WO2020191772A1

WO2020191772A1 - Dynamic threshold for dual-connectivity in unlicensed spectrum

Info

Publication number: WO2020191772A1
Application number: PCT/CN2019/080252
Authority: WO
Inventors: Benoist Sebire; Chunli Wu; Samuli Turtinen
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2019-03-28
Filing date: 2019-03-28
Publication date: 2020-10-01
Also published as: CN113647135B; CN113647135A

Abstract

Example embodiments of the present disclosure relate to a device, method, apparatus and computer readable storage medium for adjusting a split threshold for dual-connectivity in unlicensed spectrum. In example embodiments, a terminal device in dual-connectivity with two cell groups detects a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum. In response to the detection of the number of listen-before-talk failures, the terminal device adjusts a split threshold for splitting uplink data between the two cell groups.

Description

DYNAMIC THRESHOLD FOR DUAL-CONNECTIVITY IN UNLICENSED SPECTRUM

FIELD

Example embodiments of the present disclosure generally relate to the field of communications, and in particular, to a device, method, apparatus and computer readable storage medium for adjusting a split threshold for dual-connectivity in unlicensed spectrum.

BACKGROUND

Listening Before Talk (LBT) regulates communication over the unlicensed spectrum. Only if a channel is sensed free, a transmission can be carried out over the unlicensed spectrum. In a LBT procedure, a device may apply a clear channel assessment (CCA) check before using a channel. The CCA utilizes at least energy detection to determine the presence or absence of other signals on a channel so as to determine whether a channel is occupied or clear. In certain countries and regions, LBT is mandated for the unlicensed spectrum. Apart from regulatory requirements, carrier sensing via LBT is one way for fair sharing of the unlicensed spectrum. Hence, it is considered to be a vital feature for fair and friendly operation in the unlicensed spectrum in a single global solution framework.

For New Radio (NR) unlicensed in the 3rd Generation Partnership Project (3GPP) , agreed objectives include Dual-Connectivity (DC) operation. In DC, a terminal device such as user equipment (UE) maintains two connections with two network devices such as eNBs or gNBs or two cell groups. DC was introduced in 3GPP Release 12 (Rel-12) and enhanced in Release 13 (Rel-13) to support bearer split operation in uplink. When a bearer is split in uplink, a split threshold may be configured to govern how a Packet Data Convergence Protocol (PDCP) entity feeds data to lower layers for transmissions.

In the bearer split operation, if uplink data to be transmitted is less than the split threshold, the data will be transmitted by a terminal device on a primary path in the two cell groups. If the data exceeds the threshold, the data will be split between a primary path and a secondary path in the two cell groups. However, such threshold-based mechanism is too rigid and inflexible.

SUMMARY

In general, example embodiments of the present disclosure provide a device, method, apparatus and computer readable storage medium for adjusting a split threshold for dual-connectivity in unlicensed spectrum.

In a first aspect, a device in dual-connectivity with two cell groups is provided. The device comprises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the device to detect a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum. The device is further caused to adjust a split threshold for splitting uplink data between the two cell groups in response to the detection of the number of listen-before-talk failures.

In a second aspect, a method is provided. In the method, a terminal device in dual-connectivity with two cell groups detects a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum. In response to the detection of the number of listen-before-talk failures, the terminal device adjusts a split threshold for splitting uplink data between the two cell groups.

In a third aspect, there is provided an apparatus comprising means for performing the steps of the method according to the second aspect.

In a fourth aspect, there is provided a computer readable storage medium comprising program instructions stored thereon. The instructions, when executed by a processor of a device, cause the device to perform the method according to the second aspect.

It is to be understood that the summary section is not intended to identify key or essential features of example embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

FIG. 1 illustrates an example scenario in which some example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a flowchart of an example method according to some example embodiments of the present disclosure; and

FIG. 3 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these example embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

As used herein, the term “terminal device” or “user equipment” (UE) refers to any terminal device capable of wireless communications with each other or with the base station. The communications may involve transmitting and/or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over air. In some example embodiments, the UE may be configured to transmit and/or receive information without direct human interaction. For example, the UE may transmit information to the network device on predetermined schedules, when triggered by an internal or external event, or in response to requests from the network side.

