Deshi Li

The Implementation of Wireless Sensor Network Visualization Platform Based on Wetland Monitoring

In sensor networks concerning about data, data management and representation have become a crucial issue. In this paper, sensor networks deployed to monitor wetland are built with the visualization of their data and topology. The environmental data, such as temperature, humidity, both in atmosphere and soil, illumination intensity and PH around the wetland are sent by the wireless sensor networks to a base station which is connected to the visualization platform on a PC. The approach presented in this paper utilizes serial communication, database management, data and topology visualization to visualize the data gathered by the wireless sensor networks. The data visualization platform can get and display real time information of networks and makes the system convenient to users.

A Distributed and Effective Cluster Routing Protocol of Sensor Networks

Routing protocol is very important in wireless sensor networks (WSNs), which decides the network organization and the route for data transmitting. As many routing protocols have been proposed, they can be divided into hierarchical routing, location-based routing and on-demand routing protocol. Hierarchical routing protocols such as LEACH, PEGASIS can only be used in small scale network; location-based routing protocols are restricted by the geographical information and the nodes must contain GPS equipment; on-demand routing protocols such as AODV can be used in large scale WSNs, but they bring control messages and long delay. This paper proposes a new routing protocol named DECROP (distributed and effective cluster routing protocol). It has following characteristics: It is simple but efficient. It only has a few control messages with high reliability. It also takes clustering and low energy consumption into consideration. DECROP has three processes: initialization, distributed cluster forming, data transmitting and route maintenance. We compare DECROP with AODV, and simulation results indicate that DECROP has fewer control messages, shorter end-to-end delay in the application of transmitting data to base station (BS) and the residual energy is close to AODV. DECROP is especially suitable for large scale WSNs with homogenous sensors.

A Handshake Based Ordered Scheduling MAC Protocol for Underwater Acoustic Local Area Networks

Underwater acoustic local area networks (UA-LANs) can be used to improve the coverage of an underwater network by introducing a tier of local area communications. Media access control (MAC) is a crucial issue for UA-LANs. Existing MAC protocols for terrestrial WLANs cannot be directly applied to UA-LANs due to the acoustic channel features of limited bandwidth and high and variable propagation delay. In this paper, we propose a handshake based ordered scheduling MAC (HOSM) protocol for UA-LANs. The nodes with data packets to be transmitted first reserve the channel in a channel reservation phase. Then an order list is calculated, and the data packets of these nodes are transmitted according to this order list. We develop a control packets transmission adjustment mechanism to reduce collisions of control packets. The key idea of this mechanism is to utilize the information of propagation delay to adjust the time instant of control packets transmitting. To improve channel utilization, we present a variant Max-Min Ant System algorithm to calculate an optimal order for each data transmission round. Simulation results have confirmed that the proposed protocol can achieve high throughput with low delay and good spatial fairness.

An Enhanced IOT Gateway in a Broadcast System

Internet of things (IOT) technology increasingly affects backbone network development. Aiming to reduce or weaken such effects on backbone networks from a traffic perspective and attain no discount on functions in a Cobra Net based digital broadcast system, an enhanced IOT gateway and its evaluation system are presented. Based on the prototype evaluation system, experiments demonstrate the IOT gateway not only inherits the conventional functions previously often carried out by a PC platform or a server, but also develops additional abilities to cut down traffic under some cases and provides portable management for the system at the same time. According to the experimental results, it is possible from a traffic perspective to design an enhanced IOT gateway to provide value added service such as file transfer, message function, etc. in addition to high quality audio service by taking advantage of the verified sub-linear information addition mechanism. Such enhanced gateway can be properly adapted to other kinds of applications according to the non-demanding system requirements of the prototype evaluation system and proposed IOTGW design.

A Priority Based Dynamic Adaptive Routing Protocol for Wireless Sensor Networks

Wireless sensor networks (WSNs) are becoming a viable tool for many monitoring applications. In many cases these applications may be of critical nature where the transmitting of vital information from sensors to base station or sink is crucial, and data loss cannot be tolerated. As a result, the information transmission of wireless sensor networks has various different requirements in performance, such as real-time, reliability and delay. Traditional ad hoc network routing protocols are lack of a priority scheduling routing selection strategy, and are mainly based on the condition ldquoshortest pathrdquo, so after the load increase to a certain extent, a vital packet may be dropped in order to send an ordinary message. To this point, across-layer design method is used to present a new routing protocol which is named as priority based dynamic adaptive routing (PDAR), PDAR uses a priority scheduling adaptive routing mechanism to improve the reliability of sending a packet with high priority and the performance of WSNs. Simulation results show that PDAR significantly decreases end-to end delays by 40.3% and packet loss ratio by 15.3% for high-priority flows without starvation of ordinary traffic, which performs much better than dynamic source routing (DSR) protocol.

