System and method for providing RRC inactive mode enhanced paging for mobile terminal small data transfer

Abstract

A method for performing a paging procedure improved by a user equipment (UE) includes receiving, from a radio access network (RAN) node, information for determining a position in a first channel allocated to the UE for downlink data transmission while the UE is in a radio resource control (RRC) inactive mode, transitioning from an RRC connected mode to the RRC inactive mode, reading a paging message indicating the UE for paging, and reading downlink data at a position in the first channel determined by the UE based on the received information while the UE is in the RRC inactive mode.

Description

Background Art

[0001] In related communication standards (e.g., 3GPP specifications for LTE, 5G, etc.), the Radio Resource Control (RRC) protocol defines the signaling exchanged on the radio interface between a User Equipment (UE) and a base station. The RRC is used for various different functions including connection establishment and release, broadcast of system information related to the characteristics of the radio interface, radio bearer establishment, RRC connection mobility procedures (i.e., handover), and paging notifications.

[0002] The operation of the RRC is guided by a state machine that defines the various RRC states that a UE can be in. These states include RRC connected, RRC idle, and RRC inactive (introduced in 5G). Different RRC states (or modes) determine the control, mobility management, and amount of radio resources allocated to the UE, and the amount of energy consumed in each different state also varies.

[0003] In particular, the RRC idle mode is the mode when the UE's power is first turned on and consumes the least amount of energy. The UE can transition to the RRC connected mode along with the connection establishment procedure to the Radio Access Network (RAN), followed by the initial attachment to the core network and the setup of the default bearer set for data transfer. In the RRC connected mode, the largest amount of resources is allocated to the UE and it consumes the most energy. To achieve power saving, if there is no activity for a certain period, the UE transitions to the RRC inactive mode. In the inactive mode, the RRC context (i.e., the parameters necessary for communication between the device and the network) is maintained at both the device and the base station and the core network connection is kept, but the RRC connection is interrupted to save the UE's battery power.

[0004] In both the RRC idle and inactive modes, the UE can receive paging messages from the network. Paging is a mechanism for the network to inform the UE that something is happening. Figure 1 illustrates the paging procedure in the related art. Referring to Figure 1, the UE transitions from the RRC connected state to the inactive state using the RRC release procedure. For this purpose, an RRC release message is sent from the base station (gNB) to the UE.

[0005] Figure 2 illustrates the definition of the RRC release message in the related art. Referring to Figure 2, the RRC release message includes a SuspendConfig field that indicates the configuration for the RRC inactive state. Among the information, the paging cycle (ran-PagingCycle), which is the UE-specific cycle for paging initiated by the RAN or the discontinuous reception (DRX) cycle, is provided in SuspendConfig.

[0006] Returning to Figure 1, while in the idle or inactive state, the UE wakes up periodically and monitors the physical downlink control channel (PDCCH) for paging indications in one paging occasion per DRX cycle. The paging occasion is monitored based on the paging search space defined for paging, which is included in the cell-specific configuration parameters (PDCCH-ConfigCommon) of the PDCCH.

[0007] When there is some downlink (DL) data to be sent to a UE in RRC idle or inactive mode, the access and mobility function (AMF) of the core network may initiate a paging procedure with the base station, and the base station may send a paging indication encrypted by the P-RNTI (paging radio network temporary identifier). The UE uses the P-RNTI to scramble or decrypt the paging indication in the PDCCH and checks for paging messages on the paging channel (PCH) of the physical downlink shared channel (PDSCH).

[0008] Figure 3 illustrates the definition of a paging message in the related art. Referring to Figure 3, in the paging message transmitted on the PCH, the UE is paged via the S-TMSI (Serving Temporary Mobile Subscriber Identity) that uniquely identifies each UE. The UE decodes the paging message and checks whether its S-TMSI is included in the paging record. The paging record may optionally include an access type parameter indicating whether the paging message is due to a protocol data unit (PDU) session from non-3GPP access.

[0009] Returning to Figure 1, in the paging record of the paging message, when the UE finds its own ID (S-TMSI), it performs an RRC connection setup to receive DL data in the RRC connection mode. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] As described above, in the paging procedure of the related art, in order for the UE to receive data, the UE has to decode the paging message, transition to the RRC connected state, activate the bearer, and execute the RRC connection setup (RRC resume procedure) to schedule the downlink data. Therefore, even for receiving a small amount of data, the amount of signaling and radio resource overhead involved increases proportionally, resulting in inefficient resource utilization, increased power consumption, and increased latency.

Means for Solving the Problem

[0011] Aspects of one or more embodiments provide an improved paging procedure in which a user equipment (UE) can receive downlink data in a Radio Resource Control (RRC) inactive mode without performing an RRC resume procedure or transitioning to an RRC connected state.

[0012] Aspects of one or more embodiments provide a system and method for transmitting small data that can be read by a UE in an RRC inactive mode after decoding a paging message without transitioning to an RRC connected state, at a preconfigured PDSCH position.

