In interference-tolerant CR networks, CR users can share the spectrum resource with a licensed system while keeping the interference below a threshold.
In comparison with interference-free CR networks, interference-tolerant CR networks can achieve enhanced spectrum utilization by opportunistically sharing the radio spectrum resources with licensed users, as well as better spectral and energy efficiency.
However, it has been shown that the performance of CR systems can be very sensitive to any slight change in user densities, interference threshold, and transmission behaviors of the licensed system.