EP4691142A1

EP4691142A1 - Determining contention resolution

Info

Publication number: EP4691142A1
Application number: EP23931422.2A
Authority: EP
Inventors: Samuli Heikki TURTINEN; Chunli Wu; Matha DEGHEL; Timo Koskela
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2023-04-06
Filing date: 2023-04-06
Publication date: 2026-02-11
Also published as: CN120898506A; WO2024207354A1

Abstract

Embodiments of the present disclosure relate to a terminal device, a method and a medium for determining a contention resolution. A terminal device receives, as part of a random access (RA) procedure and after a Msg3 transmission, a physical downlink control channel transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission. The terminal device determines, based at least on a first timing advance group (TAG) identification (ID) associated with the UL grant and a second TAG ID indicated by a random access response (RAR) or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful. With the embodiments in the present disclosure, a network and a UE synchronization of time alignment timers running can be ensured and the UE cannot transmit uplink transmissions with wrong timing.

Description

DETERMINING CONTENTION RESOLUTION

FIELD

Various example embodiments generally relate to the field of communication, and in particular, to a terminal device, a method, an apparatus and a computer readable storage medium for determining a contention resolution.

BACKGROUND

In new radio (NR) systems, the concept and functionality of NR timing advance (TA) is substantially same as the long term evolution (LTE) timing advance. Briefly, TA is a special command (e.g. notification) from a network device to a terminal device that enables the terminal device to adjust its uplink transmission. This kind of uplink adjustment may apply to a physical uplink shared channel (PUSCH) , a physical downlink Control Channel (PDCCH) , a sounding reference signal (SRS) and so on.
In 3GPP release18, it was agreed to support two-TA enhancement for uplink (UL) multi-downlink control information (DCI) for multi-transmission and reception point (TRP) operation. However, solutions regarding multiple TAs need to be further studied.
SUMMARY
In general, example embodiments of the present disclosure provide a terminal device, a method, an apparatus and a computer readable storage medium for determining a contention resolution. For example, according to the solution for determining a contention resolution as provided in the present disclosure, a network and a UE synchronization of time alignment timers (TATs) running can be ensured and the UE cannot transmit UL transmissions with wrong timing.
In a first aspect, there is provided a terminal device. The terminal device may comprise at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, as part of a random access (RA) procedure and after a message 3 (Msg3) transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and determine, based at least on a first timing advance group (TAG) identification (ID) associated with the UL grant and a second TAG ID indicated by a random access response (RAR) or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In a second aspect, there is provided a method. The method may comprise: receiving, at a terminal device, as part of a random access (RA) procedure and after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and determining, at the terminal device and based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In a third aspect, there is provided an apparatus. The apparatus may comprise: means for receiving, at a terminal device, as part of a random access (RA) procedure andafter a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and means for determining based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In a fourth aspect, a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform a method comprising: receiving, as part of a random access (RA) procedure and after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and determining, based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In a fifth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: receive, as part of a random access (RA) procedure and after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and determine, based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In a sixth aspect, there is provided a terminal device. The terminal device may comprise a receiving circuitry configured to receive, as part of a random access (RA) procedure and after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and a determining circuitry configured to determine, based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, in which:
FIG. 1 illustrates an example network environment in which example embodiments of the present disclosure may be implemented;
FIG. 2 illustrates an example signaling process for determining a contention resolution in accordance with some example embodiments of the present disclosure;
FIG. 3 illustrates an example flowchart of a method implemented at a terminal device in accordance with some example embodiments of the present disclosure;
FIG. 4 illustrates an example simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure; and
FIG. 5 illustrates an example block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.
Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein may be implemented in various manners other than the ones described below.
In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which the present disclosure belongs.
References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
It may be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.
As used in this application, the term “circuitry” may refer to one or more or all of the following:
(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and
(b) combinations of hardware circuits and software, such as (as applicable) :
(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and
