CN116420400A - Method, apparatus and computer program - Google Patents

Abstract

There is provided an apparatus comprising means for at a terminal device: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting data units to a network node; determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer; configuring the logical channel with the modified set of physical channel parameters based on the determining; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

Description

Method, apparatus and computer program

Technical Field

The present application relates to a method, apparatus, system and computer program and in particular, but not exclusively, to dynamic modification of LCH mapping limits upon expiration of a cg retransmission timer.

Background

A communication system may be considered a facility for effectuating a communication session between two or more entities, such as a user terminal, a base station, and/or other node, by providing carriers between the various entities involved in a communication path. For example, the communication system may be provided by means of a communication network and one or more compatible communication devices (also called stations or user devices) and/or application servers. The communication session may include, for example, communications for carrying data for the communication, such as voice, video, electronic mail (email), text messages, multimedia, content data, time Sensitive Network (TSN) streams, and/or data in industrial applications, such as critical system messages between actuators and controllers, critical sensor data (such as measurements, video feeds, etc.) towards the control system, and so forth. Non-limiting examples of services provided include two-way or multi-way calls, data communications, or multimedia services, and access to data network systems such as the internet.

In a wireless communication system, at least a portion of a communication session occurs over a wireless link, for example, between at least two stations or between at least one station and at least one application server (e.g., for video). Examples of wireless systems include Public Land Mobile Networks (PLMNs) operating based on 3GPP radio standards such as E-UTRA, new air interfaces, satellite-based communication systems, and different wireless local area networks such as Wireless Local Area Networks (WLANs). A wireless system may be generally divided into cells and is therefore generally referred to as a cellular system.

The user may access the communication system by means of a suitable communication device or terminal. The user's communication equipment may be referred to as User Equipment (UE) or user equipment. The communication device is provided with suitable signal receiving and transmitting means for enabling communication, e.g. access to a communication network or communication directly with other users. A communication device may access one or more carriers provided by a network, such as a base station of a cell, and transmit and/or receive communications on the one or more carriers. In Carrier Aggregation (CA), two or more carriers are combined into one channel. In Dual Connectivity (DC), two carriers from different sites are combined, that is, a user equipment may be dual (or multiple) connected to two (or more) sites.

Communication systems and related devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which should be used for the connection are also typically defined. One example of a communication system is UTRAN (3G radio). Other examples of communication systems are the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) based on the E-UTRAN radio access technology, and the so-called 5G system (5 GS), which comprises a 5G or Next Generation Core (NGC) and a 5G access network based on the new air interface (NR) radio access technology. The 5GS including NR is being standardized by the third generation partnership project (3 GPP).

Disclosure of Invention

In a first aspect, there is provided an apparatus comprising means for performing at a terminal device: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting the data unit to the network node; determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer; configuring the logical channel with the modified set of logical channel parameters based on the determining; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

The set of logical channel parameters and the set of modified logical channel parameters may include at least one of at least one LCH mapping limit, LCH priority, prioritized bit rate, bucket size duration, and channel access priority class.

The at least one LCH mapping limit may indicate a list of allowed configuration grants.

The at least one LCH mapping restriction may indicate a list of allowed serving cells.

The apparatus may include means for receiving at least one configuration message from a network node, the configuration message indicating at least one of a set of logical channel parameters and a set of modified logical channel parameters.

The first timer may be a cg retransmission timer.

The state of the first timer may include expiration of the first timer.

The apparatus may include means for reverting to a configuration of a set of logical channel parameters for a logical channel based on at least one condition.

The at least one condition may include at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

The apparatus may include means for receiving an indication of at least one condition from a network node.

In a second aspect, a method is provided, the method comprising, at a terminal device: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting data units to a network node; determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer; configuring the logical channel with the modified set of logical channel parameters based on the determining; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

The set of logical channel parameters and the set of modified logical channel parameters may include at least one of at least one LCH mapping limit, LCH priority, prioritized bit rate, bucket size duration, and channel access priority class.