[0013] According to aspects of one or more embodiments, a method for performing an improved paging procedure by a user equipment (UE) is provided. The method includes receiving, from a Radio Access Network (RAN) node, information for determining a position in a first channel allocated to the UE for downlink data transmission while the UE is in a Radio Resource Control (RRC) inactive mode, transitioning from an RRC connected mode to an RRC inactive mode, reading a paging message indicating the UE for paging, and reading downlink data at a position in the first channel determined by the UE based on the received information while the UE is in the RRC inactive mode.

[0014] Reading downlink data may include reading downlink data at a position in a first channel determined by the UE based on the received information, based on determining that the paging message includes information indicating that the cause of paging is small data transmission (SDT).

[0015] The received information may be received in an RRC release message from the RAN node.

[0016] The first channel may be a physical downlink shared channel (PDSCH).

[0017] Reading the paging message may include identifying a paging indication in a paging opportunity on a physical downlink control channel (PDCCH), and reading the paging message from a paging channel (PCH) on the PDSCH based on identifying the paging indication.

[0018] The received information may include at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs, and the UE may determine the position assigned to it from among the plurality of positions based on the UE's identification information.

[0019] The UE's identification information may be a numerical value, and the UE may determine the position assigned to it from among the plurality of positions based on AmodB (where A is the UE's identification information and B is the total number of UEs).

[0020] The received information may include a parameter indicating a distance in the time domain between a first position among a plurality of positions allocated for paging messages on the PDSCH and small data transmissions on the PDSCH, and at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs. The at least one parameter indicating a plurality of positions may include at least one of the total number of the plurality of positions, the number of positions per unit of the time domain, and the number of positions per unit of the frequency domain.

[0021] According to aspects of one or more embodiments, there is provided a non-transitory computer-readable recording medium having recorded thereon instructions executable by at least one processor for performing the above method.

[0022] According to aspects of one or more embodiments, there is provided an apparatus for performing an improved paging procedure on a communication network. The apparatus includes a memory storing instructions and at least one processor. The at least one processor is configured to execute instructions to receive, from a radio access network (RAN) node, information for determining a position in a first channel allocated to the apparatus for downlink data transmission while the apparatus is in radio resource control (RRC) inactive mode, transition from RRC connected mode to RRC inactive mode, read a paging message indicating the apparatus for paging, and read downlink data at a position in the first channel determined based on the received information while in RRC inactive mode.

[0023] The at least one processor may be configured to execute instructions to read downlink data based on a determination that the paging message includes information indicating that the cause of paging is small data transmission (SDT).

[0024] The received information may be received in an RRC release message from the RAN node.

[0025] The first channel may be a physical downlink shared channel (PDSCH).

[0026] The received information may include at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs, and at least one processor may be configured to execute instructions to determine, based on the identification information of the device, the position assigned thereto from among the plurality of positions.

[0027] The identification information may be a numerical value, and at least one processor may be configured to execute instructions to determine, based on AmodB (where A is the identification information of the device and B is the total number of the plurality of UEs), the position assigned thereto from among the plurality of positions.

[0028] The received information may include a parameter indicating a distance in the time domain between a paging message on the PDSCH and a first position among the plurality of positions assigned for small data transmission on the PDSCH, and at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs. The at least one parameter indicating the plurality of positions may include at least one of the total number of the plurality of positions, the number of positions per unit of the time domain, and the number of positions per unit of the frequency domain.

[0029] According to aspects of one or more embodiments, a method for performing an improved paging procedure by a RAN node is provided. The method includes generating an RRC release message including parameters for determining a location of a first channel assigned to a UE in RRC inactive mode for small data transmission; transmitting the RRC release message to the UE to transition the UE from RRC connected mode to RRC inactive mode; receiving downlink (DL) data from a core network for the UE; transmitting a paging message to the UE based on receiving the DL data; and transmitting the DL data to the UE in RRC inactive mode at a location of the first channel determined by the RAN node based on at least the parameters included in the RRC release message, based on receiving the DL data.

[0030] The first channel may be a Physical Downlink Shared Channel (PDSCH), the parameters in the RRC release message may include at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs, and the location of the first channel assigned to the UE may be determined from the plurality of positions based on AmodB, where A is a numerical identifier of the UE and B is the total number of the plurality of UEs.

[0031] Transmitting the paging message may include generating a paging message including a parameter indicating that the cause of the paging message is small data transmission.

[0032] According to aspects of one or more embodiments, a non-transitory computer-readable recording medium having instructions executable by at least one processor for performing the above-described method is provided.

Brief Description of the Drawings

[0033] The features, advantages, and significance of the exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings in which like numerals represent like elements.

[0034] FIG. 1 illustrates paging procedures in the related art.

[0035] FIG. 2 illustrates the definition of a Radio Resource Control (RRC) release message in the related art.

[0036] FIG. 3 illustrates the definition of a paging message in the related art.

[0037] FIG. 4 illustrates a flowchart of a method for performing an improved paging procedure by a User Equipment (UE) according to one or more embodiments.

[0038] FIG. 5 shows an example of the definition of an RRC release message according to one or more embodiments.

[0039] FIG. 6 shows an example of the definition of a paging message according to one or more embodiments.

