APERIODIC INFORMATION TRANSMISSION
TECHNICAL FIELD
The present invention relates to carrier aggregation systems, and more specifically, to
triggering and reporting methods and apparatuses of aperiodic channel state-related
information for a carrier aggregation system.
DESCRIPTION OF THE RELATEDART
LTE-Advanced has introduced carrier aggregation technology in order to support
operation within higher bandwidths. Carrier aggregation can jointly serve User Equipment
(UE) by aggregating several discrete frequency bands. In consideration of backward
compatibility of LTE, LTE-Advanced has introduced the concept of component carrier
(referred to as CC for short). In LTE, each cell has only one CC, and each UE also has only
one CC that serves this UE. In LTE-Advanced, however, each cell has multiple CCs, and
each UE may have multiple CCs that serve this UE. Due to the introduction of carrier
aggregation technology into LTE-Advanced, scheduling (or triggering) of aperiodic
information in LTE-Advanced becomes more complex, and can not reuse existing
mechanisms in LTE.
Specifically, in LTE-Advanced, multiple CCs (up to 5 CCs are allowed at present) may
be configured for each cell, and each UE also may use multiple CCs. However, not all UE
will use all CCs in a cell where they are located. CCs that are used by UE are referred to as
configured CCs, and unused ones are referred to as non-configured CCs. Different UE
might have different configured/non-configured CCs. Configured CCs may further be
divided into activated CCs and deactivated CCs. UE transmits data on activated CCs and
performs no data transmission on deactivated CCs. For each UE, the number of configured
or activated uplink component carriers (UL CCs) may be either equal to (this case is referred
to as symmetric carrier aggregation) or different from (this case is referred to as asymmetric
carrier aggregation) that of configured or activated downlink component carriers (DL CCs).Regarding scheduling, Node B (eNB) may schedule on one DL CC data or control
information transmission on the paired UL CC, or data or control information transmission on
other UL CC (i.e., unpaired UL CC) (this case is referred to as cross scheduling).
In view of the asymmetric carrier aggregation, cross-carrier scheduling and carrier
activation/deactivation mechanisms used in the above-described LTE-Advanced systems,
scheduling technology for aperiodic information transmission as used in LTE is no longer
suitable for LTE-Advanced systems. The aperiodic information transmission comprises, for
example, aperiodic Channel Quality Indicator (referred to as COI for short) reporting or
aperiodic uplink sounding reference signal (SRS) transmission.
Specifically, since there is only one CC in LTE, it is possible to indicate scheduling of
aperiodic channel state information (referred to as CSI for short) reports simply through one
bit in DCI format 0. For example, in LTE Rel-8, CSI reports are scheduled (or triggered)
through a CQI request bit in DCI format 0. The CSI comprises, for example, Channel
Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and ohter
information. However, such mehtod is not suitable for LTE-Advanced systems that use
carrier aggretaion technology. Therefore, there is a need for a new mechanism for aperiodic
CSI reporting and aperiodic SRS transmission which is suitable for LTE-Advanced.
In the last RANl-#61bis meeting, the discussion on aperiodic CSI reporting was
focused on the transmission of aperiodic CSI reports, i.e., selecting which UL CC to convey
aperiodic CSI reports. There are only limited discussions on another issue of aperiodic CSI
reporting, i.e., a mechanism for triggering aperiodic CSI reporting provided for multiple DL
CCs.
Nowadays there are proposed some ways of triggering aperiodic CSI reporting for
multiple DL CCs (i.e., carrier aggregation) by using uplink grants (UL grant). For example,
various methods of using one UL grant to trigger aperiodic CSI reporting for one DL CC are
proposed in RI- 103684, which are briefed as below.
1. CQI triggering by SIB2-linkage. In this solution, the CSI report for one DL CC can
only be triggered by a UL grant on the same CC. Furthermore, the UL grant is transmitted
on the SIB2-linked UL CC.
For the case where the SIB2-linked UL CC is not configured for a UE, some
modifications would be required. For example, it may be possible to map the carrier
indicator field (referred to as CIF for short) to the CC that requires a CSI report (referred to asCSI-CC for short).
2. CSI scanning. A UL grant triggers consecutive CSI reports that scan through all
DL CCs, on a periodic basis.
3. Explicit mapping. An m-bit CSI fields is added to the UL DCI format (the uplink
grant is carried in the UL DCI format) to indicate the CSI-CC that is conveyed on the PUSCH,
where m can be 3 bits. Note that this is similar to the CIF field for cross-CC scheduling, but
in this case the m-bit CSI field is used for CSI-CC indication.
