FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the Invention:
“COMMUNICATION SYSTEM”
2. APPLICANT (S) –
(a) Name : MITSUBISHI ELECTRIC CORPORATION
(b) Nationality : Japanese
(c) Address : 7-3, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008310, Japan
The following specification particularly describes the invention and the manner
in which it is to be performed.
2
Field
[0001] The present disclosure relates to wireless communication technology.
Background
5 [0002] In the 3rd Generation Partnership Project (3GPP), which is an association for
standardizing mobile communication systems, fifth-generation (hereinafter may be
referred to as “5G”) wireless access systems have been developed as a successor to Long
Term Evolution (LTE) and Long Term Evolution Advanced (LTE-A) (see Non Patent
Literature 1), which is one of fourth-generation wireless access systems (for example,
10 Non Patent Literature 2). Technology for 5G wireless sections is referred to as “New
Radio Access Technology” (“New Radio” is abbreviated as “NR”). NR systems have
been developed based on the LTE systems and the LTE-A systems.
[0003] For example, in Europe, requirements for 5G have been compiled by an
15 association called METIS (see Non Patent Literature 3). The requirements for 5G
wireless access systems include 1000 times larger system capacity, 100 times higher
data transmission rate, 1/5 lower data processing latency, and 100 times more
communication terminals simultaneously connected than LTE systems, so as to achieve
further reduction in power consumption and reduction in device cost (see Non Patent
20 Literature 3).
[0004] In order to satisfy these requirements, 3GPP has devised 5G standards (see Non
Patent Literatures 4 to 23).
25 [0005] As NR access schemes, Orthogonal Frequency Division Multiplexing (OFDM)
is used for downlink, and OFDM and Discrete Fourier Transform-spread-OFDM (DFTs-OFDM) is used for uplink. In addition, similarly to LTE and LTE-A, 5G systems do
not include circuit switching and include only a packet communication scheme.
30 [0006] NR allows for the use of higher frequencies than LTE to improve transmission
speed and reduce processing delay.
3
[0007] NR, in which higher frequencies than LTE may be used, ensures cell coverage
by forming a narrow beam-shaped transmission/reception range (beamforming) and
changing the beam direction (beamsweeping).
5 [0008] The 3GPP agreements regarding frame configurations for NR systems described
in Non Patent Literature 1 (Chapter 5) will be described with reference to FIG. 1. FIG.
1 is an explanatory diagram illustrating a configuration of a radio frame for use in an
NR-based communication system. In FIG. 1, one radio frame is 10 ms long. A radio
frame is divided into 10 equally sized subframes. In the frame configuration of NR, one
10 or more numerologies, that is, one or more subcarrier spacings (SCS), are supported.
Regardless of subcarrier spacing in NR, one subframe is 1 ms long, and one slot is
composed of 14 symbols. In addition, the number of slots included in one subframe is
one in a subcarrier spacing of 15 kHz, and the number of slots in another subcarrier
spacing increases in proportion to subcarrier spacing (see Non Patent Literature 11
15 (3GPP TS38.211)).
[0009] The 3GPP agreements regarding channel configurations for NR systems are
described in Non Patent Literature 2 (Chapter 5) and Non Patent Literature 11.
20 [0010] Physical Broadcast Channel (PBCH) is a channel for downlink transmission
from base station devices (hereinafter may be simply referred to as “base stations”) to
communication terminal devices (hereinafter may be simply referred to as
“communication terminals”) such as mobile terminal devices (hereinafter may be
referred to as “mobile terminals” or “terminals”). The PBCH is transmitted together
25 with a downlink synchronization signal.
[0011] The downlink synchronization signals in NR are classified as primary
synchronization signals (P-SS) and secondary synchronization signals (S-SS).
Synchronization signals are transmitted as a synchronization signal burst (hereinafter
30 may be referred to as an SS burst) from the base station at predetermined intervals for a
predetermined duration. The SS burst includes a synchronization signal block
(hereinafter may be referred to as an SS block) for each beam of the base station.
4
[0012] The base station transmits the SS block of each beam in different beams within
the duration of the SS burst. The SS block includes P-SS, S-SS, and PBCH.
5 [0013] Physical Downlink Control Channel (PDCCH) is a channel for downlink
transmission from base stations to communication terminals. The PDCCH carries
downlink control information (DCI). The DCI includes, for example, resource
allocation information of Downlink Shared Channel (DL-SCH), which is one of the
transport channels to be described later, resource allocation information of Paging
10 Channel (PCH), which is one of the transport channels to be described later, and hybrid
automatic repeat request (HARQ) information related to the DL-SCH. In addition, the
DCI may include an uplink scheduling grant. The DCI may include acknowledgement
(Ack)/negative acknowledgement (Nack) as a response signal to uplink transmission.
In addition, in order to flexibly switch between DL and UL in a slot, the DCI may
15 include a slot configuration indication (SFI). The PDCCH or DCI is also called a L1/L2
control signal.
[0014] In NR, a time and frequency domain that is a candidate including the PDCCH is
provided. This domain is referred to as a control resource set (CORESET). The
20 communications terminal monitors the CORESET, and acquires the PDCCH.
[0015] Physical Downlink Shared Channel (PDSCH) is a channel for downlink
transmission from base stations to communication terminals. Downlink shared channel
(DL-SCH) and PCH, which are transport channels, are mapped to the PDSCH.
25
[0016] Physical Uplink Control Channel (PUCCH) is a channel for uplink transmission
from communication terminals to base stations. The PUCCH carries uplink control
information (UCI). The UCI includes Ack/Nack which is a response signal to the
downlink transmission, channel state information (CSI), scheduling request (SR), and
30 the like. The CSI includes rank indicator (RI), precoding matrix indicator (PMI), and
channel quality indicator (CQI) report. The RI is rank information of a channel matrix
in multiple input multiple output (MIMO). The PMI is information of a precoding
5
weight matrix for use in MIMO. The CQI is quality information indicating the quality
of received data or channel quality. The UCI may be carried by the PUSCH described
below. The PUCCH or UCI is also called a L1/L2 control signal.
5 [0017] Physical Uplink Shared Channel (PUSCH) is a channel for uplink transmission
from communication terminals to base stations. To the PUSCH, Uplink Shared Channel
(UL-SCH) is mapped as one of the transport channels.
[0018] Physical Random Access Channel (PRACH) is a channel for uplink transmission
10 from communication terminals to base stations. The PRACH carries a random access
preamble.
[0019] Downlink reference signals (RS) are known as symbols for NR-based
communication systems. The following four types of downlink reference signals are
15 defined: Data demodulation reference signals (DM-RS) which are UE-specific reference
signals, phase tracking reference signals (PT-RS), positioning reference signals (PRS),
and channel state information reference signals (CSI-RS). The measurement of the
physical layer of the communication terminal includes reference signal received power
(RSRP) measurement and reference signal received quality (RSRQ) measurement.
20
[0020] Similarly, uplink reference signals are known as symbols for NR-based
communication systems. The following three types of uplink reference signals are
defined: Demodulation reference signals (DM-RS), phase tracking reference signals
(PT-RS), and sounding reference signals (SRS).
25
[0021] The transport channels described in Non Patent Literature 2 (Chapter 5) will be
described. Among the downlink transport channels, Broadcast Channel (BCH) is
broadcast to the entire coverage of the base station (cell). The BCH is mapped to
Physical Broadcast Channel (PBCH).
30
[0022] Retransmission control by HARQ is applied to Downlink Shared Channel (DLSCH). The DL-SCH can be broadcast to the entire coverage of the base station (cell).
6
The DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource
allocation is also called semi-persistent scheduling. The DL-SCH supports
discontinuous reception (DRX) at communication terminals in order to reduce the power
consumption of the communication terminals. The DL-SCH is mapped to the physical
5 downlink shared channel (PDSCH).
[0023] Paging Channel (PCH) supports DRX at communication terminals so that the
power consumption of the communication terminals can be reduced. The PCH is
required to be broadcast to the entire coverage of the base station (cell). The PCH is
10 mapped to physical resources such as the physical downlink shared channel (PDSCH)
dynamically available for traffic.
[0024] Retransmission control by HARQ is applied to Uplink Shared Channel (ULSCH) among the uplink transport channels. The UL-SCH supports dynamic or semi15 static resource allocation. Semi-static resource allocation is also called configured grant.
The UL-SCH is mapped to Physical Uplink Shared Channel (PUSCH).
[0025] Random Access Channel (RACH) is limited to control information. The RACH
has a risk of collision. The RACH is mapped to Physical Random Access Channel
20 (PRACH).
[0026] HARQ will be described. HARQ is a technology for improving the
communication quality of transmission paths by combining automatic repeat request
(ARQ) and forward error correction. HARQ is advantageous for transmission paths
25 with changing communication quality because error correction effectively functions
through retransmission. In particular, further improvement in quality can be obtained
through retransmission by combining the reception result of the first transmission and
the reception result of the retransmission.
30 [0027] An example of a retransmission method will be described. If the reception side
cannot correctly decode the received data, in other words, if a cyclic redundancy check
(CRC) error occurs (CRC=NG), then “Nack” is transmitted from the reception side to
7
the transmission side. Upon receiving “Nack”, the transmission side retransmits the
data. If the reception side can correctly decode the received data, in other words, if no
CRC error occurs (CRC=OK), then “Ack” is transmitted from the reception side to the
transmission side. Upon receiving “Ack”, the transmission side transmits the next data.
5
[0028] Another example of a retransmission method will be described. In a case where
a CRC error occurs on the reception side, a retransmission request is made from the
reception side to the transmission side. The retransmission request is made by toggling
of a new data indicator (NDI). Upon receiving the retransmission request, the
10 transmission side retransmits the data. In a case where a CRC error does not occur on
the reception side, the retransmission request is not made. In a case where the
transmission side does not receive the retransmission request for a predetermined period
of time, it is considered that a CRC error has not occurred on the reception side.
15 [0029] The logical channels described in Non Patent Literature 1 (Chapter 6) will be
described. Broadcast Control Channel (BCCH) is a downlink channel for broadcasting
system control information. The BCCH, which is a logical channel, is mapped to a
transport channel: broadcast channel (BCH) or downlink shared channel (DL-SCH).
20 [0030] Paging Control Channel (PCCH) is a downlink channel for transmitting a change
in paging information and system information. The PCCH, which is a logical channel,
is mapped to Paging Channel (PCH), which is a transport channel.
[0031] Common Control Channel (CCCH) is a channel for transmitting control
25 information between communication terminals and base stations. The CCCH is used
when a communication terminal does not have an RRC connection with the network.
In downlink, the CCCH is mapped to the downlink shared channel (DL-SCH), which is
a transport channel. In the uplink direction, the CCCH is mapped to the uplink shared
channel (UL-SCH), which is a transport channel.
30
[0032] Dedicated Control Channel (DCCH) is a channel for transmitting dedicated
control information between communication terminals and the network on a one-to-one
8
basis. The DCCH is used when a communication terminal has an RRC connection with
the network. The DCCH is mapped to the uplink shared channel (UL-SCH) in uplink,
and is mapped to the downlink shared channel (DL-SCH) in downlink.
5 [0033] Dedicated Traffic Channel (DTCH) is a channel for one-to-one communication
with communication terminals for transmitting user information. The DTCH exists in
both uplink and downlink. The DTCH is mapped to the uplink shared channel (ULSCH) in uplink, and is mapped to the downlink shared channel (DL-SCH) in downlink.
