U.S. patent application number 17/827800 was filed with the patent office on 2022-09-15 for telecommunications apparatus and methods.
This patent application is currently assigned to Sony Group Corporation. The applicant listed for this patent is Sony Group Corporation. Invention is credited to Anders BERGGREN, Jussi Tapani KAHTAVA, Peter C. KARLSSON, Dimitris KOULAKIOTIS, Rickard LJUNG, Brian Alexander MARTIN, Lars NORD.
Application Number | 20220295501 17/827800 |
Document ID | / |
Family ID | 1000006366372 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220295501 |
Kind Code |
A1 |
MARTIN; Brian Alexander ; et
al. |
September 15, 2022 |
TELECOMMUNICATIONS APPARATUS AND METHODS
Abstract
A method of operating a terminal device and a base station in a
wireless telecommunications system to communicate with one another
using a primary component carrier operating on radio resources
within a first frequency band and a secondary component carrier
operating on radio resources within a second frequency band. The
terminal device makes measurements of radio usage in the second
frequency band, e.g. by other devices which are not part of the
wireless telecommunications system but which can also use radio
resources within the second frequency band. The terminal device
transmits an indication of the measurements to the base station,
and on the basis if this the base station establishes a
configuration setting for the secondary component carrier, for
example in terms of frequency resources to use for the secondary
component carrier.
Inventors: |
MARTIN; Brian Alexander;
(Basingstoke, GB) ; KOULAKIOTIS; Dimitris;
(Basingstoke, GB) ; KAHTAVA; Jussi Tapani;
(Basingstoke, GB) ; LJUNG; Rickard; (Helsingborg,
SE) ; BERGGREN; Anders; (Lund, SE) ; KARLSSON;
Peter C.; (Lund, SE) ; NORD; Lars; (Lund,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Group Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Sony Group Corporation
Tokyo
JP
|
Family ID: |
1000006366372 |
Appl. No.: |
17/827800 |
Filed: |
May 30, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16986261 |
Aug 6, 2020 |
11350426 |
|
|
17827800 |
|
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|
|
16173850 |
Oct 29, 2018 |
10772105 |
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|
16986261 |
|
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|
15305999 |
Oct 21, 2016 |
10129897 |
|
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PCT/EP2015/061298 |
May 21, 2015 |
|
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|
16173850 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 24/10 20130101;
H04W 72/1289 20130101; H04W 72/0486 20130101; H04W 84/12 20130101;
H04W 72/085 20130101; H04W 28/0231 20130101; H04L 5/006 20130101;
H04L 5/0087 20130101; H04L 5/001 20130101; H04W 72/042 20130101;
H04W 36/0072 20130101; H04L 5/0096 20130101; H04W 72/0453 20130101;
H04W 84/042 20130101; H04W 36/0058 20180801; H04W 72/1252 20130101;
H04W 16/14 20130101; H04W 24/02 20130101; H04W 72/1231 20130101;
H04W 28/0205 20130101; H04W 76/38 20180201 |
International
Class: |
H04W 72/08 20060101
H04W072/08; H04W 76/38 20060101 H04W076/38; H04L 5/00 20060101
H04L005/00; H04W 16/14 20060101 H04W016/14; H04W 72/12 20060101
H04W072/12; H04W 28/02 20060101 H04W028/02; H04W 24/02 20060101
H04W024/02; H04W 36/00 20060101 H04W036/00; H04W 72/04 20060101
H04W072/04; H04W 24/10 20060101 H04W024/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2014 |
EP |
14171285.1 |
Claims
1: Circuitry of a terminal device that communicates with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the circuitry comprising: a
transceiver; and control circuitry, the control circuitry and the
transceiver configured together to: receive an indication of a
configuration setting for the secondary component carrier from the
network infrastructure equipment; establish a validity period for
the configuration setting; and receive data from the network
infrastructure equipment, using the primary component carrier and
the secondary component carrier in accordance with the
configuration setting, during the validity period for the
configuration setting.
2-3. (canceled)
4: The circuitry of claim 1, wherein the control circuitry and the
transceiver are further configured to: measure a radio usage in the
second band; and transmit an indication of the measurements of
radio usage in the second band.
5: The circuitry of claim 4, wherein the control circuitry and the
transceiver are further configured to: determine whether the
validity period has expired; and in a case that the validity period
is determined to have expired, measure the radio usage in the
second band and transmit an indication of the measurements of radio
usage in the second band.
6: The circuitry of claim 1, wherein the control circuitry and the
transceiver are further configured to: determine whether the
validity period has expired; and in a case that the validity period
is determined have expired, release the configuration setting.
7: The circuitry of claim 1, wherein the control circuitry and the
transceiver are further configured to: receive another indication,
of an updated configuration setting for the second band, after the
validity period has expired; establish another validity period for
the updated configuration setting for the second band; and receive
data using the second band operating in accordance with the updated
configuration setting during the another validity period for the
updated configuration setting.
8: The circuitry of claim 1, wherein the control circuitry and the
transceiver are further configured to: perform channel quality
measurements for the second band; determine whether the channel
quality measurements indicate a channel quality is below a
threshold channel quality; and in a case that the channel quality
measurements are determined to indicate that the channel quality is
below the threshold channel quality, measure a radio usage in the
second band and transmit an indication of the measurements of radio
usage in the second band.
9: The circuitry of claim 8, wherein the control circuitry and the
transceiver are further configured to: receive another indication
of an updated configuration setting for the second band after
transmitting the indication of the measurements of radio usage in
the second band; establish another validity period for the updated
configuration setting for the second band; and receive data using
the second band operating in accordance with the updated
configuration setting for the second band during the another
validity period for the updated configuration setting.
10: The circuitry of claim 1, wherein the control circuitry and the
transceiver are further configured to: receive a request to provide
an indication of radio usage in the second band; measure a radio
usage in the second band; and transmit the indication of the
measurements of radio usage in the second band in response
thereto.
11: The circuitry of claim 10, wherein the control circuitry and
the transceiver are further configured to: receive another
indication of an updated configuration setting for the second band
after transmitting the indication of the measurements of radio
usage in the second band in response to receiving the request;
establish another validity period for the updated configuration
setting for the second band; and receive data using the second band
operating in accordance with the updated configuration setting for
the second band during the another validity period for the updated
configuration setting.
12: The circuitry of claim 4, wherein the indication of the
measurements of radio usage in the second band is transmitted using
transmission resources in the first band.
13: The circuitry of claim 4, wherein the indication of the
measurements of radio usage in the second band is transmitted using
radio resource control (RRC) signaling.
15: The circuitry of claim 1, wherein the indication of the
configuration setting for the second band is received using
transmission resources in the first band.
16: The circuitry of claim 1, wherein the indication of the
configuration setting for the second band is received using radio
resource control (RRC) signaling.
17: The circuitry of claim 4, wherein communications are received
by the terminal device operating in accordance with a first
wireless communications operating standard, and the measurements of
radio usage in the second band are made by the terminal device
operating in accordance with a second wireless communications
operating standard that is different from the first wireless
communications operating standard.
18: The circuitry of claim 17, wherein the first wireless
communications operating standard is a cellular telecommunications
operating standard and the second wireless communications operating
standard is a non-cellular telecommunications operating
standard.
19: The circuitry of claim 1, wherein the validity period is
established in accordance with an operating standard for a wireless
telecommunications system.
20: A method of operating network infrastructure equipment in a
wireless telecommunications system for communicating with a
terminal device using a primary component carrier operating on
radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, the method comprising: determining a configuration
setting for the secondary component carrier based on radio usage in
the second frequency band; establishing a validity period for the
configuration setting; transmitting an indication of the
configuration setting for the secondary component carrier to the
terminal device; transmitting data to the terminal device, using
the primary component carrier and the secondary component carrier
in accordance with the configuration setting, during the validity
period for the configuration setting.
21: The method of claim 20, further comprising: determining whether
the validity period for the configuration setting for the secondary
component carrier has expired; and in a case that the validity
period is determined to have expired, determining a new
configuration setting based on measured radio usage in the second
frequency band and establishing another validity period for the new
configuration setting.
22: Network infrastructure equipment for use in a wireless
telecommunications system for communicating with a terminal device
using a primary component carrier operating on radio resources
within a first frequency band and a secondary component carrier
operating on radio resources within a second frequency band, the
network infrastructure equipment comprising: processing circuitry
configured to: determine a configuration setting for the secondary
component carrier based on radio usage in the second frequency
band; establish a validity period for the configuration setting;
transmit an indication of the configuration setting for the
secondary component carrier to the terminal device; transmit data
to the terminal device, using the primary component carrier and the
secondary component carrier in accordance with the configuration
setting, during the validity period for the configuration setting.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 16/986,261, filed Aug. 6, 2020, which is a
continuation of U.S. application Ser. No. 16/173,850, filed Oct.
29, 2018 (now U.S. Pat. No. 10,772,105), which is a continuation of
U.S. application Ser. No. 15/305,999, filed Oct. 21, 2016 (now U.S.
