Abstract:In the Internet of Things, location information is considered as not only one of the basic elements of sensing information collected by sensors but also an essential prerequisite for providing location based services. On the one hand, location information can facilitate people's lives, but on the other hand, such information exposure may cause great harm to the users. The location privacy preservation for Internet of Things has become one of the hottest topics in the academic world. This paper first states the objectives and challenges of achieving location privacy preservation for the Internet of Things. Then, it provides an overview on the location privacy leakages and the corresponding privacy preserving techniques in localization, location based services and side information. Finally, it discusses the future directions on location privacy preservation for the Internet of Things.

Abstract:In heterogeneous wireless sensor networks, a strong relation exists among different types of data being composed into an event. Energy consumption can be reduced by collecting partial data to approximately detect the event. A node scheduling problem for approximate event detection is proposed. The nodes in the network are organized into subsets that are activated successively. The lifetime of the network is maximized on the condition that the partial data collected can be formed as an approximation of the event. The node scheduling problem for approximate event detection is proved to be NP-complete. A greedy-based approximate algorithm is devised with 1/2 as the approximate ratio. The experimental results illustrate that the lifetime of the network can be prolonged effectively.

Abstract:Wireless body area network (WBAN) is a network of wearable or implanted sensors around or inside human body. In 2012, the IEEE 802.15 Working Group developed a new communication standard IEEE 802.15.6 specifically for WBAN. The primary medium access control technique defined in this standard for narrow-band communication is slotted CSMA/CA mechanism supporting differentiated QoS service. To understand the intrinsic nature of this mechanism, the backoff procedure under saturation condition is modeled by Markov chain so that throughput, successful packet delivery rate, and delay are analyzed. Simulation results confirm the accuracy of the model analysis. Both analysis and simulation results show that this standard provides differentiated service for different priorities, however, also indicates that under saturation condition the medium is mostly preempted by the highest priority while starving other priorities.

Abstract:This paper proposes an array receiving scheme for ultra-wideband (UWB) OFDM signals in WSN networks. The major feature of the proposed scheme is recovering the UWB OFDM signal by frequency stitching. Firstly, the UWB OFDM signal is divided into multiple sub-bands. Every two adjacent sub-bands share at least one overlapped subcarrier(s), which is used for time alignment later. A sub-signal of the UWB OFDM signal is received on each sub-band by a narrow-band receiver. The received data sets of narrow-band receivers are time aligned by performing peak value alignment retrieval (PVAR) on the shared subcarriers. Then the UWB OFDM signal is recovered by fusing the received data sets according to the result of PVAR. As the implementation of narrow-band receivers only needs low-speed ADCs, the challenge of high-speed ADC in traditional UWB OFDM receiver is addressed. Extensive simulations are performed to demonstrate the validity of the proposed scheme and further look into three performance metrics: (1) synchronization error-tolerance, (2) extensibility, (3) performance under different SNR values.

Abstract:In order to overcome the shortcomings of underwater sensor network communication security and the characteristics of the underwater acoustic communication channel, this paper proposes a secure hierarchical hybrid encryption communication protocol based on quantum teleportation for underwater sensor network. For the first layer in the communication of the surface station and autonomous underwater vehicle (AUV), the method achieves shared key transmission in the onshore sink and AUV by the application of quantum teleportation to ensure the security of the communication information by quantum nonlocality. For the second layer in the AUV and UW-sensor, it attains the underwater node to the autonomous underwater vehicle transmission information encryption using symmetric encryption algorithms to improve the efficiency of the communication by using the symmetric key. The paper analyzes quantum attack, classical attack and communication efficiency, and the proposed protocol can effectively prevent quantum intercepted attack, quantum reconstructive attack and quantum replacement attack.

Abstract:Aiming to accomplish continuous and reliable communication of cognitive radio sensor network (CRSN) in the licensed band, this paper proposes a novel CRSN architecture by combing the strategies of cooperative sensing and wideband sensing. Through deploying cognitive nodes that are especially responsible for spectrum sensing in the network, spectrum sensing and data transmission are reasonably separated. While maximizing the duration of sensing and transmission, the scheme also achieves real-time spectrum sensing and continuous data transmission, significantly improving the probability of detection and network throughput. In addition, the design organizes the cognitive nodes to cooperatively perform multi-channel joint detection on the wideband. In this way, besides improving the detection reliability, the CRSN can continuously access the licensed band to further ensure that the data transmission is successive. The average network throughput under different hard fusion rules is analyzed and compared through simulations. Results show that the proposed network architecture can achieve higher throughput.

Abstract:Wireless ad hoc networks suffer from link unreliability and high packet loss rate. To reduce the number of sending data packets in unreliable multihop wireless networks, a network coding based routing protocol with path switching, NCPS, is proposed. To ensure the paths are suitable for network coding, this study first analyzes the sufficient conditions that paths in wireless network can be encoded and decoded. Next, it analyzes the coding gain with path switching in contrast to the traditional optimal routing algorithm. Finally, in order to optimize the data packet transmission times in wireless networks, it proposes a routing protocol which combines path switching and network coding. Experimental results show that under different environmental parameters of networks, NCPS can reduce the number of data transmission in network effectively and obtain stable coding gain.

Abstract:Based on the received signal strength (RSS) range measurement technology, and by utilizing the sampling and filtering approach of MCL-kind particle filtering localization algorithms in mobile sensor networks (MSN), a kind of signal strength resolution for dynamic localization based on sampling and filtering (SSR-SF) which integrates with the principle of strength resolution and composition in physics is proposed. In the produced rectangular coordinates, SSR-SF resolves the resultants the signal vectors between mobile node, beacon nodes, and samples and beacon nodes respectively. It samples from an error annulus, compares the signal resultant vectors of the samples with that of the mobile node, and then picks out the final samples whose resultant vectors' mood are closest to that of the mobile node. SSR-SF takes the average value of those final samples' coordinates as the mobile node's location. Simulation results show that, under the same experiment conditions, the localization accuracy of SSR-SF is clearly higher than its counterparts and it needs no additional hardware.