10 [0034] The position tracking of a communication terminal is performed in units of
segments each consisting of one or more cells. The position tracking is performed to
track the position of the communication terminal even in the idle state and call the
communication terminal, in other words, enable the communication terminal to receive
a call. Segments for the position tracking of the communication terminal are referred to
15 as tracking areas.
[0035] NR supports calling of a communication terminal in a range the unit of which is
an area smaller than the tracking area. This range is referred to as a RAN notification
area (RNA). Paging of the communication terminal in the RRC_INACTIVE state,
20 which will be described later, is performed in this range.
[0036] NR employs Carrier Aggregation (CA), in which two or more Component
Carriers (CCs) are aggregated in order to support wider transmission bandwidths up to
100 MHz. CA is described in Non Patent Literature 1.
25
[0037] When CA is configured, a communication terminal, or a UE, has only one RRC
connection with a network (NW). In the RRC connection, one serving cell provides
NAS mobility information and security input. This cell is referred to as a Primary Cell
(PCell). Depending on UE capabilities, a Secondary Cell (SCell) can be configured to
30 form a set of serving cells together with the PCell. A set of serving cells consisting of
one PCell and one or more SCells is configured for one UE.
9
[0038] 3GPP has Dual Connectivity (abbreviated as DC), in which a UE is connected
to and communicates with two base stations in order to further increase the
communication capacity. DC is described in Non Patent Literatures 1 and 22.
5 [0039] One of the base stations that perform dual connectivity (DC) may be referred to
as a “master base station (MN)”, and the other may be referred to as a “secondary base
station (SN)”. The serving cells configured by the master base station may be
collectively referred to as a master cell group (MCG), and the serving cells configured
by the secondary base station may be collectively referred to as a secondary cell group
10 (SCG). In the DC, a primary cell in the MCG or the SCG is referred to as a special cell
(SpCell or SPCell). A special cell in the MCG is referred to as a PCell, and a special
cell in the SCG is referred to as a primary SCG cell (PSCell).
[0040] In addition, NR reduces the power consumption of a UE by allowing a base
15 station to set a part of the carrier frequency band (hereinafter may be referred to as a
bandwidth part (BWP)) in advance for the UE so that the UE can perform transmission
and reception with the base station using the BWP.
[0041] In addition, 3GPP has developed a framework for supporting services (or
20 applications) using sidelink (SL) communication (also referred to as PC5
communication) in both the Evolved Packet System (EPS) to be described later and the
5G core system (see Non Patent Literatures 1, 2, and 26 to 28). In SL communication,
communication is performed between terminals. Examples of services using SL
communication include vehicle-to-everything (V2X) services and proximity-based
25 services. In SL communication, not only direct communication between terminals but
also communication between UE and NW via a relay has been proposed (See Non Patent
Literatures 26 and 28).
[0042] Physical channels for use in SL (see Non Patent Literatures 2 and 11) will be
30 described. Physical Sidelink Broadcast Channel (PSBCH) carries information related
to the system and synchronization and is transmitted from UE.
10
[0043] Physical Sidelink Control Channel (PSCCH) carries control information from
UE for sidelink communication and V2X sidelink communication.
[0044] Physical Sidelink Shared Channel (PSSCH) carries data from UE for sidelink
communication and V2X sidelink communication.
5
[0045] Physical Sidelink Feedback Channel (PSFCH) carries HARQ feedback on the
sidelink from the UE that has received the PSSCH transmission to the UE that has
transmitted the PSSCH.
10 [0046] Transport channels for use in SL (see Non Patent Literature 1) will be described.
Sidelink Broadcast Channel (SL-BCH) has a predetermined transport format and is
mapped to the physical channel PSBCH.
[0047] Sidelink Shared Channel (SL-SCH) supports broadcast transmission. The SL15 SCH supports both UE autonomous resource selection and resource allocation
scheduled by the base station. There is a collision risk in the UE autonomous resource
selection, and there is no collision when the UE is allocated individual resources by the
base station. The SL-SCH also supports dynamic link adaptation by changing
transmission power, modulation, and coding. The SL-SCH is mapped to the physical
20 channel PSSCH.
[0048] Logical channels for use in SL (see Non Patent Literature 2) will be described.
Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for broadcasting
sidelink system information from one UE to other UEs. The SBCCH is mapped to the
25 transport channel SL-BCH.
[0049] Sidelink Traffic Channel (STCH) is a one-to-many sidelink traffic channel for
transmitting user information from one UE to other UEs. The STCH is used only by
UEs having sidelink communication capability and UEs having V2X sidelink
30 communication capability. One-to-one communication between two UEs having
sidelink communication capability is also implemented by the STCH. The STCH is
mapped to the transport channel SL-SCH.
11
[0050] Sidelink Control Channel (SCCH) is a control channel for sidelink for
transmitting control information from one UE to other UEs. The SCCH is mapped to
the transport channel SL-SCH.
5
[0051] In LTE, SL communication is applied only to broadcast. In NR, SL
communication is designed to support unicast and groupcast in addition to broadcast
(see Non Patent Literature 27 (3GPP TS23.287)).
10 [0052] Unicast communication and groupcast communication in SL support HARQ
feedback (Ack/Nack), CSI reporting, and the like.
[0053] In addition, 3GPP has developed Integrated Access and Backhaul (IAB), in
which both an access link that is a link between UE and a base station and a backhaul
15 link that is a link between base stations are wirelessly performed (see Non Patent
Literatures 2, 20, and 29).
[0054] 3GPP has also developed several new technologies. For example, application
of positioning technology has been developed, among which low-power-consumption
20 and high-accuracy positioning has been developed (see Non Patent Literature 37).
Citation List
Non Patent Literature
[0055] Non Patent Literature 1: 3GPP TS36.300 V16.7.0
25 Non Patent Literature 2: 3GPP TS38.300 V16.8.0
Non Patent Literature 3: “Scenarios, requirements and KPIs for 5G
mobile and wireless system”, ICT-317669-METIS/D1.1
Non Patent Literature 4: 3GPP TR23.799 V14.0.0
Non Patent Literature 5: 3GPP TR38.801 V14.0.0
30 Non Patent Literature 6: 3GPP TR38.802 V14.2.0
Non Patent Literature 7: 3GPP TR38.804 V14.0.0
Non Patent Literature 8: 3GPP TR38.912 V16.0.0
12
Non Patent Literature 9: 3GPP RP-172115
Non Patent Literature 10: 3GPP TS23.501 V17.3.0
Non Patent Literature 11: 3GPP TS38.211 V17.0.0
Non Patent Literature 12: 3GPP TS38.212 V17.0.0
5 Non Patent Literature 13: 3GPP TS38.213 V17.0.0
Non Patent Literature 14: 3GPP TS38.214 V17.0.0
Non Patent Literature 15: 3GPP TS38.321 V16.7.0
Non Patent Literature 16: 3GPP TS38.322 V16.2.0
Non Patent Literature 17: 3GPP TS38.323 V16.6.0
10 Non Patent Literature 18: 3GPP TS37.324 V16.3.0
Non Patent Literature 19: 3GPP TS38.331 V16.7.0
Non Patent Literature 20: 3GPP TS38.401 V16.8.0
Non Patent Literature 21: 3GPP TS38.413 V16.8.0
Non Patent Literature 22: 3GPP TS37.340 V16.8.0
15 Non Patent Literature 23: 3GPP TS38.423 V16.8.0
Non Patent Literature 24: 3GPP TS38.305 V16.7.0
Non Patent Literature 25: 3GPP TS23.273 V17.3.0
Non Patent Literature 26: 3GPP TR23.703 V12.0.0
Non Patent Literature 27: 3GPP TS23.287 V17.2.0
20 Non Patent Literature 28: 3GPP TS23.303 V17.0.0
Non Patent Literature 29: 3GPP TS38.340 V16.5.0
Non Patent Literature 30: 3GPP TS38.455 V16.6.0
Non Patent Literature 31: 3GPP TS37.355 V16.7.0
Non Patent Literature 32: 3GPP TR38.875 V17.0.0
25 Non Patent Literature 33: 3GPP RP-210655
Non Patent Literature 34: 3GPP RP-210982
Non Patent Literature 35: 3GPP RP-211742
Non Patent Literature 36: 3GPP RP-212802
Non Patent Literature 37: 3GPP RP-213588
30 Non Patent Literature 38: 3GPP TS38.304 V16.7.0
Non Patent Literature 39: 3GPP TS24.501 V17.5.0
Non Patent Literature 40: 3GPP TR38.857 V17.0.0
13
Non Patent Literature 41: 3GPP R2-2111374
Non Patent Literature 42: 3GPP TS37.320 V16.7.0
Summary of Invention
5 Problem to be solved by the Invention
[0056] In 5G-based UE positioning, the UE to be subjected to positioning may be in the
RRC_INACTIVE state. Location management function (LMF) (see Non Patent
Literature 24 (3GPP TS 38.305)) constituting the 5G-based communication system may
10 configure the positioning signal setting so as to transmit the positioning signal at the
paging timing of the UE. However, the paging timing is determined by using the
identifier of the UE and the parameter that is broadcast as system information.
Therefore, a change in the paging timing affects the paging timing of other UEs, leading
to a problem that the communication system is complicated.
15
[0057] In view of the above problems, an object of the present disclosure is to realize
avoidance of complexity in the positioning of a communication terminal in a
communication system.
20 Means to Solve the Problem
[0058] A communication system according to the present disclosure is a communication
system to which a fifth-generation wireless access system is applied, the communication
system comprising: a network-side device equipped with a location management
function of the fifth-generation wireless access system; and a base station, wherein in a
25 case where a positioning request for a communication terminal connected to the base
station occurs, the base station to which a positioning target terminal that is a
communication terminal to be subjected to positioning is connected notifies the
network-side device of information related to a timing at which the positioning target
terminal is able to receive a positioning signal, and the network-side device determines
30 setting contents related to a transmission/reception timing of a positioning signal based
on the information provided from the base station, and notifies the base station that
transmits the positioning signal and the positioning target terminal of the setting
14
contents determined.
Effects of the Invention
[0059] A communication system according to the present disclosure can achieve the
5 effect of realizing avoidance of complexity in the positioning of a communication
terminal.
[0060] Objects, features, aspects, and advantages of the present disclosure will become
more apparent from the following detailed description and the accompanying drawings.
10 Brief Description of Drawings
[0061] FIG. 1 is an explanatory diagram illustrating a configuration of a radio frame for
use in an NR-based communication system.
FIG. 2 is a block diagram illustrating an overall configuration of an NR-based
communication system 210 discussed in 3GPP.
15 FIG. 3 is a diagram illustrating a DC configuration with a base station connected
to an NG core.
FIG. 4 is a block diagram illustrating a configuration of the mobile terminal 202
illustrated in FIG. 2.
FIG. 5 is a block diagram illustrating a configuration of the base station 213
20 illustrated in FIG. 2.
FIG. 6 is a block diagram illustrating a configuration of a 5GC unit.
FIG. 7 is a flowchart schematically illustrating the procedure from a cell search
to an idle operation performed by a communication terminal (UE) in an NR-based
communication system.
25 FIG. 8 is a diagram illustrating an exemplary configuration of a cell in the NR
system.
FIG. 9 is a connection configuration diagram illustrating an exemplary
connection configuration of terminals in the SL communication.
