Qualcomm Incorporated

Srikant Jayaraman

John Edward Smee

June Namgoong

Ivan Jesus Fernandez Corbaton

Peter J Black

Ivan Jesus Fernandez-Corbaton

Hao Xu

Matthew Stuart Grob

Paul Eric Jacobs

Ruoheng Liu

Rajakumar Ebenezar Devairakkam

Bin Tian

Ahmad Jalali

Venkatraman Rajagopalan

Hai Truong Le

Sunil Kumar Kamavaram

Chih-Hao Liu

Fatih Ulupinar

Dan Vassilovski

Gene Wesley Marsh

Rohit Kapoor

Michael Alexander Howard

Charles Wheeler Sweet, Iii

William G Ames

Kundan Kumar Lucky

Michael John Mangan

Kalyan Kuppuswamy

Wenquan Hu

Ebenezer Pugalenthi Samuel

Chanakya Malladi

Sunil Kamavaram

Hai Le

Matthew S Qualcomm Incorporated Grob

Various aspects of the present disclosure generally relate to wireless communication. Various aspects relate generally to determining information metrics associated with an eigenvalue decomposition (EVD) operation associated with a four by four Hermitian matrix. Some aspects more specifically relate to determining a scalar (e.g., an eigenvalue or an approximation of an eigenvalue) of the four by four Hermitian matrix and determining a shifted matrix by subtracting a product of the scalar and an identity matrix from the four by four Hermitian matrix. A QR decomposition may be performed on the shifted matrix to determine first derived information, representable by a three by three Hermitian matrix. An eigenvalue decomposition operation may be performed on the three by three Hermitian matrix to determine the eigenvalues and eigenvectors of the four by four Hermitian matrix.

Performing a two-stage decomposition on a four by four Hermitian matrix associated with a wireless communication signal analysis

Various aspects of the disclosure relate to managing ephemeris information. Provisions are made for providing ephemeris information to a user terminal (UT). Messages are defined for sending ephemeris information and for requesting ephemeris information. Ephemeris information for a subset of the satellites in a constellation may be sent to a UT to reduce signaling load. A UT may manage a database of ephemeris information to ensure freshness of the ephemeris information.

Ephemeris information management for satellite communication

Aspects of the present disclosure generally relate to techniques and apparatus that may help improve greatly reduce the implementation complexity of the ground station, and ground base-station user capacity by utilizing a subband beamformer for processing uplink signals received from aircraft at ground base stations, in an air-to-ground (ATG) system. The techniques presented herein may allow for dynamic subband allocation to different airborne devices with multi-user beamforming and subband combining.

Air-to-ground (ATG) uplink subband beamformer with combinable subbands

Managing handover procedures of two or more modems from a serving base station to a target base station includes receiving at least one message indicative of at least one measurement report of radio conditions from at least one modem of the two or more modems; determining, based on the at least one message, whether to handover the two or more modems from the serving base station to the target base station; and upon determining to handover the two or more modems from the serving base station to the target base station, indicating to each of the two or more modems to send to the serving base station a measurement report configured to trigger a respective handover procedure from the serving base station to the target base station.

Handover management in air-to-ground wireless communication

Methods, systems, and devices are described for implementing timing advances in which a propagation delay may exceed a time period of a portion of a radio frame. In some examples, a transmitter may identify a timing advance indicating a time to initiate wireless uplink transmission of a subframe. Such a timing advance may compensate for a propagation delay between the transmitter and a receiver of the wireless uplink transmission. The timing advance may be applied as an integer component and a fractional component in relation to a duration of the subframe, to adjust the time to initiate the wireless uplink transmission of the subframe. The integer component may be used to adjust one or more subframe characteristics, and the fractional component that may be used to adjust the time to initiate the wireless uplink transmission of the subframe.

Timing advance techniques for large cells

Methods, systems, and devices are described for transmitting across a broad azimuth using an antenna array. In one example, a method is described that includes forming two subarrays from an antenna array. Beamforming weights are selected for each subarray to cause the radiation patterns to be complementary over a range of the azimuth of a cell. The beamforming weights may be selected according to a recursive relation based on the number of antenna elements in each subarray. Information may be encoded, scrambled, and mapped to modulation symbols. A Space Frequency Block Code (SFBC) such as an Alamouti Code may then be used to form two signals to be transmitted over the two subarrays.

