Search

KR-20260064906-A - Method of designing adaptive codebook for vehicle-to-vehicle communications under different road structures and traffic conditions, and apparatus for the same

KR20260064906AKR 20260064906 AKR20260064906 AKR 20260064906AKR-20260064906-A

Abstract

A technology is disclosed for designing a codebook for inter-vehicle wireless communication by executing a codebook design program on a codebook design device. Based on road structure and traffic parameter information, a mobility model, and the primary communication distance (R) required for inter-vehicle communication, a vehicle distribution function representing the distribution of vehicles on the road is obtained. Based on the vehicle distribution function, the beam width of the beam pattern to be generated by each codeword of the codebook is set. Based on the ideal beam pattern that creates the set beam width, codewords optimized for the hardware of the inter-vehicle communication system installed on vehicles on the road are designed.

Inventors

  • 김성철
  • 김근우

Assignees

  • 서울대학교산학협력단

Dates

Publication Date
20260508
Application Date
20241030

Claims (19)

  1. A method for designing a codebook for inter-vehicle wireless communication by executing a codebook design program on a codebook design device, A step of obtaining a vehicle distribution function representing the distribution of vehicles on the road based on road structure and traffic parameter information, a mobility model, and the main communication distance (R) required for inter-vehicle communication; A step of setting the beam width of the beam pattern to be generated by each codeword of the codebook based on the obtained vehicle distribution function; and A method for designing a codebook for inter-vehicle wireless communication, characterized by including the step of designing codewords optimized for the hardware of a V2V communication system installed on vehicles on a road, based on an ideal beam pattern that creates a set beam width.
  2. A method for designing a codebook for wireless communication between vehicles, characterized in that, in claim 1, the vehicle distribution function is a cumulative distribution function (cdf) or a probability density function (pdf) of vehicles existing on a road.
  3. A method for designing a codebook for inter-vehicle wireless communication according to claim 1, wherein the step of obtaining the vehicle distribution function comprises: a step of obtaining the average number of vehicles existing within a circle of radius R based on a transmitting vehicle on the road by applying a mobility model expressed by specific traffic parameters; a step of obtaining the average number of vehicles existing within a sector of radius R and a central angle θ based on the transmitting vehicle; and a step of obtaining a cumulative distribution function (cdf) in which other vehicles exist within a central angle θ centered on the transmitting vehicle by dividing the average number of vehicles within the sector of central angle θ by the average number of vehicles existing within the circle of radius R.
  4. A method for designing a codebook for wireless communication between vehicles, characterized in that, in claim 3, the step of obtaining the vehicle distribution function further includes the step of obtaining the probability density function (pdf) representing the distribution probability density of vehicles according to the central angle θ by partially differentiating the obtained cumulative distribution function (cdf) with respect to the central angle θ of the sector.
  5. A method for designing a codebook for wireless communication between vehicles, characterized in that, in claim 4, the cumulative distribution function (cdf) and/or the probability density function (pdf) are each calculated separately for various road structures including straight roads, L-shaped roads, T-shaped roads, intersections, and roundabouts.
  6. A method for designing a codebook for wireless communication between vehicles according to claim 1, wherein the step of setting the beam width of the beam pattern includes the step of setting a relatively thin beam width in the direction where the probability of a vehicle existing is high and setting a relatively wide beam width in the direction where the probability of a vehicle existing is low, based on the vehicle distribution function according to the central angle θ.
  7. A method for designing a codebook for inter-vehicle wireless communication according to claim 1, further comprising the step of grouping the designed codewords into one to form a codebook.
  8. A method for designing a codebook for inter-vehicle wireless communication, characterized in that, in claim 1, the step of setting the beam width of the beam pattern comprises dividing the entire angle range of the azimuth angle based on the transmitting vehicle into a plurality of angles of beam width, wherein the plurality of angles of beam width are set such that the average number of vehicles probabilistically existing within each angle range of the entire divided angles is the same.
  9. A method for designing a codebook for inter-vehicle communication according to claim 8, characterized in that the codeword creating the set beam width is designed using an orthogonal propagation method (OPM) algorithm.
