WO2020125979A1

WO2020125979A1 - Hardware component lifetime

Info

Publication number: WO2020125979A1
Application number: PCT/EP2018/085984
Authority: WO
Inventors: Magnus Sandgren; Martin Isberg; Agneta LJUNGBRO
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2018-12-19
Filing date: 2018-12-19
Publication date: 2020-06-25

Abstract

A method for controlling a lifetime of at least one component of a base station is disclosed. The component has a component temperature, and the base station is configured to use – at each time instant – one of a plurality of operational modes. Each operational mode is associated with a respective power consumption. The method comprises – when a predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during a time interval exceeds a second threshold value – preventing (during the time interval) the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value. Corresponding apparatus, network node, base station and computer program product are also disclosed.

Description

HARDWARE COMPONENT LIFETIME

TECHNICAL FIELD

The present disclosure relates generally to the field of base stations for wireless communication. More particularly, it relates to controlling the lifetime of one or more components of such base stations.

BACKGROUND

Base stations are generally subject to thermal conditions. Such thermal conditions may, for example, be related to self-heating (typically caused by power dissipation in components within the base station) and/or to environmental conditions at the location of the base station (e.g., ambient temperature and/or other physical circumstances).

A typical example of environmental conditions is meteorological conditions at the geographical location of the base station (e.g., temperature, sun exposure, wind velocity, etc.). The ambient temperature can vary significantly for different geographical locations, different times during the day, different parts of the year, etc.

Thermal conditions are typically challenging to a base station. Unfavorable thermal conditions may cause lifetime degradations and/or permanent damage. This becomes even more prominent in relation to the current trend towards physically smaller products (e.g., without active cooling systems).

Therefore, there is a need for new approaches to handle thermal conditions of a base station. Preferably, such approaches provide control of the lifetime of a base station (e.g., by controlling the lifetime of components of the base station). Controlling the lifetime may, for example, include increasing or preserving the lifetime.

SUMMARY

It should be emphasized that the term "comprises/comprising" (replaceable by "includes/including") when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Generally, when an arrangement is referred to herein, it is to be understood as a physical product; e.g., an apparatus. The physical product may comprise one or more parts, such as controlling circuitry in the form of one or more controllers, one or more processors, or the like.

It is an object of some embodiments to solve or mitigate, alleviate, or eliminate at least some of the above or other disadvantages.

A first aspect is a method for controlling a lifetime of at least one component of a base station, wherein the component has a component temperature. The base station is configured to use - at each time instant - one of a plurality of operational modes, wherein each operational mode is associated with a respective power consumption.

The method comprises - when a predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during a time interval exceeds a second threshold value - preventing, during the time interval, the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value.

In some embodiments, the method further comprises enforcing traffic load reduction for the base station when the predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during the time interval exceeds the second threshold value.

In some embodiments, the time interval is an upcoming time interval.

Then, the method may, according to some embodiments, further comprise predicting a behavior of the component temperature for the upcoming time interval and - when the predicted behavior indicates a predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during the upcoming time interval that exceeds the second threshold value - preventing, during the upcoming time interval, the base station from operating in any operational mode having associated power consumption that is lower than the third threshold value.

In some embodiments, the method further comprises biasing the component temperature based on a weather forecast for the upcoming time interval, applicable to a geographical location of the base station. For example, predicting a behavior of the component temperature may comprise biasing the component temperature based on a weather forecast for the upcoming time interval.

In some embodiments, the method further comprises monitoring the component temperature, and predicting a behavior of the component temperature based on the monitored component temperature.

In some embodiments, the method further comprises monitoring one or more of traffic load, used operational modes, and weather applicable to geographical location of the base station. Then, the method may also comprise providing a monitored behavior of the component temperature as a function of one or more of: the monitored traffic load, the monitored used operational modes, and the monitored weather applicable to geographical location of the base station. Furthermore, the method may comprise predicting the behavior of the component temperature based on the monitored behavior of the component temperature.

In some embodiments, predicting the behavior of the component temperature comprises predicting that the behavior of the component temperature during the upcoming time interval will correspond to a behavior of the monitored component temperature during one or more previous time intervals.

In some embodiments, the method further comprises estimating the lifetime of the component based on the monitored behavior of the component temperature, and preventing the base station from operating in any operational mode having associated power consumption that is lower than the third threshold value only when the estimated lifetime is shorter than a fourth threshold value.

In some embodiments, estimating the lifetime of the component is further based on a predicted traffic growth. In some embodiments, the method further comprises - when the estimated lifetime is shorter than the fourth threshold value - one or more of: enforcing traffic load reduction for the base station, and enforcing a transmission power reduction for the base station.

