Patent Application
20240381471
The present disclosure relates to failure detection and notification in wireless communications.
3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
Work has started in international telecommunication union (ITU) and 3GPP to develop requirements and specifications for new radio (NR) systems. 3GPP has to identify and develop the technology components needed for successfully standardizing the new RAT timely satisfying both the urgent market needs, and the more long-term requirements set forth by the ITU radio communication sector (ITU-R) international mobile telecommunications (IMT)-2020 process. Further, the NR should be able to use any spectrum band ranging at least up to 100 GHz that may be made available for wireless communications even in a more distant future.
The NR targets a single technical framework addressing all usage scenarios, requirements and deployment scenarios including enhanced mobile broadband (eMBB), massive machine-type-communications (mMTC), ultra-reliable and low latency communications (URLLC), etc. The NR shall be inherently forward compatible.
In wireless communications, various types of failures can be defined such as radio link failure (RLF), beam failure and/or handover failure (HOF). For example, in an integrated access and backhaul (IAB) network, an IAB node may detect an RLF on a backhaul (BH) link between the IAB node and its parent node. Such RLF on BH may be referred to as BH RLF. After detecting the BH RLF, the IAB node may transmit a notification of the BH RLF (e.g., BH RLF indication) to its child node.
An aspect of the present disclosure is to provide method and apparatus for failure detection and notification in a wireless communication system.
According to an embodiment of the present disclosure, a method performed by a first wireless device in a wireless communication system comprises: establishing a respective backhaul connection with a second wireless device and a third wireless device: performing a transmission via a routing path to the second wireless device; detecting a problem of a backhaul connection between the first wireless device and the second wireless device: determining whether the routing path can be switched from the second wireless device to the third wireless device based on detecting the problem; and based on a determination that the routing path cannot be switched, transmitting a notification of the problem to a fourth wireless device.
According to an embodiment of the present disclosure, a method performed by a fourth wireless device adapted to operate in a wireless communication system comprises: establishing a backhaul connection with a first wireless device having a respective backhaul connection with a second wireless device and a third wireless device: performing a transmission via a first routing path to the first wireless device, wherein the transmission is routed from the first wireless to the second wireless device over a second routing path: based on the second routing path being unable to be switched from the second wireless device to the third wireless device after a problem of a backhaul connection between the first wireless device and the second wireless device occurs, receiving a notification of the problem from the first wireless device; and switching the first routing path from the first wireless device to another wireless device based on receiving the notification of the problem.
According to an embodiment of the present disclosure, apparatuses implementing the above methods are provided.
The present disclosure can have various advantageous effects.
For example, a node capable of performing a local re-routing when BH RLF occurs does not transmit a BH RLF detection indication to its child node so that unnecessary local re-routing by the child node and unnecessary BH RLF signaling can be avoided.
Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and/or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.
The following techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of the multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, and a multicarrier frequency division multiple access (MC-FDMA) system. CDMA may be embodied through radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be embodied through radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA may be embodied through radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is a part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolved version of 3GPP LTE.
For convenience of description, implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.
For terms and technologies which are not specifically described among the terms of and technologies employed in the present disclosure, the wireless communication standard documents published before the present disclosure may be referenced.
In the present disclosure, “A or B” may mean “only A”, “only B”, or “both A and B”. In other words, “A or B” in the present disclosure may be interpreted as “A and/or B”. For example, “A, B or C” in the present disclosure may mean “only A”, “only B”, “only C”, or “any combination of A, B and C”.
In the present disclosure, slash (/) or comma (,) may mean “and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B or C”.
In the present disclosure, “at least one of A and B” may mean “only A”, “only B” or “both A and B”. In addition, the expression “at least one of A or B” or “at least one of A and/or B” in the present disclosure may be interpreted as same as “at least one of A and B”.
In addition, in the present disclosure, “at least one of A, B and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. In addition, “at least one of A, B or C” or “at least one of A, B and/or C” may mean “at least one of A, B and C”.
Also, parentheses used in the present disclosure may mean “for example”. In detail, when it is shown as “control information (PDCCH)”, “PDCCH” may be proposed as an example of “control information”. In other words, “control information” in the present disclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as an example of “control information”. In addition, even when shown as “control information (i.e., PDCCH)”, “PDCCH” may be proposed as an example of “control information”.
Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.
Throughout the disclosure, the terms ‘radio access network (RAN) node’, ‘base station’, ‘eNB’, ‘gNB’ and ‘cell’ may be used interchangeably. Further, a UE may be a kind of a wireless device, and throughout the disclosure, the terms ‘UE’ and ‘wireless device’ may be used interchangeably.
Throughout the disclosure, the terms ‘cell quality’, ‘signal strength’, ‘signal quality’, ‘channel state’, ‘channel quality’, ‘channel state/reference signal received power (RSRP)’ and ‘reference signal received quality (RSRQ)’ may be used interchangeably.
Although not limited thereto, various descriptions, functions, procedures, suggestions, methods and/or operational flowcharts of the present disclosure disclosed herein can be applied to various fields requiring wireless communication and/or connection (e.g., 5G) between devices.
Hereinafter, the present disclosure will be described in more detail with reference to drawings. The same reference numerals in the following drawings and/or descriptions may refer to the same and/or corresponding hardware blocks, software blocks, and/or functional blocks unless otherwise indicated.
The 5G usage scenarios shown in
Three main requirement categories for 5G include (1) a category of enhanced mobile broadband (eMBB), (2) a category of massive machine type communication (mMTC), and (3) a category of ultra-reliable and low latency communications (URLLC).
Partial use cases may require a plurality of categories for optimization and other use cases may focus only upon one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable method.
eMBB far surpasses basic mobile Internet access and covers abundant bidirectional work and media and entertainment applications in cloud and augmented reality. Data is one of 5G core motive forces and, in a 5G era, a dedicated voice service may not be provided for the first time. In 5G, it is expected that voice will be simply processed as an application program using data connection provided by a communication system. Main causes for increased traffic volume are due to an increase in the size of content and an increase in the number of applications requiring high data transmission rate. A streaming service (of audio and video), conversational video, and mobile Internet access will be more widely used as more devices are connected to the Internet. These many application programs require connectivity of an always turned-on state in order to push real-time information and alarm for users. Cloud storage and applications are rapidly increasing in a mobile communication platform and may be applied to both work and entertainment. The cloud storage is a special use case which accelerates growth of uplink data transmission rate. 5G is also used for remote work of cloud. When a tactile interface is used, 5G demands much lower end-to-end latency to maintain user good experience. Entertainment, for example, cloud gaming and video streaming, is another core element which increases demand for mobile broadband capability. Entertainment is essential for a smartphone and a tablet in any place including high mobility environments such as a train, a vehicle, and an airplane. Other use cases are augmented reality for entertainment and information search. In this case, the augmented reality requires very low latency and instantaneous data volume.
In addition, one of the most expected 5G use cases relates a function capable of smoothly connecting embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential Internet-of-things (IoT) devices will reach 204 hundred million up to the year of 2020. An industrial IoT is one of categories of performing a main role enabling a smart city, asset tracking, smart utility, agriculture, and security infrastructure through 5G.
