Polynomial expansion of the precoder for power minimization in large-scale MIMO systems

Houssem Sifaou (1) , Abla Kammoun (2) , Luca Sanguinetti (3) , Merouane Debbah (4, 3) , Mohamed-Slim Alouini (2)

1 Ecole Polytechnique de Tunisie
2 KAUST - King Abdullah University of Science and Technology [Saudi Arabia]
3 LANEAS - Large Networks and Systems Group
4 Chaire Radio Flexible - Chaire Radio Flexible Alcatel-Lucent/Supélec

—This work focuses on the downlink of a single-cell large-scale MIMO system in which the base station equipped with M antennas serves K single-antenna users. In particular, we are interested in reducing the implementation complexity of the optimal linear precoder (OLP) that minimizes the total power consumption while ensuring target user rates. As most precoding schemes, a major difficulty towards the implementation of OLP is that it requires fast inversions of large matrices at every new channel realizations. To overcome this issue, we aim at designing a linear precoding scheme providing the same performance of OLP but with lower complexity. This is achieved by applying the truncated polynomial expansion (TPE) concept on a per-user basis. To get a further leap in complexity reduction and allow for closed-form expressions of the per-user weighting coefficients, we resort to the asymptotic regime in which M and K grow large with a bounded ratio. Numerical results are used to show that the proposed TPE precoding scheme achieves the same performance of OLP with a significantly lower implementation complexity.

Domaines: Théorie de l'information [cs.IT]

Houssem Sifaou, Abla Kammoun, Luca Sanguinetti, Merouane Debbah, Mohamed-Slim Alouini. Polynomial expansion of the precoder for power minimization in large-scale MIMO systems. ICC 2016 - 2016 IEEE International Conference on Communications, May 2016, Kuala Lumpur, Malaysia. ⟨10.1109/ICC.2016.7510948⟩. ⟨hal-01789334⟩