Localized behaviors of rain measured in Tokyo Tech millimeter-wave wireless network

Evaluation of localized and time-varying behaviors of rain in Tokyo Tech millimeter-wave wireless network is presented in this paper. Data about Rain rate, Bit Error Rate (BER) and Rx level are being collected since March 2008. Based on the data, we performed conventional statistical analysis such as measuring rain attenuation constant, cumulative rain rate distribution, relation between availability and path distance. These measurements will be used for link design and also for enhancing the link reliability. Based upon the study up to now, the unique effects due to highly localized/microscopic behaviors of the strong rain have become clear. The cell size of the strong rain frequently becomes smaller than 1km, the size of the campus. Comparison between rain attenuation of 25GHz and 38 GHz band network has been investigated. The high sensitivity of the receiving level against the rain can be utilized to inversely estimate the rain rate using measured rain attenuation. The novel application of millimeter wave as the rain sensing networks is proposed.