Methods are described allowing a vector signaling code to encode multi-level data without the significant alphabet size increase known to cause symbol dynamic range compression and thus increased noise susceptibility. By intentionally restricting the number of codewords used, good pin efficiency may be maintained along with improved system signal-to-noise ratio.

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a configuration signal indicating a codebook construction configuration for constructing a codebook of sequences for conveying a first type of uplink payload in a resource block that is orthogonal to a second type of uplink payload transmitted from a second UE in the resource block. The UE may construct the codebook of sequences for the first type of uplink payload according to the codebook construction configuration. The UE may generate the first type of uplink payload for transmission using a first sequence from the codebook of sequences. The UE may transmit the first type of uplink payload in the resource block, wherein the first type of uplink payload is multiplexed in the resource block with the second type of uplink payload from the second UE.

The present disclosure relates to methods and devices for wireless communication including an apparatus, e.g., a UE and/or base station. The apparatus can determine a first orthogonal matrix and a second orthogonal matrix, the first orthogonal matrix including a size of M×N1 with M×N1 rows and M×N1 columns, the second orthogonal matrix including a size of M×N2 with M×N2 rows and M×N2 columns. The apparatus can also determine a first codebook based on the first orthogonal matrix and a second codebook based on the second orthogonal matrix, the first codebook and the second codebook including a plurality of codepoints. Also, the apparatus can transmit a first signal and a second signal, the first signal including a first codepoint of the plurality of codepoints in the first codebook, the second signal including a second codepoint of the plurality of codepoints in the second codebook.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit an uplink payload in a wireless communications system. The UE may identify a set of sequences configured for conveying a payload including a set of bits, where each sequence of the set of sequences is orthogonal to each other sequence of the set of sequences. The UE may select a first sequence from the set of sequences based on a mapping between the set of sequences and payload values corresponding to the set of bits. The UE may transmit the payload including the set of bits using the first sequence.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit an uplink payload in a wireless communications system. The UE may identify a set of sequences configured for conveying a payload including a set of bits, where each sequence of the set of sequences is orthogonal to each other sequence of the set of sequences. The UE may select a first sequence from the set of sequences based on a mapping between the set of sequences and payload values corresponding to the set of bits. The UE may transmit the payload including the set of bits using the first sequence.

Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) or a base station, or both, may generate a set of orthogonal sequences that the UE may use to convey a payload of a number of bits based on a product of an orthogonal matrix and a cell-specific sequence. The UE or the base station, or both, may select a subset of the set of orthogonal sequences based on the number of bits in the payload, and the UE may construct a codebook including the subset of orthogonal sequences. The UE may select an orthogonal sequence from the constructed codebook based on the bits in the payload. The UE may transmit the payload including the number of bits to the base station using the selected orthogonal sequence.

Disclosed is a channel-dependent multi-carrier code division multiple access (MC-CDMA) technique with adaptive spreading codes. Adaptive spreading codes are used for each subcarrier per user which increase the security level of conventional MC-CDMA. Two different map designs are proposed: fixed and adaptive interval maps. These maps are shared among all nodes and gives information about the spreading code sequences for corresponding channel gains.

Disclosed is a channel-dependent multi-carrier code division multiple access (MC-CDMA) technique with adaptive spreading codes. Adaptive spreading codes are used for each subcarrier per user which increase the security level of conventional MC-CDMA. Two different map designs are proposed: fixed and adaptive interval maps. These maps are shared among all nodes and gives information about the spreading code sequences for corresponding channel gains.