Wireless screen projection method and system integrating Bluetooth control and power supply management

Abstract

The invention relates to the technical field of Bluetooth communication, and discloses a wireless screen projection method and system integrating Bluetooth control and power supply management, and the method comprises the steps: transmitting end equipment adds preset time delay for Bluetooth data packet response according to the energy state of the transmitting end equipment, and receiving end equipment decodes the energy state by measuring the difference between round-trip response time and a reference value, and when the conditions are met, screen projection strategy adjustment negotiation is initiated and then cooperative execution is performed. According to the method, the energy state is encoded into the Bluetooth communication time sequence, so that endogenous perception and self-adaptive adjustment of the screen projection system on the power supply state are realized, the problem of screen projection interruption caused by energy state loss in a traditional scheme is fundamentally solved, and meanwhile, smooth and non-perception of image quality switching is ensured through a bidirectional negotiation mechanism, and the user experience is improved. And the reliability of wireless screen projection and the user experience are remarkably improved.

Description

Technical Field

[0001] The present invention relates to a wireless screen projection method and system integrating Bluetooth control and power supply management, belonging to the technical field of Bluetooth communication. Background Art

[0002] In the field of Bluetooth wireless screen projection technology, the existing mainstream solution adopts a one-way command-driven mode: the receiver sends control commands to the transmitter, and the transmitter continuously transmits the video stream at a fixed high quality. This mode implies a fundamental limitation - the energy state of the transmitter is regarded as an invisible variable independent of the control system. When the user conducts a business presentation or watches a long movie, the system has no perception of battery decay, resulting in a sudden interruption of screen projection when the battery is exhausted, forming a destructive cliff-like crash experience.

[0003] Despite industry attempts to optimize codecs to reduce power consumption, the core contradiction between the control link and energy status has not been resolved. This is especially true in complex electromagnetic environments (such as conference rooms with multiple Wi-Fi devices running concurrently). Channel jitter can easily be confused with energy status signals, leading to erroneous downgrade decisions. At the same time, existing technologies' blind spots in understanding user intent make it impossible to distinguish between critical content and ordinary content, resulting in a compromised experience in low-battery, high-priority scenarios.

[0004] Specifically, existing technologies face three key bottlenecks: 1. The projection system cannot sense battery degradation trends, losing its ability to proactively adjust; 2. Channel jitter and energy delay signals are difficult to distinguish, leading to misjudgments; and 3. The lack of content value dimensions causes degradation strategies to deviate from actual needs. Therefore, the technical challenges addressed by this invention are how to achieve precise energy-aware decision-making and user-intent-driven adaptive adjustments under complex operating conditions, while completely avoiding unexpected interruptions to projection services. Summary of the Invention

[0005] The present invention provides a wireless screen projection method and system that integrates Bluetooth control and power supply management. Its main purpose is to solve the risk of service interruption caused by the invisibility of energy status in the Bluetooth screen projection system, and the problem of inaccurate control decisions and disconnection from user intentions in complex environments.

[0006] To achieve the above objectives, the present invention provides a wireless screen projection method integrating Bluetooth control and power supply management, the method comprising the following steps: Step 1: The transmitting device obtains its own battery power and determines its current energy state level based on the battery power, where the energy state level includes at least two predetermined discrete levels. The transmitting device adds a corresponding predetermined delay to the Bluetooth data packet responding to the receiving device based on the energy state level, thereby encoding the energy state level into the timing of the Bluetooth communication. Step 2: The receiving device measures the round-trip response time of the Bluetooth data packet and decodes the energy state level of the transmitting device based on the delay difference between the round-trip response time and a preset reference round-trip time; Step 3: When the decoded energy state level meets the preset conditions, the receiving device sends a control message containing a screen projection strategy adjustment proposal to the transmitting device. The screen projection strategy adjustment proposal includes at least one of reducing the video stream resolution, reducing the video stream frame rate, and changing the video stream encoding bit rate. In step 4, the sending device receives the control message and responds to the screen projection strategy adjustment proposal according to its own situation. After receiving the confirmation response from the sending device, the receiving device cooperates with the sending device to perform the screen projection strategy adjustment.

[0007] Preferably, the energy state level includes a first energy state level, a second energy state level, a third energy state level and a fourth energy state level. The corresponding relationship between the delay added by the sending end device to respond to the Bluetooth data packet and the energy state level is as follows: the preset additional delay value corresponding to the first energy state level is ; The preset additional delay value corresponding to the second energy state level is ; The preset additional delay value corresponding to the third energy state level is ; The preset additional delay value corresponding to the fourth energy state level is .

[0008] Preferably, the first energy state level corresponds to a battery power of the sending device greater than 70%, the second energy state level corresponds to a battery power of the sending device between 30% and 70%, the third energy state level corresponds to a battery power of the sending device between 10% and 30%, and the fourth energy state level corresponds to a battery power of the sending device less than 10%.

[0009] Preferably, the preset benchmark round-trip time is determined at the initial stage of establishing the screen projection session, when the sending device is in a high-energy state, by measuring the round-trip response time of multiple Bluetooth data packets and averaging them; the sending device decides whether to send a confirmation response to the receiving device based on its real-time charging status and whether a charger is connected.

[0010] Preferably, after the receiving device decodes the energy state level of the sending device, and before the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the following steps are also included: when the delay difference between the round-trip response time and the preset benchmark round-trip time falls into a preset jitter fuzzy interval, the receiving device sends a timestamp packet for inquiry to the sending device; after receiving the timestamp packet for inquiry, the sending device immediately encapsulates its own receiving timestamp in a timestamp response packet and returns it to the receiving device, and when processing the timestamp packet for inquiry, the sending device does not add any preset delay related to the energy state; the receiving device calculates the pure physical round-trip time of the current channel based on the timestamp response packet and the local timestamp when receiving the timestamp response packet; the receiving device reconfirms the energy state level of the sending device based on the difference between the round-trip response time and the pure physical round-trip time.

