments and derive a set of reputation-based cheat-proof and attack-resistant cooperation stimulation strategies. When analyzing the cooperation strategies, besides Nash equilibrium, other optimality criteria, such as Pareto optimality, subgame perfection, fairness, and cheat-proofing, have also been considered. Both analysis and simulation studies have shown that the proposed strategies can effectively stimulate cooperation among selfish nodes in autonomous mobile ad hoc networks under noise and attacks, and the damage that can be caused by attackers is bounded and limited
Interference-mitigating broadband secondary user downlink system: A time-reversal solution

The spatial and time focusing effects of time-reversal technology make it an ideal candidate for the low interference downlink system to relieve the coexistence issues among different wireless communication systems. The transmitting power would be concentrated at the intended receiver and the leakage to unintended receivers would be automatically suppressed. In this paper, a time-reversal based secondary user downlink system with the coexistence of primary users is proposed. The primary user's performance loss is investigated in terms of effective SINR degradation and achievable data rate deduction. It is illustrated through numerical examples that the time-reversal downlink system relieves the primary user's performance loss as well as achieves satisfying power efficiency compared with the traditional direct transmission.
An auction-based framework for multimedia streaming over cognitive radio networks

Recently, many works have been proposed in the area of cognitive radio to efficiently utilize the spectrum for data communication. However, little effort has been made in content-aware multimedia applications over cognitive radio networks. In this paper, we study the multimedia streaming problem over cognitive radio networks. The uniquely scalable and delay-sensitive characteristics of multimedia data and the resulting impact on users' viewing experiences of multimedia content are explicitly involved in the utility functions, due to which the primary user and the secondary users can seamlessly switch among different quality levels to achieve the greatest utilities. Then, we formulate the spectrum allocation problem as an auction game and propose a distributively auction-based spectrum allocation scheme, which is spectrum allocation using Alternative Ascending Clock Auction (ACA-A). We prove that ACA-A is cheat-proof and can maximize the social welfare. Finally, simulation results are presented to demonstrate the efficiency of the proposed algorithms.
Self-Learning Repeated Game Framework for Distributed Primary-Prioritized Dynamic Spectrum Access

Dynamic spectrum access has become a promising approach to fully utilize the scarce spectrum resources. In a dynamically changing spectrum environment, it is very important to design a distributed access scheme that can coordinate different users' access adapt to spectrum dynamics with only local information. In this paper, we propose a self-learning repeated game framework for distributed primary-prioritized dynamic spectrum access through modeling the interactions between secondary users as a noncooperative game. With the proposed framework, the inefficiency due to users' selfish behavior can be highly improved, and the secondary users can distributively obtain their optimal access probabilities with only local observations. The simulation results show that the proposed framework can achieve comparable performances with those of the centralized primary-prioritized dynamic spectrum access scheme.
Characterizing performance of multiband UWB systems using Poisson cluster arriving fading paths

This paper provides a novel performance formulation for UWB systems that successfully captures the unique multipath-rich property and random-clustering phenomenon of UWB channels. Using the Saleh-Valenzuela model, we are able to characterize the pairwise error probability (PEP) performance for UWB systems employing multiband OFDM based on cluster arrival rate, ray arrival rate within a cluster, and cluster and ray decay factors. In addition, a PEP approximation technique is established, which allows us to obtain a closed-form PEP formulation that provides insightful understanding of the effect of channel characteristics on the performances of UWB systems. Finally, simulation results are provided to support the theoretical analysis.
Noncooperative power-control game and throughput game over wireless networks

Resource allocation is an important means to increase system performance in wireless networks. In this letter, a game-theory approach for distributed resource allocation is proposed. Observing the bilinear matrix inequality nature of resource allocation, we construct two interrelated games: a power-control game at the user level, and a throughput game at the system level, respectively, to avoid local optima. An optimal complex centralized algorithm is developed as a performance bound. The simulations show that the proposed games have near-optimal system performance.
Time-reversal with limited signature precision: Tradeoff between complexity and performance

The success of time-reversal (TR) technique relies on the design of TR signature from the multi-path profile. In practice, the signature is of limited precision instead of being infinite due to the finite resolution in hardware. Such limited signature precision will degrade the TR focusing effect and thus the system performance. Although several works have been proposed to study the performance of TR system with one-bit signature, a general relation between the resolution of signature and the system performance has not been established to answer the question: how many bits are needed for TR systems to achieve desirable system performance? In the paper, we address the question by studying the TR system with limited signature precision. We derive theoretically the relationship between the received signal-to-interference-plus-noise ratio (SINR) and the quantization step. Through simulations, we find that for a typical TR system, 4-bit resolution for the signature is good enough to achieve good system performance.
Advances in cognitive radio networks: A survey

