Context triggered power control for sidelink

Abstract

Mechanisms for context-triggered power control for a sidelink between a first UE and a second UE are provided. A method is performed by the first UE. The method includes controlling a transmit power of the sidelink in accordance with a transmit context in which a transmission on the sidelink is made.

Description

TECHNICAL FIELD

[0001] Embodiments presented herein relate to a method, a user equipment (UE), a computer program and a computer program product for context triggered power control for a sidelink between a first UE and a second UE. BACKGROUND

[0002] In a communication network, there can be challenges to obtain good performance and capacity for a given communication protocol, parameters of the communication network and physical environment in which the communication network is deployed.

[0003] For example, sidelink communication enables two or more proximate devices, such as two UEs, to communicate with each other without the need for a radio access network node, such as a base station. Sidelink communication can be used for out-of-network coverage scenarios, but also for scenarios where both devices are within network coverage. Thus, this functionality can also be used in combination with a traditional cellular network connection.

[0004] One aspect of sidelink communication concerns which sidelink transmission mode the devices involved in the sidelink communication should use. For example, depending on the selected sidelink transmission mode and depending on a transmission power control (TPC) command in a downlink control information 5 (DCI 5), as transmitted from a radio access network node, the UE is commanded to obey different power control manners. For example, assuming the TPC command is set to "0", power control is basically removed and the UE is commanded to operate at maximum transmission power. The maximum allowed power for the control channel of the sidelink and the maximum allowed power for the data channel of the sidelink are cell-specific or pre-configured. For example, assuming the TPC command is set to "1", the UE is commanded to adjust the sidelink transmission power of the UE in relation to the path loss of the access link between the UE and the radio access network node. Such power control schemes are further described in detail in 3GPP TS 36.213 V15.7.0, in section 14.1.1.5 considering "UE procedure for PSSCH power control" and in section 14.2.1.3 considering "UE procedure for PSCCH power control".

[0005] Sidelink transmission power P SL may be summarized as:

[0006] ,

[0007] wherein PMAX represents a maximum power level value for transmissions on the sidelink 160, M represents a bandwidth of a resource allocation expressed in number of resource blocks, where the bandwidth is provided by a higher layer parameter associated with the corresponding resource configuration P O and the value of a, and where represents a sidelink path loss value. However, in some cases, this expression does not correctly reflect the required sidelink transmission power.

[0008] Hence, there is still a need for improved control of sidelink transmission power. SUMMARY

[0009] It is an object of embodiments herein to provide efficient control of sidelink transmission power.

[0010] According to a first aspect, a method for context triggered power control of a sidelink between a first UE and a second UE is presented. The method is performed by the first UE. The method comprises controlling a transmission power of the sidelink in dependence of a transmission context in which a transmission on the sidelink is triggered.

[0011] According to a second aspect, a UE for context triggered power control of a sidelink between the UE and a second UE is presented. The UE comprises processing circuitry and a storage medium containing instructions executable by the processing circuitry, such that the UE is operative to control a transmission power of the sidelink in dependence of a transmission context in which a transmission on the sidelink is triggered.

[0012] According to a third aspect, a UE for context triggered power control of a sidelink between the UE and a second UE is presented. The UE comprises a control module configured to control a transmission power of the sidelink in dependence of a transmission context in which a transmission on the sidelink is triggered.

[0013] According to a fourth aspect, a computer program for context triggered power control of a sidelink between a first user equipment, UE, and a second UE is presented. The computer program comprises computer code which, when run on processing circuitry of the first UE, causes the first UE to control a transmission power of the sidelink in dependence of a transmission context in which a transmission on the sidelink is triggered.

[0014] According to a fifth aspect, a computer program product comprises a computer program according to the fourth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium can be a non-transitory computer readable storage medium.

[0015] Advantageously, these aspects provide for an efficient control of the sidelink transmission power.

[0016] Advantageously, by controlling the sidelink transmission power according to these aspects, the amount of interference generated by sidelink transmissions can be reduced.

[0017] Advantageously, with the amount of interference reduced, the frequency spectrum can be used more efficiently, e.g. by using the same frequency band for sidelink transmissions in different geographical areas within one cell at the same time.

[0018] Other objects, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, the appended dependent claims, and the accompanying drawings.