The at least one LCH mapping limit may indicate a list of allowed configuration grants.

The at least one LCH mapping restriction may indicate a list of allowed serving cells.

The method may include receiving at least one configuration message from a network node, the configuration message indicating at least one of a set of logical channel parameters and a set of modified logical channel parameters.

The first timer may be a cg retransmission timer.

The state of the first timer may include expiration of the first timer.

The method may include reverting to a configuration of a set of logical channel parameters for the logical channel based on at least one condition.

The at least one condition may include at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

The method may comprise receiving an indication of at least one condition from a network node.

In a third aspect, there is provided an apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to, at a terminal device: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting the data unit to the network node; determining to configure the logical channel with a modified set of logical channel parameters based on the state of the first timer; configuring the logical channel based on the determined set of utilizing modified logical channel parameters; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

The set of logical channel parameters and the set of modified logical channel parameters may include at least one of at least one LCH mapping limit, LCH priority, prioritized bit rate, bucket size duration, and channel access priority class.

The at least one LCH mapping limit may indicate a list of allowed configuration grants.

The at least one LCH mapping restriction may indicate a list of allowed serving cells.

The apparatus may be configured to receive at least one configuration message from a network node, the configuration message indicating at least one of a set of logical channel parameters and a set of modified logical channel parameters.

The first timer may be a cg retransmission timer.

The state of the first timer may include expiration of the first timer.

The apparatus may be configured to revert to a configuration of a set of logical channel parameters for the logical channel based on at least one condition.

The at least one condition may include at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

The apparatus may be configured to receive an indication of at least one condition from a network node.

In a fourth aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at a terminal device at least the following: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting the data unit to the network node; determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer; configuring the logical channel with the modified set of logical channel parameters based on the determining; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

The modified set of logical channel parameters may include at least one of at least one LCH mapping limit, LCH priority, prioritized bit rate, bucket size duration, and channel access priority class.

The at least one LCH mapping limit may indicate a list of allowed configuration grants.

The at least one LCH mapping restriction may indicate a list of allowed serving cells.

The apparatus may be caused to perform receiving at least one configuration message from a network node, the configuration message indicating at least one of a set of logical channel parameters and a set of modified logical channel parameters.

The first timer may be a cg retransmission timer.

The state of the first timer may include expiration of the first timer.

The apparatus may be caused to perform a restoration to a configuration of a set of logical channel parameters for the logical channel based on the at least one condition.

The at least one condition may include at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

The apparatus may be caused to perform receiving an indication of at least one condition from a network node.

In a fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the second aspect.

In the foregoing, many different embodiments have been described. It should be appreciated that further embodiments may be provided by combinations of any two or more of the above embodiments.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of an example 5G communication system;

FIG. 2 shows a schematic diagram of an example mobile communication device;

FIG. 3 shows a schematic diagram of an example control device;

FIG. 4 shows a flow chart of a method according to an example embodiment;

fig. 5 shows a signaling flow according to an example embodiment;

FIG. 6 shows a logic flow diagram at a terminal according to an example embodiment;

fig. 7 shows a schematic diagram of a first configuration authority CG1 and a second configuration authority CG 2.

Detailed Description

Before explaining examples in detail, certain general principles of wireless communication systems and mobile communication devices will be briefly explained with reference to fig. 1 to 3 to assist in understanding the techniques behind the examples.

An example of a suitable communication system is the 5G system (5 GS). The network architecture in 5GS may be similar to that of LTE-advanced. The base station of the NR system may be referred to as a next generation node B (gNB). Changes to the network architecture may depend on the need to support various radio technologies and finer QoS support, as well as on-demand requirements for some QoE for supporting users, e.g., qoS levels. Furthermore, network aware services and applications, as well as service and application aware networks, may bring about changes to the architecture. These are related to Information Centric Networking (ICN) and user centric content delivery networking (UC-CDN) approaches. NR can use multiple-input multiple-output (MIMO) antennas with many more base stations or nodes than LTE (so-called small cell concept) including macro sites operating in cooperation with smaller stations, and possibly also use various radio technologies to achieve better coverage and enhanced data rates.

