Collision Resolution Capability Analysis and Improved Receiver Design of Resource Hopping Multiple Access for the mMTC System

Massive machine-type communications are the key enabler for future Internet of Things applications in the fifth and sixth generation networks. To achieve low latency in mMTC systems, grant-free random access is employed to reduce control signaling overhead. However, a primary challenge is data collisions among active users due to limited channel resources. To address this, new multiple access techniques are essential. This paper introduces resource hopping multiple access for grant-free random access in mMTC. In RHMA, user data packets are segmented and mapped to multiple channel resources, effectively resolving collisions. Theoretical analysis of the collision resolution capability of RHMA is provided. Also, an improved receiver design incorporating successive interference cancellation is proposed to further improve collision resolution. Numerical simulations validate the analysis of resolution capability, demonstrating that RHMA supports reliable grant-free random access for massive users. Moreover, the improved receiver design is verified to boost the collision resolution performance.