Connection management for small data transmission and non-small data transmission

Abstract

A method of wireless communication performed by a first network element includes receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode. The method also includes receiving, from a second network element, an indication of arrival at the second network element of at least one of non-SDT downlink (DL) data or a non-SDT DL signal scheduled for the UE. The method further includes transmitting, based on the indication, a random access communication to the UE to: move the UE into a connected mode; or keeping the UE in the inactive mode.

Description

Background Art

[0001] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). A wireless multiple-access communication system may include multiple base stations (BSs), each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0002] In order to meet the growing demand for extended mobile broadband connections, wireless communication technology is evolving from long term evolution (LTE) technology to next generation new radio (NR) technology, which may be referred to as the fifth generation (5G). For example, NR is designed to provide lower latency, higher bandwidth or higher throughput, and higher reliability compared to LTE. NR is designed to operate over a wide range of frequency bands, such as from low frequency bands below about 1 gigahertz (GHz) and from medium frequency bands from about 1 GHz to about 6 GHz, to high frequency bands, such as mmWave bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed spectrum and shared spectrum. Spectrum sharing enables operators to have the opportunity to aggregate spectrum to dynamically support high bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0003] A UE operating in an LTE-enabled and / or NR-enabled network may operate in one of a plurality of connection modes or states to save power and network resources. For example, if the UE is not scheduled to receive downlink (DL) communications or to send uplink (UL) communications, the UE may be moved to an idle mode or an inactive mode. The network may be based on a request from the UE or in response to data or signaling being scheduled for sending to the UE to move the UE back to a connection mode for receiving data and / or signals (e.g., reference signals). Moving the UE back to the connection mode may involve the transmission of various random access and / or connection management communications between the UE and / or one or more network nodes. However, a UE in an inactive state may allow some relatively small and infrequent communications (e.g., data or signals) to be sent without first experiencing a state transition to a connection mode. In some aspects, the network may have performed a handover process before receiving a small data transmission (SDT) communication from the UE, so that the current serving network node does not have context information for receiving and / or decoding communications from the UE. Summary of the invention

[0004] The following summarizes some aspects of the present disclosure to provide a basic understanding of the technology discussed. This summary is not an exhaustive overview of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to delineate the scope of any or all aspects of the present disclosure. The sole purpose of this summary is to present some concepts of one or more aspects of the present disclosure in a summarized form as a prelude to more specific embodiments presented later.

[0005] A method of wireless communication performed by a first network element, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving an indication of arrival of at least one of non-SDT downlink (DL) data or a non-SDT DL signal scheduled for the UE at the second network element from a second network element; and sending a random access communication to the UE based on the indication to: move the UE into a connected mode; or keep the UE in the inactive mode.

[0006] A method of wireless communication performed by a first network unit, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving at least one of non-SDT downlink (DL) data or non-SDT DL signals scheduled for the UE; and in response to receiving the at least one of the non-SDT DL data or the non-SDT DL signal, sending to a second network unit: an indication of the non-SDT DL data or the non-SDT DL signal received at the first network unit; and UE context information associated with the UE.

[0007] A method of wireless communication performed by a user equipment (UE), the method comprising: while in an inactive mode, sending a first random access communication to move the UE into a connected mode, wherein the first random access communication includes at least one of uplink (UL) small data transmission (SDT) data or a UL SDT signal; while in the inactive mode, receiving a second random access communication from a first network element to keep the UE in the inactive mode, wherein the second random access communication includes an indication that at least one of DL non-SDT data or a DL non-SDT signal is scheduled for communication to the UE; and sending a third random access communication based on the indication to move the UE into the connected mode.

[0008] After reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying drawings, other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art. Although the various features of the present invention may be discussed with respect to certain embodiments and drawings below, all embodiments of the present invention may include one or more of the advantageous features discussed herein. In other words, although one or more embodiments may be discussed as having certain advantageous features, one or more of these features may also be used according to the various embodiments of the present invention discussed herein. In a similar manner, although the exemplary embodiments may be discussed below as device, system, or method embodiments, it should be understood that these exemplary embodiments may be implemented in various devices, systems, and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A A wireless communication network according to some aspects of the present disclosure is illustrated.

[0010] Figure 1B An example disaggregated base station architecture is illustrated in accordance with some aspects of the present disclosure.

[0011] Figure 2 A radio frame structure according to some aspects of the present disclosure is illustrated.

[0012] Figure 3A A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0013] Figure 3B A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0014] Figure 3C A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0015] Figure 3D A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0016] Figure 3E A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0017] Figure 3F A method for connection management for small data transmission and non-small data transmission according to some aspects of the present disclosure is illustrated.

[0018] Figure 4 is a block diagram of a user equipment (UE) according to some aspects of the present disclosure.

[0019] Figure 5 is a block diagram of an exemplary base station (BS) according to some aspects of the present disclosure.

[0020] Figure 6 is a flow chart of a communication method according to some aspects of the present disclosure.

[0021] Figure 7 is a flow chart of a communication method according to some aspects of the present disclosure.

[0022] Figure 8 is a flow chart of a communication method according to some aspects of the present disclosure. DETAILED DESCRIPTION

[0023] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. In order to provide a comprehensive understanding of the various concepts, the specific embodiments include specific details. However, it is apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, in order to avoid obscuring such concepts, well-known structures and components are shown in block diagram form.

[0024] The present disclosure as a whole relates to wireless communication systems, which are also referred to as wireless communication networks. In various embodiments, each technology and device can be used for wireless communication networks, such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, global mobile communication systems (GSM) networks, fifth generation (5G) or new radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" can be used interchangeably.

[0025] OFDMA network can implement radio technology such as Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM, etc. UTRA, E-UTRA and GSM are part of Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS using E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between telecommunication association groups with the goal of defining globally applicable third generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP plan to improve UMTS mobile phone standards. 3GPP may define specifications for next generation mobile networks, mobile systems, and mobile devices. The present disclosure relates to the evolution from LTE, 4G, 5G, NR and beyond wireless technologies, where access to the wireless spectrum is shared between networks using a range of new and different radio access technologies or radio air interfaces.

[0026] Specifically, 5G networks consider various deployments, various spectrums, and various services and devices that can be implemented using a unified air interface based on OFDM. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to (1) ultra-high density (e.g., about 1M nodes / km) 2 (1) provide coverage for the massive Internet of Things (IoT) with ultra-low complexity (e.g., on the order of tens of bits / second), ultra-low energy (e.g., on the order of 10+ years of battery life), and deep coverage with the ability to reach challenging locations; (2) provide coverage including mission-critical control with strong security to protect sensitive personal, financial, or classified information, ultra-high reliability (e.g., on the order of 99.9999% reliability), ultra-low latency (e.g., on the order of 1 millisecond), and for users with extensive mobility or lack of mobility; and (3) provide coverage with enhanced mobile broadband (including extremely high capacity (e.g., on the order of 10Tbps / km 2 ), extremely high data rates (e.g., multi-Gbps rates, 100+Mbps user experience rates), and deep awareness coverage with advanced discovery and optimization.

[0027] 5G NR can be implemented using an optimized OFDM-based waveform with scalable parameter sets and transmission time intervals (TTIs); with a common, flexible framework to efficiently multiplex services and features using dynamic low-latency time division duplex (TDD) / frequency division duplex (FDD) designs; and with advanced wireless technologies such as massive multiple-input multiple-output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel decoding, and device-centric mobility. The scalability of parameter sets in 5G NR and the scaling of subcarrier spacing can efficiently address various services operating across different spectrums and different deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD / TDD implementations, the subcarrier spacing may appear at 15kHz on bandwidths (BW) such as 5MHz, 10MHz, 20MHz, etc. For other various outdoor and small cell coverage deployments of TDD greater than 3GHz, the subcarrier spacing may appear at 30kHz on 80MHz / 100MHz BW. For various other indoor broadband implementations, using TDD on the unlicensed portion of the 5 GHz band, subcarrier spacing may occur at 60 kHz over 160 MHz BW. Finally, for various deployments transmitting with the mmWave component at 28 GHz TDD, subcarrier spacing may occur at 120 kHz over 500 MHz BW.

[0028] 5G NR's scalable parameter sets facilitate scalable TTIs for different latency and quality of service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmission to start on symbol boundaries. 5G NR also envisions a self-contained integrated subframe design with uplink / downlink scheduling information, data, and acknowledgment in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, and supports adaptive uplink / downlink that can be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet current communication needs.

[0029] The various other aspects and features of the present disclosure are further described below. It should be apparent that the teachings herein can be embodied in various forms, and any specific structure, function, or both disclosed herein are merely representative and not restrictive. Based on the teachings herein, it should be understood by those of ordinary skill in the art that the aspects disclosed herein can be implemented independently of any other aspects, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement a device or practice a method. In addition, such a device can be implemented or such a method can be practiced using other structures, functionality, or structures and functionality other than or different from one or more of the aspects set forth herein. For example, the method can be implemented as a part of a system, device, device, and / or as an instruction stored on a computer-readable medium for execution on a processor or computer. In addition, one aspect can include at least one element of a claim.

[0030] As described above, the UE may be configured to transition to and from multiple connection modes or states. In this regard, if the UE is not scheduled to receive and / or send communications within a time period, the network may cause the UE to transition to an idle state or an inactive state. Moving the UE to an idle state or an inactive state may save power and network resources. When the network receives data or signals in a buffer to send to the UE, the network may send one or more paging messages to initiate the transition of the UE to a connection mode. The mechanism for transitioning the UE to different connection modes or states may be referred to as connection management. The protocol used by the connection management mechanism may be referred to as a random access procedure or protocol. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE may send a random access preamble, and the network may respond with a random access response. A random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI), and / or a backoff indicator. Upon receiving the random access response, the UE may send a connection request to the BS and the BS may respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, RAR, connection request, and connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, in which the UE may send a random access preamble and a connection request in a single transmission, and the BS may respond by sending a random access response and a connection response in a single transmission.

[0031] In some instances, the UE and / or the network may be configured to convey some small and / or infrequent communications when the UE is in an inactive mode, so that the UE can receive or send the communication before transitioning to a connected mode. The communication allowed may be referred to as a small data transmission (SDT) communication. SDT communications may include data and / or signals. SDT communications may include UL communications and / or DL ​​communications. In a two-step RACH process, if the UL receives UL SDT data and / or SDT UL signals in a buffer, the UE may send random access communications including SDT data and / or SDT signals to a receiving BS or network node. In some aspects, the random access communication may include a connection request message. In some aspects, the connection request message may be an RRC recovery request message or include an RRC recovery request message. On the other hand, the random access communication may include a RACH preamble and an RRC recovery request message.

[0032] In some aspects, the receiving network node may not have a UE context for receiving, processing and / or forwarding UL SDT transmission. For example, the UE context may be stored or otherwise available at the second network node. In some aspects, the second network node may be the last serving network node. In other aspects, the second network node may be an anchor network node. The first network node or the current serving network node may send a request for the UE context to the second network node. In some aspects, the second network node may decide not to send a complete UE context to the first network node that receives UL SDT communication from the UE. For example, the second network node may send only a portion of the UE context to the first network node. The first network node may send UL SDT data and / or signals to the second network node. The second network node may forward UL SDT data and / or signals to an access and mobility management function (AMF) node and / or a user plane function (UPF) node. In some instances, when the UE is still in an inactive mode, the UE and the network may perform additional UL and / or DL ​​SDT communications.

