Interpolation distortion in Large-Scale Parameter maps for wireless system simulation

Spatial Channel Models (SCM) used in wireless system simulations are determined by Large-Scale Parameters (LSP). LSPs include delay spread, shadow fading, angle of arrival and departure spread, and Rice K for line-of-sight channels. LSPs are modeled as a spatially correlated random field over the geometry of the network scenario being simulated. The general method is to generate an LSP map on a discrete lattice (or grid) and induce spatial correlation via spatial filtering as determined by the LSP's correlation distance. This step represents a large part of the simulator's computation load, which leads to the use of a coarsely spaced lattice and interpolation from nearest lattice points to arbitrary UE locations on the x-y plane. We investigate the computation vs. fidelity trade associated with LSP generation. We will show that when a coarse grid is employed, there can be significant nonstationary distortion of the LSP correlation due to the interpolation step. We investigate three different interpolators having varying correlation fidelity and computation load.