Examples of the UE include, but are not limited to, user equipment (UE) such as smart phones, wireless-enabled tablet computers, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , wireless customer-premises equipment (CPE) , sensors, metering devices, personal wearables such as watches etc., and/or vehicles that are capable of communication. For the purpose of discussion, some example embodiments will be described with reference to UEs as examples of the terminal devices, and the terms “terminal device” and “user equipment” (UE) may be used interchangeably in the context of the present disclosure.

As used herein, the term “network device” refers to a device via which services can be provided to a terminal device in a communication network. Examples of the network device may include a relay, an access point (AP) , a transmission point (TRP) , a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a New Radio (NR) NodeB (gNB) , a Remote Radio Module (RRU) , a radio header (RH) , a remote radio head (RRH) , a low power node such as a femto, a pico, and the like.

As used herein, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) : (i) a combination of analog and/or digital hardware circuit (s) with software/firmware and (ii) any portions of hardware processor (s) with software (including digital signal processor (s)) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

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. The term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to” . The term “based on” is to be read as “based at least in part on” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

As used herein, the terms “first” , “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be referred to as a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

For the bearer split operation, a split threshold to control how PDCP data is fed to lower layers for transmissions is configured in 3GPP TS 36.323 as follows.

A simplified threshold mechanism was agreed for NR in 3GPP TS 38.323 as follows.

According to such threshold-based mechanism, if uplink data to be transmitted by the terminal device exceeds the configured threshold, the data will be split between a primary path and a secondary path in two cell groups served by two different network devices in dual-connectivity with the terminal device. One of the two cells may be referred to as Master Cell Group (MCG) , and the other may be referred to as Secondary Cell Group (SCG) . Accordingly, the data received by the two network devices may be reordered to determine the original data transmitted by the terminal device.

However, this conventional threshold-based mechanism is too rigid and inflexible. Considering different scenarios where either MCG or SCG can use licensed or unlicensed spectrum, this mechanism will cause the following problems shown in Table 1 as below:

Table 1

It can be seen that the too rigid threshold would introduce undesirable delays or degrade the overall throughput for the data transmission in any scenario. The split threshold and/or a primary path may be reconfigured by a network device via Radio Resource Control (RRC) signaling. However, this reconfiguration is deemed to be too slow.

Example embodiments of the present disclosure provide a dynamic threshold mechanism for uplink bearer split operation over the unlicensed spectrum. This dynamic mechanism can reflect LBT failures in the unlicensed spectrum. When a terminal device is in dual-connectivity with two cell groups, if the terminal device detects a number of LBT failures for UL transmission in one of the cell groups over the unlicensed spectrum, the terminal device will adjust a split threshold for splitting uplink data between the two cell groups. As such, a part of the uplink data to be routed to the cell group in which the LBT failures is detected may be reduced.

For example, if a primary cell group of the two cell groups operates in the unlicensed spectrum, the LBT failures in the primary cell group will trigger the split threshold to be reduced. Conversely, when a secondary cell group of the two cell groups operates in the unlicensed spectrum, the LBT failures in the secondary cell group will trigger the split threshold to be increased. As such, the split threshold may be dynamically adjusted based on availability of channels or carriers in the unlicensed spectrum.

FIG. 1 shows an example environment 100 in which example embodiments of the present disclosure can be implemented. The environment 100, which may be a part of a communication network, comprises a terminal device 105 in dual-connectivity with two

network devices

110 and 115. It is to be understood that one terminal device and two network devices are shown in the environment 100 only for the purpose of illustration, without suggesting any limitation to the scope of the present disclosure. Any suitable number of network devices and terminal devices may be included in the environment 100.

The network device 110 holds a cell group 120 and serves the terminal device 105 in the cell group 120. The network device 115 holds a cell group 125 and serves the terminal device 105 in the cell group 125. The

cell groups

120 and 125 may include a plurality of cells for supporting Carrier Aggregation (CA) and can operate in the licensed or unlicensed spectrum.

One of the

network devices

110 and 115 may be a master network device, and the other may be a secondary network device. Accordingly, the cell group provided by the master network device is MCG, and the cell group provided by the secondary network device is SCG. Either MCG or SCG may be primary. Moreover, either the

cell group

120 or 125 maybe MCG.

