Method and apparatus for supporting urllc service

Abstract

This disclosure provides a method for a user equipment to determine a radio wave delay time value, the method comprising the steps of: requesting a radio wave delay time from a base station; transmitting a time measurement signal via time measurement resources allocated by the base station; receiving a response from the base station including an extended timing advance command (extended TA command); and applying time information and starting a timer based on the received response. This disclosure also provides a method for a user equipment to perform communication in an unlicensed frequency band, the method comprising determining whether to transmit data via a configured license (CG), comparing the priority between the CG and uplink resources, and changing the priority of the CG based on a listen-before-tell (LBT) failure.

Description

Technical Field

[0001] This disclosure relates to methods and apparatus for supporting ultra-reliable and low-latency (URLLC) services. Background Technology

[0002] Efforts are underway to develop and improve fifth-generation (5G) or pre-5G communication systems to keep pace with the growing demand for wireless data services following the commercialization of fourth-generation (4G) communication systems. For this purpose, 5G or pre-5G communication systems are referred to as super-4G network communication systems or post-Long Term Evolution (LTE) systems. The implementation of 5G communication systems in ultra-high frequency (millimeter wave (mmWave)) bands (e.g., the 60-GHz band) is being considered to achieve high data transmission rates. To mitigate path loss of radio waves and increase transmission distance in the ultra-high frequency bands of 5G communication systems, technologies such as beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antennas are being researched. Furthermore, to improve the system network for 5G communication systems, various technologies are currently being developed, including evolved small cells, advanced small cells, cloud radio access networks (cloud-RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receive interference cancellation. In addition, for 5G systems, advanced coding and modulation (ACM) schemes, such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), as well as advanced access technologies, such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA), are being developed.

[0003] Furthermore, the internet has evolved from a human-centric connectivity network (where humans create and consume information) to an Internet of Things (IoT) network (where distributed components, such as objects, exchange information with each other to process information). The Internet of Everything (IoE) technology has emerged, where IoT technology is combined with technologies for processing big data, such as connecting to cloud servers. To realize IoT, technologies such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required. Therefore, technologies such as sensor networks for interconnected objects, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been researched. In the IoT environment, intelligent internet technology services can be provided, creating new value for human life by collecting and analyzing data obtained from interconnected objects. IoT can be applied to various fields, such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services, through the convergence and integration of existing information technology (IT) with various industries.

[0004] Therefore, various attempts are underway to apply 5G communication systems to IoT networks, including technologies such as sensor networks, M2M communication, and MTC. These are being implemented using 5G communication technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN, as a big data processing technology, can serve as an example of the convergence between 5G and IoT technologies.

[0005] As mentioned above, with the development of mobile communication systems, various services can be provided, and in particular, there is a need for a more accurate method to measure and apply the latency between user equipment (UE) and base station. Summary of the Invention

[0006] Technical solution

[0007] This disclosure relates to methods and apparatus for supporting Ultra Reliable Low Latency (URLLC) services. Attached Figure Description

[0008] Figure 1a It is a graph used to describe the difference between the base station's transmission time and the user equipment's (UE) reception time in each cell.

[0009] Figure 1b This is a diagram illustrating the process by which a base station sends accurate time information to a UE according to an embodiment of the present disclosure.

[0010] Figure 1c This is a diagram illustrating a method for applying more refined timing information according to embodiments of the present disclosure.

[0011] Figure 1d This is a diagram illustrating a method for randomly accessing preamble resources during an allocation period according to an embodiment of this disclosure.

[0012] Figure 1e This is a diagram illustrating a method for applying more refined timing information according to embodiments of the present disclosure.

[0013] Figure 1f This is a diagram illustrating the format of a random access response message.

[0014] Figure 1g This is a diagram illustrating the format of a random access response message according to an embodiment of this disclosure.

[0015] Figure 1h This is a diagram illustrating the format of an extended timing advance (TA) command message according to an embodiment of the present disclosure.

[0016] Figure 1i This is a diagram illustrating the format of an extended TA command message according to an embodiment of this disclosure.

[0017] Figure 1jThis is a diagram illustrating the detailed operation of a synchronization timer according to an embodiment of the present disclosure.

[0018] Figure 1k This is a diagram illustrating a method for applying more refined time information according to an embodiment of the present disclosure.

[0019] Figure 11 This is a diagram illustrating the format of a propagation delay message according to an embodiment of the present disclosure.

[0020] Figure 1m A method for applying a more refined TA value according to embodiments of the present disclosure is shown.

[0021] Figure 1n A method for applying more refined propagation delay values ​​according to embodiments of the present disclosure is shown.

[0022] Figure 1o This is a diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0023] Figure 1p This is a diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0024] Figure 1q This is a diagram illustrating the format of a propagation delay message according to an embodiment of the present disclosure.

[0025] Figure 1r It is a diagram used to describe the time difference that occurs between base stations at a reference time point.

[0026] Figure 1s This is a diagram illustrating a process for transmitting time information from other base stations according to an embodiment of the present disclosure.

[0027] Figure 2a This is a diagram illustrating the operation of the configuration configuration license (CG) and hybrid automatic repeat request (HARQ) process according to an embodiment of this disclosure.

[0028] Figure 2b A method for performing retransmission on a CG in an unlicensed spectrum is illustrated according to an embodiment of the present disclosure.

[0029] Figure 2c The present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum according to an embodiment of the present disclosure.

[0030] Figure 2d The present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum according to an embodiment of the present disclosure.

[0031] Figure 2e The present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum according to an embodiment of the present disclosure.

[0032] Figure 2f The present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum according to an embodiment of the present disclosure.

[0033] Figure 2g The operation process according to an embodiment of the present disclosure is illustrated when Listen-Before-Speak (LBT) fails in unlicensed spectrum.

[0034] Figure 2h This is a diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0035] Figure 2i This is a diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0036] Implementation

[0037] According to embodiments of this disclosure, a method for determining a propagation delay value performed by a user equipment (UE) may include: requesting a propagation delay from a base station; transmitting a time measurement signal on time measurement resources allocated by the base station; receiving a response from the base station including an extended timing advance (TA) command; and applying time information and starting a timer based on the received response.

[0038] According to another embodiment of this disclosure, a method for performing communication in an unlicensed spectrum by a UE may include: determining whether to send data via a configured license (CG), comparing the priority of the CG and uplink resources, and changing the priority of the CG based on a listen-before-talk (LBT) failure. Detailed Implementation

[0039] In the following description of this disclosure, descriptions of known functionalities or configurations will be omitted where it is determined that such detailed descriptions might unnecessarily obscure the subject matter of this disclosure. Embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0040] Figure 1a It is a graph used to describe the difference between the base station's transmission time and the user equipment's (UE) reception time in each cell.

[0041] refer to Figure 1aWhen radio waves travel from a transmitting device to a receiving device, the propagation time is proportional to the distance the radio waves travel (1a-35). In this case, the speed of the radio waves can be assumed to be the speed of light. Therefore, due to the propagation time required between the transmitting and receiving devices, there is a time difference between them relative to the same reference time. Because of this propagation time 1a-30, a time difference, such as propagation time 1a-30, may occur between the time 1a-10 when the base station transmits in the downlink (DL) and the time 1a-20 when the UE receives in the DL. Therefore, there is a difference between frames 1a-11, 1a-12, and 1a-13 transmitted by the base station based on the transmission time and frames 1a-21, 1a-22, and 1a-23 received by the UE based on the reception time. Propagation time 1a-30 is also referred to as propagation delay.

