Channel quantization table construction method, indoor visible light communication system and electronic equipment

Abstract

The present application provides a channel quantization table construction method, an indoor visible light communication system and an electronic device, wherein the channel quantization table construction method comprises: dividing the receiving plane into N sub-areas; quantizing the actual channel gain values ​​of each point in the N sub-areas into the same channel gain value according to a preset rule; and constructing a channel quantization table of an indoor visible light communication system according to the N sub-areas and the quantized gain values ​​corresponding to each sub-area. The technical solution provided by the present application is that the transmitting end can quickly obtain the channel information between the user and each light source through table lookup and simple calculation based on the location information fed back by the terminal and the stored light source information, thereby reducing the computational complexity of channel information acquisition.

Description

Technical Field

[0001] The present application relates to the field of broadcast communication technology, and in particular to a channel quantization table construction method, an indoor visible light communication system and an electronic device. Background Art

[0002] Indoor Visible Light Communication (VLC) is a short-distance wireless transmission system that uses light emitting diodes (LEDs) as optical signal transmission sources and light waves as carriers. Similar to radio frequency (RF) wireless communication systems, the transmitter of indoor VLC systems also needs to rely on channel information to assist in key operations such as resource allocation, user scheduling, and transmitter preprocessing in order to improve transmission performance.

[0003] In traditional RF communication systems, the way the transmitter obtains channel information usually relies on the terminal's estimation and feedback of the channel information. However, indoor VLC systems are significantly different from RF systems due to their unique physical properties and transmission mechanisms. VLC systems use visible light waves as carriers for transmitting signals, and their channel characteristics are significantly different from RF wireless communications. In particular, when the location of the optical signal transmission source is determined, if the reflection path, which accounts for a small proportion (about 5%), is ignored and only the direct path is considered, the VLC channel will be mainly determined by factors such as the location of the transmitting light source, the location and posture of the receiving terminal, etc.

[0004] In order to avoid the problem of excessive feedback overhead caused by the terminal separately feeding back the channel information between it and multiple light sources, indoor visible light communication can also use indirect channel information of position and attitude information feedback to obtain channel information. Specifically, the receiving terminal feeds back its own position information and attitude information to the base station through the uplink. The base station then summarizes this information and transmits it to the central controller. The central controller combines the stored source location information and the received terminal location information and attitude information to calculate the channel information of the corresponding link. This method effectively avoids the huge feedback overhead problem caused by the need for the terminal to separately feed back the channel information between it and multiple light sources in the traditional way. However, the central controller must calculate the channel characteristics of each communication link based on the collected terminal location information, terminal attitude information, and stored light source signal transmission source location information. This process significantly increases the demand for computing resources when the number of terminal nodes is large, which should not be underestimated. Summary of the invention

[0005] Therefore, the present application provides a channel quantization table construction method, an indoor visible light communication system and an electronic device, which further reduces the amount of calculation required for acquiring channel information at the transmitting end by proposing a channel quantization information acquisition method based on a table lookup method that combines offline and online methods for devices with a fixed vertical posture. First, according to the relationship between position and channel, a channel quantization table is designed offline before network construction, and the table is stored in a central controller; then, during the network operation phase, the quantitative channel information can be obtained through simple calculations and table lookup mapping based on the terminal position information fed back in real time, further reducing the computational complexity of acquiring channel information at the transmitting end.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, a method for constructing a channel quantization table is provided, the method comprising:

[0008] Divide the receiving plane into N sub-areas;

[0009] quantizing the actual channel gain value of each point in the N sub-areas into the same channel gain value according to a preset rule;

[0010] A channel quantization table for an indoor visible light communication system is constructed according to the divided N sub-areas and the quantization gain value corresponding to each of the sub-areas.

[0011] Optionally, dividing the receiving plane into N sub-areas includes:

[0012] The receiving plane is divided into the N sub-areas at equal intervals, or the receiving plane is divided into the N sub-areas at approximately equal quantization errors.

[0013] Optionally, dividing the receiving plane into N sub-areas at equal intervals includes:

[0014] The receiving plane is divided into a plurality of concentric rings at equal intervals, and each concentric ring is one of the sub-areas.

[0015] Optionally, quantizing the actual channel gain values ​​of each point in the N sub-areas into the same channel gain value according to a preset rule includes:

[0016] The quantized channel gain value of the sub-area is obtained according to the maximum radius of the receiving plane and the distance from the outer wall to the center of the sub-area.

