Layout Optimization for Greenhouse WSN Based on Path Loss Analysis

When wireless sensor networks (WSN) are deployed in the vegetablegreenhouse with dynamic connectivity and interference environment, it is necessary to increase the node transmit power to ensure the communication quality,which leads to serious network interference. To offset the negative impact, thetransmit power of other nodes must also be increased. The result is that the network becomes worse and worse, and node energy is wasted a lot. Taking intoaccount the irregular connection range in the cucumber greenhouse WSN, wemeasured the transmission characteristics of wireless signals under the 2.4 Ghzoperating frequency. For improving network layout in the greenhouse, a semiempirical prediction model of signal loss is then studied based on the measureddata. Compared with other models, the average relative error of this semi-empiricalsignal loss model is only 2.3%. Finally, by combining the improved networktopology algorithm and tabu search, this paper studies a greenhouse WSN layoutthat can reduce path loss, save energy, and ensure communication quality. Giventhe limitation of node-degree constraint in traditional network layout algorithms,the improved algorithm applies the forwarding constraint to balance network energyconsumption and constructs asymmetric network communication links. Experimentalresults show that this research can realize the energy consumption optimization ofWSN layout in the greenhouse.