Cooperative optimization of user access and power allocation for visible light-radio frequency networks

Abstract

The application discloses a method for cooperatively optimizing user access and power allocation of a visible light-radio frequency network, and belongs to the technical field of optical wireless access communication and resource optimization. The method is directed to an indoor multi-access point and multi-user scenario of the visible light-radio frequency network, and classifies indoor users by acquiring network parameters, user distribution, channel state and service demand information. Secondly, a two-stage access mechanism is adopted to complete matching of the users and the visible light access points, and relay selection is performed for edge users and blind area users. Then, power optimization allocation is performed on the basis of meeting minimum rate requirements. Finally, a joint iterative optimization method is adopted to optimize access, relay selection and power allocation, so as to improve the network total throughput, user fairness and system communication reliability of the visible light-radio frequency network.

Description

Technical Field

[0001] This invention relates to the field of wireless communication and resource optimization technology, specifically to a user-relay-enabled hybrid visible light communication (VLC) and radio frequency (RF) network access and resource allocation method, belonging to the field of collaborative transmission and optimization control technology for hybrid heterogeneous communication networks. This method addresses indoor communication scenarios with line-of-sight link congestion, uneven coverage, and differences in user service quality. By jointly optimizing user access, relay selection, and power allocation, it improves system throughput and user fairness. Background Technology

[0002] With the rapid development of the Internet of Things (IoT), smart sensing, and indoor wireless access technologies, the demand for communication with high bandwidth, low latency, and high reliability is constantly increasing. While traditional radio frequency (RF) communication is widely used, it suffers from problems such as limited spectrum resources and significant electromagnetic interference, which can easily limit its transmission performance and system capacity in high-density indoor environments. Visible light communication (VLC), utilizing the visible light band for integrated lighting and communication transmission, offers advantages such as abundant spectrum resources, no licensing required, strong resistance to electromagnetic interference, and suitability for high-precision indoor sensing and positioning. Therefore, visible light communication technology has promising application prospects in indoor IoT and smart sensing networks.

[0003] However, standalone VLC communication still has significant limitations. For example, visible light communication typically relies on line-of-sight links to transmit data, and these links are easily affected by human obstruction, obstacles, and changes in the receiving field of view, leading to degraded or interrupted signal quality. Furthermore, the radiation power of a single VLC access point (AP) is relatively low, limiting its coverage area. In scenarios with uneven user distribution or numerous edge areas, problems such as VLC coverage blind spots, decreased communication quality for edge users, and significant differences in user service quality can easily arise.

[0004] To address the aforementioned issues, hybrid VLC-RF networks leverage the complementary advantages of visible light and radio frequency (RF) communication. VLC provides high-speed data transmission while RF enhances system coverage and transmission link reliability. Furthermore, introducing a relay cooperation mechanism into the hybrid VLC-RF network can more effectively extend the VLC communication range, mitigate performance degradation caused by line-of-sight blocking, and further improve access communication rates for users in blind spots and at the edge, thus enhancing their access experience.

[0005] In existing technologies, research on hybrid VLC-RF networks mainly focuses on user access, relay selection, and power allocation, and some progress has been made. However, existing methods still have the following shortcomings:

[0006] 1) The process of users accessing the VLC-RF network lacks comprehensive consideration of load balancing at each access point and user needs. Existing access methods often make access decisions based on the strongest channel gain or the shortest distance. Although this is relatively simple to implement, it can easily overload some visible light access points, leading to uneven system load distribution and exacerbating co-channel interference in multi-access point scenarios, thus affecting the throughput of the VLC-RF network.

[0007] 2) The relay selection mechanism in VLC-RF networks does not adequately consider user type differences and end-to-end link quality. In hybrid VLC-RF networks with blind spots and edge users, different types of users have varying degrees of reliance on relay assistance. Some existing relay selection methods often match relays based solely on single-hop channel quality, nearest distance, or local link metrics, failing to comprehensively consider user service requirements, candidate relay availability, and the overall transmission performance of the relay link. Consequently, it is difficult to balance system throughput and user fairness.

