nils-herrmann/clean_scirepeval huggingface dataset:
On Relay Nodes Deployment for Distributed Detection in Wireless Sensor Networks

In this paper, the problem of deploying relay nodes in wireless sensor networks will be considered. A system consisting of a set of sensor nodes communicating to a fusion center, where decisions are made, is considered. Based on our system model assumptions, some sensor nodes will provide "less- informative" measurements to the fusion center about the state of nature; we consider relay nodes deployment in the sensor network instead of the less-informative sensor nodes to forward the measurements of the other, "more-informative" sensor nodes. This introduces a new tradeoff in the system design between the number of measurements sent to the fusion center and the reliability of the more-informative measurements, which is enhanced by deploying more relay nodes in the network. We will analyze the performance of two protocols over Rayleigh flat-fading channels. In Protocol I, each sensor node directly transmits its measurement to the fusion center. In Protocol II, relay nodes will be used instead of the less-informative sensor nodes to forward the measurements of the more-informative sensor nodes. Hence, in Protocol II, the reliability of the more-informative measurements is enhanced at the expense of having fewer measurements sent to the fusion center and this creates the tradeoff between the number of measurements available at the fusion center and the reliability of the measurements.
Power optimized space-time code for layer coded multimedia over wireless channels

A power optimized space-time code is presented for reliable delivery of layer coded multimedia, data through wireless channels. Appropriate power control further improves the performance of space time coding. By allocating transmitted power according to the layer perceptual importance, unequal error protection is achieved. Numerical example shows that the proposed algorithm achieves 6 dB PSNR improvement compared to that with equal power distribution in low SNR range.
A scalable multicast key management scheme for heterogeneous wireless networks

Secure multicast applications require key management that provides access control. In wireless networks, where the error rate is high and the bandwidth is limited, the design of key management schemes should place emphasis on reducing the communication burden associated with key updating. A communication-efficient class of key management schemes is those that employ a tree hierarchy. However, these tree-based key management schemes do not exploit issues related to the delivery of keying information that provide opportunities to further reduce the communication burden of rekeying. In this paper, we propose a method for designing multicast key management trees that match the network topology. The proposed key management scheme localizes the transmission of keying information and significantly reduces the communication burden of rekeying. Further, in mobile wireless applications, the issue of user handoff between base stations may cause user relocation on the key management tree. We address the problem of user handoff by proposing an efficient handoff scheme for our topology-matching key management trees. The proposed scheme also addresses the heterogeneity of the network. For multicast applications containing several thousands of users, simulations indicate a 55%-80% reduction in the communication cost compared to key trees that are independent of the network topology. Analysis and simulations also show that the communication cost of the proposed topology-matching key management tree scales better than topology-independent trees as the size of multicast group grows.
Multiuser cross-layer resource allocation for video transmission over wireless networks

With the advancement of video-compression technology and the wide deployment of wireless networks, there is an increasing demand for wireless video communication services, and many design challenges remain to be overcome. In this article, we discuss how to dynamically allocate resources according to the changing environments and requirements, so as to improve the overall system performance and ensure individual quality of service (QoS). Specifically, we consider two aspects with regard to design issues: cross-layer design, which jointly optimizes resource utilization from the physical layer to the application layer, and multiuser diversity, which explores source and channel heterogeneity for different users. We study how to efficiently transmit multiple video streams, encoded by current and future video codecs, over resource-limited wireless networks such as 3G/4G cellular system and future wireless local/metropolitan area networks (WLANs/WMANs)
Performance analysis for pilot-embedded data-bearing approach in space-time coded MIMO systems

This paper evaluates the performance of the data-bearing approach for pilot-embedding for joint data detection and channel estimation in space-time (ST) coded MIMO systems. Performance measures, such as the MMSE of channel estimation, Cramer-Rao lower bound (CRLB), and the Chernoff's bound of the estimated-channel bit error rate (BER) for ST codes, are explored to examine the proposed scheme. The power allocation problem for data and pilot parts is also addressed by optimizing the probability-of-error upper-bound (PEUB) mismatched factor subject to certain constraints. Three kinds of data bearer and pilot structures are investigated via simulations, including time-multiplexing (TM)-based, ST-block-code (STBC)-based, and code-multiplexing (CM)-based data bearer and pilot matrices. Among these three structures, the CM-based scheme provides superior detection performance over the TM-based and the STBC-based schemes for nonquasistatic flat Rayleigh fading channels, while the performances of these three structures are quite close for quasi-static flat Rayleigh fading channels.
Combating Strong–Weak Spatial–Temporal Resonances in Time-Reversal Uplinks