[0019] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined herein. All references to a / an / the [element, device, component, means, step, etc.] are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The actions recited in any of the methods disclosed herein need not be performed in the exact order disclosed herein unless explicitly stated as such. BRIEF DESCRIPTION OF DRAWINGS

[0020] The concepts of the present application will now be described, by way of example, with reference to the accompanying drawings, in which:

[0021] Figure 1 is a schematic diagram illustrating a communication network according to an embodiment;

[0022] Figure 2 is a flowchart of a method according to an embodiment;

[0023] Figure 3 schematically illustrates a transmission power ramping scheme according to an embodiment;

[0024] Figure 4 is a schematic diagram illustrating functional units of a UE according to an embodiment;

[0025] Figure 5 is a schematic diagram illustrating functional modules of a UE according to an embodiment;

[0026] Figure 6 shows one example of a computer program product comprising a computer-readable storage medium according to an embodiment;

[0027] Figure 7 is a schematic diagram illustrating a telecommunication network connected via an intermediate network to a host computer according to some embodiments; and

[0028] Figure 8is a schematic diagram illustrating a host computer communicating via a radio base station with a terminal device over a partially wireless connection, in accordance with some embodiments. DETAILED DESCRIPTION

[0029] The present inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventive concepts are shown. The inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concepts to those skilled in the art. Like reference numerals refer to like elements throughout the specification. Any dashed lines show optional features.

[0030] Figure 1 is a schematic diagram illustrating a communication network 100a in which embodiments presented herein can be applied. The communication network 100a can be a third generation (3G) telecommunication network, a fourth generation (4G) telecommunication network, a fifth generation (5G) telecommunication network, or any upgrade thereof, and support any 3GPP telecommunication standard, where applicable.

[0031] The communication network 100a comprises a radio access network node 140 configured to provide network access to UEs 200a, 200b in a radio access network 110. The radio access network 110 is operatively connected to a core network 120. The core network 120 is in turn operatively connected to a service network 130, such as the Internet. The UEs 200a, 200b are thereby enabled to access services of the service network 130 and exchange data with the service network 130. The operations of accessing services and exchanging data are performed via the radio access network node 140. The radio access network node 140 comprises a transmission and reception point (TRP), is collocated with, integrated with, or in operative communication with the transmission and reception point (TRP). The radio access network node 140 (via its TRP) and the UEs 200a, 200b are configured to communicate with each other over access links 150a, 150b. In this regard, the UE 200b can be outside the coverage of the radio access network node 140, as illustrated by the access link 150b drawn with a dashed line. Further, the UEs 200a, 200b are configured to communicate with each other over a sidelink 160.

[0032] Examples of radio access network nodes 140 are radio base stations, base transceiver stations, Node Bs (NBs), evolved Node Bs (eNBs), gNBs, access points, access nodes, and backhaul nodes. Examples of UEs 200a, 200b are wireless devices, mobile stations, mobile phones, handsets, wireless local loop phones, smart phones, laptop computers, tablet computers, network-equipped sensors, network-equipped vehicles, and so-called Internet of Things devices. In some embodiments, UEs 200a, 200b are part of, collocated with, or integrated in respective vehicles.

[0033] In the following, UE 200a will be denoted as first UE, while UE 200b will be denoted as second UE. However, this does not necessarily imply that there is any hierarchical relationship between these UEs 200a, 200b or any other UEs. Likewise, UE 200b can assume the role of first UE, and UE 200a can assume the role of second UE.

[0034] As mentioned above, there is still a need for improved control of sidelink transmission power. In some scenarios, it can be beneficial to control the sidelink transmission power also based on other parameters than the parameters included in the cited expression for sidelink transmission power With respect to the above-mentioned expression for sidelink transmission power With respect to the above-mentioned expression for sidelink transmission power

[0035] In more detail, in a typical scenario, the first UE 200a can use the maximum transmission power transmit a message in the sidelink 160 to ensure that all intended responders, such as the second UE 200b, receive the transmission. In case the transmission is due to an emergency situation, this can be considered acceptable. In other situations, from the perspective of the first UE 200a, the transmission power will only take into account the path loss to the radio access network node 140, as indicated by the term .

[0036] Consider for example a situation where a first vehicle (equipped with a first UE 200a) approaches a road intersection where a possible collision occurs. It can be beneficial if the vehicle can contact other vehicles located in the vicinity of the first vehicle (equipped with a second UE 200b), also approaching the same intersection, by means of transmitting messages on the sidelink 160. At the same time, however, the first vehicle need not contact those vehicles that are far away and / or not approaching the intersection. This requires that the transmission power of the sidelink 160 is controlled correctly. However, it is not possible to control the transmission power in such a way by only considering the path loss to the radio access network node 140, since the path loss to the radio access network node 140 generally does not represent either the distance between the first vehicle and the intersection, or the speed at which the first vehicle is approaching the intersection, unless the radio access network node 140 is placed directly at the intersection (which normally cannot be considered to be the case).