[0011] Preferably, the sending device determines the corresponding preset delay based on the current content priority provided by the application running thereon and the energy state level, wherein the content priority includes at least one of key content, ordinary content and background content; the receiving device obtains the energy state level and content priority of the sending device at the same time by decoding the corresponding preset delay; when the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the screen projection strategy adjustment proposal is determined based on the energy state level and content priority.

[0012] Preferably, when determining the corresponding preset time delay, the transmitting end device searches according to a preset two-dimensional coding matrix based on a combination of the energy state level and the content priority to determine a unique corresponding preset time delay value.

[0013] Preferably, when the receiving device decodes that the sending device is in a low energy state level and the content priority is critical content, the screen projection strategy adjustment proposal is to maintain the current high-quality screen projection or only perform lossless compression.

[0014] Preferably, the steps of collaboratively executing the screen projection strategy adjustment include: when the receiving device sends a screen projection strategy adjustment proposal, the proposal includes the expected extension of the screen projection time based on the strategy adjustment; after the sending device confirms acceptance of the proposal, it dynamically adjusts its video stream transmission parameters to match the new screen projection strategy, including but not limited to reducing the video encoding bit rate or adopting a more efficient codec; the receiving device synchronously adjusts its video decoding and display parameters to seamlessly adapt to changes in the transmission parameters of the sending device.

[0015] A wireless screen projection system integrating Bluetooth control and power supply management, the system comprising: The transmitting device is configured with: an energy state sensing module for obtaining the battery power of the transmitting device and determining the current energy state level, wherein the energy state level includes at least two preset discrete levels; a delay encoding module for adding a corresponding preset delay to the Bluetooth data packet responding to the receiving device based on the energy state level, so as to encode the energy state level into the timing of the Bluetooth communication; and a response processing module for receiving the control message sent by the receiving device and responding to the screen projection strategy adjustment proposal based on its own situation; The receiving device is configured with: a round-trip time measurement module for measuring the round-trip response time of a Bluetooth data packet; a delay decoding module for decoding the energy state level of the sending device based on the delay difference between the round-trip response time and a preset benchmark round-trip time; a policy negotiation module for sending a control message containing a screen projection strategy adjustment proposal to the sending device when the decoded energy state level meets the preset conditions, the screen projection strategy adjustment proposal including at least one of reducing the video stream resolution, reducing the video stream frame rate, and changing the video stream encoding bit rate; and a collaborative execution module for collaboratively executing the screen projection strategy adjustment with the sending device after receiving a confirmation response from the sending device.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By converting the battery status of the transmitter into a micro-disturbance of the Bluetooth communication timing, energy information can be integrated into the control link in real time without an independent transmission channel; the receiver synchronously perceives the energy state change by analyzing the difference between the timing change and the preset benchmark; this mechanism upgrades the Bluetooth communication timing from a simple data carrier to an energy state transmission medium. While maintaining protocol compatibility, the projection system has the ability to inherently perceive the energy situation for the first time, thereby avoiding the risk of projection interruption caused by loss of energy status in traditional solutions.

[0017] 2. When sensing a change in energy status, the receiving end proactively initiates a negotiation proposal containing specific degradation parameters. The sending end responds and confirms it based on the charging status and application scenario. Based on the negotiation results, both parties synchronously adjust the codec strategy, making the image quality switching process smooth and imperceptible. This paradigm shift from one-way instructions to two-way negotiation transforms the forced interruption at the energy critical point into a controllable service quality transition, ensuring the continuity of core tasks in high-value scenarios such as business presentations. Furthermore, the closed-loop verification logic of timestamp query packets and instant responses is introduced. By comparing the difference between the baseline round-trip time and the pure channel delay, the interference of physical jitter on the energy delay signal is accurately removed. This mechanism enables the system to distinguish between active delay coding and passive channel fluctuations in complex electromagnetic environments, ensuring the reliability of energy status judgment decisions even under extreme conditions such as Wi-Fi co-channel interference, significantly improving the robustness margin of the main solution.

[0018] 3. The transmitter encodes the application layer content priority (critical / normal / background) and energy status in two dimensions, and synchronously transmits the physical state and user intent through a single timing disturbance signal. The receiver generates scenario-based degradation strategies based on this, such as maintaining lossless image quality in low-battery, high-priority scenarios. This cross-layer information fusion mechanism enables the system to upgrade from a mechanical response driven by power to intelligent decision-making driven by value, achieving the essential unity of technical optimization and user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an illustration of the preset response delay matrix for the joint mapping of energy level and content priority of the present invention; Figure 2 Schematic diagram of the relationship between the preset additional delay, energy state level and content priority of the present invention; Figure 3 This is a timing diagram of the collaborative switching process between the timestamp query mechanism and the high-quality screen projection strategy of the present invention; Figure 4 This is a comparison chart of the improvement effect of enabling the query mechanism of the present invention on the recognition accuracy under different channel jitter intensities.

[0020] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0021] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The present invention provides a wireless screen projection method integrating Bluetooth control and power management, the method comprising the following steps: Step 1: The transmitting device obtains its own battery power and determines its current energy state level based on the battery power, where the energy state level includes at least two predetermined discrete levels. The transmitting device adds a corresponding predetermined delay to the Bluetooth data packet responding to the receiving device based on the energy state level, thereby encoding the energy state level into the timing of the Bluetooth communication. Step 2: The receiving device measures the round-trip response time of the Bluetooth data packet and decodes the energy state level of the transmitting device based on the delay difference between the round-trip response time and a preset reference round-trip time; Step 3: When the decoded energy state level meets the preset conditions, the receiving device sends a control message containing a screen projection strategy adjustment proposal to the transmitting device. The screen projection strategy adjustment proposal includes at least one of reducing the video stream resolution, reducing the video stream frame rate, and changing the video stream encoding bit rate. In step 4, the sending device receives the control message and responds to the screen projection strategy adjustment proposal according to its own situation. After receiving the confirmation response from the sending device, the receiving device cooperates with the sending device to perform the screen projection strategy adjustment.

