PRADA: Practical Access Point Deployment Algorithm for Cell-Free Industrial IoT Networks

Ki-Hun Lee, Hyang-Won Lee, Howon Lee, Bang Chul Jung

Abstract: We propose a novel practical access point (AP) deployment technique for 6G ultra-reliable industrial Internet-of-things (IIoT) networks. In particular, a cell-free massive multiple-input multiple-output (CF -mMIMO) architecture is adopted to improve reliability with macro-diversity, where a station (STA) is simultaneously associated with and served by multiple APs. We first mathematically formulate an integer linear programming (ILP)-based optimization problem that minimizes the number of required APs while satisfying a certain quality-of-service (QoS) of IIoT networks, such as the minimum number of concurrent communication links and the minimum required signal-to-noise ratio (SNR). However, the optimal technique requires significant computational complexity and time, unfortunately. Hence, we propose a low-complexity AP deployment algorithm based on parallel search methods, named PRADA. The proposed algorithm sufficiently reduces the number of required APs in a computationally efficient manner while satisfying the QoS constraints.