Adaptive pilot reuse scheme for nonzero neighborhood structured downlink channel in massive MIMO

Sanaz Rezvani Kenarsari | Mahmoud Ferdosizade Naeiny

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URL :   http://research.shahed.ac.ir/WSR/WebPages/Report/PaperView.aspx?PaperID=95865
Date :  2019/02/01
Publish in :    AEU-International Journal of Electronics and Communications
DOI :  https://doi.org/10.1016/j.aeue.2018.11.020
Link :  http://dx.doi.org/10.1016/j.aeue.2018.11.020
Keywords :Adaptive, pilot, structured, downlink, MIMO

Abstract :

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This study investigates the pilot contamination (PC) effect as the main bottleneck of time division duplex (TDD) massive multi-input multi-output (MIMO) systems. Based on sparsity properties of the angular representation of channel, a compressed sensing (CS)-based algorithm is proposed to estimate the channel response. It is demonstrated that the proposed channel estimation method can efficiently eliminate PC under certain conditions. To provide the PC elimination conditions, an adaptive pilot assignment (PA) scheme is designed based on non-zero neighborhood (NZN) structure of channel in beam domain. Despite of previous PA schemes, where a pilot sequence is surly reused by users of different cells, the proposed method assigns the same pilot sequence to the users with non-overlapped NZN, despite of being at the same cell or not. In the proposed PA method, the required length of pilot is adaptively obtained based on the PC severity in the system. Simulation results illustrate that compared to previous PA algorithms, the proposed scheme achieves better performance in terms of sum rate and the average pilot length.