A second aspect is a computer program product comprising a non-transitory computer readable medium, having thereon a computer program comprising program instructions. The computer program is loadable into a data processing unit and configured to cause execution of the method according to the first aspect when the computer program is run by the data processing unit.

A third aspect is an apparatus for controlling a lifetime of at least one component of a base station, wherein the component has a component temperature. The base station is configured to use - at each time instant - one of a plurality of operational modes, wherein each operational mode is associated with a respective power consumption.

The apparatus comprises controlling circuitry configured to cause - when a predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during a time interval exceeds a second threshold value - prevention, during the time interval, of the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value.

A fourth aspect is a network node comprising the apparatus of the third aspect.

In some embodiments, the network node of the fourth aspect is the base station.

In some embodiments, any of the above aspects may additionally have features identical with or corresponding to any of the various features as explained above for any of the other aspects.

An advantage of some embodiments is that new approaches to handle thermal conditions of a base station are provided.

Another advantage of some embodiments is that control of the lifetime of a base station is enabled, for example, by enabling control of the lifetime of components of the base station. BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages will appear from the following detailed description of embodiments, with reference being made to the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments.

Figure 1 is a state diagram illustrating example operational modes according to some embodiments;

Figure 2 is a collection of plots illustrating example behavior of component temperature according to some embodiments;

Figure 3 is a flowchart illustrating example method steps according to some embodiments;

Figure 4 is a schematic plot illustrating example dynamic ranges of component temperature according to some embodiments;

Figure 5 is a schematic plot illustrating example lifetime estimations according to some embodiments;

Figure 6 is a schematic histogram illustrating example distribution magnitudes of component temperature changes according to some embodiments;

Figure 7 is a schematic drawing illustrating an example arrangement for monitoring of component temperature according to some embodiments;

Figure 8 is a schematic block diagram illustrating an example apparatus according to some embodiments; and

Figure 9 is a schematic drawing illustrating an example computer readable medium according to some embodiments.

DETAILED DESCRIPTION

As already mentioned above, it should be emphasized that the term "comprises/comprising" (replaceable by "includes/including") when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Embodiments of the present disclosure will be described and exemplified more fully hereinafter with reference to the accompanying drawings. The solutions disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the embodiments set forth herein.

In the following, embodiments will be described where the lifetime of one or more components of a base station is controlled by application of new approaches to handle thermal conditions. Controlling the lifetime may, for example, result in preserved and/or increased lifetime. The lifetime of the base station may, for example, be defined as the shortest lifetime among its components.

Typically, a base station is configured to use an operational mode at each moment in time (time instant). The operational mode may be one of a plurality of operational modes that the base station is configured to use.

Furthermore, a base station is typically configured to switch between different operational modes in response to some switching condition being fulfilled. Switching conditions may comprise any suitable condition and may, for example, relate to momentary traffic load.

At each moment in time, different hardware parts and/or functional blocks of the base station may operate according to different, respective, operational modes. Then, the operational mode of the base station may be defined as a combination of the respective operational modes used.

Application of a plurality of operational modes and switching between different operational states is well known and is commonly used, for example, to control power consumption of a base station. In such approaches, each operational mode is typically associated with a respective power consumption, wherein at least two of the respective power consumptions are different. For example, all of the respective power consumptions may be different. The power consumption associated with an operational mode may, for example, be defined as a maximum allowable power consumption of the operational mode, and/or as an average power consumption of the operational mode.

In some approaches, the transition time required for switching from one operational mode to another operational mode may depend on which operational modes are involved in the switch (e.g., on the difference between the respective power consumptions of the operational modes involved in the switch). For example, a longer duration of time may be required for switching from an operational mode with a very low associated respective power consumption to an operational mode with a very high associated respective power consumption, than is required for switching between operational modes with equal or similar associated respective power consumptions.

Typically, self-heating is dependent on power consumption. For example, a relatively high power consumption may result in a relatively high self-heating. Therefore, controlling the power consumption may be one way to control the thermal conditions of components of a base station.

Figure 1 is a state diagram illustrating example operational modes according to some embodiments. In this example, the plurality of operational modes comprises an ON-mode 101, a Sleepl-mode 102, a Sleep2-mode 103, a Sleep3-mode 104, and an OFF-mode 105. The ON- mode 101 has an associated power consumption P_0N, the Sleepl-mode 102 has an associated power consumption Psi_eepi/ the Sleep2-mode 103 has an associated power consumption Ps i_eep2 the Sleep3-mode 104 has an associated power consumption P_sleep3, and the OFF- mode 105 has an associated power consumption P_{0 FF}, where P_0N > P_sleepl > Psi_eep2 > P_sleep3 > POFF· The transition time required for switching to the ON-mode 101 from the other operational modes are denoted T 1 for Sleepl-mode 102, T 2 for Sleep2-mode 103, T 3 for Sleep3-mode 104, and G4 for OFF-mode 105, where G4 > T3 > T2 > T 1. Thus, the power consumption may be kept lower at expense of a higher latency for transition to the ON-mode.

