Spectrum sharing between a ZigBee frequency hopper and an FSK modem

Allowing multiple users to transmit in the same band simultaneously in an uncoordinated manor may require agility and reaction on the part of one or both of the users. In the scenario we consider here, one of the users is considered a primary user (PU) and will not react to the secondary user (SU). The SU is responsible for maximizing the combined channel throughput while minimizing interference to the PU. The scenario we examine has a PU operating in a frequency span of 20 MHz occupying a nominal 5 MHz Bandwidth centered at one of the offsets of ±2.5 MHz or ±7.5 MHz from band center. The PU randomly hops between these band centers. The SU can monitor the PU spectral position and respond with appropriate changes to its transmitted signal position to minimize interfering transmissions. We designed our SU signal to overlay the PU without the need to monitor and avoid the PU´s occupied band while preserving negligible interaction between the signal sets.