[0008] 3) Power allocation methods in VLC-RF networks struggle to balance system efficiency and user fairness. Traditional power allocation methods, such as padding, tend to allocate more resources to users with better channel conditions. While this helps improve the overall system rate, it can easily put edge users or users in blind spots with poor channel conditions at a long-term disadvantage, widening the gap in service quality among users and thus reducing network fairness.

[0009] 4) Lack of unified and coordinated optimization for user access, relay selection, and power allocation in VLC-RF networks. User access, relay selection, and power allocation in hybrid VLC-RF networks are coupled with each other. Optimizing any one of these aspects alone often fails to achieve the overall optimal effect, especially in scenarios with multiple access points, multiple users, and multiple relays. The related optimization problems usually manifest as mixed integer non-convex problems with high solution complexity. Existing technologies lack an efficient joint optimization method that can balance system throughput, user fairness, and implementation complexity.

[0010] Therefore, there is an urgent need to propose a collaborative optimization method for user access and power allocation in visible light-radio frequency networks, so as to achieve collaborative optimization of user access, relay selection and power allocation in multi-access point, multi-user indoor communication scenarios, thereby improving the total network throughput, improving user fairness, and enhancing the system's adaptability to line-of-sight blocking and coverage blind spot scenarios. Summary of the Invention

[0011] The technical problem this invention aims to solve is: addressing the issues in existing hybrid visible light communication (VLC) and radio frequency (RF) networks, such as easy congestion of line-of-sight links, limited coverage, degraded service quality for edge and blind spot users, uneven load distribution at access points, unreasonable relay selection, and difficulty in balancing system throughput and user fairness in power allocation. This invention proposes a collaborative optimization method for user access and power allocation in visible light-RF networks to achieve collaborative optimization of user access, relay selection, and power allocation in multi-access-point, multi-user scenarios, thereby improving overall network throughput, user fairness, and system communication reliability. To solve the above technical problems, this invention adopts the following technical solution: a collaborative optimization method for user access and power allocation in visible light-RF networks, characterized by the following steps:

[0012] S1: The VLC-RF network obtains information such as resource status and performance parameters of each access point in the hybrid visible light-radio frequency network, user distribution and location information, channel status information, service requirements, and constraints that indoor equipment transmission and reception power need to meet through location detection and communication protocol analysis, and establishes the network topology relationship between users and the visible light-radio frequency network.

[0013] Among them, the edge user mentioned in S2 is a user located at the edge of the visible light access point coverage and with poor channel quality; the blind zone user is a user in the visible light coverage blind zone or where the line-of-sight link is completely blocked; and the relay candidate user is a user who has auxiliary forwarding capability after completing its own access.

[0014] S3: A two-stage access mechanism is adopted to complete the access matching between users and visible light access points, and to determine the access relationship between relay users and edge users;

[0015] Furthermore, the two-stage access mechanism in S3 includes: in the first stage, users with better link conditions and suitable for undertaking collaborative tasks are given priority to access the corresponding visible light access point and orthogonal resources are allocated to them to determine the relay user set; in the second stage, the remaining edge users are enabled to reuse existing resources to complete the access without destroying the access results of the first stage.

[0016] Furthermore, in S3, the decision on access matching for edge users comprehensively considers the user's service rate requirements and link channel quality. The priority of user access matching is defined based on the ratio of the user's service rate requirements to the link channel quality, so as to improve resource utilization and alleviate the problem of uneven load on access points.

[0017] S4: For edge users and users in blind spots who need auxiliary transmission, based on link quality, user service needs and relay availability, perform relay selection and establish a visible light relay auxiliary communication link or a radio frequency relay auxiliary communication link.

[0018] In the relay selection in S4, each edge user or blind spot user may select at most one relay user to establish an auxiliary transmission relationship, and each relay user may provide forwarding services to at most one auxiliary user; for any user that needs auxiliary transmission, only one of the visible light relay link or radio frequency relay link is allowed to be selected as the auxiliary transmission mode within the same scheduling period;

[0019] Among them, the relay-assisted communication link in S4 uses a relay forwarding method to complete two-hop transmission for users in the blind zone; for edge users, while retaining the direct link between them and the visible light access point, a relay-assisted link is introduced to form cooperative transmission.

