User equipment and network entities and the methods they perform for wireless communication

Abstract

This disclosure provides systems, methods, and apparatus for wireless communication, including computer programs encoded on a computer storage medium. In one aspect of this disclosure, a user equipment (UE) is configured to manage state variables (associated with a Radio Link Control (RLC) entity or a Packet Data Convergence Protocol (PDCP) entity) that enable the UE to maintain synchronization with a base station during a communication session. For example, the base station may send a control PDU or synchronization PDU to the UE, including values ​​of state variables maintained by the base station, to enable the UE to update its state variables to maintain synchronization with the base station. Other aspects and features are also claimed and described.

Description

[0001] Cross-references to related applications

[0002] This application claims the rights of U.S. Patent Application No. 17 / 451,618, filed October 20, 2021, entitled “MANAGEMENT OF ONE OR MORE STATEVARIABLES ASSOCIATED WITH A COMMUNICATION WINDOW”; U.S. Provisional Patent Application No. 63 / 094,862 (2100384P1), filed October 21, 2020, entitled “MANAGEMENT OF ONE OR MORE RADIO LINKCONTROL (RLC) STATE VARIABLES”; and U.S. Provisional Patent Application No. 63 / 109,784 (2100384P2), filed November 4, 2020, entitled “MANAGEMENT OF ONE OR MORE STATE VARIABLES ASSOCIATED WITH A COMMUNICATION WINDOW”, the disclosure of each of which is incorporated herein by reference in its entirety, as if fully set forth herein and used for all applicable purposes. Technical Field

[0003] The aspects of this disclosure generally relate to wireless communication systems, and more specifically to the management of one or more state variables associated with a communication window, such as the management of one or more Radio Link Control (RLC) state variables or the management of one or more Packet Data Convergence Protocol (PDCP) state variables. Background Technology

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. Wireless multiple access communication systems can include multiple base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be referred to as User Equipment (UE). These systems may be able to support communication with multiple UEs by sharing available system resources, such as time, frequency, and power. Examples of such multiple access systems include fourth-generation (4G) systems, such as Long Term Evolution (LTE) systems, LTE-A Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth-generation (5G) systems, which are referred to as New Radio (NR) systems. These systems can employ technologies such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform-Extended-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM).

[0005] A UE can engage in unicast or point-to-point (P2P) communication sessions with a base station. To participate in a communication session, the UE configures the radio bearer using a Radio Link Control (RLC) entity, and the RLC entity initializes the state variables for the RLC Acknowledgment Mode (AM) window management function. During a communication session, the UE, specifically the RLC entity, can update the state variables to enable communication. In unicast communication, the sending and receiving RLC windows are synchronized via an RLC sliding window movement process without any explicit adjustment commands from the sending RLC entity to the receiving RLC entity. If the UE attempts a radio link failure recovery procedure or reconfigures the radio bearer during a handover procedure, the UE re-establishes the RLC entity and reinitializes the state variables to their initial values ​​to resume the unicast or point-to-point communication session.

[0006] UEs can also participate in point-to-multipoint (P2M) communication sessions, such as those for streaming movies or sports games, other entertainment, or mission-critical information. In a P2M communication session, the UE can operate in RLC Acknowledgment Mode (AM), where the base station uses a single RLC AM transmitter to send content to the UE RLC AM receivers of multiple corresponding UEs. During a P2M communication session, the values ​​of the state variables of the UE RLC AM window management function, which maintains the communication window for the UE's P2M communication session, can become out of sync with the base station. As a result of this asynchrony between the UE and base station's state variables, the UE may discard one or more received packets for the communication session because they are outside the communication window maintained by the UE. For example, the UE may have just performed a handover operation, the RLC communication window may be paused, or the UE may join an ongoing multicast session. Because the base station uses a single RLC AM transmitter to send content associated with the communication session to multiple UEs, it cannot adjust the RLC transmission window to maintain synchronization on a per-UE basis. Therefore, when these RLC packets fall outside the UE's RLC reception window, the UE RLC reception window becoming out of sync with the base station's transmission RLC window may cause the UE to be unable to receive RLC packets from the base station.

[0007] Furthermore, when configuring a multicast bearer (MRB) for a communication session, a stack comprising multiple layers can be established, such as one or more of the Serving Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, RLC layer, Media Access Control (MAC) layer, or Physical (PHY) layer. For example, to participate in a communication session, the UE configures a PDCP entity, and the PDCP entity initializes the state variables of the PDCP window management function. During a communication session, the values ​​of the state variables of the UE PDCP window management function, which maintains the communication window of the UE's P2M communication session, can become out of sync with the base station. As a result of this asynchrony between the UE and the base station's state variables, the UE can discard one or more received packets from the communication session because they are outside the PDCP communication window maintained by the UE based on the state variables. For example, if the UE joins an existing multicast session, the UE can set one or more state variables associated with the PDU communication window to initial values ​​that may not match or be out of sync with the values ​​of the state variables of the base station's PDCP entity. Therefore, the UE state variables used to maintain the UE PDCP communication window become out of sync with the base station state variables used to maintain the base station PDCP communication window. When these PDCP PDUs fall outside the UE's PDCP communication window, it may cause the UE to be unable to receive PDCP PDUs from the base station. Summary of the Invention

[0008] The following summarizes some aspects of this disclosure to provide a basic understanding of the techniques discussed. This overview is not a comprehensive summary of all intended features of this disclosure, and its purpose is neither to identify key or essential elements of all aspects of this disclosure, nor to describe the scope of any or all aspects of this disclosure. Its sole purpose is to present some concepts of one or more aspects of this disclosure in an overview form as a prelude to the more detailed description that follows.

[0009] An innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication performed by a user equipment (UE). The method includes initializing a set of state variables to a first set of initial values. This set of state variables is associated with the synchronization of a communication window of a communication session. The method also includes receiving a control message including an indication of a second set of current values ​​associated with corresponding state variables in the set of state variables. At least one of the current values ​​differs from the corresponding initial value. The method further includes setting the set of state variables to the second set of current values ​​to synchronize the communication window with the communication session, and receiving or transmitting packets associated with the communication session within the synchronized communication window.

[0010] Another innovative aspect of the subject matter described in this disclosure can be implemented in a UE. The UE includes at least one processor and a memory coupled to the at least one processor and storing processor-readable instructions configured, when executed by the at least one processor, to initialize a set of state variables to a first set of initial values. This set of state variables is associated with the synchronization of a communication window of a communication session. When executed by the at least one processor, the processor-readable instructions are also configured to receive a control message including an indication of a second set of current values ​​associated with a corresponding state variable in the set of state variables. At least one current value differs from the corresponding initial value. When executed by the at least one processor, the processor-readable instructions are also configured to set the set of state variables to the second set of current values ​​to synchronize the communication window with the communication session, and to receive or transmit packets associated with the communication session within the synchronized communication window.

[0011] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus configured for wireless communication. The apparatus includes components for initializing a set of state variables to a first set of initial values. This set of state variables is associated with the synchronization of a communication window of a communication session. The apparatus also includes components for receiving a control message including an indication of a second set of current values ​​associated with corresponding state variables in the set of state variables. At least one current value differs from the corresponding initial value. The apparatus further includes components for setting the set of state variables to the second set of current values ​​to synchronize the communication window with the communication session, and components for receiving or transmitting packets associated with the communication session within the synchronized communication window.

[0012] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations including initializing a set of state variables to a first set of initial values. This set of state variables is associated with the synchronization of a communication window of a communication session. The operations also include receiving a control message including an indication of a second set of current values ​​associated with corresponding state variables in the set of state variables. At least one current value differs from the corresponding initial value. The operations further include setting the set of state variables to the second set of current values ​​to synchronize the communication window with the communication session, and receiving or transmitting packets associated with the communication session within the synchronized communication window.

[0013] Another innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication performed by a base station. The method includes generating a control message that includes an indication of a set of values ​​for a set of state variables associated with a communication window of a communication session. This set of values ​​synchronizes the communication window and differs from an initial set of values ​​for the set of state variables. The method also includes sending the control message to a UE.

[0014] Another innovative aspect of the subject matter described in this disclosure can be implemented in a base station. The base station includes at least one processor and a memory coupled to the at least one processor and storing processor-readable code configured, when executed by the at least one processor, to generate a control message including indications of a set of values ​​for a set of state variables associated with a communication window of a communication session. This set of values ​​synchronizes the communication window and differs from an initial set of values ​​for the set of state variables. When executed by the at least one processor, the processor-readable code is also configured to initiate the transmission of a control message to the UE.

[0015] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus configured for wireless communication. The apparatus includes components for generating control messages that include indications of a set of values ​​for a set of state variables associated with a communication window of a communication session. These values ​​synchronize the communication window and differ from an initial set of values ​​for the set of state variables. The apparatus also includes components for transmitting control messages to a UE.

[0016] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations including generating a control message that includes indications of a set of values ​​for a set of state variables associated with a communication window of a communication session. This set of values ​​synchronizes the communication window and differs from an initial set of values ​​for the set of state variables. The operation also includes initiating the transmission of a control message to the UE.

[0017] Other aspects, features, and implementations of this disclosure will become apparent to those skilled in the art from the following description of specific, exemplary implementations of this disclosure, taken in conjunction with the accompanying drawings. While features of this disclosure may be described with respect to the specific implementations and illustrations below, all implementations of this disclosure may include one or more advantageous features described herein. In other words, when one or more implementations can be described as having specific advantageous features, one or more such features may also be used according to various implementations of this disclosure described herein. Similarly, while exemplary implementations may be described below as implementations of devices, systems, or methods, such exemplary implementations may be implemented in various devices, systems, and methods. Attached Figure Description

[0018] A further understanding of the nature and advantages of this disclosure can be achieved by referring to the following accompanying drawings. In the drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by adding a second reference numeral after the reference numeral or by using a dash and a second reference numeral to distinguish similar components. If only the first reference numeral is used in the specification, the description applies to any similar components having the same first reference numeral, regardless of the second reference numeral.

[0019] Figure 1 It is a block diagram illustrating the details of an example wireless communication system based on one or more aspects.

[0020] Figure 2 It is a block diagram illustrating examples of base stations and user equipment (UE) from one or more aspects.

[0021] Figure 3 This is a block diagram illustrating an example wireless communication system that supports the management of state variables, based on one or more aspects.

[0022] Figure 4 This is a block diagram of another example wireless communication system that supports the management of state variables, based on one or more aspects.

[0023] Figure 5 It is a flowchart illustrating an example process that supports the management of state variables from one or more aspects.

[0024] Figure 6 This is a block diagram of an example UE that supports the management of state variables based on one or more aspects.

[0025] Figure 7 It is a flowchart illustrating an example process that supports the management of state variables from one or more aspects.

[0026] Figure 8 This is a block diagram of an example base station that supports the management of state variables based on one or more aspects.

[0027] Similar reference numerals and names in different figures indicate similar elements. Detailed Implementation

[0028] The various aspects of this disclosure are described more fully below with reference to the accompanying drawings. However, this disclosure may be implemented in many different forms and should not be construed as limited to any particular structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those skilled in the art. Based on the teachings herein, those skilled in the art will understand that the scope of this disclosure is intended to cover any aspect disclosed herein, whether implemented independently of or in combination with any other aspect of this disclosure. For example, an apparatus may be implemented using any number of the aspects set forth herein, or a method may be practiced. Additionally, the scope of this disclosure is intended to cover such apparatuses or methods practiced using other structures, functions, or structures and functions other than or attached to the various aspects of this disclosure described herein. Any aspect of this disclosure disclosed herein may be embodied by one or more elements of the claims.

[0029] Various aspects of this disclosure relate to techniques that enable a user equipment (UE) to keep one or more state variables of the UE synchronized with one or more corresponding state variables of a network entity (such as a base station) during a communication session. The UE can use state variables to keep a communication window synchronized with a corresponding communication window maintained by the network entity, based on the corresponding state variables of the network entity. For example, the state variables can be associated with the UE's Radio Link Control (RLC) Entity Acknowledged Mode (AM) window function, the UE's RLC Entity Unacknowledged Mode (UM) window function, or the Packet Data Convergence Protocol (PDCP) Entity window function. In various examples, communication can be a unicast communication session, a multicast communication session, or a broadcast communication session with a base station. In some aspects, the UE can establish an entity, such as an RLC entity or a PDCP entity, to join the communication session and can initialize a set of state variables associated with a communication window, such as a sliding window. For example, a set of state variables can be initialized to a set of initial values. After the UE successfully configures the entity, the base station can send a control message (such as a Control Protocol Data Unit (PDU)) to the UE, which includes a set of current values ​​of the corresponding state variables maintained by the base station, enabling the UE to update its state variables based on that set of current values. For example, a UE can update its state variables to match the current values ​​in that set. By updating its state variables based on the current values ​​in that set, the UE can synchronize the communication window of its communication session with the base station. In some implementations, control PDUs can be sent without an assigned RLC sequence number (SN).

[0030] In some aspects, during a communication session, the UE can perform a handover operation from the current cell associated with a base station to a target cell associated with the base station or a different base station, and can re-establish an entity as part of the handover operation. Based on the successful completion of the handover operation, the base station associated with the target cell can send a control PDU (without an assigned RLC SN) to the UE, enabling the UE to update its state variables and maintain synchronization between the UE and the base station associated with the target cell.

[0031] In some aspects, the base station may send one or more synchronization PDUs to the UE during a communication session. For example, the base station may send synchronization PDUs periodically. In some examples, each synchronization PDU may include an RLC SN or be sent along with an RLC SN, and may include one or more current values ​​of one or more state variables maintained by the base station, enabling the UE to determine whether to update its corresponding state variables to synchronize the communication window of the communication session with the base station. Furthermore, if the UE does not receive packets associated with an entity within a communication window for a period of time, the UE may determine that the communication window is "stagnant," and the UE may subsequently re-establish the entity, which in turn may lead to an interruption of the communication session for the UE.

[0032] Specific implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. By providing the UE with control messages that include the current values ​​of state variables maintained by the base station, the UE can update its state variables to manage its communication window, thereby maintaining synchronization with the base station and experiencing fewer interruptions during a communication session, thus improving the user experience. In some implementations, control can be sent without an assigned RLC SN, which can reduce communication overhead. Furthermore, in implementations where the base station sends one or more synchronization PDUs, the one or more synchronization PDUs enable the UE to maintain synchronization with the base station's communication window and prevent the communication window from becoming stagnant.

