Spectrum sharing with limited feedback in poisson cognitive network

In this paper, we propose a limited feedback based underlay spectrum sharing scheme in a Poisson cognitive network. Both primary and secondary transmitters are Poisson distributed nodes with limited feedback of channel quality information from their local receivers. The primary and secondary transmitters are elected to transmit if their local channel gains are above certain thresholds. Closed-form optimal node density of primary user is obtained analytically by maximizing the primary area spectral efficiency under the primary outage constraint. In addition, closed-form optimal node density of the secondary user is derived by maximizing the secondary area spectral efficiency under the secondary outage constraint and primary efficiency loss constraint, where the primary efficiency loss constraint guarantees the degradation of the area spectral efficiency of primary user is within a tolerable threshold. Numerical results show the maximized area spectral efficiency of secondary user increases as the increase of the secondary outage constraint before it is flattened out by the primary efficiency loss constraint.