An active RIS thermal noise suppression and array element scheduling system and method

Abstract

This invention provides an active RIS thermal noise suppression and array element scheduling system and method. The system includes an active RIS panel, a temperature monitoring unit, and a RIS intelligent controller. The active RIS panel contains several active RIS array elements arranged in an array. The temperature monitoring unit is used to collect the operating temperature of the RIS array elements. The RIS intelligent controller establishes a thermal noise evaluation quantity based on the operating temperature of the RIS array elements, and calculates the net performance gain or marginal contribution of each active RIS array element by combining the channel state information, received power, or received signal-to-noise ratio fed back from the receiver. When the array element temperature exceeds the upper limit threshold of the safe temperature, the corresponding array element is switched to a passive reflection state or a dormant state, and is allowed to return to the active amplification state after the temperature drops to the cooling recovery threshold. Under the premise of meeting the minimum communication guarantee threshold, redundant array elements with low marginal contribution are pruned.

Description

Technical Field

[0001] This invention relates to the field of wireless communication and reconfigurable smart surface control technology, specifically to an active RIS thermal noise suppression and array element scheduling system and method. Background Technology

[0002] Traditional passive reconfigurable intelligent surfaces (RIS) consist of numerous low-cost passive reflective elements that redirect signals by adjusting the phase of incident electromagnetic waves. However, existing passive RIS technologies suffer from significant double-path loss, resulting in extremely limited end-to-end signal gain for long-distance near-field or far-field transmissions. Active RIS, on the other hand, integrates active amplification devices (such as reflective amplifiers) within the reflective elements. This not only allows for signal phase adjustment but also direct amplification of the incident signal, thereby providing significantly greater communication gain than passive RIS in non-line-of-sight (NLoS) scenarios.

[0003] However, although active RIS effectively improves system capacity and coverage, the introduction of active amplifier devices has revealed the following serious shortcomings in actual engineering deployment and long-term operation of existing systems:

[0004] 1. Hardware power consumption and severe heat accumulation: Active RIS array elements consume DC power when amplifying signals, and the energy conversion efficiency of RF devices is limited. A large amount of electrical energy that is not converted into RF energy will be converted into heat energy. In the form of dense array (massive MIMO), the active RIS panel will cause a sharp rise in local temperature and severe heat accumulation when it operates for a long time.

[0005] 2. Rising thermal noise leads to deterioration of system signal-to-noise ratio: As the operating temperature of the active RIS increases, the thermal noise generated by its internal active devices will be amplified and reflected to the receiver, causing strong active noise interference to the user's received signal.

[0006] 3. Inefficient array element management leads to resource waste: Current far-field or near-field beam training and scheduling schemes typically default to enabling all active array elements to maximize array gain. However, not all array elements make a significant positive contribution to the target user's line-of-sight or non-line-of-sight paths. Blindly enabling array elements in poor channel conditions or at the edge not only fails to effectively improve the receiver signal strength but also increases system power consumption and further exacerbates the heat generation and thermal noise problems of the entire panel, resulting in a double waste of resources. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the purpose of this invention is to provide an active RIS thermal noise suppression and array element scheduling system and method, which can significantly suppress the deterioration of active thermal noise, break through the system performance bottleneck under high temperature environment, and accurately eliminate invalid array elements, thereby achieving the ultimate balance between communication gain and energy consumption cost.

[0008] The technical solution of the present invention is as follows:

[0009] An active RIS thermal noise suppression and array element scheduling system includes an active RIS panel, a temperature monitoring unit, and a RIS intelligent controller. The active RIS panel includes several active RIS array elements arranged in an array. The temperature monitoring unit is used to acquire the operating temperature of individual or partial active RIS array elements. The RIS intelligent controller is connected to both the temperature monitoring unit and the active RIS panel. The RIS intelligent controller establishes a thermal noise evaluation quantity based on the operating temperature of the active RIS array elements and, in conjunction with channel state information, received power, or received signal-to-noise ratio fed back from the receiver, calculates the net performance gain or marginal contribution of each active RIS array element. When the array element temperature exceeds the upper limit threshold of the safe temperature, the corresponding array element is switched to a passive reflection state or a dormant state, and is allowed to return to the active amplification state after the temperature drops to the cooling recovery threshold. Under the premise of meeting the minimum communication guarantee threshold, redundant array elements with low marginal contribution are pruned.