  10. A method for designing a codebook for wireless communication between vehicles according to claim 1, characterized in that the traffic parameter information is information obtained by the sensor unit of the codebook design device sensing and analyzing the traffic conditions of vehicles on surrounding roads in real time.
  11. In a device for designing a codebook applied to a wireless communication system between vehicles, A vehicle detection sensor unit that senses the traffic conditions of vehicles on surrounding roads in real time; A storage unit storing a codebook design program, traffic parameter data detected by the vehicle detection sensor unit, structure information of a set surrounding road, a mobility model, and key communication distance (R) information required for communication between vehicles; and By executing the above codebook design program, the operation control unit performs the following tasks: (i) obtaining a vehicle distribution function representing the distribution of vehicles on the road based on real-time traffic parameter data, set surrounding road structure information, a mobility model, and the above main communication distance (R); (ii) setting the beam width of the beam pattern to be generated by each codeword of the codebook based on the obtained vehicle distribution function; and (iii) designing codewords optimized for the hardware of the V2V communication system installed on the vehicles on the road based on an ideal beam pattern that creates the set beam width. A codebook design device for inter-vehicle wireless communication characterized by adaptively designing a codebook according to road structure and traffic conditions.
  12. In paragraph 11, it further includes a communication unit configured to support wireless communication with wireless communication systems installed on vehicles on surrounding roads, A codebook design device for inter-vehicle wireless communication, characterized in that the above-described operation control unit further performs the task of grouping designed codewords into one to form a codebook and broadcasting it to vehicles on surrounding roads through the above-described communication unit so that the codebook can be applied to the vehicles.
  13. A codebook design device for inter-vehicle wireless communication, characterized in that, in claim 11, the vehicle distribution function is a cumulative distribution function or a probability density function of vehicles existing on a road.
  14. A codebook design device for inter-vehicle wireless communication, characterized in that, in claim 11, the operation of obtaining the vehicle distribution function comprises: (i) obtaining the average number of vehicles existing within a circle of radius R based on a transmitting vehicle on the road by applying a mobility model expressed by specific traffic parameters; obtaining the average number of vehicles existing within a sector of radius R and a central angle θ based on the transmitting vehicle; and obtaining a cumulative distribution function (cdf) in which other vehicles exist within a central angle θ centered on the transmitting vehicle by dividing the average number of vehicles within the sector of central angle θ by the average number of vehicles existing within the circle of radius R.
  15. A codebook design device for inter-vehicle wireless communication, characterized in that, in claim 14, the operation of obtaining the vehicle distribution function further includes the operation of obtaining the probability density function (pdf) representing the distribution probability density of vehicles according to the central angle θ by partially differentiating the obtained cumulative distribution function (cdf) with respect to the central angle θ of the sector.
  16. A codebook design device for wireless communication between vehicles according to claim 11, characterized in that the operation of setting the beam width of the beam pattern includes setting a relatively thin beam width in the direction where the probability of a vehicle existing is high and setting a relatively wide beam width in the direction where the probability of a vehicle existing is low, based on the vehicle distribution function according to the central angle θ.
  17. A codebook design device for inter-vehicle wireless communication, characterized in that, in claim 11, the operation of setting the beam width of the beam pattern includes dividing the entire angle range of the azimuth angle based on the transmitting vehicle into a plurality of beam width angles, and setting the plurality of beam width angles such that the average number of vehicles probabilistically existing within each angle range of the entire divided angles is the same.
  18. A computer executable program stored on a computer-readable recording medium for performing a method for designing a codebook for wireless communication between vehicles as described in any one of claims 1 to 10.
  19. A computer-readable recording medium having a computer program recorded thereon for performing a method for designing a codebook for wireless communication between vehicles as described in any one of claims 1 to 10.