[0040] FIG. 7 shows an example of a Physical Downlink Shared Channel (PDSCH) position configuration in the time and frequency domains for small data transmission in an improved paging procedure according to one or more embodiments.

[0041] FIG. 8 shows an example of a plurality of PDSCH opportunities in the time and frequency domains according to a paging message according to one or more embodiments.

[0042] FIGS. 9A and 9B illustrate an improved paging procedure for small data transmission according to one or more examples.

[0043] FIG. 10 illustrates a flowchart of a method for performing an improved paging procedure by a Radio Access Network (RAN) node according to one or more embodiments.

[0044] FIG. 11 is a diagram of components of one or more devices according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0045] The following detailed description of the embodiments refers to the accompanying drawings. The same reference numerals in different figures may identify the same or similar elements.

[0046] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit implementation to the exact forms disclosed. Modifications and variations are possible in light of the foregoing disclosure or may be gained from practice of the implementation. Further, one or more features or components of one embodiment may be integrated with or combined with those of other embodiments (or one or more features of other embodiments). Additionally, in the flowchart and operation descriptions provided below, one or more operations may be omitted, one or more operations may be added, one or more operations may be executed simultaneously (at least in part), and the order of one or more operations may be interchanged.

[0047] It will be apparent that the systems and / or methods described herein may be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual special control hardware or software code used to implement these systems and / or methods is not a limitation of the implementation. For this reason, the operations and behavior of the systems and / or methods are described herein without reference to specific software code. It is understood that software and hardware may be designed to implement the systems and / or methods based on the description herein.

[0048] Even if a particular combination of features is recited in a claim and / or disclosed in the specification, these combinations are not intended to limit the disclosure of possible implementations. In fact, many of these features may be combined in ways different from those specifically recited in the claims and / or specifically disclosed in the specification. Each of the dependent claims listed below may depend directly on only one claim, but the disclosure of possible implementations includes each dependent claim in combination with all other claims in the claim group.

[0049] None of the elements, acts, or instructions used herein should be construed as important or essential unless explicitly described. Also, as used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." If only one item is intended, the term "one" or a similar term is used. Also, as used herein, the terms "has," "have," "having," "include," "including," etc. are intended to be open-ended terms. Further, the phrase "based on" is intended to mean "at least in part based on" unless explicitly stated otherwise. Further, expressions such as "at least one of A and B" or "at least one of A or B" are understood to include only A, only B, or both A and B.

[0050] As described above, in the paging procedure of the related art, it is necessary for a user equipment (UE) to establish an RRC connection to receive data from the network. This state transition and the accompanying signaling required therefor result in high power consumption in the radio resource control (RRC) connected state, even for receiving latency, radio resource utilization, and a small amount of downlink data.

[0051] Embodiments provide a system and method for pre-configuring a position in a Physical Downlink Shared Channel (PDSCH) through which data can be sent to a UE in an RRC inactive state. As a result, the UE can receive and read small data transmissions after decoding a paging message without performing RRC setup procedures, reducing latency, signaling overhead, radio resource utilization, and UE power consumption.

[0052] FIG. 4 illustrates a flowchart of a method for performing an improved paging procedure by a UE according to one or more embodiments. Referring to FIG. 4, in operation S410, the UE receives, from a network (e.g., a base station or gNB), information indicating a PDSCH position through which data can be sent to the UE in an RRC inactive mode. In one embodiment, as illustrated in FIG. 5 and described below with reference to FIG. 5, the information may be included in an RRC release message as one or more new fields or parameters. The UE and the network may communicate over a communication network (e.g., a radio access network compliant with 3GPP standards or any other communication network).

[0053] In operation S420, the UE transitions from the RRC connected mode to the RRC inactive mode.

[0054] In operation S430, the UE checks for a paging indication in a Physical Downlink Control Channel (PDCCH). For example, a UE in the RRC inactive mode may periodically monitor a paging opportunity in the PDCCH for a paging indication. The UE may perform this monitoring according to a predetermined DRX cycle (e.g., set or implied in PDCCH-ConfigCommon).

[0055] If the UE does not identify a paging indication in the paging opportunity (No in operation S440), the UE repeats operation S430.

[0056] On the one hand, when the UE identifies a paging indication during a paging opportunity (Yes in operation S440), in operation S450, the UE reads a paging message on the PDSCH in the paging channel (PCH). For example, the UE may decode resource allocation information for the paging message from the PDCCH and identify the position (PDSCH resource block) where the indicated paging message is sent.

[0057] FIG. 6 is an example of the definition of a paging message according to an embodiment. Referring to FIG. 6, a paging message according to an embodiment further specifies whether the cause of paging is data transmission (e.g., small data transmission (SDT)). For this purpose, a paging message according to an embodiment further lists "sdt" as a possible value for the access type parameter. This is merely an example, and it is understood that one or more other embodiments are not limited thereto. That is, in one or more other embodiments, values or identifiers different from "sdt", different parameters different from the access type, and fields different from the PagingRecord may be used to signal or indicate that the cause of paging is small data transmission.

