Thermal management of radio frequency filters in wireless networking devices

Abstract

Embodiments of the invention relate to thermal management of radio frequency filters in wireless networking devices. An example cooling system for a wireless networking device is presented. The cooling system includes a Peltier cooler disposed in thermal contact with a radio frequency (RF) filter coupled to a transceiver disposed in a wireless networked device. In addition, the cooling system includes a thermal management controller coupled to the Peltier cooler and the transceiver. The thermal management controller is configured to receive a signal indicating whether the transceiver is performing data communication. In response to determining that the transceiver is performing the data communication, the thermal management controller operates the Peltier cooler to actively cool the RF filter. However, in response to determining that the transceiver is not performing data communication while the wireless networked device is powered on, the thermal management controller operates the Peltier cooler to stop actively cooling the RF filter.

Description

Background Art

[0001] Wireless networking devices use frequency filters to transmit and receive signals within a specific frequency range. In particular, in wireless local area network (WLAN) technology, due to the use of multiple frequency bands such as 2.4GHz Wireless Fidelity (Wi-Fi band), 5GHz Wi-Fi band, and 6GHz Wi-Fi band, there is an increasing demand for radio frequency (RF) filtering, mainly to separate channels operating in adjacent frequency bands. In order to avoid inter-channel interference and increase channel bandwidth utilization, RF filters with sharp transition bands in the passband are necessary. Although these RF filters may not generate much heat during operation, the heat generated by adjacent electronic components (e.g., power amplifiers used in transceivers) may cause the RF filter to heat up, thereby affecting the performance of the RF filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] One or more examples of the present disclosure are described in detail with reference to the following drawings. The drawings provided are for illustration purposes only and depict examples only.

[0003] Figure 1 depicts a block diagram of a wireless networking device in which various examples presented herein may be implemented;

[0004] Figure 2 A flow chart depicting an example method for operating a cooling device in a wireless networking device;

[0005] Figure 3 A flow chart depicting another example method for operating a cooling device in a wireless networking device;

[0006] Figure 4 depicts a graphical representation showing an example temperature distribution of an RF filter corresponding to a voltage applied to a cooling device; and

[0007] Figure 5 A block diagram of an example computing system is depicted.

[0008] The drawings are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. DETAILED DESCRIPTION

[0009] Although the 6 GHz band has great potential in improving channel availability and throughput for Wi-Fi communications, Wi-Fi channel allocations in the 6 GHz band may create coexistence issues with existing 5 GHz Wi-Fi channels. For example, when a wireless networking device (e.g., an access point or router) simultaneously operates a 5 GHz radio using a 5 GHz U-NII channel allocation and a 6 GHz radio using the proposed U-NII 6 GHz channel allocation, jitter and interference may occur for certain Wi-Fi channels in the 5 GHz and 6 GHz bands. Specifically, when a wireless networking device receives a signal in a Wi-Fi channel at or near the upper limit of the 5 GHz frequency band while generating another signal in a Wi-Fi channel at or near the lower limit of the 6 GHz frequency band (or when a wireless networking device receives a signal in a Wi-Fi channel at or near the lower limit of the 6 GHz frequency band while generating another signal in a Wi-Fi channel at or near the upper limit of the 5 GHz frequency band), the received signal may experience jitter and interference from the generated signal, resulting in desensitization of the received signal (e.g., shorter coverage range) and degradation of signal quality (e.g., lower throughput).

[0010] With the upcoming IEEE Wi-Fi 7 802.11be standard, key features such as multi-link operation can provide some new opportunities for flexibly and dynamically utilizing access point radios to provide channels that can provide higher throughput and low latency. In some implementations, in order to provide such higher throughput and low latency, the access point radio has been redesigned to have available Wi-Fi bands. For example, in some known implementations, the access point is designed to operate multiple radios in a single band. For example, in five-band operation, one radio can be dedicated to the 2.4 GHz band, and two radios can be dedicated to the 5 GHz and 6 GHz bands, respectively. Such multi-band multi-radio operation may not only cause coexistence issues between the 5 GHz Wi-Fi channel and the 6 GHz Wi-Fi channel, but also may cause coexistence issues between Wi-Fi channels within each of the 5 GHz and 6 GHz bands.

[0011] As the frequency selectivity requirements for wireless networking devices operating simultaneously on multiple closely spaced frequency bands continue to increase, RF filter technology is being used to implement such applications. In particular, in order to separate communications on different channels, wireless networking devices typically implement RF filters. Typically, RF filters such as bulk acoustic wave (BAW) filters are well suited to meet such requirements with good performance at low cost.

[0012] BAW filters can be designed to selectively filter any frequency range from hundreds of MHz to 2.5GHz. With the inclusion of the 6GHz band in the Wi-Fi spectrum, BAW filter technology has gained commercial interest and can be extended to operate at frequencies from 5GHz to 7GHz, providing higher quality factors (Q factors), clarity (e.g., values ​​greater than 3000) compared to other traditional ceramic filters, and the ability to filter incredibly narrow frequency spans that separate the 5GHz Wi-Fi band from the 6GHz Wi-Fi band. Traditional ceramic filters are limited by their Q factors (e.g., achieving a Q factor of less than 1000) to provide the required level of rejection, resulting in a transition band greater than 200MHz. For BAW filters, such a transition band can be less than 80MHz wide.

