A throughput study of grant-free multiple access for massive wireless communications

As a demand of diverse services and a rapid increase of Internet of Thing (IoT) devices, it requires a new medium access control (MAC) to support a massive and variable IoT devices in the next generation wireless communications. As the viewpoints of simplicity, flexibility and scalability, a contention-based multiple access (CMA) is a potential function of MAC in the massive wireless communications. So that a grant-free multiple access (GFMA) method as a new CMA has been proposed to provide a simultaneous massive connectivity and to reduce the latency of data transmission. This paper introduces a novel GFMA and studies the performance of GFMA throughput numerically. In addition, we conduct the performance comparison the proposed GFMA with the legacy CMAs such as slotted aloha (SA) and grant multiple access (GMA) of LTE random access channel (RACH) and shows that the proposed GFMA achieves a higher throughput rather than others.