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 minimization under a secrecy rate constraint. F... https://www.jmannino.com/quick-save-Canon-imageCLASS-MF227dw-Monochrome-Multifunction-Laser-Printer-great-choice/