# US 10,320,061 B2 · High dimensional (HiDi) radio environment characterization and representation

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- Number: US 10,320,061 B2
- Document ID: US10320061B2
- Status: Granted
- Kind: B2
- Application number: 16/030,704
- Filed: 2018-07-09
- Published: 2018-12-13
- Granted: 2019-06-11
- Earliest claimed: 2016-12-16
- Assignees: Futurewei Technologies, Inc.
- Applicants: Futurewei Technologies, Inc.
- Inventors: Guosen Yue; Xiao-Feng Qi
- Web page: https://patentgrep.com/patent/US10320061B2

## CPC

- H01Q 1/246: {specially adapted for base stations}
- G01S 5/02521: {using a radio-map}
- G01S 5/0268: {by deriving positions from different combinations of signals or of estimated positions in a single positioning system}
- H01Q 21/00: Antenna arrays or systems (arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00)
- H04B 1/0003: {Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain (digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00)}
- H04B 1/0007: {wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage}
- H04L 5/0023: {Time-frequency-space}
- H04W 4/025: {using location based information parameters}
- H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A device comprises a memory that stores instructions executed by one or more processors to obtain a plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network. A plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network are obtained, and a plurality of complex channel values are calculated in an angle domain for a horizontal arrival angle and a vertical arrival angle per a received ray in a plurality of received rays in response to the plurality of received signals. An expected value of the plurality of channel values are calculated to obtain a power value for the horizontal arrival angle and vertical arrival angle having a time delay per the received ray.

## Claims

### Claim 1

A device, comprising:
a non-transitory memory storing instructions; and
one or more processors in communication with the non-transitory memory, wherein the one or more processors execute the instructions to:
obtain a plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network;
calculate a plurality of complex channel values in an angle domain for a horizontal arrival angle and a vertical arrival angle per a received ray in a plurality of received rays in response to the plurality of received signals, and
calculate an expected value of the plurality of channel values to obtain a power value for the horizontal arrival angle and vertical arrival angle having a time delay per the received ray.

### Claim 2 (depends on 1)

The device of claim 1, wherein the plurality of complex channel values for a horizontal arrival angle and a vertical arrival angle per a received ray having a delay per received ray is compensated with a time-offset estimate for the plurality of complex channel values.

### Claim 3 (depends on 2)

The device of claim 2, wherein a time-offset estimate for the plurality of complex channel values is calculated as the smallest time delay of the plurality of channel values in time domain.

### Claim 4 (depends on 1)

The device of claim 1, wherein obtain the plurality of received signals include obtain a plurality of orthogonal frequency-division multiplexing (OFDM) signals and the plurality of antenna elements are included in a multiple-input and multiple-output (MIMO) antenna.

### Claim 5 (depends on 4)

The device of claim 4, wherein the plurality of OFDM signals include a plurality of sounding reference signals in a plurality of subcarrier signals of a resource block transmitted by the user equipment.

### Claim 6 (depends on 5)

The device of claim 5, wherein calculate a plurality of complex channel values in the angle domain includes: obtain an angle domain-based channel estimation and providing the plurality of received signals to the angle domain-based channel to obtain the plurality of complex channel values.

### Claim 7 (depends on 6)

The device of claim 6, wherein obtain the angle domain-based channel estimation includes using an array signal processing that includes one of N-point discrete Fourier transform (DFT) steering, minimum variance distortionless response (MVDR) and multiple signal classification (MUSIC).

### Claim 8 (depends on 1)

The device of claim 1, wherein the one or more processors execute the instructions to: obtain a geographical location for the user equipment and store the power value, the horizontal arrival angle, vertical arrival angle and a second time delay per the received ray for the geographical location in another non-transitory memory.

### Claim 9 (depends on 8)

The device of claim 8, wherein the device is included in a base station having the plurality of antenna elements for communicating with the user equipment in the cellular network, wherein the one or more processors execute the instructions to: retrieve the power value, the horizontal arrival angle, vertical arrival angle and a second time delay per the received ray for the geographical location to use in one of user handover, radio resource management, link adaptation and channel estimation in the base station.