[0013] BAW filtering technology also has some disadvantages, one of which is its temperature stability. BAW filters use microelectromechanical system (MEMS) oscillators based on silicon resonators, and their operation can be sensitive to temperature changes. In some cases, a certain size of temperature change may detune the fine-tuned resonator, thereby negatively affecting the electrical filtering characteristics of the BAW filter. Typically, BAW filters operate inside a product (e.g., an access point) that includes several electronic components that generate heat in addition to adjacent and ambient thermal changes. For example, in wireless networking devices such as access points, local temperature changes may vary significantly due to changes in ambient temperature and due to the operation of transceivers and processing units. For example, electronic components such as power amplifiers can have extremely variable temperature distributions, depending on the efficiency, rate, and duty cycle of their operation. Although BAW filters can generate minimal or no heat during operation, the heat generated by the power amplifier or other electronic components may be coupled into adjacent BAW filters by conduction via a shared printed circuit board or by convection (accumulated heat on the surrounding housing and air temperature within the wireless networking device). This thermal coupling can increase its temperature. Temperature increases in BAW filters beyond certain limits may negatively impact the filtering capabilities of the BAW filters, causing wireless networking devices to operate unreliably.

[0014] Some known techniques to address this problem may require designing the BAW filter with some additional margin in its specifications to maintain appropriate system-level requirements over the expected temperature operating range. This margin may be at the expense of relaxing the specifications, limiting the temperature or power operating range, or accepting limited filtering performance of the BAW filter, which in some cases may result in inconsistent operation at the system level.

[0015] In order to compensate for the adverse effects of temperature fluctuations on RF filtering performance, in an example consistent with the teachings of the present disclosure, a wireless networking device (e.g., an AP) is designed to implement active cooling of an RF filter and selective control of active cooling. In particular, the wireless networking device may include a wireless communication circuit including a transceiver and an RF filter (e.g., a BAW filter) coupled to the transceiver. In addition, the wireless networking device may include a cooling system coupled to the wireless communication circuit to cool the RF filter. The cooling system includes a cooling device (e.g., a Peltier cooler) arranged to be in thermal contact with the RF filter and a thermal management controller coupled to the cooling device and the transceiver. The cooling device can actively cool the RF filter. The term "active cooling" or "actively cooling" may refer to a heat exchange arrangement that uses power to cool a target device (e.g., an RF filter in this case). During operation, active cooling of the RF filter by the proposed cooling device can provide relative temperature stability for the RF filter. Therefore, the RF filter does not have to compromise on design specifications to establish margins for a wider operating temperature range and manufacturing yields, thereby allowing the wireless networking device to operate with increased peak performance over a wider operating range.

[0016] Typically, when a wireless networking device is performing data communications, electronic components (e.g., a power amplifier) ​​in the transceiver generate higher heat than when data communications are not being performed (e.g., when the transceiver is idle). Therefore, in an example consistent with the teachings of the present disclosure, the thermal management controller is configured to selectively operate a cooling device for a duration when data communications occur. To achieve this, the thermal management controller is configured to receive a signal indicating whether the transceiver is performing data communications. Based on the signal, the thermal management controller determines whether the transceiver is performing data communication activities. Therefore, if it is determined that active cooling of the RF filter is required during a period when the transceiver is performing data communication activities, the thermal management controller operates the cooling device. On the other hand, in response to determining that the wireless networking device is powered on, but the transceiver is not performing data communication activities, the thermal management controller can deactivate the cooling device.

[0017] It should be appreciated that such selective operation of the cooling device reduces the energy required to operate the cooling device. Additionally, any type of cooling device, such as a low-cost Peltier cooler, may generate additional heat due to its inherent efficiency to the overall system during operation. In such an implementation, the proposed selective control of the Peltier cooler can transfer heat coupled into the RF filter away from the RF filter while minimizing the total heat added to the system, thereby improving the performance of the RF filter.

[0018] The following detailed description refers to the accompanying drawings. It should be clearly understood that the drawings are for illustration and description purposes only. Although several examples are described in this document, modifications, adaptations and other implementations are also possible. Therefore, the following detailed description does not limit the disclosed examples. On the contrary, the proper scope of the disclosed examples can be defined by the attached claims. The system 100 in which the various examples presented herein can be implemented.

[0019] Now referring to the accompanying drawings, Figure 1 A block diagram of an example wireless networking device 100 is depicted in which various examples presented herein may be implemented. The wireless networking device 100 may be deployed in a wireless local area network (WLAN) to provide Wi-Fi connectivity to client devices. For example, the wireless networking device 100 may participate in any network data transmission operation, including, but not limited to, switching, routing, bridging, or a combination thereof. In some examples, for example, the wireless networking device 100 may provide wireless connectivity to client devices (not shown) using wireless communication technologies specified in one or more of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard specifications.

[0020] In one example implementation, the wireless networking device 100 may include a wireless access point, commonly referred to as an access point (AP). An AP may be an electronic device suitable for allowing a wireless device to connect to a wired network via various communication standards. An AP may include any hardware components useful for performing the invention disclosed herein, including but not limited to a processor, a memory, a display device, an input device, a communication device, etc. A person of ordinary skill in the art will appreciate that the wireless networking device 100 may be any (multiple) suitable type of wireless networking device that implements a wireless connection between two or more wireless-capable devices (e.g., client devices connected to an AP).

