JP3854973B2 - Fading simulator - Google Patents

Description

  The present invention relates to a fading simulator that simulates a propagation environment using a three-dimensional model.

  The fading simulator is a device that creates a spatio-temporal characteristic of an actual communication environment by using a cable connected between a transmitter and a receiver. In this fading simulator, a propagation model is important when simulating an actual communication environment. In a conventional fading simulator, a generalized propagation model equation is used to generate reception level fluctuations due to time fluctuations with respect to distance, and a statistical model is used to determine the occurrence probability of multipaths and the level of each path. . Then, by changing the propagation channel stochastically in the fading simulator, the fading state is changed with the progress of time. The propagation channel is a path through which radio waves pass, and a fading phenomenon occurs when a plurality of propagation channels are erased from each other or added together.

  By the way, in the field of mobile communications, the third generation mobile phone service has begun, and the data transmission speed with respect to the number of accommodations and the number of subscribers has been greatly improved. This is because the time axis at the time of broadband transmission can be effectively used by introducing the access technology using the frequency spread technology.

  Currently, as a next step, system development using a technique that uses a plurality of antenna elements such as an array antenna and MIMO (Multi-Input Multi-Output) that make effective use of the spatial axis of multiple radio wave propagation is in progress. In order to cope with such a system, it is necessary not only to change the received power with respect to time but also to represent a space in order to accurately reproduce each path. The domain representation model is not functional enough.

Therefore, it is expected to develop a fading simulator using a three-dimensional model that can three-dimensionally express the traffic of radio waves and can determine a propagation channel from an actual three-dimensional map.
JP 2002-333659 A

  However, if the simulation concept using a two-dimensional model is directly converted to a three-dimensional model, all parameters of each antenna element are transferred from the propagation model generation device to the fading simulator, so the amount of data transferred between the devices (Communication traffic) becomes enormous, which hinders high-speed sequential transfer.

  The present invention has been made in view of this point, and an object of the present invention is to provide a fading simulator capable of simulating a propagation environment using a three-dimensional model with less communication traffic.

  In order to solve such a problem, the present invention is a fading simulator that simulates a propagation environment using parameters of a three-dimensional model generated by a propagation model generation device, and stores a spatial position of an antenna element of a base station Phase information storage means; phase calculation means for calculating the phase of each antenna element from the reference phase, horizontal direction arrival angle, vertical direction arrival angle parameter output from the propagation model generation device and the spatial position of the antenna element; And a fading generation means for generating a fading state of the propagation channel based on the received power and delay time parameters output from the propagation model generation device and the phase of each antenna element.

  According to the present invention, the parameters of the spatial model are common to all antenna elements, and the phase of each antenna element can be calculated from the spatial position of each antenna element and the horizontal / vertical arrival angle of radio waves. The simulation using the three-dimensional model can be performed with less communication traffic. Also, the number of antenna elements can be expanded by adding hardware without changing the program.

  The inventor of the present application can set the received power, delay time, and horizontal / vertical arrival angle of radio waves among the parameters of the three-dimensional model (spatial model) common to each antenna element, and only the phase of each antenna element In particular, the present inventors have made the present invention by paying attention to the difference between the antenna elements and the phase of each antenna element determined by the arrival angle of the radio wave in the horizontal / vertical direction and the position unique to each antenna element.

  That is, the essence of the present invention is that the parameters of the spatial model (reception power, reference phase, delay time, horizontal arrival angle, vertical arrival angle) are common to all antenna elements, and the spatial position of each antenna element and the horizontal / The phase of each antenna element is calculated from the angle of arrival in the vertical direction. The reference phase is the phase of a predetermined single antenna element.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment)
FIG. 1 is a system configuration diagram including a fading simulator according to an embodiment of the present invention.

  Propagation model generation apparatus 100 generates a spatial model and outputs the parameters of the spatial model to fading simulator 200. The fading simulator 200 simulates spatio-temporal characteristics of an actual communication environment using parameters of a spatial model, adds a spatial multipath to a signal output from the mobile device 300, and has a base station 400 having an array antenna. Output to.

  Next, the configuration of the propagation model generation apparatus 100 will be described using the block diagram of FIG. The propagation model generation apparatus 100 mainly includes a three-dimensional map data generation unit 101, a propagation environment construction unit 102, a channel impulse response acquisition unit 103, a spatiotemporal profile generation unit 104, and a parameter calculation unit 105. .

  The three-dimensional map data generation unit 101 generates three-dimensional map data using two-dimensional house map data such as actual field map / building information and altitude mesh data. The propagation environment construction unit 102 constructs a propagation environment in the base station using the three-dimensional map data and the base station data.

  The channel impulse response acquisition unit 103 receives data on the travel route of the mobile device, and estimates parameters such as the received electric field strength and the delay profile from the propagation environment constructed by the propagation environment construction unit 102 and the angle of arrival (Angle Of Arrival). ), Estimate the transmission angle (Angle Of Departure), and acquire the channel impulse response of the base station receiver.

  The spatio-temporal profile generation unit 104 receives data on the speed of the mobile device, and generates a spatio-temporal delay profile in the base station on the travel route of the mobile device by combining the channel impulse response and the arrival angle.

  The parameter calculation unit 105 acquires various parameters (reception power, delay time, horizontal arrival angle, vertical arrival angle) of the wave (ray) that has reached the base station receiver using the space-time delay profile, Output to fading simulator 200.

  Next, a processing procedure in the propagation model generation device 100 will be described.

  First, the propagation model generation device 100 creates environment data (three-dimensional city data) using the map / building information of the actual field. In this environment data, a complex dielectric constant is set for each obstacle material.