FIG. 10 is a connection configuration diagram illustrating an exemplary
30 connection configuration of a base station supporting Integrated Access and Backhaul.
FIG. 11 is a sequence diagram illustrating an example of a first half of a
positioning sequence related to the UE in RRC_INACTIVE according to the first
15
embodiment.
FIG. 12 is a sequence diagram illustrating an example of a second half of a
positioning sequence related to the UE in RRC_INACTIVE according to the first
embodiment.
5 FIG. 13 is a sequence diagram illustrating a first other example of a positioning
sequence related to the UE in RRC_INACTIVE according to the first embodiment.
FIG. 14 is a sequence diagram illustrating a second other example of a
positioning sequence related to the UE in RRC_INACTIVE according to the first
embodiment.
10 FIG. 15 is a sequence diagram illustrating an example of a positioning sequence
in which the UE notifies the AMF of the positioning capability of the UE in advance
according to the first modification of the first embodiment.
FIG. 16 is a sequence diagram illustrating an example of a positioning sequence
in which the AMF notifies the LMF of information related to the base station that covers
15 the UE according to the second embodiment.
FIG. 17 is a sequence diagram illustrating an example of a positioning procedure
involving the cell reselection of the UE according to the second embodiment.
FIG. 18 is a sequence diagram illustrating an example of a positioning procedure
in the reduced capability UE according to the third embodiment.
20 FIG. 19 is a sequence diagram illustrating another example of a positioning
procedure in the reduced capability UE according to the third embodiment.
FIG. 20 is a diagram illustrating an example in which the code sequence of the
positioning signal is reallocated within a band in which the reduced capability UE can
perform transmission and reception according to the third embodiment.
25 FIG. 21 is a diagram illustrating an example in which the code sequence of the
positioning signal is not reallocated within a band in which the reduced capability UE
can perform transmission and reception according to the third embodiment.
Description of Embodiments
30 [0062] First Embodiment.
FIG. 2 is a block diagram illustrating an overall configuration of an NR-based
communication system 210 discussed in 3GPP. Below is a description of FIG. 2. The
16
wireless access network is referred to as a Next Generation Radio Access Network (NGRAN) 211. A mobile terminal device (hereinafter referred to as a “mobile terminal or
user equipment (UE)”) 202 which is a communication terminal device can wirelessly
communicate with a base station device (hereinafter referred to as an “NR base station
5 (NG-RAN NodeB (gNB)”) 213, and transmits and receives signals by wireless
communication. The NG-RAN 211 includes one or more NR base stations 213.
[0063] Here, “communication terminal devices” include not only mobile terminal
devices such as mobile phone terminal devices that can move but also non-moving
10 devices such as sensors. In the following description, a “communication terminal device”
may be simply referred to as a “communication terminal”.
[0064] Access Stratum (AS) protocol is terminated between the UE 202 and the NGRAN 211. As the AS control protocol, for example, Radio Resource Control (RRC),
15 Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP),
Radio Link Control (RLC), Medium Access Control (MAC), or Physical layer (PHY)
is used. RRC is used in control plane (hereinafter may be referred to as C-plane), SDAP
is used in user plane (hereinafter may be referred to as U-plane) and PDCP, MAC, RLC,
and PHY are used in both C-plane and U-plane.
20
[0065] The control protocol “Radio Resource Control (RRC)” between the UE 202 and
the NR base station 213 performs broadcast, paging, RRC connection management, and
the like. The states of the NR base station 213 and the UE 202 in RRC are classified as
RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.
25
[0066] In RRC_IDLE, public land mobile network (PLMN) selection, system
information (SI) broadcast, paging, cell re-selection, mobility, and the like are
performed. In RRC_CONNECTED, the mobile terminal has an RRC connection and
can transmit and receive data to and from the network. In RRC_CONNECTED,
30 handover (HO), measurement of a neighbor cell, and the like are performed. In
RRC_INACTIVE, the connection between a 5G core unit 214 and the NR base station
213 is maintained, and meanwhile system information (SI) broadcast, paging, cell re-
17
selection, mobility, and the like are performed.
[0067] The gNB 213 is connected via an NG interface to the 5G core unit (hereinafter
may be referred to as the “5GC unit”) 214 including an Access and Mobility
5 Management Function (AMF), a Session Management Function (SMF), a User Plane
Function (UPF), or the like. Control information and/or user data is communicated
between the gNB 213 and the 5GC unit 214. The NG interface is a generic term for the
N2 interface between the gNB 213 and the AMF 220, the N3 interface between the gNB
213 and the UPF 221, the N11 interface between the AMF 220 and the SMF 222, and
10 the N4 interface between the UPF 221 and the SMF 222. A plurality of 5GC units 214
may be connected to one gNB 213. Different gNBs 213 are connected by an Xn
interface, and control information and/or user data is communicated between the gNBs
213.
15 [0068] The 5GC unit 214 is a higher-level device, specifically, a higher-level node, and
performs control of connection between the NR base station 213 and the mobile terminal
(UE) 202, distribution of a paging signal to one or more NR base stations (gNBs) 213
and/or LTE base stations (E-UTRAN NodeB: eNB), and the like. The 5GC unit 214
also performs mobility control in the idle state. The 5GC unit 214 manages a tracking
20 area list when the mobile terminal 202 is in the idle state, inactive state, and active state.
The 5GC unit 214 starts the paging protocol by transmitting a paging message to a cell
belonging to a tracking area in which the mobile terminal 202 is registered.
[0069] The gNB 213 may configure one or more cells. In a case where one gNB 213
25 configures a plurality of cells, every single cell is configured to be able to communicate
with the UE 202.
[0070] The gNB 213 may be divided into a central unit (hereinafter may be referred to
as CU) 215 and a distributed unit (hereinafter may be referred to as DU) 216. One CU
30 215 is configured in the gNB 213. One or more DUs 216 are configured in the gNB
213. One DU 216 constitutes one or more cells. The CU 215 is connected to the DU
216 by an F1 interface, and control information and/or user data is communicated
18
between the CU 215 and the DU 216. The F1 interface includes an F1-C interface and
an F1-U interface. The CU 215 is responsible for the functions of the RRC, SDAP, and
PDCP protocols, and the DU 216 is responsible for the functions of the RLC, MAC, and
PHY protocols. One or more transmission reception points (TRPs) 219 may be
5 connected to the DU 216. The TRP 219 transmits and receives wireless signals to and
from the UE.
[0071] The CU 215 may be divided into a CU for C-plane (CU-C) 217 and a CU for Uplane (CU-U) 218. One CU-C 217 is configured in the CU 215. One or more CU-Us
10 218 are configured in the CU 215. The CU-C 217 is connected to the CU-U 218 by an
E1 interface, and control information is communicated between the CU-C 217 and the
CU-U 218. The CU-C 217 is connected to the DU 216 via the F1-C interface, and
control information is communicated between the CU-C 217 and the DU 216. The CUU 218 is connected to the DU 216 by the F1-U interface, and user data is communicated
15 between the CU-U 218 and the DU 216.
[0072] In the 5G-based communication system, the Unified Data Management (UDM)
function and the Policy Control Function (PCF) described in Non Patent Literature 10
(3GPP TS23.501) may be included. The UDM and/or the PCF may be included in the
20 5GC unit 214 in FIG. 214.
[0073] In the 5G-based communication system, the Location Management Function
(LMF) described in Non Patent Literature 24 (3GPP TS38.305) may be provided. The
LMF may be connected to the base station via the AMF as disclosed in Non Patent
25 Literature 25 (3GPP TS23.273).
[0074] In the 5G-based communication system, the Non-3GPP Interworking Function
(N3IWF) described in Non Patent Literature 10 (3GPP TS23.501) may be included. The
N3IWF may terminate the Access Network (AN) with the UE in non-3GPP access with
30 the UE.
[0075] FIG. 3 is a diagram illustrating a dual connectivity (DC) configuration for
19
connection to an NG core. In FIG. 3, a solid line indicates a U-Plane connection, and a
broken line indicates a C-Plane connection. In FIG. 3, a master base station 240-1 may
be a gNB or an eNB. In addition, a secondary base station 240-2 may be a gNB or an
eNB. For example, in FIG. 3, a DC configuration in which the master base station 240-
5 1 is a gNB and the secondary base station 240-2 is an eNB may be referred to as NGEN-DC. Although FIG. 3 illustrates an example in which the U-Plane connection
between the 5GC unit 214 and the secondary base station 240-2 is established via the
master base station 240-1, the U-Plane connection may be directly established between
the 5GC unit 214 and the secondary base station 240-2. Further, in FIG. 3, instead of
10 the 5GC unit 214, an evolved packet core (EPC) which is a core network connected to
the LTE system or the LTE-A system may be connected to the master base station 240-
1. The U-Plane connection between the EPC and the secondary base station 240-2 may
be directly established.
15 [0076] FIG. 4 is a block diagram illustrating a configuration of the mobile terminal 202
illustrated in FIG. 2. A transmission process in the mobile terminal 202 illustrated in
FIG. 4 will be described. First, control data from a control unit 310 and user data from
an application unit 302 are sent to a protocol processing unit 301. Control data and user
data may be buffered. A buffer for control data and user data may be provided in the
20 control unit 310, in the application unit 302, or in the protocol processing unit 301. The
protocol processing unit 301 performs protocol processing such as SDAP, PDCP, RLC,
and MAC, for example, determining a transmission destination base station in DC or
the like, adding a header in each protocol, and the like. The data that has undergone the
protocol processing is passed to an encoder unit 304 and subjected to encoding such as
25 error correction. Some data may be directly output from the protocol processing unit
301 to a modulation unit 305 without being subjected to encoding. The data encoded
by the encoder unit 304 is subjected to modulation in the modulation unit 305. The
modulation unit 305 may perform precoding for MIMO. The modulated data is
converted into a baseband signal and then output to a frequency conversion unit 306 to
30 be converted into a wireless transmission frequency. Thereafter, the transmission
signals are transmitted from antennas 307-1 to 307-4 to the base station 213. FIG. 4
illustrates the case where the number of antennas is four, but the number of antennas is
20
not limited to four.
[0077] A reception process in the mobile terminal 202 is executed as follows. Wireless
signals from the base station 213 are received by the antennas 307-1 to 307-4. The
5 reception signal is converted from the wireless reception frequency into a baseband
signal in the frequency conversion unit 306, and demodulation is performed in a
demodulation unit 308. The demodulation unit 308 may perform weight calculation and
multiplication. The demodulated data is passed to a decoder unit 309, and decoding
such as error correction is performed. The decoded data is passed to the protocol
10 processing unit 301, and protocol processing such as MAC, RLC, PDCP, and SDAP,
for example, an operation such as removal of a header in each protocol, is performed.
Among the data that has undergone the protocol processing, the control data is passed
to the control unit 310, and the user data is passed to the application unit 302.
15 [0078] A series of processes of the mobile terminal 202 is controlled by the control unit
310. Therefore, the control unit 310 is also connected to the respective units 302 and
304 to 309, which is not illustrated in FIG. 4.
[0079] Each unit of the mobile terminal 202, for example, the control unit 310, the
20 protocol processing unit 301, the encoder unit 304, and the decoder unit 309, is
implemented by, for example, processing circuitry including a processor and a memory.
