Channel Reconstruction via Quadratic Programming in Massive MIMO Networks

Reconfigurable Intelligent Surface: Design the Channel -- a New Opportunity for Future Wireless Networks

“…On the other hand, given channel links having non-LoS components and where finer control of RIS elements is possible, explicit channel reconstruction becomes important as we seek to realize the gains achievable via an optimized RIS pattern. For such reconstruction, an interesting avenue for research would be to extend the non-convex quadratically constrained quadratic programming based FDD massive MIMO channel reconstruction proposed in [69], which combines subspace side-information with limited instantaneous quantized feedback information. In this context, we note that dictionary based interpolation approaches for inferring downlink covariance (and hence downlink subspace information) based on observed uplink estimates have been gainfully exploited over conventional massive MIMO communications [70].…”