2019, 28(1): 143-151.
doi: 10.1049/cje.2018.11.007
Abstract:
By combing Spatial modulation (SM) with the Amplify-and-forward (AF) cooperative communication, a cooperative SM scheme with AF (AF-SM) protocol is presented, and the corresponding Bit error rate (BER) performance is investigated. Based on the performance analysis, the error probability of antenna index estimation (Pa) and the error probability of symbol estimation (Pd), which constitutes the overall average BER, are derived, respectively. As a result, tightly approximate closedform expressions of Pa and Pd are attained, respectively. Using these expressions, the closed-form overall average BER is achieved. During the analysis, the computational complexity of AF-SM detector is also provided in terms of the complex addition and multiplication numbers. Besides, the asymptotic BER at high SNR and the corresponding diversity gain are further derived, and the resultant diversity gain of Nr + 1 is obtained for the system with Nr receive antennas. Simulation results show that our theoretical analysis is valid, and provides good performance evaluation method for cooperative SM system. Moreover, the BER performance can be effectively improved as Nr increases due to higher diversity gain.