As for a communication system having a plurality of transmission antennas, different data is respectively transmitted to a plurality of different users simultaneously at the same frequency, so that an interference occurs among a plurality of user data. Therefore, it has become a technical problem to be solved in a multi-user communication system to eliminate the interference among multiple users. The multi-user communication system includes a multi-user multiple-input single-output (MISO) communication system and a multi-user MIMO communication system.
In the multi-user MISO communication system, Tomlinson-Harashima pre-coding (THP) is adopted. As a simple and feasible non-linear pre-coding technique, the THP has been widely applied.
The THP technique based on the multi-user MISO communication system can also be applied in the multi-user MIMO communication system. Particularly, the THP is performed by means of considering a plurality of receiving antennas from the same user as different users of a single antenna. Here, in the multi-user MIMO system, cooperative processing among the receiving antennas of the users cannot be adopted. Therefore, in the multi-user MIMO system, optimality of the THP cannot be guaranteed.
In the multi-user MIMO communication system, due to the interferences among the multiple users and the interferences among a plurality of data streams of the user, if the interferences among the users cannot be eliminated, the system performance is seriously affected.