[0023] Preferably, the energy state level includes a first energy state level, a second energy state level, a third energy state level and a fourth energy state level. The corresponding relationship between the delay added by the sending end device to respond to the Bluetooth data packet and the energy state level is as follows: the preset additional delay value corresponding to the first energy state level is ; The preset additional delay value corresponding to the second energy state level is ; The preset additional delay value corresponding to the third energy state level is ; The preset additional delay value corresponding to the fourth energy state level is .

[0024] Preferably, the first energy state level corresponds to a battery power of the sending device greater than 70%, the second energy state level corresponds to a battery power of the sending device between 30% and 70%, the third energy state level corresponds to a battery power of the sending device between 10% and 30%, and the fourth energy state level corresponds to a battery power of the sending device less than 10%.

[0025] Preferably, the preset benchmark round-trip time is determined at the initial stage of establishing the screen projection session, when the sending device is in a high-energy state, by measuring the round-trip response time of multiple Bluetooth data packets and averaging them; the sending device decides whether to send a confirmation response to the receiving device based on its real-time charging status and whether a charger is connected.

[0026] Preferably, after the receiving device decodes the energy state level of the sending device, and before the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the following steps are also included: when the delay difference between the round-trip response time and the preset benchmark round-trip time falls into a preset jitter fuzzy interval, the receiving device sends a timestamp packet for inquiry to the sending device; after receiving the timestamp packet for inquiry, the sending device immediately encapsulates its own receiving timestamp in a timestamp response packet and returns it to the receiving device, and when processing the timestamp packet for inquiry, the sending device does not add any preset delay related to the energy state; the receiving device calculates the pure physical round-trip time of the current channel based on the timestamp response packet and the local timestamp when receiving the timestamp response packet; the receiving device reconfirms the energy state level of the sending device based on the difference between the round-trip response time and the pure physical round-trip time.

[0027] Preferably, the sending device determines the corresponding preset delay based on the current content priority provided by the application running thereon and the energy state level, wherein the content priority includes at least one of key content, ordinary content and background content; the receiving device obtains the energy state level and content priority of the sending device at the same time by decoding the corresponding preset delay; when the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the screen projection strategy adjustment proposal is determined based on the energy state level and content priority.

[0028] Preferably, when determining the corresponding preset time delay, the transmitting end device searches according to a preset two-dimensional coding matrix based on a combination of the energy state level and the content priority to determine a unique corresponding preset time delay value.

[0029] Preferably, when the receiving device decodes that the sending device is in a low energy state level and the content priority is critical content, the screen projection strategy adjustment proposal is to maintain the current high-quality screen projection or only perform lossless compression.

[0030] Preferably, the steps of collaboratively executing the screen projection strategy adjustment include: when the receiving device sends a screen projection strategy adjustment proposal, the proposal includes the expected extension of the screen projection time based on the strategy adjustment; after the sending device confirms acceptance of the proposal, it dynamically adjusts its video stream transmission parameters to match the new screen projection strategy, including but not limited to reducing the video encoding bit rate or adopting a more efficient codec; the receiving device synchronously adjusts its video decoding and display parameters to seamlessly adapt to changes in the transmission parameters of the sending device.

[0031] A wireless screen projection system integrating Bluetooth control and power supply management, the system comprising: The transmitting device is configured with: an energy state sensing module for obtaining the battery power of the transmitting device and determining the current energy state level, wherein the energy state level includes at least two preset discrete levels; a delay encoding module for adding a corresponding preset delay to the Bluetooth data packet responding to the receiving device based on the energy state level, so as to encode the energy state level into the timing of the Bluetooth communication; and a response processing module for receiving the control message sent by the receiving device and responding to the screen projection strategy adjustment proposal based on its own situation; The receiving device is configured with: a round-trip time measurement module for measuring the round-trip response time of the Bluetooth data packet; a delay decoding module for decoding the energy state level of the sending device according to the delay difference between the round-trip response time and a preset reference round-trip time; a policy negotiation module for sending a control message containing a screen projection strategy adjustment proposal to the sending device when the decoded energy state level meets the preset conditions, the screen projection strategy adjustment proposal including at least one of reducing the video stream resolution, reducing the video stream frame rate and changing the video stream encoding bit rate; and a collaborative execution module for collaboratively executing the screen projection strategy adjustment with the sending device after receiving the confirmation response from the sending device; at the same time, it is necessary to say It is clear that the screen projection strategy adjustment mechanism proposed in the present invention is not mandatory and automatically executed, but is based on the real-time status perception of the sending device and the collaborative judgment of the receiving device, and is combined with whether it is currently in charging status, content priority and user configuration strategy to make a comprehensive decision. For example, in system design, the sending device is allowed to actively ignore some degradation suggestions when it detects that an external charger is connected, so as to maintain a high-quality screen projection experience; at the same time, it also supports users to independently set whether to enable the energy state-driven dynamic adjustment function through application layer configuration, thereby ensuring service continuity while retaining the user's control over the image quality performance. These are all extended implementation methods that can be known to ordinary technicians in this field.