[0042] When a base station sends time information at a reference time point to a UE, it needs to be configured whether to use the base station's transmission time or the UE's reception time as the reference. Furthermore, it needs to compensate for the error between the two times, i.e., the propagation delay, so that the time information can be accurately processed according to the configured reference. For example, to use the base station's transmission time as the reference, the base station can notify the UE of the difference between the UE's reception time and transmission time, i.e., information about the actual propagation time 1a-30 required for transmission from the base station to the UE. Information about the propagation time 1a-30 can be included in the time information message sent by the base station to the UE, or it can be sent as a separate message. In embodiments of this disclosure, half of the timing advance (TA) value used when the UE advances the message transmission time relative to the reception time by a specific amount can be used as the difference between the base station's transmission time and the UE's reception time. In another embodiment of this disclosure, to use the UE's reception time as the reference, the base station can include in the time information a value obtained by adding the propagation time 1a-30 to the actual transmission time, taking into account the propagation time required for transmission to the UE, and then send the time information. Furthermore, the time information message can indicate whether the base station's transmission time or the UE's reception time is used as the reference time. Regardless of whether the base station's transmission time or the UE's reception time is used as the reference time, the UE can update the time information based on the end point of the time slot, the start point of the time slot, or a frame indicated by the base station. This time information can apply the end point of the time slot, the start time of the time slot, or a frame indicated by the base station based on a specific cell agreed upon by the base station and the UE. The specific cell can be the primary cell (PCell). In another embodiment of this disclosure, the specific cell can be a primary-secondary cell (PSCell) or a cell configured by the base station.

[0043] Figure 1bThis is a diagram illustrating the process by which a base station sends accurate time information to a UE according to an embodiment of the present disclosure.

[0044] refer to Figure 1b In order to operate by connecting to Ultra Reliable and Low Latency Communication (URLLC) services or Time-Sensitive Networking (TSN) networks, the UE 1b-10 needs accurate time information to function within the communication system. This time information requires accuracy ranging from a few nanoseconds (ns) to hundreds of nanoseconds. If such accuracy is not guaranteed, the Quality of Service (QoS) requirements of URLLC services or TSN may not be met. In other words, the base station and the UE need to synchronize with each other with a finer degree of accuracy.

[0045] Therefore, UE 1b-10 can receive accurate time information 1b-30 from base station 1b-20. In embodiments of this disclosure, the time information may include the time used in the communication network accessed and used by the UE. Furthermore, the time information may include a time consistent with the time provided by a specific satellite, or a time different from it within an allowable error range. When the time information includes the time used in the communication network, a reference time point may be needed to indicate the time in the time information. For example, the reference time point may be the end boundary of a specific cell indicated by a system frame number (SFN), slot number, or symbol number. In other words, the time information may include information about the reference time point indicated by the time information and the time of the reference time point. Here, the specific cell may be a PCell. Furthermore, uncertainty indicating the degree of accuracy of the time information may be transmitted in the time information.

[0046] In embodiments of this disclosure, upon receiving time information, UE 1b-10 can apply this time information to accurately determine the time (1b-40) of the communication system to which UE 1b-10 is connected. In this case, UE 1b-10 can apply the reference time point when base station 1b-20 sends the time information, or the reference time point when the UE receives the corresponding message. If the time sent by the base station to the UE is the time used by the communication network, i.e., the time used by the base station, then the UE must apply the received time information 1b-30 by compensating for the propagation time 1a-30 between the base station and the UE. This propagation time can be half of the TA value sent by the base station, or it can be the propagation time value directly sent by the base station to the UE.

[0047] In another embodiment of this disclosure, UE 1b-10 may receive time information from base station 1b-20 via a time information message. However, this disclosure is not limited thereto, and UE 1b-10 may receive time information from base station 1b-20 in various ways (such as in forms other than messages).

[0048] Figure 1cThis is a diagram illustrating a method for applying more refined timing information according to embodiments of the present disclosure.

[0049] refer to Figure 1c In order to operate by connecting to URLLC services or TSN networks, the UE 1c-10 needs accurate time information to function within the communication system. This time information requires accuracy ranging from a few nanoseconds to hundreds of nanoseconds. If such accuracy cannot be guaranteed, the QoS requirements of URLLC services or TSN may not be met. Therefore, as... Figure 1b As shown, the base station can send more refined time information to the UE (1b-30). However, if the propagation delay between the base station and the UE is not properly compensated, the time information sent from the base station to the UE will have errors. Therefore, the UE needs to apply propagation time with a more refined degree of accuracy by using more refined propagation delay information.

[0050] In some cases, the base station may have difficulty determining which UE requires more granular propagation delay information. Therefore, UE1c-10 can send a message to base station 1c-20 indicating whether it requires more granular propagation delay information. That is, the UE can request a more granular propagation delay value from the base station (1c-30). The message requesting a more granular propagation delay value can include information indicating that the corresponding UE requires more granular propagation delay, as well as the accuracy value of the required more granular propagation delay. The message may also include the accuracy value of the propagation delay expected by the UE. In some cases, this accuracy value can be replaced by a value such as uncertainty.

[0051] Subsequently, the base station can measure the propagation delay between the UE and the base station. The propagation delay measurement can be performed using a random access (RA) procedure. The base station can allocate RA resources (1c-40) to the UE for propagation delay measurement. In related technologies, the base station can allocate RA resources to the UE, and the allocation of RA resources is for applying a TA value indicating the time at which the UE begins uplink (UL) transmission to the base station. However, embodiments of this disclosure are intended to apply time information by compensating for propagation delay when applying time information sent by the base station to the UE, which may not be directly related to determining the start time of UL transmission by applying the TA value. Furthermore, the time information 1b-30 sent by the base station to the UE may need to have a finer degree of accuracy than the TA value. Therefore, the RA performed on the RA source for propagation delay measurement (i.e., the RA preamble 1c-50 sent for propagation delay measurement) can have a different accuracy than existing RA resources. For this purpose, RA resources with a high degree of accuracy in propagation delay measurement can be distinguished from existing RA resources. In some cases, this can be identified by the RA preamble index, and RA preamble resources with a specific index value can be classified and used as RA resources with a finer degree of accuracy. In some cases, index values ​​greater than (or greater than or equal to) a specific index value can be classified and used as RA resources with a finer degree of accuracy. For the purpose of measuring propagation delay, or in cases where a finer degree of accuracy of RA is required, RA preamble 1c-50 can be sent using RA resources classified as described above. Base station 1c-20, which has already received the RA preamble on the classified RA resources, can send a finer propagation delay value (1c-60) to the UE in the RA response (RAR) message. According to another embodiment of this disclosure, the TA value can be included in the RAR message instead of propagation delay information, and in this case, the UE can use half of the TA value as the propagation delay. According to another embodiment of this disclosure, the TA command value information of the TA value can be included in the RAR message. In this case, the UE can derive the TA value from the TA command value.

[0052] According to embodiments of this disclosure, the accuracy or uncertainty value of the TA command value or propagation delay can be sent in the RAR message. The accuracy or uncertainty value may include time units or precise bits, indicating the accuracy of the transmitted TA value, TA command value, or propagation delay. Thereafter, the UE can apply the time information 1b-30 (1c-70) sent by the base station using the received propagation delay value. This propagation delay value can be used to correct the time information sent by the base station.

[0053] Because the propagation delay measured once may differ for a mobile UE, the UE may need to receive the propagation delay or TA value from the base station again. To achieve this, the UE can send a message requesting finer propagation delay (1c-30) or retransmit the RA preamble (1c-50) for propagation delay measurement. To adjust the aforementioned frequency, the UE can have a synchronization timer (1c-80). When receiving finer propagation delay information or a TA value, the UE can start or restart the synchronization timer (1c-80), and when the synchronization timer (1c-80) expires, the UE can send a message requesting finer propagation delay (1c-30) or retransmit the RA preamble (1c-50) for propagation delay measurement. The synchronization timer (1c-80) can have a duration shorter than or equal to that of the TA timer. The UE can also start or restart the TA timer when receiving finer TA or propagation delay values.

[0054] Figure 1d This is a diagram illustrating a method for allocating periodic RA preamble resources according to an embodiment of the present disclosure.

[0055] If the UE moves with mobility, propagation delay needs to be measured periodically. Therefore, forcing the UE to initiate RA (Rapid Alert) every time via a Physical DL Control Channel (PDCCH) command, or a contention-based RA, may be an inefficient configuration. To address this, RA channel (RACH) resources can be periodically allocated 1d-10, 1d-20, 1d-30, and 1d-40. The base station can configure the period 1d-50 during repeated RACH resource allocation, as well as the position or index of the RA preamble. By transmitting the RA preamble in each specific time period based on this configuration, the UE can receive finer-grained propagation delay, TA command value, or TA value.

