Apparatus and method for performing quantum secure direct communications by using time bin and polarization in communication system

Abstract

The objective of the present disclosure is to perform quantum secure direct communication by using a time bin and polarization in a communication system. The method may comprise the steps of: acquiring system information; performing a random access procedure on the basis of the system information; generating a first signal; transmitting the first signal to a second device; receiving, from the second device, a second signal on which encoding has been performed using the first signal; and decoding the second signal.

Description

Device and method for performing quantum secure direct communication using time bins and polarization in a communication system

[0001] The present disclosure relates to a communication system, and more specifically to an apparatus and method for performing quantum secure direct communication (QSDC) using a time bin and polarization in a communication system.

[0002] Wireless access systems are being widely deployed to provide various types of communication services, such as voice and data. Generally, a wireless access system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access) systems.

[0003] In particular, as many communication devices require large communication capacities, enhanced mobile broadband (eMBB) communication technology is being proposed as an improvement over existing radio access technology (RAT). Furthermore, communication systems are being proposed that consider not only massive machine type communications (mmTC), which connects multiple devices and objects to provide various services anytime and anywhere, but also services and user equipment (UE) that are sensitive to reliability and latency. Various technical configurations are being proposed for this purpose.

[0004] The present disclosure relates to an apparatus and method for performing quantum secure direct communication using time bins and polarization in a communication system.

[0005] The present disclosure relates to an apparatus and method for generating higher-dimensional quantum states in a communication system.

[0006] The present disclosure relates to an apparatus and method for generating mutually unbiased initial quantum states using time and polarization properties in a communication system.

[0007] The present disclosure relates to an apparatus and method for generating higher-dimensional quantum states in a communication system using a single photon.

[0008] The present disclosure relates to an apparatus and method for generating higher-dimensional quantum states using a time bin containing a single photon and polarization applied to the single photon in a communication system.

[0009] The present disclosure relates to an apparatus and method for measuring higher-dimensional quantum states in a communication system.

[0010] The present disclosure relates to an apparatus and method for measuring the quantum bit error rate (QBER) in a communication system.

[0011] The present disclosure relates to an apparatus and method for determining whether quantum secure direct communication is interrupted based on QBER in a communication system.

[0012] The present disclosure relates to an apparatus and method for generating a quantum state using fewer time bins in a communication system.

[0013] The present disclosure relates to an apparatus and method for reducing the time to generate a high-dimensional quantum state in a communication system.

[0014] The present disclosure relates to an apparatus and method for generating quantum states having a high transmission rate in a communication system.

[0015] The technical objectives to be achieved in this disclosure are not limited to those mentioned above, and other unmentioned technical problems may be considered by those skilled in the art to which the technical configuration of this disclosure applies, based on the embodiments of this disclosure described below.

[0016] As an example of the present disclosure, a method comprises the steps of acquiring system information, performing a random access procedure based on the system information, generating a first signal, transmitting the first signal to a second device, receiving a second signal encoded using the first signal from the second device, and decoding the second signal, wherein the first signal comprises an initial quantum state generated based on a first basis or a second basis, and the initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

[0017] As an example of the present disclosure, a method comprises the steps of transmitting system information, performing a random access procedure based on the system information, receiving a first signal from a first device, generating a second signal by performing encoding using the first signal, and transmitting the second signal to the first device, wherein the first signal comprises an initial quantum state generated based on a first basis or a second basis, and the initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

[0018] As an example of the present disclosure, a first device comprises a transceiver and a processor coupled to the transceiver, wherein the processor is configured to acquire system information, perform a random access procedure based on the system information, generate a first signal, transmit the first signal to a second device, receive a second signal encoded using the first signal from the second device, and perform decoding of the second signal, wherein the first signal comprises an initial quantum state generated based on a first basis or a second basis, and the initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

[0019] As an example of the present disclosure, a second device comprises a transceiver and a processor connected to the transceiver, wherein the processor transmits system information, performs a random access procedure based on the system information, receives a first signal from a first device, generates a second signal by performing encoding using the first signal, and controls the transmission of the second signal to the first device, wherein the first signal includes an initial quantum state generated based on a first basis or a second basis, and the initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

[0020] As an example of the present disclosure, a terminal comprises at least one processor and at least one computer memory connected to the at least one processor and storing instructions that direct operations as executed by the at least one processor, wherein the operations include the steps of acquiring system information, performing a random access procedure based on the system information, generating a first signal, transmitting the first signal to a second device, receiving a second signal from the second device that is encoded using the first signal, and decoding the second signal, wherein the first signal comprises an initial quantum state generated based on a first basis or a second basis, and the initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

[0021] As an example of the present disclosure, a non-transitory computer-readable medium storing at least one instruction comprises said at least one instruction executable by a processor, said at least one instruction being configured such that the device acquires system information, performs a random access procedure based on said system information, generates a first signal, transmits said first signal to a second device, receives from the second device a second signal encoded using said first signal, and performs decoding of said second signal, wherein the first signal comprises an initial quantum state generated based on a first basis or a second basis, said initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to said at least one time bin.

[0022] The embodiments of the present disclosure described above are merely some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the present disclosure can be derived and understood by those skilled in the art based on the detailed description of the present disclosure set forth below.

[0023] The following effects may be achieved by embodiments based on the present disclosure.

[0024] According to the present disclosure, quantum secure direct communication can be efficiently performed in terms of transmission volume and transmission speed.

[0025] The effects obtainable from the embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by a person skilled in the art to which the technical configuration of the present disclosure applies from the description of the embodiments of the present disclosure below. That is, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived by a person skilled in the art from the embodiments of the present disclosure.

[0026] The drawings attached below are intended to aid in understanding the present disclosure and may provide embodiments of the present disclosure together with the detailed description. However, the technical features of the present disclosure are not limited to specific drawings, and features disclosed in each drawing may be combined with one another to form new embodiments. Reference numerals in each drawing may denote structural elements.

[0027] FIG. 1 illustrates an example of a communication system applicable to the present disclosure.

[0028] FIG. 2 illustrates an example of a wireless device applicable to the present disclosure.

[0029] FIG. 3 illustrates a method for processing a transmission signal applicable to the present disclosure.

[0030] FIG. 4 illustrates a communication procedure between a terminal and a base station applicable to the present disclosure.

[0031] FIG. 5 illustrates an example of a communication structure that can be provided in a 6G (6th generation) system applicable to the present disclosure.

[0032] FIG. 6 illustrates an electromagnetic spectrum applicable to the present disclosure.

[0033] FIG. 7 illustrates a transmitter structure applicable to the present disclosure.

[0034] FIG. 8 illustrates an example of a functional framework for the application of artificial intelligence technology applicable to the present disclosure.

[0035] FIG. 9 illustrates an example of a procedure for utilizing an artificial intelligence model applicable to the present disclosure.

[0036] FIG. 10 illustrates a communication procedure based on artificial intelligence (AI) technology applicable to the present disclosure.

[0037] FIG. 11 illustrates an example of a device that transmits or receives quantum information in a DL04 QSDC protocol according to one embodiment of the present disclosure.

[0038] FIG. 12 illustrates an example of a device that transmits or receives quantum information in a Two-step QSDC protocol according to one embodiment of the present disclosure.

[0039] FIGS. 13a and FIGS. 13b illustrate examples of devices for transmitting or receiving quantum information using time bins and phases in a QSDC technique according to one embodiment of the present disclosure.

[0040] FIG. 14 illustrates an example in which an N-dimensional basis state is generated based on time bins and phases according to one embodiment of the present disclosure.

[0041] FIGS. 15a and FIG. 15b illustrate examples of a method for configuring the time and phase states of an N-dimensional QSDC according to one embodiment of the present disclosure.

[0042] FIGS. 16a and FIGS. 16b illustrate examples of devices for performing a four-dimensional QSDC protocol using time and polarization according to one embodiment of the present disclosure.

[0043] FIG. 17 illustrates an example of an initial quantum state included in an initial quantum signal according to one embodiment of the present disclosure.

[0044] FIG. 18 illustrates examples of devices included in a QBER estimation part according to one embodiment of the present disclosure.

[0045] FIG. 19 illustrates examples of devices included in a message encoding part according to one embodiment of the present disclosure.

[0046] FIG. 20 illustrates examples of devices for performing message decoding according to one embodiment of the present disclosure.

[0047] FIG. 21 illustrates an example in which a receiving node performs a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure.

[0048] FIG. 22 illustrates an example in which a transmitting node performs a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure.

[0049] FIG. 23 illustrates an example in which a transmitting node determines the presence of an eavesdropper in a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure.

[0050] FIG. 24 illustrates an example of signaling for performing a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure.

[0051] FIG. 25 illustrates an example of a wireless device applicable to the present disclosure.

[0052] FIG. 26 illustrates an example of a portable device applicable to the present disclosure.

[0053] FIG. 27 illustrates an example of a vehicle or autonomous vehicle applicable to the present disclosure.

[0054] FIG. 28 illustrates an example of a vehicle applicable to the present disclosure.

[0055] FIG. 29 illustrates an example of an XR (extended reality) device applicable to the present disclosure.

[0056] FIG. 30 illustrates an example of a robot applicable to the present disclosure.

[0057] FIG. 31 illustrates an example of an AI device applicable to the present disclosure.

[0058] The following embodiments are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature may be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, some components and / or features may be combined to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of any embodiment may be included in other embodiments, or may be replaced with corresponding components or features of other embodiments.

[0059] In the description of the drawings, procedures or steps that could obscure the gist of the present disclosure have not been described, nor have procedures or steps that are understandable to those skilled in the art been described.

[0060] Throughout the specification, when a part is described as "comprising" or "including" a component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "...part," "...unit," and "module" as used in the specification refer to a unit that performs at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software. Additionally, "one (a or an)," "one," "the," and similar related terms may be used in the context describing the present disclosure (particularly in the context of the following claims) in both singular and plural forms, unless otherwise indicated in the specification or clearly contradicted by the context.

[0061] In this specification, the embodiments of the present disclosure are described with a focus on the data transmission and reception relationship between a base station and a mobile station. Here, the base station refers to a terminal node of a network that communicates directly with a mobile station. Specific operations described in this document as being performed by a base station may, in some cases, be performed by an upper node of the base station.

[0062] That is, in a network consisting of multiple network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this case, 'base station' may be replaced by terms such as fixed station, Node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.

[0063] Additionally, in embodiments of the present disclosure, the term terminal may be replaced with terms such as user equipment (UE), mobile station (MS), subscriber station (SS), mobile subscriber station (MSS), mobile terminal, or advanced mobile station (AMS).

[0064] Furthermore, the transmitting end refers to a fixed and / or mobile node that provides data or voice services, and the receiving end refers to a fixed and / or mobile node that receives data or voice services. Therefore, in the case of the uplink, a mobile station can be the transmitting end and a base station can be the receiving end. Similarly, in the case of the downlink, a mobile station can be the receiving end and a base station can be the transmitting end.

[0065] Embodiments of the present disclosure may be supported by standard documents disclosed in at least one of the wireless access systems, such as IEEE 802.xx systems, 3GPP (3rd Generation Partnership Project) systems, 3GPP LTE (Long Term Evolution) systems, 3GPP 5G (5th generation) NR (New Radio) systems and 3GPP2 systems, and in particular, embodiments of the present disclosure may be supported by 3GPP TS (technical specification) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321 and 3GPP TS 38.331 documents.

[0066] In addition, the embodiments of the present disclosure may be applied to other wireless access systems and are not limited to the systems described above. For example, they may be applicable to systems applied after the 3GPP 5G NR system and are not limited to specific systems.

[0067] That is, obvious steps or parts not described in the embodiments of the present disclosure may be described by referring to the aforementioned documents. Additionally, all terms disclosed in this document may be explained by the aforementioned standard documents.

[0068] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the technical configuration of the present disclosure can be implemented.

[0069] Additionally, specific terms used in the embodiments of the present disclosure are provided to aid in understanding the present disclosure, and the use of such specific terms may be modified in other forms without departing from the technical spirit of the present disclosure.

[0070] The following technology can be applied to various wireless access systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access).

[0071] For the sake of clarity, the following description is based on 3GPP communication systems (e.g., LTE, NR, etc.), but the technical scope of this disclosure is not limited thereto. LTE may refer to technology from 3GPP TS 36.xxx Release 8 onwards. Specifically, LTE technology from 3GPP TS 36.xxx Release 10 onwards is referred to as LTE-A, and LTE technology from 3GPP TS 36.xxx Release 13 onwards may be referred to as LTE-A pro. 3GPP NR may refer to technology from TS 38.xxx Release 15 onwards. 3GPP 6G may refer to technology from TS Release 17 and / or Release 18 onwards. "xxx" indicates a specific standard document number. LTE / NR / 6G may be collectively referred to as 3GPP systems.

[0072] Regarding the background technology, terms, abbreviations, etc. used in this disclosure, reference may be made to standard documents published prior to this disclosure. For example, reference may be made to standard documents 36.xxx and 38.xxx.

[0073] Communication systems applicable to the present disclosure

[0074] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods, and / or flowcharts of the disclosure disclosed in this document may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0075] Examples are provided in more detail below with reference to the drawings. In the following drawings and descriptions, the same reference numerals may represent the same or corresponding hardware blocks, software blocks, or function blocks unless otherwise described.

[0076] FIG. 1 illustrates an example of a communication system to which the present disclosure applies.

[0077] Referring to FIG. 1, the communication system (100) to which the present disclosure applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (extended reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI (artificial intelligence) device / server (100g). For example, the vehicle may include a vehicle equipped with wireless communication capabilities, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle (100b-1, 100b-2) may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device (100c) includes an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. The portable device (100d) may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch, smart glasses), a computer (e.g., a laptop, etc.). The home appliance (100e) may include a TV, a refrigerator, a washing machine, etc. The IoT device (100f) may include a sensor, a smart meter, etc.For example, the base station (120) and network (130) may also be implemented as wireless devices, and a specific wireless device (120a) may act as a base station / network node to other wireless devices.

[0078] Wireless devices (100a to 100f) can be connected to a network (130) through a base station (120). AI technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (100g) through the network (130). The network (130) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, or a 6G network. The wireless devices (100a to 100f) may communicate with each other through the base station (120) / network (130), but may also communicate directly (e.g., sidelink communication) without going through the base station (120) / network (130). For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (vehicle to vehicle) / V2X (vehicle to everything) communication). Also, an IoT device (100f) (e.g., a sensor) can communicate directly with another IoT device (e.g., a sensor) or other wireless devices (100a to 100f).

[0079] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a to 100f) / base station (120) and between base station (120) / base station (120). Here, wireless communication / connection can be established through various wireless access technologies such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and communication between base stations (150c) (e.g., relay, IAB (integrated access backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on the various proposals of the present disclosure, at least some of the following may be performed: a process for setting various configuration information for transmitting / receiving wireless signals, a process for various signal processing (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), a resource allocation process, etc.

[0080] Devices applicable to the present disclosure

[0081] FIG. 2 illustrates an example of a wireless device that can be applied to the present disclosure.

[0082] Referring to FIG. 2, the wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, LTE-A, LTE-A pro, NR, 5G, 5G-A, 6G). The wireless device (200) includes at least one processor (202) and at least one memory (204), and may additionally include at least one transceiver (206) and / or at least one antenna (208).

