Abstract:With the proposed network coding technol ogy and research on wireless interference channels, the physical layer network c oding for wireless multi source information is proposed, which can effectively m ix interference and improve the spectrum efficiency of wireless networks. This article introduces the physical layer network coding for wireless cooperative net works from the research background and advancement of physical layer ne twork coding. Specifically, some typical analog network co ding and digital network coding of multi source relay systems are introduced starting from rel a y technologies. Some of the authors′ work is also included. The paper provides a reference for the research in the areas of relay communications and wireless network coding.