Abstract: A method and a device for feeding back and receiving downlink channel information are disclosed, whereby spectrum utilization ratio of downlink channel information feedback is enhanced. According to the present invention, a wireless terminal superposes an uplink user information sequence with spectrum-spread downlink channel information before transmission. A network side de-spreads a received signal before estimating the downlink channel information, and then detects the user information sequence after subtracting the estimated downlink channel information from the received signal. An orthogonal code can be employed to spread the spectrum of the downlink channel information. The wireless terminal and base station use a plurality of antennas for transmission and reception.

Abstract: A method, an apparatus, and a system for forming Time Division Duplex (TDD) Multi-Input Multi-Output (MIMO) downlink beams are disclosed herein. The method includes: generating a transmitting beam of a first data stream according to a Maximum Rate Transmission (MRT) criterion; and generating transmitting beams of other data streams except the first data stream, wherein the transmitting beams of other data streams are confined in a null space of the transmitting beam of the first data stream. Through the embodiments of the present invention, the Base Station obtains precise Partial Channel State Information by using only reciprocity without requiring feedback information, and thus the calculation is simplified and the rate of data streams is improved.

Abstract: A method, a system, and an apparatus for improving throughput performance of an SDMA system are disclosed herein. The method includes BTS receiving feedback information sent by a UE, where the feedback information comprises an ID of a preferred beam of the UE in a pre-coding codebook, information related to a channel vector modulus value, and information about phase difference between a channel vector and the preferred beam of the UE, and the BTS using a set estimation algorithm to estimate sum throughputs supported by a current SDMA system in each sending mode according to the received feedback information and information about space correlation between multiple antennas of the BTS, selecting a maximum sum throughput among the estimated sum throughputs, and using the sending mode corresponding to this sum throughput to send data. The method, system, and apparatus provided herein improve transmitting performance of the SDMA system.

Abstract: In a method for forming TDD MIMO downlink beams, a BS receives an index of a codebook element from a mobile terminal. The codebook element refers to a codebook element whose correlation value has a greatest modulus value among correlation values that are calculated by the mobile terminal and are about correlation between the codebook element and a channel corresponding to a non-transmitting antenna of the mobile terminal. The BS calculates a channel vector corresponding to the non-transmitting antenna of the mobile terminal. The BS calculates channel vectors of the transmitting antennas of the mobile terminal, and performs SVD to determine a best transmitting precoding matrix.

Abstract: A multi-user multi-input multi-output (MIMO) method for transmitting signal with a includes: performing a Tomlinson-Harashima pre-coding (THP) on raw data; decomposing a channel matrix to a product of a block triangular matrix and a unitary matrix, and generating a signal to be transmitted by performing a forward filtering on the THP coded data by using the unitary matrix. A multi-user MIMO apparatus for transmitting signal includes an interference pre-eliminating unit, a modulo unit, a forward filtering unit, and a channel matrix decomposing unit. A multi-user MIMO communication system is further provided.

Abstract: A method, a system, and an apparatus for improving throughput performance of an SDMA system are disclosed herein. The method includes BTS receiving feedback information sent by a UE, where the feedback information comprises an ID of a preferred beam of the UE in a pre-coding codebook, information related to a channel vector modulus value, and information about phase difference between a channel vector and the preferred beam of the UE, and the BTS using a set estimation algorithm to estimate sum throughputs supported by a current SDMA system in each sending mode according to the received feedback information and information about space correlation between multiple antennas of the BTS, selecting a maximum sum throughput among the estimated sum throughputs, and using the sending mode corresponding to this sum throughput to send data. The method, system, and apparatus provided herein improve transmitting performance of the SDMA system.

Abstract: In a method for forming TDD MIMO downlink beams, a BS receives an index of a codebook element from a mobile terminal. The codebook element refers to a codebook element whose correlation value has a greatest modulus value among correlation values that are calculated by the mobile terminal and are about correlation between the codebook element and a channel corresponding to a non-transmitting antenna of the mobile terminal. The BS calculates a channel vector corresponding to the non-transmitting antenna of the mobile terminal. The BS calculates channel vectors of the transmitting antennas of the mobile terminal, and performs SVD to determine a best transmitting precoding matrix.

Abstract: A method, an apparatus, and a system for forming Time Division Duplex (TDD) Multi-Input Multi-Output (MIMO) downlink beams are disclosed herein. The method includes: generating a transmitting beam of a first data stream according to a Maximum Rate Transmission (MRT) criterion; and generating transmitting beams of other data streams except the first data stream, wherein the transmitting beams of other data streams are confined in a null space of the transmitting beam of the first data stream. Through the embodiments of the present invention, the Base Station obtains precise Partial Channel State Information by using only reciprocity without requiring feedback information, and thus the calculation is simplified and the rate of data streams is improved.

Abstract: A multi-user multi-input multi-output (MIMO) method for transmitting signal with a includes: performing a Tomlinson-Harashima pre-coding (THP) on raw data; decomposing a channel matrix to a product of a block triangular matrix and a unitary matrix, and generating a signal to be transmitted by performing a forward filtering on the THP coded data by using the unitary matrix. A multi-user MIMO apparatus for transmitting signal includes an interference pre-eliminating unit, a modulo unit, a forward filtering unit, and a channel matrix decomposing unit. A multi-user MIMO communication system is further provided.

Abstract: A method for scheduling an SDMA codebook includes: selecting, by a user, a most matching precoding matrix and a minimally interfering cluster in the SDMA codebook according to Channel State Information, CSI, of the user; calculating a data transmission rate supportable when the user undergoes interference caused by the minimally interfering cluster; and feeding back an index of the most matching precoding matrix, an index of the minimally interfering cluster, and the data transmission rate to a base station. An apparatus and system for scheduling an SDMA codebook is also provided.

Abstract: A method and a device for feeding back and receiving downlink channel information are disclosed, whereby spectrum utilization ratio of downlink channel information feedback is enhanced. According to the present invention, a wireless terminal superposes an uplink user information sequence with spectrum-spread downlink channel information before transmission. A network side de-spreads a received signal before estimating the downlink channel information, and then detects the user information sequence after subtracting the estimated downlink channel information from the received signal. An orthogonal code can be employed to spread the spectrum of the downlink channel information. The wireless terminal and base station use a plurality of antennas for transmission and reception.