4. The CSI-CC field is jointly encoded with a 1-bit CQI trigger. In this case,
m - 2 ( + ) -g a e
needed to jointly indicate the CSI triggering and the CSI-CC index,
where denotes the number of activated DLCCs.
For detailed information of the above solutions, please refer to Rl-103694, "UCI
transmission on PUSCH for carrier aggregation," TI, which is incorporated into here by
reference.
However, the above methods only can trigger the aperiodic CSI reporting for one DL
CC by using one uplink grant. As mentioned in Rl-103694, triggering one aperiodic CSI
reporting for one DL CC limits the CSI feedback payload. Furthermore, since multiple
uplink grants are needed to be sent while triggering aperiodic CSI reporting for multiple DL
CCs, this increases overhead for uplink grants and also increases feedback delay for CSI
reporting of all activated DL CCs.
On the other hand, there is currently proposed a solution for triggering aperiodic CSI
reporting for all DL CCs by using one uplink grant. In this solution, not only CSI reporting
for involved DL CCs is triggered, but also CSI reporting for other undesired DL CCs is
triggered. Therefore, this incurs large CSI reporting overhead and undifferentiated reporting
manners.
Triggering of aperiodic SRS transmission contains similar problems to triggering of
aperiodic CSI reporting.
SUMMARY OF THE INVENTION
In view of the existing problems in the prior art, embodiments of the present inventionprovide improved processing methods and apparatuses of aperiodic information transmission
for a carrier aggregation system.
According to an embodiment of the present invention, there is provided a triggering
method of aperiodic channel state information CSI for a carrier aggregation system,
comprising:
(1) pre-assigning a corresponding relationship between bits of the CSI request field in
an uplink grant and multiple downlink component carriers DL CCs of user equipment,
wherein the number of bits of the CSI request field is greater than 1 and less than the
maximum allowed number of DL CCs in the system;
(2) determining the DL CC for which aperiodic CSI reporting is to be triggered; and
(3) mapping the CSI request field in the uplink grant according to the pre-assigned
corresponding relationship to mark the value of the bit corresponding to the determined DL
CC as "trigger".
According to another embodiment of the present invention, there is provided a
reporting method of aperiodic channel state information CSI for a carrier aggregation system,
comprising:
(1) pre-assigning a corresponding relationship between bits of the CSI request field in
an uplink grant and multiple downlink component carriers DL CCs of user equipment,
wherein the number of bits of the CSI request field is greater than 1 and less than the
maximum allowed number of DL CCs in the system; and
(2) demapping, according to the pre-assigned corresponding relationship, the CSI
request field in the received uplink grant so as to determine the DL CC for which aperiodic
CSI reporting will be implemented.
According to another embodiment of the present invention, there is provided a
triggering apparatus of aperiodic channel state information CSI for a carrier aggregation
system, comprising:
first pre-assigning means, for pre-assigning a corresponding relationship between bits
of the CSI request field in an uplink grant and multiple downlink component carriers DL CCs
of user equipment, wherein the number of bits of the CSI request field is greater than 1 and
less than the maximum allowed number of DL CCs in the system;
first determining means, for determining the DL CC for which aperiodic CSI reportingis to be triggered; and
mapping means, for mapping the CSI request field in the uplink grant according to the
pre-assigned corresponding relationship to mark the value of a bit corresponding to the
determined DL CC as "trigger".
According to another embodiment, there is provided a reporting apparatus of aperiodic
channel state information CSI for a carrier aggregation system, comprising:
second pre-assigning means, for pre-assigning a corresponding relationship between
bits of the CSI request field in an uplink grant and multiple downlink component carriers DL
CCs of user equipment, wherein the number of bits of the CSI request field is greater than 1
and less than the maximum allowed number of DL CCs in the system; and
second determining means, for demapping, according to the pre-assigned
corresponding relationship, the CSI request field in the received uplink grant so as to
determine the DL CC for which aperiodic CSI reporting will be implemented.
According to another embodiment of the present invention, there is provided a
triggering method of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the SRS request field in
an uplink grant and multiple uplink component carriers UL CCs of user equipment, wherein
the number of bits of the SRS request field is greater than 1 and less than the maximum
allowed number of UL CCs in the system;
(2) determining the UL CC for which aperiodic SRS is to be triggered; and
(3) mapping the SRS request field in the uplink grant according to the pre-assigned
corresponding relationship to mark the value of a bit corresponding to the determined UL CC
as "trigger".