URLLC includes a new service that will change industry through remote control of main infrastructure and an ultra-reliable/available low-latency link such as a self-driving vehicle. A level of reliability and latency is essential to control a smart grid, automatize industry, achieve robotics, and control and adjust a drone.
5G is a means of providing streaming evaluated as a few hundred megabits per second to gigabits per second and may complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such fast speed is needed to deliver TV in resolution of 4K or more (6K, 8K, and more), as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games. A specific application program may require a special network configuration. For example, for VR games, gaming companies need to incorporate a core server into an edge network server of a network operator in order to minimize latency.
Automotive is expected to be a new important motivated force in 5G together with many use cases for mobile communication for vehicles. For example, entertainment for passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect connection of high quality regardless of their locations and speeds. Another use case of an automotive field is an AR dashboard. The AR dashboard causes a driver to identify an object in the dark in addition to an object seen from a front window and displays a distance from the object and a movement of the object by overlapping information talking to the driver. In the future, a wireless module enables communication between vehicles, information exchange between a vehicle and supporting infrastructure, and information exchange between a vehicle and other connected devices (e.g., devices accompanied by a pedestrian). A safety system guides alternative courses of a behavior so that a driver may drive more safely drive, thereby lowering the danger of an accident. The next stage will be a remotely controlled or self-driven vehicle. This requires very high reliability and very fast communication between different self-driven vehicles and between a vehicle and infrastructure. In the future, a self-driven vehicle will perform all driving activities and a driver will focus only upon abnormal traffic that the vehicle cannot identify. Technical requirements of a self-driven vehicle demand ultra-low latency and ultra-high reliability so that traffic safety is increased to a level that cannot be achieved by human being.
A smart city and a smart home/building mentioned as a smart society will be embedded in a high-density wireless sensor network. A distributed network of an intelligent sensor will identify conditions for costs and energy-efficient maintenance of a city or a home. Similar configurations may be performed for respective households. All of temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, real-time HD video may be demanded by a specific type of device to perform monitoring.
Consumption and distribution of energy including heat or gas is distributed at a higher level so that automated control of the distribution sensor network is demanded. The smart grid collects information and connects the sensors to each other using digital information and communication technology so as to act according to the collected information. Since this information may include behaviors of a supply company and a consumer, the smart grid may improve distribution of fuels such as electricity by a method having efficiency, reliability, economic feasibility, production sustainability, and automation. The smart grid may also be regarded as another sensor network having low latency.
Mission critical application (e.g., e-health) is one of 5G use scenarios. A health part contains many application programs capable of enjoying benefit of mobile communication. A communication system may support remote treatment that provides clinical treatment in a faraway place. Remote treatment may aid in reducing a barrier against distance and improve access to medical services that cannot be continuously available in a faraway rural area. Remote treatment is also used to perform important treatment and save lives in an emergency situation. The wireless sensor network based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.
Wireless and mobile communication gradually becomes important in the field of an industrial application. Wiring is high in installation and maintenance cost. Therefore, a possibility of replacing a cable with reconstructible wireless links is an attractive opportunity in many industrial fields. However, in order to achieve this replacement, it is necessary for wireless connection to be established with latency, reliability, and capacity similar to those of the cable and management of wireless connection needs to be simplified. Low latency and a very low error probability are new requirements when connection to 5G is needed.
Logistics and freight tracking are important use cases for mobile communication that enables inventory and package tracking anywhere using a location-based information system. The use cases of logistics and freight typically demand low data rate but require location information with a wide range and reliability.
Referring to
The BSs 200 and the network 300 may be implemented as wireless devices and a specific wireless device may operate as a BS/network node with respect to other wireless devices.
The wireless devices 100a to 100f represent devices performing communication using radio access technology (RAT) (e.g., 5G new RAT (NR)) or LTE) and may be referred to as communication/radio/5G devices. The wireless devices 100a to 100f may include, without being limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device/server 400. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an AR/VR/Mixed Reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter.
In the present disclosure, the wireless devices 100a to 100f may be called user equipments (UEs). A UE may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or a financial device), a security device, a weather/environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field.
The UAV may be, for example, an aircraft aviated by a wireless control signal without a human being onboard.
The VR device may include, for example, a device for implementing an object or a background of the virtual world. The AR device may include, for example, a device implemented by connecting an object or a background of the virtual world to an object or a background of the real world. The MR device may include, for example, a device implemented by merging an object or a background of the virtual world into an object or a background of the real world. The hologram device may include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information, using an interference phenomenon of light generated when two laser lights called holography meet.
The public safety device may include, for example, an image relay device or an image device that is wearable on the body of a user.
The MTC device and the IoT device may be, for example, devices that do not require direct human intervention or manipulation. For example, the MTC device and the IoT device may include smartmeters, vending machines, thermometers, smartbulbs, door locks, or various sensors.
Here, the radio communication technologies implemented in the wireless devices in the present disclosure may include narrowband internet-of-things (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of low power wide area network (LPWAN) technology, may be implemented in specifications such as LTE Cat NB1 and/or LTE Cat NB2, and may not be limited to the above-mentioned names. Additionally and/or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and be called by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of the various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and may not be limited to the above-mentioned names. Additionally and/or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may include at least one of ZigBee, Bluetooth, and/or LPWAN which take into account low-power communication, and may not be limited to the above-mentioned names. For example, ZigBee technology may generate personal area networks (PANs) associated with small/low-power digital communication based on various specifications such as IEEE 802.15.4 and may be called various names.
The medical device may be, for example, a device used for the purpose of diagnosing, treating, relieving, curing, or preventing disease. For example, the medical device may be a device used for the purpose of diagnosing, treating, relieving, or correcting injury or impairment. For example, the medical device may be a device used for the purpose of inspecting, replacing, or modifying a structure or a function. For example, the medical device may be a device used for the purpose of adjusting pregnancy. For example, the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for procedure.
The security device may be, for example, a device installed to prevent a danger that may arise and to maintain safety. For example, the security device may be a camera, a closed-circuit TV (CCTV), a recorder, or a black box.
The FinTech device may be, for example, a device capable of providing a financial service such as mobile payment. For example, the FinTech device may include a payment device or a point of sales (POS) system.
The weather/environment device may include, for example, a device for monitoring or predicting a weather/environment.
The wireless devices 100a to 100f may be connected to the network 300 via the BSs 200. An AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network. Although the wireless devices 100a to 100f may communicate with each other through the BSs 200/network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs 200/network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V)/vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.
Wireless communication/connections 150a, 150b and 150c may be established between the wireless devices 100a to 100f and/or between wireless device 100a to 100f and BS 200 and/or between BSs 200. Herein, the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as uplink/downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)), etc. The wireless devices 100a to 100f and the BSs 200/the wireless devices 100a to 100f may transmit/receive radio signals to/from each other through the wireless communication/connections 150a, 150b and 150c. For example, the wireless communication/connections 150a, 150b and 150c may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/de-mapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.