In a time-reversal (TR) communication system, the signal-to-noise ratio (SNR) is boosted and the inter-user interference (IUI) is suppressed due to the spatial-temporal resonances, commonly known as the focusing effects, of the TR technique when implemented in a rich scattering environment. However, since the spatial-temporal resonances highly depend on the location-specific multipath profile, there exists a strong-weak spatial-temporal resonances effect. In the TR uplink system, different users at different locations enjoy different strengths of spatial-temporal resonances, i.e., the received signal-to-interference-noise ratios (SINRs) for different users vary, and the weak ones can be blocked from correct detection in the presence of strong ones. In this paper, we formulate the strong-weak spatial-temporal resonances in the multiuser TR uplink system as a max-min weighted SINR balancing problem by joint power control and signature design. Then, a novel two-stage adaptive algorithm that can guarantee the convergence is proposed. In stage I, the original nonconvex problem is relaxed into a Perron Frobenius eigenvalue optimization problem and an iterative algorithm is proposed to obtain the optimum efficiently. In stage II, the gradient search method is applied to update the relaxed feasible set until the global optimum for the original optimization problem is obtained. Numerical results show that our algorithm converges quickly, achieves a high energy-efficiency, and provides a performance guarantee to all users.
Fingerprint multicast in secure video streaming

Digital fingerprinting is an emerging technology to protect multimedia content from illegal redistribution, where each distributed copy is labeled with unique identification information. In video streaming, huge amount of data have to be transmitted to a large number of users under stringent latency constraints, so the bandwidth-efficient distribution of uniquely fingerprinted copies is crucial. This paper investigates the secure multicast of anticollusion fingerprinted video in streaming applications and analyzes their performance. We first propose a general fingerprint multicast scheme that can be used with most spread spectrum embedding-based multimedia fingerprinting systems. To further improve the bandwidth efficiency, we explore the special structure of the fingerprint design and propose a joint fingerprint design and distribution scheme. From our simulations, the two proposed schemes can reduce the bandwidth requirement by 48% to 87%, depending on the number of users, the characteristics of video sequences, and the network and computation constraints. We also show that under the constraint that all colluders have the same probability of detection, the embedded fingerprints in the two schemes have approximately the same collusion resistance. Finally, we propose a fingerprint drift compensation scheme to improve the quality of the reconstructed sequences at the decoder's side without introducing extra communication overhead.
Full-rate full-diversity space-frequency codes with optimum coding advantage

A general space-frequency (SF) block code structure is proposed that can guarantee full-rate (one channel symbol per subcarrier) and full-diversity transmission in multiple-input multiple-output-orthogonal frequency-division multiplexing (MIMO-OFDM) systems. The proposed method can be used to construct SF codes for an arbitrary number of transmit antennas, any memoryless modulation and arbitrary power-delay profiles. Moreover, assuming that the power-delay profile is known at the transmitter, we devise an interleaving method to maximize the overall performance of the code. We show that the diversity product can be decomposed as the product of the "intrinsic" diversity product, which depends only on the used signal constellation and the code design, and the "extrinsic" diversity product, which depends only on the applied interleaving method and the power delay profile of the channel. Based on this decomposition, we propose an interleaving strategy to maximize the "extrinsic" diversity product. Extensive simulation results show that the proposed SF codes outperform the previously existing codes by about 3-5 dB, and that the proposed interleaving method results in about 1-3-dB performance improvement compared to random interleaving.
Algorithm and VLSI architecture for high performance adaptive video scaling

We propose an efficient high-performance scaling algorithm based on the oriented polynomial image model. We develop a simple classification scheme that classifies the region around a pixel as an oriented or nonoriented block. Based on this classification, a nonlinear oriented interpolation is performed to obtain high quality video scaling. In addition, we also propose a generalization that can perform scaling for arbitrary scaling factors. Based on this algorithm, we develop an efficient architecture for image scaling. Specifically, we consider an architecture for scaling a Quarter Common Intermediate Format (QCIF) image to 4CIF format. We show the feasibility of the architecture by describing the various computation units in a hardware description language (Verilog) and synthesizing the design into a netlist of gates. The synthesis results show that an application specific integrated circuit (ASIC) design which meets the throughput requirements can be built with a reasonable silicon area.
Achieving Centimeter-Accuracy Indoor Localization on WiFi Platforms: A Multi-Antenna Approach

