Method, device and system for data transmission in energy-saving state

Abstract

Methods, devices, and systems for transmitting data in an energy-saving state are disclosed. In one embodiment, a method performed by a wireless communication device is disclosed. The method includes: entering an energy-saving state; and transmitting uplink data to a wireless communication node while in the energy-saving state.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication, and more particularly, to methods, devices, and systems for transmitting data in an energy-saving state in wireless communication. Background Art

[0002] Today, it is possible to install and activate a device at a street corner that has a camera, some in-vehicle processing capabilities, and is capable of sending information to the authorities. The device can periodically send a small amount of information to the authorities to indicate whether the situation is normal. When the device detects an abnormal event, it sends a high-quality video to the authorities. Similarly, there are such applications on smartphones that often exchange a small amount of data with their server-side. For example, a large amount of information is exchanged only when the user is interested. These devices can be referred to as "devices with variable data", where a large amount of data transmission is expected to occur only occasionally, but the network still needs to support such transmissions.

[0003] In a fifth-generation (5G) new radio (NR) network, each terminal or user equipment (UE) can have various radio resource control (RRC) states (such as RRC_CONNECTED state, RRC_IDLE state, and RRC_INACTIVE state). For example, the RRC_INACTIVE state has been introduced to provide an energy-saving state with control plane latency. For the services mentioned for "devices with variable data", since the device has to report detecting some abnormal situations, a short CP latency is required. Considering its power consumption, the device or UE should be configured to be in the RRC_INACTIVE state. In addition to video transmission in abnormal situations, the device also periodically performs small data transmissions. However, for a UE in the RRC_INACTIVE state in an existing network, whenever the UE has small data to transmit, the UE has to first enter the RRC_CONNECTED state and then initiate the data transmission, which causes a significant signaling consumption and cannot support an efficient signaling mechanism.

[0004] Therefore, the existing systems and methods for handling data transmission in wireless communication are not entirely satisfactory. Summary of the Invention

[0005] Exemplary embodiments disclosed herein relate to solving problems associated with one or more problems existing in the prior art and providing other features that are readily apparent when the following detailed description is considered in conjunction with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of illustration and not limitation, and it will be apparent to those of ordinary skill in the art who read this disclosure that various modifications can be made to the disclosed embodiments that still fall within the scope of this disclosure.

[0006] In one embodiment, a method performed by a wireless communication device is disclosed. The method includes: entering an energy-saving state; and transmitting uplink data to a wireless communication node while in the energy-saving state.

[0007] In another embodiment, a method performed by a wireless communication node is disclosed. The method includes: receiving uplink data from the wireless communication device while the wireless communication device is in an energy-saving state.

[0008] In various embodiments, a wireless communication node is disclosed that is configured to perform the method disclosed in a certain embodiment.

[0009] In yet another embodiment, a wireless communication device is disclosed that is configured to perform the method disclosed in a certain embodiment.

[0010] In additional embodiments, a non-transitory computer-readable medium is disclosed having computer-executable instructions stored thereon for the method disclosed in a certain embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The various exemplary embodiments of the present disclosure are described in detail below with reference to the following drawings. The drawings are provided for illustrative purposes only and depict only the exemplary embodiments of the present disclosure to facilitate the reader's understanding of the present disclosure. Therefore, the drawings should not be considered as limiting the breadth, scope, or applicability of the present disclosure. It should be noted that these drawings are not necessarily drawn to scale for clarity and ease of illustration.

[0012] Figure 1 An exemplary communication network is shown in which the techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure.

[0013] Figure 2 A block diagram of a base station (BS) is shown, in accordance with some embodiments of the present disclosure.

[0014] Figure 3 A flowchart of a method for data transmission in an energy-saving state performed by a BS is shown, in accordance with some embodiments of the present disclosure.

[0015] Figure 4 A block diagram of a user equipment (UE) is shown, in accordance with some embodiments of the present disclosure.

[0016] Figure 5 A flowchart of a method for data transmission in an energy-saving state performed by a UE is shown, in accordance with some embodiments of the present disclosure.

[0017] Figure 6 An exemplary method for data transmission using a security key in an energy-saving state is shown, in accordance with an embodiment of the present disclosure.

[0018] Figure 7 An exemplary method of data transmission using a two-step random access channel (RACH) procedure in an energy-saving state according to an embodiment of the present disclosure is shown.

[0019] Figure 8 An exemplary method of data transmission using a four-step RACH procedure in an energy-saving state according to an embodiment of the present disclosure is shown. Detailed implementation manners

[0020] Various exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings so that those of ordinary skill in the art can make and use the present disclosure. It will be apparent to those of ordinary skill in the art that various changes or modifications to the examples described herein can be made without departing from the scope of the present disclosure after reading the present disclosure. Therefore, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and / or hierarchy of steps in the methods disclosed herein are merely exemplary methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be rearranged while remaining within the scope of the present disclosure. Therefore, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in an exemplary order, and the present disclosure is not limited to the specific order or hierarchy presented unless otherwise expressly stated.

[0021] Typical wireless communication networks include one or more base stations (commonly referred to as "BS") each providing a geographical radio coverage area, and one or more wireless user devices (commonly referred to as "UE") that can send and receive data within the radio coverage area. As sensors and monitoring devices are deployed more widely, there will be a need to support devices that send data packets, the size of which ranges from a few bits for status updates to large data such as streaming video. The network should have the flexibility to provide efficient services to devices regardless of when they send data and how much data is sent in a given transmission. The network should be efficient for both frequent and infrequent short data bursts and large amounts of data (such as video data) because equipping a device with two separate modems for two technologies would increase the complexity of the device.

[0022] According to various requirements, the 5G system should efficiently and flexibly handle low-throughput short data bursts and high-throughput data transmissions (such as streaming video) from the same device; should support an efficient signaling mechanism (e.g., signaling is less than the payload); and should reduce the security signaling overhead required for short data burst transmissions without reducing the security protection provided by previous systems. To better support devices with various data and meet the above requirements, this teaching discloses a system and method for data transmission in an energy-saving state without state transition. The energy-saving state can be the RRC_INACTIVE state, the RRC_IDLE state, or another state in which the UE is not required to monitor the Physical Downlink Control Channel (PDCCH) based on the Cell Radio Network Temporary Identifier (C-RNTI) and / or is not required to maintain uplink (UL) synchronization unless a state transition occurs.

[0023] Specifically, to support short data bursts, the disclosed system has the ability to operate in a connectionless mode, in which, when sending a small amount of data, there is no need to establish and tear down a connection. Therefore, the disclosed system will accept data transmissions without the long and signaling-intensive bearer establishment and authentication processes. As a result, the system will avoid negatively affecting the device's battery life and using more signaling resources than the actual data transmission resources. When a large amount of data (such as video) needs to be sent, the same device may establish a connection.

[0024] Considering that a UE in an energy-saving state does not have UL synchronization, a UE in the RRC_INACTIVE state or the RRC_IDLE state cannot directly use the normal Physical Uplink Control Channel (PUSCH) for transmission, including grant-free transmission. To initiate UL data transmission in an energy-saving state, a Random Access Channel (RACH) procedure or a procedure similar to RACH can be used. That is, UL data transmission in the RRC_INACTIVE state should be initiated by RACH or a procedure similar to RACH.

[0025] In one embodiment, for data transmission in an energy-saving state without state transition, the following operations can be performed. First, the UE receives the configuration of "data transmission in an energy-saving state without state transition" from the network side through system information and / or RRC dedicated signaling. Second, once a UE in an energy-saving state has data to send, the UE initiates a RACH procedure or a grant-free transmission and includes the data packet in the payload of the RACH procedure or the grant-free transmission to send the uplink data packet.

[0026] The methods disclosed in this teaching can be implemented in a wireless communication network, where the BS and the UE can communicate with each other via a communication link, e.g., via a downlink radio frame from the BS to the UE or via an uplink radio frame from the UE to the BS. In various embodiments, the BS in this disclosure may be referred to as the network side and may include or be implemented as a next-generation node B (gNB), an E-UTRAN node B (eNB), a transmit / receive point (TRP), an access point (AP), etc.; while the UE in this disclosure may be referred to as a terminal and may include or be implemented as a mobile station (MS), a station (STA), etc. The BS and the UE may be described herein as non-limiting examples of a "wireless communication node" and a "wireless communication device", respectively; according to various embodiments of this disclosure, the BS and the UE may practice the methods disclosed herein and are capable of wireless and / or wired communication.