[0083] The processor (202) controls the memory (204) and / or the transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this document. For example, the processor (202) may process information within the memory (204) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a second information / signal through the transceiver (206) and then store information obtained from the signal processing of the second information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operations disclosed in this document. Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology. A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through at least one antenna (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with a radio frequency (RF) unit. In this disclosure, a wireless device may mean a communication modem / circuit / chip.

[0084] Hereinafter, hardware elements of the wireless device (200) will be described in more detail. Although not limited thereto, at least one protocol layer may be implemented by at least one processor (202). For example, at least one processor (202) may implement at least one layer (e.g., functional layers such as PHY (physical), MAC (media access control), RLC (radio link control), PDCP (packet data convergence protocol), RRC (radio resource control), and SDAP (service data adaptation protocol). At least one processor (202) may generate at least one PDU (Protocol Data Unit) and / or at least one SDU (service data unit) according to the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. At least one processor (202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods and / or operation sequences disclosed in this document. At least one processor (202) may generate a signal (e.g., baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to at least one transceiver (206). At least one processor (202) may receive a signal (e.g., baseband signal) from at least one transceiver (206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document.

[0085] At least one processor (202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. At least one processor (202) may be implemented by hardware, firmware, software, or a combination thereof. For example, at least one application-specific integrated circuit (ASIC), at least one digital signal processor (DSP), at least one digital signal processing device (DSPD), at least one programmable logic device (PLD), or at least one field programmable gate array (FPGA) may be included in at least one processor (202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be included in at least one processor (202) or stored in at least one memory (204) and driven by at least one processor (202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0086] At least one memory (204) may be connected to at least one processor (202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. At least one memory (204) may be composed of ROM (read-only memory), RAM (random access memory), EPROM (erasable programmable read-only memory), flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. At least one memory (204) may be located inside and / or outside of at least one processor (202). Additionally, at least one memory (204) may be connected to at least one processor (202) via various technologies, such as wired or wireless connections.

[0087] At least one transceiver (206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc. of this document to at least one other device. At least one transceiver (206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc. disclosed in this document from at least one other device. For example, at least one transceiver (206) may be connected to at least one processor (202) and may transmit and receive wireless signals. For example, at least one processor (202) may control at least one transceiver (206) to transmit user data, control information, or wireless signals to at least one other device. Additionally, at least one processor (202) may control at least one transceiver (206) to receive user data, control information, or wireless signals from at least one other device. Additionally, at least one transceiver (206) may be connected to at least one antenna (208), and at least one transceiver (206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document through at least one antenna (208). In this document, at least one antenna may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). At least one transceiver (206) may convert the received wireless signals / channels, etc., from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc., using at least one processor (202). At least one transceiver (206) may convert the processed user data, control information, wireless signals / channels, etc., from baseband signals to RF band signals using at least one processor (202).To this end, at least one transceiver (206) may include an (analog) oscillator and / or filter.

[0088] The components of the wireless device described with reference to FIG. 2 may be referred to by other terms in terms of their function. For example, the processor (202) may be referred to as the control unit, the transceiver (206) as the communication unit, and the memory (204) as the storage unit. In some cases, the communication unit may be used to mean at least a part of the processor (202) and the transceiver (206).

[0089] The structure of the wireless device described with reference to FIG. 2 can be understood as the structure of at least part of various devices. For example, the structure of the wireless device exemplified in FIG. 2 may be at least part of the various devices described with reference to FIG. 1 (e.g., robot (100a), vehicle (100b-1, 100b-2), XR device (100c), portable device (100d), home appliance (100e), IoT device (100f), AI device / server (100g)). Furthermore, according to various embodiments, the device may include other components in addition to the components exemplified in FIG. 2.

[0090] For example, the device may be a portable device such as a smartphone, smartpad, wearable device (e.g., smart watch, smart glasses), or portable computer (e.g., laptop, etc.). In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc., an interface unit that includes at least one port for connection with another device (e.g., audio input / output port, video input / output port), and an input / output unit for inputting and outputting video information / signals, audio information / signals, data, and / or information input by a user.

[0091] For example, the device may be a mobile device such as a mobile robot, vehicle, train, manned / unmanned aerial vehicle (AV), or ship. In this case, the device may further include at least one of a drive unit comprising at least one of an engine, motor, power train, wheel, brake, and steering device of the device; a power supply unit that supplies power and includes a wired / wireless charging circuit, battery, etc.; a sensor unit that senses state information, environmental information, and user information of the device or its surroundings; an autonomous driving unit that performs functions such as path maintenance, speed control, and destination setting; and a position measurement unit that acquires position information of the moving body through a GPS (global positioning system) and various sensors.

[0092] For example, the device may be an XR device such as an HMD, a HUD (head-up display) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. In this case, the device may further include at least one of a power supply unit that supplies power and includes a wired / wireless charging circuit, a battery, etc., an input / output unit that acquires control information, data, etc. from the outside and outputs a generated XR object, and a sensor unit that senses state information, environment information, and user information of the device or the surroundings of the device.

[0093] For example, the device may be a robot that can be classified into industrial, medical, household, military, etc., depending on the purpose or field of use. In this case, the device may further include at least one of a sensor unit that senses state information, environmental information, and user information of the device or its surroundings, and a drive unit that performs various physical actions, such as moving robot joints.

[0094] For example, the device may be an AI device such as a TV, projector, smartphone, PC, laptop, digital broadcasting terminal, tablet PC, wearable device, set-top box (STB), radio, washing machine, refrigerator, digital signage, robot, vehicle, etc. In this case, the device may further include at least one of an input unit that acquires various types of data from the outside, an output unit that generates output related to sight, hearing, or touch, a sensor unit that senses state information, environmental information, and user information of the device or its surroundings, and a training unit that learns a model composed of an artificial neural network using training data.

[0095] The structure of the wireless device illustrated in FIG. 2 can be understood as part of a RAN node (e.g., base station, DU, RU, RRH, etc.). That is, the device illustrated in FIG. 2 may be a RAN node. In this case, the device may further include a wired transceiver for front haul and / or back haul communication. However, if the front haul and / or back haul communication is based on wireless communication, at least one transceiver (206) illustrated in FIG. 2 is used for front haul and / or back haul communication, and the wired transceiver may not be included.

[0096] FIG. 3 illustrates a method for processing a transmission signal applicable to the present disclosure. For example, the transmission signal may be processed by a signal processing circuit. In this case, the signal processing circuit (300) may include scramblers (310), modulators (320), a layer mapper (330), a precoder (340), resource mappers (350), and signal generators (360). In this case, for example, the operation / function of FIG. 3 may be performed in the processor (202) and / or transceiver (206) of FIG. 2. Also, for example, the hardware elements of FIG. 3 may be implemented in the processor (202) and / or transceiver (206) of FIG. 2. For example, blocks 310 to 360 may be implemented in the processor (202) of FIG. 2. Additionally, blocks 310 to 350 may be implemented in the processor (202) of FIG. 2, and block 360 may be implemented in the transceiver (206) of FIG. 2, and are not limited to the embodiments described above.

[0097] A codeword can be converted into a wireless signal through the signal processing circuit (300) of FIG. 3. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transmission block (e.g., UL-SCH transmission block, DL-SCH transmission block). Here, the information block may include AI-related data (e.g., training data, AI model data, input data, output data, etc.), and the codeword may be an encoded bit sequence corresponding to the AI-related data. The wireless signal may be transmitted through various physical channels (e.g., PUSCH, PDSCH). Specifically, the codeword may be converted into a scrambled bit sequence by scramblers (310). The scrambled sequence used for scrambling is generated based on an initialization value, which may include ID information of the wireless device, etc. The scrambled bit sequence may be modulated into a modulation symbol sequence by modulators (320). Modulation methods may include pi / 2-BPSK (pi / 2-binary phase shift keying), m-PSK (m-phase shift keying), m-QAM (m-quadrature amplitude modulation), etc.

[0098] A complex modulation symbol sequence can be mapped to at least one transmission layer by a layer mapper (330). Here, a transmission layer is a logical resource unit for mapping signals or data transmitted through spatial resources to antenna ports, and one transmission layer can correspond to one stream or one antenna port. Each complex modulation symbol included in the complex modulation symbol sequence is mapped to at least one transmission layer, thereby determining which antenna port it will be transmitted through. The modulation symbols of each transmission layer can be mapped to the corresponding antenna port(s) by a precoder (340). The output z of the precoder (340) can be obtained by multiplying the output y of the layer mapper (330) by an N×M precoding matrix W, where N is the number of antenna ports and M is the number of transmission layers. Here, the precoder (340) can perform precoding after performing transform precoding (e.g., a discrete Fourier transform (DFT)) on the complex modulation symbols. Additionally, the precoder (340) can perform precoding without performing transform precoding.

[0099] Resource mappers (350) can map the modulation symbols of each antenna port to time-frequency resources. The time-frequency resources may include multiple symbols (e.g., CP-OFDMA symbols, DFT-s-OFDMA symbols) in the time domain and multiple subcarriers in the frequency domain. Signal generators (360) generate radio signals from the mapped modulation symbols, and the generated radio signals can be transmitted to other devices through each antenna. To this end, each of the signal generators (360) may include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), a frequency uplink converter, etc.

[0100] The signal processing process for a received signal in a wireless device can be configured as the inverse of the signal processing process (310 to 360) of FIG. 3. For example, a wireless device (e.g., 200 in FIG. 2) can receive a wireless signal from the outside through an antenna port / transceiver. The received wireless signal can be converted into a baseband signal through a signal restorer. To this end, the signal restorer may include a frequency downlink converter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. Subsequently, the baseband signal can be restored into a codeword through a resource de-mapper process, a postcoding process, a demodulation process, and a de-scrambling process. The codeword can be restored into the original information block through decoding. Accordingly, a signal processing circuit (not shown) for a received signal may include a signal restorer, a resource de-mapper, a postcoder, a demodulator, a de-scrambler, and a decoder.

[0101] The signal processing circuit (300) described with reference to FIG. 3 is illustrated as including a plurality of scramblers (310), modulators (320), a plurality of resource mappers (350), and a plurality of signal generators (360). However, at least one of the scramblers, modulators, resource mappers, and signal generators may be implemented as a single integrated structure. That is, the number of at least one of the scramblers, modulators, resource mappers, and signal generators may be less than the number of layers. Furthermore, at least one of the components illustrated in FIG. 3 may be omitted.

[0102] FIG. 4 illustrates a communication procedure between a terminal and a base station applicable to the present disclosure. FIG. 4 illustrates the operation of a terminal (410) and a base station (420) transmitting and / or receiving data, and the operation performed prior to this.

[0103] Referring to FIG. 4, in step 401, the terminal (410) and the base station (420) perform synchronization. For example, the terminal (410) performs an initial cell search operation. Specifically, the terminal (410) can detect at least one synchronization signal transmitted from the base station (420) according to a predefined rule. Here, the synchronization signal may include a plurality of synchronization signals (e.g., primary synchronization signal, secondary synchronization signal) classified according to structure or use. Through this, the terminal (410) can identify the boundaries of the frame, subframe, slot, and / or symbol of the base station (420) and obtain information about the base station (420) (e.g., cell identifier).

[0104] In step 403, the terminal (410) obtains system information transmitted from the base station (420). The system information is information related to the attributes, characteristics, and / or capabilities of the base station (420) required to connect to the base station (420) and use the service, and can be classified according to content (e.g., whether it is essential for connection), transmission structure (e.g., channel used, whether it is provided on-demand), etc., and can be classified, for example, into a master information block (MIB) and a system information block (SIB). If necessary, the terminal (410) may transmit a signal requesting the system information prior to receiving the system information. The system information may include information related to AI functions. For example, the system information is information required for operations performed based on AI, and may include at least one of information related to an AI model, information related to training, and information related to inference / prediction. However, the request and provision of the system information may be performed after the random access procedure described later.

[0105] In step 405, the terminal (410) and the base station (420) perform a random access procedure. The terminal (410) may transmit and / or receive at least one message for the random access procedure (e.g., random access preamble, RAR (random access response) message, etc.) based on information related to the random access channel of the base station (420) obtained through system information (e.g., channel location, channel structure, structure of supported preamble, etc.). For example, the terminal (410) may transmit a preamble (e.g., MSG1) through the random access channel, receive a RAR message (e.g., MSG2), transmit a message (e.g., MSG3) containing information related to the terminal (410) (e.g., identification information) to the base station (420) using scheduling information included in the RAR message, and receive a message (e.g., MSG4) for contention resolution and / or connection establishment. As another example, MSG1 and MSG3 can be transmitted and received as a single message, or MSG2 and MSG4 can be transmitted and received as a single message.

[0106] In step 407, the terminal (410) and the base station (420) perform signaling of control information. Here, the control information may be defined in various layers, such as a layer that controls the connection (e.g., a radio resource control (RRC) layer), a layer that handles mapping between logical channels and transmission channels (e.g., a media access control (MAC) layer), and a layer that handles physical channels (e.g., a physical (PHY) layer). For example, the terminal (410) and the base station (420) may perform at least one of signaling to establish a connection, signaling to determine settings related to communication, and signaling to indicate allocated resources. Additionally, the signaling of control information may be performed to convey information related to AI functions. For example, information related to AI functions is information necessary for operations performed based on AI, and may include at least one of information related to an AI model, information related to training, and information related to inference / prediction. More specifically, the information related to the AI ​​function signaled in step 407 can be combined and / or combined with the information related to the AI ​​function signaled in step 403, and both can be defined as having a hierarchical, mutually complementary, or substitute structure.

[0107] In step 409, the terminal (410) and the base station (420) transmit and / or receive data. That is, the terminal (410) and the base station (420) can process, transmit and / or receive data based on the signaling of control information. For example, when transmitting data, the terminal (410) or the base station (420) may perform at least one of channel encoding, rate matching, scrambling, constellation mapping, layer mapping, waveform modulation, antenna mapping, and resource mapping on the information bits. Conversely, when receiving data, the terminal (410) or the base station (420) may perform at least one of signal extraction from resources, antenna-specific waveform demodulation, signal placement considering layer mapping, constellation demapping, descrambling, and channel decoding. Here, the transmitted data is AI-related data, and may include, for example, data for AI-based operations or data generated by AI-based operations.

[0108] Steps 401 through 409 described with reference to FIG. 4 must not necessarily be performed in the order exemplified in FIG. 4, and the order of at least some of the steps may vary. Additionally, at least some of steps 401 through 409 may be combined into a single step or omitted. That is, the steps exemplified in FIG. 4 may be performed in various modified forms.

[0109] 6G communication systems and core implementation technologies of 6G systems

[0110] 5G systems define various operating bands within FR1 (frequency range 1), which includes 410 MHz to 7125 MHz, and FR2 (frequency range 2), which includes 24,250 MHz to 71,000 MHz. Various frequencies are being discussed as operating bands for subsequent 6G systems, and the use of frequencies higher than those of 5G systems is also being considered for wider bandwidth and higher transmission speeds. As one example, the use of the THz (Terahertz) frequency band, which includes approximately 100 GHz to 10 THz, is being discussed. The THz frequency band is a band that possesses both the penetrability of radio waves and the directivity of optical waves, and communication using the THz frequency band is expected to play a transitional role from existing radio-based communication to optical-based communication.

[0111] As such, 6G systems utilizing the THz frequency band aim for i) very high data rates per device, ii) a very large number of connected devices, iii) global connectivity, iv) very low latency, v) reduced energy consumption of battery-free IoT devices, vi) ultra-reliable connectivity, and vii) connected intelligence with machine learning capabilities. The vision of 6G systems can be four aspects such as "intelligent connectivity," "deep connectivity," "holographic connectivity," and "ubiquitous connectivity," and 6G systems can be designed to satisfy requirements such as those shown in [Table 1] below.

