Vertical switching method of visible light communication heterogeneous networking based on special indoor scenes

Abstract

The present invention relates to the technical field of visible light communication, and in particular to a visible light communication heterogeneous networking vertical switching method based on a special indoor scene. In terms of network architecture, a solution combining VLC communication, Ir communication and traditional RF communication is adopted. Through the complementary advantages and disadvantages of the three communication modes, an optical link with a higher data rate is preferentially used, so that the overall communication capacity and rate are improved. Specifically, according to the blocking situation of each visible light communication link and the situation of entering and exiting a common channel interference zone when moving in an optical network coverage area, the time residence before switching is dynamically adjusted. While minimizing the reduction of the communication rate and the overall signal quality, the number of switching is reduced, the ping-pong effect is alleviated, and the switching cost is reduced to a certain extent. In addition, combined with the user's perception of the delay time, the user experience quality QoE is improved, and the deficiencies of the prior art are made up.

Description

Technical Field

[0001] The present invention relates to the technical field of visible light communication, and in particular to a method for vertical switching of visible light communication heterogeneous networking based on special indoor scenarios. Background Art

[0002] In order to meet the increasing demand for broadband services in mobile communication networks in indoor environments and the shortage of spectrum resources, visible light communication has been included in the consideration of indoor networking. Visible light communication (VLC) has the advantages of not occupying authorized spectrum resources, not being affected by electromagnetic interference, high confidentiality, and green sustainability. As a supplement to traditional radio frequency for heterogeneous networking, it can realize high-speed and high-capacity mobile communication networks. At the same time, it can also be integrated with other millimeter wave communication technologies when facing special indoor scenarios.

[0003] However, in actual networking, the visible light communication link is easily blocked, resulting in signal interruption and triggering network switching. In addition, switching will also be performed when facing different business needs. Therefore, a heterogeneous networking vertical switching technology is designed that can dynamically adapt to user movement, avoid blockage, and meet real-time business needs, while targeting the characteristics of optical links.

[0004] In special indoor places such as mines, large underground parking lots, military bases, etc., visible light communication, infrared light communication and traditional radio frequency communication can be integrated to ensure confidentiality, freedom from electromagnetic interference, high-speed and high-capacity communication, while also complementing the links to improve communication quality. On this basis, the vertical switching algorithm is improved and perfected to minimize the switching cost and ping-pong effect, and the different needs of real-time application users are taken into account, so that users can have higher communication quality and user experience quality when using different services. Summary of the invention

[0005] The purpose of the present invention is to provide a vertical switching method for visible light communication heterogeneous networking based on special indoor scenes, so that mobile users can obtain better experience in the heterogeneous fusion networking of visible light communication VLC, radio frequency communication RF and infrared light communication IR, and improve the communication quality.

[0006] To achieve the above object, the present invention provides a method for vertical switching of a heterogeneous visible light communication network based on a special indoor scene, comprising the following steps:

[0007] Step 1: Set up an indoor visible light communication heterogeneous networking environment consisting of multiple VLC access points, Ir access points and RF access points;

[0008] Step 2: Setting the priority switching of optical links in the indoor visible light communication heterogeneous networking environment;

[0009] Step 3: The user enters the networking environment and sends an access request to determine whether the visible light communication link is blocked. If it is not blocked and the link is available, the VLC link is connected and the process goes to step 5.

[0010] Step 4: If the VLC link is blocked and unavailable, set a dwell time, and wait for the dwell time to determine whether the VLC link is blocked again;

[0011] If the VLC link continues to be blocked, the Ir link or RF link is selected according to the communication range of the user;

[0012] If the VLC link is no longer blocked, return to step 3;

[0013] Step 5: The user moves in the networking environment to determine whether the VLC link is blocked and interrupted. If blocked, proceed to step 4.

[0014] If there is no obstruction, the indoor positioning technology and the perception of interference of similar optical signal strength are used to determine whether it has entered the co-channel interference area of ​​visible light communication;

[0015] Step 6: After entering the co-channel interference area, set a new dwell time again, wait for the new dwell time to expire, and determine again whether the user's location is still in the co-channel interference area. If so, determine whether it is in the Ir communication range;

[0016] If it is within the Ir communication range, it connects to the Ir link;

[0017] If otherwise go to step 7;

[0018] Step 7: Connect the RF link. If you have left the co-channel interference area, continue to use the VLC link and record the time and number of times you have passed through the co-channel interference area for the next dwell time calculation, and return to step 3.

[0019] Optionally, the indoor visible light communication heterogeneous networking environment includes VLC links, Ir links and RF links, and the optical links include VLC links and Ir links.

[0020] Optionally, the dwell time is determined by identifying the type of real-time application used by the user, and the dwell time before switching is performed according to the set time.

