Major research activity
As mobile communication devices like smart phone become more widely used, mobile communication environments with high data transfer speeds are needed more and more. However, the mobile communication environment has a complicated structure for radio wave propagation, and the radio channel has space- and time-variant characteristics as a mobile phone user moves or the surrounding objects move. To realize high efficiency data transmission rates in such environments, it is required to overcome those space-time variant characteristics in the radio propagation environment. Therefore, it is fundamentally significant to clarify the details of channel characteristics, and to produce their accurate channel models.
In Taga laboratory, the theoretical and experimental research for various kinds of mobile channel characteristics and their modeling are energetically continued. As the recent results, a time-varying path-shadowing model for indoor mobile communications and a statistical scattering model in macro-cellar mobile environments have been developed. A theoretical and experimental evaluation of the mean effective gain of mobile antennas in micro-cellar mobile environments has been presented. The path shadowing model is now expanding to apply with a path modeling in the inter-vehicle communication in ITS. Furthermore, the performance evaluation of MIMO systems, and theoretical formulation for radio propagation mechanisms are now under investigation.
Major relevant publications
- I. Kashiwagi, T. Taga, and T. Imai : Time-Varying Path-Shadowing Model for Indoor Populated Environments, IEEE Trans. on Vehicular Technology, Vol.VT-59, No.1, pp.16-28 (Jan. 2010).
- A. Ando, T. Taga, A. Kondo, K. Kagoshima, and S. Kubota : Mean Effective Gain of Mobile Antennas in Line-of-Sight Microcells With Low Base Station Antennas, IEEE Trans. on Antennas and Propagation, Vol. AP-56, No.11, pp.3552-3565 (Nov. 2008).
- T. Imai and T. Taga : Statistical Scattering Model in Urban Propagation Environment, IEEE Trans. on Veh. Technol., Vol. VT-55, No.4, pp.1081-1093 (July 2006).