Terminal device, method of terminal device, and method of base station

Abstract

This application relates to terminal devices, methods of terminal devices, and methods of base stations. A method for a terminal device is provided, the terminal device being configured to communicate with a first base station, the method comprising: measuring a signal transmitted by a second base station using at least one beam; transmitting first information indicating the result of the measurement to the first base station; receiving an RRC message from the first base station, the RRC message including second information related to the beam, including that the RRC message in an acknowledgment message was transmitted from the second base station to the first base station in response to a request message, and that the request message including the first information was transmitted from the first base station to the second base station; and transmitting a random access preamble signal to the second base station based on the second information.

Description

[0001] This application is a divisional application of the invention patent application filed on July 5, 2017, with application number 201780047632.5, entitled "Apparatus, method, system, procedure and recording medium related to beamforming". Technical Field

[0002] This invention relates to equipment, methods, systems, procedures, and recording media related to beamforming. Background Technology

[0003] To achieve a dramatic increase in mobile network capacity, not only can currently used frequency bands such as those in the hundreds of megahertz and gigahertz ranges be used, but also higher frequency bands such as those in the tens of megahertz ranges. In particular, in fifth-generation (5G) networks, to fully utilize these frequency bands, research has been conducted on using a large number of antennas to form narrow directional beams to transmit signals to users.

[0004] In higher frequency bands, to compensate for greater propagation loss, beamforming can be used to transmit not only system information and paging information, but also all downlink signals / downlink channels, including common pilot signals or reference signals. Similarly, for the uplink, to compensate for propagation loss, beamforming can be used to receive all uplink signals / uplink channels.

[0005] For example, Patent Document 1 discloses a technique in which a handover request message sent from the source base station to the target base station during a handover of a terminal device includes a downlink beam ID and an uplink beam ID. Furthermore, according to Patent Document 1, the downlink beam ID specifies the downlink beam used to transmit data to the terminal device after handover, and the uplink beam ID specifies the uplink beam used to receive data from the terminal device after handover. This allows the operation of selecting a beam during handover to be omitted, thereby reducing handover latency.

[0006] Existing technical documents

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-531852 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, according to the technology disclosed in Patent Document 1, propagation loss is compensated for in the transmission / reception of data after handover, but not in the transmission / reception of control signals between the terminal device and the target base station during handover. In particular, due to the large propagation loss, the target base station may be unable to receive the access signal of the terminal device (e.g., the uplink signal in random access). As a result, this leads to the possibility of an increased handover failure rate.

[0011] The purpose of this invention is to increase the likelihood of a successful switchover.

[0012] Solution for solving the problem

[0013] A first device according to an exemplary aspect of the invention includes: a first communication processing unit configured to transmit a reference signal using beamforming; and a second communication processing unit configured to receive a handover message from a source base station of a terminal device, wherein the handover message includes beam-related information relating to the beam, and the first communication processing unit is configured to receive an access signal of the terminal device based on the beam-related information.

[0014] A second device according to an exemplary aspect of the invention includes: a first communication processing unit configured to receive from a terminal device first beam-related information, the first beam-related information being information used by a base station for transmitting a reference signal using beamforming; and a second communication processing unit configured to transmit a switching message including second beam-related information corresponding to the first beam-related information to the base station, wherein the second beam-related information is information to be used by the base station for receiving an access signal from the terminal device.

[0015] A third device according to an exemplary aspect of the invention includes: a receiving processing unit configured to receive a reference signal transmitted by a first base station using beamforming; and a transmitting processing unit configured to transmit a first beam-related information to a second base station, the first beam-related information being information used by the first base station, wherein the first beam-related information corresponds to a second beam-related information to be used by the first base station for receiving an access signal.

[0016] A first method according to an exemplary aspect of the invention includes: transmitting a reference signal using beamforming; receiving a handover message from a source base station of a handover of a terminal device, the handover message including beam-related information; and receiving an access signal of the terminal device based on the beam-related information.

[0017] A second method according to an exemplary aspect of the invention includes: receiving from a terminal device a first beam-related information relating to a beam, the first beam-related information being information used by a base station for transmitting a reference signal using beamforming; and transmitting a switching message including a second beam-related information corresponding to the first beam-related information to the base station, wherein the second beam-related information is information to be used by the base station for receiving an access signal from the terminal device.

[0018] A third method according to an exemplary aspect of the invention includes: receiving a reference signal transmitted by a first base station using beamforming; and transmitting a first beam-related information to a second base station, the first beam-related information being information used by the first base station, wherein the first beam-related information corresponds to a second beam-related information to be used by the first base station for receiving an access signal.

[0019] A system according to an exemplary aspect of the present invention includes: a first base station; a second base station; and a terminal device, wherein the first base station uses beamforming to transmit a reference signal, the terminal device receives the reference signal and transmits a first beam-related information to the second base station, the first beam-related information being information used by the first base station, the second base station transmits a switching message including a second beam-related information corresponding to the first beam-related information to the first base station, and the first base station receives an access signal from the terminal device based on the second beam-related information.

[0020] A first program according to an exemplary aspect of the invention is a program for causing a processor to perform: transmitting a reference signal using beamforming; receiving a handover message from a source base station of a handover of a terminal device, the handover message including beam-related information; and receiving an access signal of the terminal device based on the beam-related information.

[0021] A second program according to an exemplary aspect of the invention is a program for causing a processor to perform: receiving from a terminal device a first beam-related information relating to a beam, the first beam-related information being information used by a base station for transmitting a reference signal using beamforming; and sending a switching message including a second beam-related information corresponding to the first beam-related information to the base station, wherein the second beam-related information is information to be used by the base station for receiving an access signal from the terminal device.

[0022] A third program according to an exemplary aspect of the invention is a program for causing a processor to perform: receiving a reference signal transmitted by a first base station using beamforming; and transmitting a first beam-related information to a second base station, the first beam-related information being information used by the first base station, wherein the first beam-related information corresponds to a second beam-related information to be used by the first base station for receiving an access signal.

[0023] According to an exemplary aspect of the invention, a first recording medium is a computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute: transmitting a reference signal using beamforming; receiving a handover message from a source base station for handover of a terminal device, the handover message including beam-related information; and receiving an access signal of the terminal device based on the beam-related information.

[0024] According to an exemplary aspect of the invention, a second recording medium is a computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute: receiving from a terminal device a first beam-related information relating to a beam, the first beam-related information being information used by a base station for transmitting a reference signal using beamforming; and transmitting to the base station a switching message including a second beam-related information corresponding to the first beam-related information, wherein the second beam-related information is information to be used by the base station for receiving an access signal from the terminal device.

[0025] According to an exemplary aspect of the invention, a third recording medium is a computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute: receiving a reference signal transmitted by a first base station using beamforming; and transmitting a first beam-related information to a second base station, the first beam-related information being information used by the first base station, wherein the first beam-related information corresponds to a second beam-related information to be used by the first base station for receiving an access signal.

[0026] The effects of the invention

[0027] According to an exemplary aspect of the present invention, the likelihood of a successful switchover can be increased. Note that, in lieu of or in conjunction with the effects described above, the present invention can provide other effects. Attached Figure Description

[0028] Figure 1 This is an explanatory diagram illustrating an example of a schematic structure of a system according to a first embodiment of the present invention.

[0029] Figure 2 This is a block diagram illustrating an example of a schematic structure of a first base station according to a first embodiment.

[0030] Figure 3 This is a block diagram illustrating an example of the schematic structure of the second base station according to the first embodiment.

[0031] Figure 4 This is a block diagram illustrating an example of the schematic structure of a terminal device according to the first embodiment.

[0032] Figure 5 This is an illustrative diagram used to illustrate an example of multiple beams used to transmit a reference signal.

[0033] Figure 6 This is an illustrative diagram used to illustrate an example of wireless resources (time resources) to be used for transmitting reference signals.

[0034] Figure 7 This is an illustrative diagram used to illustrate an example of a measurement report from a terminal device.

[0035] Figure 8 This is a sequence diagram illustrating an example of a schematic flow of the process according to the first embodiment.

[0036] Figure 9 This is an illustrative diagram used to illustrate an example of a wireless resource indicated by resource information.

[0037] Figure 10 This is a sequence diagram illustrating an example of a schematic flow for explaining the processing of a first variation of the first embodiment.

[0038] Figure 11 This is a sequence diagram illustrating the processing flow of a second variation of the first embodiment.

[0039] Figure 12 This is an explanatory diagram illustrating an example of a schematic structure of a system according to the second embodiment.

[0040] Figure 13 This is a block diagram illustrating an example of the schematic structure of the first base station according to the second embodiment.

