Frequency‐Domain Inter‐cell Interference Coordination

This chapter explores the possibility of avoiding inter‐tier interference by using frequency‐domain multiplexing. The description of the technical nature of the so‐called carrier aggregation (CAG) framework in long‐term evolution (LTE) and its applications to frequency‐domain interference coordination in heterogeneous networks are the main topic of the chapter. The concept of CAG has been first introduced for the high‐speed packet access (HSPA) standards for wireless networking under the name of dual‐carrier high‐speed packet access (DC‐HSPA). The chapter offers a more detailed view on the CAG protocol architecture, standardized signaling, and implementation aspects. The CAG framework started in LTE Release 10 with a basic support of CAG features, generally enabling aggregation of up to five carriers of the same frame structure. LTE Release 11 extended the supported CAG combinations and defined CAG with multiple uplink timing advances as well as inter‐band TDD CAG with different uplink‐downlink configurations.