[0056] In another embodiment of this disclosure, the base station may not need to configure RA resources for periodic measurement of propagation delay. That is, other physical resources, such as sounding reference signals (SRS), demodulation reference signals (DMRS), physical UL shared channel (PUSCH), physical UL control channel (PUCCH), etc., can be used. Even in this case, such as Figure 1d As shown, resources for time measurement can be allocated in cycles of 1d-50 to measure propagation delay. The UE can transmit UL signals on the resources, and the base station can measure the propagation delay and send the measured propagation delay to the UE.

[0057] Figure 1e This is a diagram illustrating a method for applying more refined timing information according to embodiments of the present disclosure.

[0058] In order to operate by connecting to URLLC services or TSN networks, the UE 1e-10 needs accurate time information to function within the communication system. This time information requires accuracy ranging from a few nanoseconds to hundreds of nanoseconds. If such accuracy cannot be guaranteed, the QoS requirements of URLLC services or TSN may not be met. Therefore, as... Figure 1b As shown, the base station can send more refined time information to the UE (1b-30). However, if the propagation delay between the base station and the UE is not properly compensated, the time information sent from the base station to the UE will have errors. Therefore, the UE needs to apply propagation time with a more refined level of accuracy by using propagation delay information with a more refined level of accuracy.

[0059] In some cases, the base station may have difficulty determining which UE requires more granular propagation delay information. Therefore, UE 1e-10 can send a message to base station 1e-20 indicating whether it requires more granular propagation delay information. In other words, the UE can request to receive a more granular propagation delay value from the base station (1e-30). The message requesting a more granular propagation delay value can include information indicating that the corresponding UE requires more granular propagation delay, as well as the accuracy value of the more granular propagation delay required by the UE. The message may also include the accuracy value of the propagation delay expected by the UE. In some cases, this accuracy value can be replaced by a value such as uncertainty.

[0060] Therefore, the base station may need to measure the propagation delay between the UE and the base station. The RA procedure can be used to perform the propagation delay measurement. The base station can allocate RA resources (1e-40) to the UE for propagation delay measurement. In related technologies, the base station can allocate RA resources to the UE, and the allocation of RA resources is to apply a TA value indicating the time at which the UE begins UL transmission to the base station. However, according to embodiments of this disclosure, the RA resources are intended to apply time information by compensating for propagation delay when applying time information sent by the base station to the UE, which may not be directly related to determining the start time of UL transmission by applying the TA value. Furthermore, the time information 1b-30 sent by the base station to the UE may need to have a finer degree of accuracy than the TA value. Therefore, the RA performed on the RA source for propagation delay measurement (i.e., the RA preamble 1e-50 sent for propagation delay measurement) may have a different accuracy than existing RA resources. For this purpose, RA resources with a high degree of accuracy in propagation delay measurement can be distinguished from existing RA resources. According to embodiments, this can be identified via RA preamble indexing, and RA preamble resources for specific index values ​​can be categorized and used as RA resources with a finer degree of accuracy. In some embodiments, index values ​​greater than (or greater than or equal to) a specific index value can be categorized and used as RA resources with a finer degree of accuracy. Therefore, for the purpose of measuring propagation delay or in cases where a finer degree of accuracy of RA is required, RA resources categorized as described above can be used to transmit RA preamble 1c-50. Base station 1e-20, which has already received the RA preamble on the categorized RA resources, can send a finer propagation delay value to UE (1e-60) in a TA command message. However, a TA value can be included in the RAR message instead of propagation delay information, and in this case, the UE can use half of the TA value as the propagation delay. According to another embodiment of this disclosure, TA command information can include the TA value. In this case, the UE can derive the TA value through the TA command.

[0061] According to embodiments of this disclosure, the accuracy or uncertainty value of the TA command value or propagation delay can be sent in the TA command message. The accuracy or uncertainty value may include time units or precise bits, indicating the accuracy of the transmitted TA value, TA command value, or propagation delay. Thereafter, the UE can apply the time information 1b-30 (1e-70) sent by the base station using the received propagation delay value. This propagation delay value can be used to correct the time information sent by the base station.

[0062] Because the propagation delay measured once may differ for a mobile UE, the UE may need to receive the propagation delay or TA value from the base station again. To achieve this, the UE can send a message to the base station requesting a more granular propagation delay (1e-30) or retransmit the RA preamble for propagation delay measurement (1e-50). To adjust the frequency of transmission or retransmission, the UE can have a synchronization timer 1e-80. When receiving more granular propagation delay information or a TA value, the UE can start or restart the synchronization timer 1e-80, and when the synchronization timer 1c-80 expires, the UE can send a message to the base station requesting a more granular propagation delay (1e-30) or retransmit the RA preamble (1e-50) for propagation delay measurement. The synchronization timer 1c-80 can have a duration shorter than or equal to that of the TA timer. The UE can also start or restart the TA timer when receiving a more granular TA value or propagation delay value.

[0063] Figure 1f This is a diagram illustrating the format of a RAR message.

[0064] In related technologies, when a UE sends an RA preamble, the base station can respond by sending a RAR message. The RAR message may include a TA command to allow the UE to adjust the TA value indicating the time at which the UE begins transmitting to the base station. Figure 1f In this context, we assume the TA command is a 12-bit value representing the TA command value. However, if a more granular TA value is required, the length of the TA command value may need to be changed. The base station can send UL clearance allocation information in the RAR message, enabling the UE that has already sent the RA preamble to send message 3 in subsequent RA operations. Based on this, the UE can send message 3. The Temporary Cell Radio Network Temporary Identifier (C-RNTI) value can also be included in the RAR message so that the UE can subsequently receive message 4. However, because such UL clearance allocation information or temporary C-RNTI is the primary configuration required by the UE performing initial access, these values ​​may not be necessary for UEs that require more granular TA values ​​or more granular propagation delay values.

[0065] Figure 1g This is a diagram illustrating the format of a RAR message according to an embodiment of this disclosure.

[0066] In related technologies, when a UE sends an RA preamble, the base station can respond by sending a RAR message. The RAR message can include a TA command to allow the UE to adjust the TA value indicating the time at which the UE begins transmitting to the base station. However, if a more precise TA value is required, the length of the TA command value may need to be changed. In this respect, a more refined TA command value can have a length greater than the traditional 12 bits of a TA command. This is... Figure 1g In English, this is referred to as the extended TA command. Although... Figure 1g An extended TA command with a length of 23 bits is shown, but this length only indicates that it is longer than the traditional TA command's 12 bits, and its exact length can vary depending on the situation. When the base station cannot support the accuracy of the TA command supported by the length of the extended TA command field, a separate field indicating the accuracy of the TA command actually supported by the base station is needed. This is in Figure 1g This is referred to as the uncertainty field. For example, if the extended TA command is expressed in units (multiples) of 10 ns, but the base station supports a propagation delay accuracy of 40 ns, then the uncertainty field can be set to a value corresponding to 40 ns. The value of this uncertainty field can be set to a multiple of the uncertainty value.

[0067] The base station can send UL grant allocation information in the RAR message, enabling a UE that has already sent the RA preamble to send message 3 in subsequent RA operations. Based on this, the UE can send message 3. The temporary C-RNTI value can also be included in the RAR message so that the UE can subsequently receive message 4. However, because such UL grant allocation information or temporary C-RNTI is the primary configuration required by the UE performing initial access, these values ​​may not be needed for UEs requiring more granular TA or propagation delay values. Therefore, in some cases, the RAR message sent to a UE requiring more granular TA or propagation delay values ​​may not include UL grant allocation information or temporary C-RNTI. Figure 1g The extended TA command field of a RAR message can be used in the same sense as sending a RAR message with a more granular TA value or propagation delay value.

