A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.

Precoding coefficients can be compressed based on user equipment signal interference to noise ratio or path loss in front haul cloud radio access network systems. For example, a baseband unit can compute a precoder matrix from an estimated channel associated with an uplink signal. Once the baseband unit computes the channel, it can determine the coefficients for the linear combination of the basis vectors, which are known at the baseband unit and the radio unit as well. The baseband unit can estimate the path loss and the signal interference to noise ratio and determine the basis vectors. The baseband unit can then compress the coefficients and transmit the coefficients to the radio unit. When the radio unit receives the compressed coefficients, the radio unit can reconstruct the precoder matrix and apply to reference signals and data traffic channels.

A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having 1-layer, 2-layer, 3-layer, and 4-layer codebooks for 4 transmit antenna (4TX) transmission, each codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each of the 1-layer and 2-layer codebooks comprises a first codebook and a second codebook, and wherein each precoding matrix in the first codebook comprises a first index and a second index. Other apparatuses, systems, and methods also are disclosed.

A method performed by a base station of enabling a User Equipment (UE) to determine a precoder codebook in a wireless communication system is provided. The base station transmits, to the UE, information regarding precoder parameters enabling the UE to determine the precoder codebook. The precoder parameters are associated with a plurality of antenna ports of the base station. The precoder parameters relate to a first dimension and a second dimension of the precoder codebook. The plurality of antenna ports comprises a number of antenna ports that is a function of a number of antenna ports in the first dimension, and a number of antenna ports in the second dimension.

Precoding coefficients can be compressed based on user equipment signal interference to noise ratio or path loss in front haul cloud radio access network systems. For example, a baseband unit can compute a precoder matrix from an estimated channel associated with an uplink signal. Once the baseband unit computes the channel, it can determine the coefficients for the linear combination of the basis vectors, which are known at the baseband unit and the radio unit as well. The baseband unit can estimate the path loss and the signal interference to noise ratio and determine the basis vectors. The baseband unit can then compress the coefficients and transmit the coefficients to the radio unit. When the radio unit receives the compressed coefficients, the radio unit can reconstruct the precoder matrix and apply to reference signals and data traffic channels.

Precoding coefficients can be compressed based on user equipment signal interference to noise ratio or path loss in front haul cloud radio access network systems. For example, a baseband unit can compute a precoder matrix from an estimated channel associated with an uplink signal. Once the baseband unit computes the channel, it can determine the coefficients for the linear combination of the basis vectors, which are known at the baseband unit and the radio unit as well. The baseband unit can estimate the path loss and the signal interference to noise ratio and determine the basis vectors. The baseband unit can then compress the coefficients and transmit the coefficients to the radio unit. When the radio unit receives the compressed coefficients, the radio unit can reconstruct the precoder matrix and apply to reference signals and data traffic channels.

A high-dimensional signal transmission method is provided. The method generates M M-dimensional first signals on the basis of M original signals and generates M M-dimensional second signals on the basis of a precoding signal and of the first signals, and finally, a transmitter sums all of the second signals and then transmits by utilizing M subchannels. As such, each subchannel carries information of the M original signals; hence, when any subchannel experiences deep fading, the deep fading is shared jointly by M signals, thus preventing the deep fading from causing a particularly severe impact on any signal. Moreover, all of the original signals can be recovered by utilizing the signals on the other subchannels, thus increasing the systematic resistance against subchannel deep fading. Meanwhile, the system implements the parallel transmission of the M original signals, thus ensuring the throughput of a communication system.

A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation sheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

A communications method, apparatus, and system are provided. The method includes: receiving, by a terminal, configuration information from a radio access network (RAN) node, where the configuration information is used to configure precision of a multi-stage codebook, and codebook precision at different stages is different; and performing, by the terminal, reporting for codebook information based on the configuration information, where information about an M.sup.th-stage codebook limits a range of an (M+1).sup.th-stage codebook, and M is a positive integer and is less than a codebook stage quantity. The RAN node configures the precision of the multi-stage codebook for the terminal to enable the codebook precision at all the stages to be different, to obtain a more flexible codebook. In addition, information about a previous-stage codebook limits a range of a current-stage codebook, so that the terminal can perform codebook measurement and reporting within a specific range, thereby reducing reporting overheads.