[0037] Embodiments disclosed herein thus relate to mechanisms for context-triggered power control for a sidelink 160 between a first UE 200a and a second UE 200b. To obtain such mechanisms, a first UE 200a, a method performed by the first UE 200a, a computer program product comprising code, e.g. in the form of a computer program, which when run on the first UE 200a causes the first UE 200a to perform the method are provided.

[0038] At least some of the embodiments disclosed herein are based on adapting the sidelink transmission power to the current situation considered for the sidelink transmission. Information accessible to the first UE 200a about the current situation (for what intended purpose the sidelink transmission is started, what application triggered the sidelink transmission, etc.) can be used by the first UE 200a when selecting the transmission power of the sidelink 160. The first UE 200a can thus ensure that the sidelink transmission will reach the response area reflecting the transmission purpose.

[0039] Figure 2 is a flowchart illustrating embodiments of methods for context-triggered power control for a sidelink 160 between a first UE 200a and a second UE 200b. The methods are performed by the first UE 200a. Advantageously, the methods are provided as a computer program 620.

[0040] The transmission power of the sidelink 160 is selected in dependence of the transmission context. In particular, the first UE 200a is configured to perform an action S102:

[0041] S102: The first UE 200a controls the transmission power of the sidelink 160 in dependence of the transmission context in which the transmission on the sidelink 160 is triggered.

[0042] Examples of such transmission context and current conditions in which sidelink transmissions are to take place will be provided below.

[0043] Embodiments relating to further details of the power control context triggered by the first UE 200a for the sidelink 160 between the first UE 200a and the second UE 200b will now be disclosed.

[0044] In some embodiments, it is assumed that the intended receiver defined by the second UE 200b receives the transmission on the sidelink 160. However, in other embodiments, the second UE 200b does not receive the transmission on the sidelink 160. There can be different ways for the first UE 200a to handle the latter case. Different embodiments relating to this will now be described in turn.

[0045] In some embodiments, when the first UE 200a does not receive any response from the second UE 200b indicating that the second UE 200b has received the transmission on the sidelink 160, the first UE 200a ramps up the transmission power in order to further transmit the same message on the sidelink 160, e.g. in order to make one or more retransmissions. In particular, in some embodiments, in case of no response to the message transmission on the sidelink 160 within a predetermined time period, the first UE 200a is configured to perform the (optional) action S104:

[0046] S104: The first UE 200a retransmits the message on the sidelink 160 while applying a transmission power ramping scheme. According to the transmission power ramping scheme, the transmission power used for retransmitting the message is controlled to increase with each retransmission of the message.

[0047] In Figure 2 This is illustrated by a feedback loop from action S104 to itself in

[0048] The proposed power ramping scheme enables the first UE 200a to approach a connection setup from a more conservative starting point from a transmission power perspective. Thus, the first UE 200a is enabled to start with a lower transmission power level and then gradually increase the transmission power according to the power ramping scheme in case of no response from the second UE 200b.

[0049] In some embodiments, the power ramping scheme parameters are selected according to the transmission context. That is, in some embodiments, at least one of how much the transmission power is increased with each retransmission and how fast the increase is made depends on the transmission context.

[0050] In this respect, the predetermined time period can take a fixed value or be dependent on the transmission context, such that for a transmission context indicating a high urgency level, the predetermined time period is shorter than for a transmission context indicating a low urgency level.

[0051] In this respect further, the number of retransmissions can be fixed or dependent on the transmission context, such that for a transmission context indicating a high urgency level, the number of retransmissions is higher than for a transmission context indicating a low urgency level.

[0052] In this respect further, the increase of the transmission power from one retransmission to the next retransmission can be dependent on the sequence number of the retransmission attempt. That is, in some embodiments, at least one of how much the transmission power is increased and how fast the transmission power is increased per retransmission is dependent on how many retransmissions of the message have already been made.

[0053] Reference is made here to Figure 3 , Figure 3 Three examples of transmission power ramping schemes (a), (b), (c) are schematically shown. In Figure 3 , it is shown how the transmission power is increased at different rates over time for different transmission power ramping schemes (a), (b), (c). As an example for the transmission power ramping scheme (a), for the first transmission (i.e. retransmission zero), a transmission power value of 2.5 is used. Then, after 2.5 time units, the transmission power is increased to a transmission power value of 4, and so on. Thus, if a retransmission is to occur at a time point between time value 0 and time value 2.5, the transmission power is set according to the transmission power value of 2.5, and so on. In this respect, the transmission power ramping scheme (a) represents a moderate increase of the transmission power, whereas the transmission power ramping scheme (c) represents the most aggressive increase of the transmission power, and the transmission power ramping scheme (b) represents the most lenient increase of the transmission power. As will be understood by the skilled person, these are merely three examples of transmission power ramping schemes, and other transmission power ramping schemes are equally possible.

