A D2D-Based Protocol for Ultra-Reliable Wireless Communications for Industrial Automation

Abstract

As an indispensable use case for the 5G wireless systems on the roadmap, ultra-reliable and low latency communications (URLLC) is a crucial requirement for the coming era of wireless industrial automation. The key performance indicators for URLLC stand in sharp contrast to the requirements of enhanced mobile broadband (eMBB): lowlatency and ultra-reliability are paramount but high data rates are often not required. This paper aims to develop communication techniques for making a paradigm shift from the conventional human-type broadband communications to the emerging machine-type URLLC. One fundamental task for URLLC is to deliver short commands from a controller to a group of actuators within the stringent delay requirement and with high-reliability. Motivated by the factory automation setting in which tasks are assigned to groups of devices that work in close proximity to each other thus can form clusters of reliable device-to-device (D2D) networks, this paper proposes a novel two-phase transmission protocol for achieving URLLC. In the first phase, within the latency requirement, the multi-antenna base station (BS) combines the messages of all devices within each group together and multicasts them to the corresponding groups; messages for different groups are spatially multiplexed. In the second phase, the devices that have decoded the messages successfully, herein defined as the leaders, help relay the messages to the other devices in their groups. Under this protocol, we design an innovative leader selection based beamforming strategy at the BS by utilizing sparse optimization technique. The proposed strategy leads to a desired sparsity pattern in user activity with at least one leader being able to decode its message in each group in the first phase, thus ensuring full utilization of the reliability enhancing D2D transmissions in the second phase. Simulation results are provided to show that the proposed two-phase transmission protocol considerably improves the reliability of the entire system within the stringent latency requirement as compared to existing schemes for URLLC.

Toward Tactile Internet in Beyond 5G Era: Recent Advances, Current Issues, and Future Directions

“…The conventional broadcasting strategy in an industrial factory may not be efficient to satisfy the URLLC requirements due to the massive number of actuators to be supported. In this direction, authors in [192] proposed a two-phase transmission protocol by forming clusters of D2D networks to enable URLLC in 5G wireless systems.…”

Joint Power and Blocklength Optimization for URLLC in a Factory Automation Scenario

“…For example, in Industrial 4.0 [11], wired connection will be replaced by wireless transmission to enhance the flexibility and reduce the infrastructure cost. This change imposes challenging requirements on the wireless transmission in terms of latency and reliability [12]. For mission-critical tasks in FA, the transmission duration is expected to be lower than 100 µs to allow processing delays during queuing, scheduling, backhaul transmission, and propagation [13], while guaranteeing the packet error probability of 10 −9 .…”

Optimized Link Distribution Schemes for Ultrareliable and Low-Latent Communications in Multilayer Airborne Networks

“…In this scheme, multiple different interfaces have been applied to transmit the duplicate short packets to increase the reliability and decrease the latency, but the method to extend the interfaces has not been discussed. In [10] and [11], the authors proposed a system level protocol to optimize uRLLC. Several joint scheduling schemes to support uRLLC and eMBB have been proposed in [12], [13] and [14].…”