[0033] In various implementations, the techniques, processes, and apparatus disclosed herein can be used in wireless communication networks such as Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single Carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, fifth-generation (5G) or new radio (NR) networks (sometimes referred to as "5GNR" networks, systems, or devices), and other communication networks. As described herein, the terms "network" and "system" are used interchangeably.

[0034] CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. UTRA includes Wideband CDMA (W-CDMA) and Low Chip Rate (LCR). CDMA2000 covers the IS-2000, IS-95, and IS-856 standards.

[0035] TDMA networks can implement radio technologies such as the Global System for Mobile Communications (GSM). 3GPP defines the standard for the GSM EDGE (Enhanced Data Rate for GSM Evolution) Radio Access Network (RAN) (also known as GERAN). GERAN is the radio component of GSM or GSM EDGE, and the network connecting base stations (e.g., Ater and Abis interfaces) and base station controllers (e.g., A interface). The radio access network represents a component of the GSM network that routes telephone calls and packet data from the Public Switched Telephone Network (PSTN) and the Internet to the subscriber's handheld device (also known as the user terminal or user equipment (UE)) and from the handheld device to the network. A mobile phone operator's network may include one or more GERANs; in the case of UMTS or GSM networks, the GERAN may be coupled to the UTRAN. Furthermore, an operator's network may include one or more LTE networks, or one or more other networks. Various network types can use different radio access technologies (RATs) and radio access networks (RANs).

[0036] OFDMA networks can implement radio technologies such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, and flash-OFDM. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a UMTS version using E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization called the 3rd Generation Partnership Project (3GPP), while CDMA2000 is described in documents provided by an organization called the 3rd Generation Partnership Project 2 (3GPP2). These different radio technologies and standards are either known or under development. For example, 3GPP is a collaboration between telecommunications associations aimed at defining globally applicable third-generation (3G) handset specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the Universal Mobile Telecommunications System (UMTS) mobile phone standard. 3GPP can define specifications for next-generation mobile networks, mobile systems, and mobile devices. This disclosure may describe certain aspects with reference to LTE, 4G, 5G, or NR technologies; however, this description is not intended to be limited to any particular technology or application, and one or more aspects described with reference to one technology may be understood to be applicable to another technology. In fact, one or more aspects of this disclosure relate to shared access to radio spectrum between networks using different radio access technologies or radio air interfaces.

[0037] 5G networks consider using a unified, OFDM-based air interface to enable different deployments, different spectrums, and different services and devices. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to extend to provide coverage for: (1) areas with ultra-high density (e.g., ~ per km) 2 (1) Large-scale Internet of Things (IoT) with 1M nodes, ultra-low complexity (e.g., ~10s bits per second), ultra-low energy (e.g., ~10+ years of battery life), and deep coverage and ability to reach challenging locations; (2) Mission-critical controls with robust security to protect sensitive personal, financial, or confidential information, ultra-high reliability (e.g., ~99.9999% reliability), ultra-low latency (e.g., ~1 millisecond (ms)), and users with wide mobility or lack of mobility; and (3) Extremely high capacity (e.g., ~1M nodes per kilometer). 2 10 Tbps), extremely high data rates (such as multi-Gbps rates, 100+ Mbps user experience rates), and enhanced mobile broadband with a deep understanding of advanced discovery and optimization.

[0038] Devices, networks, and systems can be configured to communicate via one or more portions of the electromagnetic spectrum. The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc., based on or wavelength. In 5G NR, two initial operating frequency bands were identified as the frequency range designations FR1 (410 MHz – 7.125 GHz) and FR2 (24.25 GHz – 52.6 GHz). The frequencies between FR1 and FR2 are generally referred to as intermediate frequencies (IFs). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as the “sub-6 GHz” band in various documents and articles. Similar naming issues sometimes arise with FR2, which is often referred to (interchangeably) as the “millimeter wave” (mmWave) band in documents and articles, although this differs from the extremely high frequency (EHF) band (30 GHz – 300 GHz) defined as a millimeter wave band by the International Telecommunication Union (ITU). In light of the foregoing, unless otherwise specified, it should be understood that the use of the term "sub-6 GHz" or similar herein can broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include intermediate frequency (IF) frequencies. Furthermore, unless otherwise specified, it should be understood that the use of the term "millimeter wave" or similar herein can broadly refer to frequencies that may include IF frequencies, may be within FR2, or may be within the EHF band.

[0039] 5G NR devices, networks, and systems can be implemented using optimized OFDM-based waveform characteristics. These characteristics can include scalable parameter sets and transmission time intervals (TTIs); a general, flexible framework to effectively multiplex services and features through dynamic, low-latency time-division duplex (TDD) or frequency-division duplex (FDD) designs; and advanced wireless technologies such as massive MIMO, robust millimeter-wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of parameter set technologies in 5G NR, along with the expansion of subcarrier spacing, can effectively address the challenge of operating different services across different spectrums and deployments. For example, in various outdoor and macro coverage deployments implemented with FDD or TDD below 3 GHz, subcarrier spacing can occur at 15 kHz, for example, over bandwidths of 1, 5, 10, 20 MHz, etc. For other various outdoor and small-cell coverage deployments with TDD above 3 GHz, subcarrier spacing can occur at 30 kHz over bandwidths of 80 or 100 MHz. For various other indoor broadband implementations using TDD on the unlicensed portion of the 5 GHz band, subcarrier spacing may occur at 60 kHz over a 160 MHz bandwidth. Finally, for various deployments using millimeter-wave components for TDD transmission at 28 GHz, subcarrier spacing may occur at 120 kHz over a 500 MHz bandwidth.

[0040] 5G NR's scalable parameter set facilitates scalable TTIs to meet diverse latency and Quality of Service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmissions to begin at symbol boundaries. 5G NR also envisions a self-contained integrated subframe design, containing uplink or downlink scheduling information, data, and acknowledgments within the same subframe. Self-contained integrated subframes support communication in unlicensed or contention-based shared spectrum, with adaptive uplink or downlink configuration flexibly configured per cell to dynamically switch between uplink and downlink to meet current communication needs.

[0041] For clarity, certain aspects of the apparatus and technology may be described below with reference to an example 5G NR implementation or in a 5G-centric manner, and 5G terminology may be used as illustrative examples in the sections described below; however, this specification is not intended to be limited to 5G applications.

[0042] Furthermore, it should be understood that in operation, wireless communication networks adapted according to the concepts herein can operate with any combination of licensed or unlicensed spectrum, depending on load and availability. Therefore, it will be apparent to those skilled in the art that the systems, apparatuses, and methods described herein can be applied to other communication systems and applications beyond the specific examples provided.

[0043] Figure 1 This is a block diagram illustrating details of an example wireless communication system. The wireless communication system may include a wireless network 100. The wireless network 100 may, for example, include a 5G wireless network. As those skilled in the art will understand, Figure 1 The components appearing in this may have corresponding counterparts in other network arrangements, including, for example, cellular and non-cellular network arrangements, such as device-to-device, peer-to-peer, or self-organizing network arrangements.

[0044] Figure 1The wireless network 100 shown includes multiple base stations 105 and other network entities. A base station can be a station communicating with a UE, and may also be referred to as an evolved Node B (eNB), a next-generation eNB (gNB), and an access point, etc. Each base station 105 can provide communication coverage for a specific geographic area. In 3GPP, the term "cell" can refer to a specific geographic coverage area of ​​a base station and / or a base station subsystem serving that coverage area, depending on the context in which the term is used. In the implementation of the wireless network 100 herein, base stations 105 can be associated with the same operator or different operators; for example, the wireless network 100 may include multiple operator wireless networks. Furthermore, in the implementation of the wireless network 100 herein, base stations 105 can use one or more of the same frequencies, such as licensed spectrum, one or more bands of unlicensed spectrum, or combinations thereof, as neighboring cells to provide wireless communication. In some examples, a single base station 105 or UE 115 may be operated by more than one network operating entity. In some other examples, each base station 105 and UE 115 may be operated by a single network operating entity.

[0045] Base stations can provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and allow UEs to access the network without restrictions through a service subscription with a network provider. Small cells (such as pico cells) typically cover a relatively small geographic area and allow UEs with a service subscription with a network provider to access the network without restrictions. Small cells (such as femto cells) can also typically cover a relatively small geographic area (such as a home) and, in addition to unrestricted access, provide restricted access through UEs associated with the femto cell (such as UEs in a Closed Subscriber Group (CSG), UEs of users in a home, etc.). A base station for a macro cell can be referred to as a macro base station. A base station for a small cell can be referred to as a small cell base station, pico base station, femto cell, or home base station. Figure 1 In the example shown, base stations 105d and 105e are conventional macro base stations, while base stations 105a-105c are macro base stations enabling one of three-dimensional (3D), full-dimensional (FD), or massive MIMO. Base stations 105a-105c utilize their high-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. Base station 105f is a small cell base station, which can be a home node or a portable access point. A base station can support one or more cells, such as two cells, three cells, four cells, etc.

[0046] Wireless Network 100 can support synchronous or asynchronous operation. For synchronous operation, base stations can have similar frame timings, and transmissions from different base stations can be approximately time-aligned. For asynchronous operation, base stations can have different frame timings, and transmissions from different base stations can be time-disaligned. In some scenarios, the network can be enabled or configured to handle dynamic switching between synchronous and asynchronous operations.

[0047] UE 115 is distributed throughout the wireless network 100, and each UE can be fixed or mobile. It should be understood that although mobile devices are generally referred to as User Equipment (UE) in the standards and specifications issued by 3GPP, those skilled in the art may additionally or otherwise refer to such devices as mobile station (MS), subscriber station, mobile unit, subscriber unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile subscriber station, access terminal (AT), mobile terminal, radio terminal, remote terminal, handheld device, terminal, user agent, mobile client, client, or some other suitable term. In this document, a “mobile” device or UE does not necessarily have the ability to move and can be fixed. Some non-limiting examples of mobile devices, such as implementations that may include one or more of UE 115, include mobile, cellular, smartphone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, laptop computer, personal computer (PC), notebook computer, netbook, smartbook, tablet computer, and personal digital assistant (PDA). Mobile devices can also be “Internet of Things” (IoT) or “Internet of Everything” (IoE) devices such as automobiles or other vehicles, satellite radios, Global Positioning System (GPS) devices, Global Navigation Satellite System (GNSS) devices, logistics controllers, drones, multirotors, quadcopters, smart energy or security devices, solar panels or solar arrays, municipal lighting, water supply or other infrastructure; industrial automation and enterprise equipment; consumer and wearable devices such as glasses, wearable cameras, smartwatches, health or fitness trackers, mammalian implantable devices, gesture tracking devices, medical devices, digital audio players (such as MP3 players), cameras or game consoles, etc.; and digital home or smart home devices such as home audio, video and multimedia equipment, appliances, sensors, vending machines, smart lighting, home security systems or smart meters, etc. In one aspect, a UE can be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE can be a device that does not include a UICC. In some aspects, a UE that does not include a UICC can be referred to as an IoE device. Figure 1The UEs 115a-115d shown are examples of mobile smartphone-type devices accessing the wireless network 100. The UE can be a machine specifically configured for connectivity and communication, including Machine Type Communication (MTC), Enhanced MTC (eMTC), and Narrowband Internet of Things (NB-IoT), etc. Figure 1 The UE 115e-115k shown is an example of various machines configured for accessing communications on the 5G network 100.

[0048] Mobile devices (such as UE 115) can communicate with any type of base station, whether it is a macro base station, pico base station, femto base station, repeater, etc. Figure 1 In this context, a communication link (represented by a lightning bolt) indicates a wireless transmission between the UE and a serving base station (the serving base station is a base station designated to serve the UE on the downlink or uplink) or a desired transmission between base stations, as well as a backhaul transmission between base stations. Backhaul communication between base stations of the wireless network 100 can be performed using wired or wireless communication links.

[0049] In the operation of the 5G network 100, base stations 105a-105c use 3D beamforming and spatial coordination technologies (such as CoMP or multi-connectivity) to serve UEs 115a and 115b. Macro base station 105d performs backhaul communication with base stations 105a-105c and small cell base station 105f. Macro base station 105d also transmits multicast services subscribed to and received by UEs 115c and 115d. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts (such as amber or grey alerts).

[0050] The implemented wireless network 100 supports mission-critical communication, featuring highly reliable and redundant links for mission-critical devices such as UE115e, which is an unmanned aerial vehicle (UAV). Redundant communication links with UE115e include links from macro base stations 105d and 105e, as well as small cell base station 105f. Other machine-type devices, such as UE115f (thermometer), UE115g (smart meter), and UE115h (wearable device), can communicate directly with base stations (such as small cell base station 105f and macro base station 105e) via the wireless network 100, or via a multi-hop configuration through communication with another user device relaying its information to the network (e.g., UE115f communicating temperature measurement information to smart meter UE115g, which then reports it to the network via small cell base station 105f). The 5G network 100 can provide additional network efficiency through dynamic, low-latency TDD or FDD communication in a vehicle-to-vehicle (V2V) mesh network between UEs 115i-115k communicating with macro base station 105e.

[0051] Figure 2 This is a block diagram conceptually illustrating an example design for base station 105 and UE 115. Base station 105 and UE 115 can be... Figure 1 One of the base stations and one of the UEs. For restricted association scenarios (as described above), base station 105 can be... Figure 1 The small cell base station 105f is used, and UE 115 can be UE 115c or 115d operating within the service area of ​​base station 105f. To access small cell base station 105f, these UEs will be included in the list of accessible UEs of small cell base station 105f. Furthermore, base station 105 can be some other type of base station. For example... Figure 2 As shown, base station 105 may be equipped with antennas 234a to 234t, and UE 115 may be equipped with antennas 252a to 252r to facilitate wireless communication.

[0052] At base station 105, transmit processor 220 can receive data from data source 212 and control information from controller 240. The control information can be used for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ (Automatic Repeat Request) Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Enhanced Physical Downlink Control Channel (EPDCCH), or MTC Physical Downlink Control Channel (MPDCCH), etc. Among other examples, the data can be used for PDSCH. Transmit processor 220 can process data and control information, such as encoding and symbol mapping, to obtain data symbols and control symbols respectively. Furthermore, transmit processor 220 can generate reference symbols such as those for primary synchronization signals (PSS) and secondary synchronization signals (SSS), as well as cell-specific reference signals. Transmit (TX) Multiple-Input Multiple-Output (MIMO) processor 230 can perform spatial processing (if applicable) on data symbols, control symbols, or reference symbols, and can provide output symbol streams to modulators (MODs) 232a to 232t. For example, spatial processing performed on data symbols, control symbols, or reference symbols may include precoding. Each modulator 232 may process a corresponding output symbol stream (such as for OFDM) to obtain an output sample stream. Each modulator 232 may additionally or alternatively process the output sample stream to obtain a downlink signal. For example, to process the output sample stream, each modulator 232 may perform conversions to analog, amplify, filter, and upconvert the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a to 232t may be transmitted via antennas 234a to 234t, respectively.

