Autonomous Grant-Free High Overloading Multiple Access Based on Conjugated Data Symbols
Zhifeng Yuan, Yuzhou Hu, Yihua Ma, Weimin Li, Zhigang Li · 2020
This paper proposes a novel data-only transceiver targeting autonomous grant-free high overloading transmission under Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing waveform. At the transmitter side, key innovations include channel structure constituting conjugated data symbol pairs without reference signal overhead as well as collision-mitigating symbol level scrambling techniques. The receiver end contains key modules such as blind receive beamforming, blind sequence detection, blind Minimum Mean Square Error despreading as well as channel estimation modules leveraging the conjugated data symbol pairs. Additionally, a phase ambiguity issue related to channel estimation is discussed and resolved. Simulation results under Tapped Delay Line-C channel with realistic timing offset modelling show the proposed transceiver indeed achieves impressive overloading under autonomous grantfree setting.