A Unified Hollow-Disk Scattering Model: Angle-of-Departure and Time-of-Arrival Statistics
In order to ensure the required wireless communication system performances, it is necessary to have an efficient communication channel model, which is capable of considering all channel degradation factors fairly. In this paper, a unified hollow-disk geometrically based stochastic channel model is derived. This model assumes that the scatterers are distributed in a hollow-disk area around a mobile station. Namely, the scatterer distribution is derived as a projection of $\boldsymbol{d}$-dimensional uniformly distributed scatterers into two-dimensional space. According to this generalization, derived model is capable of obtaining uniform circular, uniform ring, uniform hollow-disk, and unified disk scattering model as special cases, as well as modeling a whole new group of hollow-disk models. Under an assumption of single bounce scattering and omnidirectional antennas at transmitter and receiver, joint probability density function (PDF) of angle-of-departure and angle-of-arrival, as well as the joint PDF of time-of-arrival and angle-of-arrival are derived. Subsequently, the corresponding marginal PDFs are provided in a closed form. Thus, derived PDFs are suitable for any position of the base station, (base station placed inside or outside of scattering region). The proposed model is validated by several measured channels. The curve fitting results shown the high flexibility of the proposed model and outperforming results compared with several other geometric scattering models.