Using subarrays of a beamformer for transmissions in a forward link

Methods, systems, and devices are described for establishing a wireless communications link at an aircraft terminal (AT). An AT may determine a timing offset based on the propagation delay between the AT and a ground station, which in some cases may be more than 100 kilometers away. The AT may then transmit an initial access message to the ground station based on the determined timing offset. In some embodiments, the AT may receive an access response message from the ground station that includes a timing alignment value and adjust the timing offset based on this value. The AT may transmit a connection message to the ground station that includes AT location information. This information may be used by the ground station to facilitate beamforming.

Enhanced random access procedure for air-to-ground communications

Synchronized broadcast transmits a same broadcast content using a same waveform from multiple transmitters. Transmitters each apply a same spreading code for broadcast transmissions. In a spread-spectrum communication system having a time division multiplexed forward link, a synchronized broadcast transmission is inserted into a broadcast slot. One embodiment employs an Orthogonal Frequency Divisional Multiplex (OFDM) waveform for the synchronized broadcast. An OFDM receiver is then used to process the received synchronized broadcast transmission. An alternate embodiment implements a broadcast Pseudo-random Noise (PN) code for use by multiple transmitters. An equalizer is then employed to estimate the synchronized broadcast transmission.

Synchronized broadcast/multicast communication

In a synchronous application to control forward link (FL) data rates in a satellite system, user equipment (UE) repeatedly transmits a quality control measurement (QCM) index during a QCM period. During this QCM period, the data rate cannot change. The associated satellite transmits at a new rate corresponding to the QCM index. The UE knows that it will begin receiving new data at the new rate after a QCM delay. In an asynchronous application, a satellite transmits a rate change signal over a FL rate indication channel (RICH). A UE monitors the FL RICH for this signal. When the signal quality is to be low, the satellite sends only a single bit of the QCM index over a first orthogonal channel. When the signal quality is not low, the satellite transmits each bit of the QCM index in a separate orthogonal channel of the FL RICH.

Forward link data rate control and rate indication for satellite-enabled communications systems

Reverse link data rate indications in wireless communication systems are defined with low identification overhead. Existence of a pilot signal is leveraged in order to reduce the overhead for identifying and selecting the reverse link data rate. At least two distinguishable pilot signals are defined, in which, based on the particular pilot signal present in the transmitted frame, at least one rate set from the multiple available rate sets can be determined. Reverse rate information in the transmitted frame is then used to identify which specific data rate within the determined rate set is used. Based on the identified data rate, the receiver may then decode the payload data in the transmitted frame.

Reverse link data rate indication for satellite-enabled communications systems

Systems and methods for adaptively allocating resources between a dedicated reference signal and a traffic signal are disclosed. In an exemplary embodiment, a wireless communication systemincludes a base station. The base stationincludes a receiverthat receives a quality metricfrom a remote station. The quality metricindicates the quality of a signal transmitted from the base stationand received by the remote station. The base stationalso includes a resource allocation componentthat uses the quality metricto allocate a resource between the traffic signaland the dedicated reference signal. The base stationalso includes a transmitterthat transmits the traffic signaland the dedicated reference signalto the remote station

Systems and methods for adaptively allocating resources between a dedicated reference signal and a traffic signal

A time averaging filter for channel estimation is described. Different time averaging is used for different taps or tones of a communication system. Two methods are suggested for determining the time-averaging filter for channel estimation for the communication systems without prior knowledge of SNR, channel Doppler and fading statistics. The first method includes a bank of different filters, each tuned for optimality in a certain range of SNR and Doppler. For each tone in the frequency domain (or tap in the time domain), the first method selects a filter among the set of filters that minimizes a certain computed metric. The second method directly computes, at each tone (or tap), the 'best' filter in a least-squares sense, using empirically determined second-order statistics.

Growing community of inventors

San Diego, CA, United States of America

Srikant Jayaraman