[0054] The proposed power ramping scheme can be mathematically expressed as follows:

[0055]

[0056] In this expression, is the transmission power for the (re)transmission attempt , and thus is the transmission power for the next retransmission (i.e. for the retransmission attempt ). Furthermore, is the power increase, wherein the power increase is a function of the transmission context and the sequence number given by the retransmission attempt number .f to be defined.

[0057] In some embodiments, the power ramping scheme is adaptively adjusted when the transmission context is updated. That is, in some embodiments, when the transmission context is updated, the transmission power ramping scheme is adjusted according to the updated transmission context. This means that, when the transmission context is updated, either the increase in transmission power from one retransmission to the next is adjusted to be more aggressive (e.g. such that the increase in transmission power from one retransmission to the next is higher than it was before the transmission power ramping scheme was adjusted), or it is adjusted to be less aggressive (e.g. such that the increase in transmission power from one retransmission to the next is lower than it was before the transmission power ramping scheme was adjusted).

[0058] In a first phase, the first UE 200a uses a first transmission power ramping scheme (say, the transmission power ramping scheme (a)) for retransmitting the message according to a first transmission context. In a second phase, the first UE 200a identifies that the transmission context has changed to a second transmission context. In a third phase, if no response to the message is received, retransmission of the message continues, but using a second transmission power ramping scheme (say, the transmission power ramping scheme (b) or (c)) selected according to the second transmission context. In the first example, even if the transmission context changes, the transmission power does not decrease from one retransmission to the next. Thus, in Figure 3 , assume that the transmission power ramping scheme (a) is used and the transmission context changes such that a new transmission power ramping scheme is to be used at time value 6. Then, at time value 6, the transmission power will either remain at power value 3 (if the transmission power ramping scheme (b) is used) or increase to power value 7.5 (using the transmission power ramping scheme (c)). In the second example, if the transmission context changes, the transmission power is allowed to decrease from one retransmission to the next. Thus, in Figure 3 , again assume that the transmission power ramping scheme (a) is used and the transmission context changes such that a new transmission power ramping scheme is to be used at time value 6. Then, at time value 6, the transmission power will either be decreased to power value 3 (if the transmission power ramping scheme (b) is used) or increased to power value 7.5 (using the transmission power ramping scheme (c)). Figure 3 Figure 3

[0059] ​​Generally, the transmission on the sidelink 160 involves the transmission of one or more messages. Each message can comprise data (such as PSSCH signaling, where PSSCH is short for Physical Sidelink Shared Channel) or control information (such as PSCCH signaling, where PSCCH is short for Physical Sidelink Control Channel). In addition to the data or control information, the message can comprise additional information, such as information about the cause. Such information can be considered by the second UE 200b in its possible future response to the message transmitted by the first UE 200a.

[0060] In some embodiments, the message comprises information about what caused the sidelink transmission. That is, in some embodiments, when controlling the transmission power, the message transmitted on the sidelink 160 comprises information indicating the transmission context. For example, the information indicating the transmission context can be given in a textual format and specifies that the message belongs to the type "critical", "length-critical", "time-critical", "time / length-critical", "moderate" or "casual", etc. For example, the information indicating the transmission context can be given in terms of a numerical value defining one or more of the following: the expected distance of the sidelink transmission, the time scale of the sidelink transmission (i.e. the time criticalness), etc. Thus, in preferred embodiments, the transmission context can be represented by a value, wherein the value encodes at least one transmission condition. Preferably, the value is from a set of values, and each value in the set encodes at least one transmission condition. The value can be a numerical value or a descriptive value. The transmission condition can be a condition that triggers the sidelink transmission and / or a condition that occurs at the time of the transmission (e.g. related to the propagation of the radio signal). For example, in a storm, the propagation conditions will be different from the propagation conditions in a sunny day, and this can require the application of a different power ramping scheme.

[0061] In some embodiments, the message comprises a sequence number. That is, in some embodiments, when retransmitting a message on the sidelink 160, the message comprises an indicator about how many times the message has been retransmitted.

[0062] In some embodiments, the message comprises transmission power information. That is, in some embodiments, the message comprises information about the transmission power level used to transmit the message.