According to some radio access technologies, there may be transmissions (e.g., for control purposes) even if no traffic is served. Such conditions counteract efficient use of low power operational modes and may result in that the power consumption does not scale with the amount of served traffic. For example, the power consumption may be high (entailing prominent self-heating) even when there is no served traffic at all.

According to some radio access technologies (e.g., Third Generation Partnership Project New Radio - 3GPP NR), the power consumption is more directly scalable with served traffic. These possibilities may be beneficial to reduce the self-heating (e.g., to decrease average temperature and/or accumulated time above a high-temperature threshold value. Thereby, lifetime of one or more components of the base station may be controlled (e.g. preserved and/or increased) since accumulated time above a high-temperature threshold value typically affects the lifetime of components of the base station.

However, approaches where the power consumption is more directly scalable with served traffic may lead to frequent changes between operational mode(s) associated with relatively high power consumption and operational mode(s) associated with relatively low power consumption. This behavior typically entails corresponding frequent changes between relatively high temperatures and relatively low temperatures, which can also negatively affect the lifetime of components of the base station.

Frequent temperature changes of high magnitude may be particularly harmful to the lifetime of components of the base station. The magnitude of a temperature change may be defined as the absolute value of the difference between the temperature before the change and the temperature after the change.

Figure 2 is a collection of plots illustrating example behavior of component temperature. Part (a) of Figure 2 illustrates a component temperature as a function of time. For example, the component temperature may vary in correspondence with one or more of a traffic load, a used operational mode, and a power consumption. During a time interval 200, the component temperature undergoes a number of frequent temperature changes of relatively high magnitude 210.

One approach to control the lifetime of a base station is to decrease the magnitude 210 in periods of frequent temperature changes. One way of achieving this is to prevent operation in low power operational mode(s), which would typically avoid low temperature 201. Example results of such an approach is illustrated in part (b) of Figure 2. Here, use of one or more operational mode(s) associated with low power consumption is prevented during the time interval 200, which leads to that the lowest temperature 202 in this interval is higher than the corresponding lowest temperature 201 in the situation illustrated in part (a). Thereby, the magnitude 211 of the frequent temperature changes is decreased compared to the situation illustrated in part (a).

Part (c) of Figure 2 illustrates that the component temperature may, additionally, vary in correspondence with the ambient temperature 220. For example, the ambient temperature may be high at some time during the day (illustrated at 221) and low at some time during the day (illustrated at 222). If high magnitude changes are only (or particularly) harmful at high average temperature, it may be particularly beneficial to prevent operation in low power operational mode(s) when the average temperature is high (e.g. when the ambient temperature is expected to be high, at some particular time during the day, etc.). Similarly, prevention of operation in low power operational mode(s) might not be beneficial when the average temperature is low, even if frequent temperature changes of relatively high magnitude occurs.

Figure 3 illustrates an example method 300 for controlling a lifetime of at least one component of a base station. The component may, for example be a component that is critical to the function of the base station and/or a component that is prone to early dysfunction. Example components of which it may be beneficial to control the lifetime includes power amplifiers and solder joints.

The base station is configured to use - at each time instant - one of a plurality of operational modes (e.g., the operational modes 101, 102, 103, 104, 105 of Figure 1), wherein each operational mode is associated with a respective power consumption.

The method comprises preventing, in step 360, the base station from operating in low power modes(s) when there are frequent high-magnitude component temperature changes (Y-path out of step 350). Typically, the prevention is applied during a time interval.

Put differently, the method comprises - when a predicted number of component temperature changes (each having a magnitude which exceeds a first threshold value) during a time interval exceeds a second threshold value - preventing (during the time interval) the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value.

For example, the time interval may be an upcoming time interval. Then, the method may comprise predicting a behavior of the component temperature for the upcoming time interval as illustrated by optional step 340. When the predicted behavior indicates a predicted number of component temperature changes of respective magnitudes (wherein each magnitude exceeds the first threshold value) during the upcoming time interval that exceeds the second threshold value, the base station may be prevented (during the upcoming time interval) from operating in any operational mode having associated power consumption that is lower than the third threshold value.