[0021] Optionally, in step 4, if the VLC link is no longer blocked, the process returns to step 3. Before returning to step 3, the time and number of blocking are recorded for calculation of a new residence time.

[0022] Optionally, the dwell time before switching is adjusted according to different service types to increase the user experience quality value when using various real-time applications.

[0023] The present invention provides a visible light communication heterogeneous networking vertical switching method based on special indoor scenarios. In terms of network architecture, a solution combining VLC communication, Ir communication and traditional RF communication is adopted. Through the complementary advantages and disadvantages of the three communication modes, optical links with higher data rates are preferentially used, so that the overall communication capacity and rate are improved. Specifically, according to the blocking situation of each visible light communication link and the situation of entering and exiting the common channel interference area when moving in the optical network coverage area, the time residence before switching is dynamically adjusted. While minimizing the reduction of the communication rate and the overall signal quality, the number of switching is reduced, the ping-pong effect is alleviated, and the switching cost is reduced to a certain extent. In addition, combined with the user's perception of the delay time, the user experience quality QoE is improved, which makes up for the shortcomings of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a flow chart of a method for vertical switching of heterogeneous visible light communication networks based on special indoor scenarios of the present invention.

[0026] Figure 2 It is a structural diagram of the indoor visible light communication heterogeneous networking framework of a specific embodiment of the present invention.

[0027] Figure 3 It is a schematic diagram of the switching solution flow of a specific embodiment of the present invention.

[0028] Figure 4 1 is a schematic diagram of a user random mobility model simulation in a specific embodiment of the present invention, wherein the user random mobility model is improved based on the random walk model and combined with the actual situation of random mobility of mobile terminal users in an indoor environment.

[0029] Figure 5 It is a curve diagram showing the link blocking model of the present invention changing with the recovery rate.

[0030] Figure 6 It is a schematic diagram comparing the performance of a specific embodiment of the present invention with several other time-dwelling vertical switching algorithms in heterogeneous visible light communication networks.

[0031] Figure 7It is a schematic diagram comparing the switching costs of time-resident vertical switching algorithms in a specific embodiment of the present invention and other visible light communication heterogeneous networks. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0033] See also Figure 1 The present invention provides a method for vertical switching of a visible light communication heterogeneous network based on a special indoor scene, comprising the following steps:

[0034] S1: Set up an indoor visible light communication heterogeneous networking environment consisting of multiple VLC access points, Ir access points and RF access points;

[0035] S2: Setting the optical link to be switched preferentially in the indoor visible light communication heterogeneous networking environment;

[0036] S3: The user enters the networking environment and sends an access request to determine whether the visible light communication link is blocked. If it is not blocked and the link is available, the VLC link is connected and the process proceeds to step S5;

[0037] S4: If the VLC link is blocked and unavailable, a dwell time is set, and after the dwell time has passed, it is determined again whether the VLC link is blocked;

[0038] If the VLC link continues to be blocked, the Ir link or RF link is selected according to the communication range of the user;

[0039] If the VLC link is no longer blocked, return to step S3;

[0040] S5: The user moves in the networking environment and determines whether the VLC link is blocked and interrupted. If blocked, proceed to step S4;

[0041] If there is no obstruction, the indoor positioning technology and the perception of interference of similar optical signal strength are used to determine whether it has entered the co-channel interference area of ​​visible light communication;

[0042] S6: After entering the co-channel interference area, a new dwell time is set again, and after waiting for the new dwell time to expire, it is determined again whether the user's location is still in the co-channel interference area. If so, it is determined whether it is in the Ir communication range;

[0043] If it is within the Ir communication range, it connects to the Ir link;

[0044] If otherwise, proceed to step S7;

[0045] S7: Connect the RF link. If the co-channel interference area has been left, continue to use the VLC link and record the time and number of times of passing through the co-channel interference area for the calculation of the next dwell time, and return to step S3.

[0046] Among them, the indoor visible light communication heterogeneous networking environment includes VLC links, Ir links and RF links, and the optical links include VLC links and Ir links.

[0047] The dwell time is determined by identifying the type of real-time application used by the user, and the dwell time before switching is performed according to the set time.

[0048] In step S4, if the VLC link is no longer blocked, the process returns to step S3. Before returning to step S3, the time and number of blocking are recorded for calculation of a new residence time.

[0049] Adjust the dwell time before switching according to different business types to increase the user experience quality value when using various real-time applications.

[0050] For further information, see 2 to Figure 4 The present invention also proposes a specific embodiment, which is further explained through simulation experiments and comparison with several other time-resident vertical switching algorithms in visible light communication heterogeneous networks:

[0051] 1. Environmental architecture: Assume a 6m*6m*3m indoor environment, consisting of 9 VLC access points, 4 Ir access points, and 1 RF access point, which is controlled by external power lines and a central control unit.

