Determination of bit rate

Abstract

Embodiments of the present disclosure relate to determination of a recommended bit rate. In one aspect, a terminal device The terminal device then receives a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device from the first network device. Based on the MAC CE, the terminal device determines a bit rate to be used.

Description

DETERMINATION OF BIT RATEFIELD

[0001] Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and a computer readable storage medium for determination of a bit rate.BACKGROUND

[0002] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of communication network.

[0003] Such communication networks operate in accordance with standards, such as those promulgated by Third Generation Partnership Project (3 GPP) or European Telecommunications Standards Institute (ETSI). Examples of such standards include the so-called 5th generation (5G) standard, 6th generation (6G) or other standards promulgated by 3 GPP.SUMMARY

[0004] In general, example embodiments of the present disclosure provide a solution for determination of a bit rate.

[0005] In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a first network device, a first recommended bit rate (RBR) of the first network device, receive, from a second network device, a second RBR of the second network device, and determine, based on the first RBR and the second RBR, a bit rate to be used.

[0006] In a second aspect, there is provided a first network device. The first network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to: transmit, to a second network device, a second query for a second recommended bit rate (RBR) of the second network device, and transmit, to a terminal device, a first RBR of a first networkdevice.

[0007] In a third aspect, there is provided a second network device. The second network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second network device at least to: receive, from a first network device, a second query for a second recommended bit rate (RBR), and transmit, to the terminal device, the second RBR of the second network device.

[0008] In a fourth aspect, there is provided a terminal device. The terminal device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device, and determine, based on the MAC CE, a bit rate to be used.

[0009] In a fifth aspect, there is provided a first network device. The first network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to: transmit, to the second network device, a first query for a recommended bit rate (RBR), receive, from a second network device, a second RBR of the second network device, determine a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and transmit, to a terminal device, the MAC CE.

[0010] In a sixth aspect, there is provided a second network device. The second network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second network device at least to: transmit, to a first network device, a second recommended bit rate (RBR) of the second network device.

[0011] In a seventh aspect, there is provided a terminal device. The terminal device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first recommended bit rate (RBR) of the first network device and the second RBR of a second network device, and determine, based on the MAC CE, a bit rate to be used.

[0012] In an eighth aspect, there is provided a first network device. The first network devicecomprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to: receive, from a second network device, a second recommended bit rate (RBR) of the second network device, determine a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and transmit, to a terminal device, the MAC CE.

[0013] In a ninth aspect, there is provided a second network device. The second network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second network device at least to: transmit, to a first network device, the second recommended bit rate (RBR) of a second network device.

[0014] In a tenth aspect, there is provided a method. The method comprises receiving, at a terminal device and from a first network device, a first recommended bit rate (RBR) of the first network device, receiving, from a second network device, a second RBR of the second network device; and determining, based on the first RBR and the second RBR, a bit rate to be used.

[0015] In an eleventh aspect, there is provided a method. The method comprises transmitting, at a first network device and to a second network device, a second query for a second RBR of the second network device, and transmitting, to a terminal device, a first RBR of a first network device.

[0016] In a twelfth aspect, there is provided a method. The method comprises receiving, at a second network device and from a first network device, a second query for a second recommended bit rate (RBR), and transmitting, to the terminal device, the second RBR of the second network device.

[0017] In a thirteenth aspect, there is provided a method. The method comprises receiving, at a terminal network device and from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device, and determining, based on the MAC CE, a bit rate to be used.

[0018] In a fourteenth aspect, there is provided a method. The method comprises transmitting, at a first network device and to the second network device, a first query for a recommended bit rate (RBR), receiving, from a second network device, a second RBR of thesecond network device, determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and transmitting, to a terminal device, the MAC CE.

[0019] In a fifteenth aspect, there is provided a method. The method comprises transmitting, at a second network device and to a first network device, a second recommended bit rate (RBR) of the second network device.

[0020] In a sixteenth aspect, there is provided a method. The method comprises receiving, at a terminal device and from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first recommended bit rate (RBR) of the first network device and the second RBR of a second network device, and determining, based on the MAC CE, a bit rate to be used.

[0021] In a seventeenth aspect, there is provided a method. The method comprises receiving, at a first network device and from a second network device, a second recommended bit rate (RBR) of the second network device, determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and transmitting, to a terminal device, the MAC CE.

[0022] In an eighteenth aspect, there is provided a method. The method comprises transmitting, at a second network device and to a first network device, the second RBR of the second network device.

[0023] In a nineteenth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a terminal device and from a first network device, a first recommended bit rate (RBR) of the first network device, means for receiving, from a second network device, a second RBR of the second network device, and means for determining, based on the first RBR and the second RBR, a bit rate to be used.

[0024] In a twentieth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a first network device and to a second network device, a second query for a second RBR of the second network device, and means for transmitting, to a terminal device, a first RBR of a first network device.

[0025] In a twenty-first aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a second network device and from a first network device, a second query for a second recommended bit rate (RBR), and means for transmitting, to a terminal device, the second RBR of the second network device.

[0026] In a twenty-second aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a terminal network device and from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device, and means for determining, based on the MAC CE, a bit rate to be used.

[0027] In a twenty-third aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a first network device and to the second network device, a first query for a recommended bit rate (RBR), means for receiving, from a second network device, a second RBR of the second network device, means for determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and means for transmitting, to a terminal device, the MAC CE.

[0028] In a twenty-fourth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a second network device and to a first network device, a second recommended bit rate (RBR) of the second network device.

[0029] In a twenty-fifth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a terminal device and from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first recommended bit rate (RBR)and the second RBR, and means for determining, based on the MAC CE, a bit rate to be used.

[0030] In a twenty-sixth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a first network device and from a second network device, a second recommended bit rate (RBR) of the second network device, means for determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and means for transmitting, to a terminal device, the MAC CE.

[0031] In a twenty-sixth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a second network device and to a first network device, the second RBR of the second network device.

[0032] In a twenty-seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above tenth to eighteenth aspect.

[0033] In a twenty-eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to any one of the above tenth to eighteenth aspect.

[0034] In a twenty-ninth aspect, there is provided a terminal device. The terminal device comprises first receiving circuitry configured to receive, from the first network device, a first RBR of the first network device, second receiving circuitry configured to receive, from a second network device, a second RBR of the second network device, and determining circuitry configured to determine, based on the first RBR and the second RBR, a bit rate to be used.

[0035] In a thirtieth aspect, there is provided a first network device. The first network device comprises first transmitting circuitry configured to transmit, to a second network device, a second query for a second RBR of the second network device, and second transmitting circuitry configured to transmit, to a terminal device, a first RBR of a first network device.

[0036] In a thirty-first aspect, there is provided a second network device. The second network device comprises receiving circuitry configured to receive, from a first network device, a second query for a second recommended bit rate (RBR), and transmitting circuitry configured to transmit, to the terminal device, the second RBR of the second network device.

[0037] In a thirty-second aspect, there is provided a terminal device. The terminal device comprises receiving circuitry configured to receive, from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device, and determining circuitry configured to determine, based on the MAC CE, a bit rate to be used.

[0038] In a thirty-third aspect, there is provided a first network device. The first network device comprises first transmitting circuitry configured to transmit, to the second network device, a first query for a recommended bit rate (RBR), receiving circuitry configured to receive, from a second network device, a second RBR of the second network device, determining circuitry configured to determine a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and second transmitting circuitry configured to transmit, to a terminal device, the MAC CE.

[0039] In a thirty-fourth aspect, there is provided a second network device. The second network device comprises transmitting circuitry configured to transmit, to a first networkdevice, a second recommended bit rate (RBR) of the second network device.

[0040] In a thirty-fifth aspect, there is provided a terminal device. The terminal device comprises receiving circuitry configured to receive, from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first RBR of the first network device and the second RBR of a second network device, and determining circuitry configured to determine, based on the MAC CE, a bit rate to be used.

[0041] In a thirty-sixth aspect, there is provided a first network device. The first network device comprises receiving circuitry configured to receive, from a second network device, a second recommended bit rate (RBR) of the second network device, determining circuitry configured to determine a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and transmitting circuitry configured to transmit, to a terminal device, the MAC CE.

[0042] In a thirty-seventh aspect, there is provided a second network device. The second network device comprises transmitting circuitry configured to transmit, to a first network device, the second RBR of the second network device.