[0053] At UE 115, antennas 252a to 252r can receive downlink signals from base station 105 and can provide the received signals to demodulators (DEMODs) 254a to 254r respectively. Each demodulator 254 can modulate the corresponding received signal to obtain an input sample. For example, to modulate the corresponding received signal, each demodulator 254 can filter, amplify, down-convert, and digitize the corresponding received signal to obtain an input sample. Each demodulator 254 can further process the input sample (e.g., for OFDM) to obtain the received symbols. MIMO detector 256 can obtain the received symbols from demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide the detected symbols. Receiver processor 258 can process the detected symbols, provide decoded data for UE 115 to data sink 260, and provide decoded control information to controller 280. For example, to process the detected symbols, receive processor 258 can demodulate, deinterleave, and decode the detected symbols.

[0054] On the uplink, at UE 115, the transmitting processor 264 can receive and process data from data source 262 (such as for the Physical Uplink Shared Channel (PUSCH)) and control information from controller 280 (such as for the Physical Uplink Control Channel (PUCCH)). Furthermore, the transmitting processor 264 can generate reference symbols for reference signals. Symbols from the transmitting processor 264 can be pre-encoded (if applicable) by the TX MIMO processor 266, further processed by modulators 254a to 254r (such as for SC-FDM), and transmitted to base station 105. At base station 105, the uplink signal from UE 115 can be received by antenna 234, processed by demodulator 232, detected by MIMO detector 236 (if applicable), and further processed by receiving processor 238 to obtain decoded data and control information transmitted by UE 115. Receiving processor 238 can provide the decoded data to data sink 239 and the decoded control information to controller 240.

[0055] Controllers 240 and 280 can respectively direct operations at base station 105 and UE 115. Controller 240 or other processors and modules at base station 105 or controller 280 or other processors and modules at UE 115 can perform or direct various processes that perform the techniques described herein, such as performing or directing... Figure 5 and Figure 7The execution shown herein, or other processes used in the techniques described herein. Memory 242 and 282 may store data and program code for base station 105 and UE 115, respectively. Scheduler 244 may schedule the UE for data transmission on the downlink or uplink.

[0056] In some cases, UE 115 and base station 105 may operate in a shared radio spectrum band, which may include licensed or unlicensed (e.g., contention-based) spectrum. In the unlicensed frequency portion of the shared radio spectrum band, UE 115 or base station 105 may conventionally perform a medium sensing process to compete for access to the spectrum. For example, UE 115 or base station 105 may perform a Listen-Before-Speak or Listen-Before-Transmit (LBT) process, such as Open Channel Assessment (CCA), before communication to determine if a shared channel is available. CCA may include an energy detection process to determine if any other active transmissions are present. For example, the device may infer that a change in the Received Signal Strength Indicator (RSSI) of a power meter indicates that the channel is occupied. Specifically, a signal power concentrated in a specific bandwidth and exceeding a predetermined noise floor may indicate another wireless transmitter. In some implementations, CCA may include the detection of a specific sequence indicating channel usage. For example, another device may transmit a specific preamble before transmitting a data sequence. In some cases, the LBT process may include the wireless node adjusting its own backoff window based on the amount of energy detected on the channel or on acknowledgment or negative acknowledgment (ACK or NACK) feedback for packets it sends as collision proxies.

[0057] Various aspects of this disclosure relate to techniques that enable a user equipment (UE) to keep its state variables synchronized with those of the network (base station) during a communication session. For example, state variables may be associated with the UE's Radio Link Control (RLC) Entity Acknowledgment Mode (AM) window state variables or Packet Data Convergence Protocol (PDCP) Entity window state variables. In some aspects, the UE may establish an entity such as an RLC entity or PDCP entity to join a communication session, such as a unicast, multicast, or broadcast communication session with the base station. Furthermore, the UE may initialize one or more state variables associated with a communication window such as a sliding window. Based on the mode (such as UM mode or AM mode) of the successfully configured entity or RLC entity, the base station may send a Control Protocol Data Unit (PDU) to the UE, which includes a set of one or more current values ​​of one or more state variables (maintained by the base station), enabling the UE to update its state variables to synchronize the communication window of the communication session with the base station. In some implementations, the control PDU may be sent without an assigned RLC sequence number (SN).

[0058] In some aspects, during a communication session, the UE can perform a handover operation to a target cell associated with a base station and can re-establish entities. Based on the completion of the handover operation, the base station associated with the target cell can send a control PDU (without an assigned RLC SN) to the UE, enabling the UE to manage its state variables and maintain synchronization between the UE's entities and the entities of the base station associated with the target cell.

[0059] In some aspects, the base station can send one or more synchronization PDUs to the UE during a communication session. For example, the base station can periodically send synchronization PDUs to the UE. In some implementations, each synchronization PDU may include an RLC SN or be sent along with an RLC SN, and may include one or more current values ​​of one or more state variables (maintained by the base station) to enable the UE to determine whether to update its state variables to synchronize the communication window of the communication session with the base station to avoid dropping received packets. Furthermore, if the UE does not receive valid packets associated with an entity (such as an RLC entity or PDCP entity) for a period of time, the communication window is determined to be "stagnant," and the UE re-establishes the entity, which may lead to an interruption of the UE's reception of the communication session. Therefore, one or more synchronization PDUs enable the UE to maintain synchronization with the base station's communication window and prevent the communication window from becoming stagnant.

[0060] Specific implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. In some aspects, this disclosure provides techniques for managing one or more state variables, such as state variables associated with an RLC AM entity, RLC UM entity, or PDCP entity. For example, a base station can maintain various state variables and provide the UE with a value of each of one or more state variables to enable the UE to maintain synchronization with the base station. For example, the value of the state variable can enable the UE to synchronize with the base station based on the UE establishing an RLC AM entity or PDCP entity and joining a communication session, or based on the UE performing a handover operation and re-establishing an RLC AM entity, RLC UM entity, or PDCP entity. In addition to providing the value of the state variable based on the UE joining a communication session or performing a handover operation, the base station can also provide the value of the state variable at one or more other times during the communication session. By providing the UE with the value of the state variables maintained by the base station, the UE can manage synchronization with the base station and experience fewer interruptions during the communication session, thereby improving the user experience.

[0061] Figure 3This is a block diagram illustrating an example wireless communication system 300 supporting the management of state variables, based on one or more aspects. In some examples, the wireless communication system 300 may implement aspects of the wireless network 100. The wireless communication system 300 includes a UE 115, a base station 105, a base station 360, and a content provider 352. Although one UE 115 and two base stations 105 and 360 are shown, in some other implementations, the wireless communication system 300 may typically include multiple UEs 115 and may include one or more base stations. In some implementations, base station 105 may be associated with a first cell, and base station 360 may be associated with a second cell. In some other implementations, base station 105 is associated with both a first cell and a second cell.

[0062] UE 115 may include various components (such as architecture, hardware components) for performing one or more of the functions described herein. For example, these components may include one or more processors 302 (collectively, “processor 302”), one or more memory devices 304 (collectively, “memory 304”), one or more transmitters 316 (collectively, “transmitter 316”), one or more receivers 318 (collectively, “receiver 318”), and RLC entity 320. Processor 302 may be configured to execute instructions stored in memory 304 to perform the operations described herein. In some implementations, processor 302 includes or corresponds to one or more of receive processor 258, transmit processor 264, and controller 280, and memory 304 includes or corresponds to memory 282.

[0063] Memory 304 includes or is configured to store one or more state variables 306 (collectively referred to as "state variables 306") and one or more initial values ​​308 (collectively referred to as "initial values ​​308"). State variables 306 may be associated with operations or communications via RLC entity 320, such as a communication window. For example, state variables 306 may include window size, bottom edge value, top edge value, or a combination thereof.

[0064] State variable 306 may include or correspond to data transmission, such as UM data transmission or AM data transmission. For example, UE 115 may maintain the current value of state variable 306 during a communication session. In some implementations, UE 115 may initiate a communication session and set state variable 306 to an initial value 308. For example, UE 115 may set state variable 306 to an initial value 308 based on the establishment or re-establishment of RLC entity 320. Additionally or alternatively, during a communication session, UE 115 may adjust the value of state variable 306 as further described herein.

[0065] The status variable 306 can be set to a non - negative integer. As an illustrative, non - limiting example, the status variable 306 is described herein with reference to AM data transmission. Although described herein with reference to AM data transmission, it should be noted that such description is not intended to be limiting and in some implementations, the status variable 306 can be associated with UM data transmission. Associated with AM data transmission, for a 12 - bit SN, the status variable 306 can have values from 0 to 4095, or for an 18 - bit SN, can have values from 0 to 262143. The UE 115 can perform one or more arithmetic operations on the status variable 306 related to AM data transmission based on the AM modulus. For example, for a 12 - bit SN, the final value = [value from arithmetic operation] modulo 4096, and for an 18 - bit SN, the final value = [value from arithmetic operation] modulo 262144. Note that when performing arithmetic comparisons of the status variable 306 or SN values, the modulo base can be used.

[0066] TX_Next_Ack and RX_Next can be assumed to be the modulo bases for the transmit and receive sides of the RLC entity 320 (such as an AM RLC entity), respectively. The modulo base can be subtracted from all the values involved, and then an absolute comparison can be made. For illustration, RX - Next <= SN < RX - Next + AM_Window_Size can be evaluated as [RX_Next – RX_Next] modulo 2 [sn -FieldLength] modulo <= [SN – RX - Next] modulo 2 [SN-FieldLengh] modulo < [RX_Next + AM_Window_Size – RX_Next] modulo 2 [sn-FieldLength] modulo), where for a 12 - bit SN and an 18 - bit SN, the sn - FieldLength is 12 or 18, respectively.

[0067] On the transmitting side of RLC entity 320, such as an AM RLC entity, a state variable 306 may be maintained, which may include a first state variable, a second state variable, a third state variable, or a combination thereof. For example, the first, second, and third state variables may include an acknowledgment state variable (TX_Next_Ack), a transmit state variable (TX_Next), and a polling transmit state variable (POLL_SN), respectively. The first state variable (such as the acknowledgment state variable (TX_Next_Ack)) may have a value for the SN of the next RLC SDU to be received in sequence with a positive acknowledgment and may be used as the lower edge of the transmit window. The first state variable may be initialized to 0 and may be updated when the RLC entity receives a positive acknowledgment for an RLCSDU with SN = TX_Next_Ack. The second state variable (such as the transmit state variable (TX_Next)) may have a value for the SN to be assigned to the next newly generated Acknowledgment Mode Data (AMD) PDU. The second state variable may be initialized to 0 and may be updated when the RLC entity constructs an AMD PDU with SN = TX_Next and includes the RLC SDU or the last segment of the RLC SDU. The third state variable (such as the polling send state variable (POLL_SN)) can have the value of the highest SN of the AMD PDU submitted to the lower-level AMD PDU when POLL_SN is set. The third state variable can be initialized to 0.

[0068] In addition, the transmitting side of an RLC entity (such as an AM RLC entity) can maintain one or more counters. These counters may include a first counter, a second counter, a third counter, or a combination thereof. The first, second, and third counters may include a PDU_WITHOUT_POLL counter, a BYTE_WITHOUT_POLL counter, and a RETX_COUNT counter, respectively. The first counter (such as the PDU_WITHOUT_POLL counter) can be initialized to 0 and configured to count the number of AMD PDUs transmitted since the most recent polling bit was sent. The second counter (such as the BYTE_WITHOUT_POLL counter) can be initialized to 0 and configured to count the number of data bytes transmitted since the most recent polling bit was sent. The third counter (such as the RETX_COUNT counter) can be configured to count the number of retransmissions of an RLC Service Data Unit (SDU) or RLC SDU segment. In some implementations, each RLC SDU may maintain one RETX_COUNT counter.

[0069] The receiving side of RLC entity 320 can maintain state variable 306, which may include a fourth state variable, a fifth state variable, a sixth state variable, a seventh state variable, or a combination thereof. For example, the fourth, fifth, sixth, and seventh state variables may respectively include a receive state variable (RX_Next), a t-Reassembly state variable (RX_Next_Status_Trigger), a maximum STATUS transmit state variable (RX Highest_Status), and a highest receive state variable (RX_Next_Highest). The fourth state variable (such as the receive state variable (RX_Next)) may have the value of the SN following the last fully received RLC SDU in the sequence and may be used as the lower edge of the receive window. The fourth state variable may be initially set to 0 and may be updated when RLC entity 320 receives an RLC SDU with SN = RX_Next. The fifth state variable (such as the t-Reassembly state variable (RX_Next_Status_Trigger)) may have the value of the SN following the SN of the RLC SDU that triggers t-Reassembly. The sixth state variable (such as the highest STATUS transmit state variable (RX_Highest_Status)) can have the highest possible value of the SN, which can be indicated by "ACK_SN" when a STATUS PDU needs to be constructed. The sixth state variable can be initialized to 0. The seventh state variable (such as the highest receive state variable (RX_Next_Highest)) can have the value of the SN following the SN of the RLC SDU with the highest SN among the received RLC SDUs. The seventh state variable can be initialized to 0.

[0070] Transmitter 316 is configured to transmit reference signals, control information, and data to one or more other devices, and receiver 318 is configured to receive reference signals, synchronization signals, control signals, and data from one or more other devices. For example, transmitter 316 may transmit signaling, control information, and data to base station 105, and receiver 318 may receive signaling, control information, and data from base station 105. In some implementations, transmitter 316 and receiver 318 may be integrated into one or more transceivers. Additionally or alternatively, transmitter 316 or receiver 318 may include or correspond to a reference signal. Figure 2The UE 115 described may include one or more components. For example, transmitter 316 may include or correspond to antenna 234a-t, modulator and demodulator 232a-t, transmit processor 220, TX MIMO processor 230, or combinations thereof. As another example, receiver 318 may include or correspond to antenna 234a-t, modulator and demodulator 232a-t, MIMO detector 236, receive processor 238, or combinations thereof.