According to another embodiment of the present invention, there is provided a
transmission method of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the SRS request field in
an uplink grant and multiple uplink component carriers UL CCs of user equipment, wherein
the number of bits of the SRS request field is greater than 1 and less than the maximum
allowed number of UL CCs in the system; and(2) demapping, according to the pre-assigned corresponding relationship, the SRS
request field in the received uplink grant so as to determine the UL CC for which SRS
transmission will be implemented.
According to another embodiment of the present invention, there is provided a
triggering apparatus of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
third pre-assigning means, for pre-assigning a corresponding relationship between bits
of the SRS request field in an uplink grant and multiple uplink component carriers UL CCs of
user equipment, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system;
third determining means, for determining the UL CC for which aperiodic SRS is to be
triggered; and
third mapping means, for mapping the SRS request field in the uplink grant according
to the pre-assigned corresponding relationship to mark the value of a bit corresponding to the
determined UL CC as "trigger".
According to another embodiment of the present invention, there is provided a
transmission apparatus of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
fourth pre-assigning means, for pre-assigning a corresponding relationship between bits
of the SRS request field in an uplink grant and multiple uplink component carriers UL CCs of
user equipment, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system; and
fourth determining means, for demapping, according to the pre-assigned corresponding
relationship, the SRS request field in the received uplink grant so as to determine the UL CC
for which SRS transmission will be implemented.
According to another embodiment of the present invention, there is provided a
triggering method of aperiodic channel state information CSI for a carrier aggregation system,
comprising:
(1) pre-assigning a mapping relationship between different values of the CSI request
field in an uplink grant and CSI requests for different combinations of downlink component
carriers DL CCs, wherein the number of bits of the CSI request field is greater than 1 and lessthan the maximum allowed number of DL CCs in the system;
(2) determining the DL CC for which aperiodic CSI reporting is to be triggered; and
(3) populating values of the CSI request field in the uplink grant according to the
pre-assigned mapping relationship and the determined DL CC.
According to another embodiment of the present invention, there is provided a
reporting method of aperiodic channel state information CSI for a carrier aggregation system,
comprising:
(1) pre-assigning a mapping relationship between different values of the CSI request
field in an uplink grant and CSI requests for different combinations of downlink component
carriers DL CCs, wherein the number of bits of the CSI request field is greater than 1 and less
than the maximum allowed number of DL CCs in the system; and
(2) demapping, according to the pre-assigned mapping relationship, the CSI request
field in the received uplink grant so as to determine a DL CC for which aperiodic CSI
reporting is to be implemented.
According to another embodiment of the present invention, there is provided a
triggering apparatus of aperiodic channel state information CSI for a carrier aggregation
system, comprising:
(1) fifth pre-assigning means, for pre-assigning a mapping relationship between
different values of the CSI request field in an uplink grant and CSI requests for different
combinations of downlink component carriers DL CCs, wherein the number of bits of the CSI
request field is greater than 1 and less than the maximum allowed number of DL CCs in the
system;
(2) fifth determining means, for determining the DL CC for which aperiodic CSI
reporting is to be triggered; and
(3) fifth mapping means, for populating values of the CSI request field in the uplink
grant according to the pre-assigned mapping relationship and the determined DL CC.
According to another embodiment of the present invention, there is provided a
reporting apparatus of aperiodic channel state information CSI for a carrier aggregation
system, comprising:
(1) sixth pre-assigning means, for pre-assigning a mapping relationship between
different values of the CSI request field in an uplink grant and CSI requests for differentcombinations of downlink component carriers DL CCs, wherein the number of bits of the CSI
request field is greater than 1 and less than the maximum allowed number of DL CCs in the
system; and
(2) sixth determining means, for demapping, according to the pre-assigned mapping
relationship, the CSI request field in the received uplink grant so as to determine a DL CC for
which aperiodic CSI reporting is to be implemented.
According to another embodiment of the present invention, there is provided a
triggering method of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) pre-assigning a mapping relationship between different bits of the SRS request field
in an uplink grant and SRS requests for different combinations of uplink component carriers
UL CCs, wherein the number of bits of the SRS request field is greater than 1 and less than
the maximum allowed number of UL CCs in the system;
(2) determining the UL CC for which aperiodic SRS is to be triggered; and
(3) populating values of the SRS request field in the uplink grant according to the
pre-assigned mapping relationship and the determined UL CC.