Pat. No. 10,129,897), which is based on PCT filing
PCT/EP2015/061298, filed May 21, 2015, and claims priority to
European Patent Application 14171285.1, filed in the European
Patent Office on Jun. 5, 2014, the entire contents of all of each
are incorporated herein by reference.
BACKGROUND
Field
[0002] The present disclosure relates to mobile communications
networks and methods for communicating data using mobile
communications networks, infrastructure equipment for mobile
communications networks, communications devices for communicating
data via mobile communications networks and methods of
communicating via mobile communications networks.
Description of Related Art
[0003] The "background" description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description
which may not otherwise qualify as prior art at the time of filing,
are neither expressly or impliedly admitted as prior art against
the present invention.
[0004] It is well known in the field of wireless telecommunications
for regions of the radio spectrum to be assigned to different
mobile network operators (MNO) for their exclusive use through a
license. A license typically grants an MNO exclusive use over a
number of years of a predefined portion of the radio frequency
spectrum in which to deploy a mobile communications network (e.g.
GSM, WCDMA/HSPA, LTE/LTE-A). As a result of this approach, an
operator has guarantees of no other radio services interfering with
the radio resources that have been assigned to the operator, and
within the limitations of the license conditions it has exclusive
control over what radio technology it deploys in the network.
Consequently, a wireless telecommunications system that is
primarily designed to operate using radio resources that have been
licensed for exclusive use by the wireless telecommunications
system can operate with a degree of centralised control and
coordination to help make most efficient use of the available radio
resources. Such a wireless telecommunication system also manages
all the interference internally, based on standard specifications,
since the license grants it good immunity from external
interference sources. Coexistence of different devices deployed on
an MNO's licensed band is managed through conformance to relevant
radio standards. Licensed spectrum is today usually assigned to
operators via government-organised auctions, but so-called "beauty
contests" continue also to be in use.
[0005] It is also well known in the field of wireless
telecommunications for regions of the available radio spectrum to
remain unlicensed. Unlicensed (license exempt) radio spectrum may,
at least to some extent, be freely used by a number of different
technologies, such as Wi-Fi and Bluetooth and other non-3GPP radio
access technologies. Operating parameters for devices using
unlicensed spectrum bands are typically stipulated by technical
regulatory requirements such as e.g. the FCC Part 15 rule for 2.4
GHz ISM band. Coexistence of different devices deployed on
unlicensed band, due to the lack of centralised coordination and
control, is usually based on such technical rules and various
politeness protocols.
[0006] The use of wireless telecommunications system technologies
designed for operation on licensed radio spectrum, such as LTE, is
becoming more and more prevalent, both in terms of increasing
take-up of established uses for wireless telecommunications
technologies, and also the introduction of new uses, e.g., in the
developing field of machine-type communications (MTC). In order to
help provide more bandwidth to support this increased use of
wireless telecommunications technologies, it has recently been
proposed to use unlicensed radio spectrum resources to support
operations on licensed radio spectrum.
[0007] However, in contrast to licensed spectrum, unlicensed
spectrum can be shared and used among different technologies, or
different networks using the same technology, without any
co-ordinated/centralised control, for example to provide protection
against interference. As a consequence of this, the use of wireless
technologies in unlicensed spectrum can be subject to unpredictable
interference and has no guarantees of spectrum resources, i.e. the
radio connection takes place on a best effort basis. This means
that wireless network technologies, such as LTE, which are
generally designed to operate using licensed radio resources,
require modified approaches to allow them to efficiently use
unlicensed radio resources, and in particular to co-exist reliably
and fairly with other radio access technologies that may be
simultaneously operating in the unlicensed spectrum band.
[0008] Therefore, deploying a mobile radio access technology system
primarily designed to operate in licensed spectrum bands (i.e.
having exclusive access to, and hence a level of control over, the
relevant radio resources) in a manner which is required by
operation in unlicensed spectrum bands (i.e. without having
exclusive access to at least some of the relevant radio resources),
gives rise to new technical challenges.
SUMMARY
[0009] According to an aspect of the disclosure there is provided a
method of operating a terminal device in a wireless
telecommunications system for communicating with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the method comprises the steps: (a)
receiving an indication of a configuration setting for the
secondary component carrier from the network infrastructure
equipment; (b) establishing a validity period for the configuration
setting for the secondary component carrier; and (c) receiving data
from the network infrastructure equipment using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting.
[0010] According to another aspect of the disclosure there is
provided a terminal device for use in a wireless telecommunications
system for communicating with network infrastructure equipment
using a primary component carrier operating on radio resources
within a first frequency band and a secondary component carrier
operating on radio resources within a second frequency band,
wherein the terminal device comprises a controller unit and a
transceiver unit configured to operate together to: (a) receive an
indication of a configuration setting for the secondary component
carrier from the network infrastructure equipment; (b) establish a
validity period for the configuration setting for the secondary
component carrier; and (c) receive data from the network
infrastructure equipment using the primary component carrier and
the secondary component carrier operating in accordance with the
configuration setting for the secondary component carrier during
the validity period for the configuration setting.
[0011] According to another aspect of the disclosure there is
provided circuitry for a terminal device for use in a wireless
telecommunications system for communicating with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the circuitry comprises a controller
element and a transceiver element configured to operate together
to: (a) receive an indication of a configuration setting for the
secondary component carrier from the network infrastructure
equipment; (b) establish a validity period for the configuration
setting for the secondary component carrier; and (c) receive data
from the network infrastructure equipment using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting.
[0012] According to another aspect of the disclosure there is
provided a method of operating network infrastructure equipment in
a wireless telecommunications system for communicating with a
terminal device using a primary component carrier operating on
radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, wherein the method comprises the steps: (a)
establishing an indication of radio usage in the second frequency
band; (b) determining a configuration setting for the secondary
component carrier based on the indication of radio usage in the
second frequency band; (d) establishing a validity period for the
configuration setting for the secondary component carrier; (e)
transmitting an indication of the configuration setting for the
secondary component carrier to the terminal device; (f)
transmitting data to the terminal device using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting; and (g) determining if the validity period for the
configuration setting for the secondary component carrier has
expired, and if so, repeating steps (a) and (b).
[0013] According to another aspect of the disclosure there is
provided network infrastructure equipment for use in a wireless
telecommunications system for communicating with a terminal device
using a primary component carrier operating on radio resources
within a first frequency band and a secondary component carrier
operating on radio resources within a second frequency band,
wherein the network infrastructure equipment comprises a controller
unit and a transceiver unit configured to operate together to: (a)
establish an indication of radio usage in the second frequency
band; (b) determine a configuration setting for the secondary
component carrier based on the indication of measurements of radio
usage in the second frequency band; (d) establish a validity period
for the configuration setting for the secondary component carrier;
(e) transmit an indication of the configuration setting for the
secondary component carrier to the terminal device; (f) transmit
data to the terminal device using the primary component carrier and
the secondary component carrier operating in accordance with the
configuration setting for the secondary component carrier during
the validity period for the configuration setting; and (g)
determine if the validity period for the configuration setting for
the secondary component carrier has expired, and if so, to again
receive from the terminal device an indication of measurements of
radio usage in the second frequency band made by the terminal
device and determine a configuration setting for the secondary
component carrier based on the received measurements of radio usage
in the second frequency band.
[0014] According to another aspect of the disclosure there is
provided circuitry for network infrastructure equipment for use in
a wireless telecommunications system for communicating with a
terminal device using a primary component carrier operating on
radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, wherein the circuitry comprises a controller
element and a transceiver element configured to operate together
to: (a) establish an indication of measurements of radio usage in
the second frequency band; (b) determine a configuration setting
for the secondary component carrier based on the indication of
measurements of radio usage in the second frequency band; (d)
establish a validity period for the configuration setting for the
secondary component carrier; (e) transmit an indication of the
configuration setting for the secondary component carrier to the
terminal device; (f) transmit data to the terminal device using the
primary component carrier and the secondary component carrier
operating in accordance with the configuration setting for the
secondary component carrier during the validity period for the
configuration setting; and (g) determine if the validity period for
the configuration setting for the secondary component carrier has
expired, and if so, to again receive from the terminal device an
indication of measurements of radio usage in the second frequency
band made by the terminal device and determine a configuration
setting for the secondary component carrier based on the received
measurements of radio usage in the second frequency band.
[0015] Further respective aspects and features are defined by the
appended claims.
[0016] The foregoing paragraphs have been provided by way of
general introduction, and are not intended to limit the scope of
the following claims. The described embodiments, together with
further advantages, will be best understood by reference to the
following detailed description taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] A more complete appreciation of the disclosure and many of
the attendant advantages thereof will be readily obtained as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings wherein like reference numerals designate
identical or corresponding parts throughout the several views, and
wherein:
[0018] FIG. 1 provides a schematic diagram illustrating an example
of a mobile telecommunication system;
[0019] FIG. 2 provides a schematic diagram illustrating a LTE radio
frame;
[0020] FIG. 3 provides a schematic diagram illustrating an example
of a LTE downlink radio subframe;
[0021] FIG. 4 schematically represents a wireless
telecommunications system according to an embodiment of the
disclosure; and
[0022] FIG. 5 is a signalling ladder diagrams representing
communications between a base station and a terminal device
operating in accordance with some embodiments of the
disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] FIG. 1 provides a schematic diagram illustrating some basic
functionality of a mobile telecommunications network/system 100
operating in accordance with LTE principles and which may be
adapted to implement embodiments of the disclosure as described
further below. Various elements of FIG. 1 and their respective
modes of operation are well-known and defined in the relevant
standards administered by the 3GPP.RTM. body, and also described in
many books on the subject, for example, Holma H. and Toskala A [1].