[0032] Example 1: In this embodiment, the transmitting device first obtains its own battery power and determines its current energy state level based on the power value. In a specific implementation, the energy state level is divided into four preset discrete levels, corresponding to the battery power greater than 70%, between 30% and 70%, between 10% and 30%, and less than 10%. For each energy state level, the system presets a corresponding additional response delay value, which is recorded as 、 、 and When the transmitting device responds to the receiving device's Bluetooth data packet, this additional delay is superimposed on the normal response delay, forming a coded signal embedded in the timing of the Bluetooth communication. The receiving device measures the round-trip response time of the data packet and compares it with the baseline round-trip time obtained by multiple measurements and averaging at the beginning of the session (i.e., when the transmitting device is in a high energy state). The difference between the two is decoded to obtain the corresponding preset additional delay value, thereby identifying the current energy state level of the transmitting device. Given that channel jitter caused by electromagnetic interference in actual Bluetooth communication environments may interfere with the delay decoding results, the present invention further introduces a timestamp query and response mechanism. When the receiving device determines that the difference between the current round-trip delay and the baseline time falls within a preset fuzzy jitter interval, making it difficult to clearly identify the energy state level, the receiving device will send a timestamp packet for query to the transmitting device. After receiving the query request, the transmitting device immediately encapsulates its received timestamp to generate a timestamp response packet and transmits it back. No additional delay related to the energy state is added during the response process. The receiving device determines the energy state level based on the local timestamp of the received response packet and the transmitting device time it carries. The pure physical round-trip time of the current channel is calculated by stamping, and the non-coding delay component caused by channel disturbance is further stripped away based on this, so as to achieve more accurate confirmation of the energy state level; when the energy state level obtained by decoding meets the specific screen projection strategy adjustment conditions, the receiving end will actively send a control message containing an adjustment proposal to the sending end. The control message may include a suggestion to adjust at least one of the video stream resolution, frame rate and encoding bit rate. After receiving the control message, the sending end will determine whether to respond to the adjustment proposal based on the current charging status and the content priority indicated by the running application, and will work with the receiving end to complete the parameter adjustment after confirming acceptance.

[0033] In order to support the above-mentioned screen projection strategy adjustment mechanism based on content priority as an auxiliary judgment basis, the sender considers its energy state level and the priority of the current content when setting the additional response delay. The priority in the system may include predefined categories such as key content, ordinary content and background content. The sender determines the unique additional response delay value based on the combination of energy state level and content priority by searching the preset two-dimensional coding matrix, and completes the encoding of the two-dimensional status information accordingly. The receiving end can simultaneously obtain the energy state level and content priority of the sender while decoding the response delay, thereby generating more accurate strategy adjustment suggestions based on the scene information jointly constituted by the two, for example In scenarios where the battery is low and the content priority is critical, the system can choose to maintain the current high-quality screen projection state or only perform lossless compression to ensure that the display quality of the core information is not affected; at the same time, to ensure that the policy adjustment process has good controllability and execution consistency, the receiving end can also attach an expected screen projection delay adjustment amount in its control message, and the sending end dynamically adjusts the video encoding parameters based on the prompt information, including but not limited to reducing the video encoding bit rate or replacing it with a more efficient codec. At the same time, the receiving end synchronously adjusts its own video decoding and display parameters, thereby maintaining parameter coordination with the sending end, and ensuring the playback continuity and picture consistency of the video stream during the adjustment process.

[0034] Example 2: During the initialization phase of a complete screen projection session, the sending device obtains the current battery power through the battery status acquisition module, and divides the energy status into levels according to the power value. Specifically, the power value greater than 70% is set as the first energy level, between 30% and 70% is the second energy level, between 10% and 30% is the third energy level, and below 10% is set as the fourth energy level. The system presets a corresponding additional response delay value for each level. This delay value will be superimposed on the normal response delay when the sending device responds to the Bluetooth data packet sent by the receiving end, so as to embed status information in the communication timing. The setting of this additional delay value fully considers the actual physical response characteristics of the Bluetooth link, ensuring that the delay difference between the levels is sufficient to be effectively distinguished by the receiving device under stable channel conditions, and will not trigger the communication retry mechanism of the Bluetooth link layer.

[0035] The response delay coding module introduces a preset additional response delay when responding after receiving the receiving end data packet according to the current energy state level, so as to realize the coding transmission of energy state information to the link layer. In order to ensure the availability of the system in the scenario of Bluetooth link fluctuation or external interference, the setting of the delay value takes into account both communication stability and discriminability. Generally, the difference in additional response delay between at least two energy levels should be greater than twice the average link delay jitter to ensure that the system has the robustness of discrimination in actual deployment environment. In order to improve the determination accuracy of energy state decoding, especially when there is the influence of physical channel fluctuation, this embodiment further introduces a set of timestamp query and response mechanisms. When the receiving end device detects the current When the difference between the round-trip response delay of the data packet and the benchmark average value counted in the initialization phase falls into the set fuzzy interval, which should be determined based on the typical fluctuation range of the Bluetooth physical layer, a timestamp query packet for confirmation will be actively sent to the sending device. After receiving the query request, the sending device will immediately encapsulate the current local receiving time to generate a timestamp response packet and return it, while ensuring that no additional response delay is introduced in the response process. The receiving end calculates the round-trip time of the physical link by comparing the locally recorded receiving time with the sending timestamp carried in the response packet, thereby removing the influence of the physical layer link uncertainty factors on the judgment result from the overall delay, and realizing accurate restoration of the energy state level.

[0036] After the energy state level is effectively decoded, the receiving end will enter the screen projection strategy decision stage. In order to achieve a more context-aware strategy judgment, the sending end device extracts the type information of the current screen projection content in each communication response cycle through the application content recognition module. The content information is identified and classified based on the media content metadata provided by the application running in the device. Typical classifications include key content, ordinary content and background content. The system uses the content priority information and the current energy state level as input, and searches for the preset two-dimensional response delay coding matrix to determine the unique additional delay value for this round of response. When the receiving end decodes the delay, it can synchronously obtain The current energy status and content priority of the sending device provide accurate context information support for the subsequent control strategy generation; based on the decoding results, the receiving device generates a control message including projection parameter adjustment suggestions through the control message generation module. Specific suggestions include reducing video resolution, reducing video frame rate, adjusting video encoding bit rate, or switching to a more efficient encoding and decoding algorithm. For scenarios with a combination of key content and low energy status levels, the system can choose to maintain high-quality projection status or adopt a lossless compression strategy to ensure information integrity. In the control message, the receiving end can also attach the expected projection time delay change as a reference benchmark for the subsequent synchronous adjustment of video parameters of both parties. After receiving the control message, the sending device's response processing module will respond based on the current charging status and content priority information. If no external power supply is currently connected, the system will give priority to the parameter optimization method recommended in the control message, such as switching the original encoding method from H.264 to HEVC, or adjusting the frame rate from 30 frames per second to 20 frames per second, or lowering the video resolution to high-definition levels. The adjustment will take effect at the key frame refresh point in the current encoding group, and the adjustment confirmation information will be fed back through the Bluetooth link. After receiving the adjustment confirmation information, the receiving device will switch to the corresponding video parameter configuration through the video decoding scheduling module, and synchronously update the decoding strategy from the next key frame to ensure that the entire video stream remains continuously played during the parameter change process, avoiding abnormal phenomena such as stuttering or screen tearing.

