DELAY-BASED TRIGGER FOR ACTIVATING UPLINK SPLITTING CROSS REFERENCE TO RELATED APPLICATIONS:

[0001] This application claims priority from United States Provisional Application No. 62/490,846, filed on April 27, 2017. The entire contents of this earlier filed application are hereby incorporated by reference in their entirety.

BACKGROUND:

Field:

[0002] Embodiments of the invention generally relate to wireless or mobile communications networks, such as, but not limited to, the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE-Advanced (LTE-A), LTE-A Pro, and/or 5G radio access technology or new radio access technology (NR). Some embodiments may generally relate to radio bearer splitting, for example, between LTE, 5G, and/or NR radio access technologies.

Description of the Related Art:

[0003] Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) refers to a communications network including base stations, or Node Bs, and for example radio network controllers (RNC). UTRAN allows for connectivity between the user equipment (UE) and the core network. The RNC provides control functionalities for one or more Node Bs. The RNC and its corresponding Node Bs are called the Radio Network Subsystem (RNS). In case of E-UTRAN (enhanced UTRAN), no RNC exists and radio access functionality is provided by an evolved Node B (eNodeB or eNB) or many eNBs. Multiple eNBs are involved for a single UE connection, for example, in case of Coordinated Multipoint Transmission (CoMP) and in dual connectivity.

[0004] Long Term Evolution (LTE) or E-UTRAN refers to improvements of the UMTS through improved efficiency and services, lower costs, and use of new spectrum opportunities. In particular, LTE is a 3GPP standard that provides for uplink peak rates of at least, for example, 75 megabits per second (Mbps) per carrier and downlink peak rates of at least, for example, 300 Mbps per carrier. LTE supports scalable carrier bandwidths from 20 MHz down to 1 .4 MHz and supports both Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD).

[0005] As mentioned above, LTE may also improve spectral efficiency in networks, allowing carriers to provide more data and voice services over a given bandwidth. Therefore, LTE is designed to fulfill the needs for high-speed data and media transport in addition to high capacity voice support. Advantages of LTE include, for example, high throughput, low latency, FDD and TDD support in the same platform, an improved end- user experience, and a simple architecture resulting in low operating costs.

[0006] Certain releases of 3GPP LTE (e.g., LTE Rel-10, LTE Rel-1 1 , LTE Rel-12, LTE Rel-13) are targeted towards international mobile telecommunications advanced (IMT-A) systems, referred to herein for convenience simply as LTE-Advanced (LTE-A).

[0007] LTE-A is directed toward extending and optimizing the 3GPP LTE radio access technologies. A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is a more optimized radio system fulfilling the international telecommunication union-radio (ITU-R) requirements for IMT-Advanced while maintaining backward compatibility. One of the key features of LTE- A, introduced in LTE Rel-10, is carrier aggregation, which allows for increasing the data rates through aggregation of two or more LTE carriers.

[0008] 5 ^th generation (5G) or new radio (NR) wireless systems refer to the next generation (NG) of radio systems and network architecture. It is estimated that 5G will provide bitrates on the order of 10-20 Gbit/s. 5G will support at least enhanced mobile broadband (eMBB) and ultra-reliable low-latency-communication (URLLC). 5G is also expected to increase network expandability up to hundreds of thousands of connections. The signal technology of 5G is anticipated to be improved for greater coverage as well as spectral and signaling efficiency. 5G is expected to deliver extreme broadband and ultra-robust, low latency connectivity and massive networking to support the Internet of Things (loT). With loT and machine-to-machine (M2M) communication becoming more widespread, there will be a growing need for networks that meet the needs of lower power, low data rate, and long battery life. In 5G or NR, the node B or eNB may be referred to as a next generation node B (gNB).

SUMMARY:

[0009] One embodiment is directed to a method that may include determining, by a UE, a condition based on the duration of time that UL data resides in a buffer. In an embodiment, the method may also include reporting (or not reporting) UL data available at the buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) based on the determined condition.