[0112] Per device peak data rate1 TbpsE2E latency1 msMaximum spectral efficiency100 bps / HzMobility supportup to 1000 km / hrSatellite integrationFullyAIFullyAutonomous vehicleFullyXRFullyHaptic CommunicationFully

[0113] At this time, the 6G system may have key factors such as enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLC), massive machine type communications (mMTC), AI integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security. FIG. 5 illustrates an example of a communication structure that can be provided by a 6G system applicable to the present disclosure. Referring to FIG. 5, the 6G system is expected to have simultaneous wireless communication connectivity 50 times higher than that of a 5G wireless communication system. URLLC, a key feature of 5G, is expected to become an even more dominant technology in 6G communication by providing end-to-end latency of less than 1ms. In this case, 6G systems will have significantly superior volumetric spectral efficiency, unlike the frequently used area-spectral efficiency. Since 6G systems can provide very long battery life and advanced battery technology for energy harvesting, mobile devices in 6G systems may not need to be charged separately. New network characteristics in 6G may be as follows.

[0114] - Satellite Integrated Network: 6G is expected to be integrated with satellites to provide a global mobile population. Integrating terrestrial, satellite, and airborne networks into a single wireless communication system is crucial for 6G.

[0115] - Connected Intelligence: Unlike previous generations of wireless communication systems, 6G is innovative and will update wireless evolution from "connected things" to "connected intelligence." AI can be applied at each stage of the communication process (or at each step of the signal processing described below).

[0116] - Seamless integration of wireless information and energy transfer: 6G wireless networks will transfer power to charge the batteries of devices such as smartphones and sensors. Therefore, wireless information and energy transfer (WIET) will be integrated.

[0117] - Ubiquitous Super 3D Connectivity: Connectivity to the network and core network functions of drones and very low Earth orbit satellites will create Super 3D connectivity in 6G ubiquitous.

[0118] Some general requirements regarding the new network characteristics of 6G mentioned above may be as follows.

[0119] - Small cell networks: The idea of ​​small cell networks was introduced to improve the quality of received signals in cellular systems as a result of increased throughput, energy efficiency, and spectrum efficiency. Consequently, small cell networks are an essential feature of communication systems for 5G and beyond 5G (5GB). Therefore, 6G communication systems also adopt the characteristics of small cell networks.

[0120] - Ultra-dense heterogeneous network: Ultra-dense heterogeneous networks will be another important characteristic of 6G communication systems. Multi-tier networks composed of heterogeneous networks improve overall QoS and reduce costs.

[0121] - High-capacity backhaul: Backhaul connections are characterized as high-capacity backhaul networks to support high-volume traffic. High-speed fiber optics and free-space optics (FSO) systems can be possible solutions to this problem.

[0122] - Radar technology integrated with mobile technology: High-precision localization (or location-based services) through communication is one of the functions of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0123] - Softwarization and virtualization: Softwarization and virtualization are two important features that form the basis of the design process in 5GB networks to ensure flexibility, reconfigurability, and programmability. Additionally, billions of devices can be shared across a shared physical infrastructure.

[0124] To satisfy the aforementioned characteristics, technologies such as artificial intelligence (AI), THz (Terahertz) communication, optical wireless technology, FSO backhaul network, massive MIMO technology, blockchain, 3D networking, quantum communication, unmanned aerial vehicles, cell-free communication, wireless information and energy transfer (WIET), integration of sensing and communication, integration of access backhaul networks, holographic beamforming, big data analysis, and large intelligent surface (LIS) may be adopted as core implementation technologies of the 6G system.

[0125] For example, THz communication can be utilized in 6G systems. THz communication is a communication that uses a spectrum in the frequency band between 0.3 THz and 3 THz with a corresponding wavelength in the range of 0.1 mm to 1 mm as shown in Fig. 6. Referring to Fig. 6, the frequency band of the THz wave is located in the intermediate region between the infrared band and the millimeter wave band; accordingly, the THz wave can be understood as a radio wave with the shortest wavelength and, at the same time, a light wave with the longest wavelength. As a result, the THz wave shares some characteristics of infrared and microwave waves, and specifically, can simultaneously possess the penetrability of electromagnetic waves and the directivity of light waves.

[0126] FIG. 7 illustrates a transmitter structure applicable to the present disclosure.

[0127] Referring to Fig. 7, in order to modulate data onto an optical signal, the optical source of a laser can be passed through an optical wave guide to change the phase of the signal. At this time, data is loaded by changing electrical characteristics through a microwave contact, etc. Therefore, the optical modulator output is formed as a modulated waveform.

[0128] Data may be provided by a data signal generator. Here, the data may include various user data, configuration information, control information, etc. transmitted through a channel. Furthermore, the data may include data related to AI-based operations, for example, information for configuring an AI model, input / output data for tasks of an AI model, etc. To this end, components related to AI functions (e.g., an AI processing unit) may be included in the data signal generator or may interact with the data signal generator.

[0129] An O / E converter can generate THz pulses based on optical rectification by a nonlinear crystal, O / E conversion by a photoconductive antenna, emission from a bundle of relativistic electrons, etc. THz pulses generated in such a manner can have a length ranging from femtoseconds to picoseconds. The O / E converter performs down-conversion by utilizing the non-linearity of the device.

[0130] When considering the usage of the THz spectrum, it is highly likely that multiple contiguous GHz bands will be used for fixed or mobile service applications for THz systems. According to outdoor scenario criteria, available bandwidth can be classified based on an oxygen attenuation of 10^2 dB / km in the spectrum up to 1 THz. Accordingly, a framework in which the available bandwidth is composed of multiple band chunks can be considered. As an example of the above framework, if the length of the THz pulse for a single carrier is set to 50 ps, ​​the bandwidth (BW) becomes approximately 20 GHz.

[0131] Effective down-conversion from the infrared band to the THz band depends on how the nonlinearity of the photoelectric converter (O / E converter) is utilized. In other words, to achieve down-conversion to the desired THz band, it is required to design an O / E converter with the most ideal nonlinearity for transferring to that specific band. If an O / E converter that does not match the target frequency band is used, there is a high probability of errors occurring regarding the amplitude and phase of the corresponding pulse.

[0132] In a single-carrier system, a THz transceiver system can be implemented using a single photoelectric converter. Depending on the channel environment, in a multi-carrier system, as many photoelectric converters as there are carriers may be required. This phenomenon will be particularly pronounced in multi-carrier systems utilizing multiple broadbands according to the plans related to the aforementioned spectrum applications. In this regard, a frame structure for the multi-carrier system may be considered. A signal down-frequency converted based on a photoelectric converter can be transmitted in a specific resource region (e.g., a specific frame). The frequency domain of the specific resource region may include multiple chunks. Each chunk may consist of at least one component carrier (CC).

[0133] AI technology can be introduced in 6G systems. Efficient resource management and optimization are required to maintain connectivity between various services and devices. AI technology may include techniques capable of performing data analysis, pattern recognition, and predictive modeling using AI / ML (artificial intelligence / machine learning) models. Here, an AI / ML model can be understood as a set of parameter values ​​and / or weight values ​​related to mathematical formulas or algorithms generated through learning, designed to discover patterns in input data or perform predictions. To create such an AI / ML model, an AI / ML model training procedure is required to build the model by learning the relationship between input and output in a data-driven manner. Various learning algorithms, such as supervised learning, unsupervised learning, and reinforcement learning, can be utilized as training algorithms. Users can input specific data into a trained AI / ML model to generate output, and the procedure of obtaining output data by inputting input data into the AI / ML model can be referred to as AI / ML 'inference' or 'prediction'.

[0134] Network control parameters can be obtained as output through AI / ML inference using trained AI / ML models. Users can improve network efficiency by utilizing these output parameter values. For example, AI technology can be applied in various fields, such as wireless network resource allocation, traffic management, fault prediction, and Quality of Service (QoS) management. In particular, machine learning can efficiently allocate resources even in dynamically changing network environments based on real-time data. Therefore, AI technology can be utilized to provide hyper-connectivity and ultra-low latency.

[0135] In this case, AI / ML inference can be performed based on a combination of various devices. For example, the UE and the network can jointly perform AI / ML inference, and such an AI / ML model may be referred to as a two-sided AI / ML model or a two-sided model. In this case, the UE may perform the first part of the inference first, and the base station may perform the remaining inference, and vice versa. As another example, all inference may be performed by the UE, and such an AI / ML model may be referred to as a UE-side AI / ML model or a UE-side model.

[0136] In addition, life cycle management (LCM) for AI / ML models can be performed. Life cycle management may include model training, model deployment, model inference, model monitoring, and model updating. To this end, support may be required for data collection, model training, functionality / model identification, model delivery / transfer, model inference operations, functionality / model selection / enable / disable / fallback, functionality / model monitoring, model updating, and UE capabilities.

[0137] For example, AI / ML technology can be operated based on a functional framework such as FIG. 8. FIG. 8 illustrates an example of a functional framework for the application of AI / ML technology applicable to the present disclosure. First, a data collection function (810) generates training data (801), monitoring data (803), and / or inference data (805) containing processed input data by performing data preparation on input data collected from objects (e.g., UE, RAN node, network node, etc.). A model training function (820), having received the training data (801) from the data collection function (810), performs training on an AI / ML model using the training data (801) and provides the trained / updated model (813) to a model repository (840). The model repository (840) can store and retain the received trained / updated model (813).

[0138] A management function (830) may be used to control AI / ML model training. The management function (830) may control the operation of AI / ML models or AI / ML functions, or supervise their performance. To this end, the management function (830) may receive monitoring data (830) from the data collection function (810) and receive inference output (809) from the inference function (840). The management function (830) performs the role of managing the inference operation so that it can be performed efficiently based on the data received from the data collection function (810) and the inference function (840). That is, the management function (830) may transmit performance feedback or a retraining request (807) to the model training function (820) to improve the inference operation. Here, the performance feedback may be used to direct the learning goal or as a reward for reinforcement learning. Additionally, the management function (830) can provide management instructions (811) that instruct the inference function (840) to select AI / ML models or AI / ML-based functions to use, enable / disable them, or switch to non-AI / ML operations.

[0139] The inference function (840) generates an inference output (809) by performing inference and / or prediction using inference data (805) received by the data collection function (810). Here, the inference output (809) refers to the inference output of the AI / ML model used by the inference function (840), and the details of the inference output may vary depending on the use case. The AI / ML model used by the inference function (840) can be controlled by the management function (830). That is, the management function (830) can transmit a model transmission / delivery request signal (815) to the model repository function (850) to request the necessary AI / ML model, and the model repository function (850) can transmit the corresponding AI / ML model to the inference function (840) via a model transmission / delivery signal (817). Thus, the inference function (840) can perform inference using the AI / ML model (817) according to the received management instructions (811).

[0140] Additionally, the management function (830) can trigger or perform a specified task / action based on the inference output (809). Thus, the management function (830) can trigger a task / action on other objects (e.g., at least one UE, at least one RAN node, at least one network node, etc.) or on itself. Any one of the functions exemplified in FIG. 8 described above may be performed by two or more entities among the RAN, network node, network operator's OAM, or UE in collaboration. This may be referred to as a split AI operation.

[0141] To use an AI / ML model, not all of the functions (810 to 850) illustrated in FIG. 8 must be used, and the method of combining them is not limited to a specific method. Therefore, the functions (810 to 850) may be operated in an integrated manner, or some functions may be omitted. Furthermore, the functions (810 to 850) illustrated in FIG. 8 are not necessarily limited to being implemented as separate devices or apparatuses. For example, some or all of the functions (810 to 850) may be included in the processor (202) of FIG. 2. Additionally, the model storage function (850) may be included in the memory (204) of FIG. 2.

[0142] FIG. 9 illustrates an example of a procedure for utilizing an AI model applicable to the present disclosure. FIG. 9 illustrates a case where a model training function (820) is included in a network node and a model inference function (840) is included in a RAN node. Referring to FIG. 9, in step 1, RAN node 1 and RAN node 2 transmit input data (e.g., training data) for training an AI model to a network node. Here, RAN node 1 and RAN node 2 may also transmit data collected from a UE (e.g., UE measurements related to RSRP, RSRQ, SINR of a serving cell and neighboring cells, UE location, velocity, etc.) to the network node. In step 2, the network node trains the AI ​​model using the received training data. In step 3, the network node distributes / updates the AI ​​model to RAN node 1 and / or RAN node 2. RAN node 1 and / or RAN node 2 may continue to perform model training based on the received AI model. In this procedure, it is assumed that the AI ​​model is deployed / updated only to RAN Node 1. In Step 4, RAN Node 1 receives input data (e.g., inference data) for AI model inference from the UE and RAN Node 2. In Step 5, RAN Node 1 generates output data (e.g., prediction or decision) by performing AI model-based inference using the received inference data. In Step 6, if applicable, RAN Node 1 may transmit model performance feedback to the network nodes. In Step 7, RAN Node 1, RAN Node 2, and the UE (or 'RAN Node 1 and UE', or 'RAN Node 1 and RAN Node 2') perform an action based on the output data. For example, in the case of a load balancing action, the UE may move from RAN Node 1 to RAN Node 2. In Step 8, RAN Node 1 and RAN Node 2 transmit feedback information to the network nodes.

[0143] Network nodes can manage AI models based on feedback information regarding the inference results of AI models. For example, network nodes can perform additional training on AI models or generate additional information about AI models (e.g., performance information, accuracy information, etc.). If additional training is performed on AI models, network nodes can distribute the updated AI models to RAN node 1.

[0144] As explained with reference to Fig. 9, model training can be performed by network nodes, and inference using the model can be performed by RAN node 1. In other words, the model training and inference functions can be distributed. Generally, model training requires a large amount of computational resources because it involves optimization using large amounts of data and complex algorithms. In contrast, inference is a process of drawing conclusions about new data using an already trained model, and therefore requires relatively fewer computational resources compared to model training. Therefore, by using the procedure of Fig. 9, model training can be performed through network nodes if the computational resources of the UE or RAN nodes are insufficient. Additionally, security regarding the AI ​​model can be ensured because the AI ​​model is not exposed to the UE.

[0145] FIG. 9 illustrates a case where the model training function (820) is included in a network node and the model inference function (840) is included in a RAN node, but the present disclosure is not limited thereto. For example, if the computational resources of the RAN node are sufficient, both the model training function (820) and the model inference function (840) may be included in RAN node 1. In this case, RAN node 1 receives training data for training an AI model from the UE and RAN node 2. RAN node 1 trains the AI ​​model using the received training data. Subsequently, RAN node 1 receives inference data for AI model inference from the UE and RAN node 2. RAN node 1 generates output data by performing AI model-based inference using the received inference data. Based on the output data, the UE, RAN node 1, and RAN node 2 can perform communication-related operations (e.g., handover, cell change). Subsequently, the UE and RAN node 2 can transmit feedback regarding the operations to RAN node 1. Therefore, RAN Node 1 can train the AI ​​model and update the AI ​​model it will use through feedback information regarding the inference results of the AI ​​model. According to the aforementioned method, since signaling with the network is not required for AI model training and inference, the network load or the latency to train the AI ​​model or receive inference results can be reduced. Additionally, since the UE performs inference using the AI ​​model, the UE's personal information is not transmitted to network nodes, etc. Consequently, security regarding personal information can be enhanced.