[0027] Figure 1 FIG. 100 shows an exemplary communication network in which the techniques disclosed herein may be implemented according to an embodiment of the present disclosure. As Figure 1 shown, the exemplary communication network 100 includes a base station (BS) 101 and a plurality of UEs, UE 1 110, UE 2 120... UE 3 130, where the BS 101 may communicate with the UEs according to a wireless protocol. Each UE may enter an energy-saving state in which the UE does not have uplink synchronization. When the UE determines that there is some data to send during the energy-saving state, the UE may initiate a process of accessing an application or service via the network 100 and send uplink data to the BS 101 while the UE is still in the energy-saving state without any state transition.

[0028] Figure 2 FIG. 200 shows a block diagram of a base station (BS) 200 according to some embodiments of the present disclosure. The BS 200 is an example of a device that may be configured to implement the various methods described herein. As Figure 2 shown, the BS 200 includes a housing 240 that contains a system clock 202, a processor 204, a memory 206, a transceiver 210 including a transmitter 212 and a receiver 214, a power module 208, an uplink data analyzer 220, a UE status configurator 222, a UE context acquirer 224, a security key determiner 226, a temporary activity timer controller 228, and a packet data convergence protocol (PDCP) count controller 229.

[0029] In this embodiment, system clock 202 provides a timing signal to processor 204 to control the timing of all operations of BS 200. Processor 204 controls the general operation of BS 200 and may include one or more processing circuits or modules, such as a central processing unit (CPU) and / or a general-purpose microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a controller, a state machine, gated logic, discrete hardware components, a dedicated hardware finite state machine, or any other suitable combination of circuits, devices, and / or structures that can perform calculations or other manipulations of data.

[0030] Memory 206, which can include read-only memory (ROM) and random access memory (RAM) simultaneously, can provide instructions and data to processor 204. A portion of memory 206 may also include non-volatile random access memory (NVRAM). Processor 204 generally performs logical and arithmetic operations based on program instructions stored in memory 206. The instructions (also referred to as software) stored in memory 206 can be executed by processor 204 to perform the methods described herein. Processor 204 and memory 206 together form a processing system that stores and executes software. As used herein, "software" refers to any type of instruction that can configure a machine or device to perform one or more desired functions or processes, whether referred to as software, firmware, middleware, microcode, etc. The instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable code format). When executed by one or more processors, the instructions cause the processing system to perform the various functions described herein.

[0031] Transceiver 210, which includes transmitter 212 and receiver 214, allows BS 200 to send data to and receive data from remote devices (e.g., UEs or another BS). Antenna 250 is generally attached to housing 240 and electrically coupled to transceiver 210. In various embodiments, BS 200 includes (not shown) multiple transmitters, multiple receivers, and multiple transceivers. In one embodiment, antenna 250 is replaced by a multi-antenna array 250, which can form multiple beams, each beam pointing in a different direction. Transmitter 212 can be configured to wirelessly transmit packets with different packet types or functions, such packets being generated by processor 204. Similarly, receiver 214 is configured to receive packets with different packet types or functions, and processor 204 is configured to process packets of multiple different packet types. For example, processor 204 can be configured to determine the packet type and accordingly process the packet and / or fields of the packet.

[0032] In wireless communication, when the UE is in a connected state or an energy-saving state, the BS 200 can receive data from the UE. For example, in this example, the uplink data analyzer 220 can receive uplink data from the UE via the receiver 214 when the UE is in an energy-saving state. According to various embodiments, the energy-saving state can be at least one of the following: an inactive state; an idle state; a state in which the UE does not maintain uplink synchronization; and a state in which the UE does not monitor the physical downlink control channel (PDCCH) based on a cell radio network temporary identifier (C-RNTI).

[0033] In one embodiment, the uplink data analyzer 220 analyzes uplink data received based on at least one of the following: grant-free transmission; and the payload of the random access procedure of the BS 200. The payload refers to at least one of the following: in the first step of a two-step random access channel (RACH) procedure, the payload sent after the preamble; in the third step of a four-step RACH procedure, the media access control (MAC) protocol data unit (PDU) sent in the message; in a procedure similar to RACH, the payload sent after the preamble; and the payload sent together with the demodulation reference signal (DMRS). The payload can include information related to at least one of the following: the identification (ID) of the UE; at least one data packet of the uplink data; a buffer status report (BSR); a power headroom report (PHR); a flag indicating the reason for the random access procedure; a flag indicating whether a random access procedure is initiated for data transmission without a state transition; a radio resource control (RRC) message; and the data packet included in the RRC message. The uplink data can be included in at least one of the following: a media access control (MAC) service data unit (SDU) for which a MAC sub-header is allocated to indicate the logical channel to which the uplink data belongs; and at least one radio resource control (RRC) message, which is used as at least one of the following: a bit string, an octet string, and a container.

[0034] The UE state configurator 222 in this example generates and sends configuration information related to the energy-saving state to the UE via the transmitter 212, through at least one of system information and dedicated radio resource control (RRC) signaling. The configuration information includes information related to at least one of the following: the configuration of random access resources; the configuration of grant-free transmission; an indicator indicating whether data transmission in the energy-saving state is supported and / or allowed; for a regional scope including multiple cells, the configuration of whether data transmission in the energy-saving state is supported and / or allowed in each of the multiple cells; and the configuration related to the selection between data transmission after a state transition and data transmission in the energy-saving state without a state transition.

[0035] In one embodiment, the UE state configurator 222 configures data transmission in an energy-saving state allowing stateless transition based on at least one of the following: a first indicator in system information indicating whether data transmission in an energy-saving state allowing stateless transition is permitted in a cell; a second indicator in dedicated signaling indicating a cell list of at least one cell including data transmission in an energy-saving state allowing stateless transition; a third indicator indicating whether data transmission in an energy-saving state allowing stateless transition is permitted in a public land mobile network; a fourth indicator indicating whether data transmission in an energy-saving state allowing stateless transition is permitted in a tracking area; a fifth indicator indicating whether data transmission in an energy-saving state allowing stateless transition is permitted in a radio access network (RAN) notification area; a plurality of indicators, each indicator corresponding to one of a plurality of cells in a regional scope, where each indicator in the plurality of indicators indicates whether data transmission in an energy-saving state is permitted in a corresponding cell; a separate indicator related to the energy-saving state; and a common indicator related to a plurality of energy-saving states including the energy-saving state.

[0036] In one embodiment, the UE state configurator 222 may determine to keep the UE in an energy-saving state while transmitting uplink data based on at least one of the following: the buffer size of the uplink data is less than a threshold; the uplink data is related to a traffic type for which data transmission in an energy-saving state allowing or not allowing stateless transition is permitted, where the traffic type refers to at least one of the following: a logical channel, a logical channel group, a protocol data unit (PDU) session, or a quality of service (QoS) flow; the total buffer size of data related to at least one traffic for which data transmission allowing stateless transition is permitted is less than a threshold; and an indication to the UE. In another embodiment, the BS 200 provides parameters to the UE so that the UE makes a decision on whether to keep in an energy-saving state while transmitting uplink data.

[0037] In one embodiment, the UE context acquirer 224 determines that there is no context of the UE at the media access control (MAC) layer of the BS 200 or there is no such context at the DU of the BS 200. The UE context acquirer 224 may then perform at least one of the following operations on the uplink data: buffer the uplink data and send an indication to a higher layer, buffer the uplink data and send an indication to the UE, discard the uplink data, and forward the uplink data to a different node having the context of the UE. In one embodiment, "no context exists" means that no UE context is identified or found based on the UE ID received from the UE and the data.

[0038] In another embodiment, the UE context acquirer 224 determines that the context of the UE does not exist in the media access control (MAC) layer of the distributed unit (DU) acting as the central unit (CU) of the BS 200. Then, the UE context acquirer 224 may perform at least one of the following operations on the uplink data: send a message to the CU to request the context of the UE, buffer the uplink data until the context is established, and forward the uplink data to the CU through a non-UE-specific common tunnel.

[0039] In one embodiment, the uplink data is received based on the security protection key of the uplink data. The security key determiner 226 may determine what the key is. For example, the security key determiner 226 may determine that the key is the same as the key used by the UE before entering the energy-saving state.

[0040] In one embodiment, the uplink data is received based on the first security protection key of the uplink data. The security key determiner 226 may determine that the first key is different from the second key used by the UE before entering the energy-saving state.

[0041] The first key may be used after at least one of the following: a downlink (DL) dedicated control channel (DCCH) message that triggers a state transition, an uplink (UL) common control channel (CCCH) message that requests a state transition, a UL DCCH message that requests a state transition, any DL DCCH message, any UL CCCH message, an indicator in the packet data convergence protocol (PDCP) header indicating the use of the first key, and an indicator in the radio resource control (RRC) message indicating the use of the first key.