[0021] In addition to other circuits and electronic components (not shown), in some examples, the wireless networking device 100 may also include a wireless communication circuit 102 and a cooling system 104 for cooling one or more components of the wireless communication circuit 102. In particular, the wireless communication circuit 102 includes electronic devices for enabling data communication via the wireless networking device 100. The wireless communication circuit 102 may form a part of one or more radio circuits (not shown) implemented in the wireless networking device 100. The radio circuit may include electronic circuits for processing signals received and / or transmitted via the wireless networking device 100. Each of the radio circuits may operate one or more channels in one or more frequency bands (e.g., a 2.4 GHz Wi-Fi band, a 5 GHz Wi-Fi band, or a 6 GHz Wi-Fi band) that conform to one or more IEEE standards. In some other examples, the radio circuit may also include hardware suitable for operating in accordance with other wireless communication technologies (e.g., a cellular communication protocol). Those skilled in the art will appreciate that the wireless networking device 100 may include any appropriate number of radio circuits to operate one or more wireless communication channels. In some example implementations, the radio circuits may be dedicated to each of the 2.4 GHz Wi-Fi band, the 5 GHz Wi-Fi band, the 6 GHz Wi-Fi band, or any sub-band within any of the 2.4 GHz Wi-Fi band, the 5 GHz Wi-Fi band, and the 6 GHz Wi-Fi band. In an example implementation, one or more of the radio circuits may include wireless communication circuitry 102.

[0022] Wireless communication circuitry 102 may include transceiver 106, radio frequency (RF) filter 108, and temperature sensor 110. For example, transceiver 106 may include electronic circuitry for transmitting and / or receiving data according to any wireless communication technology, including but not limited to those described in one or more IEEE standards or cellular communication protocols. Some example electronic circuits implemented in wireless communication circuitry 102 may include power amplifiers, low noise amplifiers (LNAs), modulators, demodulators, phase shifters, signal comparators, signal conditioning circuits, etc. In some examples, wireless communication circuitry 102 may also include one or more antennas (not shown) connected to the electronic circuitry to enable transmission and reception of data.

[0023] The RF filter 108 is connected to the transceiver 106 to allow signals having a specific frequency or having a frequency within a specific frequency range to be transmitted and received via the transceiver 106. In some examples, the RF filter 108 can be designed to have a predetermined passband to allow specific signals to pass through the RF filter 108, thereby providing isolation between operating channels of the wireless networking device 100. In the examples described herein, the "passband" of a given RF filter refers to the range of frequencies that the given RF filter allows to pass (e.g., transmit or receive) when the given RF filter is applied to a given signal. Examples of the RF filter 108 may include a bulk acoustic wave (BAW) filter, a surface acoustic wave (SAW), a ceramic filter, a dielectric filter, a tuned microwave cavity, and the like. It will be understood that in the description below, although several examples are described with reference to the RF filter 108 as a BAW filter, other types of RF filters may also benefit from the proposed solution.

[0024] The ambient temperature around the wireless networking device 100 may fluctuate due to several external factors. In addition, one or more components of the transceiver 106 may generate heat during the operation of the wireless networking device 100. For example, in the wireless networking device 100, local temperature changes may vary significantly due to changes in ambient temperature and the operation of the transceiver 106. For example, electronic components such as power amplifiers in the transceiver 106 may have extremely variable temperature distributions, depending on the efficiency of their operation. Although the RF filter 108 may generate minimal or no heat during its operation, the heat generated by the power amplifier or other electronic components of the wireless networking device 100 may be coupled into the RF filter 108 by conduction through a shared printed circuit board (not shown) or by concentrated heat in the surrounding housing and the air temperature within the wireless networking device 100. If appropriate control measures are not implemented, this thermal coupling into the RF filter 108 may increase the temperature of the RF filter 108, thereby negatively affecting the filtering ability of the RF filter 108.

[0025] To compensate for the adverse effects of temperature fluctuations on the performance of the RF filter 108, in an example consistent with the teachings of the present disclosure, the wireless networking device 100 is designed to implement active cooling of the RF filter 108 and selective control of such active cooling. In particular, the wireless networking device 100 may include a cooling system 104 coupled to the wireless communication circuit 102 to cool the RF filter 108. The term "active cooling" or "actively cooling" may refer to a heat exchange arrangement that uses electrical power to cool a target device (e.g., in this case, the RF filter 108). For example, such active cooling may be performed by a Peltier effect cooler.

[0026] The cooling system 104 includes a cooling device 112 (eg, a Peltier cooler), a heat sink 114, and a thermal management controller 116. Figure 1 , the heat sink 114 is shown as having a specific shape including multiple heat sinks, but the heat sink 114 can be any device or structural element, such as an antenna board, a shield, a housing, etc., whose temperature is lower than the temperature of the RF filter 108 and has sufficient thermal mass to act as a sink or storage for thermal energy. The cooling device 112 is placed in thermal contact with both the RF filter 108 and the heat sink 114. The terms "thermal contact" or "thermal coupling" used herein may refer to a direct or indirect connection between two components so that heat can be conducted from one component to another component. The thermal management controller 116 is also coupled to the cooling device 112 and the transceiver 106 to control the operation of the cooling device 112 based on the data communication activity carried via the transceiver 106. During operation, active cooling of the RF filter 108 via the cooling device 112 can provide temperature stability for the RF filter 108. Therefore, the RF filter 108 may not have to compromise on design specifications to build margin for a wider operating temperature range, thereby allowing the wireless networking device 100 to operate at peak performance.

