Method and apparatus for controlling access based on common resources in a communication system

Abstract

A method and device for controlling access based on public resources in a communication system are disclosed. The operation method of a terminal according to an embodiment of the present invention comprises the following steps: receiving configuration information of public resources from a first base station among multiple base stations; receiving public information from the first base station via the public resources indicated by the configuration information; and performing a random access procedure with a second base station among the multiple base stations by using the public information. Therefore, the performance of the communication system can be improved.

Description

[0001] This application is a divisional application of the Chinese invention patent application with international application number PCT / KR2017 / 010146 filed on September 15, 2017, application number 201780052861.6 entering the Chinese national phase on February 27, 2019, and invention name “Method and device for controlling access based on public resources in a communication system”. Technical Field

[0002] The present invention relates to access control technology in a communication system, and more particularly to a technology for controlling access to minimize unnecessary system information acquisition processes. Background Art

[0003] A communication system (hereinafter, 'integrated communication system') using a higher frequency band (e.g., 6 GHz or higher) than a frequency band (e.g., a frequency band below 6 GHz) of a communication system based on long term evolution (LTE) (or a communication system based on LTE-A) is being considered for handling the surge in wireless data. The reception performance of the signal may deteriorate due to the path loss of radio waves and the reflection of radio waves in such a high frequency band (e.g., 6 GHz or higher), and in order to solve this problem, a small base station (small base station) that supports a smaller cell coverage range than a macro base station (macro base station) can be introduced into the integrated communication system. In the integrated communication system, the small base station can be connected to the core network using a wired backhaul link.

[0004] At the same time, the integrated communication system may include: a small base station that performs all functions of the communication protocol (e.g., remote radio transmission and reception functions, baseband processing functions), multiple transmission reception points (TRPs) that perform remote radio transmission and reception functions among the functions of the communication protocol, a baseband unit (BBU) block that performs baseband processing functions among the functions of the communication protocol, etc. The TRP may be a remote radio head (RRH), a radio unit (RU), etc. The BBU block may include at least one BBU or at least one digital unit (DU). The BBU block may be referred to as a 'BBU pool', a 'centralized BBU', etc. One BBU block may be connected to multiple TRPs and perform baseband processing functions on signals received from multiple TRPs and signals to be sent to multiple TRPs.

[0005] In the above communication system, when there are multiple base stations, each of the multiple base stations may transmit system information. The terminal may perform an access procedure using the system information received from each of the multiple base stations. A portion of the system information may be common among the multiple base stations. However, even when there is common system information, the terminal performs a process of acquiring all system information of the base station for the access process, and thus the overhead caused by the process may increase. Summary of the invention

[0006]

Technical issues

[0007] In order to solve the above problems, the present invention is intended to provide a method and apparatus for controlling access in a communication system to minimize unnecessary system information acquisition processes.

[0008]

Technical solution

[0009] According to a first embodiment of the present invention for achieving the above-mentioned purpose, an operation method performed by a terminal in a communication system including multiple base stations may include: receiving configuration information of common resources from a first base station among the multiple base stations; receiving common information from the first base station via the common resources indicated by the configuration information; and performing a random access process with a second base station among the multiple base stations by using the common information, wherein the common resources and the common information are configured identically for the multiple base stations.

[0010] Here, the random access process may be performed without performing a process of acquiring the system information of the second base station.

[0011] Here, the random access procedure may be performed using the resources indicated by the common information.

[0012] Here, performing the random access process may include: sending a message requesting other system information of the second base station to the second base station; and receiving the other system information from the second base station, wherein the other system information is system information among all system information of the second base station except the system information included in the public information.

[0013] Here, the message may be a random access preamble, and the other system information may be acquired via a random access response.

[0014] Here, the common information may include at least one of system information, control information, physical channel information, reference signal information, and resource allocation information that are identically configured in the plurality of base stations.

[0015] Here, the common information may include a service area identifier indicating a service area (SA) to which the common information is applied, and the second base station may belong to the service area indicated by the SA identifier.

[0016] Here, common resources may be independently configured according to the type of resource allocation information included in the common information, and the resource allocation information may include at least one of resource allocation information for control channels, resource allocation information for random access procedures, resource allocation information for scheduling requests, and resource allocation information for downlink transmission requests.

[0017] According to a second embodiment of the present invention for achieving the above-mentioned purpose, an operation method of a first base station among multiple base stations included in a communication system may include: sending configuration information of common resources configured equally for the multiple base stations; sending common information configured equally for the multiple base stations via the common resources indicated by the configuration information; and performing a random access process with a terminal based on the common information.

[0018] Here, the random access procedure may be performed without performing a procedure of sending the system information of the first base station.

[0019] Here, the terminal may be in a state where a connection process with a second base station among the plurality of base stations has been completed.

[0020] Here, performing the random access process may include: receiving a message from a terminal requesting other system information of the first base station; and sending the other system information to the terminal in response to the message, wherein the other system information is system information among all system information of the first base station except the system information included in the public information.

[0021] Here, the common information may include at least one of system information, control information, physical channel information, reference signal information and resource allocation information configured identically in the multiple base stations, and a service area (SA) identifier indicating a service area to which the common information is applied.

[0022] Here, the common resources can be independently configured according to the type of resource allocation information included in the common information, and the resource allocation information may include at least one of resource allocation information for a control channel, resource allocation information for the random access process, resource allocation information for a scheduling request, and resource allocation information for a downlink transmission request.

[0023] According to a third embodiment of the present invention for achieving the above-mentioned purpose, a terminal in a communication system including multiple base stations may include: a processor and a memory storing at least one instruction executed by the processor, and the at least one instruction may be configured to: receive configuration information of common resources from a first base station among the multiple base stations; receive common information from the first base station via the common resources indicated by the configuration information; and perform a random access process with a second base station among the multiple base stations by using the common information, wherein the common resources and the common information are configured identically for the multiple base stations.

[0024] Here, the random access process may be performed without performing a process of acquiring the system information of the second base station.

[0025] Here, the at least one instruction can also be configured to: when executing the random access process, send a message to the second base station requesting other system information of the second base station; and receive the other system information from the second base station, wherein the other system information is system information among all system information of the second base station except the system information included in the public information.

[0026] Here, the common information may include at least one of system information, control information, physical channel information, reference signal information, and resource allocation information that are identically configured in the plurality of base stations.

[0027] Here, the common information may include a service area (SA) identifier indicating a service area to which the common information is applied, and the second base station may belong to the service area indicated by the SA identifier.

[0028] Here, common resources may be independently configured according to the type of resource allocation information included in the common information, and the resource allocation information may include at least one of resource allocation information for control channels, resource allocation information for random access procedures, resource allocation information for scheduling requests, and resource allocation information for downlink transmission requests.

[0029]

Beneficial Effects

[0030] According to the present invention, when the system information (e.g., public information) of the first base station is acquired, the terminal can perform an access process with the second base station by using the system information of the first base station without performing a process of acquiring the system information of the second base station. In addition, the terminal can receive minimum system information from the base station, can send a message to the base station requesting transmission of other system information when system information other than the minimum system information (e.g., additional system information) is required, and can receive the other system information from the base station. Therefore, the process of acquiring unnecessary system information can be minimized, and the performance of the communication system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a conceptual diagram showing a first embodiment of a communication system;

[0032] Figure 2 is a block diagram showing a first embodiment of a communication node constituting a communication system;

[0033] Figure 3 is a conceptual diagram showing a second embodiment of a communication system;

[0034] Figure 4 is a conceptual diagram showing a first embodiment of an integrated communication system;

[0035] Figure 5 is a conceptual diagram showing a second embodiment of an integrated communication system;

[0036] Figure 6 is a conceptual diagram showing a third embodiment of a communication system;

[0037] Figure 7 is a conceptual diagram showing a first embodiment of a common resource in a communication system;

[0038] Figure 8 is a conceptual diagram illustrating a second embodiment of a common resource in a communication system;

[0039] Fig. 9 is a sequence diagram showing a first embodiment of a public information acquisition process in a communication system;

[0040] Fig.10 is a sequence diagram illustrating a first embodiment of a beam pairing process in a communication system;

[0041] Fig.11 is a conceptual diagram showing an operation state of a terminal in a communication system;

[0042] Fig.12 is a sequence diagram showing a first embodiment of a downlink transmission request process in a communication system;

[0043] Fig.13 is a sequence diagram showing a first embodiment of a random access procedure in a communication system;

[0044] Fig.14 is a timing diagram showing a first embodiment of a method for transmitting a synchronization signal in a communication system; and

[0045] Fig.15 is a conceptual diagram showing a mapping relationship between resources in a communication system. DETAILED DESCRIPTION

[0046] Although the present invention is susceptible to various modifications and alternative forms, specific embodiments are shown and described in detail by way of example in the drawings. However, it should be understood that this description is not intended to limit the present invention to specific embodiments, but on the contrary, the present invention is to cover all modifications, equivalents and substitutes falling within the spirit and scope of the present invention.

[0047] Although the terms "first", "second", etc. may be used herein with respect to various elements, these elements should not be construed as being limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and a second element may be referred to as a first element. The term "and / or" includes any and all combinations of one or more of the related listed items.

[0048] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0049] The terms used in this article are only used for the purpose of describing specific embodiments, and are not intended to limit embodiments of the present invention. As used herein, the singular forms "a", "an", and "said" are also intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that when the terms "include", "comprise", "includes", and / or "comprising" are used in this article, the existence of the stated features, wholes, steps, operations, elements, parts, and / or combinations thereof is specified, but the existence or addition of one or more other features, wholes, steps, operations, elements, parts, and / or combinations thereof is not excluded.

[0050] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. It will be further understood that terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such in this article.

[0051] Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In order to facilitate a comprehensive understanding of the present invention, the same reference numerals refer to the same elements throughout the description of the drawings, and the description of the same components will not be repeated.

[0052] Hereinafter, a communication system to which an embodiment according to the present disclosure is applied will be described. However, the communication system to which an embodiment according to the present disclosure is applied is not limited to those to be described below. That is, the embodiment according to the present disclosure can be applied to various communication systems. Here, the term 'communication system' can be used with the same meaning as the term 'communication network'.

[0053] Figure 1 is a conceptual diagram showing a first embodiment of a communication system.

[0054] refer to Figure 1 , the communication system 100 may include a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6. In addition, the communication system 100 may include a core network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), a mobility management entity (MME), etc.).

[0055] The plurality of communication nodes may support fourth generation (4G) communications (e.g., long term evolution (LTE), advanced LTE (LTE-A)), fifth generation (5G) communications, etc. 4G communications may be performed in frequency bands below 6 gigahertz (GHz), and 5G communications may be performed in frequency bands above 6 GHz. For example, for 4G and 5G communications, the multiple communication nodes may support at least one of the following communication protocols: a communication protocol based on code division multiple access (CDMA), a communication protocol based on wideband CDMA (WCDMA), a communication protocol based on time division multiple access (TDMA), a communication protocol based on frequency division multiple access (FDMA), a communication protocol based on orthogonal frequency division multiplexing (OFDM), a communication protocol based on orthogonal frequency division multiple access (OFDMA), a communication protocol based on cyclic prefix OFDM (CP-OFDM), a communication protocol based on discrete Fourier transform spread OFDM (DFT-s-OFDM), a communication protocol based on single carrier FDMA (SC-FDMA), a communication protocol based on non-orthogonal multiple access (NOMA, non-orthogonal Multiple access) communication protocol, generalized frequency division multiplexing (GFDM) communication protocol, filter bank multi-carrier (FBMC) communication protocol, universal filtered multi-carrier (UFMC) communication protocol, space division multiple access (SDMA) communication protocol, radio access technology (RAT) communication protocol capable of multiple accesses according to a beamforming scheme using massive antennas, etc. Each of the multiple communication nodes may have the following structure.

[0056] Figure 2 is a block diagram showing a first embodiment of a communication node constituting a cellular communication system.

[0057] refer to Figure 2 , the communication node 200 may include a transceiver 230 connected to a network to perform communication, a memory 220, and at least one processor 210. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 may communicate with each other as it is connected via a bus 270.

[0058] The processor 210 may execute a program stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which the method according to an embodiment of the present disclosure is executed. Each of the memory 220 and the storage device 260 may be composed of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0059] Reference again Figure 1 , the communication system 100 may include a plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2, and a plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. The communication system 100 including the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 and the terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may be referred to as an 'access network'. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell, and each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3 and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. In addition, the second terminal 130-2, the fourth terminal 130-4 and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. In addition, the fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5 and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. In addition, the first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1, and the sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

[0060] Here, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can be referred to as an advanced base station (ABS), a high reliability base station (HR-BS), a node B (NodeB), an evolved node B (eNodeB), a gNB, a base transceiver station (BTS), a radio base station, a radio transceiver, an access point (AP), an access node, a radio access station (RAS), a mobile multihop relay base station (MMR-BS), a relay station (RS), an advanced relay station (ARS), a high reliability relay station (HR-RS), a small base station, a femto base station, a pico base station, a macro base station, a micro base station, a home NodeB (HNB), a home eNodeB (HeNB), a road side unit (RSU) unit), radio remote head (RRH), transmission point (TP), transmission and reception point (TRP), etc. In addition, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can perform all or part of the functions of the above-mentioned entities (e.g., ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR-RS, small base station, RSU, RRH, TP, TRP, etc.).

[0061] Each of the multiple terminals 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6 can be called a user equipment (UE), a terminal equipment (TE), a mobile terminal (MT), a mobile station, an advanced mobile station (AMS), a high reliability-mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a device, a station, an Internet of things (IoT) device, an installation module, an on-board unit (OBU), etc. In addition, each of the multiple terminals 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6 can perform all or part of the functions of the above-mentioned entities (e.g., MT, MS, AMS, HR-MS, SS, PSS, AT, UE, IoT device, installation module, etc.).

