Compact Ultra Massive Array (CUMA) with 4 RF Chains for Massive Connectivity
Kai‐Kit Wong
Abstract
The bottleneck for massive connectivity is the need of acquiring accurate channel state information (CSI) from all the users at the transmitter side so that multiuser signals can be nicely placed into orthogonal subspaces for spatial multiplexing. Recently, a transmit CSI-free multiple access technique, referred to as fluid antenna multiple access (FAMA), has been introduced exploiting the unique position reconfigurability of fluid antenna system (FAS). In this paper, we consider one particular version of FAMA, referred to as compact ultra massive array (CUMA). Motivated by the fact that a mobile device operating in the 5G core band has 4 radio-frequency (RF) chains, this paper extends CUMA to exploit all 4 RF chains for improved performance.