STAC: Simultaneous transmitting and air computing in wireless data center networks

The data center network (DCN), wired or wireless, features large amounts of Many-to-One (M2O) sessions. Each M2O session is currently established using Point-to-Point (P2P) communications and Store-and-Forward (SAF) relays, and is generally followed by a certain computation at the destination, typically a weighted summation of the received information digits. Fundamentally different from this separate P2P/SAF-based-transmission and computation framework, this paper proposes STAC, a novel physical layer scheme that achieves Simultaneous Transmission and Air Computation in wireless DCNs. In particular, STAC builds on a number of distinguishing characteristics of DCs to take advantage of the superposition nature of electromagnetic signals. With STAC, multiple sources transmit in the same time slot with appropriately chosen parameters, such that the superimposed signal can be directly transformed to the desired summation at the receiver. To enable STAC, we propose an enhanced Software Defined Network (SDN) architecture, where a wired low-bandwidth backbone provides wireless transceivers with external reference signals. Theoretical analysis and simulation results show that STAC can significantly improve both bandwidth and energy efficiency in DCNs.