U.S. patent application number 17/730806 was filed with the patent office on 2022-08-11 for cif-value to component carrier mapping reconfiguration.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Robert Baldemair, Dirk Gerstenberger, Daniel Larsson, Stefan Parkvall.
Application Number | 20220256541 17/730806 |
Document ID | / |
Family ID | 1000006292421 |
Filed Date | 2022-08-11 |
United States Patent
Application |
20220256541 |
Kind Code |
A1 |
Larsson; Daniel ; et
al. |
August 11, 2022 |
CIF-Value to Component Carrier Mapping Reconfiguration
Abstract
A radio network node in a multi-carrier radio communication
system reconfigures mappings of Carrier Indicator Field values
(CIF-values) to component carriers. Each CIF-value is mapped to a
respective component carrier comprising a respective shared data
channel and a downlink control channel that addresses the shared
data channel. The reconfiguring comprises maintaining a first
mapping between a first CIF-value and a first component carrier.
The downlink control channel of the first component carrier carries
the first CIF-value and a second CIF-value. The reconfiguring
further comprises changing a second mapping of the second CIF-value
to a second component carrier. The radio network node sends the
changed second mapping to a user equipment (UE) comprised in the
multi-carrier radio communication system. The UE receives the
reconfigured mappings and reconfigures the UE to use the mappings
for communication in the multi-carrier radio communication
system.
Inventors: |
Larsson; Daniel; (Lund,
SE) ; Baldemair; Robert; (Solna, SE) ;
Gerstenberger; Dirk; (Stockholm, SE) ; Parkvall;
Stefan; (Bromma, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
1000006292421 |
Appl. No.: |
17/730806 |
Filed: |
April 27, 2022 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14806054 |
Jul 22, 2015 |
|
|
|
17730806 |
|
|
|
|
12886031 |
Sep 20, 2010 |
9124412 |
|
|
14806054 |
|
|
|
|
61286138 |
Dec 14, 2009 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/042 20130101;
H04W 72/0453 20130101; H04L 5/0094 20130101; H04L 5/0064 20130101;
H04L 27/2601 20130101; H04L 5/0096 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 27/26 20060101 H04L027/26; H04L 5/00 20060101
H04L005/00 |
Claims
1. A method, implemented by a radio network node in a multi-carrier
radio communication system, the method comprising: reconfiguring
mappings of Carrier Indicator Field values (CIF-values) to
component carriers, each CIF-value being mapped to a respective
component carrier comprising a respective shared data channel and a
downlink control channel that addresses the shared data channel,
the reconfiguring comprising: maintaining a first mapping between a
first CIF-value and a first component carrier, the downlink control
channel of the first component carrier carrying the first CIF-value
and a second CIF-value; and changing a second mapping of the second
CIF-value to a second component carrier; sending the changed second
mapping to a user equipment comprised in the multi-carrier radio
communication system.
2. The method of claim 1, wherein the first component carrier
corresponds to a primary cell and is managed by the radio network
node.
3. The method of claim 1, wherein the first CIF-value is equal to
zero.
4. The method of claim 1, wherein sending the changed second
mapping comprises refraining from sending the maintained first
mapping to the user equipment.
5. The method of claim 1, wherein the downlink control channel of
the first component carrier is a Physical Downlink Control Channel
and the shared data channel of the first component carrier is a
Physical Downlink Shared Channel or a Physical Uplink Shared
Channel.
6. The method of claim 1, wherein the sending of the changed second
mapping is performed using Radio Resource Control protocol.
7. An arrangement comprised in a radio network node configured to
operate in a multi-carrier radio communication system, the
arrangement comprising: processing circuitry configured to
reconfigure mappings of Carrier Indicator Field values (CIF-values)
to component carriers, each CIF-value being mapped to a respective
component carrier comprising a respective shared data channel and a
downlink control channel that addresses the shared data channel,
wherein to reconfigure the mapping, the processing circuitry is
configured to: maintain a first mapping between a first CIF-value
and a first component carrier, the downlink control channel of the
first component carrier carrying the first CIF-value and a second
CIF-value; and change a second mapping of the second CIF-value to a
second component carrier; a transceiver communicatively coupled to
the processing circuitry and configured to send the changed second
mapping to a user equipment comprised in the multi-carrier radio
communication system.