[0043] It is to be understood that the summary section is not intended to identify key or essential features of 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

[0044] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0045] Fig. 1 illustrates an example network environment in which example embodiments of the present disclosure may be implemented;

[0046] Fig. 2 illustrates a first example signaling chart illustrating an example process according to some embodiments of the present disclosure;

[0047] Fig. 3 illustrates an example process with separate RBR MAC CEs;

[0048] Fig. 4 illustrates another example process with separate RBR MAC CEs;

[0049] Fig. 5 illustrates a second example signaling chart illustrating an example process according to some embodiments of the present disclosure;

[0050] Fig. 6 illustrates an example format of the joint RBR MAC CE;

[0051] Fig. 7 illustrates another example format of the joint RBR MAC CE;

[0052] Fig. 8 illustrates a third example signaling chart illustrating an example process according to some embodiments of the present disclosure;

[0053] Fig. 9 illustrates an example process with the joint RBR MAC CE;

[0054] Fig. 10 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

[0055] Fig. 11 illustrates a flowchart of a method implemented at a first network device according to some example embodiments of the present disclosure;

[0056] Fig. 12 illustrates a flowchart of a method implemented at a second network device according to some example embodiments of the present disclosure;

[0057] Fig. 13 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

[0058] Fig. 14 illustrates a flowchart of a method implemented at a first network device according to some example embodiments of the present disclosure;

[0059] Fig. 15 illustrates a flowchart of a method implemented at a second network device according to some example embodiments of the present disclosure;

[0060] Fig. 16 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

[0061] Fig. 17 illustrates a flowchart of a method implemented at a first network device according to some example embodiments of the present disclosure;

[0062] Fig. 18 illustrates a flowchart of a method implemented at a second network device according to some example embodiments of the present disclosure;

[0063] Fig. 19 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

[0064] Fig. 20 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

[0065] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0066] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement example embodiments of the present disclosure, without suggesting any limitation as to the scope of the disclosure. The example embodiments of the present disclosure described herein can be implemented in various manners other than the ones described below.

[0067] 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.

[0068] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0069] It shall be understood that although the terms “first” and “second” etc. 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 termed 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.

[0070] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. 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. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0071] As used in this application, 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.

[0072] 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 server, a cellular network device, or other computing or network device.

[0073] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as long term evolution (LTE), LTE-advanced (LTE-A), wideband code division multiple access (WCDMA), high-speed packet access (HSPA), narrow band internet of things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G,2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which example embodiments of the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0074] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a new radio (NR) NB (also referred to as a gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0075] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an internet of things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0076] Fig. 1 illustrates an example network environment 100 in which exampleembodiments of the present disclosure may be implemented. The environment or communication system 100, which may be a part of a communication network, comprises terminal devices and network devices.

[0077] As illustrated in Fig. 1, the communication system 100 may comprise a terminal device 110 (hereinafter may also be referred to as user equipment 110 or UE 110), a network device 120 (hereinafter may also be referred to as first network device 120, base station 120 or gNB 120), and a network device 130 (hereinafter may also be referred to as second network device 130, base station 130 or gNB 130). The network device 120 can manage a cell 101 and the network device 130 can manage a cell 102. The terminal device 110 can communicate with the network device 120 in the coverage of the cell 101. The terminal device 110 can communicate with the network device 130 in the coverage of the cell 102. A link from the terminal device 110 or the terminal device 130 to the network device 120 is referred to as an uplink (UL), while a link from the network device 120 to the terminal device 110 or the terminal device 130 is referred to as a downlink (DL).

[0078] It is to be understood that the number of devices is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of terminal devices or network devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices or network devices may be located in the system 100.

[0079] Communications in the communication system 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiple (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0080] The evolution of extended reality (XR) applications is paving the way for dynamic codec adaptation based on available network throughput. Many XR applications already support this capability, adjusting their encoding parameters to optimize performance.

[0081] With the advent of 5GNR, specifically its enhanced support for the XR, RAN-aware XR rate control emerges as a crucial technology. This enables XR applications to dynamically adjust their codec bitrate and encoding parameters in real-time, ensuring a seamless and high-quality user experience. By monitoring network conditions, XR applications may adapt their behavior. For instance, in congested network scenarios, they can reduce the resolution or the frame rate to maintain the smooth operation.

[0082] RAN congestion awareness is a key to achieve the optimal XR performance. XR applications are highly sensitive to latency, and network congestion significantly impacts the latency and can even lead to the packet loss or delayed packet delivery. Therefore, RAN congestion information is essential for the XR rate control. By providing this information to XR applications, they may optimize their rate control mechanisms, leading to improved quality of service (QoS) and an enhanced user experience.

[0083] Since Rel-17, 3 GPP has been working on various enhancements in order for efficient support of XR applications. The revised work item description (WID) for Rel-19 XR Phase 3 contains an objective on UL congestion control, i.e., specify uplink congestion signaling. Specifying uplink congestion signaling comprises specifying in MAC layer XR rate control signalling over downlink per QoS flow / per data Radio Bearer (DRB) to enable faster source rate adaption to uplink congestion.

[0084] RAN2 has started discussion on XR rate control in the RAN2#127bis. 5G new radio (NR) dual connectivity (DC) allows a device to simultaneously connect to two different 5G NR cells, effectively combining their resources. This provides several benefits, including increased bandwidth, improved coverage, enhanced reliability, and potentially reduced latency. Overall, it includes different steps, for example, device discovery, initial connection, resource allocation and data transmission. At the device discovery, the device searches for and discovers two suitable 5G NR cells within its coverage area. At the initial connection, the device establishes an initial connection to both cells, known as the master node (MN) and secondary node (SN). At the resource allocation, the network allocates resources (e.g., bandwidth, time slots) to the device across both cells. At the data transmission, the device may then transmit and receive data using both cells simultaneously. 5G NR dual connectivityis a powerful technology that can significantly enhance the performance and capabilities of 5G networks.

[0085] A recommended bit rate procedure is specified which offers a framework for controlling the bit rates based on e.g., radio link quality. The recommended bit rate procedure is used to provide the MAC entity with information about the bit rate which the gNB recommends. The bit rate is the recommended bit rate of the physical layer. Averaging window of default value 2000 ms will apply as specified in TS 26.114

[0013] , The gNB may transmit the Recommended bit rate MAC CE to the MAC entity to indicate the recommended bit rate for the UE for a specific logical channel and a specific direction (either uplink or downlink). Upon reception of a Recommended bit rate MAC CE the MAC entity may indicate to upper layers the recommended bit rate for the indicated logical channel and direction.

[0086] The MAC entity may request the gNB to indicate the recommended bit rate for a specific logical channel and a specific direction. If the MAC entity is requested by upper layers to query the gNB for the recommended bit rate for a logical channel and for a direction (i.e. for uplink or downlink), if a Recommended bit rate query for this logical channel and this direction has not been triggered, the MAC entity may trigger a Recommended bit rate query for this logical channel, direction, and desired bit rate. If the MAC entity has UL resources allocated for new transmission, for each Recommended bit rate query that the Recommended Bit Rate procedure determines has been triggered and not cancelled: if bitRateQueryProhibitTimer for the logical channel and the direction of this Recommended bit rate query is configured, and it is not running; and if the MAC entity has UL resources allocated for new transmission and the allocated UL resources can accommodate a Recommended bit rate MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1 of TS 38.321, the MAC entity may: instruct the Multiplexing and Assembly procedure to generate the Recommended bit rate MAC CE for the logical channel and the direction of this Recommended bit rate query; start the bitRateQueryProhibitTimer for the logical channel and the direction of this Recommended bit rate query; or cancel this Recommended bit rate query.

[0087] The recommended bit rate procedure may be used to provide the MAC entity with information about the bit rate which the gNB recommends. The bit rate is the recommended bit rate of the physical layer. Averaging window of default value 2000 ms will apply as specified in TS 26.114

[0013] , The gNB may transmit the recommended bit rate MAC CE tothe MAC entity to indicate the recommended bit rate for the UE for a specific logical channel and a specific direction (either uplink or downlink). Upon reception of a recommended bit rate MAC CE the MAC entity may indicate to upper layers the recommended bit rate for the indicated logical channel and direction. In short, the UE receives the recommended bit rate MAC CE per logical channel from the gNB; the UE may request the gNB to provide the Recommended Bit Rate for a certain logical channel; and the bit rate recommended MAC CE is of 2 octets including 6 bits of logical channel identity (LCID) field, 5 bits of bit rate field, 1 bit of bit rate multiplier, and 1 bit of UL / DL field.

[0088] It was discussed how the rate control is done for the case with split bearer where the data packets from the same bearer are sent over both master cell group (MCG) and secondary cell group (SCG). In DC scenario, split bearer may be used for XR services to boost the throughput. If both master node (MN) and secondary node (SN) send MAC CEs for rate control of the same split bearer or same QoS flow(s) mapped to split bearer, some discussion might be needed on UE behavior regarding which data rate to be applied for the split bearer or DRB as indicated in the MAC CEs, e.g. whether UE follows latest MAC CE from MN or SN, or UE considers the MAC CEs jointly. It is proposed to discuss whether split bearer can be considered for rate control.

[0089] Following the latest MAC CE from either the MN or the SN won’t be effective without coordination between the MN and the SN, as the congestion in the MN and the SN would occur independent of each other while it is unclear how the UE consider both MAC CEs jointly.

[0090] In case of split transmission via the MCG and the SCG, the UE may be provided with recommended bit rate 1 of a QoS flow / DRB from cell 1 of the MCG and recommended bit rate 2 of the same QoS flow / DRB from cell 2 of the SCG. It is proposed that the recommended bit rate for a DRB or QoS flow may be applied to the cell where the MAC CE is received. Additionally, in case of duplicate transmission, it was proposed to use the minimum bit rate values among the bit rate values received from the MN and the SN.

[0091] The data of a logical channel (LCH) belongs to a specific cell, whereas the data of a DRB or QoS flow may be transmitted over more than one cell (or LCH) during PDCP duplication or split transmission. Due to varying congestion situations in different cells, UE may receive the recommended bit rate for the same DRB or QoS flow from different cells (e.g., during CA / DC). In this case, how to apply the indicated recommended bit rate is to bediscussed.