[0010] Another embodiment is directed to an apparatus that may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to determine a condition based on the duration of time that UL data resides in a buffer, and to report (or not report) UL data available at the buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) based on the determined condition.

[0011] Another embodiment is directed to an apparatus that may include determining means for determining a condition based on the duration of time that UL data resides in a buffer. In an embodiment, the apparatus may also include means for reporting (or not reporting) UL data available at the buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) depending on the determined condition.

[0012] Another embodiment is directed to a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: determining a condition based on the duration of time that UL data resides in a buffer. In an embodiment, the method may also include reporting (or not reporting) UL data available at the buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) based on the determined condition.

[0013] Another embodiment is directed to a method that may include configuring a UE PDCP with a time-duration limit value to use, and receiving, by a network node, one or more BSRs indicating that UL data is available in a buffer of the UE. The method may further include scheduling, based on the received BSR(s), a UE in the UL and causing UL data to be submitted from the buffer to lower layers.

[0014] Another embodiment is directed to an apparatus that may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to configure a UE PDCP with a time-duration limit value to use, receive one or more BSRs indicating that UL data is available in a buffer of a UE, and to schedule based on the received BSR(s), a UE in the UL thereby causing UL data to be submitted from the buffer to lower layers.

[0015] Another embodiment is directed to an apparatus that may include configuring means for configuring a UE PDCP with a time-duration limit value to use, and receiving means for receiving one or more BSRs indicating that UL data is available in a buffer of the UE. The apparatus may further include scheduling means for scheduling, based on the received BSR(s), a UE in the UL and causing UL data to be submitted from the buffer to lower layers.

[0016] Another embodiment is directed to a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: configuring a UE PDCP with a time-duration limit value to use, and receiving one or more BSRs indicating that UL data is available in a buffer of the UE. The method may further include scheduling, based on the received BSR(s), a UE in the UL and causing UL data to be submitted from the buffer to lower layers.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0017] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0018] Fig. 1 illustrates an example of a signaling diagram, according to one embodiment;

[0019] Fig. 2a illustrates an example block diagram of an apparatus, according to an embodiment;

[0020] Fig. 2b illustrates an example block diagram of an apparatus, according to another embodiment;

[0021] Fig. 3a illustrates an example flow chart of a process, according to an embodiment; and

[0022] Fig. 3b illustrates an example flow chart of a process, according to another embodiment.

DETAILED DESCRIPTION:

[0023] It will be readily understood that the components of the invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of systems, methods, apparatuses, and computer program products relating to radio bearer splitting, for example, between LTE and new radio access technology (NR) or 5G, as represented in the attached figures and described below, is not intended to limit the scope of the invention but is representative of selected embodiments of the invention. [0024] The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases "certain embodiments," "some embodiments," or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearances of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0025] Additionally, if desired, the different functions discussed below may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the described functions may be optional or may be combined. As such, the following description should be considered as merely illustrative of the principles, teachings and embodiments of this invention, and not in limitation thereof.

[0026] Certain embodiments of the present disclosure relate to split bearer. For example, some embodiments may be directed to splitting of the uplink on such bearers, into data transmitted to a master cell group (MCG) and to a secondary cell group (SCG). One embodiment is directed to bearers split between LTE and NR, which are in the scope of the 3GPP Rel-15 Work Item (Wl) description in RP-170847. 3GPP technical report (TR) 38.804 provides additional description of the split bearer.

[0027] Splitting of the uplink was standardized in connection with LTE dual connectivity (DC). The rule for the UE to report uplink data available at packet data convergence protocol (PDCP) to MCG and/or SCG has been specified in 3GPP LTE

PDCP technical specification (TS) 36.323. In particular, 3GPP TS 36.323 section 4.5 specified the following:

For split bearers, when indicating the data available for transmission to a MAC entity for BSR triggering and Buffer Size calculation, the UE shall:

- if ul-DataSplitThreshold is configured and the data available for transmission is larger than or equal to ul-DataSplitThreshold:

indicate the data available for transmission to both the MAC entity configured for SCG and the MAC entity configured for MCG;

- else:

if ul-DataSplitDRB-ViaSCG is set to TRUE by upper layer

[3]: indicate the data available for transmission to the MAC entity configured for SCG only;

if ul-DataSplitThreshold is configured, indicate the data available for transmission as 0 to the MAC entity configured for MCG;

else:

indicate the data available for transmission to the MAC entity configured for MCG only;

if ul-DataSplitThreshold is configured, indicate the data available for transmission as 0 to the MAC entity configured for SCG.

