Weighted Graph Coloring Based Softer Pilot Reuse for TDD Massive MIMO Systems | IEEE Journals & Magazine | IEEE Xplore

Weighted Graph Coloring Based Softer Pilot Reuse for TDD Massive MIMO Systems

Publisher: IEEE

Abstract:

In a massive multiple-input multiple-output (MIMO) system, the serious pilot contamination problem severely restricts its ability to boost the spectrum utilization. To ta...View more

Abstract:

In a massive multiple-input multiple-output (MIMO) system, the serious pilot contamination problem severely restricts its ability to boost the spectrum utilization. To tackle this problem, the conventional concept of softly reusing the spectrum resources for the inner regions of the neighboring cells has been extended to reuse the pilot resources so as to accommodate more users. Alternatively, properly selecting the users to reuse the pilots among the neighboring cells can alleviate the pilot contamination problem as well. In this paper, we delicately integrate these two concepts to properly reuse the pilots allocated to the outer regions of the cells. By well designing the hazard- and secure-edge regions to manage the pilot reuse, the increment of interference can be effectively suppressed, and, consequently, the more accommodated users can contribute to the remarkably higher sum data rates. Furthermore, via some adaptive power adjustment for the users within different regions, the user data rates can further be significantly enhanced.
Published in: IEEE Transactions on Vehicular Technology ( Volume: 67, Issue: 7, July 2018)
Page(s): 6272 - 6285
Date of Publication: 22 March 2018

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Publisher: IEEE

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I. Introduction

The massive multiple-input multiple-output (MIMO) transmission technology has certainly emerged as one of the most important innovation for the next generation of wireless communication systems [1] . By well composing a large number of antennas on a site unit, the huge amount of space resources can be created so that multiple users can simultaneously share the whole time-frequency resources. Generally, the time division duplex (TDD) scheme is suggested for the massive MIMO systems since the property of channel reciprocity can facilitate the channel estimations [2]. However, the limited time-slot resources (i.e., the coherent interval) restricts the number of available pilot sequences for conducting the channel estimation. Accordingly, the necessary pilots reuse among cells unavoidably results in the serious pilot contamination problem [3].

References

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