[0017] Optionally, dividing the receiving plane into N sub-areas with approximately equal quantization errors includes:

[0018] Dividing the receiving plane into two first sub-areas with equal quantization errors;

[0019] Dividing the two first sub-regions into two second sub-regions with equal quantization errors;

[0020] Repeat the above division steps until the division is completed.

[0021] Optionally, the number of N sub-regions is a power of 2.

[0022] Optionally, the method further includes:

[0023] According to the channel gain quantization errors of the two sub-regions with equal quantization errors, obtaining the channel gain value at the boundary of the two sub-regions;

[0024] A dividing point between the two sub-areas is obtained according to the channel gain value at the dividing point.

[0025] Optionally, constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-regions and the quantization gain value corresponding to each of the sub-regions includes:

[0026] Obtaining normalized boundary values ​​of each sub-region and quantized channel gain values;

[0027] The boundary value interval after normalization of the height in the receiving plane is associated with the quantized channel gain value corresponding to each of the sub-areas to construct a quantized channel gain table.

[0028] In the second aspect, a terminal, a base station and a central controller; the terminal feeds back location information to the base station via an uplink; the base station summarizes the received location information to the central controller; the central controller uses a channel quantization table as described in any one of the first aspects to obtain the channel information of the terminal based on the received location information.

[0029] In a third aspect, an electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the channel quantization table construction method as described in any one of the first aspects.

[0030] In a fourth aspect, a non-transitory computer-readable storage medium is provided, characterized in that the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute any one of the channel quantization table construction methods described in the first aspect.

[0031] An embodiment of the present application provides a method for constructing a channel quantization table, which includes: dividing a receiving plane into N sub-areas; quantizing the actual channel gain values ​​of each point in the N sub-areas into the same channel gain value according to a preset rule; and constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-areas and the quantized gain value corresponding to each sub-area, thereby further reducing the computational complexity of acquiring channel information at the transmitting end. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a visible light transmission link provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the distribution of channel gain on a receiving plane provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the effect of the horizontal distance r on the LOS channel gain provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram of a flow chart of a channel quantization method for an indoor visible light communication system provided in an embodiment of the present application;

[0036] Figure 5 A schematic diagram of an example of sub-area division of a receiving plane provided in an embodiment of the present application;

[0037] Figure 6 It is shown that N=8, , Schematic diagram of the quantitative RMSE distribution curve of each sub-region under the EID scheme;

[0038] Figure 7 A schematic diagram of equal error division of a receiving plane provided in an embodiment of the present application;

[0039] Figure 8 It is shown that N=8, , Schematic diagram of the quantitative RMSE distribution curve of each sub-region under the EED scheme;

[0040] Figure 9A-9C A schematic diagram of the relative mean square error comparison difference of each sub-region under two sub-region division methods when N=8, 16, and 32 provided in an embodiment of the present application;

[0041] Fig.10 A schematic diagram of average RMSE under different numbers of sub-regions provided in an embodiment of the present application;

[0042] Fig.11 A schematic diagram of an indoor visible light communication system model provided in an embodiment of the present application;

[0043] Fig.12 A schematic diagram of a method that can implement an embodiment of the present invention or a device that can implement an embodiment of the present invention is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0044] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of the well-known business call service processes are omitted to prevent unnecessary details from obstructing the description of the present application.

[0045] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "said", "above", and "the" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0046] In RF wireless communication systems, the method of estimating channel information by the terminal and transmitting it to the transmitter through a feedback mechanism is usually adopted, so that the transmitter can accurately obtain channel state information. However, the VLC system has characteristics that are significantly different from the RF wireless communication system. VLC uses visible light waves as the carrier for signal transmission, and its channel characteristics are very different from RF wireless communication. When the position of the optical signal transmitting source of the VLC system is determined, if the reflection path accounting for about 5% is ignored and the influence of the direct path is mainly considered, then the channel characteristics will be jointly determined by information such as the position of the light source of the transmitting signal, the position of the receiving terminal, and the posture of the terminal.