[0028] In the above, the parameters in italics (e.g., ul-DataSplitThreshold, ul- DataSplitDRB-ViaSCG) are configured by radio resource control (RRC). In short, the data is reported to the cell group configured to be in an overflow role only when a threshold amount of data is exceeded.

[0029] It is noted that, while one use case for certain embodiments is genuine splitting where a given PDCP protocol data unit (PDU) is transmitted to one cell group only, other embodiments may also find use in activating duplication of uplink data to a second cell group.

[0030] The utility of the parameter, ul-DataSplitThreshold, in the 3GPP LTE PDCP specification (TS 36.323) is questionable, because whether or not a given amount of uplink data available at PDCP actually justifies splitting the uplink depends on the throughput that the cell group, to which the uplink data is anyway reported, is serving the bearer. In other words, assuming that the UE has X bytes of uplink data available at PDCP for the split bearer, it may make sense to report it to both the configured cell groups if the bearer is currently being served at 1 Mbps, while that may be totally unnecessary if the bearer is being served at 1 Gbps instead. Especially if the cell group configured to the overflow role has longer intrinsic delay (such as when it is not the one co-located with the network-side PDCP entity for the split bearer), activation of the uplink splitting comes with the cost of increasing the end-to-end delay perceived at higher layers such as TCP, and should therefore not be done too lightly.

[0031] One embodiment of the present disclosure provides that whether or not the UE reports uplink data available at PDCP for the split bearer to both the configured cell groups may depend on the time duration which uplink data (in general, not the same as the uplink data available at the PDCP) resides in the PDCP buffer waiting for transmission (for example until confirmation of successful delivery, or being submitted to lower layers if no such confirmations are used on the bearer). This time duration may be directly observed, or may be a calculated prediction based on past observed uplink throughput, observed radio conditions, and/or the amount of data in buffer.

[0032] In an embodiment, the limit value for the UE to apply to this time duration may be configured to the UE by the network. According to certain embodiments, the time- duration limit value that the UE will apply may be configured, for example, over RRC.

[0033] In an embodiment, at reception of a PDCP service data unit (SDU) from upper layers, a timer (newTimer) may be started for this SDU. According to some embodiments, the timer may be stopped when, for bearers mapped on radio link control (RLC) acknowledged mode (AM), a confirmation of successful delivery is received. In other embodiments, the timer may be stopped when, for bearers mapped on RLC unacknowledged mode (UM), the PDU formed from the SDU is submitted to lower layer.

[0034] According to one embodiment, when indicating the data available for transmission to a medium access control (MAC) entity for buffer status report (BSR) triggering and buffer size calculation, the UE may, if an uplink SDU or corresponding PDU is stored for which the timer (newTimer) expired, indicate data available for transmission to both the MAC entity configured for SCG and the MAC entity configured for MCG.

[0035] Fig. 1 illustrates an example sequence diagram depicting possible signaling between network nodes, according to an embodiment. As illustrated in Fig. 1 , at 1 , MeNB may configure the UE PDCP with a time-duration limit value to use. At 2, UL data may arrive in UE PDCP buffer from higher layer. At 3, the UL data "available" may be reported in MAC buffer status report (BSR) to the network. For example, in an embodiment, UL data may be reported to the MCG eNB (MeNB), the SCG eNB (SeNB), or to both the MeNB and SeNB, depending on the duration of time that UL data resides in the PDCP buffer waiting for transmission. It should be noted that the MeNB depicted in Fig. 1 may represent a MeNB or MgNB; similarly, the SeNB depicted in Fig. 1 may represent a SeNB or SgNB.

