A Novel Channel Estimation Sequence for Multi-Antenna UWB Systems

Disclosed is a multiple layered film preferably in the form of a tube and being suitable for forming sausage casings, comprising: a central layer of a cellulose hydrate-based material; a first layer on the inside of the central layer, comprising a film of thermoplastic synthetic resinous material and being impermeable to water and water vapor; and a second layer on the outside of the central layer, comprising a synthetic elastic copolymer and being permeable to water and water vapor. Also disclosed is a method for preparing these film products.