For example, the control unit 310 is implemented by the processor executing a program
in which a series of processes of the mobile terminal 202 is described. The program in
which a series of processes of the mobile terminal 202 is described is stored in the
25 memory. The memory is exemplified by a nonvolatile or volatile semiconductor
memory such as a random access memory (RAM), a read only memory (ROM), or a
flash memory. Each unit of the mobile terminal 202, for example, the control unit 310,
the protocol processing unit 301, the encoder unit 304, and the decoder unit 309, may
be implemented by dedicated processing circuitry such as a field programmable gate
30 array (FPGA), an application specific integrated circuit (ASIC), or a digital signal
processor (DSP). In FIG. 4, the number of antennas used for transmission and the
number of antennas used for reception by the mobile terminal 202 may be the same or
21
different.
[0080] FIG. 5 is a block diagram illustrating a configuration of the base station 213
illustrated in FIG. 2. A transmission process in the base station 213 illustrated in FIG.
5 5 will be described. An EPC communication unit 401 transmits and receives data
between the base station 213 and the EPC. A 5GC communication unit 412 transmits
and receives data between the base station 213 and the 5GC (such as the 5GC unit 214).
An other base station communication unit 402 transmits and receives data to and from
other base stations. The EPC communication unit 401, the 5GC communication unit
10 412, and the other base station communication unit 402 each exchange information with
a protocol processing unit 403. Control data from a control unit 411 and user data and
control data from the EPC communication unit 401, the 5GC communication unit 412,
and the other base station communication unit 402 are sent to the protocol processing
unit 403. Control data and user data may be buffered. A buffer for control data and
15 user data may be provided in the control unit 411, in the EPC communication unit 401,
in the 5GC communication unit 412, or in the other base station communication unit
402.
[0081] The protocol processing unit 403 performs protocol processing such as SDAP,
20 PDCP, RLC, and MAC, for example, routing transmission data in DC or the like, adding
a header in each protocol, and the like. The data that has undergone the protocol
processing is passed to an encoder unit 405 and subjected to encoding such as error
correction. Some data may be directly output from the protocol processing unit 403 to
a modulation unit 406 without being subjected to encoding. In addition, data may be
25 sent from the protocol processing unit 403 to the other base station communication unit
402. For example, in the DC, data sent from the 5GC communication unit 412 or the
EPC communication unit 401 may be sent to another base station, for example, a
secondary base station, via the other base station communication unit 402. The encoded
data is subjected to modulation in the modulation unit 406. The modulation unit 406
30 may perform precoding for MIMO. The modulated data is converted into a baseband
signal and then output to a frequency conversion unit 407 to be converted into a wireless
transmission frequency. Thereafter, the transmission signals are transmitted from
22
antennas 408-1 to 408-4 to one or more mobile terminals 202. FIG. 5 illustrates the case
where the number of antennas is four, but the number of antennas is not limited to four.
[0082] A reception process in the base station 213 is executed as follows. Wireless
5 signals from one or more mobile terminals 202 are received by the antennas 408-1 to
408-4. The reception signal is converted from the wireless reception frequency into a
baseband signal in the frequency conversion unit 407, and demodulation is performed
in a demodulation unit 409. The demodulated data is passed to a decoder unit 410, and
decoding such as error correction is performed. The decoded data is passed to the
10 protocol processing unit 403, and protocol processing such as MAC, RLC, PDCP, and
SDAP, for example, an operation such as removal of a header in each protocol, is
performed. Among the data that has undergone the protocol processing, the control data
is passed to the control unit 411, the 5GC communication unit 412, the EPC
communication unit 401, or the other base station communication unit 402, and the user
15 data is passed to the 5GC communication unit 412, the EPC communication unit 401,
or the other base station communication unit 402. Data sent from the other base station
communication unit 402 may be sent to the 5GC communication unit 412 or the EPC
communication unit 401. The data may be, for example, uplink data that is sent to the
5GC communication unit 412 or the EPC communication unit 401 via another base
20 station in the DC.
[0083] A series of processes of the base station 213 is controlled by the control unit 411.
Therefore, the control unit 411 is also connected to the respective units 401, 402, 405 to
410, and 412, which is not illustrated in FIG. 5.
25
[0084] Each unit of the base station 213, for example, the control unit 411, the protocol
processing unit 403, the 5GC communication unit 412, the EPC communication unit
401, the other base station communication unit 402, the encoder unit 405, and the
decoder unit 410, is implemented by processing circuitry including a processor and a
30 memory, or dedicated processing circuitry such as FPGA, ASIC, or DSP, similarly to
the mobile terminal 202 described above. In FIG. 5, the number of antennas used for
transmission and the number of antennas used for reception by the base station 213 may
23
be the same or different.
[0085] As an example of the configuration of the CU 215 illustrated in FIG. 2, one
including a DU communication unit may be used except for the encoder unit 405, the
5 modulation unit 406, the frequency conversion unit 407, the antennas 408-1 to 408-4,
the demodulation unit 409, and the decoder unit 410 illustrated in FIG. 5. The DU
communication unit is connected to the protocol processing unit 403. The protocol
processing unit 403 in the CU 215 performs protocol processing such as PDCP and
SDAP.
10
[0086] As an example of the configuration of the DU 216 illustrated in FIG. 2, a
configuration in which a CU communication unit is provided may be used except for
the EPC communication unit 401, the other base station communication unit 402, and
the 5GC communication unit 412 illustrated in FIG. 5. The CU communication unit is
15 connected to the protocol processing unit 403. The protocol processing unit 403 in the
DU 216 performs protocol processing such as PHY, MAC, and RLC.
[0087] FIG. 6 is a block diagram illustrating a configuration of a 5GC unit. FIG. 6
depicts the configuration of the 5GC unit 214 illustrated in FIG. 2 described above. FIG.
20 6 depicts a case where an AMF configuration, an SMF configuration, and a UPF
configuration are included in the 5GC unit 214 illustrated in FIG. 2. In the example
illustrated in FIG. 6, the AMF may have the function of a control plane control unit 525,
the SMF may have the function of a session management unit 527, and the UPF may
have the functions of a user plane communication unit 523 and a Data Network
25 communication unit 521. The Data Network communication unit 521 transmits and
receives data between the 5GC unit 214 and the Data Network. A base station
communication unit 522 transmits and receives data by means of the NG interface
between the 5GC unit 214 and the base station 213. The user data sent from the Data
Network is passed from the Data Network communication unit 521 to the base station
30 communication unit 522 via the user plane communication unit 523, and transmitted to
one or more base stations 213. The user data sent from the base station 213 is passed
from the base station communication unit 522 to the Data Network communication unit
24
521 via the user plane communication unit 523, and transmitted to the Data Network.
[0088] The control data sent from the base station 213 is passed from the base station
communication unit 522 to the control plane control unit 525. The control plane control
5 unit 525 may pass the control data to the session management unit 527. Control data
may be sent from the Data Network. The control data sent from the Data Network may
be sent from the Data Network communication unit 521 to the session management unit
527 via the user plane communication unit 523. The session management unit 527 may
send the control data to the control plane control unit 525.
10
[0089] The user plane control unit 523 includes a PDU processing unit 523-1, a mobility
anchoring unit 523-2, and the like, and performs general processing on the user plane
(hereinafter may be referred to as U-Plane.). The PDU processing unit 523-1 processes
data packets, for example, transmits and receives packets to and from the Data Network
15 communication unit 521 and transmits and receives packets to and from the base station
communication unit 522. The mobility anchoring unit 523-2 is responsible for
anchoring a data path at the time of mobility of the UE.
[0090] The session management unit 527 manages a PDU session provided between the
20 UE and the UPF. The session management unit 527 includes a PDU session controller
527-1, a UE IP address allocator 527-2, and the like. The PDU session controller 527-
1 manages a PDU session between the mobile terminal 202 and the 5GC unit 214. The
UE IP address allocator 527-2 performs, for example, allocation of an IP address to the
mobile terminal 202.
25
[0091] The control plane control unit 525 includes a NAS security unit 525-1, an Idle
State mobility management unit 525-2, and the like, and performs general processing
on the control plane (hereinafter may be referred to as C-Plane). The NAS security unit
525-1 ensures security of Non-Access Stratum (NAS) messages and the like. The Idle
30 State mobility management unit 525-2 performs, for example: mobility management in
the idle state (also referred to as RRC_IDLE state or simply as idle); generation and
control of paging signals in the idle state; and addition, deletion, update, and search of
25
tracking areas and management of tracking area lists for one or more mobile terminals
202 under control.
[0092] A series of processes of the 5GC unit 214 is controlled by a control unit 526.
5 Therefore, the control unit 526 is connected to the respective units 521 to 523, 525, and
527, which is not illustrated in FIG. 6. Similarly to the control unit 310 of the mobile
terminal 202 described above, each unit of the 5GC unit 214 is implemented by, for
example, processing circuitry including a processor and a memory, or by dedicated
processing circuitry such as FPGA, ASIC, or DSP.
10
[0093] Next, an example of a cell search method in a communication system will be
described. FIG. 7 is a flowchart schematically illustrating the procedure from a cell
search to an idle operation performed by a communication terminal (UE) in an NRbased communication system. Starting the cell search, the communication terminal
15 synchronizes the slot timing and the frame timing using the primary synchronization
signal (P-SS) and the secondary synchronization signal (S-SS) transmitted from a
nearby base station in step ST601.
[0094] The P-SS and the S-SS are collectively referred to as synchronization signals
20 (SS). The synchronization signals (SS) are allocated synchronization codes
corresponding one-to-one to physical cell identifiers (PCIs) allocated to cells. The
number of PCIs available is 1008. The communication terminal performs
synchronization using the 1008 PCIs and detects (identifies) the PCI of a synchronized
cell.
25
[0095] The communication terminal receives the PBCH in step ST602 for the next
synchronized cell. A Master Information Block (MIB) including cell configuration
information is mapped to the BCCH on the PBCH. Therefore, the MIB is obtained by
receiving the PBCH and obtaining the BCCH. Examples of the information of the MIB
30 include system frame number (SFN), scheduling information of system information
block (SIB) 1, subcarrier spacing of SIB 1 or the like, and information of DM-RS
position.
26
[0096] Further, the communication terminal acquires an SS block identifier from the
PBCH. A part of the bit string of the SS block identifier is included in the MIB. The
remaining part of the bit string is included in an identifier that is used for sequence
5 generation of the DM-RS accompanying the PBCH. The communication terminal
acquires the SS block identifier by using the MIB included in the PBCH and the DMRS sequence accompanying the PBCH.
[0097] Next, in step ST603, the communication terminal measures the received power
10 of the SS block.
[0098] Next, in step ST604, the communication terminal selects, from among the one
or more cells detected by step ST603, a cell having the best reception quality, e.g. a cell
having the highest received power, or the best cell. In addition, the communication
15 terminal selects a beam having the best reception quality, for example, a beam having
the highest received power of the SS block, that is, the best beam. For the selection of
the best beam, for example, the received power of the SS block for each SS block
identifier is used.
20 [0099] Next, in step ST605, the communication terminal receives the DL-SCH based
on the scheduling information of SIB1 included in the MIB, and obtains System
Information Block (SIB) 1 in the broadcast information BCCH. The SIB1 includes
information related to access to the cell, configuration information of the cell, and
scheduling information of other SIBs (SIBk; k is an integer of ≥2). The SIB1 also
25 includes a Tracking Area Code (TAC).