[0058] The UE may decode the paging message in operation S450 and check whether its S-TMSI (Serving Temporary Mobile Subscriber Identity) is included in the paging record (PagingRecord). If the S-TMSI is not included in the paging record, the UE may determine that the paging is not directed thereto, and the process may return to operation S430.

[0059] Furthermore, in operation S450, the UE may determine whether the cause of paging is data transmission (e.g., SDT). For example, referring to FIG. 6, the UE may check in the paging record whether the cause of SDT is specified in the access type parameter.

[0060] If the cause decoded in the paging message is not SDT (No in operation S460), the UE may execute the RRC resume procedure to re - establish the RRC connection in operation S470.

[0061] On the other hand, if the cause decoded in the paging message is SDT (Yes in operation S460), the UE may read the SDT data on the PDSCH without executing the RRC resume procedure in operation S480. That is, the UE reads the SDT data from the PDSCH while remaining in the RRC inactive state. Here, the UE uses the information received in operation S410 to determine the position of the SDT data in the PDSCH. For example, as described in more detail below with reference to FIGS. 5, 7, and 8, the information may be read from the fields of the RRC release message and used to determine the SDT position assigned to the UE in the PDSCH.

[0062] It is understood that in various embodiments, one or more operations of FIG. 4 may be omitted and / or one or more additional or different operations may be added.

[0063] FIG. 5 is an example of the definition of an RRC release message including a small data transfer paging configuration field (stdpagingconfig) according to an embodiment. Referring to FIG. 5, sdtpagingconfig includes parameters for determining the PSDSCH position for SDT data assigned to the UE. These parameters may be the information received in operation S410 of FIG. 4 and are listed and described in Table 1 below.

Table 1

[0064] It is understood that the message definition of FIG. 5 and the parameters in Table 1 are merely examples, and one or more other embodiments are not limited thereto. For example, in various other embodiments, one or more of the above parameters (and field names) may vary, one or more of the above parameters may be omitted, and one or more additional or other parameters may be included. Further, one or more of the above parameters may be optional, for example, may be omitted and / or understood as default values (e.g., defined in the standard) or by a predetermined method (e.g., using one or more previously determined and / or standard-defined values).

[0065] FIG. 7 shows an example of the PDSCH position configuration in the time and frequency domains for small data transmission in an improved paging procedure according to one or more embodiments. In particular, FIG. 7 illustrates the position configuration based on the parameters defined in the example of the RRC release message of FIG. 5.

[0066] Referring to FIGS. 5 and 7, a PDSCH opportunity is a location of the PDSCH where small data may be transmitted to a UE in RRC inactive mode. The location of the PDSCH opportunity in the time domain (e.g., the first PDSCH opportunity in a sequence (or cycle) of PDSCH opportunities following a paging message indicating small data transmission) may be defined with respect to the PCH as the number of symbols (or, in other embodiments, frames or sub-frames) from the PCH to the PDSCH opportunity. In one embodiment, the symbolstopdsch parameter may define the number of symbols from the end of the paging message to the start of the PDSCH opportunity, but it is understood that one or more other embodiments are not limited thereto. For example, according to other embodiments, the location of the PDSCH opportunity may be defined as the number of symbols from the start of the paging message to the start of the PDSCH opportunity.

[0067] The total number of PDSCH opportunities may define the number of different locations where small data may be transmitted to different UEs, respectively, in a single sequence (or cycle) following a paging message. In this regard, each PDSCH opportunity may correspond to a different UE among a predetermined set of UEs. The network (e.g., gNB or radio access network (RAN) element) and a particular UE may determine, in a predetermined manner, which PDSCH opportunity corresponds to the particular UE. For example, according to one embodiment, the PDSCH opportunity corresponding to a UE may be determined using a unique identifier of the UE (e.g., S-TMSI). In this exemplary case, the PDSCH opportunity (sequence number) corresponding to the UE may be determined by the UE and the network as "S-TMSI mod n". Here, "n" is the number of PDSCH opportunities in a single sequence (i.e., noOfPdschOccasion or noOfPdschOccasionperTDM x noOfPdschOccasionperFDM).

[0068] Furthermore, the number of PDSCH occasions in the time domain (noOfPdschOccasionperTDM) and the number of PDSCH occasions in the frequency domain (noOfPdschOccasionperFDM) define the relative placement of the total number of PDSCH occasions per sequence in the time and frequency domains. The guard between two PDSCH occasions in the time domain (guardSdtPdschOccasionTDM) defines the offset or space (e.g., number of symbols) in the time domain between sets of PDSCH occasions (as shown in Figure 7). Similarly, the guard between two PDSCH occasions in the frequency domain (guardSdtPdschOccasionFDM) defines the offset or space (e.g., number of PRBs) in the frequency domain between PDSCH occasions.

[0069] The following Table 2 provides an example of a set of values for the parameters defined in the RRC release message of Figure 5.

Table 2

[0070] In the example of Table 2, the UEs are divided into 6 groups corresponding to the total number of PDSCH occasions (noOfPdschOccasion) in one sequence. The six PDSCH occasions are divided into two sets (noOfPdschOccasionperTDM = 2) in the time domain. Figure 8 illustrates the placement of PDSCH occasions in the time and frequency domains according to the example of Table 2.

