KR102691816B1 - Method for providing multicast service and unicast service in a wireless communication system and apparatus therefor - Google Patents

Abstract

The present invention relates to a method for transmitting data from a base station to a terminal, the method comprising: transmitting the data to the terminal in a multicast manner; Receiving a multicast transmission failure report from the terminal; And transmitting the data to the terminal in a unicast manner, wherein the failure report includes a failure report transmission point of the terminal, a failure report transmission location of the terminal, and wireless quality information at the time of the terminal's failure report. Characterized by including at least one.

Description

Method for providing multicast service and unicast service in a wireless communication system and apparatus therefor}

The present invention relates to a wireless communication system, and more specifically, to a method and device for providing multicast service and unicast service in a wireless communication system.

With the introduction of new wireless communication technology, not only does the number of UEs that the base station must provide service to in a given resource area increase, but also the amount of data and control information transmitted/received by the base station to and from the UEs it provides service with increases. It is increasing. Since the amount of radio resources available to the base station for communication with the UE(s) is limited, the base station uses the finite radio resources to transmit uplink/downlink data and/or uplink/downlink control information from/to the UE(s). A new method for efficient reception/transmission is required. In particular, applications whose performance is significantly influenced by delay/delay are increasing. Therefore, a method to reduce delays/delays compared to existing systems is required.

The purpose of the present invention is to provide a method and device for providing multicast service and unicast service in a wireless communication system.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

A method of transmitting data from a base station to a terminal, which is an aspect of the present invention, includes transmitting the data to the terminal in a multicast manner; Receiving a multicast transmission failure report from the terminal; And transmitting the data to the terminal in a unicast manner, wherein the failure report includes a failure report transmission point of the terminal, a failure report transmission location of the terminal, and wireless quality information at the time of the terminal's failure report. Characterized by including at least one.

Preferably, the step of transmitting the data in the multicast method includes calculating a first average value of the MCS level provided to the terminal in the multicast method for a first time, and the unicast method The step of transmitting the data may include calculating a second average value of the MCS level provided to the terminal through the unicast method for a second time. More preferably, the method may further include storing a failure report received from the terminal together with the first average value and the second average value.

Preferably, transmitting the data in the unicast method may include transmitting an indicator indicating a change from the multicast method to the unicast method.

Preferably, when reporting a failure of the terminal, the wireless quality information includes at least one of RSRP (Reference Signal Received Power), SNR (signal-to-noise ratio), and RSSI (Received Signal Strength Indicator). . Preferably, the failure report is received from the terminal when the terminal moves outside the coverage of the multicast method.

Meanwhile, a method for a terminal to receive data from a base station, which is an aspect of the present invention, includes receiving the data from the base station in a multicast manner; When moving outside of the multicast coverage, transmitting a report of failure of multicast transmission to the base station; and receiving the data from the base station in a unicast manner, wherein the failure report is at least one of a transmission point of the failure report, a transmission location of the failure report, and radio quality information at the time of constant failure report transmission. It is characterized by including.

Preferably, the base station calculates a first average value of the MCS level provided to the terminal through the multicast method during a first time, and calculates a first average value of the MCS level provided to the terminal through the unicast method during a second time. Calculate the second average value. More preferably, the base station stores the failure report received from the terminal together with the first average value and the second average value.

Preferably, the step of receiving the data in the unicast manner may include the step of receiving an indicator notifying a change from the multicast manner to the unicast manner.

Preferably, the radio quality information may include at least one of RSRP, SNR, and RSSI, and the step of transmitting the failure report includes transmitting the failure report when the terminal moves outside the coverage of the multicast method. It is characterized by including the step of:

Meanwhile, a base station device, which is an aspect of the present invention, includes a wireless communication module; Memory; and a processor, wherein the processor transmits the data in a multicast manner to a terminal, receives a failure report of multicast transmission from the terminal, and causes the base station to transmit the data in a unicast manner to the terminal. The device is controlled, and the failure report includes at least one of a failure report transmission point of the terminal, a failure report transmission location of the terminal, and radio quality information at the time of the terminal's failure report.

Preferably, the processor calculates a first average value of the MCS level provided to the terminal through the multicast method for a first time, and calculates a first average value of the MCS level provided to the terminal through the unicast method during a second time. A second average value can be calculated. More preferably, the processor stores the failure report received from the terminal in the memory along with the first average value and the second average value.

Preferably, when transmitting the data in the unicast method, the processor may transmit an indicator indicating a change from the multicast method to the unicast method, and provide wireless quality information when the terminal reports a failure. is characterized in that it includes at least one of RSRP, SNR, and RSSI. Preferably, the failure report is received from the terminal when the terminal moves outside the coverage of the multicast method.

Finally, storing at least one computer program that, when executed by at least one processor, which is an aspect of the present invention, includes instructions that cause the at least one processor to perform operations for the base station to transmit data to the terminal. A non-volatile computer-readable storage medium is proposed. In particular, the operations include transmitting the data to the terminal in a multicast manner; Receiving a multicast transmission failure report from the terminal; And transmitting the data to the terminal in a unicast manner, wherein the failure report includes a failure report transmission point of the terminal, a failure report transmission location of the terminal, and wireless quality information at the time of the terminal's failure report. Characterized by including at least one.

Preferably, the step of transmitting the data in the multicast method among the operations includes calculating a first average value of the MCS level provided to the terminal in the multicast method for a first time, Among the operations, the step of transmitting the data in the unicast method includes calculating a second average value of the MCS level provided to the terminal in the unicast method for a second time. More preferably, the method may further include storing a failure report received from the terminal together with the first average value and the second average value.

Similarly, among the operations, transmitting the data in the unicast method may include transmitting an indicator indicating a change from the multicast method to the unicast method. Also, preferably, when reporting a failure of the terminal, the radio quality information may include at least one of RSRP, SNR, and RSSI, and the failure report is reported when the terminal moves outside the coverage of the multicast method. It is characterized in that it is received from the terminal.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The present invention provides a method and device for providing multicast service and unicast service in a wireless communication system.