It will be appreciated that operational aspects of the
telecommunications network which are not specifically described
below may be implemented in accordance with any known techniques,
for example according to the relevant standards.
[0024] The network 100 includes a plurality of base stations 101
connected to a core network 102. Each base station provides a
coverage area 103 (i.e. a cell) within which data can be
communicated to and from terminal devices 104. Data is transmitted
from base stations 101 to terminal devices 104 within their
respective coverage areas 103 via a radio downlink. Data is
transmitted from terminal devices 104 to the base stations 101 via
a radio uplink. The uplink and downlink communications are made
using radio resources that are licensed for use by the operator of
the network 100. The core network 102 routes data to and from the
terminal devices 104 via the respective base stations 101 and
provides functions such as authentication, mobility management,
charging and so on. Terminal devices may also be referred to as
mobile stations, user equipment (UE), user terminal, mobile radio,
and so forth. Base stations may also be referred to as transceiver
stations/nodeBs/e-nodeBs, and so forth.
[0025] Mobile telecommunications systems such as those arranged in
accordance with the 3GPP defined Long Term Evolution (LTE)
architecture use an orthogonal frequency division modulation (OFDM)
based interface for the radio downlink (so-called OFDMA) and a
single carrier frequency division multiple access scheme (SC-FDMA)
on the radio uplink. FIG. 2 shows a schematic diagram illustrating
an OFDM based LTE downlink radio frame 201. The LTE downlink radio
frame is transmitted from a LTE base station (known as an enhanced
Node B) and lasts 10 ms. The downlink radio frame comprises ten
subframes, each subframe lasting 1 ms. A primary synchronisation
signal (PSS) and a secondary synchronisation signal (SSS) are
transmitted in the first and sixth subframes of the LTE frame. A
physical broadcast channel (PBCH) is transmitted in the first
subframe of the LTE frame.
[0026] FIG. 3 is a schematic diagram of a grid which illustrates
the structure of an example conventional downlink LTE subframe. The
subframe comprises a predetermined number of symbols which are
transmitted over a 1 ms period. Each symbol comprises a
predetermined number of orthogonal subcarriers distributed across
the bandwidth of the downlink radio carrier.
[0027] The example subframe shown in FIG. 3 comprises 14 symbols
and 1200 subcarriers spread across a 20 MHz bandwidth licensed for
use by the operator of the network 100, and this example is the
first subframe in a frame (hence it contains PBCH). The smallest
allocation of physical resource for transmission in LTE is a
resource block comprising twelve subcarriers transmitted over one
subframe. For clarity, in FIG. 3, each individual resource element
is not shown, instead each individual box in the subframe grid
corresponds to twelve subcarriers transmitted on one symbol.
[0028] FIG. 3 shows in hatching resource allocations for four LTE
terminals 340, 341, 342, 343. For example, the resource allocation
342 for a first LTE terminal (UE 1) extends over five blocks of
twelve subcarriers (i.e. 60 subcarriers), the resource allocation
343 for a second LTE terminal (UE2) extends over six blocks of
twelve subcarriers (i.e. 72 subcarriers), and so on.
[0029] Control channel data can be transmitted in a control region
300 (indicated by dotted-shading in FIG. 3) of the subframe
comprising the first "n" symbols of the subframe where "n" can vary
between one and three symbols for channel bandwidths of 3 MHz or
greater and where "n" can vary between two and four symbols for a
channel bandwidth of 1.4 MHz. For the sake of providing a concrete
example, the following description relates to host carriers with a
channel bandwidth of 3 MHz or greater so the maximum value of "n"
will be 3 (as in the example of FIG. 3). The data transmitted in
the control region 300 includes data transmitted on the physical
downlink control channel (PDCCH), the physical control format
indicator channel (PCFICH) and the physical HARQ indicator channel
(PHICH). These channels transmit physical layer control
information. Control channel data can also or alternatively be
transmitted in a second region of the subframe comprising a number
of subcarriers for a time substantially equivalent to the duration
of the subframe, or substantially equivalent to the duration of the
subframe remaining after the "n" symbols. The data transmitted in
this second region is transmitted on the enhanced physical downlink
control channel (EPDCCH). This channel transmits physical layer
control information which may be in addition to that transmitted on
other physical layer control channels.
[0030] PDCCH and EPDCCH contain control data indicating which
subcarriers of the subframe have been allocated to specific
terminals (or all terminals or subset of terminals). This may be
referred to as physical-layer control signalling/data. Thus, the
PDCCH and/or EPDCCH data transmitted in the control region 300 of
the subframe shown in FIG. 3 would indicate that UE1 has been
allocated the block of resources identified by reference numeral
342, that UE2 has been allocated the block of resources identified
by reference numeral 343, and so on.
[0031] PCFICH contains control data indicating the size of the
control region (i.e. between one and three symbols for channel
bandwidths of 3 MHz or greater and between two and four symbols for
channel bandwidths of 1.4 MHz).
[0032] PHICH contains HARQ (Hybrid Automatic Request) data
indicating whether or not previously transmitted uplink data has
been successfully received by the network.
[0033] Symbols in a central band 310 of the time-frequency resource
grid are used for the transmission of information including the
primary synchronisation signal (PSS), the secondary synchronisation
signal (SSS) and the physical broadcast channel (PBCH). This
central band 310 is typically 72 subcarriers wide (corresponding to
a transmission bandwidth of 1.08 MHz). The PSS and SSS are
synchronisation signals that once detected allow a LTE terminal
device to achieve frame synchronisation and determine the physical
layer cell identity of the enhanced Node B transmitting the
downlink signal. The PBCH carries information about the cell,
comprising a master information block (MIB) that includes
parameters that LTE terminals use to properly access the cell. Data
transmitted to terminals on the physical downlink shared channel
(PDSCH), which may also be referred to as a downlink data channel,
can be transmitted in other resource elements of the subframe. In
general PDSCH conveys a combination of user-plane data and
non-physical layer control-plane data (such as Radio Resource
Control (RRC) and Non Access Stratum (NAS) signalling). The
user-plane data and non-physical layer control-plane data conveyed
on PDSCH may be referred to as higher layer data (i.e. data
associated with a layer higher than the physical layer).
[0034] FIG. 3 also shows a region of PDSCH containing system
information and extending over a bandwidth of R344. A conventional
LTE subframe will also include reference signals which are not
shown in FIG. 3 in the interests of clarity.
[0035] The number of subcarriers in a LTE channel can vary
depending on the configuration of the transmission network.
Typically this variation is from 72 sub carriers contained within a
1.4 MHz channel bandwidth to 1200 subcarriers contained within a 20
MHz channel bandwidth (as schematically shown in FIG. 3). As is
known in the art, data transmitted on the PDCCH, PCFICH and PHICH
is typically distributed on the subcarriers across the entire
bandwidth of the subframe to provide for frequency diversity.
[0036] The communications between the base stations 101 and the
terminal devices 104 are conventionally made using radio resources
that have been licensed for exclusive use by the operator of the
network 100. These licensed radio resources will be only a portion
of the overall radio spectrum. Other devices within the environment
of the network 100 may be wirelessly communicating using other
radio resources. For example, a different operators network may be
operating within the same geographical region using different radio
resources that have been licensed for use by the different
operator. Other devices may be operating using other radio
resources in an unlicensed radio spectrum band, for example using
Wi-Fi or Bluetooth technologies.
[0037] As noted above, it has been proposed that a wireless
telecommunications network using radio resources in a licensed
portion of the radio spectrum might be supported by using radio
resources in an unlicensed portion of the radio spectrum (i.e. a
portion of the radio spectrum over which the wireless
telecommunications network does not have exclusive access, but
rather which is shared by other access technologies and/or other
wireless telecommunications networks). In particular, it has been
proposed that carrier aggregation based techniques may be used to
allow unlicensed radio resources to be used in conjunction with
licensed radio resources.
[0038] In essence, carrier aggregation allows for communications
between a base station and a terminal device to be made using more
than one carrier. This can increase the maximum data rate that may
be achieved between a base station and a terminal device as
compared to when using only one carrier and can help enable more
efficient and productive use of fragmented spectrum. Individual
carriers that are aggregated are commonly referred to as component
carriers (or sometimes simply components). In the context of LTE,
carrier aggregation was introduced in Release 10 of the standard.