According to another embodiment of the present invention, there is provided a
transmission method of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) pre-assigning a mapping relationship between different bits of the SRS request field
in an uplink grant and SRS requests for different combinations of uplink component carriers
UL CCs, wherein the number of bits of the SRS request field is greater than 1 and less than
the maximum allowed number of UL CCs in the system; and
(2) demapping, according to the pre-assigned mapping relationship, the SRS request
field in the received uplink grant so as to determine a UL CC on which SRS transmission is to
be implemented.
According to another embodiment of the present invention, there is provided a
triggering apparatus of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) seventh pre-assigning means, for pre-assigning a mapping relationship between
different bits of the SRS request field in an uplink grant and SRS requests for differentcombinations of uplink component carriers UL CCs, wherein the number of bits of the SRS
request field is greater than 1 and less than the maximum allowed number of UL CCs in the
system;
(2) seventh determining means, for determining the UL CC for which aperiodic SRS is
to be triggered; and
(3) seventh mapping means, for populating values of the SRS request field in the uplink
grant according to the pre-assigned mapping relationship and the determined UL CC.
According to another embodiment of the present invention, there is provided a
transmission apparatus of an aperiodic uplink sounding reference signal SRS for a carrier
aggregation system, comprising:
(1) eighth pre-assigning means, for pre-assigning a mapping relationship between
different bits of the SRS request field in an uplink grant and SRS requests for different
combinations of uplink component carriers UL CCs, wherein the number of bits of the SRS
request field is greater than 1 and less than the maximum allowed number of UL CCs in the
system; and
(2) eighth determining means, for demapping, according to the pre-assigned mapping
relationship, the SRS request field in the received uplink grant so as to determine a UL CC on
which SRS transmission is to be implemented.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features, objects, and advantages of the present invention will become more
apparent from the detailed description of the non-limiting embodiments, when taken in
conjunction with the figures wherein,
Fig. 1 illustrates a schematic view of DL/UL pair and cross-carrier scheduling in an
LTE-Advanced system;
Fig. 2 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention;
Fig. 3 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of thepresent invention;
Fig. 4 illustrates a flowchart of a reporting method of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention;
Fig. 5 illustrates a block diagram of a triggering apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention;
Fig. 6 illustrates a block diagram of a reporting apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention;
Fig. 7 illustrates a flowchart of a triggering method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to an embodiment of the
present invention;
Fig. 8 illustrates a flowchart of a transmission method of aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to an embodiment of the
present invention;
Fig. 9 illustrates a block diagram of a triggering apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to an embodiment
of the present invention;
Fig. 10 illustrates a block diagram of a transmission apparatus of aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to an embodiment
of the present invention;
Fig. 11 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention;
Fig. 12 illustrates a flowchart of a reporting method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention;
Fig. 13 illustrates a block diagram of a triggering apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention;Fig. 14 illustrates a block diagram of a reporting apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention;
Fig. 15 illustrates a flowchart of a triggering method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to another embodiment of the
present invention;
Fig. 16 illustrates a flowchart of a transmission method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to another embodiment of the
present invention;
Fig. 17 illustrates a block diagram of a triggering apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to another
embodiment of the present invention; and
Fig. 18 illustrates a block diagram of a transmission apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to another
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Methods and apparatuses for processing aperiodic channel state information
transmission for a carrier aggregation system will be described below with reference to the
specific embodiments and in conjunction with the figures. The aperiodic information
transmission comprises, for example, aperiodic CSI reporting or aperiodic SRS transmission.
According to the embodiments of the present invention, there are provided methods
and apparatuses for triggering aperiodic CSI reporting and aperiodic SRS transmission on
PUSCH for carrier aggregation.
Aperiodic CSI request
In the embodiments of the present invention, there is provided an efficient mechanism
to trigger aperiodic CSI reporting for configurable multiple DL CCs (N, for example, N being
a positive integer equal to or greater than 1) by limited bit-mapping bits, where N is equal to
or less than the number of configured or activated CCs for UE, so as to achieve a
tradeoff between DCI format size and UL grant overhead. In systems where someembodiments are applied, only requesting or triggering of CSI reporting for activated DL CCs
might be allowed; hence, only activated CCs of UE are considered in such embodiments. In
systems where other embodiments are applied, only triggering of CSI reporting for
deactivated DL CCs might be allowed; hence, configured CCs of UE should be considered in
those embodiments.