[0062] At the same time, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can operate in the same frequency band or in different frequency bands. The multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can be connected to each other via an ideal backhaul or a non-ideal backhaul, and exchange information with each other via an ideal or non-ideal backhaul. In addition, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can be connected to the core network via an ideal or non-ideal backhaul. Each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can send a signal received from the core network to the corresponding terminal 130-1, 130-2, 130-3, 130-4, 130-5 or 130-6, and send a signal received from the corresponding terminal 130-1, 130-2, 130-3, 130-4, 130-5 or 130-6 to the core network.

[0063] In addition, each of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 can support multiple-input multiple-output (MIMO) transmission (for example, single-user MIMO (SU-MIMO), multi-user MIMO (MU-MIMO), massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in unlicensed bands, device-to-device (D2D) communication (or proximity service (ProSe)), etc. Here, each of the multiple terminals 130-1, 130-2, 130-3, 130-4, 130-5 and 130-6 can perform operations corresponding to the operations of the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2 (i.e., operations supported by the multiple base stations 110-1, 110-2, 110-3, 120-1 and 120-2). For example, the second base station 110-2 can send a signal to the fourth terminal 130-4 in SU-MIMO mode, and the fourth terminal 130-4 can receive a signal from the second base station 110-2 in SU-MIMO mode. Optionally, the second base station 110-2 can send a signal to the fourth terminal 130-4 and the fifth terminal 130-5 in MU-MIMO mode, and the fourth terminal 130-4 and the fifth terminal 130-5 can receive a signal from the second base station 110-2 in MU-MIMO mode.

[0064] The first base station 110-1, the second base station 110-2 and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 in a CoMP transmission manner, and the fourth terminal 130-4 may receive a signal from the first base station 110-1, the second base station 110-2 and the third base station 110-3 in a CoMP manner. In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1 and 120-2 may exchange signals with a corresponding terminal 130-1, 130-2, 130-3, 130-4, 130-5 or 130-6 belonging to its cell coverage in a CA manner. Each of base stations 110-1, 110-2, and 110-3 may control D2D communication between the fourth terminal 130-4 and the fifth terminal 130-5, and thus the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D communication under the control of the second base station 110-2 and the third base station 110-3.

[0065] Meanwhile, in the communication system, the base station may perform all functions (e.g., remote radio transmission and reception functions, baseband processing functions, etc.) according to the communication protocol. Optionally, the remote radio transmission and reception functions among all functions according to the communication protocol may be performed by a transmission reception point (TRP), and the baseband processing functions among all functions according to the communication protocol may be performed by a baseband unit (BBU) block. The TRP may be a remote radio head (RRH), a radio unit (RU), a transmission point (TP), etc. The BBU block may include at least one BBU or at least one digital unit (DU). The BBU block may be referred to as a 'BBU pool', a 'centralized BBU', etc. The TRP may be connected to the BBU block via a wired fronthaul link or a wireless fronthaul link. The communication system consisting of a backhaul link and a fronthaul link may be as follows. When the function split technique of the communication protocol is applied, the TRP may selectively perform some functions of the BBU or some functions of the MAC / RLC layer.

[0066] Figure 3 is a conceptual diagram showing a second embodiment of a communication system.

[0067] refer to Figure 3 , the communication system may include a core network and an access network. The core network may include MME 310-1, S-GW310-2, P-GW 310-3, etc. The access network may include a macro base station 320, a small base station 330, TRPs 350-1 and 350-2, terminals 360-1, 360-2, 360-3, 360-4, and 360-5, etc. TRPs 350-1 and 350-2 may support remote radio transmission and reception functions among all functions according to the communication protocol, and the baseband processing functions for TRPs 350-1 and 350-2 may be performed by the BBU block 340. The BBU block 340 may belong to the access network or the core network. Communication nodes (e.g., MME, S-GW, P-GW, macro base stations, small base stations, TRPs, terminals, and BBU blocks) belonging to the communication system may communicate with Figure 2 The communication node 200 shown in FIG. 1 is configured identically or similarly.

[0068] The macro base station 320 may be connected to the core network (e.g., MME 310-1, S-GW 310-2) using a wired backhaul link or a wireless backhaul link, and the macro base station 320 provides communication services to the terminals 360-3 and 360-4 based on a communication protocol (e.g., 4G communication protocol, 5G communication protocol). The small base station 330 may be connected to the core network (e.g., MME 310-1, S-GW 310-2) using a wired backhaul link or a wireless backhaul link, and the small base station 330 may provide communication services to the terminal 360-5 based on a communication protocol (e.g., 4G communication protocol, 5G communication protocol).

[0069] The BBU block 340 may be located in the MME 310-1, the S-GW 310-2, or the macro base station 320. Alternatively, the BBU block 340 may be located independently of each of the MME 310-1, the S-GW 310-2, and the macro base station 320. For example, the BBU block 340 may be configured as a logical function between the macro base station 320 and the MME 310-1 (or the S-GW 310-2). The BBU block 340 may support multiple TRPs 350-1 and 350-2, and the BBU block 340 may be connected to each of the multiple TRPs 350-1 and 350-2 using a wired fronthaul link or a wireless fronthaul link. That is, the link between the BBU block 340 and the TRPs 350-1 and 350-2 may be referred to as a 'fronthaul link'.

[0070] The first TRP 350-1 may be connected to the BBU block 340 via a wired fronthaul link or a wireless fronthaul link, and the first TRP 350-1 provides communication services to the first terminal 360-1 based on a communication protocol (e.g., 4G communication protocol, 5G communication protocol). The second TRP 350-2 may be connected to the BBU block 340 via a wired fronthaul link or a wireless fronthaul link, and the second TRP 350-2 provides communication services to the second terminal 360-2 based on a communication protocol (e.g., 4G communication protocol, 5G communication protocol).

[0071] Meanwhile, in the embodiments to be described below, the communication system including the access network, the Xhaul network and the core network may be referred to as an 'integrated communication system'. Communication nodes (e.g., MME, S-GW, P-GW, BBU block, Xhaul distributed unit (XDU, Xhaul distributed unit), Xhaul control unit (XCU, Xhaul control unit), base station, TRP, terminal, etc.) may be connected to the access network, the Xhaul network and the core network. Figure 2The communication nodes 200 shown in FIG. 1 are configured identically or similarly. An Xhaul link may be used to connect communication nodes belonging to an Xhaul network, and the Xhaul link may be a backhaul link or a fronthaul link.

[0072] In addition, the S-GW of the integrated communication system may refer to an end communication node of the core network that exchanges packets (e.g., control information, data) with the base station, and the MME of the integrated communication system may refer to a communication node in the core network that performs a control function for the wireless access part (or interface) of the terminal. Here, each of the backhaul link, fronthaul link, Xhaul link, XDU, XCU, BBU block, S-GW and MME may be referred to as different terms according to the function of the communication protocol depending on the radio access technology (RAT) (e.g., the function of the Xhaul network, the function of the core network).

[0073] Figure 4 is a conceptual diagram showing a first embodiment of an integrated communication system.

[0074] refer to Figure 4 The integrated communication system may include an access network, an Xhaul network, and a core network. The Xhaul network may be located between the access network and the core network and may support communication between the access network and the core network. The communication nodes belonging to the integrated communication system may be configured to communicate with Figure 2 The communication node 200 shown in FIG. 4 is the same or similar to the communication node 200 shown in FIG. The access network may include a TRP 430, a terminal 440, etc. The Xhaul network may include a plurality of communication nodes 420-1, 420-2, and 420-3. The communication nodes constituting the Xhaul network may be referred to as 'XDU'. In the Xhaul network, a wireless Xhaul link may be used to connect the XDUs 420-1, 420-2, and 420-3, and the XDUs 420-1, 420-2, and 420-3 may be connected based on a multi-hop scheme. The core network may include an S-GW / MME 410-1, a P-GW 410-2, etc. The S-GW / MME 410-1 may refer to a communication node including an S-GW and an MME. The BBU block 450 may be located in the S-GW / MME 410-1, and the BBU block 450 may be connected to the third XDU 420-3 via a wired link.

[0075] A first XDU 420-1 of the Xhaul network may be connected to a TRP 430 using a wired link. Alternatively, the first XDU 420-1 may be integrated into the TRP 430. A second XDU 420-2 may be connected to each of the first XDU 420-1 and the third XDU 420-3 using a wireless link (e.g., a wireless Xhaul link), and the third XDU 420-3 may be connected to an end communication node (e.g., S-GW / MME 410-1) of the core network using a wired link. Among the multiple XDUs 420-1, 420-2, and 420-3 of the Xhaul network, the XDU connected to the end communication node of the core network may be referred to as an 'XDU aggregator'. That is, the third XDU 420-3 in the Xhaul network may be an XDU aggregator. The function of the XDU aggregator may be performed by the S-GW / MME 410-1 in the core network.

[0076] The communication between the plurality of XDUs 420-1, 420-2, and 420-3 may be performed using a communication protocol for an Xhaul link (hereinafter, 'Xhaul protocol'), which is different from an access protocol (e.g., a protocol communication used for communication between a terminal 440 and a TRP 430 (or a macro base station, a small base station)). A packet to which the Xhaul protocol is applied may be transmitted to each of a core network and an access network via the Xhaul link. Here, the packet may indicate control information, data, etc.

[0077] The TRP 430 may provide communication services to the terminal 440 using an access protocol (e.g., a 4G communication protocol, a 5G communication protocol), and may be connected to the first XDU 420-1 using a wired link. The TRP 430 may support a long-range radio transmission and reception function among all functions according to the communication protocol, and a baseband processing function for the TRP 430 may be performed in the BBU block 450. The link between the TRP 430 that performs the long-range radio transmission and reception function and the BBU block 450 that performs the baseband processing function (e.g., "TRP 430—first XDU 420-1—second XDU 420-2—third XDU 420-3—BBU block 450 (or SGW / MME 410-1)") may be referred to as a 'fronthaul link'. For example, the fronthaul link may be configured differently depending on the location of the BBU block 450 that performs the baseband processing function.

[0078] Figure 5 is a conceptual diagram showing a second embodiment of the integrated communication system.

[0079] refer to Figure 5The integrated communication system may include an access network, an Xhaul network, and a core network. The Xhaul network may be located between the access network and the core network and may support communication between the access network and the core network. The communication nodes belonging to the integrated communication system may be configured to communicate with Figure 2 The communication nodes 200 shown in FIG. 5 are the same or similar. The access network may include a macro base station 530, a small base station 540, a TRP 550, terminals 560-1, 560-2, and 560-3, etc. The Xhaul network may include a plurality of communication nodes 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6. The communication nodes constituting the Xhaul network may be referred to as 'XDUs'. In the Xhaul network, the XDUs 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6 may be connected using wireless Xhaul links, and the XDUs 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6 may be connected based on a multi-hop scheme. The BBU block 570 may be located in one XDU among the plurality of XDUs 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6. For example, the BBU block 570 may be located in the sixth XDU 520-6. The core network may include an S-GW MME 510-1, a P-GW 510-2, and the like. The S-GW / MME 510-1 may refer to a communication node including an S-GW and an MME.

[0080] The first XDU 520-1 of the Xhaul network may be connected to the macro base station 530 using a wired link, or the first XDU 520-1 of the Xhaul network may be integrated into the macro base station 530. The second XDU 520-2 of the Xhaul network may be connected to the small base station 540 using a wired link, or the second XDU 520-2 of the Xhaul network may be integrated into the small base station 540. The fifth XDU 520-5 of the Xhaul network may be connected to the TRP 550 using a wired link, or the fifth XDU 520-5 of the Xhaul network may be integrated into the TRP 550.

[0081] The fourth XDU 520-4 may be connected to an end communication node (e.g., S-GW / MME 510-1) of the core network using a wired link. Among the multiple XDUs 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6, the XDU connected to the end communication node of the core network may be referred to as an 'XDU aggregator'. That is, the fourth XDU 520-4 may be an XDU aggregator. The Xhaul protocol may be used to perform communication between the multiple XDUs 520-1, 520-2, 520-3, 520-4, 520-5, and 520-6. Packets (e.g., data, control information) to which the Xhaul protocol is applied may be transmitted to each of the core network and the access network via the Xhaul link.

[0082] The macro base station 530 may provide communication services to the first terminal 560-1 using an access protocol (e.g., 4G communication protocol, 5G communication protocol), and may be connected to the first XDU 520-1 via a wired link. The macro base station 530 may be connected to the core network via an Xhaul network, and the link of "macro base station 530—first XDU 520-1—fourth XDU 540-4—S-GW / MME 510-1" may be referred to as a 'backhaul link'. The small base station 540 may provide communication services to the second terminal 560-2 using an access protocol (e.g., 4G communication protocol, 5G communication protocol), and may be connected to the second XDU 520-2 using a wired link. The small base station 540 may be connected to the core network via an Xhaul network, and the link of "small base station 540—second XDU 520-2—third XDU540-3—fourth XDU 540-4—S-GW / MME 510-1" may be referred to as a 'backhaul link'.

[0083] The TRP 550 may provide a communication service to the third terminal 560-3 using an access protocol (e.g., 4G communication protocol, 5G communication protocol), and may be connected to the fifth XDU 520-5 using a wired link. The TRP 550 may support a long-range radio transmission and reception function among all functions according to the communication protocol, and a baseband processing function for the TRP 550 may be performed in the BBU block 570. The link between the TRP 550 that performs the remote radio transmission and reception function and the BBU block 570 that performs the baseband processing function (e.g., the link of “TRP 550—fifth XDU 520-5—BBU block 570 (or sixth XDU 520-6)”) may be referred to as a ‘fronthaul link’, and the link between the BBU block 570 and the S-GW / MME 510-1 (e.g., the link of “BBU block 570 (or sixth XDU 520-6)—fourth XDU 520-4—S-GW / MME 510-1”) may be referred to as a ‘backhaul link’. For example, the fronthaul link may be configured differently depending on the location of the BBU block 570 that performs the baseband processing function.

