Communication device and communication method

Abstract

This communication device comprises a generation unit for generating error detection data, and an addition unit for adding redundant data including the error detection data to one or a plurality of encoded sequences generated through encoding processing. The error detection data is used to detect errors in the one or plurality of encoded sequences. The generation unit generates error detection data of different lengths according to a prescribed condition.

Description

[Technical Field]

[0001] This disclosure relates to communication devices and communication methods. [Background technology]

[0002] In wireless communication, for a communication device to accurately transmit data to another communication device, it is necessary to transmit various types of data in addition to user data. For example, a communication device may transmit redundant data, such as error detection data, in addition to user data. By using redundant data for error detection, it becomes possible to transmit data with very high accuracy. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2007 / 069406 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] From the perspective of reducing the amount of redundant data transmitted and improving frequency utilization efficiency, shorter redundant data lengths are desirable. On the other hand, from the perspective of reducing data retransmissions due to misjudgments by error detection functions and improving frequency utilization efficiency, it is necessary to increase the length of redundant data to improve the accuracy of error detection, etc. However, the length of redundant data has not been given much consideration until now, and communication devices have not necessarily been able to achieve high frequency utilization efficiency.

[0005] Therefore, this disclosure proposes a communication device and a communication method that can achieve high frequency utilization efficiency.

[0006] It should be noted that the above-mentioned problems or objectives are merely one of several problems or objectives that can be solved or achieved by the multiple embodiments disclosed herein. [Means for solving the problem]

[0007] To solve the above problems, one form of communication device according to the present disclosure comprises a generation unit that generates error detection data, and an assignment unit that assigns redundant data including the error detection data to one or more coded sequences generated by coding processing, wherein the error detection data is used for error detection of the one or more coded sequences, and the generation unit generates error detection data of different lengths according to predetermined conditions. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the use of the loss-of-character correction coding scheme in communication. [Figure 2] This figure shows an example configuration of a communication system according to the embodiment of this disclosure. [Figure 3] This figure shows an example configuration of a management device according to an embodiment of this disclosure. [Figure 4] This figure shows an example of the configuration of a base station according to the present disclosure. [Figure 5] This figure shows an example of the configuration of a relay station according to the present disclosure. [Figure 6] This figure shows an example configuration of a terminal device according to the embodiments of this disclosure. [Figure 7] This diagram shows an overview of the signal processing of the transmitting communication device. [Figure 8] This diagram shows an overview of the signal processing of the receiving communication device. [Figure 9] This figure shows an example of loss correction coding. [Figure 10] This figure shows an example of redundant data added to an encoded sequence. [Figure 11] This figure shows an example of the communication processing sequence in this embodiment. [Figure 12] This is a schematic diagram of the redundant data generation process using CRC. [Figure 13] This is a diagram showing the packet structure. [Figure 14]This is a diagram showing the operation of an erasure correction code when a single communication device communicates using a plurality of communication channels. [Figure 15] This is a diagram showing the operation of an erasure correction code when a single communication device communicates using a plurality of communication channels.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. In each of the following embodiments, the same reference numerals are given to the same parts, and redundant descriptions are omitted.

[0010] Also, in this specification and the drawings, there are cases where a plurality of components having substantially the same functional configuration are distinguished by attaching different numbers after the same reference numeral. For example, a plurality of configurations having substantially the same functional configuration are distinguished as terminal devices 401, 402, and 403 as necessary. However, when it is not necessary to particularly distinguish each of a plurality of components having substantially the same functional configuration, only the same reference numeral is attached. For example, when it is not necessary to particularly distinguish the terminal devices 401, 402, and 403, they are simply referred to as the terminal device 40.

[0011] One or more of the embodiments (including examples and modifications) described below can each be implemented independently. On the other hand, at least some of the plurality of embodiments described below may be implemented in appropriate combination with at least some of other embodiments. These plurality of embodiments may include different novel features. Therefore, these plurality of embodiments can contribute to solving different objects or problems and can exhibit different effects.

[0012] <<1. Overview>> Radio access technologies (RATs) such as LTE (Long Term Evolution) and NR (New Radio) are being considered by 3GPP (3rd Generation Partnership Project). LTE and NR are types of cellular communication technologies that enable mobile communication for terminal devices by arranging multiple base stations in a cell-like structure. In this case, a single base station may manage multiple cells.

[0013] In the following explanation, "LTE" includes LTE-A (LTE-Advanced), LTE-A Pro (LTE-Advanced Pro), and E-UTRA (Evolved Universal Terrestrial Radio Access). Similarly, "NR" includes NRAT (New Radio Access Technology) and FE-UTRA (Further E-UTRA). In the following explanation, cells supporting LTE are referred to as LTE cells, and cells supporting NR are referred to as NR cells.

[0014] NR is the next generation (fifth generation) of radio access technology (RAT) after LTE. NR is a radio access technology that can support a variety of use cases, including eMBB (Enhanced Mobile Broadband), mMTC (Massive Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications). NR is being developed with the aim of creating a technical framework that addresses the usage scenarios, requirements, and deployment scenarios in these use cases.

[0015] The frequency bands used in NR (or the frequency bands expected to be used in B5G (Beyond 5th Generation) and 6G (6th Generation)) are millimeter waves (30-300 GHz) and terahertz waves (300 GHz-3 THz). Compared to those used in LTE, these frequency bands have lower diffraction properties and are more susceptible to shadowing and blocking.

[0016] The forward error correction code (FEC), implemented in the physical layer, is an encoding scheme that assumes bit-level error correction using likelihood information. When packets are lost due to blocking or shadowing, the likelihood information obtained on the receiving end becomes 0. Therefore, when using high-frequency bandwidths for communication as described above, it is necessary to consider using error correction codes other than bit-level forward error correction codes.

[0017] There exists a forward error correction code that corrects errors at the unit level, where an information sequence formed by multiple bits (hereinafter also called a symbol or bit block) is treated as a single unit (the unit here is a symbol or coded sequence). The configuration in which this code is used for wireless communication is also called network coding. When using this coding method, the transmitting communication device generates parity using bitwise operations with multiple information systems. The receiving communication device attempts to decode using the transmitted information sequence and parity. One such coding method is the vanishing error correction coding method.

[0018] Figure 1 is a schematic diagram of the use of loss-of-symbol correction coding in communication. In this diagram, the transmitting side generates one parity (F in the diagram) from multiple information sequences (AE in the diagram). Error detection data (error detection data in the diagram) is added to each information sequence. The receiving side performs error detection on each received information sequence. Subsequently, only the correctly received coded sequences are inserted into the decoder, and the lost symbols (D in the diagram) are restored.

[0019] Generally, when adding error detection capabilities to an information sequence, additional overhead (hereinafter also referred to as redundant data or error detection data) with error detection functionality is added to the information sequence to be detected. In Cyclic Redundancy Check (CRC), a widely used error detection function, there is a positive proportional relationship between error detection accuracy and overhead length. It is also known that the length of the information sequence for which errors can be detected changes depending on the degree of the generator polynomial used in CRC coding. Therefore, longer redundant data is required to achieve higher detection accuracy.

[0020] In this respect, conventional communication devices assign a fixed length of error detection data regardless of the conditions. For example, conventional communication devices assign a fixed length of CRC regardless of the length of the encoded sequence or the condition of the communication channel. Therefore, under certain conditions, the length of the error detection data (e.g., CRC) becomes excessive. In other words, when the length of the encoded sequence is short, or when the communication channel is in good condition with few errors occurring (for example, when the error rate is not expected to be very high), the communication device will use a CRC with more overhead length than necessary. This reduces frequency utilization efficiency.

[0021] Therefore, in this embodiment, this problem is solved by the following means.

[0022] The communication device of this embodiment (e.g., a base station and terminal device) generates error detection data (e.g., a value generated by CRC processing) for error detection in one or more coded sequences generated by loss correction coding processing, and adds redundant data including the error detection data to one or more coded sequences. At this time, the communication device generates error detection data of different lengths according to predetermined conditions. For example, the communication device generates error detection data of a length determined based on the length of one or more coded sequences. Alternatively, the communication device generates error detection data of a length determined based on the error rate estimated when one or more coded sequences are transmitted. As a result, the communication device of this embodiment can add redundant data of an appropriate length to the coded sequences, thereby achieving high frequency utilization efficiency. Furthermore, the length of the data in this disclosure may be rephrased as the size of the data.

[0023] Having outlined the basics of this embodiment, the communication system according to this embodiment will now be described in detail.

[0024] <<2. Communication System Configuration>> The configuration of communication system 1 will be explained in detail below, with reference to the diagrams.

[0025] <2-1. Overall Configuration of the Communication System> Figure 2 shows an example configuration of a communication system 1 according to an embodiment of the present disclosure. The communication system 1 comprises a management device 10, a base station 20, a relay station 30, and a terminal device 40. The communication system 1 provides a wireless network capable of mobile communication to a user through the coordinated operation of each wireless communication device constituting the communication system 1. The wireless network in this embodiment is composed of, for example, a wireless access network and a core network. In this embodiment, a wireless communication device is a device having wireless communication functionality, and in the example in Figure 2, this refers to the base station 20, the relay station 30, and the terminal device 40.

[0026] The communication system 1 may include multiple management devices 10, base stations 20, relay stations 30, and terminal devices 40. In the example in Figure 2, the communication system 1 includes management devices 101, 102, etc. as management devices 10, and base stations 201, 202, etc. as base stations 20. The communication system 1 also includes relay stations 301, 302, etc. as relay stations 30, and terminal devices 401, 402, 403, etc. as terminal devices 40.

[0027] It should be noted that the devices in the diagram can be considered as devices in a logical sense. In other words, some of the devices in the diagram may be implemented as virtual machines (VMs), containers, Docker, etc., and these may be implemented on the same physical hardware.

[0028] Furthermore, communication system 1 may support radio access technologies (RAT: Radio Access Technology) such as LTE (Long Term Evolution) and NR (New Radio). LTE and NR are types of cellular communication technologies that enable mobile communication of terminal devices by arranging multiple base stations in a cell-like structure.

[0029] Furthermore, the wireless access method used by communication system 1 is not limited to LTE or NR, but may also be other wireless access methods such as W-CDMA (Wideband Code Division Multiple Access) or cdma2000 (Code Division Multiple Access 2000).

[0030] Furthermore, the base stations or relay stations constituting communication system 1 may be ground stations or non-ground stations. Non-ground stations may be satellite stations or aircraft stations. If the non-ground station is a satellite station, communication system 1 may be a bent-pipe (transparent) type mobile satellite communication system.

[0031] In this embodiment, a ground station (also called a ground base station) refers to a base station (including relay stations) installed on the ground. Here, "ground" is a broad term that includes not only land but also underground, on water, and underwater. In the following explanation, the term "ground station" may be replaced with "gateway."

[0032] Note that LTE base stations are sometimes referred to as eNodeB (Evolved Node B) or eNB. Similarly, NR base stations are sometimes referred to as gNodeB or gNB. In both LTE and NR, terminal equipment (also called mobile stations or terminals) is sometimes referred to as UE (User Equipment). Note that terminal equipment is a type of communication device and is also called a mobile station or terminal.

[0033] In this embodiment, the concept of a communication device includes not only portable mobile devices (terminal devices) such as mobile terminals, but also devices installed on structures or mobile objects. Structures or mobile objects themselves may be considered communication devices. Furthermore, the concept of a communication device includes not only terminal devices, but also base stations and relay stations. A communication device is a type of processing device and information processing device. A communication device can also be referred to as a transmitting device or a receiving device.

[0034] The configuration of each device constituting communication system 1 will be described in detail below. Note that the configurations of each device shown below are merely examples. The configuration of each device may differ from those shown below.

[0035] <2-2. Configuration of the control device> Next, the configuration of the control device 10 will be described.