[0036] Continuing with Fig. 1 , based on the BSR(s), at 4, the UE may be scheduled in the UL by the network, causing UL data to be submitted from PDCP to lower layer, such as RLC AM or RLC UM. In certain embodiments, PDCP data submitted to RLC UM may be discarded at PDCP at that time as there is no reason to keep it. According to some embodiments, PDCP data submitted to RLC AM may only be discarded at PDCP after a confirmation of successful delivery of the data is received, for example from RLC or from the peer PDCP entity (before that happens, handover can occur in which case PDCP would need to re-transmit the data not yet acknowledged, such as all data following a packet whose successful delivery is not yet confirmed). [0037] Fig. 2a illustrates an example of an apparatus 10 according to an embodiment. In an embodiment, apparatus 10 may be a node, host, or server in a communications network or serving such a network. For example, apparatus 10 may be a base station, a node B, an evolved node B, 5G node B or access point, next generation node B (NG-NB or gNB), WLAN access point, mobility management entity (MME), or subscription server associated with a radio access network, such as a GSM network, LTE network, 5G or NR.

[0038] It should be understood that apparatus 10 may be comprised of an edge cloud server as a distributed computing system where the server and the radio node may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection, or they may be located in a same entity communicating via a wired connection. It should be noted that one of ordinary skill in the art would understand that apparatus 10 may include components or features not shown in Fig. 2a.

[0039] As illustrated in Fig. 2a, apparatus 10 may include a processor 12 for processing information and executing instructions or operations. Processor 12 may be any type of general or specific purpose processor. In fact, processor 12 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application- specific integrated circuits (ASICs), and processors based on a multi-core processor architecture, as examples. While a single processor 12 is shown in Fig. 2a, multiple processors may be utilized according to other embodiments. For example, it should be understood that, in certain embodiments, apparatus 10 may include two or more processors that may form a multiprocessor system (i.e., in this case processor 12 represents a multiprocessor) that may support multiprocessing. In certain embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0040] Processor 12 may perform functions associated with the operation of apparatus 10 which may include, for example, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 10, including processes related to management of communication resources.

[0041] Apparatus 10 may further include or be coupled to a memory 14 (internal or external), which may be coupled to processor 12, for storing information and instructions that may be executed by processor 12. Memory 14 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and removable memory. For example, memory 14 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, hard disk drive (HDD), or any other type of non-transitory machine or computer readable media. The instructions stored in memory 14 may include program instructions or computer program code that, when executed by processor 12, enable the apparatus 10 to perform tasks as described herein.

[0042] In an embodiment, apparatus 10 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 12 and/or apparatus 10.

[0043] In some embodiments, apparatus 10 may also include or be coupled to one or more antennas 15 for transmitting and receiving signals and/or data to and from apparatus 10. Apparatus 10 may further include or be coupled to a transceiver 18 configured to transmit and receive information. The transceiver 18 may include, for example, a plurality of radio interfaces that may be coupled to the antenna(s) 15. The radio interfaces may correspond to a plurality of radio access technologies including one or more of GSM, NB-loT, LTE, 5G, WLAN, Bluetooth, BT-LE, NFC, radio frequency identifier (RFID), ultrawideband (UWB), and the like. The radio interface may include components, such as filters, converters (for example, digital-to-analog converters and the like), mappers, a Fast Fourier Transform (FFT) module, and the like, to generate symbols for a transmission via one or more downlinks and to receive symbols (for example, via an uplink). As such, transceiver 18 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 15 and demodulate information received via the antenna(s) 15 for further processing by other elements of apparatus 10. In other embodiments, transceiver 18 may be capable of transmitting and receiving signals or data directly.