Referring to
The first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally further include one or more transceivers 106 and/or one or more antennas 108. The processor(s) 102 may control the memory(s) 104 and/or the transceiver(s) 106 and may be configured to/adapted to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. For example, the processor(s) 102 may process information within the memory(s) 104 to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s) 106. The processor(s) 102 may receive radio signals including second information/signals through the transceiver(s) 106 and then store information obtained by processing the second information/signals in the memory(s) 104. The memory(s) 104 may be connected to the processor(s) 102 and may store a variety of information related to operations of the processor(s) 102. For example, the memory(s) 104 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 102 or for performing the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. Herein, the processor(s) 102 and the memory(s) 104 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 106 may be connected to the processor(s) 102 and transmit and/or receive radio signals through one or more antennas 108. Each of the transceiver(s) 106 may include a transmitter and/or a receiver. The transceiver(s) 106 may be interchangeably used with radio frequency (RF) unit(s). In the present disclosure, the first wireless device 100 may represent a communication modem/circuit/chip.
The second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally further include one or more transceivers 206 and/or one or more antennas 208. The processor(s) 202 may control the memory(s) 204 and/or the transceiver(s) 206 and may be configured to/adapted to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. For example, the processor(s) 202 may process information within the memory(s) 204 to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s) 206. The processor(s) 202 may receive radio signals including fourth information/signals through the transceiver(s) 106 and then store information obtained by processing the fourth information/signals in the memory(s) 204. The memory(s) 204 may be connected to the processor(s) 202 and may store a variety of information related to operations of the processor(s) 202. For example, the memory(s) 204 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 202 or for performing the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. Herein, the processor(s) 202 and the memory(s) 204 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 206 may be connected to the processor(s) 202 and transmit and/or receive radio signals through one or more antennas 208. Each of the transceiver(s) 206 may include a transmitter and/or a receiver. The transceiver(s) 206 may be interchangeably used with RF unit(s). In the present disclosure, the second wireless device 200 may represent a communication modem/circuit/chip.
Hereinafter, hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY) layer, media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP) layer). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs) and/or one or more service data unit (SDUs) according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure.
The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 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 the one or more processors 102 and 202. descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software and the firmware or software may be configured to/adapted to include the modules, procedures, or functions. Firmware or software configured to/adapted to perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and/or a set of commands.
The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands. The one or more memories 104 and 204 may be configured by read-only memories (ROMs), random access memories (RAMs), electrically erasable programmable read-only memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof. The one or more memories 104 and 204 may be located at the interior and/or exterior of the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.
The one or more transceivers 106 and 206 may transmit user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, to one or more other devices. The one or more transceivers 106 and 206 may receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, from one or more other devices. For example, the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.
The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to/adapted to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208. In the present disclosure, the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).
The one or more transceivers 106 and 206 may convert received radio signals/channels, etc., from RF band signals into baseband signals in order to process received user data, control information, radio signals/channels, etc., using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals/channels, etc., processed using the one or more processors 102 and 202 from the base band signals into the RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and/or filters. For example, the transceivers 106 and 206 can up-convert OFDM baseband signals to a carrier frequency by their (analog) oscillators and/or filters under the control of the processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and/or filters under the control of the transceivers 102 and 202.
In the implementations of the present disclosure, a UE may operate as a transmitting device in uplink (UL) and as a receiving device in downlink (DL). In the implementations of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. Hereinafter, for convenience of description, it is mainly assumed that the first wireless device 100 acts as the UE, and the second wireless device 200 acts as the BS. For example, the processor(s) 102 connected to, mounted on or launched in the first wireless device 100 may be configured to/adapted to perform the UE behavior according to an implementation of the present disclosure or control the transceiver(s) 106 to perform the UE behavior according to an implementation of the present disclosure. The processor(s) 202 connected to, mounted on or launched in the second wireless device 200 may be configured to/adapted to perform the BS behavior according to an implementation of the present disclosure or control the transceiver(s) 206 to perform the BS behavior according to an implementation of the present disclosure.
In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.
The wireless device may be implemented in various forms according to a use-case/service (refer to
Referring to
The additional components 140 may be variously configured according to types of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power unit/battery, input/output (I/O) unit (e.g., audio I/O port, video I/O port), a driving unit, and a computing unit. The wireless devices 100 and 200 may be implemented in the form of, without being limited to, the robot (100a of
In
Referring to
The first wireless device 100 may include at least one transceiver, such as a transceiver 106, and at least one processing chip, such as a processing chip 101. The processing chip 101 may include at least one processor, such a processor 102, and at least one memory, such as a memory 104. The memory 104 may be operably connectable to the processor 102. The memory 104 may store various types of information and/or instructions. The memory 104 may store a software code 105 which implements instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may control the processor 102 to perform one or more protocols. For example, the software code 105 may control the processor 102 may perform one or more layers of the radio interface protocol.
The second wireless device 200 may include at least one transceiver, such as a transceiver 206, and at least one processing chip, such as a processing chip 201. The processing chip 201 may include at least one processor, such a processor 202, and at least one memory, such as a memory 204. The memory 204 may be operably connectable to the processor 202. The memory 204 may store various types of information and/or instructions. The memory 204 may store a software code 205 which implements instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may control the processor 202 to perform one or more protocols. For example, the software code 205 may control the processor 202 may perform one or more layers of the radio interface protocol.
Referring to
A UE 100 includes a processor 102, a memory 104, a transceiver 106, one or more antennas 108, a power management module 110, a battery 1112, a display 114, a keypad 116, a subscriber identification module (SIM) card 118, a speaker 120, and a microphone 122.
The processor 102 may be configured to/adapted to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The processor 102 may be configured to/adapted to control one or more other components of the UE 100 to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. Layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include ASIC, other chipset, logic circuit and/or data processing device. The processor 102 may be an application processor. The processor 102 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). An example of the processor 102 may be found in SNAPDRAGON™ series of processors made by Qualcomm®, EXYNOS™ series of processors made by Samsung®, A series of processors made by Apple®, HELIO™ series of processors made by MediaTek®, ATOM™ series of processors made by Intel® or a corresponding next generation processor.
The memory 104 is operatively coupled with the processor 102 and stores a variety of information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium and/or other storage device. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The modules can be stored in the memory 104 and executed by the processor 102. The memory 104 can be implemented within the processor 102 or external to the processor 102 in which case those can be communicatively coupled to the processor 102 via various means as is known in the art.
The transceiver 106 is operatively coupled with the processor 102, and transmits and/or receives a radio signal. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include baseband circuitry to process radio frequency signals. The transceiver 106 controls the one or more antennas 108 to transmit and/or receive a radio signal.
The power management module 110 manages power for the processor 102 and/or the transceiver 106. The battery 112 supplies power to the power management module 110.
The display 114 outputs results processed by the processor 102. The keypad 116 receives inputs to be used by the processor 102. The keypad 16 may be shown on the display 114.
The SIM card 118 is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). It is also possible to store contact information on many SIM cards.
The speaker 120 outputs sound-related results processed by the processor 102. The microphone 122 receives sound-related inputs to be used by the processor 102.
The frame structure shown in
Referring to
Table 1 shows the number of OFDM symbols per slot Nslotsymb, the number of slots per frame Nframe,uslot, and the number of slots per subframe Nsubframe,uslot for the normal CP, according to the subcarrier spacing βf=2u*15 KHz.