In accordance with the current standards for carrier aggregation in
an LTE-based system, up to five component carriers can be
aggregated for each of downlink and uplink. The component carriers
are not required to be contiguous with one another and can have a
system bandwidth corresponding to any of the LTE-defined values
(1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz), thereby
allowing a total bandwidth of up to 100 MHz. Of course it will be
appreciated this is just one example of a specific carrier
aggregation implementation and other implementations may allow for
different numbers of component carriers and/or bandwidths.
[0039] Further information on the operation of carrier aggregation
in the context of LTE-based wireless telecommunications systems can
be found in the relevant standards documents, such as ETSI TS 136
211 V11.5.0 (2014-01)/3GPP TS 36.211 version 11.5.0 Release 11 [2],
ETSI TS 136 212 V11.4.0 (2014-01)/3GPP TS 36.212 version 11.4.0
Release 11 [3]; ETSI TS 136 213 V11.6.0 (2014-03)/3GPP TS 36.213
version 11.6.0 Release 11 [4]; ETSI TS 136 321 V11.5.0
(2014-03)/3GPP TS 36.321 version 11.5.0 Release 11 [5]; and ETSI TS
136 331 V11.7.0 (2014-03)/3GPP TS 36.331 version 11.7.0 Release 11
[6].
[0040] In accordance with the terminology and implementation used
for carrier aggregation in the context of an LTE-based system, a
cell is denoted the `primary cell`, or Pcell, for a terminal device
if it is the cell that is initially configured during connection
setup for the terminal device. Thus the primary cell handles RRC
(radio resource control) connection establishment/re-establishment
for the terminal device. The primary cell is associated with a
downlink component carrier and an uplink component carrier (CoC).
These may sometimes be referred to herein as primary component
carriers. A cell that is configured for use by the terminal device
after initial connection establishment on the Pcell is termed a
`secondary cell`, or Scell. Thus the secondary cells are configured
after connections establishment to provide additional radio
resources. The carriers associated with Scells may sometimes be
referred to herein as secondary component carriers. Since in LTE up
to five component carriers can be aggregated, up to four Scells
(correspondingly associated with up to four secondary component
carriers) can be configured for aggregation with the primary cell
(associated with the primary component carrier). An Scell might not
have both a downlink and uplink component carrier and the
association between uplink component carriers and downlink
component carriers is signalled in SIB2 on each downlink component
carrier. The primary cell supports PDCCH and PDSCH on downlink and
PUSCH and PUCCH on uplink whereas the secondary cell(s) support
PDCCH and PDSCH on downlink and PUSCH on uplink, but not PUCCH.
Measurement and mobility procedures are handled on the Pcell and
the Pcell cannot be de-activated. The Scell(s) may be dynamically
activated and deactivated, for example according to traffic needs,
though MAC layer signalling to the terminal device. An Scells for a
terminal device may also be deactivated automatically (time out) if
the terminal device does not receive any transmission resource
allocations on the Scell for a threshold amount of time.
[0041] Some aspects of physical layer control signalling for an
LTE-based implementation of carrier aggregation based on the
current standards are now described.
[0042] Each downlink component carrier has the normal LTE control
channels: (E)PDCCH, PCFICH and PHICH. However, carrier aggregation
introduces the possibility of so-called cross-carrier scheduling
(XCS) on PDCCH. To support cross-carrier scheduling, a downlink
control information (DCI) message on PDCCH includes a carrier
indicator field (CIF) comprising three bits to indicate which of
the component carriers the PDCCH message applies to. If there is no
CIF, the PDCCH is treated as applying to the carrier on which it is
received. A motivation for providing cross-carrier scheduling
primarily applies for heterogeneous network (het-net) scenarios
where overlaid macro- and small-cells may operate carrier
aggregation in the same band. The effects of interference between
the respective macro- and small-cells' PDCCH signalling can be
mitigated by having the macro-cell transmit its PDCCH signalling on
one component carrier at relatively high transmit power (to provide
coverage across the macro-cell), while the small-cells use an
alternative component carrier for their PDCCH scheduling.
[0043] The control region supporting PDCCH may differ in size (i.e.
number of OFDM symbols) between component carriers, so they can
carry different PCFICH values. However, the potential for
interference in the control region in a het-net implementation may
mean that PCFICH cannot be decoded on a particular component
carrier. Therefore, current LTE standards allow for each component
to carrier a semi-static indication of which OFDM symbol PDSCH can
be assumed to begin in each subframe. If fewer OFDM symbols are
actually used for the control region, the free/spare OFDM symbol(s)
may be used for PDSCH transmissions to terminal devices which are
not being cross-carrier scheduled as they will decode the actual
PCFICH. If more OFDM symbols actually used for the control region,
there will be some degree of performance degradation for the
cross-carrier scheduled terminal devices.
[0044] PHICH signalling is sent on the downlink component carrier
that sent the PDCCH signalling containing the PUSCH allocation to
which the PHICH signalling relates. Accordingly, one downlink
component carrier may carry PHICH for more than one component
carrier.
[0045] In the uplink, the basic operation of PUCCH is not altered
by the introduction of carrier aggregation. However, a new PUCCH
format (format 3) is introduced to support the sending of
acknowledgement signalling (ACK/NACK signalling) for multiple
downlink component carriers, and with some alterations to format 1b
to increase the number of ACK/NACK bits it can carry.
[0046] In current LTE-based carrier aggregation scenarios, primary
and secondary synchronisation signalling (PSS and SSS) are
transmitted on all component carriers using the same physical-layer
cell identity (PCI) and component carriers are all synchronised
with one another. This can help with cell search and discovery
procedures. Issues relating to security and system information (SI)
are handled by the Pcell. In particular, when activating an Scell,
the Pcell delivers the relevant SI for the Scell to the terminal
device using dedicated RRC signalling. If the system information
relating to a Scell changes, the Scell is released and re-added by
Pcell RRC signalling (in one RRC message). Pcell changes, e.g. due
to long-term fluctuations in channel quality across the Pcell
bandwidth, are handled using a modified handover procedure. The
source Pcell passes all the relevant carrier aggregation (CA)
information to the target Pcell so the terminal device can begin to
use all the assigned component carriers when handover is
complete.
[0047] Random access procedures are primarily handled on the uplink
component carrier of Pcell for a terminal device, although some
aspects of contention resolution signalling may be cross-carrier
scheduled to another serving cell (i.e. an Scell).
[0048] As noted above, carrier aggregation is one approach for
making use of unlicensed radio spectrum resources in wireless
communication networks which are primarily designed to use licensed
radio spectrum. In broad summary, a carrier aggregation based
approach may be used to configure and operate a first component
carrier (e.g. a primary component carrier associated with a Pcell
in LTE terminology) within a region of the radio spectrum that has
been licensed for use by a wireless telecommunications network, and
to also configure and operate one or more further component
carriers (e.g. a secondary component carrier associated with an
Scell in LTE terminology) in an unlicensed region of the radio
spectrum. The secondary component carrier(s) operating in the
unlicensed region of the radio spectrum may do so in an
opportunistic manner by making use of the unlicensed radio
resources when they are available. There may also be provisions
made for restricting the extent to which a given operator can make
use of the unlicensed radio resources, for example by defining what
might be referred to as politeness protocols.
[0049] Although known carrier aggregation schemes can form a basis
for using unlicensed radio spectrum resources (or other forms of
shared radio resources) in conjunction with licensed radio spectrum
resources, some modifications to known carrier aggregation
techniques may be appropriate to help optimise performance. This is
because radio interference in the unlicensed radio spectrum can be
expected to be subject to a wider range of unknown and
unpredictable variations in time and frequency than might be seen
within a region of the radio spectrum which has been licensed for
use by a particular wireless applications system. For a given
wireless telecommunications system operating in accordance with a
given technology, such as LTE-A, interference in the unlicensed
radio spectrum may arise from other systems operating quantity same
technology, or systems operating according to different
technologies, such as Wi-Fi or Bluetooth.
[0050] FIG. 4 schematically shows a telecommunications system 400
according to an embodiment of the disclosure. The
telecommunications system 400 in this example is based broadly on a
LTE-type architecture. As such many aspects of the operation of the
telecommunications system 400 are standard and well understood and
not described here in detail in the interest of brevity.
Operational aspects of the telecommunications system 400 which are
not specifically described herein may be implemented in accordance
with any known techniques, for example according to the established
LTE-standards and known variations thereof.
[0051] The telecommunications system 400 comprises a core network
part (evolved packet core) 402 coupled to a radio network part. The
radio network part comprises a base station (evolved-nodeB) 404, a
first terminal device 406 and a second terminal device 408. It will
of course be appreciated that in practice the radio network part
may comprise a plurality of base stations serving a larger number
of terminal devices across various communication cells. However,
only a single base station and two terminal devices are shown in
FIG. 4 in the interests of simplicity.