[0047] In view of this characteristic of the VLC system, the traditional channel information acquisition method is not applicable. Therefore, it is necessary to provide a new channel information acquisition mechanism. Considering that indoor access terminals include not only mobile and variable posture devices, but also mobile but fixed vertically upward devices. For devices with fixed vertically upward posture, their channel information is completely determined by the position, and the relationship between the position and the channel satisfies the known expression. Therefore, for devices with fixed vertically upward posture, a channel quantization information acquisition method based on table lookup method combining offline and online is proposed to further reduce the amount of calculation required for channel information acquisition at the transmitter. First, according to the relationship between position and channel, the channel quantization table is designed offline before network construction, and the table is stored in the central controller; then, during the network operation stage, the quantitative channel information can be obtained through simple calculation and table lookup mapping based on the real-time feedback of the terminal position information.

[0048] An embodiment of the present application proposes a channel quantization table construction method, which includes: dividing a receiving plane into N sub-areas; quantizing the actual channel gain values ​​of each point in the N sub-areas to the same channel gain value according to a preset rule; and constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-areas and the quantized gain value corresponding to each sub-area, thereby further reducing the computational complexity of acquiring channel information at the transmitting end.

[0049] The following first introduces the visible light communication system, see Figure 1 . Figure 1 A schematic diagram of a visible light transmission link provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, assuming that the LED follows the Lambertian radiation model and only considers the direct (Line Of Sight, LOS) path, the DC channel gain between the lamp and the receiver can be expressed as formula (1):

[0050] (1)

[0051] in, is the effective area of ​​the photodetector, is the Euclidean distance between the light source and the receiver, and are the incident angle and irradiance angle, is the Langbo radiation coefficient of the light source. To receive the field of view, is the Lambert radiation series, which is related to the half-power angle of the LED light. related.

[0052] In the IoT scenario, non-handheld terminal users are usually placed vertically to the light source. In this case, the incident angle and irradiation angle are the same. and The value of can be expressed as: So the DC channel gain between the two can be simplified to formula (2):

[0053] (2)

[0054] in , it can be seen from formula (2) that the LOS channel gain actually depends on the vertical distance between the LED and the user and horizontal distance .

[0055] The following is an introduction to the channel gain distribution on the receiving plane, see Figure 2 . Figure 2 A schematic diagram of the distribution of channel gain on a receiving plane provided in an embodiment of the present application. Figure 2As shown, set the LED half-power angle (degrees), effective receiving area of ​​the receiver (square centimeters), receiver field of view . Figure 2 Shows the distance from the emitting surface where the LED is located Channel gain distribution on the receiving plane (m). Figure 2 It can be seen that at a given receiving plane height, the channel gain distribution mainly depends on the horizontal distance between the user and the LED. To present this trend more intuitively, see Figure 3 . Figure 3 A schematic diagram of the effect of the horizontal distance r on the LOS channel gain provided in an embodiment of the present application. Figure 3 The figure shows the variation trend of channel gain with horizontal distance. Figure 3 As shown, with The increase of decreases, and as The further increase of The rate of decrease gradually slows down.

[0056] From the above, it can be seen that in an indoor visible light communication IoT system, once the relevant physical parameters of the access point and the receiver are determined, the channel gain of the user terminal in a fixed direction (vertical direction for example) has a strong correlation with the user position. The following introduces a method for quantifying the channel using this correlation, see Figure 4 . Figure 4 A schematic diagram of a channel quantization method for an indoor visible light communication system provided in an embodiment of the present application. Figure 4 The channel quantization method shown comprises the following steps:

[0057] S401: Divide the receiving plane into N sub-areas.

[0058] Specifically, the channel gain of a user terminal in a fixed direction is strongly correlated with the user position in a visible light communication system to perform channel quantization. First, the receiving plane at the same height is divided into multiple concentric rings at equal intervals, each concentric ring represents a sub-area, and the channel gain of the receiving point in each sub-area is quantized to the same value. Figure 5 , Figure 5 This is a schematic diagram of an example of sub-area division of a receiving plane provided in an embodiment of the present application. Figure 5 As shown, the receiving plane is divided into N sub-areas, and each sub-area is numbered in sequence. The distance from the outer ring to the center of the nth (n=1, 2, ······, N) sub-area is denoted by Indicates that N is a positive integer greater than or equal to 2. The channel gains of all receiving points in the same sub-area are quantized to the same value. This method is conducive to converting the continuous two-dimensional channel distribution of the entire receiving plane into a one-dimensional discrete distribution. At this time, the division of sub-areas and the selection of quantization values ​​in each sub-area are the key factors affecting the channel quantization error.

