From smart antennas to reduced dimension space-time processing

The Integrated Broadband Mobile System (IBMS) is a concept for future wireless communications systems that has been developed in order to integrate heterogeneous services and applications into a common framework. Smart antennas are used as the enabling technology to support high and variable data rates. A hardware testbed was developed for the investigation of algorithms and real-time aspects of smart antennas, which uses separate stages for processing of spatial and temporal information. Research results indicate that the system performance can be enhanced using a space-time processor (STP) which carries out spatial and temporal information processing jointly. This paper reviews the IBMS physical layer and presents the results obtained with the smart antenna demonstrator. A new STP concept with reduced signal dimension by means of the Karhunen-Loeve-Transformation (KLT) is introduced and analyzed.