[0068] Figure 1h This is a diagram illustrating the format of an extended TA command message according to an embodiment of this disclosure.

[0069] In related technologies, when a UE sends an RA preamble, the base station can respond by sending a TA command message to allow the UE to adjust the TA value indicating the time at which the UE begins transmitting to the base station. Such a TA command can be sent in the form of a Media Access Control (MAC) control element (CE). However, if a more granular TA value is required, the length of the TA command value in the TA command message may need to be changed. Furthermore, a more granular TA command value can have a longer length than the conventional 12 bits of a TA command. In embodiments of this disclosure, in Figure 1h In this context, more refined TA command values ​​with longer lengths are called extended TA commands. Although... Figure 1hAn extended TA command with a length of 23 bits is shown, but this length only indicates that it is greater than the 12 bits of a conventional TA command, and the exact length can be changed as needed. According to another embodiment of this disclosure, the extended TA command can indicate a finer relative value with respect to the currently applied TA value. When the extended TA command is received, the UE can start a synchronization timer.

[0070] Figure 1i This is a diagram illustrating the format of an extended TA command message according to an embodiment of this disclosure.

[0071] In related technologies, when a UE sends an RA preamble, the base station can respond by sending a TA command message, enabling the UE to adjust the TA value indicating the time at which the UE begins transmitting to the base station. Such a TA command can be sent in the form of a MAC CE. However, if a more granular TA value is required, the length of the TA command value in the TA command message may need to be changed. In this respect, a more granular TA command value can have a length greater than the 12 bits of a conventional TA command. In embodiments of this disclosure, in Figure 1i In this context, more refined TA command values ​​with longer lengths are called extended TA commands. Although... Figure 1i An extended TA command with a length of 23 bits is shown, but this length only indicates that it is longer than the traditional 12 bits of a TA command, and the exact length can be changed depending on the situation. When the base station cannot support the accuracy of the TA command supported by the length of the extended TA command field, a separate field indicating the accuracy of the TA command actually supported by the base station is needed. This is in Figure 1i This is referred to as the uncertainty field. For example, if the extended TA command is expressed in units (multiples) of 10 ns, but the accuracy of the propagation delay supported by the base station is 40 ns, then the uncertainty field can be set to a value corresponding to 40 ns. The value of this uncertainty field can be set to a multiple of the uncertainty value. In another embodiment of this disclosure, the extended TA command can indicate a finer relative value with respect to the currently applied TA value. When the extended TA command is received, the UE can start a synchronization timer.

[0072] Figure 1j This is a diagram illustrating the detailed operation of a synchronization timer according to an embodiment of the present disclosure.

[0073] When UE 1j-20 receives a finer TA value or propagation delay value from base station 1j-20 (1j-30, 1j-35), it can apply the propagation delay value (1j-30 and 1j-35). Due to UE movement or other error factors, such a finer TA value or propagation delay may only be valid information for a specific time period. To manage such valid time, UE 1j-10 can receive a finer TA value or propagation delay and start (1j-50) or restart (1j-55) a synchronization timer when applying the value. When the synchronization timer is running, this may mean that the UE is applying the current propagation delay as a valid value. Upon receiving an extended TA command value, the UE can also update the TA value, and in this case, start (1j-60) or restart (1j-65) a TA timer (TimingAdvanceTimer) that manages the validity period of the TA value.

[0074] Subsequently, when the synchronization timer expires, the UE can determine that the synchronization timer is no longer valid and send a message to the base station requesting a more refined TA value (1j-40). In another embodiment of this disclosure, instead of sending a message requesting a more refined TA value, the UE can send an RA preamble to the base station by triggering an RA procedure in which a more refined TA value can be measured.

[0075] Figure 1k This is a diagram illustrating a method for applying more refined time information according to an embodiment of the present disclosure.

[0076] In order to operate by connecting to URLLC services or TSN networks, the UE 1k-10 needs accurate time information for operation within the communication system. The time information required for the UE to operate by connecting to URLLC services or TSN networks needs to be accurate to the order of several nanoseconds to several hundred nanoseconds. If such accuracy cannot be guaranteed, the QoS requirements of URLLC services or TSN may not be met. Therefore, as... Figure 1b As shown, the base station can send more refined time information to the UE (1b-30). However, if the propagation delay between the base station and the UE is not properly compensated, the time information sent from the base station to the UE will have errors. Therefore, the UE needs to apply propagation time with a more refined degree of accuracy by using more refined propagation delay information.

[0077] In some cases, the base station may have difficulty determining which UE requires more granular propagation delay information. Therefore, UE 1k-10 can send a message to base station 1k-20 indicating whether it requires more granular propagation delay information. In other words, the UE can request a more granular propagation delay value from base station 1k-30. The propagation delay request message requesting a more granular propagation delay value may include information indicating that the corresponding UE requires more granular propagation delay, as well as the accuracy value of the more granular propagation delay required by the UE. The propagation delay request message may also include the accuracy value of the propagation delay expected by the UE. According to one embodiment, this accuracy value can be replaced by a value such as uncertainty. The propagation delay request message requesting a more granular propagation delay can be sent in the form of a UE Auxiliary Information Message or a MAC CE.

[0078] Subsequently, the base station can measure the propagation delay between the UE and the base station. To measure the propagation delay, the base station can allocate a portion of a specific physical channel to the UE (1k-40). In related technologies, the base station can allocate RA resources to the UE, and the allocation of RA resources is to apply a TA value indicating the time at which the UE begins UL transmission to the base station. However, according to embodiments of this disclosure, the RA resources are intended to apply time information by compensating for the propagation delay when applying the time information sent by the base station to the UE, which may not be directly related to determining the start time of UL transmission by applying the TA value. Furthermore, the time information 1b-30 sent by the base station to the UE may need to have a finer degree of accuracy than the TA value. Therefore, the time measurement signal 1k-50 for propagation delay measurement performed on radio resources used for physical delay measurement may have a different accuracy than existing RA resources. Such a time measurement signal can be one of SRS resources, DMRS resources, PUSCH resources, and PUCCH resources. The base station 1k-20, having received the time measurement signal, can send the propagation delay value to the UE (1k-60). Such a propagation delay value can be sent in the form of a MAC CE. In another embodiment of this disclosure, a more refined TA value may be included instead of propagation delay information, and in this case, the UE can use half of the TA value as the propagation delay. In another embodiment of this disclosure, when the TA value includes TA command value information, the UE can derive the TA value from the TA command value.

[0079] According to embodiments of this disclosure, the accuracy or uncertainty value of the propagation delay can be transmitted in the propagation delay message. The accuracy or uncertainty value may include a time unit or a number of precise bits indicating how accurate the propagation delay is. The UE can then apply the received propagation delay value to the time information 1b-30 (1k-70) transmitted by the base station. This propagation delay value can be used to correct the time information transmitted by the base station.

[0080] Because the propagation delay measured once may differ for a mobile UE, the UE may need to receive the propagation delay again from the base station. To achieve this, the UE can send a message requesting finer propagation delay (1k-30) or a retransmission time measurement signal for propagation delay measurement (1k-50) to the base station. To adjust the transmission or retransmission frequency, the UE can have a synchronization timer (1k-80). When finer propagation delay information is received, the UE can start or restart the synchronization timer, and when the synchronization timer expires, the UE can send a message requesting finer propagation delay (1k-30) or a retransmission time measurement signal for propagation delay measurement (1k-50) to the base station. The duration of the synchronization timer can be shorter than or equal to the TA timer. The UE can also start or restart the TA timer (not shown) when a propagation delay value is received.

[0081] Figure 11 This is a diagram illustrating the format of a propagation delay message according to an embodiment of the present disclosure.