[0052] Although not part of the telecommunications system 400
itself, also shown in FIG. 4 are some other devices which are
operable to wirelessly communicate with one another and which are
operating within the radio environment of the telecommunications
system 400. In particular, there is a pair of wireless access
devices 416 communicating with one another via radio link 418
operating in accordance with a Wi-Fi standard and a pair of
Bluetooth devices 420 communicating with one another via radio link
422 operating in accordance with a Bluetooth standard. These other
devices represent a potential source of radio interference for the
telecommunications system 400. It will be appreciated that in
practice there will typically be many more such devices operating
in the radio environment of the wireless telecommunications system
400, and only two pairs of devices 416, 418 are shown in FIG. 4 for
simplicity.
[0053] As with a conventional mobile radio network, the terminal
devices 406, 408 are arranged to wirelessly communicate data to and
from the base station (transceiver station) 404. The base station
is in turn communicatively connected to a serving gateway, S-GW,
(not shown) in the core network part which is arranged to perform
routing and management of mobile communications services to the
terminal devices in the telecommunications system 400 via the base
station 404. In order to maintain mobility management and
connectivity, the core network part 402 also includes a mobility
management entity (not shown) which manages the enhanced packet
service, EPS, connections with the terminal devices 406, 408
operating in the communications system based on subscriber
information stored in a home subscriber server, HSS. Other network
components in the core network (also not shown for simplicity)
include a policy charging and resource function, PCRF, and a packet
data network gateway, PDN-GW, which provides a connection from the
core network part 402 to an external packet data network, for
example the Internet. As noted above, the operation of the various
elements of the communications system 400 shown in FIG. 4 may be
broadly conventional apart from where modified to provide
functionality in accordance with embodiments of the disclosure as
discussed herein.
[0054] The terminal devices 406, 408 each comprise a transceiver
unit 406a, 408a for transmission and reception of wireless signals
and a controller unit 406b, 408b configured to control the
operation of the respective devices 406, 408 in accordance with
embodiments of the disclosure. The respective controller units
406b, 408b may each comprise a processor unit which is suitably
configured/programmed to provide the desired functionality
described herein using conventional programming/configuration
techniques for equipment in wireless telecommunications systems.
For each of the terminal devices 406, 408, their respective
transceiver units 406a, 408a and controller units 406b, 408b are
schematically shown in FIG. 4 as separate elements for ease of
representation. However, it will be appreciated that for each
terminal device the functionality of these units can be provided in
various different ways, for example using a single suitably
programmed general purpose computer, or suitably configured
application-specific integrated circuit(s)/circuitry, or using a
plurality of discrete circuitry/processing elements for providing
different elements of the desired functionality. It will be
appreciated the terminal devices 406, 408 will in general comprise
various other elements associated with their operating
functionality in accordance with established wireless
telecommunications techniques (e.g. a power source, possibly a user
interface, and so forth).
[0055] As has become commonplace in the field of wireless
telecommunications, terminal devices may support Wi-Fi and
Bluetooth functionality in addition to cellular/mobile
telecommunications functionality. Thus the transceiver units 406a,
408a of the respective terminal devices may comprise functional
modules operable according to different wireless communications
operating standards. For example, the terminal devices' transceiver
units may each comprise an LTE transceiver module for supporting
wireless communications in accordance with an LTE-based operating
standard, a WLAN transceiver module for supporting wireless
communications in accordance with a WLAN operating standard (e.g. a
Wi-Fi standard), and a Bluetooth transceiver module for supporting
wireless communications in accordance with a Bluetooth operating
standard. The underlying functionality of the different transceiver
modules may be provided in accordance with conventional techniques.
For example, a terminal device may have separate hardware elements
to provide the functionality of each transceiver module, or
alternatively, a terminal device might comprise at least some
hardware elements which are configurable to provide some or all
functionality of multiple transceiver modules. Thus the transceiver
units 406a, 408a of the terminal devices 406, 408 represented in
FIG. 4 are assumed here to provide the functionality of an LTE
transceiver module, a Wi-Fi transceiver module and a Bluetooth
transceiver module in accordance with conventional wireless
communications techniques.
[0056] The base station 404 comprises a transceiver unit 404a for
transmission and reception of wireless signals and a controller
unit 404b configured to control the base station 404. The
controller unit 404b may comprise a processor unit which is
suitably configured/programmed to provide the desired functionality
described herein using conventional programming/configuration
techniques for equipment in wireless telecommunications systems.
The transceiver unit 404a and the controller unit 404b are
schematically shown in FIG. 4 as separate elements for ease of
representation. However, it will be appreciated that the
functionality of these units can be provided in various different
ways, for example using a single suitably programmed general
purpose computer, or suitably configured application-specific
integrated circuit(s)/circuitry or using a plurality of discrete
circuitry/processing elements for providing different elements of
the desired functionality. It will be appreciated the base station
404 will in general comprise various other elements associated with
its operating functionality. For example, the base station 404 will
in general comprise a scheduling entity responsible for scheduling
communications. The functionality of the scheduling entity may, for
example, be subsumed by the controller unit 404b.
[0057] Thus, the base station 404 is configured to communicate data
with the first and second terminal devices 406, 408 over respective
first and second radio communication links 410, 412. The wireless
telecommunications system 400 supports a carrier aggregation mode
of operation in which the first and second radio communication
links 410, 412 each comprise a wireless access interface provided
by multiple component carriers. For example, each radio
communication link may comprise a primary component carrier and one
or more secondary component carriers. Furthermore, the elements
comprising the wireless telecommunications system 400 in accordance
with this embodiment of the disclosure are assumed to support
carrier aggregation in an unlicensed spectrum mode. In this
unlicensed spectrum mode the base station communicates with
terminal devices using a primary component carrier operating on
radio resources within a first frequency band that has been
licensed for use by the wireless telecommunications system and one
or more secondary component carriers operating on radio resources
within a second frequency band that has not been licensed for
exclusive use by the wireless telecommunications system. The first
frequency band may sometimes be referred to herein as a licensed
frequency band and the second frequency band may sometimes be
referred to herein as an unlicensed (U) frequency band. In the
context of an LTE-based wireless telecommunications system, such as
that represented in FIG. 4, operation in the unlicensed frequency
band may be referred to as an LTE-U mode of operation. The first
(licensed) frequency band may be referred to as an LTE band (or
more particularly an LTE-A band) and the second (unlicensed)
frequency band may be referred to as an LTE-U band. Resources on
the LTE-U band may be referred to as U-resources. A terminal device
able to make use of U-resources may be referred to as a U-terminal
device (or U-UE). More generally, the qualifier "U" may be used
herein to conveniently identify operations in respect of the
unlicensed frequency band.
[0058] It will be appreciated that the use of carrier aggregation
techniques and the use of unlicensed spectrum resources (i.e.
resources that may be used by other devices without centralised
coordination) in accordance with embodiments of the disclosure may
be based generally on previously proposed principles for such modes
of operation, for example as discussed above, but with
modifications as described herein to provide additional
functionality in accordance with embodiments of the present
disclosure. Accordingly, aspects of the carrier aggregation and
unlicensed spectrum operation which are not described in detail
herein may be implemented in accordance with known techniques.
[0059] Modes of operation for the wireless telecommunications
network 400 represented in FIG. 4 in accordance with certain
embodiments of the disclosure will now be described. The general
scenario for these embodiments is assumed to be one in which a
carrier aggregation capable terminal device is operating in an
LTE-A cell as normal, and the base station determines that it
should configure the LTE-U capable terminal device with an
additional aggregated carrier using LTE-U resources. The specific
reason why the base station determines that it should configure a
particular terminal device for LTE-U based carrier aggregation is
not significant. Thus the LTE-A carrier provides a Pcell for the
terminal device and the LTE-U resources provide one or more
Scell(s) for the terminal device. It will be appreciated the LTE-A
resources may also be used to provide component carriers associated
with one or more further Scells(s) in accordance with conventional
carrier aggregation techniques. For the examples described with
reference to FIG. 4, the LTE-A transmissions in the licensed
frequency band and the LTE-U transmissions in the unlicensed
frequency band, and thus the Pcell and Scell(s), are both made from
the same base station 404, but this may not be the case in other
example embodiments. The LTE-U carrier could in general be utilised
with a TDD (time division duplex) or FDD (frequency division
duplex) frame structure. However, a consequence of some aspects of
existing regulatory restrictions on unlicensed spectrum usage in
some regions means that TDD or downlink-only FDD operation may, at
least currently, be more likely.
[0060] FIG. 5 is a signalling ladder diagram schematically
representing modes of operation for one of the terminal devices
(UEs) 406, 408 and the base station (eNB) 404 schematically
represented in FIG. 4. The operation is for communicating using a
primary component carrier (associated with a primary cell)
operating on radio resources within a first frequency band and a
secondary component carrier (associated with a secondary cell)
operating on radio resources within a second frequency band in
accordance with certain embodiments of the present disclosure. As
discussed above, the first frequency band is taken to correspond
with resources that have been licensed for dedicated use by the
operator of the wireless telecommunications system 400 whereas the
second frequency band is taken to correspond with resources that
are shared by other wireless communication technologies, and in
particular in this example by Wi-Fi. In broad summary, some
embodiments of the disclosure introduce the concept of a validity
period for a configuration setting for a secondary carrier in the
context of carrier aggregation using radio resources that are
shared between different network operators and/or wireless access
technologies.