Generally, predictions (or general determinations) regarding component temperature may be based on one or more of measured (and/or statistically collected) component temperature, measured (and/or statistically collected) traffic load, and measured (and/or statistically collected) use of operational modes. In one example, the traffic load may be monitored, and it may be determined that there are frequent high-magnitude component temperature changes based on observed frequent high-magnitude fluctuations in traffic load (with or without monitoring of the component temperature). In one example, the use of operational modes may be monitored, and it may be determined that there are frequent high-magnitude component temperature changes based on observed frequent switching between low power mode(s) and high power mode(s) (with or without monitoring of the component temperature).

Optional step 370 illustrates that the method may also comprise enforcing traffic load reduction for the base station under the same conditions as the prevention of the base station from operating in low power modes(s). Traffic load reduction may be achieved in different ways. One way to reduce traffic load is to handover traffic (e.g., to another cell/sector, to another radio access technology, to, another frequency band, etc.). Another way to reduce traffic load is to enforce quality reduction for traffic services.

Steps 360 and 370 may be collectively seen as lifetime controlling actions 380. The method may further comprise one or more of several other, optional, steps as will be exemplified in the following.

Step 310 illustrates that the method may comprise monitoring the component temperature. The temperature of each of the one or more components may be monitored separately. Alternatively, some or all of the one or more components may be subject to joint temperature monitoring. Typically, the component temperature is monitored by a temperature sensor placed in, on, at, or in a vicinity of the component whose temperature is to be monitored.

Optional step 310 may further comprise also monitoring one or more of: traffic load, used operational modes, and weather applicable to geographical location of the base station. The monitored temperature (as well as the monitored traffic load, operational modes, weather, etc.) may be used to provide component temperature statistics indicative of a component temperature behavior (e.g., as a function of time of the day/week/year, traffic load, and/or weather conditions). For example, such statistics may be indicative of under which conditions frequent high-magnitude component temperature changes may be expected.

Such a statistics indication may, for example, be utilized to predict the behavior of the component temperature in step 340.

For example, predicting the behavior of the component temperature may comprise predicting that the behavior of the component temperature during the upcoming time interval will correspond to a behavior of the monitored component temperature during one or more previous time intervals. The previous time interval(s) may, for example, be a same time interval during a previous day/week/year.

Alternatively or additionally, predicting the behavior of the component temperature comprises biasing the component temperature based on a weather forecast for the upcoming time interval, applicable to a geographical location of the base station.

An example might be that the component temperature statistics indicate that there are typically frequent component temperature changes on weekdays around noon during the month of May, and the weather forecast is used such that the prevention of step 360 is applied on relatively warm days; but not on relatively cold days. Another example might be that the component temperature statistics indicate that there are typically frequent component temperature changes on Saturday evenings, and the weather forecast is used such that the prevention of step 360 is not applied when rain/snow/wind is expected.

Alternatively, the behavior of the component temperature may be predicted in step 340 based directly (and only) on the current behavior of the monitored component temperature of step 310 (i.e., without any component temperature statistics).

In a typical approach, predicting the behavior of the component temperature may comprise predicting that the behavior of the component temperature during the upcoming time interval will correspond to a behavior of the monitored component temperature during one or more previous time intervals, wherein the previous time interval is directly preceding the upcoming time interval.

For example, if frequent high-magnitude component temperature changes are currently experienced, the method may comprise preventing low power operational modes until the frequency of component temperature changes decreases. As illustrated by step 320, the method may comprise estimating the lifetime of the component (and indirectly of the base station) based on the monitored behavior of the component temperature from step 310. The lifetime estimation may, for example, be based on a predicted traffic growth (e.g., biasing the lifetime estimation based on a predicted traffic growth). Then, the prevention in step 360 of the base station from operating in any low power operational modes (operational mode having associated power consumption that is lower than the third threshold value) may be applied only when the estimated lifetime is shorter than a fourth threshold value as illustrated by the Y-path out of step 330.

In some embodiments, traffic load reduction is enforced (step 370) for the base station directly responsive to the estimated lifetime being shorter than the fourth threshold value (i.e., regardless of whether or not there are frequent component temperature changes.

Other lifetime controlling actions that may be undertaken, e.g., in step 380, when the estimated lifetime is shorter than the fourth threshold value includes enforcing a transmission power reduction for the base station. This may be achieved by application of step 360 as explained above, and may be supplemented by a general transmission power reduction for the base station (e.g., decreasing an average allowed power consumption and/or decreasing a maximum allowed power consumption.

The estimation of the component lifetime may be performed repeatedly as illustrated by the loop-backs to step 320, and when the estimated lifetime is no longer shorter than the fourth threshold value, one or more of the enforcements of step 380 may be lifted.

