System performance enhancement using Power Path Gain Ratio for Cognitive Radio systems with diverse transmission ranges

The interaction between two cognitive radio systems with diverse transmission ranges using different strategies is investigated in this paper. The long range system uses a power efficiency (PE) based resource assignment that allows users to use many channels with a low modulation scheme. The short range system employs a bandwidth efficiency based scheme operating with a high modulation scheme and the smallest number of channels. Both systems share a set of OFDM channels based on a power path gain ratio (PPGR) strategy, which provides a novel and direct measurement of the impact on victim receivers from a new transmitter activation and balances it with the benefit to the transmitting system. It is shown that both schemes interact well based on the PPGR strategy.