Cisco Technology, Inc.

Navini Networks, Inc.

John Grabner

Hang Jin

Daniel Wee

Li Guo

Ahmadreza Hedayat

Richard L Smith

Qingwen Liu

Weidong Yang

Mitch Johnson

Brian L Kurtz

Ed Condon

Wenhua Zhou

Jing Jiang

Yanxin Na

George Alexander Bednekoff

Philip B Davis

Bror Peterson

Santhalingam Balasekar

Edward B Condon

An Tuyen Banh

Weiguo Xie

Tuyen Banh

Phil Davis

Chris Sanders

Monte Curran

William Oliver

Jun Huang

Daniel Wee Teck Ho

Richard Smith

A calibration-less transmit beamforming apparatus and method are provided. In a wireless communication device that comprises a plurality of antennas, a gain block is provided in the front-end module associated with each antenna and the same gain block is used during transmit and receive operations. As a result, the transmit phase offset and receive phase offset for each antenna are made to be equal, thereby achieving conditions for transmit beamforming without the need for complex antenna calibration algorithms and hardware.

Calibration-less transmit beamforming

Techniques are provided herein to segment subcarriers for broadcast transmission to one or more mobile stations. A broadcast message to be transmitted from a first device is generated. The broadcast message comprises a plurality of symbols and each symbol is to be transmitted at a different one of a plurality of frequency subcarriers. The plurality of subcarriers is divided into groups and each group of subcarriers is assigned to a corresponding one of a plurality of antennas of the first device. The groups of subcarriers are transmitted from corresponding ones of the plurality of antennas.

Segmented transmission for broadcast messages using multiple antennas

A wireless base station apparatus is provided that is configured to automatically optimize the radiation pattern it uses when installed for operation in a wireless network in order to serve wireless client devices within a coverage area. The wireless base station is configured to determine its geographical location and to evaluate its geographical location based on stored geographical map data that indicates the physical geographical environment surrounding its geographical location. Based on the physical geographical environment surrounding the geographical location, the base station determines a radiation pattern best suited to serve wireless client devices within a coverage area.

Self-optimizing wireless network base station

A system and method are provided for improving the performance of a beamforming antenna array in a wireless communications system. By observing a predetermined times of channel spatial signatures, one or more test spatial signatures are generated based on statistical analysis of the observed spatial signatures for predicting channel characteristics. A beamforming weight is derived based on the generated test spatial signatures for beamforming by an antenna subsystem of the wireless communication system.

Method and system for transmitter beamforming

An offset direct conversion receiver apparatus and corresponding receiving method are provided. A received wireless signal is directly downconverted and demodulated to a baseband offset frequency that is offset from zero frequency to produce an in-phase (I) baseband offset signal centered at the baseband offset frequency and a quadrature-phase (Q) baseband offset signal centered at the baseband offset frequency. The I baseband offset signal and Q baseband offset signal are bandpass filtered to produce an I bandpass signal and a Q bandpass signal, respectively. The I bandpass signal and the Q bandpass signal are downconverted from the baseband offset frequency to zero frequency to produce an I baseband receive signal and a Q baseband receive signal. A technique and logic are also provided to select the best baseband offset frequency used in an offset direct conversion receiver.

Offset direct conversion receiver

Techniques are provided to pre-distort a signal that is transmitted by a transmitter of a wireless communication device, e.g., a device configured for wireless radio frequency communication. The transmitter of the device inherently introduces distortion to the baseband signal to be transmitted. In at least one frame of a baseband signal to be transmitted, at least one subcarrier in a preamble of the frame is shifted in frequency such that the at least one subcarrier is offset from a normal subcarrier frequency position. The at least one frame of the baseband signal is supplied to the transmitter that is configured to produce a transmit signal for transmission. The transmit signal at an output of the transmitter is sampled or detected and inter-modulation distortion in the transmit signal is determined at one or more frequencies as a result of shifting of the frequency of the at least one subcarrier in the preamble of the at least one frame. The baseband signal is pre-distorted based on the inter-modulation distortion prior to coupling to the transmitter for transmission.

Transmitter characterization for digital pre-distortion using offset preamble subcarriers

A hybrid time-spatial multiplexing technique is provided for beamforming broadcast messages to mobile stations that may be within a coverage region or cell of a base station. The coverage region is divided into a plurality of segments. The mobile stations are assigned to at least one of the segments based on their locations within the coverage region or other criteria. The base station computes beamforming antenna weights which are configured to produce a radiation beam pattern from a plurality of antennas of the base station to respective ones of each of the plurality of segments in the region. A broadcast message is transmitted to each segment of the region in a time-division multiplexed manner using the beamforming antenna weights associated with the radiation beam pattern for the corresponding segment.