[0092] For example, UE may be provided with recommended bit rate 1 of a QoS flow / DRB from cell 1 and recommended bit rate 2 of the same QoS flow / DRB from cell 2. For PDCP duplication, the UE may not be expected to go beyond the recommended bit rate of min (recommended bit rate 1, recommended bit rate 2) for the DRB or the QoS flow. For split transmission, the recommended bit rate for a DRB or QoS flow may be applied to the cell where the MAC CE is received. UE needs to guarantee that the bit rate of the DRB or QoS flow in each cell will not go beyond the recommended bit rate of the corresponding cell.

[0093] The same issue arises in scenarios of per DRB bit rate recommendation with a 1:N mapping between DRBs and LCHs, but the solution is analogous, so redundancy is avoided by not repeating it.

[0094] Due to varying congestion situations in different cells, UE may receive the recommended bit rate for a DRB or QoS flow from different cells. It is proposed to discuss how to apply the indicated recommended bit rate of a DRB or QoS flow when more than one indication is received from different cells (e.g., during CA / DC).

[0095] For the split case, using the minimum value by the UE itself may confuse the network scheduling as the gNB does not know which value the UE applies, and which value is transmitted by the other gNB. For the duplication case, it won’t make sense to apply the rate control at the cell or group of cell level as the application doesn’t know the cell through which the packet is to be sent until the packets are available at layer 2 (e.g., packet data convergence protocol (PDCP) or radio link control (RLC)) and the grant is received.

[0096] All the details of how to handle split bear in case with recommended bit rate MAC CE are missing, especially considering UE behaviour and also whether the recommended bit rate MAC CE may be sent independently from all serving cells of the UE which results in double overhead. It is to be addressed that is it even better if the MAC CE is sent only over PCell from MN, considering the main purpose of the MAC CE is used to inform UE the recommended bit rate which can be further used by the UE to adjust the application bit rate.

[0097] According to some embodiments of the present disclosure, a solution is provided for determination of a bit rate, for example, to enable UL rate control for XR with dual connectivity. In one aspect of this solution, a terminal device receives a first RBR of the first network device from the first network device and receives a second RBR of the second network device from the second network device. Based on the first RBR and the second RBR,the terminal device determines a bit rate to be used. In this way, the bit rate to be used may be determined. Therefore, the communication efficiency is improved. Principles and implementations of embodiments of the present disclosure will be described in detail below with reference to Figs. 2-20.

[0098] Fig. 2 illustrates a first example signaling chart illustrating an example process 200 according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve the terminal device 110, the first network device 120 and the second network device 130. It would be appreciated that although the process 200 has been described in relation to the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios with similar issues. In some embodiments, the first network device 120 may be a master node of the terminal device, and the second network device 130 may be a secondary node of the terminal device. Alternatively, the second network device 130 may be a master node (MN) of the terminal device, and the first network device 120 may be a secondary node (SN) of the terminal device.

[0099] In the process 200, the first network device 120 transmits 225 a second query for a second RBR of the second network device 230 to the second network device 130. In some embodiments, the second RBR 230 may be transmitted via a second MAC CE or other signalling over Xn interface for example. In addition, the second RBR 230 may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof.

[0100] In some embodiments, the terminal device 110 may further transmit 210 a first query for a RBR 215 to the first network device 120. In other words, triggered by the first query from the terminal device 110, the first network device 120 may request the second network device 130 to provide the RBR for a certain LCH / LCG / DRB / QoS flow of the terminal device 110.

[0101] In addition, the first RBR 230 may be for a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), a quality of service (QoS) flow, or any combination thereof.

[0102] For example, the terminal device 110 may request either the MN or the SN to provide the RBR for a certain LCH or LCG or DRB or QoS flow by the first query 215.

[0103] In some embodiments, the terminal device 110 may further obtain configuration information associated with the first RBR and a second RBR of the second network device130. Alternatively or additionally, the configuration information may indicate that the first RBR and the second RBR are to be received from the first network device 120 and the second network device 130 respectively. In addition, the configuration information may indicate that the first RBR and the second RBR are triggered by at most one query for the RBR from the terminal device. In other words, the terminal device may transmit one query to trigger the first RBR and the second RBR.

[0104] In an example, during the DC configuration phase, the MN (i.e., the first network device 120) may configure the terminal device 110 that separate RBR MAC CEs may be sent via the MN and the SN(i.e., the second network device 130).

[0105] In some embodiments, the configuration information may be received from the first network device 120. Correspondingly, the first network device 120 may transmit the configuration information associated with the first RBR and the second RBR to the terminal device 110.

[0106] In some alternative embodiments, the configuration information may be predefined. For instance, the configuration information may be specified in 3GPP specification.

[0107] Continuing with reference to Fig. 2, the first network device 120 transmits 240 a first RBR of the first network device 245 to the terminal device 110. Correspondingly, the terminal device 110 receives 250 the first RBR of the first network device 245 from the first network device 120. In some embodiments, the first RBR 245 may be received via a first MAC CE.

[0108] It is to be understood that the sequence of process in FIG. 2 is only for the purpose of illustration without suggesting any limitations. The first network device 120 may transmit the second query 230 before transmitting the first RBR 245 or after transmitting the first RBR 245.

[0109] After receiving 235 the second query for a second RBR of the second network device 230 from the first network device 120, the second network device 130 transmits 255 the second RBR of the second network device 260 to the terminal device 110. Correspondingly, the terminal device 110 receives 265 the second RBR of the second network device 260 from the second network device 130.

[0110] Based on the first RBR and the second RBR, the terminal device 110 determines 270 a bit rate to be used. In addition, the bit rate to be used may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof. In some embodiments, the terminal device 110 maydetermine the bit rate based on a sum of the first RBR and the second RBR.

[0111] Alternatively or additionally, based on the bit rate, the terminal device 110 may further adjust data splitting toward the first network device 120 and the second network device 130, an application bit rate of the terminal device 110, or both.

[0112] For example, the terminal device 110 receives two independent RBRs from the MN and the SN and the recommended bit rate value in the RBR MAC CEs cannot be directly used by the terminal device 110 to adjust bit rate at application layer. Instead, the terminal device 110 may combine or sum the received recommended bit rates and then the summed value may be used by the application layer to adjust bit rate.

[0113] In some embodiments, the terminal device 110 may further receive a third RBR from one of the first network device 120 or the second network device 130. Based on the third RBR and a fourth RBR from another of the first network device 120 or the second network device 130, the terminal device 110 may determine an updated bit rate to be used. In some embodiments, the third RBR may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof. Alternatively or additionally, the third RBR may be transmitted via a third MAC CE. In addition, the updated bit rate to be used may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof. Additionally, the fourth RBR may be transmitted via a fourth MAC CE. In addition, the fourth RBR may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof. It is to be understood that the fourth RBR is not the first RBR or the second RBR received before.

[0114] In some embodiments, the first network device 120 may transmit the third RBR to the terminal device 110. Alternatively, the second network device 130 may transmit the third RBR to the terminal device 110. The third RBR may be used for updating the RBR for the terminal device 110, and the third RBR may be triggered by the change of a congestion state.

[0115] In addition, the terminal device 110 may further transmit a query for updating an RBR to the another of the first network device 120 or the second network device 130. The terminal device 110 may then receive the fourth RBR from the another of the first network device 120 or the second network device 130.

[0116] In some embodiments, the first network device 120 may receive the query for updating the RBR from the terminal device 110. Alternatively, the second network device 130 may receive the query for updating the RBR from the terminal device 110.

[0117] For the separate MAC CEs from MN and SN, in order to avoid the terminal device110 applying the inaccurate RBR to adjust the application bit rate, the terminal device 110 may apply the MAC CEs when the terminal device 110 receives such indication from both the MN and the SN.

[0118] In an example, with separate MAC CEs from the MN and the SN, it is also possible that only one of the MN or the SN sends the updated MAC CE. In this case, the terminal device 110 may request RBR information from another node or the terminal device 110 may rely on the available information to derive the combined RBR. For example, in case only the SN sending the MAC CE comprising the RBR, then the terminal device 110 may get combined RBR based on the new MAC CE from SN and already available RBR from MN.

[0119] Fig. 3 illustrates an example process with separate RBR MAC CEs. The process 300 may involve a UE 301, a MN 302 and a SN 303. It is understood that the process 300 can be considered as a more specific example of process 200. Thus, the UE 301 of Fig. 3 may represent for example the terminal device 110 of Fig. 2, the MN 302 of Fig. 3 may represent for example the first network device 120 of Fig. 2, and the SN 303 of Fig. 3 may represent for example the second network device 130 of Fig. 2.

[0120] In the process 300, at 310, the MN 302 configures the UE 301 for usage of separate RBR MAC CE. Alternatively, the usage of the separate RBR MAC CE may also be specified in 3 GPP specifications.

[0121] At 315, the UE 301 transmits a recommended bit rate query to the MN 302. At 320, the MN 302 transmits the recommended bit rate query for the UE 301 to the SN 303. At 325, the MN 302 transmits a recommended bit rate MAC CE to the UE 301. At 330, the SN 303 transmits a recommended bit rate MAC CE to the UE 301.