[0146] As another example, the model training function (820) may be included in the RAN node, and the model inference function (840) may be included in the UE. The RAN node receives training data for training an AI model from the UE and trains the AI ​​model using the received training data. The RAN node distributes the trained AI model to the UE. The UE can generate output data by performing inference based on the received AI model. At this time, the data for inference can be received from the RAN node or data acquired by the UE itself can be used. The UE and the RAN node can perform communication-related operations based on the output data generated by inference. Subsequently, the UE can send feedback regarding the operation to the RAN node. Thus, through feedback information regarding the inference results of the AI ​​model, the RAN node can train the AI ​​model and distribute the updated AI model to the UE. According to the method described above, the load on the RAN node can be reduced by having the model training function (820) in the RAN node and the model inference function (840) in the UE perform inference. In addition, if the UE performs inference using data acquired independently, even if the UE loses its connection to the RAN node after receiving the AI ​​model, the UE can continue to perform inference using the received AI model and operate based on the inference results.

[0147] According to the aforementioned framework and procedure, an AI model can be trained and utilized in a wireless communication system. The model training function (820) and the model inference function (840) can be combined in various ways and are not necessarily limited to the case of FIG. 9. In the aforementioned framework and procedure, various data such as input data, training data, and inference data are introduced, and the specific details of the aforementioned data may vary depending on the task in which the AI ​​model is utilized. For example, information used in the various embodiments of the present disclosure described below may be included in the aforementioned data.

[0148] FIG. 10 illustrates an AI technology-based communication procedure applicable to the present disclosure. The detailed procedure illustrated in FIG. 10 may be combined with various embodiments of the present disclosure described below. For example, data generated according to various embodiments of the present disclosure may be used for operations (e.g., setup, training, inference, and / or data transmission / reception) in at least one of the detailed procedure illustrated in FIG. 10. As another example, the result of the inference illustrated in FIG. 10 may be used to transmit and / or receive data according to various embodiments of the present disclosure.

[0149] Referring to FIG. 10, in step S1001, at least one of the UE (1010), RAN node (1020), and network node (1030) performs an initial connection procedure. For example, in this step, at least one of an initial cell search operation, a system information acquisition operation, a random access operation, and a registration operation may be performed. In step S1003, at least one of the UE (1010), RAN node (1020), and network node (1030) performs a configuration procedure. Through the configuration procedure, parameters, resources, connections, and / or entities necessary to perform subsequent procedures at layers between the UE (1010) and the RAN node (1020) and / or at least one layer between the UE (1010) and the network node (1030) may be determined and / or created. At this time, the configuration procedure may be performed based on information, status, and / or characteristics of the AI ​​model used for subsequent training and inference.

[0150] In step S1005, at least one of the UE (1010), RAN node (1020), and network node (1030) performs a model training procedure. At least one of the UE (1010), RAN node (1020), and network node (1030) may collect training data and perform training using the training data. For example, the model training procedure may be performed as described with reference to FIG. 9. If an offline trained model is used, this step may be omitted.

[0151] In step S1007, at least one of the UE (1010), RAN node (1020), and network node (1030) performs a task using a trained model. That is, the task may be performed by the result of inference and / or prediction using the trained model. For example, the task may be a procedure belonging to a communication protocol, a preliminary operation for subsequent data transmission and / or reception, related to data transmission and / or reception, or related to data processing (e.g., encoding, decoding, etc.).

[0152] In step S1009, at least one of the UE (1010), RAN node (1020), and network node (1030) transmits and / or receives data. At this time, the result of the task performed in step 1007 may be used. In some cases, the task performed in step 1007 may include the transmission and / or reception of data, in which case this step may be omitted as it is part of step 1007.

[0153] Specific embodiments of the present disclosure

[0154] This disclosure proposes a method for efficiently configuring quantum state information to reduce the number of time bins required to construct single quantum state information. By utilizing the method proposed in this disclosure, the problem of difficulty in generating high-dimensional quantum information beyond a certain dimension due to laser pulse beam width constraints or modulator operating speed constraints can be mitigated. Furthermore, this disclosure proposes a method for configuring a single-photon-based high-dimensional quantum secure direct communication (QSDC) protocol using time bins and polarization, which are optical degrees of freedom that can be used stably with minimal changes in the wireless communication environment. This disclosure proposes a quantum state generation method and a detection method that can minimize the time required to generate a single quantum state to improve transmission speed. This disclosure can minimize the number of time bins required for quantum state configuration compared to existing techniques.

[0155] The abbreviations used in this disclosure are as follows.

[0156] - IM: intensity modulator

[0157] - PM: phase modulator

[0158] - PolM: polarization modulator

[0159] - ATT: attenuator

[0160] - BS: beam splitter

[0161] - QM: quantum memory or storage line

[0162] - OSW: optical switch

[0163] - MZI: mach-zehnder interferometer

[0164] - FPGA: field programmable gate array

[0165] - SPD: single photon detector

[0166] - VOA: variable optical attenuator

[0167] - QKD: quantum key distribution. Here, QKD refers to a secret key distribution technique based on quantum mechanics that guarantees absolute security.

[0168] - QSDC: quantum secure direct communication

[0169] - QBER: quantum bit error rate

[0170] - PC: polarization controller

[0171] In this disclosure, Alice may be referred to as a transmitter, a transmitting device, a transmitting node, or any other term having an equivalent technical meaning. Bob may be referred to as a receiver, a receiving device, a receiving node, or any other term having an equivalent technical meaning. Dead time refers to the minimum time interval during which the next signal can be measured after a single signal has been detected by a single photon detector. Furthermore, in this disclosure, Alice or Bob is not limited to a specific device or technology. For example, Alice or Bob may perform various roles such as a quantum communication terminal, a base station or repeater, or a device for controlling other equipment.

[0172] Quantum Security Direct Communication shares similarities with Quantum Key Distribution (QKD), which is used as a 4 / 5G secure communication technology, in that both are techniques for securely transmitting classical message information. However, they differ in that while QKD utilizes the quantum mechanical property of non-cloning to share symmetric secret key information—necessary for securely transmitting message information over a classical channel—between the sender and receiver via a quantum channel, QD shares the classical message information directly through the quantum channel rather than the secret key. Unlike QKD, QSDC does not generate leakage information related to the transmitted data, offering the advantage of higher security compared to QKD. QSDC can be classified into the DL04 technique, which uses a single-photon light source, and the Two-step QSDC technique, which uses an entangled light source. To ensure security, the DL04 technique utilizes a round-trip structure for information transmission, while the Two-step QSDC technique utilizes a structure that divides information transmission into two stages. The specific protocols for these two techniques are described below.

[0173] Basic structure of QSDC

[0174] (1) DL04 QSDC protocol

[0175] FIG. 11 illustrates an example of a device for transmitting or receiving quantum information in a DL04 QSDC protocol according to one embodiment of the present disclosure. In FIG. 11, the transmitter is labeled Alice (1110) and the receiver is labeled Bob (1120). The SR (storage line) is an optical delay line that acts as a quantum memory and can be replaced by other forms of quantum memory. The CE (checking eavesdropping) is a device for checking for the presence of an eavesdropper. The CM (coding message) is a device for encoding classical message information to be transmitted from Alice (1110) to Bob (1120). Source refers to a device that generates an initial quantum state, measurement refers to a device capable of measuring the quantum state, and M1 and M2 refer to reflective mirrors.

[0176] The DL04 QSDC technique is configured based on a single photon as shown in FIG. 11, and the receiver, Bob (1120), transmits a single photon to the transmitter, Alice (1110). Here, the single photon can be generated as an initial quantum state using an ODF such as polarization, phase, and time. A process of estimating the quantum bit error rate (QBER) using some of the transmitted single photons is performed first. The process of estimating the QBER is as follows.

[0177] Bob (1120) transmits location information to Alice (1110) via a classical channel to be used for QBER estimation. Alice (1110) transmits measurement information of the location to Bob (1120). Bob (1120) calculates the QBER by comparing the initial quantum state measured by Alice (1110) with the initial quantum state generated by Bob (1120). The presence of an eavesdropper can be confirmed by comparing the calculated QBER with a QBER threshold. For example, if the calculated QBER is greater than a preset threshold, it can be considered that an eavesdropper is present.

[0178] Additionally, while QBER estimation is being performed, the remaining initial quantum states not used for QBER estimation are stored in the SR, which acts as a quantum memory. QBER estimation requires enough time to exchange information through the classical channel. Therefore, if the length of the quantum channel and the length of the classical channel are the same, the length of the SR must be greater than twice the length of the quantum channel. If it is confirmed through QBER estimation that there are no eavesdroppers in the quantum channel, Alice (1110) encodes the classical message information she intends to transmit via the CM using the initial quantum state. The encoded quantum state is transmitted to Bob (1120) via the quantum channel. At this time, an attempt may be made by an eavesdropper to intercept the information in the quantum channel. However, since the eavesdropper cannot know the information regarding the initial quantum state transmitted via the quantum channel, even if the eavesdropper intercepts the encoded quantum state, they only obtain information in a meaningless sequence of random numbers and cannot recover the message information from it. Therefore, the safety of the transmitted message information can be ensured. Since Bob (1120) knows the initial quantum state he created, he can recover the classical message information sent by Alice (1110) by comparing the received encoded quantum state with the initial quantum state. Single-photon-based QSDC techniques are being developed as methods that can transmit 1 bit of message information through a single quantum state.

[0179] (2) Two-step QSDC protocol

[0180] FIG. 12 illustrates an example of a device for transmitting or receiving quantum information in a two-step QSDC protocol according to one embodiment of the present disclosure. In FIG. 12, the transmitter is labeled Alice (1210) and the receiver is labeled Bob (1220). SR1 to SR4 are optical delay lines that serve as quantum memory and may be replaced with other forms of quantum memory. CE1 and CE2 are devices for checking for the presence of an eavesdropper. CM (coding message) is a device for encoding classical message information to be transmitted from Alice (1210) to Bob (1220). EPR source refers to a device for generating entangled quantum pairs, and Bell-basis measurement refers to a device capable of measuring entangled quantum pairs. Referring to Fig. 12, the quantum entanglement-based QSDC technique is derived from the super dense coding technique and can safely transmit 2 bits of classical information using four types of entangled photon pairs (EPR-pairs) as shown in [Equation 1] below.

[0181]

[0182] In Two-step QSDC, unlike super-dense coding techniques, entangled photon pairs are not transmitted all at once to ensure security; instead, they are transmitted in two stages through an upper quantum channel and a down quantum channel. For an eavesdropper to intercept an entangled light source, they must know the information from both ends of the entangled photon pair to determine the transmitted information through measurement. To prevent eavesdropping, the Two-step QSDC technique employs a method where one particle of the entangled photon pair is transmitted first through the upper quantum channel, and security against eavesdroppers is verified beforehand. Only after security is guaranteed is the remaining particle of the photon pair, which contains the intended message information, transmitted through the down quantum channel. Even if an eavesdropper intercepts the particle transmitted through the down quantum channel, it is impossible to deduce the message information from the intercepted particle data because they do not know the state of the entangled particle transmitted through the upper quantum channel. Finally, Bob (1220) can perform a Bell state measurement using the two entangled particles received and determine what message the transmitter sent based on which of the four Bell states it was measured to be.

[0183] single photon based high-dimensional QSDC

[0184] Among QSDC techniques, quantum entanglement-based QSDC protocols can enable high-dimensional transmission of 2 bits / quantum state or higher by expanding the number of entangled particles. However, in single-photon-based QSDC techniques, a technique for transmitting high-dimensional information using time bins and phases can be considered. FIGS. 13a and 13b illustrate examples of devices for transmitting or receiving quantum information using time bins and phases in a QSDC technique according to an embodiment of the present disclosure. In FIG. 13a, the transmitter is labeled Alice (1310) and the receiver is labeled Bob (1320). Referring to FIG. 13a, the receiver Bob (1310) generates an initial quantum signal containing initial quantum states by passing a pulse generated from a laser through an intensity modulator (IM), a phase modulator (PM), and a polarization modulator (PolM). It is then transmitted to the transmitter Alice (1310) through a forward quantum channel.

[0185] Alice (1310) uses some pulses of the initial quantum signal to detect and check for the presence of an eavesdropper, and uses some pulses to perform encoding. Encoding can be performed through a differential time encoder as shown in FIG. 14b. Alice (1310) transmits the encoded pulses to Bob (1320) through a reverse quantum channel. Bob (1320) can perform measurements based on the received encoded pulses and perform decoding by comparing the measurement results with the initial quantum state he created.

[0186] FIG. 14 illustrates an example in which N-dimensional basis states are generated based on time bins and phases according to an embodiment of the present disclosure. Bob generates N-dimensional initial quantum states using time bins and phases as shown in FIG. 14. First, the time states corresponding to the Z basis states can be configured such that N time bin states have an orthogonal relationship with each other based on the location information of the time bin where a single photon exists. Subsequently, the X basis states can be configured based on phases as shown in [Equation 2] so that they have a mutually unbiased base relationship with the Z basis states to ensure safety.

[0187]

[0188] Here, mutually unbiased basis relations refer to a relationship where, when a specific N-dimensional basis state is measured by another basis, it is measured as the same value with only a probability of 1 / N and as an incorrect value with a probability of (N-1) / N. The security of quantum communication protocols is guaranteed through mutually unbiased basis relations.

[0189] In FIG. 13a and 13b, the optical signal generated by the laser passes through an intensity modulator (IM) and a phase modulator (PM), and is generated into one of two states. Bob can pass the signal that has passed through the IM and PM through an ATT to attenuate it to a single-photon energy level. Bob transmits the generated single-photon-based initial quantum states to Alice through a forward quantum channel. Alice estimates the QBER using some of the received information. Here, to measure the quantum information used for QBER estimation, a method is applied in which the Z ground state is detected based on the time when single-photon information is measured by the single-photon detector (SPD). The X ground states are measured by utilizing the fact that the path measured by constructive interference differs for each state caused by interference of phase information.

[0190] An interferometer called an MZI (mach-zehnder interferometer) can be used to perform the measurement. To measure the N-dimensional X ground state, N-1 MZIs and N SPDs are required. QBER estimation is performed through the measurement of the initial quantum states, and if the QBER does not exceed a threshold, the initial quantum state received through the forward quantum channel can be guaranteed to be safe information that has not been intercepted, so the next process is continued. However, if the QBER exceeds the threshold, it indicates the presence of an eavesdropper, so the transmission process is stopped.

[0191] Information among the initial quantum states that was not used for QBER estimation is stored in quantum memory (QM), and once safety is guaranteed after the QBER estimation is complete, the initial quantum states stored in QM can be used. Alice generates a classical message she wishes to send and creates a codeword for the classical message by encoding the classical message. The generated codeword ┗ log2N ┛ A message can be encoded into an initial quantum state by dividing it into bits and applying different time delays depending on the message value (i.e., 00...0 to 11...1). Alice transmits the encoded quantum state to Bob via a backward quantum channel. After receiving the encoded quantum state, Bob measures the X or Z basis state by changing the measurement method using an optical switch (OSW) according to the basis measurement method that matches the basis type of the initial quantum state he initially generated. Some of the measurement results are used to estimate the error rate of the backward quantum channel, and the remaining information is used for message transmission. The received encoded state is converted into binary sequence information corresponding to the difference between the result after measurement and the initial quantum state. The converted binary sequence information can be restored as message information after error correction is performed through the decoding process of classical error correction codes.