[0041] Figure 14 This is a block diagram illustrating an example of the schematic structure of a second base station according to the second embodiment.

[0042] Figure 15 This is a block diagram illustrating an example of the schematic structure of a terminal device according to the second embodiment.

[0043] Figure 16 This is a sequence diagram illustrating an example of the schematic flow of the processing in the second embodiment.

[0044] List of reference numerals

[0045] 1,2 system

[0046] 10,20 cells / coverage area

[0047] 11 beams

[0048] 30-beam search time period

[0049] 100, 200, 500, 600 base stations

[0050] 141,241,510,610 First Communication Processing Unit

[0051] 143,243,520,620 Second Communication Processing Unit

[0052] 300, 700 terminal devices

[0053] 331,710 Receiving and Processing Unit

[0054] 333,720 Transmission Processing Unit Detailed Implementation

[0055] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Note that in the specification and drawings, the same reference numerals may be used to denote the same elements, thereby omitting repeated descriptions.

[0056] The explanations will be given in the following order.

[0057] 1. Overview of embodiments of the present invention

[0058] 2. First Embodiment

[0059] 2.1. System Structure

[0060] 2.2. Structure of Base Station 100

[0061] 2.3. Structure of Base Station 200

[0062] 2.4. Structure of Terminal Equipment 300

[0063] 2.5. Technical Features

[0064] 2.6. Variations

[0065] 3. Second Embodiment

[0066] 3.1. System Structure

[0067] 3.2. Structure of Base Station 500

[0068] 3.3. Structure of Base Station 600

[0069] 3.4. Structure of Terminal Equipment 700

[0070] 3.5. Technical Features

[0071] <<1. Overview of Embodiments of the Invention>>

[0072] First, an overview of the embodiments of the present invention will be given.

[0073] (1) Technical issues

[0074] To achieve a dramatic increase in mobile network capacity, not only can currently used frequency bands such as those in the hundreds of megahertz and gigahertz ranges be used, but also higher frequency bands such as those in the tens of megahertz ranges. In particular, in fifth-generation (5G) networks, to fully utilize these frequency bands, research has been conducted on using a large number of antennas to form narrow directional beams to transmit signals to users.

[0075] In higher frequency bands, to compensate for greater propagation loss, beamforming can be used to transmit not only system information and paging information, but also all downlink signals / downlink channels, including common pilot signals or reference signals. Similarly, for the uplink, to compensate for propagation loss, beamforming can be used to receive all uplink signals / uplink channels.

[0076] For example, patent document (Japanese Patent Publication No. 2014-531852) discloses a technique in which a handover request message sent from the source base station to the target base station during a handover of a terminal device includes a downlink beam ID and an uplink beam ID. Furthermore, according to this patent document, the downlink beam ID is used to specify the downlink beam for transmitting data to the terminal device after handover, and the uplink beam ID is used to specify the uplink beam for receiving data from the terminal device after handover. This allows the operation of selecting a beam during handover to be omitted, thereby reducing handover latency.

[0077] However, according to the technology disclosed in this patent document, propagation loss is compensated for in the transmission / reception of data after handover, but not in the transmission / reception of control signals between the terminal device and the target base station during handover. In particular, due to the large propagation loss, the target base station may be unable to receive the access signal of the terminal device (e.g., uplink signal in random access). As a result, this leads to the possibility of an increased handover failure rate.

[0078] Therefore, it is hoped that this can increase the likelihood of a successful switchover.

[0079] (2) Technical features

[0080] In embodiments of the invention, for example, a first base station (a base station located around a terminal device) uses beamforming to transmit a reference signal, and the terminal device measures the reference signal. Furthermore, the terminal device transmits first beam-related information (and measurement results) from the first base station to a second base station (the serving base station of the terminal device). For example, the first beam-related information indicates one of a plurality of sets of beamforming weights (e.g., preferred beamforming weights).

[0081] Then, the terminal device is switched from the second base station (source base station) to the first base station (target base station). In this case, the second base station (source base station) sends a handover message (e.g., a handover request message) to the first base station (target base station) including second beam-related information (e.g., information identical to the first beam-related information) that corresponds to the first beam-related information.

[0082] Specifically, in embodiments of the present invention, the first base station receives the access signal from the terminal device based on second beam-related information. For example, the first base station uses preferred beamforming weights to receive the access signal.

[0083] This allows, for example, compensation for the propagation loss of the access signal. Therefore, the probability of a successful handover can be increased.

[0084] Note that the above-described technical features are specific examples of embodiments of the present invention, and of course, embodiments of the present invention are not limited to the above-described technical features.

[0085] <<2. First Embodiment>>

[0086] Next, refer to Figures 1 to 11 The first embodiment of the present invention will be described below.

[0087] <2.1. System Structure>

[0088] Reference Figure 1 Here is an example illustrating the structure of system 1 according to the first embodiment. Figure 1 This is an explanatory diagram illustrating an example of the schematic structure of system 1 according to the first embodiment. (See reference...) Figure 1 System 1 includes base station 100, base station 200 and terminal equipment 300.

[0089] For example, System 1 can be a system compliant with 3GPP (3rd Generation Partnership Project) standards. More specifically, for example, System 1 can be a system compliant with fifth-generation (5G) standards.

[0090] (1) Base station 100

[0091] Base station 100 performs wireless communication with terminal devices located within cell 10 (or coverage area 10). In a first embodiment, base station 100 uses beamforming for wireless communication.

[0092] Specifically, in the first embodiment, base station 100 uses beamforming to transmit reference signals (RS). Reference signals are signals used to measure received signal strength and / or reception quality, and correspond to, for example, CRS (Cell-Specific Reference Signal) or CSI-RS (Channel State Information Reference Signal) in LTE (Long Term Evolution). Reference signals can be referred to as CRS or CSI-RS as in LTE, or they can be called in different ways (e.g., “XXX Reference Signal” (XXX is any term), “Pilot Signal”, or entirely different signal names). Base station 100 can use beamforming to transmit all types of reference signals (e.g., CRS, CSI-RS, UE-Specific RS, and / or MBSFN (Multicast / Broadcast over Signal Frequency Network) RS). Optionally, base station 100 can use beamforming to transmit some types of reference signals without using beamforming to transmit other types of reference signals.

[0093] Base station 100 uses beamforming to transmit not only data and reference signals, but also other downlink signals / downlink channels (e.g., all signals / channels).

[0094] Note that base station 100 is a node that conducts wireless communication with terminal devices; in other words, it is a node of the RAN (Radio Access Network). For example, base station 100 can be a NodeB, H-NodeB (Home Node B), eNodeB (Evolved Node B), or H-eNodeB (Home Evolved Node B), or it can be a gNodeB (Generator Node B) in 5G. Base station 100 may include multiple units (or multiple nodes). The multiple units (or multiple nodes) may include a first unit (or first node) that processes lower protocol layers and a second unit (or second node) that processes higher protocol layers. As an example, the first unit may be referred to as a DU (Distributed Unit) or AU (Access Unit), and the second unit may be referred to as a CU (Center / Central Unit). As another example, the first unit may be referred to as a RU (Radio Unit) or RU (Remote Unit), and the second unit may be referred to as a DU (Digital Unit). RU may be RRH (Remote Radio Header) or RRU (Remote Radio Unit), and DU may be BBU (Baseband Unit). Of course, the names of the first unit (or first node) and the second unit (or second node) are not limited to these examples. Optionally, base station 100 may be a single unit (or a single node). In this case, base station 100 may be one of the aforementioned multiple units (e.g., one of the first unit and the second unit), or it may be connected to other units among the multiple units (e.g., other units in the first unit and the second unit).

[0095] (2) Base station 200

[0096] Base station 200 conducts wireless communication with terminal devices located in cell 20 (or coverage area 20).

[0097] In the first embodiment, for example, similar to base station 100, base station 200 uses beamforming for wireless communication with the terminal device. Optionally, base station 200 may use beamforming for wireless communication with the terminal device in a different manner than base station 100, or may not use beamforming for wireless communication with the terminal device.

[0098] Note that, like base station 100, base station 200 is also a node that conducts wireless communication with terminal devices; in other words, base station 200 is a node of the RAN.

[0099] (3) Terminal equipment 300

[0100] Terminal device 300 performs wireless communication with a base station. For example, terminal device 300 performs wireless communication with base station 100 when it is located in cell 10, and performs wireless communication with base station 200 when it is located in cell 20.

[0101] Specifically, in the first embodiment, the handover of the terminal device 300 from base station 200 to base station 100 is performed (due to, for example, the movement of the terminal device 300). In this case, base station 200 is the source base station for the handover, and base station 100 is the target base station for the handover.

