Evaluation of Mobility Performance and Deployment Scenarios in UMTS Heterogeneous Networks

While a heterogeneous network increases the system performance in terms of coverage and capacity, if it is deployed without being well planned and without making use of optimized configurations, it could potentially lead to tough requirements on the mobility performance. The system level simulations shows that in typical scenarios the small separated cell deployment (each low power node is deployed as a separate cell) meets mobility requirements from the regular network operations perspective. However, in challenging mobility scenarios, small separated cell deployment might suffer from the degradation in mobility performance due to the non-optimal handover settings. The proposed combined cell deployment (low power nodes and macro cell use the same cell identity) provides an effective alternative to improve mobility in terms of reduced handover numbers and improved transmission robustness for handover signaling, therefore simplifying the network planning and management.