[0044] In an embodiment, memory 14 may store software modules that provide functionality when executed by processor 12. The modules may include, for example, an operating system that provides operating system functionality for apparatus 10. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 10. The components of apparatus 10 may be implemented in hardware, or as any suitable combination of hardware and software. [0045] In certain embodiments, apparatus 10 may be a network node or RAN node, such as a base station, access point, node B, eNB, 5G or new radio node B (gNB) or access point, WLAN access point, or the like. For example, in certain embodiments, apparatus 10 may be a MeNB (or MgNB) and/or SeNB (or SgNB) in a split bearer configuration. For instance, in some embodiments, the bearers may be split between LTE and NR; however, in other embodiments, the bearers may be split between other radio access technologies. According to certain embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to perform the functions associated with any of the embodiments described herein.

[0046] In some embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to configure a UE PDCP with a time-duration limit value to use. In an embodiment, apparatus 10 may also be controlled by memory 14 and processor 12 to receive one or more BSRs indicating that UL data is available in a PDCP buffer of a UE. According to one embodiment, transmission of the BSR(s) to apparatus 10 may be triggered based on a time duration that UL data resides in the PDCP buffer waiting for transmission. In certain embodiments, the time duration may be directly observed, or may be a calculated prediction based on past observed uplink throughput, observed radio conditions, and/or the amount of data in buffer. In some embodiments, the limit value for a UE to apply to the time duration may be configured to the UE by the network (e.g., apparatus 10).

[0047] Based on the received BSR(s), apparatus 10 may be controlled by memory 14 and processor 12 to schedule the UE in the UL thereby causing UL data to be submitted from PDCP to lower layer, such as RLC AM or RLC UM. In some embodiments, PDCP data submitted to RLC UM may be discarded at PDCP at that time since there is no reason to keep it; while PDCP data submitted to RLC AM may be discarded at PDCP after a confirmation of successful delivery of the data is received. It is noted that, before an ACK is received, it is possible that handover may occur in which case PDCP would to retransmit the data not yet acknowledged.

[0048] Fig. 2b illustrates an example of an apparatus 20 according to another embodiment. In an embodiment, apparatus 20 may be a node or element in a communications network or associated with such a network, such as a UE, mobile equipment (ME), mobile station, mobile device, stationary device, loT device, or other device. As described herein, UE may alternatively be referred to as, for example, a mobile station, mobile equipment, mobile unit, mobile device, user device, subscriber station, wireless terminal, tablet, smart phone, loT device or NB-loT device, or the like. As one example, apparatus 20 may be implemented in, for instance, a wireless handheld device, a wireless plug-in accessory, or the like.

[0049] In some example embodiments, apparatus 20 may include one or more processors, one or more computer-readable storage medium (for example, memory, storage, and the like), one or more radio access components (for example, a modem, a transceiver, and the like), and/or a user interface. In some embodiments, apparatus 20 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-loT, Bluetooth, NFC, and any other radio access technologies. It should be noted that one of ordinary skill in the art would understand that apparatus 20 may include components or features not shown in Fig. 2b.

[0050] As illustrated in Fig. 2b, apparatus 20 may include or be coupled to a processor 22 for processing information and executing instructions or operations. Processor 22 may be any type of general or specific purpose processor. In fact, processor 22 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application- specific integrated circuits (ASICs), and processors based on a multi-core processor architecture, as examples. While a single processor 22 is shown in Fig. 2b, multiple processors may be utilized according to other embodiments. For example, it should be understood that, in certain embodiments, apparatus 20 may include two or more processors that may form a multiprocessor system (i.e., in this case processor 22 represents a multiprocessor) that may support multiprocessing. In certain embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0051] Processor 22 may perform functions associated with the operation of apparatus 20 including, without limitation, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 20, including processes related to management of communication resources.

[0052] Apparatus 20 may further include or be coupled to a memory 24 (internal or external), which may be coupled to processor 22, for storing information and instructions that may be executed by processor 22. Memory 24 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and removable memory. For example, memory 24 can be comprised of any combination of random access memory (RAM), read only memory (ROM), static storage such as a magnetic or optical disk, or any other type of non- transitory machine or computer readable media. The instructions stored in memory 24 may include program instructions or computer program code that, when executed by processor 22, enable the apparatus 20 to perform tasks as described herein.

