Evaluation method for 5G broadband signal coverage performance inside aircraft cabin

Abstract

The present invention discloses a method for evaluating the coverage performance of 5G broadband signals inside a cabin, and the steps are as follows: the first step is that the user provides a cabin internal structure design drawing and object material scene information, and specifies the location of the 5G signal access point, the communication bandwidth, the communication frequency, and the transmission power; the second step is to use different triangular facets to perform three-dimensional reconstruction of all regular and irregular scatterers in the scene according to the scene information provided by the user, and define the material information; the third step is to model the 5G broadband channel inside the cabin; the fourth step is to calculate the cabin broadband channel parameters based on the cabin scene reconstructed in the first and second steps; the fifth step is to evaluate the coverage performance of 5G broadband signals in the cabin. The present invention combines the cabin environment characteristics and the cabin broadband channel model to provide a method for evaluating the coverage performance of 5G signals in the cabin, and provides a basis for the layout reference of future 5G signal access points.

Description

Technical field:

[0001] The present invention relates to mobile communication channel modeling and simulation, in particular to modeling a 5G broadband communication channel inside a cabin and evaluating the coverage performance of the 5G broadband signal inside the cabin, and belongs to the field of wireless communications. Background technology:

[0002] 5G communication can provide higher speed, lower latency, more connections, faster mobile speed, stronger security and more flexible business deployment capabilities, thus supporting enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (uRLLC) and massive machine-type communication (mMTC) three major scenarios. At present, 2G / 3G base stations have been used in aircraft cabins in Europe and the United States, and there are no application cases in China. With the successful commercial use of 5G networks in China, air passengers are still unable to experience the technical advantages and conveniences brought by 5G, such as rich media messages, edge computing and other value-added telecommunications services. On the other hand, the demand for the integrated development of 5G and aviation is becoming more and more urgent. COMAC has clearly put forward the 5G development strategy for domestic large aircraft, and the entry of 5G into aircraft has become the basis for the expansion of 5G applications.

[0003] Using 5G broadband signals to control electromechanical equipment in the cabin, intelligently interact with user information, and share infrastructure in the cloud is of great significance for high-quality experiences such as passenger work and audio-visual entertainment, as well as intelligent control of cabin equipment. However, the development time of 5G communication technology is limited, and the corresponding supporting technologies such as channel modeling technology and signal coverage performance evaluation are not yet mature. In particular, there is no perfect solution for how to evaluate signal coverage in the cabin based on the propagation characteristics of 5G broadband signals, which has become a huge obstacle to the use of 5G on aircraft.

[0004] In order to achieve accurate and efficient practical application of wireless mobile communications in the cabin, it is crucial to observe the power distribution and understand the signal coverage. Good signal coverage can ensure the normal operation of wireless communications in the cabin environment with abundant obstructions and complex scattering types, and improve the communication quality of 5G broadband signals in the cabin.

[0005] At present, wireless coverage is generally divided into indoor wireless coverage and outdoor wireless coverage. With the development of communication and network technology, outdoor coverage has basically been seamless, and voice quality has been greatly improved, so the importance of achieving indoor signal coverage has become prominent. The indoor wireless signal coverage system mainly solves the communication and network quality problems in buildings, and also provides technical support for the optimization layout of wireless communications in the cabin in the future.

[0006] The size, placement, and transmission power of the electromechanical equipment in the cabin are the transmitting equipment for wireless mobile communications in the cabin. These indicators have a huge impact on the strength and accuracy of the 5G broadband signal received by the user. Therefore, after evaluating the coverage performance of the 5G broadband signal in the cabin, the signal transmission equipment in the cabin is optimized to better meet the communication needs of the signal in the cabin after improving the intelligence of the aviation equipment control. Unlike traditional narrowband communication systems, 5G communication systems will use a larger bandwidth to achieve high-speed data transmission. Its communication channel shows obvious frequency non-stationarity, and the composite influence of different frequency components in the bandwidth on the channel characteristics cannot be ignored. Existing methods realize channel modeling by decomposing the broadband channel into multiple sub-band channels. On the one hand, it is difficult to determine the number of sub-bands, and on the other hand, it greatly increases the complexity of channel reproduction. In addition, the interior of the cabin is a typical closed and shielded space with abundant scatterers. During the propagation of 5G signals, a large number of reflection and scattering effects will occur, and the channel multipath effect is more complicated, which brings challenges to the analysis of channel characteristics and signal coverage optimization. Therefore, it is necessary to build a real broadband channel model inside the cabin, and based on this, realize the coverage performance evaluation of 5G signals in the cabin, provide effective support for the implementation of 5G on aircraft, and thus improve the intelligence of aviation equipment control and user experience satisfaction. Summary of the invention:

