Distributed MIMO Transmission With Intra-RRH Precoding and Inter-RRH Diversity

The patent segments the distributed MIMO system into multiple Remote Radio Heads (RRHs), where each RRH independently performs channel estimation and precoding operations. This segmentation divides the complex overall channel estimation problem into smaller, manageable sub-problems at each RRH, reducing the computational complexity while maintaining the benefits of distributed MIMO transmission.

The patent applies preliminary precoding at each RRH based on local channel state information before transmission. By performing precoding in advance at each distributed RRH, the system simplifies the overall channel estimation required at the receiver, as the precoding compensates for channel effects beforehand, reducing the complexity of equalization and channel estimation at the UE.

The patent merges two transmission schemes: intra-RRH precoding (spatial multiplexing within each RRH) and inter-RRH diversity (coherent combining across multiple RRHs). By combining these schemes in a unified framework where each RRH applies precoding locally and the UE combines signals from multiple RRHs, the system achieves both spatial multiplexing gain and diversity gain, improving transmission robustness while managing complexity through modular design.

The patent applies different processing strategies at different locations: intra-RRH precoding is applied locally at each RRH based on local channel conditions, while inter-RRH diversity combining is performed at the UE based on received signals from multiple RRHs. This local quality approach allows each component to be optimized independently, improving overall reliability without requiring centralized control of the entire system.