### Claim 10

A computer-implemented method for a base station having a plurality of antennas to communicate with a user equipment in a cellular network, comprising:
receiving a plurality of subcarrier signals in an orthogonal frequency-division multiplexing (OFDM) signal at a plurality of time intervals transmitted by the user equipment from the plurality of antennas;
calculating the channel values in a frequency domain in response to the plurality of subcarrier signals;
vectorizing the channel in the time domain to obtain a vector of the channel in the time domain; and
correlating the vector to obtain a spatial-time correlation.

### Claim 11 (depends on 10)

The device of claim 10, wherein the channel in the frequency domain is compensated by applying the time-offset estimated in the time domain.

### Claim 12 (depends on 11)

The device of claim 11, wherein the time-offset estimation is calculated with channels obtained from received subcarrier signals.

### Claim 13 (depends on 10)

The computer-implemented method of claim 10, wherein the plurality of subcarrier signals include a plurality of sounding reference signals in a resource block transmitted by the user equipment.

### Claim 14 (depends on 13)

The computer-implemented method of claim 13, wherein calculating the frequency-offset estimation includes calculating the frequency-offset estimation based on an OFDM symbol index.

### Claim 15 (depends on 14)

The computer-implemented method of claim 14, wherein correlating the vector to obtain a spatial-time correlation includes correlating the vector to obtain an Eigen decomposition of the spatial time correlation with or without an average power value.

### Claim 16 (depends on 15)

The computer-implemented method of claim 15, further comprising:
obtaining a geographical location for the user equipment; and
storing the spatial-time correlation or Eigen decomposition of spatial-time correlation, with or without an average power value associated with the geographical location in a database stored in non-transitory memory.

### Claim 17 (depends on 16)

The computer-implemented method of claim 16, further comprising:
retrieving the spatial-time correlation or Eigen decomposition of spatial-time correlation, with or without an average power value associated with the geographical location; and
using the spatial-time correlation or Eigen decomposition of spatial-time correlation, with or without the average power value in a base station application that includes one of a user handover, radio resource management, link adaptation and channel estimation.

### Claim 18 (depends on 14)

The computer-implemented method of claim 14, wherein calculating the frequency-offset estimation is based on an OFDM symbol period and wherein calculating the time-offset estimation is based on a subcarrier spacing in an OFDM signal.

### Claim 19

A non-transitory computer-readable medium storing computer instructions, that when executed by one or more processors, cause one or more processors to:
receiving a plurality of subcarrier signals in an orthogonal frequency-division multiplexing (OFDM) signal at a plurality of time intervals transmitted by a user equipment from a plurality of antennas at a base station in a cellular network;
calculating channel values in a frequency domain in response to the plurality of subcarrier signals;
vectorizing the channel in frequency domain to obtain a vector of the channel in the frequency domain; and
correlating the vector to obtain a spatial-frequency correlation.

### Claim 20 (depends on 19)

The device of claim 19, wherein the channel in the frequency domain is compensated by applying the time-offset estimated in the time domain.

### Claim 21 (depends on 20)

The device of claim 20, wherein the time-offset estimation is calculated with channels obtained from received subcarrier signals.

### Claim 22 (depends on 19)

The non-transitory computer-readable medium of claim 19, wherein correlating the vector to obtain a spatial-frequency correlation includes correlating the vector to obtain an Eigen decomposition of the spatial-frequency correlation with or without an average power value.

### Claim 23 (depends on 22)

The non-transitory computer-readable medium of claim 22, further comprising computer instructions causing one or more processors to:
obtaining a geographical location for the user equipment; and
storing the spatial-frequency correlation or Eigen decomposition of the spatial-time correlation, with or without the average power value associated with the geographical location in a database stored in non-transitory memory.

### Claim 24 (depends on 23)

The non-transitory computer-readable medium of claim 23, further comprising computer instructions causing one or more processors to:
retrieving the spatial-frequency correlation or Eigen decomposition of the spatial-time correlation, with or without the average power value associated with the geographical location; and
using the spatial-frequency correlation or Eigen decomposition of the spatial-time correlation, with or without the average power value in a base station application that includes one of a user handover, radio resource management, link adaptation and channel estimation.