[0102] <2.2. Structure of Base Station 100>

[0103] Next, refer to Figure 2 Here is an example illustrating the structure of the base station 100 in the first embodiment. Figure 2 This is a block diagram illustrating an example of the schematic structure of the base station 100 according to the first embodiment. (See reference...) Figure 2 The base station 100 includes a wireless communication unit 110, a network communication unit 120, a storage unit 130, and a processing unit 140.

[0104] (1) Wireless communication unit 110

[0105] The wireless communication unit 110 wirelessly transmits / receives signals. For example, the wireless communication unit 110 receives signals from a terminal device and transmits signals to the terminal device.

[0106] (2) Network communication unit 120

[0107] The network communication unit 120 receives signals from the backhaul and sends signals to the backhaul.

[0108] (3) Storage unit 130

[0109] Storage unit 130 temporarily or permanently stores the programs and parameters used in the operation of base station 100, as well as various data.

[0110] (4) Processing unit 140

[0111] Processing unit 140 provides various functions of base station 100. Processing unit 140 includes a first communication processing unit 141 and a second communication processing unit 143. Note that processing unit 140 may also include other components besides these components. That is, processing unit 140 can perform operations other than those of these components. The specific operations of the first communication processing unit 141 and the second communication processing unit 143 will be described in detail below.

[0112] For example, processing unit 140 (first communication processing unit 141) communicates with terminal device (e.g., terminal device 300) via wireless communication unit 110. For example, processing unit 140 (second communication processing unit 143) communicates with other network nodes (e.g., base station 200) via network communication unit 120.

[0113] (5) Implementation Example

[0114] The wireless communication unit 110 can be implemented by an antenna or RF (radio frequency) circuit, and the antenna can be a directional antenna. The network communication unit 120 can be implemented by a network adapter or network interface card, etc. The storage unit 130 can be implemented by a memory (e.g., non-volatile memory and / or volatile memory) and / or a hard disk, etc. The processing unit 140 can be implemented by a BB (baseband) processor and / or other processors. The first communication processing unit 141 and the second communication processing unit 143 can be implemented by the same processor, or they can be implemented separately by different processors. The aforementioned memory (storage unit 130) can be included in such a processor (chip).

[0115] The base station 100 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform operations of the processing unit 140 (first communication processing unit 141 and second communication processing unit 143). The program may be a program for causing the one or more processors to perform operations of the processing unit 140 (first communication processing unit 141 and second communication processing unit 143).

[0116] <2.3. Structure of Base Station 200>

[0117] Next, refer to Figure 3 Here is an example illustrating the structure of the base station 200 in the first embodiment. Figure 3 This is a block diagram illustrating an example of the schematic structure of the base station 200 according to the first embodiment. (See reference...) Figure 3 The base station 200 includes a wireless communication unit 210, a network communication unit 220, a storage unit 230, and a processing unit 240.

[0118] (1) Wireless communication unit 210

[0119] The wireless communication unit 210 wirelessly transmits / receives signals. For example, the wireless communication unit 210 receives signals from the terminal device and transmits signals to the terminal device.

[0120] (2) Network communication unit 220

[0121] The network communication unit 220 receives signals from the backhaul and sends signals to the backhaul.

[0122] (3) Storage unit 230

[0123] Storage unit 230 temporarily or permanently stores the programs and parameters used in the operation of base station 200, as well as various data.

[0124] (4) Processing unit 240

[0125] Processing unit 240 provides various functions of base station 200. Processing unit 240 includes a first communication processing unit 241 and a second communication processing unit 243. Note that processing unit 240 may also include other components besides these components. That is, processing unit 240 can perform operations other than those of these components. The specific operations of the first communication processing unit 241 and the second communication processing unit 243 will be described in detail later.

[0126] For example, processing unit 240 (first communication processing unit 241) communicates with terminal device (e.g., terminal device 300) via wireless communication unit 210. For example, processing unit 240 (second communication processing unit 243) communicates with other network nodes (e.g., base station 100) via network communication unit 220.

[0127] (5) Implementation Example

[0128] The wireless communication unit 210 can be implemented by an antenna or radio frequency (RF) circuit, and the antenna can be a directional antenna. The network communication unit 220 can be implemented by a network adapter or network interface card, etc. The storage unit 230 can be implemented by a memory (e.g., non-volatile memory and / or volatile memory) and / or a hard disk, etc. The processing unit 240 can be implemented by a baseband (BB) processor and / or other processors. The first communication processing unit 241 and the second communication processing unit 243 can be implemented by the same processor, or they can be implemented separately by different processors. The aforementioned memory (storage unit 230) can be included in such a processor (chip).

[0129] The base station 200 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform operations of the processing unit 240 (first communication processing unit 241 and second communication processing unit 243). The program may be a program for causing the one or more processors to execute the operations of the processing unit 240 (first communication processing unit 241 and second communication processing unit 243).

[0130] <2.4. Structure of Terminal Equipment 300>

[0131] Next, refer to Figure 4 Here is an example illustrating the structure of the terminal device 300 in the first embodiment. Figure 4 This is a block diagram illustrating an example of the schematic structure of the terminal device 300 according to the first embodiment. (See reference) Figure 4 The terminal device 300 includes a wireless communication unit 310, a storage unit 320, and a processing unit 330.

[0132] (1) Wireless communication unit 310

[0133] The wireless communication unit 310 wirelessly transmits / receives signals. For example, the wireless communication unit 310 receives signals from a base station and transmits signals to the base station.

[0134] (2) Storage unit 320

[0135] Storage unit 320 temporarily or permanently stores the programs and parameters used in the operation of terminal device 300, as well as various data.

[0136] (3) Processing unit 330

[0137] The processing unit 330 provides various functions of the terminal device 300. The processing unit 330 includes a receiving processing unit 331 and a transmitting processing unit 333. Note that the processing unit 330 may also include other components besides these. That is, the processing unit 330 can perform operations other than those of these components. The specific operations of the receiving processing unit 331 and the transmitting processing unit 333 will be described in detail below.

[0138] For example, the processing unit 330 communicates with a base station (e.g., base station 100 and / or base station 200) via the wireless communication unit 310.

[0139] (4) Implementation Example

[0140] The wireless communication unit 310 can be implemented using an antenna or radio frequency (RF) circuitry, etc. The storage unit 320 can be implemented using a memory (e.g., non-volatile memory and / or volatile memory) and / or a hard disk, etc. The processing unit 330 can be implemented using a baseband (BB) processor and / or other processors. The receiving processing unit 331 and the transmitting processing unit 333 can be implemented using the same processor, or they can be implemented separately using different processors. The aforementioned memory (storage unit 320) can be included within such a processor (chip).

[0141] Terminal device 300 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform the operations of processing unit 330 (receiving processing unit 331 and transmitting processing unit 333). The program may be a program for causing one or more processors to perform the operations of processing unit 330 (receiving processing unit 331 and transmitting processing unit 333).

[0142] <2.5. Technical Features>

[0143] Next, refer to Figures 5-8 The technical features of the first embodiment will be explained below.

[0144] In the first embodiment, base station 100 (first communication processing unit 141) uses beamforming to transmit a reference signal. Terminal device 300 (receiving processing unit 331) receives the reference signal. For example, base station 100 is a base station located around terminal device 300, and the serving base station of terminal device 300 is base station 200.

[0145] In addition, the terminal device 300 (transmission processing unit 333) transmits the first beam-related information, which is used as information by the base station 100, to the base station 200, and the base station 200 (first communication processing unit 241) receives the first beam-related information from the terminal device 300.

[0146] Furthermore, the terminal device 300 is switched from base station 200 (source base station) to base station 100 (target base station). Base station 200 (second communication processing unit 243) sends a switching message (e.g., a switching request message) including second beam-related information corresponding to the first beam-related information to base station 100, and base station 100 (second communication processing unit 143) receives the switching message from base station 200.

[0147] Specifically, in the first embodiment, the base station 100 (first communication processing unit 141) receives the access signal of the terminal device 300 based on the second beam-related information.

[0148] (1) Transmission of reference signal

[0149] - Multiple beams

[0150] For example, base station 100 (first communication processing unit 141) uses multiple beams to transmit reference signals. These multiple beams can be referred to as the beams used by base station 100 to transmit signals (or the beams formed by base station 100 for transmitting signals). A beam is a beam pointing in different directions. Here, a beam means a directional beam, and is formed, for example, by multiplying a signal by a beamforming weight set and transmitting the signal obtained through this multiplication using a directional antenna. Reference will be made below. Figure 5 To illustrate specific examples of multiple beams.