[0100] Next, in step ST606, the communication terminal compares the TAC of the SIB1
received in step ST605 with the TAC portion of the Tracking Area Identity (TAI) in the
tracking area list already held by the communication terminal. The tracking area list is
30 also referred to as the TAI list. The TAI is identification information for identifying the
tracking area, and includes a Mobile Country Code (MCC), a Mobile Network Code
(MNC), and a Tracking Area Code (TAC). The MCC is a country code. The MNC is
27
a network code. The TAC is the code number of the tracking area.
[0101] If the result of the comparison in step ST606 shows that the TAC received in
step ST605 is the same as the TAC included in the tracking area list, the communication
5 terminal starts the idle operation in the cell. If the comparison shows that the TAC
received in step ST605 is not included in the tracking area list, the communication
terminal requests, through the cell, the core network (EPC) including the MME and the
like to change the tracking area for performing Tracking Area Update (TAU).
10 [0102] A device constituting the core network (hereinafter may be referred to as a “corenetwork-side device”) updates the tracking area list based on the identification number
(such as UE-ID) of the communication terminal transmitted from the communication
terminal together with the TAU request signal. The core-network-side device transmits
the updated tracking area list to the communication terminal. The communication
15 terminal rewrites (updates) the TAC list held by the communication terminal based on
the received tracking area list. Thereafter, the communication terminal starts the idle
operation in the cell.
[0103] Next, an example of a random access method in a communication system will
20 be described. In the random access, four-step random access and two-step random
access are used. In addition, for each of the four-step random access and the two-step
random access, there are contention-based random access, that is, random access in
which timing collision with another mobile terminal may occur and contention-free
random access without collision.
25
[0104] An example of a contention-based four-step random access method will be
described. As a first step, the mobile terminal transmits a random access preamble to
the base station. The random access preamble may be selected by the mobile terminal
from a predetermined range, or may be individually assigned to mobile terminals and
30 provided as notification from the base station.
[0105] As a second step, the base station transmits a random access response to the
28
mobile terminal. The random access response includes the uplink scheduling
information that is used in a third step, the terminal identifier that is used in the uplink
transmission in the third step, and the like.
5 [0106] As the third step, the mobile terminal performs uplink transmission to the base
station. The mobile terminal uses the information acquired in the second step for uplink
transmission. As a fourth step, the base station notifies the mobile terminal of the
presence or absence of contention resolution. The mobile terminal that has been notified
that there is no contention ends the random access processing. The mobile terminal that
10 has been notified that there is a contention performs the processing again from the first
step.
[0107] The contention-free four-step random access method is different from the
contention-based four-step random access method in the following points. That is, prior
15 to the first step, the base station pre-allocates a random access preamble and uplink
scheduling to the mobile terminal. In addition, the notification of the presence or
absence of contention resolution in the fourth step is unnecessary.
[0108] An example of a contention-based two-step random access method will be
20 described. As a first step, the mobile terminal performs random access preamble
transmission and uplink transmission to the base station. As a second step, the base
station notifies the mobile terminal of the presence or absence of contention. The mobile
terminal that has been notified that there is no contention ends the random access
processing. The mobile terminal that has been notified that there is a contention
25 performs the processing again from the first step.
[0109] The collision-free two-step random access method is different from the
contention-based two-step random access method in the following points. That is, prior
to the first step, the base station pre-allocates a random access preamble and uplink
30 scheduling to the mobile terminal. In addition, in a second step, the base station
transmits a random access response to the mobile terminal.
29
[0110] FIG. 8 illustrates an exemplary configuration of a cell in NR. In the NR cell,
narrow beams are formed and transmitted in different directions. In the example
illustrated in FIG. 8, a base station 750 performs transmission and reception with mobile
terminals using a beam 751-1 in a certain time. In another time, the base station 750
5 performs transmission and reception with mobile terminals using a beam 751-2.
Similarly, the base station 750 performs transmission and reception with mobile
terminals using one or more of beams 751-3 to 751-8. In this way, the base station 750
configures a wide-range cell 752.
10 [0111] FIG. 8 illustrates an example in which the number of beams the base station 750
uses is eight, but the number of beams may be different from eight. In addition, the
number of beams the base station 750 simultaneously uses is one in the example
illustrated in FIG. 8, but may be two or more.
15 [0112] The concept of quasi-colocation (QCL) is used to identify the beam (see Non
Patent Literature 14 (3GPP TS 38.214)). That is, the beam is identified by information
indicating which reference signal (e.g. SS Block, CSI-RS) beam can be regarded as the
same as the beam. The information may include information related to the type of
information about a viewpoint from which beams can be regarded as the same, for
20 example, information related to Doppler shift, Doppler shift spread, average delay,
average delay spread, and spatial Rx parameters (see Non Patent Literature 14 (3GPP
TS 38.214)).
[0113] 3GPP supports sidelink (SL) for device-to-device (D2D) communication and
25 vehicle-to-vehicle (V2V) communication (see Non Patent Literature 1 and Non Patent
Literature 16). SL is defined by the PC5 interface.
[0114] SL communication is designed to support PC5-S signaling in order to support
unicast and groupcast in addition to broadcast (see Non Patent Literature 27 (3GPP
30 TS23.287)). For example, PC5-S signaling is performed to establish a link for
performing SL, i.e. PC5 communication. This link is implemented in the V2X layer and
is also referred to as the layer 2 link.
30
[0115] In addition, SL communication is designed to support RRC signaling (see Non
Patent Literature 27 (3GPP TS23.287)). RRC signaling in SL communication is also
referred to as PC5 RRC signaling. Examples of proposed techniques include
5 notification of UE capabilities between UEs that perform PC5 communication, and
notification of AS layer settings for performing V2X communication using PC5
communication.
[0116] FIG. 9 illustrates an exemplary connection configuration of mobile terminals in
10 the SL communication. In the example illustrated in FIG. 9, a UE 805 and a UE 806
exist within a coverage 803 of a base station 801. UL/DL communication 807 is
performed between the base station 801 and the UE 805. UL/DL communication 808
is performed between the base station 801 and the UE 806. SL communication 810 is
performed between the UE 805 and the UE 806. A UE 811 and a UE 812 exist outside
15 the coverage 803. SL communication 814 is performed between the UE 805 and the
UE 811. In addition, SL communication 816 is performed between the UE 811 and the
UE 812.
[0117] As an example of communication between the UE and the NW via a relay in the
20 SL communication, the UE 805 illustrated in FIG. 9 relays communication between the
UE 811 and the base station 801.
[0118] A configuration similar to that in FIG. 4 may be used for the UE that performs
relay. The relay processing in the UE will be described with reference to FIG. 4. The
25 relay processing by the UE 811 in the communication from the UE 805 to the base
station 801 will be described. Wireless signals from the base station UE 811 are
received by the antennas 307-1 to 307-4. The reception signal is converted from the
wireless reception frequency into a baseband signal in the frequency conversion unit
306, and demodulation is performed in the demodulation unit 308. The demodulation
30 unit 308 may perform weight calculation and multiplication. The demodulated data is
passed to the decoder unit 309, and decoding such as error correction is performed. The
decoded data is passed to the protocol processing unit 301, and protocol processing such
31
as MAC and RLC for use in communication with the UE 811, for example, an operation
such as removal of a header in each protocol, is performed. In addition, protocol
processing such as RLC and MAC for use in communication with the base station 801,
for example, adding a header in each protocol, is performed. In the protocol processing
5 unit 301 of the UE 811, protocol processing of the PDCP and the SDAP may be
performed. The data that has undergone the protocol processing is passed to the encoder
unit 304 and subjected to encoding such as error correction. Some data may be directly
output from the protocol processing unit 301 to the modulation unit 305 without being
subjected to encoding. The data encoded by the encoder unit 304 is subjected to
10 modulation in the modulation unit 305. The modulation unit 305 may perform
precoding for MIMO. The modulated data is converted into a baseband signal and then
output to the frequency conversion unit 306 to be converted into a wireless transmission
frequency. Thereafter, the transmission signals are transmitted from antennas 307-1 to
307-4 to the base station 801.
15
[0119] Although the example of the relay by the UE 811 in the communication from
the UE 805 to the base station 801 has been described above, similar processing is also
used in the relay of the communication from the base station 801 to the UE 811.
20 [0120] 5G base stations can support Integrated Access and Backhaul (IAB) (see Non
Patent Literature 2 and 20). A base station (hereinafter may be referred to as an IAB
base station) that supports IAB is constituted by an IAB donor CU that is a CU of a base
station that operates as an IAB donor providing the IAB function, an IAB donor DU that
is a DU of a base station that operates as an IAB donor, and an IAB node that is
25 connected to the IAB donor DU and to UE using a wireless interface. An F1 interface
is provided between the IAB node and the IAB donor CU (see Non Patent Literature 2).
[0121] An example connection of the IAB base station is illustrated in FIG. 10. An IAB
donor CU 901 is connected to an IAB donor DU 902. An IAB node 903 is connected
30 to the IAB donor DU 902 using a wireless interface. The IAB node 903 is connected to
an IAB node 904 using a wireless interface. That is, multi-stage connection of IAB
nodes may be performed. A UE 905 is connected to the IAB node 904 using a wireless
32
interface. A UE 906 may be connected to the IAB node 903 using a wireless interface,
or a UE 907 may be connected to the IAB donor DU 902 using a wireless interface. A
plurality of IAB donor DUs 902 may be connected to the IAB donor CU 901, a plurality
of IAB nodes 903 may be connected to the IAB donor DU 902, or a plurality of IAB
5 nodes 904 may be connected to the IAB node 903.
[0122] In the connection between the IAB donor DU and the IAB node and the
connection between the IAB nodes, a Backhaul Adaptation Protocol (BAP) layer is
provided (see Non Patent Literature 29). The BAP layer performs operations such as
10 routing of received data to the IAB donor DU and/or the IAB node, mapping to the RLC
channel, and the like (see Non Patent Literature 29).
[0123] As an example of the configuration of the IAB donor CU, a configuration similar
to that of the CU 215 is used.
15
[0124] As an example of the configuration of the IAB donor DU, a configuration similar
to that of the DU 216 is used. The protocol processing unit of the IAB donor DU
performs processing of the BAP layer, for example, adding a BAP header in downlink
data, routing to the IAB node, removing a BAP header in uplink data, and the like.
20
[0125] As an example of the configuration of the IAB node, a configuration without the
EPC communication unit 401, the other base station communication unit 402, and the
5GC communication unit 412 illustrated in FIG. 5 may be used.
25 [0126] The transmission/reception processing in the IAB node will be described with
reference to FIGS. 5 and 10. The transmission/reception processing of the IAB node
903 in communication between the IAB donor CU 901 and the UE 905 will be described.
In the uplink communication from the UE 905 to the IAB donor CU 901, a wireless
signal from the IAB node 904 is received by the antenna 408 (some or all of the antennas
30 408-1 to 408-4). The reception signal is converted from the wireless reception
frequency into a baseband signal in the frequency conversion unit 407, and
demodulation is performed in a demodulation unit 409. The demodulated data is passed
33
to a decoder unit 410, and decoding such as error correction is performed. The decoded
data is passed to the protocol processing unit 403, and protocol processing such as MAC
and RLC for use in communication with the IAB node 904, for example, an operation
such as removal of a header in each protocol, is performed. In addition, routing to the
5 IAB donor DU 902 using the BAP header is performed, and protocol processing such
as RLC and MAC for use in communication with the IAB donor DU 902, for example,
an operation of adding a header in each protocol, is performed. The data that has
undergone the protocol processing is passed to the encoder unit 405 and subjected to
encoding such as error correction. Some data may be directly output from the protocol
10 processing unit 403 to the modulation unit 406 without being subjected to encoding.
