Spectrum Sensing RF Front-End Module for Cognitive Radio Applications

Broadband high speed wireless data links have continuously increased the demand
for bandwidth in the wireless spectrum such that it has become a very
scarce resource. Therefore, there is a strong need for highly efficient concepts
of its use.
Cognitive radio is one such concept. By accessing temporally and spatially
under-utilized frequency bands, an interference free re-use of the spectrum
shall be ensured. Due to the wideband nature of the spectrum in question, the
realization of the concept raises technical challenges for the design of hardware
and software algorithms.
In this thesis, a spectrum sensing module for cognitive radio applications is
proposed. It is based upon an up/down-heterodyne receiver architecture and
consists of several Si/SiGe:C BiCMOS radio frequency integrated circuits. This
architecture is very well suited for wideband high dynamic range scenarios.
Its requirements are derived through an extensive measurement campaign.
Finally, a first spectrum sensing demonstrator was realized, incorporating the
spectrum sensing module and an evaluation-board containing analog-to-digital
converters (ADCs) and a field-programmable gate array (FPGA). By sensing
several primary users in a real RF environment, its functionality is successful
demonstrated.