An uplink multiple access method based on the user-specific frozen bit patterns of polar codes assigned to users and relevant transmitter-receiver embodiments. The method includes encoding the information bits with a polar encoder by using the binary-valued, user-specific frozen bit patterns in frozen bit locations during encoding operation. The method further includes mapping of coded bits with symbols to be transmitted and baseband-to-RF processing performed on the symbol sequence. The generated signals of each user are transmitted by using the same time-frequency resources. The method further includes to receive the superposed signal of multiple users transmitted by means of relevant uplink radio channels. The method further includes an RF-to-baseband conversion on the received signal and detecting and decoding each user data by using an interference cancellation multiuser detector and a polar decoder that uses binary-valued pattern sequences assigned to the users in the frozen bit locations.

Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, said transmission channel being represented by an upper triangular matrix, wherein the decoder comprises: a processing unit (309) configured to determine a set of division parameters depending on at least one division metric derived from components of said upper triangular matrix; a decoding unit (311) configured to divide said upper triangular matrix into two or more sub-matrices using said set of division parameters in accordance with a division of said vector of information symbols into two or more sub-vectors, and to determine at least one estimate of each sub-vector of information symbols by applying a symbol estimation algorithm,
wherein the decoder is configured to determine at least one estimate of said vector of information symbols from the estimates of said sub-vectors of information symbols.

A method and apparatus for implementing spatial processing with unequal modulation and coding schemes (MCSs) or stream-dependent MCSs are disclosed. Input data may be parsed into a plurality of data streams, and spatial processing is performed on the data streams to generate a plurality of spatial streams. An MCS for each data stream is selected independently. The spatial streams are transmitted via multiple transmit antennas. At least one of the techniques of space time block coding (STBC), space frequency block coding (SFBC), quasi-orthogonal Alamouti coding, time reversed space time block coding, linear spatial processing and cyclic delay diversity (CDD) may be performed on the data/spatial streams. An antennal mapping matrix may then be applied to the spatial streams. The spatial streams are transmitted via multiple transmit antennas. The MCS for each data stream may be determined based on a signal-to-noise ratio of each spatial stream associated with the data stream.

A transmitter broadcasts a signal having a different code characteristic for each of several directions. A receiver receives the broadcast signal from one of the directions and generates an expected signal for that direction based on the code characteristic for that direction. The receiver detects the broadcast signal from the direction based on the expected signal for that direction.

An optical transmission system includes an optical transmission apparatus and an optical reception apparatus. The optical transmission apparatus includes a conversion unit that converts multiple binary data sequences into data in a predetermined signal format; a coding unit that generates multiple pieces of coded data by performing predetermined coding on each of the multiple pieces of converted data; an optical signal generation unit that generates multiple optical signals by converting the multiple pieces of coded data into optical signals; and a mode multiplexer that converts the multiple optical signals into different modes, generates a mode-division multiplexed optical signal by mode-division multiplexing the optical signals, and transmits the generated mode-division multiplexed optical signal to the optical reception apparatus. The optical reception apparatus includes a mode demultiplexer that demultiplexes the mode-division multiplexed optical signal transmitted from the optical transmission apparatus into light in different modes; a photoelectric conversion unit that converts the light in the multiple different modes into electrical signals; an analog/digital conversion unit that converts the multiple electrical signals into coded data; and an MIMO equalization processing unit that performs MIMO equalization processing on the converted coded data.

A method that may include receiving, by multiple antennas of a receiver, received signals that are received with diversity and represent transmitted signals; and processing, by at least one processor of the receiver, the received signals to provide processed signals that are indicative of the transmitted signals; wherein the processing comprises applying a dimension-reducing process. The dimension-reducing process may be channel independent.

A method for determining a number of symbols in a data field of a physical layer (PHY) protocol data unit (PPDU) is described. The method includes determining, by a wireless transmitting device, whether aggregation is to be applied to the PPDU; determining, by the wireless transmitting device, whether a PSDU length indication of the data field for the PPDU is greater than zero; selecting, by the wireless transmitting device, a first value in response to determining that (1) aggregation is not to be applied to the PPDU and (2) the PSDU length indication for the PPDU is greater than zero; and calculating, by the wireless transmitting device, the number of symbols in the data field of the PPDU based on the first value, wherein the first value is the PSDU length indication.

A method for determining a number of symbols in a data field of a physical layer (PHY) protocol data unit (PPDU) is described. The method includes determining, by a wireless transmitting device, whether an aggregation subfield of a signal field of the PPDU is to be set to 1 and responsive to determining that the aggregation subfield of the signal field of the PPDU is not to be set to 1, calculating, by the wireless transmitting device, the number of symbols in the data field of the PPDU based on a PHY service data unit (PSDU) length value, wherein the PSDU length value is provided in a transmission vector (TXVECTOR) and the TXVECTOR also includes an aggregated media access control (MAC) protocol data unit pre-end-of-frame padding (APEP) length value of the PPDU.

First user equipment (UE) exchanges at least a portion of data to be transmitted to a communication network with a second UE on a side channel. The UEs then send the data to the network at increased transmission power by using transmit antennas of both the first and second UEs, instead of just those of the first UE. In some cases, the second UE may transmit a variation of the data sent by the first UE to perform transmit diversity and improve signal-to-noise ratio. To avoid unintended beamforming of the transmissions, the network may mix signals (e.g., having a same symbol) received at the same time period but at different sub-carriers, or mix the signals received at different time periods but at the same sub-carrier. The network may notify the UEs of a phase correction value based on the signals, and the UEs may adjust using the phase correction value.

A transmission apparatus includes a transmission signal generator which, in operation, generates a transmission signal having an aggregate physical layer protocol data unit (PPDU) that includes a legacy preamble, a legacy header, a non-legacy preamble, a plurality of non-legacy headers and a plurality of data fields; and a transmitter which, in operation, transmits the generated transmission signal, wherein the legacy preamble, the legacy header and the plurality of non-legacy headers are transmitted using a standard bandwidth, the non-legacy preamble and the plurality of data fields are transmitted using a variable bandwidth that is larger than the standard bandwidth and wherein a plurality of sets of each of the plurality of non-legacy headers and each of the plurality of data fields are transmitted sequentially in a time domain.