[0033] In some instances, the UE and / or network node may receive non-SDT data and / or signaling in a buffer. For example, a second network node may receive DL data on a buffer of a radio bearer that is not enabled for SDT communication. In some instances, the SDT data may remain in the buffer unless and until the network and / or UE initiates a second random access procedure. For example, if the network detects that the SDT communication has been completed, the UE may receive a release message with a pause configuration indication. The network may then send a paging message to initiate a second random access procedure to move the UE into connected mode.

[0034] The present disclosure describes methods, systems, and devices for connection management during SDT transmission and non-SDT transmission. In some aspects, a first network node receives UL SDT data and / or signals from a UE and forwards the UL SDT data and / or signals to at least one of an AMF or a UPF. In some aspects, the first network node may also communicate DL SDT data and / or signals with the UE. The first network node may receive non-SDT data and / or signals for communicating to the UE. For example, the first network node may receive non-SDT data and / or signals in a buffer. In some aspects, the buffer may be associated with a radio bearer for which SDT data is not enabled. According to one aspect of the present disclosure, a first network node may send an indication of non-SDT data and / or signals to a second network node communicating with the UE. In some aspects, sending the indication may include: sending a retrieval UE context response message to the second network node, wherein the retrieval UE context response message indicates the arrival of non-SDT data and / or signals in the buffer. In some aspects, the retrieval UE context response message includes or indicates at least a portion of the UE context. In some aspects, the second node may be referred to as a receiving node or a current serving node. The first node may be referred to as the last serving node or anchor node. Based on receiving an indication of non-SDT data and / or signals, the second node may send a random access communication to the UE to move the UE into a connected mode. Once the UE has entered the connected mode, the UE may receive non-SDT data and / or signals. On the other hand, the network may instead cause the UE to suspend or terminate the random access process in an accelerated manner. For example, the first network node may send a release message to the second network node in response to receiving non-SDT data and / or signals in a buffer. The second network node may forward the release message to the UE so that the UE remains in an inactive state or mode. In some aspects, the release message may include an indication that DL non-SDT data and / or signaling is scheduled for transmission to the UE. In some aspects, based on receiving the release message, the UE may send a random access message to initiate a random access process and move into a connected mode.

[0035] Each aspect of the present disclosure provides several advantages. For example, if the network receives DL data and / or signaling for sending to the UE during the SDT communication process initiated by the mobile station, the network can accelerate the state change of the UE to the connection mode so that the UE can receive non-SDT data and / or signaling. On the other hand, releasing the UE to suspend or stop the random access process and indicating the arrival of non-SDT data can allow the UE to initiate another random access process to receive non-SDT data. Therefore, the delay associated with conveying non-SDT communication, as well as power consumption, can be reduced. On the other hand, the UE can adjust its protocol for future SDT communication based on the indication of non-SDT data and / or signaling. For example, if the network and / or UE experience multiple interruptions of the random access-based SDT communication process due to the arrival of non-SDT data and / or signaling, the UE can apply a preference for transitioning to a connection state for sending SDT data and / or signals. In this way, the network and / or UE can make more adaptive decisions for connection management to handle SDT and / or non-SDT communications. Therefore, network resources can be used more efficiently and the user experience can be improved.

[0036] Figure 1A A wireless communication network 100 according to some aspects of the present disclosure is illustrated. The network 100 may be a 5G network. The network 100 includes several base stations (BSs) 105 (respectively labeled 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. The BS 105 may be a station that communicates with the UE 115, and may also be referred to as an evolved Node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the particular geographic coverage area of ​​the BS 105 and / or the BS subsystem serving the coverage area, depending on the context in which the term is used.

[0037] BS105 may provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as pico cells) will generally cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as femto cells) will generally also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs associated with the femto cells (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS, or a home BS. In Figure 1A In the example shown, BS105d and 105e may be conventional macro BSs, while BS105a-105c may be macro BSs with one of three-dimensional (3D), full-dimensional (FD) or massive MIMO capabilities. BS105a to 105c may utilize their higher-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. BS105f may be a small cell BS, which may be a home node or a portable access point. BS105 may support one or more (e.g., two, three, four, etc.) cells.

[0038] Network 100 may support synchronous operation or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

[0039] UE 115 is dispersed throughout the wireless network 100, and each UE 115 can be stationary or mobile. UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, etc. UE 115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc. In one aspect, UE 115 may be a device including a universal integrated circuit card (UICC). On the other hand, UE may be a device that does not include a UICC. In some aspects, UE 115 that does not include a UICC may also be referred to as an IoT device or an Internet of Everything (IoE) device. UE 115a-115d is an example of a mobile smart phone type device that accesses the network 100. UE 115 may also be a machine that is specifically configured for connected communications (including machine type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc.). UE 115e-115h are examples of various machines configured for communication to access network 100. UE 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication to access network 100. UE 115 may be able to communicate with any type of BS (whether macro BS, small cell, etc.). Figure 1A In the present invention, a lightning bolt (e.g., a communication link) indicates a wireless transmission between a UE 115 and a serving BS 105 (which is a BS designated to serve the UE 115 on a downlink (DL) and / or uplink (UL), a desired transmission between BSs 105, a backhaul transmission between BSs, or a sidelink transmission between UEs 115.

[0040] In operation, BSs 105a-105c use 3D beamforming and cooperative spatial techniques such as coordinated multipoint (CoMP) or multiple connections to serve UEs 115a and 115b. Macro BS 105d may perform backhaul communications with BSs 105a to 105c and small cell BS 105f. Macro BS 105d may also transmit multicast services that UEs 115c and 115d subscribe to and receive. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

[0041] The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., which may be examples of gNBs or access node controllers (ANCs)) may interface with the core network via a backhaul link (e.g., NG-C, NG-U, etc.) and may perform radio configuration and scheduling for communications with the UE 115. In various examples, the BSs 105 may communicate with each other directly or indirectly (e.g., via a core network) via a backhaul link (e.g., X1, X2, etc.), which may be a wired communication link or a wireless communication link.

[0042] The network 100 may also support mission-critical communications using ultra-reliable and redundant links for mission-critical devices such as UE 115e, which may be a drone. The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and links from small cell BS 105f. Other machine-type devices such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device) may communicate directly with BSs such as small cell BS 105f and macro BS 105e through the network 100, or communicate through the network in a multi-step configuration by communicating with another user device such as UE 115f that communicates temperature measurement information to a smart meter (UE 115g), which then reports to the network through the small cell BS 105f, which relays its information to the network. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD / FDD communications, such as vehicle-to-vehicle (V2V), vehicle-to-everything (V2X), cellular V2X (C-V2X) communications between UE 115i, 115j or 115k and other UEs 115, and / or vehicle-to-infrastructure (V2I) communications between UE 115i, 115j or 115k and BS 105.

[0043] In some implementations, the network 100 utilizes an OFDM-based waveform for communication. An OFDM-based system may divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, frequency bins, etc. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system BW. The system BW may also be divided into subbands. In other instances, the subcarrier spacing and / or the duration of the TTI may be scalable.

[0044] In some aspects, BS105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS105 to UE 115, and UL refers to the transmission direction from UE 115 to BS105. The communication may be in the form of a radio frame. A radio frame may be divided into a plurality of subframes or time slots, for example, about 10. Each time slot may also be divided into micro-time slots. In FDD mode, simultaneous UL transmission and DL transmission may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In TDD mode, UL transmission and DL transmission occur in different time periods using the same frequency band. For example, a subframe subset (e.g., a DL subframe) in a radio frame may be used for DL ​​transmission, and another subframe subset (e.g., an UL subframe) in a radio frame may be used for UL transmission.

[0045] DL subframes and UL subframes may also be divided into several zones. For example, each DL subframe or UL subframe may have a predefined zone for the transmission of reference signals, control information, and data. Reference signals are predetermined signals that facilitate communication between BS105 and UE 115. For example, a reference signal may have a specific pilot pattern or structure, wherein a pilot tone may span an operational BW or frequency band, and each pilot tone is located at a predefined time and a predefined frequency. For example, BS105 may send a cell-specific reference signal (CRS) and / or a channel state information-reference signal (CSI-RS) to enable UE 115 to estimate a DL channel. Similarly, UE 115 may send a sounding reference signal (SRS) to enable BS105 to estimate an UL channel. Control information may include resource assignments and protocol control. Data may include protocol data and / or operational data. In some aspects, BS105 and UE115 may communicate using self-contained subframes. Self-contained subframes may include a portion for DL ​​communication and a portion for UL communication. A self-contained subframe may be DL-centric or UL-centric. A DL-centric subframe may include a DL communication duration that is longer than a UL communication duration. A UL-centric subframe may include a UL communication duration that is longer than a UL communication duration.

[0046] In some aspects, the network 100 may be an NR network deployed on a licensed spectrum. The BS 105 may send synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BS 105 may broadcast system information associated with the network 100 (e.g., including a master information block (MIB), remaining system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some cases, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) over a physical broadcast channel (PBCH), and may broadcast the RMSI and / or OSI over a physical downlink shared channel (PDSCH).

[0047] In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from the BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identification value. The UE 115 may then receive the SSS. The SSS may enable radio frame synchronization and may provide a cell identification value that may be combined with the physical layer identification value to identify a cell. The PSS and SSS may be located in the center portion of a carrier or at any suitable frequency within a carrier.

[0048] After receiving the PSS and SSS, the UE 115 may receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, the UE 115 may receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource sets (CORESET) for physical downlink control channel (PDCCH) monitoring, physical UL control channel (PUCCH), physical UL shared channel (PUSCH), power control, and SRS.

[0049] After obtaining the MIB, RMSI and / or OSI, the UE 115 may perform a random access procedure to establish a connection with the BS 105. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 115 may send a random access preamble, and the BS 105 may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI), and / or a backoff indicator. Upon receiving the random access response, the UE 115 may send a connection request to the BS 105 and the BS 105 may respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 115 may send a random access preamble and a connection request in a single transmission, and the BS 105 may respond by sending a random access response and a connection response in a single transmission.

[0050] After the connection is established, the UE 115 and the BS 105 may enter a normal operation phase in which operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL communication and / or DL ​​communication. The BS 105 may send an UL scheduling grant and / or a DL scheduling grant to the UE 115 via the PDCCH. The scheduling grant may be sent in the form of DL control information (DCI). The BS 105 may send a DL communication signal (e.g., carrying data) to the UE 115 via the PDSCH according to the DL scheduling grant. The UE 115 may send an UL communication signal to the BS 105 via the PUSCH and / or the PUCCH according to the UL scheduling grant.

[0051] In some aspects, BS105 may communicate with UE 115 using hybrid automatic repeat request (HARQ) technology to improve communication reliability, for example, to provide ultra-reliable low-latency communication (URLLC) services. BS105 may schedule UE 115 for PDSCH communication by sending DL grants in PDCCH. BS105 may send DL data packets to UE 115 according to the scheduling in PDSCH. DL data packets may be sent in the form of transport blocks (TBs). If UE 115 successfully receives the DL data packet, UE 115 may send a HARQ confirmation (ACK) to BS105. Conversely, if UE 115 fails to successfully receive the DL transmission, UE 115 may send a HARQ negative confirmation (NACK) to BS105. Upon receiving a HARQ NACK from UE 115, BS105 may retransmit the DL data packet to UE 115. The retransmission may include a decoded version of the DL data that is the same as the initial transmission. Alternatively, the retransmission may include a different decoded version of the DL data than the initial transmission. The UE 115 may apply soft combining to combine the coded data received from the initial transmission and the retransmission for decoding. The BS 105 and the UE 115 may also apply HARQ to UL communications using a mechanism substantially similar to DL HARQ.