[0122] At 335, the UE 301 determines the recommended bit rate by combining RBRs from both the MN 302 and the SN 303, and adjusts data splitting towards the MN 302 and the SN 303. The UE 301 and / or the application further determines suitable bit rate based on the determined recommended bit rate.

[0123] Fig. 4 illustrates another example process with separate RBR MAC CEs. The process 400 may involve a UE 401, a MN 402 and a SN 403. It is understood that the process 400 can be considered as a more extension example of process 200. Thus, the UE 401 of Fig.4 may represent for example the terminal device 110 of Fig. 2, the MN 402 of Fig. 4 may represent for example the first network device 120 of Fig. 2, and the SN 403 of Fig. 4 may represent for example the second network device 130 of Fig. 2.

[0124] In the process 400, at 410, the MN 402 configures the UE 401 for usage of separate RBR MAC CE. Alternatively, the usage of the separate RBR MAC CE may also be specified in 3 GPP specifications.

[0125] At 415, the UE 401 may transmit a recommended bit rate query to the MN 402. At 420, the UE 401 may transmit a recommended bit rate query to the SN 403.

[0126] At 425, the MN 402 transmits a recommended bit rate MAC CE to the UE 401. At 430, the SN 403 transmits a recommended bit rate MAC CE to the UE 401. The recommended bit rate MAC CE may be triggered by the recommended bit rate query from the UE 401 or other conditions from network side (e.g. MN 402 and / or SN 403 detecting UL congestion state change without the recommended bit rate query from the UE 401).

[0127] At 435, the UE 401 determines the recommended bit rate by combining RBRs from both the MN 402 and the SN 403, and adjusts data splitting towards the MN 402 and the SN 403. The UE 401 and / or the application further determines suitable bit rate based on the determined recommended bit rate.

[0128] Fig. 5 illustrates a second example signaling chart illustrating an example process 500 according to some embodiments of the present disclosure. For the purpose of discussion, the process 500 will be described with reference to Fig. 1. The process 500 may involve the terminal device 110, the first network device 120 and the second network device 130. It would be appreciated that although the process 500 has been described in relation to the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios with similar issues. In some embodiments, the first network device 120 may be a master node of the terminal device, and the second network device 130 may be a secondary node of the terminal device. Alternatively, the second network device 130 may be a master node of the terminal device, and the first network device 120 may be a secondary node of the terminal device.

[0129] In the process 500, the first network device 120 transmits 510 a first query for an RBR 515 to the second network device 130. On the other side of the communication, the second network device 130 may receive 520 the first query for an RBR 515 from the first network device 120.

[0130] Additionally, the first network device 120 may transmit 510 the first query based on receiving the second query from the terminal device, or determining a change of a congestion state at the first network device. In some examples, the change of a congestion state maycomprise or correspond to a congestion state that is occurring or ongoing, a congestion state that is diminishing, decreasing, or going away, or some other congestion situation change. In addition, the congestion state may comprise or correspond to a state of congestion in the uplink.

[0131] In some embodiments, the terminal device 110 may further transmit the second query for an RBR to the first network device 120, and a MAC CE comprising the first RBR and the second RBR (i.e., joint RBR MAC CE) is in response to the query. Correspondingly, the first network device 120 may receive the second query for an RBR from the terminal device 110.

[0132] In an example, triggered by the first query or other conditions from network side (e.g. the first network device 120 and / or the second network device 130 detecting UL congestion state change without the first query from the terminal device 110), the first network device 120 requests the second network device 130 to provide recommended bit rate for a certain LCH / LCG / DRB / QoS flow of the terminal device 110.

[0133] It is a logic assumption that the terminal device 110 sending a query message to the MN only, however, example embodiments of the present disclosure also covered the scenario that the terminal device 110 sends the query message to the SN. In this case, the SN may send recommended bit rate to the MN without the request from the MN.

[0134] Alternatively or additionally, the terminal device 110 may further obtain configuration information associated with the MAC CE comprising the first RBR and the second RBR.

[0135] In some embodiments, the configuration information may be received from the first network device 120. Correspondingly, the first network device 120 may transmit the configuration information associated with the MAC CE to the terminal device 110. In some alternative embodiments, the configuration information may be predefined.

[0136] In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device 120. For example, during the DC configuration phase, the MN may configure UE that the joint RBR MAC CE will be sent via the MN. As an alternative, the joint RBR MAC CE will be sent from the SN depending on the e.g. load status, channel conditions etc. and the SN taking the role of the MN.

[0137] In some alternative embodiments, the MAC CE is a first MAC CE comprising the first RBR and the second RBR, the configuration information may indicate that the first MACCE is to be received from the first network device 120 and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device 130. For example, the MN may configure the UE that the joint RBR MAC CE will be sent from both the MN and the SN for the purpose of increased reliability.

[0138] Continuing with reference to Fig. 5, the second network device 130 transmits 525 a second RBR of the second network device 530 to the first network device 120. In some embodiments, the second RBR 530 is in response to a query from the first network device 120 or is triggered by a change of a congestion state in the second network device 130.

[0139] After receiving 535, the second RBR 530 of the second network device from the second network device 130, the first network device 120 determines 540 a MAC CE comprising a first RBR of the first network device and the second RBR of the second network device. In some embodiments, the first RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow. In addition, the second RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow.

[0140] In an example, based on the information received from the SN and the MN’s own estimation of recommended bit rate for a certain LCH / LCG / DRB / QoS flow, the MN generates the RBR MAC CE and sends it to the UE.

[0141] In some embodiments, the MAC CE may comprise a first field indicating the first RBR and a second field indicating the second RBR. In addition, the MAC CE can include a third field, which indicates a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID), a quality of service (QoS) flow ID (QFI) associated with the first network device, or any combination thereof.

[0142] Fig. 6 illustrates an example format of joint RBR MAC CE. As shown in Fig. 6, “Bit rate l” is used to indicate the recommended bit rate for MN, XI is used to indicate the multiplier to be applied for MN, and “Bit rate_2” for recommended bit rate for the SN, X2 is used to indicate the multiplier to be applied for SN. LCID may take the LCID from the MN side. Since the terminal device 110 has fully knowledge about DRB-LCH mapping, it is sufficient to include a single LCID field.

[0143] Fig. 7 illustrates another example format of joint RBR MAC CE. The joint RBR MAC CE with one single recommend bit rate formulated is shown in Fig. 7, one single information element (IE) is used to indicate the combined recommended bit rate from both the MN and the SN.

[0144] Reference is made back to Fig. 5, the first network device 120 transmits 545 the MAC CE 550 to the terminal device 110. On the other side of the communication, the terminal device 110 may receive 555 the MAC CE comprising the first RBR of the first network device and the second RBR of the second network device 550 from the first network device 120. For instance, the terminal device 110 receives the RBR MAC CE from the MN for example a PCell.

[0145] In some embodiments, the second network device 130 may further transmit the MAC CE comprising the first RBR of the first network device and the second RBR to the terminal device 110.

[0146] For example, the configuration information indicates that the first MAC CE is to be received from the first network device 120 and the second MAC CE is to be received from the second network device 130. The second network device 130 may obtain the MAC CE comprising the first RBR and the second RBR from the first network device 120, then transmit the MAC CE comprising the first RBR and the second RBR to the terminal device 110.

[0147] Continuing with reference to Fig. 5, the terminal device 110 determines 560 a bit rate to be used based on the MAC CE. In addition, the bit rate to be used may be for a LCH, a LCG, a DRB, a QoS flow, or any combination thereof.

[0148] In some embodiments, based on the MAC CE, the terminal device 110 may determine the first RBR of the first network device 120 and the second RBR of the second network device 130. Based on the first RBR and the second RBR, the terminal device 110 may determine the bit rate. Additionally, the terminal device 110 may determine the bit rate based on a sum of the first RBR and the second RBR.

[0149] Alternatively or additionally, based on the bit rate, the terminal device 110 may further adjust data splitting toward the first network device 120 and the second network device 130, an application bit rate of the terminal device 110, or both.

[0150] With the joint RBR MAC CE, the terminal device 110 may know that the received recommended bit rate(s) in the joint RBR MAC CE covers the recommended bit rates from both the MN and the SN. Then the received recommended bit rate(s) may be directly used by the terminal device 110 to adjust the bit rate at application layer.

[0151] Depending on the joint RBR MAC CE design, in case the recommended bit rates for MN and SN are separately indicated in different fields of the same RBR MAC CE asshown in Fig. 6, then the terminal device 110 may use the combined recommended bit rate to adjust the bit rate at application layer.

[0152] In some embodiments, the terminal device 110 may further receive a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device from the first network device 120. Based on the third MAC CE, the terminal device 110 may determine an updated bit rate to be used. In some embodiments, the third RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow. In addition, the updated bit rate to be used may be for one or more of a LCH, a LCG, a DRB, or a QoS flow. The third RBR may be used for updating the RBR for the terminal device 110.

[0153] Additionally, the fourth RBR may be transmitted via a fourth MAC CE. In addition, the fourth RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow.

[0154] In some embodiments, if at least one change of at least one congestion state in at least one of the first network device or the second network device, the first network device 120 may transmit the third MAC CE comprising a third RBR of the first network device and the fourth RBR of the second network device to the terminal device 110.