[0151] Figure 5 This is an illustrative diagram illustrating an example of multiple beams used to transmit a reference signal. (Reference) Figure 5 The diagram illustrates base station 100, cell 10, and sixteen beams 11 (beams 11A to 11P). For example, base station 100 transmits reference signals using the sixteen beams 11 in this manner. As an example, each of these beams is identified by a beam index (or weight index). For example, beam 11A is identified by index #0, and beam 11J is identified by index #9.

[0152] - Wireless Resources

[0153] For example, base station 100 (first communication processing unit 141) uses different wireless resources for each beam to transmit reference signals through multiple beams.

[0154] As a first example, wireless resources are time resources. That is, base station 100 uses different time resources for each beam to transmit reference signals through multiple beams.

[0155] Figure 6 This is an illustrative diagram illustrating an example of the radio resources (time resources) used to transmit a reference signal. Reference Figure 6 The diagram illustrates sixteen time slots (slots #0 to #15) arranged in the time direction. In this example, during the beam search period 30 comprising the sixteen time slots, sixteen beams are used to transmit a reference signal. For example, in time slot #0, beam #0 (beam 11A) is used to transmit the reference signal, and in time slot #1, beam #1 (beam 11B) is used to transmit the reference signal. Similarly, in time slot #9, beam #9 (beam 11J) is used to transmit the reference signal. In this example, the time slots for transmitting the reference signal using beams are continuous, but the time slots do not need to be continuous and can be discrete. Note that the time slots here can be referred to as subframes, or simply gaps.

[0156] As a second example, the wireless resources can be frequency resources. That is, base station 100 can use different frequency resources for each beam to transmit reference signals through multiple beams. For example, base station 100 can transmit reference signals using beam #0 (beam 11A) in a first frequency band (e.g., a frequency band with a width of more than one resource block) within the frequency band, and transmit reference signals using beam #1 (beam 11B) in a second frequency band of the same band. Optionally, base station 100 can use a first carrier (e.g., more than one subcarrier) in a block frequency band (e.g., a frequency band with a resource block width) included in the frequency band to transmit reference signals through beam #0 (beam 11A), and use a second carrier in the block frequency band to transmit reference signals through beam #1 (beam 11B).

[0157] As a third example, the radio resources can be time-frequency resources. That is, base station 100 can use different time-frequency resources for each beam to transmit reference signals through multiple beams. For example, base station 100 can use a first time-frequency resource (e.g., more than one resource element) to transmit reference signals through beam #0 (beam 11A) and use a second time-frequency resource to transmit reference signals through beam #1 (beam 11B).

[0158] As a result, even when the base station 100 transmits a reference signal that is common to the beam, the terminal device can identify the beam used to transmit the reference signal.

[0159] The relationship between beams and wireless resources can be determined statically (e.g., in a standard) or can be configured by the operator or network.

[0160] Note that instead of using different wireless resources for each beam, base station 100 (first communication processing unit 141) can transmit reference signals for each beam. This enables terminal devices to identify the beam used to transmit the reference signal.

[0161] (2) Measurement Report

[0162] For example, terminal device 300 (receiving and processing unit 331) uses beamforming to measure the reference signal transmitted by base station 100.

[0163] For example, terminal device 300 (transmission processing unit 333) sends a measurement report to base station 200. The measurement report includes measurement results of the reference signal transmitted by base station 100 using beamforming. In particular, the measurement report also includes the first beam-related information mentioned above.

[0164] More specifically, for example, terminal device 300 measures the reference signals transmitted by each beam to select the beam with the best measurement results (e.g., highest received power or received quality). In other words, terminal device 300 selects preferred beamforming weights. Then, terminal device 300 sends a measurement report to base station 200, including first beam-related information associated with the selected beam and the best measurement results.

[0165] Figure 7 This is an explanatory diagram illustrating an example of a measurement report from terminal device 300. (Reference) Figure 7 The diagram illustrates base station 100 and terminal device 300. For example, terminal device 300 performs measurements on reference signals transmitted via beams to select beam #9 (beam 11J) with the best measurement results. Then, terminal device 300 sends a measurement report to base station 200, including first beam-related information (e.g., beam index / weight index #9) related to beam #9 (beam 11J) and the best measurement results.

[0166] As a result, for example, base station 200 can obtain information related to the first beam of base station 100 through the measurement report.

[0167] (3) Switching messages

[0168] As described above, base station 200 (source base station) sends a handover message including information related to the second beam to base station 100 (target base station). This handover message can be sent directly from base station 200 to base station 100 (e.g., in the case of X2 handover), or it can be sent from base station 200 to base station 100 via the core network (e.g., in the case of S1 handover).

[0169] For example, the handover message is a handover request message. The following description of the first embodiment will assume that the handover message is a handover request message. However, the handover message used in the first embodiment is not limited to a handover request message, but can be other messages sent from the source base station to the target base station during the handover process.

[0170] (4) Beam-related information

[0171] - Relationship between first beam related information and second beam related information

[0172] As mentioned above, the second beam-related information corresponds to the first beam-related information.

[0173] For example, the second beam-related information is the same as the first beam-related information. That is, base station 200 includes the same second beam-related information as the first beam-related information received from terminal device 300 in the handover request message, and sends the handover request message to base station 100.

[0174] Optionally, the second beam-related information can be different from the first beam-related information. For example, base station 200 can convert the first beam-related information into second beam-related information to send a handover request message including the second beam-related information to base station 100.

[0175] - Examples of beam-related information

[0176] Beam-related information (first beam-related information and second beam-related information) is information related to the beam. Since beamforming weights (beamforming weight sets) are used to form beams, there can be a one-to-one correspondence between beams and beamforming weight sets. Therefore, beam-related information can also be referred to as information related to beamforming weights (e.g., weight-related information).

[0177] Beam-related information is information used by base station 100. For example, beam-related information is information related to the beam of base station 100 (the beam used by base station 100 to transmit signals).

[0178] For example, beam-related information is information relating to one of a plurality of beams. Specifically, for example, beam-related information is information indicating one of a plurality of beams; in other words, information enabling the identification of one of a plurality of beams (e.g., beam identification information). As an example, beam-related information is a beam index. Alternatively, beam-related information can be information indicating one of a plurality of beamforming weight sets; in other words, information enabling the identification of one of a plurality of sets (e.g., weight identification information). As an example, beam-related information can be a weight index. Since beamforming weight sets are used to form beams, beams can have a one-to-one correspondence with beamforming weight sets. Therefore, beam-related information can be information indicating one of a plurality of beams (beam index), and can be the aforementioned information indicating one of a plurality of sets (weight index). That is, beam index and weight index, although named differently, can be the same index. Of course, beam-related information can be information with other names (beam ID, weight ID, beamforming index, or beamforming ID, etc.) that enables the identification of beams or beamforming weight sets.

[0179] (5) Reception of access signals

[0180] Specifically, in the first embodiment, the base station 100 (first communication processing unit 141) receives the access signal of the terminal device 300 based on the second beam-related information.

[0181] For example, base station 100 (first communication processing unit 141) uses a beamforming weight set corresponding to the second beam-related information to receive the access signal. Specifically, for example, the second beam-related information is a beam index or a weight index, and base station 100 identifies the beamforming weight set based on the beam index or weight index. Then, base station 100 uses the beamforming weight set to receive the access signal. That is, base station 100 performs uplink beamforming processing by multiplying the access signal by the aforementioned beamforming weight set.

[0182] The access signal can be an uplink signal used in initial access for transitioning from an idle state (e.g., RRC_Idle) to an active state or a connected state (e.g., RRC_Connected), or in access to the target cell during handover. Optionally, the access signal can be an uplink signal used in the reconstruction of a radio connection (RRC connection reconstruction) for the restoration of radio connectivity. The uplink signal can be a random access signal (e.g., a random access preamble), a control signal transmitted on an uplink data channel (e.g., PUSCH (Physical Uplink Shared Channel)), or a control signal transmitted on an uplink control channel (e.g., PUCCH (Physical Uplink Control Channel)). In System 1 of the first embodiment, unlike the technology disclosed in patent document (Japanese Patent Publication No. 2014-531852), the terminal device 300 does not communicate with the base station 100 in advance (through ranging and its response), but instead begins communication with the base station 100 using the access signal. Therefore, successful reception of the access signal is crucial.

[0183] Therefore, using second-beam-related information to receive the access signal ensures, for example, compensation for signal propagation loss, thus increasing the likelihood of successful access signal reception. This can further increase the probability of successful handover.