Channel frequency response (CFR) is a fine-grained location-specific information in WiFi systems that can be utilized in indoor positioning systems (IPSs). However, CFR-based IPSs can hardly achieve an accuracy at the centimeter level due to the limited bandwidth in WiFi systems. To achieve such accuracy using WiFi devices, we propose an IPS that fully harnesses the spatial diversity in multiple-input–multiple-output WiFi systems, which leads to a much larger effective bandwidth than the bandwidth of a WiFi channel. The proposed IPS obtains CFRs associated with locations-of-interest on multiple antenna links during the training phase. In the positioning phase, the IPS captures instantaneous CFRs from a location to be estimated and compares it with the CFRs acquired in the training phase via the time-reversal resonating strength with residual synchronization errors compensated. Extensive experiment results in an office environment with a measurement resolution of 5 cm demonstrate that, with a single pair of WiFi devices and an effective bandwidth of 321 MHz, the proposed IPS achieves detection rates of 99.91% and 100% with false alarm rates of 1.81% and 1.65% under the line-of-sight (LOS) and non-LOS (NLOS) scenarios, respectively. Meanwhile, the proposed IPS is robust against environment dynamics. Moreover, experiment results with a measurement resolution of 0.5 cm demonstrate a localization accuracy of 1–2 cm in the NLOS scenario.
Maximizing Network Capacity with Optimal Source Selection: A Network Science Perspective

How to enhance the network capacity is one of the most important issues. To achieve this, the existing works have focused on improving either the network structure or routing strategies with a common assumption of uniformly distributing the replicas of information among the nodes in the network. The nodes associated with information replicas are considered as source nodes (or server). However, for many networks such as the Internet, some nodes have much more traffics than the others, exhibiting an asymmetric phenomenon. In this letter, we study the optimal source selection strategy to enhance the network capacity, where an optimization model is proposed to find the optimal source selection probability distribution. Simulation results show that in homogeneous networks, most of the nodes can be the sources. While in heterogeneous networks such as the scale-free networks, only a small number of the nodes can be the sources. Moreover, an interesting phenomenon is observed that the optimal proportion of source nodes in Erdös-Rényi random network and Barabási-Albert scale-free network exhibits a power law relationship with the network size.
A Distributed Relay-Assignment Algorithm for Cooperative Communications in Wireless Networks

A crucial challenge in the implementation of a cooperative diversity protocol is how to assign source-relay pairs. In this paper, we address this problem under the knowledge of the users' spatial distribution and we propose a distributed relay-assignment algorithm for cooperative communications. In the proposed algorithm, the relay is chosen to be the nearestneighbor to the user towards the base-station (access-point). An outage analysis for the proposed scheme is provided under a random spatial distribution for the users, and an approximate expression for the outage probability is derived. Simulation results for indoor wireless local area networks (WLAN) are provided. By utilizing the proposed protocol, simulation results indicate a significant gain in coverage area over the direct transmission scheme under fairly the same bandwidth efficiency and fixed average transmitted power. A 350% increase in the coverage area can be achieved by the distributed Nearest-neighbor protocols. This coverage increase can also be translated to energy efficiency over direct transmission when fixing the total coverage area.
Cooperation Enforcement in Autonomous MANETs under Noise and Imperfect Observation

In autonomous mobile ad hoc networks (MANET) where each user is its own authority, the issue of cooperation enforcement must be solved first to enable network functioning, such as packet forwarding, which becomes very difficult under noise and imperfect monitoring. In this paper, we focus on cooperation enforcement in autonomous mobile ad hoc networks under noise and imperfect observation and study the basic packet-forwarding function using the repeated game models with imperfect information. A belief-based packet forwarding framework is proposed to obtain cooperation-enforcement strategies solely based on each node's own past actions and its private imperfect observation of other nodes' information. The simulation results illustrate that the proposed belief-based packet forwarding approach can enforce the cooperation with only a small performance degradation compared with the unconditionally cooperative outcomes when noise and imperfect observation exist
JET: Dynamic Join-Exit-Tree Amortization and Scheduling for Contributory Key Management

In secure group communications, the time cost associated with key updates in the events of member join and departure is an important aspect of quality of service, especially in large groups with highly dynamic membership. To achieve better time efficiency, we propose a join-exit-tree (JET) key management framework. First, a special key tree topology with join and exit subtrees is introduced to handle key updates for dynamic membership. Then, optimization techniques are employed to determine the capacities of join and exit subtrees for achieving the best time efficiency, and algorithms are designed to dynamically update the join and exit trees. We show that, on average, the asymptotic time cost for each member join/departure event is reduced to O(log(logn)) from the previous cost of O(logn), where n is the group size. Our experimental results based on simulated user activities as well as the real MBone data demonstrate that the proposed JET scheme can significantly improve the time efficiency, while maintaining low communication and computation cost, of tree-based contributory key management
Joint power control and signature design for time-reversal uplinks