[0010] Preferably, each active RIS array element integrates a reflective patch, a phase shifter, an active RF amplifier, and an RF switch.

[0011] Preferably, the temperature monitoring unit includes a MEMS temperature sensor array, with a MEMS temperature sensor integrated on the back of the substrate of each active RIS array element, for real-time acquisition of the physical operating temperature of each active RIS array element, and can capture the minute temperature rise generated by the active RIS array element during signal amplification in real time.

[0012] Preferably, the active RIS panel is divided into multiple sub-arrays, each sub-array being a block. A MEMS temperature sensor is integrated into each block to collect the average temperature of the block. If the average temperature of the block exceeds the block temperature threshold, the entire active RIS array element in the block will go into hibernation or be polled to go into hibernation.

[0013] Preferably, the RIS intelligent controller includes a temperature acquisition module, a baseband communication interface, and an array element status scheduling module. The controller internally runs a dynamic scheduling algorithm to periodically acquire the temperature of the RIS array elements. RIS intelligent controller according to Calculate the equivalent input thermal noise power of the i-th array element within the system bandwidth B, and according to... Calculate the equivalent noise cost of the i-th array element after amplification, where, Boltzmann's constant, Let be the noise coefficient of the i-th array element.

[0014] Preferably, if the temperature of an active RIS array element is detected to exceed the set safe temperature limit threshold, the RIS smart controller immediately puts the active RIS array element into hibernation. The array element stops working and enters a natural cooling state, thereby eliminating the extreme thermal noise interference introduced at that point. When the temperature of the hibernated array element drops to the set cooling recovery threshold through heat dissipation, the RIS smart controller unlocks it and re-marks it as standby.

[0015] Preferably, after shutting down some overheated array elements, the contribution of the array elements is evaluated. The RIS intelligent controller obtains the feedback signal-to-noise ratio from the user receiver, calculates the marginal performance contribution of all array elements in standby state, sets the minimum communication guarantee level required by the system, sorts all currently active array elements in ascending order of marginal performance contribution value, and attempts to set the array element with the smallest contribution at the end of the list to sleep state in turn. For each array element that goes into sleep state, it is monitored whether the overall received strength still meets the minimum communication guarantee level. If putting an array element into sleep state would cause the signal strength to fall below the minimum communication guarantee level, the sleep state action is stopped and the current state is maintained.

[0016] Furthermore, the present invention also provides an active RIS thermal noise suppression and array element scheduling method, comprising the following steps:

[0017] The RIS intelligent controller obtains the current temperature of each active RIS array element through a temperature monitoring unit;

[0018] Thermal noise and net performance gain of active RIS array elements were evaluated.

[0019] Implement a threshold-based forced shutdown and natural cooling strategy for overheated active RIS array elements.

[0020] Implement a shutdown strategy for redundant active RIS array elements to ensure signal strength.

[0021] The RIS intelligent controller iterates according to a preset time period to determine the final set of active RIS array elements to be activated.

[0022] Preferably, the step of implementing a threshold-based forced shutdown and natural cooling strategy for overheated active RIS array elements specifically includes:

[0023] Preset physical safety temperature upper limit threshold and cooling recovery threshold;

[0024] Overheat monitoring: Traverse the temperature set of active RIS array elements. If the temperature of an active RIS array element exceeds the set safety threshold, the RIS intelligent controller will forcibly shut down the active RIS array element.

[0025] Natural cooling: The active RIS array elements that have been turned off enter the natural cooling stage, and their temperature gradually decreases over time;

[0026] State wake-up: When the temperature monitoring unit detects that the temperature of the shut-down array element has dropped to the cooling recovery threshold, the array element is remarked as available and can participate in subsequent system gain scheduling.