[0037] Example 3: This example is carried out in a test platform that simulates a typical application scenario, and aims to illustrate the specific operating process of the present invention in an interference environment, the basis for setting parameters and its technical effects; the test platform consists of a laptop computer as a sending device and a wireless screen projection receiver as a receiving device, both of which have Bluetooth communication functions. In order to simulate the complex electromagnetic environment that may be encountered in actual use, the test is carried out under the condition that there are multiple Wi-Fi networks and other Bluetooth devices working concurrently; in the initial stage of establishing a screen projection session, in order to establish a stable and reliable benchmark round-trip time, the sending device needs to be in a high-energy state, for example, when the battery is fully charged and connected to an external power supply, under this condition, by measuring the round-trip response time of multiple Bluetooth data packets from the receiving device to the receipt of the confirmation response from the sending device, and averaging the measured series of time values, it can be determined A baseline round-trip time is established, serving as the zero-point reference for all subsequent delay decoding operations. Its proper setting is essential for accurate energy state determination. For example, a baseline value obtained under specific test conditions can be 4.8 milliseconds. Based on this baseline, this embodiment further describes a two-dimensional encoding mechanism for energy state levels and additional delays. The core of this mechanism lies in constructing a two-dimensional encoding matrix. The matrix's setting must strike a technical balance between the timeliness of state change perception and the stability of Bluetooth link communication. If the increment of the additional delay value is too small, it will be difficult to distinguish from noise in the presence of channel jitter, potentially leading to misjudgment of energy state. Conversely, if the delay value is too large, it may exceed the normal response range allowed by the Bluetooth protocol, triggering unnecessary communication retries. Therefore, the additional delay value can be set as a non-arithmetic sequence, using larger delay increments at lower energy state levels to achieve clearer state distinction. See Table 1: Preset additional response delay encoding table corresponding to energy state level and content priority.

[0038] In a continuous screen projection application, the sending device is battery-powered, and its power level changes from high to low. When its battery level drops to 25%, it enters the third energy state level, and the current screen projection content is a presentation identified by the application as key content. The delay encoding module of the sending device will add a preset delay of 10 milliseconds when responding to the receiving data packet based on the aforementioned matrix. The round-trip time measured by the round-trip time measurement module of the receiving device, after deducting the baseline value of 4.8 milliseconds, obtains a delay difference of approximately 10 milliseconds. Based on this, the delay decoding module can decode that the current combined state of the sending device is the third energy state level and key content.

[0039] Taking into account the impact of channel jitter on delay measurement in practical applications, the present invention introduces a timestamp query mechanism. When the delay difference measured by the receiving end falls into a preset jitter ambiguity interval, for example, the value is between two coded delay values, which makes the state judgment ambiguous, the query mechanism can be activated at this time. The receiving end sends a timestamp packet for query to the sending end. After receiving the timestamp packet, the sending end immediately encapsulates its own receiving timestamp in the timestamp response packet and returns it, and does not add any preset delay related to the energy state in the response process. The receiving end can calculate the pure physical round-trip time of the current channel by comparing the local time with the timestamp in the response packet, and subtract this pure physical round-trip time from the total round-trip response time to remove the channel jitter interference and obtain a more accurate additional delay value actively encoded by the sending end, thereby realizing accurate confirmation of the energy state level of the sending end; after effectively decoding the state of the sending end, the system will enter the negotiation and adjustment stage of the screen projection strategy, with the aforementioned third energy state level and the scenario of key content For example, the policy negotiation module of the receiving device can generate a screen projection strategy adjustment proposal containing specific parameters, such as recommending adjusting the video stream resolution from 1080p to 720p, maintaining a frame rate of 30fps to ensure the clarity of key content, and moderately lowering the video encoding bit rate. The control message is received by the sender through the Bluetooth link. The response processing module of the sending device confirms the proposal based on its current status that it is not connected to the charger, and indicates the video frame position where the parameter adjustment will take effect in its response information; then, the sender starts to use the new video stream transmission parameters at the next video encoding key frame refresh point. After receiving the confirmation information, the collaborative execution module of the receiving end also synchronously adjusts its decoding and display parameters to ensure seamless switching when the next key frame arrives, thereby achieving a smooth transition in the user's visual perception and avoiding abnormal phenomena such as black screen, freeze or screen tearing. This collaborative process effectively extends the available screen projection time of the remaining power while ensuring the continuity of the core tasks.

[0040] Example 4: This example combines Figures 1 to 4 , a wireless screen projection method and system integrating Bluetooth control and power management is described. Figure 1 As shown, the energy levels listed vertically on the left include the first level (>70%), the second level (30%~70%), the third level (10%~30%) and the fourth level (<10%); the three content priorities of key content, general content and background content are listed horizontally at the top. The preset additional response delay value set for the corresponding combination is displayed in the cross cells of the matrix, with the specific value indicated in brackets in milliseconds (ms), including 、 、 、 、 、 、 、 、 and ,in to Represents the benchmark additional response delay values ​​under four discrete energy state levels. In addition, the exemplary coding points are highlighted in the figure with dotted circles and arrows. The example scenario annotation box is used to supplement the system status corresponding to this point, namely, power: 25%, content: key content, and encoding delay: 10ms. The positioning logic and preset response delay configuration of this specific state combination in the two-dimensional coding matrix are clearly displayed, thereby realizing the system's synchronous perception and linkage response to the energy status level and user intention (reflected by content priority).

