Using reconfigurable devices to maximize spectral efficiency in future heterogeneous wireless systems

As broadband data further blends with cellular voice, mobile devices will become the dominant portals to the connected world. However current design practices still involve building independent networks that each make their own resource decisions. In spite of the tremendous amount of related research in this area, there are still several elemental questions that must be addressed. First, is it better to treat wireless systems as independent access networks requiring the user to handle aspects of roaming between disparate wireless networks or is an internet model better where independent autonomous wireless systems (AWS) cooperate to form a single, unified cloud to users, with network level resource allocation? Second, is it better to have dedicated, low power circuitry that supports a limited set of independent wireless Radio Access technologies (RATs) or is it better to build agile handsets that adapt (reconfigure) in real-time to operate over a large range of RAT technologies and operating modes? The results in this paper shed light on these questions. We present preliminary results from a MATLAB-based simulation study that highlights the increase in spectral efficiency as the modality of devices increase. Our analysis takes into account the cost of radio reconfiguration in terms of the temporary communications downtime and the surge of power that occurs with each reconfiguration operation. Our main result suggests that nomadic users benefit the most primarily due to their ability to route traffic over 'hotspot' type of RATs that tend to have high data rates at reduced coverage, and that this in turn helps increase the 3G or 4G bandwidth available to mobile users. All nodes in the system experience an increase in spectral efficiency ranging from 14% to 75% when compared to a similar scenario that assumes no network cooperation and static radios. © 2011 IEEE.