[0052] In some aspects, the network 100 may operate on a system BW or a component carrier (CC) BW. The network 100 may divide the system BW into multiple BWPs (e.g., parts). The BS 105 may dynamically assign the UE 115 to operate on a specific BWP (e.g., a specific part of the system BW). The assigned BWP may be referred to as an active BWP. The UE 115 may monitor the active BWP to find signaling information from the BS 105. The BS 105 may schedule the UE 115 to perform UL communication or DL ​​communication in the active BWP. In some aspects, the BS 105 may assign a pair of BWPs within the CC to the UE 115 for UL communication and DL communication. For example, the BWP pair may include a BWP for UL communication and a BWP for DL ​​communication.

[0053] In some aspects, network 100 may operate on a shared channel, which may include a shared frequency band or an unlicensed frequency band. For example, network 100 may be an NR unlicensed (NR-U) network. BS105 and UE 115 may be operated by multiple network operation entities. In order to avoid conflicts, BS105 and UE 115 may use a listen-before-talk (LBT) procedure to monitor transmission opportunities (TXOPs) in a shared channel. For example, a transmitting node (e.g., BS105 or UE 115) may perform LBT before transmitting in a channel. When LBT passes, the transmitting node may continue to transmit. When LBT fails, the transmitting node may prohibit transmitting in the channel. In one example, LBT may be based on energy detection. For example, when the signal energy measured from the channel is lower than a threshold, the LBT result is passed. Conversely, when the signal energy measured from the channel exceeds a threshold, the LBT result is a failure. In another example, LBT may be based on signal detection. For example, when a channel reservation signal (eg, a predetermined preamble signal) is not detected in the channel, the LBT result is passed.

[0054] In some aspects, the network 100 may operate on a high frequency band (e.g., in a frequency range 1 (FR1) band or a frequency range 2 (FR2) band). FR1 may refer to frequencies in the range below 6 GHz, while FR2 may refer to frequencies in the mmWave range. To overcome the high path loss at high frequencies, the BS 105 and the UE 115 may communicate with each other using directional beams. For example, the BS 105 may transmit an SSB by scanning across a predefined set of beam directions, and may repeat the SSB transmission at a certain time interval on the set of beam directions to allow the UE 115 to perform initial network access. In some instances, each beam and its corresponding characteristics may be identified by a beam index. For example, each SSB may include an indication of a beam index corresponding to a beam used for SSB transmission. The UE 115 may determine signal measurements (such as reference signal received power (RSRP) and / or reference signal received quality (RSRQ)) for SSBs in different beam directions and select the best DL beam. UE 115 may indicate the selection by sending a PRACH signal (e.g., MSG1) using the PRACH resources associated with the selected beam direction. For example, an SSB sent in a particular beam direction may indicate a PRACH resource that UE 115 may use to communicate with BS 105 in the particular beam direction. After selecting the best DL beam, UE 115 may complete a random access procedure (e.g., a 4-step random access or a 2-step random access) and proceed with network registration and normal operational data exchange with BS 105. In some instances, the initially selected beam may not be optimal or the channel conditions may change, and therefore BS 105 and UE 115 may perform a beam refinement procedure to refine the beam selection. For example, BS 105 may send a CSI-RS by scanning a narrower beam over a narrower angular range, and UE 115 may report the best DL beam to BS 105. When BS 105 transmits using a narrower beam, BS 105 may apply a higher gain and thus may provide better performance (e.g., a higher signal-to-noise ratio (SNR)). In some instances, channel conditions may degrade and / or UE 115 may move out of the coverage of the initially selected beam, and thus UE 115 may detect a beam failure condition. Upon detecting a beam failure, UE 115 may perform BFR with BS 105 to request communication in a different beam direction.

[0055] In some aspects, the network 100 may be an IoT network, and the UE 115 may be an IoT node, such as a smart printer, monitor, gaming node, camera, audio-video (AV) production equipment, industrial IoT device, etc. The transmit payload data size of an IoT node may typically be relatively small (e.g., on the order of tens of bytes). In some aspects, the network 100 may be a large-scale IoT network serving tens of thousands of nodes (e.g., UE 115) on a high frequency band (e.g., FR1 band or FR2 band). Mechanisms for performing beamforming and beam management in a large-scale IoT network or any network with a large number of nodes (e.g., UE 115) are described in more detail herein.

[0056] Figure 1B A diagram illustrating an example disaggregated base station 102 architecture is shown. The disaggregated base station 102 architecture may include one or more central units (CUs) 150 that may communicate directly with a core network 104 via a backhaul link, or indirectly with the core network 104 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 125 via an E2 link, or a non-real-time (non-RT) RIC 145 associated with a service management and orchestration (SMO) framework 135, or both. The CU 150 may communicate with one or more distributed units (DUs) 130 via respective midhaul links, such as an F1 interface. The DU 130 may communicate with one or more radio units (RUs) 140 via respective fronthaul links. The RU 140 may communicate with respective UEs 120 via one or more radio frequency (RF) access links. In some implementations, a UE 120 may be served simultaneously by multiple RUs 140.

[0057] Each of the units (i.e., CU 150, DU 130, RU 140, and near-RT RIC 125, non-RT RIC 145, and SMO framework 135) may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive or transmit signals to one or more of the other units via a wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) configured to receive or transmit signals, or both, to one or more of the other units via a wireless transmission medium.

[0058] In some aspects, the CU 150 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by the CU 150. The CU 150 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, the CU 150 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, the CU 150 may be implemented to communicate with the DU 130 for network control and signaling.

[0059] DU 130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 140. In some aspects, DU 130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) at least in part according to a functional split such as that defined by the Third Generation Partnership Project (3GPP). In some aspects, DU 130 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 130 or with control functions hosted by CU 150.

[0060] Lower layer functionality may be implemented by one or more RUs 140. In some deployments, a RU 140 controlled by a DU 130 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, the RU 140 may be implemented to handle over-the-air (OTA) communications with one or more UEs. In some specific implementations, real-time and non-real-time aspects of control plane communications and user plane communications with the RU 140 may be controlled by the corresponding DU 130. In some scenarios, this configuration may enable the DU 130 and CU 150 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0061] The SMO framework 135 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 135 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 135 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 190) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 150, DU 130, RU 140, and near-RT RIC 125. In some specific implementations, the SMO framework 135 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 111) via the O1 interface. In addition, in some specific implementations, the SMO framework 135 may communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 135 may also include a non-RT RIC 145 that is configured to support the functionality of the SMO framework 135 .

[0062] The non-RT RIC 145 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 145 may be coupled to or in communication with the near-RT RIC 125 (such as via an A1 interface). The near-RT RIC 125 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 150, one or more DUs 130, or both, and the O-eNB with the near-RT RIC 125.

[0063] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 125, the non-RT RIC 145 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 125 and may be received from a non-network data source or from a network function at the SMO framework 135 or the non-RT RIC 145. In some examples, the non-RT RIC 145 or the near-RT RIC 125 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 145 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 135 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0064] Figure 2 2 is a timing diagram illustrating a radio frame structure 200 according to some aspects of the present disclosure. Radio frame structure 200 may be used by a BS (such as BS 105) and a UE (such as UE 115) in a network (such as network 100) to communicate. Specifically, the BS may communicate with the UE using the time-frequency resources configured as shown in radio frame structure 200. Figure 2 , the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units. Radio frame structure 200 includes radio frame 201. The duration of radio frame 201 can vary according to various aspects. In one example, radio frame 201 can have a duration of about ten milliseconds. Radio frame 201 includes M time slots 202, where M can be any suitable positive integer. In one example, M can be about 10.

[0065] Each time slot 202 includes a plurality of subcarriers 204 in frequency and a plurality of symbols 206 in time. The number of subcarriers 204 and / or the number of symbols 206 in the time slot 202 may vary according to various aspects, such as based on channel bandwidth, subcarrier spacing (SCS) and / or CP mode. One subcarrier 204 in frequency and one symbol 206 in time form one resource element (RE) 212 for transmission. A resource block (RB) 210 is formed by a plurality of consecutive subcarriers 204 in frequency and a plurality of consecutive symbols 206 in time.

[0066] In one example, a BS (e.g., Figure 1A BS 105 in the example may schedule UEs (eg, Figure 1AUE 115 in the UE 115) performs UL and / or DL ​​communication. Each time slot 202 can be time-divided into K mini-time slots 208. Each mini-time slot 208 may include one or more symbols 206. The mini-time slots 208 in the time slot 202 may have variable lengths. For example, when the time slot 202 includes N symbols 206, the mini-time slot 208 may have a length between one symbol 206 and (N-1) symbols 206. In some aspects, the mini-time slot 208 may have a length of about two symbols 206, about four symbols 206, or about seven symbols 206. In some examples, the BS may schedule the UE with a frequency granularity of a resource block (RB) 210 (e.g., which includes about 12 subcarriers 204).

[0067] FIG. 3A to FIG. 3F 300 is a signaling diagram illustrating various wireless communication methods 300 according to various aspects of the present disclosure. The method 300 may be performed by at least one UE 315, a first BS 305a, a second BS 305b, an AMF entity 301, and a UPF entity 303. One or both of the BSs 305a, 305b may be a converged BS. On the other hand, one or both of the BSs 305a, 305b may include a decomposed BS or a portion of a decomposed BS. In this regard, it should be understood that the BSs 305a, 305b may be a network entity, unit, or node configured to communicate with the UE 315, or may include a network entity, unit, or node configured to communicate with the UE. In some aspects, any one or both of the BSs 305a, 305b may be a BS 105 of the network 100 and / or the network unit 500. In this regard, any one or both of BS 305a, 305b may include a processor 502, a memory 504, an SDT module 508, a transceiver 510, and / or an antenna 516. Further, UE 315 may be one of UE 115 and / or UE 400 of network 100. In this regard, UE 315 may include a processor 402, a memory 404, an SDT module 408, a transceiver 410, and / or an antenna 416. AMF entity 301 and UPF entity 303 may be components or modules of a 5G core network and / or an LTE network. AMF entity 301 and UPF entity 303 may include hardware and / or software modules configured to perform their respective functions.

[0068] In this regard, the AMF entity 301 may include a processor, memory, instructions, modules, and transceivers configured to store, process, configure, and / or communicate flight path information to support UE handover. The AMF entity 301 may be, for example, Figure 5305a and 305b. AMF entity 301 may be responsible for functions associated with UE 315, including mode tracking, paging, radio bearer activation, authentication, handover, and flight plan communications. AMF entity 301 may communicate with BS 305a and / or 305b using NG interface, S1 interface, and / or any other suitable interface. AMF entity 301 may handle connection and handover management tasks, including communicating flight plan information to appropriate BS 305. UPF entity 303 may provide UE IP address allocation and other functions. UPF entity 303 may be connected to IP services. IP services may include the Internet, intranet, IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0069] In some aspects, the first BS 305a may be described as a receiving BS or a current serving BS. The second BS 305b may be described as a previous serving BS. In some aspects, BS 305a, 305b may communicate with each other using an Xn interface. As will become apparent in the aforementioned disclosure, method 300a may include mobility management processes and actions, such as UE context retrieval and / or relocation. For example, in some aspects, UE 315 may have performed a handover process from the second BS 305b to the first BS 305a. However, the first BS 305a currently serving UE 315 may not have the complete UE context of UE 315. In some aspects, the first BS 305a may not have any UE context in the UE context. On the contrary, the UE context may be located at the second BS 305b that previously served UE 315.