[0192] In the aforementioned single-photon-based high-dimensional QSDC protocol, a long time is allocated for the configuration of a single quantum state. FIGS. 15a and FIGS. 15b illustrate an example of a method for configuring the time and phase states of an N-dimensional QSDC according to an embodiment of the present disclosure. In the single-photon-based high-dimensional QSDC protocol, time intervals may be allocated in the time domain as shown in FIGS. 15a and FIGS. 15b. Specifically, when generating an N-dimensional quantum state, a first time interval (1501, 1504) required for generating an initial quantum state may be allocated for a length of Nτ, a second time interval (1502, 1505) required for message encoding may be allocated for a length of (N-1)τ, and a third time interval for securing the detection of consecutive quantum states may be allocated for a length of (N-1)τ. Thus, a total of (3N-2)τ time is allocated to generate a single quantum state in order to generate an N-dimensional quantum state. Here, the third time interval (1503, 1506) is described as being required for a length of (N-1)τ from the end of the second time interval (1502, 1505) to secure the dead time Nτ, which is the minimum measurement time interval of the detector, but the third time interval (1503, 1506) can change dynamically depending on the quantum channel environment.

[0193] Considering the dead time Nτ, if the time allocated to generate an N-dimensional quantum state can be configured to be as close as possible to the dead time Nτ, the transmission speed of quantum information can be increased.

[0194] Referring to FIGS. 15a and 15b, the single-photon-based N-dimensional QSDC protocol uses 3N-2 time bins to construct information using a single quantum state; therefore, photons must be positioned within short time bin intervals, and phase modulation must be performed at high speed. Consequently, difficulties may arise in implementing a device that generates quantum states for transmitting high-dimensional information. Specifically, photons generated by a laser must be positioned within time bins with narrow time intervals. As the interval between time bins narrows, laser equipment with a narrow beam width and a high repetition rate must be used. Furthermore, as the dimension increases, time bins are generated with narrower time intervals; since phase modulation must be performed at high speed to generate phase states, speed constraints on the phase modulator may exist. For convenience of explanation, the device transmitting the message is described below as the sender, or Alice, acting as a terminal or station, and the receiver, or Bob, acting as a base station or server, but this is not limited thereto. For example, the sender may be a base station and the receiver may be a terminal. As another example, Alice and Bob may both be terminals, and the methods proposed in this disclosure may be used to perform communication between the terminals.

[0195] The following describes a method for efficiently configuring a high-dimensional quantum security direct communication protocol in terms of transmission speed, capable of securely transmitting information of 2 bits / quantum state or more based on time bins and polarization. The entire QSDC protocol can proceed in a sequence similar to the DL04 protocol, a single-photon-based QSDC protocol. First, the receiver transmits initial quantum states to the transmitter using a forward quantum channel, and the transmitter estimates the QBER using some of the received initial quantum states. If the security of the information transmitted through the forward quantum channel is guaranteed, the transmitter generates encoded quantum states by performing message encoding on the initial states. The encoded quantum states are transmitted to the receiver. The receiver measures the encoded quantum states received through the reverse quantum channel and compares the corresponding information with the initial quantum states it generated. Based on the comparison results, the receiver can obtain the message information transmitted by the transmitter. For the sake of convenience of explanation, an example of executing a 4-dimensional QSDC protocol among high-dimensional QSDC protocols is described below, but it is not limited to this. The procedures of the 4-dimensional QSDC protocol described below can be applied to the high-dimensional QSDC protocol in a similar manner.

[0196] FIGS. 16a and FIGS. 16b illustrate examples of devices for performing a four-dimensional QSDC protocol using time and polarization according to one embodiment of the present disclosure. FIG. 16a illustrates examples of devices included in a receiver, Alice. Alice includes a QBER estimation part (1711) and a message encoding part (1712). FIG. 16b illustrates examples of devices included in a transmitter, Bob. Bob may include an initial state generation part (1721), a message decoding part, a QBER estimation part, and a recovery part (1722). The four-dimensional quantum security direct communication protocol may be performed through the following first to fourth steps.

[0197] Step 1: High-dimensional initial quantum state generation step

[0198] The receiver Bob generates an initial quantum signal based on pulses generated from the laser. The receiver Bob generates an initial quantum signal containing initial quantum states by passing the pulses generated from the laser through an intensity modulator (IM), a phase modulator (PM), and a polarization modulator (PolM). The initial quantum box states are the four Z ground states, |Z i 〉 and the four X ground states, |X i It may include >. Initial quantum states can be expressed as shown in [Equation 3] below.

[0199]

[0200] In [Equation 3], H means 0°, V means 90°, A means -45°, and D means 45°.

[0201] FIG. 17 illustrates an example of an initial quantum state included in an initial quantum signal according to one embodiment of the present disclosure. The four states on the left of FIG. 17 are Z ground states, and the four states on the right are X ground states.

[0202] First, the method for generating Z ground states is described. In a 4-dimensional QSDC, |Z0〉 and |Z1〉 are configured so that a single photon is assigned to the second time bin by IM. Subsequently, vertical or horizontal polarization is applied to the second time bin using PolM. Polarization is applied differently to |Z0〉 and |Z1〉. The reason for applying different polarization is to ensure that the paths are separated when measuring |Z0〉 and |Z1〉. That is, |Z0〉 and |Z1〉, having passed through a polarized beam splitter (PBS), have their paths separated and can be detected by detectors located on different paths, thus allowing the states of |Z0〉 and |Z1〉 to be distinguished.

[0203] |Z2〉 and |Z3〉 are configured so that a single photon is assigned to the first time bin by IM so that they can be distinguished from |Z0〉 and |Z1〉. Subsequently, vertical or horizontal polarization is applied to the first time bin using PolM. Through the aforementioned method, four Z ground states can be generated. Polarization is applied differently to |Z2〉 and |Z3〉.

[0204] The method for generating X ground states is described below. In a 4-dimensional QSDC, |X0〉 and |X1〉 are configured such that a single photon is assigned to either the first time bin or the second time bin. The probability of a single photon being assigned to the first time bin and the second time bin can be set to be equal. Subsequently, |X0〉 is configured via PM so that the relative phase difference between the first time bin and the second time bin is zero. Then, polarizations of -45° and 45° are applied to each of the two time bins via PolM. Specifically, polarization of -45° can be applied to the first time bin, and polarization of 45° can be applied to the second time bin. |X1〉 is configured via PM so that the relative phase difference between the first time bin and the second time bin is 180°. Subsequently, polarizations of -45° and 45° are applied to each of the two time bins using PolM.

[0205] |X2〉 and |X3〉 are identical in that a single photon is assigned to either the first time bin or the second time bin. The positions of polarization applied to each of the two time bins can be swapped so that |X2〉 and |X3〉 can be distinguished from |X0〉 and |X1〉. Thus, 45° polarization can be applied to the first time bin and -45° polarization can be applied to the second time bin.

[0206] Referring to FIG. 17, a single ground state can be composed of four time bins. The first two time bins can be used to generate the aforementioned initial quantum state. The remaining time bins can be used to eliminate losses during the encoding and detection processes caused by the dead time of the SPD. Specifically, a third time bin can be used for message encoding. The Z ground and X ground states are measured through the first to third time bins. For the measurement to be performed, a time interval equal to the dead time must be guaranteed between consecutive quantum states. Therefore, a fourth time bin is required. The information signal containing the generated initial quantum state is attenuated to a single-photon level energy unit via VOA and then transmitted to Alice, the sender, via a forward quantum channel.

[0207] Phase 2: QBER Estimation Phase

[0208] FIG. 18 illustrates examples of devices included in a QBER estimation part according to one embodiment of the present disclosure. The QBER estimation part (1611) of FIG. 16a may be composed of the devices shown in FIG. 18. In FIG. 18, the polarized beam splitter is labeled 'PBS', the time-to-digital converter is labeled 'TDC', the single photon detector is labeled 'D', the polarization controller is labeled 'PC', and the beam splitter is labeled 'BS'. As in FIG. 16a, the QBER estimation part (1611) of FIG. 18 may utilize 10% of the initial quantum states randomly selected from the total initial quantum states by passing an information signal containing initial quantum states through a 1:9 BS, where Alice (1610), the transmitter, passes the information signal containing the initial quantum states. At this time, the remaining 90% of the initial quantum states may be stored in quantum memory. Alice can perform the QBER estimation process using the devices of Fig. 18 with randomly selected initial quantum states.

[0209] In the QBER estimation process, the initial quantum state included in the received information signal is randomly selected through the first BS (1801). The initial quantum state that passes through the first BS (1801) is measured as the Z basis when output through the upper path and as the X basis when output through the lower path.

[0210] In the following, the case of the Z basis measurement, which is the upper path, is described first. When the initial quantum state, which is the Z basis state, passes through the first PBS (1811), the initial quantum state is detected by the D1 (1821) detector if the polarization information is H, and the initial quantum state is detected by the D2 (1822) detector if the polarization information is V. Afterward, when the path in which the initial quantum state was detected and the time of detection are transmitted to the TDC (1831), the TDC can distinguish which of the four Z basis states was transmitted as shown in [Table 2] below.

[0211] Z basis stateResponse of detector / time|Z0〉D1(at t2)|Z1〉D2(at t2)|Z2〉D1(at t1)|Z3〉D2(at t1)

[0212] In [Table 2], t1 represents the case detected in the first time bin, and t2 represents the case detected in the second time bin. Since Alice can distinguish the detected path and detection time as in [Table 2], she can distinguish four ground states. Below, the case of the X ground measurement, which is the lower path, is described. In the case of the quantum state of the X ground, it can move along four paths, and four states can be distinguished based on the results detected at D3 (1823) to D6 (1826). First, when the initial quantum state passes through the second BS (1802), it is transmitted to one of two paths with half probability.

[0213] If transmitted via the upper path, measurements corresponding to |X2〉 and |X3〉 are performed, and if transmitted via the lower path, measurements corresponding to |X0〉 and |X1〉 are performed.

[0214] For measurements corresponding to |X0〉 and |X1〉, the second PC (1842) converts the diagonal polarization component of the initial quantum state of the X basis into orthogonal polarization by rotating it 45°. Afterward, when the quantum state converted into orthogonal polarization passes through the third PBS (1813), the signal located in the first time bin is polarized to V and passes through a long path with a delay time of τ, which is one time bin interval, and the signal located in the second time bin is polarized to H and passes through a short path. The signals passing through the two paths meet simultaneously at the fourth BS (1804) and cause interference, and the result is measured at the time corresponding to the second time bin. Depending on the phase difference between the two signals during interference, a signal may be detected at one of the detectors D5 (1825) and D6 (1826).

[0215] For measurements corresponding to |X2〉 and |X3〉, the first PC (1841) converts the diagonal polarization component of the initial quantum state of the X basis into orthogonal polarization by rotating it 45°. Subsequently, when the quantum state converted into orthogonal polarization passes through the second PBS (1812), the signal located in the first time bin is polarized to H and passes through a long path with a delay time of τ, which is one time bin interval, and the signal located in the second time bin is polarized to V and passes through a short path. The signals passing through the two paths meet simultaneously at the third BS (1803) and cause interference, and the result is measured at the time corresponding to the second time bin. Depending on the phase difference between the two signals during interference, a signal may be detected at one of the detectors D3 (1823) and D4 (1824). Which of the initial quantum states of the Z basis has been transmitted can be confirmed using [Table 3] below.

[0216] X basis stateResponse of detector / time|X0〉D5(at t2)|X1〉D6(at t2)|

[0217] In [Table 3], t1 refers to the case detected in the first time bin, and t2 refers to the case detected in the second time bin. Alice can estimate QBER by exchanging measurement basis information and measurement results with Bob through a classical channel based on the measurement results of the initial quantum state. Based on QBER and a preset threshold, it can be determined whether it is safe from eavesdropper attacks. For example, if QBER is greater than the preset threshold, quantum communication may be interrupted. If QBER is less than the preset threshold, it may be determined that it is safe from eavesdroppers, and the message encoding process described below may proceed.

[0218] Step 3: Message Encoding Step

[0219] FIG. 19 illustrates examples of devices included in a message encoding part according to one embodiment of the present disclosure. The message encoding part of FIG. 16a may be composed of the devices shown in FIG. 19. In FIG. 19, it is assumed that the message encoding part stores the remaining initial quantum states that are not transmitted to the QBER part in QM (1901). For convenience of explanation, it is assumed below that 10% of the initial quantum states, arbitrarily selected via 1:9 BS as in FIG. 16a, are transmitted to the QBER part, and the remaining 90% of the quantum states are stored in QM (1901).

[0220] If the N-dimensional initial quantum states received by the sender Alice through the forward quantum channel are corrected to be safe from eavesdroppers through the second stage QBER estimation, Alice can use the remaining 90% of the initial quantum states stored in QM (1901) to perform encoding of the classical message and generate encoded quantum states.

[0221] Alice generates a classic message to be sent and creates a codeword for the classic message by encoding the classic message for error correction. Alice uses the generated codeword. ┗ log2N ┛ After dividing into bits, message encoding is performed by applying a time delay and polarization or phase modulation corresponding to the value.

[0222] Devices for encoding 2-bit codeword information into a 4-dimensional initial photon state can be configured as shown in FIG. 19. First, for the Z basis state, the control unit FPGA (1902) transmits control signals corresponding to codeword bits via OSW (1903) and PolM (1904). The initial quantum state of the Z basis stored in the quantum memory can be converted into an encoded quantum state depending on polarization and the degree of delay of the transmission path. Next, for the X basis state, the control unit FPGA (1902) transmits control signals corresponding to codeword bits via OSW (1903) and PM (1905). The initial quantum state of the X basis stored in the quantum memory can be converted into an encoded quantum state depending on phase and the degree of delay of the transmission path.

[0223] Alice can receive information regarding the basis of the initial quantum state stored in the QM used for message encoding from Bob during the second step, QBER estimation. Specifically, when Alice receives information on the entire basis of the initial quantum states from Bob, she can know the basis of the initial quantum state stored in the QM. Message encoding can be performed on the initial quantum state of the X basis and the initial quantum state of the Z basis, but the initial quantum states to be encoded can be selected by the operator. The rules for encoding the initial quantum states of the Z basis can be expressed as shown in [Table 4] below.

[0224] codeword bitstime delayPolarization(first time bin, second time bin)000(0°, 0°)010(90°, 90°)10τ(0°, 0°)11τ(90°, 90°)

[0225] As shown in [Table 4], the Z ground state has a polarization state rotation of 0° or 90° applied to the first and second time bins by PolM (1904) depending on the value of the codeword 2 bits, followed by a time delay path selected by OSW (1903). That is, Alice converts the initial quantum state into an encoded quantum state by performing encoding based on the time delay and polarization state corresponding to the codeword.

[0226] codeword bitstime delayPhase(first time bin, second time bin)000(0, 0)010(π, 0)10τ(0, 0)11τ(π, 0)

[0227] As shown in [Table 5], the X ground state applies a phase of 0 or π to the first and second time bins in the PM depending on the value of the 2-bit codeword, and then determines the time delay path selected by the OSW. That is, Alice can convert the initial quantum state into an encoded quantum state by performing encoding based on the phase and time delay corresponding to the codeword. The converted encoded quantum state can be transmitted to Bob through the reverse quantum channel.

[0228] Step 4: Message Recovery Step

[0229] FIG. 20 illustrates examples of devices for performing message decoding according to one embodiment of the present disclosure. In FIG. 20, it is assumed that the receiver Bob receives an encoded quantum state from the transmitter Alice via a reverse quantum channel. The received encoded quantum state is determined by the OSW (2061) to be transmitted via a specific path. The OSW (2061) can be controlled based on information regarding the initial quantum state initially generated by Bob, which is stored in the control device FPGA (2051). Thus, all received encoded quantum states can be measured as a correct basis.