[0059] Since the relative mean square error of the equal interval division method is different in different sub-areas, this will lead to unfair communication for users in different indoor areas. In order to solve this problem, the embodiment of the present application proposes a regional division method that ensures that the relative mean square error of quantization in each sub-area is approximately equal, referred to as the equal error division (Equal Error Division, EED) method, see Figure 6 . Figure 6 A schematic diagram of receiving plane equal error division provided in an embodiment of the present application. Figure 6 The equal-interval division shown includes: firstly dividing the entire area into two sub-areas (first sub-areas) with equal intervals, obtaining the channel quantization values ​​of the two first sub-areas according to a preset quantization criterion, the quantization errors of the two first sub-areas are the same, and then obtaining the channel gain value at the boundary of the two first sub-areas, and further obtaining the two first sub-area dividing points to divide the receiving area into two.

[0060] According to the above division method, the two first sub-regions that have been divided are divided again, so that the two first sub-regions are divided into two second sub-regions with equal relative quantization errors. Finally, the receiving area is divided into N sub-areas with approximately equal relative quantization errors. Due to the limitation of the binary division step, the number of sub-areas N that can be selected in this sub-area division scheme needs to be subject to the condition The constraints, where This division method makes the errors of each area equal after division, which solves the problem of communication perception difference caused by error change in different areas when the equal interval division method is used.

[0061] It should be noted that the preset quantization criterion in the embodiment of the present application can be the minimum relative mean square error between the actual channel gain value and the quantized channel gain value, or the mean of the actual channel gain value in the divided area, or the maximum value of the actual channel gain value in the divided area, or the minimum value of the actual channel gain value in the divided area, or any set value, and the channel gain value of the sub-area is quantized to the same value according to the preset quantization criterion. In the embodiment of the present application, the minimum value of the relative mean square error between the actual channel gain value and the quantized channel gain value is used as the quantization criterion, but the embodiment of the present application does not specifically limit the quantization criterion.

[0062] S402: quantizing the actual channel gain value of each point in the N sub-areas into the same channel gain value according to a preset rule.

[0063] Specifically, when the channel gains in the sub-regions are quantized to the same value, the selection of the quantization value is a key factor affecting the quantization error. The embodiment of the present application provides a relative mean square error (RMSE) as a measure for defining the quantization error, but does not impose specific restrictions on the quantization criteria. The larger the RMSE, the larger the quantization error. The relative mean square error of the nth sub-region is defined as formula (3):

[0064] (3)

[0065] in, is the actual channel gain value of the receiving point, is the quantized channel gain value of the sub-region, and are the maximum and minimum values ​​of the actual channel gain of the sub-area, respectively, and they correspond to the receiving points at the outer boundary and inner boundary of the sub-area, respectively. In the sub-area Assuming that users are uniformly and randomly distributed on the receiving plane, the distance between each receiving point in the sub-area and the projection point of the access point on the receiving plane is The probability density function of is formula (4):

[0066] (4);

[0067] From formula (2), we can see that yes Therefore, according to the knowledge of the distribution of random variable functions, we can get The probability density function of is formula (5):

[0068] (5)

[0069] Compare RMSE with Differentiate and solve To derive the optimal , optimal As shown in formula (6):

[0070] (6)

[0071] Get the best Then this optimal As the quantized channel gain value of the sub-area, that is, the channel gain values ​​of all receiving points in this sub-area are set to .

[0072] In the embodiment of the present application, m=1 is used for schematic illustration, where m is the Lambertian radiation coefficient of the light source, and the embodiment of the present application does not impose any specific restrictions on the value of m. Substituting m=1 into formula (6) can yield formula (7):

[0073] (7)

[0074] Substituting formula (7) into formula (3), the relative mean square error of the sub-region can be obtained as shown in formula (8):

[0075] (8)

[0076] As shown in formula (8), the quantized RMSE of the sub-region is determined by the channel values ​​at both ends of the sub-region boundary: and On the other hand, the channel value at the boundary depends on the number and method of sub-region division.

[0077] The following are Figure 5 The equal interval division (EID) method shown in the figure introduces the process of quantizing the channel gains in the sub-regions to the same value after dividing the channel sub-regions.

[0078] like Figure 5 As shown, the receiving plane at a given height is divided into N concentric circles with equal intervals. The distance from the outer wall of the sub-region ring to the center is ,in is the maximum radius of the receiving plane, which is determined by the height of the receiving plane and the field of view of the receiving plane, satisfying Although the receiving areas corresponding to receiving planes at different heights have different sizes, the boundary determination criteria of the sub-areas on the receiving plane are the same under the equally spaced EID scheme.