Architecture of Underwater Acoustic Sensor Networks: A Survey

Recently, there has been a growing interest in monitoring aqueous environments using underwater acoustic sensor network (UASNs), which is considered as a novel tool in exploring ocean also in small aqueous environments such as lakes, rivers. Network topology is a crucial factor in determining energy consumption, capacity and reliability of a network, its necessary for us to know the feasible architectures and their characteristics of UASNs. In this paper, we do a survey on the architecture of UASNs, and classify the architecture into three groups using the node characters as a rule. We also analyze the open questions should to be faced in further research works. The architecture of USANs would be important for application network design, topology control, communication protocols and related study.

Link Prediction and Route Selection Based on Channel State Detection in UASNs

In Underwater Acoustic Sensor Networks (UASNs), data route is often disrupted by link interruption which will further lead to incorrect data transmission due to high propagation delay, Doppler effect, and the vulnerability of water environment in acoustic channel. So how to correctly transmit data when there are interrupted links on the data path is just the issue Delay Tolerant Networks (DTNs) aim to solve. In this paper, we propose a model to predict link interruption and route interruption in UASNs by the historical link information and channel state obtained by periodic detection. A method of decomposing and recomposing routes hop by hop in order to optimize route reselection is also presented. Moreover, we present a back-up route maintenance scheme to keep back-up routes with fresh information. In case of single route, we advance the idea to utilize the periodicity of environmental changes to help predict link interruption. In the simulation, we make comparisons on node energy consumption, end-to-end delay as well as bit error rate with and without link prediction. It can be derived that the network performance is significantly improved with our mechanism, so that our mechanism is effective and efficient while guaranteeing reliable data transmission.

Research on Wireless Sensor Network and Carrying Network Integration Based on Gateway

In this paper, we analyze the protocol architecture of Wireless Sensor Networks (WSNs) and carrying networks, and propose a connection scheme based on gateway, which is suitable to the integration of these two networks. According to the characteristics of these gateways, we put forward the concept of end-to-end connection, give the address mapping scheme to the gateway and design a simple gateway node. To realize higher connection reliability, we advance a method of backup gateway and multi-gateways selections. This work can greatly facilitate the research for connecting WSN with the carrying network, IoT (Internet of Things), which also makes contribution to the influence of this connection.

A Network Access Mechanism for Multihop Underwater Acoustic Local Area Networks

Multihop underwater acoustic local area networks (MUA-LANs), which can greatly improve the access ability of underwater networks, suffer from the lack of network access mechanism utilized by new nodes to join the networks. Existing network access mechanisms for terrestrial wireless LANs cannot be directly applied to MUA-LANs due to the multihop topologies of MUA-LANs and the acoustic channel features of limited bandwidth and high propagation delay. In this paper, we present a network access mechanism constituted by three phases of network discovery, relay path determining, and association for MUA-LANs. The basic idea of our network access mechanism is to let the nodes that have joined a network assist new nodes in accessing the network by multihop relay forwarding. We theoretically verify that the unbalanced energy consumption is serious in MUA-LANs. Therefore, we present a lifetime and energy efficiency-based relay path selection algorithm in relay path determining phase. This algorithm can significantly prolong the network lifetime and improve energy efficiency. In association phase, we employ a MAC address forwarding tables mechanism. By utilizing this mechanism, multihop relay forwarding can be realized easily. The simulation results have confirmed that the proposed network access mechanism can achieve excellent performance owing to the lifetime and energy efficiency-based relay path selection algorithm and the MAC address forwarding tables mechanism.

Carrying Network Accessing Architecture and Strategy Based on Business Differentiation

Due to the abilities of real-time sensing and information sharing, Wireless Sensor Network (WSN) has been applied in more and more fields. Basing on the emergence of Internet of Things (IoT), the issue about heterogeneous network integration is becoming more important. We first analyze the new businesses that arise recently for cell phone users as well as the potential effect on carrying network. After that we mainly discuss the influence on traditional carrying network for WSN accessing and taking concurrent businesses as the study case, common access architecture from WSN to carrying network is constructed, which makes use of business differentiation. Furthermore, we propose the idea of tortuous access from WSN to the gateway in the carrying network to avoid congested paths with simulation and verification. Finally, we conclude the possible impacts for the integration of these two networks and present possible solutions.