[0230] If the encoded quantum state is a Z ground state, it is transmitted to the first PBS (2011) via the path at the top of FIG. 20. The encoded state transmitted to the first PBS (2011) can be detected by detector D7 (2021) or detector D8 (2021), respectively, depending on whether the polarization component is H or V. Subsequently, when the path where the initial quantum state was detected and the time of detection are transmitted to the TDC (2031), the TDC (2031) can distinguish which of the four Z ground states the quantum state was transmitted as shown in [Table 6] below.

[0231] initial statemessageencoded statedtector(time) 00 D7( at t2)01 D8( at t2)10 D7( at t3)11 D8(at t3) 00 D8( at t2)01 D7(at t2)10 D8( at t3)11 D7(at t3) 00 D7( at t1)01 D8( at t1)10 D7( at t2)11 D8(at t2) 00 D8( at t1)01 D7(at t2)10 D8( at t2)11 D7(at t2)

[0232] Therefore, Bob can recover the message information transmitted by Alice by comparing the information regarding the initial quantum state of the Z basis initially generated with the measurement results of the encoded quantum state. If the encoded quantum state is the X basis state, it is transmitted to the second PBS (2012) or the third PBS (2013) via the lower path of FIG. 20. In the path connected to D11 (2025) and D12 (2026), |X0〉 or |X1〉 is detected, and in D9 (2023) and D10 (2024), |X2〉 and |X3〉 are detected. The encoded quantum state of the X basis can be measured in the same way as the method of measuring the quantum state of the X basis in the second stage, the aforementioned QBER detection step. Specifically, PCs (2041, 2042) convert the diagonal polarization component of the encoded quantum state of the X basis into orthogonal polarization by rotating it 45°. Subsequently, the quantum state converted to orthogonal polarization passes through PBSs (2012, 2013), travels along paths of different lengths, and meets simultaneously to cause interference. During interference, a signal can be detected at detectors (2023 to 2026) depending on the difference in phases between the two signals. Based on the initial quantum state information stored in Bob and the detection results, the encoded quantum state of the X basis can be determined. [Table 7] below shows the values ​​of message information determined by the initial quantum state of the X basis and the measurement results.

[0233] initial statemessageencoded statedtector(time)|X0〉 00 D11( at t2)01 D12(at t2)10 D11( at t3)11 D12(at t3)|X1〉 00 D12(at t2)01 D11( at t2)10 D12(at t3)11 D11(at t3)|X2〉 00 D9( at t2)01 D10( at t2)10 D9( at t3)11 D10( at t3)|X3〉 00 D10( at t2)01 D9(at t2)10 D10( at t3)11 D9(at t3)

[0234] At this time, some of the detected encoded Z and X basis quantum states are used for the QBER estimation of the reverse quantum channel. The quantum states used for QBER estimation can be randomly selected, and by exchanging the basis of the encoded quantum states with the measurement results, the presence of an eavesdropper and the error rate of the channel can be estimated. The presence of an eavesdropper and the error rate of the channel can be used in the decoding process. FIG. 21 illustrates an example in which a receiving node performs a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure. FIG. 21 illustrates a method performed by a device included in a quantum network (e.g., UE (1010), RAN node (1020), network node (1030) of FIG. 10, Bob (1620) of FIG. 16b). In the description with reference to FIG. 21, the operating entity is referred to as the receiving node. The receiving node is a node that transmits specific information using quantum communication and can be various communication devices such as terminals, base stations, and repeaters. For the sake of convenience of explanation, the receiving node is described below as performing the role of a terminal, but is not limited thereto.

[0235] Referring to FIG. 21, in step S2101, the receiving node performs an initial connection procedure. The receiving node performs the initial connection procedure with the transmitting node and can establish a connection with the transmitting node. To perform the initial connection procedure, the receiving node may receive system information from the receiving node. The system information may be transmitted via the master information block (MIB) and the system information block (SIB). The initial connection procedure may include a random access procedure. The receiving node transmits a signal for initial connection (e.g., a random access preamble) to the transmitting node and receives a response signal for the signal for initial connection from the transmitting node.

[0236] In step S2103, the receiving node transmits a first signal containing an initial quantum state generated based on time bins and polarization. The initial quantum state may be generated based on a first basis and a second basis. Here, the first basis may refer to the aforementioned Z basis, and the second basis may refer to the aforementioned X basis. In the following, the first basis and the second basis may also be used with the same meaning. If a 4-dimensional QSDC protocol is performed, the initial quantum state may be determined as one of the four quantum states of the first basis (e.g., first to fourth states) and the four quantum states of the second basis (e.g., fifth to eighth states). The initial quantum state may be generated within the first time bin and the second time bin among the first time bin, the second time bin, the third time bin, and the fourth time bin. Here, encoding may be performed on the third time bin. The fourth time bin can be used to secure dead time and may be referred to as a guard time bin. Specifically, initial quantum states can be generated in the form shown in FIG. 17. For example, in the case of the first state, a single photon is assigned to the second time bin, and horizontal polarization can be applied to the second time bin. The time interval τ assigned to each time bin can be set to half of the detector's dead time.

[0237] In step S2105, the receiving node receives a second signal containing an encoded quantum state. The receiving node may perform a measurement of the received second signal. Through the measurement of the second signal, the receiving node may obtain information related to the encoded quantum state. To perform the measurement, the receiving node may determine a detection path corresponding to the second signal based on the basis of the initial quantum state. Here, the detection path may be controlled via an optical switch. Specifically, if the initial state is generated based on the first basis, the second signal may be detected using a polarized beam splitter (PBS) and two single photon detectors (SPDs). On the other hand, if the initial state is generated based on the second basis, the second signal may be detected using two polarization controllers (PCs), two polarized beam splitters (PBSs), two delay lines, two beam splitters (BSs), and four single photon detectors (SPDs).

[0238] In step S2107, the receiving node performs decoding of the second signal. At this time, decoding may be performed based on an initial quantum state, a time bin in which the second signal was detected, and a detector in which the second signal was detected. If the quantum state included in the second signal is generated as a first basis, the receiving node can obtain information about the codeword transmitted by the transmitting node using the encoded quantum state. On the other hand, if the quantum state included in the second signal is generated as a second basis, the receiving node can determine the presence of an eavesdropper in the reverse quantum channel based on the detector in which the second signal was detected and the initial quantum state.

[0239] FIG. 22 illustrates an example in which a transmitting node performs a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure. FIG. 22 illustrates a method performed by a device included in a quantum network (e.g., UE (1010), RAN node (1020), network node (1030) of FIG. 10, Alice (1610) of FIG. 16a). In the description with reference to FIG. 22, the operating entity is referred to as the transmitting node. The transmitting node is a node that transmits specific information using quantum communication and can be various communication devices such as a terminal, base station, or repeater. For convenience of explanation, the transmitting node is described below as performing the role of a base station and the receiving node as performing the role of a terminal, but is not limited thereto.

[0240] Referring to FIG. 22, in step S2201, the transmitting node performs an initial connection procedure. The transmitting node performs the initial connection procedure with the receiving node and can establish a connection with the receiving node. To perform the initial connection procedure, the transmitting node may transmit system information to the receiving node. The system information may be transmitted via the master information block (MIB) and the system information block (SIB). The initial connection procedure may include a random access procedure. The transmitting node receives a signal for initial connection (e.g., a random access preamble) from the receiving node and can transmit a response signal for the signal for initial connection to the receiving node.

[0241] In step S2203, the transmitting node receives a first signal from the receiving node containing an initial quantum state generated based on a time bin and polarization. The initial quantum state may be generated based on at least one time bin to which a single photon is assigned among a plurality of time bins and polarization applied to said at least one time bin. The initial quantum state may be generated based on a first basis and a second basis. Here, the first basis may refer to the aforementioned Z basis, and the second basis may refer to the aforementioned X basis. The transmitting node may estimate the QBER using the first signal. A specific procedure will be described later.

[0242] In step S2205, the transmitting node generates a second signal containing an encoded quantum state. The encoded quantum state can be generated using an initial quantum state. Here, if the initial quantum state is generated based on a first basis, the encoded quantum state can be generated based on polarization and the degree of delay of the transmission path. Specifically, the initial quantum state can be moved to a different time bin through a delay line capable of delaying the transmission time, and polarization can be applied to the initial quantum state. If the initial quantum state is generated based on a second basis, the encoded quantum state can be generated by performing an encoding process using time delay and phase on the initial quantum state. The encoded quantum state can be included in the second signal and transmitted.

[0243] In step S2207, the transmitting node transmits a second signal to the receiving node. The second signal may include an encoded quantum state. The initial quantum states included in the second signal may be used for estimating the QBER of the reverse quantum channel. If the QBER estimated based on the second signal is higher than a threshold value, the receiving node may determine that an eavesdropper is present. If it is determined that an eavesdropper is present, the QSDC protocol may be terminated.

[0244] FIG. 23 illustrates an example in which a transmitting node determines the presence of an eavesdropper in a QSDC protocol using time bins and polarization according to one embodiment of the present disclosure. FIG. 23 illustrates a method performed by a device included in a quantum network (e.g., UE (1010), RAN node (1020), network node (1030) of FIG. 10, Alice (1610) of FIG. 16a). In the description with reference to FIG. 23, the operating entity is referred to as the transmitting node. The transmitting node is a node that transmits specific information using quantum communication and can be various communication devices such as a terminal, base station, or repeater. For convenience of explanation, the transmitting node is described below as performing the role of a base station and the receiving node as performing the role of a terminal, but is not limited thereto.

[0245] Referring to FIG. 23, in step S2301, the transmitting node receives a first signal from the receiving node containing an initial quantum state generated based on time bins and polarization. Here, the first signal may include an initial quantum state generated based on a first basis or a second basis.

[0246] In step S2303, the transmitting node estimates QBER based on the first signal. QBER can be estimated using some of the initial quantum states included in the first signal. The remaining initial quantum states can be stored in quantum memory for safety checks through QBER estimation. The paths of the initial quantum states used for QBER estimation, which are detected by detectors via a beam splitter, can be arbitrarily determined. For convenience of explanation, it is assumed below that the initial quantum state consists of four dimensions. If the initial quantum state is the first basis, the initial quantum state can be detected through one of two detectors, and the measured initial quantum state of the first basis can be derived based on the detected time bin index and the detector where the detection occurred. If the initial quantum state is the second basis, the initial quantum state can be detected through one of four detectors. Therefore, the state of the initial quantum states of the second basis can be distinguished by which detector detected them. The transmitting node can receive information about the initial quantum state generated by the receiving node from the receiving node, and can estimate the QBER by comparing the received information about the initial quantum state with the initial quantum state measured based on detector and time information.

[0247] In step S2305, the transmitting node determines whether an eavesdropper is present. If the QBER is greater than a preset threshold, the transmitting node may determine that an eavesdropper is present in the forward quantum channel. If it is determined that an eavesdropper is present, the QSDC protocol may be terminated.

[0248] The method by which the receiving node estimates QBER can be performed in a manner similar to the procedure described in FIG. 23. That is, the receiving node receives a second signal from the transmitting node and can estimate QBER using some of the quantum states included in the second signal. At this time, the quantum states used for estimating QBER can be determined based on the basis. Therefore, some selected quantum states among the quantum states included in the second signal can be used for QBER estimation. QBER can be estimated using some of the quantum states of the second basis. The procedure for measuring the quantum states of the first basis or the second basis can be performed in the same manner as the aforementioned step S2303. Therefore, the quantum states of the first basis or the second basis can be estimated based on the measured detector information and the measured time information. If the QBER estimated by the receiving node is greater than a preset threshold, it can be determined that an eavesdropper is present in the reverse quantum channel. If it is determined that an eavesdropper is present, the QSDC protocol may be terminated.

[0249] FIG. 24 illustrates an example of signaling for performing a QSDC protocol using time bins and polarization according to an embodiment of the present disclosure. Referring to FIG. 24, a transmitting node (2410) and a receiving node (2420) can generate a quantum state using time bins and polarization, and can perform a QSDC protocol based on the generated quantum state. To perform FIG. 24, the transmitting node (2410) and the receiving node (2420) may first perform an initial access procedure (e.g., a random access procedure). In FIG. 24, the receiving node (2420) generates an initial quantum state that functions as a secret key for QKD in the QSDC protocol, measures the encoded quantum state, verifies the security of the reverse quantum channel, and restores message information. The transmitting node (2410) verifies the security of the forward quantum channel, generates a classical message to be transmitted, and generates an encoded quantum state.

[0250] In step S2401, the receiving node (2420) generates an initial quantum state and stores information related to the initial quantum state. The information related to the initial quantum state may include the basis and state of the initial quantum state. The information related to the initial quantum state may be used for decoding and QBER estimation.

[0251] In step S2403, the receiving node (2420) transmits initial quantum states to the transmitting node (2410). The initial quantum states can be generated from a Z basis or an X basis and can consist of one of the higher-dimensional quantum states. The higher-dimensional quantum states can be generated based on the time bins assigned to the quantum states and the applied polarization or phase. The initial quantum states can be transmitted through a forward quantum channel.

[0252] In step S2405, the transmitting node (2410) stores the received initial quantum states. Some of the received initial quantum states can be used for QBER estimation, and the remaining received initial quantum states are stored in quantum memory and can be used for the generation of a second signal.

[0253] In step S2407, the transmitting node (2410) receives information related to the initial quantum states from the receiving node (2420). The information related to the initial quantum states transmitted to the transmitting node (2410) may include quantum state information of the initial quantum states to be used for QBER estimation.

[0254] In step S2409, the transmitting node (2410) estimates the QBER and determines whether an eavesdropper is present. The QBER can be measured by comparing the quantum states measured by the transmitting node (2410) with the quantum states generated by the receiving node (2420). The transmitting node (2410) determines whether an eavesdropper is present based on the QBER and may declare the cessation of quantum communication. For example, if the QBER exceeds a preset threshold, quantum communication may be stopped. Although the present disclosure describes the QBER as being estimated by the transmitting node (2410) for convenience of explanation, the QBER estimation may be performed not only by the transmitting node (2410) but also by the receiving node (2420) or other control nodes. For example, the control node may estimate the QBER by receiving the measurement results from the transmitting node (2410) and receiving information related to the initial quantum states from the receiving node (2420). As another example, a receiving node (2420) may receive a measurement result from a transmitting node (2410) and estimate a QBER based on the measurement result and information related to the quantum states it stores. To this end, the locations, bases, and measurement values ​​of the quantum states may be exchanged between the nodes.

[0255] In step S2411, the transmitting node (2410) generates encoded quantum states using initial quantum states. The transmitting node (2410) can generate encoded quantum states using initial quantum states stored in quantum memory. To do this, the transmitting node (2410) generates a whole codeword for data transmission and can divide the whole codeword so that it can be mapped to N-dimensional quantum states. That is, the codeword can be divided into transmittable sizes (e.g., ┗log2 N┛) before being mapped to N-dimensional quantum states. The transmitting node (2410) can map the divided codeword to delay time information and polarization or phase information. Depending on the message bit information, the initial quantum state can first be encoded based on polarization or phase information and then transmitted via a path determined based on delay time information to be converted into an encoded quantum state. As a result of encoding, the time bin of the photon included in the initial quantum state can be shifted, and the polarization or phase of the photon can be changed. The codeword may include values ​​to which error correction codes have been applied to the transmitted message bits.