(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and
(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.
This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
As used herein, the term “communication network” refers to a network following any suitable communication standards, such as long term evolution (LTE) , LTE-advanced (LTE-A) , wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , narrow band Internet of things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or beyond. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.
As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a remote radio unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.
The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a subscriber station (SS) , a portable subscriber station, a mobile station (MS) , or an access terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial, a relay node, an integrated access and backhaul (IAB) node, and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.
As used herein, the term “TRP” refers to a transmit-receive point having an antenna array (with one or more antenna elements) at the network side located at a specific geographical location, which may be used for transmitting and receiving signals to/from the terminal device. In embodiment of the present disclosure, a TRP may refer to Macro Cell, micro cell, an RRH, a relay, a femto node, a pico node, etc. Although some embodiments of the present disclosure are described with reference to two TRPs for example, these embodiments are only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitations as to the scope of the present disclosure. It is to be understood that the present disclosure described herein can be implemented in various manners other than the ones described below.
As used herein, the term “resource” , “transmission resource” , “resource block” , “physical resource block” (PRB) , “uplink (UL) resource” or “downlink (DL) resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, a resource in a combination of more than one domain or any other resource enabling a communication, and the like. In the following, a resource in time domain (such as, a subframe) will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.
As discussed above, TA is a special command (e.g. notification) from a network device to a terminal device that enables the terminal device to adjust its uplink transmission. TA is a special command (e.g. notification) from the network device to the terminal device that enables the terminal device to adjust its uplink transmission.
TA can be delivered to a terminal device through RAR or MAC CE. A TA loop can be used to maintain the TA to enable alignment of UL signals (transmitted from a terminal device) at a network node within a certain time resolution. In a random access procedure, the terminal device may receive an initial TA value (e.g., an absolute TA value) in a RAR message. The TA value may then be updated with a MAC CE containing a TAC indicating a relative TA value. In addition, the UE may also autonomously update the TA by initiatively request an updated TA value. These operations of maintain the TA is called as a TA loop. Usually, a TA loop may correspond to UL transmissions toward a given TRP. In addition, a TA loop may correspond to TA maintained within a TAG. Therefore, one TA loop may correspond to one TA and the number of TA loops may indicate the number of used TAs. Thus, in the present disclosure, a TA loop may refer to a TA implicitly.
A timing advance group (TAG) used herein means a group consists of one or more serving cells with the same uplink TA and same downlink timing reference cell. Each TAG contains at least one serving cell with configured uplink, and the mapping of each serving cell to a TAG is configured by a RRC signal. In 3GPP release 18, it was already agreed to support, in NR system, two TAs for UL multi-DCI for multi-TRP operation. In addition, the support of two TA enhancement has been agreed for both intra-cell and inter-cell multi-DCI multi-TRP scenarios in 3GPP release 18.
Release 18 work item on further new radio (NR) mobility enhancements is ongoing in 3GPP. The multiple (two) timing advance values for a UE within a serving cell will be further discussed in, for example, NR MIMO evolution WID (RP-223276) , as shown in table 1
TABLE 1
Further, MAC TS 38.321 specifies the contention resolution/successful RA procedure completion in RRC_CONNECTED mode as follows for 4-step RA and 2-step RA respectively, as shown in table 2.
TABLE 2
Since in the multi-TRP scenario, the UE would have 2 TAGs for a serving cell (such as a SpCell) , these TAGs would naturally employ different TATs for the network to be able to provide separate timing adjustment commands using e.g., TAC MAC CE, and hence, the TATs may be started or restart in different times for these two TAGs.
Typically, in multi-TRP scenario within a serving cell, subset of the synchronization signal and physical broadcast channel blocks (SSBs) in the cell would be transmitted by one TRP and another subset of the SSBs by another TRP. When UE performs random access procedure, it selects one of these SSBs and, hence, may transmit the PRACH preamble to either one of the TRPs.
Therefore, when SpCell is configured with two TAGs, one of the TATs associated with these TAGs may not be running or has expired. Contention-based random access (CBRA) procedure may be triggered at any point in time for various reasons at the UE. For example, due to scheduling request (SR) when SR resources are not configured, number of SR transmissions reaches a configured threshold, beam failure recovery (BFR) , or due to consistent listen-before-talk (LBT) failure detection.
The RAR or fallbackRAR may be able to indicate the TAG ID for which the TAC of the RA procedure applies. If the TAT associated with the indicated TAG ID is not running, the UE would start or restart the TAT based on the indication upon receiving the RAR/fallbackRAR. Similarly, it is assumed the UE may be able to determine the TAG ID corresponding to the UL grant provided for successful contention resolution.