[0082] In related technologies, the base station sends a propagation delay message to compensate for the propagation delay measured by the base station itself, or in response to a time measurement signal sent by the UE, allowing the UE to adjust the propagation delay. Such a propagation delay message can be sent in the form of MAC CE or DL ​​control information (DCI). Although Figure 11 The propagation delay is shown as 23 bits in length, but the exact length can vary depending on the situation. When the base station cannot support the accuracy of the propagation delay supported by the propagation delay message, a separate field indicating the accuracy of the propagation delay actually supported by the base station is required. This is in Figure 11 This is referred to as the uncertainty field. For example, if the propagation delay field included in the propagation delay message is expressed in units (multiples) of 10ns, but the base station supports a propagation delay accuracy of 40ns, then the uncertainty field can be set to a value corresponding to 40ns. The value of this uncertainty field can be set to a multiple of the uncertainty value. When a propagation delay message is received, the UE can start a synchronization timer.

[0083] Figure 1m A method for applying a more refined TA value according to embodiments of the present disclosure is shown.

[0084] Traditionally, TA values ​​obtained using RA or TA commands may not guarantee sufficient accuracy for use as finer-grained propagation delays for synchronization. To address this, the accuracy of TA values ​​can be improved by sending a relative TA value, 1m-20, which has a higher degree of accuracy than the existing TA value. A finer TA value, 1m-30, can be calculated by applying a relative TA value based on a previously set TA value. In this case, because the relative TA value 1m-20 is sent in a smaller time unit than the existing TA value 1m-10, the UE can calculate a finer propagation delay based on the calculated finer TA value 1m-30. In some cases, the propagation delay may be half that of the finer TA value.

[0085] Figure 1n A method for applying more refined propagation delay values ​​according to embodiments of the present disclosure is shown.

[0086] Traditionally, the TA value obtained using RA or TA commands may not guarantee sufficient accuracy for use as a finer propagation delay for synchronization. To address this, the accuracy of the propagation delay can be improved by sending a relative propagation delay 1n-20, which has higher accuracy than half of the existing TA value 1n-10 used as the propagation delay. In this case, a finer propagation delay value 1n-30 can be calculated by applying a relative propagation delay value based on half of the previously set TA value. Because the relative propagation delay 1n-20 is transmitted in a smaller time unit than half of the existing TA value 1n-10, the UE can calculate a finer propagation delay based on the calculated finer TA value 1n-30.

[0087] Figure 1o This is a diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0088] refer to Figure 1o UE 1o-40 may include a communication interface 1o-10, a processor 1o-20, and a memory 1o-30. However, UE 1o-40 is not limited to the above example and may include more than [the above example]. Figure 1o Show more or fewer components.

[0089] Communication interface 1o-10 can send signals to and receive signals from other network entities. For example, communication interface 1o-10 can receive system information, synchronization signals, or reference signals from a base station.

[0090] According to embodiments of this disclosure, processors 1o-20 can control all operations of the UE. For example, processors 1o-20 can control the signal flow between blocks, causing the UE to perform operations according to the flowchart described above.

[0091] The memory 1o-30 can store at least one of the information sent and received via the communication interface 1o-10 and the information generated via the processor 1o-20.

[0092] Figure 1p This is a diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0093] refer to Figure 1p Base station 1p-40 may include communication interface 1p-10, processor 1p-20, and memory 1p-30. However, base station 1p-40 is not limited to the above example and may include more than [the above example]. Figure 1p Show more or fewer components.

[0094] Communication interface 1p-10 can send signals to and receive signals from other network entities. For example, communication interface 1p-10 can send system information, synchronization signals, or reference signals to the UE.

[0095] According to the embodiments presented in this disclosure, processor 1p-20 can control all operations of the base station. For example, processor 1p-20 can control the signal flow between blocks, causing the base station to perform operations according to the flowchart described above.

[0096] The memory 1p-30 can store at least one of the information sent and received via the communication interface 1p-10 and the information generated by the processor 1p-20.

[0097] Figure 1q This is a diagram illustrating the format of a propagation delay message according to an embodiment of the present disclosure.

[0098] In related technologies, the base station sends a propagation delay message to compensate for the propagation delay measured by the base station itself, or in response to a time measurement signal sent by the UE, allowing the UE to adjust the propagation delay. Such a propagation delay message can be sent in the form of MAC CE or DCI. Furthermore, the propagation delay in the downlink and UL may differ.

[0099] In detail, Figure 1q An example is shown where, when a propagation delay is transmitted, the propagation delay message includes a D / U field indicating whether the propagation delay is for the DL or UL due to the different propagation delays in the DL and UL. In embodiments of this disclosure, depending on the value of the D / U field, this could mean that the value of the propagation delay field indicates the direction of the propagation delay time.

[0100] In another embodiment of this disclosure, the base station may send the propagation delays in UL and DL to the UE in a propagation delay message, without a separate D / U field. Although Figure 1qThe diagram shows a propagation delay with a length of 23 bits, but its exact length can vary depending on the situation. When the base station cannot support the accuracy of the propagation delay supported by the propagation delay message, a separate field indicating the accuracy of the propagation delay actually supported by the base station is required. This is in Figure 1q This is referred to as the uncertainty field. For example, if the propagation delay field included in a propagation delay message is expressed in units (multiples) of 10 ns, but the base station supports a propagation delay accuracy of 40 ns, then the uncertainty field can be set to a value corresponding to 40 ns. The value of this uncertainty field can be set to a multiple of the uncertainty value.

[0101] According to embodiments of this disclosure, the UE can start a synchronization timer upon receiving a propagation delay message. As described above, when the propagation delays in the DL and UL are different from each other, the synchronization timer can have independent synchronization timers for the DL and UL, or operate only for the UL.

[0102] Figure 1r It is a diagram used to describe the time difference that occurs between base stations at a reference time point.

[0103] refer to Figure 1r In a dual-connectivity architecture, a UE can connect to one base station or two base stations. Furthermore, even though a UE is connected to a serving base station, it can perform handover to other base stations. Base stations 1r-10 and 1r-50 can be physically installed in different locations, and when base stations are installed in different locations, it is understood that the local operating time of each base station can be different. Additionally, base stations 1r-10 and 1r-50 can operate multiple cells 1r-20, 1r-30, 1r-60, and 1r-70, and these cells can be classified as PCells 1r-20 and 1r-60, secondary cells (SCells) 1r-30 and 1r-70, PSCell (not shown), etc.

[0104] Within each base station 1r-10 and 1r-50, the actual operation time of each cell may differ due to factors such as module location limitations. Therefore, the start or end time of frames or symbols for each cell may vary. Furthermore, errors may occur due to the propagation time incurred when each cell transmits data to the UE. Figure 1rIn this context, because the communication paths 1r-25 between PCell 1r-20 and the UE of base station 1 1r-10, 1r-35 between SCell 1r-30 and the UE of base station 1 1r-10, 1r-65 between PCell 1r-60 and the UE of base station 2 1r-50, and 1r-75 between SCell 1r-70 of base station 2 are different, propagation time differences may occur. These propagation time differences, i.e., differences in operation time between base stations and between cells, may not have a significant impact on transmission and reception, but they will affect the processing of URLLC services or TSN protocols. Therefore, it is necessary to reduce the error caused by time differences and to specify a separate reference. Figure 1b The time information described refers to the base station and cell information.

[0105] In some cases, the serving base station can notify the target base station of its time information before a handover occurs. For example, when a UE connected to base station 1 performs a handover to base station 2, or when a UE connected to both base stations 1 and 2 needs to update its time information using the reference time of base station 2, base station 1 can send the reference time information of base station 2 to the UE, where base station 2 is the base station applying the new reference time. Such time information from other base stations can be included in the reference time. Figure 1b The time information message described is in message 1b-30, or it may be sent in time information messages from other base stations (e.g., 1s-50), as will be discussed later. Figure 1s As described, the base station can send time information, allowing the UE to identify it as time information from other base stations.

[0106] According to embodiments of this disclosure, time information from other base stations can be sent to the UE. This time information also includes information for measuring propagation delay at the other base stations. Information for propagation delay measurement at other base stations can be sent, including information about physical channels that can be used for propagation delay measurement at other base stations (or another cell) or the target base station to which the UE is to be handed over. For example, physical channels that can be used for propagation delay measurement may be Physical RACH (PRACH), PUCCH, SRS, etc. When it is necessary to measure the UE's DL propagation delay, physical channels that can be used for propagation delay measurement may be PDCCH, Physical DL Shared Channel (PDSCH), DMRS, Synchronization Signal Block (SSB), etc.