[0063] With this information, the second UE 200b can adjust parameters of any future response to the message so that, for example, distance and / or time scale constraints can be met. The distance constraints can define which transmit power is to be used for the transmission on the sidelink 160 and possibly which transmit power ramping scheme is to be used, while the time scale constraints can define when the response to the message needs to be transmitted on the sidelink 160 and possibly which transmit power ramping scheme is to be used. In some embodiments, the message comprises a combination of two or more of the information examples disclosed above.

[0064] As disclosed above, the first UE 200a controls the transmit power of the sidelink 160 in S102 in dependence on a transmission context in which the transmission on the sidelink 160 is triggered. Thus, in this respect, there can be different examples of transmission contexts. Embodiments related thereto will now be disclosed.

[0065] In some embodiments, the sidelink transmission is triggered by an application running in the first UE 200a and the application defines the transmission context. That is, in some embodiments, the transmission context can indicate the application in the first UE 200a that triggered the sidelink transmission.

[0066] In some embodiments, the sidelink transmission is associated with an indication of how urgent the transmission of the sidelink transmission is and the indication defines the transmission context. That is, in some embodiments, the transmission context can indicate a time critical nature of the sidelink transmission.

[0067] In some embodiments, the sidelink transmission is to reach any UE located at a specific target location, such as a street intersection, from the first UE 200a and the distance to the target location defines the transmission context. That is, in some embodiments, the transmission context can indicate a distance between the first UE 200a and the target location of the sidelink transmission.

[0068] In some embodiments, the sidelink transmission is to reach any UE located at a specific distance from the first UE 200a and the distance defines the transmission context. That is, in some embodiments, the transmission context can indicate a relative distance between the first UE 200a and the second UE 200b.

[0069] In some embodiments, the sidelink transmission is performed while the UE 200a is travelling at a specific speed and the speed defines the transmission context. That is, in some embodiments, the transmission context can indicate an absolute speed of the first UE 200a.

[0070] In some embodiments, the sidelink transmission is to reach other UEs also travelling at a certain speed, which can be the same or different from the speed of the first UE 200a. Thus, in some embodiments, the first UE 200a and the second UE 200b travel relative to each other at a relative speed, which defines the transmission context. That is, in some embodiments, the transmission context can be indicative of the relative speed between the first UE 200a and the second UE 200b.

[0071] In some embodiments, the transmission context can be indicative of a combination of two or more of the preceding embodiments. In particular, in some embodiments, the transmission context can be indicative of a combination of the relative distance between the first UE 200a and the second UE 200b and the relative speed between the first UE 200a and the second UE 200b.

[0072] Figure 4 The components of the UE 200a according to embodiments are schematically shown in terms of a number of functional units. The processing circuitry 210 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 610 (as shown), such as in the form of a storage medium 230, (e.g., a Figure 6 memory, etc.), to provide the functionality described herein. The processing circuitry 210 can further be provided as at least one dedicated integrated circuit (ASIC), or field programmable gate array (FPGA).

[0073] In particular, the processing circuitry 210 is configured to cause the UE 200a to perform a set of operations or actions as disclosed above. For example, the storage medium 230 can store the set of operations, and the processing circuitry 210 can be configured to retrieve the set of operations from the storage medium 230 to cause the UE 200a to perform the set of operations. The set of operations can be provided as a set of executable instructions.

[0074] Thus, the processing circuit 210 is thereby arranged to perform the methods disclosed herein. The storage medium 230 can also comprise persistent storage, which, as earlier mentioned, can be any single one or combination of magnetic storage, optical storage, solid state storage or even remotely mounted storage. The UE 200a can further include a communication interface 220 configured at least for communication with a radio access network node 140 over an access link 150a, 150a', and with another UE 200b over a sidelink 160. As such, the communication interface 220 can comprise one or more transmitters and receivers, including analogue and digital components. The processing circuit 210 controls the general operation of the UE 200a, e.g. by sending data and control signals to the communication interface 220 and the storage medium 230, by receiving data and reports from the communication interface 220, and by retrieving data and instructions from the storage medium 230. Other components and their related functionality are omitted in order not to obscure the concepts presented herein.

