Positioning mechanisms were specified in 3GPP as a key feature for E-UTRA networks since Release 9, e.g. OTDOA,
E-CID etc. They are not only used in helping meet regulatory requirements, but also utilized with increasing importance
to enable all kinds of location based applications.
The proliferation of heterogeneous network deployments brings some challenges also in the area of efficient terminal
positioning and calls for the study of enhanced mechanisms and positioning performance requirements.
The addition of multiple nodes in heterogeneous networks can improve the position accuracy remarkably if the
specificities of such deployments are taken into account in the positioning mechanisms. Some examples include the
support of several transmission points with identical cell IDs and improved support for positioning in carrier
Furthermore, the accuracy of current positioning mechanisms and in particular OTDOA and E-CID based on UE Rx-Tx
time difference measurement is only defined for limited scenarios:
Limited channel bandwidth for the cells to be measured (reference and neighbour cells)
Tests defined assuming single Tx antenna. Practical network might have Tx diversity on antenna port 6 which is
used for RSTD measurements
It is desirable to study the possibility of enhanced accuracy for other practical deployment scenarios.