Spatial Spectrum Reuse for Heterogeneous Wireless Systems Coexistence

Cognitive radio is a means to solve the spectrum scarcity problem by allowing secondary spectrum users to share channels with the primary spectrum users in an opportunistic fashion. However, cognitive radio requires high costs in terms of spectrum sensing and monitoring system complexities as well as potential interference issues to the primary spectrum users. In this paper, we propose a spatial spectrum reuse scheme that arranges the deployments of secondary users far away from primary users so that the coexisting wireless systems on the same spectrum band cause negligible interferences to each other. Our scheme exploits the spectrum utilization characteristics of both worlds, thus eliminates the spectrum sensing or monitoring complexities. Specifically, we study the spatial spectrum reuse approach for the coexistence of the widely accepted and deployed GPRS and WiFi systems, both operating at the GSM 900 MHz RF bands. Experimental results show that the proposed scheme is a feasible approach to the spectrum scarcity problem.