Max-Min Fairness for Wireless-Powered Spatially Correlated Massive MIMO Multi-way Relaying

We consider a multi-way massive multi-input multi-output (mMIMO) relay via which several energy-constrained MIMO users exchange information by switching between wireless power generation and information transfer. The mMIMO relay and MIMO users experience spatially-correlated channels, which the current multi-way relaying literature ignores. We derive closed-form spectral efficiency (SE) expression for this system that is valid for a practical number of relay antennas. We design a max-min power control algorithm which ensures user fairness by jointly optimizing the charging time and transmit powers of the relay and users.