A two-step precoding method for a coordinated multipoint joint transmission system in a multi-user scenario

Abstract

The invention discloses a two-step pre-coding method of a cooperative multipoint united transmission system under a multi-user scene. The two-step pre-coding method of the cooperative multipoint united transmission system under the multi-user scene includes that firstly an optimizing target which is based on minimum interference leakage which is from a user to other users is built on a single base station through interface alignment processing and a first step pre-encoding matrix and a receiving matrix which aim at every user are respectively obtained through an alternating minimization method; and secondly the receiving matrix, the first step pre-encoding matrix which are received from the first step and aim at every user and a useful channel matrix are combined into an equivalent channel matrix, a corresponding phase rotary matrix is arranged on the equivalent channel matrix, and interferences between different antennas of every user are converted into a useful signal to effectively utilize the transmit power from every base station to the user and obtain a second step pre-encoding matrix and a final pre-encoding matrix. The two-step pre-coding method of the cooperative multipoint united transmission system under the multi-user scene has the advantages of being obvious in bit error rate decreasing, accelerating the downtrend of a bit error rate curve and obviously improving an average speed of a system.

Description

Technical field: [0001] The invention belongs to the field of wireless communication, and in particular relates to a two-step precoding method of a coordinated multi-point joint transmission system in a multi-user scenario. Background technique: [0002] The joint transmission technology in the coordinated multi-point system enables multiple base stations to transmit data to the user at the same time through the coordinated service of the cells in the coordinated multi-point system, and converts the inter-cell interference into a useful signal, which can significantly improve the receiving performance of the serving user, thereby improving Spectral efficiency at the cell edge. However, when there are multiple serving users in the cooperative cluster, the significant inter-user interference will cause a serious loss in the performance of the joint transmission system; moreover, when each user configures multiple receiving antennas and receives multiple data streams simultaneo...

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Problems solved by technology

[0003] When the channel state information (CSI) of all serving users is shared in the cooperative cluster, the global precoding method can be used to integrate the channel matrices from different base stations to a single user for overall precoding. This method has better system performance; however, its computational complexity is high, and often requires a central processing unit to process different channel information of users, and it is difficult to implement

In contrast, in the local precoding method, each base station obtains channel information between itself and different users, or adds certain shared CSI information between base stations, and the base station uses this information for precoding; this method avoids the centralized However, the performance of the local precoding method may be affected by the limited available space resources (such as the traditional regular block diagonalization (regular block diagonalization, RBD) Precoding and precoding based on signal-to-leakage-plus-noiseratio (Signal-to-leakage-plus-noiseratio, SLNR) maximization will be limited by system antenna configuration or insufficient utilization of space resources), resulting in a reduction in precoding performance

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