Techniques for elevated device communication

Patent metadata

Field	Value
Publication number	US-11943022-B2
Application number	US-201917435587-A
Country	US
Kind code	B2
Filing date	Mar 29, 2019
Priority date	Mar 29, 2019
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

Systems and methods of beamforming and improving mmWave communications for drones are described. Multiple RF chains are used to adapt the main beam to track changes without the use of pilot signals. To reduce interference, interfering signal power is eliminated by optimizing a non-Gaussian measure to extract the interferers. The AoA of signals from a target drone on neighbouring drones and location of the neighbouring drones and base stations are used to independently corroborate the location reported by the target drone. The base station provides additional synchronization signals below 6 GHz and restricts the search/measurement space in the vertical direction. The inherent sparse structure above 6 GHz is exploited by applying different beamformers on a sounding signal and estimating the AoA and impulse response. Variations of fully digital and hybrid beamforming architectures for multi-cell DL sync and CRS measurement are described.

First claim

What is claimed is:

1. An apparatus of a drone, the apparatus comprising:
processing circuitry arranged to:
determine a position of the drone from reference signals received from a base station via beamforming;
generate a measurement report to the base station, the measurement report indicating height information of the drone;
decode higher layer signaling, from the base station, that contains a synchronization signal block (SSB) restriction pattern, the SSB restriction pattern dependent on a height of the drone such that the SSB restriction pattern when the height of the drone is above a predetermined threshold is different from the SSB restriction pattern when the height of the drone is below the predetermined threshold; and
for communications below 6 GHz, restrict search for and measurement of primary synchronization signals (PSSs) and secondary synchronization signals (SSSS) to restricted synchronization signal blocks (SSBs) indicated by the SSB restriction pattern; and

a memory configured to store the SSB restriction pattern.

2. The apparatus of claim 1 , wherein the processing circuitry is further arranged to:
decode the higher layer signaling when in a radio resource control (RRC) connected mode to change SSB restriction patterns, the higher layer signaling being RRC signaling for static signaling and RRC signaling and Medium Access Control (MAC) Control Element (CE) signaling for semi-static signaling.

3. The apparatus of claim 2 , wherein at least one of:
the SSB restriction pattern received is dependent on the height information transmitted,
the change in SSB restriction patterns is dependent on Unmanned Traffic Management (UTM) stored at the base station, or
the change in SSB restriction patterns indicates deactivation of upper vertical SS beams when the drone is below the base station.

4. The apparatus of claim 1 , wherein:
the SSB restriction pattern comprises a bitmap that indicates a number of SS beams to use in a vertical dimension, the bitmap configured to limit available SS beams to a subset of the available SS beams, each SS beam containing the PSSs and SSSs, and
the bitmap further indicates a number of SS beams to use in a horizontal dimension, the bitmap having a length of a product of the number of SS beams in the vertical dimension times the number of SS beams to use in the horizontal dimension.

5. The apparatus of claim 1 , wherein the processing circuitry is further arranged to:
decode, from the base station, other higher layer signaling that indicates an unused SSB among available SSBs, the unused SSB dependent on positions of all user equipment served by the base station and SSB restriction patterns of the user equipment.

6. The apparatus of claim 1 , wherein:
a number of available SSBs in a vertical dimension is larger than 4 when the communications are below 3 GHz and larger than 8 when the communications are between 3 GHz and 6 GHz.

7. The apparatus of claim 1 , wherein the processing circuitry is further arranged to:
engage in beamforming using a digital beamforming architecture, the digital beamforming architecture comprising:
an analog-to-digital converter (ADC) that digitizes N r , analog signals received from a plurality of antennas,
a plurality of synchronization signal (SS) detectors that determine coarse timing and fractional frequency offset (FFO) of SUR beamformed signals,
a beamforming network disposed between the ADC and the SS detectors, the beamforming network supplied with a N r dimension data sample vector to produce the N RF beamformed signals, the SS detectors configured to detect N SS cells from the N RF beamformed signals,
a plurality of fast Fourier transforms (FFTs) to which outputs of the SS detectors are provided,
fine timing and integer frequency offset (IFO) to determine fine timing and frequency offset synchronization of neighboring cells, and
measurement circuitry to measure at least one of Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) of a cell reference signal (CRS) of each of the neighboring cells.