[0027] Preferably, the step of implementing the shutdown strategy for redundant active RIS array elements to ensure signal strength specifically includes: after removing overheated array elements, the RIS intelligent controller performs a secondary screening on the remaining set of active RIS array elements that are not overheated and are in a usable state, sets the minimum received signal strength threshold required by the system, calculates the marginal contribution of each remaining array element to the target user's received signal, sorts the array elements according to the marginal contribution from low to high, and, under the premise that the user's received signal strength is continuously higher than the minimum received signal strength threshold, sequentially sets the state of the array element with the lowest contribution to be off. After each array element is turned off, it is monitored whether the overall received strength is still higher than the minimum received signal strength threshold. If turning off an array element would cause the signal strength to fall below the minimum received signal strength threshold, the shutdown action is stopped and the current state is maintained.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. Significantly suppresses active thermal noise degradation, breaking through system performance bottlenecks in high-temperature environments: Existing systems blindly activate the entire array in pursuit of high signal gain, leading to a continuous rise in the temperature of active devices. The amplified thermal noise severely interferes with the signal-to-noise ratio at the receiver. This invention, by introducing a MEMS temperature sensor array, achieves microscopic sensing of the physical state at the RIS array element level for the first time. When the temperature of an array element is detected to be higher than the upper limit of the safe temperature threshold, the system immediately forces the active amplifier of that element to shut down, directly cutting off the source of extreme thermal noise. This allows overheated array elements to shut down for heat dissipation in time and resume operation after the temperature returns to the safe threshold.

[0030] 2. Precisely eliminate invalid array elements to achieve the ultimate balance between communication gain and energy consumption cost: Under the premise of ensuring that the signal strength received by the user end is greater than the required threshold, this invention actively shuts down those redundant array elements that do not make a substantial contribution to the net gain of the system by evaluating the marginal contribution of each available array element to the target signal, thereby achieving a fine balance between gain protection and power saving. Attached Figure Description

[0031] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0032] Figure 1 This is a block diagram of the active RIS thermal noise suppression and array element scheduling system of the present invention;

[0033] Figure 2 A schematic diagram of an active RIS array structure for integrating a MEMS temperature sensor.

[0034] Figure 3 This is a flowchart of the active RIS thermal noise suppression and array element scheduling method of the present invention.

[0035] Figure 4 A schematic diagram of the forced shutdown and natural cooling strategy for overheated active RIS array elements;

[0036] Figure 5 This is a schematic diagram of the shutdown strategy for redundant active RIS array elements. Detailed Implementation

[0037] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0038] Specifically, this invention provides an active RIS thermal noise suppression and array element scheduling system, which is deployed in a non-line-of-sight (NLoS) communication environment where there are obstacles obstructing the transmission and reception ends, such as... Figure 1 As shown, the system includes an active RIS panel, a temperature monitoring unit, and a RIS intelligent controller. The output of the temperature monitoring unit is connected to the temperature acquisition module of the RIS intelligent controller via an internal data bus; the control signal output of the RIS intelligent controller is connected to each active RIS array element.

[0039] like Figure 2 As shown, the active RIS panel comprises N active RIS array elements arranged in an array. Each active RIS array element integrates a phase shifter, an active RF amplifier, and an RF switch. Unlike passive RIS, the active reflective array elements in this embodiment can directly amplify the power of the incident signal, with the amplification gain preferably ranging from 10dB to 30dB.

[0040] The temperature monitoring unit is used to acquire the physical operating temperature of a single or partial active RIS array element in real time and feed the temperature data back to the RIS intelligent controller. The temperature monitoring unit includes a MEMS temperature sensor array. A MEMS temperature sensor is integrated on the back of the substrate of each active RIS array element. The sensor is used to acquire the physical operating temperature of each active RIS array element in real time. The MEMS temperature sensor has the characteristics of fast response speed and small size, and can capture the small temperature rise generated by the active RIS array element in real time during signal amplification.