[0027] The cooling device 112 may be a heat transfer device that consumes power and thereby cools the RF filter 108. In an example implementation, the cooling device 112 may be implemented as a Peltier cooler. Other types of active cooling devices may also be implemented in the wireless networking device 100 without limiting the scope of the present disclosure. For purposes of illustration below, Figure 1 The invention is described as having a Peltier cooler implemented as cooling device 112. In such an implementation, cooling device 112 includes a cold side plate 113 and a hot side plate 115. Figure 1 In an example implementation of FIG. 1 , the cooling device 112 is sandwiched between the RF filter 108 and the heat sink 114, such that the cold side plate 113 is positioned in thermal contact with the RF filter 108, and the hot side plate 115 is positioned in thermal contact with the heat sink 114. During operation, when electrical energy (e.g., voltage) is applied to the cooling device 112, a temperature difference is generated between the cold side plate 113 and the hot side plate 115, such that the cold side plate 113 remains cooler than the hot side plate 115, thereby cooling the RF filter 108. The heat sink 114 absorbs heat from the hot side plate 115 and conducts the heat away from the RF filter 108 via its heat sink.

[0028] As will be appreciated, cooling devices such as Peltier coolers generate heat (e.g., by increasing the temperature of the hot side plate 115), which increases the chances of such heat being coupled into the RF filter 108. Thus, according to the examples presented herein, the thermal management controller 116 may be configured to control the operation of the cooling device 112 such that excess heat generated by the cooling device 112 (e.g., by the Peltier cooler heating its hot side plate 115) may be controlled, thereby resulting in a reduction in the amount of heat generated internally to the wireless networking device 100. This in turn will reduce any heat coupled into the RF filter 108.

[0029] The temperature sensor 110 may be disposed near the RF filter 108. In particular, the temperature sensor 110 measures the temperature near the RF sensor 110. In one example, the temperature measurement may be in the form of an electrical parameter measurement, such as a voltage or current proportional to the temperature. In another example, the temperature measurement may be in the form of a code corresponding to the magnitude of the temperature. In some examples, the thermal management controller 116 may monitor such temperature measurements to control the operation of the cooling device 112.

[0030] The thermal management controller 116 may include at least one processing resource (e.g., processing resource 118) and a machine-readable storage medium 120, the machine-readable storage medium including (e.g., encoded with) instructions 122, which are executable by the processing resource 118 to implement various functions of the thermal management controller 116. The machine-readable storage medium 120 may be non-transitory, and is alternatively referred to as a non-transitory machine-readable storage medium, not covering transient propagating signals. The machine-readable storage medium 120 may be any electronic, magnetic, optical, or any other type of storage device that can store data and / or executable instructions. Examples of the machine-readable storage medium 120 may include random access memory (RAM), non-volatile RAM (NVRAM), electrically erasable programmable read-only memory (EEPROM), storage drives (e.g., solid-state drives (SSD) or hard disk drives (HDD)), flash memory, optical storage, etc. The machine-readable storage medium 120 may be encoded with instructions 122 to control the operation of the cooling device 112. Although not shown, in some examples, the machine-readable storage medium 120 may be encoded with certain additional executable instructions to perform any other operations performed by the wireless networking device 100 or the thermal management controller 116 without limiting the scope of the present disclosure.

[0031] The processing resource 118 may be a physical device, such as a central processing unit (CPU), a microprocessor, a graphics processing unit (GPU), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), other hardware device capable of retrieving and executing instructions stored in the machine-readable storage medium 120, or a combination thereof. The processing resource 118 may retrieve, decode, and execute instructions 122 stored in the machine-readable storage medium 120 to control the operation of the cooling device 112. As an alternative or in addition to executing the instructions 122, the processing resource 118 may include at least one integrated circuit (IC), control logic, electronic circuitry, or a combination thereof, which includes several electronic components for performing the functions intended to be performed by the thermal management controller 116. According to some examples, the thermal management controller 116 may implement a method for controlling the operation of the cooling device 112 by executing the instructions 122 through the processing resource 118. In some examples, the processing resource 118 may execute one or more of the instructions 122 to perform a method in conjunction with Figure 2 and Figure 3 Describe the method steps.

[0032] In some examples, the thermal management controller 116, through the processing resource 118 executing the instructions 122, can selectively operate the cooling device 112 during the duration when the transceiver 106 is performing data communication. To achieve this, the thermal management controller 116 is configured to receive a signal indicating whether the transceiver 106 is performing data communication. Based on the signal, the thermal management controller 116 determines whether the transceiver 106 is performing data communication activities. Therefore, the thermal management controller 116 operates the cooling device 112 to actively cool the RF filter 108 during the period when the transceiver 106 is performing data communication activities. On the other hand, in response to determining that the wireless networking device 100 is powered on and the transceiver 106 is not performing data communication activities, the thermal management controller 116 can operate the cooling device 112 to stop actively cooling the RF filter 108.

[0033] As will be appreciated, such selective operation of the cooling device 112 reduces the energy required to operate the cooling device 112. Furthermore, the proposed selective control of the cooling device 112 may reduce the heat generated internally of the wireless networking device 100.