[0084] Next, an access control method for minimizing a system information acquisition process in a communication system will be described. Even when describing a method to be performed at a first communication node among communication nodes (e.g., transmission or reception of a signal), the corresponding second communication node may also perform a method corresponding to the method performed at the first communication node (e.g., reception or transmission of a signal). That is, when describing the operation of a terminal, the corresponding base station may perform an operation corresponding to the operation of the terminal. Conversely, when describing the operation of a base station, the corresponding terminal may perform an operation corresponding to the operation of the base station.

[0085] Figure 6 is a conceptual diagram showing a third embodiment of a communication system.

[0086] refer to Figure 6 , the communication system may include a first base station 610 - 1 , a second base station 610 - 2 , a third base station 610 - 3 , a terminal 620 , and the like. Figure 6 The communication system can belong to Figure 1 A communication system 100, Figure 3 communication systems, Figure 4 integrated communications system, or Figure 5 For example, the embodiments described below may be applied to a macro base station, a small base station, a TRP, an XDU, a terminal, etc. of an integrated communication system. Base stations 610-1, 610-2, and 610-3 and terminals may be configured to communicate with Figure 2 The communication node 200 shown in FIG.

[0087] The communication system may have multiple service areas (SAs), and a control entity (e.g., MME, S-GW, or P-GW) of the communication system may manage or control each of the multiple SAs. Base stations 610-1, 610-2, 610-3 (e.g., cell coverage of base stations 610-1, 610-2, and 610-3) may belong to one service area, and the cell coverage of base stations 610-1, 610-2, and 610-3 may overlap with each other. For example, base stations 610-1, 610-2, and 610-3 may be located in a specific area (e.g., a crossroads, a junction of roads, a branch point of roads, etc.). Base stations 610-1, 610-2, and 610-3 may be interconnected via a wired interface (e.g., an X2 interface) or a wireless interface. Terminal 620 may have mobility. For example, terminal 620 may move in the cell coverage of each base station 610-1, 610-2, and 610-3.

[0088] When multiple base stations 610-1, 610-2, and 610-3 are located in a specific area (e.g., a service area), in order to effectively control the terminals located in the specific area (e.g., the service area) and improve the performance of the communication system, public resources and public information for multiple base stations 610-1, 610-2, and 610-3 can be configured. Here, the service area can be the entire area or a partial area of ​​the communication system. Public resources and public information can be configured equally and shared by multiple base stations 610-1, 610-2, and 610-3 belonging to a service area. Public resources and public information can be configured by a control entity of the communication system, in which case the control entity of the communication system can notify multiple base stations 610-1, 610-2, and 610-3 of the public resources and public information.

[0089] Optionally, public resources and public information can be configured via a negotiation procedure between multiple base stations 610-1, 610-2 and 610-3. For example, multiple base stations 610-1, 610-2 and 610-3 can use a wired interface or a wireless interface to perform a negotiation process for configuring public resources and public information. In this case, multiple base stations 610-1, 610-2 and 610-3 can exchange terminal-related information (e.g., density, moving path, moving speed, etc.) related to terminals belonging to the cell coverage range with each other, and determine the size of public resources based on the terminal-related information. The process for determining the size of public resources can be performed at a pre-configured time or non-periodically (e.g., when a pre-configured event occurs). For example, when a pre-configured event occurs, multiple base stations 610-1, 610-2 and 610-3 can start a process for determining the size of public resources. Alternatively, when a preconfigured event occurs, the terminal 620 may request the plurality of base stations 610 - 1 , 610 - 2 , and 610 - 3 to perform a process of determining a size of a common resource.

[0090] The common information may indicate the same information used in multiple base stations 610-1, 610-2, and 610-3, and the common information may be transmitted via common resources. The common information may include system information, control information, physical channel configuration / allocation information, reference signal configuration / allocation information, resource allocation information, etc. In addition, the common information may also include an SA identifier indicating a service area to which the common information is applied, a duration indicator indicating a valid duration for which the common information is effectively used, etc. For example, the common information including the SA identifier may be equally applied to multiple base stations belonging to a service area to which the same SA identifier is applied. Therefore, even when a base station (e.g., a cell coverage of a base station to which the terminal 620 belongs) changes in a corresponding service area to which the same SA identifier is applied according to the movement of the terminal 620, the terminal 620 may use the already stored common information instead of newly acquiring the common information (e.g., configuration / allocation information of a physical channel (such as a random access resource) and system information) as described above. However, if another SA identifier is applied to a new base station (or cell), the terminal 620 may perform a process for newly acquiring common information.

[0091] In the case where the public information is applied to the entire area of ​​the communication system, the SA identifier and the duration indicator can be omitted from the public information. Here, the terminal 620 can determine whether to use the public information for communication with the corresponding base station (e.g., the first base station 610-1, the second base station 610-2, or the third base station 610-1) (e.g., a random access process, a cell selection process, a cell reselection process, etc.) based on the SA identifier and the duration indicator included in the public information. Optionally, the public information can be masked based on a specific code sequence to indicate the service area to which the public information is applied, and the public information may include a reference signal having a specific pattern to indicate the service area to which the public information is applied.

[0092] The resource allocation information may include downlink resource allocation information and uplink resource allocation information. For example, the resource allocation information may include resource allocation information for a control channel, resource allocation information for a random access process, resource allocation information for a scheduling request process (e.g., a resource request process), resource allocation information for a downlink transmission request, resource allocation information for D2D communication (e.g., a resource pool for a discovery process, a resource pool for a data transmission and reception process, resource allocation information for a control signal transmission and reception process), etc.

[0093] Resource allocation information may include center frequency, system bandwidth, subcarrier index, etc. as parameters for indicating frequency resources. In addition, resource allocation information may include radio frame index (e.g., system frame number (SFN)), subframe index, transmission time index (TTI), time slot index, micro-time slot index, symbol index, transmission and reception time related information (e.g., time period, interval, window), etc. Here, the index may indicate a number. In addition, resource allocation information may include resource hopping mode, beamforming related information (e.g., beam configuration information, beam index), code sequence (e.g., bit sequence, signal sequence), etc.

[0094] Meanwhile, a common resource through which common information is transmitted may be configured as follows.

[0095] Figure 7 is a conceptual diagram showing a first embodiment of a common resource in a communication system.

[0096] refer to Figure 7 , band #1 can be assigned to Figure 6 For the first base station 610-1, frequency band #2 may be allocated Figure 6 The second base station 610-2, and the frequency band #3 can be allocated to Figure 6The third base station 610-3. The multiple base stations 610-1, 610-2 and 610-3 can perform communication using the allocated frequency band. At least one of the public resource #1 and the public resource #2 can be used for the transmission of public information, and the allocation mode of each of the public resource #1 and the public resource #2 can be configured differently (e.g., allocated frequency resources, allocated time resources, allocated time period, etc.).

[0097] For example, the position of common resource #1 in the frequency axis may be a central region of a frequency band allocated to each of the plurality of base stations 610-1, 610-2, and 610-3, and the position of common resource #2 in the frequency axis may be an edge region of a frequency band allocated to each of the plurality of base stations 610-1, 610-2, and 610-3. When a radio frame includes 10 subframes, common resource #1 may be allocated every 5 subframes in the time axis, and common resource #2 may be allocated every 20 subframes (e.g., 2 radio frames) in the time axis.

[0098] In this case, multiple base stations 610-1, 610-2 and 610-3 can use public resources configured in different frequency bands to send public information. However, the position of the public resources in the timeline can be the same in frequency bands #0 to #3. For example, the first base station 610-1 can use at least one of the public resources #1 and public resources #2 configured in frequency band #1 to send public information, the second base station 610-2 can use at least one of the public resources #1 and public resources #2 configured in frequency band #2 to send public information, and the third base station 610-3 can use at least one of the public resources #1 and public resources #2 configured in frequency band #3 to send public information. In addition, each of public resources #1 and public resources #2 can be used for downlink transmission, uplink transmission, sidelink transmission, etc.

[0099] Figure 8 is a conceptual diagram showing a second embodiment of a common resource in a communication system.

[0100] refer to Figure 8 , Band #1 can be assigned to Figure 6 The first base station 610-1 can allocate frequency band #2 to Figure 6 The second base station 610-2 and the frequency band #3 can be allocated to Figure 6The third base station 610-3. Multiple base stations 610-1, 610-2 and 610-3 can use the allocated frequency band to perform communication. Public resources for the transmission of public information can be configured in frequency band #2. For example, the position of the public resources in the frequency axis can be the edge area of ​​frequency band #2. When the radio frame includes 10 subframes, public resources can be allocated every 20 subframes (e.g., 2 radio frames) in the time axis. In this case, multiple base stations 610-1, 610-2 and 610-3 can use the same public resources (e.g., public resources configured in frequency band #2) to send public information. In addition, public resources can be used for downlink transmission, uplink transmission, sidelink transmission, etc.

[0101] Figure 7 and Figure 8 The configuration information of the common resources shown in may include an allocation mode (e.g., allocated frequency resources, allocated time resources, allocated period, etc.). The allocation period of the common resources may be configured as: a multiple of the minimum period of the scheduling (e.g., resource allocation) specified in the communication system, or an absolute time. For example, when the minimum period of the scheduling is a symbol, the allocation period of the common resources may be configured as a multiple of the symbol, and when the minimum period of the scheduling is a TTI, the allocation period of the common resources may be configured as a multiple of the TTI. Optionally, the allocation period of the common resources may be configured as microseconds, milliseconds, seconds, minutes, etc., which are absolute time units. Multiple base stations 610-1, 610-2, and 610-3 may notify the terminal 620 of the configuration information of the common resources via a system information transmission process or a separate control information signaling process. Here, the signaling process may mean a process for transmitting control information using a dedicated control message of the RRC layer, a control message of the MAC layer (e.g., a MAC control PDU or a MAC control element), a control field or parameter of a physical layer control channel, etc.

[0102] At the same time, the common resources can be configured according to the type of information included in the common information. For example, the common resources for the resource allocation information of the control channel, the resource allocation information for the random access process, the resource allocation information for the scheduling request, and the resource allocation information for the downlink transmission request can be configured differently from each other. In this case, Figure 7 The common resource #1 in the control channel can be used for transmission of resource allocation information of the control channel, and Figure 7 The common resource #2 in the random access procedure may be used for transmission of resource allocation information of the random access procedure. Common resources for common information including different types of information may be configured differently in the multiple base stations 610-1, 610-2, and 610-3, and common resources for common information including the same type of information may be configured equally in the multiple base stations 610-1, 610-2, and 610-3.

[0103] At the same time, the use of common information including resource allocation information for the random access process (or, resource allocation information for scheduling requests, resource allocation information for downlink transmission requests) may mean that multiple base stations 610-1, 610-2 and 610-3 configure the resources used for the random access process (for example, resources for scheduling requests, resources for downlink transmission requests) to be absolutely the same or relatively the same.

[0104] Configuring resources to be absolutely identical may mean using the same values ​​(or the same range) to configure parameters indicating frequency resources (e.g., subcarrier index), parameters indicating time resources (e.g., radio frame index, subframe index, TTI, time slot index, mini-time slot index, symbol index, etc.), sending and receiving time-related information (e.g., time period, interval, window), resource hopping pattern, beamforming-related information (e.g., beam configuration information, beam index), and code sequence (e.g., bit sequence, signal sequence).

[0105] Configuring resources to be relatively the same may mean configuring each of a parameter indicating frequency resources, a parameter indicating time resources, information related to transmission and reception time, a resource hopping pattern, beamforming related information, and a code sequence based on a reference value and an offset. Even when the coverage of a cell to which the terminal 620 belongs changes, the terminal 620 can identify the common resources of the base station supporting the coverage of the cell to which the terminal 620 belongs by using the reference value and the offset.

[0106] For example, the position of the common resource in the frequency axis can be determined by a reference value and an offset (e.g., x subcarriers) of a subcarrier (e.g., a subcarrier with a maximum frequency or a subcarrier with a minimum frequency in the entire frequency band). Here, x can be a real number, a natural number, or an integer greater than or equal to 0. In addition, the position of the common resource in the time axis can be indicated by a reference value and an offset of each of the parameters indicating the time resource, the transmission and reception time related information, the resource hopping mode, the beamforming related information, and the code sequence.

[0107] In addition, the position of the common resource in the frequency axis or the time axis can be configured by modular operation. For the modular operation, the identifier of the base station, the system bandwidth, the fast Fourier transform (FFT) size, the number of subcarriers, the subcarrier index, the SFN, the number of radio frames (or subframes, symbols), the radio frame index (or subframe index, symbol index), and the sequence for identifying the base station (or base station group) can be used.

[0108] At the same time, the reference-based Figures 6 to 8 The public information acquisition process of the described embodiment.

[0109] Fig. 9 is a sequence diagram showing a first embodiment of a common information acquisition process in a communication system.

[0110] refer to Fig. 9 , the communication system may include a first base station 610 - 1 , a second base station 610 - 2 , a third base station 610 - 3 , a terminal 620 , and the like. Fig. 9 The communication system can be Figure 6 For example, Fig. 9 Each of the first base station 610-1, the second base station 610-2, the third base station 610-3 and the terminal 620 in the Figure 6 The first base station 610-1, the second base station 610-2, the third base station 610-3 and the terminal 620 in the same. Multiple base stations 610-1, 610-2 and 610-3 can be located in one service area, and the terminal 620 can be located in the corresponding service area. In addition, the base stations 610-1, 610-2 and 610-3 and the terminal can be configured to Figure 2 The communication node 200 shown in FIG.

