Iterative Detection and Decoding for Clustered Cell-Free Massive MIMO Networks
T. Ssettumba, S. Mashdour, L. Landau, P. da Silva, R. C. de Lamare
TL;DR
This work tackles the performance degradation from intra-cluster and out-of-cluster interference in user-centric clustered CF-mMIMO uplinks. It proposes an integrated approach consisting of an MMSE receive filter with a modified PIC to cancel both ICL and OCL streams, a least-squares estimator for OCL interference, and an LDPC-based iterative detection and decoding (IDD) chain with a Gaussian-approximation receiver. Key contributions include a projection-based OCL estimation strategy leveraging $\tau_p > K+M$, a scalable modified PIC receiver, and a tractable IDD with box-plus SPA, achieving notable BER and NMSE gains over baselines. The results indicate practical improvements for interference management in scalable CF-mMIMO deployments, with implications for pilot design and receiver complexity.
Abstract
In this letter, we propose an iterative soft interference cancellation scheme for intra-cluster (ICL) and out-of-cluster (OCL) interference mitigation in user-centric clustered cell-free massive multiple-antenna networks. We propose a minimum mean-square error receive filter with a novel modified parallel interference cancellation scheme to mitigate ICL and OCL interference. Unlike prior work, we model the OCL interference and devise a least squares estimator to perform OCL interference estimation. An iterative detection and decoding scheme that adopts low-density parity check codes and incorporates the OCL interference estimate is developed. Simulations assess the proposed scheme against existing techniques in terms of bit error rate performance.
