Over-the-Air Computing in OFDM Systems

In next-generation networks, computing and related applications are expected to be enabled by communications. To accommodate a large number of devices and achieve better resource utilization, over-the-air (OTA) computing has been proposed as an attractive scheme to enable efficient computing. As such, OTA computing could be a candidate for computing applications that are susceptible to frequency-selective fading channels. In current communication systems, orthogonal frequency division multiplexing (OFDM) is the most common approach for dealing with such fading conditions, thus it is important to investigate whether a similar approach can be used for OTA computing. With this in mind, we model an orthogonal frequency domain (OFD) multi-user system where the users utilize OTA computing in each subcarrier. To account for practical scenarios, we study the presence of inter-carrier interference (ICI) among the subcarriers, and an optimization problem is formulated and solved to extract the optimal power allocation policy based on the statistics of the frequency error for the proposed OFD OTA computing system.