Evaluation of link-level performance improvements by using smart antennas for the TD-CDMA based UTRA TDD mobile radio system

For third generation mobile radio systems like the TD-CDMA based UTRA TDD mode the use of smart antenna technology promises a substantial performance improvement on the up- and the downlink. The third generation mobile radio system UTRA with the TDD mode, which utilizes a combined CDMA and TDMA multiple access scheme, has been specified in the Third Generation Partnership Project (3GPP). The use of smart antennas at the base station reduces interference in two ways: on the uplink the intercell interference can be suppressed. The estimated spatial information about the users and interferers can then be used for beamforming on the downlink, which significantly reduces the interference also in this direction. Especially for terminals with a RAKE-receiver-structure a major performance improvement can be observed because of the intracell interference reduction. These performance improvements are expressed in concrete results derived from link-level simulations using the described technology and simulation environment.