[0061] The operation represented in FIG. 5 is generally iterative
and is shown starting from a stage at which the terminal device is
configured for operation on the primary cell associated with the
primary carrier, but is not yet configured for operation on the
secondary cell associated with the secondary carrier. This may be,
for example, because the terminal device has only just connected to
the primary cell or because a previous secondary cell configuration
is no longer valid.
[0062] In step S1 the terminal device makes measurements of radio
usage in the second frequency band in its environment. In
particular, the terminal device measures the degree of radio usage
at different frequencies across the second frequency band. For
example, the terminal device may use its WLAN transceiver module to
scan for activity associated with other wireless communication
devices, for example, Wi-Fi access points. From this the terminal
device may establish, for example, an indication of frequency
resources used by other wireless communications devices and/or an
indication of a received signal strength for wireless
communications associated with other wireless communications
devices and/or an indication of an identifier for the other
wireless communications device (e.g. SSID). The terminal device may
also scan for radio usage in the second frequency band by other
devices operating according to other operating standards, for
example Bluetooth and/or other LTE networks. In some embodiments
the terminal device might not separately measure radio usage by
different technologies, but may simply measure an aggregate level
of radio signals (which may include radio noise) in its environment
at different frequencies across the second frequency band.
[0063] In step S2 the terminal device transmits an indication of
the measurements of radio usage at different frequencies across the
second frequency band to the base station. This may be done on
uplink radio resources on the already-configured primary cell to
which the terminal device is connected in accordance with
conventional signalling techniques, for example in accordance with
the established principles of measurement report RRC
signalling.
[0064] In Step S3, the base station determines a configuration
setting for the secondary component carrier based on the received
measurements of radio usage in the second frequency band. For
example, the configuration setting may define transmission
resources (e.g. in terms of time and/or frequency resources)
selected from within the second frequency band to use for the
secondary component carrier.
[0065] The base station may determine appropriate transmission
resources for the secondary cell configuration from the received
measurements of radio usage in accordance with any established
techniques for selecting appropriate transmission resources to use
in a competitive (opportunistic) radio environment based on
measurements of existing usage. For example, the base station may
avoid transmission resources in regions of the second frequency
band for which the terminal device measurement reports indicate a
relatively high degree of radio usage, and may instead
preferentially select a configuration for the secondary carrier
that makes use of transmission resources in spectral regions having
a relatively low degree of radio usage.
[0066] In step S4 the base station transmits an indication of the
chosen configuration setting for the secondary carrier to the
terminal device. This may be done on downlink radio resources on
the already-configured primary cell in accordance with conventional
signalling techniques, for example in accordance with the
established principles of radio bearer (re)configuration message
RRC signalling.
[0067] In step S5 the terminal device configures its transceiver
unit (and in particular the LTE transceiver module component of its
transceiver unit) in accordance with the configuration setting
information received from the base station, for example by
appropriate tuning of the transceiver circuitry. This may be formed
in accordance with conventional techniques for radio bearer
configuration setting.
[0068] In step S6 the terminal device establishes a validity period
for the configuration setting for the secondary carrier received in
step S4 and starts a corresponding validity timer. The validity
period is a time duration for which the configuration setting is to
be assumed to be valid, thereby providing for a
semi-static/semi-persistent secondary cell configuration. The
duration of the validity period for the configuration setting may
in some cases be fixed. For example, the duration of the validity
period may be defined in an operating standard for the wireless
telecommunications system, for example based on regulatory
agreements between different operators and/or access technologies
to ensure "fairness". In another example, the duration of the
validity period may be established from system information
transmitted by the base station or from other signalling previously
received from the base station, for example during initial
connection establishment for the terminal device. In yet other
examples, the duration of the validity period for a given
configuration setting may be selected by the base station and
communicated to the terminal device, for example in association
with the indication of the configuration setting transmitted from
the base station to the terminal device in step S4. This can allow
for more flexible operation. For example, if the measurement
reports received from the terminal device in step S2 indicate very
little radio usage in the second frequency band, the base station
may determine a relatively long validity period should be used,
whereas if the measurement reports received from the terminal
device in step S2 indicate relatively high radio usage in the
second frequency band, the base data may determine a relatively
short validity period should be used. That is to say, the validity
period may be determined by taking account of the degree of radio
traffic in the second frequency band. In some examples the duration
of the validity period may be greater than an amount selected from
the group comprising: 0.1 seconds; 1 second; 2 seconds; 3 second;
and 5 seconds and/or less than an amount selected from the group
comprising: 1 hour, 1 minute, 10 seconds; and 5 seconds. However,
the specific values for the validity period may be selected
according to the implementation at hand. In general, a longer
validity period will reduce the frequency with which the terminal
device should measure radio usage across the second frequency band
and will reduce the associated signalling overhead, whereas a
shorter validity period will reduce the extent to which
communications between the base station and the terminal device
interfere with other devices trying to access the shared resources
of the second frequency band.
[0069] In step S7 the base station starts communicating with the
terminal device using the primary carrier and the secondary carrier
configured in accordance with the current configuration setting for
the secondary component carrier. This may be done based on
established carrier aggregation techniques and using
previously-proposed techniques for making use of unlicensed
frequency spectrum. The communication of data between the base
station and the terminal device may continue as schematically
indicated by the arrow below the representation of step S7 in FIG.
5.
[0070] In step S8 the terminal device measures channel quality for
the secondary carrier. This is performed in parallel with the
ongoing communication of data from the base station to the terminal
device using the primary and secondary carriers. The measurement of
channel quality for the secondary carrier may be based on
established channel quality measurement techniques in wireless
telecommunications systems.
[0071] In particular, the measurements undertaken in step S8 may
correspond with those undertaken for conventional channel quality
indicator (CQI) reporting in LTE wireless communication systems.
That is to say, step S8 may correspond with the measurements that
are already normally undertaken for conventional CQI reporting on a
secondary cell is a carrier aggregation scenario (for example,
using sounding reference symbols). In this regard, and although not
shown in FIG. 5, the terminal device may report the channel quality
measurements back to the base station to assist the base station in
making scheduling decisions for allocating transmission resources
to the terminal device on the secondary carrier in accordance with
conventional LTE techniques.
[0072] The channel quality measurements of step S8 may continue in
parallel with the ongoing communication of data using the first and
secondary carriers that started in step S7. This may continue until
one or other of two conditions is satisfied, as schematically
indicated in step S9.
[0073] Thus, step S9 in FIG. 5 indicates that the base station and
terminal device continue to communicate data using the primary and
secondary carriers in accordance with conventional carrier
aggregation techniques as applied to unlicensed spectrum operation
until either (a) the validity period established in step S6 expires
or (b) the channel quality measurements for the secondary carrier
indicate the channel conditions associated with the secondary
carrier have fallen below a threshold quality level. The threshold
quality level may be determined according to the implementation at
hand. For example, the threshold may correspond with a level below
which the channel quality is considered to be too poor for
supporting data transfer with at least a minimum acceptable data
rate, or it may correspond with a level indicative of the presence
of signals from devices using another radio access technology on
the same frequency which would then simply identify potential
interference from or to the other radio access technology.
[0074] If either of the relevant events occur, the terminal device
assumes the configuration setting for the secondary carrier
received in step S4 is no longer valid, and the terminal device
returns to step S1 of the processing represented in FIG. 5. Thus,
the terminal device again measures radio usage across the
unlicensed band (second band) and proceeds to transmit an
indication of the measures radio usage to the base station.
Processing may then continue as described above. This results in
the base station determining an updated configuration setting for
the secondary carrier in a subsequent iteration of step S3, and
communicating the updated configuration setting to the terminal
device in a subsequent iteration of step S4, thereby allowing the
terminal device to configure its LTE transceiver and subsequently
receive data on the secondary carrier in accordance with the
updated configuration setting, and so on, with repeated iterations
through the steps of FIG. 5.
[0075] Thus the approach represented in FIG. 5 provides for a
semi-persistent/semi-static secondary cell configuration (e.g. in
terms of the transmission resources in the second frequency band
which are to be used for the secondary carrier) to be used when
aggregating unlicensed radio spectrum transmission resources with
licensed radio spectrum transmission resources. This approach has
been found by the inventors to provide a number of advantages. For
example, the approach can help to conserve terminal device battery
power since the terminal device can be configured to undertake the
measurements of radio usage across the secondary frequency band
which are used by the base station to determine a suitable
configuration setting (e.g. frequency setting) for the secondary
carrier only when the existing configuration becomes unusable
and/or after the validity period has expired. The use of a validity
period after which the radio usage across the second frequency band
is re-measured by the terminal device and reported to the base
station can help to prevent the wireless telecommunications system
from overly impacting the ability of other wireless communication
systems (e.g. Wi-Fi or Bluetooth or another LTE system) to use the
shared resources of the unlicensed radio spectrum comprising the
second frequency band.
