Zhetao Li

A green and reliable communication modeling for industrial internet of things

An improved protocol (HTP) is proposed through combining SW-ARQ and NCRT scheme.HTP protocol is a strategy which can optimize multiple performances at the same time.HTP protocol is proved to improve lifetime above 15% under same reliability.HTP protocol is proved to improve reliability by 10%45% under same lifetime.HTP protocol is more practicality which allows low complexity implementation. Green and reliable communication has great significance for Industrial Internet of Things. Unfortunately, because of the loss nature, achieving reliable transmission is challenging. In this paper, a novel hybrid transmission protocol (HTP) is proposed to maximize lifetime while the reliability is still guaranteed. The proposed protocol adopts Send-Wait automatic Repeat-Request protocol in hotspot areas to reduce the energy consumption and network coding based redundant transmission approach with adaptive redundancy level in non-hotspot areas to guarantee the reliability. The proposed protocol could improve the lifetime and shorten the delay on the premise of ensuring the reliability. Comparing with Send-Wait automatic Repeat-Request protocol, it can improve lifetime by 15%30% under the same reliability and improve the reliability by 12%45% under the same lifetime. Comparing with network coding based redundant transmission approach, the lifetime has increased by more than one time under the same reliability. Display Omitted

FFSC: An Energy Efficiency Communications Approach for Delay Minimizing in Internet of Things

It is desirable for alarm packets to be forwarded to the sink as quickly as possible in wireless sensor networks. In this paper, we initially analyze the theory of the relationships between network configurations and network lifetime as well as transmission delay. Then, we propose an approximate optimization approach to minimize the end-to-end delay with a reduced complexity of configuration under the condition that the network lifetime remains greater than the specified target value. A local forwarding approach named Fast data collection for nodes Far away from the sink and slow data collection for nodes Close to the Sink (FFSC) is proposed. This approach is energy efficient. Moreover, it can further reduce the end-to-end delay. Both the comprehensive theoretical analysis and the experimental results indicate that the performance of FFSC is better than the methods proposed by previous studies. Relative to the direct forwarding strategy, the FFSC approach can reduce the delay by 7.56%-23.16% and increase the lifetime by more than 25%. It can also increase the energy efficiency as much as 18.99%. Relative to the single fixed threshold strategy, the FFSC approach can reduce the delay by 4.16%-9.79% and increase the energy efficiency by 19.28% while still guaranteeing the same lifetime as those previous methods.

Energy-Efficient Broadcasting Scheme for Smart Industrial Wireless Sensor Networks

In smart Industrial Wireless Sensor Networks (IWSNs), sensor nodes usually adopt a programmable technology. These smart devices can obtain new or special functions by reprogramming: they upgrade their soft systems through receiving new version of program codes. If sensor nodes need to be upgraded, the sink node will propagate program code packets to them through “one-to-many” broadcasting, and therefore new capabilities can be obtained, forming the so-called Software Defined Network (SDN). However, due to the high volume of code packet, the constraint energy of sensor node, and the unreliable link quality of wireless network, rapidly broadcasting the code packets to all nodes in network can be a challenge issue. In this paper, a novel Energy-efficient Broadcast scheme with adjustable broadcasting radius is proposed aiming to improve the performance of network upgrade. In our scheme, the nonhotspots sensor nodes take full advantage of their residual energy caused in data collection period to improve the packet reception probability and reduce the broadcasting delay of code packet transmission by enlarging the broadcasting radius, that is, the transmitting power. The theoretical analyses and experimental results show that, compared with previous work, our approach can averagely reduce the Network Upgrade Delay (NUD) by 14.8%–45.2% and simultaneously increase the reliability without harming the lifetime of network.

APMD: A fast data transmission protocol with reliability guarantee for pervasive sensing data communication

Abstract In pervasive sensing data communication systems, it is significant to ensure data reliably and rapidly sent to the control center. Otherwise, laggard data transmission may result in vital loss. An adaptive persistent m data (APMD) transmission protocol is proposed to reduce delay with reliability guarantee for pervasive sensing data communication systems. In APMD transmission protocol, each data packet is sent for m ( m ≥ 1 ) times by sender at the first time of transmission. If the data packet cannot be received successfully for m times, sender will transmit this data packet again and wait for ACK sent back by receiver in the send and wait way. The next data packet will not be sent until this packet is sent successfully or the time of transmission reaches the maximum limit. The option of appropriate value of m is based on the energy situation, which guarantees high network lifetime. Both theoretical analysis and experimental simulation results indicate that the APMD protocol is better than the previous data transmission protocol. The delay can be reduced by 12.73%–14.78%, the energy utilization rate can be improved by about 35% compared to the SW-ARQ protocol, while the reliability increases slightly and the lifetime has no difference.