8. The apparatus of claim 7 , wherein the digital beamforming architecture further comprises at least one of:
an FFT, demodulator and decoder configured to detect, demodulate and decode a Physical Downlink Control Channel and a Physical Downlink Shared Channel of the base station simultaneously with measurement of the at least one of the RSRP or RSRQ of the CRSs of the neighboring cells, or
a controller disposed between the SS detectors and the FFTs and configured to provide feedback to the beamforming network to adjust a beam direction to a neighboring cell having a stronger SS signal than that of a current cell.

9. The apparatus of claim 8 , wherein the processing circuitry is further arranged to:
control the controller based on Unmanned Traffic Management (UTM) information received from the base station.

10. The apparatus of claim 1 , wherein the processing circuitry is further arranged to:
engage in beamforming using a hybrid beamforming architecture, the hybrid beamforming architecture comprising:
an analog front end (AFE) to which signals from a plurality of antennas is supplied,
an analog-to-digital converter (ADC) that digitizes analog signals,
a beamforming network disposed between the AFE and the ADC, the beamforming network supplied with N r analog signals to produce N RF beamformed signals,
coarse timing and fractional frequency offset (FFO) circuitry configured to determine coarse timing and a FFO of the N RF beamformed signals,
a plurality of fast Fourier transforms (FFTs) configured to receive a beam controlled output of the coarse timing and FFO circuitry,
a controller disposed between the coarse timing and FFO circuitry and the FFTs and configured to provide feedback to the beamforming network to adjust a beam direction to a neighboring cell having a stronger signals than that of a current cell, and
fine timing and integer frequency offset (IFO) configured to receive an output of the FFTs and to determine fine timing and frequency offset synchronization of neighboring cells.

11. The apparatus of claim 1 , wherein the processing circuitry is further arranged to, for communications above 6 GHz:
determine a reference signal sub-carrier group assigned to the base station, the reference signal sub-carrier group having P frequency locations uniformly spaced across an entire bandwidth used by the base station,
use M random beamformers on M orthogonal frequency-division multiplexing (OFDM) symbols received on M different measurement beams by N r antenna elements, each random beamformer being a N r ×1 vector of independent random phases generated using N r phase shifters, where M<N r ,
perform channel sounding on the M OFDM symbols using a different beamformer for each OFDM symbol, where each OFDM symbol is N samples long with inter sub-carrier frequency δf bandwidth of N δf, and
perform channel estimation using M×P samples of the M OFDM symbols and detect an optimal beam, of the measurement beams, from a beamforming codebook that is able to differ from a measurement beamforming codebook used to measure pilot signals.

12. The apparatus of claim 11 , wherein at least one of:
the channel sounding is performed on consecutive OFDM symbols,
the channel sounding is performed using an estimation algorithm with parameters that are optimized beforehand using a machine learning algorithm and possibly on the measurement beams,
the N r phase shifters are circularly symmetric complex Gaussian vectors,
a receive measurement codebook used for beam selection and channel estimation is based on weighted pseudo random beamformi

Assignees

• Intel Corp

Inventors

• Nallampatti Ekambaram Venkatesan
• Choi Yang-Seok
• Nam Junyoung
• Xue Feng
• Yeh Shu-Ping
• Nikopour Hosein
• Talwar Shilpa
• Schreck Jan
• Himayat Nageen
• Dhakal Sagar

Classifications

• H04B7/0617 Primary

  for beam forming · CPC title

• H04B7/086

  using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming · CPC title

• H04W16/28

  using beam steering · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title

• H04W56/001

  Synchronization between nodes · CPC title