Traffic Offloading In LTE-Advanced Based On Active Antenna

Active antenna is introduced into LTE-Advanced system in order to enhance available system capacity which is based on limited spectrum resources.Advanced structures of active antenna system provide various network scenarios.There are still traffic hot spots in these new scenarios,for user's movement and unbalanced traffic density.Traditional traffic offloading algorithms do not apply to these new scenarios.Active antenna system can realize cell splitting at cell level or user equipment beam forming at user level.This paper will study on active antenna scenarios'traffic offloading from these two aspects.This paper builds a system level simulation platform based on 3GPP simulation standard,and carry out simulation on system throughput in single beam network and multi-beam network.This platform is also used as simulation tool in the following content.For the aspect of cell splitting,this paper studies emphatically on offloading between beams.Cell splitting of active antenna reduces space isolation between beams and increases frequency interference.The paper uses this feature to establish an offloading model and a set of principle.Based on the above content,this paper presents a single step offloading algorithm for single hotspot beam problem.The simulation results reveal the effectiveness of the proposed algorithm.Further,for regional hotspot beams,the paper models the offloading network as a graph,and simplifies the scenario into a single-to-single vertex model.Based on single step offloading algorithm,the paper presents a multi-step offloading algorithm.The simulation results reveal that the proposed algorithm can effectively solve regional hotspot issue.For the aspect of user beam forming,the paper studies emphatically offloading hotspot site selection in the heterogeneous network of user beam forming and small cell.Active antenna provides user data of spatial angle.And the user spatial angle data can provide statistical analysis of user's spatial location.This paper presents an offloading hotspot site selection algorithm,BR-K-Clusters algorithm based on statistical learning clustering method.And the effectiveness of proposed algorithm is demonstrated by the simulation results.