[0111] A plurality of base stations 610-1, 610-2, and 610-3 may perform a process for configuring common resources and common information (S901). Figures 6 to 8 The process for configuring the public resources and public information may be performed in the same or similar manner as described above. For example, a control entity (e.g., MME, S-GW, or P-GW) of the communication system may configure the public resources and public information, and transmit the configured public resources and public information to the multiple base stations 610-1, 610-2, and 610-3. Optionally, the public resources and public information may be configured via a negotiation process between the multiple base stations 610-1, 610-2, and 610-3. The public resources configured in step S901 may be configured with Figure 7 or Figure 8 Here, the common information may indicate the same information used in the multiple base stations 610-1, 610-2, and 610-3. The common information may include system information, control information, physical channel configuration / allocation information, reference signal configuration / allocation information, resource allocation information, an SA identifier indicating a service area to which the common information is applied, a duration indicator indicating a valid duration for which the common information is effectively used, and the like.

[0112] The multiple base stations 610-1, 610-2 and 610-3 may generate configuration information of the common resources. The configuration information of the common resources may include Figure 7 or Figure 8The allocation mode of the common resources shown in (eg, allocated frequency resources, allocated time resources, allocated time period, etc.) The multiple base stations 610-1, 610-2, and 610-3 may transmit configuration information via a system information transmission procedure or a separate control information signaling procedure (S902).

[0113] At the same time, the terminal 920 may have completed the connection establishment process with the first base station 610-1 and can operate in the RRC_connected state. When the terminal 620 is located within the cell coverage of the first base station 610-1 in step S902, the terminal 620 can obtain the configuration information of the public resources from the first base station 610-1 via the system information transmission process or the separate control information signaling process (S903). Therefore, the terminal 620 can identify the locations of the public resources for multiple base stations 610-1, 610-2 and 610-3 based on the configuration information of the public resources. That is, the terminal 620 can identify the public resources for multiple base stations 610-1, 610-2 and 610-3 based on the configuration information of the public resources. Figure 7 or Figure 8 The locations of public resources are shown in .

[0114] Multiple base stations 610-1, 610-2, and 610-3 may send public information by using public resources (S904). The terminal 620 may obtain public information for multiple base stations 610-1, 610-2, and 610-3 by performing a monitoring operation on the public resources identified in step S903 (S905). For example, if the terminal 620 is located within the cell coverage of the first base station 610-1 in steps S904 and S905, the terminal 620 may receive public information from the first base station 610-1. Thereafter, if the terminal 620 moves from the cell coverage of the first base station 610-1 to the cell coverage of the second base station 610-2, the terminal 620 may perform communication (e.g., random access process, scheduling request process, downlink transmission request process, etc.) with the second base station 610-2 by using the public information obtained from the first base station 610-1 in step S905 without performing a process for obtaining the public information of the second base station 610-2. Here, even when the connection establishment process between the terminal 620 and the second base station 610-2 is not completed, the terminal 620 can also perform communication with the second base station 610-2. The terminal 620 can also obtain additional system information (e.g., other system information) from the second base station 610-2 to perform communication with the second base station 610-2.

[0115] Optionally, if the terminal 620 is located within the cell coverage of the second base station 610-2 in steps S904 and S905, the terminal 620 may receive public information from the second base station 610-2 based on the configuration information of the public resources obtained from the first base station 610-1. In this case, the terminal 620 may perform communication (e.g., random access process, scheduling request process, downlink transmission request process, etc.) with the second base station 610-2 by using the public information obtained from the second base station 610. Here, even when the connection establishment process between the terminal 620 and the second base station 610-2 is not completed, the terminal 620 may also perform communication with the second base station 610-2.

[0116] At the same time, when the terminal 620 moves from the cell coverage of the first base station 610-1 to the cell coverage of the second base station 610-2, the terminal can receive at least one of a synchronization signal and a radio resource management (RRM) measurement signal by performing a monitoring operation on a pre-configured resource, so as to acquire synchronization with the second base station 610-2. The pre-configured resource may be a common resource indicated by the configuration information obtained from the first base station 610-1 in step S902. The terminal 620 may acquire synchronization with the second base station 610-2 based on at least one of the RRM measurement signal and the synchronization signal received from the second base station 610-2. That is, the terminal 620 may identify the position of the time resource (e.g., subframe index) configured for the second base station 610-2 and the position of the frequency resource (e.g., resource block (RB) index or subcarrier index) configured for the second base station 610-2.

[0117] The terminal 620 can identify, based on a separate message or public information (e.g., system information included in the public information) received from the first base station 610-1, that the mapping relationship between the public resource #1 and the public resource #2 in the frequency band #1 configured for the first base station 610-1 is equally applied to the frequency band #2 configured for the second base station 610-2. The mapping relationship between the public resource #1 and the public resource #2 can be indicated by the relative difference of the time resource (e.g., subframe index offset) and the relative difference of the frequency resource (e.g., RB index offset, subcarrier index offset). Optionally, the mapping relationship between the public resource #1 and the public resource #2 can be indicated by an absolute index (e.g., absolute value, absolute range).

[0118] When the second base station 610-2 uses the common resource #1 of the frequency band #2 to perform downlink burst transmission, and the terminal 620 uses the common resource #2 of the frequency band #2 to perform uplink burst transmission, the mapping relationship between the common resource #1 and the common resource #2 can be indicated not only by the relative difference of the time-frequency resources, but also by the corresponding relationship between the downlink resources constituting the common resource #1 and the uplink resources constituting the common resource #2. When the mapping relationship between the common resource #1 and the common resource #2 in the frequency band #1 is applied to the frequency band #2, the terminal 620 can omit the process of acquiring the common information of the second base station 610-2 or the process of acquiring the separate physical channel of the second base station 610-2.

[0119] Meanwhile, when downlink burst transmission is performed based on the beamforming scheme in frequency band #1 of the first base station 610-1, the downlink beam may include an analog portion, and when uplink burst transmission is performed based on the beamforming scheme in frequency band #1 of the first base station 610-1, the uplink beam may include an analog portion. The analog portion of the downlink beam and the analog portion of the uplink beam may be elements constituting a virtual sector of the first base station 610-1.

[0120] As in the above embodiment, Figure 8 The terminal 620 that obtains the public information in the frequency band #2 can use the acquired public information to perform the communication with Figure 8 Here, even when the connection establishment process between the terminal 620 and the first base station 610-1 is not completed, the terminal 620 can also perform communication with the first base station 610-1.

[0121] According to the above embodiment, even when the coverage of the cell to which the terminal belongs changes, the terminal can perform communication (e.g., random access process, scheduling request process, downlink transmission request process, etc.) with a base station supporting the current cell coverage by using the public information obtained before the cell coverage changes. That is, the terminal can perform communication with the current base station using the public information obtained from the previous base station without performing the process of acquiring the public information of the current base station.

[0122] ■Beam matching process

[0123] Meanwhile, in a millimeter wave (mmWave) based communication system, communication between a base station and a terminal may be performed based on a beamforming scheme. A beam pairing process may be performed based on the beamforming scheme for communication.

[0124] Fig.10 is a sequence diagram showing a first embodiment of a beam pairing process in a communication system.

[0125] refer to Fig.10 , the communication system may include a first base station 610-1, a terminal 620, and the like. Fig.10 The communication system can be Figure 6 For example, Fig.10 The first base station 610-1 may be Figure 6 The first base station 610-1, and Fig.10 The terminal 620 may be Figure 6 The first base station 610-1 and the terminal 620 may be configured to communicate with Figure 2 In addition, the first base station 610-1 and the terminal 620 may include multiple antennas.

[0126] The first base station 610-1 may configure common resources for the beam pairing process (S1001). Common resources may include resources used for transmission of downlink beams (hereinafter referred to as 'downlink beam resources') and resources used for transmission of uplink beams (hereinafter referred to as 'uplink beam resources'). The first base station 610-1 may Figure 7 The public resource #1 is configured as a downlink beam resource, and Figure 7 The common resource #2 of the LTE-based communication system is configured as an uplink beam resource. Here, the downlink beam resource may be referred to as a 'downlink burst resource', and the uplink beam resource may be referred to as an 'uplink burst resource'. Here, a burst may correspond to a physical resource block (PRB) in an LTE-based communication system, and may indicate a time-frequency resource occupied for transmission of data or control information in a physical layer. In addition, a burst may indicate a resource area used for beamforming.

[0127] The first base station 610-1 may generate configuration information of common resources. The configuration information of common resources may include an allocation mode of downlink beam resources (e.g., allocated frequency resources, allocated time resources, allocated time period, etc.) and an allocation mode of uplink beam resources (e.g., allocated frequency resources, allocated time resources, allocated time period, etc.). In addition, the configuration information of common resources may include mapping relationship information between downlink beam resources and uplink beam resources, rather than an allocation mode of uplink beam resources. The mapping relationship information may include a frequency offset, a time offset, an allocation period offset, etc. between downlink beam resources and uplink beam resources. In addition, the mapping relationship information may be configured so that the allocation information of downlink (or uplink) beam resources corresponds to the allocation information of uplink (or downlink) beam resources, or corresponds according to a pre-configured mapping rule. Here, the allocation information of beam resources may include a subcarrier index in the frequency axis, an index of a constituent unit of the time axis (e.g., a radio frame, a subframe, a symbol, etc.), a beam index according to a beamforming scheme, etc. For example, the uplink beam resources that the terminal 620 can use for the downlink beam resources received for beam pairing may be limited to specific uplink beam resources according to the mapping relationship. Therefore, the first base station 610-1 can identify the resources of the downlink beam received at the terminal 620 for beam pairing (e.g., the resources of the beam sent by the first base station 610-1) by using only the resources of the uplink beam received from the terminal 620.

[0128] The first base station 610-1 may notify the terminal 620 of the configuration information of the common resources via a system information transmission process or a separate control information signaling process (S1002). The terminal 620 may obtain the configuration information of the common resources from the first base station 610-1, and identify the downlink beam resources and the uplink beam resources based on the configuration information of the common resources. The first base station 610-1 may transmit the configuration information of the common resources (e.g., Figure 7 For example, the first base station 610-1 may transmit at least one downlink beam via a public resource #1. Figure 7 The downlink beam #0 is transmitted by using the common resource #1 of the subframe #0 included in the radio frame #0 of Figure 7 The downlink beam #1 is transmitted using the common resource #1 of the subframe #5 included in the radio frame #0 of Figure 7 Downlink beam #2 is transmitted using common resource #1 of subframe #0 included in radio frame #1 of the wireless frame. Here, transmission of the downlink beam may indicate downlink burst transmission or downlink discovery signal transmission.

[0129] The terminal 620 can receive the downlink beam of the first base station 610-1 by performing a monitoring operation on the downlink beam resources, and can determine the transmission beam of the first base station 610-1 based on the received downlink beam (S1004). For example, the terminal 620 can determine the downlink beam with the maximum received signal strength among the downlink beams as the transmission beam of the first base station 610-1. When the transmission beam of the first base station 610-1 is determined, the terminal 620 can send a response message to the first base station 610-1 (S1005). The response message may include an index of the transmission beam of the first base station 610-1 determined in step S1004. In addition, the response message may be a message for a scheduling request, a message including a random access preamble, etc. When a mapping relationship is established between the transmission beam of the first base station 610-1 (e.g., resources of a downlink beam) and the transmission beam of the terminal 620 (e.g., resources of an uplink beam), the response message of the first base station 610-1 may not include the index of the transmission beam of the first base station 610-1. In this case, information related to the uplink beam resources or random access preamble selected according to the mapping relationship may be transmitted via the response message instead of the index of the transmission beam of the first base station 610-1.

[0130] The first base station 610-1 may receive a response message from the terminal 620 and may identify a transmission beam of the first base station 610-1 based on the response message. When the transmission and reception process of the response message is completed, the process for determining the transmission beam of the first base station 610-1 may be terminated.

[0131] At the same time, the determination process of the transmission beam of the terminal 620 may be performed. The determination process of the transmission beam of the terminal 620 may be performed after the determination of the transmission beam of the first base station 610-1. Alternatively, the determination process of the transmission beam of the terminal 620 may be performed independently of the determination process of the transmission beam of the first base station 610-1.

[0132] The terminal 620 may transmit the information to the uplink beam resource (eg, Figure 7 For example, the terminal 620 may transmit at least one uplink beam via the public resource #2 of the wireless communication network (S1006). Figure 7 The uplink beam #0 is transmitted via the public resource #2 of the wireless frame #0 of Figure 7 The uplink beam #1 is transmitted via the public resource #2 of the wireless frame #2 of Figure 7 The uplink beam #2 is transmitted using the common resource #2 of the wireless frame #4 of the wireless frame. Here, the transmission of the uplink beam may indicate an uplink burst transmission or an uplink discovery signal transmission.

[0133] When performing the initial access process between the terminal 620 and the first base station 610-1, the terminal 620 may send a message including a random access preamble via an uplink beam resource. In this case, the terminal 620 may perform uplink burst transmission by repeatedly sending a preamble sequence n times. Alternatively, the terminal 620 may perform uplink burst transmission by sending each of the n preamble sequences once. The n preamble sequences may be calculated based on a function of an identifier (e.g., UE ID) of the terminal 620, an index of a downlink beam resource (e.g., a time slot index, a micro-slot index, a symbol index, etc.), or an index of an uplink beam resource (e.g., a time slot index, a micro-slot index, a symbol index, etc.). Here, n may be an integer of 2 or greater. When the connection establishment process between the terminal 620 and the first base station 610-1 is completed, the terminal 620 may send a sounding reference signal (SRS, soundingreference signal) via an uplink beam resource.