The first, second, third, and fourth thresholds may be static or dynamic. For example, one or more of them may depend on one or more of: an estimated lifetime, an ambient temperature, a predicted ambient temperature (e.g. based on statistics and/or weather forecast), a time of the day/week/year, etc.

The steps of the example method 300 may be combined in many different ways. A first example includes steps 340, 350 (loop-back to 340 for N-path), and 360 (loop-back to 340 at the end of the time interval); and possibly step 310 as a background activity on which the prediction of step 340 is based. A second example includes steps 310 (as a background activity to produce statistics), 320 (performed, e.g., at regular time intervals), 330 (loop-back to 320 for N-path), 340, 350 (loop-back to 340 for N-path), and 360. Numerous other possibilities exist.

Figure 4 schematically illustrates application of step 360 Figure 3. In this example, a first dynamic range 410 is applicable (e.g., during default operation), which means that component temperature changes may have a magnitude as large as the first dynamic range 410. For example, the upper limit of the dynamic range may be defined by an operational mode associated with a highest power consumption among the plurality of operational modes (compare with the ON-mode 101 of Figure 1) and the lower limit of the dynamic range may be defined by an operational mode associated with a lowest power consumption among the plurality of operational modes (compare with the OFF-mode 105 of Figure 1).

When there are frequent high-magnitude component temperature changes, a second (reduced) dynamic range 420 is enforced. Enforcement of the second dynamic range may be achieved by preventing use of one or more of the operational mode(s) associated with low power consumption (compare with step 360 of Figure 3), which leads to an increased lower limit of the dynamic range as illustrated by 402. Alternatively or additionally, enforcement of the second dynamic range may be achieved by a general transmission power reduction and/or by a traffic reduction (compare with step 370 of Figure 3), which leads to a decreased upper limit of the dynamic range as illustrated by 401. Figure 5 schematically illustrate two example lifetime estimations 532, 533 in a plot showing component wear as a function of time. Up to a current point in time 531, the component wear 541 due to thermal conditions may be determined, e.g., based on a monitored component temperature (compare with step 310 of Figure 3). Then, future wear 510, 520 may be estimated based on statistics of component temperature, traffic load, ambient temperature, weather data, estimated traffic growth, etc. The lifetime of the component may be estimated (compare with step 320 of Figure 3) as the point in time 532, 533 when the future wear reaches a failure level 542. As explained above, prevention of the base station from operating in any low power operational modes (compare with step 360 of Figure 3) may be applied only when the estimated lifetime is shorter (lower) than a fourth threshold value 534. Estimation of the lifetime of a component and/or of the base station may be performed in accordance with any suitable approach. One example will be given in the following.

By doing solder joint reliability simulations and early cycle testing the number of cycles to failure can be estimated for solder joints. Thermal simulations can give the temperature behavior over time for an estimated traffic profile and a specified environment (e.g. regarding ambient temperature). This knowledge can together give a provisional estimate of the lifetime by application of some failure distribution. Temperature dependent traffic could also be measured based on providing various traffic load and patterns as input to the base station in a measurement set-up.

Such a provisionally estimated lifetime can be used as a starting point for the estimation of the lifetime. By monitoring the temperature of the component (e.g., up to the time 531), sorting data for example into different temperature bins (see example of Figure 6) and using this information as new input data, the lifetime estimation 532, 533 may be updated iteratively.

Actual weather conditions during observation period (e.g., up to the time 531) and their statistical relation to the collected component temperature data can be used to tune the lifetime estimation model further. For example, if there has been an ambient temperature during the observation period that is higher than a statistically normal ambient temperature, the estimated lifetime might be biased (prolonged) based on the ambient temperature.

Furthermore, future changes (typically growth) in traffic load can be used to tune the lifetime estimation model further. For example, if traffic growth (and thereby higher component temperatures) is expected the estimated lifetime might be biased (shortened) based on the expected traffic growth. The relation between traffic growth and component temperatures can be derived from simulation data in relation to observed data. Traffic growth may also be related to a predicted change in traffic patterns (e.g., due to new services). Higher traffic load typically gives higher temperatures, which in turn may result in higher dynamics (magnitude of temperature changes) and higher frequency of occurrence of temperature changes.

Figure 6 is a schematic histogram illustrating example distribution magnitudes of component temperature changes. Determining such a quantized distribution may be helpful to determine when a number of component temperature changes of respective magnitudes (wherein each magnitude exceeds a first threshold value) during a time interval exceeds a second threshold value (compare with step 350 of Figure 3).

For example, all temperature changes having a magnitude exceeding the second threshold value may be sorted into the pile 603.