[0053] In an embodiment, apparatus 20 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 22 and/or apparatus 20.

[0054] In some embodiments, apparatus 20 may also include or be coupled to one or more antennas 25 for receiving a downlink signal and for transmitting via an uplink from apparatus 20. Apparatus 20 may further include a transceiver 28 configured to transmit and receive information. The transceiver 28 may also include a radio interface (e.g., a modem) coupled to the antenna 25. The radio interface may correspond to a plurality of radio access technologies including one or more of GSM, LTE, LTE-A, 5G, NR, WLAN, NB-loT, Bluetooth, BT-LE, NFC, RFID, UWB, and the like. The radio interface may include other components, such as filters, converters (for example, digital-to-analog converters and the like), symbol demappers, signal shaping components, an Inverse Fast Fourier Transform (IFFT) module, and the like, to process symbols, such as OFDMA symbols, carried by a downlink or an uplink.

[0055] For instance, transceiver 28 may be configured to modulate information on to a carrier waveform for transmission by the antenna(s) 25 and demodulate information received via the antenna(s) 25 for further processing by other elements of apparatus 20. In other embodiments, transceiver 28 may be capable of transmitting and receiving signals or data directly. Apparatus 20 may further include a user interface, such as a graphical user interface or touchscreen.

[0056] In an embodiment, memory 24 stores software modules that provide functionality when executed by processor 22. The modules may include, for example, an operating system that provides operating system functionality for apparatus 20. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 20. The components of apparatus 20 may be implemented in hardware, or as any suitable combination of hardware and software. [0057] According to one embodiment, apparatus 20 may be a UE, mobile device, mobile station, ME, loT device and/or NB-loT device, for example. According to certain embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to perform t e functions associated with embodiments described herein. For example, in some embodiments, apparatus 20 may be configured to perform one or more of the processes depicted in any of the flow charts or signaling diagrams described herein. According to certain embodiments, for example after UL data (e.g., a PDCP SDU) arrives in a PDCP buffer from higher layer, apparatus 20 may be controlled by memory 24 and processor 22 to determine a condition based on a time duration that the UL data resides in the PDCP buffer waiting for transmission. In an embodiment, apparatus 20 may then be controlled by memory 24 and processor 22 to report (or not report) UL data available at the PDCP buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) depending on the determined condition.

[0058] According to one embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to determine a condition based on the time duration that the UL data resides in the PDCP buffer waiting for transmission by starting a timer (e.g., newTimer) when a PDCP SDU is received from higher layer(s). Apparatus 20 may then be controlled by memory 24 and processor 22 to stop the timer when, for bearer(s) mapped on RLC AM, a confirmation of successful delivery is received, or, when, for bearer(s) mapped on RLC UM, the PDU formed from the SDU is submitted to lower layer. When an UL SDU or corresponding PDU is stored for which the timer has expired, apparatus 20 may be controlled by memory 24 and processor 22 to trigger the transmission of BSR(s) indicating UL data available for transmission to both the MAC entity configured for SCG (e.g., SeNB or SgNB) and the MAC entity configured for MCG (e.g., MeNB or MgNB).

[0059] Fig. 3a illustrates an example flow diagram of a method, according to one embodiment. The method of Fig. 3a may be performed, for example, by a network node, such as a base station, access point, eNB, gNB, or the like. As illustrated in Fig. 3a the method may include, at 300, configuring a UE PDCP with a time-duration limit value to use and, at 305, receiving, for example by a network entity, one or more BSRs indicating that UL data is available in a buffer of a UE. In an embodiment, the buffer may be a PDCP buffer. According to one embodiment, transmission of the BSR(s) to the network entity may be triggered based on a time duration that the UL data resides in the buffer waiting for transmission. In certain embodiments, the time duration may be directly observed, or may be a calculated prediction based on past observed uplink throughput, observed radio conditions, and/or the amount of data in buffer. In some embodiments, the limit value for a UE to apply to t e time duration may be configured to the UE by the network node. The method may further include, at 310, scheduling, based on the received BSR(s), the UE in the UL and causing UL data to be submitted from PDCP to lower layer, such as RLC AM or RLC UM. In some embodiments, PDCP data submitted to RLC UM may be discarded at PDCP at that time since there is no reason to keep it; while PDCP data submitted to RLC AM may be discarded at PDCP after a confirmation of successful delivery of the data is received.