[0107] Figure 1s This is a diagram illustrating a process for transmitting time information from other base stations according to an embodiment of the present disclosure.

[0108] exist Figure 1sAssume UE 1s-10 is connected to base station 1 1s-20 and can receive time information from base station 1 1s-20. However, for dual connectivity or handover purposes, it is expected that UE 1s-10 will connect to base station 2 1s-30. In this case, UE 1s-10 can receive time information from base station 2 1s-30 to prepare for handling URLLC services or TSN protocol operations via the connection to base station 2 1s-30. Therefore, base station 1 1s-20 can send a time information request 1s-35 to base station 2 1s-30.

[0109] The time information request 1s-35 can be sent in the handover request message during the handover preparation process. Subsequently, base station 2 1s-30 can send the time information used by base station 2 1s-30 (1s-40) to base station 1 1s-20. In addition, base station 2 1s-30 can notify base station 1 1s-20 of the reference time used by base station 2 1s-30 and the cell whose reference time is used by base station 2 1s-30.

[0110] In embodiments of this disclosure, base station 1 1s-20 may send a message to the UE including time information of base station 2 1s-30 received from base station 2 1s-30 (1s-50). This message may include information indicating the cell of the base station whose time information corresponds to it. In other words, the message may include a Physical Cell Identifier (PCI). In another embodiment of this disclosure, the time information sent from base station 2 1s-30 to base station 1 1s-20 may be sent to UE 1s-10 in the same manner. When receiving time information from other base stations, UE 1s-10 may update the corresponding value to apply the time information immediately (1s-60) or apply the time information (1s-60) after accessing the corresponding base station.

[0111] When a UE is preparing to hand over to or performing a handover to a corresponding base station, time information from other base stations can be sent to the UE from those base stations. For example, if the Information Element (IE) of the serving base station's time information is TimingReferenceInfo, the time information of the target base station can be referred to as TimingReferenceInfoTarget, and in this case, the IE can include the time information of the base station to which the UE intends to hand over. The target base station's time information can be sent in a Radio Resource Control (RRC) reconfiguration message that includes mobility control information, a reconfiguration message with synchronization, or a handover command message used as a handover message.

[0112] In embodiments of this disclosure, timing information from other base stations can be transmitted as system information. For example, each TimingReferenceInfo IE can be categorized by PCI or base station ID to transmit timing information from one or more other base stations. Furthermore, timing information from other base stations, including information for propagation delay measurement at other base stations, can be transmitted to the UE. For example, the information for propagation delay measurement may include information about physical channels that can be used for propagation delay measurement at other base stations (or another cell) or the target base station to which the UE is to be handed over. Physical channels that can be used for propagation delay measurement may be PRACH, PUCCH, SRS, etc. When it is necessary to measure the UE's DL propagation delay, physical channels that can be used for propagation delay measurement may be PDCCH, PDSCH, DMRS, SSB, etc. By using this information, the UE can measure and compensate for propagation delay after handover or at other base stations 1s-30. In another embodiment of this disclosure, other base stations 1k-10 may have to transmit timing measurement signals 1k-50 to the UE 1k-10. In UL, the UE can apply the timing information of the new base station after obtaining the propagation delay information.

[0113] Figure 2a This is a diagram illustrating the operation of the configuration configuration license (CG) and hybrid automatic repeat request (HARQ) process according to an embodiment of this disclosure.

[0114] Figure 2aCGs 2a-10, 2a-20, 2a-30, 2a-40, and 2a-50 are configured to have a specific period 2a-05 on the time axis 2a-60. According to embodiments of this disclosure, the base station can configure each CG for the UE and configure the period, location and size, modulation, coding rate, etc., of the radio resources. Such CGs can be configured in both licensed and unlicensed spectrum. In some cases, such CGs can be activated immediately upon configuration or can be activated by a separate activation command. A wireless communication system can have CGs that are activated immediately upon configuration without a separate process, and such CGs can be referred to as CG type 1. On the other hand, a wireless communication system can have CGs activated by a separate signal such as DCI, and such CGs can be referred to as CG type 2. The activation message for CG type 2 can include at least one of detailed resource location or modulation and coding scheme (MCS) information. It can be assumed that CGs have a fixed service mode or are used for high-priority data. In certain cases, CGs can be dedicated to data with short latency requirements. To meet short latency requirements, the base station can configure whether a specific radio resource (CG) can be used for each specific logical channel via RRC configuration messages. In some cases, the UE can be configured with multiple CGs, and in this case, the period, radio resource location and size, modulation, coding rate, etc., of each CG can be configured differently.

[0115] In embodiments of this disclosure, one or more HARQ processes can be used for CG. Available HARQ processes can be configured by the base station according to the configuration of CG resources. The HARQ process used for CG can be determined by the number of available HARQ processes and the HARQ process ID offset. Specifically, a HARQ process with a HARQ process ID (or HPI) can be used for CG, the value of which ranges from the HARQ process ID offset value to a value corresponding to (HARQ process ID offset) + (number of available HARQ processes) - 1. Figure 2a In this scenario, assuming the HARQ process ID offset is set to 0 and the number of available HARQ processes is set to 2, two HARQ processes with HARQ process ID values ​​ranging from 0 to 1 are used alternately for CG.

[0116] In another embodiment of this disclosure, when configuring a CG in unlicensed spectrum, the method for determining such a HARQ process ID can be applied differently. In unlicensed spectrum, because the UE sends a CG including HAQR process ID (or HPI) information to the base station during CG transmission, the value of the HARQ process ID may not be used interchangeably. In this case, the UE can determine the HPI based on whether data exists in the HARQ buffer of the HARQ process, use it for CG transmission, and transmit the CG including the value of the HARQ process ID to the base station.

[0117] Figure 2b A method for performing retransmission on a CG in an unlicensed spectrum is illustrated according to an embodiment of the present disclosure.

[0118] Unlicensed spectrum can be shared with other communication systems. Therefore, in order to use unlicensed spectrum, it is necessary to perform a Listen-Before-Talk (LBT) process to check whether the unlicensed spectrum is in use and to only perform communication if it is available. Transmissions using UL-licensed spectrum are determined during the LBT process and then executed during the actual transmission. Thus, a series of operations, such as generating MAC Protocol Data Units (PDUs) for UL transmissions, can be completed before the LBT is determined to have failed.

[0119] When CG 2b-10 is configured in unlicensed spectrum and the UE determines to transmit on CG 2b-10, CG 2b-10 may fail to transmit successfully due to LBT failure. When LBT failure 2b-30 occurs during the time including the transmission on CG 2b-10, retransmission on CG 2b-10 may be required. However, during the period when LBT failure 2b-30 remains valid, retransmission on the corresponding CG will not occur. As mentioned above, when LBT failure 2b-30 occurs, a MAC PDU to be transmitted on CG 2b-10 may have already been generated. Therefore, a MAC PDU needs to be transmitted. However, it is difficult for the base station to know whether the UE has already generated a MAC PDU to be transmitted on CG 2b-10. Furthermore, due to the LBT failure, the retransmission resources sent by the base station may not be delivered to the UE. Therefore, in unlicensed spectrum, the UE can autonomously perform the operation of retransmitting the generated MAC PDU on the next CG resource 2b-40.

[0120] In another embodiment of this disclosure, after a transmission is not performed on a CG due to an LBT failure or other transmission failure, the UE can perform a retransmission using a dynamic license allocated by the base station via a configured scheduling RNTI (CS-RNTI). To indicate the time when the base station allocates retransmission resources, the UE can start a CG-Retransmission Timer 2b-20 at the time the UE indicates the time for CG transmission to the lower layer. In certain cases, CG-Retransmission Timer 2b-20 can be started only if an LBT failure does not occur. Furthermore, after the CG-Retransmission Timer 2b-20 expires, a retransmission on CG 2b-10, which was not performed due to an LBT failure or other transmission failure, can be performed on the next CG resource 2b-40. At this time, the UE can set the HARQ process ID of the CG to the HARQ process ID of the CG resource 2b-10 that failed to be transmitted due to an LBT failure, and use the HARQ process ID to notify the base station to transmit.