The 5G network may utilize Network Function Virtualization (NFV), a network architecture concept, which proposes to virtualize network node functions as "building blocks" or entities that are operatively connected or linked together to provide services. A Virtualized Network Function (VNF) may comprise one or more virtual machines that run computer program code using standard or generic type servers instead of custom hardware. Cloud computing or data storage may also be utilized. In radio communications, this may mean performing node operations at least in part in a server, host, or node operatively coupled to the remote radio head. Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be appreciated that the labor profile between core network operation and base station operation may be different from that of LTE, or even absent.

Fig. 1 shows a schematic diagram of a 5G system (5 GS) 100. The 5GS may include a User Equipment (UE) 102 (which may also be referred to as a communication device or terminal), a 5G radio access network (5 GRAN) 104, a 5G core network (5 GCN) 106, one or more Application Functions (AFs) 108, and one or more Data Networks (DNs) 110.

An example 5G Core Network (CN) includes functional entities. The 5gcn 106 may include one or more access and mobility management functions (AMFs) 112, one or more Session Management Functions (SMFs) 114, an authentication server function (AUSF) 116, a Unified Data Management (UDM) 118, one or more User Plane Functions (UPFs) 120, a Unified Data Repository (UDRs) 122, and/or a Network Exposure Function (NEF) 124. The UPF is controlled by an SMF (session management function) that receives policies from the PCF (policy control function).

The CN is connected to the terminal device via a Radio Access Network (RAN). The 5GRAN may include one or more GNodeB (GNB) distributed cell functions connected to one or more GNodeB (GNDB) centralized cell functions. The RAN may include one or more access nodes.

The UPF (user plane function), whose role is called PSA (PDU session anchor), may be responsible for forwarding frames back and forth between DN (data network) and tunnels established over 5G to UEs exchanging traffic with the DN.

A possible terminal device will now be described in more detail with reference to fig. 2, fig. 2 showing a schematic partial cross-sectional view of a communication device 200. Such communication devices are often referred to as User Equipment (UE). A suitable communication device may be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include a Mobile Station (MS) or mobile device, such as a mobile phone or so-called "smart phone", a computer provided with a wireless interface card or other wireless interface facility (e.g., a USB dongle), a Personal Data Assistant (PDA), or a tablet computer provided with wireless communication capabilities, or any combination of these or similar devices. For example, a communication device may provide data communication for carrying communications such as voice, electronic mail (email), text messages, multimedia, and the like. Thus, many services may be provided to a user via the user's communication device. Non-limiting examples of such services include two-way or multi-way calls, data communications or multimedia services, or simply accessing a data communications network system such as the internet. Broadcast or multicast data may also be provided to the user. Non-limiting examples of content include downloads, television and radio programming, video, advertising, various alerts, and other information.

The device is typically provided with at least one data processing entity 201, at least one memory 202 and possibly other components 203 for software and hardware assistance in performing the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. The data processing, storage and other associated control means may be provided on a suitable circuit board and/or in a chipset. This feature is indicated by reference numeral 204. The user may control the operation of the mobile device by means of a suitable user interface such as a keypad 205, voice commands, touch sensitive screen or touchpad, combinations thereof, and the like. A display 208, speakers, and microphone may also be provided. In addition, the mobile communication device may include suitable connectors (wired or wireless) to other devices and/or for connecting external accessories thereto, such as a hands-free device.

The apparatus 200 may receive signals over the air or radio interface 207 via suitable means for receiving and may transmit signals via suitable means for transmitting radio signals. In fig. 2, the transceiver device is schematically represented by block 206. The transceiver device 206 may be provided, for example, by means of a radio and an associated antenna arrangement. The antenna arrangement may be arranged inside or outside the mobile device.

