Smart Pilot Assignment for Massive MIMO

TL;DR

This paper proposes a smart pilot assignment scheme for massive MIMO systems that leverages large-scale fading characteristics to reduce pilot contamination and enhance user performance, especially for those with poor channel quality.

Contribution

The paper introduces a novel pilot assignment method that assigns pilots based on inter-cell interference levels, improving performance over conventional random schemes.

Findings

Significant performance improvement in massive MIMO simulations.

Effective reduction of pilot contamination through interference-aware assignment.

Enhanced user fairness, especially for users with poor channel conditions.

Abstract

A massive multiple-input multiple-output (MIMO) system, which utilizes a large number of antennas at the base station (BS) to serve multiple users, suffers from pilot contamination due to inter-cell interference. A smart pilot assignment (SPA) scheme is proposed in this letter to improve the performance of users with severe pilot contamination. Specifically, by exploiting the large-scale characteristics of fading channels, the BS firstly measures the inter-cell interference of each pilot sequence caused by the users with the same pilot sequence in other adjacent cells. Then, in contrast to the conventional schemes which assign the pilot sequences to the users randomly, the proposed SPA method assigns the pilot sequence with the smallest inter-cell interference to the user having the worst channel quality in a sequential way to improve its performance. Simulation results verify the performance gain of the proposed scheme in typical massive MIMO systems.