[0041] like Figure 2 As shown, the horizontal axis is the energy status level, including the first level (>70%), the second level (30%~70%), the third level (10%~30%) and the fourth level (<10%); the vertical axis is the preset additional delay (milliseconds), which is used to encode the above status information by means of additional response delay in Bluetooth communication. Three curves are drawn in the figure, corresponding to different content priorities. The solid line curve and the dots marked in the legend represent key content, the dotted line curve and the square mark represent ordinary content, and the dot-dash line curve and the diamond mark represent background content. As the energy status level changes from high to low, the preset additional delay (milliseconds) shows a significant upward trend in the three types of content priorities. Especially in the fourth level (<10%) critical power state, a higher additional delay is set for each type of content to enhance the distinction of the status signal.

[0042] like Figure 3 As shown, the process starts with the receiving device responding to the Bluetooth data packet, and after measuring the round-trip delay falling into the jitter ambiguity interval, it triggers the sending of a timestamp packet for inquiry. After receiving the inquiry request, the sending device immediately returns a response without additional delay as a return timestamp response packet. The receiving device accurately calculates the pure physical round-trip time based on the response packet, thereby completing the channel interference stripping, and confirms that the sending end combination state is: the fourth energy state level and key content. The receiving end then sends a control message containing a proposal to maintain high quality. The response processing module of the sending end accepts the proposal based on its own state. The sending end further sends a confirmation response and indicates the effective video frame position. At the next video encoding key frame refresh point, it executes the transmission of the video stream encoded with the new parameters and indicates that the sending end has switched to the new parameters. At the same time, the receiving end synchronously switches the decoding parameters for seamless playback, achieving a smooth transition to a high-quality projection strategy. And as Figure 4As shown in the figure, the accuracy of the system in identifying energy states under different channel jitter intensities is demonstrated. The solid line represents the accuracy without the timestamp query mechanism, and the dotted line represents the accuracy after the timestamp query mechanism is enabled. The results show that the timestamp query mechanism significantly improves the recognition accuracy in high jitter environments, from 60% to over 95%.

[0043] Example 5: In a high-density conference scenario, there are multiple wireless LAN access points and multiple Bluetooth devices running at the same time. The system needs to dynamically adapt to changes in the battery power of the sending device while ensuring the integrity of the video content transmission. In this scenario, the sending device is a portable terminal with Bluetooth communication capabilities. Its current battery power is 45%. The running application is a type of multimedia presentation tool. The played content is identified as a key content type; the sending device obtains the current battery power reading through its internal battery status perception module, and maps the power to the second energy state level accordingly. At the same time, the content recognition module identifies that the currently played content belongs to the key content category by analyzing the metadata fields provided in the application layer interface, including parameters such as media type, current window focus state and user operation behavior. After completing After the above identification, the sender searches for a preset two-dimensional response delay coding matrix. The matrix uses energy state level as row index and content priority level as column index. Each cell in the matrix corresponds to a unique additional response delay value. The coding matrix is ​​pre-set during the system initialization phase. Its generation principle is based on the link jitter tolerance characteristics known in the art and the technical constraints of the Bluetooth protocol layer on delay tolerance, and is constructed through engineering modeling. Specifically, it includes the following design basis: The setting of the additional response delay value needs to establish an engineering-acceptable balance between state judgment clarity and communication stability. If the delay difference between adjacent levels is too small, it may lead to increased uncertainty in the state decoding results under channel noise fluctuation conditions; if the difference is set too large, it may interfere with the protocol layer's normal control of the response time limit, causing retransmission or connection interruption at the communication layer. Therefore, each additional response delay value in the matrix must meet the following requirements: in any two adjacent energy state levels, the difference in additional delay under the same content priority should be greater than twice the link jitter range to enhance decoding robustness; in the same energy state level, the additional delay values ​​corresponding to different content priorities should be at least one millisecond apart to ensure the decoding resolution of content priority differentiation; the maximum additional response delay in the overall matrix should be in a safe range below the maximum tolerable response delay threshold defined by the Bluetooth protocol.

[0044] In this example, since the current state combination is the second energy state level and the key content priority, the corresponding additional response delay value is six milliseconds. The additional response delay is inserted by the link layer delay control module of the transmitter during the response data packet generation process, forming a control delay with coding significance within the response time window; after the receiving device receives the response data packet, it calculates the total round-trip response time of the data packet through its round-trip time measurement module, and deducts the previously established benchmark round-trip time from the response time. The benchmark round-trip time is obtained by the transmitter at the first energy state level through multiple interactive sampling in the initialization phase. Its statistical average value, for example, is four point eight milliseconds. The resulting net response delay is six milliseconds. The receiver checks the value based on the stored coding matrix to determine that the current state combination is the second energy state level and the key content priority; at the same time, in order to improve the stability of the judgment In order to improve the performance and fault tolerance, the system sets a fuzzy jitter interval. The upper and lower limits of the interval are determined by the statistical data of the historical round-trip delay fluctuations of the link, and are automatically updated according to the dynamic fluctuations during operation. For example, the current fuzzy interval is set to plus or minus one and a half milliseconds. If the measured net response delay falls into the overlapping interval corresponding to two legal additional delay values, the judgment result will not take effect temporarily, and the receiving end will start the timestamp query process for confirmation. Specifically, the receiving end sends a data packet containing a local sending timestamp field. After receiving the data packet, the sending end immediately adds the receiving timestamp field and returns it without introducing additional response delay. The receiving end calculates the pure physical round-trip time based on the two timestamp fields in the response packet, thereby obtaining a reference delay that is not affected by coding disturbances, which is further used to assist in verifying the previous coding judgment result. If it is found that the deviation exceeds the tolerance range, the original state judgment is corrected, otherwise it remains unchanged.

