The invention relates to a
secure transmission method adopting information source and
relay-combined transmitting antenna selection. The method includes the following steps that: in a first time slot, and an information source obtains
channel state information from a
relay and selects an antenna which makes the received
signal to
noise of the
relay maximum to broadcast confidential signals according to the
channel state information, and other three nodes receive signals through adopting maximal-ratio combining; in a second time slot, the relay adaptively
decodes a forwarding protocol, when the relay can correctly decode the forwarding protocol, the relay obtains
channel state information from an information sink and selects one antenna which makes the received
signal to
noise of the information sink maximum to forward confidential signals according to the channel state information from the information sink; and when the relay cannot correctly decode the forwarding protocol, the information source obtains the channel state information from the information sink and selects an antenna which makes the received
signal to
noise of the information sink maximum to retransmit the confidential signals in the first time slot, and the information sink and the relay receive the signals with maximal-ratio combining. According to the method of the invention, transmitting antenna selection technology is adopted to maximize the received
signal to noise ratio of the relay or the information sink, and the received
signal to noise ratio of an eavesdropper can be decreased, and
low complexity and
high security can be achieved.