[0071] RLC entity 320 is configured to set and update state variable 306. UE 115 can establish RLC entity 320 based on an upper-layer request. For example, UE 115 can establish RLC entity 320 and set state variable 306 to its initial value 308. Furthermore, UE 115 can re-establish RLC entity 320 based on an upper-layer re-establishment request. For example, to re-establish RLC entity 320, the UE can discard all RLC SDUs, RLC SDU segments, and RLC PDUs (if any). Additionally or alternatively, to re-establish RLC entity 320, UE 115 can stop and reset one or more timers, reset one or more state variables to their initial values, or a combination thereof. For illustration, UE 115 can stop and reset all timers and reset all state variables to their initial values. Additionally, RLC entity 320 can be configured to have modes such as Transparent Mode (TM), Unacknowledged Mode (UM), or AM. In some implementations, state variable 306 may be associated with the communication window used by RLC entity 320 in UM (such as RLC UM entity). In some other implementations, state variable 306 may be associated with the communication window used by RLC entity 320 in AM (such as RLC AM entity).

[0072] Base station 105 may include various components (such as architecture, hardware components) for performing one or more of the functions described herein. For example, these components may include one or more processors 352 (collectively, "processor 352"), one or more memory devices 354 (collectively, "memory 354"), one or more transmitters 356 (collectively, "transmitter 356"), and one or more receivers 358 (collectively, "receiver 358"). Processor 352 may be configured to execute instructions stored in memory 354 to perform the operations described herein. In some implementations, processor 352 includes or corresponds to one or more of receive processor 238, transmit processor 220, and controller 240, and memory 354 includes or corresponds to memory 242.

[0073] Memory 354 includes or is configured to store one or more state variables 355 (hereinafter collectively referred to as "state variables 355") and an initial value 308. State variables 355 may include or correspond to state variable 306. For example, base station 105 may maintain the current value of state variable 355 during a communication session. In some implementations, base station 105 may initiate a communication session and set state variable 355 to the initial value 308. Additionally or alternatively, during a communication session, base station 105 may adjust the value of state variable 355 such that base station 105 maintains the current value of state variable 355.

[0074] Transmitter 356 is configured to transmit reference signals, synchronization signals, control information, and data to one or more other devices, and receiver 358 is configured to receive reference signals, control information, and data from one or more other devices. For example, transmitter 356 may transmit signaling, control information, and data to UE 115, and receiver 358 may receive signaling, control information, and data from UE 115. In some implementations, transmitter 356 and receiver 358 may be integrated into one or more transceivers. Additionally or alternatively, transmitter 356 or receiver 358 may include or correspond to a reference signal. Figure 2 Describe one or more components of base station 105. For example, transmitter 356 may include or correspond to antenna 252a-r, modulator and demodulator 254a-r, transmit processor 264, TX MIMO processor 266, or combinations thereof. As another example, receiver 358 may include or correspond to antenna 252a-r, modulator and demodulator 254a-r, MIMO detector 256, receive processor 258, or combinations thereof.

[0075] Base station 360 may include one or more components as described in reference base station 105. Additionally or alternatively, base station 360 may be configured to perform one or more operations as described in reference base station 105.

[0076] Content provider 362 is configured to provide content, such as video content, audio content, or a combination thereof. This content may be associated with a communication session, such as a communication session established with UE 115. For example, UE 115 may establish a communication session with content provider 352 via one or more base stations (such as base station 105 or base station 360), such as a unicast communication session, a multicast communication session, or a broadcast communication session. Although wireless communication system 300 is described as having content provider 362 separate from base station 105, in other implementations, base station 105 may include content from content provider 362 or content provider 262. Furthermore, although wireless communication system 300 is described as including content provider 362, in other implementations, wireless communication system 300 may not include content provider 362.

[0077] In some implementations, the wireless communication system 300 implements a 5G New Radio (NR) network. For example, the wireless communication system 300 may include multiple 5G-capable UEs 115 and multiple 5G-capable base stations 105, such as UEs and base stations configured to operate according to 5G NR network protocols such as those defined by 3GPP.

[0078] During the operation of the wireless communication system 300, the UE 115 can establish an RLC entity 320 and configure the RLC entity's mode 320. For example, to configure the RLC entity, the UE 115 can establish the RLC entity 320 to join an ongoing communication session, such as a unicast communication session, a multicast communication session, or a broadcast communication. In some implementations, the communication session includes a multicast data session. Additionally or alternatively, to establish the RLC entity, the UE 115 can set a state variable 306 to an initial value 308. The state variable 306 can be associated with a communication window of the communication session, such as a Tx window, an Rx window, or a combination thereof. For example, the state variable can include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, at least one of the first to seventh state variables, or a combination thereof. The initial value 308 can be based on a criterion, equal to zero, or a combination thereof. Additionally or alternatively, the initial value 308 can be included in or indicated by a Radio Resource Control (RRC) message sent by the base station 105 and received by the UE 115. In some implementations, UE 115 can initiate the establishment of a communication session after configuring RLC entity 320.

[0079] In some implementations, base station 105 may also establish an RLC entity associated with the communication session. In some implementations, the transmitting RLC entity of base station 105 may be synchronized with the RLC entity 320 of UE 115 (such as a receiving RLC entity). Additionally or alternatively, the receiving RLC entity of base station 105 may be synchronized with the RLC entity 320 of UE 115 (such as a transmitting RLC entity). The synchronization of the RLC entity of base station 105 and the RLC entity 320 of UE may include the synchronization of the temporal movement of the RLC sliding window, such that the RLC sliding window of base station 105 and the RLC sliding window of UE 115 completely or at least partially overlap in time.

[0080] After configuring RLC entity 320, base station 105 can generate control message 370, such as an RLC control message. Control message 370 may include an indication of a first value 371 of state variable 355 maintained by base station 105 and associated with the communication window of the communication session. The first value 371 enables synchronization of the communication window of UE 115 and may differ from the initial value 308, the value of state variable 306, or both. After generating control message 370, base station 105 sends control message 370 to UE 115. In some implementations, control message 370, such as the first value 371, may include or indicate the initial value 308.

[0081] In some implementations, control message 370 includes a first RLCPDU sent to UE 115 after the establishment of RLC entity 320. For example, control message 370 may include a synchronization PDU that includes this indication. In some implementations, control message 370 may be included in an RRC message. Additionally or alternatively, control message 370 may include a Control PDU Type (CPT) field, which includes one or more bits. The one or more bits may indicate the type as an RLC control PDU or a synchronization PDU including a first value 371. Additionally or alternatively, control message 370 sent by base station 105 may be independent of the RLC SN. Alternatively, control message 370 may not include the RLC SN.

[0082] UE 115 receives a control message 370 including an indication of a first value 371. UE 115 can set a state variable 306 based on the control message 370. For example, UE 115 can set the state variable 306 from an initial value 308 or a current value to the first value 371. Setting the state variable 306 to the first value 371 allows the communication window of UE 115 (associated with RLC entity 320) to synchronize with base station 105. After setting the state variable 306, UE 115 can receive or send packets associated with a communication session within the communication window based on the state variable 306. For illustration, UE 115 can receive packets 372 associated with a communication session from base station 105.

[0083] In some implementations, UE 115 can perform a handover operation from base station 360 to base station 115. For example, UE 115 can send a handover request 378 to base station 360 to initiate a handover operation from a first cell associated with base station 360 to a second cell (such as a target cell) associated with base station 105. For illustration, UE 115 may have already established an RLC entity and joined a communication session with base station 360, and can perform a handover operation to continue the communication session via base station 105.

[0084] Following a handover operation, UE 115 can re-establish RLC entity 320 (such as an RLC UM entity or an RLC AM entity) based on the completion of the handover operation to the target cell (such as base station 105). After RLC entity 320 is re-established, UE 115 can receive control messages 370, such as RLC control messages. For example, in some implementations, UE 115 can receive initial state variables such as initial value 308 in the RRC message. In some implementations, the control message 370 sent by base station 105 after completing the handover operation may include an RLC data PDU, which includes the allocated RLC SN. Alternatively, the control message 370 sent by base station 105 after completing the handover operation may be independent of the RLC SN. In other words, control message 370 may not include the RLC SN. In some implementations, after RLC entity 320 is re-established, UE 115 can receive a message including the SN and can determine or generate state variables based on the received SN.

[0085] Based on the control message 370 received after the handover operation is completed, UE 115 can set state variable 306. After setting state variable 306, UE 115 can receive or send packets associated with the communication session within the communication window based on state variable 306. For illustration, UE 115 can receive packet 372 associated with the communication session from base station 105.

[0086] In some implementations, base station 105 can determine whether UE 115 has joined a communication session or completed a handover operation. Based on the determination that the UE has joined a communication session or completed a handover operation, base station 105 can generate control message 370 and send it to UE 115.

[0087] In some implementations, base station 105 may generate one or more synchronization messages, such as one or more synchronization PDUs, during a communication session. For example, one or more synchronization messages may include a representative synchronization message 374. Each of the one or more synchronization messages may include a corresponding indication of an update to the UE 115's state variable 306, a corresponding sequence number, or a combination thereof. For illustration, synchronization message 374 may include a second value 375 of state variable 355 maintained by base station 105 and associated with the communication window of the communication session. The second value 375 allows the communication window of UE 115 to be synchronized and may differ from the value of state variable 306. For example, UE 115 may experience fading conditions, and synchronization message 374 including the second value 375 allows UE 115 to quickly adjust state variable 306 and return synchronously with the ongoing communication session (such as multicast service). In some implementations, synchronization message 374 may include an SN number 377.

[0088] After generating a synchronization message such as synchronization message 374, base station 105 can send the synchronization message to UE 115. UE 115 can receive the synchronization message and determine whether to update state variable 306 based on the indication of a corresponding update to state variable 306. For example, UE 115 can determine to update state variable 306 and can update the state variable based on the received synchronization message, such as based on the received second value 375. In some implementations, base station 105 periodically sends synchronization messages to UE 115 to enable UE 115 to maintain synchronization between its communication window and base station 105. In some implementations, synchronization message 374 can be a control PDU included in or coupled to (e.g., carried on) a data PDU.

[0089] Although the synchronization of the command window has been described and maintained based on control message 370 and synchronization message 374, either control message 370 or synchronization message 374 can be used without the other. Furthermore, although it has been described that control message 370 is provided based on UE 115 joining a communication session and completing a handover operation, in other implementations, control message 370 can be provided for either joining a communication session or completing a handover operation, rather than the other.

[0090] For reference Figure 3As described above, this disclosure provides techniques for managing state variable 306. In some aspects, this disclosure provides management of state variable 306 by providing a control message 370 that includes a first value 371. For example, control message 370 may be provided based on the establishment or re-establishment of RLC entity 320 at UE 115. Additionally or alternatively, this disclosure provides management of state variable 306 by providing a synchronization message 374 that includes a second value 375. Each of control message 370 and synchronization message 374 enables UE 115 to maintain synchronization with base station 115. By maintaining synchronization between UE 115 and base station 105, UE 115 can experience fewer interruptions during communication sessions, thereby providing a positive user experience.

[0091] Figure 4 This is a block diagram illustrating an example wireless communication system 400 that supports the management of state variables, based on one or more aspects. In some examples, wireless communication system 400 may implement aspects of wireless network 100 or wireless communication system 300. Wireless communication system 400 includes UE 115, base station 105, base station 360, and content provider 352. Although one UE 115 and two base stations 105 and 360 are shown, in some other implementations, wireless communication system 400 may typically include multiple UEs 115 and may include one or more base stations. In some implementations, base station 105 may be associated with a first cell, and base station 360 may be associated with a second cell. In some other implementations, base station 105 is associated with both a first cell and a second cell.

[0092] UE 115 may include various components (such as architecture, hardware components) for performing one or more of the functions described herein. For example, these components may include processor 302, memory 304, transmitter 316, receiver 318, and PDCP entity 422. Processor 302 may be configured to execute instructions stored in memory 304 to perform the operations described herein. In some implementations, processor 302 includes or corresponds to one or more of receive processor 258, transmit processor 264, and controller 280, and memory 304 includes or corresponds to memory 282.

[0093] Memory 304 includes or is configured to store one or more state variables 406 (hereinafter collectively referred to as "state variables 406") and one or more initial values ​​408 (hereinafter collectively referred to as "initial values ​​408"). In some implementations, state variables 406 and initial values ​​408 may include or correspond to state variables 306 and initial values ​​308, respectively. State variables 406 may be associated with operations or communications via PDCP entity 422, such as a communication window. For example, state variables 406 may include window size, bottom edge value, top edge value, or a combination thereof.

[0094] State variable 406 may include or correspond to data transmission, such as PDU transmissions associated with the PDCP layer. For example, UE 115 may maintain the current value of state variable 406 during a communication session. In some implementations, UE 115 may initiate a communication session and set state variable 406 to an initial value 408. For example, UE 115 may set state variable 406 to an initial value 408 based on the establishment or re-establishment of PDCP entity 422. Additionally or alternatively, UE 115 may adjust the value of state variable 406 during a communication session, as further described herein.

[0095] State variable 406 can be set to a non-negative integer. As an illustrative, non-restrictive example, this document describes state variable 406 with reference to PDCP PDU data transmission. State variable 406 can have values ​​from 0 to an upper limit, such as [2^32-1]. Additionally or alternatively, PDCP data PDUs can be numbered integer sequence numbers (SNs) that cycle through the field: 0 to [2[pdcp-SN-size]-1]. In some implementations, pdcp-SN-size can be based on or equal to an upper limit.

[0096] The transmitting side of PDCP entity 422 can maintain state variable 406, which may include a first state variable. For example, the first state variable may include a transmit (Tx) next state variable (TX_Next). The first state variable (such as the Tx next state variable (TX_Next)) may have a value indicating the next PDCP SDU to be transmitted. The first state variable can be initially set to 0.

[0097] The receiving side of PDCP entity 422 can maintain state variable 306, which may include a second state variable, a third state variable, a fourth state variable, or a combination thereof. For example, the second, third, and fourth state variables may include a receive (Rx) state variable (RX_Next), an Rx delivery state variable (RX_DELIV), and an Rx reordering state variable (RX_REORD), respectively. The second state variable (such as the Rx state variable (RX_Next)) may have a count indicating the next PDCP SDU expected to be received. The second state variable may be initially set to 0. The third state variable (such as the Rx delivery state variable (RX_DELIV)) may have a count indicating the first PDCP SDU that has not been delivered to the upper layer but is still waiting. The third state variable may be initially set to 0. The fourth state variable (such as the Rx reordering state variable (RX_REORD)) may have a count indicating the PDCP data PDU that triggered reordering (e.g., t-reordering).

