The disclosed subject matter relates to employing modulation layer mapping to improve the performance of multiple-input and multiple-output (MIMO) communication systems. In one embodiment, a method comprises determining, by a device comprising a processor, codeword information in association with establishment of a wireless communication link with a network device of a wireless communication network, wherein the device and the network device are configured to communicate via the communication link using a MIMO communication scheme. The determining the codeword information comprises determining a code rate and determining a number of modulation indexes for the code rate based on signal-to-noise ratios respectively associated with channel layers included in the MIMO communication scheme. The method further comprises sending, by the device, the codeword information to the network device via a control channel of the wireless communication link.

This application provides a data sending method and apparatus. The method includes: A node generates a first modulation symbol corresponding to a first modulation scheme. The node quantizes the first modulation symbol to obtain a target symbol. The target symbol corresponds to one of a plurality of constellation points of a second modulation scheme. The node preprocesses the target symbol to obtain to-be-sent data. The preprocessing includes one or more of layer mapping, antenna port mapping, precoding, or transform precoding. The node maps the to-be-sent data to a physical resource, and sends the to-be-sent data by using the physical resource.

The present disclosure provides an apparatus and method for multi-level encoding of an input message sequence into a symbol sequence, for instance, based on polar coding. The input message comprises information bits. The apparatus is configured to divide the input message into a plurality of sub-messages, encode each of the sub-messages into a codeword, wherein a set of the sub-messages is encoded on the basis of the codewords obtained by encoding the sub-messages not in the set and a predefined function of the symbol sequence, and map the encoded sub-messages into corresponding symbols.

A method for constructing a codebook in a multiple-antenna wireless communication system and an apparatus therefor are disclosed. Specifically, constructing a codebook in a multiple-antenna wireless communication system comprises the steps of: receiving parameters for constructing a codebook from a base station; and constructing a codebook using the parameters for constructing the codebook, wherein the parameters for constructing the codebook may include a phase value () of a first code vector forming the codebook, a phase difference () between code vectors that are adjacent to one another within the codebook, and the number of bits () that is required when feeding back a code vector selected thin the codebook.

The channel estimation method for millimeter-wave communication includes virtual multipath acquisition and sparse reconstruction. In the virtual multipath acquisition stage, instead of searching the real multipath components (MPCs), the virtual representation of the real MPCs is derived, and the hierarchical search is utilized to acquire the virtual MPCs based on a normal limited-resolution codebook. In the sparse reconstruction stage, the real MPCs are reconstructed from the virtual MPCs acquired in the virtual multipath acquisition stage. An enhanced sub-array scheme is used to design a hierarchical codebook under a strict constant-modulus constraint. The designed codebook can be used for both analog and hybrid beamforming/combining devices. The training overhead of channel estimation and the complexity of the search are significantly reduced, and the size of the dictionary matrix is greatly reduced by exploiting the results of the virtual multipath acquisition.

Embodiments provide methods for wireless Multi-User Multiple Input Multiple Output communications comprising creating a Demodulation reference signal (DM-RS); the DM-RS being associated with at least one of or more than one antenna port, a scrambling identity, a number of layers or an orthogonal code associated with the reference signal.

A method of data transmission includes determining the number of layers, generating mapping symbols by mapping modulation symbols for a first codeword and modulation symbols for a second codeword to each layer, and transmitting the mapping symbols through a plurality of antennas. At least one of the first codeword and the second codeword is mapped to at least 3 layers and the number of layers is larger than 3.

Various aspects of the disclosure relate to a codebook design that defines phase rotation on one or more layers of a codebook. This codebook may be used, for example, for sparse code multiple access (SCMA) encoding. One feature pertains to a method of communication that includes receiving at least one input signal, and mapping each of the at least one input signal to a corresponding layer of a codebook, where the codebook defines phase rotation between the layers. The method may further include generating a coded signal for each of the at least one input signal on each corresponding layer based on the codebook, and generating an output signal based on each generated coded signal.

A method for transmitting and receiving a codebook subset restriction bitmap is provided. The Codebook Subset Restriction (CSR) bitmap transmission method of an evolved Node B (eNB) in transmission mode 9 for communication with 8 antenna ports includes generating a CSR bitmap including bits corresponding to restricted precoding matrix indicators and rank indicators that are not allowed for reporting and transmitting the CSR bitmap to a User Equipment (UE). The CSR bitmap comprises 53 bits corresponding to a first codebook and 56 bits corresponding to a second codebook, the 53 bits corresponding to a first codebook comprise 16, 16, 4, 4, 4, 4, and 1 bits for layers 1, 2, 3, 4, 5, 6, 7, and 8, respectively, and the 56 bits corresponding to a second codebook comprise 16, 16, 16 and 8 bits for layers 1, 2, 3, and 4, respectively.

A method of data transmission includes determining the number of layers, generating mapping symbols by mapping modulation symbols for a first codeword and modulation symbols for a second codeword to each layer, and transmitting the mapping symbols through a plurality of antennas. At least one of the first codeword and the second codeword is mapped to at least 3 layers and the number of layers is larger than 3.