Study of Radio Base Station Receiver Topologies for Multiband use

Abstract

This thesis proposes a dual band receiver as a multiband solution for a Wide Area Radiobase station type 3GPP compliant. The solution consists of two independent superheterodyne branches operating with Band 1 Uplink (1920-1980 MHz) and Band 3 Uplink (1710-1785 MHz), 5 MHz channel bandwidth per band, and FDD mode. The design and implementation comprehend from the input of the RF Cavity filter to the input of the ADC. The work performed has different stages: design, implementation, and laboratory tests. In the design part, a frequency plan was performed; it consists in the selection of the intermediate frequency and spurs analysis. Afterwards, the calculation of the selectivity in order to fulfill some 3GPP specifications, image, Nyquist aliasing, and spur rejection were performed. In the implementation stage, the components were selected, the link budget was calculated and the prototype of the dual band receiver was built in a test board level. Finally, in the laboratory the Noise Figure, Gain, IIP3 of each branch were measured. 3GPP co-location specification was measured too, for each branch, and inter branch. The results obtained in the laboratory, Noise Figure and IIP3 are 3GPP compliant. Good margins exist in all cases, 1 and more than 10 dB respectively. The co-location specification is 3GPP compliant. In terms of the receiver architecture, the superheterodyne gives a feasible but not trivial solution, the more bands you add, the more complicated the frequency planning becomes. Further studies are recommended to really say if the receiver is fully 3GPP compliant. This work is just a small part of the big chain in the receiver design.