Reliable Over-the-Air Computation by Amplify-and-Forward Based Relay

In typical sensor networks, data collection and processing are separated. A sink collects from all nodes sequentially, which is very time consuming. Over-the-air computation, as a new diagram of integrates in one slot: transmit their signals simultaneously the analog wave done air. This method, although efficient, requires that arrive at sink, aligned signal magnitude so to enable an unbiased estimation. For far away with low channel gain, misalignment unavoidable. To solve this problem, paper, we investigate amplify-and-forward based relay, relay node amplifies many same time. We first discuss general model simple policy. Then, coherent policy proposed reduce transmission power. Directly minimizing computation error tends over-increase Therefore, two policies further refined metric, power reduced while kept low. addition, helps by half, below limit, makes it step ahead towards practical applications.