### Claim 25 (depends on 19)

The non-transitory computer-readable medium of claim 19, wherein calculating the frequency-offset estimation is based on an OFDM symbol period and calculating the time-offset estimation is based on an OFDM subcarrier spacing.

### Claim 26 (depends on 19)

The non-transitory computer-readable medium of claim 19, wherein the vectorizing is based on a number of frequency domain channel sampling points.

### Claim 27

A device, comprising:
a non-transitory memory storing instructions; and
one or more processors in communication with the non-transitory memory, wherein the one or more processors execute the instructions to:
obtain a plurality of received signals transmitted by a user equipment from a plurality of antenna elements in a cellular network;
calculate a plurality of complex channel values as raw channel estimate in a frequency domain in response to the plurality of subcarrier signals; and
filter the raw channel estimates with power angle delay profiles, spatial time correlation, or spatial frequency correlation to obtain improved channel estimates.

### Claim 28 (depends on 27)

The device of claim 27, wherein the power angle delay profiles are a plurality of received rays with each ray represented by a power value, a horizontal arrival angle and vertical arrival angle, a time delay per the received ray that are obtained by the measurement of the channel values in previous time slots.

### Claim 29 (depends on 27)

The device of claim 27, wherein the spatial time correlation is the correlating of the vectorized channel in spatial and time domain from the channel values in previous time slots.

### Claim 30 (depends on 27)

The device of claim 27, wherein the spatial frequency correlation is the correlating of the vectorized channel in spatial and frequency domain from the channel values in previous time slots.

### Claim 31

A computer-implemented method for a base station having a plurality of antennas to communicate with a user equipment in a cellular network, comprising:
receiving a plurality of subcarrier signals in an orthogonal frequency-division multiplexing (OFDM) signal at a plurality of time intervals transmitted by the user equipment from the plurality of antennas;
calculating the channel values in a frequency domain in response to the plurality of subcarrier signals;
transforming the channel values to the time domain;
generating a pseudo pilot sequence in the time domain;
obtaining the convolutional signal between the channel values and the pseudo pilot sequence for each antennal;
vectorizing the convolutional signal in the time domain for all antennas to obtain a vector of the convolutional signal in the spatial time domain; and
correlating the vector to obtain a spatial-time correlation.

### Claim 32 (depends on 31)

The device of claim 31, wherein the pseudo pilot sequence consists of a plurality of pilot symbols.

### Claim 33 (depends on 32)

The device of claim 32, wherein the pilot symbols of the pseudo pilot sequence have equal power.

### Claim 34 (depends on 31)

The device of claim 31, wherein the pseudo pilot sequence can be a predefined sequence.

### Claim 35

A computer-implemented method for a base station having a plurality of antennas to communicate with a user equipment in a cellular network, comprising:
receiving a plurality of subcarrier signals in an orthogonal frequency-division multiplexing (OFDM) signal at a plurality of time intervals transmitted by the user equipment from the plurality of antennas;
calculating the channel values in a frequency domain in response to the plurality of subcarrier signals;
generating a pseudo pilot sequence in the frequency domain;
obtaining the multiplication signal by multiplying each symbol of the pseudo pilot sequence in the frequency domain to the channel value on the corresponding subcarrier;
transforming the multiplication signal in the frequency domain to the time domain; vectorizing the transformed multiplication signal in time domain for all antennas to obtain a vector of the signal in the spatial time domain; and
correlating the vector to obtain a spatial-time correlation.

### Claim 36 (depends on 35)

The device of claim 35, wherein the pseudo pilot sequence consists of a plurality of pilot symbols.

### Claim 37 (depends on 35)

The device of claim 35, wherein the pseudo pilot sequence can be a predefined sequence.

### Claim 38 (depends on 35)

The device of claim 35, wherein the pseudo pilot sequence can be generated in time domain and transformed to the frequency domain.

### Claim 39 (depends on 38)

The device of claim 38, wherein the pilot symbols of the pseudo pilot sequence in time domain have equal power.