[0042] In one embodiment, the uplink data analyzer 220 may receive and analyze additional data from the UE while the UE is in a time period referred to as a temporary time period. The UE in the temporary time period monitors the physical downlink control channel (PDCCH) through the identity (ID) of the UE without a state transition in the radio resource control (RRC) layer. The temporary activity timer controller 228 may control and / or determine the length of the temporary time period based on a timer. The timer is configured based on at least one of the following: system information; dedicated RRC signaling; a message in the second step of a two-step random access channel (RACH) procedure; a message and / or a MAC control element (MAC CE) and / or downlink control information (DCI) in the second step of a four-step RACH procedure; and a message and / or a MAC CE and / or DCI in the fourth step of a four-step RACH procedure. For example, the timer may be started in response to at least one of the following: the UE's first reception of a message in the second step of a two-step RACH procedure, the UE's second reception of a message in the fourth step of a four-step RACH procedure, a first offset after the first reception, and a second offset after the second reception. The timer may be restarted when the UE receives the PDCCH through the UE's ID. The UE will exit the temporary time period in response to the timer expiring.

[0043] In this example, the PDCP count controller 229 instructs the UE to maintain the same packet data convergence protocol (PDCP) count value during an energy-saving state based on at least one of the following: a first indicator in the system information indicating whether the PDCP count value should be reset; and a second indicator in a dedicated RRC message indicating whether the PDCP count value should be reset. In an alternative solution, the UE may maintain the PDCP count value unless a state transition is triggered and / or initialized. In another alternative, once data transmission using a stateless transition is performed, the UE may maintain the PDCP count value.

[0044] The power module 208 may include a power source such as one or more batteries and a power regulator to provide regulated power to each of the above modules in Figure 2 In some embodiments, if the BS 200 is coupled to a dedicated external power source (e.g., a wall power outlet), the power module 208 may include a transformer and a power regulator.

[0045] The various modules discussed above are coupled together through a bus system 230. The bus system 230 may include a data bus and, for example, includes a power bus, a control signal bus, and / or a status signal bus in addition to the data bus. It should be understood that the modules of the BS 200 may be operably coupled to each other using any suitable technology and medium.

[0046] Although in Figure 2Multiple separate modules or components are shown, however, one of ordinary skill in the art will understand that one or more modules may be combined or implemented jointly. For example, processor 204 may implement not only the functions described above with respect to processor 204, but also the functions described above with respect to uplink data analyzer 220. Conversely, Figure 2 Each of the modules shown may be implemented using multiple separate components or elements.

[0047] Figure 3 A flowchart of method 300 for data transmission in an energy-saving state performed by a BS (e.g., Figure 2 BS 200 in) according to some embodiments of the present disclosure is shown. At operation 302, the BS configures an energy-saving state for the UE in which the UE does not need to maintain uplink synchronization. At operation 304, while the UE is in the energy-saving state, the BS receives and analyzes uplink data from the UE. When there is no UE context at the BS, the BS optionally obtains the UE context of the UE at operation 306. At operation 308, the BS determines a security key for security protection of the uplink data of the UE. At operation 310, the BS determines a time period when the UE is in a temporary time period to enable additional uplink data transmission without a state transition in the RRC layer. Figure 3 The order of the steps shown may be changed according to different embodiments of the present disclosure.

[0048] Figure 4 A block diagram of UE 400 according to some embodiments of the present disclosure is shown. UE 400 is an example of a device that may be configured to implement the various methods described herein. As Figure 4 shown, UE 400 includes a housing 440 that contains a system clock 402, a processor 404, a memory 406, a transceiver 410 including a transmitter 412 and a receiver 414, a power module 408, a status controller 420, a data packet generator 422, a status configuration analyzer 424, a security key controller 426, a temporary activity timer controller 428, and a PDCP count controller 429.

[0049] In this embodiment, the system clock 402, the processor 404, the memory 406, the transceiver 410, and the power module 408 operate in a manner similar to the system clock 202, the processor 204, the memory 206, the transceiver 210, and the power module 208 in BS 200. An antenna 450 or a multi-antenna array 450 is typically attached to the housing 440 and electrically coupled to the transceiver 410.

[0050] The state controller 420 in this example can control the UE 400 to enter an energy-saving state. According to various embodiments, the energy-saving state can be at least one of the following: an inactive state; an idle state; a state in which the UE 400 does not maintain uplink synchronization; and a state in which the UE 400 does not monitor the physical downlink control channel (PDCCH) based on a cell radio network temporary identifier (C-RNTI).

[0051] The data packet generator 422 in this example generates and transmits uplink data to the BS via the transmitter 412 while the UE is in the energy-saving state. The uplink data can be transmitted based on at least one of the following: grant-free transmission; and the payload of the random access procedure of the BS. The payload refers to at least one of the following: the payload transmitted after the preamble in the first step of a two-step random access channel (RACH) procedure; the media access control (MAC) protocol data unit (PDU) transmitted in the message in the third step of a four-step RACH procedure; the payload transmitted after the preamble in a procedure similar to RACH; and the payload transmitted together with the demodulation reference signal (DMRS). The payload can include information related to at least one of the following: the identification (ID) of the UE; at least one data packet of the uplink data; a buffer status report (BSR); a power headroom report (PHR); a flag indicating the reason for the random access procedure; a flag indicating whether a random access procedure is initiated for data transmission without a state transition; a radio resource control (RRC) message; and the data packet included in the RRC message. In one embodiment, the uplink data includes at least one of the following: a media access control (MAC) service data unit (SDU) for which a MAC sub-header is allocated to indicate the logical channel to which the uplink data belongs; and at least one radio resource control (RRC) message that serves as at least one of the following: a bit string, an octet string, and a container.

[0052] The state configuration analyzer 424 in this example receives configuration information related to the energy-saving state from the BS through at least one of system information and dedicated radio resource control (RRC) signaling. The state configuration analyzer 424 can analyze the configuration information to determine that it includes information related to at least one of the following: the configuration of random access resources; the configuration of grant-free transmission; an indicator indicating whether data transmission in the energy-saving state is supported and / or allowed; for a regional scope including multiple cells, the configuration regarding whether data transmission in the energy-saving state is supported and / or allowed in each of the multiple cells; and the configuration related to the selection between data transmission after a state transition and data transmission in the energy-saving state without a state transition.

[0053] The status configuration analyzer 424 may send the analyzed information to the status controller 420 to control the status of the UE. In one example, the status controller 420 may determine to allow data transmission in an energy-saving state with stateless transition based on at least one of the following: a first indicator in system information indicating whether data transmission in an energy-saving state with stateless transition is allowed in the cell; a second indicator in dedicated signaling indicating a cell list including at least one cell that allows data transmission in an energy-saving state with stateless transition; a third indicator indicating whether data transmission in an energy-saving state with stateless transition is allowed in the public land mobile network; a fourth indicator indicating whether data transmission in an energy-saving state with stateless transition is allowed in the tracking area; a fifth indicator indicating whether data transmission in an energy-saving state with stateless transition is allowed in the radio access network (RAN) notification area; and a plurality of indicators, each corresponding to one of a plurality of cells in a regional scope, where each of the plurality of indicators indicates whether data transmission in an energy-saving state is allowed in the corresponding cell.

[0054] In another example, the status controller 420 may determine to allow data transmission in an energy-saving state with stateless transition based on at least one of the following: a separate indicator related to the energy-saving state; and a common indicator related to a plurality of energy-saving states including the energy-saving state. In yet another example, the status controller 420 may determine to keep the UE 400 in an energy-saving state while transmitting uplink data based on at least one of the following: the cache size of the uplink data is less than a threshold; the uplink data is related to a traffic type for which data transmission in an energy-saving state with or without stateless transition is allowed, where the traffic type refers to at least one of the following: logical channel, logical channel group, protocol data unit (PDU) session, or quality of service (QoS) flow; the total cache size of data related to at least one traffic for which data transmission with stateless transition is allowed is less than a threshold; and an indication from the BS.

[0055] In one embodiment, uplink data is transmitted based on a security protection key for the uplink data. The security key controller 426 may determine whether to generate a new key or continue to use an old key for uplink transmission. The security key controller 426 in this example may generate a key. For example, the key may be the same as a previously generated key used by the UE before entering the energy-saving state.

[0056] In one embodiment, the first key for security protection of uplink data is used to send uplink data. The security key controller 426 in this example can generate the first key. For example, the first key can be different from the second key used by the UE before entering the energy-saving state. The first key can be generated and / or used in response to at least one of the following: receiving a downlink (DL) dedicated control channel (DCCH) message that triggers a state transition, sending an uplink (UL) common control channel (CCCH) message that requests a state transition, sending a UL DCCH message that requests a state transition, receiving any DL DCCH message, sending any UL CCCH message, an indicator in the packet data convergence protocol (PDCP) header indicating the use of the first key, and an indicator in the radio resource control (RRC) message indicating the use of the first key.

