Large-Scale-Fading Decoding in Cellular Massive MIMO Systems with Spatially Correlated Channels

Abstract

Massive multiple-input--multiple-output (MIMO) systems can suffer from coherent intercell interference due to the phenomenon of pilot contamination. This paper investigates a two-layer decoding method that mitigates both coherent and non-coherent interference in multi-cell Massive MIMO. To this end, each base station (BS) first estimates the channels to intra-cell users using either minimum mean-squared error (MMSE) or element-wise MMSE (EW-MMSE) estimation based on uplink pilots. The estimates are used for local decoding on each BS followed by a second decoding layer where the BSs cooperate to mitigate inter-cell interference. An uplink achievable spectral efficiency (SE) expression is computed for arbitrary two-layer decoding schemes. A closed-form expression is then obtained for correlated Rayleigh fading, maximum-ratio combining, and the proposed large-scale fading decoding (LSFD) in the second layer. We also formulate a sum SE maximization problem with both the data power and LSFD vectors as optimization variables. Since this is an NP-hard problem, we develop a low-complexity algorithm based on the weighted MMSE approach to obtain a local optimum. The numerical results show that both data power control and LSFD improves the sum SE performance over single-layer decoding multi-cell Massive MIMO systems.

arXiv comment17 pages; 10 figures; Accepted for publication in IEEE Transactions on Communications

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Cited by in corpus (8)

• Performance of Cell-Free Massive MIMO with Rician Fading and Phase Shifts
• Large-Scale Fading Precoding for Spatially Correlated Rician Fading with Phase Shifts
• Dynamic Resource Allocation in Co-Located and Cell-Free Massive MIMO
• On Rate-Splitting With Non-unique Decoding In Multi-cell Massive MIMO Systems
• Performance of Multi-Cell Massive MIMO Systems With Interference Decoding
• Average SEP-Optimal Precoding for Correlated Massive MIMO with ZF Detection: An Asymptotic Analysis
• LSFD for Rician-Faded Cell-Free mMIMO Systems With Channel Aging and Hardware Impairments
• Power Control for Massive MIMO Systems with Nonorthogonal Pilots