Inter-Frequency Re-Selection for CSG Cell Interference Avoidance in LTE Network

In 3GPP Rel'8 access to a Home eNodeB may be restricted to only UEs belonging to a Closed Subscriber Group (CSG). These cells are called CSG cells and a UE with CSG subscription would have an Allowed CSG List containing CSG Identities associated with the CSG cells on which the UE is allowed access. This however, can be problematic for the users located near the CSG cells, but who are not allowed to access them. The interference caused by the CSG cell can be devastating if the UE is connected to a macro cell using the same frequency. Some solutions for these interference problems have been proposed in 3GPP standardization and in this study we have evaluated the performance of different options for handling the interference issues related to mixed carrier CSG deployments. The proposals utilize different details of the LTE re-selection algorithm and suggestion on the best solution is also given.