[0057] The data packet generator 422 can determine and generate additional data to be sent at the radio resource control (RRC) layer during the energy-saving state. In one example, when the additional data cannot fit into the payload, the state controller 420 can control the UE 400 to enter a time period called the temporary time period. The UE in the temporary time period monitors the physical downlink control channel (PDCCH) via the UE's identity (ID) without a state transition at the RRC layer. Then, the data packet generator 422 can send the additional data via the transmitter 412 while the UE 400 is in the temporary time period.

[0058] The temporary activity timer controller 428 in this example can control the length of the temporary time period based on a timer. The timer can be configured based on at least one of the following: system information; dedicated RRC signaling; a message in the second step of a two-step random access channel (RACH) procedure; a message in the second step of a four-step RACH procedure; and a message in the fourth step of a four-step RACH procedure. In one example, the temporary activity timer controller 428 can start the timer in response to at least one of the following: the first reception of a message in the second step of a two-step RACH procedure, the second reception of a message in the fourth step of a four-step RACH procedure, a first offset after the first reception, and a second offset after the second reception. In another example, the temporary activity timer controller 428 restarts the timer when a PDCCH is received via the UE's ID. In response to the timer expiration, the state controller 420 can control the UE 400 to exit the temporary time period.

[0059] The PDCP count controller 429 in this example controls the packet data convergence protocol (PDCP) count value to remain the same during the energy-saving state based on at least one of the following: a first indicator in the system information indicating whether the PDCP count value should be reset; and a second indicator in the dedicated RRC message indicating whether the PDCP count value should be reset.

[0060] The various modules discussed above are coupled together through a bus system 430. The bus system 430 may include a data bus and, for example, include a power bus, a control signal bus, and / or a status signal bus in addition to the data bus. It should be understood that the modules of the UE 400 may be operably coupled to each other using any suitable technology and medium.

[0061] Although Figure 4 a plurality of separate modules or components are shown, one or more modules may be combined or jointly implemented, as will be understood by those of ordinary skill in the art. For example, the processor 404 may implement not only the functions described above with respect to the processor 404 but also the functions described above with respect to the status controller 420. Conversely, Figure 4 each module shown may be implemented using a plurality of separate components or elements.

[0062] Figure 5 FIG. shows a flowchart of a method 500 for data transmission in an energy-saving state by a UE (e.g., Figure 4 the UE 400 in ) according to some embodiments of the present disclosure. At operation 502, the UE enters an energy-saving state in which the UE does not need to maintain uplink synchronization. At operation 504, the UE generates a security key for protecting uplink data security. At operation 506, the UE maintains the same packet data convergence protocol (PDCP) count value during the energy-saving state. At operation 508, while the UE is in the energy-saving state, the UE transmits uplink data to the BS. At operation 510, the UE enters a time period based on a timer for additional uplink data transmission with a stateless transition at the RRC layer. This time period may be referred to as a temporary time period. Figure 5 The order of the steps shown may be changed according to different embodiments of the present disclosure.

[0063] Various embodiments of the present disclosure will now be described in detail below. Note that the features of the embodiments and examples in the present disclosure may be combined with each other in any way without conflict.

[0064] According to various embodiments of the present disclosure, the following steps may be used as a baseline for data transmission in an energy-saving state with a stateless transition. In step 1: The UE receives a configuration for "data transmission in an energy-saving state with a stateless transition" from the network side (NW) through system information and / or RRC dedicated signaling. In step 2: When the UE in the energy-saving state has data to transmit, the UE initiates a RACH procedure or a grant-free transmission and includes the data packet in the payload of the RACH procedure or the grant-free transmission to transmit uplink data.

[0065] In the first embodiment, since "data transmission in the energy-saving state without state transition" can only be performed in a cell that permits (e.g., supports and permits) "data transmission in the energy-saving state without state transition", the UE needs to know whether data transmission without state transition is permitted within a cell. To configure this information, the following alternative solutions are proposed.

[0066] In Alternative 1, an indicator provided per cell in the system information is proposed. The system information may include an indicator for indicating whether "data transmission in the energy-saving state without state transition" is permitted in the cell. If the indicator is set to true, the UE can only initiate "data transmission in the energy-saving state without state transition". In one example, an indicator can be introduced in the system information. The indicator can be provided per cell, per Public Land Mobile Network (PLMN), or per RAN notification area.

[0067] In Alternative 2, an area provided by a cell list is proposed. The cell list can be configured for the UE through dedicated signaling, and "data transmission in the energy-saving state without state transition" is permitted in the cells included in the cell list. That is, only when a cell is included in the cell list, the UE is permitted to initiate "data transmission in the energy-saving state without state transition". The dedicated RRC signaling can be the signaling used to drive the UE into the energy-saving state, or the dedicated RRC signaling before the UE enters the energy-saving state. In one example, a cell list can be introduced in the RRC signaling to indicate in which cells "data transmission in the energy-saving state without state transition" is permitted.

[0068] In Alternative 3, an indicator provided per cell in the RAN notification area is proposed. The area range of the RAN notification area can be provided by a cell list. For each cell in the cell list of the RAN notification area, an indicator can be introduced to indicate whether "data transmission in the energy-saving state without state transition" is permitted in that cell. In one example, an indicator can be introduced in the cell information of the cell list used to configure the area range of the RAN notification area. The indicator is used to indicate whether "data transmission in the energy-saving state without state transition" is permitted in that cell.

[0069] For the above alternatives, if multiple PLMNs or multiple TAs or RAN notification areas are supported in a cell, indicators can also be provided per PLMN or per TA or per RAN notification area. For all of the above alternatives, separate indicators and / or cell lists can be provided for different power saving states, or a common indicator and / or cell list can be provided for one or more power saving states. For example, separate indicators can be provided for "data transmission under RRC_INACTIVE without state transition" and "data transmission under RRC_IDLE without state transition"; or a common indicator can be provided for both RRC_INACTIVE and RRC_IDLE (i.e., the common indicator applies to both power saving states).

[0070] In a second embodiment, consider how to determine whether data transmission should be handled via "data transmission without state transition" or "data transmission with state transition" (i.e., handle state transition before data transmission). Even if "data transmission without state transition" is allowed in a cell, since a UE can initiate data transmission with or without state transition (e.g., from a power saving state to the RRC CONNECTED state), some rules can be defined for the choice between data transmission with state transition and data transmission without state transition. To determine this, both NW-based solutions and UE-based solutions can be considered.

[0071] For the UE-based solution, the following rules or combinations of the following rules can be considered. The first rule is based on the buffer size of UE-side data. For this purpose, a buffer size threshold should be configured for the UE via system information or dedicated signaling. The buffer size threshold can be provided per UE, per logical channel, per logical channel group, per data radio bearer (DRB), per protocol data unit (PDU) session, or per quality of service (QoS) flow. Once the buffer on the UE side is less than (less than or equal to) the threshold, the UE is allowed to initiate "data transmission under RRC_INACTIVE without state transition"; otherwise, the UE should initiate a state transition first. For cases where the buffer size is defined per logical channel or logical channel group, if the buffer is not included for the logical channel or logical channel group, the data buffered in that logical channel or logical channel group will initiate data transmission with state transition. That is, after directly triggering the state transition process, the UE will send an RRC establishment request or an RRC resume request message to the NW to initiate the state transition. For cases where the buffer size is defined per UE and no buffer size is configured, "data transmission under RRC_INACTIVE without state transition" is not allowed, and the UE should always initiate a state transition first.

[0072] Another rule is based on the logical channel ID (or DRB ID, QoS flow ID, PDU session ID) for which there is available data in the buffer. To achieve this, an indicator provided per logical channel or per logical channel group or per DRB or per PDU session or per QoS flow (e.g., the indicator is used to indicate whether stateless transition data transmission is allowed for the logical channel or logical channel group, etc.) or a bitmap for the logical channel or logical channel group or DRB or PDU session or QoS flow (e.g., the bitmap is used to indicate which logical channel or logical channel group or DRB or PDU session or QoS flow is allowed for stateless transition data transmission) should be configured for the UE in dedicated signaling. With this indicator, once there is buffered data on the UE side and all (or any) logical channels / logical channel groups / DRBs / PDU sessions / QoS flows with buffered data are allowed to initiate "data transmission under RRC_INACTIVE with stateless transition", the UE is allowed to initiate "data transmission under RRC_INACTIVE with stateless transition". Alternatively, with this indicator, once there is buffered data on the UE side and any logical channels / logical channel groups / DRBs / PDU sessions / QoS flows with buffered data are not allowed to initiate "data transmission under RRC_INACTIVE with stateless transition", the UE should first initiate a state transition.

[0073] Another rule is based on the combination of the logical channel / logical channel / DRB / PDU session / QoS flow and the buffer size. For example, the new rule can be based on the total buffer size and / or threshold for the logical channel or logical channel group or DRB or PDU session or QoS flow that allows stateless transition data transmission.