[0079] Will and Substituting into formula (7), we can get The quantization channel gain value of each sub-region is given by formula (9):

[0080] (9)

[0081] According to The boundary value of the sub-region can determine the upper and lower bounds of the channel gain of the sub-region. Substituting formula (8) to derive the quantitative RMSE under the EID method is formula (10):

[0082] (10)

[0083] From formula (10), we can see that for a given sub-region division method, the RMSE of sub-region quantization is not affected by the height of the receiving plane. Instead, it depends on the receiver field of view angle. and the total number of subregions N.

[0084] Preferably, the embodiment of the present application also provides the quantitative RMSE distribution curve of each sub-region under the EID scheme, see Figure 6 . Figure 6 It is shown that N=8, , Schematic diagram of the quantitative RMSE distribution curve of each sub-region under the EID scheme.

[0085] The present application embodiment also analyzes the quantization relative mean square error of different sub-regions, see Table 1, which shows that N=8, ,When the receiving area is equally divided into 8 sub-areas, the quantized relative mean square error of each sub-area,It should be noted that Table 1 retains two decimal places.

[0086] Table 1

[0087]

[0088] In Table 1, the smaller the sub-region number is, the closer it is to the center of the receiving plane. As shown in Table 1, the RMSE distribution of different sub-regions is uneven, and the sub-region closer to the center of the receiving plane has a smaller relative mean square error.

[0089] Since the relative mean square error of the equal interval division method is different in different sub-areas, this will lead to unfair communication for users in different indoor areas. In order to solve this problem, the embodiment of the present application proposes a regional division method that tries to ensure that the relative mean square error of quantization in each sub-area is approximately equal, referred to as the equal error division (Equal Error Division, EED) method, see Figure 7 . Figure 7 A schematic diagram of receiving plane equal error division provided in an embodiment of the present application. Figure 7 The equal error partitioning shown includes the following steps:

[0090] Divide the entire area into two sub-areas.

[0091] Specifically, if the channel gain value at the boundary of the two sub-regions is According to the channel quantization criteria given above, the channel quantization values ​​of these two sub-regions can be obtained, which are respectively recorded as and According to formula (3), the RMSE of these two sub-areas are shown in formula (11) and formula (12) respectively:

[0092] (11)

[0093] (12)

[0094] in, is the channel gain value at the center of the circle where the receiving plane is located, is the channel gain value at the outer boundary of the receiving plane. Let The channel gain value at the area division boundary that satisfies the relative mean square error of the two sub-areas can be obtained. for: So we can use The location is the dividing point that divides the receiving area into two.

[0095] Repeat the above division steps to divide the two sub-regions into two sub-regions, so that the two sub-regions divided once are divided into two sub-regions with equal relative quantization errors. Finally, the receiving area is divided into N sub-areas with approximately equal relative quantization errors. Due to the limitation of the binary division step, the number of sub-areas N that can be selected in this sub-area division scheme needs to be subject to the condition The constraints, where This division method makes the errors of each sub-area approximately equal after division, which solves the problem of communication perception difference caused by error change in different areas when the equal interval division method is used.

[0096] When the number of equally spaced regions is N, The boundary values ​​of each sub-region can be obtained as shown in formula (13):

[0097] (13).

[0098] Substituting the boundary value in formula (13) into formula (2), we can get the distance from the boundary to the center of the circle: Formula (14):

[0099] (14).

[0100] Substituting formula (13) into formula (7) yields the following equation: The quantization channel gain value of each sub-region is given by formula (15):

[0101] (15).

[0102] Substituting formula (13) into formula (8) yields the following equation: The quantitative RMSE of each sub-region is given by formula (16):

[0103] (16).

[0104] As shown in formula (16), like the equal interval division, the RMSE of the sub-region quantization in the equal error division is also not affected by the height of the receiving plane.

[0105] Preferably, the embodiment of the present application also provides the quantitative RMSE distribution curve of each sub-region under the EED scheme, see Figure 8 . Figure 8 It is shown that N=8, , Schematic diagram of the quantitative RMSE distribution curve of each sub-region under the EED scheme.

[0106] The embodiment of the present application analyzes the relative mean square errors of quantization of different sub-regions in the equal error partitioning method, see Table 2, which shows that N=8, , the relative mean square error of each sub-region is quantized when the receiving area is divided into 8 sub-regions with equal errors.

