Simple upper bound on MIMO capacity mean with separable parameterizations of Rician fading

Summary form only given. This paper deals with the problem of MIMO link capacity assessment. A directional MIMO channel in the presence of Rician fading and physical scattering is considered herein instead of most previous analysis model whose transfer function H is preassigned as a circularly symmetric complex-valued Gaussian random matrix. Spatial parameter of the model is firstly separated into directional mean and its associating standard deviation, called, nominal direction and angular spread, respectively. An upper bound on ergodic mean capacity is then proposed by using such a separable parameterization. The proposed upper bound provides, fortunately, deep insight into Rician-fading and physical scattering because it can be shown as a deterministic function of Rice factor, nominal direction, and angular spread. Since it does not require any eigenvalue decomposition, the bound computation is thus very simple. Numerical examples are conducted to support not only the bound tightness compared with sample mean capacity, but also relationships of the bound to indicated parameters.