In addition, according to the method and device for providing multicast service and unicast service in a wireless communication system of the present invention, in a next-generation wireless communication system such as a 5G system, a terminal has a change point between multicast service and unicast service, Reports on change locations and quality indicators can be provided to the base station.

In addition, according to the method and device for providing multicast service and unicast service in a wireless communication system of the present invention, the quality of broadcast service is improved through procedures such as machine learning or automatic parameter change based on the above-described report. You can do it.

In addition, various effects that can be directly or indirectly identified through this document may be provided.

The drawings attached to this specification are intended to provide an understanding of the present invention, show various embodiments of the present invention, and together with the description of the specification, explain the principles of the present invention.
1 is an example of a network of a communication system.
2 is a block diagram illustrating examples of communication devices capable of performing methods according to the present disclosure.
3 illustrates operations of wireless devices based on implementations of the present specification.
Figure 4 illustrates a structural diagram of MAC channel mapping and physical channel mapping when transmitting MBS data in a 5G system to which the present invention can be applied.
Figure 5 shows an example of reporting a multicast transmission failure according to an embodiment of the present invention.
Figure 6 shows an example of performing unicast transmission according to an embodiment of the present invention.
Figure 7 illustrates a multicast transmission failure report stored in a base station according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through illustrative drawings. When adding reference numerals to components in each drawing, it should be noted that identical components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, when describing embodiments of the present invention, if detailed descriptions of related known configurations or functions are judged to impede understanding of the embodiments of the present invention, the detailed descriptions will be omitted.

In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. Additionally, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as having an ideal or excessively formal meaning unless explicitly defined in the present application. No.

In various examples of this disclosure, “/” and “,” should be interpreted as indicating “and/or.” For example, “A/B” can mean “A and/or B.” Furthermore, “A, B” may mean “A and/or B.” Furthermore, “A/B/C” may mean “at least one of A, B and/or C.” Furthermore, “A, B, C” may mean “at least one of A, B and/or C.”

In various examples of this disclosure, “or” should be interpreted as indicating “and/or.” For example, “A or B” may include “only A,” “only B,” and/or “both A and B.” In other words, “or” should be interpreted as indicating “additionally or alternatively.”

Before explaining the present invention, 5G, a communication field to which the present invention can be applied, will be described.

Figure 1 illustrates a communication system applied to the present invention.

The three key requirements areas for 5G are (1) Enhanced Mobile Broadband (eMBB) area, (2) Massive Machine Type Communication (mMTC) area, and (3) Ultra-Reliable and Includes the area of ultra-reliable and low latency communications (URLLC).

Some use cases may require multiple areas for optimization, while others may focus on just one Key Performance Indicator (KPI). 5G supports these diverse use cases in a flexible and reliable way.

eMBB goes far beyond basic mobile Internet access and covers rich interactive tasks, media and entertainment applications in the cloud or augmented reality. Data is one of the key drivers of 5G, and we may not see dedicated voice services for the first time in the 5G era. In 5G, voice is expected to be processed simply as an application using the data connection provided by the communication system. The main reasons for the increased traffic volume are the increase in content size and the number of applications requiring high data rates. Streaming services (audio and video), interactive video and mobile Internet connections will become more prevalent as more devices are connected to the Internet. Many of these applications require always-on connectivity to push real-time information and notifications to users. Cloud storage and applications are rapidly increasing mobile communication platforms, and this can apply to both work and entertainment. And cloud storage is a particular use case driving growth in uplink data rates. 5G will also be used for remote work in the cloud and will require much lower end-to-end latency to maintain a good user experience when tactile interfaces are used. Entertainment, for example, cloud gaming and video streaming are other key factors driving increased demand for mobile broadband capabilities. Entertainment is essential on smartphones and tablets anywhere, including high mobility environments such as trains, cars and planes. Another use case is augmented reality for entertainment and information retrieval. Here, augmented reality requires very low latency and instantaneous amounts of data.

Additionally, one of the most anticipated 5G use cases concerns the ability to seamlessly connect embedded sensors in any field, or mMTC. By 2020, the number of potential IoT devices is expected to reach 20.4 billion. Industrial IoT is one area where 5G will play a key role in enabling smart cities, asset tracking, smart utilities, agriculture and security infrastructure.

URLLC includes new services that will transform industries through ultra-reliable/available low-latency links, such as remote control of critical infrastructure and self-driving vehicles. Levels of reliability and latency are essential for smart grid control, industrial automation, robotics, and drone control and coordination.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS) as a means of delivering streams rated at hundreds of megabits per second to gigabits per second. These high speeds are required to deliver TV at resolutions above 4K (6K, 8K and beyond) as well as virtual and augmented reality. Virtual Reality (VR) and Augmented Reality (AR) applications include nearly immersive sporting events. Certain applications may require special network settings. For example, for VR games, gaming companies may need to integrate core servers with a network operator's edge network servers to minimize latency.

Automotive is expected to be an important new driver for 5G, with many use cases for mobile communications for vehicles. For example, entertainment for passengers requires simultaneous, high capacity and high mobility mobile broadband. That's because future users will continue to expect high-quality connections regardless of their location and speed. Another use case in the automotive sector is augmented reality dashboards. It identifies objects in the dark and superimposes information telling the driver about the object's distance and movement on top of what the driver is seeing through the front window. In the future, wireless modules will enable communication between vehicles, information exchange between vehicles and supporting infrastructure, and information exchange between cars and other connected devices (eg, devices accompanied by pedestrians). Safety systems can reduce the risk of accidents by guiding drivers through alternative courses of action to help them drive safer. The next step will be remotely controlled or self-driven vehicles. This requires highly reliable and very fast communication between different self-driving vehicles and between cars and infrastructure. In the future, self-driving vehicles will perform all driving activities, leaving drivers to focus only on traffic abnormalities that the vehicles themselves cannot discern. The technical requirements of self-driving vehicles call for ultra-low latency and ultra-high reliability, increasing traffic safety to levels unachievable by humans.

