Abstract: A scheme of transparent transponder based on TDM/FDMA satellite communication system with star-type topology is proposed,where the spectrum of the both links are overlapped to share the same frequency band.The multi-access mode in the forward link from the user terminals to the hub station is FDMA,while the multiplexing mode of the forward link from the hub station to the user terminals is TDM.The paper analyzes in depth on the characteristics of the system,including a lot results of performance testing sim...