[0155] It is to be noted that UL congestion may occur in one node as well, even in this case, the MN needs to send the updated RBR MAC CE. However, the terminal device 110 needs to determine whether to change the application bit rate based on the received RBR MAC CE

[0156] Alternatively or additionally, if the updated bit rate and the bit rate are the same, the terminal device 110 may further adjust the data splitting toward the first network device 120 and the second network device 130. For example, no change of application codec if the combined RBR from MN and SN is kept the same, but the data splitting towards the MN and the SN is to be adjusted according to the latest RBR MAC CE.

[0157] Additionally, if the updated bit rate is different from the bit rate, the terminal device 110 may further adjust the data splitting toward the first network device 120 the second network device 130 and the application bit rate. For example, if the combined RBR is changed, then the terminal device 110 may adjust application codec in addition to adjust data splitting towards the MN and the SN.

[0158] Fig. 8 illustrates a third example signaling chart illustrating an example process 800 according to some embodiments of the present disclosure. For the purpose of discussion, the process 800 will be described with reference to Fig. 1. The process 800 may involve the terminal device 110, the first network device 120 and the second network device 130. Itwould be appreciated that although the process 800 has been described in relation to the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios with similar issues. In some embodiments, the first network device 120 may be a master node of the terminal device, and the second network device 130 may be a secondary node of the terminal device. Alternatively, the second network device 130 may be a master node of the terminal device, and the first network device 120 may be a secondary node of the terminal device.

[0159] In the process 800,

[0160] the second network device 130 transmits 840 the second RBR of the second network device 845 to the first network device 120.

[0161] In some embodiments, the terminal device 110 may transmit 810 a first query for a first RBR 815 to the first network device 120. Correspondingly, the first network device 120 may receive 820 the first query for a first RBR 815 from the terminal device 110.

[0162] Alternatively or additionally, the terminal device 110 may further obtain configuration information associated with a MAC CE comprising the first RBR and the second RBR.

[0163] In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device 120. In some alternative embodiments, the MAC CE is a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be received from the first network device 120 and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device 130.

[0164] In some embodiments, the configuration information may be received from the first network device 120. Correspondingly, the first network device 120 may transmit the configuration information associated with the MAC CE to the terminal device 110. In some alternative embodiments, the configuration information may be predefined.

[0165] Continuing with reference to Fig. 8, the terminal device 110 may transmit 825 a second query for a second RBR of the second network device 830 to the second network device 130. Correspondingly, the second network device 130 may receive 835 the second query for the second RBR of the second network device 830.

[0166] After receiving 850 the second RBR of the second network device 845 from thesecond network device 130, the first network device 120 determines 855 a MAC CE comprising a first RBR of the first network device and the second RBR of the second network device 845.

[0167] Continuing with reference to Fig. 8, the first network device 120 transmits 860 the MAC CE 865 to the terminal device 110. In some embodiments, the MAC CE 865 may comprise a first field indicating the first RBR and a second field indicating the second RBR. Further, the MAC CE 865 may include a third field, which indicates a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID), a quality of service (QoS) flow ID (QFI) associated with the first network device, or any combination thereof.

[0168] After receiving 870 the MAC CE 865 from the first network device 120, the terminal device 110 determines 875 a bit rate to be used based on the MAC CE 865.

[0169] In some embodiments, the second network device 130 may further transmit the MAC CE comprising the first RBR of the first network device and the second RBR to the terminal device 110. Additionally, the terminal device 110 may further receive the MAC CE from the second network device 130.

[0170] In some embodiments, based on the MAC CE 865, the terminal device 110 may determine the first RBR of the first network device 120 and the second RBR of the second network device 130. Based on the first RBR and the second RBR, the terminal device 110 may determine the bit rate. Additionally, the terminal device 110 may determine the bit rate based on a sum of the first RBR and the second RBR.

[0171] Alternatively or additionally, based on the bit rate, the terminal device 110 may further adjust data splitting toward the first network device 120 and the second network device 130, an application bit rate of the terminal device 110, or both.

[0172] In some embodiments, the terminal device 110 may further receive a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device from the first network device 120. Based on the third MAC CE, the terminal device 110 may determine an updated bit rate to be used. In some embodiments, the third RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow. In addition, the updated bit rate to be used may be for one or more of a LCH, a LCG, a DRB, or a QoS flow.

[0173] Additionally, the fourth RBR may be transmitted via a fourth MAC CE. In addition, the fourth RBR may be for one or more of a LCH, a LCG, a DRB, or a QoS flow.

[0174] Alternatively or additionally, if the updated bit rate and the bit rate are the same, the terminal device 110 may further adjust the data splitting toward the first network device 120 and the second network device 130. Additionally, if the updated bit rate is different from the bit rate, the terminal device 110 may further adjust the data splitting toward the first network device 120 and the second network device 130, and adjust the application bit rate.

[0175] Fig. 9 illustrates an example process with the joint RBR MAC CE. The process 900 may involve a UE 901, a MN 902 and a SN 903. It is understood that the process 900 can be considered as a more specific example of process 200. Thus, the UE 901 of Fig. 9 may represent for example the terminal device 110 of Fig. 2, the MN 902 of Fig. 9 may represent for example the first network device 120 of Fig. 2, and the SN 903 of Fig. 9 may represent for example the second network device 130 of Fig. 2.

[0176] In the process 900, at 910, the MN 902 configures the UE 901 for joint RBR MAC CE. Alternatively, the usage of the joint RBR MAC CE may also be specified in 3 GPP specifications.

[0177] There are two options enabling the UE 901 to send the recommended bit rate query. In option 1, at 915, the UE 901 sends the recommended bit rate query to the MN 902. After the MN 902 receiving such MAC CE, at 920, the MN 902 will request recommended bit rate information from the SN 903 by sending the recommended bit rate query for certain LCH / DRB / QoS flow of the UE 901 to the SN 903. In option 2, the UE 901 sends recommended bit rate queries to both the MN 902 and the SN 903 at 925 and 930.

[0178] At 930, triggered by the message from the MN 902 or the UE 901, the SN 903 transmits the recommended bit rate to the MN 902. At 935, the MN 902 determines the recommended bit rate and generates the joint RBR MAC CE. At 940, the MN 902 performs the joint RBR MAC CE transmission.

[0179] At 945, the UE 901 determines the recommended bit rate from both the MN 902 and the SN 903 and adjusts data splitting towards the MN 902 and the SN 903. The UE 901 and / or the application further determines suitable bit rate based on the determined recommended bit rate. Depending on the format of MAC CE, the UE 901 may need to determine the recommended bit rate for one LCH / DRB / QoS flow and deliver the combined RBR to application. In addition, the UE 901 may adjust the data splitting toward MN and SN accordingly.

[0180] It should be noted that the gNB may determine the UL congestion state even withoutthe UE 901 sending a query MAC CE although it is included in Fig. 9. It is worth to note that it is a more logic assumption that UE sending query message to MN only (option 1), however, the process 900 also covered the scenario that UE 901 sends the query message to both MN 902 and SN 903 (option 2). In this case, SN 903 may send a recommended bit rate to MN 902 without the request from MN 902.

[0181] Fig. 10 shows a flowchart of an example method 1000 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the terminal device 110 with reference to Fig. 1.

[0182] At block 1010, the terminal device 110 receives, from the first network device, a first RBR of the first network device. At block 1020, the terminal device 110 receives, from a second network device, a second RBR of the second network device. At block 1040, the terminal device 110 determines, based on the first RBR and the second RBR, a bit rate to be used.

[0183] In some embodiments, the terminal device 110 may further transmit, to a first network device, a first query for a RBR.

[0184] In some embodiments, the terminal device 110 may further obtain configuration information associated with the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the first RBR and the second RBR are to be received from the first network device and the second network device respectively.

[0185] In some embodiments, the configuration information may indicate that the first RBR and the second RBR are triggered by at most one query for the RBR from the terminal device. In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0186] In some embodiments, the terminal device 110 may determine the bit rate by: determining the bit rate based on a sum of the first RBR and the second RBR. In some embodiments, the terminal device 110 may further adjust, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0187] In some embodiments, the terminal device 110 may further receive a third RBR from one of the first network device or the second network device, and determine an updated bit rate to be used based on the third RBR and a fourth RBR from another of the first networkdevice or the second network device.

[0188] In some embodiments, the terminal device 110 may further transmit, to the another of the first network device or the second network device, a query for updating an RBR, and receive the fourth RBR from the another of the first network device or the second network device.

[0189] In some embodiments, the first RBR may be received via a first medium access control (MAC) control element (MAC CE), the second RBR may be received via a second MAC CE, the third RBR may be received via a third MAC CE, or the fourth RBR may be received via a fourth MAC CE.

[0190] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0191] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0192] Fig. 11 shows a flowchart of an example method 1100 implemented at a first network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of the first network device 120 with reference to Fig. 1.

[0193] At block 1110, the first network device 120 transmits, to a second network device, a second query for a second RBR of the second network device. At block 1120, the first network device 120 transmits, to a terminal device, a first RBR of a first network device.

[0194] In some embodiments, the first network device 120 may further receive from a terminal device, a first query for an RBR.

[0195] In some embodiments, the first network device 120 may further transmit, to the terminal device, configuration information associated with the first RBR and the second RBR.In some embodiments, the configuration information may indicate that the first RBR and the second RBR are to be transmitted from the first network device and the second network device respectively.