8. The arrangement of claim 7, wherein the first component carrier
corresponds to a primary cell managed by the radio network
node.
9. The arrangement of claim 7, wherein the first CIF-value is equal
to zero.
10. The arrangement of claim 7, wherein to send the changed second
mapping, the transceiver is configured to refrain from sending the
maintained first mapping to the user equipment.
11. The arrangement of claim 7, wherein the downlink control
channel of the first component carrier is a Physical Downlink
Control Channel and the shared data channel of the first component
carrier is a Physical Downlink Shared Channel or a Physical Uplink
Shared Channel.
12. The arrangement of claim 7, wherein to send the changed second
mapping, the transceiver is configured to use Radio Resource
Control protocol.
13. A method, implemented in a User Equipment (UE) in a
multi-carrier radio communication system, the method comprising:
receiving mappings of Carrier Indicator Field values (CIF-values)
to component carriers, each CIF-value being mapped to a respective
component carrier comprising a respective shared data channel and a
downlink control channel that addresses the shared data channel,
the mappings having been reconfigured by a radio network node in
the multi-carrier radio communication system such that: a first
mapping between a first CIF-value and a first component carrier is
maintained, the downlink control channel of the first component
carrier carrying the first CIF-value and a second CIF-value; and a
second mapping of the second CIF-value is changed to a second
component carrier; reconfiguring the UE to use the reconfigured
mappings for communication in the multi-carrier radio communication
system.
14. The method of claim 13, wherein the first CIF-value corresponds
to a primary cell managed by the radio network node.
15. The method of claim 13, wherein the first CIF-value is equal to
zero.
16. The method of claim 13, wherein the downlink control channel of
the first component carrier is a Physical Downlink Control Channel
and the shared data channel of the first component carrier is a
Physical Downlink Shared Channel or a Physical Uplink Shared
Channel.
17. The method of claim 13, wherein receiving the reconfigured
mapping is performed using Radio Resource Control protocol.
18. A User Equipment (UE) configured to operate in a multi-carrier
radio communication system, the UE comprising: receiver circuitry
configured to receive mappings of Carrier Indicator Field values
(CIF-values) to component carriers, each CIF-value being mapped to
a respective component carrier comprising a respective shared data
channel and a downlink control channel that addresses the shared
data channel, the mappings having been reconfigured by a radio
network node in the multi-carrier radio communication system such
that: a first mapping between a first CIF-value and a first
component carrier is maintained, the downlink control channel of
the first component carrier carrying the first CIF-value and a
second CIF-value; and a second mapping of the second CIF-value is
changed to a second component carrier; processing circuitry
communicatively coupled to the receiver circuitry and configured to
reconfiguring the UE to use the reconfigured mappings for
communication in the multi-radio communication system.
19. The UE of claim 18, wherein the first CIF-value corresponds to
a primary cell managed by the radio network node.
20. The UE of claim 18, wherein the first CIF-value is equal to
zero.
21. The UE of claim 18, wherein the downlink control channel of the
first component carrier is a Physical Downlink Control Channel and
the shared data channel of the first component carrier is a
Physical Downlink Shared Channel or a Physical Uplink Shared
Channel.
22. The UE of claim 18, wherein to receive the mappings, the
receiver circuitry is configured to use Radio Resource Control
protocol.
Description
RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/806,054, filed on Jul. 22, 2015, which is a
continuation of U.S. patent application Ser. No. 12/886,031, filed
on Sep. 20, 2010, and issued as U.S. Pat. No. 9,124,412 on Sep. 1,
2015, which claims benefit of U.S. Provisional Application No.
