An Attenuation Model of Node Signals in Wireless Underground Sensor Networks

Wireless underground sensor networks (WUSN) consist of sensor nodes that are operated in the soil medium. To evaluate the signal attenuation law of WUSN nodes, in this study, a WUSN node signal transmission test platform was built in the laboratory. The signal intensity data of WUSN nodes under different experimental conditions were obtained by orthogonal test. The WUSN node signal attenuation model was established. The test results show that the transmission of WUSN node signals in the soil medium is seriously affected by soil moisture content, node burial depth, soil compactness, and horizontal distance between nodes. The R2 of the models was between 0.790 and 0.893, and the RMSE of the models was between 2.489 and 4.192 dbm. Then, the WUSN node signal attenuation model involving the four factors was established. The R2 and RMSE of the model were, respectively, 0.822 and 4.87 dbm. The WUSN node signal attenuation model established in this paper can facilitate WUSN node deployment.

Climatic Bases and Analysis of Proposed Cloud Attenuation Model for Satellite Links Application

Consistently required lager bandwidth at lower cost induce increases in magnitude of transmission frequency for satellite signal. This is phenomenally accompanied by proportional hydrometeors attenuation. Hence, there is need to evaluate cloud attenuation impact in every climatic region periodically. This report is one of the outcomes of experimental communication research carried out at tropical Ota (6.7oN, 3.23oE) station, southwest, Nigeria. The station spectrum analyzer measures its received beacons total attenuation at 12.245 GHz and elevation angle 59.9o to Astra satellites located at 28.2oE. Daily maximum, minimum and mean temperatures; rain amount, wind speed and direction as well as time of occurrence of each of these weather parameters were also measured. Then the radiometric data including acquired radiosonde data were analysed under rainy and non-rainy conditions, to obtain cloud attenuation contribution from the total attenuation measured per minute. The various data used range in measurement periods between four and fifty-eight years. The outputs were used to compute the station cumulative distributions for the existing cloud models and for the integrated station’s data. Statistical analysis comparing the two cumulative distributions show a high difference between the measured data and existing models’ predicted values. Hence a cloud attenuation computation algorithm and its simulation program were developed and used to derive a new tropical cloud attenuation model. The results of climatic data and analysis were used to justify the well corroborated new cloud attenuation model.

An overview of rain attenuation research in Bangladesh

The demands of shifting to the operating frequency of wireless telecommunication systems at new higher frequency bands increase as day by day the necessity to transfer more data volume through wireless networks. Bangladesh has launched its first satel-lite, Bangabandhu-1, with 40 communication channels in the C and Ku frequency bands. Besides, a huge volume of terrestrial microwave backbone networks suffer from fading during rain across the country. Bangladesh experiences heavy rainfall in June-July-August. The rain has a remarkable impact on deteriorating the signal-to-noise ratio at the receiver end. To implement the 5G network, 2.6–60 GHz frequency bands are promising. However, the propagated waves in these bands are prone to fadedue to rain. Unfortunately, the rain attenuation model developed for other climatic conditions can not be used readily without customization. In this regard, to maintain quality telecommunication networks, proper rain attenuation model development is crucial. This work reviews rain attenuation research in Bangladesh, global research trends and the research scope to manage rain attenuation.