[0036] The management device 10 is a device that manages the wireless network. For example, the management device 10 is a device that manages the communication of the base station 20. The management device 10 may also be a device that functions as an MME (Mobility Management Entity). The management device 10 may also be a device that functions as an AMF (Access and Mobility Management Function) and / or an SMF (Session Management Function). Of course, the functions of the management device 10 are not limited to MME, AMF, and SMF. The management device 10 may also be a device that functions as an NSSF (Network Slice Selection Function), AUSF (Authentication Server Function), PCF (Policy Control Function), or UDM (Unified Data Management). Furthermore, the management device 10 may also be a device that functions as an HSS (Home Subscriber Server).

[0037] Furthermore, the management device 10 may also have gateway functionality. For example, the management device 10 may function as an S-GW (Serving Gateway) or a P-GW (Packet Data Network Gateway). In addition, the management device 10 may also function as a UPF (User Plane Function).

[0038] The core network consists of multiple network functions, each of which may be aggregated in a single physical device or distributed across multiple physical devices. In other words, the management device 10 can be distributed across multiple devices. Furthermore, this distributed distribution may be controlled to be performed dynamically. The base station 20 and the management device 10 form a single network and provide wireless communication services to the terminal device 40. The management device 10 is connected to the internet, and the terminal device 40 can use various services provided via the internet through the base station 20.

[0039] Note that the management device 10 does not necessarily have to be a device that constitutes the core network. For example, suppose the core network is a W-CDMA (Wideband Code Division Multiple Access) or cdma2000 (Code Division Multiple Access 2000) core network. In this case, the management device 10 may be a device that functions as an RNC (Radio Network Controller).

[0040] Figure 3 shows an example configuration of a management device 10 according to an embodiment of the present disclosure. The management device 10 comprises a communication unit 11, a storage unit 12, and a control unit 13. Note that the configuration shown in Figure 3 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the management device 10 may be implemented by statically or dynamically distributing them across multiple physically separated configurations. For example, the management device 10 may be composed of multiple server devices.

[0041] The communication unit 11 is a communication interface for communicating with other devices. The communication unit 11 may be a network interface or an equipment connection interface. For example, the communication unit 11 may be a LAN (Local Area Network) interface such as a NIC (Network Interface Card), or a USB interface consisting of a USB (Universal Serial Bus) host controller, USB port, etc. Furthermore, the communication unit 11 may be a wired interface or a wireless interface. The communication unit 11 functions as a communication means for the management device 10. The communication unit 11 communicates with the base station 20, etc., according to the control of the control unit 13.

[0042] The memory unit 12 is a data read / write storage device such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), flash memory, or hard disk. The memory unit 12 functions as a storage means for the management device 10. The memory unit 12 stores, for example, the connection status of the terminal device 40. For example, the memory unit 12 stores the RRC (Radio Resource Control) status, ECM (EPS Connection Management) status, or 5G System CM (Connection Management) status of the terminal device 40. The memory unit 12 may also function as a home memory that stores the location information of the terminal device 40.

[0043] The control unit 13 is a controller that controls each part of the management device 10. The control unit 13 is implemented by a processor such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), or GPU (Graphics Processing Unit). For example, the control unit 13 is implemented by the processor executing various programs stored in the internal storage device of the management device 10 using RAM (Random Access Memory) or the like as a working area. The control unit 13 may also be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). CPUs, MPUs, GPUs, ASICs, and FPGAs can all be considered controllers.

[0044] <2-3. Base Station Configuration> Next, we will explain the configuration of base station 20.

[0045] The base station 20 is a wireless communication device that communicates wirelessly with the terminal device 40. The base station 20 may be configured to communicate wirelessly with the terminal device 40 via a relay station 30, or it may be configured to communicate wirelessly with the terminal device 40 directly.

[0046] Base station 20 is a type of communication device. More specifically, base station 20 is a device equivalent to a wireless base station (Base Station, Node B, eNB, gNB, etc.) or a wireless access point. Base station 20 may also be a wireless relay station. Base station 20 may also be an optical extension device called an RRH (Remote Radio Head) or RU (Radio Unit). Base station 20 may also be a receiving station such as an FPU (Field Pickup Unit). Base station 20 may also be an IAB (Integrated Access and Backhaul) donor node or IAB relay node that provides wireless access lines and wireless backhaul lines using time division multiplexing, frequency division multiplexing, or spatial division multiplexing.

[0047] The wireless access technology used by base station 20 may be cellular communication technology or wireless LAN technology. Of course, the wireless access technology used by base station 20 is not limited to these and may be other wireless access technologies. For example, the wireless access technology used by base station 20 may be LPWA (Low Power Wide Area) communication technology. Of course, the wireless communication used by base station 20 may be wireless communication using millimeter waves. Furthermore, the wireless communication used by base station 20 may be wireless communication using radio waves, or wireless communication using infrared or visible light (optical wireless).

[0048] Base station 20 may be capable of NOMA (Non-Orthogonal Multiple Access) communication with terminal device 40. Here, NOMA communication refers to communication (transmission, reception, or both) using non-orthogonal resources. Base station 20 may also be capable of NOMA communication with other base stations 20.

[0049] Furthermore, the base stations 20 may be able to communicate with each other via base station-core network interfaces (e.g., NG Interface, S1 Interface, etc.). These interfaces may be either wired or wireless. In addition, the base stations may be able to communicate with each other via inter-base station interfaces (e.g., Xn Interface, X2 Interface, S1 Interface, F1 Interface, etc.). These interfaces may be either wired or wireless.

[0050] Furthermore, the concept of a base station includes not only donor base stations but also relay base stations (also called relay stations). For example, a relay base station may be any one of the following: an RF Repeater, a Smart Repeater, or an Intelligent Surface. Also, the concept of a base station includes not only structures equipped with base station functions but also equipment installed on those structures.

[0051] Structures include buildings such as skyscrapers, houses, transmission towers, train stations, airports, ports, office buildings, school buildings, hospitals, factories, commercial facilities, and stadiums. The concept of structures also includes not only buildings but also non-building structures such as tunnels, bridges, dams, walls, and steel columns, as well as equipment such as cranes, gates, and wind turbines. Furthermore, the concept of structures includes not only structures on land (in the narrow sense of the ground) or underground, but also structures on water such as piers and megafloats, and underwater structures such as oceanographic observation equipment. A base station can be rephrased as an information processing device.

[0052] Base station 20 may be a donor station or a relay station. Furthermore, base station 20 may be a fixed station or a mobile station. A mobile station is a wireless communication device (e.g., a base station) configured to be mobile. In this case, base station 20 may be a device installed on a mobile object or the mobile object itself. For example, a relay station with mobility can be considered a base station 20 as a mobile station. Additionally, devices that are inherently mobile and equipped with base station functions (or at least some of the functions of a base station), such as vehicles, UAVs (Unmanned Aerial Vehicles) represented by drones, and smartphones, also qualify as base station 20 as a mobile station.

[0053] Here, the moving object may be a mobile device such as a smartphone or mobile phone. Furthermore, the moving object may be a moving object that moves on land (on the ground in the narrow sense) (for example, a car, bicycle, bus, truck, motorcycle, train, maglev train, etc.) or a moving object that moves underground (for example, inside a tunnel) (for example, a subway).

[0054] Furthermore, the mobile object may be a mobile object that moves on the water (for example, a passenger ship, cargo ship, hovercraft, or other vessel) or a mobile object that moves underwater (for example, a submersible, submarine, or unmanned underwater vehicle).

[0055] Furthermore, the moving object may be a moving object that moves within the atmosphere (for example, an aircraft such as an airplane, airship, or drone).

[0056] Furthermore, base station 20 may be a ground base station (ground station) installed on the ground. For example, base station 20 may be a base station located on a structure on the ground, or a base station installed on a mobile device moving on the ground. More specifically, base station 20 may be an antenna installed on a structure such as a building and a signal processing device connected to that antenna. Of course, base station 20 may be the structure or mobile device itself. "Ground" refers to ground in a broad sense, including not only land (ground in the narrow sense) but also underground, on water, and underwater. Note that base station 20 is not limited to a ground base station. For example, if communication system 1 is a satellite communication system, base station 20 may be an aircraft station. From the perspective of a satellite station, an aircraft station located on Earth is a ground station.

[0057] Furthermore, base station 20 is not limited to a ground station. Base station 20 may also be a non-ground base station (non-ground station) capable of floating in the air or space. For example, base station 20 may be an aircraft station or a satellite station.

[0058] A satellite station is a satellite station capable of floating outside the atmosphere. A satellite station may be a device mounted on a space-based mobile vehicle such as an artificial satellite, or it may be the space-based mobile vehicle itself. A space-based mobile vehicle is a mobile vehicle that moves outside the atmosphere. Examples of space-based mobile vehicles include artificial satellites, spacecraft, space stations, probes, and other artificial celestial bodies.

[0059] The satellite serving as the satellite station may be a low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), or highly elliptical orbit (HEO) satellite. Of course, the satellite station may also be equipment mounted on a low Earth orbit satellite, medium Earth orbit satellite, geostationary satellite, or highly elliptical orbit satellite.

[0060] An aircraft station is a radio communication device capable of floating within the atmosphere, such as an aircraft. An aircraft station may be a device mounted on an aircraft, or it may be the aircraft itself. The concept of an aircraft includes not only heavy aircraft such as airplanes and gliders, but also light aircraft such as balloons and airships. Furthermore, the concept of an aircraft includes not only heavy and light aircraft, but also rotary-wing aircraft such as helicopters and autogyros. An aircraft station (or the aircraft on which an aircraft station is mounted) may also be an unmanned aerial vehicle such as a drone.

[0061] The concept of unmanned aerial vehicles (UAS) also includes unmanned aircraft systems (UAS) and tethered UAS. Furthermore, the concept of unmanned aerial vehicles includes lighter than air UAS (LTA) and heavier than air UAS (HTA). In addition, the concept of unmanned aerial vehicles also includes high-altitude UAS platforms (HAPs).

[0062] The coverage size of base station 20 can range from large, like a macrocell, to small, like a picocell. Of course, the coverage size of base station 20 can also be extremely small, like a femtocell. Furthermore, base station 20 may have beamforming capabilities. In this case, base station 20 may form cells or service areas for each beam.

[0063] Figure 4 shows an example configuration of a base station 20 according to the present disclosure. The base station 20 comprises a wireless communication unit 21, a storage unit 22, and a control unit 23. Note that the configuration shown in Figure 4 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the base station 20 may be distributed and implemented across multiple physically separated configurations.

[0064] The wireless communication unit 21 is a signal processing unit for wireless communication with other wireless communication devices (e.g., terminal device 40). The wireless communication unit 21 operates according to the control of the control unit 23. The wireless communication unit 21 supports one or more wireless access methods. For example, the wireless communication unit 21 supports both NR and LTE. In addition to NR and LTE, the wireless communication unit 21 may also support W-CDMA and cdma2000. Furthermore, the wireless communication unit 21 may support automatic retransmission technologies such as HARQ (Hybrid Automatic Repeat reQuest).

[0065] The wireless communication unit 21 comprises a transmission processing unit 211, a reception processing unit 212, and an antenna 213. The wireless communication unit 21 may comprise multiple transmission processing units 211, reception processing units 212, and antennas 213. When the wireless communication unit 21 supports multiple wireless access methods, each part of the wireless communication unit 21 may be configured individually for each wireless access method. For example, the transmission processing unit 211 and the reception processing unit 212 may be configured individually for LTE and NR. The antenna 213 may also consist of multiple antenna elements (e.g., multiple patch antennas). In this case, the wireless communication unit 21 may be configured to be beamforming capable. The wireless communication unit 21 may also be configured to be polarization beamforming capable of using vertical polarization (V polarization) and horizontal polarization (H polarization).