[0041] In an alternative embodiment, instead of equipping each individual array element with a temperature sensor one-to-one, the active RIS panel is divided into multiple sub-arrays, for example... Each array element is considered a block. A temperature sensor is attached to the center or backplane of each block to collect the average temperature of that block. If the average temperature of a block exceeds the limit, the entire block will go into sleep mode or the array elements within that block will be put into sleep mode by polling.

[0042] The RIS intelligent controller includes a temperature acquisition module, a baseband communication interface, and an array element state scheduling module. The RIS intelligent controller is connected to the RF switches and MEMS sensors of all array elements via a control bus. Internally, the controller runs a dynamic scheduling algorithm to periodically acquire the temperature of the RIS array elements. RIS intelligent controller according to Calculate the equivalent input thermal noise power of the i-th array element within the system bandwidth B, and according to... Calculate the equivalent noise cost of the i-th array element after amplification, where, Boltzmann's constant, Let be the noise coefficient of the i-th array element.

[0043] The RIS intelligent controller reads the temperature of the active RIS array elements in real time via MEMS sensors. If detected , To reach the upper limit of the safe temperature range, the controller immediately shuts down (puts the active RIS array element into hibernation). At this point, the element stops operating and enters a natural cooling state, thereby eliminating extreme thermal noise interference introduced at this point. When the temperature of the hibernated element drops to a safe level through heat dissipation... hour, To cool down and restore the threshold, the RIS smart controller unlocks and re-marks it as "standby".

[0044] In an optional embodiment, when an array element is detected to be overheating, instead of completely cutting off all power to that element, only the active RF amplifier inside the element is shut down, while its phase shifter continues to operate. In this case, the overheated active array element is physically degraded to a passive reflective array element. This eliminates the high heat and thermal noise from the active amplifier while retaining the element's ability to adjust the signal phase, resulting in less signal attenuation than if it were completely shut down.

[0045] Furthermore, after overheating of some array elements in the dormant state, an algorithm is used to ensure that communication performance does not drastically degrade and to save on electricity costs. First, the contribution of array elements is evaluated, and the controller obtains the feedback signal-to-noise ratio (SNR) from the user receiver. The marginal performance contribution of all array elements in the "standby" state is calculated; and the minimum communication guarantee level required by the system is set. Sort all currently active array elements in ascending order of their marginal performance contribution. Attempt to put the last array element with the smallest contribution into sleep mode. After each element goes into sleep mode, monitor whether the overall received signal strength still meets the minimum communication guarantee level. If putting an array element into hibernation causes the signal strength to fall below a threshold, the hibernation action will stop, and the current state will be maintained.

[0046] Furthermore, the present invention also provides an active RIS thermal noise suppression and array element scheduling method, such as... Figure 3 As shown, the method includes the following steps:

[0047] S1: The RIS intelligent controller obtains the current temperature of each active RIS array element through the temperature monitoring unit;

[0048] Specifically, after the system starts up, the RIS intelligent controller acquires temperature data through the MEMS temperature sensor array. The set of current absolute temperatures of each active RIS array element .

[0049] S2: Perform thermal noise and net performance gain assessments of active RIS array elements.

[0050] Specifically, when an active RIS array is operational, the active RIS array elements in the ON state inject amplified thermal noise into the system. According to the physical thermodynamic model, the... The inherent thermal noise power generated by each active RIS array element is ,in Boltzmann's constant, For system bandwidth, The noise figure. The total signal-to-noise ratio (SNR) of the user at the system receiver can be modeled as:

[0051]

[0052] in, This is the dynamic response matrix of RIS. To transmit beams for base stations, Based on the current temperature The determined thermal noise diagonal matrix This is the receiver's noise floor.

[0053] For each active RIS array element The RIS intelligent controller is evaluated for its net performance gain, which depends not only on the strength of the cascaded channel it provides but also on its current temperature. The resulting thermal noise penalty.