[0034] In the following description, with the help of Figure 2 and Figure 3The flowcharts shown in the flowcharts are used to describe several operations performed by a thermal management controller (e.g., thermal management controller 116). In some examples, the operations described in these flowcharts can be performed by a processing resource (e.g., processing resource 118) by executing instructions (e.g., instructions 122) stored in a machine-readable storage medium (e.g., machine-readable storage medium 120). As an alternative or in addition to retrieving and executing instructions, the operations described in these flowcharts can be performed by implementing one or more electronic circuits (such as FPGAs, ASICs, or other electronic circuits) including electronic components.

[0035] Reference now Figure 2 , depicts a method for controlling a cooling device (e.g., Figure 1 In particular, the method 200 represents an example technique for controlling active cooling of an RF filter (e.g., the RF filter 108) based on data communication activity conducted via a transceiver (e.g., the transceiver 106) such that heat coupled into the RF filter is minimized and performance of the RF filter is not affected.

[0036] In step 202, a thermal management controller (e.g., thermal management controller 116) receives a signal indicating whether the transceiver is performing data communication. Data communication may include wireless data transmission or wireless data reception. More specifically, in one example, data communication may include wireless data transmission or wireless data reception in accordance with one or more specifications of the IEEE 802.11 specification. In one example, the transceiver may generate a signal such as "power amplifier enabled" (PA enabled) or "low noise enabled" (LNA enabled) according to the data communication activity. In particular, the signal characteristics (e.g., logic state, voltage magnitude, current magnitude, or power magnitude) of the "PA enabled" signal may indicate whether the power amplifier of the transceiver is enabled and whether the transceiver is transmitting data. Similarly, the signal characteristics of the "LNA enabled" signal may indicate whether the transceiver is receiving data from an external device. The logic state may represent any one of a voltage magnitude, a current magnitude, or a power magnitude. For example, a voltage magnitude greater than or equal to 3 volts may be represented as a logic state "1", while a voltage magnitude less than 3 volts may be represented as a logic state "0". The example Table 1 below shows the logic states of the "PA Enable" and "LNA Enable" signals and the corresponding data communication states.

[0037] Signal Logical state Data communication status PA Enable 1 The transceiver is performing a data transfer. PA Enable 0 The transceiver is not performing a data transfer. LNA Enable 1 The transceiver is performing data reception. LNA Enable 0 The transceiver is not performing data reception.

[0038] Table 1: Example logical states representing data communication status

[0039] At step 204, the thermal management controller may perform a check to determine whether the transceiver is performing data communication. In one example, the transceiver may analyze signals, such as "PA enable" and "LNA enable", to determine whether the transceiver is performing data communication. For example, if any one of "PA enable" and "LNA enable" is identified as having a logic state of "1", the thermal management controller may determine that the transceiver is performing data communication. On the other hand, if any one of "PA enable" and "LNA enable" is identified as having a logic state of "0", the thermal management controller may determine that the transceiver is not performing data communication.

[0040] In step 204, if it is determined that the transceiver is performing data communication, then in step 206, the thermal management controller can operate a cooling device (e.g., a Peltier cooler) to actively cool the RF filter. In order to actively cool the RF filter, the thermal management controller can apply a control signal of a predefined size to the cooling device. For the purposes of the following description, the control signal is described as a voltage signal of a Peltier cooler implemented as a cooling device. As will be appreciated, in some other examples, depending on the type of cooling device, the control signal can be a current or power. For example, as long as a voltage signal of a predefined size is applied to the cooling device, the cooling device continues to reduce the temperature of the cold side plate and increase the temperature of the hot side plate. The cold side plate of the cooling device in thermal contact with the RF filter cools the RF filter. In addition, the hot side plate in thermal contact with the radiator transfers heat to the radiator.

[0041] However, at step 204, if it is determined that the transceiver is not performing data communications when the wireless networking device is powered on, then at step 208, the thermal management controller can operate the cooling device (e.g., disconnect the cooling device) to stop actively cooling the RF filter. In order to stop actively cooling the RF filter, the thermal management controller can stop applying the voltage signal to the cooling device. As a result, the temperature of the hot side plate can stop rising. As will be appreciated, since no data communications are occurring, the transceiver may not generate any heat. The above-described controlled operation of the cooling device can not only help cool the RF filter (e.g., during the duration that data communications are being performed), but can also minimize additional heat generation via the cooling device (e.g., during the duration that data communications are not being performed).

[0042] Reference now Figure 3 , a method for controlling a cooling device (e.g., Figure 11. A flow chart of another example method 300 of operation of an RF filter (e.g., RF filter 108) for controlling active cooling of an RF filter (e.g., RF filter 108) based on data communication activity and temperature measurements made via a temperature sensor (e.g., temperature sensor 110) is provided. For the sake of brevity, certain details of the operations described in any previous figures are not repeated herein. In particular, method 300 represents an example technique for controlling active cooling of an RF filter (e.g., RF filter 108) based on data communication activity and temperature measurements made via a temperature sensor (e.g., temperature sensor 110) such that heat coupled into the RF filter is minimized and performance of the RF filter is not affected.

[0043] At step 302, a thermal management controller (e.g., Figure 1 The thermal management controller 116) receives a signal indicating whether the transceiver is performing data communication. Figure 2 As described above, the signal may include a "PA enable" signal or an "LNA enable" signal indicating whether the transceiver is performing data transmission or data reception, respectively. In addition, at step 304, the thermal management controller may perform a check to determine whether the transceiver is performing data communication, for example, based on an analysis of the "PA enable" and "LNA enable" signals. Figure 2 304, if it is determined that the transceiver is not performing data communication when the wireless networking device is powered on, then in step 306, the thermal management controller may operate the cooling device to stop actively cooling the RF filter. To stop actively cooling the RF filter, the thermal management controller may stop applying a voltage signal to the cooling device, thereby stopping heat transfer to the RF filter through the cooling device. After execution of step 306, in step 302, the thermal management controller may continue to monitor the signal indicating whether the transceiver is performing data communication.

