Precoding for scalable cell-free massive MIMO with radio stripes

Miretti, Lorenzo; Björnson, Emil; Gesbert, David
SPAWC 2021, 22nd IEEE International Workshop on Signal Processing Advances in Wireless Communications, 27-30 September 2021, Lucca, Italy

This paper studies a novel distributed precoding scheme for cell-free massive MIMO networks. Our scheme, coined team minimum mean-square error (TMMSE) precoding,
generalizes classical centralized MMSE precoding to arbitrary patterns of channel state information (CSIT) sharing among the transmitters. Building on the so-called theory of teams, we show that designing the optimal TMMSE precoders is equivalent to solving an infinite dimensional linear system of equations. We solve the problem explicitly for two important CSIT sharing patterns, i.e., the classical case of purely local CSIT and the
case of unidirectional CSIT sharing along a serial fronthaul. The latter scenario is relevant, e.g., for the recently proposed radio stripes concept. In both cases, our optimal design outperforms the heuristic methods that are known from the previous literature.
Duality arguments and numerical simulations validate the effectiveness of the proposed schemes in terms of ergodic achievable rates under a sum power constraint.

Systèmes de Communication
Eurecom Ref:
© 2021 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.