[0020] S5: Based on meeting the minimum rate requirements of users, optimize the power allocation of the system by combining user priority and historical contribution factors;

[0021] Specifically, the power allocation of the optimization system in S5 includes: first, allocating basic power to connected users to meet the minimum service rate requirements; then, within the remaining allocable power range, performing secondary optimization allocation of power resources based on the user's current service needs, link status, cooperation relationships, and historical service conditions.

[0022] S6: Perform joint iterative optimization on the user access, relay selection and power allocation results until the convergence condition is met, and then output the final resource allocation result;

[0023] The joint iterative optimization process in S6 is as follows: update the relay selection relationship according to the current user access status, adjust the power allocation according to the updated relay relationship and resource occupancy, and re-evaluate the access rationality and relay cooperation effect according to the updated resource allocation result. This process is repeated until the system performance becomes stable or the preset stopping condition is met.

[0024] Furthermore, in the user classification method described in step S2, indoor users are divided into ordinary users, edge users, blind spot users, and relay users based on the line-of-sight link status and coverage of the user and the nearest access point. Blind spot users are those located in visible light coverage blind spots or where the line-of-sight link is completely blocked, while edge users are those located at the edge of the visible light access point's coverage and with poor channel quality. Blind spot users rely on relay auxiliary equipment to complete VLC line-of-sight link access to the VLC-RF network, while edge users can transmit via direct links to the visible light access point or form cooperative transmission links with the help of relay users, thereby improving transmission reliability in edge areas.

[0025] To ensure the feasibility of relay-assisted transmission, this invention imposes uniform constraints on the auxiliary transmission frequency band in step S2. For any user u requiring auxiliary transmission, the choice between a visible light relay link and a radio frequency relay link satisfies the following:

[0026] ;

[0027] In the above formula, Both are binary variables. This indicates that user u is using visible light relay link transmission mode. This indicates that user u uses an RF relay link to transmit data; the above constraints ensure that each auxiliary user can select at most one relay forwarding mode, thereby reducing the complexity of system control and avoiding users repeatedly occupying VLC or RF resources.

[0028] In step S3, this invention employs an access matching decision mechanism that considers both the service requirements requested by the user and the channel state. For edge users, the priority factor for access matching can be expressed as:

[0029] ;

[0030] In the above formula, Priority factor for access matching of subchannel k of VLC AP m for edge user m. This represents the service rate requirement value for the nth user. This represents the channel gain between user n and the k-th sub-channel of the m-th visible light access point. The larger the value, the higher the user's access matching priority. The priority factor can simultaneously reflect the user's rate demand and link quality, so that users with high rate demand and users with weak channels can obtain more reasonable access opportunities in resource competition, thereby alleviating the problem of uneven load and reduced user fairness caused by the traditional strongest channel access method. The formula for calculating the channel gain between user n and subchannel k of VLC AP m, based on the Lambert radiation model, is as follows:

[0031] ;

[0032] In the above formula, l is the Lambert radiation coefficient, and its value is: ,in It is the half-power angle of the VLC AP; This indicates the receiving area of ​​the optical receiver; User With VLC AP The straight-line distance; The LED emission angle at the VLC AP end; The angle of incidence at the receiving end; This refers to the receiver's field of view (FoV). and These represent the gain of the receiver's filter and condenser, respectively.

[0033] In step S4, to constrain the relay cooperation relationships of users, this invention constructs a relay selection matrix, whose elements... Let be a binary variable, where, The relay user r provides an auxiliary transmission link for user u. This indicates that user r does not provide cooperative transport for user u. Therefore, defining a relay cooperative relationship requires satisfying the following conditions:

[0034] ;

[0035] The above constraint formula shows that each edge user or blind spot user can select at most one relay user, and each relay user can provide an auxiliary communication link for at most one edge user or blind spot user, thereby avoiding excessive competition for relay resources and ensuring the stability of the relay link.