In the time reversal division multiple access (TRDMA) system, the signal-to-noise ratio (SNR) is boosted and the inter-user interference (IUI) is suppressed due to the temporal and spatial focusing effects of the time-reversal (TR) technique. However, since the focusing effects highly depend on the location-specific multipath profile, there exists a strong-weak focusing effect in the TRDMA uplink system where different users at different locations enjoy different level of focusing effects. In this paper, we formulate the strong-weak focusing effect in the multiuser TRDMA uplink system as a max-min signal-to-interference-noise ratio (SINR) balancing problem by means of joint power control and signature filter design. A novel two-stage adaptive algorithm that can guarantee the convergence is proposed. Numerical results show that our algorithm converges quickly, achieves a high energy-efficiency gain, and provides a performance guarantee to all users.
Cheat-proof cooperation strategies for wireless live streaming social networks

Multimedia social network analysis is an emerging research area, which analyzes the behavior of users who share multimedia content and investigates the impact of human dynamics on multimedia systems. Users watching live streaming in the same wireless network share the same backbone connection to the Internet, thus they might want to cooperate with each other to obtain better video quality. These users form a wireless live-streaming social network and every user wishes to watch video with as high as possible quality while paying as less as cost for cooperation. Thus full cooperation cannot be guaranteed and the cooperation strategy must give incentives to the users. This paper proposes a game-theoretic framework to model user behavior and designs incentive-based strategies to stimulate user cooperation in wireless live streaming. We analyze the Pareto optimality and time-restricted bargaining equilibrium of the game. We also take into consideration selfish users' cheating behavior and propose cheat-proof strategies. Both our analytical and simulation results show that the proposed strategies can effectively stimulate user cooperation, achieve cheat free and help provide reliable services.
Cooperative communications with partial channel state information: When to cooperate?

In this paper we propose a new cooperative protocol, which takes into consideration the partial channel state information (CSI) available at the source. With such protocol a significant improvement in the transmission rate can be achieved in decode-and-forward cooperative transmission, while guaranteeing full diversity order. We derive closed-form expressions for the transmission rate and the symbol error rate (SER) for the M-PSK and the M-QAM signalling. Moreover, we consider two optimization metrics in the protocol design to enhance the system performance; the first is based on minimizing the SER only, while the second is based on minimizing a joint function of both the SER and the transmission rate. Finally, the obtained analytical results are verified through computer simulations
A pattern classification framework for theoretical analysis of component forensics

Component forensics is an emerging methodology for forensic analysis that aims at estimating the algorithms and parameters in each component of a digital device. This paper proposes a theoretical foundation to examine the performance limits of component forensics. Using ideas from pattern classification theory, we define formal notions of identifiability of components in the information processing chain. We show that the parameters of certain device components can be accurately identified only in controlled settings through semi non-intrusive forensics, while the parameters of some others can be computed directly from the available sample data via complete non-intrusive analysis. We then extend the proposed theoretical framework to quantify and improve the accuracies and confidence in component parameter identification for several forensic applications.
Feasibility of transmit diversity for IS-136 TDMA systems

In this paper, we investigate the performance of transmit diversity technique operating in IS-136 TDMA systems where the Doppler frequency can be as high as 184 Hz. Transmit diversity transforms a flat fading channel into a frequency selective fading channel, thus we use finite length decision feedback equalizers to estimate the desired signal at the receiver. The channel parameters are trained via the training symbols and tracked using decision-directed symbols. It is shown that systems with transmit diversity can provide a significant performance improvement over systems without transmit diversity for Rayleigh flat fading channels when the Doppler frequency is less than 40 Hz; however for systems with high Doppler frequency, transmit diversity alone cannot totally mitigate the fast fading effect since the effects of the channel estimation errors may cancel the benefit of the transmit diversity.
Throughput Analysis for Cooperation in Random Access Networks

This paper aims at answering the questions of how to enable cooperative communications in random access networks. And, since cooperation introduces extra transmissions in the channel, what are the benefits and possible tradeoffs associated with cooperation? To achieve this goal, a novel cooperative protocol for wireless networks based on IEEE 802.11 random access protocol is proposed. The proposed protocol guarantees an uncontested channel access to the relay. Interaction between different network nodes is characterized and performance analysis is conducted through Markov chain models in conjunction with queueing theoretical analysis. Results demonstrate significant gains in terms of throughput and delay performance compared with the non cooperative CSMA/CA protocol.