[0071] Table 3 below illustrates the mapping between the S-TMSI values for six UEs and the corresponding PDSCH positions (PDSCH occasion sequence numbers) among the total number of PDSCH opportunities assigned to the set of UEs according to the example of Table 2. In this example, the mapping is determined by "S-TMSI mod 6" (with "noOfPdschOccasion = 6"). However, one or more other embodiments are not limited to this, and it is understood that other methods for mapping or allocating UEs to PDSCH positions for small data transmission may be implemented. [Table 3]

[0072] Based on a method for mapping PDSCH position information for data transmission defined in an RRC release message and PDSCH positions (opportunities) as described above to a UE, a network (e.g., an NG-RAN node or gNB) may schedule data transmission (e.g., small data transmission) on the PDSCH in a sequence from the arrival of the first symbol and the first frequency to the arrival of the last symbol and the last frequency. Similarly, the UE can identify the PDSCH position for its data transmission in the same way. Therefore, data transmission to the UE is performed while the UE remains in the RRC inactive state, reducing the latency and signaling overhead associated with transitioning the RRC state and saving radio resources and power consumed by the RRC connected state.

[0073] Figure 9A illustrates a small data transmission improved paging procedure according to an embodiment. Referring to Figure 9A, the UE transitions from the RRC connected state to inactive using the RRC release procedure. For this purpose, an RRC release message according to one embodiment is transmitted from a RAN node (e.g., gNB) to the UE and includes information indicating (or that can be used to determine) the position of the PDSCH allocated to the UE in the RRC inactive mode for small data transmission. For example, the RRC release message may be defined to include the PDSCH opportunity for the SDT parameter in the SuspendConfig field as shown in Figure 5.

[0074] Still referring to Figure 9A, while in the inactive state, the UE wakes up periodically and monitors the PDCCH for paging indication at one paging opportunity per DRX cycle. For example, the paging opportunity may be monitored based on the paging search space defined for paging, which is included in the cell-specific configuration parameters (PDCCH-ConfigCommon) of the PDCCH.

[0075] When there is some downlink (DL) data to be transmitted to the UE in the RRC inactive mode, the user plane function (UPF) of the core network may transmit the DL user plane data to a RAN node (e.g., gNB). In other embodiments or examples, it is understood that different functions of the core network (e.g., access and mobility function (AMF)) may transmit or route the DL data to the RAN or the node serving the target UE. The UPF or core network function may not need to recognize the current RRC mode of the UE.

[0076] When receiving DL data, the RAN node may determine that the DL user plane data is small data transmission (SDT), and may trigger or initiate an improved paging procedure (or SDT paging procedure) according to one or more embodiments. For this purpose, the RAN node may send a paging indication on the paging opportunity in the PDCCH. The RAN node may encrypt the paging indication using the P-RNTI (paging radio network temporary identifier) sent in the SIB by the base station. Also, the RAN node may send a paging message configured by the RAN node on the paging channel (PCH) of the physical downlink shared channel (PDSCH) so as to indicate that the cause of paging is SDT. For example, the paging message according to one embodiment may be as defined in FIG. 6.

[0077] Subsequently, the UE may use the P-RNTI to scramble or decrypt the paging indication in the PDCCH, and may check for a paging message on the paging channel (PCH) of the physical downlink shared channel (PDSCH). Specifically, the UE decodes the paging message and checks whether its S-TMSI is included in the paging record (PagingRecord). Also, the UE checks whether the paging message indicates that the cause of paging is SDT. For example, the paging message may be as defined in FIG. 6, and the UE may check whether the cause is "sdt" in the access type.

[0078] If the UE finds its own ID (S-TMSI) in the paging record of the paging message and determines that the cause of paging is SDT, it reads downlink data from the PDSCH at the position determined from the parameters described in the RRC release message. Based on successfully reading downlink data from the PDSCH, the UE may send an acknowledgement (ACK) to the RAN node. The UE reads the downlink data and sends an acknowledgement while remaining in the RRC inactive mode. As a result, the UE can receive SDT without performing the RRC setup procedure, reducing latency, signaling, and radio resource overhead.

[0079] Figure 9A shows an example of the flow of an improved paging procedure according to an embodiment, where the serving RAN node that performs paging is the same as the last serving RAN node when the RRC release procedure was executed. However, in one or more embodiments, if the serving RAN node that performs paging is different from the serving RAN node that sends the RRC release message, there will be a failure of RAN paging as shown in Figure 9B.

[0080] Figure 9B illustrates a small data transmission improved paging procedure according to an example, where the serving RAN node and the last serving RAN node are different. Referring to Figure 9B, the last serving RAN node sends an RRC release message according to an embodiment, including information indicating (or that can be used to determine) the position of the PDSCH allocated to the UE in the RRC inactive mode for small data transmission. For example, the RRC release message may be defined to include the PDSCH opportunity for the SDT parameter in the SuspendConfig field as shown in Figure 5.