[0007] The present invention provides a method for evaluating the performance of 5G broadband signal coverage inside the cabin in order to solve the problems existing in the above-mentioned prior art. The method takes into account the influence of different frequency components in the broadband channel on the channel parameters, constructs a model that can accurately reproduce the 5G broadband communication channel model in the cabin, and based on this, provides a performance evaluation method for 5G signal coverage in the cabin.

[0008] The technical solution adopted by the present invention is: a method for evaluating the 5G broadband signal coverage performance inside a cabin, the steps are as follows:

[0009] In the first step, the user provides the cabin internal structure design and object material scene information, and specifies the 5G signal access point location, communication bandwidth, communication frequency and transmission power;

[0010] The second step is to use different triangular facets to perform 3D reconstruction of all regular and irregular scatterers in the scene based on the scene information provided by the user, and define the material information;

[0011] The third step is to model the 5G broadband channel inside the cabin;

[0012] Step 4: Calculate the cabin broadband channel parameters based on the cabin scenes reconstructed in steps 1 and 2;

[0013] Step 5: Evaluate the 5G broadband signal coverage performance in the cabin.

[0014] Furthermore, the specific method of the third step is as follows:

[0015] 1) The broadband channel is regarded as a composite superposition of numerous impulse responses of channels at different frequencies within the bandwidth, and is modeled as

[0016]

[0017] Where N is the number of effective propagation paths, α(t; f′), ψ(t; f′) and τ n are the amplitude gain, path phase and delay of the nth propagation path respectively;

[0018] 2) Model the amplitude gain as a free space propagation model with a correction factor as follows:

[0019]

[0020] Where c is the speed of light, ξ n is the scene-dependent correction factor;

[0021] 3) The path phase is divided into two parts: initial phase and Doppler frequency for modeling. The method is as follows:

[0022]

[0023] where ψ0 is a random initial phase uniformly distributed in [0,2π), v MT / MR (t) is the moving speed of the transmitting and receiving ends, is the spherical unit vector of the transmitting and receiving ends. If there is no moving scatterer in the cabin, the phase is simplified and modeled as a fixed phase as follows:

[0024] ψ n (t;f′)=ψ0 (23)

[0025] 4) Substitute the amplitude gain and phase expressions into the formula (20) to obtain the broadband channel model in the cabin:

[0026]

[0027] in, Ei(·) is the exponential integral function.

[0028] Furthermore, the specific method of the fourth step is as follows:

[0029] 1) Assume that the equation of the surface where reflection occurs is z = f(x, y), L tx =(x tx ,y tx ,z tx ) represents the 5G signal access point location vector, L rx =(x rx,y rx ,z rx ) represents the position vector of the receiving end. The transmitted signal is reflected from a point on the surface to the receiving end. The distance D from the transmitting end signal to the reflection point is R,Tx , the distance D from the reflection point to the receiving end signal R,Rx , the distance D from the transmitter to the receiver Tx,Rx They can be expressed as

[0030]

[0031]

[0032] D Tx,Rx =||L tx -L rx || (27)

[0033] Among them, L Sn (t) represents the nth reflection point Sn The real-time position vector of

[0034] According to Fermat's theorem, the optical path s = D R,Tx +D R,Rx To obtain the position of the reflection point R (x, y, z), the calculation formula is

[0035]

[0036] Assuming that the reflection plane equation is z = 0, the nth reflection point S can be calculated according to equation (27): n The coordinates of

[0037]

[0038] 1) Calculate the path propagation delay of the direct path and the non-direct path:

[0039]

[0040] 3) Calculate the azimuth and elevation angles of the departure angles of the direct and non-direct paths:

[0041]

[0042]

[0043]

[0044]

[0045] in, and They respectively represent the x-axis component, y-axis component and z-axis component of the direct departure path vector in the transmitter coordinate system. Similarly, the azimuth and elevation angles of the arrival angle are calculated.