[0098] PDCP entity 422 is configured to set and update state variable 406. UE 115 may establish PDCP entity 422 as part of a stack. For example, UE 115 may establish a stack or PDCP entity 422 based on an upper-layer request. This stack may include or correspond to the Serving Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, RLC layer, Media Access Control (MAC) layer, or Physical (PHY) layer. For illustration, UE 115 may establish PDCP entity 422 and may set state variable 306 to an initial value 308. Additionally or alternatively, UE 115 may establish RLC entity 320 based on an upper-layer request. In some implementations, UE 115 may additionally re-establish PDCP entity 422 (or RLC entity 320) based on an upper-layer re-establishment request.

[0099] Base station 105 may include various components (such as architecture, hardware components) for performing one or more of the functions described herein. For example, these components may include processor 352, memory 354, transmitter 356, and receiver 358. Processor 352 may be configured to execute instructions stored in memory 354 to perform the operations described herein. In some implementations, processor 352 includes or corresponds to one or more of receiver processor 238, transmitter processor 220, and controller 240, and memory 354 includes or corresponds to memory 242.

[0100] Memory 354 includes or is configured to store one or more state variables 455 (hereinafter collectively referred to as "state variables 455") and an initial value 408. State variable 455 may include or correspond to state variable 355. Additionally or alternatively, state variable 455 may include or correspond to state variable 406. For example, base station 105 may maintain the current value of state variable 455 during a communication session. In some implementations, base station 105 may initiate a communication session and set state variable 455 to the initial value 408. Additionally or alternatively, during a communication session, base station 105 may adjust the value of state variable 455 such that base station 105 maintains the current value of state variable 455.

[0101] In some implementations, base station 105 may include a PDCP entity. The PDCP entity may include or correspond to PDCP entity 422. The transmitting PDCP entity of base station 105 may be configured to perform operations associated with transmitting data to a receiving PDCP entity (such as PDCP entity 422) of UE 115. Additionally or alternatively, the receiving PDCP entity of base station 105 may be configured to perform operations associated with receiving data from a transmitting PDCP entity (such as PDCP entity 422) of UE 115.

[0102] In some implementations, the wireless communication system 400 implements a 5G NR network. For example, the wireless communication system 400 may include multiple 5G-capable UEs 115 and multiple 5G-capable base stations 105, such as UEs and base stations configured to operate according to 5G NR network protocols such as those defined by 3GPP.

[0103] During the operation of the wireless communication system 400, UE 115 may establish PDCP entity 422. For example, to configure PDCP entity 422, UE 115 may establish PDCP entity 422 to join an ongoing communication session, such as a unicast communication session, a multicast communication session, or a broadcast communication session. In some implementations, the communication session includes a multicast data session. In such an implementation, UE 115 may configure a multicast bearer (MRB) that includes or corresponds to a user plane stack with one or more layers, such as the SDAP layer, PDCP layer, RLC layer, MAC layer, PHY layer, or a combination thereof. Additionally or alternatively, to establish PDCP entity 422, UE 115 may set state variable 406 to an initial value 408. State variable 406 may be associated with a communication window of the communication session, such as a Tx window, an Rx window, or a combination thereof. For example, state variable may include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, at least one of the first to fourth state variables, or a combination thereof. The initial value 408 can be based on a standard, equal to zero, or a combination thereof. Additionally or alternatively, the initial value 408 can be included in or indicated by an RRC message sent by base station 105 and received by UE 115. In some implementations, UE 115 can initiate the establishment of a communication session after configuring PDCP entity 422.

[0104] In some implementations, base station 105 may also establish a PDCP entity associated with the communication session. In some implementations, the transmitting PDCP entity of base station 105 may be synchronized with the PDCP entity 422 of UE 115 (such as a receiving RLC entity). Additionally or alternatively, the receiving PDCP entity of base station 105 may be synchronized with the PDCP entity 422 of UE 115 (such as a transmitting PDCP entity). The synchronization of the PDCP entity of base station 105 and the PDCP entity 422 of UE 115 may include the synchronization of the temporal movement of the PDCP sliding window, such that the PDCP sliding window of base station 105 and the PDCP sliding window of UE 115 completely or at least partially overlap in time.

[0105] After configuring PDCP entity 422, base station 105 can generate control message 470, such as a PDCP control message. In some implementations, the generation or transmission of control message 470 may be part of the establishment of a communication session. Additionally or alternatively, control message 470 may be included in an RRC message. For illustration, base station 105 may generate an RRC message that includes control message 370, control message 470, or a combination thereof. Control message 470 may include an indication of a first value 471 of state variable 455 maintained by base station 105 and associated with the communication window of the communication session. The first value 471 may enable the communication window of UE 115 to be synchronized and may differ from the initial value 408, the value of state variable 406, or both. After generating control message 470, base station 105 sends control message 470 to UE 115. In some implementations, control message 470, such as the first value 471, may include or indicate the initial value 408.

[0106] In some implementations, control message 470 includes a first PDCP PDU sent to UE 115 after the establishment of PDCP entity 422. For example, control message 470 may include a synchronization PDU that includes a first value 471. Additionally or alternatively, control message 470 may include an RRC that includes the first value 471. In some implementations, the first value 471 includes a second state variable (Rx_Next), a third state variable (Rx_DELIV), a value associated with the lower edge of the communication window, a value associated with the upper edge of the communication window, or a combination thereof.

[0107] In some implementations, UE 115 can establish a communication session, allowing UE 115 to join an ongoing multicast session, where base station 105 includes a PDCP entity with the current value of state variable 455. When UE 115 joins an ongoing multicast session established by UE with state variable 406 set to its initial value 408, a mismatch may occur between UE 115 variable 406 and base station state variable 455, causing the communication window of UE 115 to become out of sync with the communication window of base station 105. When a mismatch occurs causing the communication windows to become out of sync, UE 115 may miss data transmitted by base station 105.

[0108] UE 115 receives a control message 470 including an indication of a first value 471. UE 115 can set a state variable 406 based on the control message 470. For example, UE 115 can set the state variable 406 from an initial value 408 or a current value to the first value 471. Setting the state variable 406 to the first value 471 allows the communication window of UE 115 (associated with PDCP entity 422) to synchronize with base station 105. After setting the state variable 406, UE 115 can receive or transmit data associated with the communication session (such as PDCP data) within the communication window based on the state variable 406. For illustration, UE 115 can receive PDCP data PDUs associated with the communication session from base station 105.

[0109] In some implementations, UE 115 can perform a handover operation from base station 360 to base station 115. For example, UE 115 can send a handover request 478 to base station 360 to initiate a handover operation from a first cell associated with base station 360 to a second cell (such as a target cell) associated with base station 105. For illustration, UE 115 may have already established PDCP entity 422 and joined the communication session with base station 360, and can perform a handover operation to continue the communication session via base station 105.

[0110] Following the handover operation, UE 115 can re-establish PDCP entity 422 based on the completion of the handover operation to the target cell (such as base station 105). After PDCP entity 422 is re-established, UE 115 can receive control messages 470, such as PDCP control messages. For example, UE 115 can receive initial state variables, such as initial state variable 408, in an RRC message. In some implementations, the control message 470 sent by base station 105 after completing the handover operation may include PDCP data PDU. In some implementations, after PDCP entity 422 is re-established, UE 115 can receive messages including the SN and can determine or generate state variables based on the received SN.

[0111] Based on the control message 470 received after the handover operation is completed, UE 115 can set state variable 406 based on the received control message 470. After setting state variable 406, UE 115 can receive or send data associated with the communication session (such as PDCP data) within the communication window based on state variable 406.

[0112] In some implementations, base station 105 can determine whether UE 115 has joined a communication session or completed a handover operation. Based on the determination that the UE has joined a communication session or completed a handover operation, base station 105 can generate control message 470 and send it to UE 115.

[0113] In some implementations, base station 105 may generate one or more synchronization messages, such as one or more synchronization PDUs, during a communication session. For example, one or more synchronization messages may include a representative synchronization message 474. Each of the one or more synchronization messages may include a corresponding indication of an update to the state variable 406 of UE 115. For illustration, synchronization message 374 may include a second value 475 of state variable 45 maintained by base station 105 and associated with the communication window of the communication session. In some implementations, the second value 475 includes a second state variable (Rx_Next), a third state variable (Rx_DELIV), a value associated with the lower edge of the communication window, a value associated with the upper edge of the communication window, or a combination thereof. The second value 475 allows the communication window of UE 115 to be synchronized and may differ from the value of state variable 406. For example, UE 115 may experience fading conditions, and synchronization message 474 including the second value 475 allows UE 115 to quickly adjust state variable 406 and return synchronously with the ongoing communication session (such as multicast service).

[0114] After generating a synchronization message (such as synchronization message 474), base station 105 can send the synchronization message to UE 115. UE 115 can receive the synchronization message and determine whether to update state variable 406 based on the indication of a corresponding update to state variable 406. For example, UE 115 can determine to update state variable 406 and can update the state variable based on the received synchronization message, such as based on the received second value 475. In some implementations, synchronization message 474 may be a control PDU included in or coupled to (such as carried on) a data PDU.

[0115] In some implementations, base station 105 periodically sends synchronization messages to UE 115 to enable UE 115 to maintain synchronization of its communication window with base station 105. Additionally or alternatively, base station 105 may generate or send synchronization message 474 based on the determination of an event. This event may include or correspond to an indication that UE 115 has experienced some fading and returned to good radio conditions, such as having a physical layer that has changed from desynchronized to synchronized, resulting in one or more lost packets and desynchronization of the communication windows of UE 115 and base station 105. As another example, this event may include or correspond to base station 105 determining that retransmissions for the edge of packets have been exhausted, requiring the lower edge of UE 115 to be moved to avoid additional retransmissions. As another example, the determination of the event may be based on load balancing or retransmission policies. As another example, if UE 115 is configured for RLC UM, the event can be determined based on PDCP-level packet loss, even under good radio conditions, if the PDCP window of UE 115 is not aligned with the PDCP window of base station 105. Another example of an event could be PDCP activation starting from a PDCP operation pause.

[0116] Although the synchronization of the command window has been described and maintained based on control message 470 and synchronization message 474, either control message 470 or synchronization message 474 can be used without the other. Furthermore, although it has been described that control message 470 is provided based on UE 115 joining a communication session and completing a handover operation, in other implementations, control message 470 can be provided for either joining a communication session or completing a handover operation, rather than the other.

[0117] In some implementations, control message 470 or synchronization message 474 may include a field for Control PDU Type (CPT), which includes one or more bits. The one or more bits may indicate the type of control information included in control message 470, such as a PDCP control PDU. In some implementations, the one or more bits may have a first value (such as 000) indicating the type of control information included in control message 470, or that synchronization message 474 is a PDCP status report. As another example, the one or more bits may have a second value (such as 001) indicating the type of control information included in control message 470, or that synchronization message 474 is a Spread Robust Header Compression (ROHC) feedback. As yet another example, the one or more bits may have a third value (such as 010) indicating that the type of control information included in control message 470 or synchronization message 474 is a synchronization PDU, such as a PDCP MRB synchronization PDU.

[0118] For reference Figure 4 As described above, this disclosure provides techniques for managing state variable 406. In some aspects, this disclosure provides management of state variable 406 by providing a control message 470 that includes a first value 471. For example, control message 470 may be provided based on the establishment or re-establishment of PDCP entity 422 at UE 115. Additionally or alternatively, this disclosure provides management of state variable 406 by providing a synchronization message 474 that includes a second value 475. Each of control message 470 and synchronization message 474 enables UE 115 to maintain synchronization with base station 115. By maintaining synchronization between UE 115 and base station 105, UE 115 can experience fewer interruptions during communication sessions, thereby providing a positive user experience.

[0119] Figure 5 This is a flowchart illustrating an example process 500 that supports the management of state variables, based on one or more aspects. The operation of process 500 can be performed by the UE, as described in the above reference. Figures 1 to 4 The UE 115 described or referenced Figure 6 The UE is described. For example, the example operation of process 500 (also referred to as a "box") enables UE 115 to manage state variables.

[0120] In block 502, the UE initializes a set of state variables to a first set of initial values. This set of state variables is associated with the synchronization of the communication window of the communication session. For example, this set of state variables may include or correspond to state variables 306 and 406. The first set of initial values ​​may include or correspond to initial values ​​308 or 408. The communication session may include a unicast communication session, a multicast communication session, or a broadcast communication session. For example, the communication session may be a multicast communication session.

[0121] In some implementations, the communication window may include a Tx window, an Rx window, or a combination thereof. Additionally or alternatively, this set of state variables includes the window size of the communication window, the bottom edge value of the communication window, the top edge value of the communication window, or a combination thereof. In some implementations, this set of state variables includes the window size of the communication window and either the bottom edge value or the top edge value of the communication window.

[0122] In block 504, the UE receives a control message that includes an indication of a second set of current values ​​associated with the corresponding state variables of the set of state variables. At least one current value differs from the corresponding initial value. For example, the control message and the indication may include or correspond to control message 370 and first value 371, or control message 470 and first value 471, respectively. In some implementations, the indication of the second set of current values ​​may be generated by a base station (such as base station 105) based on one or more state variables maintained by the base station.

[0123] In box 506, the UE sets the group of state variables to the second group of current values ​​to synchronize the communication window with the communication session. In some implementations, setting the group of state variables based on an instruction includes adjusting the group of state variables from the first group of initial values ​​to the second group of current values ​​or adjusting the group of state variables to a third group of values ​​based on the second group of current values.

[0124] In some implementations, after setting the set of state variables, the UE receives or sends packets associated with the communication session within a synchronized communication window. For example, the packets may include or correspond to packet 372.

[0125] In some implementations, this set of state variables corresponds to an RLC AM entity. The UE can configure the RLC AM entity, which may include setting this set of state variables to a corresponding set of initial values. The corresponding set of initial values ​​may be based on a standard. In some implementations, at least one of the corresponding set of initial values ​​is zero. Additionally or alternatively, the UE may join an ongoing multicast data session corresponding to a communication session.

[0126] In some implementations, control messages include RLC control messages. RLC control messages can be included in the RLC PDU received shortly after the RLC AM entity is configured. Furthermore, the UE can initiate the establishment of a communication session after configuring the RLC AM entity.

