Method for enhancing the performance of downlink multi-user MIMO systems

A method for enhancing a performance of a downlink multi-user multiple-input multiple-output (MU-MIMO) system with insufficient multi-user interference suppression based on binary-valued user-specific frozen-bit patterns of polar codes, comprising steps of:

• determining a binary-valued user-specific frozen bit pattern sequence to be used in frozen bit locations for each user,
• performing a channel encoding on uncoded information bits of each user to generate coded bits via a polar encoder by using the binary-valued user-specific frozen bit pattern sequence to be used in the frozen bit locations of each user to improve the performance of the downlink MU-MIMO system,
• mapping of the coded bits of each user to symbols to generate a symbol sequence and performing a layer mapping for the symbol sequence,
• applying a multi-antenna precoding to obtain precoded symbols,
• performing a baseband-to-RF processing onto the precoded symbols,
• transmitting a baseband-to-RF processed signal of each user at same time-frequency resources using transmit antennas,
• receiving a transmitted signal at each user using receive antennas, wherein the transmitted signal is transmitted through respective downlink channels,
• applying an RF-to-baseband conversion to a received signal at each user,
• performing an equalization and a log-likelihood ratio (LLR) calculation on a baseband signal for detecting each user signal,
• decoding each user data using calculated LLRs and a polar decoder at each user by employing a corresponding binary-valued user-specific frozen bit pattern sequence used in the frozen bit locations to improve the performance of the ef-downlink MU-MIMO system.