Wideband Characterization of Backscatter Channels: Derivations and Theoretical Background

The wireless channel of backscatter radio systems is a two-way pinhole channel, created by the concatenation of two standard wireless channels. We present a method to calculate wideband channel parameters of backscatter channels based on the parameters of the constituent one-way channels. The focus is on characteristics that are vital for narrowband and wideband ranging, such as the K-factor w.r.t. the direct (line-of-sight) path and the RMS delay spread. The presented analyses include uncorrelated as well as correlated channel pairs and are thus valid for bistatic and monostatic antenna setups. We also show that the uncorrelated scattering (US) assumption holds for the backscatter channel provided that the constituent channels are US.