Smart cities and smart homes, referred to as smart societies, will be embedded with high-density wireless sensor networks. A distributed network of intelligent sensors will identify conditions for cost-effective and energy-efficient maintenance of a city or home. A similar setup can be done for each household. Temperature sensors, window and heating controllers, burglar alarms and home appliances are all connected wirelessly. Many of these sensors are typically low data rate, low power, and low cost. However, real-time HD video may be required in certain types of devices for surveillance, for example.

Consumption and distribution of energy, including heat or gas, is highly decentralized, requiring automated control of distributed sensor networks. A smart grid interconnects these sensors using digital information and communications technologies to collect and act on information. This information can include the behavior of suppliers and consumers, allowing smart grids to improve the efficiency, reliability, economics, sustainability of production and distribution of fuels such as electricity in an automated manner. Smart grid can also be viewed as another low-latency sensor network.

Mission critical applications (e.g., e-health) are one of the 5G usage scenarios. The health sector has many applications that can benefit from mobile communications. Communications systems can support telemedicine, providing clinical care in remote locations. This can help reduce the barrier of distance and improve access to health services that are consistently unavailable in remote rural areas. It is also used to save lives in critical care and emergency situations. Mobile communications-based wireless sensor networks can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly important in industrial applications. Wiring is expensive to install and maintain. Therefore, the possibility of replacing cables with reconfigurable wireless links is an attractive opportunity for many industries. However, achieving this requires that wireless connections operate with similar latency, reliability and capacity as cables, and that their management be simplified. Low latency and very low error probability are new requirements needed for 5G connectivity.

Logistics and freight tracking are important examples of mobile communications that enable inventory and tracking of packages anywhere using location-based information systems. Use cases in logistics and cargo tracking typically require low data rates but require wide range and reliable location information.

Referring to Figure 1, a communication system includes a wireless device, a base station (BS), and a network. Although Figure 1 shows a 5G network as an example of a network of a communication system, implementations of this specification are not limited to the 5G system and can be applied to next-generation communication systems beyond the 5G system.

The BS and network may be implemented as wireless devices, and a specific wireless device 200 may operate as a BS/network node for other wireless devices.

A wireless device refers to a device that performs communication using radio access technology (RAT) (e.g., 5G NR (new RAT), LTE), and may be referred to as a communication/wireless/5G device. Although not limited thereto, wireless devices include robots 100a, vehicles 100b-1, 100b-2, extended reality (XR) devices 100c, hand-held devices 100d, It may include home appliances (100e), Internet of things (IoT) devices (100f), and artificial intelligence (AI) devices/servers (400). For example, vehicles may include vehicles equipped with wireless communication capabilities, autonomous vehicles, and vehicles capable of performing vehicle-to-vehicle communication. Here, the vehicle may include an unmanned aerial vehicle (UAV) (eg, drone).

XR devices may include augmented reality (AR)/virtual reality (VR)/mixed reality (MR) devices, head-mounted displays (HMDs), and devices mounted on vehicles. It can be implemented in the form of a head-up display (HUD), television, smartphone, computer, wearable device, home appliance, digital signage, vehicle, robot, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smartglasses), and computers (e.g., laptops). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

In this specification, wireless devices 100a to 100f may be referred to as UE. UEs include, for example, mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation, slate PCs, Tablet PCs, ultrabooks, vehicles, vehicles equipped with autonomous driving functions, connected cars, UAVs, AI modules, robots, AR devices, VR devices, MR devices, hologram devices, public safety devices, MTC devices, IoT devices, medical It may include devices, fintech devices (or financial devices), security devices, climate/environment devices, devices related to 5G services, or devices related to the 4th Industrial Revolution field.

For example, a UAV may be an aircraft that flies by radio control signals without a person on board. VR devices may include, for example, devices that implement objects or backgrounds of a virtual world. For example, an AR device may include a device implemented by connecting an object or background in a virtual world to an object or background in the real world. MR devices may include, for example, devices implemented by fusing objects or backgrounds in the virtual world with objects or backgrounds in the real world. For example, a holographic device may include a device that records and reproduces three-dimensional information to create a 360-degree stereoscopic image by utilizing the light interference phenomenon that occurs when two laser lights meet, called holography. Public safety devices may include, for example, video relay devices or video devices that can be worn on the user's body. MTC devices and IoT devices, for example, may be devices that do not require direct human intervention or manipulation. For example, MTC devices and IoT devices may include smart meters, bending machines, thermometers, smart light bulbs, door locks, or various sensors.

A medical device may be, for example, a device used for the purpose of diagnosing, treating, mitigating, treating, or preventing a disease. For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, or correcting an injury or disability. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying structure or function. For example, a medical device may be a device used for the purpose of controlling pregnancy. For example, medical devices may include medical devices, surgical devices, (in vitro) diagnostic devices, hearing aids, or surgical devices. For example, a security device may be a device installed to prevent risks that may occur and maintain safety. For example, a security device may be a camera, CCTV, recorder, or black box. A fintech device may be, for example, a device that can provide financial services such as mobile payments. For example, fintech devices may include payment devices or point of sales (POS). Climate/environment devices may include, for example, devices that monitor or predict climate/environment.

Wireless devices 100a to 100f may be connected to the network 300 through the BS 200. AI technology may be applied to wireless devices (100a to 100f), and the wireless devices (100a to 100f) may be connected to the AI server 400 through the network 300. The network 300 may be configured using a 3G network, 4G (eg, LTE) network, 5G (eg, NR) network, and beyond 5G network. Wireless devices 100a to 100f may communicate with each other through the BS 200/network 300, but may also communicate directly (e.g. sidelink communication) without going through the BS/network. For example, vehicles 100b-1 and 100b-2 may perform direct communication (e.g. vehicle-to-vehicle (V2V)/vehicle-to-everything (V2X) communication). Additionally, an IoT device (eg, sensor) may communicate directly with another IoT device (eg, sensor) or another wireless device (100a to 100f).