[0044] Now returning to step 304, if it is determined that the transceiver is performing data communication, then in step 308, the thermal management controller can obtain a temperature sensor (e.g., temperature sensor 110, see Figure 1 ) receives a temperature measurement. In one example, the temperature measurement can be in the form of an electrical parameter measurement, such as a voltage or current proportional to the temperature near the temperature sensor. In another example, the temperature measurement can be in the form of a code corresponding to the magnitude of the temperature near the temperature sensor. The thermal management controller can then determine the temperature near the RF filter based on a mapping or correlation between the electrical parameter measurement or code and the temperature value.

[0045] At step 310, the thermal management controller may perform another check to determine if the temperature measurement is within a predefined range. The predefined range may be a range of temperature values ​​that are acceptable for satisfactory performance of the RF filter. In one example, the predefined range may be customized by an administrator. At step 310, if it is determined that the temperature measurement is within the predefined range, then at step 306, the thermal management controller may operate the cooling device to stop actively cooling the RF filter. After execution of step 306, at step 302, the thermal management controller may continue to monitor the signal indicating whether the transceiver is performing data communications.

[0046] However, in step 310, if it is determined that the temperature measurement is outside the predefined range, then in step 312, the thermal management controller may operate a cooling device (e.g., a Peltier cooler) to actively cool the RF filter so that the temperature is maintained within the predefined range. In order to actively cool the RF filter, the thermal management controller may apply a voltage signal having a predefined size and a varying duty cycle to the cooling device. In particular, applying a voltage signal having a varying duty cycle may cause the cooling device to be temporarily activated and deactivated during a period in which the transceiver is performing data communication to maintain the temperature within the predefined range. In an example implementation, the thermal management controller may dynamically adjust the duty cycle of the voltage signal based on the temperature measurement. For example, the thermal management controller may increase the duty cycle of the voltage signal as the temperature increases, and reduce the duty cycle of the voltage signal as the temperature decreases, thereby maintaining the temperature within the predefined range. As long as the voltage signal of the predefined size is applied to the cooling device, the cooling device continues to maintain the temperature difference between its cold side plate and the hot side plate. The cooler cold side plate of the cooling device in thermal contact with the RF filter cools the RF filter. Additionally, the thermal side plate in thermal contact with the heat sink transfers heat to the heat sink. After executing step 312, at step 302, the thermal management controller may continue to monitor a signal indicating whether the transceiver is performing data communications.

[0047] Now go to Figure 4 , presents a graphical representation 400 depicting an RF filter (e.g., Figure 1 108) implemented in the wireless networking device 100 of FIG. 10B, the temperature distribution corresponding to the temperature distribution applied to the cooling device (e.g., in FIG. 10B ). Figure 1100). In the graphical representation 400, an X-axis 402 represents time, and Y-axes 404 and 406 represent voltage magnitude and temperature magnitude, respectively. In addition, an operation axis 408 specifies an operation (e.g., data transmission or data reception) performed via a transceiver of the wireless networking device within a given duration. In the graphical representation 400, a curve 410 depicted using a dashed line represents a temperature measurement near the RF filter when no active cooling of the RF filter is performed.

[0048] In addition, according to one or more examples presented herein, curve 412 depicted using a solid line represents a temperature measurement near the RF filter when controlled active cooling of the RF filter is implemented. In addition, curve 414 represents a voltage signal with a varying duty cycle applied to a cooling device (e.g., a Peltier cooler). A thermal management controller (e.g., in the case of a cooling system (e.g., cooling system 104) Figure 1 The thermal management controller 116 implemented in the wireless networking device 100 of the embodiment of the present invention controls the operation of the cooling device to maintain the temperature measurement 412 within the predefined range ΔT by controlling the voltage signal 414 applied to the cooling device. As can be observed from the graphical representation 400, when active cooling of the RF filter is not implemented, the temperature measurement near the RF filter (plotted as curve 410) may exceed the predefined range ΔT.

[0049] like Figure 4 As shown, during the time periods T1-T2, T3-T4, and T5-T6, the transceiver performs data communication (e.g., data transmission or reception). However, in the time periods T2-T3 and T4-T5, no data communication is performed. Figure 4 As shown, during time periods T1-T2, T3-T4, and T5-T6, the thermal management controller applies a voltage signal 414 having a predefined magnitude to the cooling device to actively cool the RF filter. In some examples, as shown, the duty cycle of the voltage signal 414 is also varied to increase or decrease the amount of cooling via the cooling device. Therefore, it is observed that the temperature measurement 412 is maintained within the predefined range ΔT.