[0066] The transmission processing unit 211 performs the transmission processing of downlink control information and downlink data. For example, the transmission processing unit 211 encodes the downlink control information and downlink data input from the control unit 23 using an encoding method such as block coding, convolutional coding, or turbo coding. Here, encoding may be done using polar coding or LDPC coding (Low Density Parity Check Code). The transmission processing unit 211 then modulates the encoded bits using a predetermined modulation method such as BPSK, QPSK, 16QAM, 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily have to be equidistant. The constellation may be a non-uniform constellation (NUC). The transmission processing unit 211 then multiplexes the modulation symbols and downlink reference signals for each channel and places them in predetermined resource elements. The transmission processing unit 211 then performs various signal processing on the multiplexed signals. For example, the transmission processing unit 211 performs processing such as conversion to the frequency domain using the Fast Fourier Transform, addition of a guard interval (cyclic prefix), generation of a baseband digital signal, conversion to an analog signal, quadrature modulation, upconversion, removal of extraneous frequency components, and power amplification. The signal generated by the transmission processing unit 211 is transmitted from the antenna 213.

[0067] The receiving processing unit 212 processes the uplink signal received via the antenna 213. For example, the receiving processing unit 212 performs down-conversion, removal of unwanted frequency components, amplification level control, quadrature demodulation, conversion to a digital signal, removal of guard intervals (cyclic prefixes), and extraction of frequency domain signals using the Fast Fourier Transform on the uplink signal. Then, the receiving processing unit 212 separates the uplink channels and uplink reference signals, such as PUSCH (Physical Uplink Shared Channel) and PUCCH (Physical Uplink Control Channel), from the processed signal. The receiving processing unit 212 also demodulates the received signal using modulation schemes such as BPSK (Binary Phase Shift Keying) and QPSK (Quadrature Phase Shift Keying) for the modulation symbols of the uplink channels. The modulation scheme used for demodulation may be 16QAM (Quadrature Amplitude Modulation), 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily need to be equidistant. The constellation may be a non-uniform constellation (NUC). The receiving processing unit 212 then performs decoding on the encoded bits of the demodulated uplink channel. The decoded uplink data and uplink control information are output to the control unit 23.

[0068] Antenna 213 is an antenna device (antenna unit) that converts electric current and radio waves to each other. Antenna 213 may consist of one antenna element (e.g., one patch antenna) or multiple antenna elements (e.g., multiple patch antennas). If antenna 213 consists of multiple antenna elements, the wireless communication unit 21 may be configured to beamform. For example, the wireless communication unit 21 may be configured to generate a directional beam by controlling the directivity of the wireless signal using multiple antenna elements. Antenna 213 may also be a dual-polarization antenna. If antenna 213 is a dual-polarization antenna, the wireless communication unit 21 may use vertical polarization (V polarization) and horizontal polarization (H polarization) when transmitting the wireless signal. The wireless communication unit 21 may then control the directivity of the transmitted wireless signal using vertical polarization and horizontal polarization. Furthermore, the wireless communication unit 21 may transmit and receive spatially multiplexed signals through multiple layers composed of multiple antenna elements.

[0069] The memory unit 22 is a data read / write storage device such as DRAM, SRAM, flash memory, or hard disk. The memory unit 22 functions as a storage means for the base station 20.

[0070] The control unit 23 is a controller that controls various parts of the base station 20. The control unit 23 is implemented by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). For example, the control unit 23 is implemented by the processor executing various programs stored in the memory device inside the base station 20, using RAM (Random Access Memory) or the like as a working area. The control unit 23 may also be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). CPUs, MPUs, ASICs, and FPGAs can all be considered controllers. In addition, the control unit 23 may be implemented by a GPU (Graphics Processing Unit) in addition to, or instead of, a CPU.

[0071] The control unit 23 comprises a receiving unit 231, a transmitting unit 232, an acquisition unit 233, a generation unit 234, an assignment unit 235, and a detection unit 236. Each block constituting the control unit 23 (receiving unit 231 to detection unit 236) is a functional block that indicates the function of the control unit 23. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a single software module implemented in software (including microprograms), or a single circuit block on a semiconductor chip (die). Of course, each functional block may also be a single processor or a single integrated circuit. The control unit 23 may be composed of functional units different from the above-mentioned functional blocks. The method of configuring the functional blocks is arbitrary. Note that the operation of the control unit 23 may be the same as the operation of each block of the control unit of the terminal device 40.

[0072] In some embodiments, the concept of a base station may consist of a collection of multiple physical or logical devices. For example, in this embodiment, a base station may be distinguished into multiple devices such as a BBU (Baseband Unit) and an RU (Radio Unit). The base station may be interpreted as a collection of these multiple devices. Furthermore, a base station may consist of either a BBU or an RU, or both. The BBU and RU may be connected by a predetermined interface (e.g., eCPRI (enhanced Common Public Radio Interface)). Note that RU may be rephrased as RRU (Remote Radio Unit) or RD (Radio DoT). Also, the RU may correspond to a gNB-DU (gNB Distributed Unit) described later. Furthermore, the BBU may correspond to a gNB-CU (gNB Central Unit) described later. Alternatively, the RU may be a radio device connected to a gNB-DU described later. The gNB-CU, gNB-DU, and RU connected to the gNB-DU may be configured to comply with O-RAN (Open Radio Access Network). Furthermore, the RU may be a device formed integrally with an antenna. The antennas of the base station (for example, antennas integrated with the RU) may employ an Advanced Antenna System and support MIMO (e.g., FD-MIMO) and beamforming. Furthermore, the antennas of the base station may have, for example, 64 transmitting antenna ports and 64 receiving antenna ports.

[0073] Furthermore, the antenna mounted on the RU may be an antenna panel composed of one or more antenna elements, and the RU may be equipped with one or more antenna panels. For example, the RU may be equipped with two types of antenna panels, a horizontally polarized antenna panel and a vertically polarized antenna panel, or two types of antenna panels, a right-hand circularly polarized antenna panel and a left-hand circularly polarized antenna panel. In addition, the RU may form and control independent beams for each antenna panel.

[0074] Multiple base stations may be interconnected. One or more base stations may be included in a Radio Access Network (RAN). In this case, the base station may simply be referred to as RAN, RAN node, AN (Access Network), or AN node. In LTE, the RAN is sometimes called EUTRAN (Enhanced Universal Terrestrial RAN). In NR, the RAN is sometimes called NGRAN. In W-CDMA (UMTS), the RAN is sometimes called UTRAN.

[0075] Furthermore, LTE base stations are sometimes referred to as eNodeB (Evolved Node B) or eNB. In this case, EUTRAN includes one or more eNodeBs (eNBs). Similarly, NR base stations are sometimes referred to as gNodeB or gNB. In this case, NGRAN includes one or more gNBs. EUTRAN may also include gNBs (en-gNBs) connected to the core network (EPC) in the LTE communication system (EPS). Likewise, NGRAN may include ng-eNBs connected to the core network 5GC in the 5G communication system (5GS).

[0076] Furthermore, if the base station is an eNB or gNB, it may be referred to as 3GPP Access. If the base station is an Access Point, it may be referred to as Non-3GPP Access. Additionally, the base station may be an optical extension device called an RRH (Remote Radio Head) or RU (Radio Unit). If the base station is a gNB, it may be a combination of the aforementioned gNB-CU and gNB-DU, or it may be either a gNB-CU or a gNB-DU.

[0077] Here, the gNB-CU hosts several upper layers of the Access Stratum (e.g., RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), and PDCP (Packet Data Convergence Protocol)) for communication with the UE. On the other hand, the gNB-DU hosts several lower layers of the Access Stratum (e.g., RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer)). That is, among the messages / information described later, RRC signaling (quasi-static notifications) may be generated by the gNB-CU, while MAC CE and DCI (dynamic notifications) may be generated by the gNB-DU. Alternatively, among the RRC configuration (quasi-static notifications), some configurations, such as IE:cellGroupConfig, may be generated by the gNB-DU, and the remaining configurations may be generated by the gNB-CU. These configurations may be sent and received via the F1 interface described later.

[0078] Furthermore, a base station may be configured to communicate with other base stations. For example, if multiple base stations are eNBs or a combination of eNB and en-gNB, they may be connected via an X2 interface. Also, if multiple base stations are gNBs or a combination of gn-eNB and gNB, they may be connected via an Xn interface. Also, if multiple base stations are a combination of gNB-CU and gNB-DU, they may be connected via the F1 interface described above. Messages / information described later (e.g., RRC signaling, MAC CE (MAC Control Element), or DCI) may be transmitted between multiple base stations, for example, via an X2 interface, Xn interface, or F1 interface.

[0079] Cells provided by a base station are sometimes called serving cells. The concept of a serving cell includes PCell (Primary Cell) and SCell (Secondary Cell). When dual connectivity is configured on the UE (e.g., terminal device 40), the PCell and zero or one or more SCells provided by the MN (Master Node) are sometimes called a Master Cell Group. Examples of dual connectivity include EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5GC, NR-EUTRA Dual Connectivity (NEDC), and NR-NR Dual Connectivity.

[0080] A serving cell may include a PSCell (Primary Secondary Cell, or Primary SCG Cell). When dual connectivity is configured for the UE, the PSCell provided by the SN (Secondary Node), and zero or more SCells, are sometimes referred to as an SCG (Secondary Cell Group). Unless otherwise specified (e.g., PUCCH on SCell), the Physical Uplink Control Channel (PUCCH) is transmitted by both PCells and PSCells, but not by SCells. Similarly, Radio Link Failure is detected by both PCells and PSCells, but not by SCells (and does not need to be detected). Because PCells and PSCells have special roles within a serving cell, they are also called SpCells (Special Cells).

[0081] A single cell may be associated with one downlink component carrier and one uplink component carrier. Furthermore, the system bandwidth corresponding to a single cell may be divided into multiple Bandwidth Parts (BWPs). In this case, one or more BWPs may be configured as UEs, with one BWP being used by the UE as the Active BWP. Additionally, the radio resources available to the terminal device 40 (e.g., frequency band, numerology (subcarrier spacing), slot configuration) may differ for each cell, component carrier, or BWP.

[0082] <2-4. Relay Station Configuration> Next, I will explain the configuration of the relay station 30.

[0083] The relay station 30 is a device that acts as a relay station for a base station. The relay station 30 is a type of base station. The relay station 30 is also a type of information processing device. A relay station can be referred to as a relay base station. The relay station 30 may also be a device called a repeater (e.g., RF Repeater, Smart Repeater, Intelligent Surface).

[0084] The relay station 30 is capable of wireless communication, such as NOMA communication, with the terminal device 40. The relay station 30 relays communication between the base station 20 and the terminal device 40. The relay station 30 may also be configured to enable wireless communication with other relay stations 30 and base stations 20. The relay station 30 may be a ground station or a non-ground station. The relay station 30, together with the base station 20, constitutes a wireless access network (RAN).

[0085] Furthermore, the relay station in this embodiment may be a fixed device, a movable device, or a floating device. Also, the coverage size of the relay station in this embodiment is not limited to a specific size. For example, the cells covered by the relay station may be macrocells, microcells, or small cells.

[0086] Furthermore, the relay station of this embodiment is not limited to the device it is mounted on, as long as the relay function is fulfilled. For example, the relay station may be mounted on a terminal device such as a smartphone, on an automobile, train or rickshaw, on a balloon or airplane or drone, on a traffic light, sign or streetlamp, or on a home appliance such as a television, game console, air conditioner, refrigerator or lighting fixture.

[0087] Furthermore, the configuration of the relay station 30 may be the same as that of the base station 20 described above. For example, the relay station 30 may be a device installed on a mobile device, or it may be the mobile device itself, similar to the base station 20 described above. The mobile device may be a mobile terminal such as a smartphone or mobile phone, as described above. The mobile device may also be a mobile device that moves on land (ground in the narrow sense) or a mobile device that moves underground. Of course, the mobile device may also be a mobile device that moves on water or a mobile device that moves underwater. Furthermore, the mobile device may also be a mobile device that moves within the atmosphere or a mobile device that moves outside the atmosphere. In addition, the relay station 30 may be a ground station device or a non-ground station device. In this case, the relay station 30 may also be an aircraft station or a satellite station.

[0088] Furthermore, the coverage size of the relay station 30 may range from large macrocells to small picocells, similar to the base station 20. Of course, the coverage size of the relay station 30 may also be extremely small, such as femtocells. The relay station 30 may also have beamforming capabilities. In this case, cells or service areas may be formed for each beam of the relay station 30.