The terminal device 105 can communicate with the network device 110 in the cell group 120 and with the network devicell5 in the cell group 125 or with another terminal device (not shown) directly or via the

network device

110 or 115. The communication may follow any suitable communication standards or protocols such as Universal Mobile Telecommunications System (UMTS) , long term evolution (LTE) , LTE-Advanced (LTE-A) , the fifth generation (5G) NR, Wireless Fidelity (Wi-Fi) and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiplexing (OFDM) , time division multiplexing (TDM) , frequency division multiplexing (FDM) , code division multiplexing (CDM) , Bluetooth, ZigBee, and machine type communication (MTC) , enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , ultra-reliable low latency communication (URLLC) , Carrier Aggregation (CA) , Dual Connectivity (DC) , and New Radio Unlicensed (NR-U) technologies.

According to example embodiments of the present disclosure, the terminal device 105 dynamically adjusts a split threshold for splitting UL data between the two

cell groups

120 and 125 based on LBT failures detected in the unlicensed spectrum.

FIG. 2 shows a flowchart of an example method 200 according to some example embodiments of the present disclosure. The method 200 can be implemented by the terminal device 105 as shown in FIG. 1. For the purpose of discussion, the method 200 will be described with reference to FIG. 1.

At block 205, the terminal device 105 detects a number of LBT failures for UL transmission in the

cell group

120 or 125 over unlicensed spectrum. In some example embodiments, the LBT failures may be detected within a time period. The time period may be configured at a network side or specified or defined in the 3GPP specifications. The LBT failures may or may not be continuous. For example, the terminal device 105 may detect the continuous LBT failures for the UL transmission in the

cell group

120 or 125 within a time period.

In some example embodiments, the LBT failures may be detected for all the UL transmission in one of the

cell groups

120 and 125. In some other example embodiments, the detection of the LBT failures may be directed to a subset or part of the UL transmission in one of the

cell groups

120 and 125 over the unlicensed spectrum. For example, the terminal device 105 may detect the LBT failures in a set of carriers or channels associated with a split threshold to be adjusted. The carriers to be detected may be the carriers to which a logical channel (LCH) corresponding to Data Radio Bearer (DRB) with the split threshold to be adjusted is mapped.

After the number of LBT failures are detected, at block 210, the terminal device 105 adjusts a split threshold for splitting UL data between the two

cell groups

120 and 125. For example, a part of the uplink data to be routed to the one of the

cell groups

120 and 125 in which the LBT failures are detected may be reduced, thereby reducing the delays and improving the throughput.

In some example embodiments, the split threshold may be used to control how much data may be split from a primary or default path to a secondary path in the two cell groups. In this example, the adjustment may be related to which cell group is primary. For example, if the cell group in which the LBT failures are detected is primary, the split threshold may be decreased. Accordingly, more UL data may be split to the primary cell group, thereby reducing the impact of the LBT failures on the data transmission, such as the increase of delays and the degradation of the throughput. If the cell group is secondary, the split threshold may be increased to allow more UL data to be routed to the other cell group.

Table 2 shows example adjustment of the split threshold in the following four example scenarios.

Table 2

As shown in Table 2, if ul-DataSplitDRB-ViaSCG is true, which means that SCG is primary, and SCG operates in the unlicensed spectrum, the LBT failures in SCG will trigger the split threshold to be automatically reduced. If ul-DataSplitDRB-ViaSCG is false, which means that SCG is non-primary and MCG is primary, and SCG operates on the unlicensed spectrum, the LBT failures in SCG will trigger the threshold to be automatically increased. If ul-DataSplitDRB-ViaSCG is true and MCG operates on the unlicensed spectrum, the LBT failures in MCG will trigger the threshold to be automatically increased. If ul-DataSplitDRB-ViaSCG is false and MCG operates on the unlicensed spectrum, the LBT failures in MCG will trigger the threshold to be automatically reduced.

If the two

cell groups

120 and 125 both operate in the unlicensed spectrum, the increased LBT failures on a primary (or default) path in the primary cell group of the

cell groups

120 and 125 will trigger the threshold to be reduced. The increased LBT failures on a secondary path in the secondary cell group of the

cell groups

120 and 125 will trigger the threshold to be increased.

In some example embodiments, the split threshold may be adjusted based on at least one step size. As an example, the step size may rely on specified values in RRC signaling from the network device 110 or 115. The values as defined in 3GPP TS 38.331 for the split threshold are as follows:

ul-DataSplitThreshold

This parameter is specified in TS 38.323. Value b0 corresponds to 0 bytes, value bl00 corresponds to 100 bytes, value b200 corresponds to 200 bytes, and so on. The network sets this parameter (or field) to ′infinity′ for UEs not supporting splitDRB-withUL-Both-MCG-SCG. If the field is absent when the split bearer is configured for the radio bearer first time, then the default value infinity is applied.

