National Instruments Corporation

Nxp Usa, Inc.

Karl F Nieman

Nikhil U Kundargi

Ian C Wong

Junmo Sung

James Wesley McCoy

Khurram Waheed

Lothar Wenzel

Brooks C Prumo

Marcus Monroe

Methods and wireless devices for selecting a local oscillator frequency to use for conducting orthogonal frequency division multiplexing (OFDM) communications. For each of a plurality of local oscillator frequencies, a wireless device determines a respective interference power resultant from the local oscillator frequency for each of a plurality of subcarriers, and determines a cost function by performing a summation over the interference powers associated with each of the plurality of subcarriers. The wireless device selects a first local oscillator frequency with the smallest cost function to use for wireless communications. The wireless device performs wireless communications through the plurality of subcarriers using the first local oscillator frequency.

Local oscillator placement for mixed numerology in orthogonal frequency division multiplexing communications

A wireless cellular base station (BS) transmitter transmits a downlink calibration pilot symbol. A receiver receives from a user equipment (UE) an uplink calibration pilot symbol and an effective downlink channel estimate transmitted by the UE. The effective downlink channel estimate is computed by the UE using the downlink calibration pilot symbol received from the BS. Processing devices compute an effective uplink channel estimate using the uplink calibration pilot symbol received from the UE and compute channel reciprocity calibration coefficients using the effective downlink channel estimate received from the UE and the effective uplink channel estimate computed by the BS. The BS includes multiple antennas, and the BS computes the channel reciprocity calibration coefficients for each antenna. Alternatively, the uplink channel estimate received by the BS is an inverted version of the effective downlink channel estimate, which the processing devices use for channel reciprocity compensation.

UE-aided channel reciprocity compensation for radio access in MIMO wireless communication systems

Techniques are disclosed relating to a massive MIMO base station architecture. In some embodiments, a base station is configured to combine signals received by multiple antennas and, for at least a subset of processing elements included in the base station, each processing element is configured to operate on a different portion of the combined signals. In these embodiments, each portion includes signals from multiple antennas. In some embodiments, the portions are different time and/or frequency portions of the combined signals. In some embodiments, this distributed processing may allow the number of antennas of the base station to scale dramatically, provide dynamic re-configurability, facilitate real-time reciprocity-based precoding, etc.

Massive MIMO architecture

A method for reducing complexity of downlink signal demodulation in a multiuser (MU) multiple-input-multiple-output (MIMO) wireless communication system includes a base station acquiring uplink (UL) channel state information (CSI) of a MIMO channel between the base station and a user equipment (UE), deriving downlink (DL) CSI from the UL CSI, and transmitting orthogonal frequency-division multiplexing (OFDM) radio subframes using MIMO pre-equalization based on the DL CSI. The UE performs downlink reciprocity correction of the OFDM subframes received from the base station using a single complex phasor estimate and performs downlink data demodulation of the downlink reciprocity corrected OFDM subframes without performing additional MIMO equalization.

Reduced-complexity downlink (DL) signal demodulation using reciprocity reference signals for MIMO wireless communication systems

Embodiments are disclosed for a new unified and flexible frame structure for 5G (5generation) mobile telecommunications standard and related radio access technology (RAT). The disclosed embodiments use communication frames with multiple partition types and are able to span a wide range of 5G deployment scenarios in a flexible and scalable manner.

Unified flexible radio access technology (RAT) for 5G mobile communication systems

A system and method for performing multi-user random access procedures in a mobile telecommunications network between a base station and a user equipment (UE) having a plurality of antennas includes transmitting a random access signal set (RASS) message using one or more antennas of the plurality of UE antennas. In response to receiving the RASS message, the base station transmitting a random access response physical downlink control channel (RAR-PDCCH) message. In response to receiving the RAR-PDCCH message, transmitting a reciprocity reference signal set (RRSS) signal using the plurality of UE antennas.