[0089] Figure 5 shows an example configuration of a relay station 30 according to the embodiment of this disclosure. The relay station 30 comprises a wireless communication unit 31, a storage unit 32, and a control unit 33. Note that the configuration shown in Figure 5 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the relay station 30 may be distributed and implemented across multiple physically separated configurations.

[0090] The wireless communication unit 31 is a wireless communication interface that communicates wirelessly with other wireless communication devices (e.g., base station 20, terminal device 40, other relay station 30). The wireless communication unit 31 supports one or more wireless access methods. For example, the wireless communication unit 31 supports both NR and LTE. In addition to NR and LTE, the wireless communication unit 31 may also support W-CDMA and cdma2000. The wireless communication unit 31 comprises a transmission processing unit 311, a reception processing unit 312, and an antenna 313. The wireless communication unit 31 may have multiple transmission processing units 311, reception processing units 312, and antennas 313. When the wireless communication unit 31 supports multiple wireless access methods, each part of the wireless communication unit 31 may be configured individually for each wireless access method. For example, the transmission processing unit 311 and the reception processing unit 312 may be configured individually for LTE and NR. The configuration of the transmission processing unit 311, reception processing unit 312, and antenna 313 is the same as the configuration of the transmission processing unit 211, reception processing unit 212, and antenna 213 described above. The wireless communication unit 31 may also be configured to be beamforming-capable, similar to the wireless communication unit 21.

[0091] The memory unit 32 is a data read / write storage device such as DRAM, SRAM, flash memory, or hard disk. The memory unit 32 functions as a storage means for the relay station 30.

[0092] The control unit 33 is a controller that controls each part of the relay station 30. The control unit 33 is implemented by a processor such as a CPU, MPU, or GPU. For example, the control unit 33 is implemented by the processor executing various programs stored in the internal memory of the relay station 30 using RAM or the like as a working area. The control unit 33 may also be implemented by an integrated circuit such as an ASIC or FPGA. CPUs, MPUs, GPUs, ASICs, and FPGAs can all be considered controllers. The operation of the control unit 33 may be the same as the operation of each block (receiving unit 231 to detection unit 236) of the control unit 23 of the base station 20.

[0093] The relay station 30 may also be an IAB relay node. The relay station 30 operates as an IAB-MT (Mobile Termination) for the IAB donor node that provides backhaul, and as an IAB-DU (Distributed Unit) for the terminal device 40 that provides access. The IAB donor node may be, for example, a base station 20, which operates as an IAB-CU (Central Unit).

[0094] <2-5. Terminal Device Configuration> Next, the configuration of the terminal device 40 will be described.

[0095] Terminal device 40 is a wireless communication device that communicates wirelessly with other communication devices such as base station 20 and relay station 30. Terminal device 40 may be, for example, a mobile phone, a smart device (smartphone or tablet), a PDA (Personal Digital Assistant), or a personal computer. Alternatively, terminal device 40 may be a professional camera equipped with communication functions, or a motorcycle or mobile relay vehicle equipped with communication equipment such as an FPU (Field Pickup Unit). Furthermore, terminal device 40 may be an M2M (Machine to Machine) device or an IoT (Internet of Things) device.

[0096] The terminal device 40 may be capable of NOMA communication with the base station 20. Furthermore, the terminal device 40 may use automatic retransmission technology such as HARQ when communicating with the base station 20. The terminal device 40 may be capable of sidelink communication with other terminal devices 40. The terminal device 40 may also use automatic retransmission technology such as HARQ when performing sidelink communication. Furthermore, the terminal device 40 may be capable of NOMA communication even when communicating with other terminal devices 40 (sidelink). Furthermore, the terminal device 40 may be capable of LPWA communication with other communication devices (for example, the base station 20 and other terminal devices 40). Furthermore, the wireless communication used by the terminal device 40 may be millimeter-wave wireless communication. Furthermore, the wireless communication used by the terminal device 40 (including sidelink communication) may be radio wave wireless communication, or infrared or visible light wireless communication (optical wireless).

[0097] Furthermore, the terminal device 40 may be a mobile device. The mobile device is a portable wireless communication device. In this case, the terminal device 40 may be a wireless communication device installed on the mobile device, or it may be the mobile device itself. For example, the terminal device 40 may be a vehicle that moves on roads, such as an automobile, bus, truck, or motorcycle; a vehicle that moves on rails installed on tracks, such as a train; or a wireless communication device mounted on such a vehicle. The mobile device may be a mobile terminal, or a mobile device that moves on land (ground in the narrow sense), underground, on water, or underwater. The mobile device may also be a mobile device that moves within the atmosphere, such as a drone or helicopter, or a mobile device that moves outside the atmosphere, such as an artificial satellite.

[0098] The terminal device 40 may simultaneously connect to and communicate with multiple base stations or multiple cells. For example, if one base station supports a communication area via multiple cells (e.g., pCell, sCell), it is possible to combine these multiple cells using carrier aggregation (CA), dual connectivity (DC), or multi-connectivity (MC) technologies to enable communication between the base station 20 and the terminal device 40. Alternatively, the terminal device 40 can communicate with multiple base stations 20 via cells of different base stations 20 using coordinated multi-point transmission and reception (CoMP) technology.

[0099] Figure 6 shows an example configuration of a terminal device 40 according to the present disclosure. The terminal device 40 comprises a wireless communication unit 41, a storage unit 42, and a control unit 43. Note that the configuration shown in Figure 6 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the terminal device 40 may be distributed and implemented across multiple physically separated configurations.

[0100] The wireless communication unit 41 is a signal processing unit for wireless communication with other wireless communication devices (e.g., base station 20, relay station 30, and other terminal devices 40). The wireless communication unit 41 operates according to the control of the control unit 43. The wireless communication unit 41 comprises a transmission processing unit 411, a reception processing unit 412, and an antenna 413. The configuration of the wireless communication unit 41, transmission processing unit 411, reception processing unit 412, and antenna 413 may be the same as that of the wireless communication unit 21, transmission processing unit 211, reception processing unit 212, and antenna 213 of the base station 20. Furthermore, the wireless communication unit 41 may be configured to be beamforming, similar to the wireless communication unit 21. In addition, the wireless communication unit 41 may be configured to transmit and receive spatially multiplexed signals, similar to the wireless communication unit 21.

[0101] The memory unit 42 is a data read / write storage device such as DRAM, SRAM, flash memory, or hard disk. The memory unit 42 functions as a storage means for the terminal device 40.

[0102] The control unit 43 is a controller that controls various parts of the terminal device 40. The control unit 43 is implemented by a processor such as a CPU or MPU. For example, the control unit 43 is implemented by the processor executing various programs stored in the memory device inside the terminal device 40 using RAM or the like as a working area. The control unit 43 may also be implemented by an integrated circuit such as an ASIC or FPGA. CPU, MPU, ASIC, and FPGA can all be considered as controllers. In addition, the control unit 43 may be implemented by a GPU in addition to, or instead of, the CPU.

[0103] The control unit 43 comprises a receiving unit 431, a transmitting unit 432, an acquisition unit 433, a generation unit 434, an assignment unit 435, and a detection unit 436. Each block constituting the control unit 43 (receiving unit 431 to detection unit 436) is a functional block that indicates the function of the control unit 43. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a single software module implemented in software (including microprograms), or a single circuit block on a semiconductor chip (die). Of course, each functional block may also be a single processor or a single integrated circuit. The control unit 43 may be composed of functional units different from the above-mentioned functional blocks. The method of configuring the functional blocks is arbitrary. The operation of the control unit 43 may be the same as the operation of each block of the control unit 23 of the base station 20.

[0104] <<3. Operation of the Communication System>> Having described the configuration of the communication system 1 of this embodiment, the signal processing of this embodiment will now be described.

[0105] <3-1. Overview of the Communication System's Operation> First, I will explain the overview of the operation of communication system 1.

[0106] <3-1-1. Overview of Signal Processing> Figures 7 and 8 show an overview of the signal processing in this embodiment. Figure 7 shows an overview of the signal processing of the transmitting communication device, and Figure 8 shows an overview of the signal processing of the receiving communication device. Any of the base station 20, relay station 30, and terminal device 40 can be the transmitting or receiving communication device. In this embodiment, the communication device performs encoding and decoding processing using an erasure correction coding scheme on the information sequence to be transmitted and received, processing to add redundant data to the sequence encoded using the erasure correction coding scheme, and processing to generate packets from one or more encoded sequences.

[0107] First, an overview of the transmitting signal processing will be explained with reference to Figure 7. A predetermined signal processing layer within the communication device acquires an information sequence from a higher layer (e.g., the SDAP layer or RRC layer), performs predetermined signal processing (transmitting process 1 shown in Figure 7), and transmits that information sequence (hereinafter also referred to as the transmitted data sequence) to the coding layer (e.g., the PDCP layer). The coding layer performs loss correction coding on the received transmitted data sequence. Subsequently, the communication device adds redundant data to one or more coded sequences. The redundant data includes error detection data for error detection (e.g., the CRC value). At this time, the error detection data will have a different length depending on predetermined conditions. For example, the error detection data will have a length corresponding to the length of one or more coded sequences. Alternatively, the error detection data will have a different length depending on the error rate estimated when one or more coded sequences are transmitted to the receiving communication device. One or more coded sequences, along with the redundant data, are stored in a packet and, after undergoing predetermined signal processing (transmitting process 2 shown in Figure 7), are transmitted to the receiving communication device. At least a portion of the above process may be omitted, or the above process may be performed across multiple devices.

[0108] Next, with reference to Figure 8, an overview of the receiving-side signal processing will be explained. A predetermined signal processing layer within the communication device, upon receiving a packet from the transmitting communication device, performs predetermined signal processing (receiving-side processing 1 shown in Figure 8) and transmits the packet to the decoding layer (e.g., the PDCP layer). The decoding layer extracts one or more coded sequences from the packet and uses error detection data included in the redundant data to perform error detection on one or more coded sequences. The communication device then performs loss correction coding processing on one or more coded sequences. The information sequence generated by the loss correction coding processing undergoes predetermined signal processing (receiving-side processing 2 shown in Figure 8) and is then transmitted to a higher layer. At least a part of the above processing may be omitted, or the above processing may be performed across multiple devices.

[0109] The communication device of this embodiment generates error detection data of different lengths according to predetermined conditions. As a result, the communication device of this embodiment can add redundant data of an appropriate length to the encoded sequence, thereby achieving high frequency utilization efficiency.

[0110] <3-1-2. Encoding Process> The following describes the loss correction coding process. Note that the loss correction decoding process is a corresponding process to the loss correction coding process, so its explanation will be omitted.

[0111] In the loss-of-bit coding process, multiple bit sequences are generated from a single bit sequence. Here, the single bit sequence that becomes the input to the loss-of-bit coding process corresponds to the transmission data sequence described above. In the loss-of-bit coding process, the communication device may divide the output multiple bit sequences into one or more first bit sequences that must be transmitted and one or more second bit sequences that can be decoded without being transmitted. The communication device may then output multiple bit sequences consisting of one or more first bit sequences and one or more third bit sequences selected from the one or more second bit sequences.

[0112] In the disappearance correction coding process, processing is performed using a predetermined error correction coding scheme. Figure 9 shows an example of the disappearance correction coding process. First, the communication device divides one bit sequence (one source bit sequence) into multiple source bit sequences. Then, the communication device generates multiple parity bit sequences by applying error correction coding to the multiple source bit sequences. For example, the communication device generates multiple parity bit sequences by sequentially performing error correction coding on multiple bit sequences, each consisting of two source bit sequences. Then, the communication device generates multiple output bit sequences by adding the multiple parity bit sequences to the multiple source bit sequences. Note that the parity bit sequences added to the multiple source bit sequences do not necessarily have to be all of the generated parity bit sequences. The communication device may add one or more parity bit sequences selected from the multiple parity bit sequences to the multiple source bit sequences.