With the rapid deployment of new wireless devices and applications, the last decade has witnessed a growing demand for wireless radio spectrum. However, the fixed spectrum assignment policy becomes a bottleneck for more efficient spectrum utilization, under which a great portion of the licensed spectrum is severely under-utilized. The inefficient usage of the limited spectrum resources urges the spectrum regulatory bodies to review their policy and start to seek for innovative communication technology that can exploit the wireless spectrum in a more intelligent and flexible way. The concept of cognitive radio is proposed to address the issue of spectrum efficiency and has been receiving an increasing attention in recent years, since it equips wireless users the capability to optimally adapt their operating parameters according to the interactions with the surrounding radio environment. There have been many significant developments in the past few years on cognitive radios. This paper surveys recent advances in research related to cognitive radios. The fundamentals of cognitive radio technology, architecture of a cognitive radio network and its applications are first introduced. The existing works in spectrum sensing are reviewed, and important issues in dynamic spectrum allocation and sharing are investigated in detail.
On Cost-Effective Incentive Mechanisms in Microtask Crowdsourcing

While microtask crowdsourcing provides a new way to solve large volumes of small tasks at a much lower price compared with traditional inhouse solutions, it suffers from quality problems due to the lack of incentives. On the other hand, providing incentives for microtask crowdsourcing is challenging since verifying the quality of submitted solutions is so expensive that it will negate the advantage of microtask crowdsourcing. We study cost-effective incentive mechanisms for microtask crowdsourcing in this paper. In particular, we consider a model with strategic workers, where the primary objective of a worker is to maximize his own utility. Based on this model, we first analyze two basic mechanisms and show their limitations in collecting high-quality solutions with low cost. Then, we propose a cost-effective mechanism that employs quality-aware worker training as a tool to stimulate workers to provide high-quality solutions. We prove theoretically that the proposed mechanism can be designed to obtain high-quality solutions from workers and ensure the budget constraint of the requester at the same time. Beyond its theoretical guarantees, we further demonstrate the effectiveness of our proposed mechanisms through a set of behavioral experiments.
On analysis of wireless uplink using analog network coding with non-coherent modulations

Analog network coding (ANC) has been widely used in wireless uplink to improve throughput and provide spatial diversity. However, the receiver has to estimate the channel coefficients of all users to perform coherent detection, thus the signaling overhead is sometimes formidable and may even outweigh the performance gain. To reduce the channel estimation overhead, we study non-coherent modulations in this work with emphasis on receiver design and performance analysis. Depending on channel state information, we first develop the coherent, partial coherent and non-coherent receivers based on maximum likelihood (ML) principle. As the ML non-coherent receiver has a non-tractable integral form, we further propose two suboptimum receivers depending on the relative quality of source-relay channel and relay-destination channel.We also study the pairwise error probability, and show that full diversity is still achievable at high signal-to-noise ratios using non-coherent modulations; however, the error rate decreases much slower than that of coherent systems due to the incapability to efficiently suppress multi-user interferences. Extensive simulations are also given to verify our analytical results.
Securing dynamic group membership information over multicast: attacks and immunization

In secure multicast communications, key management is employed to prevent unauthorized access to the multicast content. Key management, however, can disclose the information about the dynamics of the group membership to inside attackers, which is a potential threat to many multicast applications. In this paper, we investigated several attack strategies for stealing group dynamic information and demonstrated their effectiveness through simulations. Further, we proposed an anti-attack technique utilizing batch rekeying and phantom users, and derived performance criteria describing the security level of the proposed scheme. The proposed anti-attack scheme was evaluated based on the membership data obtained from real MBone sessions.
Realizing Massive MIMO Effect Using a Single Antenna: A Time-Reversal Approach