[0075] Figure 5 The components of the UE 200a according to embodiments are schematically illustrated in terms of a number of functional modules. Figure 5 The UE 200a comprises a control module 210a configured to perform the action S102. Figure 5 The UE 200a can further comprise a number of optional functional modules, such as a transmitting module 210b configured to perform the action S104. In general terms, each functional module 210a-210b can in one embodiment be implemented in hardware only, while in another embodiment it can be implemented by means of software, i.e. the latter embodiment has computer program instructions stored on the storage medium 230 which, when run on the processing circuitry, causes the UE 200a to perform the corresponding actions mentioned above in connection with the Figure 5 It should also be mentioned that even if these modules correspond to parts of a computer program, they do not need to be separate modules in that the way they are implemented in software depends on the programming language. Preferably, one or more or all of the functional modules 210a-210b can be implemented by the processing circuitry 210, possibly in cooperation with the communication interface 220 and / or the storage medium 230. Thus, the processing circuitry 210 can be configured to fetch instructions provided by the functional modules 210a-210b from the storage medium 230 and execute these instructions, thereby performing any of the actions disclosed herein.

[0076] UE 200a may be provided as a standalone device or as part of at least one other device. Examples of different types of UEs have been provided above. For example, as disclosed above, UE 200a may be part of a vehicle, commingled with a vehicle, or integrated with a vehicle.

[0077] The first portion of the instructions executed by UE 200a may be executed in a first device, and the second portion of the instructions executed by UE 200a may be executed in a second device; the embodiments disclosed herein are not limited to any particular number of devices on which the instructions executed by UE 200a can be executed. Therefore, the method according to the embodiments disclosed herein is suitable for execution by UE 200a residing in a cloud computing environment. Therefore, although in Figure 4 A single processing circuit 210 is shown, but processing circuits 210 can be distributed among multiple devices or nodes. The same applies to... Figure 5 Functional modules 210a-210b and Figure 6 Computer program 620.

[0078] Figure 6 An example of a computer program product 610 including a computer-readable storage medium 630 is shown. On this computer-readable storage medium 630, a computer program 620 may be stored, which may cause processing circuitry 210 and entities and means operatively coupled to said processing circuitry 210 (such as a communication interface 220 and a storage medium 230) to perform the methods according to the embodiments described herein. Thus, computer program 620 and / or computer program product 610 may provide components for performing any of the actions disclosed herein.

[0079] exist Figure 6 In the example, computer program product 610 is shown as an optical disc, such as a CD (compressed disc), DVD (Digital Universal Disc), or Blu-ray disc. Computer program product 610 can also be implemented as a memory, such as random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM), and more specifically, computer program product 610 can also be implemented as a flash memory (such as a small flash memory) or a non-volatile storage medium in an external memory device (such as a USB (Universal Serial Bus) memory). Therefore, although computer program 620 is schematically shown herein as a track on the illustrated optical disc, computer program 620 can be stored in any manner suitable for computer program product 610.

[0080] Figure 7is a schematic diagram illustrating a telecommunication network connected via an intermediate network 420 to a host computer 430, according to some embodiments. The communication system includes a telecommunication network 410, such as a 3GPP-type cellular network, which comprises an access network 411, such as Figure 1 a radio access network 110 in Figure 1 a core network 414, such as Figure 1 the core network 120 in Figure 1 The access network 411 comprises a plurality of radio access network nodes 412a, 412b, 412c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area or cell 413a, 413b, 413c. Each radio access network node 412a, 412b, 412c is connectable to the core network 414 over a wired or wireless connection 415. A first UE 491 located in coverage area 413c is configured to wirelessly connect to, or be paged by, the corresponding network node 412c. A second UE 492 in coverage area 413a is wirelessly connectable to the corresponding network node 412a. While a plurality of UEs 491, 492 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is either in the coverage area or connects to the corresponding network node 412. The UEs 491, 492 correspond to

[0081] the UEs 200a, 200b of

[0082] The telecommunication network 410 is itself connected to a host computer 430, which can be implemented as a server, a cloud implementation, a distributed system, or as a server farm, and / or software thereof, or as processing resource(s) in a server farm. The host computer 430 can be owned or controlled by the service provider, or can be operated or at least partly operated by the service provider. The connections 421, 422 between the telecommunication network 410 and the host computer 430 can extend directly from the core network 414 to the host computer 430 or can go via an optional intermediate network 420. The intermediate network 420 can be one or a combination of several of the following: a public, private or hosted network; the intermediate network 420, if any, can be a backbone network or the Internet; in particular, the intermediate network 420 can comprise two or more sub-networks (not shown). Figure 7The communication system as a whole enables connectivity between the connected UEs 491, 492 and the host computer 430. The connectivity can be described as an over-the-top (OTT) connection 450. The host computer 430 and the connected UEs 491, 492 are configured to communicate data and / or signaling over the OTT connection 450 using the access network 411, the core network 414, any intermediate network 420 and possible further infrastructure (not shown) as intermediaries. The OTT connection 450 can be transparent in the sense that the

[0083] In one embodiment, an OTT service related to highway traffic control can use sidelink communication between vehicles on a highway. Other OTT services using OTT communication are also conceivable.