The encoded data is subjected to modulation in the modulation unit 406. The
modulation unit 406 may perform precoding for MIMO. The modulated data is
converted into a baseband signal and then output to the frequency conversion unit 407
to be converted into a wireless transmission frequency. Thereafter, transmission signals
15 are transmitted from the antennas 408-1 to 408-4 to the IAB donor DU 902. Similar
processing is performed in the downstream communication from the IAB donor CU 901
to the UE 905.
[0127] The IAB node 904 also performs transmission/reception processing similar to
20 that of the IAB node 903. In the protocol processing unit 403 of the IAB node 903, as
the processing of the BAP layer, for example, processing such as adding a BAP header
in uplink communication, routing to the IAB node 904, and removing a BAP header in
downstream communication, is performed.
25 [0128] In the NR-based communication system, positioning of the UE in the
RRC_INACTIVE state may be performed. The LMF may configure the positioning
signal setting so as to transmit the positioning signal (e.g. PRS) at a timing, e.g. onduration timing, at which the UE can receive the positioning signal. The LMF may
configure the positioning signal setting so as to transmit the positioning signal at the
30 paging timing of the UE.
[0129] The base station may change the paging timing. For example, the base station
34
may change the paging timing to match the positioning signal setting.
[0130] However, the paging timing is determined by using the identifier of the UE and
the parameter that is broadcast as system information. Therefore, a change in the paging
5 timing affects the paging timing of other UEs, leading to a problem that the
communication system is complicated.
[0131] The first embodiment discloses a method for solving this problem.
10 [0132] In order to solve the above problem, in the communication system according to
the present embodiment, the base station notifies the LMF of information related to a
timing at which the UE can receive a positioning signal.
[0133] The timing may be, for example, paging timing or On-duration (see Non Patent
15 Literature 2 (3GPP TS 38.300)) timing in DRX of the UE. The DRX may be, for
example, DRX (Connected mode DRX: C-DRX) in the RRC_CONNECTED state,
DRX (Idle mode DRX: I-DRX) in the RRC_INACTIVE and/or RRC_IDLE state, or
both of the foregoing.
20 [0134] For the notification from the base station to the LMF, NRPPa signaling may be
used, for example, NRPPa TRP INFORMATION RESPONSE, NRPPa POSITIONING
INFORMATION RESPONSE, or NRPPa POSITIONING INFORMATION UPDATE
signaling (see Non Patent Literature 30).
25 [0135] The following items (1) to (6) are disclosed as examples of information included
in the notification from the base station to the LMF.
[0136] (1) Information related to timing of paging of UE.
30 [0137] (2) Information related to frame timing.
[0138] (3) Information for use in deriving paging timing.
35
[0139] (4) Information for identifying UE.
[0140] (5) Information related to DRX of UE.
5
[0141] (6) Combinations of (1) to (5).
[0142] Information (1) described above may be, for example, a value of Paging Frame
(PF), a value of Paging Occasion (PO), a value of PDCCH monitoring occasion for use
10 in paging reception, or a combination of a plurality of the above. The LMF may change
the positioning signal setting using the information. Consequently, for example, the
amount of processing in changing the setting of the positioning signal
transmission/reception timing can be reduced.
15 [0143] As another example, information (1) described above may include information
related to the time of the paging timing. The information related to the time may include,
for example, the time at the start point of the paging timing, the time related to the end
point of the paging timing, information related to the duration of the paging timing, or
a plurality of pieces of information described above. The paging timing may be Paging
20 Frame (PF), Paging Occasion (PO), PDCCH monitoring occasion for use in paging
reception, or a combination of a plurality of the above. The LMF may change the
positioning signal setting using the information. Consequently, for example, the amount
of processing in changing the setting of the positioning signal transmission/reception
timing can further be reduced.
25
[0144] As an example of information (2) described above, the time at a predetermined
time point, for example, the time at a predetermined SFN boundary may be used. The
boundary may be the head of the SFN or the tail of the SFN. Other examples may
include the time at a predetermined subframe boundary, the time at a predetermined slot
30 boundary, or the time at a predetermined symbol boundary. The LMF may change the
positioning signal setting using the information. Consequently, for example, the amount
of processing in the LMF can be reduced.
36
[0145] Information (3) described above may include, for example, the identifier of the
UE, or parameters for use in determining the paging timing. The parameters may
include a part or all of the broadcast information from the base station, for example,
5 PCCH configuration information (PCCH-Config) disclosed in Non Patent Literature 19
(3GPP TS 38.331). The LMF may derive the paging timing of the UE by using the
information. Consequently, for example, the amount of processing required in the
notification from the UE and/or the base station can be reduced.
10 [0146] The identifier related to information (4) described above may be, for example,
UE_ID disclosed in Section 7.1 of Non Patent Literature 38 (3GPP TS 38.304), or may
be 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), 5G Temporary
Mobile Subscription Identifier (5G-TMSI), or 5G-GUTI disclosed in Non Patent
Literature 10 (3GPP TS 23.501). The LMF may derive the paging timing of the UE by
15 using the information. Consequently, for example, the amount of processing required
in the notification from the UE and/or the base station can be reduced.
[0147] Information (5) described above may include, for example, information related
to DRX cycle, on-duration start timing, and on-duration length, or a combination of the
20 above. The DRX information may include information related to C-DRX, information
related to I-DRX, or both of the foregoing. The information may include a
Discontinuous Reception (DRX) cycle (T) of the UE disclosed in Non Patent Literature
38 (3GPP TS 38.304), may include a total number of paging frames (N) in the cycle,
may include the number of paging occasions (Ns) in the PF, may include an offset
25 (PF_offset) that is used in the PF determination, or may include a first-PDCCHMonitoring OccasionOfPO in the PO. The LMF may change the positioning signal
setting using the information. Consequently, for example, the amount of processing in
the change of the positioning signal setting can be reduced.
30 [0148] The positioning signal setting may include information related to the time,
frequency, and/or resources of the code of the positioning signal. The setting may be,
for example, a setting related to the PRS or a setting related to the SRS. The settings
37
related to the PRS and/or the SRS may include the parameters disclosed in Non Patent
Literature 31 (3GPP TS 37.355) or may include the parameters disclosed in Non Patent
Literature 19 (3GPP TS 38.331). The setting of the positioning signal may include, for
example, information related to at least one or more of the cycle, offset, duration,
5 frequency resource, and code sequence.
[0149] The positioning signal setting may include information related to the target UE.
The base station may use the information to determine whether to transmit and/or
receive the positioning signal. For example, when the base station does not cover the
10 target UE, the base station may not transmit and receive the positioning signal.
Consequently, for example, the power consumption of the base station can be reduced.
[0150] The LMF may request the information from the base station. The notification
from the base station to the LMF may be performed in response to the request from the
15 LMF. For the request from the LMF, NRPPa signaling, for example, signaling of
NRPPa TRP INFORMATION REQUEST may be used, or signaling of NRPPa
POSITIONING INFORMATION REQUEST may be used (see Non Patent Literature
30). A new NRPPa signaling may be provided. The new NRPPa signaling may be used.
The request from the LMF may include information related to the UE, e.g. the identifier
20 of the UE.
[0151] The LMF may use the information to change the PRS setting. The LMF may
notify the base station of the changed PRS setting. For the notification from the LMF
to the base station, for example, NRPPa signaling may be used. The base station may
25 give the UE broadcast or notification of the changed PRS setting. As another example,
the LMF may notify the UE of the changed PRS setting. For the notification from the
LMF to the UE, for example, LPP signaling may be used.
[0152] The LMF may acquire information related to the base station that covers the UE.
30 Consequently, for example, even when the UE performs cell reselection, the LMF can
transmit and receive the NRPPa signaling to and from the base station that covers the
UE, and as a result, the positioning of the UE can be promptly executed.
38
[0153] The LMF may acquire information related to TA and/or RNA of the base station
that covers the UE. The LMF may acquire information related to base stations that
belong to the TA and/or RNA. The LMF may select the positioning base station by
5 using the notification. Consequently, for example, the UE can promptly execute paging
associated with cell reselection.
[0154] The LMF may request the AMF for information related to the base station that
covers the UE. The AMF may notify the LMF of information related to the base station
10 that covers the UE. For example, the AMF may acquire information related to the base
station that covers the UE by using paging.
[0155] As another example, the LMF may inquire of the base station whether the base
station covers the UE. The base station may notify the LMF of information related to
15 whether the base station covers the UE, or information related to the base station that
covers the UE. For example, the base station may acquire information related to the
base station that covers the UE by using paging.
[0156] FIGS. 11 and 12 are diagrams illustrating an example of a positioning sequence
20 related to the UE in RRC_INACTIVE. FIG. 11 illustrates the first half of the sequence,
and FIG. 12 illustrates the second half of the sequence. FIGS. 11 and 12 illustrate an
example of positioning in which a positioning request source device makes a location
information request, that is, UE-assisted positioning (positioning in which the LMF or
the like performs position calculation using assistance information (e.g. positioning
25 signal reception result) from the UE) (see Non Patent Literature 25) according to a
location information request (Mobile-Terminated Location Request: MT-LR) (see Non
Patent Literature 25) terminated in the UE. In the example illustrated in FIGS. 11 and
12, a case where Downlink Time Difference of Arrival: (DL-TDOA) (see Non Patent
Literature 24) is used as a positioning method for the UE will be described.
30
[0157] In procedure 1105 illustrated in FIG. 11, a positioning request to the LMF is
made from an external device. In step ST1110, a positioning request for the UE occurs
39
in the external device. In step ST1112, the external device transmits a positioning
request to a gateway mobile location center (GMLC) (see Non Patent Literature 25).
The request may include information related to the UE, for example, the identifier of
the UE.
5
[0158] In step ST1114 illustrated in FIG. 11, the GMLC inquires of the UDM about the
NW address of the AMF. In step ST1116, the UDM notifies the GMLC of the NW
address of the AMF.
10 [0159] In step ST1118 illustrated in FIG. 11, the GMLC transfers the positioning
request from the external device to the AMF. The request may include information
related to the UE, for example, the identifier of the UE. In step ST1120, the AMF
transfers the request to the LMF. The request transferred from the AMF to the LMF
may include information related to the UE, for example, the identifier of the UE.
15
[0160] In procedure 1125 illustrated in FIG. 11, the operation of acquiring the
positioning capability of the UE by the LMF is performed. In steps ST1127 and ST1129,
a positioning capability request is made from the LMF to the UE. In the example
illustrated in FIG. 11, the request is made via the AMF. Step ST1127 indicates the
20 request from the LMF to the AMF, and step ST1129 indicates the request from the AMF
to the UE. In steps ST1127 and ST1129, for example, signaling of LPP request
capabilities is used. In steps ST1131 and ST1133, the UE notifies the LMF of the
positioning capability. In the example illustrated in FIG. 11, the notification is given
via the AMF. Step ST1131 indicates the notification from the UE to the AMF, and step
25 ST1133 indicates the notification from the AMF to the LMF. In steps ST1131 and
ST1133, for example, signaling of LPP provide capabilities is used.