[0134] The first base station 610-1 may receive the uplink beam of the terminal 620 by performing a monitoring operation on the uplink beam resource, and may determine the transmission beam of the terminal 620 based on the received uplink beam (S1007). For example, the first base station 610-1 may determine the uplink beam having the maximum received signal strength among the uplink beams as the transmission beam of the terminal 620. When the transmission beam of the terminal 620 is determined, the first base station 610-1 may notify the terminal 620 of the index of the transmission beam of the terminal 620 determined in step S1007. However, when the transmission beam of the terminal 620 is determined according to the above-mentioned mapping relationship between the transmission beam of the first base station 610-1 (e.g., downlink beam resource) and the transmission beam of the terminal 620 (e.g., uplink beam resource), the process for the first base station 610-1 to notify the index of the transmission beam of the terminal 620 may be omitted. When the transmission beam of the first base station 610 - 1 and the transmission beam of the terminal 620 are determined, each of the first base station 610 - 1 and the terminal 620 may perform communication using the transmission beam.

[0135] ■Random access process according to the terminal status

[0136] Meanwhile, the random access procedure may be classified into a random access procedure for initial access (hereinafter referred to as 'initial random access procedure') and a random access procedure for non-initial access (hereinafter referred to as 'non-initial random access procedure'). The initial random access procedure may be performed without context information. The context information may be RRC context information, access stratum (AS) configuration information, etc. The context information may include: RRC configuration information for the terminal, security configuration information, packet data convergence protocol (PDCP) information (e.g., PDCP information according to robust header compression (ROHC) mode), an identifier of the terminal (e.g., cell-radio network temporary identifier (C-RNTI)), an identifier of the base station, etc.

[0137] The non-initial random access procedure can be performed for a communication procedure based on the arrival of transmitted data (or received data), a connection recovery procedure, a resource allocation request procedure, a terminal-based transmission request procedure, a link reconfiguration request procedure after a radio link failure (RLF), a mobility support procedure (e.g., a handover procedure), a secondary cell addition / change procedure, an active beam addition / change procedure, an access request procedure for synchronization acquisition, and the like.

[0138] The initial random access procedure or the non-initial random access procedure may be performed according to the operation state of the terminal. The operation state of the terminal may be as follows.

[0139] Fig.11 is a conceptual diagram showing an operation state of a terminal in a communication system.

[0140] refer to Fig.11, the terminal can operate in the RRC_idle (RRC_idle) state, the RRC_connected (RRC_connected) state or the RRC_inactive (RRC_inactive) state. In addition, the radio access network connection state (RAN_connected state) may include the RRC_connected state and the RRC_inactive state. In the RAN_connected state, the base station and the terminal can store and manage context information, connection configuration information, etc. That is, the RAN_connected state may be a connection state in which context information or connection configuration information is stored and managed between the network and the terminal, and may be distinguished from the connection state from the RRC connection perspective. For example, the connection state from the RRC connection perspective may mean that a data radio bearer is configured and maintained. For a terminal operating in the RRC_connected state, control channels, reference signals, etc. used for connection configuration maintenance and data transmission and reception processes may be configured. The reference signal may be a demodulation reference signal (DMRS, demodulation reference signal) used to demodulate data, an SRS used to measure channel quality, a reference signal used for beamforming, etc. Therefore, the terminal operating in the RRC_connected state can perform data transmission and reception procedures without additional delay.

[0141] Context information, connection configuration information, etc. for a terminal operating in an RRC_inactive state may be stored and managed in a base station and a corresponding terminal. However, in the RRC_inactive state, the terminal may operate similarly to the RRC_idle state. Therefore, a terminal operating in the RRC_inactive state may perform a non-initial random access procedure to perform a data transmission and reception procedure because the data radio bearer has been released or the configuration of the data radio bearer has been stopped. When the non-initial random access procedure is completed, the operating state of the terminal may be changed from the RRC_inactive state to the RRC_connected state, and the terminal operating in the RRC_connected state may perform a data transmission and reception procedure by using the configured data radio bearer. Optionally, a terminal in the RRC_inactive state may send data of a limited size, data according to a limited service quality, data according to a limited service, etc.

[0142] In the RRC_idle state, the connection between the base station and the terminal may not be established, and the context information and connection configuration information of the terminal may not be stored in the base station and the corresponding terminal. Therefore, the terminal operating in the RRC_idle state can perform an initial random access process. In this case, the operating state of the terminal can be changed from the RRC_idle state to the RRC_connected state.

[0143] Optionally, according to the control of the base station, the operating state of the terminal can be changed from the RRC_idle state to the RRC_inactive state, and limited services can be provided for the terminal operating in the RRC_inactive state. Here, the operating state of the terminal can be changed from the RRC_idle state to the RRC_inactive state through a separately defined random access process. Whether to perform the transition from the RRC_idle state to the RRC_inactive state can be determined according to the type of the terminal, the capability of the terminal, the type of service, etc. The base station (or the control entity of the communication system) can configure the transition condition from the RRC_idle state to the RRC_inactive state, and control the transition operation from the RRC_idle state to the RRC_inactive state according to the transition condition. For example, when the base station (or the control entity of the communication system) allows the transition from the RRC_idle state to the RRC_inactive state, the operating state of the terminal can be changed from the RRC_idle state to the RRC_inactive state.

[0144] At the same time, the resources used for the above-mentioned random access process can be cell-specific resources. When common resources for random access procedures are configured in multiple cells (e.g., multiple base stations), an identifier or a virtual cell identifier for distinguishing a specific area can be used to identify common resources. For example, common resources for initial random access procedures can be identified by a virtual cell identifier. When the virtual cell identifier includes a downlink identifier and an uplink identifier, downlink resources among common resources can be identified by the downlink identifier, and uplink resources among common resources can be identified by the uplink identifier.

[0145] When a frequency division duplex (FDD) scheme is used in a communication system, downlink resources and uplink resources may always exist. On the other hand, when a time division duplex (TDD) scheme is used in a communication system, downlink resources and uplink resources may exist independently for each base station. In a TDD-based communication system, when multiple base stations use the same uplink-downlink (UL-DL) configuration, common resources for the multiple base stations may be configured. The terminal may obtain configuration information of common resources from any base station belonging to a base station group (e.g., a group of base stations sharing common resources). Therefore, the position of the common resources in the time axis may be set to belong to such resources (e.g., downlink resources, uplink resources) as follows: all base stations belonging to the base station group have the resources in common.

[0146] For example, when common resources are used for downlink transmission, resources configured as downlink resources (e.g., downlink subframes) in all base stations belonging to the base station group can be configured as common resources. When common resources are used for uplink transmission or sidelink transmission, resources configured as uplink resources (e.g., uplink subframes) in all base stations belonging to the base station group can be configured as common resources.

[0147] Meanwhile, when the FDD scheme is used in the NR communication system, downlink resources and uplink resources may always exist. On the other hand, when the TDD scheme is used in the NR communication system, downlink resources and uplink resources may exist independently for each base station. For example, when the dynamic TDD scheme is used in the NR communication system, the position of each of the downlink subframe (or downlink time slot) and the uplink subframe (or uplink time slot) in one base station may be different from the position of each of the downlink subframe (or downlink time slot) and the uplink subframe (or uplink time slot) in another base station.

[0148] Some of the multiple base stations sharing common resources may operate based on a dynamic TDD scheme, and the remaining base stations may operate based on a semi-static TDD scheme. Optionally, all base stations sharing common resources may operate based on a dynamic TDD scheme. When a dynamic TDD scheme is used in an NR communication system, the type of resources located in a specific area on the time axis may be fixed as downlink resources or uplink resources, and the resources fixed as downlink resources or uplink resources may be configured as common resources. The pattern of fixed resources may be indicated based on a time period and an offset. The base station may notify the terminal of the time period and offset indicating the pattern of fixed resources via a separate control information signaling process or a system information transmission process, and the terminal may identify the pattern of fixed resources based on the obtained time period and offset.

[0149] For example, the fixed resources may be RRM measurement resources, resources for random access procedures (e.g., physical random access channel (PRACH)), etc. The base station may configure downlink resources (e.g., subframes, time slots, mini-time slots) for RRM measurements according to a preset period (e.g., 40 ms), and use the configured downlink resources to send an RRM reference signal (RRM RS). In addition, the base station may configure uplink resources (e.g., subframes, time slots, mini-time slots) for random access procedures according to a preset period (e.g., 2 ms).

[0150] ■Downlink transmission request process

[0151] Next, we will describe the Figures 7 to 9 The downlink transmission request process of the described embodiment. In the downlink transmission request process, the terminal may send a message to the base station requesting the transmission of necessary information, and obtain the necessary information from the base station. Here, the necessary information may be information required for the operation (e.g., service) of the terminal, firmware (e.g., software update information for the terminal), etc. In addition, the necessary information may include signaling information (e.g., dedicated control messages) and public information (e.g., system information) transmitted in a broadcast manner. The necessary information may be as shown in Table 1 below.

[0152] [Table 1]

[0153]

[0154] Fig.12 is a sequence diagram showing a first embodiment of a downlink transmission request procedure in a communication system.

[0155] refer to Fig.12, the communication system may include a first base station 610-1, a terminal 620, and the like. Fig.12 The communication system can be Figure 6 For example, Fig.12 The first base station 610-1 may be Figure 6 The first base station 610-1, and Fig.12 The terminal 620 may be Figure 6 The first base station 610-1 and the terminal 620 may be configured to communicate with Figure 2 The communication node 200 shown in FIG.

[0156] The first base station 610-1 may send public information via a public resource (S1201). Step S1201 may be related to Fig. 9 The common information may include system information, control information, physical channel configuration / allocation information, reference signal configuration / allocation information, resource allocation information, an SA identifier indicating a service area to which the common information is applied, a duration indicator indicating a valid duration for which the common information is effectively used, etc. The resource allocation information may include resource allocation information for a control channel, resource allocation information for a random access procedure, resource allocation information for a scheduling request procedure (e.g., a resource request procedure), resource allocation information for a downlink transmission request (e.g., resource allocation information for a downlink transmission request procedure), resource allocation information for D2D communication, etc.

[0157] The terminal 620 may receive the public information from the first base station 610-1, and identify the resource allocation information for the downlink transmission request process included in the public information. The resource allocation information for the downlink transmission request process may include a parameter indicating a frequency resource, a parameter indicating a time resource, a resource hopping pattern, beamforming related information, a code sequence (e.g., a bit sequence, a signal sequence), and the like.

[0158] The resource allocation information may indicate different resources according to the information elements listed in Table 1. For example, information element #1 of Table 1 may be mapped to code sequence #1 indicated by the resource allocation information, and information element #2 of Table 1 may be mapped to code sequence #2 indicated by the resource allocation information. Therefore, when information element #1 is required, the terminal 620 may send a request message including code sequence #1 to the first base station 610-1, and when code sequence #1 is received from the terminal 620, the first base station 610-1 may send a response message including information element #1 corresponding to code sequence #1 to the terminal 620. Here, the code sequence may be a preamble sequence used in a random access procedure.

[0159] In addition, information element #3 of Table 1 may be mapped to time-frequency resource #1 indicated by resource allocation information, and information element #4 of Table 1 may be mapped to time-frequency resource #2. Therefore, when information element #3 is needed, terminal 620 may send a request message to first base station 610-1 by using time-frequency resource #1, and when receiving the request message via time-frequency resource #1, first base station 610-1 may send a response message including information element #3 corresponding to time-frequency resource #1 to terminal 620. Here, time-frequency resource may be a resource used in a random access process. The mapping relationship between the information element of Table 1 and the resource indicated by the resource allocation information may be sent from first base station 610-1 to terminal 620 via a common information transmission process, a system information transmission process, a control information signaling process, and the like.

[0160] At the same time, the terminal 620 can identify the resources mapped to the necessary information (for example, the information elements described in Table 1) based on the resource allocation information included in the public information, and send a request message to the first base station 610-1 by using the identified resources (S1201). Figure 7 or Figure 8 For example, when information element #2 is needed, terminal 620 may send a request message including code sequence #2 to first base station 610-1, and when information element #4 is needed, terminal 620 may send a request message to first base station 610-1 by using time-frequency resource #2. Here, the request message may be a message used in a random access process (e.g., a random access preamble).

[0161] Optionally, the request message may be configured using a physical layer control channel or a control channel of a MAC layer or higher layer. In this case, the value of a specific field included in the request message and the information element described in Table 1 may be mapped. For example, a specific field set to '100' may request the transmission of information element #5 of Table 1, and a specific field set to '101' may request the transmission of information element #6 of Table 1. The mapping relationship between the information element described in Table 1 and the value of the specific field may be sent from the first base station 610 to the terminal 620 via a common information transmission process, a system information transmission process, a control information signaling process, etc.

[0162] The first base station 610-1 may receive a request message from the terminal 620, and may identify information to be sent to the terminal 620 based on the request message. For example, when the request message includes code sequence #2, the first base station 610-1 may determine that transmission of information element #2 of table 1 corresponding to code sequence #2 is requested. When the request message is received via time-frequency resource #2, the first base station 610-1 may determine that transmission of information element #4 of table 1 corresponding to time-frequency resource #2 is requested. When a specific field of the request message is set to '100', the first base station 610-1 may determine that transmission of information element #5 of table 1 corresponding to the specific field set to '100' is requested.

[0163] The first base station 610-1 may generate a response message including the information element to be transmitted, and may transmit the response message to the terminal 620 (S1203). Figure 7 or Figure 8 The terminal 620 may send the response message using the common resource shown in or the downlink radio resource of each base station (eg, the first base station 610-1). The terminal 620 may receive the response message from the first base station 610-1 and identify the information element included in the response information.

[0164] ■Random access process

[0165] Next, we will describe the Figures 7 to 9 as well as Fig.12 The random access procedure of the described embodiments.

[0166] Fig.13 is a sequence diagram showing a first embodiment of a random access procedure in a communication system.

[0167] refer to Fig.13 , the communication system may include a first base station 610 - 1 , a second base station 610 - 2 , a terminal 620 , and the like. Fig.13 The communication system can be Figure 6 For example, Fig.13 The first base station 610-1 may be Figure 6 The first base station 610-1, Fig.13 The second base station 610-2 may be Figure 6 The second base station 610-2, and Fig.13 The terminal 620 may be Figure 6 The first base station 610-1, the second base station 610-2 and the terminal 620 may be configured to communicate with Figure 2 The communication node 200 shown in FIG.