[0036] For user b in the blind zone, this invention uses a decoding-forwarding method to complete relay-assisted transmission, with an end-to-end achievable rate. It can be represented as:

[0037] ;

[0038] In the above formula, This represents the transmission rate from the visible light access point m to the relay user r. This represents the forwarding rate from relay user r to user b in the dead zone; The formula shows that the effective communication capability of users in the dead zone is determined by the transmission rate of the weaker hop in the two-hop link. Therefore, this invention can comprehensively consider the quality of the access link and the quality of the forwarding link when selecting relays, so as to improve the transmission reliability in blind areas.

[0039] In step S4, for edge users, the present invention simultaneously retains both the visible light direct link and the relay auxiliary link, and adopts a cooperative transmission method to improve the performance of the edge area; the equivalent received signal-to-interference-plus-noise ratio of edge user e. It can be represented as:

[0040] ;

[0041] In the above formula, The received signal-to-interference-plus-noise ratio (SIR) is the line-of-sight link transmission value between visible light access point m and edge user e. The received signal-to-interference-plus-noise ratio (SIR) of the RF relay auxiliary link between relay user r and edge user e;

[0042] Correspondingly, the cooperative transmission rate of edge user e It can be represented as:

[0043] ;

[0044] In the above formula, B represents the bandwidth allocated to the user from the VLC access point.

[0045] This cooperative transmission mechanism can significantly improve the transmission rate for users in blind spots and at the edge, thereby improving the communication performance of edge users in areas with weak coverage.

[0046] In step S5, regarding power allocation, this invention does not simply employ the traditional water-filling method. Instead, based on meeting the user's minimum rate requirements, it introduces user priority weights and historical contribution factors to perform weighted optimization allocation of the remaining power. For any visible light access point m, its remaining allocable power... It can be represented as:

[0047] ;

[0048] in, U represents the maximum available transmit power of the m-th visible light access point; m This represents the set of users connected to access point m. This represents the minimum power required to meet the minimum rate requirement of the i-th user.

[0049] Furthermore, in S5, to prevent users with poor channel conditions from being at a long-term disadvantage in resource allocation, this invention uses a weighting coefficient that combines historical contributions to determine the order in which users are preferentially allocated power; the priority factor w for power allocation to user i... i for:

[0050] ;

[0051] in, This represents the rate gain of user i, specifically calculated as the difference between the transmission rate after the user increases the allocated unit power and the transmission rate without increasing the allocated unit power. This represents the historical contribution factor of user i. The weighting coefficient represents the historical contribution.

[0052] Based on the remaining power of the visible light access point m, it is preferentially allocated to w. i The user with the largest value; therefore, the power allocation value P after user i receives the remaining power. i for:

[0053] ;

[0054] In the above formula, This represents the increased power value allocated to user i based on priority weight. .

[0055] By employing the aforementioned power allocation method, this invention can improve the overall network throughput while ensuring fairness in resource allocation for users.

[0056] This invention ultimately aims to maximize the total system throughput as the joint optimization objective. It collaboratively solves for the user access matrix x, relay selection matrix u, and power allocation matrix p. The objective function for the VLC-RF network can be expressed as:

[0057] ;

[0058] Where x represents the user access matrix, u represents the relay selection matrix, p represents the power allocation matrix, RU represents the relay user set, EU represents the edge user set, BU represents the blind zone user set, and R r This refers to the transmission rate value obtained when a relay user r directly accesses a VLC or RF access point. Through the above joint optimization, this invention can simultaneously improve the overall network rate, expand coverage, and enhance user fairness in complex scenarios involving multiple access points, multiple users, and relay cooperation.

[0059] Compared with existing technologies, this invention effectively alleviates problems such as coverage blind spots, edge performance degradation, load imbalance, and unfair resource allocation in hybrid visible light-RF networks by integrating user access, relay selection, and power allocation into a unified framework for collaborative optimization. It has good system throughput improvement effect and engineering application value. Attached Figure Description

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the figures, wherein:

[0061] Figure 1 A schematic diagram of a relay cooperative transmission model in a hybrid VLC-RF network;

[0062] Figure 2 A schematic diagram of a VLC-RF network system model for indoor user relay collaboration;

[0063] Figure 3 Flowchart of a two-phase matching-based user access algorithm for hybrid VLC-RF networks;

[0064] Figure 4 A flowchart of a user priority-based relay selection algorithm for a hybrid VLC-RF network;