[0196] In some embodiments, the configuration information may indicate that the first RBR and the second RBR are triggered by at most one query for the RBR from the terminal device.

[0197] In some embodiments, the first network device 120 may further transmit, to the terminal device, a third RBR. In some embodiments, the first network device may further receive, from the terminal device, a query for updating the RBR.

[0198] In some embodiments, the first RBR may be transmitted via a first medium access control (MAC) control element (MAC CE), the second RBR may be transmitted via a second MAC CE, or the third RBR may be transmitted via a third MAC CE.

[0199] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0200] In some embodiments, the first network device 120 may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0201] Fig. 12 shows a flowchart of an example method 1200 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1200 will be described from the perspective of the second network device 130 with reference to Fig. 1.

[0202] At block 1210, the second network device 130 receives, from a first network device, a second query for a second recommended bit rate (RBR) transmitted by a terminal device. At block 1220, the second network device 130 transmits, to the terminal device, the second RBR of the second network device.

[0203] In some embodiments, the second network device 130 may further transmit, to the terminal device, a third RBR. In some embodiments, the second network device 130 may further receive, from the terminal device, a query for updating the RBR.

[0204] In some embodiments, the first RBR may be transmitted via a first medium accesscontrol (MAC) control element (MAC CE), the second RBR may be transmitted via a second MAC CE, or the third RBR may be transmitted via a third MAC CE.

[0205] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0206] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0207] Fig. 13 shows a flowchart of an example method 1300 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1300 will be described from the perspective of the terminal device 110 with reference to Fig. 1.

[0208] At block 1310, the terminal device 110 receives, from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device. At block 1320, the terminal device 110 determines, based on the MAC CE, a bit rate to be used.

[0209] In some embodiments, the MAC CE may be in response to a query from the terminal device or is triggered by a change of a congestion state in at least one of the first network device or the second network device. In some embodiments, the terminal device 110 may further transmit, to the first network device, a query for an RBR, wherein the MAC CE is in response to the query.

[0210] In some embodiments, the terminal device 110 may further obtain configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device.

[0211] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be received from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device.

[0212] In some embodiments, the terminal device 110 may further receive the second MAC CE from the second network device. In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0213] In some embodiments, the terminal device 110 may determine the bit rate by: determining, based on the MAC CE, the first RBR of the first network device and the second RBR of the second network device, and determining the bit rate based on the first RBR and the second RBR.

[0214] In some embodiments, the terminal device 110 may determine the bit rate by: determining the bit rate based on a sum of the first RBR and the second RBR. In some embodiments, the terminal device 110 may further adjust, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0215] In some embodiments, the terminal device 110 may further receive, from the first network device, a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device, and determine an updated bit rate to be used based on the third MAC CE.

[0216] In some embodiments, the terminal device 110 may further adjust the data splitting toward the first network device and the second network device based on determining that the updated bit rate and the bit rate are the same, or adjust the data splitting toward the first network device and the second network device, and adjust the application bit rate based on determining that the updated bit rate is different from the bit rate.

[0217] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0218] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be forat least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0219] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0220] Fig. 14 shows a flowchart of an example method 1400 implemented at a first network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1400 will be described from the perspective of the first network device 120 with reference to Fig. 1.

[0221] At block 1410, the first network device 120 transmits, to the second network device, a first query for a recommended bit rate (RBR). At block 1420, the first network device 120 receives, from a second network device, a second RBR of the second network device. At block 1430, the first network device 120 determines a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device. At block 1440, the first network device 120 transmits, to a terminal device, the MAC CE.

[0222] In some embodiments, the first network device 120 may receive a second query for an RBR from the terminal device. In some embodiments, the first network device 120 may transmit the first query based on one of the following: receiving the second query from the terminal device, or determining a change of a congestion state at the first network device.

[0223] In some embodiments, the first network device 120 may further transmit, to the terminal device, configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be transmitted from the first network device.

[0224] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be transmitted from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be transmitted from the second network device.

[0225] In some embodiments, the first network device 120 may further based on determining at least one change of at least one congestion state in at least one of the first network device or the second network device, transmit a third MAC CE comprising a thirdRBR of the first network device and a fourth RBR of the second network device to the terminal device.

[0226] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0227] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0228] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0229] Fig. 15 shows a flowchart of an example method 1500 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1500 will be described from the perspective of the second network device 130 with reference to Fig. 1.

[0230] At block 1510, the second network device 130 transmits, to a first network device, a second recommended bit rate (RBR) of the second network device.

[0231] In some embodiments, the second RBR may be in response to a query from the first network device or is triggered by a change of a congestion state in the second network device.

[0232] In some embodiments, the second network device 130 may further receive, from a first network device, the query for an RBR.

[0233] In some embodiments, the second network device 130 may further transmit, to the terminal device, a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR.

[0234] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of alogical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0235] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, or the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0236] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0237] Fig. 16 shows a flowchart of an example method 1600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1600 will be described from the perspective of the terminal device 110 with reference to Fig. 1.

[0238] At block 1610, the terminal device 110 receives, from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first RBR of the first network device and the second RBR of a second network device. At block 1620, the terminal device 110 determines, based on the MAC CE, a bit rate to be used.

[0239] In some embodiments, the terminal device 110 may further transmit, to a first network device, a first query for a first recommended bit rate (RBR) of the first network device, and transmit, to a second network device, a second query for a second RBR of the second network device.

[0240] In some embodiments, the terminal device 110 may further obtain configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device.

[0241] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information indicates that the first MAC CE is to be received from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device.

[0242] In some embodiments, the terminal device 110 may further receive the second MACCE from the second network device. In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0243] In some embodiments, the terminal device 110 may determine the bit rate by: determining, based on the MAC CE, the first RBR and the second RBR, and determining the bit rate based on the first RBR and the second RBR.

[0244] In some embodiments, the terminal device 110 may determine the bit rate by: determining the bit rate based on a sum of the first RBR and the second RBR.

[0245] In some embodiments, the terminal device 110 may further adjust, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0246] In some embodiments, the terminal device 110 may further receive, from the first network device, a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device, and determine an updated bit rate to be used based on the third MAC CE.

[0247] In some embodiments, the terminal device 110 may further adjust the data splitting toward the first network device and the second network device based on determining that the updated bit rate and the bit rate are the same, or adjust the data splitting toward the first network device and the second network device, and adjust the application bit rate based on determining that the updated bit rate is different from the bit rate.

[0248] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0249] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0250] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device comprises a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device comprises the master node.

[0251] Fig. 17 shows a flowchart of an example method 1700 implemented at a first network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1700 will be described from the perspective of the first network device 120 with reference to Fig. 1.

[0252] At block 1710, the first network device 120 receives, from a second network device, a second recommended bit rate (RBR) of the second network device. At block 1720, the first network device 120 determines a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device. At block 1730, the first network device 120 transmits, to a terminal device, the MAC CE.

[0253] In some embodiments, the first network device 120 may receive a first query for the first RBR from the terminal device, wherein the MAC CE is in response to the first query.

[0254] In some embodiments, the first network device 120 may further transmit, to the terminal device, configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be transmitted from the first network device.

[0255] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be transmitted from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be transmitted from the second network device.

[0256] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0257] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB,or a QoS flow, or the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0258] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0259] Fig. 18 shows a flowchart of an example method 1800 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1800 will be described from the perspective of the second network device 130 with reference to Fig. 1.

[0260] At block 1810, the second network device 130 transmits, to a first network device, a second RBR of the second network device.

[0261] In some embodiments, the second network device 130 may further receive, from a terminal device, a second query for the second RBR.

[0262] In some embodiments, the second network device 130 may further transmit, to the terminal device, a medium access control (MAC) control element (MAC CE) comprising a first RBR and the second RBR.

[0263] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0264] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, or the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0265] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0266] In some embodiments, an apparatus capable of performing any of the method 1000 (for example, the terminal device 110) is provided. The apparatus may comprise means forperforming the respective steps of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0267] In some embodiments, the apparatus comprises means for receiving, from the first network device, a first RBR of the first network device, means for receiving, from a second network device, a second RBR of the second network device, and means for determining, based on the first RBR and the second RBR, a bit rate to be used.

[0268] In some embodiments, the apparatus may further comprise means for transmitting, to a first network device, a first query for an RBR. In some embodiments, the apparatus may further comprise means for obtaining configuration information associated with the first RBR and the second RBR.

[0269] In some embodiments, the configuration information may indicate that the first RBR and the second RBR are to be received from the first network device and the second network device respectively.

[0270] In some embodiments, the configuration information may indicate that the first RBR and the second RBR are triggered by at most one query for the RBR from the terminal device.

[0271] In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0272] In some embodiments, means for determining the bit rate may comprise means for determining the bit rate based on a sum of the first RBR and the second RBR.

[0273] In some embodiments, the apparatus may comprise means for adjusting, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0274] In some embodiments, the apparatus may further comprise means for receiving a third RBR from one of the first network device or the second network device, and means for determining an updated bit rate to be used based on the third RBR and a fourth RBR from another of the first network device or the second network device.

[0275] In some embodiments, the apparatus may further comprise means for transmitting, to the another of the first network device or the second network device, a query for updating an RBR, and means for receiving the fourth RBR from the another of the first network device or the second network device.