  Next, the propagation model generation apparatus 100 estimates the estimation parameters such as the received electric field strength, the delay profile, the arrival angle, and the transmission angle using the environment data by the ray tracing method, and the channel impulse of the base station receiver. Get the response.

  Representative ray tracing methods include a launching method (launching-method) and an image method (Imaging-method). The launching method is a method in which a wave (ray) is discretely emitted from a transmitter at Δθ to search for a radio wave path, and the receiver is traced while repeating reflection, transmission, and diffraction by an obstacle. The image method is a method of searching radio wave paths by creating virtual images of all transmitters. The image method can be used as a model for evaluating a relatively narrow area such as a room because the number of obstacles increases, but the number of combinations of paths searched exponentially increases as obstacles increase. The launching method increases the uncertainty of obstacle search (trace) due to the spread of discrete angles, but it is easy to devise speedup.

  In the ray tracing method, the received power is derived as the sum of all the rays that have arrived in the vicinity of the receiver, and the delay time is derived from the route length because the route of the arrived ray is clear. As a result of these, the channel impulse response of the receiver can be acquired. The maximum point that determines the estimation accuracy of the behavior of radio waves is 3D map data. In general, it is difficult to create a wide range of 3D map data, but the inventor has developed software that can automatically convert any area to a 3D from a house map.

  Next, propagation model generation apparatus 100 generates a spatio-temporal delay profile at the base station on the travel route of the mobile device by combining the channel impulse response and the arrival angle. A set of spatio-temporal delay profiles is a fading simulator space model.

  Next, the propagation model generation apparatus 100 uses the spatio-temporal delay profile to set various parameters (reception power, delay time, horizontal arrival angle, vertical arrival angle) of the ray that has reached the base station receiver. Is output to the fading simulator 200.

  The above is the description of the processing procedure in the propagation model generation device 100.

  Next, the configuration of fading simulator 200 will be described using the block diagram of FIG. The fading simulator 200 mainly includes a position information storage unit 201, phase calculation units 202 for the number of antenna elements, and fading circuits 203 for the number of antenna elements.

  In the position information storage unit 201, the spatial position of the antenna element of the base station is set / stored in advance by the user. The spatial position of each antenna element stored in the position information storage unit 201 is obtained by correcting the phase variation of each antenna element circuit.

  The phase calculation unit 202 calculates each antenna element from the reference phase, horizontal direction arrival angle, vertical direction arrival angle parameter output from the propagation model generation apparatus 100 and the spatial position of the antenna element stored in the position information storage unit 201. Calculate the phase.

  The fading circuit 203 generates a fading state of the propagation channel based on the received power and delay time parameters output from the propagation model generation apparatus 100 and the phase parameter of each antenna element calculated by the phase calculation unit 202. To do. Specifically, the fading circuit 203 delays the input signal according to the delay time output from the propagation model generation device 100. The fading circuit 203 sets a complex coefficient using received power and phase parameters, and multiplies the delayed input signal by the complex coefficient. As a result, the input signal from the mobile device or the like can be multipathed, phase rotation and level control can be performed for each path, and the spatiotemporal characteristics of the actual communication environment can be simulated.

  Thus, according to this embodiment, the parameters of the spatial model are common to all antenna elements, and by calculating the phase of each antenna element from the spatial position of each antenna element and the horizontal / vertical arrival angle of radio waves, A simulation using a three-dimensional model can be performed with less communication traffic regardless of the number of antenna elements. Also, the number of antenna elements can be expanded by adding hardware without changing the program.

  INDUSTRIAL APPLICABILITY The present invention is suitable for use in the development of a mobile communication system that performs wireless communication using an apparatus that uses a plurality of antenna elements due to space reproduction capability. Further, the present invention can reproduce regional characteristics and propagation environment at an arbitrary traveling speed, and is suitable for use in the development of new mobile communications.

The figure which shows the system configuration | structure containing the fading simulator which concerns on one embodiment of this invention The block diagram which shows the structure of the propagation model generation apparatus which concerns on the said embodiment The block diagram which shows the structure of the fading simulator which concerns on the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Propagation model generation apparatus 101 3D map data generation part 102 Propagation environment construction part 103 Channel impulse response acquisition part 104 Spatio-temporal profile generation part 105 Parameter calculation part 200 Fading simulator 201 Position information storage part 202 Phase calculation part 203 Fading circuit

Claims (2)

A fading simulator for simulating a propagation environment using parameters of a three-dimensional model generated by a propagation model generation device,
Position information storage means for storing the spatial position of the antenna element of the base station;
The reference phase, horizontal arrival angle, and vertical arrival angle parameters common to all antenna elements are input from the propagation model generation device, and the reference phase, horizontal arrival angle, vertical arrival angle parameters, and the Phase calculating means for calculating the phase of each antenna element from the spatial position of the antenna element;
Each parameter of received power and delay time for each antenna element is input from the propagation model generation device , and fading for generating a fading state of a propagation channel based on each parameter of the received power and delay time and the phase of each antenna element. A fading simulator comprising: a generating means; The propagation channel is determined using the three-dimensional map data, and the received power for each antenna element representing the propagation channel, the delay time, and the parameters of the reference phase, the horizontal arrival angle, and the vertical arrival angle common to all antenna elements A propagation model generation device for calculating
The reference phase, the horizontal angle of arrival, to calculate the phase of each antenna element from the spatial position of the respective parameters and the antenna element in the vertical direction angle of arrival, based on the received power, the each parameter of the delay time-phase of each antenna element And a fading simulator for generating a fading state of the propagation channel.

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