Smart grid cooperative communications using switched relays with power allocation

In this paper, the cooperation communication with a modified switch-and-examine relay (SER) for the advanced metering infrastructure (AMI) is addressed, where fixed-gain amplify-and-forward (AF) relay is used since it consumes less power of relay processing and results in matched performance as compared to decode-and-forward (DF) relay. With the SER for smart grid cooperative communications, the relay is used only when the faded signal-to-noise ratio (SNR) of the direct transmission from the sensor or meter node to the meter data management center falls below a preset threshold. In the paper, the average transmission power of the cooperative communication with the modified SER is evaluated, and the optimal switch threshold is derived. In addition, optimal allocation of transmission powers for direct transmission and dual-hop relaying channels is considered. For the AMI system, numerical results of the optimal switch threshold and the minimum average transmission power are illustrated for the cooperation communication, where the relation between the optimal switch threshold and the minimum average transmission power is illustrated and different cases of fading parameters of wireless channels are studied.