Fig. 3 shows an example embodiment of a control apparatus for a communication system, e.g. for a station, such as a RAN node, e.g. a base station, eNB or gNB, a relay node or core network node, such as an MME or S-GW or P-GW, or a core network function, such as an AMF/SMF, or a server or host, coupled to and/or controlling an access system. The method may be implanted in a single control unit or span more than one control unit. The control means may be integrated with or external to a node or module of the core network or RAN. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device may be another network element, such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such control means as well as control means provided in a radio network controller. The control means 300 may be arranged to provide control of the communication in the service area of the system. The control device 300 comprises at least one memory 301, at least one data processing unit 302, 303 and an input/output interface 304. Via the interface, the control device may be coupled to a receiver and a transmitter of the base station. The receiver and/or transmitter may be implemented as a radio front-end or a remote radio head.

In 3GPP Rel-17, it is expected that the Internet of things (IIoT)/Ultra Reliable Low Latency Communication (URLLC) should be supported in unlicensed new air interface bands (NR-U), with emphasis on enhancements related to configuration grants. Furthermore, 3GPP should address the new requirements for lifetime. Some contexts for these aspects are provided below.

In 3GPP Rel-17, there are ongoing work items for IIoT/URLLC enhancements. The following targets are listed in the approved WID RP-201310:

2. uplink enhancements for URLLC in unlicensed controlled environments [ RAN1, RAN2]:

a. specifying support for UE-initiated Channel Occupancy Time (COT) for frame-based devices (FBEs) with minimal specification workload

b. Coordinating UL configuration grant enhancements in NR-U and URLLC introduced in Rel-16 to accommodate unlicensed spectrum

5. RAN enhancements based on new quality of service (QoS) related parameters (if any) determined in SA2, e.g., time-to-live, burst extension. RAN2, RAN3

IIoT's Time Sensitive Communications (TSC) have some unique requirements and characteristics compared to traditional cellular communications where the UE is primarily a handset. For example, traffic patterns of TSCs are typically periodic with a fixed burst size, which allows the scheduler to determine resource allocation in a more intelligent manner. It has been agreed in Rel-16 that the gNB may determine certain information related to traffic flows based on TSC assistance information (TSCAI) from the core network, so that the gNB may allocate configuration scheduling resources (e.g., semi-persistent scheduling (SPS) and Configuration Grant (CG)) for appropriate parameters such as periodicity and transport block size to meet the needs of the TSC flows. For the uplink, configuration Grant (CG) is especially important for TSC traffic due to its periodicity.

Industrial applications may have a requirement called time-to-live, meaning a time interval during which the application is still operational without receiving the intended message. More formally, the time-to-live is defined in TS22.104 as the time that an application consuming a communication service can continue without an expected message.

The time-to-live indicates to the communication service the time that can be recovered from the failure. The time-to-live may be expressed as a time period or, for example, for a recurring service, as a maximum number of consecutive incorrectly received or lost messages. Since time-to-live has now been approved by SA2 as a new QoS requirement, how the RAN should be enhanced to achieve time-to-live protection (i.e. avoid continuous message loss) is a key topic in Rel-17.

NR-U has further limitations compared to conventional operation in the licensed band due to potential Listen Before Talk (LBT) failure. Thus, mechanisms have been introduced for NR-U to facilitate its operation. In particular, for Configuration Grant (CG), a UE may perform autonomous retransmission of pending Media Access Control (MAC) Protocol Data Units (PDUs). This is controlled by a CG retransmission timer that is started when CG-PUSCH is transmitted. If the UE does not receive any Downlink Feedback Information (DFI) from the gNB indicating the status of MAC PDUs pending in different hybrid automatic repeat request (HARQ) processes before the timer expires, the UE may assume that the CG physical uplink shared channel (CG-PUSCH) was not successfully transmitted and then perform autonomous retransmission on subsequent CG resources.