In some embodiments, there may be more than one second threshold value, each corresponding to prevention of different collections of low power operational modes. For example, when there are two second threshold values (a relatively low second threshold value and a relatively high second threshold value) all temperature changes having a magnitude not exceeding the relatively low second threshold value but may be sorted into the pile 601, all temperature changes having a magnitude exceeding the relatively low second threshold value but not the relatively high second threshold value may be sorted into the pile 602, and all temperature changes having a magnitude exceeding the relatively high second threshold value may be sorted into the pile 603.

The heights of the one or more of the piles (actual height or normalized using the accumulated heights of piles 601, 602, 603) may be used to decide whether or not to prevent low power operational mode(s). For example, the high of the pile 603 may be used to decide whether or not to prevent low power operational mode(s).

In the example of Figure 6, the accumulated heights of the piles 602 and 603 may be used to decide whether or not to prevent the lowest power operational mode (e.g., the OFF-mode 105 of Figure 1), and the height of the pile 603 may be used to decide whether or not to prevent the lowest power operational mode and one or more other operational modes (e.g., the Sleep3-mode 104 of Figure 1).

As shown in Figure 6, each pile of the histogram may also be indicative of two different regions (for the pile 603, the regions are denoted 610 and 620), wherein the lower number region may correspond to an acceptable number of temperature changes having a magnitude in the corresponding magnitude span, and the higher number region may correspond to an unacceptable number of temperature changes having a magnitude in the corresponding magnitude span. In such an approach, prevention of operational modes may be applied only for the higher number region, or prevention of operational modes may be applied more aggressively (preventing more operational modes) for the higher number region than for the lower number region.

Typically, it is not practical (or even possible) to monitor temperatures of all components in a base station. Therefore, components that are critical with respect to maximum temperature and/or temperature variations may be identified for monitoring (compare with step 310 of Figure 3). This may be accomplished, for example, using component specifications with requirements for thermal profiles and/or thermal simulation. A critical component may be defined as a component that is sensitive to high temperature and/or temperature variations, and is placed in a location within the base station where such temperature behaviour is likely to occur. In base stations, power amplifiers and solder balls in the transmitter stages may typically falls into this category.

The temperature data should preferably be accurate in terms that it monitors critical components of the base station and captures its dynamics. Thus, temperature sensors should preferably be placed at suitable locations; typically in the thermal vicinity of the critical component to be monitored. For accurate observation it may be beneficial if the temperature sensor has the same thermal time constant as the component to be monitored, such that - at each monitoring time instant - the sensor monitors the temperature of the critical component accurately. The monitoring time instant may also be important, so that monitoring takes place when the temperature of the component to be monitored is relevant for the controlling approach.

Figure 7 schematically illustrates an example arrangement for monitoring of component temperature. In this example, a power amplifier 700 is the component whose temperature is to be monitored, and a temperature sensor 710 is placed close thereto and outputs temperature data 711 to measurement and control data circuitry 720.

The measurement and control data circuitry 720 may be configured to monitor the component temperature (compare with step 310 of Figure 3), and uses clock and time keeping signals 702 and a utilization signal 701 to organize the temperature data.

A timing generator 730 controls the temperature sensor 710 by a timing strobe 703, based on input from the measurement and control data circuitry 720.

For example, the arrangement may be configured such that the temperature is measured often when the utilization is high (e.g., at high traffic load), when the ambient temperature is high, when the estimated lifetime is low, etc.

The temperature data 711 is also compared to a reference value 705 in comparator circuitry 740, and if the temperature data 711 exceeds the reference value 705, the comparator 740 outputs a control signal 704 to force the power amplifier to be turned off. Typically, the reference value 705 represents a maximum allowable temperature (e.g., above which the power amplifier 700 will probably be permanently damaged).

Figure 8 schematically illustrates an example apparatus for controlling a lifetime of at least one component of a base station. As above, the base station is configured to use (at each time instant) one of a plurality of operational modes, each operational mode being associated with a respective power consumption. The apparatus may, for example, be configured to execute, or cause execution of, any of the steps as explained above in connection with Figure 3.

The apparatus may, for example, be comprised in the base station 810. The base station typically comprises a transceiver (TX/RX; e.g., transceiving circuitry) 840 configured to accommodate traffic to and from one or more users. The base station may also comprise a power controller (PC, e.g., power control circuitry) 820 configured to control the power consumption, e.g., by switching between different operational modes and/or by limiting a general power consumption as described above.

Alternatively, the apparatus may be comprised in another network node operatively connected to, or otherwise associated with, the base station. Yet alternatively, the apparatus may be comprised in a cloud server with capability to control the base station.