[0065] Figure 5 Flowchart of a priority-based weighted water-filling heuristic power allocation algorithm for hybrid VLC-RF networks;

[0066] Figure 6 A flowchart of the joint user access, relay selection, and power allocation optimization algorithm for hybrid VLC-RF networks. Detailed Implementation

[0067] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0068] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures, and should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0069] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0070] Figure 1 This diagram illustrates a relay cooperative transmission model in a hybrid VLC-RF network, including three scenarios. Scenario (a) shows a user within the coverage area of ​​a VLC access point, establishing an unobstructed VLC line-of-sight link for data transmission. Scenario (b) illustrates communication assistance for users in blind spots via a VLC link. These users access the VLC access point through relay users and receive VLC communication resource allocation. The connection control signal between the blind user and the relay user is transmitted via RF. Scenario (c) illustrates communication assistance for edge users via a VLC link. The VLC signal power received by edge users is relatively weak. To improve the communication rate, relay users can assist in enhancing the edge user's receiving power. Therefore, the edge user's received power is the sum of the relay user's forwarding power and the power received from the VLC access point. Similarly, the connection control signal between the edge user and the relay user is transmitted via RF.

[0071] Figure 2This is a schematic diagram of a VLC-RF network system model for indoor user relay collaboration. The model includes multiple VLC APs (access points), one RF AP, and multiple users. Each VLC AP is installed on the ceiling and equipped with a set of LEDs for indoor lighting and communication; the RF AP is installed in the center area of ​​one wall of the room. Figure 2 Figure (a) is a front view of the VLC-RF system model; Figure (b) is a top view of the VLC-RF system model. Figure 2 Figures (a) and (b) show that the user distribution map indicates that some users are within the VLC access point coverage area, some are located at the edge of the VLC access point, and some are located in the VLC access point blind spot. Users within the room are categorized into normal users and blind spot users. Normal users are defined as those within the VLC AP coverage area whose line-of-sight links are not blocked; blind spot users are defined as those outside the VLC AP coverage area who cannot establish a line-of-sight communication link with the VLC AP. Normal users can be further divided into relay users and edge users. Relay users are normal users within the VLC access point coverage area whose received power meets communication requirements, and some of their communication resources can be used to assist other users in establishing auxiliary communication links; edge users are those located at the edge of the VLC access point whose received power does not meet communication rate requirements. Figure 2 All VLC APs in the room adopt a unified orthogonal sub-channel configuration, and the bandwidth of each sub-channel is allocated equally. All users in the room are equipped with a hybrid receiver with an integrated photoelectric detector (PD) and RF antenna, which is used to receive VLC signals and RF signals respectively. The PD is oriented vertically upwards. All VLC APs and RF APs are centrally controlled by the central control unit of the control center through a communication protocol.

[0072] Figure 3 Flowchart of a two-phase matching-based user access algorithm for hybrid VLC-RF networks;

[0073] Input: VLC AP set M; user set N; user request rate; user location and channel state information;

[0074] Output: User access matrix x; relay user set RU; edge user set EU; blind zone user set BU.

[0075] The specific steps include:

[0076] Step 301: The control center of the VLC-RF network obtains user location, channel status, and user service requirements;

[0077] Step 302: Using the Lambert radiance model, calculate the channel gain between the user and each VLC AP. Sort the VLC APs in descending order of the number of sub-channels and the channel gain value of the user accessing the VLC AP, and construct a preference order table for user access allowed by each VLC AP.

[0078] Step 303: Arrange users and each VLC AP in descending order of channel gain, and construct a user access VLCAP preference order table for each user; save users whose line-of-sight channel gain cannot be calculated in the blind zone user set BU;

[0079] Step 304: Perform the first-stage matching, prioritizing the user with the best channel conditions to access the VLC AP for each VLC AP, and update the user access matrix x;

[0080] Step 305: Determine the relay user set RU based on the number of VLC AP sub-channels and the criterion that each relay user only assists one edge or blind zone user;

[0081] Step 306: If there are still users in the VLC-RF network who have not connected to the VLC AP, then according to the user's preference order table for connecting to the VLC AP, search in turn to see if there is a VLC AP that can accept the user's access.

