Scalable Uplink Combining in Cell-Free Massive MIMO under Practical Fading and Centrized Processing
DOI:
https://doi.org/10.65568/gujes.2026.020105Keywords:
Massive MIMO, MMSE, P-MMSE, ZF, RZF, TPE-MR, TPE-MMSE, SE, CDFsAbstract
In this paper, we conducted a performance study of uplink combining algorithms for Cell-Free Massive MIMO, a future wireless technology aimed at removing cell boundaries to reduce inter-cell interference. In contrast to traditional Massive MIMO, Cell-Free deployments adopt multiple distributed access points (APs) that cooperate to serve users, thereby increasing spectral efficiency (SE) and service fairness. We analyze centralized combining schemes such as MMSE, MR, ZF, and RZF under both Rayleigh and Rician fading environments, considering fronthaul and complexity constraints. System-level simulations evaluate SE behavior for different numbers of APs and antennas. Comparisons indicate that the MMSE and RZF have achieved SE but with higher complexity. The 90%-likely SE is used as a measure of fairness and reliability.
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