Description

Method of designing adaptive codebook for vehicle-to-vehicle communications under different road structures and traffic conditions, and apparatus for the same The present invention relates to vehicle-to-vehicle communication technology, and more specifically, to design technology for a codebook applied to a vehicle-to-vehicle (V2V) communication system that supports communication between vehicles traveling on a road. Autonomous driving has emerged as a promising technology capable of revolutionizing the transportation industry with the potential to reduce traffic congestion and improve road safety. One of the critical considerations in the development and deployment of autonomous vehicles is their ability to communicate effectively with one another. In actual vehicle-to-vehicle communication systems, data rates of several Gbps are expected to be required to share visual signals, sensor data from inertial measurement units, and wireless messages. However, existing vehicle communication standards do not meet these requirements. On the other hand, communication systems operating in the millimeter wave (mmWave) band are considered an emerging technology for practical V2V communication systems due to their wide bandwidth. The millimeter wave band experiences significantly higher path loss compared to the ultra-high frequency band due to reduced antenna cross-sectional area and increased atmospheric attenuation. Higher expected path loss leads to significant degradation in communication performance, which may necessitate additional signal processing. Therefore, millimeter wave communication systems extensively utilize Multiple Input Multiple Output (MIMO) processing, which leverages directional signal transmission to achieve substantial beamforming gains. In MIMO communication systems, multiple antennas are used to transmit data. Each antenna can adjust the signal to be transmitted so that the signal is concentrated in a specific direction, thereby allowing the signal to be delivered more strongly to the receiver. When transmitting data in a wireless communication system, the data is converted into a specific signal pattern; this signal pattern is called a codeword, and a collection of these codewords is called a codebook. In other words, a codebook defines which signal pattern to use for specific data. Due to limited bandwidth and power constraints in a wireless communication environment, not all possible signals can be used during data transmission. A codebook optimizes data transmission by selecting the most efficient signal pattern. Furthermore, since signals can be distorted or lost in a wireless communication environment, using a codebook allows for the recovery of the original data even if an error occurs, by designing it so that, for example, a specific codeword can be sufficiently distinguished from other codewords. Due to these advantages of codebooks, codebook-based beam alignment methods are widely used in mmWave communication systems because they allow for the simple acquisition of effective transmission beamformers, even though they are suboptimal. Beam alignment systems require a predefined set of beamforming codewords to facilitate both channel integrity and data transmission. For example, LTE and New Radio (NR) use codebooks built based on Discrete Fourier Transform (DFT) codebooks that generate equally spaced beam patterns in the spatial frequency domain. Non-patent literature 1 below proposes a beam design algorithm that generates beam patterns covering equally spaced beam regions in a two-dimensional spatial frequency domain. Additionally, non-patent literature 2 presents a multi-resolution codebook design method in which each codeword at a specific level covers the same angular range. Furthermore, non-patent literatures (3) and (4) respectively propose an adaptive beam design strategy for V2I (vehicle-to-infrastructure) networks and a codebook design framework for reconfigurable intelligent surface-assisted V2V networks, taking into account the statistical distribution of vehicles in a road environment. However, codebooks according to the prior art are configured to generate beam patterns within beam areas of equal spacing without considering the adjustment of the beam width of each codeword's beam pattern. In other words, in the case of existing MIMO communication codebooks, the codebook is designed to generate beam patterns with uniform beam widths under the assumption that all transmitters and receivers are uniformly distributed in space. A codebook composed of codewords with uniform beam widths can be useful in environments where users are uniformly distributed in the spatial frequency domain, such as cellular networks. However, a codebook with beam widths of equal spacing may not be suitable for beamforming in Vehicle-to-Vehicle (V2V) networks. This is because the spatial frequency distribution between vehicles on the road is not uniform. In a V2V communication environment, since each ve