A quadruplexer outdoor branching unit for carrier aggregation radio communications systems

A physical channel branching unit for broadband communications is introduced. Such design facilitates carrier aggregation, a concept considered as the enabler for LTE technology (LTE is the last step toward the 4th generation of radio technologies designed to increase the capacity and speed of mobile telephone networks), to be promoted in the microwave frequency domain. What forms the proposed single outdoor unit is a four-channel circulator/filter chain, two for receiving and two for transmitting respectively. Such unit of certain frequency selectivity is ease of branching with another one of different frequency responses. Doing so yields radio-link bounding for higher bit-rate capacity while reusing single antenna system, meanwhile lowering demand for extra room in base station. In this paper, specification is defined and design method and implementation are addressed. Promising results for the initial prototype are demonstrated by simulation and measurement data. Lessons learnt and certain aspects for further phase of industrialized development are discussed as well.