[0161] In step ST1135 illustrated in FIG. 11, the LMF requests information related to
the resources of positioning signals from the base station. For the request, for example,
30 signaling of NRPPa TRP INFORMATION REQUEST (see Non Patent Literature 30)
may be used. The request in step ST1135 may be made to a positioning base station
which is a base station that is used for positioning of the UE. The request may be made
40
to a plurality of base stations.
[0162] In step ST1135, information related to the UE, for example, the identifier of the
UE, may be included, or a request for information related to the positioning signal
5 reception timing of the UE may be included. The request for information related to the
positioning signal reception timing of the UE may be, for example, a request for DRXrelated information of the UE or a request for information related to the paging timing
of the UE. The signaling in step ST1135 including the information related to the UE
and/or the request for the information related to the positioning signal reception timing
10 of the UE may be performed on the serving base station of the UE.
[0163] In step ST1136 illustrated in FIG. 11, the base station notifies the LMF of
information related to the resources of positioning signals. For the notification, for
example, signaling of NRPPa TRP INFORMATION RESPONSE (see Non Patent
15 Literature 30) may be used. The signaling of step ST1136 may be transmitted by the
serving base station of the UE, by a neighboring base station, or by both of the foregoing.
[0164] The information to be provided by the base station to the LMF in step ST1136
may include information related to the positioning signal reception timing of the UE.
20 The information may be, for example, DRX-related information of the UE or
information related to the paging timing of the UE. The information may include the
above-described information items (1) to (6). The signaling in step ST1136 including
the information may be performed by the serving base station of the UE.
25 [0165] In step ST1137 illustrated in FIG. 11, the LMF determines the setting of the
positioning signal, for example, PRS. In step ST1138, the LMF requests the determined
positioning signal setting from the base station. For the request, for example, signaling
of NRPPa PRS CONFIGURATION REQUEST (see Non Patent Literature 30) may be
used. The base station configures the positioning signal setting using the setting
30 information included in the request received in step ST1138. In step ST1139, the base
station gives the LMF a response to step ST1138. For the response, for example,
signaling of NRPPa PRS CONFIGURATION RESPONSE (see Non Patent Literature
41
30) may be used. In step ST1141, the base station gives the UE broadcast or notification
of system information related to the positioning signal. The system information may
include the positioning signal setting.
5 [0166] In procedure 1145 illustrated in FIG. 12, processing from the positioning request
to the position calculation is performed. In steps ST1146 and ST1147, the LMF requests
the UE for positioning-related information. In the example illustrated in FIG. 12, the
request is made via the AMF. Step ST1146 indicates the request from the LMF to the
AMF, and step ST1147 indicates the request from the AMF to the UE. For the request,
10 for example, signaling of LPP Request Location Information (see Non Patent Literature
31) may be used. The request may include information related to the positioning method,
or may include information related to the resources of the positioning signal that the
base station transmits to the UE.
15 [0167] In step ST1149 illustrated in FIG. 12, the base station transmits a positioning
signal to the UE. For the signal, for example, a positioning reference signal (PRS) may
be used. In step ST1151, the UE measures the positioning signal from the base station.
[0168] In steps ST1153 and ST1155 illustrated in FIG. 12, the UE notifies the LMF of
the positioning signal reception result. The notification is given via the AMF. Step
20 ST1153 indicates the notification from the UE to the AMF, and step ST1155 indicates
the notification from the AMF to the LMF. Signaling of LPP Provide Location
Information (see Non Patent Literature 31) may be used for the notification in step
ST1153 and/or step ST1155.
25 [0169] In step ST1157 illustrated in FIG. 12, the LMF calculates the position of the UE.
The LMF may perform the calculation using the positioning signal reception result
provided in step ST1155.
[0170] In procedure 1165 illustrated in FIG. 12, processing of notification of the
30 positioning result is performed.
[0171] In step ST1167 illustrated in FIG. 12, the LMF notifies the AMF of the
42
positioning result. In step ST1169 illustrated in FIG. 12, the AMF notifies the GMLC
of the positioning result. In step ST1171, the GMLC notifies the external device of the
positioning result.
5 [0172] FIGS. 11 and 12 illustrate the example in which the positioning signal setting is
broadcast to the UE using the system information. However, the UE may be
individually notified of the positioning signal setting by the LMF. The notification from
the LMF to the UE may be given via the AMF. For the notification from the LMF to
the UE, for example, signaling of LPP Provide Assistance Data (Non Patent Literature
10 31) may be used. Consequently, for example, the UE can receive the setting without
waiting for the broadcast timing, and as a result, the UE can promptly acquire the
positioning signal setting.
[0173] Although the case where DL-TDOA is used is illustrated in FIGS. 11 and 12,
15 Downlink Angle of Departure (DL-AoD), NR Enhanced Cell ID (NR E-CID), or
another positioning method may be used. For example, in positioning using DL-AoD,
power consumption of the UE can also be reduced.
[0174] Although FIGS. 11 and 12 disclose the case where the positioning method in
20 which the UE receives the positioning signal is used, a positioning method in which the
UE transmits the positioning signal may be used, or a positioning method in which the
UE performs both transmission and reception of the positioning signal, for example,
multi-round trip time (Multi-RTT), may be used. Consequently, for example, the
positioning accuracy can be improved.
25
[0175] Although the example of the UE-assisted positioning is illustrated in FIGS. 11
and 12, this may be applied to UE-based positioning (positioning in which the UE
performs position calculation) (see Non Patent Literature 25) or may be applied to NWassisted positioning (positioning in which an NW-side device, for example, a base
30 station, provides notification of the positioning signal reception result) (see Non Patent
Literature 25). Consequently, for example, a similar effect can be obtained in UE-based
positioning and NW-assisted positioning.
43
[0176] Although the example of MT-LR is illustrated in FIGS. 11 and 12, this may be
applied to a location information request (mobile-originated location request: MO-LR)
(see Non Patent Literature 25) initiated in the UE, or may be applied to a location
5 information request (network-initiated location request: NI-LR) (see Non Patent
Literature 25) initiated in a NW-side device, for example, the AMF. A similar effect
can be obtained in MO-LR and/or NI-LR.
[0177] Paging for positioning signal measurement requests may be provided. For
10 example, paging may include information indicating that a positioning signal
measurement request is included. The paging may include information related to the
resource including information related to the positioning signal measurement request.
For example, instead of step ST1147 illustrated in FIG. 12, the paging may be used, or
notification of the information from the AMF to the base station and/or signaling of the
15 instruction for the paging may be used. By means of the information, the UE may
recognize the start of positioning, or may acquire a positioning signal measurement
request. Consequently, for example, the UE can promptly start the positioning signal
reception.
20 [0178] The UE may transmit the positioning signal reception result (for example, step
ST1153 in FIG. 12) by small data transmission (SDT). The small data transmission may
be performed, for example, by using message 3 and/or message A in the random access.
The UE need not transition from the RRC_IDLE or RRC_INACTIVE state to the
RRC_CONNECTED state. Consequently, for example, the power consumption of the
25 UE can be reduced.
[0179] Disclosed below are other solutions. The UE notifies the LMF of information
related to a timing at which a positioning signal can be received. The UE may include
the information in existing LPP signaling to give the notification. For example, the
30 information may be included in the positioning-related capability to be provided by the
UE to the LMF. For example, signaling of LPP provide capabilities (Non Patent
Literature 31) may be used to provide notification of the positioning-related capability.
44
[0180] The information to be provided by the UE to the LMF may be similar to the
above-described information items (1) to (6).
[0181] FIG. 13 is a diagram illustrating a first other example of a positioning sequence
5 related to the UE in RRC_INACTIVE. FIG. 13 illustrates an example of UE-assisted
positioning according to MT-LR. In the example illustrated in FIG. 13, a case where
DL-TDOA is used as the UE positioning method will be described. In FIG. 13,
processes similar to those in FIGS. 11 and 12 are denoted by the same reference signs,
and descriptions already provided are omitted.
10
[0182] In procedure 1225 illustrated in FIG. 13, the operation of acquiring the
positioning capability of the UE by the LMF is performed. Steps ST1127 and ST1129
are similar to those in FIG. 11. In steps ST1231 and ST1233, the UE notifies the LMF
of the positioning capability. In the example illustrated in FIG. 13, the notification is
15 given via the AMF. Step ST1231 indicates the notification from the UE to the AMF,
and step ST1233 indicates the notification from the AMF to the LMF. In steps ST1231
and ST1233, for example, signaling of LPP provide capabilities is used. Steps ST1231
and ST1233 include information related to the positioning signal reception timing in the
UE.
20
[0183] In step ST1235 illustrated in FIG. 13, the LMF requests information related to
the resources of positioning signals from the base station. For the request, for example,
signaling of NRPPa TRP INFORMATION REQUEST (see Non Patent Literature 30)
may be used. The request in step ST1235 may be made to the positioning base station.
25 The request may be made to a plurality of base stations.
[0184] In step ST1236 illustrated in FIG. 13, the base station notifies the LMF of
information related to the resources of positioning signals. For the notification, for
example, signaling of NRPPa TRP INFORMATION RESPONSE (see Non Patent
30 Literature 30) may be used. The signaling of step ST1236 may be transmitted by the
serving base station of the UE, by a neighboring base station, or by both of the foregoing.
45
[0185] Step ST1137 to procedure 1165 illustrated in FIG. 13 are similar to those in
FIGS. 11 and 12.
[0186] FIG. 13 illustrates the example in which the positioning signal setting is
5 broadcast to the UE using the system information. However, the UE may be
individually notified of the positioning signal setting by the LMF. The notification from
the LMF to the UE may be given via the AMF. For the notification from the LMF to
the UE, for example, signaling of LPP Provide Assistance Data (Non Patent Literature
31) may be used. Consequently, for example, the UE can receive the setting without
10 waiting for the broadcast timing, and as a result, the UE can promptly acquire the
positioning signal setting.
[0187] Although the case where DL-TDOA is used is illustrated in FIG. 13, other
positioning methods may be used as in FIGS. 11 and 12. Other positioning methods
15 may include a positioning method in which the UE transmits a positioning signal. A
similar effect can be obtained in other positioning methods.
[0188] In FIG. 13, UE-based positioning may be used, or NW-assisted positioning may
be used. In addition, in FIG. 13, positioning associated with MO-LR and/or positioning
20 associated with NI-LR may be used. Consequently, for example, a similar effect can be
obtained in these positioning methods.
[0189] As another example, the UE may include the information in the request to change
the positioning signal setting to give the notification to the LMF. The request to change
25 the positioning signal setting from the UE to the LMF may be, for example, on-demand
PRS request (see Non Patent Literatures 40 and 41). For the request, for example,
signaling of LPP request assistance data (see Non Patent Literature 31) may be used.
The information that the UE includes in the request to give the notification to the LMF
may be similar to the above-described information items (1) to (6).
30
[0190] FIG. 14 is a diagram illustrating a second other example of a positioning
sequence related to the UE in RRC_INACTIVE. FIG. 14 illustrates an example of UE-
46
assisted positioning according to MT-LR. In the example illustrated in FIG. 14, a case
where DL-TDOA is used as the UE positioning method will be described. In FIG. 14,
processes similar to those in FIGS. 11, 12, and 13 are denoted by the same reference
signs, and descriptions already provided are omitted.
5
[0191] Procedures 1105 and 1125 illustrated in FIG. 14 are similar to those in FIG. 11.