The step size used in the adjustment of the split threshold may be selected from the specified list of values as shown above. For example, if the split threshold is to be increased, the available higher value next to the current value may be selected. If the threshold is to be decreased, the next available lower value may be selected. Further, the split threshold may be adjusted (increased or decreased) in the available step size.

As another example, the

network device

110 or 115 or another network entity or functionality may configure some other step sizes for the adjustment. These step sizes may be configured in the number of bits or bytes. In some example embodiments, the configured step sizes may comprise an increase step size to increase the threshold and a decrease step size to decrease the threshold. The increase and decrease step sizes may be different.

In some example embodiments, the adjustment of the split threshold may be limited within a predefined range. For example, the limits for both the increasing and decreasing of the split threshold may be configured, which will be referred to as an upper limit and a lower limit, respectively. The upper and lower limits could be represented in bits or bytes. Alternatively, the upper and lower limits may rely on the specifed maximum and minimum values for the split threshold in the RRC signaling as specified or defined in the 3GPP specifications (for example, 3GPP TS 38.331) .

If the upper limit is reached, the split threshold may be inhibited from the adjustment to any higher value. In this case, some of the data may still be possibly transmitted via the secondary path in the secondary cell group. Alternatively, the terminal device 105 may be forced to transmit the UL data in the primary cell group of the

cell groups

120 and 125 to force the UL data to be routed only to the primary (or default) path in the primary cell group. This could be beneficial in NR where pre-processing of data to Radio Link Control (RLC) entities is allowed by a PDCP entity. If the secondary cell group experiences continuous LBT failures, it may be better to provide less data to that cell group as a PDCP Protocol Data Unit (PDU) in that cell group may stall a reception window at a receiving side for possibly long time.

If the lower limit is reached, the split threshold may be inhibited from the adjustment to any lower value. The data may be transmitted via one or two of the primary and secondary paths in the

cell groups

120 and 125 depending on the comparison of the data amount and the threshold. In some example embodiments, in this case, the terminal device 105 may autonomously trigger switching of a primary cell group and a secondary cell group of the two

cell groups

120 and 125. After the switching, the split threshold could either remain in the limit value or be reset to a predefined value such as an original value before the adjustment is performed.

In some example embodiments, the adjustment of the split threshold may be ceased if LBT failures no longer occur. In this case, the split threshold may be reset to the predefined value or the original value. For example, if one or more LBT successes are detected in the cell group in which the LBT failures occurred, the terminal device 105 may reset the split threshold to the predefined value.

In some example embodiments, the detection of no more LBT failures may be based on a counter. For example, if the number of continuous LBT failures are detected in one of the

cell groups

120 and 125, the terminal device 105 may trigger or enable a counter. Once a LBT success is detected in that cell group, the counter may be stopped or disabled. The terminal device 105 may determine that LBT failures no longer occur in that cell group.

In some example embodiments, after the threshold is adjusted, the terminal device 105 may send a buffer status report (BSR) based on the adjusted split threshold. For example, upon arrival of data to be transmitted, the terminal device 105 may determine one or two of the

cell groups

120 and 125 will be used for transmitting the data based on comparison of the amount of data and the adjusted threshold. Then, the terminal device 105 may send the BSR in the corresponding one or two cell groups. It may be possible that the terminal device 105 send the BSR in at least one of the cell groups periodically. As such, the network (NW) may be aware of the prevailing LBT issues. Hence, the possibilities may be enhanced for the NW to trigger any required reconfigurations.

FIG. 3 is a simplified block diagram of a device 300 that is suitable for implementing example embodiments of the present disclosure. The device 300 can be implemented at or as a part of the terminal device 105 or the terminal device 105 as shown in FIG. 1.

As shown, the device 300 includes a processor 310, a memory 320 coupled to the processor 310, a communication module 330 coupled to the processor 310, and a communication interface (not shown) coupled to the communication module 330. The memory 320 stores at least a program 340. The communication module 330 is for bidirectional communications, for example, via multiple antennas. The communication interface may represent any interface that is necessary for communication.

