Ergodic Capacity of Spectrum Sharing Systems with OSTBC in Nakagami Fading

The spectrum sharing system employing orthogonal space-time block codes (OSTBCs) with both interference and transmit power constraints is analyzed in Nakagami fading environment, for an arbitrary number of transmit and receive antennas of the secondary user (SU). The closed-form expression for the probability density function of the signal-to-noise ratio at the SU receiver is derived. The ergodic capacity expression is derived in the exact closed-form under both interference and transmit power constraints. The analytical results are verified by using an independent simulation method.