[0070] according to FIG. 3A to FIG. 3FThe method 300 shown and as will be described more fully below, the UE 315 may send a small data transmission (SDT) to at least one of the BSs 305a, 205b when in an inactive mode. For example, the UE 315 may send UL SDT data and / or UL SDT signals to the first BS 205a. The first BS 305a may send an indication of the SDT communication to the second BS 305b. The second BS 305b may be referred to as an anchor BS, a previous serving BS, or a last serving BS. The SDT transmission may be communicated using a random access communication such as an RRC recovery request. The transmission of the SDT communication may include: sending a MSG1 of a two-part or four-part RACH process. As described above, the first BS 305a may not have a complete UE context to receive the SDT communication and / or forward the SDT communication to the correct network node (e.g., AMF 301, UPF 303, etc.). Further, the second BS 305b may receive DL non-SDT data and / or DL ​​non-SDT signaling for transmission to the UE 315. For example, the second BS 305b may receive DL non-SDT data and / or DL ​​non-SDT signaling in a buffer of a radio bearer that is not enabled for SDT communication. The first BS 305a is configured as a current serving BS or receiving BS for the UE 315 and may not be aware of the arrival of DL non-SDT data and / or signaling. According to various aspects of the present disclosure, the second BS 305b may send an indication of the arrival of non-SDT data and / or signaling to the first BS 305a. In some aspects, the indication may cause the first BS 305a to complete a random access process initiated by the transmission of UL SDT data and / or signaling to move the UE 315 to a connection mode for receiving non-SDT data and / or signaling from the second BS 305b via the first BS 305a. In other aspects, the indication may cause the first BS 305a to send a random access suspend indication to keep the UE 315 in an inactive mode and prepare the UE 315 to perform additional random access procedures to receive non-SDT communications.

[0071] refer to Figure 3A In the method 300a shown, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in a connected mode.

[0072] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0073] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0074] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0075] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0076] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0077] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0078] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0079] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0080] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0081] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0082] At action 324, the second BS 305b sends a connection management or mobility message indicating the arrival of DL non-SDT communication at the second BS 305b, and the first BS 305a receives the connection management or mobility message. In some aspects, the connection management message may include a retrieval UE context response message. The message may include an indicator of the arrival of DL non-SDT data and / or signals. The message may be an Xn message. For example, in some aspects, the retrieval UE context response message may include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315. In some aspects, the retrieval UE context response includes or indicates UE context information so that the complete UE context is moved to the first BS 305a.

[0083] At action 326, the first BS 305a sends a random access message, and the UE 315 receives the random access message so that the UE 315 transitions to a connected mode or state. For example, the random access message may include a RRCResume message configured to cause the UE to move to an RRC_CONNECTED state. In some aspects, the RRCResume message may be encrypted based on a key associated with the first BS 305a. In some aspects, the first BS 305a may encrypt the RRCResume message after performing a security key refresh. For example, the first BS 305a may perform a horizontal key update to refresh its security key, and encrypt the RRCResume message based on the updated key.

[0084] At action 328, UE 315 transitions to a connected state. For example, action 328 may include UE 315 moving or transitioning to an RRC_CONNECTED state. In some aspects, UE 315 may increase monitoring, signaling, and / or other communication procedures based on moving to a connected state.

[0085] At action 330, UE 315 may send a connection completion message to the first BS 305a based on moving to the connected state, the connection completion message indicating completion of the movement to the connected mode. For example, UE 315 may send a RRCResumeComplete message to the first BS 305a.

[0086] In some aspects, the first BS 305a may indicate to the second BS 305b, AMF 301 and / or UPF 303 that the UE 315 has moved into a connected state. For example, the first BS 305a may send at least one of an Xn message or an NG message indicating that the UE 315 has moved to an RRC_CONNECTED state. On the other hand, the method 300a may also include: the second BS 305b sends DL non-SDT data and / or signaling for sending to the UE 315 to the first BS 305a. Further, the method 300a may include: when in connected mode, the first BS 305a sends DL non-SDT communications, and the UE 315 receives DL non-SDT communications. In some aspects, the method 300a may include: the first BS 305a establishes a PDCP entity and handles any further or ongoing SDT communications. In some aspects, any PDCP PDU prepared or encrypted using an old key may be resent.

[0087] refer to Figure 3BIn the method 300b of the present invention, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in the connected mode.

[0088] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0089] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0090] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0091] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0092] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0093] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0094] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0095] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0096] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0097] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0098] At action 324, the second BS 305b sends a message indicating the arrival of DL non-SDT communication at the second BS 305b, and the first BS 305a receives the message. In some aspects, the message may include an ACTIVITY NOTIFICATION message. The message may include an indicator of the arrival of DL non-SDT data and / or signals. The message may be an Xn message. For example, in some aspects, the ACTIVITY NOTIFICATION message may include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315.

[0099] In method 300b, the first BS 305a currently serving the UE 315 may be configured to or otherwise responsible for determining whether to retrieve the complete UE context from the first BS 305a and whether to move the UE 315 to the connected mode. Therefore, at action 326, the first BS 305a sends a request for a complete UE context relocation to the first BS 305a based on receiving the DL non-SDT indication. For example, the first BS 305a may send an Xn message to the second BS 305b requesting the complete UE context.

[0100] At action 328, the second BS 305b sends a complete UE context to the first BS 305a based on receiving a request for complete UE context relocation. In some aspects, action 328 includes: sending a RETRIEVE UE CONTEXT RESPONSE message including or indicating a complete UE context. In other aspects, the second BS 305b may send a different Xn message including or indicating a UE context. In some aspects, the UE context included in the message sent at action 328 may include only the portion of the UE context that has not been relocated from action 310 to the first BS 305a. In other aspects, action 328 includes: sending a complete or complete UE context. In some aspects, based on receiving the complete UE context, the first BS 305a may establish a PDCP entity and / or any other entity for handling non-SDT communications between the network and the UE 315.

[0101] At action 330, the first BS 305a sends a random access message, and the UE 315 receives the random access message to cause the UE 315 to transition to a connected mode or state. For example, the random access message may include an RRCResume message configured to cause the UE to move to an RRC_CONNECTED state. The RRCResume message may be encrypted based on a key associated with the first BS 305a.

[0102] At action 332, UE 315 transitions to a connected state. For example, action 332 may include UE 315 moving or transitioning to an RRC_CONNECTED state. In some aspects, UE 315 may increase monitoring, signaling, and / or other communication procedures based on moving to a connected state.

[0103] In some aspects, the method 300b may also include: UE 315 sends a connection completion message to the first BS 305a based on moving to a connected state, and the connection completion message indicates that the movement to the connected mode is completed. For example, UE 315 can send an RRCResumeComplete message to the first BS 305a. In some aspects, the first BS 305a may indicate to the second BS 305b, AMF301 and / or UPF 303 that UE 315 has moved to a connected state. For example, the first BS 305a may send at least one of an Xn message or an NG message indicating that UE 315 has moved to an RRC_CONNECTED state. On the other hand, the method 300b may also include: the second BS 305b sends DL non-SDT data and / or signaling for sending to UE 315 to the first BS 305a. Further, the method 300b may include: when in the connected mode, the first BS 305a sending the DL non-SDT communication, and the UE 315 receiving the DL non-SDT communication.

[0104] refer to Figure 3C In the method 300c of the present invention, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in the connected mode.

[0105] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0106] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0107] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0108] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0109] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0110] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0111] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0112] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0113] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0114] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0115] At action 324, the second BS 305b sends a message indicating the arrival of DL non-SDT communication at the second BS 305b, and the first BS 305a receives the message. In some aspects, the message may include an ACTIVITY NOTIFICATION message. The message may include an indicator of the arrival of DL non-SDT data and / or signals. The message may be an Xn message. For example, in some aspects, the ACTIVITY NOTIFICATION message may include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315.

[0116] In method 300c, the first BS 305a currently serving the UE 315 may be configured to or otherwise be responsible for determining whether to retrieve a complete UE context from the first BS 305a and whether to move the UE 315 to a connected mode. Therefore, at action 326, the first BS 305a sends a request for complete UE context relocation to the first BS 305a based on receiving a DL non-SDT indication. For example, the first BS 305a may send an Xn message to the second BS 305b requesting a complete UE context. On the other hand, the communication of action 326 also includes a pre-encrypted or unencrypted RRCResume message and a request for the second BS 305b to encrypt and return the RRCResume message.

[0117] At action 328, the second BS 305b sends a complete UE context and an encrypted RRCResume message to the first BS 305a based on receiving a request for complete UE context relocation. In some aspects, the RCResume message is encrypted based on the key of the second BS 305b. In some aspects, action 328 includes: sending a RETRIEVE UE CONTEXT RESPONSE message including or indicating a complete UE context. In other aspects, the second BS 305b may send different Xn messages including or indicating a UE context. In some aspects, the UE context included in the message sent at action 328 may only include the portion of the UE context that has not yet been relocated from action 310 to the first BS 305a. In other aspects, action 328 includes: a complete or complete UE context sent. In some aspects, based on receiving a complete UE context, the first BS 305a may establish a PDCP entity and / or any other entity for handling non-SDT communications between the network and the UE 315.

[0118] At action 330, the first BS 305a sends an encrypted RRCResume message, and the UE 315 receives the encrypted RRCResume message. The encrypted RRCResume message may cause the UE 315 to transition to a connected mode or state. For example, the encrypted RRCResume message may cause the UE to move to the RRC_CONNECTED state.

[0119] At action 332, UE 315 transitions to a connected state. For example, action 332 may include UE 315 moving or transitioning to an RRC_CONNECTED state. In some aspects, UE 315 may increase monitoring, signaling, and / or other communication procedures based on moving to a connected state.

[0120] In some aspects, the method 300c may also include: UE 315 sends a connection completion message to the first BS 305a based on moving to a connected state, and the connection completion message indicates that the movement to the connected mode is completed. For example, UE 315 can send an RRCResumeComplete message to the first BS 305a. In some aspects, the first BS 305a may indicate to the second BS 305b, AMF301 and / or UPF 303 that UE 315 has moved to a connected state. For example, the first BS 305a may send at least one of an Xn message or an NG message indicating that UE 315 has moved to an RRC_CONNECTED state. On the other hand, the method 300c may also include: the second BS 305b sends DL non-SDT data and / or signaling for sending to UE 315 to the first BS 305a. Further, the method 300c may include: when in the connected mode, the first BS 305a sending the DL non-SDT communication, and the UE 315 receiving the DL non-SDT communication.

[0121] refer to Figure 3D In the method 300d shown, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in a connected mode.

[0122] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0123] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0124] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0125] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0126] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0127] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0128] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0129] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0130] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0131] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0132] At action 324, the second BS 305b sends a release message for the UE 315, and the first BS 305a receives the release message so that the UE 315 suspends the RRC recovery process. In some aspects, action 324 includes: sending a RETRIEVE UE CONTEXT FAILURE message indicating that the complete UE context will not be transferred to the first BS 305a. In some aspects, action 324 also includes: an RRCRelease message sent to the first BS 305a. The RRCRelease message can be encrypted based on a key associated with the second BS 305b. The message and / or message sent at action 324 can also indicate the arrival of DL non-SDT communication at the second BS 305b. The message or message can be an Xn message. For example, in some aspects, the RETRIEVE UECONTEXT FAILURE message can include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315.

[0133] At action 326, the first BS 305a sends a random access message, and the UE 315 receives the random access message so that the UE 315 remains in an inactive mode or state, so that the RRCResume process is suspended. For example, the random access message may include an RRCRelease message, which includes a suspension configuration indication so that the UE remains in the RRC_INACTIVE state or returns to the RRC_INACTIVE state. In some aspects, the RRCRelease message may be encrypted based on a key associated with the second BS 305b. In other aspects, the RRCRelease message may be encrypted based on a key associated with the first BS 305a. Further, the RRCRelease message may include an indication of the arrival of a DL non-SDT communication.