Multi-user random access procedures for massive MIMO wireless communication systems

A wireless cellular base station includes M antennas and one or more processing devices. For each antenna, the antenna transmits a calibration pilot symbol over the air and the other M&#x2212;1 antennas receive the calibration pilot symbol over the air. The processing devices select one of the M antennas as a reference antenna and for each antenna of the M antennas, the processing devices calculate channel reciprocity calibration coefficients of the antenna with respect to the reference antenna based on the received calibration pilot symbols.

Intra-node channel reciprocity compensation for radio access in MIMO wireless communication systems

Techniques are disclosed relating to signaling and frame structure for massive MIMO communication systems. In some embodiments, an apparatus is configured to receive an uplink pilot symbol from a mobile device over a first channel and receive uplink data from the mobile device over the first channel, where the uplink data is included in one or more orthogonal frequency division multiplexing (OFDM) symbols at a symbol rate. In these embodiments, the apparatus is configured to, determine channel information based on the pilot symbol, precode downlink data based on the channel information, and transmit the precoded downlink data to the mobile device. In these embodiments, a transition interval between receiving the uplink pilot symbol and beginning to transmit the precoded downlink data corresponds to less than five OFDM symbols at the symbol rate. This may facilitate reciprocity-based precoding for fast-moving mobile devices, in some embodiments.

Signaling and frame structure for massive MIMO cellular telecommunication systems

A method and apparatus for an orthogonal frequency division multiplexed (OFDM) communication system for communication in the presence of cyclostationary noise is provided. A receiver receives from a medium a channel measurement packet of a communication channel. The channel measurement packet has a measured transmission characteristic. The measured transmission characteristic of the received channel measurement packet is compared to a defined transmission characteristic to provide a comparison. A modulation coding scheme (MCS) map referenced to a phase of a cyclostationary noise period of the medium is generated based upon the comparison. The MCS map is sent to a transmitter via the medium. Signals including packets that have been mapped to subcarriers based on the MCS map are received from the medium. Subcarriers of the signals received from the medium are demapped using the MCS map referenced to the phase of the cyclostationary noise period of the medium.

Adaptive cyclic channel coding for orthogonal frequency division multiplexed (OFDM) systems

Techniques are disclosed relating to massive MIMO communications. In some embodiments, a base station is configured to dynamically adjust the number of processing elements used for MIMO signal estimation (e.g., the number of MIMO RX chains used for parallel processing). In some embodiments, the number of processing elements may be based on the number of antennas currently being used, the number of spatial streams, interconnect throughput thresholds, sampling rate, etc. In some embodiments, the base station includes configurable MIMO cores configured to dynamically switch between MIMO signal estimation techniques, e.g., on a per-symbol basis. In some embodiments, the base station includes configurable linear decoders configured to separately multiply input matrices and combine or refrain from combining the results based on the number of antennas and/or processing elements currently in use.

Scalable massive MIMO

Techniques are disclosed relating to synchronization of radios in a large antenna count (LAC) system. In some embodiments, a LAC system includes a plurality of slave radios, a clock and trigger distribution system, and a master device. In these embodiments, the plurality of slave radios are configured to establish a fixed relationship between a reference clock and their respective local clocks. In these embodiments, the master device and plurality of slave radios are configured to generate and align respective common periodic time reference (CPTR) signals, at a lower frequency than the local clocks. In these embodiments, the master device is configured to transmit a trigger signal based on its CPTR and the plurality of slave radios are configured to perform an action based on the trigger at a subsequent edge of their CPTRs. This may allow synchronization of sampling for antennas in a massive MIMO base station, for example. In some embodiments the master device a radio and includes a local clock, is configured to establish and maintain a fixed relationship between a reference clock and its local clock, and is configured to perform an action based on the trigger at the subsequent edge of its CPTR.

Growing community of inventors

Austin, TX, United States of America

Karl F Nieman