As known from RAN2, up to 5 CCs may be configured for each cell, and each UL CC
is always paired with one DL CC to compose a cell, within which UL grants and DL
assignments are always scheduled from the same cell, as illustrated in Fig. 1. Based on this
agreement, several ways of triggering aperiodic CSI reporting for multiple configurable DL
CCs are proposed in the embodiments of the present invention.
Altl: Bit mapping with 5-bit in all UL grants to trigger aperiodic CSI reporting for up
to 5 configurable DL CCs. If the number of activated DL CCs for the specific UE is less
than 5, some bits in the 5-bit field of aperiodic CSI request are reserved. Although these
reserved bits are unnecessary to be decoded correctly in this case, the 5-bit field of aperiodic
CSI request is always configured for all UL grants, which increases the size of all DCI
formats for UL grant.
Even though 5-bit aperiodic CSI requests are configured for all UL grants, another
issue is raised whether to overlap the aperiodic CSI request field or not for multiple UL grants
when multiple UL grants are sent in one subframe (or TTI) by eNB (including the eNB
configuration and the UE corresponding behavior). To avoid confusion, it is proposed to
specify two different ways as follows.
a) Specify that the UE should follow the aperiodic CSI request in one UL grant and
ignore the aperiodic CSI request in other UE grants in line with the principle of uplink control
information (UCI) multiplexing on PUSCH for carrier aggregation.
In the case that there is a PUSCH (uplink shared channel) transmission with data on the
prime component carrier (PCC), the UE follow the aperiodic CSI request in the UL grant
provided for PCC to trigger the aperiodic CSI reporting and ignore the aperiodic CSI request
in other UE grants.
In the case that there is one or more PUSCH transmissions with data and no PUSCH
transmission with data on PCC, the UE follow the aperiodic CSI request in the UL grant
provided for SCC to trigger the aperiodic CSI reporting and ignore the aperiodic CSI request
in other UE grants. If there are multiple SCCs, it is possible to pre-specify which SCC to beselected by higher layer signalling or specify a priority order for selection.
b) Specify that the aperiodic CSI request field in the uplink grant is 5-bits. The eNB
configures the same content for the 5-bit aperiodic CSI request in all UL grants, and the UE
follows the aperiodic CSI request that most CCs have the same indication. For example, for
∑ b ≥
each CC, the aperiodic CSI reporting for the CC is triggered if
_1
, otherwise not
triggered, where is the triggering value of each CC ( '
~ ' 0 denotes not trigger, and 1
denotes trigger). Specifically, assuming 3 UL grants are sent in one subframe and for CC1,
only one uplink grant indicates trigger and the other two do not indicate trigger, i.e.,
bi - 'b2 - 'b3
_
e
aperiodic CSI reporting for DL CC1 is not triggered.
Alt2: The aperiodic CSI request field in the uplink grant is 1-bit. eNB keeps the
1-bit aperiodic CSI request in all UL grants and sends a UL grant for each DL CC which
needs to trigger aperiodic CSI reporting. If multiple DL CCs need to trigger aperiodic CSI
reporting, multiple uplink grants are then needed to be sent accoridng to this mehtod.
Therefore, UL grant overhead is significantly increased, although every DCI format of the UL
grants has the minimum size.
Alt3: The aperiodic CSI request field in the uplink grant has a limited number of bits,
where the number of bits is greater than 1 and less than the allowed number of CCs in the
system. Bit mapping with limited bits in all UL grants are used to trigger aperiodic CSI
reporting for the requisite DL CCs such as,
the DL CC with which no UL CC is paired (e.g., CC3 in Fig. 1), and
the DL CC with which a UL CC is paired, wherein the paired UL CC has no UL-SCH
data transmissions (e.g., CC2 in Fig. 1).
The DL CC whose paired UL CC has UL-SCH data transmission (e.g., CC1 in Fig. 1)
does not belong to the above requisite DL CCs. Since the UL grant is required to schedule
UL data transmission in this case, using the aperiodic CSI request in its UL grant does not
increase UL grant overhead.
In reality, it seldom happens that all 5 DL CCs are configured or activated for the
specific UE and simultaneously all the configured or activated DL CCs operate like CC2
(whose paired UL CC has no UL-SCH data transmission) or CC3 (which has no paired UL
CC). Therefore, using bit mapping with 3 bits to trigger aperiodic CSI reporting may besufficient in most scenarios. In case that 3 bits are not enough in the worst scenario, several
solutions could be used to address as complementarities.