[0127] In some implementations, after configuring the RLC AM entity, the UE can perform a handover operation to the target cell. For example, the UE can perform a handover operation from a first cell to a second cell (such as the target cell). The UE can re-establish the RLC AM entity based on the completion of the handover operation to the target cell. In some such implementations, RLC control messages are received after the RLCAM entity has been re-established.

[0128] In some implementations, the control message includes a synchronization PDU, which includes an indication. The UE may, in response to receiving one of the one or more synchronization PDUs, update the set of state variables based on the corresponding indication included in the received synchronization PDU. In some implementations, the control message may be included in a data PDU that includes an assigned RLC SN. The RLC SN may include or correspond to sequence number 377.

[0129] In some implementations, after setting the set of state variables based on an indication and during a communication session, the UE may receive one or more synchronization PDUs. The one or more synchronization PDUs may include or correspond to synchronization messages 374 or 474. In some implementations, each of the one or more received synchronization PDUs includes a corresponding indication for an update to one or more state variables. For example, the indication may include or correspond to a second value 375 or 475. The UE may update the set of state variables based on the indication included in a particular synchronization PDU among the one or more synchronization PDUs. In some implementations, the one or more synchronization PDUs include multiple synchronization PDUs that are periodically transmitted.

[0130] Figure 6 This is a block diagram of an example UE 600 that supports the management of state variables based on one or more aspects. The UE 600 can be configured to perform operations, including referencing... Figure 5 The process described is in box 500. In some implementations, UE 600 includes references. Figure 2 , 3 The structure, hardware, and components shown and described in UE 115 (or UE 4). For example, UE 600 includes a controller 280 that operates to execute logical or computer instructions stored in memory 282, and components that control UE 600 and provide the features and functions of UE 600. Under the control of controller 280, UE 600 transmits and receives signals via radio 601a-r and antenna 252a-r. Radio 601a-r includes various components and hardware, such as... Figure 2 As shown in UE 115, it includes modulator and demodulator 254a-r, MIMO detector 256, receiver processor 258, transmitter processor 264 and TX MIMO processor 266.

[0131] As shown in the figure, memory 282 may include state variable logic 602 and entity logic 603. State variable logic 602 can be configured to set, adjust, update, or synchronize one or more state variables, such as state variable 306 or 406. Entity logic 603 can be configured to receive or process one or more received messages, such as control messages 370 or 470, packets 372, synchronization messages 374 or 474, or combinations thereof. UE 600 can receive signals from or send signals to one or more network entities, such as... Figures 1 to 4 Base station 105 Figure 3 360 base station or Figure 8 The base station shown.

[0132] In some implementations, UE 600 can be configured to perform Figure 5The process 500. For illustration, UE 600 can execute state variable logic 602 and entity logic 603 stored in memory 282 under the control of controller 280. The execution environment of state variable logic 602 provides the functionality to perform at least the operations in block 502, block 506, or combinations thereof. The execution environment of entity logic 603 provides the functionality to perform at least the operations in block 504.

[0133] Figure 7 This is a flowchart illustrating an example process 700 supporting the management of state variables, based on one or more aspects. The operation of process 700 can be performed by a base station, as shown in the reference above. Figures 1 to 4 The base station 105 described above is referenced. Figure 3 or Figure 4 The described base station 360 or reference Figure 8 The described base station. For example, the example operation of procedure 700 enables the base station to manage state variables.

[0134] In block 702, the base station generates a control message that includes an indication of a set of values ​​for a set of state variables associated with a communication window of the communication session. This set of values ​​synchronizes the communication window and differs from a set of initial values ​​for the set of state variables. For example, the control message may include control message 371, or a corresponding control message. The set of values ​​may include or correspond to a first value 371. The set of initial values ​​may include or correspond to initial values ​​308 or 408.

[0135] In some implementations, control messages are associated with the UE's RLC entity. For example, this entity may include or correspond to RLC entity 320 or PDCP 422. In some implementations, this entity may include an RLC AM entity.

[0136] In block 704, the base station sends a control message to the UE. For example, the UE may include or correspond to UE 115. In some implementations, after sending the control message, the base station may send or receive packets associated with the communication session. For example, the packets may include or correspond to packet 372.

[0137] In some implementations, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session. For example, a communication session can be a multicast communication session. Additionally or alternatively, a communication window includes a Tx window, an Rx window, or a combination thereof. Furthermore, one or more state variables may include the window size of the communication window, the bottom edge value of the communication window, the top edge value of the communication window, or a combination thereof.

[0138] In some implementations, the base station can determine whether the UE has joined a communication session or completed a handover operation. Additionally or alternatively, the base station can send control messages to the UE based on whether it has joined a communication session or completed a handover operation. In some implementations, control messages can be sent to the UE independently of the sequence number associated with the communication session.

[0139] In some implementations, the base station may generate one or more synchronization PDUs. At least one of the one or more synchronization PDUs may include or correspond to synchronization message 374 or 474. In some implementations, each of the one or more synchronization PDUs includes a corresponding indication of an update to one or more state variables. The corresponding indication of the set of state variables may include or correspond to a second value 375 or 475. The base station may transmit one or more synchronization PDUs. In some implementations, the one or more synchronization PDUs may include multiple synchronization PDUs transmitted periodically. Additionally or alternatively, each of the one or more synchronization PDUs may be included in a corresponding RLC data PDU, which includes an RLC SN assigned based on the communication session. The RLC SN may include or correspond to sequence number 377.

[0140] Figure 8 This is a block diagram of an example base station 800 that supports the management of state variables based on one or more aspects. Base station 800 can be configured to perform operations, including referencing... Figure 7 The process described in box 700. In some implementations, base station 800 includes references. Figures 1 to 4 Base station 105 or Figure 3 or Figure 4 The base station 800 is shown and described in the diagram, including its structure, hardware, and components. For example, base station 800 may include a controller 240 that operates to execute logical or computer instructions stored in memory 242, and components that control base station 800 and provide its features and functions. Under the control of controller 240, base station 800 transmits and receives signals via wireless radio 801a-t and antenna 234a-t. Wireless radio 801a-t includes various components and hardware, such as… Figure 2 As shown in the figure for base station 105, it includes modulator and demodulator 232a-t, transmitter processor 220, TX MIMO processor 230, MIMO detector 236 and receiver processor 238.

[0141] As shown in the figure, the memory 242 may include state variable logic 802, message generation logic 803, and transmission logic 804. State variable logic 802 can be configured to set, adjust, and update one or more state variables, such as state variable 355 or 455. Message generation logic 803 can be configured to generate one or more messages, such as control messages 370 or 470, packets 372, synchronization messages 374 or 474, or combinations thereof. Transmission logic 804 can be configured to send one or more messages generated by message generation logic 803. Base station 800 can receive data from one or more UEs (such as...) Figures 1 to 4 UE 115 or Figure 7 The UE 700 receives signals or sends signals to it.

[0142] In some implementations, base station 800 can be configured to perform Figure 7 The process is as follows: For illustration, base station 800 can execute state variable logic 802, message generation logic 803, or transmission logic 804 stored in memory 242 under the control of controller 240. The execution environment of state variable logic 802 provides the functionality to perform at least the operations associated with block 702. The execution environment of message generation logic 803 provides the functionality to perform at least the operations in block 702. The execution environment of transmission logic 804 provides the functionality to perform at least the operations in block 704.

[0143] It should be noted that the reference Figure 5 or Figure 7 One or more boxes (or operations) described can be combined with one or more boxes (or operations) described with reference to another diagram. For example, Figure 5 One or more boxes (or operations) can be associated with Figure 7 A combination of one or more boxes (or actions). As another example, with... Figure 4 or Figure 7 One or more associated boxes can be used with Figure 1 , Figure 2 , Figure 3 or Figure 4 A combination of one or more associated boxes (or operations). Additionally or alternatively, refer to the above. Figure 1 , Figure 2 , Figure 3 or Figure 4 One or more operations described can be compared with the reference Figure 6 or Figure 8 The combination of one or more operations described.

[0144] In some aspects, techniques for implementing state variable management may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In a first aspect, techniques for implementing state variable management may include initializing one or more state variables associated with an RLC entity to a set of one or more corresponding initial values ​​associated with a communication window of a communication session; receiving an RLC control message including an indication of the set of one or more values ​​associated with the one or more state variables, at least one of the set of one or more values ​​being different from at least one corresponding value of the set of one or more initial values; and synchronizing the communication window with the communication session based on setting one or more state variables to the set of one or more values. In some examples, the techniques of the first aspect may be implemented in a method or process. In some other examples, the techniques of the first aspect may be implemented in a wireless communication device, such as a UE or a component of a UE. In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium thereon storing program code that, when executed by a processing unit, is configured to cause a wireless communication device to perform the operations described herein.

[0145] In a second aspect, in conjunction with the first aspect, the technology also includes receiving or sending packets associated with a communication session within a communication window based on synchronization.

[0146] In the third aspect, in conjunction with the first or second aspect, the RLC entity includes the RLC AM entity.

[0147] In the fourth aspect, in combination with one or more of the first to third aspects, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0148] In the fifth aspect, in conjunction with the fourth aspect, communication sessions include multicast communication sessions.

[0149] In the sixth aspect, in conjunction with one or more of the first to fifth aspects, the technology also includes configuring an RLC entity, wherein configuring the RLC entity includes setting one or more state variables to a set of one or more corresponding initial values.

[0150] In the seventh aspect, in conjunction with the sixth aspect, one or more corresponding initial values ​​in this group are based on a standard.

[0151] In the eighth aspect, in conjunction with the sixth or seventh aspect, at least one of the group of one or more corresponding initial values ​​is zero.

[0152] In the ninth aspect, in conjunction with one or more of the sixth to eighth aspects, the technology also includes initiating the establishment of a communication session after the configuration of the RLC entity is completed.

[0153] In the tenth aspect, in conjunction with one or more of the sixth to ninth aspects, the technology also includes joining an ongoing multicast data session corresponding to the communication session.

[0154] In the eleventh aspect, in conjunction with one or more of the sixth to tenth aspects, the RLC control message is included in the RLC PDU received at the next time after the configuration of the RLC entity is completed.

[0155] In the twelfth aspect, in conjunction with one or more of the first to fifth aspects, the technology further includes configuring an RLC entity, performing a handover operation to a target cell after configuring the RLC entity, re-establishing the RLC entity based on the completion of the handover operation to the target cell, and receiving the RLC control message after the RLC entity is re-established.

[0156] In aspect thirteen, in conjunction with aspect twelf, RLC control messages include synchronous PDUs that include indications.

[0157] In the fourteenth aspect, in conjunction with the twelfth or thirteenth aspect, the RLC control message is included in the RLC PDU, which includes the assigned RLC SN.

[0158] In the fifteenth aspect, in conjunction with one or more of the first to fourteenth aspects, setting one or more state variables based on an instruction includes adjusting one or more state variables from one or more corresponding initial values ​​of the group to one or more corresponding values ​​of the first group based on an instruction.

[0159] In the sixteenth aspect, in conjunction with one or more of the first to fifteenth aspects, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0160] In the seventeenth aspect, in conjunction with one or more of the first to sixteenth aspects, the one or more state variables include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0161] In the eighteenth aspect, in conjunction with one or more of the first to seventeenth aspects, one or more state variables include window size and lower edge value or upper edge value.

[0162] In the nineteenth aspect, in conjunction with one or more of the first to eighteenth aspects, the technology further includes setting one or more state variables based on an indication, and, after such setting and during a communication session, receiving one or more synchronization PDUs, each of the one or more received synchronization PDUs including a corresponding indication of a corresponding update to the one or more state variables.

[0163] In the twentieth aspect, in conjunction with the nineteenth aspect, the technology also includes updating the one or more state variables in response to receiving one of the one or more synchronous PDUs, based on a corresponding indication included in the received synchronous PDU.

[0164] In aspect 21, in conjunction with aspects 19 and 20, one or more synchronous PDUs include multiple synchronous PDUs that are periodically transmitted.

[0165] In some aspects, techniques for implementing state variable management may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In a twenty-second aspect, techniques for implementing state variable management may include generating an RLC control message including an indication of one or more values ​​of one or more corresponding state variables associated with a communication window of a communication session, the one or more values ​​of the one or more state variables enabling synchronization of the communication window and differing from the one or more initial values ​​of the one or more corresponding state variables; and sending the RLC control message to the UE. In some examples, the techniques of the first aspect may be implemented in a method or process. In some other examples, the techniques of the first aspect may be implemented in a wireless communication device, such as a base station or a component of a base station. In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium having program code stored thereon, which, when executed by the processing unit, is configured to cause the wireless communication device to perform the operations described herein.

[0166] In aspect 23, in conjunction with aspect 22, the RLC control message is associated with the UE's RLC entity.

[0167] In aspect 24, in conjunction with aspect 22 or aspect 23, the RLC entity includes the RLC AM entity.

[0168] In aspect 26, in conjunction with one or more of aspects 22 to 25, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0169] In aspect 27, in conjunction with one or more of aspects 22 to 26, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0170] In aspect 28, in conjunction with one or more of aspects 22 to 27, the one or more state variables include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0171] In the twenty-ninth aspect, in conjunction with one or more of the twenty-second to twenty-seventh aspects, the technology also includes sending or receiving packets associated with the communication session after sending the RLC control message.

[0172] In the thirtieth aspect, in conjunction with one or more of the twenty-second to twenty-seventh aspects, the technology further includes determining whether the UE has joined a communication session or completed a handover operation, wherein the RLC control message is sent to the UE based on the determination that the UE has joined a communication session or completed a handover operation.

[0173] In the thirty-first aspect, in conjunction with the thirtieth aspect, RLC control messages are sent to the UE independently of the RLC SN associated with the communication session.

[0174] In aspect thirty-two, in conjunction with one or more of aspects twenty-two to twenty-seven, the technology further includes generating one or more synchronous PDUs, each of the one or more synchronous PDUs including a corresponding indication of a corresponding update to one or more state variables, and sending one or more synchronous PDUs.

[0175] In aspect 33, in conjunction with aspect 32, one or more synchronous PDUs include multiple synchronous PDUs that are periodically transmitted.

[0176] In aspect thirty-four, in conjunction with aspect thirty-two or thirty-three, each of one or more synchronous PDUs may be included in the corresponding RLC data PDU, which includes an RLC SN assigned based on the communication session.

