C-RAN-Type Cluster-Head-Driven UAV Relaying With Recursive Maximum Minimum Distance

In this letter, a Cloud Radio Access Network-type cluster-head-driven uplink model for multiple-antenna Unmanned Aerial Vehicles (UAV) relaying schemes is presented, which enables joint Maximum Likelihood symbol detection in the UAV cluster-head and the selection of UAV sources to communicate with each other aided by UAV-based relays. A relay selection technique, named Cluster-Head-Driven Best-Link (CHD-Best-Link), which employs cluster-head buffers and physical-layer network coding, is devised. A recursive maximum minimum distance relay selection strategy that exploits time-correlated channels and equips the CHD-Best-Link scheme is also developed. Simulations illustrate that CHD-Best-Link has superior average delay and bit error rate performances to that of previous schemes.