[0084] Figure 8 is a schematic diagram illustrating a host computer communicating via a radio access network node with a UE over a partially wireless connection in accordance with some embodiments. Reference will now be made to Figure 8 Example implementations of the UE, the radio access network node and the host computer discussed in the preceding paragraphs will now be described with reference to the Figure 1UE 200a, 200b. When providing services to remote users, host application 512 can provide user data transmitted using OTT connection 550.

[0085] The communication system 500 also includes a radio access network node 520 provided in the telecommunications system, and includes hardware 525 enabling the radio access network node 520 to communicate with the host computer 510 and the UE 530. The radio access network node 520 corresponds to... Figure 1 The radio access network node 140. Hardware 525 may include: a communication interface 526 for establishing and maintaining wired or wireless connections with interfaces of different communication devices of the communication system 500; and a radio interface 527 for establishing and maintaining connections with the coverage area served by the radio access network node 520. Figure 8 At least a wireless connection 570 of UE 530 (not shown). Communication interface 526 can be configured to facilitate a connection 560 to host computer 510. Connection 560 can be direct, or it can be via the core network of the telecommunications system ( Figure 8 (Not shown) and / or via one or more intermediate networks outside the telecommunications system. In the illustrated embodiment, the hardware 525 of the radio access network node 520 also includes processing circuitry 528, which may include one or more programmable processors, application-specific integrated circuits, field-programmable gate arrays, or combinations thereof (not shown) suitable for executing instructions. The radio access network node 520 also has software 521 stored internally or accessible via an external connection.

[0086] The communication system 500 further includes the UE 530 already referred to. The UE 530 has hardware 535 enabling it to communicate with the host computer 510, e.g. by setting up a wireless connection 570. The hardware 535 of the UE 530 further includes processing circuitry 538, which can comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 530 further comprises software 531, which is stored in or accessible by the UE 530 and executable by the processing circuitry 538. The software 531 includes a client application 532. The client application 532 can be operable to provide the user with a service, with which the user can interact via the UE 530. The client application 532 can communicate with the host computer 510, e.g. with a host application 512 executing on the host computer 510, via the OTT connection 550 terminating at the UE 530 and the host computer 510. In providing the service to the user, the client application 532 can receive request data from the host computer 510 and provide user data in response to the request data. The OTT connection 550 can transmit both the request data and the user data. The client application 532 can generate the user data by interacting with the user, e.g. with the user operating the UE 530.

[0087] It is noted that the host computer 510, radio access network node 520 and UE 530 illustrated in Figure 8 may be similar or identical to the host computer 430, one of the network nodes 412a, 412b, 412c and one of the UEs 491, 492 of Figure 7 . This is to say, the inner workings of these entities can be as illustrated in Figure 8 and independently, the surrounding network topology can be that of Figure 7 .

[0088] In Figure 8 , the OTT connection 550 has been drawn abstractly to illustrate the communication between the host computer 510 and the UE 530 via the network node 520, without any implication regarding the nature and function of the intermediary devices and the precise routing of messages via these devices. The network infrastructure can determine the routing of messages

[0089] The wireless connection 570 between the UE 530 and the radio access network node 520 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 530 using the OTT connection 550, in which the wireless connection 570 forms the last segment. More precisely, the teachings of these embodiments can reduce interference due to improved categorization of airborne UEs, which can generate significant interference.

[0090] A measurement procedure can be provided for the purpose of monitoring the data rate, latency and other factors on which the one or more embodiments improve. There can further be an optional network functionality to reconfigure the OTT connection 550 between the host computer 510 and the UE 530, in response to variations in the measurement results. The measurement procedure and / or the network functionality to reconfigure the OTT connection 550 can be implemented in the software 511 and the hardware 515 of the host computer 510 or in the software 531 and the hardware 535 of the UE 530, or both. In embodiments, sensors (not shown) can be deployed in or in association with the communication devices through which the OTT connection 550 traverses; the sensors can participate in the measurement procedure by providing values of the monitored quantities exemplified above, or providing values of other physical quantities from which software 511, 531 can compute or estimate the monitored quantities. The reconfiguring of the OTT connection 550 can include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not affect the radio access network 520, and it can be unknown or imperceptible to the radio access network 520. Such procedures and functionality can be known and practiced in the art. In certain embodiments, measurements can involve proprietary UE signaling facilitating the host computer's 510 measurements of throughput, propagation times, latency, and the like. The measurements can be implemented in the software 511, 531, which causes messages to be transmitted using the OTT connection 550 while it monitors propagation times, errors, and so on.