[0121] Figure 2c An embodiment of the present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum.

[0122] Data used for URLLC services has low latency requirements, and to meet these requirements, more resources can be allocated than are actually needed for the generated data. Because a larger amount of radio resources are allocated than the actual generated data requires, some resources may be allocated to overlap with other resources on the time axis (or time and frequency axis), but this may not significantly increase latency.

[0123] In embodiments of this disclosure, in Figure 2c It is assumed that CG 2c-10 overlaps with another UL resource 2c-20 on the time axis. When UL resource 2c-20 is a UL license sent on the PUSCH (meaning a UL resource allocated using a UL license and sent on the PUSCH; this also applies below), UL resource 2c-20 can overlap with CG 2c-10 within the same bandwidth portion (BWP) on the time axis. When UL resource 2c-20 is a scheduling request (SR) resource sent on the PUCCH, UL resource 2c-20 can overlap with CG 2c-10 within the same MAC entity on the time axis.

[0124] In embodiments of this disclosure, when two UL resources overlap, the resource with the higher priority (i.e., the lower priority value) can be prioritized and actually transmitted. Conversely, the non-prioritized UL resource can be a de-prioritized resource. In this case, the priority of the UL license transmitted on the PUSCH can be determined by the highest priority among the logical channels that can be transmitted using UL resources 2c-20. The priority of the SR resource transmitted on the PUCCH can be determined by the priority of the logical channel that triggered the SR request message.

[0125] exist Figure 2c In this scenario, assume that CG resource 2c-10 overlaps with another resource 2c-20 on the timeline, and that other resources have higher priority than CG, with 2c-20 being either a prioritized UL license or a prioritized SR transmission. In this case, CG 2c-10 configured in unlicensed spectrum is a de-prioritized UL license. As mentioned above, when CG resource 2c-10 is a de-prioritized UL license, this means no actual transmission is performed, and therefore, CG retransmission timer 2c-30 does not need to be started. Therefore, when the CG resource is a de-prioritized UL license in an unlicensed band, CG retransmission timer 2c-30 may not start. Because CG retransmission timer 2c-30 is not started, the UE can immediately perform a retransmission using CG 2c-10 when a valid UL transmission occurs later.

[0126] Figure 2d An embodiment of the present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum.

[0127] Data used for URLLC services has low latency requirements, and to meet these requirements, more resources can be allocated than are actually needed for the generated data. Because a larger amount of radio resources are allocated than the actual generated data requires, some resources may be allocated to overlap with other resources on the time axis (or time and frequency axis), but this may not significantly increase latency.

[0128] In embodiments of this disclosure, in Figure 2d It is assumed that CG 2d-10 overlaps with SR resource 2d-40 on another cell in the timeline. When two UL resources overlap, the resource with the higher priority (i.e., the lower priority value) can be prioritized and actually transmitted. On the other hand, the non-prioritized UL resource can be de-prioritized. The priority of the UL grant, including CG, transmitted on the PUSCH can be determined by the highest priority among the logical channels that can be used to transmit with the UL grant. The priority of the SR resource transmitted on the PUCCH can be determined by the priority of the logical channel that triggers the SR request message.

[0129] According to embodiments of this disclosure, in Figure 2d The following assumes that CG 2d-10 is configured in unlicensed spectrum, but LBT failure 2d-30 occurs during the transmission attempt. In this case, CG 2d-10 may not actually be transmitted. If the CG resource is a prioritized UL license, another UL resource overlapping with the CG resource on the timeline within the same BWP is a de-prioritized UL license, and the SR transmission resource 2b-40 overlapping it on the timeline within the same MAC entity is a de-prioritized SR transmission. However, because the LBT failure occurs in unlicensed spectrum where the prioritized UL license occurs, CG 2d-10 cannot be transmitted.

[0130] In this situation, a problem arises where, although SR transmission is permitted, it is not performed because SR transmission is de-prioritized due to CG. Therefore, according to embodiments of this disclosure, when an LBT failure indication is received, the CG resource that failed to be transmitted as a result of the LBT process needs to be de-prioritized with UL permission. Since the CG resource is de-prioritized with UL permission, the SR transmission resource is prioritized for SR transmission, thus enabling transmission. In other words, this solves the problem that even if SR transmission is possible, it is not performed because SR transmission is de-prioritized due to CG.

[0131] exist Figure 2d In this paper, only LBT failures transmitted on CG resources are considered. However, according to another embodiment of this disclosure, if an LBT failure indicates a dynamically licensed resource, the CG resource can be a de-prioritized UL license. Therefore, when determining whether an SR transmission on an SR transmission resource is prioritized, the resource on the BWP (or cell) indicating an LBT failure can be excluded from the prioritization operation, even if the resource overlaps on the time axis. That is, if i) there is no LBT failure indicating an SR transmission, ii) if the SR transmission is not a de-prioritized UL license (or SR transmission), and iii) if there is no UL license (SR transmission) with higher priority among the overlapping UL licenses and SR transmissions on the time axis, the corresponding SR transmission can be determined as a prioritized SR transmission.

[0132] Figure 2e An embodiment of the present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum.

[0133] Fifth-generation (5G) communication UEs can simultaneously utilize cells in both licensed and unlicensed spectrum using carrier aggregation (CA) technology. When using CA, even if an LBT failure occurs on a cell in the unlicensed spectrum (2e-10), transmission can continue on another cell where the LBT failure did not occur. To this end, when an LBT failure occurs, the UE can cancel transmissions on the UL license in the time domain indicating the LBT failure (2e-20). Canceling transmissions on the UL license can be understood as cancelling the transmission of a MAC PDU that would have used the UL license in the time domain indicating the LBT failure (i.e., the UL license indicating the LBT failure). Furthermore, cancelling MAC PDU transmissions may mean that the MAC Service Data Unit (MAC SDU) and MAC CE included in the MAC PDU are included in another MAC PDU and transmitted. In other cases, the UL license in the time domain indicating the LBT failure can be used in the same sense as the MAC PDU in the buffer associated with the HARQ process ID of the UL license in the time domain indicating the LBT failure. A UL license in the time domain indicating LBT failure can be considered a de-prioritized UL license. In some cases, a UL license in the time domain indicating LBT failure can be identified as a de-prioritized UL license (2e-30).

[0134] Figure 2f An embodiment of the present disclosure illustrates a logical channel-based prioritization operation in unlicensed spectrum.

[0135] 5G communication UEs can utilize cells in both licensed and unlicensed spectrum simultaneously using carrier aggregation (CA) technology. When using CA, even if a Level Transmission Bypass (LBT) failure occurs on a cell in the unlicensed spectrum, transmission can continue on another cell where the LBT failure did not occur. However, when generating MAC PDUs for transmission on the cell where the LBT failure occurred, the MAC PDU data is difficult to transmit on the other cell. Furthermore, when there is a prioritized UL license on a cell, the scheduling request transmission on another cell becomes a de-prioritized scheduling request and cannot be transmitted. Therefore, when an LBT failure occurs, the corresponding UL license and the MAC PDU transmitted on the corresponding UL license need to be de-prioritized.

[0136] When the base station allocates UL license 2f-10 to the UE, the UE needs to determine when to prioritize UL license 2f-10. In this case, UL license 2f-10 can be prioritized as UL license 2f-20. Unless there are special circumstances, actual transmission needs to be performed on UL license 2f-20, but LBT failure may occur on unlicensed spectrum. LBT failure 2f-30 means that UL license 2f-20 cannot be transmitted. In this case, UL license 2f-20 can be changed back to de-prioritized UL license 2f-40. Changing back to de-prioritized UL license in this way allows SR messages transmitted on another cell to be transmitted.