[0168] The first base station 610-1 may send public information via a public resource (S1301). Step S1301 may be related to Fig. 9 The common information may be configured identically in multiple base stations (e.g., the first base station 610-1 and the second base station 610-2). The common information may include system information, control information, physical channel configuration / allocation information, reference signal configuration / allocation information, resource allocation information, an SA identifier indicating a service area to which the common information is applied, a duration indicator indicating a valid duration for which the common information is effectively used, and the like. The resource allocation information may include resource allocation information for control channels, resource allocation information for random access procedures, resource allocation information for scheduling request procedures (e.g., resource request procedures), resource allocation information for downlink transmission request procedures, resource allocation information for D2D communication, and the like. The resource allocation information may include parameters indicating frequency resources (e.g., reference values ​​and offsets), parameters indicating time resources (e.g., reference values ​​and offsets), resource hopping patterns, beamforming related information, code sequences (e.g., bit sequences, signal sequences), inactivated radio resource areas (or durations), and the like.

[0169] The terminal 620 may belong to the cell coverage of the first base station, and the connection establishment process between the terminal 620 and the first base station 610-1 may be completed. The terminal 620 may receive public information from the first base station 610-1, and identify the resource allocation information for the random access process (or downlink transmission request process) included in the public information. The resource allocation information for the random access process (or downlink transmission request process) may include parameters indicating frequency resources, parameters indicating time resources, resource hopping patterns, beamforming related information, code sequences (e.g., bit sequences, signal sequences), etc.

[0170] At the same time, the first base station 610-1 can send public information based on a beam scanning scheme (e.g., a downlink burst transmission scheme). In this case, the public information can be sent in multiple virtual sectors of the first base station 610-1 in a time division multiplexing (TDM, time division multiplex) manner. For example, the first base station 610-1 can configure broadcast information for each virtual sector (e.g., a mapping relationship between resources for transmission of downlink control information and resources for a random access process), and send the broadcast information via public resources based on a beam scanning scheme. Considering the signaling overhead in the communication system, it may be desirable to establish the same mapping relationship in the virtual sectors of the first base station 610-1. In this case, the first base station 610-1 can repeatedly send the same broadcast information based on a downlink burst transmission scheme, and when the broadcast information is received only once from the first base station 610-1, the terminal 620 can identify the broadcast information of the first base station 610-1.

[0171] When the terminal 620 moves from the cell coverage of the first base station 610-1 to the cell coverage of the second base station 610-2, the terminal 620 can perform communication (e.g., random access process, downlink transmission request process, etc.) with the second base station 610-2 by using the public information (e.g., broadcast information) obtained from the first base station 610-1. In this case, the terminal 620 can perform communication with the second base station 610-2 without performing the process of obtaining public information from the second base station 610-2. Optionally, the terminal 620 can communicate with the second base station 610-2 after obtaining part of the system information (e.g., the remaining system information, other system information) from the second base station 610-2.

[0172] The terminal 620 may send a random access preamble to the second base station 610-2 by using the resources indicated by the public information acquired from the first base station 610-1 (or, when performing a downlink transmission request procedure, Fig.12 The second base station 610-2 may receive a random access preamble code (or, Fig.12 The terminal 620 may receive a response message to the random access preamble (or, a response message including the information requested by the terminal 620 (e.g., the information element of Table 1)) from the second base station 610-2. Fig.12 Response message in step S1203).

[0173] The response message received in step S1303 may include scheduling information for the signaling message in step S1305. The scheduling information may include: an identifier of the base station (e.g., the second base station 610-2) that sends the signaling message of step S1305, a beam index, an indicator for identifying scheduling information, resource allocation information, modulation and coding scheme (MCS) information, resource allocation information for transmission of feedback messages (e.g., acknowledgment (ACK) message, negative ACK (NACK) message), etc. The resource allocation information may include parameters indicating frequency resources, parameters indicating time resources, information related to sending and receiving time (e.g., time period, interval, window), etc.

[0174] At the same time, multiple base stations may receive the random access preamble of the terminal 620, in which case each of the multiple base stations may send a random access response to the terminal 620. Here, the random access response may include an identifier of the base station (e.g., a cell identifier). When receiving random access responses from multiple base stations, the terminal 620 may select a base station that satisfies a preconfigured condition from among the multiple base stations. Here, the preconfigured condition may be included in the random access response in step S1303. Optionally, the terminal 620 may arbitrarily select a base station from among the multiple base stations. The terminal 620 may perform steps S1304 and S1305 with the selected base station.

[0175] When the downlink transmission request process is performed, the response message of step S1303 may include necessary system information (e.g., master information block (MIB)), scheduling information of system information (e.g., system information block (SIB1)), configuration information of the physical layer channel of the corresponding base station (e.g., SIB2), system information for specific functions (e.g., MBMS, D2D communication, machine type communication (MTC), IoT, vehicle communication (e.g., vehicle to everything (V2X)), alarms for disasters and social safety nets, transmission of location information and public time, intercommunication with other RAT systems, etc.), updated system information, etc.

[0176] When receiving the response message from the second base station 610-2, the terminal 620 may send a signaling message including information about the terminal 620 to the second base station 610-2 (S1304). The information about the terminal 620 may include an identifier, capabilities, attributes, mobile status, location, etc. In addition, the signaling message of step S1304 may be used to request necessary information. That is, the signaling message of step S1304 may be configured to be Fig.12The request message of step S1202 is the same as that of step S1204. In addition, when the information element requested by the terminal 620 (e.g., the information element in Table 1) is not identified in step S1302 alone, the signaling message of step S1304 may be sent. That is, when the required information element requested by the terminal 620 is identified in step S1302 alone, step S1304 may be omitted. When step S1304 is performed, the second base station 610-2 that has received the signaling message requesting the required information may generate a signaling message including the information requested by the terminal 620 (e.g., the information element in Table 1), and send the signaling message to the terminal 620 (S1305). The terminal 620 may receive the signaling message from the second base station 610-2, and may identify the information included in the signaling message. Here, step S1305 may be selectively performed. That is, when the requested information does not exist, the terminal 620 may not perform step S1305.

[0177] On the other hand, the terminal 620 can communicate with a third base station (eg, Figure 6 The third base station 610-3 shown in FIG. 1 performs steps S1304 and S1305 instead of the second base station 610-2. Here, the RAT supported by the third base station 610-3 (e.g., system bandwidth, transmission carrier, and configuration of the protocol layer) may be different from the RAT supported by the first base station 610-1 and the second base station 610-2 (e.g., system bandwidth, transmission carrier, and configuration of the protocol layer). The common information of step S1301 may be shared by base stations 610-1, 610-2, and 610-3, and the common information may be used for a random access procedure between the terminal 620 and the base stations 610-1, 610-2, and 610-3, a procedure for requesting necessary information (e.g., a downlink transmission request procedure), and the like.

[0178] For example, in step S1304, the terminal 620 may send a signaling message requesting necessary information to the third base station 610-3, and the third base station 610-3 may receive the signaling message from the terminal 620. In step S1305, the third base station 610-3 may generate a signaling message including the information requested by the terminal 620 (e.g., the information element of Table 1), and send the signaling message to the terminal 620. Therefore, the terminal 620 may receive the signaling message from the third base station 610-3, and may identify the information included in the signaling message.

[0179] Meanwhile, physical layer synchronization of base stations 610-1, 610-2, and 610-3 may be considered during transmission and reception between the terminal 620 and the base stations 610-1, 610-2, and 610-3. When the first base station 610-1 and the second base station 610-2 operate in a TDD manner, it may be assumed that the first base station 610-1 is synchronized with the second base station 610-2. However, when the first base station 610-1 and the second base station 610-2 operate in an FDD manner, it may be assumed that the first base station 610-1 is not synchronized with the second base station 610-2. Therefore, even when common resources are configured between the first base station 610-1 and the second base station 610-2, the position of the common resources of the first base station 610-1 on the time axis may be different from the position of the common resources of the second base station 610-2.

[0180] For example, when a random access procedure is performed using common resources, the time point at which the terminal 620 sends a random access preamble to the first base station 610-1 may be different from the time point at which the terminal 620 sends a random access preamble to the second base station 610-2. That is, because the random access procedure for the first base station 610-1 is performed according to the uplink subframe boundary of the first base station 610-1, and the random access procedure for the second base station 610-2 is performed according to the uplink subframe boundary of the second base station 610-2, the transmission time point of the random access preamble for the first base station 610-1 may be different from the transmission time point of the random access preamble for the second base station 610-2.

[0181] Therefore, the terminal 620 that has acquired the configuration information of the common resource from the first base station 610-1 can acquire uplink synchronization with the second base station 610-2 in order to perform a random access procedure with the second base station 610-2. After acquiring uplink synchronization with the second base station 610-2, the terminal 620 can estimate the resources (e.g., PRACH) used for the random access procedure with the second base station 610-2 by using the configuration information of the common resource obtained from the first base station 610-1, and send a random access preamble to the second base station 610-2 via the estimated resources.

[0182] At the same time, since the terminal 620 can perform a random access process with all base stations (e.g., the first base station 610-1, the second base station 610-2, and the third base station 610-3) sharing the common resources by using the common resources, the terminal 620 may not perform an RRM measurement process for determining the target base station (e.g., the second base station 610-2) for performing the random access process. However, the terminal 620 may use the reference signal of the second base station 610-2 to determine the transmission power of the random access preamble and for power climbing. For example, the terminal 620 may estimate the downlink path loss based on the reference signal of the second base station 610-2, and may determine the transmission power for the random access preamble based on the estimated path loss.

[0183] In addition, the terminal 620 may receive control information of the target base station (e.g., the second base station 610-2) to receive a random access response. In order to receive the control information of the second base station 610-2, the terminal 620 may not only obtain the downlink synchronization information of the second base station 610-2, but also may obtain the information necessary for demodulating the control information (e.g., system bandwidth, physical hybrid-ARQ (automatic repeat request) indicator channel (PHICH) resource configuration information, SFN, cell-specific reference signal (CRS, cell-specific reference signal) port configuration information, etc.). In an LTE-based communication system, the terminal 620 may obtain the information necessary for demodulating the control information via the MIB. In an NR communication system, the terminal 620 may obtain the information necessary for demodulating the control information via system information (e.g., minimum system information, necessary system information) transmitted in a MIB or broadcast scheme. The information necessary for demodulating the control information may include: scheduling information of other system information, configuration information of multiple radio frames, configuration information of subcarrier spacing of bandwidth sets, and allocation (or configuration) parameters of the physical layer control channel on the frequency (or time) axis according to symbol configuration.

[0184] The system information transmitted in a broadcast manner may be commonly applied to multiple base stations (e.g., multiple cells). The terminal 620 may determine the public information (e.g., already obtained public information, new public information to be obtained) used for the random access procedure (or cell selection procedure, cell reselection procedure) based on the SA identifier included in the public information, information indicating the validity of the system information (e.g., a duration indicator indicating the effective duration of the public information being effectively used, a tag, information notifying that the system information will change, etc.), etc.

[0185] ■A process for transmitting system information based on an on-demand scheme

[0186] Next, a process for transmitting system information based on an on-demand scheme will be described. The process for transmitting system information based on an on-demand scheme may be performed based on a random access process. For example, when additional system information is required, the terminal may perform a random access process. An identifier and a radio resource for a random access process performed to request additional system information may be configured separately. A base station may receive a random access preamble requesting transmission of additional system information from a terminal, and may send a random access response including the additional system information requested by the terminal to the terminal. The terminal may receive a random access response from a base station, and may identify the additional system information included in the random access response.

[0187] Meanwhile, the system information may be managed using a tag. When receiving the system information from the base station, the terminal may check the tag included in the system information. When the tag indicates that an additional system information is required, the terminal may send a request message to the base station requesting transmission of the additional system information. When receiving the request message from the terminal, the base station may send the additional system information to the terminal. The terminal may obtain the additional system information from the base station, and when the additional system information is obtained, the process of transmitting the system information may be terminated.

[0188] Optionally, when the tag indicates that two additional system information are required, the terminal may send a request message to the base station requesting transmission of the two additional system information. The request message may include corresponding identifiers of the two additional system information. When the request message is received from the terminal, the base station may send the two additional system information (e.g., the two additional system information indicated by the identifier included in the request message) to the terminal. The terminal may obtain the two additional system information from the base station, and when the two additional system information are obtained, the process of transmitting the system information may be terminated.

[0189] At the same time, when the system information changes (e.g., updated), the base station can notify the terminal that the system information has changed. The information indicating that the system information has changed can be indicated by a bitmap or a label (e.g., a label of a SIB unit). Here, when the system information consists of multiple system information blocks (SIBs), the bits of the bitmap can be configured for each SIB, and the value label of the SIB can be configured for each SIB. Therefore, the bit of the bitmap or the value label of the SIB can indicate the validity of the corresponding SIB mapped with the bit or value. For example, a specific bit set to 0 in the bitmap can indicate that the SIB corresponding to the specific bit has not changed, and a specific bit set to 1 in the bitmap can indicate that the SIB corresponding to the specific bit has changed. Therefore, the terminal can identify the changed system information based on the bitmap or label obtained from the base station. In addition, the terminal can identify the changed system information by comparing the current bitmap (or label) with the previous bitmap (or label).

[0190] In the case where the system information is classified into minimum system information and other system information, the base station may notify the terminal whether the minimum system information and other system information have been changed respectively. The minimum system information may be referred to as necessary system information, basic system information, etc., and other system information may be referred to as additional system information, etc. The minimum system information may be public control information transmitted through SIB. Other system information may be system information other than the minimum system information among all system information.