However, the UE behaviour is not clear in terms of contention resolution if UL grant associated with the TAG ID which is not the TAG ID indicated by the RAR/fallbackRAR is received. This may lead to unsynchornization between UE and the network of the running statuses of different TATs at the UE which may lead to erroneous transmissions to UL with wrong timing.
Example embodiments of the present disclosure provide a solution for determining a contention resolution and/or successful RA procedure completion. According to embodiments of the present disclosure, a terminal device receives, after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission. The terminal device determines, based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, a contention resolution as successful or unsuccessful. It is to be understood that the above procedure steps may work together, in a flow of operations as described in the next section, partly together or independently of each other. It is also to be understood that while below text refers to determining a contention resolution, it may be equally understood that the terminal device may determine also or instead a random access procedure completion. It is also to be understood that while below text refers to determining a contention resolution as successful or unsuccessful, it may be equally understood that the terminal device may determine also or instead a random access procedure as successfully or unsuccessfully completed, respectively.
According to the example embodiments for determining a contention resolution as provided in the present disclosure, a network and a UE synchronization of time alignment timers running can be ensured and the UE cannot transmit uplink transmissions with wrong timing.
For illustrative purposes, principle and example embodiments of the present disclosure for determining resource blocks for transmissions will be described below with reference to FIG. 1-FIG. 5. However, it is to be noted that these embodiments are given to enable the skilled in the art to understand inventive concepts of the present disclosure and implement the solution as proposed herein, and not intended to limit scope of the present application in any way.
Reference is made to FIG. 1, which illustrates an example of a communication network 100 in which some example embodiments of the present disclosure may be implemented. As illustrated in FIG. 1, the communication network 100 includes a terminal device (which may also be referred to as user equipment or UE) 102 and two network devices (which may also be referred to as a gNB or BS or TRP) , such as the network devices 104-1 and 104-2 (can also be referred collectively as “network devices 104” ) . Although the terminal device 102 and two network devices 104 are shown in FIG. 1, the numbers of the network devices and the terminal devices are not limited. In other words, there may be one or more network devices 104 and one or more terminal devices 102 in the communication network 100.
The network device 104 can provide services to the terminal device 102, and the network device 104 and the terminal device 102 may communicate data and control information with each other. In some example embodiments, the network device 104 and the terminal device 102 may communicate with direct links/channels.
In the communication system 100, a link from the network device 104 to the terminal device 102 is referred to as a downlink (DL) , while a link from the terminal device 102 to the network device 104 is referred to as an uplink (UL) . In downlink, the network devices 104 are transmitting (TX) devices (or transmitters) and the terminal device 102 is a receiving (RX) device (or a receiver) . In uplink, the terminal device 102 is a transmitting (TX) device (or a transmitter) and the network devices 104s are RX device (or receiver) . It is to be understood that the network devices 104 may provide one or more serving cells. As illustrated in FIG. 1, the network devices 104 together provide a serving cell 106, and the terminal device 102 camps on the serving cell 106. In some embodiments, the network devices 104 can provide multiple serving cells and the terminal device 102 may switch from a source cell to a target cell between the serving cells during its mobility. It is to be understood that the number of serving cell (s) shown in FIG. 1 is for illustrative purposes without suggesting any limitation.
Communications in the network environment 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.
In some embodiments, the serving cell 106 may comprise a primary cell, a primary secondary cell, or a secondary cell with multiple network devices 104, such as TRPs. In some embodiments, the network devices 104 may transmit two different PDSCH and each network device 104 transmits its own corresponding PDCCH/DCI. In some embodiments, the network devices may jointly transmit DL signals and receive UL signals. In some example embodiments, two timing advance values for a UE within a serving cell can be configured. In some example embodiments, multiple timing advance values for a UE within a serving cell can be configured. Hereafter, we will discuss a scenario of a two timing advance values for a UE within a serving cell, but without limiting the scope of the present application.
As mentioned, the terminal device 102 may have two or more TAGs for the serving cell 106 and employ different TATs for one or more the network devices to be able to provide separate TACs for these TAGs. The terminal device 102 may determine one of the TAGs is a primary TAG and the other is a secondary TAG.
It is to be understood that the number of devices and their connection relationships and types shown in FIG. 1 are for illustrative purposes without suggesting any limitation. The communication system 100 may comprise any suitable number of devices adapted for implementing embodiments of the present disclosure.
