Comparison of bandwidth utilization for controlled and uncontrolled channel assignment in a spectrum pooling system

Spectrum for mobile networks is becoming scarce and on the other hand plenty of sporadically used frequencies exist. The spectrum utilization of such spectra is very low, which is a reason to think about a way to make them available for commercial purpose without a drawback for the license owners. We recommend a strategy called spectrum pooling which is based on this idea. The notion spectrum pool was first mentioned by Mitola III (see Proc. IEEE International Workshop on Mobile Multimedia Communications, p.3-10, 1999). In a spectrum pooling system the license owner of the spectrum allows priorly specified candidate renters to use his spectrum until he needs his spectrum himself. The renters of the spectrum may be treated in two different ways. One way is that communication processes of spectrum renters can persist as long as there are channels for the processes of the license owners. The other way is that the owner has no knowledge whether the channels are occupied by renters or not and treat the channels used by renters like free channels. In both cases the renters have to measure the interference level in the channel after dedicated time intervals and have to leave the channel within the time interval T/sub p/ as soon as the interference exceeds a prior specified threshold. We compare the spectrum utilization, blocking probability and forced termination probability for these two different channel access schemes.