[0256] In step S2413, the transmitting node (2410) transmits encoded quantum states to the receiving node (2420). The encoded quantum states can be transmitted through a reverse quantum channel.

[0257] In step S2415, the receiving node (2420) measures the encoded quantum states. To measure the encoded quantum states, information regarding the location of the quantum states, information regarding the basis of the quantum states, and information regarding the measurement value may be shared between the receiving node (2420) and the transmitting node (2410).

[0258] In step S2417, the receiving node (2420) determines the QBER estimation and the presence of an eavesdropper. At this time, some of the encoded quantum states may be used for QBER estimation. Additionally, some of the quantum states of the X basis and Z basis may also be used for QBER estimation.

[0259] In step S2419, the receiving node (2420) performs data decoding. Here, an error correction code may be utilized for data decoding. Data decoding may be performed based on the measured quantum state and the decoding table. The codewords obtained through decoding can be converted into transmitted message bits through the correction of the error correction code.

[0260] In step S2421, the receiving node (2420) recovers the message. The receiving node (2420) recovers the message transmitted by the transmitting node (2410) using the transmitted message bits.

[0261] When performing a QSDC protocol using multidimensional quantum states by using the methods described above in the present disclosure, the time required to generate a single quantum state can be reduced. In other words, the effect of increasing the transmission rate can occur. For example, when performing a QSDC protocol using four-dimensional quantum states, as shown in FIG. 17, it is composed of four time bins, the first two time bins are used for generating the initial quantum state, the third time bin is used for generating the encoding state, and the remaining fourth time bin can be used to secure a minimum time interval for detecting consecutive quantum states. This minimum time interval can be referred to as dead time and is a time interval corresponding to two time bins. That is, during the measurement process, if a subsequent quantum state is input after the preceding quantum state among consecutive quantum states has been measured and before the detector is refreshed, it may not be detected. To prevent such information loss, a fourth time bin is utilized for dead time. In the present disclosure, since encoded quantum states are detected only in the first to third time bins, adding one time bin allows for dead time between consecutive quantum states. Therefore, the technique proposed in the present disclosure requires a total time interval for generating a single quantum state that is twice the dead time of the detector.

[0262] In contrast, in the conventional 4D single-photon-based QSDC technique, a single 4D quantum state can be transmitted through 10 time bins, as in the case where N=4 in FIG. 15a and 15b. Similar to the technique proposed in this disclosure, the interval corresponding to 4 time bins corresponds to the dead time of the SPD. Specifically, the first 4 time bins are used for the generation of the initial quantum state, the 5th to 7th time bins are used for the generation of the encoded quantum state, and the 8th to 10th time bins are used to secure the dead time. Therefore, the conventional technique requires a total time interval of 2.5 times the detector's dead time for the generation of a single quantum state.

[0263] The total number of time resources and time bins used in the QSDC technique of the present invention and the existing QSDC technique can be expressed as shown in [Table 8].

[0264] 4-dimensional quantum state standard Existing QSDC technique QSDC technique proposed in this disclosure Time interval required to generate a single quantum state 2.5 × (dead time) 2 × (dead time) Time required to generate a single quantum state Number of bins 104

[0265] Referring to [Table 8], it can be seen that the QSDC technique proposed in this disclosure improves the time interval required to generate a quantum state by 20% and reduces the usage of required time bins by 60% compared to the existing QSDC. Since the QSDC technique proposed in this disclosure can reduce the time required to generate single quantum state information by 20% compared to the existing technique, the transmission rate can be improved by the proportion of the reduction in quantum state generation time. In addition, since the QSDC technique proposed in this disclosure can configure time bins with longer time intervals than the existing QSDC technique, it can have an advantage in overcoming hardware constraints that occur during the optical signal generation and phase modulation processes when configuring a quantum communication system.

[0266] In conventional single-photon-based 4D QSDC protocols, a time interval 2.5 times the dead time of the SPD is divided into 10 time bins to generate single quantum information. Therefore, the time interval allocated to a single time bin can have a length of 0.25 times the dead time. In conventional QSDC protocols, quantum information is generated by positioning a single photon at a specific time bin location or by modulating phase information. In existing techniques, since the time interval occupied by a single time bin is only 0.25 times the dead time, if the repetition rate of the optical signal generated by the laser equipment (e.g., laser diode, laser source) is low or the pulse width of each optical pulse is wide, it can affect signals in surrounding time bins, making it difficult to smoothly generate quantum states. Therefore, high-performance laser sources must be used. Additionally, since there may be limitations to the operating speed of phase modulation, it may be difficult to smoothly generate phase information in consecutive time bins when the intervals between time bins are narrow.

[0267] However, the QSDC protocol proposed in this disclosure divides the time into four time bins corresponding to twice the dead time of the SPD for the generation of single quantum information. Therefore, the time interval allocated to one time bin is 0.5 times the dead time, which is twice as long as that of the existing method. Consequently, compared to the existing method, the requirements regarding the pulse width or repetition rate of the laser equipment during the optical signal generation process can be relaxed under the same conditions. Furthermore, regarding phase modulation, the existing method requires changing the phase in four consecutive short time intervals when configuring a 4-dimensional phase state. On the other hand, the method proposed in this disclosure uses a phase modulation method where the phase is changed only in the first time bin, thereby allowing it to be used for the transmission of high-dimensional information even if the operation speed of the phase modulation is slow.

[0268] Although the specific time intervals described in this disclosure are referred to as time bins, time bins may be referred to as time intervals, time slots, slots, time frames, frames, subframes, time windows, time blocks, time units, sampling intervals, or other terms having an equivalent technical meaning.

[0269] Hereinafter, examples of wireless device applications to which various embodiments of the present disclosure are applied will be described.

[0270] FIG. 25 illustrates an example of a wireless device applicable to the present disclosure. The wireless device may be implemented in various forms depending on the use—example / service (see FIG. 1).

[0271] Referring to FIG. 25, the wireless device (200) corresponds to the wireless device (200) of FIG. 2 and may be composed of various elements, components, units / parts, and / or modules. For example, the wireless device (200) may include a communication unit (210), a control unit (220), a memory unit (230), and additional elements (240). The communication unit may include a communication circuit (212) and transceiver(s) (214). For example, the communication circuit (212) may include one or more processors (202) and / or one or more memories (204) of FIG. 2. For example, the transceiver(s) (214) may include one or more transceivers (206) and / or one or more antennas (208) of FIG. 2. The control unit (220) is electrically connected to the communication unit (210), the memory unit (230), and additional elements (240) and controls the overall operation of the wireless device. For example, the control unit (220) can control the electrical / mechanical operation of the wireless device based on a program / code / command / information stored in the memory unit (230). Additionally, the control unit (220) can transmit information stored in the memory unit (230) to an external entity (e.g., another communication device) via a wireless / wired interface through the communication unit (210), or store information received from an external entity (e.g., another communication device) via a wireless / wired interface through the communication unit (210) in the memory unit (230).

[0272] The additional element (240) may be configured in various ways depending on the type of wireless device. For example, the additional element (240) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 1, 100a), a vehicle (Fig. 1, 100b-1, 100b-2), an XR device (Fig. 1, 100c), a portable device (Fig. 1, 100d), a home appliance (Fig. 1, 100e), an IoT device (Fig. 1, 100f), a digital broadcasting terminal, a holographic device, a public safety device, an MTC device, a medical device, a fintech device (or financial device), a security device, a climate / environment device, an AI server / device (Fig. 1, 400), a base station (Fig. 1, 200), a network node, etc. Depending on the use—e.g., service—the wireless device may be movable or used in a fixed location.

[0273] In FIG. 25, various elements, components, units / parts, and / or modules within the wireless device (200) may be entirely interconnected via a wired interface, or at least partially connected via a communication unit (210). For example, within the wireless device (200), the control unit (220) and the communication unit (210) may be connected via a wire, and the control unit (220) and the first unit (e.g., 230, 240) may be connected wirelessly via the communication unit (210). Additionally, each element, component, unit / part, and / or module within the wireless device (200) may include one or more additional elements. For example, the control unit (220) may be composed of one or more sets of processors. For example, the control unit (220) may be composed of a set of a communication control processor, an application processor, an Electronic Control Unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory and / or a combination thereof.

[0274] Hereinafter, an implementation example of FIG. 25 will be described in more detail with reference to the drawings.

[0275] FIG. 26 illustrates an example of a portable device applicable to the present disclosure. The portable device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch, smart glasses), or a portable computer (e.g., a laptop). The portable device may be referred to as a Mobile Station (MS), a User Terminal (UT), a Mobile Subscriber Station (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or a Wireless Terminal (WT).

[0276] Referring to FIG. 26, the portable device (200) may include an antenna unit (208), a communication unit (210), a control unit (220), a memory unit (230), a power supply unit (240a), an interface unit (240b), and an input / output unit (240c). The antenna unit (208) may be configured as part of the communication unit (210). Blocks 210 to 230 / 240a to 240c of FIG. 26 correspond to blocks 210 to 230 / 240 of FIG. 25, respectively.

[0277] The communication unit (210) can transmit and receive signals (e.g., data, control signals, etc.) with other wireless devices and base stations. The control unit (220) can control the components of the portable device (200) to perform various operations. The control unit (220) may include an AP (Application Processor). The memory unit (230) can store data / parameters / programs / code / commands required for the operation of the portable device (200). Additionally, the memory unit (230) can store input / output data / information, etc. The power supply unit (240a) supplies power to the portable device (200) and may include wired / wireless charging circuits, batteries, etc. The interface unit (240b) can support the connection between the portable device (200) and other external devices. The interface unit (240b) may include various ports (e.g., audio input / output ports, video input / output ports) for connection with external devices. The input / output unit (240c) can receive or output video information / signals, audio information / signals, data, and / or information input by a user. The input / output unit (240c) may include a camera, a microphone, a user input unit, a display unit (240d), a speaker and / or a haptic module, etc.

[0278] For example, in the case of data communication, the input / output unit (240c) acquires information / signals (e.g., touch, text, voice, image, video) input by the user, and the acquired information / signals can be stored in the memory unit (230). The communication unit (210) converts the information / signals stored in the memory into wireless signals and can directly transmit the converted wireless signals to another wireless device or to a base station. Additionally, the communication unit (210) can receive wireless signals from another wireless device or base station and then restore the received wireless signals to their original information / signals. The restored information / signals are stored in the memory unit (230) and then can be output in various forms (e.g., text, voice, image, video, haptic) through the input / output unit (240c).

[0279] FIG. 27 illustrates an example of a vehicle or autonomous vehicle applicable to the present disclosure. The vehicle or autonomous vehicle may be implemented as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, etc.

[0280] Referring to FIG. 27, a vehicle or autonomous vehicle (200-1) may include an antenna unit (208-1), a communication unit (210-1), a control unit (220-1), a driving unit (240a-1), a power supply unit (240b-1), a sensor unit (240c-1), and an autonomous driving unit (240d-1). The antenna unit (208-1) may be configured as part of the communication unit (210-1). Blocks 210-1 / 230-1 / 240a-1 to 240d-1 of FIG. 27 correspond to blocks 210 / 230 / 240 of FIG. 25, respectively.

[0281] The communication unit (210-1) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, roadside base stations (Road Side Unit), etc.), and servers. The control unit (220-1) can perform various operations by controlling elements of the vehicle or autonomous vehicle (200-1). The control unit (220-1) may include an Electronic Control Unit (ECU). The driving unit (240a-1) can drive the vehicle or autonomous vehicle (200-1) on the ground. The driving unit (240a-1) may include an engine, motor, power train, wheels, brakes, steering device, etc. The power supply unit (240b-1) supplies power to the vehicle or autonomous vehicle (200-1) and may include wired / wireless charging circuits, batteries, etc. The sensor unit (240c-1) can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit (240c-1) may include an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit (240d-1) may implement technologies such as maintaining the driving lane, technologies for automatically adjusting speed such as adaptive cruise control, technologies for automatically driving along a predetermined path, and technologies for automatically setting a path and driving when a destination is set.

[0282] For example, the communication unit (210-1) can receive map data, traffic information data, etc. from an external server. The autonomous driving unit (240d-1) can generate an autonomous driving path and a driving plan based on the acquired data. The control unit (220-1) can control the drive unit (240a-1) so that the vehicle or the autonomous vehicle (200-1) moves along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (210-1) can acquire the latest traffic information data from an external server non-periodically and can acquire surrounding traffic information data from surrounding vehicles. Additionally, during autonomous driving, the sensor unit (240c-1) can acquire vehicle status and surrounding environment information. The autonomous driving unit (240d-1) can update the autonomous driving path and the driving plan based on the newly acquired data / information. The communication unit (210-1) can transmit information regarding the vehicle location, autonomous driving path, driving plan, etc. to an external server. An external server can predict traffic information data in advance using AI technology, etc., based on information collected from vehicles or autonomous vehicles, and can provide the predicted traffic information data to vehicles or autonomous vehicles. If the device (220-2) is an autonomous vehicle, it can perform the same procedure as the vehicle or autonomous vehicle (200-1). In addition, if the device (220-2) is a base station or a roadside base station, the device (220-2) can transmit data and control signals to the vehicle or autonomous vehicle (200-1) through the communication unit (210-2).

[0283] FIG. 28 illustrates an example of a vehicle applicable to the present disclosure. The vehicle may be implemented as a means of transport, a train, an aircraft, a ship, etc. Referring to FIG. 28, the vehicle (200) may include a communication unit (210), a control unit (220), a memory unit (230), an input / output unit (240a), and a position measurement unit (240b). Here, blocks 210 to 230 / 240a to 240b correspond to blocks 210 to 230 / 240 of FIG. 25, respectively.

[0284] The communication unit (210) can transmit and receive signals (e.g., data, control signals, etc.) with other vehicles or external devices such as base stations. The control unit (220) can control the components of the vehicle (200) to perform various operations. The memory unit (230) can store data / parameters / programs / codes / commands that support various functions of the vehicle (100). The input / output unit (240a) can output AR / VR objects based on information within the memory unit (230). The input / output unit (240a) may include a HUD. The position measurement unit (240b) can acquire position information of the vehicle (200). The position information may include absolute position information of the vehicle (200), position information within the driving line, acceleration information, position information relative to surrounding vehicles, etc. The position measurement unit (240b) may include GPS and various sensors.

[0285] For example, the communication unit (210) of the vehicle (200) can receive map information, traffic information, etc. from an external server and store it in the memory unit (230). The location measurement unit (240b) can acquire vehicle location information through GPS and various sensors and store it in the memory unit (230). The control unit (220) creates a virtual object based on map information, traffic information, and vehicle location information, etc., and the input / output unit (240a) can display the created virtual object on the glass window inside the vehicle (240a-1, 240a-2). In addition, the control unit (220) can determine whether the vehicle (200) is operating normally within the driving line based on the vehicle location information. If the vehicle (200) deviates abnormally from the driving line, the control unit (220) can display a warning on the glass window inside the vehicle through the input / output unit (240a). Additionally, the control unit (220) can broadcast a warning message regarding a driving abnormality to surrounding vehicles through the communication unit (210). Depending on the situation, the control unit (220) can transmit the vehicle's location information and information regarding the driving / vehicle abnormality to relevant authorities through the communication unit (210).

[0286] FIG. 29 illustrates an example of an XR device applicable to the present disclosure. The XR device may be implemented as an HMD, a Head-Up Display (HUD) equipped in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc.