[0113] Note that the example shown in Figure 11 is merely one example, and the error correction coding process is not limited to the example shown in Figure 11. For example, the error correction coding scheme may be one in which, when a predetermined bit sequence is input, the encoded bit sequence is output instead of just the parity bit sequence.

[0114] The error correction coding scheme used in this embodiment is not limited to Erasure Codes, but may also be an error correction coding scheme belonging to categories such as Rateless Codes or Fountain Codes. Alternatively, the error correction coding scheme used in this embodiment may be an error correction coding scheme that encodes multiple bit sequences by linear synthesis or XOR synthesis.

[0115] Examples of error correction coding schemes that are expected to be used in this embodiment are shown below in (A1) to (A7). Of course, the error correction coding schemes used in this embodiment are not limited to the following examples.

[0116] (A1) Rateless coding (A2) Fountain code (A3)Tornado code (A4)LT codes (Luby Transform Codes) (A5) Raptor code (A6)RaptorQ code (A7) RS Codes (Reed Solomon Codes)

[0117] <3-1-3. Redundant Data> Next, we will discuss redundant data that may be added to one or more encoded sequences.

[0118] Figure 10 shows an example of redundant data added to an encoded sequence. The communication device adds sequence identification data for symbol identification, error detection data for error detection, and redundant data to the encoded sequence generated by the loss correction code. The redundant data may be added to each encoded sequence or to multiple encoded sequences.

[0119] In Figure 10, the sequence identification data stores, for example, an identification number intended to identify the encoded sequence. Here, the identification number may also be called ID (Identification) or SN (Sequence Number). This identification number is data that the receiving communication device uses to determine which encoded sequence on the transmitting side corresponds to the received encoded sequence. Error detection data consists of error detection bits generated by the transmitting communication device based on the encoded sequence. When generating the error detection bits, further encoding processing may be performed on the encoded sequence (for example, CRC).

[0120] <3-1-4. Example of Encoding Procedure> Next, an example of the coding procedure of this embodiment will be described. Figure 11 is a sequence diagram showing an example of the procedure for loss-of-signal correction coding. Note that the procedure example shown in Figure 11 is merely an example, and this embodiment is not limited to this procedure example. Also, although Figure 11 shows downlink communication from base station 20 to terminal device 40, the technology disclosed in this embodiment can also be applied to other communications (for example, uplink communication from terminal device 40 to base station 20). The following describes an example of the coding procedure of this embodiment with reference to the sequence diagram in Figure 11.

[0121] First, the terminal device 40 notifies the base station 20 of the cell to which it is connected of information regarding its terminal capabilities (step S101). This information includes capability information regarding loss-of-signal coding. The terminal device 40 may notify this terminal capability information during or after the initial access procedure. For this notification, at least one of the following physical channels may be used: a Physical Random Access Channel (PRACH), a Physical Uplink Control Channel (PUCCH), and a Physical Uplink Shared Channel (PUSCH).

[0122] The base station 20 notifies terminal devices 40 connected to the cell under its management of quasi-static control information, including information regarding loss-of-signal correction coding (or loss-of-signal correction decoding) (step S102). This quasi-static control information may be cell-specific control information. The base station 20 may notify this quasi-static control information during or after the initial connection procedure. The base station 20 may also notify this control information as part of an RRC procedure, such as RRC Signaling, RRC Configuration, or RRC Reconfiguration. The base station 20 may also periodically notify terminal devices 40 of this control information. At least one of the following physical channels may be used to notify this control information: a Physical Broadcast Channel (PBCH), an Enhanced Physical Downlink Control Channel (EPDCCH), and a Physical Downlink Shared Channel.

[0123] When the terminal device 40 receives quasi-static control information, it sets up the disappearance correction coding (or disappearance correction decoding) based on the disappearance correction coding (or disappearance correction decoding) information contained in the received control information (step S103).

[0124] Subsequently, when downlink communication occurs from the base station 20 to the terminal device 40, the base station 20 transmits dynamic control information to the terminal device 40. Examples of cases in which downlink communication occurs include when the terminal device 40 requests data download (pull) or when push data is generated to the terminal device 40. This dynamic control information may be terminal-specific (UE-specific) control information or terminal group-specific (UE-group-specific) control information. Here, a terminal group is, for example, a group of one or more terminal devices 40 that are the destinations when the downlink communication is multicast or broadcast.

[0125] Furthermore, dynamic control information may include various types of information, such as information about the wireless resources used for downlink communication. For example, dynamic control information may include information about various resources for allocating downlink communication to the target terminal device 40 (terminal device 40 group). More specifically, dynamic control information may include, for example, the following information (1) to (8).

[0126] (1) Frequency resources (e.g., Resource Block, Subcarrier, Subcarrier Group, etc.) (2) Time resources (e.g., subframes, slots, mini-slots, symbols, etc.) (3) Spatial resources (e.g., antenna, antenna port, spatial layer, spatial stream, etc.) (4) Non-orthogonal resources related to specified communications (e.g., NOMA (Non-orthogonal Multiple Access), MUST (Multiuser Superposition Transmission), IDMA (Interleave Division Multiple Access), CDMA (Code Division Multiple Access), etc.) (e.g., power resources, interleaving patterns, scrambling patterns, spreading patterns, etc.) (5) Information regarding the modulation order and the coding rate of the second coding (e.g., MCS (Modulation and Coding Set)) (6) Erasure correction coding method (7) Information regarding the coding rate of loss correction coding (8) Settings related to ARQ / HARQ (e.g., NDI (New Data Indicator), RV (Redundancy Version), etc.)

[0127] Upon receiving this dynamic control information, the terminal device 40 configures itself to prepare for proper reception of downlink communication according to that control information (step S105).

[0128] Next, the base station 20 encodes the downlink communication data to the terminal device 40 using loss-of-signal coding to match the control information notified to the terminal device 40, and adds redundant data to the encoded sequence. Then, the base station 20 generates a packet of a size based on resource information from one or more encoded sequences to which redundant data has been added (step S106). The base station 20 transmits the generated packet to the terminal device 40 (step S107).

[0129] When the terminal device 40 receives data from the base station 20, it performs various processes (reception processing, demodulation processing, and decoding processing), including loss correction decoding processing, according to the settings specified in the control information (step S108). For example, the terminal device 40 recovers one or more coded sequences from the received packet. Then, the terminal device 40 determines whether the recovered coded sequences contain errors. The terminal device 40 then attempts decoding using only the coded sequences that do not contain errors. The terminal device 40 then sends an ACK or NACK to the base station 20 depending on whether the data decoding was successful or unsuccessful. It is also desirable for the terminal device 40 to change the settings for processing related to additional transmission depending on whether the data decoding was successful or unsuccessful. For example, if decoding fails, it is desirable for the terminal device 40 to store the decoding result or data in the process of decoding (coded sequences, etc.) in memory in order to perform retransmission and synthesis including the next received coded sequence. In the example in Figure 11, the terminal device 40 sends a NACK to the base station 20 (step S109).

[0130] Based on the response (ACK / NACK) received from the terminal device 40, the base station 20 performs an additional transmission decision process (step S110). If a NACK is received, the base station 20 prepares to transmit an additional information sequence. This preparation for retransmission includes adding redundancy to the encoded sequence, packetizing based on the notified resource amount of one or more encoded sequences, and selecting radio resources. If an ACK is received from the terminal device 40, it means that the target data was transmitted and received without problems, so the communication proceeds to the next new data.

[0131] The base station 20 proceeds to retransmit or perform downlink communication of new data in accordance with the processing for additional transmission corresponding to the above response (ACK / NACK). To this end, the base station 20 again notifies the target terminal device 40 of dynamic control information and performs downlink communication according to its settings.

[0132] In the example shown in Figure 13, the base station 20 receives a NACK from the terminal device 40 (step S109), and performs processing to send an additional information sequence (step S110), and also notifies the terminal device 40 of dynamic control information again (step S111). Upon receiving this dynamic control information, the terminal device 40 makes settings to prepare for proper reception of downlink communication according to that control information (step S112). The base station 20 performs loss-of-loss coding, adds redundant data, and generates packets for the downlink communication data to the terminal device 40 to match the control information notified to the terminal device 40 (step S113), and then retransmits the packets to the terminal device 40 (step S114).

[0133] Then, the terminal device 40 performs various processes (reception process, demodulation process, and decoding process) including loss correction decoding process according to the settings specified in the control information (step S115). In the example in Figure 11, the terminal device 40 has succeeded in decoding at this point and has sent an ACK back to the base station 20 (step S116).

[0134] Upon receiving the ACK, base station 20 performs additional transmission decision processing (step S117) and then proceeds to the communication of the next new data.

[0135] <3-2. Details of the communication system's operation> Next, the operation of communication system 1 will be described in detail.

[0136] As described above, conventional communication devices add error detection data of a fixed length regardless of the conditions. The communication device of this embodiment achieves high frequency utilization efficiency by enabling the addition of error detection data of an appropriate length to the encoded sequence. The following describes specific methods for achieving this.

[0137] <3-2-1. Method for generating error detection data> First, let's explain how error detection data is generated. Error detection data is generated by the transmitting communication device. For example, if the transmitting communication device is a base station 20, the error detection data is generated by the generation unit 234 of the base station 20. If the transmitting communication device is a terminal device 40, the error detection data is generated by the generation unit 434 of the terminal device 40.

[0138] The following explanation describes a method for generating CRC values ​​as an example of how to assign error detection data. Note that error detection data is not limited to CRC values; other data may be used as error detection data if there is a positive proportional relationship between the length of the error detection data and the detection accuracy.

[0139] CRC is a method that uses division by a polynomial called a generator polynomial on an information sequence and adds the remainder to the information sequence as redundant bits. Figure 12 is a schematic diagram of the redundant data generation process using CRC. When an N-degree polynomial is used as the generator polynomial, the resulting polynomial is f N Let (x) be denoted as such. The generating polynomial may be selected from atomic polynomials, or determined by a combination of polynomials with a large Hamming distance. N (x) can also be represented by a bit string of length N+1. For example, f8(x) = x 8 +x 7 +x 1 +1 can also be represented as [1 1 0 0 0 0 0 1 1]. Furthermore, since the degree of an N-th polynomial is always 1, the most significant bit representation is sometimes omitted in bit representation. In the example in Figure 12, the polynomial f3(x)=x for N=3. 3 +1 is used as the generating polynomial.

[0140] First, the communication device adds N initial bits to the end of the information sequence. The value of the initial value at this time is arbitrary. In the example of FIG. 12, the communication device sets the initial bits as

[0000] . Then, the communication device finds a bit with a value of 1 from the beginning of the information sequence, and performs a unit division of the information sequence and the bits of the generating polynomial with that position as the beginning. After that, the communication device stores the division result at the position where the information sequence was located. The communication device repeats this operation until all the bits of the information sequence become 0. The initial bits when this operation ends, that is, the sum of the initial bits and the remainder obtained by dividing the information sequence by the generating polynomial, becomes the CRC value (error detection data). At the time of decoding, the communication device performs the same processing as the CRC value (error detection data) generation process at the time of transmission on the target received information sequence, and compares whether the CRC value (error detection data) generated in this process is the same as the CRC value (error detection data) attached to the received information sequence. Thereby, the communication device can detect errors in the information sequence.

[0141] There are the following relationships (1) to (4) between the error detection ability of CRC, the degree of the generating polynomial, and the length of the information sequence.

[0142] (1) An N-degree generating polynomial detects all burst errors with a length of N or less. (2) For a burst error with a length of M = N + 1, the ratio of undetected errors is 2 -(N-1) is. (3) For a burst error with a length of M > N + 1, the ratio of undetected errors is 2 -N is. (4) An N-degree generating polynomial detects all single errors and double errors if the length T of the information sequence satisfies T ≤ 2 N - 1.

[0143] There are also theorems regarding the error detection ability of CRC, the degree of the generating polynomial, and the length of the information sequence, but they are omitted here. From this, it can be seen that based on the error detection rate to be achieved, the redundant length given by CRC can be designed according to the outlook of the error rate of the information sequence and the length of the information sequence.

