In a single-source modulation retro-reflector (MRR) free-space optical (FSO) system,the downlink signal causes crosstalk to the uplink remodulation signal of MRR terminal received by transceiver terminal,causing the system′s bit error rate performance to deteriorate.In this paper,we propose to use combinatorial logic (CL) inverse pulse position modulation (IPPM) scheme to eliminate the crosstalk of the downlink signal to the uplink remodulation signal to reduce the bit error rate of the single-source MRR FSO communication system.In this study,we built a CL-IPPM-based single-source MRR FSO communication experiment platform,and did simulation and full-duplex communication experiment based on it.The results show that the single-source MRR FSO communication system using the CL-IPPM scheme has a gain of about 5 dB.Furthermore,when the transceiver terminal and MRR terminal adopted IPPM, CL-IPPM scheme has the best bit error rate performance.In addition,we used the pseudo-phase conjugation property of the micro-corner cube retro-reflector array to improve the robustness of the MRR FSO system, and combining the CL-IPPM and the micro-corner cube retro-reflector array, the full-duplex communication based on single-source MRR FSO system can be realized with a bit error rate of 10－3 or less under weakly and medium turbulent environment.