[0076] It will be appreciated the approaches described above may be
modified in accordance with other embodiments of the invention. For
example, the order in which the steps of FIG. 5 are performed may
be different in other implementations. For example, steps S5 and S6
may be reversed, or in the event the validity period is fixed, step
S6 may be performed before step S1.
[0077] Furthermore, it will be appreciated that while in the above
described embodiments the base station establishes an indication of
radio usage across the U band based on measurements of channel
conditions made by the terminal device and reported to the base
station (in steps S1 and S2), in accordance with other embodiments
of the disclosure, the base station may establish a measure of
radio usage in the second frequency band in a different way. That
is to say, in some embodiments of the disclosure a terminal device
need not be involved in measuring and reporting channel conditions
used by the base station to select an appropriate carrier
configuration setting (i.e. in accordance with some embodiments
there may be no steps correspondence with steps S1 and S2 described
above). For example, the base station may itself measure radio
usage at different frequencies across the second frequency band
rather than, or in addition to, relying on feedback received from
one or more terminal devices.
[0078] Furthermore, while the above-described embodiments have
focused on an implementation in which a single secondary
carrier/Scell is associated with the second frequency band, the
same principles can be applied when using multiple secondary
carrier(s)/Scell(s) in the second frequency band. In this case each
of the multiple secondary carrier(s) may be associated with the
same or different validity period, and may be configured at the
same time or may be staggered.
[0079] Furthermore, it will be appreciated that in some example
embodiments, step S9 may be modified so that a currently-used
component carrier configuration becomes invalid only on expiry of
its validity period. That is to say, the carrier configuration may,
at least so far as the terminal device is concerned, remain valid
even if the channel quality becomes very poor. In this case the
base station may simply choose not to schedule further
transmissions for the terminal device until the base station
receives an updated indication of radio usage across the second
carrier in an iteration of step S2 following expiry of the terminal
device's validity period, thereby allowing the second carrier to be
re-configured. Furthermore, in yet another example, step S9 may be
modified so that a currently-used component carrier configuration
becomes invalid only if the measured channel quality falls below
the threshold level. That is to say, some implementations may not
adopt an approach using a validity period. That is to say, there
may be no step corresponding to S6.
[0080] Furthermore, in the examples described above it is assumed
the terminal device will consider the secondary carrier
configuration to become invalid if either of the conditions of step
S9 are met. However, in another example the terminal device may
return to step S1 as described above if either of the conditions of
step S9 are met, but may nonetheless continue to assume the current
configuration setting for the secondary carrier remains valid until
an indication of a new configuration setting is received from the
base station.
[0081] As described above, step S1 is performed in a repeated
manner in response to one of the conditions of step S9 being met.
However, in some examples step S1 may also be triggered by the base
station. For example, the base station may be configured to
transmit a message to the terminal device to request that the
terminal device provides the base station with an indication of
radio usage in the second frequency band (i.e. request that the
terminal device performs steps corresponding to steps S1 and S2 in
FIG. 5). This request may, for example, be made in accordance with
conventional control signalling techniques on the primary carrier.
This can allow the base station to initiate the process of
reconfiguring the secondary carrier before the validity period
expires or the channel conditions fall below an acceptable level.
Furthermore, this can be the process by which the base station
initiates step S1 in a first iteration of the process represented
in FIG. 5 (i.e. when it is determined that carrier aggregation
using resources in the second frequency band is to be commenced for
the terminal device).
[0082] It will be appreciated that while the above-described
embodiments are focused on a single base station supporting both
the primary component carrier the secondary component carrier, more
generally these could be transmitted from separate base stations.
In this regard, the network-side processing in accordance with
embodiments of the present disclosure may be performed by network
infrastructure equipment which comprises, for example, one base
station or more than one base station, and potentially other
network infrastructure equipment elements according to the
operating principles of the wireless telecommunications network in
which the approach is implemented.
[0083] It will be appreciated the principles described above may be
applied in respect of a wireless telecommunications system
supporting carrier aggregation with secondary component carriers
operating in a frequency band over which the wireless
telecommunications system does not have exclusive control
irrespective of whether or not the wireless telecommunications
system requires an administrative license to operate in the
secondary frequency band. That is to say, it will be appreciated
the terminology "unlicensed" is used herein for convenience to
refer to operation in a band over which the wireless
telecommunications system does not have exclusive access. In many
implementations this will correspond with a license exempt
frequency band. However, in other implementations the operation may
be applied in a frequency band which is not unlicensed in the
strict administrative sense, but which is nonetheless available for
shared/opportunistic use by devices operating according to
different wireless access technologies (e.g. LTE-based, Wi-Fi-based
and/or Bluetooth-based technologies) and/or multiple networks
operating according to the same technology (e.g. LTE-based wireless
communication systems provided by different network operators). In
this regard the terminology such as "unlicensed frequency band" may
be considered to refer generally to a frequency band in which
resources are shared by different wireless communications systems.
Accordingly, while the term "unlicensed" is commonly used to refer
to these types of frequency bands, in some deployment scenarios an
operator of a wireless telecommunications system may nonetheless be
required to hold an administrative license to operate in these
frequency bands.
[0084] Thus there has been described a method of operating a
terminal device and a base station in a wireless telecommunications
system to communicate with one another using a primary component
carrier operating on radio resources within a first frequency band
and a secondary component carrier operating on radio resources
within a second frequency band. The terminal device makes
measurements of radio usage in the second frequency band, e.g. by
other devices which are not part of the wireless telecommunications
system but which can also use radio resources within the second
frequency band. The terminal device transmits an indication of the
measurements to the base station, and on the basis if this the base
station establishes a configuration setting for the secondary
component carrier, for example in terms of frequency resources to
use for the secondary component carrier. The configuration setting
is associated with a validity period during which the base station
communicates data to the terminal device using the primary
component carrier and the secondary component carrier operating in
accordance with its configuration setting. When the validity period
expires, the terminal device again measures and reports on radio
usage so the base station can determine an updated configuration
setting for the secondary component carrier that takes account of
any changes in radio usage during the validity period.
[0085] Further particular and preferred aspects of the present
invention are set out in the accompanying independent and dependent
claims. It will be appreciated that features of the dependent
claims may be combined with features of the independent claims in
combinations other than those explicitly set out in the claims.
[0086] Thus, the foregoing discussion discloses and describes
merely exemplary embodiments of the present invention. As will be
understood by those skilled in the art, the present invention may
be embodied in other specific forms without departing from the
spirit or essential characteristics thereof. Accordingly, the
disclosure of the present invention is intended to be illustrative,
but not limiting of the scope of the invention, as well as other
claims. The disclosure, including any readily discernible variants
of the teachings herein, define, in part, the scope of the
foregoing claim terminology such that no inventive subject matter
is dedicated to the public.
[0087] Respective features of the present disclosure are defined by
the following numbered paragraphs:
[0088] Paragraph 1. A method of operating a terminal device in a
wireless telecommunications system for communicating with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the method comprises the steps: (a)
receiving an indication of a configuration setting for the
secondary component carrier from the network infrastructure
equipment; (b) establishing a validity period for the configuration
setting for the secondary component carrier; and (c) receiving data
from the network infrastructure equipment using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting.
[0089] Paragraph 2. The method of paragraph 1, further comprising
making measurements of radio usage in the second frequency band and
transmitting an indication of the measurements of radio usage in
the second frequency band to the network infrastructure equipment
prior to step (a).
[0090] Paragraph 3. The method of paragraph 2, further comprising
determining if the validity period for the configuration setting
for the secondary component carrier has expired, and if so, making
measurements of radio usage in the second frequency band and
transmitting an indication of the measurements of radio usage in
the second frequency band to the network infrastructure
equipment.
[0091] Paragraph 4. The method of any one of paragraphs 1 to 3,
further comprising determining if the validity period for the
configuration setting for the secondary component carrier has
expired, and if so, releasing the configuration setting.
[0092] Paragraph 5. The method of any one of paragraphs 1 to 4,
further comprising: receiving an indication of an updated
configuration setting for the secondary component carrier from the
network infrastructure equipment after the validity period for the
configuration setting for the secondary component carrier has
expired; establishing a validity period for the updated
configuration setting for the secondary component carrier; and
receiving data from the network infrastructure equipment using the
primary component carrier and the secondary component carrier
operating in accordance with the updated configuration setting for
the secondary component carrier during the validity period for the
updated configuration setting.
[0093] Paragraph 6. The method of any one of paragraphs 1 to 5,
further comprising performing channel quality measurements for the
secondary component carrier and determining if the channel quality
measurements indicate the channel quality is below a threshold
channel quality, and if so, making measurements of radio usage in
the second frequency band and transmitting an indication of the
measurements of radio usage in the second frequency band to the
network infrastructure equipment.
[0094] Paragraph 7. The method of paragraph 6, further comprising:
receiving an indication of an updated configuration setting for the
secondary component carrier from the network infrastructure
equipment after transmitting an indication of the measurements of
radio usage in the second frequency band to the network
infrastructure equipment; establishing a validity period for the
updated configuration setting for the secondary component carrier;
and receiving data from the network infrastructure equipment using
the primary component carrier and the secondary component carrier
operating in accordance with the updated configuration setting for
the secondary component carrier during the validity period for the
updated configuration setting.