Abstract:Urban VANETs will be an important part of intelligent transportation in the future as it provides an effective solution to solve the city traffic problem. Most of the existing routing schemes have low performance on efficiency and reliability, because they can't solve the problems of high speed mobility, complex city traffic environment and different traffic density. Focusing on the urban environment of signal propagation and traffic pattern with red-light stops and fixed and cyclic bus route, this article proposes a layered urban vehicle ad-hoc network routing protocol model on mobility support in public transportation. The model transfers the complex and uncertain routing protocol model between the vehicles to collaborative and definitive three layered routing, taking advantages of the fixed bus route to optimize communication between ordinary vehicles and buses with the cluster head strategy. Mechanism of single-hop selection is provided according to the signal propagation attenuation model and vehicle mobility model, and mechanism of multi-hop forwarding is given based on delay probability. The resulted design can ensure the reliability and efficiency on bus-assistant forwarding. A cluster trigger strategy capable of adapting to the vehicle density is also presented. The simulation results show that the whole scheme can achieve good data delivery and low delay with sufficient hops.

Abstract:Based on probabilistic sensing model, this paper investigates the issue of barrier coverage in order to solve the problem of barrier coverage in wireless sensor network. By analyzing the cost and the power consumption of sensor nodes and adopting the data fusion technique within adjacent nodes, the paper brings forth an optimized deployment strategy for barrier coverage when the speed of mobile target is lower than the critical speed. It also presents the critical condition for the strategy to apply. The analysis and simulation results show that the proposed strategy can effectively improve the lifetime of the network.

Abstract:To tackle the issue of interval sensitivity in the application of WSN data collection based on the prediction mechanism of fitting curve, this paper proposes fitting curve similarity sequence based on time periods to transform data collection problem based on prediction into the similarity estimation under certain accuracy. Feature-Based similarity is assumed to obey the Gaussian distribution. By studying the maximum probability of accurate prediction of perceived similarity, the proposed method uses Greedy algorithm to dynamically adjust the predicted similarity. Finally, it uses PSO algorithm to achieve inference of the predicted data based on predicted similarity. Simulation results show that this algorithm has achieved the desired results, and also provides great improvement in terms of energy consumption.

Abstract:To address the problems of transmission delay, transmission conflicts and low throughput in Wireless sensor networks, this paper proposes a channel allocation and routing strategy in Multi-Radio Multi-Channel Networks. The strategy is to dynamically establish a k-ary n-cube topology. It not only uses the optimal static channel allocation algorithm to improve the throughput of nodes but also employs the dimension order routing algorithm to reduce transmission conflicts. This method is suitable for the network of density nodes with many communication conflicts. It can also be used in both single hop and multi hop network environment. The experiment results show that compared with traditional methods, the channel allocation and routing strategy based on the k-ary n-cube topology can effectively reduce end to end delay, network conflicts and energy consumption, prolong the network lifetime and increase the throughput of network.

Abstract:Privacy preservation has attracted more and more attentions in wireless sensor networks. It is a challenge to provide precise Skyline query result while preserving data privacy in wireless sensor networks. This paper proposes a privacy-preserving Skyline query protocol in two-tiered sensor networks (PPSQ). Using Z-O encoding and hash-based message authentication code mechanism, this protocol to allows storage node to attain tuple relations of domination judgment without the sensory data plaintext, and therefore protects privacy of sensory data. In addition, assisted computing node calculates the verification code to ensure the integrity of the query result. Theoretical analysis and experimental results show that the PPSQ can guarantee the privacy of sensory data and the integrity of query result, and it also has better performance than the previous work in skyline query processing.

Abstract:In WSN (wireless sensor network), the security of message transmission is needed. GTMS (group-based trust management scheme) guarantees the security of routing by node trust. However, its description of trust is too simple to represent the complexity of the entity. Hence, based on the comparison method of cloud similarity, this paper establishes a node trust, and proposes a new routing protocol CRPCTMAS (cluster reliability protocol based on cloud trust model and the ant scheme). The performance analysis show that, based the correct judgment of node trust, CRPCTMAS can find a security route not only to guarantee the high ratio of data packet emission but also to prolong the lifetime of the network.

Abstract:Resilience has become one of the most important indicators in evaluating the topological structure of wireless sensor networks. How to construct a robust topology of WSNs is even more important. Based on complex networks theory, a topology evolution model—DEDA, which considers the node degree, the remaining energy and the transmission distance, is proposed. Some resilience metrics are introduced to analyze the resilience of WSNs and computer simulations are performed to compare the resilience of several topologies that are generated with different growth models. The experimental results show that DEDA model provides better resilience against both random and deliberate attacks.

Abstract:To address the application scenarios of cluster based or multiple sink based wireless sensor networks, this paper proposes a Top-|K| query based distributed data reconstruction method which includes the distributed iterative hard thresholding algorithm and the dual thresholds based distributed Top-|K| query algorithm. The administrative node and member nodes run the distributed iterative hard thresholding algorithm, realizing the iterative hard thresholding algorithm in a distributed manner at the same time. Meanwhile, the administrative node and member nodes run the dual thresholds based distributed Top-|K| query algorithm which can query the Top-|K| sum of the elements in the result of the previous algorithm in a distributed manner as well. Experimental result show that the proposed method can achieve the same data reconstruction performance as the existing methods. Furthermore, it can also decrease the transmitted data number and interactive time between the administrative node and member nodes.