[0050] Figure 5 A block diagram of an example computing system 500 is depicted in which various examples described herein may be implemented. In some examples, the computing system 500 may be configured to function as a wireless networking device such as a Figure 1 The computing system 500 may be configured to operate as a wireless networking device (such as a wireless networking device 100) and may perform various operations described in conjunction with one or more of the previous figures. Figure 1The computing system 500 may be implemented as a wireless networking device 100 and may perform various operations described in one or more of the previous figures. Examples of devices and / or systems that may be implemented as the computing system 500 may include desktop computers, laptop computers, servers, network servers, authentication servers, AAA servers, DNS servers, DHCP servers, IP servers, VPN servers, network policy servers, mainframes, tablet computers, e-readers, netbook computers, televisions and similar monitors (e.g., smart TVs), content receivers, set-top boxes, PDAs, mobile phones, smart phones, intelligent terminals, dumb terminals, virtual terminals, video game consoles, virtual assistants, IoT devices, etc.

[0051] The computing system 500 may include a bus 502 or other communication mechanism for communicating information, a hardware processor (also referred to as a processing resource 504), and a machine-readable storage medium 505 coupled to the bus 502 for processing information. In some examples, the processing resource 504 may include one or more CPUs, semiconductor-based microprocessors, and / or other hardware devices suitable for retrieving and executing instructions stored in the machine-readable storage medium 505. The processing resource 504 may retrieve, decode, and execute instructions to control the operation of a cooling device (e.g., a Peltier cooler). As an alternative or in addition to retrieving and executing instructions, the processing resource 504 may include one or more electronic circuits including electronic components for performing the functions of one or more instructions, such as an FPGA, an ASIC, or other electronic circuit. In an example implementation, the processing resource 504 and the machine-readable storage medium 505 may be used together as a thermal management controller, such as in conjunction with a processor. Figure 1 The thermal management controller 116 is described.

[0052] In some examples, the machine-readable storage medium 505 may include a main memory 506, such as a RAM, cache, and / or other dynamic storage device, coupled to the bus 502 for storing information and instructions to be executed by the processing resource 504. The main memory 506 may also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by the processing resource 504. When stored in a storage medium accessible to the processing resource 504, such instructions render the computing system 500 as a special-purpose machine customized to perform the operations specified in the instructions. The machine-readable storage medium 505 may also include a read-only memory (ROM) 508 or other static storage device, which is coupled to the bus 502 for storing static information and instructions for the processing resource 504. In addition, in the machine-readable storage medium 505, a storage device 510 (such as a magnetic disk, optical disk, or universal serial bus (USB) thumb drive (flash drive) or the like) may be provided and coupled to the bus 502 for storing information and instructions.

[0053] In some examples, computing system 500 can be coupled to display 512, such as a liquid crystal display (LCD) (or touch-sensitive screen), via bus 502 for displaying information to a computer user. In some examples, input device 514, including alphanumeric and other keys (physical or software generated and displayed on a touch-sensitive screen), can be coupled to bus 502 for communicating information and command selections to processing resources 504. Additionally, in some examples, another type of user input device, such as cursor control 516, can be connected to bus 502. Cursor control 516 can be a mouse, trackball, or cursor direction keys. Cursor control 516 can communicate direction information and command selections to processing resource 504 for controlling cursor movement on display 512. In some other examples, the same direction information and command selections as a cursor control can be implemented by receiving touches on a touch screen without a cursor.

[0054] In some examples, computing system 500 may include a user interface module for implementing a graphical user interface (GUI), which may be stored in a mass storage device as executable software code executed by (multiple) computing devices. For example, this module and other modules may include components, such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, program code segments, drivers, firmware, microcode, circuit systems, data, databases, data structures, tables, arrays, and variables.

[0055] The computing system 500 also includes a network interface 518 coupled to the bus 502. The network interface (in Figure 5 The network interface 518 (labeled as "NW interface" in the figure) provides a two-way data communication coupling to one or more network links connected to one or more local networks. For example, the network interface 518 can be an integrated services digital network (ISDN) card, a cable modem, a satellite modem, or a modem for providing a data communication connection to a corresponding type of telephone line. As another example, the network interface 518 can be a local area network (LAN) card or a wireless communication unit (e.g., a Wi-Fi chip / module). In some examples, the network interface 518 may include wireless communication circuitry 520 (in the figure). Figure 5 518 ), which is an example representation of wireless communication circuitry 102. In addition, network interface 518 may include cooling hardware 522 (in Figure 5 ) which may include cooling devices and heat sinks (not shown) which are Figure 1 1 and 12. An example representation of cooling device 112 and heat sink 114 described in FIG.

[0056] In some examples, machine-readable storage medium 505 (e.g., one or more of main memory 506, ROM 508, or storage device 510) stores instructions 507, which when executed by processing resource 504 may cause processing resource 504 to perform one or more of the methods / operations described above. Instructions 507 may be stored on any of main memory 506, ROM 508, or storage device 510. In some examples, instructions 507 may be distributed across one or more of main memory 506, ROM 508, or storage device 510. In some examples, instructions 507 may include instructions that when executed by processing resource 504 may cause processing resource 504 to perform Figure 2 and Figure 3 Instructions of one or more of the methods described in.

[0057] Unless otherwise expressly stated, the terms and phrases used in this document and their variations should be interpreted as open-ended, rather than restrictive. As an example of the foregoing, the term "including" should be understood as "including but not limited to" and other meanings. The term "example" is used to provide an illustrative example of the project under discussion, rather than its exhaustive or restrictive list. The term "a" or "an" should be understood as "at least one", "one or more" and other meanings. In some cases, the appearance of broadening words and phrases such as "one or more", "at least", "but not limited to" or other similar phrases should not be understood as intending or needing to use narrower situations in the absence of such broadening phrases. In addition, the term "and / or" used in this article refers to and covers any and all possible combinations of related listed items. It should also be understood that although the terms first, second, third, etc. can be used to describe various elements in this article, these elements should not be limited by these terms, because unless otherwise specified or the context indicates otherwise, these terms are only used to distinguish one element from another element.