[0184] Note that, for example, the beamforming weight set used for the uplink is the same as the beamforming weight set used for the downlink. Alternatively, the beamforming weight set used for the uplink may be different from the beamforming weight set used for the downlink.

[0185] (6) Processing flow

[0186] Reference Figure 8 An example illustrating the processing according to the first embodiment will be given. Figure 8 This is a sequence diagram illustrating an example of a schematic flow of the process according to the first embodiment.

[0187] Terminal device 300 uses beamforming to measure the reference signal transmitted by base station 100 in order to select preferred beamforming weights. Then, terminal device 300 sends a measurement report, including a weight index indicating the preferred beamforming weights, to base station 200 (serving base station) (S401). The measurement report includes the measurement results of the reference signal.

[0188] Then, it is decided that the terminal device 300 will switch from the base station 200 (source base station) to the base station 100 (target base station), and the base station 200 will send a handover request message including a weight index indicating the preferred beamforming weight to the base station 100 (S403).

[0189] Base station 100 obtains the weight index included in the handover request message and sends a handover request acknowledgment message (S405) to base station 200, which includes a handover command message of the RRC layer corresponding to the handover indication.

[0190] Base station 200 sends an RRC signal (e.g., RRC Connection Reconfiguration message) including a handover command message to terminal device 300 (S407).

[0191] Terminal device 300 sends the access signal to base station 100 (S409). Base station 100 receives the access signal based on the weight index. That is, base station 100 uses the beamforming weight indicated by the weight index to receive the access signal.

[0192] Note that the above processing flow example is merely illustrative, and of course, transmission / reception other than the transmission / reception in steps S401 to S409 described above can be performed in the first embodiment.

[0193] (7) The meaning of “send”

[0194] Here, "transmitting" means, for example, performing transmission processing at at least one of multiple protocol layers, but does not mean outputting a signal via wired or wireless means. Similarly, "receiving" means, for example, performing reception processing at at least one of multiple protocol layers. As an example, multiple protocol layers include the physical layer, MAC (Media Access Control) layer, RLC (Radio Link Control) layer, PDCP (Packet Data Convergence Protocol) layer, and RRCS (Radio Resource Control) layer. As another example, multiple protocol layers include the physical layer, MAC layer, IP (Internet Protocol) layer, and transport layer.

[0195] Furthermore, "sending X to Y" here is not limited to sending X directly to Y, but also includes sending X indirectly to Y (i.e., sending X to another node, and then sending X to Y through the transmission of that other node). Similarly, "receiving X from Y" here is not limited to receiving X directly from Y, but also includes receiving X indirectly from Y (i.e., receiving X sent by Y through the transmission of another node).

[0196] <2.6. Variations>

[0197] Next, refer to Figures 9-11 Let us now describe a variation of the first embodiment.

[0198] (1) First variant

[0199] -Resource Information

[0200] In a first variation of the first embodiment, for example, base station 100 (second communication processing unit 143) sends resource information indicating radio resources for transmitting access signals to base station 200, and base station 200 (second communication processing unit 243) receives the resource information.

[0201] Then, the base station 200 (first communication processing unit 241) sends the resource information to the terminal device 300, and the terminal device 300 (receiving processing unit 331) receives the resource information.

[0202] Subsequently, the terminal device 300 (transmission processing unit 333) transmits the access signal to the base station 100 based on the resource information. That is, the terminal device 300 (transmission processing unit 333) uses the radio resources indicated by the resource information to transmit the access signal to the base station 100. The base station 100 (based on the aforementioned second beam-related information) receives the access signal transmitted using the radio resources.

[0203] As a result, for example, base station 100 can more easily receive access signals from terminal device 300.

[0204] Resource information can be referred to as dedicated RACH (Random Access Channel) resource information.

[0205] - Wireless Resources

[0206] For example, the aforementioned wireless resources are the wireless resources used by the beam or beamforming weight set corresponding to the second beam-related information.

[0207] More specifically, for example, access to radio resources is prepared for each beam or for each beamforming weight set. For example, second beam-related information indicates the beam or beamforming weight set, and the radio resources indicated by the resource information are the radio resources used by that beam or that beamforming weight set.

[0208] Figure 9 This is an illustrative diagram used to illustrate an example of the wireless resources indicated by the resource information. (Reference) Figure 9 The diagram illustrates the N time slots included in each radio frame. In this example, access radio resources are prepared in each time slot. For example, time slot #0 is the access radio resource for beam #0. In this case, in time slot #0, base station 100 uses the beamforming weight set identified by beam index (or weight index) #0 to receive the access signal. For example, time slot #N-1 is the access radio resource for beam #15. In this case, in time slot #N-1, base station 100 uses the beamforming weight set identified by beam index (or weight index) #15 to receive the access signal.

[0209] As a result, for example, base station 100 can more easily receive access signals from terminal device 300. This is because, when receiving access signals, base station 100 does not need to use various beamforming weight sets, but only a specific beamforming weight set.

[0210] -Retransmission cycle information

[0211] For example, base station 100 (second communication processing unit 143) sends retransmission period information indicating the retransmission period of the access signal together with resource information to base station 200, and base station 200 (second communication processing unit 243) receives the retransmission period information.

[0212] Then, the base station 200 (first communication processing unit 241) sends the retransmission cycle information to the terminal device 300, and the terminal device 300 (receiving processing unit 331) receives the retransmission cycle information.

[0213] Subsequently, the terminal device 300 (transmission processing unit 333) retransmits the access signal to the base station 100 based on the retransmission period information. In other words, the terminal device 300 (transmission processing unit 333) retransmits the access signal to the base station 100 according to the retransmission period indicated by the retransmission period information.

[0214] As a result, for example, base station 100 can also more easily receive retransmitted access signals.

[0215] The retransmission period information can be referred to as RACH (Random Access Channel) retransmission period information.

[0216] -information

[0217] For example, base station 100 (second communication processing unit 143) sends a response message to the aforementioned handover request message to base station 200, and base station 200 (second communication processing unit 243) receives the response message. This response message can be sent directly from base station 100 to base station 200 (e.g., in the case of X2 handover), or it can be sent from base station 100 to base station 200 via the core network (e.g., in the case of S1 handover). Specifically, the response message includes resource information and retransmission period information. For example, the response message is a handover request confirmation message. Furthermore, for example, the handover request confirmation message includes an RRC container, and the RRC container includes a handover command message. Furthermore, for example, the handover command message includes an RRC connection reconfiguration message, and the RRC connection reconfiguration message includes resource information and retransmission period information. Of course, the first embodiment is not limited to this example, and the response message can include resource information and retransmission period information in different ways.

[0218] For example, base station 200 (first communication processing unit 241) sends (transmits) a handover command message (included in the response message) to terminal device 300, and terminal device 300 (receiving processing unit 331) receives the handover command message. As described above, the handover command message includes resource information and retransmission period information.

[0219] -Processing flow

[0220] Figure 10 This is a sequence diagram illustrating an example of a schematic flow for explaining the processing of a first variation of the first embodiment. Figure 10 The explanation and examples of steps S421 and S423 shown Figure 8 The descriptions of steps S401 and S403 are the same. Therefore, repeated descriptions will be omitted here, and only steps S425, S427, and S429 will be described.

[0221] Base station 100 obtains the weight index contained in the handover request message. Then, base station 100 generates dedicated RACH resource information indicating the radio resources used by the beamforming weight set represented by the weight index. Afterwards, base station 100 sends a handover command message including the dedicated RACH resource information to base station 200 in a handover request confirmation message (S425). The handover command message may also include RACH retransmission period information.

[0222] Base station 200 transmits the handover command message to terminal device 300 (S427).

[0223] Terminal device 300 uses the radio resources indicated by the dedicated RACH resource information to transmit the access signal to base station 100 (S429). Based on the weight index, base station 100 receives the access signal transmitted using the radio resources. That is, base station 100 uses the beamforming weight set indicated by the weight index to receive the access signal transmitted using the radio resources (the radio resources used by the beamforming weight set). Incidentally, if retransmission is required, terminal device 300 retransmits the access signal to base station 100 according to the retransmission period indicated by the dedicated RACH retransmission period information.

[0224] Note that the above processing flow example is merely illustrative, and of course, in the first variation of the first embodiment, transmission / reception other than the transmission / reception in steps S421 to S429 above can be performed.

[0225] -Alternative methods

[0226] In the example above, base station 100 sends resource information indicating radio resources for transmitting access signals to base station 200, and base station 200 receives the resource information, but the first variation is not limited to this example.