[0052] 2. User random movement model: The user movement model is improved on the basis of the random walk model to make it consistent with the real-life user's indoor movement. The specific movement can be described as: moving continuously in a random direction for a random period of time, then randomly stopping for a period of time, and then continuing the above movement. In the simulation, the movement direction is set to be random [0,2]; the maximum movement speed when walking fast is V max =1.4m / s, the maximum speed when walking slowly is V max =0.6m / s; the duration of each continuous movement is set to a random 2-10s, and the duration of each stay is set to a random 0-10s.

[0053] 3. The specific steps in the switching process are as follows Figure 3 As shown:

[0054] [1] The user enters the room and first requests to connect to the VLC link. Then, the user continues to move and stay randomly in the room. The probability of blocking conforms to the Poisson distribution. If the VLC link is blocked, the user proceeds to step [2]. If the VLC link is not blocked, the user proceeds to step [7].

[0055] [2] Determine the residence time before switching based on the type of real-time application currently running on the mobile terminal, and perform the residence time before switching according to the set time to reduce a certain switching cost.

[0056] 【3】If it is a real-time messaging application, the dwell time before switching is set to D1. D1 is determined based on the duration of the recorded long interruption and the maximum tolerance time of the user for the delay of real-time information data applications. The blocking time TBlock meets a set range. The recovery rate is inversely proportional to the terminal time, set to Gama = 1 / TBlock. Network users will lose interest in the current task when waiting for only 2 seconds; after 2 seconds, video viewers will start to leave the website; when it reaches 10 seconds, more than half of them will leave.

[0057] In summary, in real-time applications such as message interaction, the user's maximum tolerable delay time tdata can be set to 1.9 to 2.6 seconds; in real-time audio applications, taudio is set to 1.1 to 1.9 seconds; and in real-time video applications, tvideo is set to 0.2 to 1 second.

[0058] Compare TBlock with tdata. If the former is larger, the switch is immediate and D1 is 0. If the latter is larger, D1 is equal to the shortest time of the long interruption.

[0059] [4] If it is a real-time audio application, the dwell time before switching is set to D2. D2 is determined based on the average value of the recorded short interruptions. TBlock is compared with taudio. If the former is larger, the application switches immediately and D2 is 0. If the latter is larger, D2 is equal to the longest duration of the short interruption.

[0060] [5] If it is a real-time video application, it is extremely sensitive to link interruption. The actual user experience is the main factor. The dwell time D3 is determined according to the user's maximum tolerance for delay. TBlock is compared with tvideo. If the former is larger, it is switched immediately and D3 is 0. If the latter is larger, D3 is equal to the average of the maximum tolerance time tvideo for video application delay and the maximum short interruption time. The minimum short interruption time is set to twmax = 2s, that is, sum([tvideo, twmax]) / 2.

[0061] [6] After the dwell time is reached, the current status of the mobile terminal and the link is determined. If the VLC link is still blocked, it is determined whether the mobile terminal is within the Ir communication coverage. If not, it is switched to RF communication. If so, it is connected to Ir communication. If the VLC link is not blocked, it returns to step [1].

[0062] like Figure 5 As shown, Figure 5 It is a curve diagram showing the link blocking model changing with the recovery rate.

[0063] [7] If the VLC is not blocked, determine whether the mobile terminal is in the CCI (common channel interference) area. If the mobile terminal is not in the CCI area, return to step [1]. If it is in the CCI area, determine the residence time before switching based on the type of real-time application currently running on the mobile terminal. Perform the residence time before switching based on the set time to reduce a certain switching cost.

[0064] 【8】If the mobile terminal is using real-time applications such as information interaction or web browsing, the dwell time before switching is set to D4. D4 is determined based on the time to pass through the CCI area and the maximum tolerance time of the user for information data application delay. According to the position of VLCAPs in the network architecture, the coverage radius is approximately (m). The longest and shortest distances between its coverage area and the overlapping area are calculated to obtain the average distance L of the coverage area. The expected time to pass through the overlapping area is the ratio between the average distance L and the real-time speed of the user's movement, which is set as TCCI. Then TCCI is compared with tdata. If the former is larger, D4 is 0 and switching is performed immediately; if the latter is larger, the maximum tolerance time for information interaction application interruption tdata and TCCI is the maximum value of max(max(Ttext),ETfile(n_Ac_VHO)).

[0065] [9] If a real-time application such as audio playback and interaction is in progress, the dwell time before switching is set to D5. D5 is determined based on the recorded average time of passing through the CCI area and the user's maximum tolerance time for delays in real-time applications such as audio interaction and playback. TCCI is compared with taudio. If the former is larger, D5 is 0 and switching is performed immediately. If the latter is larger, D5 is set to sum([taudio,TCCI]) / 2.

