Ultra-Reliable and Low-Latency Communications Using Proactive Multi-cell Association
To attain reliable communications traditionally relies on a closed-loop methodology but inevitably incurs a good amount of networking latency thanks to complicated feedback mechanism. Such a closed-loop methodology thus shackles the current cellular network with a tradeoff between high reliability and low latency. To completely avoid the latency induced by closed-loop communications, this paper aims to study how to jointly employ open-loop communications and multi-cell association in a heterogeneous network (HetNet) so as to achieve ultra-reliable and low-latency communications (URLLC). We first introduce how URLLC mobile users in a large-scale HetNet adopt the proposed proactive multi-cell association (PMCA) scheme to form their virtual cell that consists of multiple access points (APs) and then analyze the communication reliability and latency performances. We show that the communication reliability can be significantly improved by the PMCA scheme and maximized by optimizing the densities of the users and the APs. The analyses of the uplink and downlink delays are also accomplished, which show that extremely low latency can be fulfilled in the virtual cell of a user if the APs are deployed sufficiently for a given user density and the radio resources of each AP are appropriately allocated.
READ FULL TEXT