Massive MIMO has shown the great potential in improving the achievable rate with a very large number of antennas. However, several critical challenges in designing the analog front-end and coordinating the large-scale antenna array have to be carefully addressed. Does there exist an alternative that can achieve similar system performance to massive MIMO with a simpler design? In this paper, we show that by using time-reversal approach, with a sufficiently large bandwidth, one can harvest massive multipaths naturally existing in the rich-scattering environment to form a large number of virtual antennas to achieve the desired massive MIMO effect with a single antenna. We analyze the expected achievable rate of the time- reversal system with MMSE waveform. Furthermore, the corresponding asymptotic achievable rate under a massive multipath setting is derived. Experiment result based on real channel measurements shows that, even with only a single antenna, the time- reversal wideband system can achieve comparable performance as the massive MIMO system in terms of expected achievable rate.
WLC37-2: An Efficient Cooperative Protocol for Multiuser-OFDM Networks

In this paper, we propose a relay-based scheme where a fixed number of relays are utilized to design a OFDM cooperative protocol. By exploiting limited feedback from the destination such that each relay is able to help forward information of multiple sources in one OFDM symbol, the proposed cooperative protocol not only achieves full diversity but also efficiently utilizes available bandwidth. A practical relay assignment scheme is also proposed to specify the pairing of sources and relays in cooperative networks. The outage probability analysis of the proposed cooperative protocol is provided, and the analytical results are validated via computer experiments. Moreover, a closed-form lower bound on the outage probability of any relay-assignment schemes is established to provide a performance benchmark of the proposed cooperative protocol. Based on the outage probability analysis, the optimum relay location for the proposed relay-assignment scheme is determined.
Wavelet-based multiresolution local tomography

We develop an algorithm to reconstruct the wavelet coefficients of an image from the Radon transform data. The proposed method uses the properties of wavelets to localize the Radon transform and can be used to reconstruct a local region of the cross section of a body, using almost completely local data that significantly reduces the amount of exposure and computations in X-ray tomography. The property that distinguishes our algorithm from the previous algorithms is based on the observation that for some wavelet bases with sufficiently many vanishing moments, the ramp-filtered version of the scaling function as well as the wavelet function has extremely rapid decay. We show that the variance of the elements of the null-space is negligible in the locally reconstructed image. Also, we find an upper bound for the reconstruction error in terms of the amount of data used in the algorithm. To reconstruct a local region 16 pixels in radius in a 256x256 image, we require 22% of full exposure data.
Anti error propagation methods for wireless uplink using network coding

Wireless network coding suffers the error propagation issues that may severely degrade the diversity performance. In this work, we develop two power scaling schemes at the relay side and two detection schemes at the receiver side, respectively, to mitigate error propagation in network-coded uplink channel and thus achieve full diversity. For the soft power scaling based link adaptive relaying, we develop a virtual channel model and demonstrate that the relay power should be such to balance the signal-to-noise ratios of the source-relay channel and relay-destination channel. As for the hard power scaling based ON-OFF relaying, we first design a decision rule based on total pairwise error probability, and then simplifies it to the threshold-based relaying strategy. At the receiver side, we show that the weighted minimum distance detection with the weight being determined by the relative link quality of source-relay channel and relay-destination channel can achieve full diversity once the global channel state information is available, otherwise the maximum likelihood detection that explicitly takes into account relay decoding error should be employed to achieve full diversity.
Indirect Reciprocity Security Game for Large-Scale Wireless Networks

Radio nodes can obtain illegal security gains by performing attacks, and they are motivated to do so if the illegal gains are larger than the resulting costs. Most existing direct reciprocity-based works assume constant interaction among players, which does not always hold in large-scale networks. In this paper, we propose a security system that applies the indirect reciprocity principle to combat attacks in wireless networks. Because network access is highly desirable for most nodes, including potential attackers, our system punishes attackers by stopping their network services. With a properly designed social norm and reputation updating process, the aim is to incur a cost due to the loss of network access to exceed the illegal security gain. Thus rational nodes are motivated to abandon adversary behavior for their own interests. We derive the optimal strategy and the corresponding stationary reputation distribution, and evaluate the stability condition of the optimal strategy using the evolutionarily stable strategy concept. This security system is robust against collusion attacks and can significantly reduce the attacker population for a wide range of attacks when the stability condition is satisfied. Simulation results show that the proposed system significantly outperforms the existing direct reciprocity-based systems, especially in the large-scale networks with terminal mobility. This technique can be extended to many wireless networks, including cognitive radio networks, to improve their security performance.
Differential space-frequency modulation via smooth logical channel for broadband wireless communications

