Abstract: A simple signals spreading model in urban microcellcommunication enviroments is presented.The model is based on geometrical opticsand uniform theory of diffraction.Raytracing technologies is used in the model,both reflection and diffraction rays is considered.The field strength of reflection and diffraction rays is calculated in the local ray-fixed coordinate systemsto obtain the total field and pathloss of signals site.The calculated results ofthe signal path loss along the streets are compared with the published experimental results, showing that the model can predict signal strenths in these environments with good agreement.

Key words: pathloss, ray tracing, propagation model