Wireless communication/connection (150a, 150b) may be performed between wireless devices (100a to 100f)/BS (200) and BS (200). Here, wireless communication/connection may be achieved through various RATs (e.g., 5G NR) such as uplink/downlink communication (150a) and sidelink communication (150b) (or D2D communication). Through wireless communication/connection (150a, 150b), the wireless device and the BS/wireless device can transmit/receive wireless signals to each other. For example, wireless communication/connection 150a and 150b may transmit/receive signals through various physical channels. To this end, based on the various proposals of this specification, various configuration information configuration processes for transmitting/receiving wireless signals, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping) and at least part of the resource allocation process may be performed.

2 is a block diagram illustrating examples of communication devices capable of performing methods according to the present disclosure.

Referring to FIG. 2, the first wireless device 100 and the second wireless device 200 can transmit/receive wireless signals to/from external devices through various RATs (eg, LTE, NR). {The first wireless device 100 and the second wireless device 200} are {wireless devices 100a to 100f and BS 200} and/or {wireless devices 100a to 100f and wireless devices ( 100a~100f)}.

The first wireless device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and/or one or more antennas 108. Processor(s) 102 controls memory(s) 104 and/or transceiver(s) 106 and may be configured to implement the functions, procedures and/or methods described herein. For example, processor(s) 102 processes information in memory(s) 104 to generate first information/signals and then includes the first information/signals through transceiver(s) 106. can transmit wireless signals. In addition, the processor(s) 102 receives wireless signals including the second information/signals through the transceiver 106, and then stores the information obtained by processing the second information/signals in the memory(s) 104. You can save it. Memory(s) 104 may be connected to the processor(s) 102 and may store various information related to the operation of the processor(s) 102. For example, memory(s) 104 may perform some or all of the processes controlled by processor(s) 102 or may include instructions for performing the procedures and/or methods described herein. Software code can be stored. Here, the processor(s) 102 and memory(s) 104 may be part of a communication modem/circuit/chip designed to implement RAT (eg, LTE, NR). Transceiver(s) 106 may be coupled to processor(s) 102 and may transmit and/or receive wireless signals via one or more antennas 108. Each of the transceiver(s) 106 may include a transmitter and/or receiver. Transceiver(s) 106 may be used interchangeably with radio frequency (RF) unit(s). In the present invention, a wireless device may mean a communication modem/circuit/chip.

The second wireless device 200 includes one or more processors 202, one or more memories 204, and may further include one or more transceivers 206 and/or one or more antennas 208. Processor(s) 202 may control memory(s) 204 and/or transceiver(s) 206 and may be configured to implement the functions, procedures and/or methods described herein. there is. For example, processor(s) 202 processes information in memory(s) 204 to generate third information/signals and then includes the third information/signals through transceiver(s) 206. can transmit wireless signals. In addition, the processor(s) 202 receives wireless signals including the fourth information/signals through the transceiver(s) 206, and then stores the information obtained by processing the fourth information/signals in memory(s) ( 204). Memory(s) 204 may be connected to the processor(s) 202 and may store various information related to the operation of the processor(s) 202. For example, memory(s) 204 may perform some or all of the processes controlled by processor(s) 202 or may include instructions for performing the procedures and/or methods described herein. Software code can be stored. Here, the processor(s) 202 and memory(s) 204 may be part of a communication modem/circuit/chip designed to implement RAT (eg, LTE, NR). Transceiver(s) 206 may be coupled to processor(s) 202 and may transmit and/or receive wireless signals via one or more antennas 208. Each of the transceiver(s) 206 may include a transmitter and/or receiver. Transceiver(s) 206 may be used interchangeably with the RF unit. In the present invention, a wireless device may mean a communication modem/circuit/chip.

Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may operate on one or more layers (e.g., a physical (PHY) layer, a medium access control (MAC) layer, and a radio link control (RLC) layer. , functional layers such as packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP)) can be implemented. One or more processors 102, 202 may process one or more protocol data units (PDUs) and/or one or more service data units (PDUs) in accordance with the functions, procedures, proposals and/or methods disclosed herein. data unit (SDU) can be created. One or more processors 102, 202 may generate messages, control information, data or information in accordance with the functions, procedures, suggestions and/or methods disclosed herein. One or more processors 102, 202 may process signals (e.g., baseband signals) containing PDUs, SDUs, messages, control information, data or information in accordance with the functions, procedures, suggestions and/or methods disclosed herein. (baseband) signals) can be generated and provided to one or more transceivers (106, 206). One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206 and may utilize the functions, procedures, proposals, and/or methods disclosed herein. Depending on the device, PDU, SDU, message, control information, data or information can be obtained.

One or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) May be included in one or more processors 102 and 202. The functions, procedures, suggestions and/or methods disclosed in this specification may be implemented using firmware or software, and firmware or software may be implemented to include modules, procedures or functions. Firmware or software configured to perform the functions, procedures, suggestions and/or methods disclosed herein may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) to be used by one or more processors (102, 202). It can be driven by (102, 202). The functions, procedures, suggestions and/or methods disclosed in this specification may be implemented using firmware or software in the form of code, instructions and/or sets of instructions.

One or more memories 104, 204 may be coupled with one or more processors 102, 202 and may store various types of data, signals, messages, information, programs, code, instructions, and/or commands. . One or more memories 104 and 204 may include read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drives, registers, cache memory, and computer-readable storage media. and/or a combination thereof. One or more memories 104, 204 may be located internal to and/or external to one or more processors 102, 202. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various technologies, such as wired or wireless connections.

