Research of Multidimensional Optimization of LEACH Protocol Based on Reducing Network Energy Consumption

In order to equalize network energy consumption, and extend the life cycle, the optimized protocol based on low-power adaptive cluster stratification (LEACH) is proposed. Firstly, considering residual energy and distance of nodes, the threshold function of the cluster head is modified, and the network region division strategy is optimized, to reasonably adjust the size of clusters. For intracluster transmission, a sleep mechanism is added to balance node energy consumption. And a new barycenter node is added to assist cluster head (CH) to complete the transmission task, thereby extending the service lifetime. In the multihop communication between clusters, in order to calculate the fitting factor of the next hop, we derived a new formula, which takes into account the angle, remaining energy, and distance. Simulation results show that the total remaining energy of the optimized LEACH protocol is reduced by 31.4%, and the network life cycle is increased by about 52%.

Mitigating Hotspot Issue in WSN Using Sensor Nodes with Varying Initial Energy Levels and Quantification Algorithm

A typical Wireless Sensor Network (WSN) uses multihop communication rather than direct transmission. In a multi-hop communication, the sensor node communicates the sensed data to its neighbor node, which is comparatively closer to the sink and the receiving node will forward the data to its neighbor node. This process continues until the data reaches the sink. Due to the multihop communication, the nodes closer to the sink have to transmit and receive more data and control packets compared to other nodes. Hence, the nodes closer to sink may deplete their energy at a faster rate and may die soon. This may create network isolation. This issue is called as the Hotspot problem. In this paper, we are proposing a Quantification algorithm for Sensor Nodes with varying Initial Energy Level to mitigate the Hotspot effect.

Bringing Geospatial Data Closer to Mobile Users: A Caching Approach Based on Vector Tiles for Wireless Multihop Scenarios

Mobile applications based on geospatial data are nowadays extensively used to support people’s daily activities. Despite the potential overlap among nearby users’ geospatial data demands, it has not been feasible to share geospatial data with peer wireless devices directly. To address this issue, we designed a scheme based on vector tiles to organize spatial data and proposed a system named GeoTile for geospatial data caching and sharing. In GeoTile, a tile request from the mobile client relies on multihop communication over intermediate nodes to reach the server. Since GeoTile enables all network nodes to cache and process geospatial data tiles, requests may be handled before they actually reach the server. We implement the GeoTile prototype system and conduct comprehensive real-world experiments to evaluate the performance. The result shows that the GeoTile system can serve vector tiles for users conveniently and friendly. In addition, the caching mechanism based on vector tiles can substantially reduce the response time and network throughput under the wireless multihop scenarios.

Designing a Channel Access Mechanism for Wireless Sensor Network

Although there are various Medium Access Control (MAC) protocols proposed for Wireless Sensor Network (WSN), there is no protocol accepted as a standard specific to it. This paper deals with completing the design of our previously proposed MAC for WSN by proposing a channel access mechanism (CAM). The CAM is based on developing a backoff mechanism which mainly differentiates nodes’ backoffs depending on their different identification numbers, and it employs a performance tuning parameter for reaching a required performance objective. The probability distribution of the backoff period is constructed and Markov chain modeling is used to analyze and evaluate the CAM against the IEEE802.15.4 slotted CSMA/CA based on single- and multihop communication with respect to the reliability, the average delay, the power consumption, and the throughput. The analysis reveals that the required performance of CAM against the IEEE slotted CSMA/CA can be obtained by choosing the maximum backoff stages number and the tuning parameter value and that CAM performs better than the IEEE with larger nodes number. The multihop scenario results in a good end-to-end performance of CAM with respect to the reliability and delay becomes better with lengthier paths at the expense of increasing the energy consumption.