[0134] At action 328, the UE 315 remains in the inactive mode or returns to the inactive mode. For example, action 328 may include: the UE 315 remains in the RRC_INACTIVE state.

[0135] At action 330, UE 315 may initiate a random access procedure based on receiving the RRCRelease message and returning to inactive mode. For example, UE 315 may send a RACH preamble to the first BS 305a. In some aspects, UE 315 may initiate a two-step RACH procedure. In other aspects, UE 315 may initiate a four-step RACH procedure.

[0136] In some aspects, the method 300d can provide for accelerated re-initiation of the RACH process so that the UE 315 can transition to the connected mode in an accelerated manner for faster reception of the DL non-SDT data and / or signaling indicated to the UE 315 at action 326. In other words, the UE 315 can be made aware that the reason for the SDT termination is due to the arrival of DL non-SDT communications. In some aspects, the UE 315 can adjust or modify its SDT process based on the indication of the arrival of non-SDT data and / or signaling. For example, the UE 315 can disable the SDT protocol in the future to facilitate returning to the connected mode for SDT and / or non-SDT communications.

[0137] refer to Figure 3EIn the method 300e shown, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in the connected mode.

[0138] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0139] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0140] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0141] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0142] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0143] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0144] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0145] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0146] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0147] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0148] At action 324, the second BS 305b sends a release message for the UE 315, and the first BS 305a receives the release message so that the UE 315 suspends the RRC recovery process. In some aspects, action 324 includes: sending a RETRIEVE UE CONTEXT FAILURE message indicating that the complete UE context will not be transferred to the first BS 305a. In some aspects, action 324 also includes: an RRCRelease message sent to the first BS 305a. The RRCRelease message can be encrypted based on a key associated with the second BS 305b. The message and / or message sent at action 324 can also indicate the arrival of DL non-SDT communication at the second BS 305b. The message or message can be an Xn message. For example, in some aspects, the RETRIEVE UECONTEXT FAILURE message can include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315.

[0149] In another aspect, the release message may include or indicate a contention-free RACH (CFRA) resource that is used by the UE 315 to accelerate a new RRC Resume process to move to connected mode. The CFRA resource may include time and / or frequency resources that are used by the UE to send one or more random access communications, such as a RACH preamble.

[0150] At action 326, the first BS 305a sends a random access message, and the UE 315 receives the random access message so that the UE 315 remains in an inactive mode or state, so that the RRCResume process is suspended. For example, the random access message may include an RRCRelease message, which includes a suspension configuration indication so that the UE remains in the RRC_INACTIVE state or returns to the RRC_INACTIVE state. In some aspects, the RRCRelease message may be encrypted based on a key associated with the second BS 305b. In other aspects, the RRCRelease message may be encrypted based on a key associated with the first BS 305a. Further, the RRCRelease message may include an indication of the arrival of a DL non-SDT communication. On the other hand, the random access message sent at action 326 may include or indicate the CFRA resource indicated at action 324.

[0151] At action 328, the UE 315 remains in the inactive mode or returns to the inactive mode. For example, action 328 may include: the UE 315 remains in the RRC_INACTIVE state.

[0152] At action 330, UE 315 may initiate a random access procedure using the indicated CFRA resources based on receiving the RRCRelease message and returning to inactive mode. For example, UE 315 may use the CFRA resources to send a RACH preamble to the first BS 305a. In some aspects, UE 315 may initiate a two-step RACH procedure. In other aspects, UE 315 may initiate a four-step RACH procedure.

[0153] In some aspects, the method 300e can provide for accelerated re-initiation of the RACH process so that the UE 315 can transition to the connected mode in an accelerated manner for faster reception of the DL non-SDT data and / or signaling indicated to the UE 315 at action 326. In other words, the UE 315 can be made aware that the reason for the SDT termination is due to the arrival of DL non-SDT communications. In some aspects, the UE 315 can adjust or modify its SDT process based on the indication of the arrival of non-SDT data and / or signaling. For example, the UE 315 can disable the SDT protocol in the future to facilitate returning to the connected mode for SDT and / or non-SDT communications.

[0154] refer to Figure 3F In the method 300f shown, at action 302, UE 315 is in an inactive mode or state. For example, UE 315 may be in a radio resource control (RRC) inactive state (RRC_INACTIVE) and a connection management connection state (CM-CONNECTED). In other aspects, at action 302, UE 315 may be in an idle mode, such as RRC_IDLE. In the inactive mode, UE 315 may perform limited or reduced signaling and / or monitoring to reduce power consumption. In some aspects, UE 315 may transition to the inactive mode in response to receiving a release and / or pause message when in the connected mode.

[0155] At action 304, UE 315 sends a random access communication including uplink (UL) SDT data and / or signaling, and the first BS 305a receives the random access communication including uplink (UL) SDT data and / or signaling. In some aspects, the random access communication includes a connection request or a recovery connection request. In some aspects, the message includes an RRCResumeRequest message. In some aspects, the random access communication includes a RACH preamble. In other aspects, the random access communication includes a combination of an RRCResumeRequest message and a RACH preamble. UL SDT data and / or signaling can be included in a single message or transmission together with the random access communication. For example, UE 315 can send an RRCResumeRequest message and UL SDT data and / or signaling in the same physical uplink shared channel (PUSCH) transmission. In other aspects, random access communications and UL SDT data and / or signaling can be carried in separate messages or communications.

[0156] At action 306, the first BS 305a sends a request to retrieve the UE context to the second BS 305b in response to receiving the random access communication and the UL SDT data and / or signaling at action 304. In some aspects, sending the request may include sending a RETREIVE UE CONTEXT REQUEST message. In some aspects, the message may include an SDT indicator indicating the arrival of the UL SDT data and / or signaling. The message may also include UE assistance information. The UE assistance information may be based on the communication received by the first BS 305a at action 304. In some aspects, the request to retrieve the UE context may include an Xn message.

[0157] At action 308, the second BS 305b determines or decides to keep at least a portion of the UE context. In this regard, the second BS 305b may determine not to transfer the complete UE context to the first BS 305a. For example, the second BS 305b may determine to send a portion of the UE context. For example, the second BS 305b may determine to transfer a first portion of the UE context so that the first BS 305a can establish an SDT radio bearer, such as a data radio bearer (DRB) or a signaling radio bearer (SRB). The second BS 305b may keep a portion of the UE context to establish a packet data convergence protocol (PDCP) entity.

[0158] At action 310, the second BS 305b sends a partial UE context transfer, and the first BS 305a receives the partial UE context transfer. The partial UE context transfer may include a UE identifier, UE capability information, configuration parameters, subscription information, security information, and / or other information associated with the UE to enable the first BS 305a to receive, decode, and / or transfer SDT data and / or signaling. In some aspects, the partial UE context transfer may be sent using an Xn message.

[0159] At action 312, the first BS 305a sends a partial UE context transfer confirmation message to the second BS 305b. In some aspects, the partial UE context transfer confirmation message may include an Xn message. In some aspects, the partial UE context transfer confirmation message may indicate that the partial UE context is received by the first BS 305a.

[0160] At action 314, the first BS 305a establishes an SDT RLC entity based on the partial UE context transfer. In some aspects, the SDT RLC entity is based on the partial UE context received from the second BS 305b. In some aspects, the SDT RLC entity can enable the first BS 305a to receive, forward, decode and / or otherwise handle SDT data and / or signaling to and from the UE 315.

[0161] At action 316, the second BS 305b establishes or maintains a PDCP entity based on the portion of the UE context maintained by the second BS 305b. In some aspects, the PDCP entity may enable the second BS 305b to receive, decode, forward and / or otherwise handle non-SDT communications to and from the UE 315.

[0162] At action 318, the first BS 305a sends the UL SDT data and / or signaling received at action 304 to the second BS 305b. In some aspects, sending the UL SDT communication may include: the first BS 305a sends the UL SDT communication to the second BS 305b in an Xn message. The second BS 305b forwards or transfers the UL SDT communication to the UPF 303. In some aspects, the transfer of the SDT communication to the UPF 303 can be based on the NG interface. For example, the second BS 305b can forward the UL SDT communication to the UPF 303 in an NG-U message. On the other hand, the second BS 305b can forward the UL SDT communication to the AMF 301 in an NG-C message.

[0163] At action 320, when UE 315 is in inactive mode, UE 315, first BS 305a, second BS 305b, AMF 301 and / or UPF 303 perform additional UL and / or DL ​​SDT transmissions. In some aspects, one or more of the SDT communications communicated at action 320 may include SDT data. On the other hand, one or more of the SDT communications communicated at action 320 include SDT signals. In some aspects, action 320 may include: first BS 305a sends one or more UL SDT signals to second BS 305b via RRC transfer message. Then, second BS 305b may send UL NAS PDU including UL SDT signal to AFM 301 via UL NAS transmission message. On the other hand, action 320 may include: the first BS 305a sends UL SDT data to the first BS 305a via PUSCH communication, the first BS 305a forwards the UL SDT data to the second BS 305b via Xn communication, and the second BS 305b forwards the UL SDT data to the UPF 303 via NG-U communication.

[0164] At act 322, the second BS 305b receives DL non-SDT data and / or DL ​​non-SDT signals while the UE 315 remains in the inactive mode. In some aspects, the second BS 305b receives the DL non-SDT data and / or signals in a buffer of a radio bearer that is not enabled for SDT communications.

[0165] At action 324, the second BS 305b sends a release message for the UE 315, and the first BS 305a receives the release message so that the UE 315 suspends the RRC recovery process. In some aspects, action 324 includes: sending a RETRIEVE UE CONTEXT FAILURE message indicating that the complete UE context will not be transferred to the first BS 305a. In some aspects, action 324 also includes: an RRCRelease message sent to the first BS 305a. The RRCRelease message can be encrypted based on a key associated with the second BS 305b. The message and / or message sent at action 324 can also indicate the arrival of DL non-SDT communication at the second BS 305b. The message or message can be an Xn message. For example, in some aspects, the RETRIEVE UECONTEXT FAILURE message can include at least one field for indicating whether non-SDT data is scheduled for transmission to the UE 315.

[0166] At action 326, the first BS 305a sends a random access message, and the UE 315 receives the random access message so that the UE 315 remains in an inactive mode or state, so that the RRCResume process is suspended. For example, the random access message may include an RRCRelease message, which includes a suspension configuration indication so that the UE remains in the RRC_INACTIVE state or returns to the RRC_INACTIVE state. In some aspects, the RRCRelease message can be encrypted based on a key associated with the second BS 305b. In other aspects, the RRCRelease message can be encrypted based on a key associated with the first BS 305a.

[0167] At action 328, the UE 315 remains in the inactive mode or returns to the inactive mode. For example, action 328 may include: the UE 315 remains in the RRC_INACTIVE state.

[0168] At action 330, the first BS 305a sends a radio access network (RAN) paging message indicating the arrival of DL non-SDT data and / or signaling, and the UE 315 receives the radio access network (RAN) paging message. In some aspects, the paging message may cause the UE 315 to initiate another random access process. For example, receiving the paging message may cause the UE 315 to send a new RRCResume message to the first BS 305a. In some aspects, the method 300f may provide an accelerated re-initiation of the RACH process so that the UE 315 may transition to a connected mode in an accelerated manner for faster reception of the DL non-SDT data and / or signaling indicated to the UE 315 at action 326. In other words, due to the non-SDT indication in the paging message, the UE 315 may be made aware that the reason for the SDT termination is due to the arrival of DL non-SDT communications. In some aspects, the UE 315 may adjust or modify its SDT process based on the indication of the arrival of non-SDT data and / or signaling. For example, the UE 315 may disable the SDT protocol in the future in favor of returning to a connected mode for SDT and / or non-SDT communications.