[0045] After the state identification is completed, the policy negotiation module of the receiving end forms a set of projection parameter adjustment suggestions based on the currently identified second energy state level and key content category, combined with the system operation strategy generation module. The suggestion includes the following adjustment items: adjust the current video resolution from full HD standard to 720-line HD format, maintain the frame rate at 30 frames per second, and reduce the encoding bit rate by about 20%. The generation of this adjustment strategy takes into account the following technical factors: Under the premise of ensuring the visual quality of key content, parameter adjustment is performed without changing the encoder type, which can effectively reduce system resource consumption and computing burden, and avoid additional energy consumption pressure. This optimization idea is based on the hardware support capabilities of existing mainstream devices for specific encoding standards, without causing increased processing delays. The projection parameter changes are completed under the premise of the sending end receiving the above parameter adjustment suggestions, and its response processing module makes a judgment based on the local operation status judgment result (currently in the power-off state), and confirms that the above adjustment plan is acceptable under the current conditions. On the premise of judging that the response conditions are met, the sending end notifies the receiving end through the confirmation response information that the adjustment plan has been adopted, and indicates that the parameter change will take effect at the next key frame refresh time. Subsequently, before the next key frame is generated, the sending end updates the encoder configuration parameters so that subsequent key frames are encoded and sent according to the new set format; at the same time, after receiving the confirmation response, the receiving end updates the relevant parameter configuration of the decoding module to ensure smooth synchronization when the key frame switches, and to ensure that the picture continuity and content consistency are not affected. Therefore, this embodiment realizes the state coding identification and policy dynamic adjustment process based on two-end collaboration in scenarios where the Bluetooth communication link conditions are complex and the power is constantly changing, taking into account both user experience and resource optimization goals, and has good feasibility and deployment adaptability in typical engineering environments.

[0046] Example 6: In an intelligent conference interaction scenario involving multiple Bluetooth devices running concurrently and channel states changing dynamically, the transmitting device is a portable tablet terminal with Bluetooth communication capabilities, and the receiving device is a wireless receiving module with image decoding and display functions. In this scenario, the transmitting device determines its energy state level and content priority category based on its internal battery power status and the type of application being run. The energy state level is divided into four preset levels based on the device battery power, corresponding to power levels above 70%, between 30% and 70%, between 10% and 30%, and below 10%; the content priority is divided into key content, ordinary content, and background content based on the attributes of the presented media content.

[0047] In this embodiment, to further enhance the discriminability of the additional response delay and the stability of signal recognition, the transmitting device obtains the corresponding additional response delay value by searching a system-preset two-dimensional coding matrix based on the current energy state level and content priority. The construction of this matrix refers to the typical delay jitter amplitude distribution characteristics of the Bluetooth communication link, and sets the minimum difference between adjacent delay values ​​to be greater than twice the link jitter standard deviation to prevent the superposition error of the response delay from falling into the fuzzy interval. At the same time, when designing this matrix, it is ensured that the delay values ​​of different rows in any column meet the discrimination redundancy, and the delay values ​​corresponding to different columns in any row are also distinguishable. This ensures that changes in content priority or energy status level can be uniquely mapped and identified through the additional response delay; when the sending device responds to the Bluetooth data packet of the receiving device, the additional response delay is introduced into its response process. This delay is implemented within the system through the delay control mechanism of the lower layer of the Bluetooth protocol stack, and does not modify the time slot structure defined by the Bluetooth protocol. Instead, it delays the response triggering timing through software. To ensure that the addition of this delay does not trigger the triggering of the communication protocol retransmission mechanism, the maximum value of the additional response delay is always within the maximum time limit of the Bluetooth link layer confirmation response, so as to avoid affecting the link establishment and data interaction stability. After receiving the response packet, the receiving device records the current round-trip response time through its local time measurement module, and calculates the difference based on the benchmark response time established in the initialization phase. The benchmark response time is obtained by continuous multiple measurements and taking the average value during the initialization phase of the screen projection session, when the sending device has sufficient power and the system is stable. In this embodiment, when the difference falls within the judgment interval set by the system, the receiving device reversely finds the energy state level and content priority of the sending end based on the known coding matrix; if the calculated response delay difference is in the overlapping area between two possible coding delays, or the receiving device detects that the historical response time of the current link of the system shows an obvious fluctuation trend, the receiving device Immediately enter the query confirmation process, which triggers the timestamp response behavior of the sending device by sending a specific query timestamp packet. After receiving the query timestamp packet, the sending device immediately records the receiving timestamp and encapsulates it into the response data packet and returns it to the receiving device. No additional response delay is introduced in this process. The receiving end compares the local sending timestamp with the received return timestamp, calculates the pure physical round-trip time of the link, and deducts this physical round-trip time from the measured total response delay, and finally obtains the additional response delay component introduced by the active encoding of the sending end. Therefore, the receiving end can perform secondary confirmation on the recognition of the energy state level and content priority, thereby improving the recognition robustness of the system in electromagnetic interference environment.

[0048] Based on the stable recognition results, if the receiver determines that the sender is currently in a lower energy state level and the content priority is not critical, the receiver will construct a control message containing screen projection strategy adjustment parameters. These parameters include but are not limited to video resolution, frame rate, and encoding bitrate adjustment suggestions. The control message may also carry an expected video response delay adjustment value to prompt the sender to adjust the synchronization rhythm of the video stream during the parameter switching process. After receiving this control message, the sender decides whether to accept the strategy adjustment based on its current charging status and the recognition results of the current content type by the application registered in the operating system. The sender will identify the keyframe position where the adjustment takes effect in the response. The sender then initiates the encoding parameter update operation at the specified keyframe point. The parameter adjustment will be completed before the generation of a new keyframe in the current encoding group. The updated content includes the resolution setting, the bitrate cap, and the possible encoding algorithm type to be used (such as switching from H.264 to HEVC). At the same time, after receiving the confirmation response, the receiver also synchronously modifies the decoder parameter configuration and completes the decoding parameter update at the upcoming keyframe to ensure smooth and continuous video images.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wireless screen projection method integrating Bluetooth control and power supply management, characterized in that: The method comprises the following steps: Step 1: The transmitting device obtains its own battery power and determines its current energy state level based on the battery power, where the energy state level includes at least two predetermined discrete levels. The transmitting device adds a corresponding predetermined delay to the Bluetooth data packet responding to the receiving device based on the energy state level, thereby encoding the energy state level into the timing of the Bluetooth communication. Step 2: The receiving device measures the round-trip response time of the Bluetooth data packet and decodes the energy state level of the transmitting device based on the delay difference between the round-trip response time and a preset reference round-trip time; Step 3: When the decoded energy state level meets the preset conditions, the receiving device sends a control message containing a screen projection strategy adjustment proposal to the transmitting device. The screen projection strategy adjustment proposal includes at least one of reducing the video stream resolution, reducing the video stream frame rate, and changing the video stream encoding bit rate. In step 4, the sending device receives the control message and responds to the screen projection strategy adjustment proposal according to its own situation. After receiving the confirmation response from the sending device, the receiving device cooperates with the sending device to perform the screen projection strategy adjustment.