[0082] Step 307: Save users who have not yet connected to the VLC AP in the edge user set EU, and update the user access matrix x;

[0083] Step 308: Output the user access matrix x; RU, EU and BU.

[0084] Figure 4 A flowchart of a user priority-based relay selection algorithm for a hybrid VLC-RF network;

[0085] Inputs: VLC AP set M, sub-channel set K, edge user set EU; blind zone user set BU; relay user set RU; user request rate;

[0086] Output: Relay selection matrix μ.

[0087] The specific steps include:

[0088] Step 401: Calculate the priority factor for edge user access matching in the EU set. ;

[0089] Step 402: Sort edge users in the set EU in descending order according to priority factor;

[0090] Step 403: Calculate the RF channel gain of each edge user and users in the RU set, sort them in descending order of channel gain, and construct a preference list of each edge user for relay users;

[0091] Step 404: Calculate the channel gain for each relay user and the edge users in the EU, sort them in descending order of channel gain, and construct a preference list for each relay user to edge users;

[0092] Step 405: For each user in the EU, select the preferred relay user for the highest priority user first, based on priority.

[0093] Step 406: Determine whether the relay user is in its communication idle time. If so, establish a communication link between the relay user and the edge user matching in the list, and update the relay selection matrix μ; otherwise, delete the relay user from the relay user's preference list and go to step S405.

[0094] Step 407: Repeat steps S405 and S406 until access matching for all users in all EUs is completed, then proceed to step S408;

[0095] Step 408: Output the relay selection matrix μ result.

[0096] Figure 5 Flowchart of a priority-based weighted water-filling heuristic power allocation algorithm for hybrid VLC-RF networks;

[0097] Input: VLC AP set M; user set N; user access matrix x; relay user set RU; edge user set EU, blind zone user set BU and relay selection matrix μ; demand rate and minimum demand rate values ​​for each user, historical contribution factor of each user; maximum transmit power value of each VLC AP;

[0098] Output: Power allocation vector p for each user.

[0099] The specific steps include:

[0100] Step 501: Based on the user's access matrix x and the user's minimum required rate value, and according to the user category (RU, EU, or BU), calculate the minimum transmit power value required for each user to meet the minimum required transmission rate value using their respective transmission rate formulas. ;

[0101] Step 502: Assign minimum power values ​​to users in the VLC APs they access. ;

[0102] Step 503: Calculate the remaining power value of each VLC AP. ,in, U represents the maximum available transmit power of the m-th VLC AP; m This represents the set of users connected to VLC AP m;

[0103] Step 504: For each VLC AP m, calculate the priority factor for user power allocation to VLC AP m. ,in, This represents the rate gain of user i, specifically calculated as the difference between the transmission rate after the user increases the allocated unit power and the transmission rate without increasing the allocated unit power. This represents the historical contribution factor of user i. The weighting coefficient represents the historical contribution.

[0104] Step 505: For each VLC AP, increase the power allocation according to the user's priority factor using a weighted water injection principle. The increased power allocation value is: ;

[0105] Step 506: Update the power values ​​allocated to each user. The power allocation update formula for each user is as follows: Stored in the user's power allocation vector middle;

[0106] Step 507: Output the user's power allocation vector p.

[0107] Figure 6 A flowchart of the joint user access, relay selection, and power allocation optimization algorithm for hybrid VLC-RF networks.

[0108] Input: VLC AP set M; user set N; maximum transmit power and subchannel state information of each VLC AP, user location and channel state information; minimum user demand rate and user request rate; set R*=0, maximum number of iterations I; network throughput increment threshold. ;

[0109] Output: User access matrix x; relay selection matrix μ; power allocation vector p; VLC-RF network throughput.

[0110] The specific steps include:

[0111] Step 601: Let Let the iterative calculator be t=1;

[0112] Step 602: The control center of the VLC-RF network obtains user location, channel status, and user service requirements;

[0113] Execute a two-phase user access algorithm;

[0114] Step 603: Execute Figure 3 The user access algorithm based on two-stage matching in the VLC-RF network shown obtains the user access matrix x, the relay user set RU, the edge user set EU, and the blind zone user set BU.