[0074] In the NW-based solution, the UE can always include in the payload of the RACH procedure an RRC message that can trigger a state transition. It is up to the NW to decide whether to initiate a state transition or allow the UE to handle data transmission in the power-saving state or keep the UE in the power-saving state. Through the RRC message, the buffer status information can also be included in the payload. The NW can make a decision based on the buffer information.

[0075] In the third embodiment, the "payload of the RACH procedure" in step 2 above can be defined according to various examples. In one example, the RACH procedure mentioned above can be a two-step RACH, a four-step RACH, or a RACH-like procedure. The meaning of the "payload of the RACH procedure" can be one of the following: for a two-step RACH procedure, the payload refers to the payload sent through Message (Msg) 1 in step 1 after the preamble; for a four-step RACH procedure, the payload refers to the MAC PDU sent through Msg 3; for a RACH-like method, the payload can be the payload sent after a certain preamble or the payload sent together with the DMRS.

[0076] In the fourth embodiment, information included in the payload of the RACH procedure or grant-free transmission is proposed. For a RACH or RACH-like procedure used to initiate UL transmission in an energy-saving state, the following information can be included in the payload part. First, the payload can include an I-RNTI or some other ID that can be used to identify the UE. The I-RNTI or "UE ID" can be included as a header / sub-header of the MAC-CE or MAC PDU. The payload can also include a data packet. The data packet can be included as a MAC SDU. For the MAC SDU, a MAC sub-header is allocated, which includes at least one logical channel ID to indicate which logical channel the data packet belongs to.

[0077] The payload can also include a buffer status report (BSR), which can be included as a MAC CE; a power headroom report (PHR), which can be included as a MAC CE; an RRC message; and / or a data packet included as a container in the RRC message. The payload can also include the reason or type flag of the random access (RA) procedure, from which the NW can identify whether the RA procedure is initiated for data transmission without a state transition. The NW can identify the reason for the RA procedure based on the I-RNTI. For example, if the I-RNTI is included as a MAC CE, the NW knows that the RA is initiated for data transmission without a state transition.

[0078] Once the NW receives the payload, the MAC entity on the NW side can identify the UE based on the I-RNTI and deliver the MAC PDU to the RLC / PDCP entity based on the logical channel ID. To achieve this, a common MAC function is required in the MAC entity to implement the distribution of the MAC PDU. Once the NW detects a MAC PDU with an I-RNTI MAC CE and there is no UE context for this UE in the MAC, the NW can establish a UE context for this UE in the MAC.

[0079] In one embodiment, the data packet may be included as a MAC SDU or as part of an RRC message. In one example, the data packet will be included as a MAC SDU. For a MAC SDU, a MAC sub-header is allocated, which includes at least one logical channel ID to indicate which logical channel the data packet belongs to. In another example, the data packet will be included in one (or more) RRC messages as a bit string or an octet string or an RRC container. For each bit string, octet string, or RRC container, one (or more) MAC PDUs, RLC PDUs, PDCP PDUs, SDAP PDUs may be included.

[0080] In the fifth embodiment, once the NW receives the payload mentioned in step 2, the NW can identify the UE based on the I-RNTI or some other "UE ID" included in the payload.

[0081] From the perspective of the MAC layer, if there is a UE context on the MAC entity, the NW can perform demultiplexing processing and forward the data packet to the corresponding RLC. If there is no UE context on the MAC entity, the NW can: cache the data packet until the UE context is established; or forward the data packet to another NW entity where there is a UE context.

[0082] In the first example, if there is no UE context on the NW side, the NW can cache the packet and send an indicator to a higher layer. For example, the NW can cache the data packet and process it after the UE context is established; send an indication to a higher layer (e.g., from MAC to a higher layer such as RRC) to notify that a UE identified by the I-RNTI or some other type of UE ID has received the data packet. With this indicator, the higher layer (e.g., RRC) can trigger a context acquisition process to establish the context, depending on the implementation of the NW, or send an indication to the UE to first trigger a state transition.

[0083] In the second example, if there is no UE context on the NW side, the NW can cache the data and send a failure indication to the UE. For example, the NW can cache the data packet and process it after the UE context is established. A failure indication can be sent to the UE via an RRC message or a MAC CE or a physical layer command (e.g., DCI). Once the failure indication is received, the UE can initiate a state transition process (e.g., via an RRC Resume Request message sent to the NW), during which the UE context will be established on the NW side.

[0084] In the above two examples, a timer can be maintained on the NW side. The timer can be started after receiving a data packet. If the UE context cannot be established before the timer expires, the NW can discard the buffered data.

[0085] In one example, if the UE context does not exist on the NW side, the NW can discard the received data packet. The NW can send an indication to a higher layer, such as notifying a UE identified by the UE ID that a data packet has been received; and / or send a message to the UE to trigger a state transition. The message can be an L3 RRC message or an L2 MAC CE. In another example, if the UE context does not exist on the NW side, the NW can forward the packet to the anchor node regardless of whether the UE context can be found there.

[0086] The NW can include a DU (Distributed Unit) and a CU (Central Unit). If the UE context exists on the DU, the DU can perform demultiplexing processing through the GPRS (General Packet Radio Service) tunneling protocol (GTP) tunnel of the corresponding DRB and forward the data packet to the CU. If the UE context does not exist on the DU, the DU can send a message to the CU to request the UE context and cache the data packet until the UE context is established. To implement this operation, new signaling can be introduced in the interface between the CU (e.g., where the RRC entity is located) and the DU (e.g., where the MAC entity is located). Through the new message, the following signaling procedures can be supported between the CU and the DU. First, the DU sends a UE context acquisition request message to the CU to request the UE context. In this message, an I-RNTI or some other type of UE ID can be included to identify the UE. In addition to the ID, the data packet can also be included, or the data packet can be cached on the DU after the UE context is established and sent to the CU. Second, the DU receives a context establishment message to establish the UE context.

[0087] If the UE context does not exist on the DU, the DU can also forward the data packet to the CU through a common GTP tunnel or the F1 Application Protocol (F1AP). A common GTP tunnel means that the GTP tunnel is not UE-specific, but can be cell-specific or DU-specific. Once the DU forwards the data packet, the following information can be forwarded together: the I-RNTI or some other type of UE ID; and the logical channel ID of the data packet.

[0088] In the sixth embodiment, consideration is given to how to provide security protection for data transmission without state transition. In the current NR, whenever a UE enters the RRC_INACTIVE state, the NCC (Next-hop Chaining Count) is configured for the UE via the RRC Release message. The NCC will be used to generate a new key, which is used to receive the RRC Resume message. However, in order to avoid frequent key updates during data transmission, the old key can still be used for data transmission under RRC_INACTIVE until the RRC Resume process is triggered, as Figure 6 shown.

[0089] Figure 6 shows an exemplary method of data transmission using a security key in an energy-saving state according to an embodiment of the present disclosure. As Figure 6 shown, at operation 601, the BS 610 sends an RRC Release message with the NCC to the UE 620. After the UE 620 enters the RRC_INACTIVE state (or another energy-saving state) at operation 602, one or more data transmissions can be selectively performed between the BS 610 and the UE 620 based on the old key used by the UE 620 before entering the RRC_INACTIVE state at operation 603. At operation 604, the UE 620 determines to initiate a state transition. Then at operation 605, the UE 620 sends an RRC Resume Request to the BS 610 based on the old key. Both the BS 610 and the UE 620 can independently generate the same new key. At operation 606, the BS 610 sends an RRC Resume message to the UE 620 based on the new key. In this case, the UE uses the old key in operations 601 to 605 until the Resume process is initiated. Figure 6 The order of the operations shown can be changed according to different embodiments of the present disclosure. Specifically, there is no strict order between operations 604 and 605.

[0090] Therefore, for the data packet transmission in step 2, the security material used by the UE before entering the energy-saving state will be used for the security protection (i.e., integrity protection and / or encryption) of "data transmission in the energy-saving state without state transition". The security material can include: a security key (KeNB or KgNB) and / or a security algorithm.

[0091] The UE can continue to use the security key that was used before entering the energy-saving state (e.g., RRC_INACTIVE), and switch to a new security key after any of the following: receiving a DL DCCH message that triggers a state transition (e.g., RRC Resume); sending a UL CCCH or UL DCCH message that requests a state transition (e.g., RRC Resume Request); receiving a DL DCCH message; sending a UL CCCH message; an indicator carried in the PDCP header or RRC message. For the UL CCCH or UL DCCH message, the new security key can be used after the message is sent by the lower layer, after the lower layer (e.g., MAC or RLC) acknowledges the transmission, or after contention resolution is completed in the RA procedure during which the message is sent. For each of the above time points, a pre-configured (e.g., configurable via RRC signaling) or pre-defined (e.g., specified in the protocol) offset can be added.

