Subspace Transmission for Frequency-Division Duplex Mobile Wireless Systems
نویسندگان
چکیده
A novel approach to the adaptive transmission to combat fast fading effect in mobile wireless systems is presented. In this approach, the downlink beamforming weights of the base station antennas are generated based on the orthogonal basis of the uplink signal subspace. The signal intended for a particular mobile user is transmitted through its corresponding signal subspace. Due to the stability of the signal subspace, the received signal at the mobile is immune to fast fading. This adaptive transmission approach is open-loop and applicable to practical FDD systems, thanks to the negligible distance between the uplink and downlink signal subspaces. Ray tracing simulations in a 3D urban physical model show that the subspace transmission scheme enhances the link quality of wireless systems over fast fading channels.
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