[0066]

[10] If a real-time application such as video playback and interaction is running, the dwell time before switching is set to D6. D6 is determined based on the user's maximum tolerance for the delay time of real-time video applications. TCCI is compared with tvideo. If the former is larger, D6 is 0 and switching is performed immediately. If the latter is larger, D6 is set to the minimum value min(Tvideo) of the tolerance time for the interruption of real-time video applications.

[0067]

[11] After the dwell time is reached, the current status of the mobile terminal and the link is determined. If the mobile terminal is still in the CCI area, it is determined whether the mobile terminal is in the Ir communication coverage range. If not, it is switched to RF communication. If so, it is connected to Ir communication. If the mobile terminal is not in the CCI area, then it returns to step [1].

[0068] Further, in a specific embodiment, the method of the present invention is compared with several other time-dwelling vertical switching algorithms in heterogeneous visible light communication networks in terms of performance and cost. Figure 6 and Figure 7 , Figure 6 This is a performance comparison of the method of the present invention compared with several other time-resident vertical switching algorithms in visible light communication heterogeneous networks. It can be seen that there is a significant improvement in overall QoE and data transmission rate.

[0069] like Figure 7 As shown, compared with the switching cost comparison of several other time-resident vertical switching algorithms in visible light communication heterogeneous networks, it can be seen that the switching cost of the present invention, namely (Ac-VHO), is significantly reduced.

[0070] In summary, the present invention has the following advantages:

[0071] 1. According to the blocking situation of each visible light communication link and the situation of entering and exiting the common channel interference area when moving in the optical network coverage area, the time residence before switching is dynamically adjusted to reduce the number of switching while minimizing the communication rate and overall signal quality, alleviate the ping-pong effect, and reduce the switching cost to a certain extent.

[0072] 2. Adjust the time residence before switching according to different business types, increase the overall user experience quality (QoE) value when using various real-time applications, and also reduce a certain ping-pong effect, that is, the switching cost, which is significantly reduced.

[0073] 3. Optical links (VLC and Ir) are given priority during switching, which results in a higher overall communication rate and improves the overall QoE value.

[0074] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for vertical switching of heterogeneous visible light communication networks based on special indoor scenarios, characterized in that: The following steps are involved: Step 1: Set up an indoor visible light communication heterogeneous networking environment consisting of multiple VLC access points, Ir access points and RF access points; Step 2: Setting the priority switching of optical links in the indoor visible light communication heterogeneous networking environment; Step 3: The user enters the networking environment and sends an access request to determine whether the visible light communication link is blocked. If it is not blocked and the link is available, the VLC link is connected and the process goes to step 5. Step 4: If the VLC link is blocked and unavailable, set a dwell time, and wait for the dwell time to determine whether the VLC link is blocked again; If the VLC link continues to be blocked, the Ir link or RF link is selected according to the communication range of the user; If the VLC link is no longer blocked, return to step 3; Step 5: The user moves in the networking environment to determine whether the VLC link is blocked and interrupted. If blocked, proceed to step 4. If there is no obstruction, the indoor positioning technology and the perception of interference of similar optical signal strength are used to determine whether it has entered the co-channel interference area of ​​visible light communication; Step 6: After entering the co-channel interference area, set a new dwell time again, wait for the new dwell time to expire, and determine again whether the user's location is still in the co-channel interference area. If so, determine whether it is in the Ir communication range; If it is within the Ir communication range, it connects to the Ir link; If otherwise go to step 7; Step 7: Connect the RF link. If you have left the co-channel interference area, continue to use the VLC link and record the time and number of times you have passed through the co-channel interference area for the next dwell time calculation, and return to step 3.

2. The method for vertical switching of visible light communication heterogeneous networks based on special indoor scenarios according to claim 1, characterized in that: The indoor visible light communication heterogeneous networking environment includes a VLC link, an Ir link and an RF link, and the optical link includes a VLC link and an Ir link.

3. The method for vertical switching of heterogeneous visible light communication networks based on special indoor scenarios according to claim 2, characterized in that: The dwell time is determined by identifying the type of real-time application used by the user, and the dwell time before switching is performed according to the set time.

4. The method for vertical switching of heterogeneous visible light communication networks based on special indoor scenarios according to claim 3, characterized in that: In step 4, if the VLC link is no longer blocked, the process returns to step 3. Before returning to step 3, the blocking time and number of times are recorded for calculation of a new residence time.

5. The method for vertical switching of heterogeneous visible light communication networks based on special indoor scenarios according to claim 4, characterized in that: Adjust the dwell time before switching according to different business types to increase the user experience quality value when using various real-time applications.

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