[0060] Fig. 3b illustrates an example flow diagram of a method, according to one embodiment. The method of Fig. 3b may be performed, for example, by a UE, mobile station, mobile device, loT device, MTC device, or the like. As illustrated in Fig. 3b the method may include, at 350, for example after UL data (e.g., a PDCP SDU) arrives in a PDCP buffer from higher layer, determining a condition based on the duration of time that the UL data resides in the PDCP buffer waiting for transmission. In an embodiment, the method may also include, at 360, reporting (or not reporting) UL data available at the PDCP buffer for a split bearer to one or both of the configured cell groups (e.g., MCG or SCG) based on the determined condition. In one embodiment, the determining of the condition based on the time duration that the UL data resides in the PDCP buffer may further include starting a timer (e.g., newTimer) when a PDCP SDU is received from higher layer(s), and stopping the timer when, for bearer(s) mapped on RLC AM, a confirmation of successful delivery is received, or, when, for bearer(s) mapped on RLC UM, the PDU formed from the SDU is submitted to lower layer. In an embodiment, the reporting of the UL data available at the PDCP buffer may further include, when an UL SDU or corresponding PDU is stored for which the timer has expired, triggering the transmission of BSR(s) indicating UL data available for transmission to both the MAC entity configured for SCG (e.g., SeNB or SgNB) and the MAC entity configured for MCG (e.g., MeNB or MgNB).

[0061] In view of the above, embodiments of the invention provide several technical effects and/or improvements and/or advantages. For example, certain embodiments provide an advantageous bearer splitting arrangement that can, for example, improve performance and throughput of network nodes including, for example, base stations, eNBs, gNBs and/or UEs. Accordingly, the use of embodiments of the invention result in improved functioning of communications networks and their nodes.

[0062] In some embodiments, the functionality of any of the methods, processes, signaling diagrams, or flow charts described herein may be implemented by software and/or computer program code or portions of code stored in memory or other computer readable or tangible media, and executed by a processor.

[0063] In certain embodiments, an apparatus may be included or be associated with at least one software application, module, unit or entity configured as arithmetic operation(s), or as a program or portions of it (including an added or updated software routine), executed by at least one operation processor. Programs, also called computer program products or computer programs, including software routines, applets and macros, may be stored in any apparatus-readable data storage medium and include program instructions to perform particular tasks.

[0064] A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out embodiments described herein. The one or more computer-executable components may include at least one software code or portions of code. Modifications and configurations required for implementing the functionality of an embodiment may be performed as routine(s), which may be implemented as added or updated software routine(s). In some embodiments, software routine(s) may be downloaded into the apparatus.

[0065] Software or a computer program code or portions of code may be in a source code form, object code form, or in some intermediate form, and may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and/or software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital device or it may be distributed amongst a number of devices or computers. The computer readable medium or computer readable storage medium may be a non-transitory medium.

[0066] In other embodiments, the functionality may be performed by hardware, for example through the use of an application specific integrated circuit (ASIC), a programmable gate array (PGA), a field programmable gate array (FPGA), or any other combination of hardware and software. In yet another embodiment, the functionality may be implemented as a signal, a non-tangible means that can be carried by an electromagnetic signal downloaded from the Internet or other network.

[0067] According to an embodiment, an apparatus, such as a node, device, or a corresponding component, may be configured as a computer or a microprocessor, such as single-chip computer element, or as a chipset, including at least a memory for providing storage capacity used for arithmetic operation(s) and an operation processor for executing the arithmetic operation.

[0068] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of example embodiments, reference should be made to the appended claims.