[0054] S3: Implement a threshold-based forced shutdown and natural cooling strategy for overheated active RIS array elements.

[0055] Specifically, such as Figure 4 As shown, the preset physical safety temperature upper limit threshold and cooling recovery threshold .

[0056] Overheat monitoring: Traversing the temperature set If the temperature of an active RIS array element exceeds the set safe temperature limit threshold, i.e. When this happens, the controller forces the switch state of the array element to be turned off to eliminate the large amount of thermal noise it generates and to prevent hardware damage.

[0057] Natural cooling: The array elements that are turned off enter the natural cooling phase, and their temperature gradually decreases over time.

[0058] State wake-up: When the temperature monitoring unit detects that the temperature of the shut-down array element has dropped to the cooling recovery threshold, i.e. At this time, the array element is remarked as "available" and can participate in subsequent system gain scheduling.

[0059] S4: Implement a shutdown strategy for redundant active RIS array elements to ensure signal strength.

[0060] Specifically, such as Figure 5 As shown, after removing overheated array elements, in order to further save system power consumption costs and reduce overall heat generation, the RIS intelligent controller performs a secondary screening of the remaining unheated array element set that is in a usable state.

[0061] Set the minimum received signal strength threshold required by the system. .

[0062] Calculate the marginal contribution of each remaining array element to the target user's received signal. Array elements with low marginal contribution are usually in the severe fading region of the NLoS path, and their amplification effect is negligible, but they will still consume the full DC power consumption and generate thermal noise.

[0063] The pairs are sorted from low to high according to their marginal contribution.

[0064] Continuously meet the user's received signal strength Under the premise of [the above conditions], the array elements with the lowest contribution are turned off in sequence. Those array elements that do not substantially improve system performance are actively put into sleep mode, thereby significantly saving the overall power consumption of the system and slowing down the rate of temperature rise of the RIS panel from the source.

[0065] Each time an array element is turned off, the system monitors whether the overall received signal strength still meets the minimum received signal strength threshold. If turning off an array element would cause the signal strength to fall below the minimum received signal strength threshold, the turning-off action is stopped and the current state is maintained.

[0066] S5: The RIS intelligent controller iterates according to a preset time period to determine the final set of active RIS array elements to be activated.

[0067] As communication progresses, environmental channel changes, and the temperature of active array elements dynamically evolves, the RIS intelligent controller responds at preset time intervals. The process involves continuous iteration, repeatedly executing the aforementioned closed loop of state acquisition, thermal assessment, and dynamic scheduling.

[0068] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. An active RIS thermal noise suppression and array element scheduling system, characterized in that, The system includes an active RIS panel, a temperature monitoring unit, and a RIS intelligent controller. The active RIS panel comprises several active RIS elements arranged in an array. The temperature monitoring unit is used to acquire the operating temperature of individual or partial active RIS elements. The RIS intelligent controller is connected to both the temperature monitoring unit and the active RIS panel. The RIS intelligent controller establishes a thermal noise assessment quantity based on the operating temperature of the active RIS elements and, in conjunction with channel state information, received power, or received signal-to-noise ratio fed back from the receiver, calculates the net performance gain or marginal contribution of each active RIS element. When the element temperature exceeds the upper limit threshold of the safe temperature, the corresponding element is switched to a passive reflection state or a dormant state, and is allowed to return to the active amplification state after the temperature drops to the cooling recovery threshold. Under the premise of meeting the minimum communication guarantee threshold, redundant elements with low marginal contribution are pruned.

2. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, Each active RIS array element integrates a reflective patch, a phase shifter, an active RF amplifier, and an RF switch.

3. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, The temperature monitoring unit includes a MEMS temperature sensor array. A MEMS temperature sensor is integrated on the back of the substrate of each active RIS array element to collect the physical operating temperature of each active RIS array element in real time. It can capture the small temperature rise generated by the active RIS array element during signal amplification in real time.

4. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, The active RIS panel is divided into multiple sub-arrays, each sub-array being a block. A MEMS temperature sensor is integrated into each block to collect the average temperature of the block. If the average temperature of the block exceeds the block temperature threshold, the entire active RIS array element in the block will either go into hibernation or be polled to go into hibernation.

5. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, The RIS intelligent controller includes a temperature acquisition module, a baseband communication interface, and an array element status scheduling module. The controller internally runs a dynamic scheduling algorithm to periodically acquire the temperature of the RIS array elements. RIS intelligent controller according to Calculate the equivalent input thermal noise power of the i-th array element within the system bandwidth B, and according to... Calculate the equivalent noise cost of the i-th array element after amplification, where, Boltzmann's constant, Let be the noise coefficient of the i-th array element.

6. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, If the temperature of an active RIS array element exceeds the set safe temperature limit threshold, the RIS smart controller immediately puts the active RIS array element into hibernation. The array element stops working and enters a natural cooling state, thereby eliminating the extreme thermal noise interference introduced at that point. When the temperature of the hibernated array element drops to the set cooling recovery threshold through heat dissipation, the RIS smart controller unlocks it and re-marks it as standby.

7. The active RIS thermal noise suppression and array element scheduling system according to claim 1, characterized in that, After shutting down some overheated array elements, the contribution of the array elements is evaluated. The RIS intelligent controller obtains the feedback signal-to-noise ratio from the user receiver, calculates the marginal performance contribution of all array elements in standby mode, sets the minimum communication guarantee level required by the system, sorts all currently active array elements in ascending order of marginal performance contribution value, and attempts to set the array element with the smallest contribution at the end of the list to sleep mode. For each array element that goes into sleep mode, it monitors whether the overall received signal strength still meets the minimum communication guarantee level. If putting an array element into sleep mode would cause the signal strength to fall below the minimum communication guarantee level, the sleep mode action is stopped and the current state is maintained.

8. A method for suppressing thermal noise and scheduling array elements in an active RIS system, characterized in that, The method includes the following steps: The RIS intelligent controller obtains the current temperature of each active RIS array element through a temperature monitoring unit; Thermal noise and net performance gain of active RIS array elements were evaluated. Implement a threshold-based forced shutdown and natural cooling strategy for overheated active RIS array elements. Implement a shutdown strategy for redundant active RIS array elements to ensure signal strength. The RIS intelligent controller iterates according to a preset time period to determine the final set of active RIS array elements to be activated.

9. The active RIS thermal noise suppression and array element scheduling method according to claim 8, characterized in that, The steps of implementing the threshold-based forced shutdown and natural cooling strategy for overheated active RIS array elements specifically include: Preset physical safety temperature upper limit threshold and cooling recovery threshold; Overheat monitoring: Traverse the temperature set of active RIS array elements. If the temperature of an active RIS array element exceeds the set safety threshold, the RIS intelligent controller will forcibly shut down the active RIS array element. Natural cooling: The active RIS array elements that have been turned off enter the natural cooling stage, and their temperature gradually decreases over time; State wake-up: When the temperature monitoring unit detects that the temperature of the shut-down array element has dropped to the cooling recovery threshold, the array element is remarked as available and can participate in subsequent system gain scheduling.

10. The active RIS thermal noise suppression and array element scheduling method according to claim 8, characterized in that, The steps of implementing the shutdown strategy for redundant active RIS array elements to ensure signal strength specifically include: after removing overheated array elements, the RIS intelligent controller performs a secondary screening on the remaining set of active RIS array elements that are not overheated and are in a usable state, sets the minimum received signal strength threshold required by the system, calculates the marginal contribution of each remaining array element to the target user's received signal, sorts the array elements from low to high according to the marginal contribution, and, under the premise that the user's received signal strength is continuously higher than the minimum received signal strength threshold, sequentially sets the state of the array element with the lowest contribution to be off. After each array element is turned off, it is monitored whether the overall received strength is still higher than the minimum received signal strength threshold. If turning off an array element would cause the signal strength to fall below the minimum received signal strength threshold, the shutdown action is stopped and the current state is maintained.

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