[0137] Figure 2g The following describes the operation process when the LBT fails in unlicensed spectrum, according to an embodiment of the present disclosure.

[0138] UL licenses can be sent in units of transport blocks, and each transport block corresponds to a MAC PDU on a one-to-one basis. In other words, UL licenses can be used to send MAC PDUs. MAC PDUs can be sent, which include MAC SDUs 2g-20 and 2g-40 representing logical channel data and MAC CEs 2g-60 representing MAC layer control information. MAC SDUs and MAC CEs can include MAC subheaders 2g-10, 2g-30, and 2g-50 immediately preceding them, respectively. Therefore, the MAC subheaders can indicate what type of information the subsequent MAC SDU or MAC CE is. MAC CEs are information used at the MAC layer, but MAC SDUs are information formed and received from the Radio Link Control (RLC) layer, which is the upper layer, and are identical to RLC PDUs 2g-25 and 2g-45.

[0139] When a MAC PDU is generated and stored in a HARQ buffer, the RLC layer will not deliver the same RLC PDU to the MAC layer unless an instruction such as a retransmission indication is received. However, if an RLC PDU (MAC SDU) delivered to the MAC layer and included in the MAC PDU is not sent by the MAC layer due to LBT failure, the MAC SDU cannot be sent until the LBT succeeds and the data is sent, which may cause transmission delays. Therefore, when the LBT fails for the UL clearance used to send the MAC PDU, the MAC SDU included in the MAC PDU needs to be retransmitted by the RLC layer. In other words, the MAC SDU (RLC PDU) needs to be multiplexed and sent on another UL clearance. For example, when the LBT fails for the UL clearance used to send the MAC PDU, the RLC SDU can be retransmitted by the RLC layer instead of the RLC PDU, or the MACSDU included in the MAC PDU can be delivered to the RLC layer or, as an upper-layer Packet Data Convergence Protocol (PDCP) layer, so that they are retransmitted. In this context, transmission at the RLC layer can be understood as sending (submitting) data (RLC SDU or RLCPDU) to the lower MAC layer.

[0140] Figure 2h This is a diagram illustrating the structure of a UE according to an embodiment of the present disclosure.

[0141] refer to Figure 2h The UE 2h-40 may include a communication interface 2h-10, a processor 2h-20, and a memory 2h-30.

[0142] The communication interface 2h-10 can send signals to and receive signals from other network entities. For example, the communication interface 2h-10 can receive system information, synchronization signals, or reference signals from a base station.

[0143] According to the embodiments presented in this disclosure, processors 2h-20 can control all operations of the UE. For example, processors 2h-20 can control the signal flow between blocks, causing the UE to perform operations according to the flowchart described above.

[0144] The memory 2h-30 can store at least one of the information sent and received via the communication interface 2h-10 and the information generated via the processor 2h-20.

[0145] Figure 2i This is a diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0146] refer to Figure 2i The base station 2i-40 may include a communication interface 2i-10, a processor 2i-20, and a memory 2i-30.

[0147] Communication interface 2i-10 can send signals to and receive signals from other network entities. For example, communication interface 2i-10 can send system information, synchronization signals, or reference signals to the UE.

[0148] According to the embodiments presented in this disclosure, processors 21-20 can control all operations of the base station. For example, processors 21-20 can control the signal flow between blocks, causing the base station to perform operations according to the flowchart described above.

[0149] The memory 2i-30 can store at least one of the information sent and received via the communication interface 2i-10 and the information generated via the processor 2i-20.

[0150] Machine-readable storage media can be provided in the form of non-transitory storage media. In this respect, the term "non-transitory" simply means that the storage medium does not include signals and is a tangible device, and the term does not distinguish between where data is stored semi-permanently in the storage medium and where data is temporarily stored in the storage medium. For example, "non-transitory storage media" may include buffers for temporarily storing data.

[0151] According to one embodiment, when provided, methods according to the various embodiments set forth herein may be included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. For example, the computer program product may be distributed in the form of a machine-readable storage medium (e.g., an optical disc read-only memory (CD-ROM)), or distributed online (e.g., downloaded or uploaded) via an app store (e.g., Google Play Store™), or distributed directly between two user devices (e.g., smartphones). For online distribution, at least a portion of the computer program product (e.g., a downloadable application) may be at least temporarily stored or temporarily created on a machine-readable storage medium, such as the memory of a manufacturer's server, an app store's server, or a relay server.

Claims

1. A method performed by a user equipment (UE), the method comprising: performing listen before talk (LBT) on a configured grant (CG) resource in an unlicensed spectrum; identifying a failure of the LBT on the CG resource; in a case that the CG resource overlaps with other uplink (UL) resources on a time axis and the CG resource is configured as a prioritized resource, determining the other UL resources as the prioritized resources and the CG resource as a deprioritized resource based on the failure of the LBT; and performing UL transmission using the other UL resources configured as the prioritized resources.

2. The method of claim 1, wherein, performing the UL transmission comprises: transmitting a scheduling request (SR) on the other UL resources configured as the prioritized resources.

3. The method of claim 2, wherein, in a case that the CG resource is configured on a first cell and the other UL resources are configured on a second cell, the SR is transmitted on the second cell.

4. The method of claim 1, wherein, performing the UL transmission comprises: in a case that the CG resource is configured on a first cell and the other UL resources are configured on a second cell, cancelling transmission of a medium access control (MAC) service data unit (SDU) and a MAC control element (CE) included in a first MAC protocol data unit (PDU) on the CG resource; generating a second MAC PDU including the MAC SDU and the MAC CE; and transmitting the second MAC PDU using the other UL resources configured on the second cell.

5. The method of claim 1, wherein, performing the UL transmission comprises: transmitting a MAC SDU included in a MAC PDU for the CG resource to a radio link control (RLC) layer or a packet data convergence protocol (PDCP) layer.

6. The method of claim 1, further comprising: identifying a failure of the LBT on a dynamic grant resource; and in a case that the dynamic grant resource overlaps with other UL resources on a time axis and the dynamic grant resource is configured as a prioritized resource, determining the other UL resources as the prioritized resources and the dynamic grant resource as a deprioritized resource based on the failure of the LBT on the dynamic grant resource.

7. A user equipment (UE), comprising: a transceiver; and at least one processor coupled with the transceiver and configured to: perform listen before talk (LBT) on a configured grant (CG) resource in an unlicensed spectrum; identify a failure of the LBT on the CG resource; in a case that the CG resource overlaps with other uplink (UL) resources on a time axis and the CG resource is configured as a prioritized resource, determine the other UL resources as the prioritized resources and the CG resource as a deprioritized resource based on the failure of the LBT; and perform UL transmission using the other UL resources configured as the prioritized resources. the at least one processor is configured to: transmit a scheduling request (SR) on the other UL resources configured as the prioritized resources.

8. The UE of claim 7, wherein, in a case that the CG resource is configured on a first cell and the other UL resources are configured on a second cell, the SR is transmitted on the second cell. the at least one processor is configured to:

9. The UE of claim 8, wherein, ​ 10. The UE of claim 7, wherein, ​ In a case where the CG resource is configured on the first cell and the other UL resource is configured on the second cell, canceling transmission of a medium access control (MAC) service data unit (SDU) and a MAC control element (CE) included in a first MAC protocol data unit (PDU) on the CG resource; generating a second MAC PDU including the MAC SDU and the MAC CE; and transmitting the second MAC PDU using the other UL resource configured on the second cell.

11. The UE of claim 7, wherein, The at least one processor is configured to: transmit a MAC SDU included in a MAC PDU for the CG resource to a radio link control (RLC) layer or a packet data convergence protocol (PDCP) layer.

12. The UE of claim 7, wherein, The at least one processor is configured to: identify an LBT failure of a dynamic grant resource; and in a case where the dynamic grant resource overlaps with the other UL resource on a time axis and the dynamic grant resource is configured as a prioritized resource, based on the LBT failure of the dynamic grant resource, determine the other UL resource as a prioritized resource and the dynamic grant resource as a de-prioritized resource.

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