[0144] In disappearance correction coding, error detection functionality is assigned to each coded sequence. The length of the coded sequence is determined by prior information before the disappearance correction coding is performed, but this prior information is a dynamic value that fluctuates depending on the channel conditions and the length and resource size of the information sequence received from the higher layer. Therefore, it can be said that using a single generator polynomial for error detection is not effective.

[0145] <3-2-2. Determining the length of error detection data> The above explains how to generate error detection data. Next, we will explain the process for changing the length of the error detection data.

[0146] The following processes are performed by the transmitting communication device. For example, if the transmitting communication device is a base station 20, the following processes are performed by the generation unit 234 of the base station 20. Also, if the transmitting communication device is a terminal device 40, the following processes are performed by the generation unit 434 of the terminal device 40.

[0147] (Determination method based on the length of the coded sequence) The transmitting communication device can determine the length of the error detection data to be attached to one or more coded sequences based on the length of the one or more coded sequences. In this case, the communication device may select an error detection method to use from among several error detection methods with different bit widths of error detection data, based on the length of the coded sequences. In this case, the communication device may select an error detection method to use from among several error detection methods by applying the length of one or more coded sequences to a predetermined selection criterion. Here, the selection criterion is information for selecting an error detection method, and is information that shows the correspondence between the length of one or more coded sequences and an error detection method.

[0148] For example, assume that the error detection method is the generating polynomial used in CRC. The communication device selects the generating polynomial used in CRC by applying the coded sequence length to a predetermined selection criterion. For example, when the coded sequence length is 1 < k <= K1, the communication device selects a first-order generating polynomial, and when K1 < k < K2, it selects a fourth-order generating polynomial. Here, k is the codeword length, and K1 and K2 are boundary values for switching the generating polynomial. The boundary values may be regarded as information for the selection criterion.

[0149] Note that the receiving-side communication device may obtain the information on the selection criterion (for example, the boundary values) from another communication device that is the transmission partner of a plurality of coded sequences. For example, if the receiving-side communication device is the terminal device 40, the terminal device 40 (for example, the acquisition unit 433 of the terminal device 40) may obtain the information on the selection criterion from the base station 20 as static information. Of course, the information on the selection criterion may be determined as a fixed value in a standard or the like. At this time, the receiving-side communication device may estimate the value of the boundary value from the error detection rate estimated from the generating polynomial used in CRC. For example, the communication device may estimate the error detection estimate from the above-mentioned CRC detection ability and the length of the sequence, and change the length of the generating polynomial used based on that value.

[0150] (Determination method based on estimated error rate) The transmitting-side communication device can determine the length of the error detection data to be added to the coded sequence based on the error rate estimated when transmitting the coded sequence. For example, the communication device (for example, the acquisition unit 433 of the terminal device 40) may determine the length of the error detection data from the estimated value of the error rate based on the type of communication and the lower-layer processing. Examples of the estimated value of the error rate include 5QI, QoS, etc. For example, in 5G URLLC, coding is performed at the physical layer so that the BER (Bit Error Rate) is 10 -5 as follows. If the decoding of the error correction code is performed at a layer higher than the physical layer, the CRC length may be determined based on this information.

[0151] (Other determination methods) The length of the error detection data attached to the coded sequence may be determined by a combination of the two determination methods described above (a method based on the length of the coded sequence and a method based on the estimated error rate).

[0152] It is desirable that the generator polynomials used for error detection be a set of pre-defined generator polynomials. In this case, it is desirable that the pre-defined generator polynomials be selected to accommodate all anticipated coding sequence lengths and communication types. For example, the pre-defined generator polynomials may be CRC-24, CRC-8, and CRC-1. The communication device may dynamically set these generator polynomials during communication. The communication device may also set these generator polynomials statically or quasi-statically. The generator polynomials used for error detection may be fixedly determined by standards or other specifications.

[0153] Furthermore, the communication device may, in some cases, choose not to add error detection data to one or more coded sequences. For example, the communication device (e.g., the assignment unit 235 of the base station 20, or the assignment unit 435 of the terminal device 40) may choose not to include error detection data in redundant data if the length of one or more coded sequences and the estimated error rate when transmitting one or more coded sequences meet a predetermined standard.

[0154] <3-2-3. Error detection processing on the receiving end> Next, we will explain the error detection process in the receiving communication device.

[0155] If the receiving communication device is a base station 20, the following processing will be performed, for example, by the receiving unit 231 and / or detection unit 236 of the base station 20. If the receiving communication device is a terminal device 40, the following processing will be performed, for example, by the receiving unit 431 and / or detection unit 436 of the terminal device 40.

[0156] For the receiving communication device to perform error detection, it needs to know the error detection method (e.g., the generating polynomial) used by the transmitting communication device when generating the error detection data. Below, we will show how the receiving device can determine the generating polynomial by considering different scenarios.

[0157] First, we will explain the process when the error detection method (e.g., a generator polynomial) used by the transmitting communication device is notified to the receiving device. This error detection method information may be transmitted as quasi-static or dynamic information. If the error detection method is a generator polynomial, the transmitting communication device may notify the receiving communication device of the bit representation of the generator polynomial used to generate the error detection data. In this case, the transmitting communication device may notify the bit representation of the generator polynomial by adding it to redundant data of a specific encoding sequence. Of course, the error detection method may be notified by other methods.

[0158] Next, we will describe the process when the receiving device is notified of a list of error detection methods used by the transmitting communication device (e.g., a list of generator polynomials). In this case, we assume that the receiving communication device knows all the candidate error detection methods (e.g., generator polynomials) used by the transmitting device, but does not know which error detection method was actually used to generate the error detection data. The list of error detection methods in this case may be transmitted as quasi-static information or as dynamic information. If the error detection method is a generator polynomial, the transmitting communication device may notify the receiving communication device of the bit representation of the generator polynomial used to generate the error detection data. In this case, the transmitting communication device may notify the bit representation of the generator polynomial by adding it to the redundant data of a specific encoding sequence. Of course, the error detection method may be notified by other methods.

[0159] In this case, it is desirable for the receiving communication device to perform error detection blindly using a list of error detection methods. For example, suppose the error detection method is a generator polynomial. Then, the receiving communication device should use f as the list of generator polynomials. k (x), f l (x), f nSuppose (x)(k,l,n∈N) is obtained. In this case, the receiving communication device randomly selects one generator polynomial from the list of multiple generator polynomials and attempts to detect an error. Then, the communication device compares it with the end of the received coded sequence. If an error is detected, it selects another generator polynomial from the list and attempts to detect an error again. If there is at least one generator polynomial for which no error is detected, the communication device determines that the coded sequence is error-free. Conversely, if an error is detected even after trying all the generator polynomials in the list, the communication device determines that the sequence contains an error.

[0160] <3-3. Examples of Packetization> Next, an example of packetization of one or more coded sequences will be described.

[0161] The following processes are performed by the transmitting communication device. For example, if the transmitting communication device is a base station 20, the following processes are performed by the transmitting unit 232 and / or the assigning unit 235 of the base station 20. Also, if the transmitting communication device is a terminal device 40, the following processes are performed by the transmitting unit 432 and / or the assigning unit 435 of the terminal device 40.

[0162] The transmitting communication device stores one or more coded sequences, each with redundant data, in a data unit and transmits them. In this case, for the receiving communication device to correctly reconstruct one or more coded sequences from the packet, it is considered essential that the transmitting communication device pre-adds information (hereinafter referred to as "reconstruction information") necessary to reconstruct one or more coded sequences from the packet. The addition of reconstruction information will be explained below.

[0163] <3-3-1. Packetization> Before explaining the recovery information, let's explain packetization.

[0164] The encoded sequence with redundant data (hereinafter simply referred to as the encoded sequence in this section) is typically moved within the communication device for the communication device to perform transmission processing 2 in Figure 7. This movement may be defined as a movement to a layer lower than the layer where the disappearance correction process is located, or as a movement within the same layer. During this movement, the resource size may be notified from the transmission processing 2 side. For example, the 3GPP RLC layer has a function in the transmission process to segment (divide) the RLC SDU based on the resource size notification from the lower MAC layer and adjust the size of the SDU to match the notified size.

[0165] The process described above must also be performed in the communication scenario of this embodiment. Hereafter, the process of combining and splitting one or more coded sequences to generate an information sequence of a different size will be referred to as packetization.

[0166] <3-3-2. Packet Structure> Figure 13 shows the structure of a packet. When a communication device generates a packet from one or more coded sequences based on the resource size communicated from the next transmission process, the packet structure can be classified into configurations A to F as shown in Figure 13.

[0167] (Configuration A) Configuration A assumes that the packet size and the encoded packet size are the same. In this case, one encoded sequence is always inserted into the packet.

[0168] (Configuration B) Configuration B assumes that the packet size is larger than the encoded sequence size, and the encoded sequence size is an integer multiple of the packet size. In this case, a natural number greater than or equal to 2 is preferable. In this scenario, the packet consists only of multiple complete encoded sequences.

[0169] (Configuration C) Configuration C assumes that the size of the encoded sequence is not an integer multiple of the packet size, but rather that a portion of one encoded sequence is inserted into the remainder when the packet size is divided by the size of the encoded sequence. In other words, if the packet size is M and the size of the encoded sequence is N, it assumes that floor(M / N) encoded sequences are inserted into the packet, and then an encoded sequence divided into M / N-floor(M / N)[bit] size is inserted at the end. Here, floor(*) means the operation of rounding down the decimal part of the value of *.

[0170] (Configuration D) Configuration D assumes a case where a complete coded sequence is inserted into two parts of a single coded sequence. Here, if the size of one of the parts of the coded sequence is L, it is desirable that the size of the other part of the coded sequence is (M+L) / N - floor((M+L) / N) [bits]. It is desirable that the two divided coded sequences be placed at opposite ends of the packet.

[0171] (Configuration E) Configuration E assumes that a packet consists of a complete coded sequence, a portion of one coded sequence, and a zero-bit sequence. In this case, if the size of the zero-bit sequence is L, then it is desirable that the size of the zero-bit sequence be (M+L) / N - floor((M+L) / N)[bits].

[0172] (Configuration F) Configuration F assumes that the size of the encoded sequence is not an integer multiple of the packet size, but rather that a portion of the 0-bit sequence is inserted into the remainder of the value obtained by dividing the packet size by the size of the encoded sequence. In other words, if the packet size is M and the size of the encoded sequence is N, then it assumes that floor(M / N) encoded sequences are inserted into the packet, and a 0-bit sequence of size M / N-floor(M / N)[bits] is inserted at the end of each.

[0173] <3-3-3. Restoration Information> The receiving communication device needs to perform an operation to reconstruct the encoded sequence from the packet with the above configuration. To perform this operation, the receiving communication device needs to know what configuration the packet has. Therefore, the transmitting communication device adds information (reconstruction information) about the storage of one or more encoded sequences in the packet to the packet. The communication device may store the reconstruction information in redundant data.

[0174] The transmitting communication device may also notify the restoration information using dynamic control information notification regarding the loss correction code (for example, steps S104 and S111 in Figure 11). Alternatively, the transmitting communication device may notify the restoration information by adding redundancy to encoded packets or packets composed of zero-bit sequences. Furthermore, the transmitting communication device may notify the restoration information by methods other than those described above.

[0175] The recovery information may include the following information (1) to (6). The size of the received packet is assumed to be known at the receiving end. Furthermore, the information notified to the receiving end's communication device may consist of only a portion of the information below.

[0176] (1) Information on the size of the coded sequence stored in the packet The recovery information may include information about the size of the coded sequence contained in the packet. The communication device may also indicate the size by creating a table of coded sequence sizes in advance and associating the values ​​with numbers.

[0177] (2) Packet configuration information The restoration information may include information indicating how one or more coded sequences are stored in the packet. For example, the restoration information may include information for distinguishing configurations A through F in Figure 13.