[0227] Instead of base station 100 sending resource information to base station 200, base station 200 (first communication processing unit 241) can generate resource information. In this case, base station 200 can receive in advance from base station 100 the information required to generate resource information (e.g., information indicating the radio resources of each beam).

[0228] As a result, for example, the amount of information transmitted / received between base station 100 and base station 200 can be reduced.

[0229] (2) Second variation

[0230] In a second variation of the first embodiment, for example, base station 100 (second communication processing unit 143) sends beamforming configuration information related to the beamforming configuration of base station 100 to base station 200. Then, base station 200 (second communication processing unit 243) receives the beamforming configuration information.

[0231] In addition, the base station 200 (first communication processing unit 241) sends beamforming configuration information to the terminal device 300, and the terminal device (receiving processing unit 331) receives the beamforming configuration information.

[0232] Then, based on the beamforming configuration information, the terminal device 300 (receiving and processing unit 331) receives the reference signal transmitted by the base station 100 using beamforming. For example, the terminal device 300 (receiving and processing unit 331) measures the reference signal based on the beamforming configuration information.

[0233] As a result, for example, a beamforming configuration suitable for a base station or cell can be used, and the terminal device 300 can perform reception / measurement corresponding to that configuration.

[0234] - Configuration Information

[0235] For example, beamforming configuration information includes beam count information indicating the number of beams. Figure 5 In the example, the beam number information indicates 16 as the number of beams. As a result, the number of beams can be used corresponding to the characteristics of the cell (e.g., size).

[0236] For example, beamforming configuration information includes beam resource information indicating the radio resources of each beam used to transmit reference signals. For example, as in the reference... Figure 6The radio resources are the time resources of each beam. In this case, for example, beam resource information includes the period and offset in the time direction. Alternatively, the radio resources can be the frequency resources of each beam. In this case, beam resource information can include the period and offset in the frequency direction. Alternatively, the radio resources can be the time-frequency resources of each beam. In this case, beam resource information can be information indicating the mode of the radio resources. This allows, for example, more flexibility in setting the radio resources to be used for transmitting a reference signal using beamforming.

[0237] -information

[0238] For example, when setting up the interface between base station 100 and base station 200, base station 100 (second communication processing unit 143) sends beamforming configuration information to base station 200. Then, base station 200 (second communication processing unit 243) receives the beamforming configuration information.

[0239] Specifically, for example, base station 100 (second communication processing unit 143) sends an X2 SETUP REQUEST message or an X2 SETUP RESPONSE message to base station 200. Then, base station 200 (second communication processing unit 243) receives the X2 SETUP REQUEST message or X2 SETUP RESPONSE message. In particular, the X2 SETUP REQUEST message or X2 SETUP RESPONSE message includes beamforming configuration information.

[0240] For example, base station 200 (first communication processing unit 241) sends a measurement configuration to terminal device 300, and terminal device 300 (receiving processing unit 331) receives the measurement configuration. In particular, the measurement configuration includes beamforming configuration information.

[0241] - Processing flow

[0242] Figure 11 This is a sequence diagram illustrating an example of a schematic flow for explaining the processing of a second variation of the first embodiment. Figure 11 The explanation and examples of steps S449 to S455 shown Figure 8 The explanations for steps S403 to S409 are the same. Therefore, repeated explanations will be omitted here, and only steps S441 to S447 will be explained.

[0243] Base station 200 sends an X2 configuration request message to base station 100 (S441), and in response, base station 100 sends an X2 configuration response message to base station 200 (S443). The X2 configuration response message includes beamforming configuration information related to the beamforming configuration of base station 100.

[0244] In addition, base station 200 sends measurement configuration, including beamforming configuration information, to terminal device 300 (S445).

[0245] Based on the beamforming configuration information, the terminal device 300 measures the reference signal transmitted by the base station 100 using beamforming and selects a preferred beamforming weight. Then, the terminal device 300 sends a measurement report, including a weight index indicating the preferred beamforming weight, to the base station 200 (serving base station) (S447). The measurement report includes the measurement results of the reference signal.

[0246] (3) Third variation

[0247] When the handover of terminal device 300 fails and terminal device 300 attempts to reconnect to the same target cell, similar to the example described above in the first embodiment, base station 100 (first communication processing unit 141) can also receive the access signal of terminal device 300 based on the second beam-related information.

[0248] Furthermore, when the handover of the terminal device 300 fails, or when the terminal device 300 attempts to reconnect to the same target cell, the terminal device 300 (transmission processing unit 333) can also send the access signal to the base station 100 based on resource information, similar to the first variation of the first embodiment.

[0249] The various modifications of the first embodiment have been described above. Note that two or more modifications from the first to the third embodiment can be combined. That is, a combination of the technical features of two or more modifications from the first to the third embodiment can be introduced.

[0250] <<3. Second Embodiment>>

[0251] Next, refer to Figures 12-16 The second embodiment of the present invention will now be described. The first embodiment described above is a specific embodiment, but the second embodiment is a more generalized embodiment.

[0252] <3.1. System Structure>

[0253] Reference Figure 12 Here is an example illustrating the structure of system 2 according to the second embodiment. Figure 12 This is an explanatory diagram illustrating an example of the schematic structure of system 2 according to the second embodiment. (See reference) Figure 12 System 2 includes base station 500, base station 600 and terminal equipment 700.

[0254] For example, System 2 can be a system compliant with 3GPP standards. More specifically, System 2 can be, for example, a system compliant with fifth-generation (5G) standards.

[0255] For example, the descriptions of base station 500, base station 600, and terminal device 700 are the same as those of base station 100, base station 200, and terminal device 300 in the first embodiment. Therefore, repeated descriptions will be omitted here.

[0256] <3.2. Structure of Base Station 500>

[0257] Next, refer to Figure 13 Here is an example illustrating the structure of the base station 500 in the second embodiment. Figure 13 This is a block diagram illustrating an example of the schematic structure of the base station 500 according to the second embodiment. (See reference) Figure 13 The base station 500 includes a first communication processing unit 510 and a second communication processing unit 520.

[0258] The specific operations of the first communication processing unit 510 and the second communication processing unit 520 will be described later.

[0259] The first communication processing unit 510 and the second communication processing unit 520 may be implemented by a baseband (BB) processor and / or other processors. The first communication processing unit 510 and the second communication processing unit 520 may be implemented by the same processor, or they may be implemented by different processors separately.

[0260] The base station 500 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform operations on the first communication processing unit 510 and the second communication processing unit 520. The program may be a program for causing the one or more processors to execute the operations of the first communication processing unit 510 and the second communication processing unit 520.

[0261] <3.3. Structure of Base Station 600>

[0262] Next, refer to Figure 14 Here is an example illustrating the structure of the base station 600 in the second embodiment. Figure 14 This is a block diagram illustrating an example of the schematic structure of the base station 600 according to the second embodiment. (See reference) Figure 14 The base station 600 includes a first communication processing unit 610 and a second communication processing unit 620.

[0263] The specific operations of the first communication processing unit 610 and the second communication processing unit 620 will be described later.

[0264] The first communication processing unit 610 and the second communication processing unit 620 may be implemented by a baseband (BB) processor and / or other processors. The first communication processing unit 610 and the second communication processing unit 620 may be implemented by the same processor, or they may be implemented by different processors separately.

[0265] Base station 600 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform operations of the first communication processing unit 610 and the second communication processing unit 620. The program may be a program for causing the one or more processors to execute the operations of the first communication processing unit 610 and the second communication processing unit 620.

[0266] <3.4. Structure of Terminal Equipment 700>

[0267] Next, refer to Figure 15 Here is an example illustrating the structure of the terminal device 700 in the second embodiment. Figure 15 This is a block diagram illustrating an example of the schematic structure of the terminal device 700 according to the second embodiment. (See reference) Figure 15 The terminal device 700 includes a receiving processing unit 710 and a sending processing unit 720.

[0268] The specific operations of the receiving processing unit 710 and the transmitting processing unit 720 will be explained later.

[0269] The receiving processing unit 710 and the transmitting processing unit 720 can be implemented by a baseband (BB) processor and / or other processors. The receiving processing unit 710 and the transmitting processing unit 720 can be implemented by the same processor, or they can be implemented by different processors separately.

[0270] Terminal device 700 may include a memory for storing a program and one or more processors capable of executing the program. The one or more processors may perform operations of the receiving processing unit 710 and the transmitting processing unit 720. The program may be a program for causing the one or more processors to execute the operations of the receiving processing unit 710 and the transmitting processing unit 720.

[0271] <3.5. Technical Features>

[0272] Next, refer to Figure 16 The technical features of the second embodiment will be explained below.