Claims

1. A cooling system for a wireless networking device, comprising: a Peltier cooler disposed in thermal contact with a radio frequency (RF) filter coupled to a transceiver, wherein the RF filter and the transceiver are disposed in the wireless networking device; a thermal management controller coupled to the Peltier cooler and the transceiver, wherein the thermal management controller is configured to: receiving a signal indicating whether the transceiver is performing data communications; In response to the signal indicating that the transceiver is performing the data communication, operating the Peltier cooler to actively cool the RF filter; as well as In response to the signal indicating that the transceiver is not performing the data communication when the wireless networking device is powered on, the Peltier cooler is operated to cease actively cooling the RF filter. 2 . The cooling system of claim 1 , wherein the RF filter is a bulk acoustic wave (BAW) filter, a surface acoustic wave (SAW) filter, a ceramic filter, a dielectric filter, or a tuned microwave cavity. 3 . The cooling system of claim 1 , wherein the data communication comprises wireless data transmission, wireless data reception, or both the wireless data transmission and the wireless data reception.

4. The cooling system of claim 1, further comprising a heat sink disposed in thermal contact with the Peltier cooler.

5. The cooling system of claim 4, wherein the Peltier cooler comprises a cold side plate and a hot side plate, wherein the Peltier cooler is sandwiched between the RF filter and the heat sink such that the cold side plate is disposed in thermal contact with the RF filter and the hot side plate is disposed in thermal contact with the heat sink.

6. The cooling system of claim 1 , further comprising a temperature sensor disposed adjacent to the RF filter to measure a temperature near the RF filter, wherein the thermal management controller is configured to operate the Peltier cooler such that the temperature is maintained within a predefined range.

7. The cooling system of claim 1, wherein the wireless networking device is an access point.

8. A method comprising: receiving, by a thermal management controller, a signal from a transceiver disposed in a wireless networking device indicating whether the transceiver is performing data communications, wherein the wireless networking device further comprises a cooling device disposed in thermal contact with a radio frequency (RF) filter coupled to the transceiver; In response to the signal indicating that the transceiver is performing the data communication, operating, by the thermal management controller, the cooling device to actively cool the RF filter; as well as In response to the signal indicating that the transceiver is not performing the data communication when the wireless networking device is powered on, the cooling device is operated by the thermal management controller to cease actively cooling the RF filter.

9. The method of claim 8, wherein the RF filter comprises a bulk acoustic wave (BAW) filter.

10. The method of claim 8, wherein the wireless networking device further comprises a heat sink disposed in thermal contact with the RF filter to provide passive cooling to the RF filter.

11. The method of claim 10, wherein the cooling device comprises a Peltier cooler, the Peltier cooler comprising a cold side plate and a hot side plate, wherein the Peltier cooler is sandwiched between the RF filter and the heat sink such that the cold side plate is arranged in thermal contact with the RF filter and the hot side plate is arranged in thermal contact with the heat sink.

12. The method of claim 8, wherein the wireless networking device further comprises a temperature sensor disposed adjacent to the RF filter to measure a temperature near the RF filter.

13. The method of claim 12, further comprising operating the cooling device to actively cool the RF filter such that the temperature is maintained within a predefined range.

14. The method of claim 13, wherein operating the cooling device to actively cool the RF filter comprises temporarily activating and deactivating the cooling device to maintain the temperature within the predefined range during a period when the transceiver is performing the data communication. 15 . The method of claim 14 , wherein temporarily activating and deactivating the cooling device comprises applying a voltage signal having a varying duty cycle to the cooling device based on the temperature. 16 . The method of claim 15 , wherein applying the voltage signal comprises increasing a duty cycle of the voltage signal as the temperature increases and decreasing the duty cycle of the voltage signal as the temperature decreases, thereby maintaining the temperature within the predefined range.

17. A wireless networking device, comprising: A wireless communication circuit comprising a transceiver and a bulk acoustic wave (BAW) filter coupled to the transceiver; as well as a cooling system coupled to the wireless communication circuit to cool the BAW filter, wherein the cooling system comprises: a Peltier cooler disposed in thermal contact with the BAW filter; and a thermal management controller coupled to the Peltier cooler and the transceiver, wherein the thermal management controller is configured to: receiving a signal indicating whether the transceiver is performing data communications; In response to the signal indicating that the transceiver is performing the data communication, operating the Peltier cooler to actively cool the BAW filter; and In response to the signal indicating that the transceiver is not performing the data communication when the wireless networking device is powered on, operating the Peltier cooler to cease actively cooling the BAW filter.

18. The wireless networking device of claim 17, wherein the data communications comprise wireless data communications performed in accordance with one or more of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specifications.

19. The wireless networking device of claim 17, wherein the cooling system further comprises a heat sink disposed in thermal contact with the Peltier cooler.

20. The wireless networking device of claim 17, wherein the cooling system further comprises a temperature sensor disposed adjacent to the BAW filter to measure a temperature near the BAW filter, wherein the thermal management controller is configured to control a duty cycle of a voltage signal applied to the Peltier cooler such that the temperature is maintained within a predefined range.

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