On the Coordinated Multipoint Joint Transmission in Multi-UAV Sensor Networks

The realization of the UAV-assisted sensing networks is subject to the establishment of seamless connectivity while attaining a decent power and spectral efficiency. In this paper, a network of sensing UAVs is considered where we propose techniques to efficiently recover data in an asynchronous coordinated multipoint (CoMP) scheme. Due to the fast-changing topology in UAV networks, the delays from UAVs to the access point, in general, may exceed cyclic prefix (CP) length, causing symbol-asynchronous reception at the receiver. We investigate this problem in an information theoretic approach. We derive the capacity region and show that by exploiting the asynchronous channels’ memory and correlation, the spectral efficiency can exceed that of non-cooperative reception, provided that the proper receiver is used. We characterize the mathematical model for the asynchronous fading channel in the context of a CoMP network. Moreover, we show that while successive interference cancelation (SIC) receiver is sensitive to the non-coherent reception, the performance elevates in the iterative joint detection and decoding (IJDD) receiver. We use a low-complexity detection scheme targeting minimizing the mean square error (MMSE) and adopt it in our asynchronous fading channel model. Our extensive simulations validate the proposed scheme providing a considerable boost in the channel reliability while increasing the spectral and power efficiency, even as the number of UAVs increases.