One or more transceivers 106, 206 may transmit user data, control information, and/or wireless signals/channels mentioned in the methods and/or operational flowcharts of this specification to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, and/or wireless signals referenced in the functions, procedures, proposals, methods and/or operational flowcharts disclosed in this specification from one or more other devices. Channels can be received. For example, one or more transceivers 106, 206 may be coupled with one or more processors 102, 202 and may transmit and/or receive wireless signals. For example, one or more processors 102 and 202 may control one or more transceivers 106 and 206 to transmit user data, control information or wireless signals to one or more other devices. Additionally, one or more processors 102 and 202 may control one or more transceivers 106 and 206 to receive user data, control information or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may perform the functions disclosed in this specification via one or more antennas (108, 208), It may be configured to transmit and/or receive user data, control information, and/or wireless signals/channels referenced in the procedures, suggestions, methods and/or operational flowcharts. In this specification, one or more antennas may be multiple physical antennas or multiple logical antennas (eg, antenna ports). One or more transceivers (106, 206) process received user data, control information, wireless signals/channels, etc. using one or more processors (102, 202). It can convert RF band signals to baseband signals. One or more transceivers 106, 206 may convert processed user data, control information, wireless signals/channels, etc. from baseband signals to RF band signals using one or more processors 102, 202. . For this purpose, one or more transceivers 106, 206 may comprise (analog) oscillators and/or filters. For example, the transceiver 106, 206 upconverts OFDM baseband signals to a carrier frequency by (analog) oscillators and/or filters of the transceiver under the control of the processor 102, 202, and converts the OFDM baseband signals up from the carrier frequency. Converted OFDM signals can be transmitted. The transceiver (106, 206) receives OFDM signals at a carrier frequency and down-converts the OFDM signals to OFDM baseband signals by the (analog) oscillators and/or filters of the transceiver (102, 202) under the control of the transceiver (102, 202). You can.

In implementations of this specification, the UE may operate as a transmitting device in the uplink and as a receiving device in the downlink. In implementations of this specification, the BS may operate as a receiving device in the uplink and as a transmitting device in the downlink. Hereinafter, for convenience of explanation, unless otherwise stated or explained, it is mainly assumed that the first wireless device 100 operates as a UE and the second wireless device 200 operates as a BS. For example, the processor(s) 102 connected to, mounted on, or launched into the first wireless device 100 are configured to perform UE operations according to an implementation of the present specification or are configured to perform UE operations according to an implementation of the present specification. It may be configured to control the transceiver 106. Processor(s) 202 connected to, mounted on, or launched into the second wireless device 200 are configured to perform BS operations according to an implementation of the present specification or transmitter/receiver(s) to perform BS operations according to an implementation of the present specification. It may be configured to control (206).

In the present specification, at least one memory (e.g., 104 or 204) contains instructions or programs that, when executed, cause at least one processor operably connected thereto to perform operations according to some embodiments or implementations of the present specification. You can save it.

In the present specification, a computer-readable storage medium stores at least one instruction or computer program that, when executed by at least one processor, causes the at least one processor to perform operations according to some embodiments or implementations of the present specification. .

In the present specification, a processing device or device includes at least one processor, and connectable to the at least one processor, and, when executed, causes the at least one processor to perform operations according to some embodiments or implementations of the present specification. It may include at least one computer memory storing instructions.

3 illustrates operations of wireless devices based on implementations of the present specification.

The first wireless device 100 generates first information/signals according to the functions, procedures and/or methods described in this specification, and then transmits wireless signals containing the first information/signals to the second wireless device. It can be transmitted wirelessly at (200) (S10). The first information/signals may include data unit(s) of the present specification (eg, PDU, SDU, RRC message). The first wireless device 100 may receive wireless signals including second information/signals from the second wireless device 200 (S30) and then perform operations based on or according to the second information/signals. There is (S50). Second information/signals may be transmitted by the second wireless device 200 to the first wireless device 100 in response to the first information/signals. The second information/signals may include data unit(s) of the present specification (eg, PDU, SDU, RRC message). The first information/signals may include content request information, and the second information/signals may include content specific to the intended use of the first wireless device 100. Some examples of operations specific to the use of wireless devices 100, 200 will be described below.

In some scenarios, first wireless device 100 may be portable device 100d of FIG. 1 that performs the functions, procedures, and/or methods described herein. The mobile device 100d may acquire information/signals (e.g., touch, text, voice, image, or video) input by the user and convert the obtained information/signals into first information/signals. . The mobile device 100d may transmit first information/signals to the second wireless device 200 (S10). The second wireless device 200 may be one of the wireless devices 100a to 100f of FIG. 1 or a BS. The mobile device 100d may receive second information/signals from the second wireless device 200 (S30) and perform an operation based on the second information/signals (S50). For example, the mobile device 100d outputs the contents of the second information/signals to the user (e.g., in the form of text, voice, image, video, or haptics) through the I/O unit of the mobile device 100d. You can.

In some scenarios, first wireless device 100 may be a vehicle or autonomous vehicle 100b that performs the functions, procedures and/or methods described herein. The vehicle 100b transmits signals (e.g., data and control signals) to external devices such as other vehicles, BS (e.g., gNB and roadside devices), and servers through a communication unit (e.g., communication unit 110 in FIG. 1C). and can transmit (S10) and receive (S30) from an external device. The vehicle 100b may include a driving unit, and the driving unit may allow the vehicle 100b to travel on the road. The driving unit of the vehicle 100b may include an engine, motor, powertrain, wheels, brakes, steering equipment, etc. The vehicle 100b may include a sensor unit for acquiring vehicle status, surrounding environment information, user information, etc. The vehicle 100b may generate first information/signals and transmit them to the second wireless device 200 (S10). The first information/signals may include vehicle status information, surrounding environment information, user information, etc. The vehicle 100b may receive second information/signals from the second wireless device 200 (S30). The second information/signals may include vehicle status information, surrounding environment information, user information, etc. The vehicle 100b can drive on the road, stop, or adjust its speed based on the second information/signals (S50). For example, the vehicle 100b may receive second information/signals including map data and traffic information data from an external server (S30). The vehicle 100b may generate an autonomous driving path and a driving plan based on the second information/signals and move along the autonomous driving path (eg, speed/direction control) according to the driving plan (S50). As another example, the control unit or processor(s) of the vehicle 100b may generate a virtual object based on map information, traffic information, and vehicle location information acquired through the GPS sensor of the vehicle 100b, and The I/O unit 140 may display the created virtual object on the window of the vehicle 100b (S50).