In 5G NR, there is a Logical Channel (LCH) mapping restriction that forces the MAC layer (of the UE) to map data from LCH to resources that are only suitable for certain characteristics. This allows data from DRBs to be transmitted on the appropriate radio resources according to their QoS requirements. For example, multiple concurrent active CG per bandwidth portion (BWP) may be supported in Rel-16, and a new LCH mapping limit, referred to as a list of allowed CGs, may be configured for LCHs such that data from LCHs can only be transferred by CG resources indicated on the list. More details on this feature can be found in section 5.4.3.1.2 of TS 38.321.

The IIoT/URLLC enhanced Rel-17 WI considers operations in NR-U, as well as RAN enhancement to meet time-to-live requirements. In this context, it would be useful to enhance the NR-U mechanism to support time-to-live requirements (i.e., reduce the probability of consecutive message loss).

The following concepts have been developed as RAN functions to meet the time-to-live requirements:

two methods for time-to-live have been proposed: (1) Adaptive LCH mapping restriction rules via, for example, LCHs that alternate over time according to sequence numbers of packets, and (2) configuration scheduling (e.g., CG/SPS) that includes two types of resource allocation.

Another proposal is to implicitly activate Packet Data Convergence Protocol (PDCP) duplication of Dedicated Radio Bearers (DRBs) based on negative HARQ feedback. For example, if the UE receives a non-handover New Data Indicator (NDI) in an uplink grant, the UE will automatically copy the next packet at a higher layer to prevent consecutive errors.

The time-to-live requirements for unlicensed band operation have been considered. One proposed method is to periodically adapt the Channel Access Priority Class (CAPC) that configures grants to ensure that every nth packet can access an unlicensed channel with a low likelihood of LBT failure. The transmission reliability problem has not been solved.

Fig. 4 shows a flow chart of a method according to an example embodiment. The method may be performed at a terminal device.

In a first step S1, the method comprises transmitting a data unit to the network node, the data unit conveying data from the LCH configured with the set of logical channel parameters.

In a second step S2, the method comprises starting a first timer when transmitting data units to the network node.

In a third step S3, the method comprises configuring the LCH with the modified set of logical channel parameters based on the state of the first timer.

In a fourth step S4, the method comprises configuring the LCH with the modified set of logical channel parameters based on the determination.

In a fifth step S5, the method transmits a data unit to the network node, the data unit conveying data from a logical channel configured with a set of modified logical channel parameters.

The modified set of logical channel parameters may provide more reliable resources for the logical channel.

The set of logical channel parameters and the set of modified logical channel parameters may include at least one LCH mapping limit. The at least one LCH mapping limit may indicate a list of allowed configuration grants.

This set of logical channel parameters may be referred to as a default set of logical channel parameters. The modified set of logical channel parameters may be referred to as an adaptive set of logical channel parameters. The set of logical channel parameters may be Logical Channel Prioritization (LCP) settings.

The state of the first timer may include expiration of the first timer. The first timer may be a cg transmit timer.

Alternatively or additionally, the method may include determining to configure the logical channel with the modified set of logical channel parameters based on receiving an indication from the network node that the transmission was not successfully received. The indication may include a DFI or retransmission grant.

The data unit may include a Transport Block (TB).

The method may provide a MAC mechanism for dynamically modifying LCH mapping limits configured for an LCH according to a state of a cg retransmission timer associated with data from the PUSCH transmission for the LCH. Alternatively or additionally, if the UE receives a signal indicating that the gNB did not successfully receive a previous transmission related to the LCH (e.g., DFI or retransmission grant), the UE may dynamically modify the LCH mapping limits configured for the LCH. This may help to meet the time-to-live requirements of IIoT/TSC applications in NR-U.

For example, when the CG retransmission timer expires (i.e., the UE does not receive any DFI while the timer is running), the UE may assume that the PUSCH was not successfully transmitted and (at least temporarily) change the LCH mapping limit for at least one LCH configuration related to the transmitted PUSCH, e.g., such that the grant of a particular configuration is made the only resource on the CG list allowed in the LCH mapping limit for the LCH. This forces the UE to transmit subsequent data from the same LCH on more reliable radio resources, thereby reducing the probability of consecutive transmission errors.