[0107] Table 2

[0108]

[0109] As shown in Table 2, the eight sub-regions divided by the equal error division scheme have achieved a high degree of consistency in relative errors. Although there are slight differences in the values, these differences are small enough to be ignored, thus achieving a regional division with approximately equal errors. The following analysis of the specific impact of the number of sub-regions on the relative mean square error is shown in Figure 9A-9C . Figure 9A-9C A schematic diagram of the comparison of relative mean square errors of sub-regions under two sub-region division methods when N=8, 16, and 32 provided in an embodiment of the present application.

[0110] like Figure 9A-9C As shown in the figure, the increase in the number of subregions does not change the distribution trend of the relative mean square error among subregions. Specifically, for the first small part of the subregion sequence, the error of the EID scheme is significantly lower than that of the EED scheme, while for the subregions with the following numbers, the EED scheme has an advantage. In addition, compared with the EID scheme, the fluctuation of the relative mean square error of the EED scheme among different subregions is almost negligible. Then, regardless of the partitioning scheme, the error within each subregion decreases significantly with the increase in the number of subregions. Figure 8 To further compare the performance of the two methods, Fig.10 A schematic diagram of average RMSE under different numbers of sub-regions provided in an embodiment of the present application. Fig.10 A comparison of the average RMSE of all sub-regions over a wider range of numbers of sub-regions is shown.

[0111] Fig.10It shows that RMSE does not decrease linearly with the increase in the number of sub-regions. When N increases from 4 to 8, the RMSE of EID decreases from 0.042 to 0.011, a decrease of 73.8%; the RMSE of EED decreases from 0.039 to 0.01, a decrease of 74.4%. When N increases from 8 to 16, the RMSE of EID decreases by 72.7%, from 0.011 to 0.003, and the RMSE of EED decreases by 75%, from 0.01 to 0.0025. When N continues to increase from 16 to 32, the RMSE of EID decreases by 75% from 0.0028 to 0.0007, and the RMSE of EED decreases by 76% from 0.0025 to 0.0006.

[0112] like Fig.10 The results show that the average RMSE of the two sub-region division schemes are basically similar. Considering that the average RMSE of 0.0025 is sufficient to meet the requirements of most applications, this application tends to recommend the selection of a division scheme of N=16. However, in actual implementation, especially in application scenarios that are highly sensitive to channel errors, a higher number of sub-region divisions can be considered to further reduce the error. The embodiment of the present application does not specifically limit the number of divided sub-regions.

[0113] S403: Constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-regions and the quantization gain value corresponding to each sub-region.

[0114] Specifically, the positions of LEDs in the room are usually fixed and their parameters are known. Once the number of sub-area divisions, the division method and the quantization criteria are determined, the channel quantization gain table of the corresponding access point can be derived based on the LED parameters. Since the channel is determined by the relative position between the user and the access point, the same quantization gain table can be applied to all access points. This section takes the EED scheme as an example to give the design of a table lookup channel information acquisition method based on channel quantization.

[0115] First, according to formula (14) and formula (15), the normalized boundary values ​​of each region can be obtained: Formula (17) and the quantized channel gain value Formula (18):

[0116] (17).

[0117] (18).

[0118] in, and It is a parameter determined by the sub-area division method and is only related to the physical parameters of the access point and the field of view of the receiver.

[0119] Further, the boundary reference interval under the normalized height is associated with the quantization channel reference gain value corresponding to each interval to establish a quantization channel gain table. Referring to Table 3, for example, Table 3 shows the quantization channel gain of equal error partitioning when the number of sub-regions is 8.

[0120] Table 3

[0121]

[0122] When the height changes, it can be seen from formula (17) and formula (18) that we only need to use the parameter The normalized quantized channel gain table is , After processing, a quantized channel gain table that meets the current height can be obtained.

[0123] In summary, the method provided by the embodiment of the present application divides the receiving plane into different sub-areas, the channels in each sub-area are quantized to a unified value, and the channel quantization values ​​of all sub-areas are stored in a table to form a channel quantization table. The transmitting end can quickly obtain the channel information between the user and each light source through table lookup and simple calculation based on the location information fed back by the terminal and the stored light source information, thereby reducing the computational complexity of channel information acquisition.

[0124] In indoor scenarios, the access point is fixed, and the transmitter calculates the horizontal distance parameter between the user and each access point based on the location information fed back by the user and the location information of the known access points. and vertical distance parameters . Update the quantized channel gain table that meets the current user's needs, and then look up the table to obtain the quantized channel gain.