Table 2 shows the number of OFDM symbols per slot Nslotsymb, the number of slots per frame Nframe,uslot, and the number of slots per subframe Nsubframe,uslot for the extended CP, according to the subcarrier spacing βf=2u*15 KHz.
A slot includes plural symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g., subcarrier spacing) and carrier, a resource grid of Nsize,ugrid,x*NRBsc subcarriers and Nsubframe,usymb OFDM symbols is defined, starting at common resource block (CRB) Nstart,ugrid indicated by higher-layer signaling (e.g., RRC signaling), where Nsize,ugrid,x is the number of resource blocks (RBs) in the resource grid and the subscript x is DL for downlink and UL for uplink. NRBsc is the number of subcarriers per RB. In the 3GPP based wireless communication system, NRBsc is 12 generally. There is one resource grid for a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL). The carrier bandwidth Nsize,ugrid for subcarrier spacing configuration u is given by the higher-layer parameter (e.g., RRC parameter). Each element in the resource grid for the antenna port p and the subcarrier spacing configuration u is referred to as a resource element (RE) and one complex symbol may be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index/representing a symbol location relative to a reference point in the time domain. In the 3GPP based wireless communication system, an RB is defined by 12 consecutive subcarriers in the frequency domain. In the 3GPP NR system, RBs are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with ‘point A’ which serves as a common reference point for resource block grids. In the 3GPP NR system, PRBs are defined within a bandwidth part (BWP) and numbered from 0 to NsizeBWP,i−1, where i is the number of the bandwidth part. The relation between the physical resource block nPRB in the bandwidth part i and the common resource block nCRB is as follows: nPRB=nCRB+NsizeBWP,i, where NsizeBWP,i is the common resource block where bandwidth part starts relative to CRB 0. The BWP includes a plurality of consecutive RBs. A carrier may include a maximum of N (e.g., 5) BWPs. A UE may be configured with one or more BWPs on a given component carrier. Only one BWP among BWPs configured to the UE can active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.
The NR frequency band may be defined as two types of frequency range, i.e., FR1 and FR2. The numerical value of the frequency range may be changed. For example, the frequency ranges of the two types (FR1 and FR2) may be as shown in Table 3 below. For ease of explanation, in the frequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”, FR2 may mean “above 6 GHz range,” and may be referred to as millimeter wave (mmW).
As mentioned above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHZ, etc.) or more included in FR1 may include an unlicensed band. Unlicensed bands may be used for a variety of purposes, for example for communication for vehicles (e.g., autonomous driving).
In the present disclosure, the term “cell” may refer to a geographic area to which one or more nodes provide a communication system, or refer to radio resources. A “cell” as a geographic area may be understood as coverage within which a node can provide service using a carrier and a “cell” as radio resources (e.g., time-frequency resources) is associated with bandwidth which is a frequency range configured by the carrier. The “cell” associated with the radio resources is defined by a combination of downlink resources and uplink resources, for example, a combination of a DL component carrier (CC) and a UL CC. The cell may be configured by downlink resources only, or may be configured by downlink resources and uplink resources. Since DL coverage, which is a range within which the node is capable of transmitting a valid signal, and UL coverage, which is a range within which the node is capable of receiving the valid signal from the UE, depends upon a carrier carrying the signal, the coverage of the node may be associated with coverage of the “cell” of radio resources used by the node. Accordingly, the term “cell” may be used to represent service coverage of the node sometimes, radio resources at other times, or a range that signals using the radio resources can reach with valid strength at other times. In CA, two or more CCs are aggregated. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. CA is supported for both contiguous and non-contiguous CCs. When CA is configured, the UE only has one RRC connection with the network. At RRC connection establishment/re-establishment/handover, one serving cell provides the NAS mobility information, and at RRC connection re-establishment/handover, one serving cell provides the security input. This cell is referred to as the primary cell (PCell). The PCell is a cell, operating on the primary frequency, in which the UE either performs the initial connection establishment procedure or initiates the connection re-establishment procedure. Depending on UE capabilities, secondary cells (SCells) can be configured to form together with the PCell a set of serving cells. An SCell is a cell providing additional radio resources on top of special cell (SpCell). The configured set of serving cells for a UE therefore always consists of one PCell and one or more SCells. For dual connectivity (DC) operation, the term SpCell refers to the PCell of the master cell group (MCG) or the primary SCell (PSCell) of the secondary cell group (SCG). An SpCell supports PUCCH transmission and contention-based random access, and is always activated. The MCG is a group of serving cells associated with a master node, comprised of the SpCell (PCell) and optionally one or more SCells. The SCG is the subset of serving cells associated with a secondary node, comprised of the PSCell and zero or more SCells, for a UE configured with DC. For a UE in RRC_CONNECTED not configured with CA/DC, there is only one serving cell comprised of the PCell. For a UE in RRC_CONNECTED configured with CA/DC, the term “serving cells” is used to denote the set of cells comprised of the SpCell(s) and all SCells. In DC, two MAC entities are configured in a UE: one for the MCG and one for the SCG.
In the present disclosure, “RB” denotes a radio bearer, and “H” denotes a header. Radio bearers are categorized into two groups: DRBs for user plane data and SRBs for control plane data. The MAC PDU is transmitted/received using radio resources through the PHY layer to/from an external device. The MAC PDU arrives to the PHY layer in the form of a transport block.
In the PHY layer, the uplink transport channels UL-SCH and RACH are mapped to their physical channels physical uplink shared channel (PUSCH) and physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to physical downlink shared channel (PDSCH), physical broadcast channel (PBCH) and PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to physical uplink control channel (PUCCH), and downlink control information (DCI) is mapped to physical downlink control channel (PDCCH). A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCH is transmitted by a BS via a PDSCH based on a DL assignment.
Referring to
The CU may be functionally split into a CU-control plane (CU-CP) and at least one CU-user plane (CU-UP).
The CU-CP may be a logical node hosting an RRC and a control plane part of a PDCP protocol of the CU for a gNB. As illustrated, the CU-CP is connected to the DU through F1-C interface. The CU-CP terminates an E1 interface connected with the CU-UP and the F1-C interface connected with the DU.
The CU-UP may be a logical node hosting a user plane part of the PDCP protocol of the CU for a gNB, and the user plane part of the PDCP protocol and a SDAP protocol of the CU for a gNB. As illustrated, the CU-UP is connected to the DU through F1-U interface, and is connected to the CU-CP through the E1 interface. The CU-UP terminates the E1 interface connected with the CU-CP and the F1-U interface connected with the DU.
In CU CP-UP split structure, the following properties may hold:
According to various embodiments, each IAB node may comprise a set of functions including one or more distributed units (DUs), a central unit (CU) and/or potentially other functions, as well as the IAB donor.
In a deployment, the IAB donor can be split according to these functions, which can all be either collocated or non-collocated. Also, some of the functions presently associated with the IAB donor may eventually be moved outside of the IAB donor in case it becomes evident that the functions do not perform IAB-specific tasks.