61/286,138, filed on Dec. 14, 2009, the disclosures of each of
which are herein incorporated by reference in their entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to a method and an
arrangement in a multi-carrier radio communication system. In
particular, the present disclosure relates to a method and an
arrangement in a radio network node for reconfiguring mappings from
Carrier Indicator Field-values to component carriers.
BACKGROUND
[0003] LTE (Long Term Evolution) uses OFDM (Orthogonal Frequency
Division Multiplexing) in the downlink and DFT-spread OFDM
(Discrete Fourier Transform spread Orthogonal Frequency Division
Multiplexing) in the uplink. The basic LTE downlink physical
resource can thus be seen as a time-frequency grid as illustrated
in FIG. 1, where each resource element corresponds to one OFDM
subcarrier during one OFDM symbol interval.
[0004] In the time domain, LTE downlink transmissions are organized
into radio frames of 10 ms, each radio frame consisting of ten
equally-sized subframes of length Tsubframe=1 ms as seen in FIG.
2.
[0005] Furthermore, the resource allocation in LTE is typically
described in terms of resource blocks, where a resource block
corresponds to one slot (0.5 ms) in the time domain and 12
contiguous subcarriers in the frequency domain. Resource blocks are
numbered in the frequency domain, starting with 0 from one end of
the system bandwidth.
[0006] Downlink transmissions are dynamically scheduled, in that in
each subframe (or transmission time interval, TTI) the base station
transmits control information about to which terminals data is
transmitted and upon which resource blocks the data is transmitted,
in the current downlink subframe. This control signaling is
typically transmitted in the first 1, 2, 3 or 4 OFDM symbols in
each subframe. A downlink system with 3 OFDM symbols as control is
illustrated in FIG. 3.
[0007] To transmit data in the uplink the mobile terminal has to
have been first assigned an uplink resource for data transmission,
on the Physical Uplink Shared Channel (PUSCH). In contrast to a
data assignment in downlink, in uplink the assignment of resource
blocks must always be consecutive in frequency, to retain the
single carrier property of the uplink as illustrated in FIG. 4.
[0008] The LTE Rel-8 standard has recently been standardized,
supporting bandwidths up to 20 MHz. However, in order to meet the
upcoming IMT-Advanced requirements, 3GPP has initiated work on
LTE-Advanced. One of the parts of LTE-Advanced is to support
bandwidths larger than 20 MHz. One important requirement on
LTE-Advanced is to assure backward compatibility with LTE Rel-8.
This should also include spectrum compatibility. That would imply
that an LTE-Advanced carrier, wider than 20 MHz, should appear as a
number of LTE carriers to an LTE Rel-8 terminal. Each such carrier
can be referred to as a component carrier (CC). In particular for
early LTE-Advanced deployments it can be expected that there will
be a smaller number of LTE-Advanced-capable terminals compared to
many LTE legacy terminals. Therefore, it is necessary to assure an
efficient use of a wide carrier also for legacy terminals, i.e.,
that it is possible to implement carriers where legacy terminals
can be scheduled in all parts of the wideband LTE-Advanced carrier.
The straightforward way to obtain this would be by means of carrier
aggregation. Carrier aggregation implies that an LTE-Advanced
terminal can receive multiple component carriers, where the
component carriers have, or at least the possibility to have, the
same structure as a Rel-8 carrier. Carrier aggregation is
illustrated in FIG. 5.
[0009] The number of aggregated component carriers as well as the
bandwidth of the individual component carrier may be different for
uplink and downlink. A symmetric configuration refers to the case
where the number of component carriers in downlink and uplink is
the same, whereas an asymmetric configuration refers to the case
that the number of component carriers is different. It is important
to note that the number of component carriers configured in a cell
may be different from the number of component carriers seen by a
terminal: A terminal may, for example, support more downlink
component carriers than uplink component carriers, even though the
cell is configured with the same number of uplink and downlink
component carriers.
[0010] Scheduling of the component carriers is done on the Physical
Downlink Control Channel (PDCCH) via downlink assignments. Uplink
grants are also signaled via PDCCH. Control information on the
PDCCH is formatted as a Downlink Control Information (DCI) message.