[0046] Furthermore, the specific method of the fifth step is as follows:

[0047] 1) Arrange 5G signal access points according to user settings, and evenly distribute M user terminals in the passenger seat area;

[0048] 2) Use the channel model of step 3 formula (24) to determine the large-scale path loss between the transmitter and receiver as follows:

[0049]

[0050] Among them, P l,m represents the path loss between the lth transmitter and the mth receiver;

[0051] 3) Calculate the received signal strength at different receiving ends and the bit error rate of the multipath fading channel as follows:

[0052]

[0053]

[0054] Among them, P o is the transmit power specified by the user, c i , i and ω i is the unknown coefficient, N T is an order greater than or equal to 7;

[0055] 4) According to the receiving power and bit error rate of different receiving ends, the comprehensive evaluation index of the signal coverage performance at the current 5G access point location is weighted and calculated, and the method is as follows:

[0056]

[0057] Among them, δ1 and δ2 are the coefficients of the received signal strength and the system bit error rate weight respectively. When the optimization index reaches the minimum, it proves that the signal receiving power is large and the system bit error rate is small, which can prove that the wireless communication performance in the cabin is good and the actual channel parameters are calculated.

[0058] The present invention has the following beneficial effects:

[0059] (1) The present invention proposes a broadband channel model that takes into account continuous frequency domain response for 5G broadband signals inside the cabin, which can accurately reflect the composite influence of each frequency point in the broadband on the channel characteristics.

[0060] (2) A 5G signal coverage performance evaluation method in the cabin is proposed based on the cabin environment characteristics and the cabin broadband channel model, providing a basis for the layout reference of future 5G signal access points. Description of the drawings:

[0061] Figure 1 This is a design drawing of the interior structure of the cabin.

[0062] Figure 2 This is the layout diagram of the transceiver inside the cabin.

[0063] Figure 3 This is the distribution diagram of cabin channel receiving power.

[0064] Figure 4 This is the cabin channel receiving bit error rate diagram. Specific implementation method:

[0065] The present invention will be further described below in conjunction with the accompanying drawings.

[0066] The present invention constructs a model that can accurately reproduce the 5G broadband communication channel model in the cabin, and based on this, provides a method for evaluating the coverage performance of 5G signals in the cabin, including the following steps:

[0067] In the first step, the user provides the cabin internal structure design and object material information, and specifies the location of the 5G signal access point at L tx =(x tx ,y tx ,z tx )=(-0.04,10.55,2.00), the communication bandwidth is 500MHz, the communication frequency is 1GHz and the transmission power is 0dB, etc.; considering the symmetry of the uplink and downlink channels, this implementation case takes the downlink as an example, and therefore determines the 5G signal transmitting end.

[0068] In the second step, based on the scene information provided by the user, all regular and irregular scatterers in the scene are simplified and reconstructed in three dimensions using different triangular face elements and Markov processes through three-dimensional modeling software, and material information is defined. This implementation case uses the EVA Air B777-300ER aircraft. The dimensions and material information of elements such as the overall cabin structure, cabin interior walls, doors and windows, seats, luggage racks, toilets, and cabin passages are considered during the three-dimensional reconstruction, and a user receiving terminal is arranged at each seat, with a total of 45.

[0069] The third step is to model the 5G broadband channel inside the cabin. The specific method is as follows:

[0070] 1) The broadband channel is regarded as a composite superposition of numerous impulse responses of channels at different frequencies within the bandwidth, which can be modeled as

[0071]

[0072] Where N is the number of effective propagation paths, α(t; f′), ψ(t; f′) and τ n are the amplitude gain, path phase and delay of the nth propagation path respectively.

[0073] 2) Model the amplitude gain as a free space propagation model with a correction factor as follows:

[0074]

[0075] Where c is the speed of light, ξ n is the scene-dependent correction factor.