[0092] For PDCP operations, the PDCP suspension operation can be performed each time the UE enters the RRC_INACTIVE state, and the PDCP COUNT value is reset. However, to support data transmission under RRC_INACTIVE, the PDCP COUNT value should remain the same during the RRC_INACTIVE state. To achieve this, the following alternative solutions can be considered. In the first alternative, an indicator can be added to the RRC message that pushes the UE into the RRC_INACTIVE state to indicate whether the PDCP count value should be reset. This indicator can be the same as the indicator that allows data transmission under RRC_INACTIVE, or it can be a separate indicator. In the second alternative, an indicator can be added to the system information to indicate whether the PDCP COUNT value should be reset. This indicator can be the same as the indicator used to allow data transmission under RRC_INACTIVE, or it can be a separate indicator. In one example, if the indicator is configured, the PDCP counter may not be reset during the PDCP suspension and / or resume process, or the PDCP entity may not be suspended. In another example, if data transmission under RRC_INACTIVE is allowed, the PDCP counter may not be reset during the PDCP suspension and / or resume process, or the PDCP entity may not be suspended. The above operations apply to all PDCP entities on the UE side, or only to the PDCP entity that belongs to the logical channel (or logical channel of the LCH) for which data transmission under the RRC_INACTIVE state is allowed.

[0093] In the seventh embodiment, when the payload of the RACH procedure is not sufficient to include all the data cached at the UE side, the following stateless transition data transmission can be considered. In one example, in addition to the one-shot RACH / grant-free transmission, the capacity provided by the "payload of Msg 1 in the two-step RACH" or "Msg 3 in the four-step RACH" or "grant-free transmission" is limited. Therefore, even if the data is very small, some data will remain in the cache. Considering the following possible DL transmissions (such as TCP acknowledgments (ACKs), RLC ACKs, etc.), it is advisable to allow the UE to briefly enter a "temporary time period" for continuous monitoring of the PDCCH.

[0094] In one example, the UE enters the "temporary time period" only when the RACH procedure is successfully completed or after transmission via grant-free resources. During the "temporary time period", the UE can monitor the PDCCH using the C-RNTI allocated during the RACH procedure or monitor the PDCCH using the I-RNTI. The monitoring of the PDCCH will be based on the configuration received in the system information (such as CORESET, search space, etc.).

[0095] The length of the "temporary time period" can be controlled by a temporary activity timer. The temporary activity timer can be restarted based on the received PDCCH. Once the timer expires, the UE will exit the "temporary time period", discard the C-RNTI, and enter a pure power-saving state (such as the RRC_INACTIVE or RRC_IDLE state). The detailed procedure is shown in Figure 7 shown below.

[0096] The temporary activity timer can be configured for the UE through the following alternatives. In alternative 1: The temporary activity timer can be included in the system information. If multiple PLMNs or multiple RAN notification areas are supported in a cell, the timer can be provided per PLMN or per RAN notification area. In alternative 2: The temporary activity timer can be configured through dedicated signaling. The dedicated signaling can be the dedicated signaling that pushes the UE into the energy-saving state, or the dedicated signaling received by the UE before entering the energy-saving state. The temporary activity timer can be configured per UE or per logical channel or per logical channel group or per DRB or per PDU session or per QoS flow. If the timer is configured per logical channel or logical channel group or per DRB or per PDU session or per QoS flow, the timer associated with the logical channel or logical channel group or provided per PDU session or per QoS flow (where there is data available for transmission) is used. If there is data available in multiple logical channels or logical channel groups, the timer with a larger or smaller value can be used. In alternative 3: The temporary activity timer can be configured during the RA procedure. If two-step RACH is used, the temporary activity timer can be carried in Msg2 through L2 signaling (such as a field in MAC CE, MAC sub-header, or random access response (RAR)) or L1 signaling (such as a field in DCI); if four-step RACH is used, the timer can be carried in Msg 2 or Msg4 through L2 signaling (such as a field in MAC CE, MAC sub-header, or RAR) or L1 signaling (such as a field in DCI).

[0097] If the temporary activity timer is not configured, after successfully completing the RACH procedure, the UE will not start such a timer and will stop monitoring the PDCCH based on the C-RNTI. That is, after successfully completing the RACH procedure, the UE will remain in the energy-saving state.

[0098] The temporary activity timer can be maintained in the MAC or RRC. If the temporary activity timer is maintained in the MAC, once the temporary activity timer expires, the NW will release the UE context in the MAC. For the start of the temporary activity timer, the following alternatives can be considered. In the first alternative, for two-step RACH, once the corresponding Msg 2 is received, or at a certain offset after the reception of the corresponding Msg 2, the temporary activity timer will be started. The offset can be configured by the NW or specified in the protocol. In the second alternative, for four-step RACH, once the corresponding Msg 4 is received, or at a certain offset after the reception of the corresponding Msg 4, the temporary activity timer will be started. The offset can be configured by the NW or specified in the protocol. The "corresponding Msg 2" or "corresponding Msg 4" means that the UE contention resolution ID or UE ID or I-RNTI is included in Msg 2 or Msg 4. Once the PDCCH is received through the corresponding UE ID, the temporary activity timer will be restarted. The UE ID can be C-RNTI or I-RNTI or some newly defined radio network temporary ID.

[0099] In the eighth embodiment, the configuration content mentioned in step 1 is considered. Based on the above description, the configuration mentioned in step 1 may include the parameters identified in the first, second, and / or seventh embodiments. For example, the configuration may include the configuration of RA resources. Separate configurations can be provided for normal RA and RA for data transmission in the INACTIVE state, including resources in terms of time domain, frequency domain, power domain (e.g., parameters related to power control), and / or code domain. The configuration may also include the configuration for grant-free transmission, including resources for grant-free transmission in terms of time domain, frequency domain, power domain (e.g., parameters related to power control), and / or code domain. The configuration may also include an indicator indicating whether data transmission in the energy-saving state is supported and / or allowed. The configuration may also include the configuration of the area range, which involves in which area data transmission in the energy-saving state is allowed. The configuration may also include the configuration for the selection between data transmission after state transition and data transmission in the energy-saving state without state transition. The configuration for this selection may include: for which logical channels and / or logical channel groups and / or DRBs and / or QoS flows and / or PDU sessions, data transmission in the energy-saving state without state transition is allowed; and the buffer size threshold to be used in the process selection.

[0100] Figure 7An exemplary method of data transmission using a two-step random access channel (RACH) procedure in an energy-saving state according to an embodiment of the present disclosure is shown. First, the UE 720 enters an energy-saving state (e.g., RRC_INACTIVE state or RRC_IDLE state), and receives and stores a configuration for "data transmission without state transition" from the BS 710, for example, at some time before operation 701. The configuration can be sent to the UE 720 via system information or dedicated RRC signaling. Then, at operation 701, the UE 720 in the energy-saving state determines to initiate "data transmission without state transition" based on this configuration.

[0101] At operation 702, the UE 720 initiates a two-step RACH procedure. In the two-step RACH procedure, the UE 720 includes an I-RNTI, an uplink data packet, and / or a buffer status report (BSR) in the payload part of Msg 1. Then, at operation 703, the UE 720 receives the corresponding Msg 2 from the BS 710. After receiving the corresponding Msg 2, the UE 720 starts a temporary activity timer (if it is configured) and monitors the PDCCH based on the C-RNTI (or I-RNTI or some newly defined radio network temporary ID) until the timer expires. Meanwhile, one or more data transmissions can optionally be performed at operation 704 based on scheduling. When the timer is running, the UE 720 is in a temporary time period. If the temporary activity timer is not configured, the UE 720 will stop monitoring the PDCCH based on the C-RNTI (or I-RNTI or some newly defined radio network temporary ID) and end the procedure.

[0102] Once the timer expires, the UE 720 discards the C-RNTI or the newly defined radio network temporary ID received in Msg 2 at operation 705 and stops monitoring the PDCCH via the C-RNTI. The BS 710 also monitors the timer. Once the timer expires, the BS710 determines at operation 705 that the UE 720 exits the temporary time period and returns to the pure energy-saving state. If the UE 720 has more data (or newly arrived data) to send after operation 705 and the UE 720 determines to continue "data transmission without state transition", operations 702 to 705 can be repeated. Figure 7 The order of some of the operations shown can be changed according to different embodiments of the present disclosure.

[0103] Figure 8 An exemplary method of data transmission using a four-step RACH procedure in an energy-saving state according to an embodiment of the present disclosure is shown.

[0104] First, the UE 820 enters an energy-saving state (e.g., the RRC_INACTIVE state or the RRC_IDLE state) and receives and stores the configuration for "stateless transition data transmission" from the BS 810, e.g., at some time before operation 801. The configuration can be sent to the UE 820 via system information or dedicated RRC signaling. Then, at operation 801, the UE 820 in the energy-saving state determines to initiate "stateless transition data transmission" based on this configuration.