DCI messages for downlink assignments contain among others resource
block assignment, modulation and coding scheme related parameters,
hybrid-ARQ redundancy version, etc. In addition to those parameters
that relate to the actual downlink transmission most DCI formats
for downlink assignments also contain a bit field for Transmit
Power Control (TPC) commands. These TPC commands are used to
control the uplink power control behavior of the corresponding
PUCCH that is used to transmit the hybrid-ARQ feedback.
[0011] The design of PDCCH in LTE Rel-10 follows very much that one
in Rel-8/9. Assignments and grants of each component carrier are
separately encoded and transmitted within a separate PDCCH. Main
motivation for choosing separately encoded PDCCH over a jointly
encoded PDCCH--here DCI messages from multiple component carriers
would be lumped together into one entity, jointly encoded and
transmitted in a single PDCCH--was simplicity.
[0012] In LTE Rel-10, the PDCCH is extended to include a Carrier
Indicator Field (CIF), which is not present in LTE Rel-8/9. The CIF
may consist of three bits attached to the DCI message which points
to that component carrier the corresponding shared channel is
located at. For a downlink assignment the CIF points to the
component carrier carrying the PDSCH whereas for an uplink grant
the three bits are used to address the component carrier conveying
Physical Uplink Shared Channel (PUSCH). For simplicity this field
is always three bits.
[0013] If CIF is configured, every downlink assignment and uplink
grant contains the CIF bits, even if the assignment addresses PDSCH
within the component carrier (or PUSCH within the linked uplink
component carrier for uplink grants). With no CIF configured, the
carrier aggregation looks like multiple parallel Rel-8/9 carriers,
see FIG. 7. FIG. 8 shows the relation between PDCCH and PDSCH with
configured CIF. A terminal configured with more uplink component
carriers than downlink component carriers always requires an uplink
grant with CIF.
[0014] The mapping of the CIF to component carriers could be done
according to one of two different possibilities: [0015]
cell-specific mapping, i.e., the same mapping from CIF value to
component carrier number is used by all user equipments (UEs) in
the cell. The mapping could either be given according to rules or
tables in the upcoming Rel-10 specifications or be signaled as part
of the system information in the cell. With a cell-specific
approach, the mapping is expected to be fixed or changed very
infrequently. [0016] UE-specific mapping, i.e. each user equipment
(UE) has its own mapping from CIF to component carrier number. In
this case, the CIF-to-component-carrier mapping is signaled as part
of the UE-specific configuration information. Changing the mapping
can, in this alternative, be more frequent than in the
cell-specific alternative.
[0017] Over time the user equipment will have the possibility to
receive or transmit data on different component carriers, but not
necessarily on all component carriers that a radio network node,
such as an eNB, transmits in its cell(s). If the user equipment
were required to receive all component carriers transmitted by the
radio network node, this would result in short battery time and
more memory consumption, for example. Furthermore, the radio
network node has also the possibility to turn off component
carriers, e.g., to enable power saving.
[0018] If UE-specific CIF-to-CC mapping is used, a problem will
occur when the mapping from CIF-values to component carriers is
updated. During updating of the mapping, the radio network node
sends the reconfigured mappings to the user equipment and the
network cannot communicate with the user equipment. This may lead
to lost calls and degraded performance.
SUMMARY
[0019] An object may be to improve performance of connection to
user equipments during updating of mapping from CIF-values to
component carrier.
[0020] According to an aspect, the object is achieved by a method
in a radio network node for reconfiguring mappings from Carrier
Indicator Field-values, referred to as "CIF-values", to component
carriers. Each CIF-value is mapped to a respective component
carrier comprising a respective shared data channel. Each
respective shared data channel corresponds to at least one downlink
control channel carrying said each CIF-value. The component
carriers are managed by the radio network node. The radio network
node and the user equipment are comprised in a multi-carrier radio
communication system. In an initial step, the radio network node
reconfigures mappings from CIF-values to component carriers, while
at least one mapping of CIF-value to component carrier is
maintained. The component carrier of said at least one mapping from
CIF-value to component carrier comprises said at least one downlink
control channel and a shared data channel corresponding to said at
least one downlink control channel. Further, the radio network node
sends at least one of the reconfigured mappings from CIF-values to
component carriers to the user equipment.