[0276] In some embodiments, the first RBR may be received via a first medium accesscontrol (MAC) control element (MAC CE), the second RBR may be received via a second MAC CE, the third RBR may be received via a third MAC CE, or the fourth RBR may be received via a fourth MAC CE.

[0277] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0278] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0279] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1000. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0280] In some embodiments, an apparatus capable of performing the method 1100 (for example, the first network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 1100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0281] In some embodiments, the apparatus comprises means for transmitting, to a second network device, a second query for a second RBR of the second network device, and means for transmitting, to a terminal device, a first RBR of a first network device.

[0282] In some embodiments, the apparatus may further comprise means for receiving from a terminal device, a first query for an RBR. In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, configuration information associated with the first RBR and the second RBR.

[0283] In some embodiments, the configuration information may indicate that the first RBR and the second RBR are to be transmitted from the first network device and the secondnetwork device respectively. In some embodiments, the configuration information may indicate that the first RBR and the second RBR are triggered by at most one query for the RBR from the terminal device.

[0284] In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, a third RBR. In some embodiments, the apparatus may further comprise means for receiving, from the terminal device, a query for updating the RBR.

[0285] In some embodiments, the first RBR may be transmitted via a first medium access control (MAC) control element (MAC CE), the second RBR may be transmitted via a second MAC CE, or the third RBR may be transmitted via a third MAC CE.

[0286] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0287] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0288] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1100. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0289] In some embodiments, an apparatus capable of performing the method 1200 (for example, the second network device 130) is provided. The apparatus may comprise means for performing the respective steps of the method 1200. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0290] In some embodiments, the apparatus comprises means for receiving, from a first network device, a second query for a second recommended bit rate (RBR) transmitted by a terminal device, and means for transmitting, to the terminal device, the second RBR of the second network device.

[0291] In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, a third RBR. In some embodiments, the apparatus may further comprise means for receiving, from the terminal device, a query for updating the RBR.

[0292] In some embodiments, the first RBR may be transmitted via a first medium access control (MAC) control element (MAC CE), the second RBR may be transmitted via a second MAC CE, or the third RBR may be transmitted via a third MAC CE.

[0293] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a logical channel group (LCG), a data radio bearer (DRB), or a quality of service (QoS) flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0294] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0295] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1200. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0296] In some embodiments, an apparatus capable of performing the method 1300 (for example, the terminal device 110) is provided. The apparatus may comprise means for performing the respective steps of the method 1300. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0297] In some embodiments, the apparatus comprises means for receiving, from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device, and means for determining, based on the MAC CE, a bit rate to be used.

[0298] In some embodiments, the MAC CE may be in response to a query from the terminal device or is triggered by a change of a congestion state in at least one of the first network device or the second network device. In some embodiments, the apparatus may further comprise means for transmitting, to the first network device, a query for an RBR, wherein the MAC CE is in response to the query.

[0299] In some embodiments, the apparatus may further comprise means for obtaining configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device.

[0300] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be received from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device.

[0301] In some embodiments, the apparatus may further comprise means for receiving the second MAC CE from the second network device. In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0302] In some embodiments, means for determining the bit rate may further comprise means for determining, based on the MAC CE, the first RBR of the first network device and the second RBR of the second network device, and means for determining the bit rate based on the first RBR and the second RBR.

[0303] In some embodiments, means for determining the bit rate may further comprise means for determining the bit rate based on a sum of the first RBR and the second RBR.

[0304] In some embodiments, the apparatus may further comprise means for adjusting, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0305] In some embodiments, the apparatus may further comprise means for receiving, from the first network device, a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device, and means for determining an updated bit rate to be used based on the third MAC CE.

[0306] In some embodiments, the apparatus may further comprise means for adjusting the data splitting toward the first network device and the second network device based on determining that the updated bit rate and the bit rate are the same, or means for adjusting the data splitting toward the first network device and the second network device and the application bit rate based on determining that the updated bit rate is different from the bit rate.

[0307] In some embodiments, the MAC CE may comprise: a first field indicating the firstRBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0308] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0309] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0310] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1300. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0311] In some embodiments, an apparatus capable of performing the method 1400 (for example, the first network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 1400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0312] In some embodiments, the apparatus comprises means for transmitting, to the second network device, a first query for a recommended bit rate (RBR), means for receiving, from a second network device, a second RBR of the second network device, means for determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and means for transmitting, to a terminal device, the MAC CE.

[0313] In some embodiments, the apparatus may comprise means for receiving a second query for an RBR from the terminal device.

[0314] In some embodiments, the apparatus may comprise means for transmitting the first query based on one of the following: receiving the second query from the terminal device, or determining a change of a congestion state at the first network device.

[0315] In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, configuration information associated with the MAC CE comprising the first RBR and the second RBR.

[0316] In some embodiments, the configuration information may indicate that the MAC CE is to be transmitted from the first network device.

[0317] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be transmitted from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be transmitted from the second network device.

[0318] In some embodiments, the apparatus may further comprise means for based on determining at least one change of at least one congestion state in at least one of the first network device or the second network device, transmitting a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device to the terminal device.

[0319] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0320] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0321] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0322] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1400. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0323] In some embodiments, an apparatus capable of performing any of the method 1500 (for example, the second network device 130) is provided. The apparatus may comprise means for performing the respective steps of the method 1500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0324] In some embodiments, the apparatus comprises means for transmitting, to a first network device, a second recommended bit rate (RBR) of the second network device.

[0325] In some embodiments, the second RBR may be in response to a query from the first network device or is triggered by a change of a congestion state in the second network device. In some embodiments, the apparatus may further comprise means for receiving, from a first network device, the query for an RBR. In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR.

[0326] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0327] In some embodiments, the congestion state may comprise an uplink congestion, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, or the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0328] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0329] In some embodiments, the apparatus may further comprise means for performingother steps in some embodiments of the method 1500. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0330] In some embodiments, an apparatus capable of performing the method 1600 (for example, the terminal device 110) is provided. The apparatus may comprise means for performing the respective steps of the method 1600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0331] In some embodiments, the apparatus comprises means for receiving, from the first network device, a medium access control (MAC) control element (MAC CE) comprising the first RBR and the second RBR of the first network device and the second RBR of a second network device, and means for determining, based on the MAC CE, a bit rate to be used.

[0332] In some embodiments, the apparatus may further comprise means for transmitting, to a first network device, a first query for a first recommended bit rate (RBR) of the first network device, means for transmitting, to a second network device, a second query for a second RBR of the second network device,

[0333] In some embodiments, the apparatus may further comprise means for obtaining configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be received from the first network device.

[0334] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information indicates that the first MAC CE is to be received from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device.

[0335] In some embodiments, the apparatus may further comprise means for receiving the second MAC CE from the second network device. In some embodiments, the configuration information may be received from the first network device, or the configuration information may be predefined.

[0336] In some embodiments, means for determining the bit rate may comprise means for determining, based on the MAC CE, the first RBR and the second RBR, and determining the bit rate based on the first RBR and the second RBR. In some embodiments, means for determining the bit rate may comprise means for determining the bit rate based on a sum ofthe first RBR and the second RBR.

[0337] In some embodiments, the apparatus may further comprise means for adjusting, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

[0338] In some embodiments, the apparatus may further comprise means for receiving, from the first network device, a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device, and means for determining an updated bit rate to be used based on the third MAC CE.

[0339] In some embodiments, the apparatus may further comprise means for adjusting the data splitting toward the first network device and the second network device based on determining that the updated bit rate and the bit rate are the same, or means for adjusting the data splitting toward the first network device and the second network device and the application bit rate based on determining that the updated bit rate is different from the bit rate.

[0340] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0341] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0342] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device comprises a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device comprises the master node.

[0343] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1600. In some embodiments, the means comprises at least one processor and at least one memory including computer program code,the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0344] In some embodiments, an apparatus capable of performing the method 1700 (for example, the first network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 1700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0345] In some embodiments, the apparatus comprises means for receiving, from a second network device, a second recommended bit rate (RBR) of the second network device, means for determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device, and means for transmitting, to a terminal device, the MAC CE.

[0346] In some embodiments, the apparatus may comprise means for receiving a first query for the first RBR from the terminal device, wherein the MAC CE is in response to the first query.

[0347] In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, configuration information associated with the MAC CE comprising the first RBR and the second RBR. In some embodiments, the configuration information may indicate that the MAC CE is to be transmitted from the first network device.

[0348] In some embodiments, the MAC CE may be a first MAC CE comprising the first RBR and the second RBR, and the configuration information may indicate that the first MAC CE is to be transmitted from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be transmitted from the second network device.

[0349] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0350] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, the third RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow, or the fourth RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0351] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0352] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0353] In some embodiments, an apparatus capable of performing any of the method 1800 (for example, the second network device 130) is provided. The apparatus may comprise means for performing the respective steps of the method 1800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0354] In some embodiments, the apparatus comprises means for transmitting, to a first network device, a second recommended bit rate (RBR) of a second network device.

[0355] In some embodiments, the apparatus may further comprise receiving, from a terminal device, a second query for the second RBR. In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, a medium access control (MAC) control element (MAC CE) comprising a first RBR and the second RBR.