The program 340 is assumed to include program instructions that, when executed by the associated processor 310, enable the device 300 to operate in accordance with the example embodiments of the present disclosure, as discussed herein with reference to FIGS. 1 and 2. The example embodiments herein may be implemented by computer software executable by the processor 310 of the device 300, or by hardware, or by a combination of software and hardware. The processor 310 may be configured to implement various example embodiments of the present disclosure.

The memory 320 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 320 is shown in the device 300, there may be several physically distinct memory modules in the device 300. The processor 310 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 300 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

When the device 300 acts as the terminal device 105 or a part of the terminal device 105, the processor 310 and the communication module 330 may cooperate to implement the method 200 as described above with reference to FIG. 2.

All operations and features as described above with reference to FIGS. 1 and 2 are likewise applicable to the device 300 and have similar effects. For the purpose of simplification, the details will be omitted.

Generally, various example embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of example embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 200 as described above with reference to FIG. 2. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various example embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, a computer readable medium and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , Digital Versatile Disc (DVD) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular example embodiments. Certain features that are described in the context of separate example embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple example embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Various example embodiments of the techniques have been described. In addition to or as an alternative to the above, the following examples are described. The features described in any of the following examples may be utilized with any of the other examples described herein.

In some aspects, a device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the device in dual-connectivity with two cell groups to: detect a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum; and in response to the detection of the number of listen-before-talk failures, adjust a split threshold for splitting uplink data between the two cell groups.

In some example embodiments, the device is caused to adjust the split threshold by: determining whether the one of the two cell groups is primary; and in response to determining that the one of the two cell groups is primary, decreasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, the device is further caused to adjust the split threshold by: in response to determining that the one of the two cell groups is non-primary, increasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, the device is caused to adjust the split threshold by: adjusting the split threshold based on at least one step size.

In some example embodiments, the at least one step size comprises an increase step size and a decrease step size different from the increase step size.

In some example embodiments, the at least one step size comprises a predefined set of step sizes, and the device is caused to adjust the split threshold by: selecting an available step size from the predefined set of step sizes; and adjusting the split threshold in the available step size.

In some example embodiments, the device is caused to adjust the split threshold by: adjusting the split threshold within a predefined range.

In some example embodiments, the predefined range comprises an upper limit, and the device is further caused to: in response to the split threshold reaching the upper limit, only transmit the uplink data in a primary cell group of the two cell groups.

In some example embodiments, the predefined range comprises a lower limit, and the device is further caused to: in response to the split threshold reaching the lower limit, trigger switching of a primary cell group and a secondary cell group of the two cell groups.

In some example embodiments, the device is further caused to: reset the split threshold to a predefined value upon the switching.

In some example embodiments, the device is caused to detect the number of listen-before-talk failures by: detecting the number of listen-before-talk failures for the uplink transmission within a time period.

In some example embodiments, the uplink transmission comprises uplink transmission on a set of carriers associated with the split threshold over the unlicensed spectrum, and the device is caused to detect the number of listen-before-talk failures by: detecting the number of listen-before-talk failures for the uplink transmission on the set of carriers.

In some example embodiments, the device is further caused to: reset the split threshold to a predefined value in response to detecting at least one listen-before-talk success for the uplink transmission in the one of the two cell groups over the unlicensed spectrum.

In some example embodiments, the device is further caused to: send a buffer status report in at least one of the two cell groups based on the adjusted split threshold.

In some aspects, a method comprises: detecting, by a terminal device in dual-connectivity with two cell groups, a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum; and in response to the detection of the number of listen-before-talk failures, adjusting a split threshold for splitting uplink data between the two cell groups.

In some example embodiments, adjusting the split threshold comprises: determining whether the one of the two cell groups is primary; and in response to determining that the one of the two cell groups is primary, decreasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, adjusting the split threshold further comprises: in response to determining that the one of the two cell groups is non-primary, increasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, adjusting the split threshold comprises: adjusting the split threshold based on at least one step size.

In some example embodiments, the at least one step size comprises a predefined set of step sizes, and adjusting the split threshold comprises: selecting an available step size from the predefined set of step sizes; and adjusting the split threshold in the available step size.

In some example embodiments, adjusting the split threshold comprises: adjusting the split threshold within a predefined range.

In some example embodiments, the predefined range comprises an upper limit, and the method further comprises: in response to the split threshold reaching the upper limit, transmitting the uplink data only in a primary cell group of the two cell groups.