2. A wireless screen projection method integrating Bluetooth control and power supply management according to claim 1, characterized in that: The energy state level includes the first energy state level, the second energy state level, the third energy state level and the fourth energy state level. The corresponding relationship between the delay added by the sending end device to respond to the Bluetooth data packet and the energy state level is as follows: The preset additional delay value corresponding to the first energy state level is ; The preset additional delay corresponding to the second energy state level is ; The preset additional delay corresponding to the third energy state level is ; The preset additional delay value corresponding to the fourth energy state level is .

3. A wireless screen projection method integrating Bluetooth control and power supply management according to claim 2, characterized in that: The first energy state level corresponds to a battery level greater than 70% on the sending device, the second energy state level corresponds to a battery level between 30% and 70% on the sending device, the third energy state level corresponds to a battery level between 10% and 30% on the sending device, and the fourth energy state level corresponds to a battery level less than 10% on the sending device.

4. The wireless screen projection method integrating Bluetooth control and power supply management according to claim 1, characterized in that: The preset benchmark round-trip time is determined at the beginning of the screen projection session, when the sending device is in a high-energy state, by measuring the round-trip response time of multiple Bluetooth data packets and averaging them. The sending device decides whether to send a confirmation response to the receiving device based on its actual charging status and whether a charger is connected.

5. The wireless screen projection method integrating Bluetooth control and power supply management according to claim 1, characterized in that: After the receiving device decodes the energy state level of the sending device, and before the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the following steps are also included: when the delay difference between the round-trip response time and the preset benchmark round-trip time falls into a preset jitter fuzziness interval, the receiving device sends a timestamp packet for inquiry to the sending device; after receiving the timestamp packet for inquiry, the sending device immediately encapsulates its own receiving timestamp in a timestamp response packet and returns it to the receiving device, and when processing the timestamp packet for inquiry, the sending device does not add any preset delay related to the energy state; the receiving device calculates the pure physical round-trip time of the current channel based on the timestamp response packet and the local timestamp when receiving the timestamp response packet; the receiving device reconfirms the energy state level of the sending device based on the difference between the round-trip response time and the pure physical round-trip time.

6. The wireless screen projection method integrating Bluetooth control and power management according to claim 1, characterized in that: The sending device determines the corresponding preset delay based on the current content priority provided by the application running on it and the energy state level, where the content priority includes at least one of key content, ordinary content and background content; the receiving device decodes the corresponding preset delay and simultaneously obtains the energy state level and content priority of the sending device; when the receiving device sends a control message containing a screen projection strategy adjustment proposal to the sending device, the screen projection strategy adjustment proposal is determined based on the energy state level and content priority.

7. A wireless screen projection method integrating Bluetooth control and power supply management according to claim 6, characterized in that: When determining the corresponding preset delay, the transmitting end device searches according to the combination of the energy state level and the content priority according to the preset two-dimensional coding matrix to determine the unique corresponding preset delay value.

8. The wireless screen projection method integrating Bluetooth control and power supply management according to claim 6, characterized in that: When the receiving device decodes that the sending device is in a low energy state level and the content priority is critical content, the screen projection strategy adjustment proposal is to maintain the current high-quality screen projection or only perform lossless compression.

9. The wireless screen projection method integrating Bluetooth control and power supply management according to claim 1, characterized in that: The steps of collaboratively executing the screen projection strategy adjustment include: when the receiving device sends a screen projection strategy adjustment proposal, the proposal includes the expected extension of the screen projection time based on the strategy adjustment; after the sending device confirms acceptance of the proposal, it dynamically adjusts its video stream transmission parameters to match the new screen projection strategy, including but not limited to reducing the video encoding bit rate or adopting a more efficient codec; the receiving device synchronously adjusts its video decoding and display parameters to seamlessly adapt to changes in the transmission parameters of the sending device.

10. A wireless screen projection system integrating Bluetooth control and power supply management, characterized in that: The system comprises: The transmitting device is configured with: an energy state sensing module for obtaining the battery power of the transmitting device and determining the current energy state level, wherein the energy state level includes at least two preset discrete levels; a delay encoding module for adding a corresponding preset delay to the Bluetooth data packet responding to the receiving device based on the energy state level, so as to encode the energy state level into the timing of the Bluetooth communication; and a response processing module for receiving the control message sent by the receiving device and responding to the screen projection strategy adjustment proposal based on its own situation; The receiving device is configured with: a round-trip time measurement module for measuring the round-trip response time of a Bluetooth data packet; a delay decoding module for decoding the energy state level of the sending device based on the delay difference between the round-trip response time and a preset benchmark round-trip time; a policy negotiation module for sending a control message containing a screen projection strategy adjustment proposal to the sending device when the decoded energy state level meets the preset conditions, the screen projection strategy adjustment proposal including at least one of reducing the video stream resolution, reducing the video stream frame rate, and changing the video stream encoding bit rate; and a collaborative execution module for collaboratively executing the screen projection strategy adjustment with the sending device after receiving a confirmation response from the sending device.

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