Load balancing effect of inter-frequency handover with pilot power tuning in UTRAN

Load balancing is an important technique in radio resource management (RRM). In future, when several frequencies are required to cover an increasing number of users and an increasing amount of traffic, inter-frequency handover (IFHO) will perform an important role in load balancing between frequencies. Meanwhile, there is usually a geographic load imbalance in real networks and changing coverage by tuning the common pilot channel (CPICH) power can mitigate this geographic load imbalance. Using a dynamic WCDMA simulator, we evaluate RRM techniques combining IFHO and CPICH power tuning for load balancing and for achieving better performance. First, we compare the IFHO performances in terms of the IFHO trigger types. We show that the CPICH E_c/N_o (code energy divided by noise energy)-triggered IFHO can achieve 30-40 % downlink (DL) load decreases in a hotspot area. Next, we analyze the relation between the IFHO and CPICH power tuning, by comparing the effect of CPICH power tuning with and without the IFHO function and show its performance by using the simulator. Then, finally, we propose an example procedure to utilize the combination of IFHO and CPICH power tuning based on the revealed relation between them.