A first device transmits to a second device a first data unit which indicates a maximum number of long training field (LTF) symbols that the first device transmits and receives for a multiple input multiple output communication. The first device receives, from the second device, a second data unit which comprises a plurality of LTF symbols up to the maximum number of LTF symbols the first device receives indicated by the first data unit. A channel estimation is performed based on the plurality of LTF symbols of the second data unit up to the maximum number of LTF symbols indicated by the first data unit to recover information in one or more fields of the second data unit. For the case when the second data unit is a trigger frame, the first device generates the third data unit with a plurality of LTF symbols up to the maximum number of LTF symbols the first device transmits indicated by the first data unit and transmits the third data unit.

Systems and methods for OFDM channelization are provided that allow for the coexistence of sub-band channels and diversity channels. Methods of defining diversity sub-channels and sub-band sub-channels are provided and systematic channel definition and labeling schemes are provided.

In a transmission method according to one aspect of the present disclosure, a encoder performs error correction coding on an information bit string to generate a code word. A mapper modulates a first bit string in which the number of bits is the predetermined integral multiple of (X+Y) in the code word using a first scheme, the first scheme being a set of a modulation scheme in which an X-bit bit string is mapped to generate a first complex signal and a modulation scheme in which a Y-bit bit string is mapped to generate a second complex signal, and modulates a second bit string in which the first bit string is removed from the code word using a second scheme different from the first scheme.

Methods and systems that can enable antenna selection (AS) and data bits in transmitted spatially modulated (SM) streams to be detected at a receiver using different detection methods. In example embodiments, encoding for an AS stream is done separately at a transmitter than encoding for data streams, enabling a receiver to use one type of detection for AS bits and a reduced complexity type of MIMO detection for the data bits.

The disclosure provides methods and apparatus which relate to control channel decoding in a wireless communications network. In one aspect, there is provided a method in a wireless device for a wireless communications network. The method includes receiving a first set of coded control symbols on a physical control channel in a first time slot, receiving a second set of coded control symbols on the physical control channel in a second time slot subsequent to the first time slot, and attempting to decode a control message based on the first set of coded control symbols and the second set of coded control symbols using one or more soft-combining techniques.

A disclosed transmitter for wireless communication includes multiple transmitting antennas, a symbol mapper for mapping an input block including multiple binary bits and representing information to be transmitted to a symbol representing an ordered plurality of complex numbers, a space-time encoder for applying an encoding operator to the symbol to produce a vectorized space-time codeword defining electrical signals to be transmitted by the transmitter, the encoding operator being dependent on a set of predefined stabilizer generators, and circuitry to collectively transmit, by the antennas to multiple receiving antennas of a receiver over a wireless transmission channel, the electrical signals defined by the vectorized space-time codeword. The receiver includes a space-time decoder for recovering the symbol from the electrical signals transmitted by the transmitter using a decoding operation that is based on maximum likelihood inference, and a symbol de-mapper for recovering the input block from the symbol.

Systems and methods are provided for introducing time diversity in a transmitter. The systems and methods may include receiving, at the transmitter, a request from a receiver to retransmit data. The systems and methods may further include receiving an input of data corresponding to the data requested for retransmission at a first transmitter block. The systems and methods may further include operating on the signals using the first transmitter block in at least one of a first mode and a second mode, such that an output of signals from the first transmitter block is dependent on a time-varying function and corresponds to the data requested by the receiver for retransmission.

The present application discloses a method for operating a wireless communication system. The method includes receiving a series of input data bits in a current timeslot by a transmitter and encoding the input data bits with a cross-Gray coding scheme to obtain coded information bits. Additionally, the method includes mapping the coded information bits to obtain respective multiple transmission symbols X.sub.t for the current timeslot in a constellation diagram. Furthermore, the method includes converting the multiple transmission symbols X.sub.t to generate a space-time matrix S.sub.t of the current timeslot by incorporating spatial bits associated with orders of respective transmitting antennas based on a space-time matrix S.sub.t-1 of a previous timeslot. Moreover, the method includes transmitting a respective one of elements in the space-time matrix S.sub.t using a respective one transmitting antenna activated in the transmitter.

The present invention provides a WLAN system resource indication method and apparatus. The method includes: generating, by an access point, a frame that carries resource indication information; and sending, to multiple stations, the frame that carries the resource indication information. The resource indication information includes multiple pieces of sub resource indication information. Correspondingly, each piece of the sub resource indication information uniquely corresponds to one of the multiple stations. Therefore, a station side does not need read the entire resource indication information, so as to reduce resource overheads and improve efficiency.

Spatial spreading is performed in a multi-antenna system to randomize an “effective” channel observed by a receiving entity for each transmitted data symbol block. For a MIMO system, at a transmitting entity, data is processed (e.g., encoded, interleaved, and modulated) to obtain N.sub.D data symbol blocks to be transmitted in N.sub.M transmission spans, where N.sub.D≥1 and N.sub.M>1. The N.sub.D blocks are partitioned into N.sub.M data symbol subblocks, one subblock for each transmission span. A steering matrix is selected (e.g., in a deterministic or pseudo-random manner from among a set of L steering matrices, where L>1) for each subblock. Each data symbol subblock is spatially processed with the steering matrix selected for that subblock to obtain transmit symbols, which are further processed and transmitted via N.sub.T transmit antennas in one transmission span. The N.sub.D data symbol blocks are thus spatially processed with N.sub.M steering matrices and observe an ensemble of channels.