In some scenarios, first wireless device 100 may be XR device 100c of FIG. 1 that performs the functions, procedures and/or methods described herein. The XR device 100c transmits signals (e.g., media data and control signals) to and from external devices such as other wireless devices, mobile devices, or media servers through a communication unit (e.g., communication unit 110 in Figure 1C). Can transmit (S10) and receive (S30). For example, the XR device 100c transmits content request information to another device or media server (S10), downloads/streams content such as movies or news from another device or media server (S30), and wirelessly receives Based on the second information/signals, an XR object (e.g., AR/VR/MR object) is generated, output, or displayed through the I/O unit of the XR device (S50).

In some scenarios, first wireless device 100 may be robot 100a of FIG. 1 that performs the functions, procedures and/or methods described herein. The robot 100a may be classified into industrial robots, medical robots, household robots, military robots, etc. depending on the purpose or field of use. The robot 100a transmits signals (e.g., driving information and control signals) to and from external devices such as other wireless devices, other robots, or control servers through a communication unit (e.g., communication unit 110 in FIG. 1C). Can transmit (S10) and receive (S30). The second information/signals may include driving information and control signals for the robot 100a. The controller or processor(s) of the robot 100a may control the movement of the robot 100a based on the second information/signals.

In some scenarios, the first wireless device 100 may be the AI device 400 of FIG. 1 . AI devices include TVs, projectors, smartphones, PCs, laptops, digital broadcasting terminals, tablet PCs, wearable devices, set-top boxes (STBs), radios, washing machines, refrigerators, digital signage, robots, vehicles, etc. It can be implemented by a fixed device or a mobile device. The AI device 400 uses wired and wireless communication technology to connect to and from external devices such as other AI devices (e.g., 100a,..., 100f, 200 or 400 in FIG. 1) or AI servers (e.g., 400 in FIG. 1). from. Wired and wireless signals (e.g., sensor information, user input, learning model, or control signal) may be transmitted (S10) and received (S30). The control unit or processor(s) of the AI device 400 may determine at least one executable operation of the AI device 400 based on information determined or generated using a data analysis algorithm or a machine learning algorithm. The AI device 400 may request that an external device, such as another AI device or an AI server, provide sensor information, user input, learning model, control signals, etc. to the AI device 400 (S10). The AI device 400 may receive second information/signals (e.g., sensor information, user input, learning model, or control signal) (S30), and the AI device 400 may receive the second information/signals based on the second information/signals. Thus, the operation determined to be preferred among the predicted operation or at least one executable operation can be performed (S50).

Below, before explaining the present invention, the protocol stack in a 3GPP-based wireless communication system will be described.

First, in a 3GPP-based wireless communication system, the protocol stack can be divided into a radio interface user plane protocol stack between a terminal (UE) and a base station (BS) and a radio interface control plane protocol stack between the UE and the BS. The control plane refers to the path through which control messages used by the UE and the network to manage calls are transmitted. The user plane refers to the path through which data generated in the application layer, for example, voice data or Internet packet data, is transmitted.

The user plane protocol stack can be divided into a first layer (layer 1) (i.e., physical (PHY) layer) and a second layer (layer 2).

The control plane protocol stack consists of Layer 1 (i.e., PHY layer), Layer 2, and Layer 3 (e.g., radio resource control (RRC) layer and non-access stratum (NAS) layer). Layer 1, Layer 2, and Layer 3 are referred to as access stratum (AS).

The NAS control protocol terminates in an access management function (AMF) on the network side and performs authentication, mobility management, security control, etc.

In the 3GPP LTE system, layer 2 is divided into the following sublayers: medium access control (MAC), radio link control (RLC), and packet data convergence protocol. PDCP). In the 3GPP NR (New Radio) system, layer 2 is divided into the following sublayers: MAC, RLC, PDCP, and service data adaptation protocol (SDAP). The PHY layer provides a transmission channel to the MAC sublayer, the MAC sublayer provides a logical channel to the RLC sublayer, the RLC sublayer provides an RLC channel to the PDCP sublayer, and the PDCP sublayer provides a wireless channel to the SDAP sublayer. Provides a bearer. The SDAP sublayer provides QoS flows to the 5G core network.

In 3GPP NR systems, the main services and functions of SDAP may include mapping between QoS flows and data radio bearers and marking of QoS flow ID (QFI) in both DL and UL packets, which is a single protocol entity of SDAP. is set for each individual PDU session.

In the 3GPP NR system, the main services and functions of the RRC sublayer include broadcasting of system information related to AS and NAS; Paging initiated by 5GC or NG-RAN; Establishment, maintenance and release of RRC connection between UE and NG-RAN; Security features including key management; Establishment, establishment, maintenance and release of signaling radio bearer (SRB) and data radio bearer (DRB); Mobility functions (including handover and context transfer; UE cell selection and reselection and control of cell selection and reselection; inter-RAT mobility); Control of QoS management functions, UE measurement reporting and reporting; Detection of wireless link failure and recovery from wireless link failure; It may include delivering NAS messages from the UE to the NAS and from the NAS to the UE.

In 3GPP NR systems, the main services and functions of the PDCP sublayer for the user plane are header compression and decompression (robust header compression (ROHC) only); Passing user data; reordering and duplicate detection; sequential transmission; PDCP PDU routing (for split bearer); retransmission of PDCP SDU; ciphering, deciphering and integrity protection; PDCP SDU disposal; PDCP re-establishment and data recovery for RLC AM; PDCH status report for RLC AM; PDCP may include instructions for duplicating PDUs and discarding duplication to lower layers.