The apparatus comprises controlling circuitry (CNTR; e.g., a processor or controller) 800, which is configured to cause prevention of the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value, during a time interval when a predicted number of component temperature changes (each having a magnitude which exceeds a first threshold value) exceeds a second threshold value (compare with step 360 of Figure 3). The prevention may, for example, comprise providing a control signal indicative of the prevented operational modes to the power controller.

When the time interval is an upcoming time interval, the controlling circuitry may be further configured to cause prediction of a behavior of the component temperature for the upcoming time interval (compare with step 340 of Figure 3). To this end the controlling circuitry may comprise, or be otherwise associated with (e.g., operably connected, or connectable, to) a predictor (PRED; e.g., prediction circuitry) 801 configured to predict the behavior of the component temperature for the upcoming time interval. The controlling circuitry may be further configured to cause monitoring of the component temperature (compare with step 310 of Figure 3) for prediction of the behavior of the component temperature based on the monitored component temperature. To this end the controlling circuitry may comprise, or be otherwise associated with (e.g., operably connected, or connectable, to) a monitor (MON; e.g., monitoring circuitry) 802 configured to monitor the component temperature. The monitor may also be configured to monitor one or more of traffic load, used operational modes, and weather applicable to geographical location of the base station and to provide a monitored behavior of the component temperature as a function of one or more of: the monitored traffic load, the monitored used operational modes, and the monitored weather applicable to geographical location of the base station. The controlling circuitry may be further configured to cause estimation of the lifetime of the component based on the monitored behavior of the component temperature (compare with step 320 of Figure 3) and prevention of the base station from operating in any operational mode having associated power consumption that is lower than the third threshold value only when the estimated lifetime is shorter than a fourth threshold value. To this end the controlling circuitry may comprise, or be otherwise associated with (e.g., operably connected, or connectable, to) an estimator (EST; e.g., estimating circuitry) 803 configured to estimate the lifetime of the component.

The described embodiments and their equivalents may be realized in software or hardware or a combination thereof. The embodiments may be performed by general purpose circuitry. Examples of general purpose circuitry include digital signal processors (DSP), central processing units (CPU), co-processor units, field programmable gate arrays (FPGA) and other programmable hardware. Alternatively or additionally, the embodiments may be performed by specialized circuitry, such as application specific integrated circuits (ASIC). The general purpose circuitry and/or the specialized circuitry may, for example, be associated with or comprised in an apparatus such as a network node (e.g., a base station or a network server node).

Embodiments may appear within an electronic apparatus (such as a network node) comprising arrangements, circuitry, and/or logic according to any of the embodiments described herein. Alternatively or additionally, an electronic apparatus (such as a network node) may be configured to perform methods according to any of the embodiments described herein.

According to some embodiments, a computer program product comprises a computer readable medium such as, for example a universal serial bus (USB) memory, a plug-in card, an embedded drive or a read only memory (ROM). Figure 9 illustrates an example computer readable medium in the form of a compact disc (CD) ROM 900. The computer readable medium has stored thereon a computer program comprising program instructions. The computer program is loadable into a data processor (PROC; e.g., data processing circuitry or a data processing unit) 920, which may, for example, be comprised in a network node 910. When loaded into the data processor, the computer program may be stored in a memory (MEM) 930 associated with or comprised in the data-processing unit. According to some embodiments, the computer program may, when loaded into and run by the data processing unit, cause execution of method steps according to, for example, any of the methods illustrated in Figure 3 or otherwise described herein.

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used.

Reference has been made herein to various embodiments. However, a person skilled in the art would recognize numerous variations to the described embodiments that would still fall within the scope of the claims.

For example, the method embodiments described herein discloses example methods through steps being performed in a certain order. However, it is recognized that these sequences of events may take place in another order without departing from the scope of the claims. Furthermore, some method steps may be performed in parallel even though they have been described as being performed in sequence. Thus, the steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step.

In the same manner, it should be noted that in the description of embodiments, the partition of functional blocks into particular units is by no means intended as limiting. Contra rily, these partitions are merely examples. Functional blocks described herein as one unit may be split into two or more units. Furthermore, functional blocks described herein as being implemented as two or more units may be merged into fewer (e.g. a single) unit.

Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever suitable. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Hence, it should be understood that the details of the described embodiments are merely examples brought forward for illustrative purposes, and that all variations that fall within the scope of the claims are intended to be embraced therein.

Claims

1. A method for controlling a lifetime of at least one component of a base station, the component having a component temperature, wherein the base station is configured to use - at each time instant - one of a plurality of operational modes (101, 102, 103, 104, 105), each operational mode being associated with a respective power consumption, the method comprising: when (350) a predicted number of component temperature changes, each having a magnitude (410) which exceeds a first threshold value, during a time interval (200) exceeds a second threshold value: preventing (360, 402), during the time interval, the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value.

