Blind Multi-user Detection Based on Receive Beamforming for Autonomous Grant-Free High-Overloading Multiple Access

Massive number of IoT devices are expected to simultaneously connect to the massive machine type communication and beyond future generations of wireless network, posing severe challenge to aspects such as random access procedure, user equipment detection and channel estimation. Although spatial degree of freedom can provide significant overloading in conventional grant-based transmission, its leverage is hard under autonomous grant-free transmission mechanism tailored for IoT use cases. To address this, blind spatial combining and its incorporation in the data-only multi user detection are elaborated in this paper answering to both the academic and industry's concern in the overloading potential of autonomous grant-free transmission. Blind spatial combining could be interpreted as blind receive beamforming heuristically. Simulation results show that the blind spatial combining enhanced data-only multi-user detection performance for AGF transmission is rather impressive.