[0192] Steps ST1235 and ST1236 illustrated in FIG. 14 are similar to those in FIG. 13.
10 [0193] Steps ST1137 to ST1141 illustrated in FIG. 14 are similar to those in FIG. 11.
[0194] In steps ST1335 and ST1336 illustrated in FIG. 14, the UE requests the LMF to
change the positioning signal setting. In the example illustrated in FIG. 14, the request
is made via the AMF. Step ST1335 indicates the request from the UE to the AMF, and
15 step ST1336 indicates the request from the AMF to the LMF. For steps ST1335 and
ST1336, for example, signaling of LPP request assistance data is used. The request may
include information related to the positioning signal reception timing in the UE, for
example, the above-described information items (1) to (6). The request may include
information indicating on-demand PRS request. In step ST1337, the LMF configures
20 the positioning signal setting. The information included in step ST1336 may be used
for the setting.
[0195] In steps ST1338 to ST1341 illustrated in FIG. 14, operations similar to those in
steps ST1138 to ST1141 are performed.
25
[0196] Procedures 1145 and 1165 illustrated in FIG. 14 are similar to those in FIG. 12.
[0197] FIG. 14 illustrates the example in which the positioning signal setting is
broadcast to the UE using the system information. However, the UE may be
30 individually notified of the positioning signal setting by the LMF. The notification from
the LMF to the UE may be given via the AMF. For the notification from the LMF to
the UE, for example, signaling of LPP Provide Assistance Data (Non Patent Literature
47
31) may be used. Consequently, for example, the UE can receive the setting without
waiting for the broadcast timing, and as a result, the UE can promptly acquire the
positioning signal setting.
5 [0198] Although the case where DL-TDOA is used is illustrated in FIG. 14, other
positioning methods may be used as in FIGS. 11 and 12. Other positioning methods
may include a positioning method in which the UE transmits a positioning signal. A
similar effect can be obtained in other positioning methods.
10 [0199] In FIG. 14, UE-based positioning may be used, or NW-assisted positioning may
be used. In addition, in FIG. 13, positioning associated with MO-LR and/or positioning
associated with NI-LR may be used. Consequently, for example, a similar effect can be
obtained in these positioning methods.
15 [0200] Disclosed below are other solutions. A positioning signal reception timing is
newly provided. For example, the timing may be newly provided in addition to the
paging timing of the UE. The UE may receive the positioning signal at the positioning
signal reception timing and/or the paging timing. Consequently, for example, flexibility
in the communication system can be improved.
20
[0201]The LMF may notify the UE of information related to the newly provided timing.
The notification may be given using LPP signaling, for example, signaling of LPP
provide assistance data, or may be given using system information via NRPPa signaling.
25 [0202] Information related to the timing may include, for example, information related
to the cycle or information related to the offset with respect to the cycle.
[0203] The timing may be fixed in RNA. Consequently, for example, the fixed timing
can be used in the cell reselection destination in the cell reselection of the UE, and as a
30 result, it is not necessary to change the setting of the timing according to the cell
reselection. As another example, the timing may be fixed in the tracking area.
Consequently, for example, the same effect as described above can be obtained even
48
when cell reselection to the outside of RNA occurs.
[0204] The LMF may acquire information related to TA and/or RNA of the base station
that covers the UE. The LMF may acquire information related to base stations that
5 belong to the TA and/or RNA. The base station may notify the LMF of the information.
[0205] The timing may be provided individually for each UE. Consequently, for
example, the flexibility related to the setting of the timing can be improved. As another
example, the timing may be common among UEs. Consequently, for example, the
10 complexity related to the setting of the timing can be avoided.
[0206] The UE may start the reception operation of the positioning signal at the newly
provided timing in response to notification or broadcast of information related to the
timing. Consequently, for example, complexity in the reception operation of the UE
15 can be avoided. As another example, the UE may start the reception operation in
response to reception of a positioning signal reception request, for example, signaling
of LPP request location information. Consequently, for example, the power
consumption of the UE can be reduced.
20 [0207] Disclosed below are other solutions. The base station configures the positioning
signal setting. The base station may configure the positioning signal setting regardless
of the positioning signal setting provided from the LMF. The base station may notify
the LMF of the determined setting. For the notification, for example, NRPPa signaling
may be used. The LMF may reflect or reject the positioning signal setting provided
25 from the base station, or reflect the positioning signal setting partially changed. As an
example of the partial change, the cycle may be changed, for example, changed to oneinteger or an integer multiple, or the offset may be changed with respect to the cycle.
The partial change can improve the flexibility of the positioning procedure in the
communication system, for example. The LMF may notify the base station of
30 information related to reflection, rejection, and partial change of the setting.
[0208] Disclosed below are other solutions. The base station transmits a positioning
49
signal at a timing at which the UE can receive the positioning signal. The transmission
may be executed regardless of the positioning signal setting. The base station may
transmit a positioning signal at the paging timing of the UE. The base station may
transmit a positioning signal within the range of time/frequency resources of paging of
5 the UE, for example, within the range of time/frequency resources of the PDCCH and/or
the PDSCH of the paging. As another example, the base station may transmit a
positioning signal instead of the paging of the UE. The base station may transmit a
positioning signal in a slot in which paging is transmitted. Consequently, for example,
wireless resources in the communication system can be saved.
10
[0209] In the foregoing resources, rate matching may be performed. For example, rate
matching may be performed in a slot in which a positioning signal is transmitted. The
base station may notify the UE that the rate matching is performed, or as another
example, the UE may perform decoding on the assumption that the rate matching is
15 performed in the resource on which the positioning signal is transmitted. Consequently,
for example, the reliability of reception of time/frequency resources including the
positioning signal can be improved in the UE.
[0210] Setting that the positioning signal is included in the resource may be configured
20 for the UE. The setting may be configured by the base station, the AMF, or the LMF.
For example, the base station may notify the UE or the LMF of the setting. The AMF
may notify the base station, the UE, or the LMF of the setting. The LMF may notify the
AMF, the base station, or the UE of the setting.
25 [0211] The PRS may not be mapped to a resource (e.g. Resource Element (RE)) to
which the DMRS is allocated. Consequently, for example, deterioration in the
demodulation performance of downlink signals in the UE can be prevented.
[0212] The DMRS may not be mapped to a resource (e.g. RE) to which the PRS is
30 allocated. Consequently, for example, deterioration in the positioning accuracy can be
prevented.
50
[0213] In a case where the DMRS resource and the PRS resource collide, which RS is
to be mapped may be determined by a standard, by the base station, by the AMF, or by
the LMF. The base station may notify the UE or the LMF of the setting. The AMF may
notify the base station, the UE, or the LMF of the setting. The LMF may notify the
5 AMF, the base station, or the UE of the setting. For example, determining by the base
station, the AMF, and/or the LMF can improve flexibility in the communication system.
[0214] Disclosed below are other solutions. The positioning signal setting may include
setting for conformity to paging. For example, a value indicating conformity to paging
10 may be included as an option that can be taken for the setting value of the cycle, the
offset, and/or the duration of the positioning signal. Consequently, for example, the
complexity related to the positioning signal setting can be avoided. An explicit setting
value may be provided for any one of the cycle and the offset of the positioning signal.
Consequently, for example, the flexibility related to the positioning signal setting can
15 be improved. The information may include information for identifying the UE.
Consequently, for example, it is possible to prevent malfunction such as transmission of
a positioning signal in conformity to the paging timing of another UE.
[0215] Disclosed below are other solutions. The paging timing of the UE is changed.
20 For example, the UE-ID is changed.
[0216] The UE may request the AMF to change the identifier of the UE itself. The
request may include one or more UE identifiers as change candidates. The request may
include information related to the reason. The information may be, for example,
25 matching the paging timing and the positioning signal reception timing. NAS signaling
may be used for the request. A new NAS signaling may be provided. For example,
signaling of UE configuration update request from the UE to the AMF may be provided.
The UE may notify the AMF using the newly provided NAS signaling.
30 [0217] The request may be made by the base station. The base station may request the
AMF to change the identifier of the UE. The request may include one or more UE
identifiers as change candidates. The request may include information related to the
51
reason. The information may be, for example, matching the paging timing and the
positioning signal reception timing. For the request, for example, signaling in the N2
interface may be used. New signaling, for example, signaling of N2UE configuration
update request may be provided and used. The identifier of the UE may be, for example,
5 UE_ID disclosed in Section 7.1 of Non Patent Literature 38 (3GPP TS 38.304), or may
be 5G S-Temporary Mobile Subscription Identifier (5S-TMSI), 5G Temporary Mobile
Subscription Identifier (5G-TMSI), or 5G-GUTI disclosed in Non Patent Literature 10
(3GPP TS 23.501). The AMF may change the identifier of the UE by using the signaling

WE CLAIM:
[Claim 1] A communication system to which a fifth-generation wireless access
system is applied, the communication system comprising:
5 a network-side device equipped with a location management function of the
fifth-generation wireless access system; and
a base station, wherein
in a case where a positioning request for a communication terminal connected
to the base station occurs,
10 the base station to which a positioning target terminal that is a communication
terminal to be subjected to positioning is connected notifies the network-side device of
information related to a timing at which the positioning target terminal is able to receive
a positioning signal, and
the network-side device determines setting contents related to a
15 transmission/reception timing of a positioning signal based on the information provided
from the base station, and notifies the base station that transmits the positioning signal
and the positioning target terminal of the setting contents determined.
[Claim 2] A communication system to which a fifth-generation wireless access
20 system is applied, the communication system comprising:
a network-side device equipped with a location management function of the
fifth-generation wireless access system; and
a base station, wherein
in a case where a positioning request for a communication terminal connected
25 to the base station occurs,
a positioning target terminal that is a communication terminal to be subjected to
positioning notifies the network-side device of information related to a timing at which
the positioning target terminal is able to receive a positioning signal, and
the network-side device determines setting contents related to a
30 transmission/reception timing of a positioning signal based on the information provided
from the positioning target terminal, and notifies the base station that transmits the
positioning signal and the positioning target terminal of the setting contents determined.
[Claim 3] The communication system according to claim 1 or 2, wherein
35 in a case where the location management function does not grasp a base station
that covers a communication terminal that is a target of the positioning request at a time
that the positioning request occurs,
an access and mobility management function of the fifth-generation wireless
access system notifies the location management function of information related to a base
40 station that covers a communication terminal that is a target of the positioning request
that has occurred.
81
[Claim 4] The communication system according to any one of claims 1 to 3,
wherein
in a case where cell reselection by the positioning target terminal occurs,
5 a base station constituting a reselected cell notifies the network-side device of
information indicating that the base station covers the positioning target terminal and
information related to a timing at which the positioning target terminal is able to receive
a positioning signal, and
the network-side device changes the setting contents based on the information
10 provided from the base station constituting the cell reselected by the positioning target
terminal, and notifies the base station that transmits the positioning signal and the
positioning target terminal of the setting contents changed.
[Claim 5] The communication system according to any one of claims 1 to 4,
15 wherein
the network-side device acquires information related to capability possessed by
the positioning target terminal, and determines the setting contents based on the
information acquired and information related to a timing at which the positioning target
terminal is able to receive a positioning signal.
20
[Claim 6] The communication system according to any one of claims 1 to 5,
wherein
the setting contents include information related to a beam that the positioning
target terminal is able to receive.