[0125] The above describes the method for constructing a channel quantization table for an indoor visible light communication system. The following describes an indoor visible light communication system. Fig.11 , Fig.11 A schematic diagram of an indoor visible light communication system model provided in an embodiment of the present application. Fig.11 The indoor visible light communication system 10 shown in FIG. 1 includes a central controller 101 and a signal transmission source 102. Fig.11In the embodiment shown, the indoor lighting LED can act as a signal generator 102, emitting a light signal carrying useful information while illuminating, and the LED light radiation close to the Lambertian luminous body satisfies the Lambertian radiation model. For the terminal with a fixed vertical posture, the initial channel quantization table is obtained according to the channel quantization table method provided in the above embodiment at the initial stage of indoor visible light communication network construction, and the channel quantization table is stored in the central controller 102. In the network operation stage, the central controller 102 can obtain the quantitative channel information through simple calculation and table lookup mapping based on the location information fed back by the terminal in real time, further reducing the amount of calculation required for the transmitter to obtain the channel information. It should be noted that the channel quantization table can be updated in real time.

[0126] In summary, an embodiment of the present application provides a channel quantization table construction method, which includes: dividing a receiving plane into N sub-areas; quantizing the actual channel gain value of each point in the N sub-areas to the same channel gain value according to a preset rule; constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-areas and the quantized gain value corresponding to each sub-area, further reducing the computational complexity of acquiring channel information at the transmitting end.

[0127] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0128] The present application also provides an electronic device, which includes:

[0129] at least one processor; and,

[0130] a memory communicatively connected to the at least one processor; wherein,

[0131] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for constructing a channel quantization table for an indoor visible light communication system of any of the aforementioned embodiments.

[0132] On the other hand, an embodiment of the present application also provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable the computer to execute the method for constructing a channel quantization table for an indoor visible light communication system described in any of the aforementioned embodiments.

[0133] An embodiment of the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the channel quantization table construction method of any of the aforementioned embodiments.

[0134] An embodiment of the present application further provides a computer program, which includes program instructions. When the program instructions are executed by a computer, the computer executes the method for constructing a channel quantization table for an indoor visible light communication system of any of the aforementioned embodiments.

[0135] Fig.12 A schematic diagram of a method or device for implementing an embodiment of the present application provided for an embodiment of the present application may include more or fewer devices than shown in the figure in some embodiments. In some embodiments, it can be implemented using a single or multiple devices. In some embodiments, it can be implemented using cloud or distributed devices.

[0136] like Fig.12 , the device 1000 includes a processor 1001, which can perform various appropriate operations and processes according to the program and / or data stored in the read-only memory (ROM) 1002 or the program and / or data loaded from the storage part 1008 to the random access memory (RAM) 1003. The processor 1001 can be a multi-core processor or include multiple processors. In some embodiments, the processor 1001 can include a general main processor and one or more special coprocessors, such as a central processing unit (CPU), a graphics processing unit (GPU), a neural network processor (NPU), a digital signal processor (DSP), etc. In the RAM 1003, various programs and data required for the operation of the device 1000 are also stored. The processor 1001, the ROM 1002 and the RAM 1003 are connected to each other through the bus 1004. The input / output (I / O) interface 1005 is also connected to the bus 1004.

[0137] The processor and the memory are used together to execute the program stored in the memory. When the program is executed by the computer, the methods, steps or functions described in the above embodiments can be implemented.

[0138] The following components are connected to the I / O interface 1005: an input section 1006 including a keyboard, a mouse, a touch screen, etc.; an output section 1007 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN card, a modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as needed, so that a computer program read therefrom is installed into the storage section 1008 as needed. Fig.12 The schematic diagram shows some components, which does not mean that the device 1000 only includes Fig.12 Component.

[0139] The systems, devices, modules or units described in the above embodiments may be implemented by a computer or its associated components. The computer may be, for example, a mobile terminal, a smart phone, a personal computer, a laptop computer, a vehicle-mounted human-computer interaction device, a personal digital assistant, a media player, a navigation device, a game console, a tablet computer, a wearable device, a smart TV, an Internet of Things system, a smart home, an industrial computer, a server or a combination thereof.

[0140] Although not shown, in an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the channel quantization table construction method described in the embodiment is implemented.