The IAB donor 701 may be connected to the IAB node 711, 713 and 715 via wireless backhaul link (hereinafter, the terms “wireless backhaul link” and “wireless backhaul channel” can be used interchangeably), and may communicate with the IAB node 711, 713 and/or 715 via the wireless backhaul link. For example, DUs of the IAB donor 701 may be used to communicate with the IAB nodes 711, 713 and/or 715 via wireless backhaul link. Each of the IAB node 711 and 715 may communicate with a UE served by itself via wireless access link (hereinafter, the term “wireless access link and wireless access channel can be used interchangeably). Further, the IAB donor 701 may be a parent node for the IAB node 711, 713 and 715, and the IAB node 711, 713 and 715 may be a child node for the IAB donor 701. The definition of the parent node and the child node will be described later.
The IAB node 713 may be connected to IAB node 721 and 723 via wireless backhaul link, and may communicate with the IAB node 721 and/or 723 via wireless backhaul link. The IAB node 721 may communicate with a UE served by itself via wireless access link. Further, the IAB node 713 may be a parent node for the IAB node 721 and 723, and the IAB node 721 and 723 may be a child node for the IAB node 713.
The IAB nodes 711, 713 and 715 may directly communicate with IAB donor 701 via wireless backhaul link. Therefore, the distance between the IAB donor 701 and each of the IAB nodes 711, 713 and 715 may be expressed as 1-hop distance. The IAB donor 701 may be 1-hop parent node for the IAB nodes 711, 713 and 715, and the IAB nodes 711, 713 and 715 may be 1-hop child node for the IAB donor 701.
The IAB nodes 721 and 723 may communicate with the IAB donor 701 via a first wireless backhaul link and a second wireless backhaul link. The first wireless backhaul link may be a wireless backhaul link between i) the IAB node 713 ii) the IAB nodes 721 and/or 723. The second wireless backhaul link may be a wireless backhaul link between the IAB node 713 and the IAB donor 701. Therefore, the distance between the IAB donor 701 and each of the IAB nodes 721 and 723 may be expressed as 2-hop distance. The IAB donor 701 may be 2-hop parent node for the IAB nodes 721 and 723, and the IAB nodes 721 and 723 may be 2-hop child node for the IAB donor 701. In a similar way, N-hop distance may be defined between arbitrary IAB nodes (including or not including IAB donor), and thus, N-hop parent node and N-hop child node may also be defined.
Referring to
IAB-MT may refer to an IAB node function that terminates the Uu interface to the parent node. IAB-DU may refer to a gNB-DU functionality supported by the IAB node to terminate the access interface to UEs and next-hop IAB nodes, and/or to terminate the F1 protocol to the gNB-CU functionality on the IAB donor.
The direction toward the child node may be referred to as downstream while the direction toward the parent node may be referred to as upstream. Further, a backhaul link between an IAB node and a parent node for the IAB node may be referred to as upward backhaul link for the IAB node. A backhaul link between an IAB node and a child node for the IAB node may be referred to as downward backhaul link for the IAB node. A backhaul link for an IAB node may comprise at least one of an upward backhaul link for the IAB node, or a downward backhaul link for the IAB node.
The IAB-node may have redundant routes to the IAB-donor CU.
For IAB-nodes operating in SA-mode, NR dual connectivity (DC) may be used to enable route redundancy in the backhaul (BH) by allowing the IAB-MT to have concurrent BH RLC links with two parent nodes. That is, an IAB node may establish a connection with a parent node which may be a master node (MN) and another parent node which may be a secondary node (SN), and utilize radio resources provided by the two parent nodes.
The parent nodes have to be connected to the same IAB-donor CU-CP, which controls the establishment and release of redundant routes via these two parent nodes. The parent nodes together with the IAB-donor CU may obtain the roles of the IAB-MT's master node and secondary node. The NR DC framework (e.g. MCG/SCG-related procedures) may be used to configure the dual radio links with the parent nodes.
An IAB node may perform a radio link monitoring (RLM) for detecting a problem on a backhaul connection established between the IAB node and a parent node for the IAB node. The IAB node may detect a radio link failure (RLF) on the backhaul connection (i.e., BH RLF) towards the parent node based on detecting the problem.
To detect the problem on the backhaul connection towards the parent node, the IAB node shall:
Upon receiving N311 consecutive “in-sync” indications for the SpCell from lower layers while T310 is running, the IAB node shall:
In this case, the IAB node maintains the backhaul connection without explicit signalling, i.e., the IAB node maintains the entire radio resource configuration.
Periods in time where neither “in-sync” nor “out-of-sync” is reported by L1 (i.e., physical layer) do not affect the evaluation of the number of consecutive “in-sync” or “out-of-sync” indications.
To detect an RLF, the IAB node shall:
For example, an IAB node may detect an RLF on a backhaul connection towards a parent node based on a number of consecutive out-of-sync events detected on the backhaul connection reaching an RLF threshold during a pre-defined or configured time period.
After detecting a BH RLF, the IAB node may transmit a BH RLF indication to one or more childe nodes. Various types of BH RLF indications may be defined, which may include:
Referring to
On each backhaul link, the BAP PDUs may be carried by backhaul (BH) radio link control (RLC) channels. Multiple BH RLC channels can be configured on each BH link to allow traffic prioritization and QoS enforcement. The BH-RLC-channel mapping for BAP PDUs may be performed by the BAP entity on each IAB-node and the IAB-donor.
Referring to
In
The PHY layer may belong to layer 1 (L1). The PHY layer offers information transfer services to MAC sublayer and higher layers. The PHY layer offers to the MAC sublayer transport channels. Data between the MAC sublayer and the PHY layer is transferred via the transport channels. Between different PHY layers, i.e., between a PHY layer of a transmission side and a PHY layer of a reception side, data is transferred via the physical channels.
The MAC sublayer may belong to layer 2 (L2). The main services and functions of the MAC sublayer include mapping between logical channels and transport channels, multiplexing/de-multiplexing of MAC service data units (SDUs) belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), priority handling between UEs by means of dynamic scheduling, priority handling between logical channels of one UE by means of logical channel prioritization (LCP), etc. The MAC sublayer offers to the radio link control (RLC) sublayer logical channels.
The RLC sublayer belong to L2. The RLC sublayer supports three transmission modes, i.e. transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM), in order to guarantee various quality of services (QOS) required by radio bearers. The main services and functions of the RLC sublayer depend on the transmission mode. For example, the RLC sublayer provides transfer of upper layer PDUs for all three modes, but provides error correction through ARQ for AM only. In LTE/LTE-A, the RLC sublayer provides concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer) and re-segmentation of RLC data PDUs (only for AM data transfer). In NR, the RLC sublayer provides segmentation (only for AM and UM) and re-segmentation (only for AM) of RLC SDUs and reassembly of SDU (only for AM and UM). That is, the NR does not support concatenation of RLC SDUs. The RLC sublayer offers to the packet data convergence protocol (PDCP) sublayer RLC channels.
The PDCP sublayer belong to L2. The main services and functions of the PDCP sublayer for the user plane include header compression and decompression, transfer of user data, duplicate detection, PDCP PDU routing, retransmission of PDCP SDUs, ciphering and deciphering, etc. The main services and functions of the PDCP sublayer for the control plane include ciphering and integrity protection, transfer of control plane data, etc.