[0095] Paragraph 8. The method of any one of paragraphs 1 to 7,
further comprising receiving a request from the network
infrastructure equipment to provide the network infrastructure
equipment with an indication of radio usage in the second frequency
band, and making measurements of radio usage in the second
frequency band and transmitting an indication of the measurements
of radio usage in the second frequency band to the network
infrastructure equipment in response thereto.
[0096] Paragraph 9. The method of paragraph 8, further comprising:
receiving an indication of an updated configuration setting for the
secondary component carrier from the network infrastructure
equipment after transmitting an indication of the measurements of
radio usage in the second frequency band to the network
infrastructure equipment in response to receiving the request from
the network infrastructure equipment; establishing a validity
period for the updated configuration setting for the secondary
component carrier; and receiving data from the network
infrastructure equipment using the primary component carrier and
the secondary component carrier operating in accordance with the
updated configuration setting for the secondary component carrier
during the validity period for the updated configuration
setting.
[0097] Paragraph 10. The method of paragraph 2, wherein the
indication of the measurements of radio usage in the second
frequency band are transmitted to the network infrastructure
equipment using transmission resources in the first frequency
band.
[0098] Paragraph 11. The method of paragraph 2, wherein the
indication of the measurements of radio usage in the second
frequency band are transmitted to the network infrastructure
equipment using radio resource control, RRC, signalling.
[0099] Paragraph 12. The method of any one of paragraphs 1 to 11,
wherein the indication of a configuration setting for the secondary
component carrier is received from the network infrastructure
equipment using transmission resources in the first frequency
band.
[0100] Paragraph 13. The method of any one of paragraphs 1 to 12,
wherein the indication of a configuration setting for the secondary
component carrier is received from the network infrastructure
equipment using radio resource control, RRC, signalling.
[0101] Paragraph 14. The method of any one of paragraphs 1 to 13,
wherein the second frequency band comprises radio resources which
are shared with wireless communication devices that are not part of
the wireless telecommunications system.
[0102] Paragraph 15. The method of paragraph 2, wherein
communications from the network infrastructure equipment are
received by the terminal device with a receiver operating in
accordance with a first wireless communications operating standard
and the measurements of radio usage in the second frequency band
are made with a receiver operating in accordance with a second
wireless communications operating standard that is different from
the first wireless communications operating standard.
[0103] Paragraph 16. The method of paragraph 15, wherein the first
wireless communications operating standard is a cellular
telecommunications operating standard and the second wireless
communications operating standard is a non-cellular
telecommunications operating standard.
[0104] Paragraph 17. The method of paragraph 15 or 16, wherein the
second wireless communications operating standard is a wireless
local area network, WLAN, operating standard.
[0105] Paragraph 18. The method of paragraph 2, wherein the
indication of the measurements of radio usage in the second
frequency band transmitted to the network infrastructure equipment
comprises information regarding the use of radio resources in the
second frequency band by another wireless communications
device.
[0106] Paragraph 19. The method of paragraph 18, wherein the
information comprises one or more of: an indication of frequency
resources used by the other wireless communications device; an
indication of a received signal strength for wireless
communications associated with the other wireless communications
device; and an indication of an identifier for the other wireless
communications device.
[0107] Paragraph 20. The method of any one of paragraphs 1 to 19,
wherein the validity period is established in accordance with an
operating standard for the wireless telecommunications system.
[0108] Paragraph 21. The method of any one of paragraphs 1 to 20,
wherein the validity period is established from information
received from the network infrastructure equipment in association
with the configuration setting for the secondary component carrier
received from the network infrastructure equipment.
[0109] Paragraph 22. The method of any one of paragraphs 1 to 21,
wherein the duration of the validity period is greater than an
amount selected from the group comprising: 0.1 seconds; 1 second; 2
seconds; 3 second; and 5 seconds.
[0110] Paragraph 23. The method of any one of paragraphs 1 to 22,
wherein the duration of the validity period is less than an amount
selected from the group comprising: 1 hour, 1 minute, 10 seconds;
and 5 seconds.
[0111] Paragraph 24. The method of any one of paragraphs 1 to 23,
wherein the configuration setting for the secondary component
carrier comprises an indication of transmission resources to be
used for the secondary component carrier.
[0112] Paragraph 25. A terminal device for use in a wireless
telecommunications system for communicating with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the terminal device comprises a
controller unit and a transceiver unit configured to operate
together to: (a) receive an indication of a configuration setting
for the secondary component carrier from the network infrastructure
equipment; (b) establish a validity period for the configuration
setting for the secondary component carrier; and (c) receive data
from the network infrastructure equipment using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting.
[0113] Paragraph 26. Circuitry for a terminal device for use in a
wireless telecommunications system for communicating with network
infrastructure equipment using a primary component carrier
operating on radio resources within a first frequency band and a
secondary component carrier operating on radio resources within a
second frequency band, wherein the circuitry comprises a controller
element and a transceiver element configured to operate together
to: (a) receive an indication of a configuration setting for the
secondary component carrier from the network infrastructure
equipment; (b) establish a validity period for the configuration
setting for the secondary component carrier; and (c) receive data
from the network infrastructure equipment using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting.
[0114] Paragraph 27. A method of operating network infrastructure
equipment in a wireless telecommunications system for communicating
with a terminal device using a primary component carrier operating
on radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, wherein the method comprises the steps: (a)
establishing an indication of radio usage in the second frequency
band; (b) determining a configuration setting for the secondary
component carrier based on the indication of radio usage in the
second frequency band; (d) establishing a validity period for the
configuration setting for the secondary component carrier; (e)
transmitting an indication of the configuration setting for the
secondary component carrier to the terminal device; (f)
transmitting data to the terminal device using the primary
component carrier and the secondary component carrier operating in
accordance with the configuration setting for the secondary
component carrier during the validity period for the configuration
setting; and (g) determining if the validity period for the
configuration setting for the secondary component carrier has
expired, and if so, repeating steps (a) and (b).
[0115] Paragraph 28. Network infrastructure equipment for use in a
wireless telecommunications system for communicating with a
terminal device using a primary component carrier operating on
radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, wherein the network infrastructure equipment
comprises a controller unit and a transceiver unit configured to
operate together to: (a) establish an indication of radio usage in
the second frequency band; (b) determine a configuration setting
for the secondary component carrier based on the indication of
measurements of radio usage in the second frequency band; (d)
establish a validity period for the configuration setting for the
secondary component carrier; (e) transmit an indication of the
configuration setting for the secondary component carrier to the
terminal device; (f) transmit data to the terminal device using the
primary component carrier and the secondary component carrier
operating in accordance with the configuration setting for the
secondary component carrier during the validity period for the
configuration setting; and (g) determine if the validity period for
the configuration setting for the secondary component carrier has
expired, and if so, to again receive from the terminal device an
indication of measurements of radio usage in the second frequency
band made by the terminal device and determine a configuration
setting for the secondary component carrier based on the received
measurements of radio usage in the second frequency band.
[0116] Paragraph 29. Circuitry for network infrastructure equipment
for use in a wireless telecommunications system for communicating
with a terminal device using a primary component carrier operating
on radio resources within a first frequency band and a secondary
component carrier operating on radio resources within a second
frequency band, wherein the circuitry comprises a controller
element and a transceiver element configured to operate together
to: (a) establish an indication of measurements of radio usage in
the second frequency band; (b) determine a configuration setting
for the secondary component carrier based on the indication of
measurements of radio usage in the second frequency band; (d)
establish a validity period for the configuration setting for the
secondary component carrier; (e) transmit an indication of the
configuration setting for the secondary component carrier to the
terminal device; (f) transmit data to the terminal device using the
primary component carrier and the secondary component carrier
operating in accordance with the configuration setting for the
secondary component carrier during the validity period for the
configuration setting; and (g) determine if the validity period for
the configuration setting for the secondary component carrier has
expired, and if so, to again receive from the terminal device an
indication of measurements of radio usage in the second frequency
band made by the terminal device and determine a configuration
setting for the secondary component carrier based on the received
measurements of radio usage in the second frequency band.
REFERENCES
[0117] [1] Holma H. and Toskala A, "LTE for UMTS OFDMA and SC-FDMA
based radio access", John Wiley and Sons, 2009 [0118] [2] ETSI TS
136 211 V11.5.0 (2014-01)/3GPP TS 36.211 version 11.5.0 Release 11
[0119] [3] ETSI TS 136 212 V11.4.0 (2014-01)/3GPP TS 36.212 version
11.4.0 Release 11 [0120] [4] ETSI TS 136 213 V11.6.0 (2014-03)/3GPP
TS 36.213 version 11.6.0 Release 11 [0121] [5] ETSI TS 136 321
V11.5.0 (2014-03)/3GPP TS 36.321 version 11.5.0 Release 11 [0122]
[6] ETSI TS 136 331 V11.7.0 (2014-03)/3GPP TS 36.331 version 11.7.0
Release 11
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