Superimposed Pilots Are Superior for Mitigating Pilot Contamination in Massive MIMO

Karthik Upadhya, Sergiy A. Vorobyov*, Mikko Vehkapera

*Tämän työn vastaava kirjoittaja

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu

63 Sitaatiot (Scopus)

Abstrakti

In this paper, superimposed pilots are introduced as an alternative to time-multiplexed pilot and data symbols for mitigating pilot contamination in massive multiple-input multiple-output (MIMO) systems. We propose a non-iterative scheme for uplink channel estimation based on superimposed pilots and derive an expression for the uplink signal-to-interference-plus-noise ratio (SINR) at the output of a matched filter employing this channel estimate. Based on this expression, we observe that power control is essential when superimposed pilots are employed. Moreover, the quality of the channel estimate can be improved by reducing the interference that results from transmitting data alongside the pilots, and an intuitive iterative data-aided scheme that reduces this component of interference is also proposed. Approximate expressions for the uplink SINR are provided for the iterative data-aided method as well. In addition, we show that a hybrid system with users utilizing both time-multiplexed and superimposed pilots is superior to an optimally designed system that employs only time-multiplexed pilots, even when the non-iterative channel estimate is used to build the detector and precoder. We also describe a simple approach to implement this hybrid system by minimizing the overall inter- and intracell interference. Numerical simulations demonstrating the performance of the proposed channel estimation schemes and the superiority of the hybrid system are also provided.

AlkuperäiskieliEnglanti
Artikkeli7865983
Sivut2917-2932
Sivumäärä16
JulkaisuIEEE Transactions on Signal Processing
Vuosikerta65
Numero11
DOI - pysyväislinkit
TilaJulkaistu - 1 kesäkuuta 2017
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

Sormenjälki

Sukella tutkimusaiheisiin 'Superimposed Pilots Are Superior for Mitigating Pilot Contamination in Massive MIMO'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.

Siteeraa tätä