[0021] According to another aspect, the object is achieved by an
arrangement in a radio network node for reconfiguring mappings from
Carrier Indicator Field-values to component carriers. Each
CIF-value is mapped to a respective component carrier comprising a
respective shared data channel. Each respective shared data channel
corresponds to at least one downlink control channel carrying said
each CIF-value. The component carriers are managed by the radio
network node. The radio network node and the user equipment are
comprised in a multi-carrier radio communication system. The
arrangement may comprise a reconfiguring circuit configured to
reconfigure mappings from CIF-values to component carriers, while
at least one mapping of CIF-value to component carrier is
maintained. The component carrier of said at least one mapping from
CIF-value to component carrier comprises said at least one downlink
control channel and a shared data channel corresponding to said at
least one downlink control channel. The arrangement may further
comprise a transceiver configured to send at least one of the
reconfigured mappings from CIF-values to component carriers to the
user equipment.
[0022] Thanks to the fact that the mapping of CIF-value to
component carrier is sent to the user equipment while at least one
mapping of CIF-value to component carrier is maintained, the user
equipment may continue to transmit on the component carrier
corresponding to said at least one mapping of CIF-value to
component carrier. As a result, improved performance of connection
to the user equipment during updating of mapping from CIF-value to
component carrier is achieved.
[0023] Expressed differently, mapping of one CIF-value to one
component carrier is fixed, i.e., not changed during
reconfiguration (or determination) of the CIF-CC-mapping. In this
manner, there will be a component carrier available for
transmission even during updating of the mapping from CIF-value to
component carrier. As a result, a user equipment may
transmit/receive continuously by use of the component carrier
associated to the CIF-value whose interpretation is kept even
though the CIF-CC-mapping is updated for other CIF-values.
[0024] An advantage is that the number of lost calls/connections
during updating of the CIF-CC-mapping in the user equipment may be
reduced. Moreover, degraded connection performance due to updating
of mapping from CIF-values to component carriers may be
avoided.
[0025] Further features of, and advantages with, embodiments of the
present invention will become apparent when studying the appended
claims and the following description. It is to be understood that
different features of embodiments according to the present
invention may be combined to create embodiments other than those
described in the following, without departing from the scope of the
present invention, which is defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The various aspects of the embodiments disclosed herein,
including its particular features and advantages, will be readily
understood from the following detailed description and the
accompanying drawings, in which:
[0027] FIG. 1 illustrates schematically an LTE downlink physical
resource;
[0028] FIG. 2 illustrates schematically an LTE time-domain
structure;
[0029] FIG. 3 illustrates schematically a Downlink subframe;
[0030] FIG. 4 illustrates schematically a PUSCH resource
assignment;
[0031] FIG. 5 illustrates carrier aggregation,
[0032] FIG. 6 shows a schematic overview of an exemplifying radio
communication system in which the present solution may be
implemented,
[0033] FIG. 7 shows five exemplifying component carriers, in which
no CIF is configured in the DCI message of the downlink control
channel,
[0034] FIG. 8 shows three exemplifying component carriers, in which
CIF2 is mapped to component carrier f3,
[0035] FIG. 9 shows two exemplifying component carriers, in which
CIF2 is mapped to component carrier f1,
[0036] FIG. 10 shows a schematic, combined signalling and flow
chart of an embodiment of a method in the radio communication
system according to FIG. 6 for reconfiguring mappings from Carrier
Indicator Field-values to component carriers,
[0037] FIG. 11 shows a schematic flow chart of an embodiment of the
method in the radio network node for reconfiguring mappings from
Carrier Indicator Field-values to component carriers, and
[0038] FIG. 12 shows a schematic block diagram of an embodiment of
the arrangement in the radio network node.
