Secure Beamforming via Amplify-and-Forward Relays in Machine-to-Machine Communications
We consider the collaborative use of amplify-and-forward relays to form a beamforming system and provide physical layer security for a wireless machine-to-machine (M2M) communication network.We investigate two objectives: (i) the achievable secrecy rate maximization subject to the relay power constraint and (ii) the relay transmit power minimizatio