[0115] Step 604: Execute Figure 4 The relay selection algorithm based on user priority in the VLC-RF network shown obtains the relay selection matrix μ;

[0116] Step 605: Execute Figure 5 The priority-based weighted water-filling heuristic power allocation algorithm for the hybrid VLC-RF network shown obtains the power allocation vector p for each user;

[0117] Step 606: Calculate the network throughput of VLC-RF ;

[0118] Step 607: If R sum >R*, go to step 608; otherwise, let t = t+1 and go to step S601;

[0119] Step 608: If Proceed to step 610; otherwise, let R*=R sum Proceed to step 609;

[0120] Step 609: If t = 1, go to step 610; otherwise, let t = t + 1 and go to step 601.

[0121] Step 610: Output the network throughput R of VLC-RF sum , x, μ and p.

[0122] The above steps fully describe the virtual network mapping and allocation process of the elastic optical network based on hierarchical reinforcement learning, and supplement possible optimization measures to ensure better performance in practical applications of the algorithm.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for collaboratively optimizing user access and power allocation in a visible light-radio frequency network, characterized in that, For indoor hybrid visible light-RF communication systems comprising multiple visible light access points, one radio frequency access point, and multiple indoor users, the following steps are included: S1: Based on information such as the resource status and performance parameters of visible light access points and radio frequency access points in the visible light-radio frequency network, user distribution and location, channel status, service requirements and power constraints, establish the network topology relationship between users and the visible light-radio frequency network. S2: In the network topology, users are classified according to their location, the line-of-sight link status between the user and the nearest access point, and the communication quality, to determine the set of ordinary users, edge users, blind spot users, and relay candidate users. Among them, the edge user mentioned in S2 is a user located at the edge of the visible light access point coverage and with poor channel quality; the blind zone user is a user in the visible light coverage blind zone or where the line-of-sight link is completely blocked; and the relay candidate user is a user who has auxiliary forwarding capability after completing its own access. S3: A two-stage access mechanism is adopted to complete the access matching between users and visible light access points, and to determine the access relationship between relay users and edge users; The two-stage access mechanism in S3 includes: in the first stage, users with better link conditions and suitable for undertaking collaborative tasks are given priority to access the corresponding visible light access point and orthogonal resources are allocated to them to determine the relay user set; in the second stage, the remaining edge users can reuse existing resources to complete the access without destroying the access results of the first stage. In S3, the decision on the access relationship of edge users takes into account both the user's service rate requirements and the link channel quality, so as to improve resource utilization and alleviate the problem of uneven load on access points. S4: For edge users and users in blind spots who need auxiliary transmission, based on link quality, user service needs and relay availability, perform relay selection and establish a visible light relay auxiliary communication link or a radio frequency relay auxiliary communication link. In the relay selection in S4, each edge user or blind spot user may select at most one relay user to establish an auxiliary transmission relationship, and each relay user may provide forwarding services to at most one auxiliary user; for any user that needs auxiliary transmission, only one of the visible light relay link or radio frequency relay link is allowed to be selected as the auxiliary transmission mode within the same scheduling period; Among them, the relay-assisted communication link in S4 uses a relay forwarding method to complete two-hop transmission for users in the blind zone; for edge users, while retaining the direct link between them and the visible light access point, a relay-assisted link is introduced to form cooperative transmission. S5: Based on meeting the minimum rate requirements of users, optimize the power allocation of the system by combining user priority and historical contribution factors; Specifically, the power allocation of the optimization system in S5 includes: first, allocating basic power to connected users to meet the minimum service rate requirements; then, within the remaining allocable power range, performing secondary optimization allocation of power resources based on the user's current service needs, link status, cooperation relationships, and historical service conditions. S6: Perform joint iterative optimization on the user access, relay selection and power allocation results until the convergence condition is met, and then output the final resource allocation result; The joint iterative optimization process in S6 is as follows: update the relay selection relationship according to the current user access status, adjust the power allocation according to the updated relay relationship and resource occupancy, and re-evaluate the access rationality and relay cooperation effect according to the updated resource allocation result. This process is repeated until the system performance becomes stable or the preset stopping condition is met.

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