Underlay spectrum sharing with adaptive interference cancelation at primary and secondary receivers

Abstract

For the underlay spectrum sharing, a primary transmitter (PT) and a secondary transmitter (ST) can transmit simultaneously to a primary receiver (PR) and a secondary receiver (SR), respectively. The transmit power of ST is strictly controlled under the performance constraint of primary system. The strong interference from PT and the weak signal from ST make the communication quality of secondary system very poor, especially when the two systems are close. In this work, we adopt the successive interference cancellation (SIC) technique at either or both of PR and SR for the data detection. Four spectrum sharing schemes are studied, i.e., PR–DIR–SR–DIR, PR–DIR–SR–SIC, PR–SIC–SR–DIR, PR–SIC–SR–SIC. The transmit power of ST is properly set to minimize the secondary outage probability subject to a performance-loss constraint of primary system. Numerical results show that the SIC decoding can significantly improve the spectral efficiency, especially when PR performs the SIC decoding.