This section provides background information related to the present disclosure which is not necessarily prior art.
Coordinated multiple point transmission (CoMP) technology is a coordination between multiple geographically separated transmission points. The multiple transmission points can be base stations of different cells or can be multiple separated transmission equipment within a single cell. The CoMP technology can be mainly divided into two categories: CS/CB (Coordinated Scheduling/Beamforming) and JP (Joint Processing).
CS/CB uses the coordination of time, frequency, and space resources between cells to distribute mutually orthogonal resources for different user equipments (UEs), in order to prevent interference between each other. Because the interference between cells is the main reason limiting the performance of edge UEs of the cells, CS/CB can improve the performance of the edge UEs of the cells through lowering the interference between the cells.
FIG. 1 is a diagram of CS/CB. Through joint scheduling of three cells, three possible interfering UEs can be dispatched onto mutually orthogonal resources (namely, onto different resources which include time, frequency, and space etc.), thereby effectively preventing interference between the cells.
The difference between the JP scheme and the CS/CB scheme is that the JP scheme can send data to a UE from multiple cells simultaneously in order to enhance the received signal of the UE. As shown in FIG. 2, which is a diagram of JP, three cells send data to a UE on the same resource, and the UE simultaneously receives signals from the multiple cells. If all of the coordinating cells send the same data to the UE, then the useful signal from the multiple cells will be superimposed to improve signal reception quality of the UE. Thus, demodulation performance of UEs, especially the performance of edge UEs of the cells, may be improved.
In the current technology, a special form of the JP scheme is dynamic transmission point selection. That is, a transmission point for sending data to a UE is dynamically selected based on channel conditions between the UE and the transmission point, and each time one transmission point sends data to the UE. FIGS. 3A and 3B are diagrams of the dynamic transmission point selection. In FIG. 3A, transmission point 1 is selected as the transmission point from which to send data to the UE. In FIG. 3B, transmission point 2 is selected as the transmission point from which to send data to the UE.
In the process of implementing the present disclosure, it was discovered that at least the following issues exist in the current technology: there is not a suitable method by which to send feedback for every scheme (CS/CB, JP, dynamic transmission point selection, etc.) in the current technology.