DETAILED DESCRIPTION
[0039] Throughout the following description similar reference
numerals have been used to denote similar elements, parts, nodes,
systems, items or features, when applicable.
[0040] In FIGS. 7, 8 and 9, there are shown different examples of
component carriers with CIF enabled and with CIF disabled. In FIG.
7, the CIF is disabled, whereas in FIGS. 8 and 9, the CIF is
enabled. Moreover, FIG. 8 shows a configuration, where the
CIF-value to component carrier mapping is different from the
CIF-value to component carrier mapping shown by the configuration
depicted in FIG. 9.
[0041] FIG. 6 shows a schematic overview of an exemplifying
multi-carrier radio communication system 100, in which embodiments
may be implemented. The multi-carrier radio communication system
100 comprises a radio network node 130 and a user equipment 120.
The arrow indicates that the user equipment 120 may exchange
information with the radio network node 130 using, for example, a
downlink control channel such as PDCCH, and a shared data channel
such as PDSCH or PUSCH.
[0042] FIG. 7 shows five exemplifying component carriers f1, f2,
f3, f4, f5, in which no CIF is configured in the DCI message of the
downlink control channel. As shown in FIG. 5, an radio
communication system, such as LTE-Advance, may use an aggregated
carrier, comprising five component carrier of 20 MHz each. In FIG.
7, it may be seen that each component carrier has its own
separately encoded PDCCH. In the enlarged view of the PDCCH, it is
shown that the Downlink Control Information (DCI) message does not
include a CIF-value. Since no CIF is used, PDCCH points to PDSCH
allocated on the same component carrier as indicated by the
arrows.
[0043] FIG. 8 shows three exemplifying component carriers f1, f2,
f3, in which CIF2 is mapped to component carrier f3. In FIG. 8, the
DCI message, as shown by the enlarged view, comprises a CIF-value.
Hence, CIF is enabled. Downlink assignments transmitted in one
component carrier may point to PDSCH within another component
carrier. In this case, the CIF-value of PDCCH of component carrier
f2 cross-schedules to a PDSCH of a component carrier f3. See arrows
between component carrier f2 and component carrier f3.
[0044] It may be noted that mapping from CIF-value to component
carrier may be realized in the form of a table or matrix, where for
example a row comprising one CIF-value and one component carrier
indicates that this particular CIF-value is mapped to the component
carrier on that row. Hence, one or more pairs, wherein each pair
comprises one CIF-value and one corresponding component carrier,
are formed to express the mapping from CIF-values to component
carriers. Thus, one mapping refers to one such pair comprising a
CIF-value and a component carrier (or rather component carrier
number for indicating a component carrier).
[0045] In FIG. 9, the CIF-values of the situation in FIG. 8 have
been reconfigured. The radio network node 130 has also decided to
switch off (shut down) component carrier f3. Now CIF-value CIF2 is
mapped to a component carrier f1 as indicated by the arrows. In
FIG. 8, CIF-value CIF2 was mapped to component carrier f3. Notably,
CIF-value CIF1 is kept, i.e. points to component carrier f2 in both
FIGS. 8 and 9, such that this CIF-value and the respective
component carrier f2 may be used by the user equipment 120 during
updating of mappings from CIF-value to component carrier.
[0046] In FIG. 10, there is shown a schematic, combined signalling
and flow chart of an embodiment of a method in the radio
communication system 100 according to FIG. 6 for reconfiguring
mappings from Carrier Indicator Field-values to component
carriers.
[0047] Each CIF-value is mapped to a respective component carrier
comprising a respective shared data channel. Each respective shared
data channel corresponds to at least one downlink control channel
carrying (or comprising) said each CIF-value. The component
carriers are managed by the radio network node 130. The radio
network node 130 and the user equipment 120 are comprised in a
multi-carrier radio communication system 100. The following steps
may be performed. Notably, in some embodiments of the method the
order of the steps may differ from what is indicated below.
