Uplink scheduling of MU-MIMO gateway for massive data acquisition in Internet of things

Abstract

Due to the uplink-centric characteristic of diverse Internet of things (IoT) applications, the wireless connectivity for the IoT should provide a sufficient data rate for the delivery of a huge amount of data traffic toward the uplink direction; furthermore, it needs to satisfy the low complexity and high energy efficiency for the deployment of resource-constrained IoT devices. To this end, we propose an IoT uplink multiple-input and multiple-output (MIMO) scheduling scheme (IoT-UL-MIMO) for which a multi-user (MU)-MIMO capability is implemented in the IoT-gateway device to greatly extend the uplink bandwidth and support the massive data delivery from a plurality of devices toward the gateway. In the IoT-UL-MIMO, a simple user-selection process that selects a proper set of transmitters by just counting the number of successful control-frame transmissions from the devices is used without a channel-sensing mechanism. The aim of this design principle is a mitigation of the system complexity that reduces the energy consumption, which is a key consideration for resource-constrained IoT devices. The simulation results show significant improvements for the throughput and energy efficiency of IoT-UL-MIMO. A duration-length optimization regarding the uplink scheduling phase is also discussed in this paper.