Optimum transmission of secondary user for spectrum sharing on interference channel

This paper presents optimum transmission strategies in terms of the number of transmission antennas and pilot symbols for secondary users of multiple-input and multiple-output system. By complying with the restriction of transmission power from geo-location database, secondary users can protect primary users. However, the receiver of secondary users can suffer from the interference by primary users. We derive a closed-form expression on achievable throughput of zero-forcing linear processing in the presence of channel estimation error due to interference and noise. In addition, we provide optimal values for transmission parameters in the condition of permitted power level and frame duration. With numerical results, we verify our analysis and discuss the effect of the transmission parameters.