[0048] 210: The radio network node 130 reconfigures mappings from
CIF-values to component carriers, while maintaining at least one
mapping of CIF-value to component carrier. The component carrier of
said at least one mapping from CIF-value to component carrier
comprises said at least one downlink control channel and a shared
data channel corresponding to said at least one downlink control
channel.
[0049] 220: The user equipment 120 receives at least one of the
reconfigured mappings from CIF-values to component carriers from
radio network node 130.
[0050] The present solution enables the radio network node 130,
such as an eNB, to always have the possibility to schedule data on
the component carrier that carries PDCCH and PDSCH (or the anchor
carrier, also referred to as primary cell). Hence, the radio
network node 130 may schedule the user equipment even when it is
reconfiguring all its other CIF-to-component carrier mappings. In
some embodiments, this also enables lower signaling overhead on the
Radio Resource Control protocol and avoids drop of communication
between the user equipment 120 and the radio network node 130
during updating of mapping. In a scenario where the user equipment
has initiated hand-over directly before updating of mapping, the
user equipment may need to transmit with high power in order to
keep connection. In such a scenario, embodiments avoid extensive
user equipment battery consumption and/or unnecessary user
equipment memory usage.
[0051] FIG. 11 illustrates an exemplifying method in a radio
network node 130 for reconfiguring mappings from Carrier Indicator
Field-values to component carriers. The flow chart of FIG. 11
corresponds to the combined signalling and flow chart of FIG. 10.
Where applicable the same reference numerals have been used. Each
CIF-value is mapped to a respective component carrier comprising a
respective shared data channel. Each respective shared data channel
corresponds to at least one downlink control channel carrying (or
comprising) said each CIF-value. The component carriers are managed
by the radio network node 130. The radio network node 130 and the
user equipment 120 are comprised in a multi-carrier radio
communication system 100. The following steps may be performed.
Notably, in some embodiments of the method the order of the steps
may differ from what is indicated below.
[0052] 210: The radio network node 130 reconfigures mappings from
CIF-values to component carriers, while maintaining at least one
mapping of CIF-value to component carrier. The component carrier of
said at least one mapping from CIF-value to component carrier
comprises said at least one downlink control channel and a shared
data channel corresponding to said at least one downlink control
channel.
[0053] 220: The radio network node 130 sends at least one of the
reconfigured mappings from CIF-values to component carriers to the
user equipment 120.
[0054] In some embodiments of the method in the network node 130,
wherein the component carrier of said at least one mapping from
CIF-value to component carrier corresponds to a primary cell,
wherein the primary cell is one of the component carriers managed
by the radio network node 130. An advantage may be that, from a
user equipment perspective, channel quality may be better on the
primary cell as compared to other cells.
[0055] In some embodiments of the method in the network node 130,
the CIF-value of said at least one mapping from CIF-value to
component carrier is equal to zero.
[0056] In some embodiments of the method in the network node 130,
the sending 230 of the configured mapping further comprises
refraining 230 from sending said at least one mapping from
CIF-value to component carrier to the user equipment 120. As a
consequence, said at least one mapping from CIF-value to component
carrier may need to be predetermined. An advantage may be that less
information needs to be sent from the radio network node 130 to the
user equipment 120.
[0057] In some embodiments of the method in the network node 130,
the control channel is PDCCH and the shared data channel is PDSCH
or PUSCH in case the multi-carrier radio communication system is an
LTE system. Hence, it may be noted that embodiments presented
herein may be applicable to both downlink assignments and uplink
grants.
[0058] In some embodiments of the method in the network node 130,
the step of sending at least some of the reconfigured mappings is
performed using Radio Resource Control protocol, sometimes referred
to as RRC-protocol.
[0059] Now referring to FIG. 12, there is illustrated an
arrangement 400 in the radio network node 130 configured to perform
the method described above. The arrangement 400 is, hence,
configured to reconfigure mappings from Carrier Indicator
Field-values to component carriers. Each CIF-value is mapped to a
respective component carrier comprising a respective shared data
channel. Each respective shared data channel corresponds to at
least one downlink control channel carrying said each CIF-value.