[0169] Figure 4 4 is a block diagram of an exemplary UE 400 according to some aspects of the present disclosure. UE 400 may be the Figure 1A UE 115 discussed in or above in FIG. 3A to FIG. 3F315 discussed in . As shown, UE 400 may include a processor 402, a memory 404, an SDT module 408, a transceiver 410 including a modem subsystem 412 and a radio frequency (RF) unit 414, and one or more antennas 416. These elements may communicate with each other directly or indirectly, for example, via one or more buses.

[0170] The processor 402 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 402 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0171] The memory 404 may include cache memory (e.g., cache memory of the processor 402), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory devices, hard drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In one aspect, the memory 404 includes a non-transitory computer-readable medium. The memory 404 may store or have recorded thereon instructions 406. The instructions 406 may include instructions that, when executed by the processor 402, cause the processor 402 to perform various aspects of the present disclosure (e.g., FIG. 3A to FIG. 3F , Figure 6 , Figure 7 and / or Figure 8 Instructions 406 may also be referred to as program code. Program code may be used to cause the wireless communication device to perform these operations, for example, by causing one or more processors (such as processor 402) to control or command the wireless communication device to do so. The terms "instructions" and "code" should be broadly interpreted to include any type of computer-readable statements. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or multiple computer-readable statements.

[0172] The SDT module 408 may be implemented by hardware, software, or a combination thereof. For example, the SDT module 408 may be implemented as a processor, circuit, and / or instructions 406 stored in the memory 404 and executed by the processor 402. In some examples, the SDT module 408 may be integrated within the modem subsystem 412. For example, the SDT module 408 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 412.

[0173] The SDT module 408 can be used in various aspects of the present disclosure, such as FIG. 3A to FIG. 3F , Figure 6 , Figure 7 and / or Figure 8 Aspects of various aspects of the present invention. The SDT module 408 is configured to communicate SDT data and / or signaling with the network, or to cause the transceiver 410 to communicate SDT data and / or signaling with the network. In some aspects, the SDT module 408 may be configured to cause the transceiver 410 to send and / or receive random access messages for communicating SDT communications and / or non-SDT communications. For example, the SDT module 408 may be configured to cause the transceiver 410 to send RRCResumeRequest messages, UL SDT data, UL SDT signals, RRCResumeComplete messages, and / or any other suitable type of communication. On the other hand, the SDT module 408 may be configured to cause the transceiver 410 to receive random access communications, SDT communications, and / or non-SDT communications from one or more network nodes. For example, the SDT module 408 may be configured to cause the transceiver 410 to receive RRCResume messages, DL SDT data, DL SDT signals, DL non-SDT data, DL non-SDT signals, RRCRelease messages, and / or any other suitable type of communication. In some aspects, the SDT module 408 is configured to determine whether to communicate SDT data and / or signaling based on an indication of the arrival of non-SDT data or signaling at the network. For example, the SDT module 408 can update or modify the SDT protocol or configuration based on an indication of a failed SDT session based on the arrival of DL non-SDT data and / or signaling.

[0174] As shown, the transceiver 410 may include a modem subsystem 412 and an RF unit 414. The transceiver 410 may be configured to communicate bidirectionally with other devices, such as the BS 105. The modem subsystem 412 may be configured to modulate and / or encode data from the memory 404 and / or the SDT component 408 according to a modulation and coding scheme (MCS) (e.g., a low-density parity check (LDPC) decoding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 414 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data (e.g., PUCCH control information, PRACH signals, PUSCH data, SDT data, non-SDT data, reference signals, RRC messages, etc.) from the modem subsystem 412 (for outbound transmissions) or from another source, such as the UE 115 or the BS 105. The RF unit 414 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in the transceiver 410, the modem subsystem 412 and the RF unit 414 may be separate devices that are coupled together at the UE 115 to enable the UE 115 to communicate with other devices.

[0175] The RF unit 414 may provide modulated and / or processed data, such as data packets (or more generally, data messages that may include one or more data packets and other information), to the antenna 416 for transmission to one or more other devices. The antenna 416 may also receive data messages sent from other devices. The antenna 416 may provide the received data messages for processing and / or demodulation at the transceiver 410. The transceiver 410 may provide the demodulated and decoded data (e.g., SSB, PDCCH, PDSCH, RRC message, SDT data, SDT signal, etc.) to the SDT module 408 for processing. The antenna 416 may include multiple antennas of similar design or different design in order to maintain multiple transmission links. The RF unit 414 may configure the antenna 416.

[0176] In one aspect, the UE 400 may include multiple transceivers 410 that implement different RATs (e.g., NR and LTE). In one aspect, the UE 400 may include a single transceiver 410 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 410 may include various components, where different combinations of components may implement different RATs.

[0177] Figure 5 is a block diagram of an exemplary network node 500 according to some aspects of the present disclosure. The network node 500 may be as described above in Figure 1A BS 105 in network 100 discussed in or above in FIG. 3A to FIG. 3F As shown, the network node 500 may include a processor 502, a memory 504, an SDT module 508, a transceiver 510 including a modem subsystem 512 and an RF unit 514, and one or more antennas 516. These elements may communicate with each other directly or indirectly, for example, via one or more buses. It should be understood that Figure 5 The network node 500 shown may be a BS and / or any other suitable type of network node or network element. For example, the network node 500 may include a converged BS or a decomposed BS, as described above for Figure 1A Described by B.

[0178] The processor 502 may have various features that are specific types of processors. For example, these features may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 502 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0179] The memory 504 may include cache memory (e.g., cache memory of the processor 502), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory 504 may include a non-transitory computer-readable medium. The memory 504 may store instructions 506. The instructions 506 may include instructions that, when executed by the processor 502, cause the processor 502 to perform the operations described herein (e.g., FIG. 3A to FIG. 3F , Figure 6 , Figure 7 and / or Figure 8 Instructions 506 may also be referred to as code, which may be broadly interpreted as including any type of computer-readable statements, such as those described above. Figure 4 discussed.

[0180] The SDT module 508 may be implemented by hardware, software, or a combination thereof. For example, the SDT module 508 may be implemented as a processor, circuit, and / or instructions 506 stored in the memory 504 and executed by the processor 502. In some examples, the SDT module 508 may be integrated within the modem subsystem 512. For example, the SDT module 508 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 512.

[0181] The SDT module 508 can be used in various aspects of the present disclosure, such as FIG. 3A to FIG. 3F , Figure 6 , Figure 7 and / or Figure 8 Aspects of various aspects. The SDT module 508 is configured to receive and / or send SDT communications, including SDT data and / or SDT signaling. The SDT module 508 may be configured to: communicate random access and / or connection management communications with the UE, or cause the transceiver 510 to communicate random access and / or connection management communications with the UE. For example, the SDT module 508 may be configured to receive a RRCResumeRequest message, UL SDT data, UL SDT signal, RRCResumeComplete message, retrieve UE context message, UE context message, retrieve UE context failure message, RRCRelease message and / or any other suitable type of message. The SDT module 508 may be configured to send a RRCResume message, retrieve a UE context message, retrieve a UE context failure message, a RRCRelease message, a UE context message, DL SDT data, a DL SDT signal, a RAN paging message, and / or any other suitable type of message, or cause the transceiver 510 to send a RRCResume message, retrieve a UE context message, retrieve a UE context failure message, a RRCRelease message, a UE context message, DL SDT data, a DL SDT signal, a RAN paging message, and / or any other suitable type of message. In some aspects, the SDT module 508 is configured to receive and / or provide an indication of the arrival of non-SDT data and / or signals for transmission, for transmission to the UE. In some aspects, the SDT module 508 is configured to request and / or provide a UE context based on the indication. In some aspects, the SDT module 508 is configured to communicate an unencrypted RRC message together with a request for encryption by a different network node.

[0182] As shown, the transceiver 510 may include a modem subsystem 512 and an RF unit 514. The transceiver 510 may be configured to communicate bidirectionally with other devices (such as UE 115 and / or 300 and / or another core network element). The modem subsystem 512 may be configured to modulate and / or encode data according to an MCS (e.g., an LDPC decoding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 514 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data (e.g., SSB, RMSI, MIB, SIB, FBE configuration, PRACH configuration PDCCH, PDSCH) from the modem subsystem 512 (for outbound transmission) or from another source (such as UE 115, UE 315 and / or UE 400). The RF unit 514 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in transceiver 510, modem subsystem 512 and / or RF unit 514 may be separate devices that are coupled together at BS 105 to enable BS 105 to communicate with other devices.

[0183] The RF unit 514 may provide modulated and / or processed data, such as data packets (or more generally, data messages that may include one or more data packets and other information), to the antenna 516 for transmission to one or more other devices. For example, according to some aspects of the present disclosure, this may include the transmission of information to complete the attachment to the network and the communication with the pre-occupied UE 115 or 215. The antenna 516 may also receive data messages sent from other devices and provide the received data messages for processing and / or demodulation at the transceiver 510. The transceiver 510 may provide the demodulated and decoded data (e.g., PUCCH control information, PRACH signals, PUSCH data) to the SDT module 508 for processing. The antenna 516 may include multiple antennas of similar design or different design in order to maintain multiple transmission links.

[0184] In one example, the transceiver 510 is configured to: send system information including an FBE configuration indicating multiple frame periods to the UE, each frame period including a gap period for contention at the beginning of the frame period; and communicate with the UE based on the FBE configuration, for example, by coordinating with the SDT module 508.

[0185] In one aspect, the network node 500 may include multiple transceivers 510 that implement different RATs (e.g., NR and LTE). In one aspect, the network node 500 may include a single transceiver 510 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 510 may include various components, where different combinations of components may implement different RATs.

[0186] Figure 6 6 is a flow chart of a communication method 600 according to some aspects of the present disclosure. The steps of the method 600 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of an apparatus or other suitable means for performing the steps. For example, a network node (such as BS 105, network node 305, and / or one of network nodes 500) may utilize one or more components (such as processor 502, memory 504, SDT module 508, transceiver 510, and one or more antennas 516) to perform the steps of the method 600. The method 600 may be implemented in the same manner as described above for FIG. 3A to FIG. 3F Similar mechanisms are described in methods 300a to 300f. As illustrated, method 600 includes a plurality of the enumerated steps, but aspects of method 600 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0187] In block 610, the first network element receives a UL SDT from a UE in an inactive mode. In some aspects, the UL SDT includes UL SDT data. In other aspects, the UL SDT includes a UL SDT signal. In some aspects, receiving the UL SDT may include receiving the UL SDT in a PUCCH, a PUSCH, and / or any other suitable UL physical channel. In some aspects, the first network element may receive the UL SDT when the UE is in an RRC_INACTIVE mode or state. In some aspects, block 610 may include receiving an RRC recovery request message from the UE along with the UL SDT.

[0188] In block 620, the first network element receives from the second network element an indication of the arrival of non-SDT communications scheduled for transmission to the UE at the second network element. The non-SDT communications may include DL data and / or DL ​​signals. For example, the second network element may receive DL data and / or signaling in a buffer of a radio bearer that is not enabled for SDT communications. In some aspects, the first network element may currently serve the UE and be configured to communicate with the UE. The second network element may be a last serving network element and / or an anchor network element. The second network element may maintain a UE context. For example, the network may have performed a handover procedure to transfer the UE from a cell associated with the second network element to a cell associated with the first network element. However, the first network element may not have a complete UE context for handling SDT and / or non-SDT communications.

