PDRS: A Fast Non-iterative Scheme for Massive Grant-free Access in Massive MIMO

TL;DR

This paper introduces PDRS, a non-iterative, low-complexity scheme for massive grant-free access in MIMO systems, enabling efficient user detection and channel estimation without iterative processes.

Contribution

The paper proposes PDRS, a novel non-iterative method that significantly reduces complexity in grant-free massive MIMO access by eliminating iterative detection and direct weight estimation.

Findings

Performance comparable to existing methods

Complexity reduced by orders of magnitude

Effective pilot activity detection

Abstract

Grant-free multiple-input multiple-output (MIMO) usually employs non-orthogonal pilots for joint user detection and channel estimation. However, existing methods are too complex for massive grant-free access in massive MIMO. This letter proposes pilot detection reference signal (PDRS) to greatly reduce the complexity. In PDRS scheme, no iteration is required. Direct weight estimation is also proposed to calculate combining weights without channel estimation. After combining, PDRS recovery errors are used to decide the pilot activity. The simulation results show that the proposed grant-free scheme performs good with a complexity reduced by orders of magnitude.