Reference is made to FIG. 2, which illustrates an example signaling process 200 for determining a contention resolution in accordance with some example embodiments of the present disclosure. As shown, as part of a RA procedure and after a Msg3 transmission (for example, after the terminal device 102 transmitted a Msg3 transmission to the network device 104) , the terminal device 102 receives (204) a PDCCH transmission (206) after a Msg3 transmission. The PDCCH transmission (206) is associated with a serving cell and addressed to an identifier of the terminal device and contains an UL grant for a new transmission. In some example embodiments, the network device 104 may transmit (202) the PDCCH transmission (206) to the terminal device 102.
The terminal device 102 determines (208) the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful based at least on a first timing advance group TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device 102. It is to be understood that while the text refers to a TAG ID association with a UL grant, it can be equally understood that the TAG with the TAG ID is associated with the UL grant.
As an example, when the terminal device 102 receives a PDCCH transmission addressed to the C-RNTI which contains a UL grant for a new transmission after Msg3 transmission (i.e., while ra-ContentionResolutionTimer is running) , if the UL grant is associated with the first TAG ID which is different to the TAG ID (second TAG ID) indicated by the RAR or fallbackRAR, and if the TAT associated with the second TAG ID was started or restarted based on the TAC and the indicated TAG ID by the RAR or fallbackRAR (i.e., the TAT was not running upon receiving the RAR/fallbackRAR) , the terminal device 102 may stop the TAT associated with the second TAG indicated by the RAR or fallbackRAR upon receiving the UL grant or upon determining successful contention resolution or RA procedure completion.
In some example embodiments, if the UL grant is associated with the first TAG ID which is different to the TAG ID (second TAG ID) indicated by the RAR or fallbackRAR, and if the TAT associated with the second TAG ID was started or restarted based on the TAC and the indicated TAG ID by the RAR or fallbackRAR (i.e., the TAT was not running upon receiving the RAR or fallbackRAR) , and if the TAT associated with the first TAG ID is running, the terminal device 102 may stop the RA procedure. In some example embodiments, at this point, the terminal device may stop the TAT associated with the second TAG indicated by the RAR or fallbackRAR.
In some example embodiments, if the UL grant is associated with the first TAG ID which is different to the TAG ID (second TAG ID) indicated by the RAR or fallbackRAR, and if the TAT associated with the first TAG ID is not running, the RA procedure or the contention resolution of the RA procedure may be considered unsuccessful by the terminal device 102.
In some example embodiments, based on determining that the RA procedure or the contention resolution of the RA procedure is considered unsuccessful, the terminal device 102 may ignore the UL grant. In some example embodiments, the TAT associated with TAG with the second TAG ID may be stopped. In some example embodiments, the terminal device 102 may select a random backoff time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF parameter and the terminal device 102 may perform the random access resource selection procedure after the backoff time.
In some example embodiments, if the UL grant is associated with the first TAG ID which is different to the TAG ID (second TAG ID) indicated by the RAR or fallbackRAR, the DCI scheduling the UL grant may indicate that if the UL grant is in response to Msg3 transmission or for a successful RA procedure or a successful contention resolution of the RA procedure. In some example embodiments, based on this indication, the terminal device 102 may keep the TAT associated with the TAG with the second TAG ID running after a successful RA procedure or a successful contention resolution of the RA procedure.
In some example embodiments, the UL grant associated with the TAG ID as indicated by the RAR or fallbackRAR may be considered as a successful RA procedure or a successful contention resolution of the RA procedure. In some example embodiments, only UL grant associated with the TAG ID as indicated by the RAR or fallbackRAR may be considered as a successful RA procedure or a successful contention resolution of the RA procedure. This may ensure the TAT of the TAG ID used for UL transmission with the UL grant is always running.
In some example embodiments, if for the PRACH transmission the terminal device 102 selects a preamble corresponding to an SSB which is associated to a physical cell identity (PCI) , and this PCI corresponds to a first TAG ID, and if the UL grant is associated with the first TAG ID which is different from the second TAG ID, and if the TAT associated with the first TAG ID is not running, the contention resolution may be considered not successful. In some example embodiments, based on the contention resolution is considered not successful, the terminal device 102 may ignore the UL grant. In some example embodiments, the TAT associated with the second TAG ID may be stopped.
In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG ID based on the CORESET scheduling the UL grant. For example, the TAG ID is associated with the CORESETpoolIndex value configured for the CORESET, and UL channels may be configured to be associated with a CORESETpoolindex.
In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG ID based on indicated TCI state of the UL grant. For example, the indicated TCI state may be (unified) joint DL/UL TCI State or (unified) UL TCI State, or TCI state ID itself, or the SRS resource (s) used as reference for uplink transmission.