[0191] In addition, the minimum system information can be classified into primary minimum system information and secondary minimum system information. The minimum system information may include a tag and a bitmap indicating that the system information has changed. The secondary minimum system information may include: scheduling information for the transmission of other system information, multi-radio frame configuration information, configuration information of the physical layer control channel, etc. Here, in the case of configuring the radio frame of the corresponding cell (or base station) in one or more frame formats, the multi-radio frame configuration information may include: configuration parameters of the micro-slots and subframes constituting the radio frame, subcarrier spacing, and configuration parameters for symbols, etc. In addition, the configuration information of the physical layer control channel may include: bandwidth configuration parameters for multi-radio frame configuration or data / control information transmission, radio resource allocation parameters for the physical layer control channel allocated to each bandwidth (for example, configuration information of radio resource elements in the time and frequency axis, transmission period, transmission interval, transmission symbol interval of data / control information, etc.), etc.

[0192] The primary minimum system information and the secondary minimum system information may be transmitted via different channels, respectively. For example, the primary minimum system information may be transmitted via a physical broadcast channel (PBCH), and the secondary minimum system information may be transmitted via a physical downlink shared channel (PDSCH) or other PBCH. Here, the time-frequency resources of the PBCH for transmitting the primary minimum system information may be different from the time-frequency resources of the PBCH for transmitting the secondary minimum system information. The secondary minimum system information transmitted via the PDSCH may be transmitted in a specific beamforming unit (e.g., a beamforming group unit) using a broadcast scheme, a multicast scheme, or a unicast scheme. That is, the secondary minimum system information transmitted via the PDSCH may not be transmitted in a broadcast manner throughout the entire cell.

[0193] An identifier (e.g., minimum system information-radio network temporary identifier (SI-RNTI)) may be configured for scheduling information of a PBCH or PDSCH via which the secondary minimum system information is transmitted. Therefore, the terminal may perform a monitoring operation on a pre-configured time-frequency resource to obtain the minimum system information (e.g., primary minimum system information and secondary minimum system information). Alternatively, the terminal may search for an identifier (e.g., minimum SI-RNTI) for scheduling information of the minimum system information (e.g., primary minimum system information and secondary minimum system information).

[0194] That is, when the primary minimum system information is transmitted through the PBCH and the secondary minimum system information is transmitted through the PDSCH, the terminal can receive the secondary minimum system information via the radio resources repeatedly allocated according to the predetermined period in the communication system or by monitoring the minimum SI-RNTI. In this case, the scheduling information of the radio resources of the PDSCH via which the secondary minimum system information is transmitted can be included in the primary minimum system information. The scheduling information may include: configuration information of the radio resources via which the secondary minimum system information is transmitted, a transmission period, or an index (or index offset) configured according to a multi-radio frame.

[0195] At the same time, control information indicating that each of the minimum system information and other system information has changed may be transmitted via separate resources. For example, the channel (e.g., channel occurrence period) via which the control information indicating that the minimum system information has changed is transmitted may be different from the channel (e.g., channel occurrence period) via which the control information indicating that other system information has changed is transmitted. In addition, each of the scheduling information (e.g., scheduling identifier, and configuration information of the control field in the scheduling information) and the scrambling sequence used to transmit the control information indicating that the minimum system information has changed may be different from each of the scheduling information (e.g., scheduling identifier, and configuration information of the control field in the scheduling information) and the scrambling sequence used to transmit the control information indicating that other system information has changed. In the case where the minimum system information is classified into primary minimum system information and secondary minimum system information, control information indicating that each of the primary minimum system information and the secondary minimum system information has changed may be transmitted via separate resources.

[0196] Information indicating that the system information has changed (e.g., updated) may be signaled by a control channel (e.g., a control message) transmitted in a beamforming unit (e.g., in a beamforming group unit). Here, the control channel (e.g., a control message) may also include information notifying that the system information will change. Information indicating that the system information has changed may be expressed in a bitmap or a tag. The bitmap may be composed of a bit sequence, and each of the bits contained in the bit sequence may be mapped to the corresponding system information (e.g., SIB). Whether the system information mapped to the bit has changed may be indicated by the corresponding bit value. Information for notifying that the system information will change may be configured for each SIB, and the information may indicate a modification period (or a change time point) of the corresponding system information. When the information for notifying that the system information will change indicates a change time point, the change time point may be indicated by a hyper frame number (HFN), SFN, subframe index, etc. Optionally, the change time point may be indicated by an absolute time (e.g., milliseconds, seconds, minutes, hours, etc.). Optionally, a timer may be used to indicate the change time point. The timer can be expressed in units of mini-slots, time slots, sub-frames, radio frames, milliseconds, seconds, minutes, hours, etc.

[0197] Therefore, the terminal can identify that the system information has changed by receiving information indicating that the system information has changed from the base station. In addition, the terminal can identify that the system information will be changed by receiving information notifying the change of the system information from the base station. In this case, the terminal can perform a process of acquiring the changed system information. The terminal can send a message to the base station requesting the transmission of new system information based on an on-demand scheme before the system information changes, and can receive the new system information (i.e., the changed system information) from the base station. For example, when a pre-configured condition is met, the terminal can identify whether the system information has changed (or will be scheduled to change) before performing a discontinuous reception (DRX) operation, before performing a transition operation from the RRC_connected state to the RRC_idle state, or in any other necessary situation.

[0198] When a change in system information is recognized (or system information is to be changed), the terminal can request the base station to send new system information (i.e., changed system information) in an on-demand scheme, or request the base station to send necessary system information before the system information is changed, and can receive new system information from the base station. A timer indicating a time point at which new system information can be acquired before or after the change in system information can be configured. In this case, the terminal can request the base station to send new system information at a time point indicated by the timer, and can receive new system information from the base station.

[0199] Meanwhile, an IoT terminal, an MTC terminal, or a terminal supporting only an outgoing service (e.g., a mobile originated (MO) service) may not receive a paging channel (hereinafter referred to as an 'incoming paging channel') for an incoming service (e.g., a mobile terminated (MT) service). Information indicating that system information has been changed for a terminal that does not receive a paging channel (hereinafter referred to as a 'calling terminal') may be transmitted via another channel instead of the paging channel.

[0200] Alternatively, a paging channel for transmitting information indicating that system information has changed (hereinafter referred to as a 'system paging channel') may be configured separately from an incoming paging channel. For example, scheduling information for the system paging channel may be configured differently from scheduling information for the incoming paging channel. The scheduling information may be configuration information of a time-frequency resource, a scheduling identifier, a control field in the scheduling information, etc. Therefore, the calling terminal may perform a monitoring operation on the system paging channel instead of the incoming paging channel.

[0201] At the same time, uplink resources (e.g., resources configured for the random access process) may be used to perform a downlink transmission request process based on an on-demand scheme (e.g., a transmission request process of system information). The terminal may send an uplink signal (e.g., a preamble sequence, signaling information, control information, etc.) to the base station to trigger the downlink transmission request process. Here, the preamble sequence may indicate that a downlink transmission request process based on an on-demand scheme is about to start, and the uplink signal that triggers the downlink transmission request process may be a time-frequency resource selected by the terminal or a time-frequency resource configured by the base station.

[0202] In addition, the preamble sequence used for the downlink transmission request process based on the on-demand scheme may be the preamble sequence first sent by the terminal in the random access process or the preamble sequence configured for the system information transmission request process. The preamble sequence may be used to request the transmission of minimum system information (e.g., necessary system information), system information transmitted in a broadcast manner, system information for a specific area (e.g., beamforming unit, beamforming group unit), etc. Here, the necessary system information may be system information including configuration information of physical layer resources (e.g., MIB, SIB1, SIB2, etc.). When the preamble sequence is used to request the transmission of system information according to the on-demand scheme, the preamble sequence (or the configuration information of the radio resource area corresponding to the preamble) may have a mapping relationship with the requested system information. That is, a specific preamble sequence (or the configuration information of the radio resource area corresponding to the preamble, the masking information corresponding to the preamble, etc.) may indicate a specific SIB, or may be configured to have a mapping relationship with a specific SIB among the SIBs constituting the minimum system information or the system information. Here, the configuration information of the radio resource area of ​​the preamble code may include: information indicating the location of the uplink radio resources used to transmit the preamble code, information about the frequency axis such as bandwidth, subcarrier (group), etc., information about the time axis such as frame, subframe, time slot, micro time slot, symbol, etc., beam configuration information according to the beamforming scheme, etc.

[0203] Therefore, the terminal can send a preamble code by selecting a preamble code sequence or a preamble code radio resource area (for example, a radio frame, a subframe, or a transmission band or subcarrier index) according to a mapping relationship while considering the necessary SIB, and the base station (or cell) can identify the SIB to be sent by the terminal using only information about the received preamble code sequence or the radio resource area in which the preamble code is received.

[0204] System information other than the minimum system information (e.g., necessary system information), system information transmitted in a broadcast manner, and system information for a specific area (e.g., beamforming unit, beamforming group unit) may be referred to as 'other system information'. Here, the other system information may be transmitted on a data channel or a multicast channel. In addition, the other system information may be transmitted based on an on-demand scheme.

[0205] In the system information transmission request process based on the on-demand scheme, a bitmap indicating the system information to be transmitted may be used, and the unit of the system information to be transmitted may be a SIB unit or a SIB group unit. Here, the bitmap may include a bit sequence, each bit included in the bit sequence may be mapped to a SIB or a SIB group, and the value of each bit may indicate whether the corresponding system information is requested to be transmitted. For example, a specific bit set to 1 may indicate a request to transmit the SIB (or SIB group) corresponding to the specific bit.

[0206] At the same time, the transmission request process of the minimum system information can be performed based on the uplink resources used to transmit the random access preamble in the random access process. For example, the terminal can use the resources allocated for the random access preamble in the random access process to send a message requesting the transmission of the minimum system information to the base station. The transmission request process of other system information can be performed based on the uplink resources used to transmit message #3 (for example, a message sent by the terminal after receiving the random access response) in the random access process. For example, the terminal can use the resources allocated for message #3 in the random access process to send a message requesting the transmission of other system information to the base station.

[0207] The message requesting transmission of other system information may include information related to transmit and receive beams. When communication based on a beamforming scheme is performed between a base station and a terminal, the information related to transmit and receive beams may include feedback information (e.g., beam configuration information, beam index, beam measurement results, antenna port, etc.) used to determine the best transmit beam and the best receive beam for the base station, information about the transmit beam and receive beam of the terminal, etc.

[0208] Therefore, when receiving a message requesting transmission of other system information from the terminal, the base station can identify the transmit and receive beam related information from the received message, and determine the best beam based on the transmit and receive beam related information. The base station can send a message including other system information, the best beam index, etc. to the terminal, and the terminal can obtain the other system information, the best beam index, etc. by receiving the corresponding message from the base station. In addition, when the index of a specific beam determined by the terminal is included in the transmit and receive beam related information, the base station can use the downlink beam indicated by the index of the specific beam to send other system information to the terminal.

[0209] In addition, the base station may use multiple downlink beams to send system information (e.g., minimum system information, other system information) to the terminal. For example, the base station may use multiple downlink beams to send the same system information at the same time. In addition, the base station may use downlink beams to send system information at different times.

[0210] Meanwhile, in the system information transmission request process based on the on-demand scheme, the system information transmitted from the base station can be received at at least one terminal. When the system information is transmitted via the resources configured for the random access response, one terminal can receive the system information. In this case, the time interval between the resources configured for the random access preamble and the resources configured for the random access response can be kept constant.

[0211] The base station may send the system information to the terminal in response to the transmission request of the system information. Optionally, the base station may send the scheduling information of the system information (e.g., information configured as a physical downlink control channel (PDCCH), information configured as a group common PDCCH) to the terminal in response to the transmission request of the system information. For example, when a message requesting the transmission of the system information is received via the resources configured for the random access preamble, the base station may send the scheduling information of the system information via the resources configured for the random access response.

[0212] Here, the random access preamble may indicate a request to transmit system information. The resources (e.g., time-frequency resources, preamble sequence, etc.) of the random access preamble indicating a request to transmit system information may be configured identically to the resources of the random access preamble used for connection establishment. Alternatively, the resources of the random access preamble indicating a request to transmit system information may be configured differently from the resources of the random access preamble used for connection establishment.

[0213] In addition, the base station may send a random access response including scheduling information of the system information. The random access response may also include information indicating that a random access preamble indicating a request for transmission of system information has been successfully received at the base station. Therefore, when the information indicating that a random access preamble indicating a request for transmission of system information has been successfully received at the base station is not present in the random access response, the terminal may repeatedly send a random access preamble indicating a request for transmission of system information after a preconfigured time (e.g., a timer) has passed. Here, the random access preamble may be repeatedly sent a preconfigured maximum number of times, repeatedly sent using different preamble sequences, and repeatedly sent via different resources. In addition, when a beamforming scheme is used, the random access preamble may be repeatedly sent based on different beam configuration information (e.g., beam indexes).

[0214] Upon receiving a random access preamble indicating a request to transmit system information, the base station may send scheduling information (e.g., information configured as PDCCH, information configured as group common PDCCH) by using a scheduling identifier (e.g., C-RNTI) corresponding to the corresponding system information or a scheduling identifier configured for a system information transmission request process based on an on-demand scheme, and the system information may be sent via the resources indicated by the scheduling information. The terminal may receive scheduling information from the base station based on a scheduling identifier (e.g., a group scheduling identifier). For example, the terminal may receive scheduling information in a receiving window for a random access response or in a receiving window configured for a system information transmission request process based on an on-demand scheme. Here, the receiving window may be configured in units of symbols, mini-slots, time slots, subframes, TTIs, radio frames, microseconds, milliseconds, seconds, etc. When the scheduling information is received, the terminal may receive the system information via the resources indicated by the scheduling information.