[0189] In box 630, the first network unit sends a random access communication to the UE based on the indication to: move the UE into a connected mode; or keep the UE in an inactive mode. For example, in one aspect, box 630 includes: sending a RRCResume message to move the UE to RRC_CONNECTED mode. On the other hand, box 630 includes: sending a RRCRelease message with a pause configuration indication to keep the UE in an inactive mode. In some aspects, the random access communication may indicate the arrival of a non-SDT communication at the second network unit. In some aspects, the random access communication may indicate resources for the UE to perform additional random access or mobility procedures to move to a connected mode. For example, box 630 may include: the second network unit sends an indication to the UE of one or more contention-free RACH (CFRA) resources for the UE to send at least one of a RRCResumeRequest message or a RACH preamble.

[0190] In some aspects, the method 600 also includes: sending a request for UE context relocation to the second network element. For example, the first network element may send an Xn message including a request for a complete UE context transfer. On the other hand, the method 600 may include: receiving a UE context from the second network element. In some aspects, the second network element may send the UE context based on a request from the first network element. On the other hand, the second network element may send the UE context without a request and in response to the arrival of a non-SDT communication. In some aspects, the method 600 includes: determining by the first network element whether to request a complete UE context relocation and whether to move the UE to a connected mode based on receiving an indication of the arrival of a non-SDT communication at the second network element. In some aspects, the first network element may request UE context relocation and may send an RRC recovery message to the UE based on the determination.

[0191] In some aspects, method 600 includes: sending a RRCResume message and a request to encrypt the RRCResume message with a key of the second network unit to the second network unit. In this regard, the first network unit can send an unencrypted or pre-encrypted RRCResume message to the second network unit. Then, the first network unit can receive the RRCResume message encrypted with the key of the second network unit from the second network unit. Then, the first network unit can send the encrypted RRCResume message to the UE via the Uu link. For example, the first network unit can send the encrypted RRCResume message in the PDSCH.

[0192] In some aspects, box 630 includes: sending a RRCRelease message so that the UE suspends the RRCResume process and remains in an inactive mode. In some aspects, method 600 includes: receiving a RRCRelease message encrypted with a key of the second network unit from a second network unit via an Xn interface, and forwarding the RRCRelease message to the UE via a Uu interface. In some aspects, the RRCRelease message may include or be associated with a retrieval UE context failure message. In some aspects, the first network unit may send an indication of the arrival of non-SDT communication together with the RRCRelease message. In some aspects, the first network unit may also indicate CFRA resources for the UE to initiate further random access or mobility procedures to move to a connected mode. In some aspects, method 600 also includes: when the UE is in an inactive mode, sending a RAN paging message to the UE, wherein the RAN paging message indicates the arrival of non-SDT communication.

[0193] Figure 7 700 is a flow chart of a communication method 700 according to some aspects of the present disclosure. The steps of the method 700 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of an apparatus or other suitable means for performing the steps. For example, a network node (such as BS 105, network node 305, and / or one of network nodes 500) may utilize one or more components (such as processor 502, memory 504, SDT module 508, transceiver 510, and one or more antennas 516) to perform the steps of the method 700. The method 700 may be implemented in the same manner as described above for FIG. 3A to FIG. 3F Similar mechanisms are described in methods 300a to 300f. As illustrated, method 700 includes a plurality of the enumerated steps, but aspects of method 1000 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0194] In block 710, a first network element receives a UL SDT from a UE in an inactive mode. In some aspects, the UL SDT includes UL SDT data. In other aspects, the UL SDT includes a UL SDT signal. In some aspects, receiving the UL SDT may include: receiving the UL SDT via a second network element in communication with the UE. In some aspects, when the UE is in an RRC_INACTIVE mode or state, the first network element may receive the UL SDT from a second network element currently serving the UE. In some aspects, block 710 may include: receiving an RRC recovery request message together with the UL SDT. In some aspects, the method 700 includes: the first network element receives a request to retrieve a UE context including an indication of the UL SDT from the second network element. In some aspects, the first network element may determine to relocate only a portion of the UE context to the second network element and determine to maintain at least a portion of the UE context. In some aspects, the first network element may receive the UL SDT from the second network element based on sending a portion of the UE context to the second network element.

[0195] At block 720, the first network element receives at least one of non-SDT DL data or non-SDT DL signals scheduled for transmission to the UE. For example, the first network element may receive DL data and / or signaling in a buffer of a radio bearer that is not enabled for SDT communication. In some aspects, the second network element may currently serve the UE and be configured to communicate with the UE. The first network element may be a last serving network element and / or an anchor network element. The first network element may maintain a complete UE context. For example, the network may have performed a handover procedure to transfer the UE from a cell associated with the first network element to a cell associated with the second network element.

[0196] At block 730, the first network element sends an indication of arrival of the non-SDT DL data or non-SDT DL signal to the second network element in response to receiving the non-SDT DL data or non-SDT DL signal. In some aspects, block 730 also includes the first network element sending UE context information associated with the UE to the second network element.

[0197] In some aspects, the method 700 also includes: receiving a request for UE context relocation from the second network element. For example, the first network element may receive an Xn message including a request for a complete UE context transfer. On the other hand, the method 700 may include: sending the UE context to the second network element. In some aspects, the first network element may send the UE context based on a request from the second network element. On the other hand, the first network element may send the UE context without a request and in response to the arrival of a non-SDT communication. In some aspects, the method 700 includes: determining, by the first network element, whether to move the UE to a connected mode. In some aspects, the first network element may send an RRC recovery message to the second network element based on the determination for sending to the UE.

[0198] In some aspects, method 700 includes: receiving a RRCResume message from a second network element and a request to encrypt the RRCResume message with a key of the first network element. In this regard, the second network element may send an unencrypted or pre-encrypted RRCResume message to the first network element. The first network element may then send the RRCResume message encrypted with the key of the second network element to the second network element. The second network element may then send the encrypted RRCResume message to the UE via a Uu link.

[0199] In some aspects, method 700 includes: sending a RRCRelease message so that the UE suspends the RRCResume process and remains in an inactive mode. In some aspects, method 700 includes: sending a RRCRelease message encrypted with a key of the first network unit to the second network unit via an Xn interface. In some aspects, the RRCRelease message may include or be associated with a retrieval UE context failure message. In some aspects, the first network unit may send an indication of the arrival of non-SDT communication together with the RRCRelease message. In some aspects, the first network unit may also indicate CFRA resources for the UE to initiate further random access or mobility procedures to move to connected mode.

[0200] Figure 8800 is a flow chart of a communication method 800 according to some aspects of the present disclosure. The steps of method 800 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of an apparatus or other suitable means for performing the steps. For example, a UE (such as one of UE 115, UE 315, and / or UE 400) may utilize one or more components (such as processor 402, memory 404, SDT module 408, transceiver 410, and one or more antennas 416) to perform the steps of method 800. Method 800 may be implemented in the same manner as described above for FIG. 3A to FIG. 3F Similar mechanisms are described in methods 300a to 300f. As illustrated, method 800 includes a plurality of the steps listed, but aspects of method 800 may include additional steps before, after, and between the steps listed. In some aspects, one or more of the steps listed may be omitted or performed in a different order.

[0201] In block 810, the UE sends a first random access communication while in an inactive mode to move the UE into a connected mode. The random access communication may also include a UL SDT. In some aspects, the UL SDT includes UL SDT data. In other aspects, the UL SDT includes a UL SDT signal. In some aspects, receiving the UL SDT may include receiving the UL SDT in a PUCCH, a PUSCH, and / or any other suitable UL physical channel. In some aspects, the UE may send a random access communication and a UL SDT while the UE is in an RRC_INACTIVE mode or state. In some aspects, block 810 may include sending an RRC recovery request message to a network element along with the UL SDT.

[0202] In block 820, the UE receives a second random access communication from the first network element to keep the UE in the inactive mode when the UE is in the inactive mode. In some aspects, the second random access communication may include an RRC release message. The RRC release message may include a suspension configuration indication. In some aspects, the second random access communication also includes an indication of the arrival of a non-SDT communication scheduled for transmission to the UE at the second network element. The non-SDT communication may include DL data and / or DL ​​signals. For example, the second network element may receive DL data and / or signaling in a buffer of a radio bearer that is not enabled for SDT communication. In some aspects, the first network element may currently serve the UE and be configured to communicate with the UE. The second network element may be the last serving network element and / or the anchor network element. The second network element may maintain the UE context. For example, the network may have performed a handover process to transfer the UE from a cell associated with the second network element to a cell associated with the first network element. However, the first network element may not have a complete UE context for handling SDT and / or non-SDT communications.

[0203] In box 830, the UE sends a third random access communication based on the indication to move the UE into connected mode. For example, the third random access communication may include a second RRC recovery request message to move to connected mode. In some aspects, sending the RRC recovery request message may be performed based on the CFRA resources indicated in the second random access message. On the other hand, box 830 includes: sending an RRCRelease message with a pause configuration indication to keep the UE in an inactive mode. In some aspects, the random access communication may indicate the arrival of a non-SDT communication at a second network element. In some aspects, the random access communication may indicate resources for the UE to perform additional random access or mobility procedures to move to connected mode. For example, box 830 may include: the second network element sends an indication to the UE of one or more contention-free RACH (CFRA) resources for the UE to send at least one of an RRCResumeRequest message or a RACH preamble.

[0204] Exemplary Aspects of the Disclosure

[0205] Aspect 1. A method of wireless communication performed by a first network unit, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving an indication of the arrival of at least one of non-SDT downlink (DL) data or non-SDT DL signals scheduled for the UE at the second network unit from a second network unit; and sending a random access communication to the UE based on the indication to: move the UE into a connected mode; or keep the UE in the inactive mode.

[0206] Aspect 2. The method according to aspect 1, wherein the sending the random access communication includes sending a radio resource control (RRC) resume message to move the UE into the connected mode.

[0207] Aspect 3. The method according to aspect 2 further comprises: receiving UE context information associated with the UE from the second network element.

[0208] Aspect 4. A method according to aspect 3, wherein: the receiving the UE context information includes receiving a UE context request response; and the UE context request response includes the indication of the at least one of the non-SDT DL data or the non-SDT DL signal.

[0209] Aspect 5. According to the method according to any one of aspects 3 to 4, the method further includes: sending a request for the UE context information to the second network element in response to receiving the indication.

[0210] Aspect 6. A method according to Aspect 5, wherein: the sending of the request for the UE context information includes sending a pre-encrypted RRC recovery message to the second network element; and the method further includes: receiving the RRC recovery message from the second network element, wherein the RRC recovery message is encrypted based on a key associated with the second network element; and the sending of the RRC recovery message includes sending the RRC recovery message encrypted based on the key associated with the second network element.

[0211] Aspect 7. The method according to any one of aspects 1 to 6, wherein the sending the random access communication comprises sending a radio resource control (RRC) release message to keep the UE in the inactive mode.

[0212] Aspect 8. The method according to aspect 7, wherein the RRC release message indicates the arrival of the non-SDT DL data or the non-SDT DL signal.

[0213] Aspect 9. A method according to any one of Aspects 7 to 8, wherein the receiving the indication comprises: receiving the RRC release message from the second network element, wherein the RRC release message indicates: UE context relocation failure; and the arrival of the non-SDT DL data or the non-SDT DL signal.

