Lianfen Huang

Design and implementation of wireless Smart-home sensor network based on ZigBee protocol

We propose a system of wireless smart-home sensor network based on ZigBee and PSTN remote control using PIC18LF4620 SCM and 2.4G RF transceiver module. The network configuration, communication protocol, software and hardware implementation process of our system are described in this paper. Through using the PSTN network for the long-haul network and ZigBee technology for the indoor network, our system fulfils home-remote-control and auto-alarm, expediently.

Sparsity-Based Spatial Interpolation in Wireless Sensor Networks

In wireless sensor networks, due to environmental limitations or bad wireless channel conditions, not all sensor samples can be successfully gathered at the sink. In this paper, we try to recover these missing samples without retransmission. The missing samples estimation problem is mathematically formulated as a 2-D spatial interpolation. Assuming the 2-D sensor data can be sparsely represented by a dictionary, a sparsity-based recovery approach by solving for l1 norm minimization is proposed. It is shown that these missing samples can be reasonably recovered based on the null space property of the dictionary. This property also points out the way to choose an appropriate sparsifying dictionary to further reduce the recovery errors. The simulation results on synthetic and real data demonstrate that the proposed approach can recover the missing data reasonably well and that it outperforms the weighted average interpolation methods when the data change relatively fast or blocks of samples are lost. Besides, there exists a range of missing rates where the proposed approach is robust to missing block sizes.

Anti-PUE Attack Based on Joint Position Verification in Cognitive Radio Networks

Cognitive Radio (CR) has been regarded as one of the options to solve the problem of low spectrum utilization. However, security problems of CR networks limit its applications. Most of the proposed security schemes are aiming at the location verification for incumbent transmitter, such as the verification technologies of Distance Ratio Test (DRT) and Distance Difference Test (DDT), but all of these methods have certain shortcomings. In this paper, a joint position verification method is proposed to enhance the positioning accuracy. Simulation results show that our method is simple and achieves high accuracy on transmitter location verification in CR network, which can improve the ability to resist PUE attack.

A sensing policy based on the statistical property of licensed channel in cognitive network

Many spectrum usage measurement reports have shown that the fixed-frequency allocation mechanism causes unbalanced resource occupancy. Most of the current sensing policies assume the same utilisation rate for various channels. Therefore, their performance cannot be optimised in the presence of sensing constraints. This paper proposes a modified sensing policy based on the statistical property of licensed channels. Using the negotiation rule and the statistics sensing results for the perception phase, the proposed approach can always select the licensed channels with the lowest statistical occupation number. The probability statistics approach is used to formulate the proposed sensing policies for the saturation network. Both analytical and simulation results are presented to validate the proposed model. The results show that our proposed sensing policy can maintain sensing efficiency without adding constraints and also guarantee that more available licensed channels are available. In addition, the computational cost, i.e., sensing number and time, can be reduced. We conclude that our proposed sensing policy can make full use of spectrum resources to improve network throughput.

On Selfish Behavior in Wireless Sensor Networks: A Game Theoretic Case Study

In this paper, we study the selfish behavior in wireless sensor networks and apply a game theory method to address this problem in a CSMA/CA protocol. More specifically, we formulate the Media Access Control (MAC) layer activity in sensor networks as an optimization problem in terms of the random accessing problem. Then we propose a distributed algorithm for the system to reach the Nash Equilibrium (NE). We have de-fined a Contention Window Select Game (CWSG) in which each sensor selects its own contention window to control the access probability. This approach can improve the average performance, compared to a random strategy with each sensor selecting its own window independently. We prove the unique existence of NE in the CWSG, and propose a penalizing mechan-ism based on repeated game to prevent the non-cooperative selfish behavior of decreasing the contention window without per-mission.

A PHY-layer Authentication Approach for Transmitter Identification in Cognitive Radio Networks

Cognitive radio (CR) was proposed as the key technologies to achieve the secondary usage of the spectrum. The security problems of CR networks have not been intensively studied, such as the primary user emulation (PUE) attacks. In this paper, we study the non-interactive security issues for wireless networks and propose a physical layer authentication approach to prevent PUE attacks in CR networks. We extract transmitter location fingerprints from the wireless medium in the multipath propagation environment. Wavelet transform is used to extract the characteristics of these fingerprints. Simulation and experiment results show that our approach can identify the PUE attackers and the legitimate primary users effectively.

Layered security approach in LTE and simulation

The Third Generation Partnership Project (3GPP) has been specifying the standards of Long Term Evolution (LTE) for 3G radio access. The security concerns in wireless networks might have prevented its further widespread adoption. Layered security approach in LTE is analyzed, an EAP method EAP-Archie used for authentication and ciphering is introduced in this paper. EAP-Archie which embedded in Open Diameter environment is simulated. The result shows it can authentication successfully.

MHC-MAC: Cognitive MAC with asynchronous-assembly line mode for improving spectrum utilization and network capacity

National Natural Science Foundation of China [61172097]; National Science Council of Taiwan [NSC99-2219-E-197-001, NSC99-2219-E-197-002]

Sparsity-Based Online Missing Data Recovery Using Overcomplete Dictionary

Estimating missing sample values is an inherent problem in sensor network applications. In wireless sensor networks, due to power outage at a sensor node, hardware dysfunction, or bad environmental conditions, not all sensor samples can be successfully gathered at the sink. Additionally, in the context of data streams, some nodes may continually miss samples for a period of time. To address these issues, a sparsity-based online data recovery approach is proposed in this paper. First, we construct an overcomplete dictionary composed of past data frames and traditional fixed transform bases. Assuming the current frame can be sparsely represented using only a few elements of the dictionary, missing samples in each frame can be estimated by basis pursuit. If some delay is acceptable, the estimation of the current frame can be further improved by leveraging the observation from the next frames. Our method was tested on data from a real sensor network application, monitoring the temperatures of the disk drive racks at a data center. Simulations show that in terms of estimation accuracy and stability, the proposed approach outperforms existing average-based interpolation methods, and is more robust to burst missing along the time dimension.

Transient fingerprint feature extraction for WLAN cards based on polynomial fitting

With the rapid development of cognitive radio network (CRN), the information security has become a primary concern. In this paper, transient fingerprinting is incorporated into CRN for detecting Primary User Emulation (PUE) attacks. A novel approach is proposed to extract transient fingerprint feature of transmitters. The energy envelope obtained from the instantaneous signal by spectrogram analysis, is fitted according to the least square estimation. The polynomial coefficients are selected as the feature vectors of instantaneous signal. A data acquisition system is designed to capture IEEE802.11b signals in the 2.4GHz ISM band. The results of data analysis indicate that it greatly improves the performance of detecting different brand of WLAN cards.