A radio resource control (RRC) layer belongs to L3. The RRC layer is only defined in the control plane. The RRC layer controls radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the BS. The main services and functions of the RRC layer include broadcast of system information related to AS and NAS, paging, establishment, maintenance and release of an RRC connection between the UE and the network, security functions including key management, establishment, configuration, maintenance and release of radio bearers, mobility functions, QoS management functions, UE measurement reporting and control of the reporting, NAS message transfer to/from NAS from/to UE.
In other words, the RRC layer controls logical channels, transport channels, and physical channels in relation to the configuration, reconfiguration, and release of radio bearers. A radio bearer refers to a logical path provided by L1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAP sublayer) for data transmission between a UE and a network. Setting the radio bearer means defining the characteristics of the radio protocol layer and the channel for providing a specific service, and setting each specific parameter and operation method. Radio bearer may be divided into signaling RB (SRB) and data RB (DRB). The SRB is used as a path for transmitting RRC messages in the control plane, and the DRB is used as a path for transmitting user data in the user plane.
An RRC state indicates whether an RRC layer of the UE is logically connected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in the RRC connected state (RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE). In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced. RRC_INACTIVE may be used for various purposes. For example, the massive machine type communications (MMTC) UEs can be efficiently managed in RRC_INACTIVE. When a specific condition is satisfied, transition is made from one of the above three states to the other.
A predetermined operation may be performed according to the RRC state. In RRC_IDLE, public land mobile network (PLMN) selection, broadcast of system information (SI), cell re-selection mobility, core network (CN) paging and discontinuous reception (DRX) configured by NAS may be performed. The UE shall have been allocated an identifier (ID) which uniquely identifies the UE in a tracking area. No RRC context stored in the BS.
In RRC_CONNECTED, the UE has an RRC connection with the network (i.e. E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is also established for UE. The UE AS context is stored in the network and the UE. The RAN knows the cell which the UE belongs to. The network can transmit and/or receive data to/from UE. Network controlled mobility including measurement is also performed.
Most of operations performed in RRC_IDLE may be performed in RRC_INACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging is performed in RRC_INACTIVE. In other words, in RRC_IDLE, paging for mobile terminated (MT) data is initiated by core network and paging area is managed by core network. In RRC_INACTIVE, paging is initiated by NG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN. Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRX for RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, in RRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established for UE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knows the RNA which the UE belongs to.
NAS layer is located at the top of the RRC layer. The NAS control protocol performs the functions, such as authentication, mobility management, security control.
Further, each of the IAB donor, IAB node 1 and IAB node 2 may comprise a BAP layer/sublayer. The main service and functions of the BAP sublayer may include:
The IAB-DU's IP traffic may be routed over the wireless backhaul via the BAP sublayer. In downstream direction, IP packets may be encapsulated by the BAP sublayer at the IAB-donor, and de-encapsulated at the destination IAB-node. In upstream direction, the upper layer traffic may be encapsulated at the IAB-node, and de-encapsulated at the IAB-donor.
On the BAP sublayer, packets may be routed based on the BAP routing ID, which is carried in the BAP header. The BAP header may be added to the packet when the packet arrives from upper layers, and the packet may be stripped off when the packet has reached a destination node of the packet. The selection of the packet's BAP routing ID may be configured by the IAB-donor. The BAP routing ID may comprise/consists of BAP address (e.g., destination Id for a destination node) and BAP path ID related to a routing path. The BAP address may indicate the destination node of the packet on the BAP sublayer, and the BAP path ID may indicate the routing path the packet should follow to the destination. For the purpose of routing, each IAB-node may be further configured with a designated BAP address.
On each hop of the packet's path, the IAB-node may inspect the packet's BAP address in the routing header to determine if the packet has reached its destination, i.e., matches the IAB-node's BAP address. In case the packet has not reached the destination, the IAB-node may determine the next hop backhaul link, referred to as egress link, based on the BAP routing ID carried in the packet header and a routing configuration the IAB-node received from the IAB-donor.
The IAB-node may also select the BH RLC channel on the designated egress link. For packets arriving from upper layers, the selection of the BH RLC channel may be configured by the CU, and it is based on upper layer traffic specifiers. Since each BH RLC channel is configured with a QoS code point or priority level, RLC-channel selection may facilitate traffic-specific prioritization and QoS enforcement on the BH. For F1-U traffic, it may be possible to map each GTP-U tunnel to a dedicated BH RLC channel or to aggregate multiple GTP-U tunnels into one common BH RLC channel.
When packets are routed from one BH link to another, the BH RLC channel on the egress BH link may be determined based on the mapping configuration between ingress BH RLC channels and egress BH RLC channels provided by the IAB-donor.
In upstream direction, the IAB-donor CU may configure the IAB-node with mappings between upstream F1- and non-F1-traffic originated at the IAB-node, and the appropriate BAP routing ID and Backhaul RLC channel. A specific mapping may be configured:
Multiple mappings can contain the same Backhaul RLC channel and/or BAP routing ID.
These configurations may be received via F1AP. During IAB-node integration, before F1AP is established, a default BH RLC channel and a default BAP routing ID may be configured via RRC, which are used for all upper layer traffic.
In downstream direction, traffic mapping may occur internal to the IAB-donor.
Routing on BAP sublayer may use the BAP routing ID, which is configured by the IAB-donor. For the routing ID, the flow control information may be provided in the flow control feedback. The BAP routing ID may comprise/consist of BAP address and BAP path ID. A length of the routing ID may be 20 bits, in which leftmost 10bits may indicate BAP address and rightmost 10bits may indicate BAP path ID. The BAP address may be used for the following purposes:
For packets arriving from a prior hop, the determination of the next-hop node may be based on a routing configuration provided by the IAB-donor CU via F1AP signalling. The routing configuration may contain the mapping between the BAP routing ID carried in the packet's BAP header and the next-hop node's BAP address, as specified in table 5:
The IAB-node may resolve the next-hop BAP address to a physical backhaul link. For this purpose, IAB-donor CU may provide IAB-node with its child-node's BAP address in a UE-associated FIAP message and its parent-node's BAP address in RRC signalling. The IAB-node can receive multiple routing configurations with the same destination BAP address but different BAP path IDs. These routing configurations may resolve to the same or different egress BH links. In case the BH link has RLF, the IAB-node may select another BH link based on routing entries with the same destination BAP address, i.e., by disregarding the BAP path ID. In this manner, a packet can be delivered via an alternative path in case the indicated path is not available.
When routing a packet from an ingress to an egress BH link, the IAB-node may derive the egress RLC-channel on the egress BH link through an FIAP-configured mapping from the RLC channel used on the ingress BH link. The RLC channel IDs used for ingress and egress BH RLC channels may be generated by the IAB-donor CU. Since the RLC channel ID only has link-local scope, the mapping configurations may also include the BAP addresses of prior and next hop, as specified in table 6:
The IAB-node may resolve the BH RLC channel IDs from logical channel IDs based on the configuration by the IAB-donor. For RLC channels in downstream direction, the RLC channel ID may be included in the FIAP configuration of the RLC channel. For RLC channels in upstream direction, the RLC channel ID may be included in the RRC configuration of the corresponding logical channel.