[0214] Aspect 10. The method according to aspect 9, wherein: the RRC release message indicates a random access resource, and the method further comprises: receiving a random access preamble from the UE based on the random access resource.

[0215] Aspect 11. According to any one of aspects 7 to 10, the method further includes: sending a paging message to the UE after sending the RRC release message, the paging message indicating the arrival of the non-SDT DL data or the non-SDT DL signal.

[0216] Aspect 12. A method of wireless communication performed by a first network unit, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving at least one of non-SDT downlink (DL) data or non-SDT DL signals scheduled for the UE; and in response to receiving the at least one of the non-SDT DL data or the non-SDT DL signal, sending to a second network unit: an indication of the non-SDT DL data or the non-SDT DL signal received at the first network unit; and UE context information associated with the UE.

[0217] Aspect 13. A method according to aspect 12, wherein: the sending of the UE context information includes sending a UE context request response; and the UE context request response includes the indication of the at least one of the non-SDT DL data or the non-SDT DL signal.

[0218] Aspect 14. The method according to any one of aspects 12 to 13, the method further comprising: receiving a request for the UE context information from the second network element, wherein the sending of the UE context information is based on the request for the UE context information.

[0219] Aspect 15. A method according to Aspect 14, wherein: the receiving of the request for the UE context information includes receiving a pre-encrypted radio resource control (RRC) recovery message from the second network element, the pre-encrypted RRC recovery message indicating the request for the UE context information; and the method further includes: sending the RRC recovery message encrypted with a key associated with the first network element to the second network element.

[0220] Aspect 16. A method according to any one of Aspects 12 to 16, wherein the sending the indication comprises sending a radio resource control (RRC) release message to move the UE into the inactive mode, wherein the RRC release message comprises the indication.

[0221] Aspect 17. The method according to aspect 16, wherein the RRC release message further indicates that the UE context relocation fails.

[0222] Aspect 18. The method according to aspect 17, wherein: the RRC release message further indicates a random access resource for the UE to send a random access preamble.

[0223] Aspect 19. A method of wireless communication performed by a user equipment (UE), the method comprising: when in an inactive mode, sending a first random access communication to move the UE to a connected mode, wherein the first random access communication includes at least one of uplink (UL) small data transmission (SDT) data or a UL SDT signal; when in the inactive mode, receiving a second random access communication from a first network unit to keep the UE in the inactive mode, wherein the second random access communication includes an indication that at least one of DL non-SDT data or a DL non-SDT signal is scheduled for communication to the UE; and sending a third random access communication based on the indication to move the UE to the connected mode.

[0224] Aspect 20. A method according to aspect 19, wherein: the second random access communication indicates a random access resource; and the sending of the third random access communication comprises sending the third random access communication in at least a portion of the random access resource based on the indication.

[0225] Aspect 21. A first network unit, comprising: a memory device; a transceiver; and a processor, the processor communicating with the memory device and the transceiver, wherein the first network unit is configured to perform the actions according to any one of aspects 1 to 11.

[0226] Aspect 22. A first network unit, comprising: a memory device; a transceiver; and a processor, the processor communicating with the memory device and the transceiver, wherein the first network unit is configured to perform the steps according to any one of aspects 12 to 18.

[0227] Aspect 23. A UE, comprising: a memory device; a transceiver; and a processor, the processor communicating with the memory device and the transceiver, wherein the UE is configured to perform the steps according to any one of aspects 19 to 20.

[0228] Aspect 24. A non-transitory computer-readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first network element to cause the first network element to perform the steps according to any one of aspects 1 to 11.

[0229] Aspect 25. A non-transitory computer readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first network element to cause the first network element to perform the steps according to any one of aspects 12 to 18.

[0230] Aspect 26. A non-transitory computer readable medium having program code recorded thereon, wherein the program code comprises instructions executable by a processor of a first network element to cause the first network element to perform the steps according to any one of aspects 19 to 20.

[0231] Aspect 27. A first network element, comprising means for performing the steps according to any one of aspects 1 to 11.

[0232] Aspect 28. A first network element, comprising means for performing the steps according to any one of aspects 12 to 18.

[0233] Aspect 29. A UE comprising means for performing the steps according to any one of aspects 19 to 20.

[0234] Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0235] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0236] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium, or sent via a computer-readable medium. Other examples and specific implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software, hardware, firmware, hard wiring, or any combination thereof executed by a processor. The features of the implementation functions may also be physically located at different locations, including being distributed so that the various parts of the functions are implemented at different physical locations. In addition, as used herein (including in the claims), as used in a list of items (e.g., followed by a list of items such as "at least one of" or "one or more of"), "or" indicates an inclusive list, so that, for example, a list of [at least one of A, B, or C] means: A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0237] As those skilled in the art will understand by now and depending on the specific application at hand, many modifications, substitutions and changes may be made to the materials, devices, configurations and methods of use of the apparatus of the present disclosure without departing from the spirit and scope of the present disclosure. In view of this, the scope of the present disclosure should not be limited to the specific embodiments illustrated and described herein (as they are only some examples of the present disclosure), but should be fully equivalent to the appended claims and their functional equivalents.

Claims

1. A method of wireless communication performed by a first network element, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving from a second network element an indication of arrival at the second network element of at least one of non-SDT downlink (DL) data or a non-SDT DL signal scheduled for the UE; as well as sending a random access communication to the UE based on the indication to: moving the UE into connected mode; or The UE is maintained in the inactive mode.

2. The method of claim 1, wherein the sending the random access communication comprises sending a radio resource control (RRC) resume message to move the UE into the connected mode.

3. The method according to claim 2, further comprising: UE context information associated with the UE is received from the second network element.

4. The method according to claim 3, wherein: The receiving the UE context information comprises receiving a UE context request response; and The UE context request response includes the indication of the at least one of the non-SDT DL data or the non-SDT DL signal.

5. The method according to claim 3, further comprising: A request for the UE context information is sent to the second network element in response to receiving the indication.

6. The method according to claim 5, wherein: The sending the request for the UE context information comprises sending a pre-encrypted RRC resume message to the second network element; and The method further comprises: receiving the RRC resume message from the second network element, wherein the RRC resume message is encrypted based on a key associated with the second network element; and The sending the RRC resume message includes sending the RRC resume message encrypted based on the key associated with the second network element.

7. The method of claim 1, wherein the sending the random access communication comprises sending a radio resource control (RRC) release message to maintain the UE in the inactive mode.

8. The method of claim 7, wherein the RRC release message indicates the arrival of the non-SDT DL data or the non-SDT DL signal.

9. The method of claim 7, wherein the receiving the indication comprises: The RRC release message is received from the second network element, wherein the RRC release message indicates: UE context relocation failed; as well as The arrival of the non-SDT DL data or the non-SDT DL signal.

10. The method according to claim 9, wherein: The RRC release message indicates random access resources, and The method further comprises: A random access preamble is received from the UE based on the random access resource.

11. The method according to claim 7, further comprising: A paging message is sent to the UE after the sending of the RRC release message, the paging message indicating the arrival of the non-SDT DL data or the non-SDT DL signal.

12. A method of wireless communication performed by a first network element, the method comprising: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving at least one of non-SDT downlink (DL) data or a non-SDT DL signal scheduled for the UE; as well as In response to the receiving of the at least one of the non-SDT DL data or the non-SDT DL signal, sending to a second network element: an indication of the non-SDT DL data or the non-SDT DL signal received at the first network element; and UE context information associated with the UE.

13. The method according to claim 12, wherein: The sending of the UE context information comprises sending a UE context request response; and The UE context request response includes the indication of the at least one of the non-SDT DL data or the non-SDT DL signal.

14. The method according to claim 12, further comprising: receiving a request for the UE context information from the second network element, Wherein the sending of the UE context information is based on the request for the UE context information.

15. The method according to claim 14, wherein: The receiving the request for the UE context information comprises receiving a pre-encrypted Radio Resource Control (RRC) resume message from the second network element, The pre-encrypted RRC resume message indicates the request for the UE context information; and The method further comprises: The RRC resume message encrypted with a key associated with the first network element is sent to the second network element.

16. The method of claim 12, wherein the sending the indication comprises sending a radio resource control (RRC) release message to move the UE into the inactive mode, wherein the RRC release message includes the indication.

17. The method according to claim 16, wherein the RRC release message further indicates that UE context relocation has failed.

18. The method of claim 17, wherein: The RRC release message further indicates a random access resource for the UE to send a random access preamble.

19. A method of wireless communication performed by a user equipment (UE), the method comprising: while in the inactive mode, sending a first random access communication to move the UE into a connected mode, wherein the first random access communication comprises at least one of uplink (UL) small data transmission (SDT) data or a UL SDT signal; while in the inactive mode, receiving a second random access communication from a first network element to maintain the UE in the inactive mode, wherein the second random access communication includes an indication that at least one of DL non-SDT data or a DL non-SDT signal is scheduled for communication to the UE; as well as A third random access communication is sent based on the indication to move the UE into the connected mode.

20. The method of claim 19, wherein: The second random access communication indicates a random access resource; and The sending the third random access communication includes sending the third random access communication in at least a portion of the random access resources based on the indication.

21. A first network unit, the first network unit comprising: Memory devices; Transceiver; and a processor in communication with the memory device and the transceiver, wherein the first network unit is configured to: receiving an uplink (UL) small data transmission (SDT) from a user equipment (UE) in an inactive mode; receiving from a second network element an indication of arrival at the second network element of at least one of non-SDT downlink (DL) data or a non-SDT DL signal scheduled for the UE; as well as sending a random access communication to the UE based on the indication to: moving the UE into connected mode; or The UE is maintained in the inactive mode.

22. The first network element of claim 21, wherein the first network element being configured to send the random access communication comprises the first network element being configured to send a radio resource control (RRC) resume message to move the UE into the connected mode.

23. The first network unit according to claim 22, wherein the first network unit is further configured to: UE context information associated with the UE is received from the second network element.

24. The first network unit according to claim 23, wherein: The first network element being configured to receive the UE context information comprises the first network element being configured to receive a UE context request response; and The UE context request response includes the indication of the at least one of the non-SDT DL data or the non-SDT DL signal.

25. The first network unit according to claim 23, wherein the first network unit is further configured to: A request for the UE context information is sent to the second network element in response to receiving the indication.

26. The first network element according to claim 25, wherein: The first network element being configured to send the request for the UE context information comprises the first network element being configured to send a pre-encrypted RRC resume message to the second network element; and The first network unit is further configured to: receiving the RRC resume message from the second network element, wherein the RRC resume message is encrypted based on a key associated with the second network element; and The first network element is configured to send the RRC resume message encrypted based on the key associated with the second network element.

27. The first network element of claim 21, wherein the first network element being configured to send the random access communication comprises the first network element being configured to send a radio resource control (RRC) release message to maintain the UE in the inactive mode.

28. The first network element of claim 27, wherein the RRC release message indicates the arrival of the non-SDT DL data or the non-SDT DL signal.

29. The first network element according to claim 27, wherein: The first network element is configured to receive the indication including: The first network element is configured to receive the RRC release message from the second network element, wherein the RRC release message indicates: UE context relocation failed; and said arrival of said non-SDT DL data or said non-SDT DL signal; The RRC release message indicates random access resources, and The first network unit is further configured to: A random access preamble is received from the UE based on the random access resource.

30. The first network unit according to claim 27, further comprising: A paging message is sent to the UE after the sending of the RRC release message, the paging message indicating the arrival of the non-SDT DL data or the non-SDT DL signal.

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