[0356] In some embodiments, the MAC CE may comprise: a first field indicating the first RBR, a second field indicating the second RBR, and a third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

[0357] In some embodiments, the first RBR may be for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow, or the second RBR may be for at least one of a LCH, a LCG, a DRB, or a QoS flow.

[0358] In some embodiments, the first network device may comprise a master node of the terminal device, and the second network device may comprise a secondary node of the terminal device, or the first network device may comprise the secondary node, and the second network device may comprise the master node.

[0359] In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 1800. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0360] FIG. 19 is a simplified block diagram of a device 1900 that is suitable for implementing embodiments of the present disclosure. The device 1900 may be provided to implement the communication device, for example the terminal device 110 or the network device 120 as shown in Fig. 1. As shown, the device 1900 includes one or more processors 1910, one or more memories 1920 coupled to the processor 1910, and one or more communication modules 1940 coupled to the processor 1910.

[0361] The communication modules 1940 are for bidirectional communications. The communication modules 1940 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[0362] The processor 1910 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1900 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.

[0363] The memory 1920 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a read only memory (ROM) 1924, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1922 and other volatile memories that will not last in the power-down duration.

[0364] A computer program 1930 includes computer executable instructions that are executed by the associated processor 1910. The program 1930 may be stored in the ROM 1924. The processor 1910 may perform any suitable actions and processing by loading the program 1930 into the RAM 1922.

[0365] The embodiments of the present disclosure may be implemented by means of the program 1930 so that the device 1900 may perform any process of example embodiments of the disclosure as discussed with reference to Figs. 2 to 18. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0366] In some embodiments, the program 1930 may be tangibly contained in a computer readable medium which may be included in the device 1900 (such as in the memory 1920) or other storage devices that are accessible by the device 1900. The device 1900 may load the program 1930 from the computer readable medium to the RAM 1922 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 20 shows an example of the computer readable medium 2000 in form of CD or DVD. The computer readable medium has the program 1930 stored thereon.

[0367] Generally, various 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 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.

[0368] Example embodiments of 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 methods 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 and 1800 as described above with reference to Figs. 10-18. 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 embodiments. Machine-executable instructions for program modules may be executedwithin a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0369] Program code for carrying out methods of example embodiments 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.

[0370] 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, computer readable medium, and the like.

[0371] 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), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0372] 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 abovediscussions, 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 embodiments. Certain features that are described in the context of separate 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 embodiments separately or in any suitable sub-combination.

[0373] Although example embodiments of the present disclosure have been described in languages specific to structural features and / or methodological acts, it is to be understood that the example embodiments of 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.

Claims

WHAT IS CLAIMED IS:

1. A terminal device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:receive, from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device; anddetermine, based on the MAC CE, a bit rate to be used.

2. The terminal device of claim 1, wherein the terminal device is further caused to: transmit, to a first network device, a first query for the first RBR; andtransmit, to a second network device, a second query for the second RBR.

3. The terminal device of claim 1 or 2, wherein the terminal device is further caused to:obtain configuration information associated with the MAC CE comprising the first RBR and the second RBR.

4. The terminal device of claim 3, wherein the configuration information indicates that the MAC CE is to be received from the first network device.

5. The terminal device of claim 3, wherein the MAC CE is a first MAC CE comprising the first RBR and the second RBR, and the configuration information indicates that the first MAC CE is to be received from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be received from the second network device.

6. The terminal device of claim 5, wherein the terminal device is further caused to: receive the second MAC CE from the second network device.

7. The terminal device of any of claims 2-6, wherein one of the following: the configuration information is received from the first network device; orthe configuration information is predefined.

8. The terminal device of any of claims 1-7, wherein the terminal device is caused to determine the bit rate by:determining, based on the MAC CE, the first RBR and the second RBR; and determining the bit rate based on the first RBR and the second RBR.

9. The terminal device of claim 8, wherein the terminal device is caused to determine the bit rate by:determining the bit rate based on a sum of the first RBR and the second RBR.

10. The terminal device of any of claims 1-9, wherein the terminal device is further caused to:adjust, based on the bit rate, at least one of data splitting toward the first network device and the second network device or an application bit rate of the terminal device.

11. The terminal device of any of claims 1-10, wherein the terminal device is further caused to:receive, from the first network device, a third MAC CE comprising a third RBR of the first network device and a fourth RBR of the second network device; and determine an updated bit rate to be used based on the third MAC CE.

12. The terminal device of claim 11, wherein the terminal device is further caused to:adjust the data splitting toward the first network device and the second network device based on determining that the updated bit rate and the bit rate are the same; oradjust the data splitting toward the first network device and the second network device and the application bit rate based on determining that the updated bit rate is different from the bit rate.

13. The terminal device of any of claims 1-12, wherein the MAC CE comprises: a first field indicating the first RBR;a second field indicating the second RBR; anda third field indicating at least one of a logical channel identity (LCID), a logicalchannel group (LCG) identity (LCG ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

14. The terminal device of any of claims 1-13, wherein at least one of the following: the first RBR is for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow;the second RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow; the third RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow;the fourth RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow;the bit rate to be used is for at least one of a LCH, a LCG, a DRB, or a QoS flow or the updated bit rate to be used is for at least one of a LCH, a LCG, a DRB, or a QoS flow.

15. The terminal device of any of claims 1-14, wherein one of the following: the first network device comprises a master node of the terminal device, and the second network device comprises a secondary node of the terminal device; orthe first network device comprises the secondary node, and the second network device comprises the master node.

16. A first network device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to:receive, from a second network device, a second recommended bit rate (RBR) of the second network device;determine a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device; andtransmit, to a terminal device, the MAC CE.

17. The first network device of claim 16, wherein the first network device is caused to:receive a first query for the first RBR from the terminal device, wherein the wherein the MAC CE is in response to the first query.

18. The first network device of claim 16 or 17, wherein the first network device is further caused to:transmit, to the terminal device, configuration information associated with the MAC CE comprising the first RBR and the second RBR.

19. The first network device of claim 18, wherein the configuration information indicates that the MAC CE is to be transmitted from the first network device.

20. The first network device of claim 18, wherein the MAC CE is a first MAC CE comprising the first RBR and the second RBR, and the configuration information indicates that the first MAC CE is to be transmitted from the first network device and a second MAC CE comprising the first RBR and the second RBR is to be transmitted from the second network device.

21. The first network device of any of claims 16-20, wherein the MAC CE comprises:a first field indicating the first RBR;a second field indicating the second RBR; anda third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

22. The first network device of any of claims 16-21, wherein at least one of the following:the first RBR is for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow;the second RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow; the third RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow; or the fourth RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow.

23. The first network device of any of claims 16-22, wherein one of the following: the first network device comprises a master node of the terminal device, and the second network device comprises a secondary node of the terminal device; orthe first network device comprises the secondary node, and the second network device comprises the master node.

24. A second network device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second network device at least to:transmit, to a first network device, a second recommended bit rate (RBR) of a second network device.

25. The second network device of claim 24, wherein the second network device is further caused to:receive, from a terminal device, a second query for the second RBR.

26. The second network device of claim 25, wherein the second network device is further caused to:transmit, to the terminal device, a medium access control (MAC) control element (MAC CE) comprising a first RBR and the second RBR.

27. The second network device of claim 26, wherein the MAC CE comprises: a first field indicating the first RBR;a second field indicating the second RBR; anda third field indicating at least one of a logical channel identity (LCID), a logical channel group (LCG) identity (ID), a data radio bearer (DRB) ID (DRB ID) or a quality of service (QoS) flow ID (QFI) associated with the first network device.

28. The second network device of any of claims 25-27, wherein at least one of the following:the first RBR is for at least one of a logical channel (LCH), a LCG, a DRB, or a QoS flow; orthe second RBR is for at least one of a LCH, a LCG, a DRB, or a QoS flow.

29. The second network device of any of claims 25-28, wherein one of the following: the first network device comprises a master node of the terminal device, and thesecond network device comprises a secondary node of the terminal device; or the first network device comprises the secondary node, and the second network device comprises the master node.

30. A method comprising:receiving, at a terminal device and from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device; and determining, based on the MAC CE, a bit rate to be used.

31. A method comprising:receiving, at a first network device and from a second network device, a second recommended bit rate (RBR) of the second network device;determining a medium access control (MAC) control element (MAC CE) comprising a first RBR of the first network device and the second RBR of the second network device; andtransmitting, to a terminal device, the MAC CE.

32. A method comprising:transmitting, at a second network device and to a first network device, a second recommended bit rate (RBR) of a second network device.

33. An apparatus comprising:means for receiving, at a terminal device and from a first network device, a medium access control (MAC) control element (MAC CE) comprising a first recommended bit rate (RBR) of the first network device and a second RBR of a second network device; and means for determining, based on the MAC CE, a bit rate to be used.

34. An apparatus comprising:means for receiving, at a first network device and from a second network device, a second recommended bit rate (RBR) of the second network device;means for determining a medium access control (MAC) control element (MAC CE)comprising a first RBR of the first network device and the second RBR of the second network device; andmeans for transmitting, to a terminal device, the MAC CE.

35. An apparatus comprising:means for transmitting, at a second network device and to a first network device, a second recommended bit rate (RBR) of the second network device.

36. A computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of any of claims 30-32.

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