The present document is a technical report for LTE Advanced 2ULs and xDLs Carrier Aggregation with x=3,4,5 under Rel-15 time frame. The purpose is to gather the relevant background information and studies in order to address 2ULs and xDLs Carrier Aggregation requirements. This TR covers relevant background information and studies core & performance requirements for the Rel-15 band combinations in Table 1-1, 1-2 and 1-3.       This TR contains a general part and band specific combination part. The actual requirements are added to the corresponding technical specifications.