[0287] Referring to FIG. 29, the XR device (200a) may include a communication unit (210), a control unit (220), a memory unit (230), an input / output unit (240a), a sensor unit (240b), and a power supply unit (240c). Here, blocks 210 to 230 / 240a to 240c of FIG. 29 correspond to blocks 210 to 230 / 240 of FIG. 25, respectively.

[0288] The communication unit (210) can transmit and receive signals (e.g., media data, control signals, etc.) with external devices such as other wireless devices, mobile devices, or media servers. The media data may include video, images, sound, etc. The control unit (220) can perform various operations by controlling the components of the XR device (200a). For example, the control unit (220) may be configured to control and / or perform procedures such as video / image acquisition, (video / image) encoding, metadata generation, and processing. The memory unit (230) may store data / parameters / programs / code / commands required for driving the XR device (200a) or creating an XR object. The input / output unit (240a) acquires control information, data, etc. from the outside and can output the created XR object. The input / output unit (240a) may include a camera, microphone, user input unit, display unit, speaker and / or haptic module, etc. The sensor unit (240b) can obtain XR device status, surrounding environment information, user information, etc. The sensor unit (240b) may include a proximity sensor, an illuminance sensor, an accelerometer, a magnetic sensor, a gyroscope, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone and / or radar, etc. The power supply unit (240c) supplies power to the XR device (200a) and may include a wired / wireless charging circuit, a battery, etc.

[0289] For example, the memory unit (230) of the XR device (200a) may contain information (e.g., data, etc.) necessary for creating an XR object (e.g., AR / VR / MR object). The input / output unit (240a) may receive a command to operate the XR device (200a) from the user, and the control unit (220) may operate the XR device (200a) according to the user's operation command. For example, if the user intends to watch movies, news, etc. through the XR device (200a), the control unit (220) may transmit content request information to another device (e.g., mobile device (200b)) or a media server through the communication unit (230). The communication unit (230) may download / stream content such as movies, news, etc. from another device (e.g., mobile device (200b)) or a media server to the memory unit (230). The control unit (220) controls and / or performs procedures such as video / image acquisition, (video / image) encoding, and metadata generation / processing for the content, and can generate / output an XR object based on information about the surrounding space or real object acquired through the input / output unit (240a) / sensor unit (240b).

[0290] Additionally, the XR device (200a) is wirelessly connected to the mobile device (200b) through the communication unit (210), and the operation of the XR device (200a) can be controlled by the mobile device (200b). For example, the mobile device (200b) can act as a controller for the XR device (200a). To this end, the XR device (200a) can acquire three-dimensional position information of the mobile device (200b), and then generate and output an XR object corresponding to the mobile device (200b).

[0291] FIG. 30 illustrates an example of a robot applicable to the present disclosure. Robots may be classified into industrial, medical, domestic, military, etc., depending on the purpose or field of use.

[0292] Referring to FIG. 30, the robot (200) may include a communication unit (210), a control unit (220), a memory unit (230), an input / output unit (240a), a sensor unit (240b), and a driving unit (240c). Here, blocks 210 to 230 / 240a to 240c of FIG. 30 correspond to blocks 210 to 230 / 240 of FIG. 25, respectively.

[0293] The communication unit (210) can transmit and receive signals (e.g., driving information, control signals, etc.) with external devices such as other wireless devices, other robots, or control servers. The control unit (220) can control the components of the robot (200) to perform various operations. The memory unit (230) can store data / parameters / programs / codes / commands that support various functions of the robot (200). The input / output unit (240a) can acquire information from outside the robot (200) and output information to outside the robot (200). The input / output unit (240a) may include a camera, microphone, user input unit, display unit, speaker and / or haptic module, etc. The sensor unit (240b) can obtain internal information of the robot (200), surrounding environment information, user information, etc. The sensor unit (240b) may include a proximity sensor, an illuminance sensor, an accelerometer, a magnetic sensor, a gyroscope, an inertial sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, a radar, etc. The driving unit (240c) may perform various physical movements, such as moving robot joints. Additionally, the driving unit (240c) may enable the robot (200) to travel on the ground or fly in the air. The driving unit (240c) may include an actuator, a motor, a wheel, a brake, a propeller, etc.

[0294] FIG. 31 illustrates an example of an AI device applicable to the present disclosure.

[0295] AI devices can be implemented as stationary devices or mobile devices, such as TVs, projectors, smartphones, PCs, laptops, digital broadcasting terminals, tablet PCs, wearable devices, set-top boxes (STBs), radios, washing machines, refrigerators, digital signage, robots, vehicles, etc.

[0296] Referring to FIG. 31, the AI ​​device (200) may include a communication unit (210), a control unit (220), a memory unit (230), an input / output unit (240a / 240b), a learning processor unit (240c), and a sensor unit (240d). Blocks 210 to 230 / 240a to 240d of FIG. 31 correspond to blocks 210 to 230 / 140 of FIG. 25, respectively.

[0297] The communication unit (210) can transmit and receive wired and wireless signals (e.g., sensor information, user input, learning model, control signal, etc.) with external devices such as other AI devices (e.g., 100a to 100f, 120 in FIG. 1) or AI servers (e.g., 100g in FIG. 1) using wired and wireless communication technology. To do this, the communication unit (210) can transmit information within the memory unit (230) to an external device or transmit signals received from an external device to the memory unit (230).

[0298] The control unit (220) can determine at least one executable operation of the AI ​​device (200) based on information determined or generated using a data analysis algorithm or a machine learning algorithm. The control unit (220) can perform the determined operation by controlling the components of the AI ​​device (200). For example, the control unit (220) can request, search, receive, or utilize data from the learning processor unit (240c) or the memory unit (230), and can control the components of the AI ​​device (200) to execute a predicted operation or an operation determined to be desirable among at least one executable operation. Additionally, the control unit (220) can collect historical information, including the operation content of the AI ​​device (200) or user feedback regarding the operation, and store it in the memory unit (230) or the learning processor unit (240c), or transmit it to an external device such as an AI server (Fig. 1, 100g). The collected historical information can be used to update the learning model.

[0299] The memory unit (230) can store data that supports various functions of the AI ​​device (200). For example, the memory unit (230) can store data obtained from the input unit (240a), data obtained from the communication unit (210), output data from the learning processor unit (240c), and data obtained from the sensing unit (140). Additionally, the memory unit (230) can store control information and / or software code required for the operation / execution of the control unit (220).

[0300] The input unit (240a) can acquire various types of data from outside the AI ​​device (200). For example, the input unit (220) can acquire training data for model training and input data to which the training model is applied. The input unit (240a) may include a camera, a microphone and / or a user input unit, etc. The output unit (240b) can generate output related to visual, auditory, or tactile senses, etc. The output unit (240b) may include a display unit, a speaker and / or a haptic module, etc. The sensing unit (140d) can obtain at least one of internal information of the AI ​​device (200), surrounding environment information of the AI ​​device (200), and user information using various sensors. The sensing unit (140d) may include a proximity sensor, an illuminance sensor, an accelerometer, a magnetic sensor, a gyroscope, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone and / or radar, etc.

[0301] The learning processor unit (240c) can train a model composed of an artificial neural network using training data. The learning processor unit (240c) can perform AI processing together with the learning processor unit of the AI ​​server (Fig. 1, 100g). The learning processor unit (240c) can process information received from an external device through the communication unit (210) and / or information stored in the memory unit (230). Additionally, the output value of the learning processor unit (240c) can be transmitted to an external device through the communication unit (210) and / or stored in the memory unit (230).

[0302] The proposed methods described above may be implemented independently, but they may also be implemented in the form of a combination (or merger) of some of the proposed methods. Rules may be defined so that the base station informs the terminal of the application status of the proposed methods (or information regarding the rules of the proposed methods) through a predefined signal (e.g., a physical layer signal or an upper layer signal).

[0303] The present disclosure may be embodied in other specific forms without departing from the technical ideas and essential features described herein. Accordingly, the above detailed description should not be interpreted restrictively in all respects and should be considered illustrative. The scope of the present disclosure shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure. Furthermore, embodiments may be constructed by combining claims that are not explicitly related in the claims, or new claims may be included by amendments made after filing.

[0304] One embodiment can be applied to various wireless access systems. Examples of various wireless access systems include the 3GPP (3rd Generation Partnership Project) or 3GPP2 system.

[0305] One embodiment can be applied not only to the various wireless access systems mentioned above, but also to all technical fields utilizing the various wireless access systems. Furthermore, the proposed method can be applied to mmWave and THz communication systems utilizing the ultra-high frequency band.

[0306] Additionally, some embodiments may be applied to various applications such as autonomous vehicles and drones.

Claims

1. Regarding the method, Step of acquiring system information; A step of performing a random access procedure based on the above system information; Step of generating a first signal; A step of transmitting the above first signal to a second device; A step of receiving a second signal, which is encoded using the first signal from the second device; and The method includes the step of performing decoding of the second signal, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and A method in which the above initial quantum state is generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization or phase applied to said at least one time bin.

2. In Paragraph 1, The step of storing information related to the above initial quantum state is further included, The decoding of the second signal is performed based on the measurement result of the second signal and information related to the initial quantum state.

3. In Paragraph 1, The above initial quantum state is determined as one of the four quantum states of the first basis and the four quantum states of the second basis, and A method in which the above initial quantum state is determined based on a single photon existing in the first time bin and the second time bin among a successive first time bin, second time bin, third time bin and fourth time bin.

4. In Paragraph 3, The four quantum states of the first basis above include a first state, a second state, a third state, and a fourth state, and When the above initial quantum state is the above first state, the single photon is assigned to the above second time bin, and horizontal polarization is applied to the above second time bin, and If the above initial quantum state is the above second state, the single photon is assigned to the above second time bin, and vertical polarization is applied to the above second time bin, and If the above initial quantum state is the above third state, the single photon is assigned to the above first time bin, horizontal polarization is applied to the above second time bin, and A method in which, when the above initial quantum state is the above fourth state, the single photon is assigned to the above first time bin and vertical polarization is applied to the above second time bin.

5. In Paragraph 4, The second signal above includes an encoded quantum state generated using the initial quantum state, and A method in which the above-mentioned encoded quantum state is generated based on the degree of delay of the transmission path after applying polarization or phase according to the basis of the above-mentioned initial quantum state.

6. In Paragraph 3, The four quantum states of the second basis above include the fifth state, the sixth state, the seventh state, and the eighth state, and When the above initial quantum state is the above fifth state, the single photon is assigned to the above first time bin and the above second time bin with equal probability, configured so that the phase difference applied to the above first time bin and the above second time bin is zero, polarization of -45° is applied to the above first time bin and polarization of 45° is applied to the above second time bin, and When the above initial quantum state is the above 6th state, the single photon is assigned to the above 1st time bin and the above 2nd time bin with equal probability, and the phase difference applied to the above 1st time bin and the above 2nd time bin is configured to be π, and polarization of -45° is applied to the above 1st time bin and polarization of 45° is applied to the above 2nd time bin, and When the above initial quantum state is the above seventh state, the single photon is assigned to the first time bin and the second time bin with equal probability, configured so that the phase difference applied to the first time bin and the second time bin is zero, polarization of 45° is applied to the first time bin, and polarization of -45° is applied to the second time bin, and A method in which, when the above initial quantum state is the above eighth state, the single photon is assigned to the above first time bin and the above second time bin with equal probability, configured such that the phase difference applied to the above first time bin and the above second time bin is π, and polarization of 45° is applied to the above first time bin and polarization of -45° is applied to the above second time bin.

7. In Paragraph 1, The step of receiving the second signal is, A step of determining a detection path corresponding to the second signal based on the basis of the initial quantum state; and A method comprising the step of controlling an optical switch (OSW) based on the above-determined detection path.

8. In Paragraph 1, The second signal is detected using devices related to the first basis, and The above-mentioned devices related to the first base include a PBS (polarized beam splitter) and two SPDs (single photon detectors).

9. In Paragraph 8, The above decoding is a method performed based on the initial quantum state, the time bin at which the second signal is detected, and the location of the SPD at which the second signal is detected.

10. In Paragraph 1, The second signal is detected using devices related to the second basis, and The above-mentioned devices related to the second basis are detected using two PCs (polarization controllers), two PBSs (polarized beam splitters), two delay lines, two BSs (beam splitters), and four SPDs (single photon detectors).

11. In Paragraph 10, The method further includes the step of determining a QBER (quantum bit error rate) based on the SPD among the four SPDs where the second signal is detected and the initial quantum state, wherein A method further comprising a method for determining the presence of an eavesdropper in a reverse quantum channel based on the above QBER.

12. In Paragraph 1, The plurality of time bins to which the first signal is assigned include at least one time bin to which the single photon is assigned, a time bin where encoding is performed, and a guard time bin. A method in which the total time interval corresponding to the above plurality of time bins is set to twice the dead time of the detector.

13. Regarding the method, Step of transmitting system information; A step of performing a random access procedure based on the above system information; A step of receiving a first signal from a first device; A step of generating a second signal by performing encoding using the first signal; and The method includes the step of transmitting the second signal to the first device, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and A method in which the above initial quantum state is generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization or phase applied to said at least one time bin.

14. In Paragraph 13, A step of estimating the quantum bit error rate (QBER) based on the first signal; and A method further comprising the step of determining the presence or absence of an eavesdropper in a forward quantum channel based on the above QBER.

15. In Paragraph 13, If the initial quantum state is generated based on the first basis, the second signal includes an encoded quantum state generated by performing the encoding based on time delay information and polarization information using the initial quantum state, and A method in which, when the initial quantum state is generated based on the second basis, the second signal includes an encoded quantum state generated by performing the encoding based on time delay information and phase information on the initial quantum state.

16. In the first device, Transmitter / receiver; and It includes a processor coupled to the above-mentioned transmitter and receiver, The above processor is, Acquire system information, and Based on the above system information, a random access procedure is performed, and Generate a first signal, and Transmitting the above first signal to the second device, A second signal is received from the second device, which is encoded using the first signal, and Configured to perform decoding of the above second signal, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and The above initial quantum state is a first device generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

17. In the second device, Transmitter / receiver; and It includes a processor connected to the above-mentioned transmitter and receiver, The above processor is, Transmit system information, and Based on the above system information, a random access procedure is performed, and Receive a first signal from a first device, and By performing encoding using the first signal above, a second signal is generated, and Control the first device to transmit the second signal, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and The above initial quantum state is a second device generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

18. In the terminal, At least one processor; It includes at least one computer memory connected to the at least one processor and storing instructions that direct operations as they are executed by the at least one processor, The above operations are, Step of acquiring system information; A step of performing a random access procedure based on the above system information; Step of generating a first signal; A step of transmitting the above first signal to a second device; A step of receiving a second signal, which is encoded using the first signal from the second device; and The method includes the step of performing decoding of the second signal, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and The above initial quantum state is a terminal generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

19. In a non-transitory computer-readable medium storing at least one instruction, It includes at least one instruction executable by a processor, The above at least one instruction is, the device, Acquire system information, and Based on the above system information, a random access procedure is performed, and Generate a first signal, and Transmitting the above first signal to the second device, A second signal is received from the second device, which is encoded using the first signal, and Configured to perform decoding of the above second signal, The first signal above includes an initial quantum state generated based on a first basis or a second basis, and The above initial quantum state is a computer-readable medium generated based on at least one time bin to which a single photon is assigned among a plurality of time bins to which the first signal is assigned, and polarization and phase applied to the at least one time bin.

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