[0081] However, while in the RRC inactive mode, for example, the serving node changes for a handover procedure. As a result, paging instructions, paging messages, and small data transmissions (SDTs) initiated by the last serving RAN node cannot reach the UE. When a failure of RAN paging is determined (e.g., after a predetermined period or a predetermined timer has elapsed after the transmission of DL data without receiving an acknowledgement from the UE), the last serving RAN node may send a message to prompt the execution of the SDT paging procedure to the UE's current serving RAN node. In this case, the serving RAN node may page over the RAN notification area (RNA) as a normal procedure, but does not push SDT data with the paging message. As shown in FIG. 9B, the UE responds to the paging in the RRC resume procedure, and the serving node routes this paging response to the last serving node over the Xn interface. Subsequently, the last serving node triggers the DL data transfer to the serving node using the anchor relocation process or the anchor non-relocation process according to the embodiment.

[0082] In the anchor relocation process, the serving RAN node retrieves the UE context together with the SDT data from the last serving RAN node. In the anchor non-relocation process, the serving RAN node tunnels the SDT data from the last serving RAN node without releasing the UE context. In this case, encryption, security, and responses to the core network (e.g., 5GC) are ensured by the last serving RAN node.

[0083] Still referring to FIG. 9B, upon receiving the DL data transfer from the last serving node, the serving node responds to the UE with an RRC release with a suspend indication to keep the UE in the RRC inactive mode. The serving RAN node piggybacks the SDT data with this indication.

[0084] Accordingly, the UE reads the DL data and sends an acknowledgment to the serving RAN node. The acknowledgment is tunneled to the last serving RAN node and the core network in the case of anchor non-relocation, or sent directly to the core network in the case of anchor relocation.

[0085] If the acknowledgment is received, the SDT paging procedure is completed. If the acknowledgment is not received or a NACK is received, the process is repeated by the RAN.

[0086] FIG. 10 illustrates a flowchart of a method for performing a paging procedure improved by a RAN node according to one or more embodiments. Referring to FIG. 10, a RAN node (e.g., a gNB or a base station of any type of RAN) configures an RRC release message including parameters for indicating the position of a PDSCH allocated to a UE in RRC inactive mode for small data transmission in operation S1010. An RRC release message according to one embodiment may be as defined in FIG. 5.

[0087] In operation S1020, the RAN node sends an RRC release message to the UE to transition the UE from RRC connected to RRC inactive.

[0088] In operation S1030, the RAN node receives downlink (DL) user plane data for the UE from the core network. For example, the RAN node may receive SDT data from a core network function (e.g., UPF, AMF, etc.).

[0089] Based on receiving the DL data, in operation S1040, the RAN node transmits a paging indication on the paging occasion in the PDCCH and transmits a paging message on the PCH of the PDSCH. Here, the RAN node may determine that the DL data is SDT data, and based on this determination, may also configure a paging message to indicate that the cause of paging is SDT. For example, the paging message may be defined as shown in FIG. 6.

[0090] In operation S1050, at the position of the PDSCH allocated to the UE, the RAN node transmits DL data (e.g., SDT data) to the UE. For example, the RAN node may determine the position based on the parameters included in the RRC release message and the unique identifier of the UE (e.g., S-TMSI) as described above. When there is some downlink (DL) data to be transmitted to a UE in the RRC inactive mode, the user plane function (UPF) of the core network may transmit the DL user plane data to the RAN node (e.g., gNB). In other embodiments or examples, it is understood that different functions of the core network (e.g., access and mobility function (AMF)) may transmit or route the DL data to the RAN or the node serving the target UE. The UPF or the core network function may not need to recognize the current RRC mode of the UE.

[0091] In operation S1060, regarding the transmitted SDT data, the RAN node receives a confirmation from the UE. Operations 1040 to 1060 are executed while the UE remains in the RRC inactive state.

[0092] If the RAN node does not receive a confirmation message within a predetermined period, in order to trigger the SDT paging process as described above with reference to FIG. 9B, a message may be transmitted to another RAN node.

[0093] In various embodiments, one or more of the operations in FIG. 10 may be omitted and / or one or more additional or different operations may be added.

[0094] FIG. 11 is a diagram of components of one or more devices according to an example. Device 1100 may correspond to any of the previously described devices (e.g., a UE, a base station, a RAN node, a core network device implementing core network functions).

[0095] Referring to FIG. 11, device 1100 may include a bus 1110, a processor 1120, a memory 1130, a storage component 1140, and a communication interface 1150. It is understood that one or more of the components may be omitted and / or one or more additional components may be included.

[0096] Bus 1110 includes components that enable communication between components of device 1100. Processor 1120 is implemented in hardware, firmware, or a combination of hardware and software. Processor 1120 is a central processing unit (CPU), a graphics processing unit (GPU), an acceleration processing unit (APU), a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or another type of processing component. Processor 1120 includes one or more processors programmable to execute functions.

[0097] Memory 1130 includes a random access memory (RAM), a read-only memory (ROM), and / or other types of dynamic or static storage devices (e.g., flash memory, magnetic memory, and / or optical memory) that store information and / or instructions for use by processor 1120.

