This TR provides background information, motivations, concepts and requirements regarding an extended Network Assisted Cell Change (NACC) feature for external cell change support. Cell change between GERAN and
UTRAN cells is outside the scope of this report, although consideration has been taken in order to allow an easier
extensibility to that case. The extension is based on the Release 4 version of the NACC feature where the mobile station
is only supported by the NACC when performing internal cell re-selection, i.e. within a BSC. The extension of the
feature is for GERAN just affecting BSS and for the core network the SGSN and signalling links between these network
nodes. To support cell changes between GERAN and UTRAN, also the Um and the Uu interfaces are affected.
full Table of Contents for TR 44.901 Word version: 15.0.0