[0076] 3) The path phase is divided into two parts: initial phase and Doppler frequency for modeling. The method is as follows:

[0077]

[0078] where ψ0 is a random initial phase uniformly distributed in [0,2π), v MT / MR (t) is the moving speed of the transmitting and receiving ends, is the spherical unit vector of the transmitting and receiving ends. If there is no moving scatterer in the cabin, the phase can be simplified and modeled as a fixed phase as follows:

[0079] ψ n (t; f′) = ψ0 (42);

[0080] 4) Substitute the amplitude gain and phase expressions into the formula (1) to obtain the broadband channel model in the cabin:

[0081]

[0082] in, Ei(·) is the exponential integral function.

[0083] Step 4: Based on the cabin scene reconstructed in steps 1 and 2, calculate the cabin broadband channel parameters. The method is as follows:

[0084] 1) Assume that the equation of the surface where reflection occurs is z = f(x, y), L tx =(x tx ,y tx ,z tx ) represents the 5G signal access point location vector, L rx =(x rx ,y rx ,z rx ) represents the position vector of the receiving end. The transmitted signal is reflected from a point on the surface to the receiving end. The distance D from the transmitting end signal to the reflection point is R,Tx, the distance D from the reflection point to the receiving end signal R,Rx , the distance D from the transmitter to the receiver Tx,Rx They can be expressed as

[0085]

[0086]

[0087] D Tx,Rx =||L tx -L rx (46)

[0088] in, Indicates the nth reflection point Sn The real-time position vector.

[0089] According to Fermat's theorem, the optical path s = D R,Tx +D R,Rx To obtain the position of the reflection point R (x, y, z), the calculation formula is

[0090]

[0091] Assuming that the reflection plane equation is z = 0, the nth reflection point S can be calculated according to equation (9): n The coordinates of

[0092]

[0093] We select odd-numbered user receiving ends and take one reflection as an example (if there is no one reflection, the last reflection shall prevail, among which No. 9, No. 15, and No. 17 all select the last reflection of three reflections), listed in the following table:

[0094] Table 1 Simulation parameters

[0095]

[0096] 2) Calculate the path propagation delay of the direct path and the non-direct path:

[0097]

[0098] 3) Calculate the azimuth and elevation angles of the departure angles of the direct and non-direct paths:

[0099]

[0100]

[0101]

[0102]

[0103] in, and They represent the x-axis component, y-axis component and z-axis component of the direct departure path (or indirect departure path) vector in the transmitting end coordinate system. Similarly, the azimuth and elevation angles of the arrival angle can be calculated. Table 2 gives the odd-numbered user receiving end parameters.

[0104] Table 2 Simulation parameters

[0105]

[0106] Step 5: Evaluate the 5G broadband signal coverage performance in the cabin. The method is as follows:

[0107] 1) Arrange 5G signal access points according to user settings, and evenly distribute M user terminals in the passenger seat area.

[0108] 2) Use the channel model in step 3 to determine the large-scale path loss between the transmitter and receiver as follows:

[0109]

[0110] Among them, P l,m Represents the path loss between the lth transmitter and the mth receiver.

[0111] 3) Calculate the received signal strength at different receiving ends and the bit error rate of the multipath fading channel as follows:

[0112]

[0113]

[0114] Among them, P o is the transmit power specified by the user, c i , i and ω i is the coefficient to be determined, NT is an order greater than or equal to 7.

[0115] 4) According to the receiving power and bit error rate of different receiving ends, the comprehensive evaluation index of the signal coverage performance at the current 5G access point location is weighted and calculated, and the method is as follows:

[0116]

[0117] Among them, δ1 and δ2 are the coefficients of the received signal strength and the system bit error rate weight respectively. When the optimization index reaches the minimum, it proves that the signal received power is large and the system bit error rate is small, which can prove that the wireless communication performance in the cabin is good. The actual channel parameters are calculated, as shown in Table 3.

[0118] Table 3 Simulation parameters

[0119]

[0120]

[0121] The following will select transmitters at five different locations for data analogy to measure the impact of transmitter signals at different locations on the performance of wireless signal propagation. The signal reception strength and system bit error rate at the transmitter are used as the judgment indicators. Combined with formula (57), δ1=0.8, δ2=0.2 are taken to obtain the antenna optimization index. The larger the index, the greater the signal reception strength, that is, the smaller the signal power loss. At the same time, the smaller the system bit error rate, the higher the data transmission quality. Therefore, it is further verified that the performance of the transmitter position given by the user is better, and the coverage performance evaluation in the cabin is good. The results are shown in Table 4.