[0178] (3) Sequence number The reconstruction information may include information (sequence numbers) to establish relationships between packets. Consider a scenario where the transmitted packets consist of some or all of configurations C, D, and E in Figure 13, and each packet contains a portion of a single coded sequence. In this case, the transmitting communication device may assign sequence numbers between packets in order for the receiving communication device to reconstruct a single coded sequence from multiple packets. For example, when a single coded sequence is divided into two packets, the transmitting communication device assigns consecutive sequence numbers to those packets. The receiving communication device attempts to reconstruct the divided coded sequence from the packet sequence numbers and information regarding the status of the divided coded sequences.

[0179] (4) Offset number of division bits When a transmitted packet consists of part or all of configurations C, D, and E in Figure 13, the transmitting communication device indicates, by bit position, which part of the original encoded sequence the beginning or end of the divided encoded sequence is located in. Both beginning and end information may be included.

[0180] (5) Status of the partitioned coding sequence When a transmitted packet consists of part or all of configurations C, D, and E in Figure 13, the transmitting communication device stores information indicating the state of the divided coded sequence in the reconstructed information. This information is used, for example, to distinguish whether the divided sequence is the beginning of the original coded sequence, the middle (not the beginning and not the end) of the original coded sequence, or the end of the original coded sequence.

[0181] (6) Operations on margins The restoration information may include information on how to handle any remaining space when one or more coded sequences are stored in the packet. For example, the restoration information may include information for distinguishing between configurations C, D, E, and F in Figure 13.

[0182] <3-3-4. Header Structure Example and Restoration Process> The transmitting communication device adds restoration information to the packet header. The transmitting communication device may also include the restoration information in redundant data attached to one or more encoded sequences. The method for adding restoration information is described below.

[0183] In a given communication, if a packet consists only of component A, the receiving end can decode it using only the information attached to the encoded sequence; therefore, it is desirable that no decomposition information is attached.

[0184] If a packet in a communication consists only of component B, the receiving end can reconstruct the encoded sequence if it can determine the size of the encoded sequence. Therefore, it is desirable that the reconstructed information includes at least information about the size of the encoded sequence.

[0185] If a packet in a communication consists only of component F, the receiving end can reconstruct the encoded sequence using, for example, the following method. Therefore, it is desirable that the reconstructed information includes at least information about the size of the encoded sequence. (1) Obtain the size of the coded sequence. (2) Divide the packets into groups of bits according to the size of the encoded sequence, starting from the beginning of the packet. (3) Discard any terminal bits that are less than the size of the encoded sequence.

[0186] If a packet in a communication consists of components B, C, D, and E, the encoding sequence can be reconstructed as follows:

[0187] (1) Identify the configuration of the received packet based on the information it contains. (For example, 00: Configuration B, 01: Configuration C, 10: Configuration D, 11: Configuration E)

[0188] (2) In configuration B, the bits are divided according to the size of the encoded sequence from the beginning of the packet.

[0189] (3) In the case of configuration C, (a) Divide the packets into groups of bits according to the size of the encoded sequence, starting from the beginning of the packet. (b) Store in a buffer the terminal bits less than the size of the encoded sequence, the status and sequence number of the segmented encoded sequence that was attached to the packet, and the offset number of the segmented bits.

[0190] (4) In the case of configuration D, (a) Extract a segmented coded sequence based on the offset number of the segmentation bits, and store the sequence, the status of the segmented coded sequence attached to the packet, the sequence number of the segmentation bits, and the offset number of the segmentation bits in a buffer. (b) For the packet after processing in (a), the bits are divided from the beginning according to the encoded sequence size. (c) Store in a buffer the terminal bits less than the size of the encoded sequence, the status and sequence number of the segmented encoded sequence that was attached to the packet, and the offset number of the segmented bits.

[0191] (5) In the case of configuration E, (a) Extract a segmented coded sequence based on the offset number of the segmentation bits, and store the sequence, the status of the segmented coded sequence attached to the packet, the sequence number of the segmentation bits, and the offset number of the segmentation bits in a buffer. (b) For the packet after processing in (a), the bits are divided from the beginning according to the encoded sequence size. (c) Discard any terminal bits that are less than the size of the encoded sequence.

[0192] (6) Based on the information, the divided information sequence stored in the buffer is restored. For this reason, if the packet in the communication consists of components C, D, and E, it is desirable that the restored information includes at least the size of the encoded sequence, the status and sequence number of the divided encoded sequence, and the offset number of the division bits.

[0193] <<4. Example of a communication configuration to which this embodiment can be applied>> The following describes an example configuration of a communication device to which this embodiment can be applied.

[0194] <4-1. Configuration Example 1> First, we will explain an example configuration where loss correction codes are used as an alternative to packet duplication in a DC (Dual Connectivity) / CA (Carrier Aggregation) environment.

[0195] In 5G standards, DA / CA improves communication reliability and expands communication capacity by using multiple communication channels (carriers) for communication with a single terminal. In particular, one method for improving reliability in DC / CA is the multiplexing of identical data by PDCP Duplication. This method involves duplicating PDCP PDUs at the PDCP layer and transmitting them on each communication channel. Figures 14 and 15 show the operation of loss correction codes when a single communication device communicates using multiple communication channels. In the examples in Figures 14 and 15, the number of communication channels used is set to 2, but it can be any natural number greater than or equal to 2. Also, the distribution method and the number of coded sequences to be generated can be any value. Furthermore, the function to add redundancy for error detection may be processed after the coded sequences are distributed according to the channels used.

[0196] The examples in Figures 14 and 15 assume that loss correction coding is applied as a reliability improvement method instead of PDCP Duplication. The transmitting side is assumed to have the following functions: the ability to perform loss correction coding on one or more PDCP SDUs, the ability to add an error detection function to each coded sequence, the ability to distribute multiple coded sequences with error detection functions according to the number and state of the communication channels used, and the ability to process the distributed sequences into PDCP PDUs for each distributed group. The receiving side is assumed to have at least the following functions: the ability to restore the PDCP PDUs received from each communication channel into coded sequences, the ability to detect errors on a coded sequence basis using the error detection function, and the ability to perform loss correction decoding using only coded sequences that do not contain errors.

[0197] When applying this embodiment under this assumption, the following additional considerations are necessary.

[0198] (1) Items relating to the redundancy length with the error detection function to be assigned In DC / CA environments, multiple PDUs generated based on distributed coded sequences may be processed by separate, independent RLC entities (for example, Dual Connectivity using multiple base stations). Therefore, when determining the size of the added redundancy based on channel state or lower-layer processing, it is desirable that the error detection function be performed after coded symbol distribution, and that the size be determined at the level of the distributed units.

[0199] (2) Items that generate PDCP PDUs from distributed series Based on the above assumptions, when generating a PDCP PDU from a correction code sequence with multiple error detection functions, the generated PDU can communicate in all states shown in Figure 13. However, considering low-latency processing, distributing the divided coding sequence across multiple communication channels is undesirable.

[0200] For example, consider a scenario where communication is performed using two communication channels, and during communication processing, the condition of one of the channels suddenly deteriorates, resulting in a temporary outage. In this case, if the divided coded sequences are distributed to each communication channel, it becomes difficult to reconstruct the divided coded sequences.

[0201] Furthermore, assuming that transmission delays differ for each communication channel, we consider arranging the divided coded sequences to be distributed to each channel. In this case, in order to reconstruct the divided coded sequences, it is necessary to wait for the divided coded sequences to arrive from both communication channels, which leads to an increase in delay.

[0202] In loss correction coding, the correction capability of each coded sequence is set to be of equal value. Therefore, in cases like the example above, it is more effective in terms of delay and complexity to, for example, adjust the size of the PDCP PDU to transmit only the coded sequences that have not been divided, or to perform zero-padding on the remaining space of the PDCP PDU packed with coded sequences.

[0203] <4-2. Configuration Example 2> Next, we will describe an example configuration using an erasure correction code as an alternative to RLC ARQ.

[0204] The RLC layer includes a function to retransmit data that failed to be received / decoded in the Segmented RLC SDU unit (RLC ARQ) and a function to divide the RLC SDU based on the size notified by the MAC layer. The processing when these functions are replaced with loss correction codes, and further when the present invention is applied, will be described.

[0205] The configuration envisioned here would have, at a minimum, the following functions on the transmitting side: the ability to perform loss-of-loss correction coding on one or more RLC SDUs; the ability to add error detection functionality to the coded sequence; the ability to generate RLC PDUs from one or more or some coded sequences based on notifications from the MAC layer; and the ability to generate additional RLC PDUs from the coded sequence based on ACK / NACK from the receiving side. On the receiving side, at a minimum, the ability to restore the coded sequence from the RLC PDUs; the ability to detect errors in the coded sequence; the ability to perform loss-of-loss correction decoding using error-free coded sequences; and the ability to notify the transmitting side of ACK / NACK based on the decoding result or the number of error-free coded sequences received.

[0206] This embodiment is also effective in the above configuration.

[0207] In RLC ARQ, retransmission is performed in Segmented RLC SDU units based on the receiver's NACK. However, when applying loss correction coding, it is preferable to send an additional loss correction coded sequence rather than the same data. This is because the correction capabilities of the coded sequences are equal. Also, when retransmission is performed, the length of the coded sequence is known at the receiver, so it is not necessary to notify the size of the coded sequence in the information added when generating a packet from multiple coded sequences.

[0208] Furthermore, the redundancy for error detection in the coded sequence included in the PDU generated during retransmission does not necessarily have to be the same length as during the initial transmission; it may be variable depending on the channel, lower-layer processing, and PDU size.

[0209] <<5. Variation>> The above-described embodiment is merely an example, and various modifications and applications are possible.

[0210] For example, in the above embodiment, the transmitting communication device was a base station 20 or a terminal device 40, and the receiving communication device was a terminal device 40 or a base station 20. However, the transmitting communication device and the receiving communication device are not limited to this example. For example, the transmitting communication device may be a terminal device 40, and the receiving communication device may be a terminal device 40. Alternatively, the transmitting communication device may be a base station 20, and the receiving communication device may be a base station 20. Furthermore, a relay station 30 may be included in either or both of the transmitting and receiving communication devices.

[0211] The control device that controls the management device 10, base station 20, relay station 30, and terminal device 40 in this embodiment may be implemented by a dedicated computer system or by a general-purpose computer system.

[0212] For example, a communication program for performing the above-described operations is stored in a computer-readable recording medium such as an optical disc, semiconductor memory, magnetic tape, or flexible disk and distributed. Then, for example, the control device is configured by installing the program on a computer and executing the above-described process. In this case, the control device may be an external device (e.g., a personal computer) of the management device 10, base station 20, relay station 30, or terminal device 40. Alternatively, the control device may be an internal device (e.g., control unit 13, control unit 23, control unit 33, or control unit 43) of the management device 10, base station 20, relay station 30, or terminal device 40.

[0213] Alternatively, the above communication program may be stored on a disk device provided by a server on a network such as the Internet, and made available for download to a computer. Furthermore, the above functions may be realized through the cooperation of an OS (Operating System) and application software. In this case, the parts other than the OS may be stored on a medium and distributed, or the parts other than the OS may be stored on a server device and made available for download to a computer.

[0214] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by known methods. In addition, the processing procedures, specific names, and information including various data and parameters shown in the above document and drawings can be arbitrarily changed unless otherwise specified. For example, the various information shown in each figure is not limited to the information shown.

[0215] Furthermore, the components of each illustrated device are functionally conceptual and do not necessarily need to be physically configured as shown. In other words, the specific forms of distribution and integration of each device are not limited to those shown, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions. This distribution and integration configuration may also be performed dynamically.

[0216] Furthermore, the above-described embodiments can be combined as appropriate in areas where the processing content is not contradictory. Also, the order of each step shown in the flowchart of the above-described embodiments can be changed as appropriate.

[0217] Furthermore, for example, this embodiment can also be implemented as any configuration that makes up a device or system, such as a processor as a system LSI (Large Scale Integration), a module using multiple processors, a unit using multiple modules, or a set with additional functions added to a unit (i.e., a configuration of a part of a device).

[0218] In this embodiment, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. Therefore, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules within a single enclosure, are both considered systems.

