  The objective of this paper is to extend the idea of Cognitive Relay (CR).
CR, as a secondary user, follows an underlay paradigm to endorse secondary
usage of the spectrum to the indoor devices. To seek a spatial opportunity,
i.e., deciding its transmission over the primary user channels, CR models its
deployment scenario and the movements of the primary receivers and indoor
devices. Modeling is beneficial for theoretical analysis, however it is also
important to ensure the performance of CR in a real scenario. We consider
briefly, the challenges involved while deploying a hardware prototype of such a
system.