[0177] In some aspects, techniques for implementing the management of state variables may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In the thirty-fifth aspect, techniques for implementing the management of state variables may include initializing one or more state variables to a set of one or more corresponding initial values ​​associated with a communication window of a communication session; receiving a control message including an indication of a set of one or more values ​​associated with the one or more state variables, at least one of which differs from at least one corresponding value in the set of one or more initial values; synchronizing the communication window with the communication session based on setting the one or more state variables to the set of one or more values; and receiving or transmitting packets associated with the communication session within the communication window based on the synchronization. In some examples, the techniques of the thirty-fifth aspect may be implemented in a method or process. In some other examples, the techniques of the thirty-fifth aspect may be implemented in a wireless communication device (such as a UE or a component of a UE). In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium thereon storing program code that, when executed by a processing unit, is configured to cause a wireless communication device to perform the operations described herein.

[0178] In aspect 36, in conjunction with aspect 35, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0179] In aspect thirty-seven, in conjunction with aspect thirty-six, communication sessions include multicast communication sessions.

[0180] In aspect thirty-eight, in conjunction with one or more of aspects thirty-five to thirty-seven, one or more state variables are associated with an RLC entity, and control messages include RLC control messages.

[0181] In aspect thirty-nine, in conjunction with aspect thirty-eight, RLC entities include RLC AM entities or RLC UM entities.

[0182] In the fortieth aspect, in conjunction with the thirty-eighth or thirty-ninth aspect, the technology also includes configuring an RLC entity, wherein configuring the RLC entity includes setting one or more state variables to a set of one or more corresponding initial values.

[0183] In the forty-first aspect, in conjunction with the fortieth aspect, one or more corresponding initial values ​​in this group are based on a standard.

[0184] In aspect 42, in conjunction with aspect 40 or 41, at least one of the corresponding initial values ​​in this group is zero.

[0185] In aspect 43, in conjunction with one or more of aspects 40 to 42, the technology also includes initiating the establishment of a communication session after the configuration of the RLC entity is completed.

[0186] In aspect 44, in conjunction with one or more of aspects 40 to 43, the technology also includes joining an ongoing multicast data session corresponding to the communication session.

[0187] In aspect 45, in conjunction with one or more of aspects 40 to 44, the RLC control message is included in the RLC protocol data unit (PDU) received at the next time after the configuration of the RLC entity is completed.

[0188] In aspect 46, in conjunction with aspect 38 or 39, the technology also includes configuring RLC entities.

[0189] In aspect 47, in conjunction with aspect 46, the technology also includes performing a handover operation to the target cell after configuring the RLC entity.

[0190] In aspect 48, in conjunction with aspect 47, the technology further includes re-establishing the RLC entity based on the completion of the handover operation to the target cell, and receiving the RLC control message after the RLC entity is re-established.

[0191] In aspect 49, in conjunction with aspect 48, RLC control messages include synchronous PDUs that include instructions.

[0192] In aspect 50, in conjunction with aspect 48 or 49, RLC control messages are included in RLC data PDUs that include the assigned RLC SN.

[0193] In the fifty-first aspect, in conjunction with one or more of aspects thirty-five to thirty-seven, one or more state variables are associated with a PDCP entity, and the control messages include PDCP control messages.

[0194] In aspect 52, in conjunction with one or more of aspects 35 to 37, the technology also includes receiving an RRC message indicating one or more initial values ​​for the set.

[0195] In aspect 53, in conjunction with aspect 51 or 52, the technology also includes configuring a PDCP entity, wherein configuring the PDCP entity includes setting one or more state variables to a set of one or more corresponding initial values.

[0196] In aspect 54, in conjunction with aspect 53, one or more corresponding initial values ​​in this group are based on a standard.

[0197] In aspect 55, in conjunction with aspect 53 or 54, at least one of the group of one or more corresponding initial values ​​is zero.

[0198] In aspect 56, in conjunction with one or more of aspects 53 to 55, the technology also includes initiating the establishment of a communication session after the configuration of the PDCP entity is completed.

[0199] In aspect 57, in conjunction with one or more of aspects 53 to 56, the technology also includes joining an ongoing multicast data session corresponding to the communication session.

[0200] In aspect 58, in conjunction with one or more of aspects 53 to 57, the PDCP control message is included in the PDCP PDU received at the next time after the configuration of the PDCP entity is completed.

[0201] In aspect 59, in conjunction with aspect 51, the technology also includes configuring a PDCP entity.

[0202] In the sixtieth aspect, in conjunction with the fifty-ninth aspect, the technology also includes performing a handover operation to the target cell after configuring the PDCP entity.

[0203] In the sixty-first aspect, in conjunction with the sixtieth aspect, the technology also includes re-establishing the PDCP entity based on the completion of the handover operation to the target cell, and receiving the PDCP control message after the PDCP entity is re-established.

[0204] In aspect sixty-two, in conjunction with aspect forty-nine, PDCP control messages include synchronous PDUs that include instructions.

[0205] In aspect sixty-three, in conjunction with one or more of aspects thirty-five to sixty-two, setting one or more state variables based on an instruction includes adjusting one or more state variables from one or more corresponding initial values ​​of that group to one or more corresponding values ​​of a first group based on an instruction.

[0206] In aspect sixty-four, in conjunction with one or more of aspects thirty-five to sixty-three, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0207] In aspect sixty-five, in conjunction with one or more of aspects thirty-five to sixty-four, the one or more state variables include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0208] In aspect sixty-six, in conjunction with one or more of aspects thirty-five to sixty-five, one or more state variables include window size and lower edge value or upper edge value.

[0209] In aspect sixty-seven, in conjunction with one or more of aspects thirty-five to sixty-six, the technique also includes setting one or more state variables based on an instruction.

[0210] In aspect sixty-eight, in conjunction with aspect sixty-seven, the technology further includes, after the setup and during a communication session, receiving one or more synchronous PDUs, each of the one or more received synchronous PDUs including a corresponding indication of a corresponding update to one or more state variables.

[0211] In aspect sixty-nine, in conjunction with aspect sixty-eight, the technology further includes updating the one or more state variables in response to receiving one of the one or more synchronous PDUs, based on a corresponding indication included in the received synchronous PDU.

[0212] In aspect 70, in conjunction with aspect 66 or 68, one or more synchronous PDUs include a plurality of synchronous PDUs that are periodically transmitted.

[0213] In some aspects, techniques for implementing the management of state variables may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In a seventy-first aspect, techniques for implementing the management of state variables may include generating a control message including an indication of one or more values ​​of one or more corresponding state variables associated with a communication window of a communication session, the one or more values ​​of the one or more state variables enabling synchronization of the communication window and differing from one or more initial values ​​of the one or more corresponding state variables; and sending the control message to the UE. In some examples, the techniques of aspect seventy-first may be implemented in a method or process. In some other examples, the techniques of aspect seventy-first may be implemented in a wireless communication device (such as a base station or a component of a base station). In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium having program code stored thereon, which, when executed by the processing unit, is configured to cause the wireless communication device to perform the operations described herein.

[0214] In aspect seventy-two, in conjunction with aspect seventy-one, the control messages include RLC control messages associated with the RLC entity of the UE.

[0215] In aspect seventy-three, in conjunction with aspect seventy-two, RLC entities include RLC AM entities or RLC UM entities.

[0216] In aspect seventy-four, in conjunction with aspects seventy-two or seventy-three, the technology also includes sending or receiving packets associated with the communication session after sending RLC control messages.

[0217] In aspect seventy-five, in conjunction with one or more of aspects seventy-two to seventy-four, the technology further includes determining whether the UE has joined a communication session or completed a handover operation, wherein the RLC control message is sent to the UE based on the determination that the UE has joined a communication session or completed a handover operation.

[0218] In aspect seventy-six, in conjunction with aspect seventy-five, RLC control messages are sent to the UE independently of the RLC SN associated with the communication session.

[0219] In aspect seventy-seven, in conjunction with one or more of aspects seventy-one to seventy-six, the technology further includes generating one or more synchronous PDUs, each of the one or more synchronous PDUs including a corresponding indication of a corresponding update to one or more state variables.

[0220] In aspect seventy-eight, in conjunction with aspect seventy-seven, the technology also includes initiating the transmission of or sending one or more synchronous PDUs.

[0221] In aspect 79, in conjunction with aspect 78, one or more synchronous PDUs include multiple synchronous PDUs that are periodically transmitted.

[0222] In aspect eighty, in conjunction with aspect seventy-eight or seventy-nine, each of one or more synchronous PDUs may be included in the corresponding RLC data PDU, which includes an RLC SN assigned based on the communication session.

[0223] In aspect eighty-one, in conjunction with aspect seventy-one, the control messages include PDCP control messages associated with the RLC entity of the UE.

[0224] In aspect 82, in conjunction with aspect 81, the technology also includes determining whether the UE has joined a communication session or completed a handover operation. In some implementations of aspect 82, based on the determination that the UE has joined a communication session or completed a handover operation, a PDCP control message is sent to the UE.

[0225] In aspect 83, in conjunction with aspect 81 or 82, the technology further includes generating one or more synchronous PDUs, each of the one or more synchronous PDUs including a corresponding indication of a corresponding update to one or more state variables.

[0226] In aspect 84, in conjunction with aspect 83, the technology also includes initiating the transmission of or sending one or more synchronous PDUs.

[0227] In aspect 85, in conjunction with aspect 84, one or more synchronous PDUs include a plurality of synchronous PDUs that are periodically transmitted, or each of one or more synchronous PDUs is included in a corresponding PDCP data PDU.

[0228] In aspect 86, in conjunction with aspect 84, based on the determination that the UE transitions from an asynchronous physical layer to a synchronous physical layer, the determination that the number of packet retransmissions is greater than or equal to a threshold, the determination of network load balancing or retransmission policy or PDCP level loss, at least one synchronous PDU is sent from one or more synchronous PDUs.

[0229] In aspect 87, in conjunction with one or more of aspects 71 to 86, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0230] In aspect 88, in conjunction with one or more of aspects 71 to 87, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0231] In aspect 89, in conjunction with one or more of aspects 71 to 88, the one or more state variables include the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0232] In some aspects, techniques for implementing the management of state variables may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In the 90th aspect, techniques for implementing the management of state variables may include initializing a set of state variables to a first set of initial values ​​associated with the synchronization of a communication window of a communication session; receiving a control message including an indication of a second set of current values ​​associated with a corresponding state variable in the set of state variables, at least one of the current values ​​being different from the corresponding initial value; setting the set of state variables to the second set of current values ​​to synchronize the communication window with the communication session; and receiving or transmitting packets associated with the communication session within the synchronized communication window. In some examples, the techniques in the 90th aspect may be implemented in a method or process. In some other examples, the techniques in the 90th aspect may be implemented in a wireless communication device, such as a UE or a component of a UE. In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium thereon storing program code that, when executed by a processing unit, is configured to cause a wireless communication device to perform the operations described herein.

[0233] In aspect ninety-one, in conjunction with aspect ninety, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0234] In aspect ninety-two, in conjunction with aspect ninety-one, communication sessions include multicast communication sessions.

[0235] In aspect ninety-three, in conjunction with aspect ninety, this set of state variables is associated with RLC entities, including RLC AM entities or RLC UM entities.

[0236] In aspect ninety-four, in conjunction with aspect ninety-three, the technology also includes configuring an RLC entity, wherein configuring the RLC entity includes setting the group of state variables to the corresponding initial values ​​of the first group.

[0237] In aspect ninety-five, in conjunction with aspect ninety-four, the first set of corresponding initial values ​​are based on the standard.

[0238] In aspect ninety-six, in conjunction with aspect ninety-four, at least one of the corresponding initial values ​​in the first group is zero.

[0239] In aspect ninety-seven, in conjunction with aspect ninety-four, the technology also includes initiating the establishment of a communication session after the configuration of the RLC entity is completed.

[0240] In aspect ninety-eight, in conjunction with aspect ninety-four, the technology also includes joining an ongoing multicast data session corresponding to the communication session.

[0241] In aspect ninety-nine, in conjunction with aspect ninety-four, the RLC control message is included in the RLC PDU received at the next time after the configuration of the RLC entity is completed.

[0242] In aspect one hundred, in conjunction with aspect ninety-three, the technology also includes configuring RLC entities.

[0243] In the 101st aspect, in conjunction with the 100th aspect, the technology also includes performing a handover operation to the target cell after configuring the RLC entity.

[0244] In a first aspect, in conjunction with the first aspect, the technology further includes re-establishing the RLC entity based on the completion of the handover operation to the target cell, and receiving the RLC control message after the RLC entity is re-established.

[0245] In aspect 103, in conjunction with aspect 102, the RLC control message includes a synchronous PDU that includes an indication.

[0246] In aspect 104, in conjunction with aspect 102, the RLC control message is included in the RLC data PDU, which includes the assigned RLC SN.

[0247] In aspect 105, in conjunction with aspect 90, setting the group of state variables based on an instruction includes adjusting the group of state variables from the corresponding initial values ​​of the first group to the current values ​​of the second group.

[0248] In aspect 106, in conjunction with aspect 90, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0249] In aspect 107, in conjunction with aspect 90, the set of state variables includes the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0250] In aspect 108, in conjunction with aspect 90, this set of state variables includes window size and lower edge value or upper edge value.

[0251] In aspect 109, in conjunction with aspect 90, the technology also includes setting group state variables based on instructions.

[0252] In aspect 110, in conjunction with aspect 109, the technology further includes receiving one or more synchronization PDUs after the setup and during the communication session, each of the one or more received synchronization PDUs including a corresponding indication of a corresponding update to the set of state variables.

[0253] In aspect 111, in conjunction with aspect 90, the technology further includes updating the set of state variables in response to receiving one of the one or more synchronous PDUs, based on a corresponding indication included in the received synchronous PDU.

[0254] In aspect 112, in conjunction with aspect 90, one or more synchronous PDUs include a plurality of synchronous PDUs that are periodically transmitted.

[0255] In aspect 113, in conjunction with aspect 90, the set of state variables is associated with the PDCP entity, and the control messages include PDCP control messages.

[0256] In aspect 114, in conjunction with aspect 90, the technology also includes receiving an RRC message indicating a first set of initial values.

[0257] In aspect 115, in conjunction with aspect 113, the technology further includes configuring a PDCP entity, wherein configuring the PDCP entity includes setting the group of state variables to the corresponding initial values ​​of the first group.

[0258] In aspect 116, in conjunction with aspect 115, the first set of corresponding initial values ​​are based on the standard.

[0259] In aspect 117, in conjunction with aspect 115, at least one of the corresponding initial values ​​in the first group is zero.