In some example embodiments, the predefined range comprises a lower limit, and the method further comprises: in response to the split threshold reaching the lower limit, triggering switching of a primary cell group and a secondary cell group of the two cell groups.

In some example embodiments, the method further comprises: resetting the split threshold to a predefined value upon the switching.

In some example embodiments, detecting the number of listen-before-talk failures comprises: detecting the number of listen-before-talk failures for the uplink transmission within a time period.

In some example embodiments, the uplink transmission comprises uplink transmission on a set of carriers associated with the split threshold over the unlicensed spectrum, and detecting the number of listen-before-talk failures comprises: detecting the number of listen-before-talk failures for the uplink transmission on the set of carriers.

In some example embodiments, the method further comprises: resetting the split threshold to a predefined value in response to detecting at least one listen-before-talk success for the uplink transmission in the one of the two cell groups over the unlicensed spectrum.

In some example embodiments, the method further comprises: sending a buffer status report in at least one of the two cell groups based on the adjusted split threshold.

In some aspects, an apparatus comprises: means for detecting, by a terminal device in dual-connectivity with two cell groups, a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum; and means for in response to the detection of the number of listen-before-talk failures, adjusting a split threshold for splitting uplink data between the two cell groups.

In some example embodiments, the means for adjusting the split threshold comprises: means for determining whether the one of the two cell groups is primary; and means for in response to determining that the one of the two cell groups is primary, decreasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, the means for adjusting the split threshold further comprises: means for in response to determining that the one of the two cell groups is non-primary, increasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.

In some example embodiments, the means for adjusting the split threshold comprises: means for adjusting the split threshold based on at least one step size.

In some example embodiments, the at least one step size comprises a predefined set of step sizes, and the means for adjusting the split threshold comprises: means for selecting an available step size from the predefined set of step sizes; and means for adjusting the split threshold in the available step size.

In some example embodiments, the means for adjusting the split threshold comprises: means for adjusting the split threshold within a predefined range.

In some example embodiments, the predefined range comprises an upper limit, and the apparatus further comprises: means for in response to the split threshold reaching the upper limit, transmitting the uplink data only in a primary cell group of the two cell groups.

In some example embodiments, the predefined range comprises a lower limit, and the apparatus further comprises: means for in response to the split threshold reaching the lower limit, triggering switching of a primary cell group and a secondary cell group of the two cell groups.

In some example embodiments, the apparatus further comprises: means for resetting the split threshold to a predefined value upon the switching.

In some example embodiments, the means for detecting the number of listen-before-talk failures comprises: means for detecting the number of listen-before-talk failures for the uplink transmission within a time period.

In some example embodiments, the uplink transmission comprises uplink transmission on a set of carriers associated with the split threshold over the unlicensed spectrum, and the means for detecting the number of listen-before-talk failures comprises: means for detecting the number of listen-before-talk failures for the uplink transmission on the set of carriers.

In some example embodiments, the apparatus further comprises: means for resetting the split threshold to a predefined value in response to detecting at least one listen-before-talk success for the uplink transmission in the one of the two cell groups over the unlicensed spectrum.

In some example embodiments, the apparatus further comprises: means for sending a buffer status report in at least one of the two cell groups based on the adjusted split threshold.

In some aspects, a computer readable storage medium comprises program instructions stored thereon, the instructions, when executed by a processor of a device, causing the device to perform the method according to some example embodiments of the present disclosure.

Claims

A device comprising:

at least one processor； and

at least one memory including computer program code；

the at least one memory and the computer program code configured to, with the at least one processor, cause the device in dual-connectivity with two cell groups to:

detect a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum； and

in response to the detection of the number of listen-before-talk failures, adjust a split threshold for splitting uplink data between the two cell groups.
The device of claim 1, wherein the device is caused to adjust the split threshold by:

determining whether the one of the two cell groups is primary； and

in response to determining that the one of the two cell groups is primary, decreasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.
The device of claim 2, wherein the device is further caused to adjust the split threshold by:

in response to determining that the one of the two cell groups is non-primary, increasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.
The device of claim 1, wherein the device is caused to adjust the split threshold by:

adjusting the split threshold based on at least one step size.
The device of claim 4, wherein the at least one step size comprises an increase step size and a decrease step size different from the increase step size.
The device of claim 4, wherein the at least one step size comprises a predefined set of step sizes, and the device is caused to adjust the split threshold by:

selecting an available step size from the predefined set of step sizes； and

adjusting the split threshold in the available step size.
The device of claim 1, wherein the device is caused to adjust the split threshold by:

adjusting the split threshold within a predefined range.
The device of claim 7, wherein the predefined range comprises an upper limit, and the device is further caused to:

in response to the split threshold reaching the upper limit, transmit the uplink data only in a primary cell group of the two cell groups.
The device of claim 7, wherein the predefined range comprises a lower limit, and the device is further caused to:

in response to the split threshold reaching the lower limit, trigger switching of a primary cell group and a secondary cell group of the two cell groups.
The device of claim 9, wherein the device is further caused to:

reset the split threshold to a predefined value upon the switching.
The device of claim 1, wherein the device is caused to detect the number of listen-before-talk failures by:

detecting the number of listen-before-talk failures for the uplink transmission within a time period.
The device of claim 1, wherein the uplink transmission comprises uplink transmission on a set of carriers associated with the split threshold over the unlicensed spectrum, and the device is caused to detect the number of listen-before-talk failures by:

detecting the number of listen-before-talk failures for the uplink transmission on the set of carriers.
The device of claim 1, wherein the device is further caused to:

reset the split threshold to a predefined value in response to detecting at least one listen-before-talk success for the uplink transmission in the one of the two cell groups over the unlicensed spectrum.
The device of claim 1, wherein the device is further caused to:

send a buffer status report in at least one of the two cell groups based on the adjusted split threshold.
A method comprising:

detecting, by a terminal device in dual-connectivity with two cell groups, a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum； and

in response to the detection of the number of listen-before-talk failures, adjusting a split threshold for splitting uplink data between the two cell groups.
The method of claim 15, wherein adjusting the split threshold comprises:

determining whether the one of the two cell groups is primary； and

in response to determining that the one of the two cell groups is primary, decreasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.
The method of claim 16, wherein adjusting the split threshold further comprises:

in response to determining that the one of the two cell groups is non-primary, increasing the split threshold to reduce a part of the uplink data to be routed to the one of the two cell groups.
The method of claim 15, wherein adjusting the split threshold comprises:

adjusting the split threshold based on at least one step size.
The method of claim 18, wherein the at least one step size comprises an increase step size and a decrease step size different from the increase step size.
The method of claim 18, wherein the at least one step size comprises a predefined set of step sizes, and adjusting the split threshold comprises:

selecting an available step size from the predefined set of step sizes； and

adjusting the split threshold in the available step size.
The method of claim 15, wherein adjusting the split threshold comprises:

adjusting the split threshold within a predefined range.
The method of claim 21, wherein the predefined range comprises an upper limit, and the method further comprises:

in response to the split threshold reaching the upper limit, transmitting the uplink data only in a primary cell group of the two cell groups.
The method of claim 21, wherein the predefined range comprises a lower limit, and the method further comprises:

in response to the split threshold reaching the lower limit, triggering switching of a primary cell group and a secondary cell group of the two cell groups.
The method of claim 23, further comprising:

resetting the split threshold to a predefined value upon the switching.
The method of claim 15, wherein detecting the number of listen-before-talk failures comprises:

detecting the number of listen-before-talk failures for the uplink transmission within a time period.
The method of claim 15, wherein the uplink transmission comprises uplink transmission on a set of carriers associated with the split threshold over the unlicensed spectrum, and detecting the number of listen-before-talk failures comprises:

detecting the number of listen-before-talk failures for the uplink transmission on the set of carriers.
The method of claim 15, further comprising:

resetting the split threshold to a predefined value in response to detecting at least one listen-before-talk success for the uplink transmission in the one of the two cell groups over the unlicensed spectrum.
The method of claim 15, further comprising:

sending a buffer status report in at least one of the two cell groups based on the adjusted split threshold.
An apparatus comprising:

means for detecting, by a terminal device in dual-connectivity with two cell groups, a number of listen-before-talk failures for uplink transmission in one of the two cell groups over unlicensed spectrum； and

means for in response to the detection of the number of listen-before-talk failures, adjusting a split threshold for splitting uplink data between the two cell groups.
A computer readable storage medium comprising program instructions stored thereon, the instructions, when executed by a processor of a device, causing the device to perform the method of any of claims 15-28.