The method may include receiving at least one configuration message from a network node, the configuration message indicating at least one of a set of logical channel parameters and a set of modified logical channel parameters. For example, at least one configuration message may be provided from the gNB to the UE. The at least one configuration message may include a default LCH mapping limit for the at least one LCH and a modified LCH mapping constraint for the at least one LCH based on a state of the cg retransmission timer (e.g., upon expiration of the timer). In one example, the default LCH mapping limits do not impose any limits (i.e., data from the LCH may be mapped to any resources), while the modified LCH mapping constraints impose certain limits on how to map data from the LCH. That is, the LCH mapping restriction is only applied when the timer expires, otherwise the LCH mapping restriction is released.

If the logical channel has an associated time-to-live requirement, a network node (e.g., a gNB) may determine a modified set of logical channel parameters that provide the logical channel to the UE. The UE may determine whether the logical channel has a time-to-live requirement based on whether the logical channel is configured with both the set of logical channel parameters and the modified set of logical channel parameters (and thus whether it should retransmit the data unit using the modified set of logical channel parameters)

The UE may modify the LCH mapping limits (from default settings to modified settings) of the at least one LCH based on the state of the cg retransmission timer. The UE may also restore the LCH mapping limits from the adapted settings back to default settings of the at least one LCH.

The method may include reverting to a configuration of a set of logical channel parameters for the LCH based on at least one condition. The at least one condition may include at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

The second timer may be referred to as an LCP adapt timer.

The control signal from the network node may comprise a MAC CE or DCI. For example, in some embodiments, upon receiving a control signal (e.g., MAC CE or DCI) from the gNB, the UE may fall back to a default set of logical channel parameters. Alternatively, once at least one TB is generated using the adapted LCH mapping limits, or when the UE has acknowledged that the TB was successfully transmitted and/or received, the UE may fall back to a default set of logical channel parameters.

The method may include receiving an indication of the condition from a network node. For example, the condition for the UE to fall back to the default set of logical channel parameters (e.g., the value of the LCP adaptation timer) may be preconfigured by the gNB. The at least one configuration message may include instructions regarding when to fall back to a default set of logical channel parameters for the at least one LCH.

Fig. 5 shows a signaling flow according to an example embodiment. Initially, the gNB configures the UE with default LCH mapping limits and adapted LCH mapping constraints for LCHs (e.g., via Radio Resource Control (RRC)). CG-PUSCH associated with the LCH is transmitted based on the default LCH mapping limit, and thus the CG retransmission timer is started. When the cg retransmission timer expires (e.g., because no Downlink Feedback Information (DFI) is received at the UE), the UE changes the LCH mapping limits of the LCH.

A new CG-PUSCH is transmitted based on the adapted LCH mapping restrictions.

When the UE changes the LCH mapping limit for the LCH, it may further start another timer, e.g., called an LCP adaptation timer. Upon expiration of the LCP adaptation timer, the UE alters the LCH mapping limits for the LCH back to default settings.

Fig. 6 shows UE logic for determining whether a UE should change LCH mapping limits for LCH upon expiration of a cg retransmission timer, according to an example embodiment. When the DFI is not received and the cg retransmission timer expires, the UE may check whether any LCH mapped to the TB whose transmission triggered the timer has a time-to-live requirement. This may be implied based on whether the LCH is configured with both default and adapted LCH mapping restrictions (typically, if the traffic corresponding to that LCH has time-to-live requirements, the gNB should only configure LCHs with both settings). If so, the UE may change the LCH mapping limit setting. Otherwise, it will work as usual, i.e. only perform autonomous retransmission of the TB.

Fig. 7 shows an example embodiment in which a UE has traffic flows with time-to-live requirements. Traffic flows are mapped to DRBs. The gNB is configured with at least two Cgs, namely CG1 and CG2, in BWP.

CG1 is configured to have a reliability target that meets QoS requirements (e.g., packet Error Rate (PER)) of traffic communicated by the DRB.