[0273] In the second embodiment, the base station 500 (first communication processing unit 510) uses beamforming to transmit a reference signal. The terminal device 700 (receiving processing unit 710) receives the reference signal.

[0274] In addition, the terminal device 700 (transmission processing unit 720) transmits the first beam-related information, which is used as information by the base station 500, to the base station 600, and the base station 600 (first communication processing unit 610) receives the first beam-related information.

[0275] Furthermore, the terminal device 700 is switched from base station 600 (source base station) to base station 500 (target base station). Base station 600 (second communication processing unit 620) sends a switching message (e.g., a switching request message) including second beam information corresponding to the first beam information to base station 500, and base station 500 (second communication processing unit 520) receives the switching message.

[0276] Specifically, in the second embodiment, the base station 500 (first communication processing unit 510) receives the access signal of the terminal device 700 based on the second beam-related information.

[0277] (1) Transmission of reference signals, measurement reports, handover messages, beam-related information, reception of access signals, and the meaning of "transmission".

[0278] For example, the descriptions of reference signal transmission, measurement reports, handover messages, beam-related information, access signal reception, and the meaning of "transmission" in the second embodiment are the same as those in the first embodiment. Therefore, repeated descriptions will be omitted here, and only examples of illustrative processing flows will be described.

[0279] (2) Processing flow

[0280] Figure 16 This is a sequence diagram illustrating an example of a schematic flow of the processing according to the second embodiment.

[0281] Terminal device 700 sends a first beam-related information, which is used as information by base station 500, to base station 600, and base station 600 receives the first beam-related information (S801).

[0282] Base station 600 sends a handover message (e.g., a handover request message) that includes second beam information corresponding to the first beam information to base station 500, and base station 500 receives the handover message (S803).

[0283] Base station 500 receives access signal from terminal device 700 based on second beam-related information (S805).

[0284] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. Those skilled in the art will understand that the above embodiments are merely examples, and various changes and modifications can be made without departing from the scope and spirit of the present invention.

[0285] For example, the steps in the process described in the specification do not necessarily have to be performed in a time-series manner in the order described as a sequence diagram. For example, the steps in the process may be executed in a different order than that described as a sequence diagram, or they may be executed in parallel. Furthermore, a portion of the steps in the process may be deleted, and more steps may be added to the process.

[0286] Furthermore, devices or modules thereof (e.g., baseband processors or other chips) including the constituent elements of a base station described in the specification (e.g., a first communication processing unit and / or a second communication processing unit) can be provided. Similarly, modules (e.g., baseband processors or other chips) including the constituent elements of a terminal device described in the specification (e.g., a receiving processing unit and / or a transmitting processing unit) can be provided. Furthermore, methods for processing each constituent element can be provided, and programs for causing a processor to execute the processing of the constituent elements can be provided. Additionally, recording media (computer-readable non-transitory recording media) for recording the respective programs can be provided. Of course, these devices, modules, methods, programs, and recording media are also included in this invention.

[0287] Some or all of the above embodiments may be described as supplementary descriptions below, but are not limited to the following supplementary descriptions.

[0288] (Supplementary Note 1)

[0289] An apparatus comprising:

[0290] A first communication processing unit is configured to transmit a reference signal using beamforming; and

[0291] The second communication processing unit is configured to receive handover messages from the source base station of the terminal device during the handover.

[0292] The switching message includes beam-related information and...

[0293] The first communication processing unit is configured to receive the access signal of the terminal device based on the beam-related information.

[0294] (Supplementary Note 2)

[0295] According to the device described in Supplementary Note 1, the first communication processing unit is configured to receive the access signal using a beamforming weight set corresponding to the beam-related information.

[0296] (Supplementary Explanation 3)

[0297] According to the device described in Supplementary Note 1 or 2, the access signal is an uplink signal in the random access of the terminal device.

[0298] (Supplementary Note 4)

[0299] According to any one of Supplementary Descriptions 1 to 3, the second communication processing unit is configured to send resource information indicating radio resources for transmitting the access signal to the source base station.

[0300] (Supplementary Note 5)

[0301] According to the device described in Supplementary Note 4, the wireless resources are wireless resources used by the beam or beamforming weight set corresponding to the beam-related information.

[0302] (Supplementary Note 6)

[0303] According to the device described in Supplementary Note 4 or 5, wherein...

[0304] The second communication processing unit is configured to send a response message to the handover message to the source base station, and

[0305] The response message includes the resource information.

[0306] (Supplementary Note 7)

[0307] According to any one of Supplementary Descriptions 4 to 6, the second communication processing unit is configured to send retransmission period information indicating the retransmission period of the access signal together with the resource information to the source base station.

[0308] (Supplementary Note 8)

[0309] According to any one of Supplementary Explanations 4 to 7, the resource information is information sent from the source base station to the terminal device.

[0310] (Supplementary Note 9)

[0311] According to any one of Supplementary Descriptions 1 to 8, the first communication processing unit is configured to transmit a reference signal via a plurality of beams.

[0312] (Supplementary Note 10)

[0313] According to the device described in Supplementary Note 9, the first communication processing unit is configured to transmit reference signals through the plurality of beams using different wireless resources for each beam.

[0314] (Supplementary Note 11)

[0315] According to the device described in Supplementary Note 10, the wireless resources are frequency resources, time resources, or time-frequency resources.

[0316] (Supplementary Note 12)

[0317] According to any one of Supplementary Notes 1 to 11, the beam-related information is information relating to one of a plurality of beams.

[0318] (Supplementary Note 13)

[0319] According to the device described in Supplementary Note 12, the beam-related information is information indicating one of the plurality of beams.

[0320] (Supplementary Note 14)

[0321] According to the device described in Supplementary Note 12 or 13, the beam-related information is information indicating one of a plurality of beamforming weight sets.

[0322] (Supplementary Note 15)

[0323] According to any one of Supplementary Notes 1 to 14, the beam-related information corresponds to the beam-related information transmitted from the terminal device to the source base station.

[0324] (Supplementary Note 16)

[0325] According to any one of Supplementary Descriptions 1 to 15, the second communication processing unit is configured to send beamforming configuration information related to the beamforming configuration to the source base station.

[0326] (Supplementary Note 17)

[0327] According to the device described in Supplementary Note 16, the beamforming configuration information includes information indicating the number of beams and information indicating the radio resources used by each beam for transmitting reference signals.

[0328] (Supplementary Note 18)

[0329] According to the device described in Supplementary Note 16 or 17, the beamforming configuration information is information to be sent from the source base station to the terminal device.

[0330] (Supplementary Note 19)

[0331] According to any one of Supplementary Descriptions 1 to 18, the device is a base station, one or more of the plurality of devices included in a base station, or a module used by one of the plurality of devices.

[0332] (Supplementary Note 20)

[0333] An apparatus comprising:

[0334] A first communication processing unit is configured to receive, from a terminal device, first beam-related information, which is information used by a base station to transmit reference signals using beamforming; and

[0335] The second communication processing unit is configured to send a switching message, including second beam-related information corresponding to the first beam-related information, to the base station.

[0336] The second beam-related information is information that the base station uses to receive the access signal from the terminal device.

[0337] (Supplementary Note 21)

[0338] According to the device described in Supplementary Description 20, the first communication processing unit is configured to send resource information indicating wireless resources for transmitting the access signal to the terminal device.

[0339] (Supplementary Note 22)

[0340] According to the device described in Supplementary Description 21, the first communication processing unit is configured to send retransmission period information indicating the retransmission period of the access signal together with the resource information to the terminal device.

[0341] (Supplementary Note 23)

[0342] According to the device described in supplementary description 21 or 22, wherein,

[0343] The first communication processing unit is configured to send a handover command message to the terminal device, and

[0344] The switching command message includes the resource information.

[0345] (Supplementary Note 24)

[0346] According to any one of Supplementary Descriptions 21 to 23, the device wherein the second communication processing unit is configured to receive the resource information from the base station.

[0347] (Supplementary Note 25)

[0348] According to any one of Supplementary Notes 21 to 23, the device wherein the first communication processing unit is configured to generate the resource information.

[0349] (Supplementary Note 26)

[0350] According to any one of Supplementary Descriptions 20 to 25, the device wherein the second beam-related information is the same as the first beam-related information.

[0351] (Supplementary Note 27)

[0352] According to any one of Supplementary Descriptions 20 to 26, the device wherein the first beam-related information and the second beam-related information are information relating to one of a plurality of beams.

[0353] (Supplementary Note 28)

[0354] The device according to any one of Supplementary Descriptions 20 to 27, wherein,

[0355] The first communication processing unit is configured to receive a measurement report sent from the terminal device, and

[0356] The measurement report includes information related to the first beam.

