Path models and mimo capacity for measured indoor channels at 5.8 GHz

Cumulative distribution functions (CDFs) for multiple-input-multiple-output (MIMO) capacities are computed for flat-fading indoor channels at 5.8 GHz. These CDFs are based on two measured channels and on reconstructions of the MIMO channels from path parameters that are estimated based on measured data. The measured data was obtained using the stepped-frequency method of channel sounding in combination with 3-D virtual arrays (also known as synthetic arrays) at both ends of the link. The channels were measured for various antenna element spacings. Several versions of the ESPRIT approach are used to estimate the complex amplitudes, delays, directions-of-arrival (DOAs) and directions-of-departure (DODs) of each path of propagation. One version sequentially estimates each set of parameters. Another version estimates the delays and then jointly estimates the DOAs and DODs, and still other versions jointly estimate all the parameters. A residual estimation error (REE) approach to detecting the number of paths is proposed. We compare the REE results and the capacity CDFs for the different parameter estimation methods and for different antenna element spacings. Sensitivity of the capacity to spacing is observed.