CG2 is configured to have higher reliability targets than CG1, e.g., lower Modulation and Coding Schemes (MCSs) and/or more repetitions at each CG occasion.

In the MAC layer, the LCH corresponding to the DRB is configured with a default LCH mapping restriction, with CG1 on the allowed CG list. This means that by default, data from the LCH may be mapped to radio resources associated with CG 1.

In addition to this default LCH mapping limit setting, the gNB also configures an adaptation setting in which only CG2 is on the allowed CG list (i.e., CG1 is removed from the list in this adaptation setting). When the associated cg retransmission timer expires (i.e., no DFI has been received), the UE should switch to this adaptation setting for this LCH.

When transmitting PUSCH on CG1 triggering CG retransmission timer to start according to the current specification, the UE observes if it receives DFI from the gNB when the timer runs. If the UE does not receive the DFI and the timer expires, the UE further checks if the pending TB contains any data from the LCH configured with the adaptation settings (meaning that the data from the LCH has a time-to-live requirement). If so, the UE should switch the LCH mapping restriction of the LCH from the default setting to the adaptation setting.

As the LCH mapping limits switch, the upcoming data from the LCH should follow the new mapping limit rules to generate a new TB for the new transmission. In this example, subsequent data from this LCH should only map to CG2 (no longer to CG 1) until it switches back to the default setting again (e.g., upon expiration of the LCP adapt timer).

In an alternative embodiment, the at least one LCH mapping restriction may indicate a list of allowed serving cells. For example, the proposed scheme may be applied to LCH mapping restrictions related to allowed serving cells.

For example, where the UE has both licensed and unlicensed bands, it may have default LCH mapping restrictions for LCHs with allowed serving cells in both licensed and unlicensed bands, and modified LCH mapping restrictions for allowed serving cells only in licensed bands.

Thus, in this example embodiment, upon, for example, the first expiration of a cg retransmission timer or receipt of an indication from a network node that transmission was unsuccessful, the UE is caused to transmit subsequent data from the LCH using only the resources in the licensed band to ensure that the next packet is not unsuccessfully transmitted due to, for example, LBT failure occurring in the unlicensed band, and thereby reduce the probability of continuous errors.

The method may be extended to the adaptation of other parameters in LCP settings including LCH priority, prioritized Bit Rate (PBR), bucket Size Duration (BSD), and Channel Access Priority Class (CAPC). That is, in alternative example embodiments, the set of logical channel parameter settings may include LCH priority, PBR, BSD, and cap.

In some embodiments, only the default set of logical channel parameters is configured by the network node, without requiring additional configuration of the modified set of logical channel parameters. In this case, the set of modified logical channel parameters may be known settings (e.g., fixed in the specification), so no explicit configuration is required. Alternatively, or in addition, the default set of logical channel parameters may be known settings (e.g., fixed in the specification) and thus do not require explicit configuration.

In addition to changing the set of logical channel parameters, other types of adaptations may be made upon expiration of the cg retransmission timer, such as activation of a CAPC upgrade for the LCH or PDCP copying of the DRB associated with the LCH.

An advantage of this approach is that when transmitting a data unit of traffic with time-to-live requirements in the NR unlicensed spectrum, the UE may be forced to transmit subsequent data in a more reliable manner if it detects that the data unit may not be successfully received by the gNB (i.e. the cg retransmission timer expires). Thus, the probability of continuous transmission failure that may lead to a time-to-live violation may be reduced.

The method may be implemented in a user equipment as described with reference to fig. 2.

An apparatus may include means for, at a terminal device, performing: transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters; starting a first timer when transmitting data units to a network node; determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer; configuring the logical channel with the modified set of logical channel parameters based on the determining; and transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

It should be understood that these means may comprise or be coupled to other units or modules etc., such as radio parts or radio heads for transmitting and/or receiving. Although the apparatus has been described as one entity, the different modules and memories may be implemented in one or more physical or logical entities.

