K.1 Deployment scenarios

36.3003GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN)Overall descriptionRelease 17Stage 2TS

Two scenarios have been identified where conventional ICIC techniques are insufficient to overcome co-channel interference, the CSG scenario and the Pico scenario. The identified scenarios are examples of network configurations that are intended to depict the basic concept of time domain ICIC and it should be understood that other network deployment scenarios are also possible.

K.1.1 CSG scenario

Dominant interference condition may happen when non-member users are in close proximity of a CSG cell. Depending on network deployment and strategy, it may not be possible to divert the users suffering from inter-cell interference to another E-UTRA carrier or other RAT. Time domain ICIC may be used to allow such non-member UEs to remain served by the macro cell on the same frequency layer.

Such interference may be mitigated by the CSG cell utilizing Almost Blank Subframes to protect the corresponding macro cell’s subframes from the interference. A non-member UE may be signalled to utilize the protected resources for cell measurements (RRM), radio link monitoring (RLM) and CSI measurements for the serving macro cell, allowing the UE to continue to be served by the macro cell under strong interference from the CSG cell.

Figure K.1.1-1: Time domain ICIC: CSG scenario

In RRC_CONNECTED, the network can find out that the UE is subject to dominant interference from a CSG cell which the UE is not a member of through the existing measurement events (defined in release-8/9), at which point the network may choose to configure the RRM/RLM/CSI measurement resource restriction for the UE. The network may also configure RRM measurement resource restriction for neighbour cells in order to facilitate mobility from the serving macro cell. The network may release the RRM/RLM/CSI measurement resource restriction when it detects that the UE is no longer severely interfered by the CSG cell.

K.1.2 Pico scenario

Time domain ICIC may be utilized for pico users who served in the edge of the serving pico cell, e.g. for traffic off-loading from a macro cell to a pico cell. Time domain ICIC may be utilized to allow such UEs to remain served by the pico cell on the same frequency layer.

Such interference may be mitigated by the macro cell(s) utilizing Almost Blank Subframes to protect the corresponding pico cell’s subframes from the interference. A UE served by a pico cell uses the protected resources for cell measurements (RRM), radio link monitoring (RLM) and CSI measurements for the serving pico cell.

Figure K.1.2-1: Time domain ICIC: Pico scenario

For a UE served by a pico cell, the RRM/RLM/CSI measurement resource restriction may allow more accurate measurement of pico cell under strong interference from the macro cell(s). The pico cell may selectively configure the RRM/RLM/CSI measurement resource restriction only for those UEs subject to strong interference from the macro cell(s). Also, for a UE served by a macro cell, the network may configure RRM measurement resource restriction for neighbour cells in order to facilitate mobility from the macro cell to a pico cell.

Annex L (informative):
Void

Annex M (informative):
Dual Connectivity