[0091] The concepts of the present application have mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concepts, which are defined by the appended patent claims.

Claims

1. A method for context-triggered power control of a sidelink between a first user equipment, UE, and a second UE, the method being performed by the first UE, the method comprising: controlling a transmission power of the sidelink in dependence on a transmission context in which a transmission on the sidelink is triggered, wherein, in case of no response to a transmission of a message on the sidelink within a predetermined time period, the method further comprises: retransmitting the message on the sidelink while applying a transmission power ramping scheme, wherein according to the transmission power ramping scheme, the transmission power for retransmitting the message is controlled to increase with each retransmission of the message, wherein at least one of how much and how fast the transmission power is increased with each retransmission is in dependence on the transmission context.

2. The method of claim 1, wherein, at least one of how much and how fast the transmission power is increased with each retransmission is in dependence on how many retransmissions of the message have been made.

3. The method of claim 1, wherein, the transmission power ramping scheme is adjusted in dependence on an update of the transmission context.

4. The method of any one of claims 1-3, wherein, the message transmitted on the sidelink comprises information indicative of the transmission context.

5. The method of any one of claims 1-3, wherein, the message retransmitted on the sidelink comprises an indicator on how many times the message has been retransmitted.

6. The method of claim 4, wherein, the message comprises information on a transmission power level used for transmitting the message.

7. The method of any one of claims 1-3, wherein, the transmission context is indicative of an application in the first UE that triggered the sidelink transmission.

8. The method of any one of claims 1-3, wherein, the transmission context is indicative of the sidelink transmission being time-critical.

9. The method of any one of claims 1-3, wherein, the transmission context is indicative of a distance between the first UE and a target location of the sidelink transmission.

10. The method of any one of claims 1-3, wherein, the transmission context is indicative of a relative distance between the first UE and the second UE.

11. The method of any one of claims 1-3, wherein, the transmission context is indicative of an absolute speed of the first UE.

12. The method of any one of claims 1-3, wherein, the transmission context is indicative of a relative speed between the first UE and the second UE.

13. The method of any one of claims 1-3, wherein, the transmission context is indicative of a combination of a relative distance between the first UE and the second UE and a relative speed between the first UE and the second UE.

14. The method of any one of claims 1-3, wherein, each of the first UE and the second UE is part of a respective vehicle.

15. The method of any one of claims 1-3, wherein, the transmission context is represented by a value from a set of values, wherein each of the values is used to encode at least one transmission condition.

16. A user equipment, UE, for context-triggered power control of a sidelink between the UE and a second UE, the UE comprising processing circuitry and a storage medium, the storage medium containing instructions executable by the processing circuitry such that the UE is operable to: control a transmission power of the sidelink in dependence on a transmission context in which a transmission on the sidelink is triggered; and in case of no response to a transmission of a message on the sidelink within a predetermined time period, retransmit the message on the sidelink while applying a transmission power ramping scheme, wherein according to the transmission power ramping scheme, the transmission power for retransmitting the message is controlled to increase with each retransmission of the message, wherein At least one of how much and how fast the transmission power is increased with each retransmission is dependent on the transmission context.

17. The UE of claim 16, the UE being further configured to perform the method of any one of claims 2 to 15.

18. A user equipment, UE, for context-triggered power control for a sidelink between the UE and a second UE, the UE comprising: a control module for controlling a transmission power of the sidelink in dependence on a transmission context in which a transmission on the sidelink is triggered, wherein, in case of no response to a transmission of a message on the sidelink within a predetermined time period, the control module is further configured to retransmit the message on the sidelink while applying a transmission power ramping scheme, wherein according to the transmission power ramping scheme the transmission power for retransmitting the message is controlled to increase with each retransmission of the message, wherein at least one of how much and how fast the transmission power is increased with each retransmission is dependent on the transmission context.

19. The UE of claim 18, the UE being configured to perform the method of any one of claims 2 to 15.

20. A computer-readable storage medium storing a computer program for context-triggered power control for a sidelink between a first user equipment, UE, and a second UE, the computer program comprising computer code which, when run on processing circuitry of the first UE, causes the first UE to perform the method of any one of claims 1 to 15.

21. A computer program product comprising a computer program for context-triggered power control for a sidelink between a first user equipment, UE, and a second UE, the computer program comprising computer code which, when run on processing circuitry of the first UE, causes the first UE to perform the method of any one of claims 1 to 15.

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