Optimal Resource Allocation of Orthogonal Relay-eavesdropper Channel

The orthogonal relay-eavesdropper channel is investigated. The source communicates with the relay and the destination in channel 1, the relay communicates with the destination in channel 2, channel 1 and channel 2 are orthogonal with each other. The secrecy rate is derived based on the analysis of parallel relay-eavesdropper channel. Under the limit of the total channel resource, the maximal secrecy rate is obtained through optimizing the resource allocation parameter alpha. In the Gaussian channel, when eavesdropper listen the signals of channel 1, it is proved that there exists the unique alpha to reach the maximum secrecy rate and a higher secrecy rate can be achieved using the optimal resource allocation strategy than the equal resource allocation strategy.