2. The method of claim 1, further comprising enforcing (370, 401) traffic load reduction for the base station when the predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during the time interval exceeds the second threshold value.

3. The method of any of claims 1 through 2, wherein the time interval is an upcoming time interval.

4. The method of claim 3, further comprising biasing the component temperature based on a weather forecast for the upcoming time interval, applicable to a geographical location of the base station.

5. The method of any of claims 3 through 4, further comprising: monitoring (310) the component temperature; and predicting (340) a behavior of the component temperature based on the monitored component temperature.

6. The method of claim 5, further comprising: monitoring one or more of traffic load, used operational modes, and weather applicable to geographical location of the base station; providing a monitored behavior of the component temperature as a function of one or more of: the monitored traffic load, the monitored used operational modes, and the monitored weather applicable to geographical location of the base station; and predicting (340) the behavior of the component temperature based on the monitored behavior of the component temperature.

7. The method of any of claims 5 through 6, wherein predicting the behavior of the component temperature comprises predicting that the behavior of the component temperature during the upcoming time interval (200) will correspond to a behavior of the monitored component temperature during one or more previous time intervals.

8. The method of any of claims 5 through 7, further comprising: estimating (320) the lifetime of the component based on the monitored behavior of the component temperature; and preventing (360) the base station from operating in any operational mode having associated power consumption that is lower than the third threshold value only when (330) the estimated lifetime is shorter than a fourth threshold value.

9. The method of claim 8, wherein estimating the lifetime of the component is further based on a predicted traffic growth.

10. The method of any of claims 8 through 9, further comprising, when (330) the estimated lifetime is shorter than the fourth threshold value, one or more of: enforcing (370) traffic load reduction for the base station; and enforcing a transmission power reduction for the base station.

11. A computer program product comprising a non-transitory computer readable medium

(900), having thereon a computer program comprising program instructions, the computer program being loadable into a data processing unit and configured to cause execution of the method according to any of claims 1 through 10 when the computer program is run by the data processing unit.

12. An apparatus for controlling a lifetime of at least one component of a base station, the component having a component temperature, wherein the base station is configured to use - at each time instant - one of a plurality of operational modes, each operational mode being associated with a respective power consumption, the apparatus comprising controlling circuitry (800) configured to cause: when a predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during a time interval exceeds a second threshold value: prevention, during the time interval, of the base station from operating in any operational mode having associated power consumption that is lower than a third threshold value.

13. The apparatus of claim 12, wherein the controlling circuitry is further configured to cause enforcement of a traffic load reduction for the base station when the predicted number of component temperature changes, each having a magnitude which exceeds a first threshold value, during the time interval exceeds the second threshold value.

14. The apparatus of any of claims 12 through 13, wherein the time interval is an upcoming time interval.

15. The apparatus of claim 14, further comprising biasing of the component temperature based on a weather forecast for the upcoming time interval, applicable to a geographical location of the base station.

16. The apparatus of any of claims 14 through 15, wherein the controlling circuitry is further configured to cause: monitoring of the component temperature; and prediction of a behavior of the component temperature based on the monitored component temperature.

17. The apparatus of claim 16, wherein the controlling circuitry is further configured to cause: monitoring of one or more of traffic load, used operational modes, and weather applicable to geographical location of the base station; provision of a monitored behavior of the component temperature as a function of one or more of: the monitored traffic load, the monitored used operational modes, and the monitored weather applicable to geographical location of the base station; and prediction of the behavior of the component temperature based on the monitored behavior of the component temperature.

18. The apparatus of any of claims 16 through 17, wherein prediction of the behavior of the component temperature comprises prediction that the behavior of the component temperature during the upcoming time interval will correspond to a behavior of the monitored component temperature during one or more previous time intervals.

19. The apparatus of any of claims 16 through 18, wherein the controlling circuitry is further configured to cause: estimation of the lifetime of the component based on the monitored behavior of the component temperature; and prevention of the base station from operating in any operational mode having associated power consumption that is lower than the third threshold value only when the estimated lifetime is shorter than a fourth threshold value.

20. The apparatus of claim 19, wherein estimation of the lifetime of the component is further based on a predicted traffic growth.

21. The apparatus of any of claims 19 through 20, wherein the controlling circuitry is further configured to cause, when the estimated lifetime is shorter than the fourth threshold value, one or more of: enforcement of traffic load reduction for the base station; and enforcement of a transmission power reduction for the base station.

22. A network node comprising the apparatus of any of claims 12 through 21.

23. The network node of claim 22, wherein the network node is the base station.