[0141] Storage media in embodiments of the present invention include permanent and non-permanent, removable and non-removable items that can be used to store information by any method or technology. Examples of storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

[0142] Although not shown, an embodiment of the present invention further provides a computer program product, including: a computer program / instruction, which implements the channel quantization table construction method described in the embodiment when executed by a processor.

[0143] The methods, programs, systems, devices, etc. of the embodiments of the present invention may be executed or implemented in a single or multiple networked computers, or may be practiced in a distributed computing environment. In the embodiments of this specification, in these distributed computing environments, tasks may be performed by remote processing devices connected via a communication network.

[0144] Those skilled in the art should understand that the embodiments of the present specification may be provided as methods, systems or computer program products. Therefore, those skilled in the art may imagine that the functional modules / units or controllers and related method steps described in the above embodiments may be implemented in software, hardware or a combination of software / hardware.

[0145] Unless explicitly stated, the actions or steps of the methods, programs, and embodiments of the present invention do not have to be performed in a specific order and can still achieve the desired results. In some implementations, multitasking and parallel processing are also possible or may be advantageous.

[0146] In this article, multiple embodiments of the present invention are described, but for the sake of simplicity, the description of each embodiment is not exhaustive, and the same or similar features or parts between the embodiments may be omitted. In this article, "one embodiment", "some embodiments", "example", "specific example", or "some examples" are intended to be applicable to at least one embodiment or example of the present invention, but not all embodiments. The above terms do not necessarily mean to refer to the same embodiment or example. In the absence of contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0147] The exemplary systems and methods of the present invention have been specifically shown and described with reference to the above embodiments, which are merely examples of the best modes for implementing the present systems and methods. It will be appreciated by those skilled in the art that various changes may be made to the embodiments of the systems and methods described herein when implementing the present systems and / or methods without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for constructing a channel quantization table, characterized in that: include: Divide the receiving plane into N sub-areas; quantizing the actual channel gain value of each point in the N sub-areas into the same channel gain value according to a preset rule; Constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-areas and the quantization gain value corresponding to each of the sub-areas; The step of constructing a channel quantization table for an indoor visible light communication system according to the divided N sub-regions and the quantization gain value corresponding to each of the sub-regions includes: Obtaining normalized boundary values ​​of each sub-region and quantized channel gain values; The boundary value interval after normalization of the height in the receiving plane is associated with the quantized channel gain value corresponding to each of the sub-areas to construct a quantized channel gain table.

2. The channel quantization table construction method according to claim 1, characterized in that: The step of dividing the receiving plane into N sub-areas includes: The receiving plane is divided into the N sub-areas at equal intervals, or the receiving plane is divided into the N sub-areas at approximately equal quantization errors.

3. The channel quantization table construction method according to claim 2, characterized in that: The step of dividing the receiving plane into N sub-areas at equal intervals includes: The receiving plane is divided into a plurality of concentric rings at equal intervals, and each concentric ring is one of the sub-areas.

4. The channel quantization table construction method according to claim 3, characterized in that: The step of quantizing the actual channel gain values ​​of each point in the N sub-areas into the same channel gain value according to a preset rule comprises: The quantized channel gain value of the sub-area is obtained according to the maximum radius of the receiving plane and the distance from the outer wall to the center of the sub-area.

5. The channel quantization table construction method according to claim 2, characterized in that: The step of dividing the receiving plane into N sub-areas with approximately equal quantization errors includes: Dividing the receiving plane into two first sub-areas with equal quantization errors; Dividing the two first sub-regions into two second sub-regions with equal quantization errors; Repeat the above division steps until the division is completed.

6. The method for constructing a channel quantization table according to any one of claims 1 to 5, characterized in that: The number of the N sub-regions is a power of 2.

7. The channel quantization table construction method according to claim 5, characterized in that: The method further comprises: According to the channel gain quantization errors of the two sub-regions with equal quantization errors, obtaining the channel gain value at the boundary of the two sub-regions; A dividing point between the two sub-areas is obtained according to the channel gain value at the dividing point.

8. An indoor visible light communication system, characterized in that: The indoor visible light communication system comprises: Terminals, base stations and central controllers; The terminal feeds back location information to the base station via an uplink; The base station aggregates the received location information to the central controller; The central controller obtains the channel information of the terminal by looking up the channel quantization table constructed according to the channel quantization table construction method according to any one of claims 1 to 7 according to the received location information.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the channel quantization table construction method described in any one of claims 1 to 7.

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