[0098] The storage component 1140 stores information and / or software related to the operation and use of the device 1100. For example, the storage component 1140, together with the corresponding drive, may include a hard disk (e.g., magnetic disk, optical disk, magneto-optical disk, and / or solid state disk), a compact disc (CD), a digital versatile disc (DVD), a floppy disk, a cartridge, a magnetic tape, and / or other types of non-transitory computer-readable media.

[0099] The communication interface 1150 includes a component such as a transceiver (e.g., a transceiver and / or a split receiver and transmitter) that enables the device 900 to communicate with other devices via a wired connection, a wireless connection, or a combination of wired and wireless connections. The communication interface 1150 may enable the device 1100 to receive information from other devices and / or provide information to other devices. For example, the communication interface 1150 may include an Ethernet interface, an optical interface, a coaxial interface, an infrared interface, a radio frequency (RF) interface, a universal serial bus (USB) interface, a Wi-Fi interface, a cellular network interface, etc.

[0100] The device 1100 may perform one or more of the processes or functions described herein. The device 1100 may perform operations based on a processor 1120 that executes software instructions stored by a non-transitory computer-readable medium such as the memory 1130 and / or the storage component 1140. The computer-readable medium is defined herein as a non-transitory memory device. The memory device includes a memory space within a single physical storage device or a memory space distributed across multiple physical storage devices.

[0101] Software instructions may be read into memory 1130 and / or storage component 1140 from other computer-readable media or other devices via communication interface 1150. When executed, the software instructions stored in memory 1130 and / or storage component 1140 may cause processor 1120 to execute one or more of the processes described herein.

[0102] In addition or alternatively, instead of software instructions, or in combination with software instructions, wired circuits may be used to perform one or more of the processes described herein. Thus, the embodiments described herein are not limited to a particular combination of hardware circuitry and software.

[0103] The above disclosure provides illustration and description, but is not intended to be exhaustive or to limit implementation to the exact form disclosed. Modifications and variations are possible in light of the above disclosure, or may be obtained from practice of the implementation.

[0104] Some embodiments may relate to systems, methods, and / or computer-readable media at any possible level of technical detail of integration. Further, one or more of the above-described components may be implemented as instructions stored on a computer-readable medium and executable by at least one processor (and / or may include at least one processor). The computer-readable medium may include a computer-readable non-transitory storage medium (or media) storing computer-readable program instructions for causing a processor to execute operations.

[0105] A computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction-executing device. A computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital versatile discs (DVDs), memory sticks, floppy disks, punch cards, mechanically encoded devices such as a raised structure in a groove in which instructions are recorded, and any suitable combination thereof. As used herein, a computer-readable storage medium is not to be construed as being a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0106] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to respective computing / processing devices, or can be downloaded from an external computer or an external storage device via a network such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each respective computing / processing device.

[0107] The computer-readable program code / instructions for performing the operation may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data for an integrated circuit, or source code or object code written in any combination of one or more programming languages including object-oriented programming languages such as Smalltalk, C++, and procedural programming languages such as the "C" programming language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer as a stand-alone software package, partially on the user's computer, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, for example, an electronic circuit including a programmable logic circuit, an FPGA (field-programmable gate array), or a programmable logic array (PLA) may execute the computer-readable program instructions by utilizing the state information of the computer-readable program instructions to personalize the electronic circuit for performing the aspect or operation.

[0108] These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram (one or more blocks). These computer-readable program instructions may be stored in a computer-readable storage medium that, when containing instructions that implement aspects of the functions / acts specified in the flowchart and / or block diagram (one or more blocks), causes a computer, programmable data processing apparatus, and / or other device to function in a particular manner.

[0109] The computer-readable program instructions may be loaded onto a computer, other programmable data processing apparatus, or other device, such that a series of operational steps are performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, thereby causing instructions executing on the computer, other programmable apparatus, or other device to implement the functions / acts specified in the flowchart and / or block diagram (one or more blocks).

[0110] The illustrated flowcharts and block diagrams exemplify the architecture, functionality, and operation of possible implementations of systems, methods, and computer-readable media according to various embodiments. Here, each block in a flowchart or block diagram may represent a module, segment, or portion of instructions that includes one or more executable instructions for implementing a particular logical function. The methods, computer systems, and computer-readable media may include additional blocks, fewer blocks, different blocks, or differently arranged blocks compared to those shown in the figures. In some alternative implementations, the functions represented in the blocks may occur out of the order shown in the figures. For example, two blocks shown in succession may actually be executed simultaneously or substantially simultaneously, depending on the functions involved, or the blocks may be executed in the reverse order. Note that each block of the illustrated examples of block diagrams and / or flowcharts, and combinations of blocks in the illustrated examples of block diagrams and / or flowcharts, may be implemented by a system based on dedicated hardware for performing a particular function or action, or by a combination of dedicated hardware and computer instructions.

[0111] It is evident that the systems and / or methods described herein may be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit the implementation. Thus, the operation and behavior of the systems and / or methods are described herein without reference to specific software code. This is understood to mean that software and hardware may be designed based on the description herein to implement the systems and / or methods.

