In the current architecture of dynamic spectrum access, which is also known as opportunistic spectrum access, secondary users (SU) only opportunistically access the spectrum of primary users. The resurgence of primary users (PU) disrupts on going communication of SU, which can result in poor performance for SU. In this thesis, an architecture for dynamic spectrum access, termed Dynamic Spectrum Co-Access (DSCA), is implemented to enable the PU and the SU to simultaneously access licensed spectrum. With DSCA, SU transparently incentivize primary users through increasing the PU performance, so that SU can access spectrum simultaneously with PU; hence there is no disruption to secondary communications due to the resurgence of PUs. A mathematical model is formulated to calculate the minimum incentives for the spectrum co-access between the PU and the SU, and the region of co-access is computed to determine the SU that can co-access with a given PU. Special pre coding techniques called Dirty Paper Coding (DPC) is used to preserve signal over the interference for secondary network. A mathematical model is formulated to determine the minimum incentives for the spectrum co-access; and a computational analysis of region of the co-access is performed to determine whether the SU can co-access with a given PU. The result reveals that the model is able to show the SU can co-access with PU without impairing the performance of PU and even finding some space for itself.