In the present invention, disclosed is a method for uplink multi-user transmission in a wireless communication system and an apparatus therefor. Specifically, a method for performing, by a station (STA), uplink (UL) multi-user (MU) transmission in a wireless communication system comprises the steps of: receiving, from an access point (AP), a trigger frame including information for UL MU transmission; and transmitting an UL MU PPDU on the basis of the information for UL MU transmission, wherein the trigger frame is a medium access control (MAC) frame, a MAC header of the trigger frame includes a type field and a subtype field, and the type of the trigger frame may be indicated by the type field and the subtype field.

A first radio signal is received that was transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna. The first radio signal is converted to a first orthogonal frequency division multiplexing (OFDM) frame signal, and the second radio signal is converted to a second OFDM frame signal. The first OFDM frame signal includes a grid of multiple frequency subcarriers and time periods, each time period with the frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes first OFDM symbols. A first OFDM symbol is carried on frequency subcarriers during a time period, and the first OFDM frame includes first reference OFDM symbols located at corresponding time-frequency resource elements in the grid. Each resource element is defined by a one of the frequency subcarriers and one of the time periods. The second OFDM frame signal is similar and includes second reference OFDM symbols sharing the same grid of frequency subcarriers and time periods as the first OFDM frame. But the second reference OFDM symbols are located at corresponding time-frequency resource elements in the grid different than the corresponding time-frequency resource elements to which the first reference OFDM signals are located their respective OFDM frame signals. The first and second reference OFDM symbols are used to demodulate the first and second OFDM frame signals.

Embodiments of the present disclosure provide a method and system for implementing multi-user multiple-input multiple-output (MU-MIMO). The method includes: connecting two MU-MIMO-supported access points to form a virtual access point stack; setting a primary access point and a secondary access point in the virtual access point stack; performing access point configuration on the primary access point, and synchronizing the configuration of the primary access point to the secondary access point; and scheduling all antennas of the virtual access point stack by the primary access point. According to the embodiments of the present disclosure, wireless capacity is improved without consuming extra wireless spectrum resources.

Disclosed are one or more preferred geometric configurations for a device communicably coupled to a power transmission line and capable of launching transverse electromagnetic waves onto the transmission line. The waves propagate data received from a data source and may include a reflector and a coupler adjacent to each other through a transverse magnetic wave that propagates longitudinally along the surface of the transmission line.

A method for transmitting a reference signal in a multi-antenna system is provided. The method includes: selecting at least one orthogonal frequency division multiplexing (OFDM) symbol in a subframe containing a plurality of OFDM symbols; allocating a channel quality indication reference signal (CQI RS) capable of measuring a channel state for each of a plurality of antennas to the selected at least one OFDM symbol; and transmitting the CQI RS, wherein the CQI RS is allocated to an OFDM symbol which does not overlap with an OFDM symbol to which a common reference signal to be transmitted to all user equipments in a cell or a dedicated reference signal to be transmitted to a specific user equipment in the cell is allocated.

An apparatus comprises: a first plurality of first radio frequency chains; a second plurality of second radio frequency chains, the first radio frequency chains being configured to produce wider side-band emissions than the second radio frequency chains; at least one antenna array comprising antenna elements, each of a first plurality of the antenna elements being coupled with a corresponding one of the first plurality of first radio frequency chains, the first plurality of first radio frequency chains being configured to cause transmissions predominately in a first band within a channel, each of a second plurality of the antenna elements being coupled with a corresponding one of the second plurality of second radio frequency chains, the second plurality of second radio frequency chains being configured to cause transmissions predominately in at least one second band within the channel.

The present disclosure relates to a physical downlink control channel (PDCCH) sending method. The method may be applicable to a base station that includes at least two transmitters. The method includes: sending PDCCHs to a terminal through a plurality of transmitters, where Demodulation Reference Signal (DMRS) sequences for the PDCCHs sent by the plurality of transmitters are different.

Antenna arrays to be used in MIMO apparatuses are disclosed. Such an antenna array may include a plurality of array elements, wherein every second element in a first direction is a digital pre-distortion-less linear element, and every second element in the first direction is a non-linear element. In the antenna array, spacing between adjacent elements in the first direction is less than a half of a free space wavelength. A non-linear precoding is applied to transmissions from the antenna array, the non-linear precoding converting out-of-band emissions of the transmissions into reactive power in the near-field around the antenna array while ensuring that in-band signals generated by the elements remain unaffected.

An airborne RF-head platform system and method. Here, much of the computational burden of transmitting and receiving wireless RF waveforms is shifted from the airborne platform to a ground baseband unit (BBU). The airborne platform, which will often be a high altitude balloon or drone type platform, generally comprises one or more remote radio heads, configured with antennas, A/D and D/A converters, frequency converters, RF amplifiers, and the like. The airborne platform communicates with the ground baseband units either directly via a laser communications link, or indirectly through another airborne relay platform. The airborne RF-head communicates via various wireless protocols to various user equipment such as smartphones by using the BBU and the laser communications link to precisely control the function of the airborne A/D and D/A converters and antennas. This system reduces the power needs, weight, and cost of the airborne platform, and also improves operational flexibility.

An information handling system operating a reconfigurable antenna training control system may comprise a configurable antenna system in one of a plurality of available configurations transceiving a radio frequency signal, and a radio frequency system measuring performance metrics for the signal transceived according to each available configuration over a training time period preset based on historical performance and stability of each available configuration. An antenna front end system may execute instructions of the reconfigurable antenna training control system to determine a weighted performance metric based on the measured performance metrics and on historical performance metrics for each candidate configuration, to compare the weighted performance metrics for each configuration, and to identify one of the configurations having a highest weighted performance metric as an optimal configuration. The configurable antenna may then establish a wireless link using the optimal configuration.