Claims

1. A method for performing an improved paging procedure by a user equipment (UE), comprising: receiving, from a radio access network (RAN) node, information for determining a position in a first channel assigned to the UE for downlink data transmission while the UE is in a radio resource control (RRC) inactive mode; transitioning from an RRC connected mode to the RRC inactive mode; reading a paging message indicating the UE for paging; reading downlink data at the position in the first channel determined by the UE based on the received information while the UE is in the RRC inactive mode; A method comprising the above.

2. The method according to claim 1, wherein reading the downlink data comprises reading the downlink data at the position in the first channel determined by the UE based on the received information, based on determining that the paging message includes information indicating that the cause of the paging is small data transmission (SDT).

3. The method according to claim 1, wherein the received information is received in an RRC release message from the RAN node.

4. The method according to claim 1, wherein the first channel is a physical downlink shared channel (PDSCH).

5. Reading the paging message comprises: identifying a paging indication in a paging opportunity on a physical downlink control channel (PDCCH); reading the paging message from a paging channel (PCH) on the PDSCH based on identifying the paging indication; The method according to claim 4, comprising the above.

6. The received information comprises at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs; The UE determines the position assigned to it from among the plurality of positions based on the identification information of the UE. The method according to claim 4.

7. The identification information of the UE is a numerical value; The UE determines the position assigned to it from among the plurality of positions based on A mod B (where A is the identification information of the UE and B is the total number of the plurality of UEs). The method according to claim 6.

8. The received information is a parameter indicating a distance in a time domain between a paging message on the PDSCH and a first position among a plurality of positions assigned for small data transmission on the PDSCH, at least one parameter indicating the plurality of positions in the PDSCH, each corresponding to a plurality of UEs, comprising the at least one parameter indicating the plurality of positions comprises at least one of the total number of the plurality of positions, the number of positions per unit of the time domain, and the number of positions per unit of the frequency domain. The method according to claim 4.

9. A non-transitory computer-readable recording medium having recorded thereon instructions executable by at least one processor for performing the method according to claim 1.

10. An apparatus for performing an improved paging procedure on a communication network, a memory for storing instructions, receiving, from a radio access network (RAN) node, information for determining a position in a first channel assigned to the apparatus for downlink data transmission while the apparatus is in a radio resource control (RRC) inactive mode, transitioning from an RRC connected mode to the RRC inactive mode, reading a paging message indicating the apparatus for paging, reading downlink data at the position in the first channel determined based on the received information while the apparatus is in the RRC inactive mode, at least one processor configured to execute the instructions to perform as such, an apparatus comprising.

11. The apparatus according to claim 10, wherein the at least one processor is configured to execute the instructions to read the downlink data based on a determination that the paging message includes information indicating that a cause of the paging is small data transmission (SDT).

12. The apparatus according to claim 10, wherein the received information is received in an RRC release message from the RAN node.

13. The apparatus according to claim 10, wherein the first channel is a physical downlink shared channel (PDSCH).

14. The received information includes at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs. The at least one processor is configured to execute the instructions to determine, based on the identification information of the device, the position assigned thereto from among the plurality of positions. The device according to claim 13.

15. The identification information is a numerical value. The at least one processor is configured to execute the instructions to determine, based on A mod B (where A is the identification information of the device and B is the total number of the plurality of UEs), the position assigned thereto from among the plurality of positions. The device according to claim 14.

16. The received information includes a parameter indicating a distance in the time domain between the paging message on the PDSCH and a first position among a plurality of positions assigned for small data transmission on the PDSCH, and at least one parameter indicating the plurality of positions in the PDSCH, each corresponding to a plurality of UEs. and includes The at least one parameter indicating the plurality of positions includes at least one of the total number of the plurality of positions, the number of positions per unit of the time domain, and the number of positions per unit of the frequency domain. The device according to claim 13.

17. A method for performing an improved paging procedure by a RAN node, the method comprising: generating an RRC release message comprising a parameter for determining a position of a first channel assigned to a UE in RRC inactive mode for small data transmission; transmitting the RRC release message to the UE to transition the UE from RRC connected mode to the RRC inactive mode; receiving downlink (DL) data from a core network for the UE; transmitting a paging message to the UE based on receiving the DL data; and transmitting the DL data to the UE in the RRC inactive mode at the position of the first channel determined by the RAN node based on at least the parameter included in the RRC release message based on receiving the DL data. A method comprising.

18. The first channel is a Physical Downlink Shared Channel (PDSCH), the parameters in the RRC release message include at least one parameter indicating a plurality of positions in the PDSCH, each corresponding to a plurality of UEs, the position of the first channel assigned to the UE is determined from the plurality of positions based on A mod B (where A is the numerical identifier of the UE and B is the total number of the plurality of UEs), The method according to claim 17.

19. The method according to claim 17, wherein transmitting the paging message comprises generating the paging message comprising a parameter indicating that the cause of the paging message is small data transmission.

20. A non-transitory computer-readable recording medium having recorded thereon instructions executable by at least one processor for performing the method according to claim 17.

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