[0122] Table 4 Simulation parameters

[0123]

[0124] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for evaluating the coverage performance of 5G broadband signals in a cabin, characterized in that: Here are the steps: In the first step, the user provides the cabin internal structure design and object material scene information, and specifies the 5G signal access point location, communication bandwidth, communication frequency and transmission power; The second step is to use different triangular facets to perform 3D reconstruction of all regular and irregular scatterers in the scene based on the scene information provided by the user, and define the material information; The third step is to model the 5G broadband channel inside the cabin; Step 4: Calculate the cabin broadband channel parameters based on the cabin scenes reconstructed in steps 1 and 2; Step 5: Evaluation of 5G broadband signal coverage performance in the cabin; The specific method of the third step is as follows: 1) The broadband channel is regarded as a composite superposition of numerous impulse responses of channels at different frequencies within the bandwidth, and is modeled as Where N is the number of effective propagation paths, α(t; f′), ψ(t; f′) and τ n are the amplitude gain, path phase and delay of the nth propagation path respectively; 2) Model the amplitude gain as a free space propagation model with a correction factor as follows: Where c is the speed of light, ξ n is the scene-dependent correction factor; 3) The path phase is divided into two parts: initial phase and Doppler frequency for modeling. The method is as follows: Where ψ0 is a random initial phase uniformly distributed in [0,2π), v MT / MR (t) is the moving speed of the transmitting and receiving ends, r n MT / MR (t) is the spherical unit vector of the transmitting and receiving ends. If there is no moving scatterer in the cabin, the phase is simplified and modeled as a fixed phase as follows: ψ n (t;f′)=ψ0 (4) 4) Substitute the amplitude gain and phase expressions into the formula (1) to obtain the broadband channel model in the cabin: in, Ei(·) is the exponential integral function; The specific method of the fourth step is as follows: 1) Assume that the equation of the surface where reflection occurs is z = f(x, y), L tx =(x tx ,y tx ,z tx ) represents the 5G signal access point location vector, L rx =(x rx ,y rx ,z rx ) represents the position vector of the receiving end. The transmitted signal is reflected from a point on the surface to the receiving end. The distance D from the transmitting end signal to the reflection point is R,Tx , the distance D from the reflection point to the receiving end signal R,Rx , the distance D from the transmitter to the receiver Tx,Rx They can be expressed as D Tx,Rx =||L tx -L rx || (8) in, Indicates the nth reflection point S n The real-time position vector of According to Fermat's theorem, the optical path s = D R,Tx +D R,Rx To obtain the position of the reflection point R (x, y, z), the calculation formula is Assuming that the reflection plane equation is z = 0, the nth reflection point S can be calculated according to equation (9): n The coordinates of 2) Calculate the path propagation delay of the direct path and the non-direct path: 3) Calculate the azimuth and elevation angles of the departure angles of the direct and non-direct paths: in, and They respectively represent the x-axis component, y-axis component and z-axis component of the direct departure path vector in the transmitting end coordinate system; The specific method of the fifth step is as follows: 1) Arrange 5G signal access points according to user settings, and evenly distribute M user terminals in the passenger seat area; 2) Determine the large-scale path loss between the transmitter and receiver using the channel model of formula (5) in the third step as follows: Among them, P l,m represents the path loss between the lth transmitter and the mth receiver; 3) Calculate the received signal strength at different receiving ends and the bit error rate of the multipath fading channel as follows: Among them, P o is the transmit power specified by the user, c i , i and ω i is the coefficient to be determined, NT is an order greater than or equal to 7; 4) According to the receiving power and bit error rate of different receiving ends, the comprehensive evaluation index of the signal coverage performance at the current 5G access point location is weighted and calculated, and the method is as follows: Among them, δ1 and δ2 are the coefficients of the received signal strength and the system bit error rate weight respectively. When the optimization index reaches the minimum, it proves that the signal receiving power is large and the system bit error rate is small, which can prove that the wireless communication performance in the cabin is good and the actual channel parameters are calculated.

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