A method for reducing channel sounding overhead in a MU-MIMO WLAN system, and apparatus for performing the method are disclosed. The method includes transmitting a sparse set of pilot symbols in a pseudorandom distribution across a plurality of subcarriers, from a plurality of antennas to one or more client devices on a plurality of spatial streams; receiving a sparse set of channel estimates in the frequency and spatial domains, from the one or more client devices as beamforming feedback based on the sparse set of pilot symbols; and recovering the channel in a compressed sensing framework.

A method for reducing channel sounding overhead in a MU-MIMO WLAN system, and apparatus for performing the method are disclosed. The method includes transmitting a sparse set of pilot symbols in a pseudorandom distribution across a plurality of subcarriers, from a plurality of antennas to one or more client devices on a plurality of spatial streams; receiving a sparse set of channel estimates in the frequency and spatial domains, from the one or more client devices as beamforming feedback based on the sparse set of pilot symbols; and recovering the channel in a compressed sensing framework.

Disclosed is a transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

The disclosed systems, structures, and methods are directed to a multiple-input multiple-output (MIMO) receiver. The MIMO receiver includes at least two receiver antenna elements to receive radiated MIMO signal beams containing superposed order modes and to generate antenna element output signals based on the received MIMO signal beams. The receiver antenna elements are spatially separated by a distance. A variable ratio combining unit operates to switch between the antenna output signals based on a high-rate periodic waveform that emulates unidirectional movement by the antenna elements to produce a pseudo-Doppler frequency shift. The variable ratio combining unit further modulates the antenna output signals based on the periodic waveform to impart a fractional pseudo-Doppler shift to each MIMO mode and combines the modulated antenna element output signals in accordance with the fractional pseudo-Doppler shift to facilitate separation of the MIMO modes.

A network controller is configured to receive a data packet from a core network for routing to a device in a wireless network. The controller may then select an antenna set from a plurality of antenna sets that are distributed across different base stations operable to transmit data packets to the destination device. The antenna set may be selected from the plurality of antenna sets based on a distribution pattern. For example, the distribution pattern may be a pseudo-randomly generated distribution pattern. The controller may then route the at least one data packet to the base station which the selected antenna set is implemented for transmission to the device. The antenna sets may be implemented on one base station, or implemented so that the antennas of an antenna set are distributed across multiple base stations. The antenna sets may also be configured to be of any number of antennas.

The disclosed systems, structures, and methods are directed to a multiple-input multiple-output (MIMO) receiver. The MIMO receiver includes at least two receiver antenna elements to receive radiated MIMO signal beams containing superposed order modes and to generate antenna element output signals based on the received MIMO signal beams. The receiver antenna elements are spatially separated by a distance. A variable ratio combining unit operates to switch between the antenna output signals based on a high-rate periodic waveform that emulates unidirectional movement by the antenna elements to produce a pseudo-Doppler frequency shift. The variable ratio combining unit further modulates the antenna output signals based on the periodic waveform to impart a fractional pseudo-Doppler shift to each MIMO mode and combines the modulated antenna element output signals in accordance with the fractional pseudo-Doppler shift to facilitate separation of the MIMO modes.

The present invention provides a method of transmitting broadcast signals. The method includes, formatting, by an input formatting block, input streams into plural PLPs (Physical Layer Pipes); encoding, by an encoder, data in the plural PLPs; processing, by a framing and interleaving block, the encoded data in the plural PLPs to output at least one signal frame; and waveform modulating, by a waveform generation block, data in the at least one signal frame and transmitting, by the waveform generation block, broadcast signals having the waveform modulated data.

Disclosed is a transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.

A communication system, a coordinator and a controlling method thereof are provided. The embodiment of the communication system is used for one or more user equipments. The controlling method includes the following steps. A measurement of a plurality of antenna configurations corresponding to the one or more user equipments is controlled to obtain a plurality of performance values. The performance values of the antenna configurations corresponding to the one or more user equipments are recorded. An embodiment of the communication system includes a plurality of Remote Radio Heads, each of which is electronically connected to a plurality of antennas.

A communication system is provided comprising a transmitter coupled to a switch, which is further coupled to at least two antennas for switching the transmit signal to one of the antennas, with no feedback. The communication system further comprises at least one receiver for receiving the transmitted signal. The communication system in the present invention is able to help mitigate the effects of multipath. Previous attempts to mitigate the effects of multipath suffer from various problems: increased complexity needed to measure channel parameters and a feedback loop to switch the transmit antenna based on the parameters. The system is particularly useful when deployed in a MAS system or a jamming system.