On the IAB-node, the BAP sublayer may contain one BAP entity at the MT function and a separate BAP entity at the DU function. On the IAB-donor DU, the BAP sublayer may contain only one BAP entity. Each BAP entity may have a transmitting part and a receiving part. The transmit part of the BAP entity may have a corresponding receiving part of a BAP entity at the IAB node or IAB donor DU across the backhaul link.
The receiving part on the BAP entity may deliver BAP PDUs to the collocated transmitting part on the BAP entity. Alternatively, the receiving part may deliver BAP SDUs to the collocated transmitting part. When passing BAP SDUs, the receiving part may remove the BAP header and the transmitting part may add the BAP header with the same BAP routing ID as carried on the BAP PDU header prior to removal. Passing BAP SDUs in this manner may be therefore functionally equivalent to passing BAP PDUs, in implementation.
The transmitting part of the BAP entity on the IAB-MT can receive BAP SDUs from upper layers and BAP Data Units from the receiving part of the BAP entity on the IAB-DU of the same IAB-node, and construct BAP Data PDUs as needed. The transmitting part of the BAP entity on the IAB-DU can receive BAP Data Units from the receiving part of the BAP entity on the IAB-MT of the same IAB node and construct BAP Data PDUs as needed. The transmitting part of the BAP entity on the IAB-donor DU can receive BAP SDUs from upper layers.
Upon receiving a BAP SDU from upper layers, the transmitting part of the BAP entity shall:
When the BAP entity has a BAP Data PDU to transmit, the transmitting part of the BAP entity shall:
Data buffering on the transmitting part of the BAP entity, e.g., until RLC-AM entity has received an acknowledgement, may be performed. In case of BH RLF, the transmitting part of BAP entity may reroute the BAP Data PDUs, which has not been acknowledged by lower layer before the backhaul RLF, to an alternative path.
Upon receiving a BAP Data PDU from lower layer (i.e. ingress BH RLC channel), the receiving part of the BAP entity shall:
When a BAP PDU that contains reserved or invalid values or contains a BAP address which is not included in the configured BH routing information received, the BAP entity shall discard the received BAP PDU.
Meanwhile, when an IAB node is connected to dual parents in DC, the IAB node may detect a BH RLF on one or more of the parents, and determine to transmit a BH RLF detection indication to one or more child nodes. The IAB node should decide when the IAB node should send the BH RLF detection indication to child node(s). Following options can be considered:
With option 1, child nodes do not know the occurrence of the parent's BH failure until the both CGs of the parents fail. This means that the child nodes are transparent to the occurrence of the parent's BH failure until the both CGs of the parents fail, which in turn requires the parent node to take proper actions upon the BH failure, such as local re-routing (i.e., routing path switching) by the parent node so that the child nodes can remain unaffected from the parent's BH failure. The child node can trigger local re-routing only after both CGs of the parents fail, because BH RLF detection indication is triggered only after both CGs of the parents fail. If the IAB node that detects the BH failure cannot perform local re-routing due to its capability limitation or configuration from its donor node, the child node may be informed about the BH failure only when both backhauls for the parents fail. This is too late information, and until then traffics from the child node could be stalled in the failed backhaul.
In contrast, with option 2, child nodes can be informed earlier about the occurrence of its parent's BH RLF, compared to the option 1. Such earlier failure notification in the option 1 may allow the child node to take proactive actions such as local re-routing, if possible. However, if the IAB node that detects a BH failure already triggers local re-routing upon the BH failure, the child node's local re-routing may be redundant and incur unnecessary changes of routing path of traffics.
The two options may have their merits but they also have problems/limitations as mentioned above.
In the present disclosure, if an IAB node connected with multiple parents detects a BH failure to its parent node, the IAB node may decide whether to perform local routing. If the IAB node decide to perform local re-routing towards another parent node, the IAB node does not send a BH RLF indication (BH RLF detection) to its child node. If the IAB node decides not to perform local re-routing towards another node, the IAB node may send a BH RLF indication to its child node. If the IAB node is not capable of performing local re-routing towards another node, the IAB node may send a BH RLF indication to its child node.
The determination on whether to perform local re-routing may be based on pre-configuration or configuration by other network node, e.g., donor node or neighbour node.
The determination on whether to perform local re-routing may be made per child node. For example, if the IAB node performs local re-routing only for a subset of child nodes but not for the rest of child nodes, the IAB node may transmit the BH RLF indication to the rest of child nodes. The BH RLF indication may indicate the occurrence of BH RLF.
Upon local re-routing, the IAB node may change its backhaul path (next hop) for packet routing from the backhaul where BH failure is detected to a new backhaul path where no BH failure is detected. An IAB node can perform local re-routing if the IAB node is connected with two or more parents (i.e., in case two or more backhauls are established with the IAB node).
Referring to
In step S1403, the first wireless device may perform a transmission via a routing path to the second wireless device.
In step S1405, the first wireless device may detect a problem of a backhaul connection between the first wireless device and the second wireless device.
In step S1407, the first wireless device may determine whether the routing path can be switched from the second wireless device to the third wireless device based on detecting the problem.
In step S1409, based on a determination that the routing path cannot be switched, the first wireless device may transmit a notification of the problem to a fourth wireless device.
In step S1411, based on a determination that the routing path can be switched, the first wireless device may switch the routing path from the second wireless device to the third wireless device without transmitting the notification of the problem to fourth wireless device.
According to various embodiments, the second wireless device and the third wireless device may be a parent node for the first wireless device. The fourth wireless device may be a child node for the first wireless device providing a backhaul connection to the fourth wireless device.
According to various embodiments, the problem may comprise at least one of: a radio link failure (RLF) on the backhaul connection: a beam failure detection on the backhaul connection; a transmission delay over the backhaul connection exceeding a threshold; packet retransmissions exceeding a threshold: an amount of queued packets over the backhaul connection exceeding a threshold: or a quality of the backhaul connection being lower than a threshold.
According to various embodiments, whether the routing path can be switched from the second wireless device to the third wireless device may be determined based on at least one of a pre-configuration, a configuration by a donor node or a configuration by a parent node.
According to various embodiments, the routing path may be related to one or more data flows.
For example, the one or more data flows may comprise all data flows passing through the backhaul connection between the first wireless device and the second wireless device.
For another example, the one or more data follows may comprise one or more first data flows and one or more second data flows. In this case:
According to various embodiments, the notification of the problem may comprise information informing the one or more first data flows for which routing path cannot be switched.
According to various embodiments, the one or more first data flows and the one or more second data flows may be associated with the fourth wireless device.
According to various embodiments, the one or more first data flows may be associated with the fourth wireless device and the one or more second data flows may be associated with a fifth wireless device which is a child node for the first wireless device. In this case, based on a determination that the routing path for the one or more second data flows cannot be switched, the first wireless device may transmit the notification of the problem to the fifth wireless device.
According to various embodiments, the notification of the problem may be included in a backhaul adaptation protocol (BAP) protocol data unit (PDU).