[0105] At operation 802, the UE 820 initiates a four-step RACH procedure and sends a preamble to the BS 810 via Msg 1. Then, at step 803, the UE 820 receives the corresponding Msg 2 from the BS 810. During the four-step RACH procedure, the UE 820 includes the I-RNTI, uplink data packet, and / or buffer status report (BSR) in the payload part of Msg 3, and Msg 3 is sent to the BS 810 at operation 804. At operation 805, the UE 820 receives the corresponding Msg 4 from the BS 810. After receiving the corresponding Msg4, the UE 820 starts a temporary activity timer (if it is configured) and monitors the PDCCH based on the C-RNTI (or I-RNTI or some newly defined radio network temporary ID) until the timer expires. Meanwhile, one or more data transmissions can optionally be performed at operation 806 based on scheduling. When the timer is running, the UE 820 is in a temporary time period. If the temporary activity timer is not configured, the UE 820 stops monitoring the PDCCH based on the C-RNTI (or I-RNTI or some newly defined radio network temporary ID) and ends the procedure.

[0106] Once the timer expires, the UE 820 discards the C-RNTI or the newly defined radio network temporary ID received in Msg 2 at operation 807 and stops monitoring the PDCCH via the C-RNTI. The BS 810 also monitors the timer. Once the timer expires, the BS810 determines at operation 807 that the UE 820 exits the temporary time period and returns to the pure energy-saving state. If the UE 820 has more data (or newly arrived data) to send after operation 807 and the UE 820 determines to continue "stateless transition data transmission", operations 802 to 807 can be repeated. Figure 8 The order of some of the operations shown can be changed according to different embodiments of the present disclosure.

[0107] Although various embodiments of the present disclosure have been described above, it should be understood that they are presented by way of example and not limitation. Similarly, various diagrams may depict example architectures or configurations, and providing these example architectures or configurations enables those of ordinary skill in the art to understand the exemplary features and functions of the present disclosure. However, those skilled in the art will understand that the present disclosure is not limited to the example architectures or configurations shown, but rather can be implemented using a variety of alternative architectures and configurations. Additionally, those of ordinary skill in the art will understand that one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Accordingly, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

[0108] It should also be understood that any reference to elements using designations such as "first," "second," etc. herein generally does not limit the number or order of these elements. Rather, these designations are used herein as a convenient means of distinguishing between two or more elements or between multiple instances of one element. Thus, the reference to a first and a second element does not mean that only two elements can be employed, nor does it mean that the first element must be located before the second element in some manner.

[0109] Furthermore, those of ordinary skill in the art will understand that any of a variety of different technologies can be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, and symbols, as referred to in the above description, can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0110] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, devices, circuits, methods, and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of both), firmware, various forms of program or design code containing instructions (referred to herein for convenience as "software" or "software modules"), or any combination of these technologies.

[0111] To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above in terms of functionality. Implementing such functionality as hardware, firmware, or software, or a combination of these techniques, depends on the particular application and the design constraints imposed on the overall system. A person skilled in the art can implement the described functionality in various ways for each particular application, but such implementation decisions do not result in departing from the scope of the present disclosure. According to various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. As used herein with respect to a particular operation or function, the term "configured to" or "configured for" refers to a processor, device, component, circuit, structure, machine, module, etc. that is physically constructed, programmed, and / or arranged to perform the specified operation or function.

[0112] In addition, those of ordinary skill in the art will understand that the various exemplary logical blocks, modules, devices, components, and circuits described herein can be implemented within or performed by an integrated circuit (IC) including a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include antennas and / or transceivers to communicate with various components within a network or within a device. A general-purpose processor can be a microprocessor, but alternatively, the processor can be any conventional processor, controller, or state machine. The processor can 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 in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[0113] If implemented in software, the functionality can be stored as one or more instructions or code on a computer-readable medium. Accordingly, the steps of the methods or algorithms disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, and communication media include any medium that can enable a computer program or code to be transferred from one place to another. Storage media can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0114] As used herein, the term "module" refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purposes of discussion, various modules are described as discrete modules. However, it will be apparent to one of ordinary skill in the art that two or more modules may be combined to form a single module that performs the associated functions in accordance with embodiments of the present disclosure.

[0115] Additionally, in embodiments of the present disclosure, a memory or other storage device and communication components may be employed. It should be understood that, for clarity, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable functional distribution between different functional units, processing logic elements, or domains may be used without departing from the present disclosure. For example, functions illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Thus, the reference to a particular functional unit is only a reference to a suitable means for providing the described functionality, rather than indicating a strict logical or physical structure or organization.

[0116] Various modifications to the implementations described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of the disclosure. Therefore, this disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein as set forth in the following claims.

Claims

1. A method performed by a wireless communication device, the method comprising: Entering an energy saving state; While in the energy saving state, sending uplink data to a wireless communication node, Determining whether to remain in the energy saving state while sending the uplink data based on: The uplink data is related to a bitmap of a logical channel for which data transmission in the energy saving state allowing or not allowing stateless transition is permitted; And Receiving, from the wireless communication node, configuration information related to the energy saving state through at least one of system information and dedicated radio resource control (RRC) signaling, wherein the configuration information includes a bitmap for the logical channel, and the bitmap is used to indicate which logical channels are allowed or not allowed to support stateless transition data transmission.

2. The method according to claim 1, wherein the energy saving state is at least one of the following: Inactive state; Idle state; A state in which the wireless communication device does not maintain uplink synchronization; and A state in which the wireless communication device does not monitor a physical downlink control channel (PDCCH) based on a cell radio network temporary identifier (C-RNTI).

3. The method according to claim 1, wherein the configuration information further includes information related to at least one of the following: Configuration for random access resources; Configuration for grant-free transmission; An indicator indicating whether data transmission in the energy saving state is supported and / or permitted; Configuration for a regional scope including multiple cells, regarding whether data transmission in the energy saving state is supported and / or permitted in each of the multiple cells; and Configuration related to a selection between data transmission after state transition and data transmission in the energy saving state with stateless transition.

4. The method according to claim 1, further comprising determining data transmission in the energy saving state allowing stateless transition based on at least one of the following: A first indicator in system information, which indicates whether data transmission in the energy saving state allowing stateless transition is permitted in a cell; A second indicator in dedicated signaling, which indicates a cell list of at least one cell including data transmission in the energy saving state allowing stateless transition; A third indicator, which indicates whether data transmission in the energy saving state allowing stateless transition is permitted in a public land mobile network; A fourth indicator, which indicates whether data transmission in the energy saving state allowing stateless transition is permitted in a tracking area; A fifth indicator, which indicates whether data transmission in the energy saving state allowing stateless transition is permitted in a radio access network (RAN) notification area; Or Multiple indicators, each indicator corresponding to one of multiple cells in a regional scope, wherein each of the multiple indicators indicates whether data transmission in the energy saving state is permitted in the corresponding cell.

5. The method according to claim 1, further comprising determining data transmission in the energy saving state allowing stateless transition based on at least one of the following: A separate indicator related to the energy saving state; and A common indicator related to multiple energy saving states including the energy saving state.

6. The method according to claim 1, wherein the uplink data is transmitted based on at least one of the following: Grant-free transmission; and The payload of the random access procedure of the wireless communication node.

7. The method according to claim 6, wherein the payload refers to at least one of the following: The payload transmitted after the preamble in the first step of a two-step random access channel (RACH) procedure; The media access control (MAC) protocol data unit (PDU) transmitted in a message in the third step of a four-step RACH procedure; The payload transmitted after the preamble in a procedure similar to RACH; And The payload transmitted together with the demodulation reference signal (DMRS).

8. The method according to claim 6, wherein the payload includes information related to at least one of the following: The identity (ID) of the wireless communication device; At least one data packet of the uplink data; Buffer status report (BSR); Power headroom report (PHR); A flag indicating the reason for the random access procedure; A flag indicating whether the random access procedure is initiated for data transmission without a state transition; Radio resource control (RRC) message; and The data packet included in the RRC message.

9. The method according to claim 1, wherein the uplink data is included in at least one of the following: Media access control (MAC) service data unit (SDU) for which a MAC sub-header is allocated to indicate the logical channel to which the uplink data belongs; and At least one radio resource control (RRC) message, which is used as at least one of: bit string, octet string, and container.

10. The method according to claim 1, wherein: The uplink data is transmitted based on a security protection key of the uplink data; and The key is used by the wireless communication device before entering the energy-saving state.