A low latency, energy efficient MAC protocol for wireless sensor networks

Reducing unnecessary and redundant handshake frame is considered as a promising way to reduce the end-to-end delay and energy consumption. Here, a protocol named compressed handshake media access control (CH-MAC) is presented. CH-MAC introduces a new handshake mechanism with implicit RTS to achieve the object of low delivery latency and an initiative sleeping mechanism to settle the hidden terminal problem. Simulation results show that the proposed protocol outperforms SMAC protocol in both energy consumption and packet latency.

Distributed cooperative communication nodes control and optimization reliability for resource-constrained WSNs

Abstract The utilization of distributed control and optimization is still a challenge issue to achieve reliable communication for resource-constrained networked systems. In this paper, a distributed cooperative communication nodes control (DCCNC) approach is proposed to achieve higher reliability communication and longer network lifetime for resource-constrained wireless sensor network (WSNs). A DCCNC scheme adopts feedback control approach to determine the appropriate number of node which participates in cooperative communication according to the application reliability requirements. A residue energy notification mechanism is used to notice the minimum residual energy of nodes in a network, then the number of cooperative communication nodes is adjusted according to the difference between the residual energy of nodes and the minimum residual energy of network. In a DCCNC scheme, larger number of participate cooperative communication nodes are adopted in non-hotspots area to achieve high reliability, while less number of participate cooperative communication nodes are adopted in hotspots area to achieve high network lifetime. The theoretical analysis and experimental results show that comparing with previous communications schemes, DCCNC scheme can reduce end to end Data Fail delivering Ratio (DFR) by 57.16–93.29% while retaining network lifetime, and DCCNC approach can also improves lifetime by 3.89–18.75% while retaining weighted end to end (DFR).

A Trust-Based Model for Security Cooperating in Vehicular Cloud Computing

VCC is a computing paradigm which consists of vehicles cooperating with each other to realize a lot of practical applications, such as delivering packages. Security cooperation is a fundamental research topic in Vehicular Cloud Computing (VCC). Because of the existence of malicious vehicles, the security cooperation has become a challenging issue in VCC. In this paper, a trust-based model for security cooperating, named DBTEC, is proposed to promote vehicles’ security cooperation in VCC. DBTEC combines the indirect trust estimation in Public board and the direct trust estimation in Private board to compute the trust value of vehicles when choosing cooperative partners; a trustworthy cooperation path generating scheme is proposed to ensure the safety of cooperation and increase the cooperation completion rates in VCC. Extensive experiments show that our scheme improves the overall cooperation completion rates by 6~7%.

A throughput aware with collision-free MAC for wireless LANs

创新点本文结合CSMA/CA与TDMA思想的方式,通过利用节点在网络中能感知到其他节点成功传输的特点,使节点选取在上一个虚拟TDMA周期中是第i个成功发送数据的顺序作为在当前虚拟TDMA周期中的发送顺序。由于同一时隙有且仅有一个成功传输的节点,那么所有成功传输的节点都有一个独立的时隙来发送数据,未成功的节点则随机选取剩余的时隙中某一个再次发送数据。这样成功节点间的数据发送不会相互干扰,未成功节点也不会影响到成功节点的传输。并且在一个虚拟TDMA周期中,当所有节点都能成功发送一次数据时就能一直延续下去,实现免碰撞从而获得高吞吐量。

Informed Spectrum Discovery in Cognitive Radio Networks using Proactive Out-of-Band Sensing

Cognitive radio (CR) users, known as secondary users (SUs), should avoid interference with primary users (PUs) who own the licensed band, while trying to access it; when the licensed band is unused by the PUs. To detect PUs, spectrum sensing should be performed over in-band channels that are currently in use by SUs. If PUs return to access the band, SUs need to vacate it, disrupting the SUs’ communication unless a non-utilized band is discovered. Obtaining a non-utilized band in a short period facilitate seamless communication for SUs and avoid interference on PUs by vacating from the channel immediately. Searching for a non-utilized band can be done through proactive out-of-band (OB) sensing. In this paper, we suggest a proactive OB sensing scheme that minimizes the time required to discover a non-utilized spectrum in order to continue communication. Although, the duration spent on OB sensing reduces the throughput of the CR networks that can be achieved on band being utilized, the lost throughput can be compensated in the new discovered band. We demonstrate that, the effect of our proposed scheme on the throughput owing to OB sensing is insignificant, while exhibiting a very short channel discovery time.

Compressed Sensing Based on Best Wavelet Packet Basis for Image Processing

In this paper, an algorithm named best wavelet packet tree decomposition (BWPTD) is proposed for image compression. In order to obtain better sparse representation of image, best wavelet packet basis is introduced to decompose image signal in the algorithm. Experimental results show that BWPTD is better than single layer wavelet decompression (SLWD) and original compressed sensing (OCS) in peak signal to noise ratio (PSNR) by 2db and 8db, respectively. In addition, the reconstruction time of BWPTD is only half as that of SLWD and OCS.