Network controlled adaptive antenna tilting in multi-band UMTS FDD

This work proposes an adaptive antenna tilting approach in an overlay UMTS FDD network. The purpose is to introduce and investigate an antenna element, which can be remotely controlled by the radio network, in order to adequately cater for the spatial and temporal dynamic traffic distributions. The tilting angle is computed by a two level control mechanism: the higher level is controlled by the network manager and consists of a look-up table with the possible ranges (intervals or discrete steps for angles) of the antenna angle adjustments. The element manager, e.g. RNC controlling and recording the track of the dynamic antenna changes, controls the lower level. To enhance the system reliability, we associate the less dynamic traffic with the primary fixed tilt antenna, whereas the more varying traffic is controlled by a second more dynamically tilted antenna element. Through system level simulations, we show that significant gains in term of system capacity can be obtained. In addition, solutions involving the network management subsystem in UMTS FDD are also given, where the element management platform interacts with the performance measurement units. Intelligent inter-frequency handovers are deliberately discussed.