Additionally, the main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; control plane data passing; rearrangement and duplication detection; sequential transmission; It may contain instructions for duplication of PDCP PDUs and discarding of duplication to lower layers.

In the 3GPP NR system, the RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). RLC settings can be applied for each logical channel without being dependent on numerology and/or transmission section. In the 3GPP NR system, the main services and functions of the RLC sublayer depend on the transmission mode, including delivery of upper layer PDUs; Sequence numbering (for UM and AM) independent of numbering in PDCP; Error correction via ARQ (automatic repeat request) (AM only); Segmentation (for UM and AM) and re-segmentation (for AM only) of RLC SDUs; reassembly of SDU (for UM and AM); RLC SDU discard (for UM and AM); RLC re-establishment; Includes protocol error detection (AM only).

In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; Multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels to/from a transport block (TB) passed to/from the PHY layer via the transport channel; reporting scheduling information; Error correction via HARQ (hybrid automatic repeat request) (one HARQ entity per cell for CA); Priority handling between UEs using dynamic scheduling; Priority handling between logical channels of one UE using logical channel priorities; Padding. A single MAC entity can support multiple numerology, transmission timing, and cells. Mapping constraints in logical channel priority control which numerology(s), cell(s) and transmission timing(s) a logical channel can use.

Additionally, different types of data transmission services are provided by MAC. In order to accommodate different types of data transmission services, multiple logical channel types are defined, that is, each logical channel type supports transmission of a specific type of information. Each logical channel type is defined by what type of information is transmitted. Logical channels are classified into two groups: control channels and traffic channels. The control channel is used to transmit only control plane information, and the traffic control channel is used to transmit only user plane information.

The broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, and the paging control channel (PCCH) is a downlink logical channel for delivering paging information and system information change notification. channel, and the common control channel (CCCH) is a logical channel for transmitting control information between the UE and the network. It is a channel used for UEs that do not have an RRC connection to the network, and the dedicated control channel (DCCH) is a point-to-point bidirectional logic that transmits dedicated control information between the UE and the network. As a channel, it is a channel used by a UE with an RRC connection.

A dedicated traffic channel (DTCH) is a point-to-point logical channel dedicated to a single UE for conveying user information. DTCH can exist in both uplink and downlink.

In the downlink, the connections between logical channels and transport channels are as follows: BCCH can be mapped to BCH; BCCH may be mapped to a downlink shared channel (DL-SCH); PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; DTCH can be mapped to DL-SCH.

In the uplink, the connections between logical channels and transport channels are as follows: CCCH can be mapped to an uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; DTCH can be mapped to UL-SCH.

Meanwhile, in recent 5G systems, there is a consensus that when MBMS (Multicast & Broadcast Multimedia System) is in operation, it is possible to decide whether to transmit in the multicast or unicast method depending on the wireless quality. It has been achieved, but the detailed operation is under discussion.

In particular, a recently discussed technology considers switching between multicast and unicast transmission methods depending on wireless quality. However, even if this method is followed, there is a problem that it is difficult for the network operator to recognize when/in which area/whether the transmission method has changed due to a decrease in wireless quality.

Accordingly, in the present invention, when a 5G base station provides MBMS service to a terminal and changes the transmission method between multicast and unicast, the terminal reports information on the location and change time of the transmission method, and additionally provides a predetermined message when changing the transmission method. We propose a method of reporting wireless quality indicators to the base station.

Additionally, based on this reported information, the network proposes ways to improve the quality of broadcasting services through machine learning or automatic changes in parameters related to service provision to terminals.

Figure 4 illustrates a structural diagram of MAC channel mapping and physical channel mapping when transmitting MBS data in a 5G system to which the present invention can be applied.

Referring to FIG. 4, when MBS data is transmitted, it is divided into PTM transmission, which is a multicast transmission, and PTP transmission, which is a unicast transmission, and is transmitted to the terminal.

Multicast transmission is divided into groups (Group RNTI; G-RNTI), and unicast is transmitted to the terminal by C-RNTI. Data is generally transmitted in a multicast manner, but in case of poor wireless environment, it is transmitted to the terminal at the discretion of the base station. By changing to unicast method, stable broadcasting service will be provided.

In the present invention, when changing from PTM transmission to PTP transmission, a procedure is added to report the terminal's location, time, and radio quality information to the base station, so that the base station and the server connected to the base station use the information to analyze and optimize broadcast quality.

In particular, the quality information consists of the terminal's RSRP (Reference Signal Received Power)/SNR (signal-to-noise ratio)/RSSI (Received Signal Strength Indicator), and when the terminal changes from PTM transmission to PTP transmission, the corresponding information is sent. Report to base station. Here, RSRP is the average value of the strength of the reference signal belonging to a specific cell in the frequency band. In addition, RSSI refers to the received signal strength index, and generally transmits a strength ranging from 99 dBm to 35 dBm, and the higher the number, the stronger the signal strength. Lastly, SNR is the signal-to-noise ratio, which is a quality indicator that measures the relative size of signal to noise.

Preferably, MCS (Modulation and Coding Scheme) information is also included in the quality information, and the MCS information for PTM transmission and the MCS information for PTP transmission are averaged over a certain period of time and transmitted to the base station. Of course, the MCS information is not something that the terminal reports to the base station, but the base station can calculate it itself through multicast transmission information and unicast transmission information, and store it together with the report information received from the terminal.

It will be described in more detail with reference to the drawings.

Figure 5 shows an example of reporting a multicast transmission failure according to an embodiment of the present invention.

Referring to FIG. 5, when the terminal moves to a place with poor wireless quality and leaves the multicast available area, it is desirable for the terminal to inform the base station of the corresponding information through a multicast transmission failure report.

In this case, according to Figure 5, when reporting a multicast transmission failure, the terminal's location information, time, and radio quality information (RSRP, SNR, RSSI) can be transmitted.

Figure 6 shows an example of performing unicast transmission according to an embodiment of the present invention.