Hybrid time-spatial multiplexing for wireless broadcast messages through antenna radiation beam synthesis

A system and method are provided for improving the performance of a beamforming antenna array in a wireless communications system. A predetermined number of spatial signatures are observed for a communications channel between a base station and a mobile terminal during a predetermined time period. One or more test spatial signatures are generated based on statistical analysis of the observed predetermined number of spatial signatures. A beamforming weight is derived based on the generated test spatial signatures for beamforming by an antenna subsystem of the base station.

A method and system are provided for detecting messages using enhanced distributed signaling in a wireless communication network that offers transmission diversity to improve the throughput of participating wireless stations.

Method and system for detecting messages using enhanced distributed signaling

A system and method for managing control information in a wireless communications system. The method comprises broadcasting a predetermined number of preambles through beamforming from a base station, detecting, by a subscriber station, a predetermined frame associated with one selected preamble that has the highest power level, and identifying one or more subcarriers for carrying control information through the selected preamble.

Method and system for control channel beamforming

Techniques are provided herein to optimize up-link transmission power from a wireless terminal to a base transceiver station in a multicarrier system. A pathloss between the wireless terminal and the base transceiver station is determined. A determination is made if the pathloss is less than or larger than a predetermined value. One or more sub-carriers are assigned to the wireless terminal based on whether the pathloss between the wireless terminal and the base transceiver station is less than or larger than the predetermined value. A power cap command signal is sent from the base transceiver station to the wireless terminal for limiting a maximum allowable power transmitted by the wireless terminal to a predetermined level based on proximity of the one or more sub-carriers to an edge of a frequency band used for up-link transmissions made by the wireless terminal.

Method for optimizing up-link transmission power for a wireless terminal in a multi-carrier system

Techniques are provided herein to combine the advantages of beamforming with the advantages of multiple-input multiple output (MIMO) technology in a frequency division duplex (FDD) communication system, even when the uplink and downlink frequency separation exceeds the coherent bandwidth of the over-the-air-channels. At a first wireless communication device having M plurality of antennas, a wireless transmission is received that is sent from a second wireless communication device having P plurality of antennas. The first device computes spatial components associated with the transmission received at the M plurality of antennas. The first device selects the N strongest spatial components among the computed spatial components. The first device computes N beamforming weight vectors based on the N strongest spatial components. The first device then computes N MIMO beamforming weight vectors based on the N beamforming weight vectors. The N MIMO beamforming weight vectors are applied to N signal streams to be transmitted via the plurality of antennas of the first device to the plurality of antennas of the second device.

Beamforming multiple-input multiple-output wireless techniques using spatial decomposition for frequency division duplex systems

A system and method are provided for configuring an antenna array having a predetermined number of antennas. After providing an antenna correlation matrix for all antennas with regard to a mobile terminal, the antenna array is virtually partitioned into two or more sub-arrays based on the antenna correlation matrix such that correlations among antennas within each sub-array are higher than correlations among antennas belonging to different sub-arrays. One or more beamforming weights are generated corresponding to each antenna within the sub-arrays for applying to one or more signals transmitted therefrom, and at least one predetermined multiple-input-multiple-output (MIMO) mechanism is further applied among the sub-arrays by treating each sub-array as a virtual antenna.

Method and system for partitioning an antenna array and applying multiple-input-multiple-output and beamforming mechanisms

A method is disclosed for optimizing up-link transmit powers of a wireless broadband terminal operating in a predetermined frequency band in a multi-carrier system, the method comprising assigning a transmit signal to one or more sub-carriers of predetermined frequencies, and capping the output powers of the transmit signal to a predetermined level based on the predetermined frequencies, wherein the output power of the transmit signal is lower if frequencies of the transmit signal have less guard band to the edge of the predetermined frequency band.

Method for up-link transmit power management in a wireless broadband terminal

A wireless communications system is provided with reduced sideband noise and carrier leakage. In the system, at least one transmitter modulates at least one input signal with a first carrier to generate a modulated output signal, and at least one receiver receives the modulated output signal and demodulates the same with a second carrier to generate at least one demodulated output signal. The first and second carriers are at different frequencies, such that the sideband noise and carrier leakage generated by different sources can be distinguished.

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Plano, TX, United States of America

John Grabner