[0260] In aspect 118, in conjunction with aspect 115, the technology also includes initiating the establishment of a communication session after the configuration of the PDCP entity is completed.

[0261] In aspect 119, in conjunction with aspect 115, the technology also includes joining an ongoing multicast data session corresponding to the communication session.

[0262] In aspect 120, in conjunction with aspect 115, the PDCP control message is included in the PDCP PDU received at the next time after the configuration of the PDCP entity is completed.

[0263] In aspect 121, in conjunction with aspect 90, the technology also includes configuring a PDCP entity.

[0264] In aspect 122, in conjunction with aspect 121, the technology also includes performing a handover operation to the target cell after configuring the PDCP entity.

[0265] In the 123rd aspect, in conjunction with the 122nd aspect, the technology further includes re-establishing the PDCP entity based on the completion of the handover operation to the target cell, and receiving the PDCP control message after the PDCP entity is re-established.

[0266] In aspect 124, in conjunction with aspect 123, the PDCP control message includes a synchronous PDU that includes an indication.

[0267] In some aspects, techniques for implementing the management of state variables may include additional aspects, such as any single aspect or any combination of aspects described below, or in combination with one or more other processes or devices described elsewhere herein. In a first 125 aspect, techniques for implementing the management of state variables may include generating a control message including an indication of a set of values ​​of a set of state variables associated with a communication window of a communication session, the set of values ​​enabling synchronization of the communication window and differing from a set of initial values ​​of the set of state variables; and sending the control message to the UE. In some examples, the techniques of the first 125 aspect may be implemented in a method or process. In some other examples, the techniques of the first 125 aspect may be implemented in a wireless communication device, such as a base station or a component of a base station. In some examples, the wireless communication device may include at least one processing unit or system (which may include an application processor, modem, or other component) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium having program code stored thereon, the code being configured, when executed by the processing unit, to cause the wireless communication device to perform the operations described herein.

[0268] In aspect 126, in conjunction with aspect 125, the control message is associated with the UE's RLC entity.

[0269] In aspect 127, in conjunction with aspect 126, an RLC entity includes an RLC AM entity or an RLCUM entity.

[0270] In aspect 128, in conjunction with aspect 125, a communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

[0271] In aspect 129, in conjunction with aspect 125, the communication window includes a Tx window, an Rx window, or a combination thereof.

[0272] In aspect 130, in conjunction with aspect 125, the set of state variables includes the window size of the communication window, the lower edge value of the communication window, the upper edge value of the communication window, or a combination thereof.

[0273] In a 131st aspect, in conjunction with a 126th aspect, the technology further includes sending an RRC message indicating an initial value group, or, after sending a control message, sending or receiving packets associated with a communication session.

[0274] In the 132nd aspect, in conjunction with the 126th aspect, the technology further includes determining whether the UE has joined a communication session or completed a handover operation, wherein the control message is sent to the UE based on the determination that the UE has joined a communication session or completed a handover operation.

[0275] In aspect 133, in conjunction with aspect 132, RLC control messages are sent to the UE independently of the RLCSN associated with the communication session.

[0276] In aspect 134, in conjunction with aspect 125, the technology further includes generating one or more synchronous PDUs, each of the one or more synchronous PDUs including a corresponding indication of a corresponding update to the set of state variables.

[0277] In aspect 135, in conjunction with aspect 134, the technology further includes initiating the transmission of or sending one or more synchronous PDUs.

[0278] In aspect 136, in conjunction with aspect 135, one or more synchronous PDUs include multiple synchronous PDUs that are periodically transmitted.

[0279] In aspect 137, in conjunction with aspect 135, each of one or more synchronous PDUs may be included in the corresponding RLC data PDU, which includes an RLC SN assigned based on the communication session.

[0280] In aspect 138, in conjunction with aspect 125, control messages include PDCP control messages.

[0281] In the 139th aspect, in conjunction with the 138th aspect, the technology further includes determining whether the UE has joined a communication session or completed a handover operation, wherein the PDCP control message is sent to the UE based on the determination that the UE has joined a communication session or completed a handover operation.

[0282] In aspect 140, in conjunction with aspect 138, the technology further includes generating one or more synchronous PDUs, each of the one or more synchronous PDUs including a corresponding indication of a corresponding update to the set of state variables.

[0283] In one of the 141 aspects, the technology also includes initiating the transmission of one or more synchronous PDUs or sending the one or more synchronous PDUs.

[0284] In aspect 142, in conjunction with aspect 141, one or more synchronous PDUs include multiple synchronous PDUs that are periodically transmitted.

[0285] In aspect 143, in conjunction with aspect 141, each of one or more synchronous PDUs is included in the corresponding PDCP data PDU.

[0286] In aspect 144, in conjunction with aspect 141, based on the determination that the UE transitions from an asynchronous physical layer to a synchronous physical layer, the determination that the number of packet retransmissions is greater than or equal to a threshold, the determination of network load balancing or retransmission policy or PDCP level loss, at least one synchronous PDU among one or more synchronous PDUs is sent.

[0287] Those skilled in the art will understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the foregoing specification can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0288] The article about Figures 1 to 8 The components, functional blocks, and modules described include processors, electronic devices, hardware devices, electronic components, logic circuits, memory, software code, firmware code, and other examples, or any combination thereof. Furthermore, the features discussed herein can be implemented via dedicated processor circuitry, via executable instructions, or a combination thereof.

[0289] Those skilled in the art will also recognize that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally according to their functionality. Whether these functions are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the described functions in various ways for each specific application, but such implementation decisions should not be construed as causing a departure from the scope of this disclosure. Those skilled in the art will also readily recognize that the order or combination of components, methods, or interactions described herein are merely examples, and that components, methods, or interactions of various aspects of this disclosure can be combined or performed in ways other than those shown and described herein.

[0290] The various illustrative logics, logic blocks, modules, circuits, and algorithmic processes described herein can be implemented as electronic hardware, computer software, or a combination thereof. The interchangeability of hardware and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether these functions are implemented in hardware or software depends on the specific application and the design constraints imposed on the entire system.

[0291] Hardware and data processing apparatuses used to implement the various illustrative logics, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or performed by general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor or any conventional processor, controller, microcontroller, or state machine. In some implementations, the processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. In some implementations, specific processing and methods may be performed by circuitry specific to a given function.

[0292] In one or more aspects, the described functionality can be implemented in hardware, digital electronic circuits, computer software, firmware, including the structures disclosed in this specification and their structural equivalents, or any combination thereof. Implementation of the subject matter described in this specification can also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium, for execution by a data processing apparatus or for controlling the operation of a data processing apparatus.

[0293] If implemented in software, the functionality can be stored on a computer-readable medium or sent as one or more instructions or codes. Processing of the methods or algorithms disclosed herein can be implemented in a processor-executable software module that can reside on a computer-readable medium. Computer-readable media include computer storage media and communication media, with communication media including any medium that enables the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible to a computer. Similarly, any connection can be appropriately referred to as a computer-readable medium. Disks and optical discs as used herein include CDs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically copy data magnetically, while optical discs copy data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media. Furthermore, the operation of a method or algorithm may reside as one or any combination or set of code and / or instructions on a machine processor-readable medium and a computer-readable medium, which may be incorporated into a computer program product.

[0294] Various modifications to the implementations described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Therefore, the claims are not intended to limit the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles disclosed herein, and the novel features.

[0295] Furthermore, those skilled in the art will readily understand that the terms “upper” and “lower” are sometimes used to describe figures and indicate relative positions corresponding to the orientation of the figures on a correctly oriented page, and may not reflect the correct orientation of any implemented device.

[0296] Certain features described in this patent document in the context of a single implementation may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations. Furthermore, although features may be described above as functioning in a particular combination, or even originally claimed in this way, in some cases one or more features in the claimed combination may be removed from the combination, and the claimed combination may refer to a sub-combination or a variation of the sub-combination.

[0297] Similarly, although operations are depicted in a specific order in the figures, this should not be construed as requiring these operations to be performed in the specific order or sequence shown, or performing all of the shown operations, to obtain the desired result. Furthermore, the figures may schematically depict one or more example processes in the form of flowcharts. However, other operations not shown may be combined with the schematically shown example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the shown operations. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of the various system components in the above implementations should not be construed as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated into a single software product or packaged into multiple software products. In addition, some other implementations are within the scope of the appended claims. In some cases, the actions described in the claims may be performed in a different order and still achieve the desired result.

[0298] As used herein, including in the claims, when used in a list of two or more items, the term “or” means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a combination is described as containing components A, B, or C, the combination may contain A alone; B alone; C alone; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Furthermore, as used herein, including in the claims, “or” as used in a list of items beginning with “at least one of the following” indicates a disjunctive list, such that a list such as “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any combination thereof. The term “substantially” is defined as something that is substantially but not necessarily fully specified (and includes what is specified; for example, substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by one of ordinary skill in the art. In any disclosed implementation, the term “substantially” may be replaced by the specified “within [percentage]”, where the percentage includes 1%, 1%, 5%, or 10%.

[0299] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication performed by a user equipment (UE), the method comprising: Receive a control message generated at a network entity, the control message indicating the value of a state variable maintained by the network entity, the state variable being associated with a communication window of a communication session established with the network entity; Based on the control message, and considering the lack of synchronization between the UE and the network entity, the state variable is set from its previous value to the stated value; and Based on the value of the state variable, data associated with the communication session is received within the communication window.

2. The method for wireless communication executed by a user equipment (UE) according to claim 1, wherein the control message includes a Packet Data Convergence Protocol (DCP) control message.

3. The method for wireless communication performed by a user equipment (UE) according to claim 1, further comprising: The communication window is synchronized with the network entity by setting the state variable to the specified value.

4. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the state variables include a receive state variable RX_NEXT, a receive delivery state variable RX_DELIV, or both.

5. The method for wireless communication performed by a user equipment (UE) according to claim 1, further comprising: The state variable is initialized to the previous value selected from a plurality of possible previous values.

6. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the value is different from the prior value.

7. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

8. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the communication session includes a multicast communication session, the method further comprising: Join the communication session, wherein the control message is received in response to joining the communication session.

9. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the control message is included in a radio resource control (RRC) message.

10. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein the data includes Packet Data Convergence Protocol (PDCP) data.

11. The method for wireless communication performed by a user equipment (UE) according to claim 1, wherein receiving the control message includes receiving the control message as part of a handover operation between a second network entity and the network entity.

12. An apparatus for wireless communication, the apparatus comprising: A processing system comprising one or more processors and one or more memories coupled to the one or more processors, the processing system being configured to: Receive a control message generated at a network entity, the control message indicating the value of a state variable maintained by the network entity, the state variable being associated with a communication window of a communication session established with the network entity; Based on the control message, and due to the lack of synchronization between the device and the network entity, the state variable is set from its previous value to the current value; and Based on the value of the state variable, data associated with the communication session is received within the communication window.

13. The apparatus for wireless communication according to claim 12, wherein the control message includes a Packet Data Convergence Protocol (PDCP) control message.

14. The apparatus for wireless communication according to claim 12, wherein the processing system is further configured to: The communication window is synchronized with the network entity by setting the state variable to the specified value.

15. The apparatus for wireless communication according to claim 12, wherein the state variable includes a receive state variable RX_NEXT, a receive transfer state variable RX_DELIV, or both.

16. The apparatus for wireless communication according to claim 12, wherein the processing system is further configured to: The state variable is initialized to the previous value selected from a plurality of possible previous values.

17. The apparatus for wireless communication according to claim 12, wherein the value is different from the previous value.

18. The apparatus for wireless communication according to claim 12, wherein the communication session includes a unicast communication session, a multicast communication session, or a broadcast communication session.

19. The apparatus for wireless communication according to claim 12, wherein the communication session includes a multicast communication session, and wherein the processing system is further configured to: Joining the communication session, wherein the processing system is configured to receive the control message in response to joining the communication session.

20. The apparatus for wireless communication according to claim 12, wherein the control message is included in a Radio Resource Control (RRC) message.

21. The apparatus for wireless communication according to claim 12, wherein the data includes Packet Data Convergence Protocol (PDCP) data.

22. The apparatus for wireless communication according to claim 12, wherein, in order to receive the control message, the processing system is configured to: The control message is received as part of the handover operation between the second network entity and the network entity.

23. A method for wireless communication performed by a network entity, the method comprising: A control message is generated, the control message indicating the value of a state variable maintained by the network entity, the state variable being associated with a communication window of a communication session established with a user equipment (UE), wherein the control message indicating the value is generated based on a lack of synchronization between the UE and the network entity; as well as Send the control message to the UE; as well as Based on the value of the state variable, data associated with the communication session is sent within the communication window.

24. The method for wireless communication performed by a network entity according to claim 23, wherein the control message includes a Packet Data Convergence Protocol (PDCP) control message, and wherein the control message is included in a Radio Resource Control (RRC) message.

25. The method for wireless communication performed by a network entity according to claim 23, wherein the value is different from a previous value of a corresponding instance of the state variable stored in the memory of the UE.

26. The method for wireless communication performed by a network entity according to claim 23, wherein sending the control message to the UE includes sending the control message to the UE in response to joining a communication session with the UE.

27. An apparatus for wireless communication, the apparatus comprising: A processing system comprising one or more processors and one or more memories coupled to the one or more processors, the processing system being configured to: A control message is generated, the control message indicating the value of a state variable maintained by the one or more memories, the state variable being associated with a communication window of a communication session established with a user equipment (UE), wherein the control message indicating the value is generated based on a lack of synchronization between the UE and the device; Send the control message to the UE; and Based on the value of the state variable, data associated with the communication session is sent to the UE within the communication window.

28. The apparatus for wireless communication according to claim 27, wherein the control message includes a Packet Data Convergence Protocol (PDCP) control message, and wherein the control message is included in a Radio Resource Control (RRC) message.

29. The apparatus for wireless communication according to claim 27, wherein the value is different from a previous value of a corresponding instance of the state variable stored in one or more memories of the UE.

30. The apparatus for wireless communication according to claim 27, wherein, in order to send the control message, the processing system is configured to send the control message to the UE in response to joining the communication session with the UE.

31. A computer-readable medium having program code recorded thereon, which, when executed by one or more processors of a user equipment (UE), causes the one or more processors to perform the method according to any one of claims 1-11.

32. A computer-readable medium having program code recorded thereon, which, when executed by one or more processors of a network entity, causes the one or more processors to perform the method according to any one of claims 23-26.

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