11. The method according to claim 1, wherein: The uplink data is transmitted based on a first security protection key of the uplink data in response to at least one of the following: Receiving a downlink (DL) dedicated control channel (DCCH) message triggering a state transition, Transmitting an uplink (UL) common control channel (CCCH) message requesting a state transition, Transmitting a UL DCCH message requesting a state transition, Receiving any DL DCCH message, Transmitting any UL CCCH message, An indicator in the packet data convergence protocol (PDCP) header indicating the use of the first key, and An indicator in the radio resource control (RRC) message indicating the use of the first key; And The first key is different from a second key used by the wireless communication device before entering the energy-saving state.

12. The method according to claim 1, further comprising maintaining a packet data convergence protocol (PDCP) count value during the energy-saving state based on at least one of the following: A first indicator in the system information indicating whether the PDCP count value should be reset; and A second indicator in a dedicated RRC message indicating whether the PDCP count value should be reset.

13. The method according to claim 1 further comprises at least one of the following: determining additional data to be transmitted at the radio resource control (RRC) layer during the energy-saving state; and entering a time period during which the wireless communication device monitors a physical downlink control channel (PDCCH) via an identifier (ID) of the wireless communication device, with no state transition at the RRC layer.

14. The method according to claim 13 further comprises controlling a length of the time period based on a timer, wherein the timer is configured based on at least one of the following: system information; dedicated RRC signaling; a message or signaling in a second step of a two-step random access channel (RACH) procedure; a message or signaling in a second step of a four-step RACH procedure; and a message or signaling in a fourth step of a four-step RACH procedure.

15. The method according to claim 14, wherein controlling the length of the time period based on the timer comprises at least one of the following: starting the timer in response to at least one of the following: first receiving the message in the second step of the two-step RACH procedure, second receiving the message in the fourth step of the four-step RACH procedure, a first offset after the first reception in the second step of the two-step RACH procedure, and a second offset after the second reception in the fourth step of the four-step RACH procedure; restarting the timer when the PDCCH is received via the ID of the wireless communication device; and exiting the time period in response to the timer expiring.

16. A method performed by a wireless communication node, the method comprising: receiving uplink data from a wireless communication device while the wireless communication device is in an energy-saving state, determining, based on the following, whether to keep the wireless communication device in the energy-saving state during transmission of the uplink data: the uplink data is related to a bitmap of a logical channel for data transmission in the energy-saving state that allows or does not allow a state transition without status; and sending configuration information related to the energy-saving state to the wireless communication device via at least one of system information and dedicated radio resource control (RRC) signaling, wherein the configuration information includes a bitmap for the logical channel, and the bitmap is used to indicate which logical channels are allowed or not allowed to support data transmission without a state transition.

17. The method according to claim 16, wherein the energy-saving state is at least one of the following: an inactive state; an idle state; a state in which the wireless communication device does not maintain uplink synchronization; and a state in which the wireless communication device does not monitor a physical downlink control channel (PDCCH) based on a cell radio network temporary identifier (C-RNTI).

18. The method according to claim 16, wherein the configuration information further includes information related to at least one of the following: a configuration for random access resources; a configuration for grant-free transmission; an indicator indicating whether data transmission in the energy-saving state is supported and / or allowed. Configuration regarding whether data transmission in the energy-saving state is supported and / or permitted in each of the multiple cells for a regional scope including the multiple cells; and Configuration related to the selection between data transmission after a state transition and data transmission in the energy-saving state without a state transition.

19. The method according to claim 16, further comprising configuring to permit data transmission in the energy-saving state without a state transition based on at least one of the following: A first indicator in system information indicating whether data transmission in the energy-saving state without a state transition is permitted in a cell; A second indicator in dedicated signaling indicating a cell list of at least one cell including data transmission in the energy-saving state without a state transition; A third indicator indicating whether data transmission in the energy-saving state without a state transition is permitted in a public land mobile network; A fourth indicator indicating whether data transmission in the energy-saving state without a state transition is permitted in a tracking area; A fifth indicator indicating whether data transmission in the energy-saving state without a state transition is permitted in a radio access network (RAN) notification area; Multiple indicators, each indicator corresponding to one of the multiple cells in a regional scope, wherein each of the multiple indicators indicates whether data transmission in the energy-saving state is permitted in the corresponding cell; A separate indicator related to the energy-saving state; And A common indicator related to multiple energy-saving states including the energy-saving state.

20. The method according to claim 16, wherein the uplink data is received based on at least one of the following: Grant-free transmission; and The payload of a random access procedure of the wireless communication node.

21. The method according to claim 20, wherein the payload refers to at least one of the following: The payload transmitted after a preamble in the first step of a two-step random access channel (RACH) procedure; The media access control (MAC) protocol data unit (PDU) transmitted in a message in the third step of a four-step RACH procedure; The payload transmitted after a preamble in a procedure similar to RACH; And The payload transmitted together with a demodulation reference signal (DMRS).

22. The method according to claim 20, wherein the payload includes information related to at least one of the following: The identity (ID) of the wireless communication device; At least one data packet of the uplink data; A buffer status report (BSR); A power headroom report (PHR); A flag indicating the reason for the random access procedure; A flag indicating whether the random access procedure is initiated for data transmission without a state transition; A radio resource control (RRC) message; and The data packet included in the RRC message.

23. The method according to claim 20, wherein the uplink data is included in at least one of the following: A media access control (MAC) service data unit (SDU) for which a MAC sub-header is allocated to indicate the logical channel to which the uplink data belongs; and At least one Radio Resource Control (RRC) message, which is used as at least one of the following: bit string, octet string, and container.

24. The method according to claim 16, further comprising: Determining that there is no context of the wireless communication device in the Medium Access Control (MAC) layer of the wireless communication node; And Performing at least one of the following operations on the uplink data: Buffering the uplink data and sending an indication to a higher layer, Buffering the uplink data and sending an indication to the wireless communication device, Discarding the uplink data, and Forwarding the uplink data to a different node having the context of the wireless communication device.

25. The method according to claim 16, further comprising: Determining that there is no context of the wireless communication device in the Medium Access Control (MAC) layer of the distributed unit (DU) serving as a central unit (CU) of the wireless communication node; And Performing at least one of the following operations on the uplink data: Sending a message to the CU to request the context of the wireless communication device and buffering the uplink data until the context is established, and Forwarding the uplink data to the CU through a common tunnel not specific to the wireless communication device.

26. The method according to claim 16, wherein: Receiving the uplink data based on a security protection key of the uplink data; and The key is used by the wireless communication device before entering the energy saving state.

27. The method according to claim 16, wherein: Receiving the uplink data based on a first security protection key of the uplink data in response to at least one of the following: A Downlink (DL) Dedicated Control Channel (DCCH) message triggering a state transition, An Uplink (UL) Common Control Channel (CCCH) message requesting a state transition, A UL DCCH message requesting a state transition, Any DL DCCH message, Any UL CCCH message, An indicator in a Packet Data Convergence Protocol (PDCP) header indicating the use of the first key, and An indicator in a Radio Resource Control (RRC) message indicating the use of the first key; And The first key is different from a second key used by the wireless communication device before entering the energy saving state.

28. The method according to claim 16, further comprising indicating to the wireless communication device to maintain a Packet Data Convergence Protocol (PDCP) count value during the energy saving state based on at least one of the following: A first indicator in system information indicating whether the PDCP count value should be reset; and A second indicator in a dedicated RRC message indicating whether the PDCP count value should be reset.

29. The method according to claim 16, further comprising: Receiving additional data from the wireless communication device while the wireless communication device is in a time period: within the time period, the wireless communication device monitors a Physical Downlink Control Channel (PDCCH) through an identifier (ID) of the wireless communication device without a state transition in the Radio Resource Control (RRC) layer.

30. The method according to claim 29, further comprising controlling a length of the time period based on a timer, wherein the timer is configured based on at least one of the following: system information; dedicated RRC signaling; a message or signaling in a second step of a two-step random access channel (RACH) procedure; a message or signaling in a second step of a four-step RACH procedure; and a message or signaling in a fourth step of a four-step RACH procedure.

31. The method according to claim 30, wherein: the timer is started in response to at least one of the following: the wireless communication device receives the message for the first time in the second step of the two-step RACH procedure, the wireless communication device receives the message for the second time in the fourth step of the four-step RACH procedure, a first offset after the first reception in the second step of the two-step RACH procedure, and a second offset after the second reception in the fourth step of the four-step RACH procedure; the timer is restarted when the wireless communication device receives the PDCCH via the ID of the wireless communication device; and the wireless communication device exits the time period in response to the timer expiring.

32. A wireless communication device, comprising a processor and a memory, the processor being configured to read instructions from the memory to perform the method according to any one of claims 1 to 15.

33. A wireless communication node, comprising a processor and a memory, the processor being configured to read instructions from the memory to perform the method according to any one of claims 16 to 31.

34. A non-transitory computer-readable medium, having stored thereon computer-executable instructions for performing the method according to any one of claims 1 to 31.

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