Component Carrier Selection In Lte-Advanced System With Carrier Aggregation

With the rapid development of mobile communication technology and the diversity of mobile service, the spectrum resource becomes more and more precious. How to realize larger system capacity and higher spectrum utility with the limited spectrum becomes the key technology of next generation mobile communication technology in the future.3GPP proposed the concept of Carrier Aggregation (CA) to support wider transmission bandwidth and full use of discrete carriers. When the system implements the CA procedure, the eNB needs to select some appropriate component carrier (CC)s according to the channel quality or traffic road of system to avoid the case that some UE operate with bad quality CCs for a long time. Therefore, CC selection not only reduces scheduling road and improves the system throughput, but also offers an efficient way to improve the utility of CA in LTE-Advanced system.In this paper, the CC selection method is studied in the macrocell downlink system. The current RSRP measurement based CC selection strategy can select high quality CCs for the coming UE, but cannot guarantee the load balance in the system which may lead to the decline of system performance. And the load balance based CC selection method is able to achieve system load balance very well, but inefficient in achieving high system capacity due to the lack of consideration for channel quality. And all of these existing schemes do not take the characteristics of diverse CA scenarios into account, since every scheme may have different effect on different scenarios. To solve the problem in the existing schemes, two modified CC selection schemes are designed with the different characteristics of CA deployment scenario in this paper. One of the CA deployment scenarios is identical coverage scenario, in which all eNBs are colocated and have the same beam directions. In this scenario, a Graph Coloring based CC Selection (GC-CS) scheme is proposed to reduce the intercell interference and improve the whole system throughput. And the other scenario is diverse coverage, in which all CCs are dispersed in different spectrum bands and have different coverage. In such a scenario, a Utility Balance based CC Selection (UB-CS) scheme is proposed to ensure the system load balance, reduce aggregation complexity and achieve higher system performance gain. And finally, two proposed CC selection methods are simulated with the Matlab.