According to various embodiments, a wireless device may detect a backhaul problem and inform the problem to one or more other devices. More specifically, the wireless device may detect a BH RLF. The wireless device may determine whether to send a BH RLF indication (BH RLF detection indication) based on an execution of local re-routing by the wireless device. The wireless device may perform local re-routing if the wireless device is configured by a donor to perform local re-routing upon detecting the BH RLF. The wireless device may construct the BH RLF indication. The wireless device may send the BH RLF indication to at least one child node connected to the wireless device.
In
Referring to
In step S1503, the fourth wireless device may perform a transmission via a first routing path to the first wireless device. The transmission may be routed from the first wireless to the second wireless device over a second routing path.
In step S1505, a problem of a backhaul connection between the first wireless device and the second wireless device occurs.
Based on the second routing path being unable to be switched from the second wireless device to the third wireless device after the problem occurs, in step S1507, the fourth wireless device may receive a notification of the problem from the first wireless device. In step S1509, the fourth wireless device may switch the first routing path from the first wireless device to another wireless device based on receiving the notification of the problem.
Based on the second routing path being able to be switched from the second wireless device to the third wireless device after the problem occurs, in step S1511, the fourth wireless device may keep performing the transmission via the first routing path to the first wireless device without receiving the notification of the problem from the first wireless device. The transmission may continuously be routed from the first wireless to the second wireless device over the second routing path.
In
Referring to
If the node 4 is capable of re-routing and hence is capable of triggering local re-routing upon detection of BH RLF based on its autonomous decision or donor's configuration, the node 4 does not send BH RLF indication (BH RLF detection indication) to its child node 6 and 7. In such a case the child node may remain transparent to the event of the BH RLF. That is, the child node may not be aware of the event of the BH RLF.
In contrast, if the node 4 is not capable of re-routing or the node 4 is configured not to trigger local re-routing upon detection of BH RLF, the node 4 may send BH RLF indication to its child node 6 and 7. Then the child node can, upon reception of the indication, take an action such as local re-routing or triggering mobility, if possible.
For example, upon reception of BH RLF indication from node 4, the node 6 may perform local re-routing towards node 6 from node 4.
For example, upon reception of BH RLF indication from node 4, the node 7 may perform a mobility towards other node not necessarily shown in
In RRC_CONNECTED, the UE performs Radio Link Monitoring (RLM) in the active BWP based on reference signals (SSB/CSI-RS) and signal quality thresholds configured by the network. SSB-based RLM is based on the SSB associated to the initial DL BWP and can only be configured for the initial DL BWP and for DL BWPs containing the SSB associated to the initial DL BWP. Besides, SSB-based RLM can be also performed based on the non-cell defining SSB, if configured for RedCap UEs. For other DL BWPs, RLM can only be performed based on CSI-RS. In case of DAPS handover, the UE continues the detection of radio link failure at the source cell until the successful completion of the random access procedure to the target cell.
The UE declares Radio Link Failure (RLF) when one of the following criteria are met:
After RLF is declared, the UE:
When RLF occurs at the IAB BH link, the same mechanisms and procedures are applied as for the access link. This includes BH RLF detection and RLF recovery.
The IAB-DU can transmit a BH RLF detection indication to its child nodes in the following cases:
Upon reception of the BH RLF detection indication, the child node may perform local rerouting for upstream traffic, if possible, over an available BH link.
If the IAB-DU has transmitted a BH RLF detection indication to a child node due to an RLF condition on the collocated IAB-MT's parent link, and the collocated IAB-MT's subsequent RLF recovery is successful, the IAB-DU may transmit a BH RLF recovery indication to this child node.
If the IAB-DU has transmitted a BH RLF detection indication to a child node due to the reception of a BH RLF detection indication by the collocated IAB-MT, and the collocated IAB-MT receives a BH RLF recovery indication, the IAB-DU may also transmit a BH RLF recovery indication to this child node.
Upon reception of the BH RLF recovery indication, the child node reverts the actions triggered by the reception of the previous BH RLF detection indication.
In case the RRC re-establishment procedure fails, the IAB-node may transmit a BH RLF indication to its child nodes. The BH RLF detection indication, BH RLF recovery indication and BH RLF indication are transmitted as BAP Control PDUs.
Furthermore, the method in perspective of the first wireless device described above in
More specifically, the first wireless device comprises at least one transceiver, at least processor, and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations.
The operations comprise: establishing a respective backhaul connection with a second wireless device and a third wireless device; performing a transmission via a routing path to the second wireless device; detecting a problem of a backhaul connection between the first wireless device and the second wireless device; determining whether the routing path can be switched from the second wireless device to the third wireless device based on detecting the problem; and based on a determination that the routing path cannot be switched, transmitting a notification of the problem to a fourth wireless device.
Furthermore, the method in perspective of the first wireless device described above in
More specifically, at least one computer readable medium (CRM) stores instructions that, based on being executed by at least one processor, perform operations comprising: establishing a respective backhaul connection with a second wireless device and a third wireless device; performing a transmission via a routing path to the second wireless device; detecting a problem of a backhaul connection between the first wireless device and the second wireless device: determining whether the routing path can be switched from the second wireless device to the third wireless device based on detecting the problem; and based on a determination that the routing path cannot be switched, transmitting a notification of the problem to a fourth wireless device.
Furthermore, the method in perspective of the first wireless device described above in
More specifically, an apparatus configured to/adapted to operate in a wireless communication system (e.g., wireless device/UE) comprises at least processor, and at least one computer memory operably connectable to the at least one processor. The at least one processor is configured to/adapted to perform operations comprising: establishing a respective backhaul connection with a second wireless device and a third wireless device; performing a transmission via a routing path to the second wireless device; detecting a problem of a backhaul connection between the first wireless device and the second wireless device: determining whether the routing path can be switched from the second wireless device to the third wireless device based on detecting the problem; and based on a determination that the routing path cannot be switched, transmitting a notification of the problem to a fourth wireless device.
Furthermore, the method in perspective of the fourth wireless device described above in
More specifically, the fourth wireless device comprises at least one transceiver, at least processor, and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations.
The operations comprise: establishing a backhaul connection with a first wireless device having a respective backhaul connection with a second wireless device and a third wireless device; performing a transmission via a first routing path to the first wireless device—the transmission being routed from the first wireless to the second wireless device over a second routing path: based on the second routing path being unable to be switched from the second wireless device to the third wireless device after a problem of a backhaul connection between the first wireless device and the second wireless device occurs, receiving a notification of the problem from the first wireless device; and switching the first routing path from the first wireless device to another wireless device based on receiving the notification of the problem. The present disclosure can have various advantageous effects.
For example, a node capable of performing a local re-routing when BH RLF occurs does not transmit a BH RLF detection indication to its child node so that unnecessary local re-routing by the child node and unnecessary BH RLF signaling can be avoided.
Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and/or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.
Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method. Other implementations are within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0141208 | Oct 2021 | KR | national |
This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2022/016164, filed on Oct. 21, 2022, which claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2021-0141208, filed on Oct. 21, 2021, the contents of which are all incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/016164 | 10/21/2022 | WO |
