An effective method for increasing the efficiency of the netwok in the MIMO systems

In this paper, a downlink system with cellular characteristics and two-way frequency division is considered which each user sends the information of status of information chanel to the home station. Since the collaboration between all the stations practically is not possible, a number of stations are classified into the clusters. Users should estimate their channel by sending pilots to the center station, and sending feedback of channel information. On the other hand, the station refuses to send the information, until it recives all information of users. This action leads to delation in transmission of information in downlink. In this research, four methods for reducing the information feedback of channel status in downlink system are proposed. The main idea of the proposed methods including the division the users into two groups based on the power of user channels and user distances from the transmitter station. The key issue in CoMP is that channel status information should be collected in a small fraction of the channel's binding time, so that it has enough time to send information. Using simulation, it is observed that the effect of the proposed methods to reduce the feedback of channel status information on system performance is very low compared to other methods.