In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG ID based on TAG ID associated with the TCI state indicated or configured for the UL transmission scheduled by the UL grant.
In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG ID based on TAG ID corresponding to the PCI (physical cell ID) associated with the DL RS comprised in the TCI state indicated or configured for the UL transmission scheduled by the UL grant. In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG ID based on indication in the UL grant.
By implementing FIG. 2, the example embodiments for determine a contention resolution can allow that a network and a UE synchronization of time alignment timers (TATs) running can be ensured and the UE cannot transmit UL transmissions with wrong timing.
Reference is made to FIG. 3, which illustrates an example flowchart 300 of a method implemented at a terminal device in accordance with some example embodiments of the present disclosure. Reference will be made in combination with FIG. 1.
At 302, the terminal device 102 receives a PDCCH transmission as part of a RA procedure and after a Msg3 transmission. The PDCCH transmission is associated with a serving cell, and the PDCCH transmission is addressed to an identifier of the terminal device 102. The PDCCH transmission contains a UL grant for a new transmission.
At 304, the terminal device 102 determines the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device 102.
In some example embodiments, the terminal device 102 may stop a second TAT associated with the second TAG ID based on determining that the first TAG ID and the second TAG ID are different.
In some example embodiments, the terminal device 102 may stop the second TAT based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a second TAT associated with the second TAG ID is not running upon receiving the RAR or the fallbackRAR, and based on determining that the first TAT associated with the first TAG ID is running.
In some example embodiments, the terminal device 102 may determine that the RA procedure or the contention resolution of the RA procedure is unsuccessful based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a first TAT associated with the first TAG ID is not running.
In some example embodiments, based on the RA procedure or the contention resolution of the RA procedure is unsuccessful, the terminal device 102 may ignore the UL grant. In some example embodiments, the terminal device 102 may stop the second TAT. In some example embodiments, the terminal device 102 may select a backoff time. In some example embodiments, the terminal device 102 may perform a random access resource selection procedure after the backoff time.
In some example embodiments, the terminal device 102 may keep, based on determining that the first TAG ID and the second TAG ID are different, and based on determining that DCI comprises an indication indicative of whether the UL grant is in response to the Msg3 transmission or is for a successful RA procedure or a successful contention resolution of the RA procedure, the second TAT running after the successful RA procedure or the successful contention resolution of the RA procedure based on the indication
In some example embodiments, the terminal device 102 may determine based on determining that the first TAG ID and the second TAG ID are the same, that the RA procedure or the contention resolution of the RA procedure is successful.
In some example embodiments, the terminal device 102 may determine, based on determining that the first TAG ID corresponds to a PCI associated with a synchronization signal and physical SSB, wherein the SSB corresponds to a preamble which the terminal device selects, and based on determining that the first TAG ID and the second TAG ID are different, and based on determining that the first TAG ID is not running, that the RA procedure or the contention resolution of the RA procedure is unsuccessful.
In some example embodiments, based on the RA procedure or the contention resolution of the RA procedure is unsuccessful, the terminal device 102 may ignore the UL grant. In some example embodiments, the terminal device 102 may stop the second TAT.
In some example embodiments, the terminal device 102 may determine the association between the UL grant and the TAG among the multiple TAGs based on at least one of the following: a CORESET scheduling the UL grant; an indicated TCI state of the UL grant; a TAG ID associated with a TCI state indicated or configured for the UL transmission scheduled by the UL grant; a TAG ID corresponding to a PCI associated with a DL RS comprised in a TCI state indicated or configured for the UL transmission scheduled by the UL grant; or an indication in the UL grant.
By implementing the method 300, a network and a UE synchronization of time alignment timers running can be ensured and the UE cannot transmit UL transmissions with wrong timing.
It is understood that the example embodiments of the present disclosure may be specified in TS 38.321, TS 38.212, TS 38.213, TS 38.300 as shown in tables 3 and 4. The texts underlined are to be specified.
TABLE 3
TABLE 4
In some example embodiments, an apparatus capable of performing the method 300 may comprise means for performing the respective steps of the method 300. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
In some example embodiments, the apparatus may comprise means for receiving, as part of a RA procedure and after a Msg3 transmission, a PDCCH transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains a UL grant for a new transmission; and means for determining, based at least on a first TAG ID associated with the UL grant and a second TAG ID indicated by a RAR or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
In some example embodiments, the apparatus may further comprise means for based on determining that the first TAG ID and the second TAG ID are different, stopping a second TAT associated with the second TAG ID.