The component carriers are managed by the radio network node 130.
The radio network node 130 and the user equipment 120 are comprised
in a multi-carrier radio communication system 100. The arrangement
400 may comprise a reconfiguring circuit 410 configured to
reconfigure mappings from CIF-values to component carriers, while
maintaining at least one mapping of CIF-value to component carrier.
The reconfiguring circuit 410 may be a processing circuit/unit, a
processor, an application specific integrated circuit (ASIC), a
field-programmable gate array (FPGA) or the like. The component
carrier of said at least one mapping from CIF-value to component
carrier comprises said at least one downlink control channel and a
shared data channel corresponding to said at least one downlink
control channel. The arrangement 400 further comprises a
transceiver 420 configured to send at least one of the reconfigured
mappings from CIF-values to component carriers to the user
equipment 120. Moreover, the arrangement 400 may comprise a memory
430 for storing software to be executed by, for example, the
processor. The software may comprise instructions to enable the
processor to perform the method described above.
[0060] In some embodiments of the arrangement 400 in the radio
network node 130, the transceiver 420 may be a sending/receiving
unit or may comprise a transmitter and/or a receiver as
appropriate.
[0061] In some embodiment of the arrangement 400 in the radio
network node 130, wherein the component carrier of said at least
one mapping from CIF-value to component carrier corresponds to a
primary cell, wherein the primary cell is one of the component
carriers managed by the radio network node 130. An advantage may be
that, from a user equipment perspective, channel quality may be
better on the primary cell as compared to other cells.
[0062] In some embodiment of the arrangement 400 in the radio
network node 130, the CIF-value of said at least one mapping from
CIF-value to component carrier is equal to zero.
[0063] In some embodiment of the arrangement 400 in the radio
network node 130, the transceiver 420 further is configured to
refrain from sending said at least one mapping from CIF-value to
component carrier to the user equipment 120. As a consequence, said
at least one mapping from CIF-value to component carrier may need
to be predetermined. An advantage may be that less information
needs to be sent from the radio network node 130 to the user
equipment 120.
[0064] In some embodiment of the arrangement 400 in the radio
network node 130, the control channel is PDCCH and the shared data
channel is PDSCH or PUSCH
[0065] In some embodiment of the arrangement 400 in the radio
network node 130, the transceiver 420 may further be configured to
use Radio Resource Control protocol when sending at least some of
the reconfigured mappings to the user equipment 120.
[0066] According to some embodiments, the mapping of one of the CIF
values should be fixed, so that is not possible to reconfigure the
component carrier that carries both the PDCCH and PDSCH (e.g.
component carrier f2 in FIGS. 8 and 9).
[0067] In an example of an embodiment, the interpretation of one
CIF value is fixed by the specification, i.e. not reconfigurable,
to point to the same component carrier that the PDCCH is
transmitted upon. The fixed CIF value may be either defined by the
standard, e.g. always CIF=0, or may be configured to the same value
for all UEs through RRC signaling (broadcast or dedicated
signaling). In one example this component carrier would correspond
to a value of CIF=0. Hence, even during the reconfiguration period,
one CIF value may be used without ambiguity and hence there is
always a possibility for the network to communicate with the
terminal.
[0068] In an example of an embodiment, the interpretation of one
CIF value is fixed to point to a predefined component carrier, e.g.
the so-called anchor carrier. The anchor carrier is a component
carrier which the UE always has to monitor (subject to any
Discontinuous Transmission cycle, abbreviated as DTX cycle), e.g.
for receiving system information. The anchor carrier may also be
referred to as the primary cell according to 3GPP-terminology.
[0069] Even though a number of embodiments of the present invention
have been described, many different alterations, modifications and
the like will become apparent for those skilled in the art. The
described embodiments are therefore not intended to limit the scope
of the invention, which is defined by the appended claims.
* * * * *