In this letter, a differential space-frequency modulation (DSFM) scheme is proposed for multiple input multiple-output (MIMO)-orthogonal frequency-division multiplexing (OFDM) systems in broadband wireless communications. We assume that the fading channels keep constant only within each OFDM block, and may change independently from one OFDM block to another. The differential schemes proposed for MIMO-OFDM systems in the literature cannot successfully decode with such a rapidly fading channel, since the successful decoding of the previously existing schemes relies on the assumption that the fading channel keeps constant within a period of several OFDM blocks, and it changes slowly from a period of several OFDM blocks to another. In our proposed DSFM scheme, the transmitted signals are differentially encoded in the frequency domain within each OFDM block. Thus, the differential decoding can be performed over subcarriers within each single OFDM block. Furthermore, if a statistical channel power-delay profile (PDP) is known at the transmitter, we propose to create a smooth logical channel to improve the performance of the DSFM scheme. We obtain the smooth logical channel by sorting the channel frequency responses over subcarriers from a statistical point of view. If the logical channel is not smooth enough, we further consider a pruning process in which we use only the "good" part of the channel and get rid of the "bad" part of the channel. Simulation results show that the proposed DSFM scheme over a smooth logical channel (with pruning, if necessary) performs well for various channel PDPs.
Interference model and analysis on device-to-device cellular coexist networks

Device-to-device (D2D) communications can enhance the overall system capacity by reusing cellular spectrum, which at the same time leads to severe interference to cellular connections and vice versa. In practice, even when two wireless connections share the same spectrum, the interference between them may not always exist if there is no conflict at packet-level transmissions. Thus, in this paper, we establish a cross-layer model for D2D communications underlaying cellular network to characterize the realistic interference scenario. The closed-form stable throughput region between one D2D pair and one cellular link is deduced. Subsequently, our model is extended to a generalized scenario where multiple D2D pairs share the same resources with one cellular link, in which the upper bound of the stable throughput region is derived. As a consequence, the stable throughput regions are significantly enlarged via the proposed model.
WiBall: A Time-Reversal Focusing Ball Method for Decimeter-Accuracy Indoor Tracking

With the development of the Internet of Things technology, indoor tracking has become a popular application nowadays, but most existing solutions can only work in line-of-sight scenarios, or require regular recalibration. In this paper, we propose WiBall, an accurate and calibration-free indoor tracking system that can work well in non-line-of-sight based on radio signals. WiBall leverages a stationary and location-independent property of the time-reversal focusing effect of radio signals for highly accurate moving distance estimation. Together with the direction estimation based on inertial measurement unit and location correction using the constraints from the floorplan, WiBall is shown to be able to track a moving object with decimeter-level accuracy in different environments. Since WiBall can accommodate a large number of users with only a single pair of devices, it is low-cost and easily scalable, and can be a promising candidate for future indoor tracking applications.
Non-Intrusive Forensic Analysis of Visual Sensors Using Output Images

This paper considers the problem of non-intrusive forensic analysis of the individual components in visual sensors and its implementation. As a new addition to the emerging area of forensic engineering, we present a framework for analyzing technologies employed inside digital cameras based on output images, and develop a set of forensic signal processing algorithms for visual sensors based on color array sensor and interpolation methods. We show through simulations that the proposed method is robust against compression and noise, and can help identify various processing components inside the camera. Such a non-intrusive forensic framework would provide useful evidence for analyzing technology infringement and evolution for visual sensors
Optimization of MANET connectivity via smart deployment/movement of unmanned air vehicles

Unmanned air vehicles (UAVs) can provide important communication advantages to ground-based wireless ad hoc networks. In this paper, the location and movement of UAVs are optimized to improve the connectivity of a wireless network. Four types of network connectivity are quantified: global message connectivity, worst-case connectivity, network bisection connectivity, and k-connectivity. The problems of UAV deployment and movement are formulated to improve the different types of connectivity. Both problems are NP-hard. For the deployment case, some heuristic adaptive schemes are proposed to yield simple but effective solutions. In addition, a closed-form solution for the two-node one-UAV case is provided. For k-connectivity, we propose an algorithm that improves connectivity using Delaunay triangulation. To optimize the UAV movement, an algorithm that tracks changes in the network topology is constructed. The simulation results show that by only deploying a single UAV, the global message network connectivity and the worst-case network connectivity can be improved by up to 109% and 60%, respectively. The network bisection connectivity and the k -connectivity can also be significantly improved.