[0219] Furthermore, for example, this embodiment can adopt a cloud computing configuration in which a single function is shared and processed collaboratively by multiple devices via a network.

[0220] <<6. Conclusion>> As described above, the communication device of this embodiment (for example, the base station 20 and the terminal device 40) generates error detection data (for example, the CRC value) for error detection in one or more coded sequences generated by the loss correction coding process, and adds redundant data including the error detection data to one or more coded sequences. At this time, the communication device generates error detection data of different lengths according to predetermined conditions. For example, the communication device generates error detection data of a length determined based on the length of one or more coded sequences. Alternatively, the communication device generates error detection data of a length determined based on the error rate estimated when one or more coded sequences are transmitted. As a result, the communication device of this embodiment can add redundant data of an appropriate length to the coded sequences, thereby achieving high frequency utilization efficiency.

[0221] Although the embodiments of this disclosure have been described above, the technical scope of this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure. Furthermore, components from different embodiments and modifications may be combined as appropriate.

[0222] Furthermore, the effects described in each embodiment of this specification are merely illustrative and not limiting, and other effects may also occur.

[0223] Furthermore, this technology can also be configured as follows. (1) A generation unit that generates error detection data, The system includes an assignment unit that assigns redundant data, including the error detection data, to one or more coded sequences generated by coding processing, The error detection data is used for error detection of the one or more coded sequences. The generation unit generates error detection data of different lengths according to predetermined conditions. Communication device. (2) The generation unit generates error detection data of a length determined based on the length of the one or more coded sequences. The communication device described in (1) above. (3) The generation unit selects an error detection method to be used from among a plurality of error detection methods with different bit widths for the error detection data, based on the length of the one or more coding sequences, and generates the error detection data based on the selected error detection method. The communication device described in (2) above. (4) The system includes an acquisition unit that acquires information on selection criteria for selecting the error detection method, which includes information showing the correspondence between the length of the one or more coded sequences and the error detection method. The generation unit selects an error detection method to be used from among the multiple error detection methods based on the information and the length of the one or more coded sequences, and generates the error detection data based on the selected error detection method. The communication device described in (3) above. (5) The acquisition unit acquires the information from other communication devices that are the recipients of the one or more coded sequences. The communication device described in (4) above. (6) The acquisition unit determines the selection criteria based on the error detection capability of the error detection method. The communication device described in (4) above. (7) The generation unit generates error detection data of a length determined based on the estimated error rate. The communication device described in (1) above. (8) The assignment unit shall not include the error detection data in the redundant data if the length of the one or more coded sequences and the estimated error rate meet a predetermined criterion. A communication device as described in any of (1) to (7) above. (9) The aforementioned error detection data is the CRC (Cyclic Redundancy Checking) value. A communication device as described in any of (1) to (8) above. (10) A transmitting unit that stores the one or more coded sequences together with the redundant data in a packet and transmits it, The assignment unit stores in the redundant data information regarding the storage of the one or more coded sequences into the packet. A communication device as described in any of (1) to (9) above. (11) The assignment unit stores in the redundant data restoration information for restoring the one or more coded sequences from the packet. The communication device described in (10) above. (12) The restoration information includes information about the size of the encoded sequence stored in the packet. The communication device described in (11) above. (13) The restoration information includes at least configuration information of the packet showing how the one or more coded sequences are stored in the packet. The communication device described in (11) above. (14) The restoration information includes information on how to handle any remaining space when one or more encoded sequences are stored in the packet. The communication device described in (13) above. (15) When the assignment unit stores a portion of the encoded sequence in the margin, it stores in the restoration information the sequence number of the encoded sequence partially stored in the margin, and information for identifying which part of the encoded sequence the portion stored in the margin is. The communication device described in (14) above. (16) A communication device that communicates with another communication device, comprising: a generation unit that generates error detection data for error detection of one or more coded sequences generated by coding processing, the generation unit generating error detection data of different lengths according to predetermined conditions; and an assignment unit that assigns redundant data including at least the error detection data to the one or more coded sequences, A receiving unit that receives the one or more coded sequences to which the redundant data has been added from the other communication device, The system includes an error detection unit that performs error detection on one or more coding sequences based on the error detection data included in the redundant data. Communication device. (17) The other communication device is configured to generate error detection data to be included in the redundant data based on an error detection method selected from among multiple error detection methods with different bit widths for the error detection data. The receiving unit obtains information from the other communication device regarding the error detection method used to generate the error detection data. The error detection unit performs error detection on the one or more coded sequences based on information regarding the error detection method and the error detection data. The communication device described in (16) above. (18) The information relating to the error detection method is a list of the plurality of error detection methods, The error detection unit performs error detection on the one or more coded sequences by sequentially executing the error detection methods included in the list information. The communication device described in (17) above. (19) Generation step for generating error detection data, The step includes adding redundant data, which includes at least the error detection data, to one or more coded sequences generated by the coding process, The error detection data is used for error detection of the one or more coded sequences. In the generation step, error detection data of different lengths are generated according to predetermined conditions. Communication method. (20) A communication method performed by a communication device communicating with another communication device, comprising: a generation unit that generates error detection data for error detection of one or more coded sequences generated by coding processing, the generation unit generating error detection data of different lengths according to predetermined conditions; and an assignment unit that assigns redundant data including at least the error detection data to the one or more coded sequences; A receiving step of receiving the one or more coded sequences to which the redundant data has been added from the other communication device, The error detection step includes performing error detection on one or more coding sequences based on the error detection data included in the redundant data, Communication method. [Explanation of symbols]

[0224] 1. Communication System 10 Management device 20 base station 30 relay stations 40 Terminal devices 11 Communications Department 21, 31, 41 Wireless Communication Section 12, 22, 32, 42 storage section 13, 23, 33, 43 Control Unit 211, 311, 411 Transmission Processing Unit 212, 312, 412 Receiving Processing Unit 213, 313, 413 antennas 231, 431 Receiving section 232, 432 Transmitter 233, 433 Acquisition Department 234, 434 generation part 235, 435 Assigned section 236, 436 detection unit

Claims

1. A generation unit that generates error detection data, An assignment unit that assigns redundant data, including the error detection data, to one or more coded sequences generated by coding processing, A transmitting unit that stores the one or more coded sequences together with the redundant data in a packet and transmits it, The error detection data is used for error detection of the one or more coded sequences. The generation unit generates error detection data of different lengths according to predetermined conditions, The assignment unit stores in the redundant data restoration information for restoring the one or more coded sequences from the packet, the restoration information which includes at least configuration information of the packet indicating how the one or more coded sequences are stored in the packet. The restoration information includes information on how to handle any remaining space when one or more encoded sequences are stored in the packet. Communication device.

2. When the assignment unit stores a portion of the encoded sequence in the margin, it stores in the restoration information the sequence number of the encoded sequence partially stored in the margin, and information for identifying which part of the encoded sequence the portion stored in the margin is. The communication device according to claim 1.

3. The generation unit generates error detection data of a length determined based on the length of the one or more coded sequences. The communication device according to claim 1 or 2.

4. The generation unit selects an error detection method to be used from among a plurality of error detection methods with different bit widths for the error detection data, based on the length of the one or more coding sequences, and generates the error detection data based on the selected error detection method. The communication device according to claim 3.

5. The system includes an acquisition unit that acquires information on selection criteria for selecting the error detection method, which indicates the correspondence between the length of one or more coded sequences and the error detection method. The generation unit selects an error detection method to be used from among the multiple error detection methods based on the information and the length of the one or more coded sequences, and generates the error detection data based on the selected error detection method. The communication device according to claim 4.

6. The acquisition unit acquires the information from other communication devices that are the recipients of the one or more coded sequences. The communication device according to claim 5.

7. The acquisition unit determines the selection criteria based on the error detection capability of the error detection method. The communication device according to claim 6.

8. The generation unit generates error detection data of a length determined based on the estimated error rate. The communication device according to claim 1 or 2.

9. The assignment unit shall not include the error detection data in the redundant data if the length of the one or more coded sequences and the estimated error rate meet a predetermined standard. A communication device according to any one of claims 1 to 8.

10. The error detection data mentioned above is the CRC (Cyclic Redundancy Checking) value. A communication device according to any one of claims 1 to 9.

11. The restoration information includes information about the size of the encoded sequence stored in the packet. A communication device according to any one of claims 1 to 10.

12. A communication device that communicates with another communication device, comprising: a generation unit that generates error detection data for detecting errors in one or more coded sequences generated by coding processing, the generation unit generating error detection data of different lengths according to predetermined conditions; an addition unit that adds redundant data including the error detection data to the one or more coded sequences; and a transmission unit that stores the one or more coded sequences together with the redundant data in a packet and transmits it; A receiving unit that receives the packet containing the one or more coded sequences to which the redundant data has been added from the other communication device, The system includes an error detection unit that performs error detection on one or more coded sequences based on the error detection data included in the redundant data, The redundant data includes restoration information for restoring the one or more coded sequences from the packet, the restoration information which includes at least configuration information of the packet indicating how the one or more coded sequences are stored in the packet. The restoration information includes information on how to handle any remaining space when one or more encoded sequences are stored in the packet. Based on the restoration information, the one or more coded sequences are restored from the packet. Communication device.

13. The restoration information includes, as information regarding the handling of the blank space when a portion of the encoded sequence is stored in the blank space, the sequence number of the encoded sequence in which a portion is stored in the blank space, and information for identifying which part of the encoded sequence the portion stored in the blank space is. The communication device according to claim 12.

14. The other communication device is configured to generate error detection data to be included in the redundant data based on an error detection method selected from among multiple error detection methods with different bit widths for the error detection data. The receiving unit obtains information from the other communication device regarding the error detection method used to generate the error detection data. The error detection unit performs error detection on the one or more coded sequences based on information regarding the error detection method and the error detection data. The communication device according to claim 12 or 13.

15. The information relating to the error detection method is a list of the plurality of error detection methods, The error detection unit performs error detection on one or more coded sequences by sequentially executing the error detection methods included in the list information. The communication device according to claim 14.

16. A generation step for generating error detection data, A granting step of adding redundant data, including the error detection data, to one or more coded sequences generated by the coding process, A transmission step includes storing the one or more coded sequences together with the redundant data in a packet and transmitting it, The error detection data is used for error detection of the one or more coded sequences. In the generation step, error detection data of different lengths are generated according to predetermined conditions. In the granting step, the redundant data is stored with restoration information for restoring the one or more coded sequences from the packet, the restoration information which includes at least configuration information of the packet indicating how the one or more coded sequences are stored in the packet. The restoration information includes information on how to handle any remaining space when one or more encoded sequences are stored in the packet. Communication method.

17. In the assignment step, if a portion of the encoded sequence is stored in the margin, the restoration information includes the sequence number of the encoded sequence in which a portion is stored in the margin, and information for identifying which part of the encoded sequence the portion stored in the margin is. The communication method according to claim 16.

18. A communication method performed by a communication device communicating with another communication device, comprising: a generation unit that generates error detection data for detecting errors in one or more coded sequences generated by coding processing, the generation unit generating error detection data of different lengths according to predetermined conditions; an addition unit that adds redundant data including the error detection data to the one or more coded sequences; and a transmission unit that stores the one or more coded sequences together with the redundant data in a packet and transmits it; A receiving step of receiving the packet containing the one or more coded sequences to which the redundant data has been added from the other communication device, The error detection step includes performing error detection on one or more coded sequences based on the error detection data included in the redundant data, The redundant data includes restoration information for restoring the one or more coded sequences from the packet, which includes at least configuration information of the packet indicating how the one or more coded sequences are stored in the packet. The restoration information includes information on how to handle any remaining space when one or more encoded sequences are stored in the packet. Based on the restoration information, the one or more coded sequences are restored from the packet. Communication method.

19. The restoration information includes, as information regarding the handling of the blank space when a portion of the encoded sequence is stored in the blank space, the sequence number of the encoded sequence in which a portion is stored in the blank space, and information for identifying which part of the encoded sequence the portion stored in the blank space is. The communication method according to claim 18.

Images