Referring to FIG. 6, the base station changes MBS data from multicast transmission to unicast transmission, and at this time, information about the change is transmitted to the terminal through an RRC message or a physical layer signal masked with C-RNTI.

At this time, the base station can average and store the MCS levels assigned to the terminal over a predetermined period of time, and store it after mapping it together with information received from the terminal when reporting an existing multicast failure. In particular, based on the multicast transmission failure report, the MCS level allocated to the terminal in the multicast method during the first time unit is stored, and additionally, the MCS allocated to the terminal in the unicast method for the second time unit after changing to the unicast method You can save the level.

Figure 7 illustrates a multicast transmission failure report stored in a base station according to an embodiment of the present invention.

In particular, in Figure 7, it can be seen that information related to the failure report time, location, and wireless quality is stored based on the terminal (UE) that performed the multicast transmission failure report.

Additionally, based on the terminal (UE) that performed the multicast transmission failure report, the MCS level assigned to the UE in the multicast method for the first time unit and the unicast method to the UE for the second time unit after changing to the unicast method You can see that the MCS level assigned is saved together.

The base station may transmit the table of FIG. 7 to the upper server or OAM (Operation Administration & Monitor) server. The network operator can reflect the information on the map to configure MBS coverage or change parameters for providing multicast services.

The embodiments described above combine the components and features of the present invention in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features. Additionally, it is also possible to configure an embodiment of the present invention by combining some components and/or features. The order of operations described in embodiments of the present invention may be changed. Some features or features of one embodiment may be included in other embodiments or may be replaced with corresponding features or features of other embodiments. It is obvious that claims that do not have an explicit reference relationship in the patent claims can be combined to form an embodiment or included as a new claim through amendment after filing.

The steps of the method or algorithm described in connection with the embodiments disclosed herein may be implemented directly as hardware, software modules, or a combination of the two executed by a processor. Software modules may reside in a storage medium (i.e., memory and/or storage) such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM.

An exemplary storage medium is coupled to a processor, the processor capable of reading information from and writing information to the storage medium. Alternatively, the storage medium may be integral with the processor. The processor and storage medium may reside within an application specific integrated circuit (ASIC). The ASIC may reside within the user terminal. Alternatively, the processor and storage medium may reside as separate components within the user terminal.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present invention.

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but rather to explain it, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

Claims (18)

As a method for a base station to transmit data to a terminal,
transmitting the data to the terminal in a multicast manner;
Receiving a multicast transmission failure report from the terminal;
calculating an average MCS level provided to the terminal through the multicast method for a specific time;
transmitting the data to the terminal in a unicast manner; and
Transmitting the average MCS level and the information included in the failure report to an Operation Administration & Monitor (OAM) server,
The above failure report is:
Characterized in that it includes at least one of the terminal's failure report transmission point, the terminal's failure report transmission location, and wireless quality information at the time of the terminal's failure report.
Data transmission method. delete delete According to paragraph 1,
The step of transmitting the data in the unicast method includes:
Characterized in that it includes the step of transmitting an indicator indicating a change from the multicast method to the unicast method.
Data transmission method. According to paragraph 1,
When reporting a failure of the terminal, the wireless quality information is,
Characterized by including at least one of Reference Signal Received Power (RSRP), signal-to-noise ratio (SNR), and Received Signal Strength Indicator (RSSI),
Data transmission method. According to paragraph 1,
The above failure report is:
Characterized in that it is received from the terminal when the terminal moves outside the coverage of the multicast method,
Data transmission method. As a base station device,
wireless communication module;
Memory; and
Includes a processor,
The processor,
Send data to the terminal in a multicast manner,
Receiving a report of failure of multicast transmission from the terminal,
Calculate the average MCS level provided through the multicast method for a specific time to the terminal,
Transmitting the data to the terminal in a unicast manner,
Controlling the base station device to transmit the average MCS level and the information included in the failure report to an Operation Administration & Monitor (OAM) server,
The above failure report is:
Characterized in that it includes at least one of the terminal's failure report transmission point, the terminal's failure report transmission location, and wireless quality information at the time of the terminal's failure report.
Base station device. delete delete In clause 7,
The processor,
When transmitting the data in the unicast method, an indicator indicating a change from the multicast method to the unicast method is transmitted,
Base station device. In clause 7,
When reporting a failure of the terminal, the wireless quality information is,
Characterized by including at least one of Reference Signal Received Power (RSRP), signal-to-noise ratio (SNR), and Received Signal Strength Indicator (RSSI),
Base station device. In clause 7,
The above failure report is:
Characterized in that it is received from the terminal when the terminal moves outside the coverage of the multicast method,
Base station device. A non-volatile computer-readable storage medium storing at least one computer program that, when executed by at least one processor, includes instructions that cause the at least one processor to perform operations that cause a base station to transmit data to a terminal. ,
The above operations are:
transmitting the data to the terminal in a multicast manner;
Receiving a multicast transmission failure report from the terminal;
calculating an average MCS level provided to the terminal through the multicast method for a specific time;
transmitting the data to the terminal in a unicast manner; and
Transmitting the average MCS level and the information included in the failure report to an Operation Administration & Monitor (OAM) server,
The above failure report is:
Characterized in that it includes at least one of the terminal's failure report transmission point, the terminal's failure report transmission location, and wireless quality information at the time of the terminal's failure report.
A non-volatile computer-readable storage medium. delete delete According to clause 13,
The step of transmitting the data in the unicast method includes:
Characterized in that it includes the step of transmitting an indicator indicating a change from the multicast method to the unicast method.
A non-volatile computer-readable storage medium. According to clause 13,
When reporting a failure of the terminal, the wireless quality information is,
Characterized by including at least one of Reference Signal Received Power (RSRP), signal-to-noise ratio (SNR), and Received Signal Strength Indicator (RSSI),
A non-volatile computer-readable storage medium. According to clause 13,
The above failure report is:
Characterized in that it is received from the terminal when the terminal moves outside the coverage of the multicast method,
A non-volatile computer-readable storage medium.