Hi @Guangyu_D
They seems to be pretty different, since RPMsg is not supported with S32G we do not have the knowledge to support it.
I have found these documents that could provide you more details regarding RPMsg and IPC, maybe they can help you with more details.
RPMsg
IPCF
IPCF page
According to the block diagram both systems works differently.
Since this seems that is all the information we currently have, I recommend you to contact your DFAE or nxp representative, they might have more information.
I apologize for the inconvenience.
Best Regards, Miguel.