[0357] (Supplementary Note 29)

[0358] The device according to any one of Supplementary Descriptions 20 to 28, wherein,

[0359] The second communication processing unit is configured to receive beamforming configuration information related to the beamforming configuration of the base station from the base station, and

[0360] The first communication processing unit is configured to send the beamforming configuration information to the terminal device.

[0361] (Supplementary Note 30)

[0362] According to the device described in Supplementary Note 29, wherein,

[0363] The first communication processing unit is configured to send measurement configuration to the terminal device, and

[0364] The measurement configuration includes the beamforming configuration information.

[0365] (Supplementary Note 31)

[0366] According to any one of Supplementary Descriptions 20 to 30, the device is a base station, one or more of the plurality of devices included in a base station, or a module used by one of the plurality of devices.

[0367] (Supplementary Note 32)

[0368] An apparatus comprising:

[0369] A receiving processing unit configured to receive a reference signal transmitted by a first base station using beamforming; and

[0370] The transmission processing unit is configured to transmit first beam-related information to the second base station, wherein the first beam-related information is information used by the first base station.

[0371] The first beam-related information corresponds to the second beam-related information used by the first base station to receive the access signal.

[0372] (Supplementary Explanation 33)

[0373] According to the device described in Supplementary Description 32, wherein...

[0374] The receiving and processing unit receives from the second base station resource information indicating radio resources used for transmitting access signals, and

[0375] The transmission processing unit is configured to send the access signal to the first base station based on the resource information.

[0376] (Supplementary Note 34)

[0377] According to the device described in Supplementary Description 33, wherein...

[0378] The receiving processing unit is configured to receive retransmission period information indicating the retransmission period of the access signal and the resource information together with the second base station, and the sending processing unit is configured to retransmit the access signal to the first base station based on the retransmission period information.

[0379] (Supplementary Note 35)

[0380] The device according to any one of Supplementary Descriptions 32 to 34, wherein,

[0381] The transmission processing unit is configured to send a measurement report to the second base station, and

[0382] The measurement report includes information related to the first beam.

[0383] (Supplementary Explanation 36)

[0384] According to the device described in Supplementary Note 35, the measurement report includes measurement results of a reference signal transmitted by the first base station using beamforming.

[0385] (Supplementary Note 37)

[0386] According to any one of Supplementary Descriptions 32 to 36, the device wherein,

[0387] The receiving and processing unit is configured to receive beamforming configuration information related to the beamforming configuration of the first base station from the second base station, and

[0388] The receiving and processing unit is configured to receive a reference signal transmitted by the first base station using beamforming, based on the beamforming configuration information.

[0389] (Supplementary Note 38)

[0390] The device according to any one of Supplementary Notes 32 to 37, wherein the device is a terminal device or a module used by a terminal device.

[0391] (Supplementary Note 39)

[0392] One method includes:

[0393] Beamforming is used to transmit reference signals;

[0394] The terminal device receives a handover message from the source base station, the handover message including beam-related information; and

[0395] The terminal device's access signal is received based on the beam-related information.

[0396] (Supplementary Note 40)

[0397] One method includes:

[0398] Receive, from the terminal device, first beam-related information, which is information used by a base station for transmitting reference signals using beamforming; and

[0399] A switching message including second beam-related information corresponding to the first beam-related information is sent to the base station.

[0400] The second beam-related information is information that the base station uses to receive the access signal from the terminal device.

[0401] (Supplementary Note 41)

[0402] One method includes:

[0403] Receive the reference signal transmitted by the first base station using beamforming; and

[0404] The first beam-related information, which is information used by the first base station, is sent to the second base station.

[0405] The first beam-related information corresponds to the second beam-related information used by the first base station to receive the access signal.

[0406] (Supplementary Note 42)

[0407] A system comprising:

[0408] First base station;

[0409] Second base station; and

[0410] Terminal equipment,

[0411] The first base station uses beamforming to transmit reference signals.

[0412] The terminal device receives the reference signal and transmits a first beam-related information to the second base station, wherein the first beam-related information is information used by the first base station.

[0413] The second base station sends a handover message, including second beam-related information corresponding to the first beam-related information, to the first base station.

[0414] The first base station receives the access signal from the terminal device based on the second beam-related information.

[0415] (Supplementary Note 43)

[0416] A program used to cause the processor to execute:

[0417] Beamforming is used to transmit reference signals;

[0418] The terminal device receives a handover message from the source base station, the handover message including beam-related information; and

[0419] The terminal device's access signal is received based on the beam-related information.

[0420] (Supplementary Note 44)

[0421] A program used to cause the processor to execute:

[0422] Receive, from the terminal device, first beam-related information, which is information used by a base station for transmitting reference signals using beamforming; and

[0423] A switching message including second beam-related information corresponding to the first beam-related information is sent to the base station.

[0424] The second beam-related information is information that the base station uses to receive the access signal from the terminal device.

[0425] (Supplementary Note 45)

[0426] A program used to cause the processor to execute:

[0427] Receive the reference signal transmitted by the first base station using beamforming; and

[0428] The first beam-related information, which is information used by the first base station, is sent to the second base station.

[0429] The first beam-related information corresponds to the second beam-related information used by the first base station to receive the access signal.

[0430] (Supplementary Note 46)

[0431] A computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute:

[0432] Beamforming is used to transmit reference signals;

[0433] The terminal device receives a handover message from the source base station, the handover message including beam-related information; and

[0434] The terminal device's access signal is received based on the beam-related information.

[0435] (Supplementary Note 47)

[0436] A computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute:

[0437] Receive, from the terminal device, first beam-related information, which is information used by a base station for transmitting reference signals using beamforming; and

[0438] A switching message including second beam-related information corresponding to the first beam-related information is sent to the base station.

[0439] The second beam-related information is information that the base station uses to receive the access signal from the terminal device.

[0440] (Supplementary Note 48)

[0441] A computer-readable, non-transitory recording medium having a program recorded thereon for causing a processor to execute:

[0442] Receive the reference signal transmitted by the first base station using beamforming; and

[0443] The first beam-related information, which is information used by the first base station, is sent to the second base station.

[0444] The first beam-related information corresponds to the second beam-related information used by the first base station to receive the access signal.

[0445] This application is based on and claims priority to Japanese Patent Application 2016-152618, filed on August 3, 2016, the entire contents of which are incorporated herein by reference.

[0446] Industrial availability

[0447] In mobile communication systems, this can increase the likelihood of a successful handover.

Claims

1. A method for a terminal device configured to communicate with a first base station, the method comprising: The signal transmitted by the second base station using at least one beam is measured; The first information indicating the result of the measurement is sent to the first base station; An RRC message is received from the first base station. The RRC message includes second information related to the beam, including that the RRC message in the acknowledgment message was sent from the second base station to the first base station in response to a request message, and that the request message including the first information was sent from the first base station to the second base station. as well as Based on the second information, a random access preamble signal is sent to the second base station. The second information is dedicated random access channel resource information, i.e., dedicated RACH resource information.

2. The method according to claim 1, in, The confirmation message includes a container to be sent to the terminal device to initiate a handover from the first base station to the second base station.

3. The method according to claim 1 or 2, in, The request message is a switch request message, and The confirmation message is a switch request confirmation message.

4. The method according to claim 1 or 2, in, The measurement results include preferred beamforming weights corresponding to the beam.

5. The method according to claim 1 or 2, in, The second information includes information related to the resources used by the beam.

6. The method according to claim 1 or 2, in, The second information includes information related to the retransmission period of the beam.

7. A terminal device configured to communicate with a first base station, the terminal device comprising: A processor for measuring signals transmitted by a second base station using at least one beam; A transmitter is used to send first information indicating the result of the measurement to the first base station; as well as A receiver is configured to receive an RRC message from the first base station, the RRC message including second information related to the beam. The RRC message included in the confirmation message is sent from the second base station to the first base station in response to the request message. The request message, which includes the first information, is sent from the first base station to the second base station. The transmitter sends a random access preamble signal to the second base station based on the second information. The second information is dedicated random access channel resource information, i.e., dedicated RACH resource information.

8. A method for using a second base station, the second base station being configured to communicate with a first base station and a terminal device, the method comprising: In response to the request message, an acknowledgment message including an RRC message is sent to the first base station, wherein the RRC message includes second information related to the beam; and The terminal device receives a request message from the first base station, including first information indicating the measurement result, and receives a random access preamble signal based on the second information. The second information is dedicated random access channel resource information, i.e., dedicated RACH resource information.

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