In some example embodiments, the apparatus may comprise means for based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a second TAT associated with the second TAG ID is not running upon receiving the RAR or the fallbackRAR, and based on determining that the first TAT associated with the first TAG ID is running, stopping the second TAT.
In some example embodiments, the apparatus may comprise means for based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a first TAT associated with the first TAG ID is not running, determining that the RA procedure or the contention resolution of the RA procedure is unsuccessful.
In some example embodiments, the apparatus may comprise means for ignoring the UL grant. In some example embodiments, the apparatus may comprise means for stopping the second TAT. In some example embodiments, the apparatus may comprise means for selecting a backoff time. In some example embodiments, the apparatus may comprise means for performing a random access resource selection procedure after the backoff time.
In some example embodiments, the apparatus may comprise means for based on determining that the first TAG ID and the second TAG ID are different, and based on determining that DCI comprises an indication indicative of whether the UL grant is in response to the Msg3 transmission or is for a successful RA procedure or a successful contention resolution of the RA procedure, keeping the second TAT running after the successful RA procedure or the successful contention resolution of the RA procedure based on the indication.
In some example embodiments, the apparatus may comprise means for based on determining that the first TAG ID and the second TAG ID are the same, determining that the RA procedure or the contention resolution of the RA procedure is successful.
In some example embodiments, the apparatus may comprise means for based on determining that the first TAG ID corresponds to a PCI associated with a synchronization signal and physical SSB, wherein the SSB corresponds to a preamble which the terminal device selects, and based on determining that the first TAG ID and the second TAG ID are different, and based on determining that the first TAG ID is not running, determining that the RA procedure or the contention resolution of the RA procedure is unsuccessful.
In some example embodiments, the apparatus may comprise means for ignoring the UL grant. In some example embodiments, the apparatus may comprise means for stopping the second TAT.
In some example embodiments, the apparatus may further comprise means for determining the association between the UL grant and the TAG among the multiple TAGs based on at least one of the following: a CORESET scheduling the UL grant; an indicated TCI state of the UL grant; a TAG ID associated with a TCI state indicated or configured for the UL transmission scheduled by the UL grant; a TAG ID corresponding to a PCI associated with a DL RS comprised in a TCI state indicated or configured for the UL transmission scheduled by the UL grant; or an indication in the UL grant.
In some embodiments, the apparatus may further comprise means for performing other steps in some embodiments of the method 300. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.
Reference is made to FIG. 4, which illustrates an example simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure. The device 400 may be provided to implement the communication device, for example the terminal device 102 as shown in FIG. 1. As shown, the device 400 includes one or more processors 410, one or more memories 420 may couple to the processor 410, and one or more communication modules 440 may couple to the processor 410.
The communication module 440 is for bidirectional communications. The communication module 440 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements, for example the communication interface may be wireless or wireline to other network elements, or software based interface for communication.
The processor 410 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 400 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.
The memory 420 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a read only memory (ROM) 424, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 422 and other volatile memories that will not last in the power-down duration.
A computer program 430 includes computer executable instructions that are executed by the associated processor 410. The program 430 may be stored in the ROM 424. The processor 410 may perform any suitable actions and processing by loading the program 430 into the RAM 422.
The embodiments of the present disclosure may be implemented by means of the program so that the device 400 may perform any process of the disclosure as discussed with reference to FIG. 2 to FIG. 3. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.
In some embodiments, the program 430 may be tangibly contained in a computer readable medium which may be included in the device 400 (such as in the memory 420) or other storage devices that are accessible by the device 400. The device 400 may load the program 430 from the computer readable medium to the RAM 422 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. FIG. 5 shows an example of the computer readable medium 500 in form of CD or DVD. The computer readable medium has the program 430 stored thereon.
Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects 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. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method 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.
The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 300 as described above with reference to FIG. 3. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.
Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.
The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .
Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.
Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A terminal device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:

receive, as part of a random access (RA) procedure and after a message 3 (Msg3) transmission, a physical downlink control channel (PDCCH) transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains an uplink (UL) grant for a new transmission; and

determine, based at least on a first timing advance group (TAG) identification (ID) associated with the UL grant and a second TAG ID indicated by a random access response (RAR) or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the the RA procedure as successful or unsuccessful.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID and the second TAG ID are different, stop a second time alignment timer (TAT) associated with the second TAG ID.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a second TAT associated with the second TAG ID is not running upon receiving the RAR or the fallbackRAR, and based on determining that the first TAT associated with the first TAG ID is running, stop the second TAT.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID and the second TAG ID are different, and based on determining that a first TAT associated with the first TAG ID is not running, determine that the RA procedure or the contention resolution of the RA procedure is unsuccessful.
The terminal device of claim 4, wherein the terminal device is further caused to perform at least one of the following:

ignore the UL grant;

stop the second TAT; or

select a backoff time, and perform a random access resource selection procedure after the backoff time.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID and the second TAG ID are different, and based on determining that downlink control information (DCI) comprises an indication indicative of whether the UL grant is in response to the Msg3 transmission or is for a successful RA procedure or a successful contention resolution of the RA procedure, keep the second TAT running after the successful RA procedure or the successful contention resolution of the RA procedure based on the indication.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID and the second TAG ID are the same, determine that the RA procedure or the contention resolution of the the RA procedure is successful.
The terminal device of claim 1, wherein the terminal device is further caused to:

based on determining that the first TAG ID corresponds to a physical cell identity (PCI) associated with a synchronization signal and physical broadcast channel block (SSB) , wherein the SSB corresponds to a preamble which the terminal device selects, and based on determining that the first TAG ID and the second TAG ID are different, and based on determining that the first TAG ID is not running, determine that the RA procedure or the contention resolution of the RA procedure is unsuccessful.
The terminal device of claim 8, wherein the terminal is further caused to perform at least one of the following:

ignore the UL grant; or

stop the second TAT.
The terminal device of any of claims 1-9, wherein the terminal device is further caused to:

determine an association between the UL grant and the first TAG ID based on at least one of the following:

a control resource set (CORESET) scheduling the UL grant;

an indicated transmission configuration indication (TCI) state of the UL grant;

a TAG ID associated with the TCI state indicated or configured for the UL transmission scheduled by the UL grant;

a TAG ID corresponding to the PCI associated with the DL reference signal (RS) comprised in the TCI state indicated or configured for the UL transmission scheduled by the UL grant; or

an indication in the UL grant.
A method comprising:

receiving, at a terminal device, as part of a random access (RA) procedure and after a message 3 (Msg3) transmission, a physical downlink control channel (PDCCH) transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains an uplink (UL) grant for a new transmission; and

determining, at the terminal device and based at least on a first timing advance group (TAG) identification (ID) associated with the UL grant and a second TAG ID indicated by a random access response (RAR) or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.
A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform a method comprising:

receiving, as part of a random access (RA) procedure and after a message 3 (Msg3) transmission, a physical downlink control channel (PDCCH) transmission which is associated with a serving cell and addressed to an identifier of the terminal device and contains an uplink (UL) grant for a new transmission; and

determining, based at least on a first timing advance group (TAG) identification (ID) associated with the UL grant and a second TAG ID indicated by a random access response (RAR) or a fallbackRAR received by the terminal device, the RA procedure or a contention resolution of the RA procedure as successful or unsuccessful.