Note that although the embodiments have been described in terms of LTE and 5G NR, similar principles may be applied to other networks and communication systems. Thus, although certain embodiments are described above by way of example with reference to certain example architectures for wireless networks, technologies, and standards, embodiments may be applied to any other suitable form of communication system than those shown and described herein.

It is also noted herein that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

In general, the various example embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Embodiments of the invention may be implemented by computer software executable by a data processor of a mobile device, for example in a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs, also referred to as program products, including software routines, applets, and/or macros, can be stored in any device-readable data storage medium and they include program instructions that perform particular tasks. The computer program product may include one or more computer-executable components configured to perform embodiments when the program is run. The one or more computer-executable components may be at least one software code or portion thereof.

Further in this regard, it should be noted that any blocks of the logic flows as shown in the figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or blocks of memory implemented within a processor, magnetic media such as hard or floppy disks, and optical media such as DVDs and their data variants CDs. The physical medium is a non-transitory medium.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. As non-limiting examples, the data processor may be of any type suitable to the local technical environment, and may include one or more of a general purpose computer, a special purpose computer, a microprocessor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an FPGA, a gate level circuit, and a processor based on a multi-core processor architecture.

Example embodiments of the invention may be practiced in various components such as integrated circuit modules. Overall, the design of integrated circuits is a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples a full and informative description of exemplary embodiments of the invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims. Indeed, there are further embodiments that include a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims (13)

1. An apparatus comprising means for, at a terminal device:

transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters;

starting a first timer when transmitting the data unit to the network node;

determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer;

based on the determination, configuring the logical channel with a modified set of logical channel parameters; and

Transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

2. The apparatus of claim 1, comprising means for receiving at least one configuration message from the network node indicating at least one of the set of logical channel parameters and the set of modified logical channel parameters.

3. The apparatus of claim 1 or claim 2, wherein the set of logical channel parameters and the set of modified logical channel parameters comprise at least one of LCH mapping limits, LCH priorities, prioritized bit rates, bucket size durations, and channel access priorities.

4. A device according to claim 3, wherein the at least one LCH mapping limit indicates a list of allowed configuration grants.

5. The apparatus of claim 3, wherein the at least one LCH mapping restriction indicates a list of allowed serving cells.

6. The apparatus of any of claims 1 to 5, wherein the first timer is a cg retransmission timer.

7. The device of any of claims 1-6, wherein the status of the first timer comprises expiration of the first timer.

8. The apparatus according to any of claims 1 to 7, comprising means for reverting to a configuration of the set of logical channel parameters for the logical channel based on at least one condition.

9. The apparatus of claim 8, wherein the at least one condition comprises at least one of expiration of a second timer, receipt of a control signal from the network node, confirmation that the data unit has been successfully transmitted and received, and generation of the data unit.

10. The apparatus of claim 8 or 9, comprising receiving an indication of the at least one condition from the network node.

11. A method comprising, at a terminal device:

transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters;

starting a first timer when transmitting the data unit to the network node;

determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer;

configuring the logical channel with the modified set of logical channel parameters based on the determining; and

Transmitting a data unit to the network node, the data unit conveying data from the logical channel configured with the modified set of logical channel parameters.

12. An apparatus, comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters;

starting a first timer when transmitting the data unit to the network node;

determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer;

based on the determination, configuring the logical channel with the modified set of logical channel parameters; and

transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

13. A computer readable medium comprising program instructions for causing an apparatus to perform at a terminal device at least the following:

Transmitting a data unit to a network node, the data unit conveying data from a logical channel LCH configured with a set of logical channel parameters;

starting a first timer when transmitting the data unit to the network node;

determining to configure the logical channel with a modified set of logical channel parameters based on a state of the first timer;

configuring the logical channel with the modified set of logical channel parameters based on the determining; and

transmitting a data unit to the network node, the data unit conveying data from a logical channel configured with the set of modified logical channel parameters.

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