[0215] If scheduling information (or system information) is not received within the receiving window, the terminal may resume the system information transmission request process based on the on-demand scheme. Alternatively, a terminal operating in the RRC_idle state or the RRC_inactive state may transition to the RRC_connected state, and the terminal operating in the RRC_connected state may perform the system information transmission request process.

[0216] Meanwhile, when the terminal receives system information from the base station in the system information transmission request procedure based on the on-demand scheme, the terminal operating in the RRC_idle state or the RRC_inactive state may operate as follows.

[0217] A terminal operating in the RRC_idle state or the RRC_inactive state may send a random access preamble code for requesting transmission of system information to a base station, and thereafter, the terminal operating in the RRC_idle state or the RRC_inactive state may transition to the RRC_connected state. A terminal operating in the RRC_connected state may receive system information (e.g., a random access response including system information) from a base station via a unicast resource.

[0218] Optionally, after sending a random access preamble code for requesting transmission of system information, a terminal operating in an RRC_idle state or an RRC_inactive state can receive system information (e.g., a random access response including system information) from a base station via resources indicated by separate scheduling information, multicast resources, or broadcast resources without transitioning to an RRC_connected state.

[0219] The base station may send a control message as follows, the control message including information configured to transmit system information via resources configured for a random access response or resources configured for a system information transmission process based on an on-demand scheme (e.g., scheduling information, information for downlink transmission, resource information). The control message may include control information, control elements, control parameters, control fields, indicator bits (or symbols), etc. of an RRC layer, a MAC layer, or a physical layer.

[0220] For example, the control message may include scheduling information for resources for broadcast transmission, multicast transmission, or unicast transmission, or include a scheduling identifier configured to schedule corresponding resources. Therefore, the terminal can identify the scheduling information included in the control message, or identify the scheduling information based on the scheduling identifier. The terminal can receive system information based on the identified scheduling information. In addition, if the control message received from the base station does not indicate a transition to the RRC_connected state, the terminal can receive system information in the RRC_idle state or the RRC_inactive state.

[0221] Scheduling information for resources (e.g., broadcast resources, multicast resources, or unicast resources) for transmitting system information based on an on-demand scheme may include time resource information (e.g., interval, window, transmission period), frequency resource information (e.g., allocated frequency band, subcarrier index), repeated transmission related information, MCS information, beamforming related information (e.g., beam configuration information, beam index), etc. Therefore, the base station can send the system information based on the scheduling information, and the terminal can receive the system information based on the scheduling information.

[0222] At the same time, when the system information is transmitted via a broadcast channel or a multicast channel, multiple terminals can receive the system information. The base station can semi-statically configure the transmission period and radio resources for the system information to be transmitted via the broadcast channel, and can notify the terminal of the transmission period and radio resources. The terminal can receive the system information based on the transmission period and radio resources obtained from the base station. In addition, when a transmission request for system information based on an on-demand scheme is received from the terminal during the transmission period of the broadcast channel, the base station can broadcast the system information (e.g., the system information requested by the terminal) according to the corresponding transmission period. The system information can be transmitted via a data channel. Since the scheduling information for the system information (e.g., the scheduling information transmitted on the PDCCH) is transmitted based on a common scheduling identifier (e.g., SI-RNTI), all terminals can receive the system information.

[0223] The base station may semi-statically configure the transmission period and radio resources for the system information to be transmitted via the multicast channel, and may notify the terminal of the transmission period and radio resources. The terminal may receive the system information based on the transmission period and radio resources obtained from the base station. Alternatively, the base station may dynamically configure the transmission period and radio resources for the system information to be transmitted via the multicast channel, and send scheduling information for the system information by using a scheduling identifier for multicast transmission (e.g., system information multicast RNTI (SIMC-RNTI)). Therefore, the base station may receive the scheduling information based on the scheduling identifier configured for the system information transmission process based on the on-demand scheme, and receive the system information based on the scheduling information.

[0224] On the other hand, when a message requesting transmission of system information based on an on-demand scheme is not received, the base station may not transmit the system information in a broadcast or multicast manner. Before transmitting a message requesting transmission of system information based on an on-demand scheme, the terminal may recognize whether necessary system information (e.g., system information to be requested by the terminal based on an on-demand scheme) is transmitted by receiving control information of the base station (e.g., scheduling information about the system information, a scheduling identifier).

[0225] For example, when a response to a transmission request for system information (e.g., scheduling information of the system information, a scheduling identifier) ​​of another terminal is received from the base station, and it is determined based on the response that the system information required by the terminal is to be transmitted from the base station within a predetermined time (e.g., a window or a timer), the terminal may not transmit a message requesting transmission of the system information based on an on-demand scheme. On the other hand, when it is determined based on the response that the system information required by the terminal is not transmitted from the base station within a predetermined time (e.g., a window or a timer), the terminal may transmit a message requesting transmission of the system information based on an on-demand scheme. Therefore, the overhead caused by the transmission of the message requesting transmission of the system information based on the on-demand scheme can be reduced.

[0226] At the same time, in order to simplify the system information transmission process based on the on-demand scheme in an environment where the cell coverage is overlapped, the base station can send the system information of the neighboring base station (e.g., the neighboring cell) to the terminal. For example, the terminal can send a message requesting the transmission of system information based on the on-demand scheme. When the terminal moves between the cell coverage or is located in an area where the cell coverage is overlapped, the base station can receive a message requesting the transmission of system information based on the on-demand scheme from the terminal, and send its own system information and the system information of the neighboring base station (e.g., the neighboring cell) to the corresponding terminal. The terminal can obtain the system information of the base station and the system information of the neighboring base station (e.g., the neighboring cell) from the base station. The system information of each base station can be distinguished by a cell identifier. When the terminal moves to the cell coverage of the neighboring base station, the terminal can identify the cell identifier of the neighboring base station based on the reference signal or system information received from the neighboring base station, and when there is system information corresponding to the cell identifier (e.g., the system information of the neighboring base station obtained from the base station), the process of obtaining system information from the neighboring base station may not be performed.

[0227] ■Random access process based on the mapping relationship between resources

[0228] Next, a random access procedure based on a mapping relationship between downlink resources (eg, resources configured for synchronization signal burst transmission) and uplink resources (eg, resources configured for a random access procedure) will be described.

[0229] Fig.14 is a timing diagram showing a first embodiment of a method for transmitting a synchronization signal in a communication system.

[0230] refer to Fig.14 , the synchronization signal block may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH, etc. A synchronization signal burst may include a synchronization signal block transmitted during a period of a synchronization signal burst. The base station may send a synchronization signal burst according to a preconfigured periodicity within a synchronization signal burst set. Here, n may be a positive integer. When a beamforming scheme is used, the base station may send a synchronization signal (e.g., a synchronization signal block, a synchronization signal burst) by using each of all beams in a synchronization signal burst set. Here, the synchronization signal (e.g., a synchronization signal block, a synchronization signal burst) may be repeatedly sent according to preconfigured conditions.

[0231] At the same time, when uplink resources (e.g., resources configured for random access procedures) are mapped to downlink resources (e.g., resources configured for sending synchronization signal bursts), random access preambles can be repeatedly sent via uplink resources (e.g., common resources). For example, common resources shared by multiple base stations can configure synchronization signal burst sets in a preconfigured frequency band or the same frequency band by using the same configuration parameters or configuration parameters to which common rules are applied. A mapping relationship can be established based on the beams supported by the base station so that the terminal can repeatedly send random access preambles. In this case, the terminal can repeatedly send random access preambles without changing the preamble sequence (e.g., code sequence, bit sequence, or signal sequence) selected by the terminal until the synchronization signal burst set (or random access procedure) ends.

[0232] Fig.15 is a conceptual diagram showing a mapping relationship between resources in a communication system.

[0233] refer to Fig.15 , the first base station and the second base station may operate in an FDD scheme. Each of the first base station and the second base station may be connected to Figure 6 The first base station 610-1 and the second base station 610-2 shown in FIG. 6 are the same. Common information for the first base station and the second base station may be configured, and the common information may include: system information (e.g., minimum system information, necessary system information) transmitted in a broadcast manner (or a multicast manner), a synchronization signal (e.g., a synchronization signal block, a synchronization signal burst), etc. In addition, the common information may include system information, control information, physical channel configuration / allocation information, reference signal configuration / allocation information, resource allocation information, etc. The common information may be transmitted via common resources configured for the first base station and the second base station.

[0234] The mapping relationship between the downlink common resources of the first base station and the uplink common resources of the first base station can be configured. Therefore, the terminal that knows the position of the downlink common resources of the first base station can estimate the position of the uplink common resources of the first base station based on the mapping relationship with the position of the downlink common resources of the first base station. The mapping relationship between the downlink common resources of the second base station and the uplink common resources of the second base station can be configured. Therefore, the terminal that knows the position of the downlink common resources of the second base station can estimate the position of the uplink common resources of the second base station based on the mapping relationship with the position of the downlink common resources of the second base station. Here, the downlink common resources can be used for the transmission of public information, and the uplink common resources can be used for random access procedures, scheduling request procedures, downlink transmission request procedures, system information request procedures, etc. The mapping relationship between the downlink common resources and the uplink common resources can be sent to the terminal via a signaling process using an RRC layer dedicated control message, a MAC control PDU, etc., or via a system information transmission process.

[0235] In addition, the uplink common resources can be shared by the first base station and the second base station, and in the first base station and the second base station, the position of the uplink common resources in the time axis can be the same. For example, the PRACH (e.g., PRACH occasion) of the first base station can be configured identically to the PRACH (e.g., PRACH occasion) of the second base station. Here, the fact that the PRACH (e.g., PRACH allocation) of the base station is configured identically can mean that the PRACH is configured based on the same rules according to the above-mentioned absolute or relative scheme. Therefore, the terminal that knows the position of the uplink common resources of the first base station can estimate the position of the uplink common resources of the second base station based on the position of the uplink common resources of the first base station without performing the process of acquiring the system information of the second base station, and use the uplink common resources of the second base station to send a random access preamble to the second base station. Here, the position of the common resources can refer to information indicating the frequency band (e.g., bandwidth, subcarrier (group)), transmission time, transmission and reception beams, etc. of the resource. Therefore, the estimation of the location of the common resources can mean that the terminal obtains the following information, which is indicative information about the transmission band (e.g., bandwidth), transmission time index (e.g., frame, subframe, time slot, mini-time slot, symbol, etc.), mask value, preamble index range, transmission beam index, etc. of the uplink PRACH resources capable of transmitting the random access preamble code.

[0236] The communication process based on the above public resources and public information (for example, random access process, system information transmission process, etc.) can be applied to Figure 4 and Figure 5The integrated communication system shown in . For example, an XDU (or an XDU aggregator) can perform a communication process based on the above-mentioned common resources and common information. That is, multiple XDUs (or multiple XDU aggregators) can configure common resources and can transmit configuration information of common resources. In addition, multiple XDUs (or multiple XDU aggregators) can configure common information and can transmit common information via common resources. Therefore, an XDU with mobility can perform communication (e.g., the above-mentioned operation of a terminal) by using common resources and common information configured by another XDU (or another XDU aggregator).

[0237] The embodiments of the present disclosure may be implemented as program instructions that can be executed by various computers and recorded on computer-readable media. The computer-readable medium may include program instructions, data files, data structures, or a combination thereof. The program instructions recorded on the computer-readable medium may be specifically designed and configured for the present disclosure, or may be well-known and available for use by those skilled in the art of computer software.

[0238] Examples of computer-readable media may include hardware devices such as ROM, RAM, and flash memory, which are particularly configured to store and execute program instructions. Examples of program instructions include machine codes made by, for example, a compiler, and high-level language codes that can be executed by a computer using a translator. The above exemplary hardware devices may be configured to operate as at least one software module to perform embodiments of the present disclosure, and vice versa.

[0239] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of the disclosure.

Claims

1. A method of a user equipment, the method comprising: Receiving main minimum system information from the base station in the physical broadcast channel PBCH; receiving secondary minimum system information from the base station in a radio resource of a physical downlink shared channel PDSCH by monitoring a minimum system information-radio network temporary identifier SI-RNTI, the secondary minimum system information including scheduling information for other system information and bandwidth configuration parameters for control / data information transmission; Sending, to the base station, a message for requesting transmission of the other system information using resources used for a random access RA process; as well as receiving the other system information from the base station, The resource used to request the other system information is configured separately, the resource is selected based on a mapping relationship with the other system information, and the other system information requested to be transmitted is identified through the resource.

2. The method according to claim 1, wherein: The message is a RA preamble message including a preamble sequence.

3. The method according to claim 1, wherein: The resources used to send the message are resources used to send Message 3 in the RA procedure.

4. The method according to claim 1, wherein: The secondary minimum system information is transmitted in a unicast scheme.

5. The method according to claim 1, wherein: The secondary minimum system information is transmitted in a beamforming unit.

6. A method of a base station, the method comprising: Sending primary minimum system information to a user equipment UE in a physical broadcast channel PBCH, wherein the primary minimum system information includes first scheduling information for a radio resource used to send the secondary minimum system information; Sending the secondary minimum system information to the UE in a radio resource of a physical downlink shared channel PDSCH determined based on the first scheduling information, wherein the secondary minimum system information includes second scheduling information for other system information and a bandwidth configuration parameter for control / data information transmission; receiving, from the UE, a message for requesting transmission of the other system information using resources used for a random access RA procedure; as well as sending the other system information to the UE, The resource used to request the other system information is configured separately, the resource is selected based on a mapping relationship with the other system information, and the other system information requested to be transmitted is identified through the resource.

7. The method according to claim 6, wherein: The message is a RA preamble message including a preamble sequence.

8. The method according to claim 6, wherein: The resources used to send the message are resources used to send Message 3 in the RA procedure.

9. The method according to claim 6, wherein: The secondary minimum system information is transmitted in a unicast scheme.

10. The method according to claim 6, wherein: The secondary minimum system information is transmitted in a beamforming unit.

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