Mobility Performance in Heterogeneous LTE Networks with Indoor Base Stations

In this paper mobility performance is studied in heterogeneous networks with both macro and indoor base stations. Due to abrupt changes in received signal and interference level as User Equipment (UE) enters and leaves a building with indoor Home eNodeB (HeNB) there may be additional challenges for handover compared to more homogeneous network layout. The purpose of this paper is, with dynamic system simulation tool, to evaluate the magnitude of the handover challenges and how would the system need to be configured to optimize the mobility performance. The results indicate that while general handover parameterization can be effectively utilized to avoid the most of mobility problems, cell-specific parameterization can further improve the mobility performance between eNB and HeNB. Additionally, attention should be paid to both inbound and outbound HeNB mobility due to possibly very different interference conditions in handover situations inside the building with HeNB and outdoor environment.