For example, in addition to sending an uplink grant with UL-SCH data transmission
(referred to as a first uplink grant), remaining DL CCs that are not triggered by the first uplink
grant are triggered by using one or more further DL CCs. For example, single-bit triggering
uplink grants as many as remaining DL CCs may be used (i.e., uplink grants that only trigger
CCs marked with CIF). Uplink grants without UL-SCH data transmission may be
transmitted in the same TTI as uplink grants with UL-SCH data transmission or transmitted in
a subsequent TTI.
The application of these complementary solutions varies depending on different
application environments. In most cases, only one uplink grant needs to be sent, so uplink
grant overhead is relatively small. Furthermore, the CSI request field with a limited number
of bits makes the DCI format relatively small. Thus, Alt3 achieves a trade-off between DCI
format size and UL grant overhead, which is a preferred implementation solution.
Alt4: The aperiodic CSI request field in the uplink grant has a limited number of bits,
wherein the number of bits is greater than 1 and less than the allowed number of CCs in the
system. Bit mapping with limited bits in all UL grants is used to trigger aperiodic CSI
reporting for a configurable number of DL CCs, and each bit is used to trigger aperiodic CSI
reporting for a subset of up to DL CCs. For example, in the case that the system allows 5
CCs at most (e.g., CC1, CC2, CC3, CC4, and CC5), CC1 and CC2 are grouped into a subset,
CC3 and CC4 are grouped into another subset, and CC5 is a subset. Those skilled in the art
would appreciate that the CC grouping may have various ways. For example, each of CC1
and CC2 is a subset, while CC3-CC5 are grouped into a subset, etc. The CC grouping may
be pre-assigned and semi-statically configured by higher layer signalling. Each bit in the
limited bit-mapping of UL grant can trigger aperiodic CSI reporting for a subset of DL CCs.
Thus the DCI format size is saved. Although additional CSI reporting overhead is incurred
when not all CCs in the subset of CCs are triggered for aperiodic CSI reporting, this solution
is still superior to using one uplink grant to trigger aperiodic CSI reporting for all DL CCs.
Alt5: The aperiodic CSI request field in the uplink grant has a limited number of bits,
wherein the number of bits is greater than 1 and less than the allowed number of CCs in the
system. The limited bits in the CSI request field may have different combination values, i.e.,
this CSI request field may have different values. It is possible to indicate CSI requests for
different combinations of DL CCs by these different values. Mapping relationships betweendifferent values of the CSI request field and CSI requests for different combinations (subsets)
of DL CCs may be pre-assigned by higher layer signalling (e.g., RRC signalling). As
described above, component carriers here may only consider activated CCs of UE or
configured CCs of UE.
In one embodiment, the aperiodic CSI request field in a uplink grant has 2 bits, and UE
has 3 activated (or configured) DL CCs, marked as CC1, CC2, and CC3, respectively. The
CSI request field may have 4 different values, i.e., 00, 01, 10, and 11. It is possible to
preassign mapping relationships between different values of the CSI request field and
different CC combinations by higher layer signalling. For example, one CSI request value
(e.g., 10) indicates triggering CSI reporting for only the DL CC that carries this uplink grant.
A different value (e.g., 11) indicate triggering CSI reporting for all DL CCs. The other two
values may indicate CSI reporting for the other two different combinations of DL CCs, for
exampple, 00 indicates triggering no CSI reporting for any DL CC, and 01 indicates triggering
CSI reporting for CC1 and CC2.
In another embodiment, the aperiodic CSI request field in uplink grant has 3 bits. The
CSI request field may have 9 different values, i.e., 000, 001, . . . , 111. Hence, it is possible
to express CSI requests for a maximum of 9 different combinations of DL CCs. Below is
presented an example of mapping relationships between values of the CSI request field and
activated DL CCs in the case that UE has 4 CCs.
000 -trigger no CSI reporting for any DL CC;
100 - trigger reporting for the DL CC (e.g., CC1) that carries the uplink grant;
001 - trigger CSI reporting for CC1 & CC2;
010 - trigger CSI reporting for CC2 & CC3;
111- trigger CSI reporting for all DL CCs.
Aperiodic SRS request
In another embodiment of the present invention, there is provided an efficient
mechanism to trigger aperiodic SRS transmission for multiple configurable UL CCs (e.g., an
N number of UL CCs, wherein N is a positive integer equal to or greater than 1) by limited
bit-mapping bits, where N is equal to or less than the number of configured or activatedCCs for UE, so as to achieve a tradeoff between DCI format size and UL grant overhead. In
systems where some embodiments are applied, only requesting or triggering of CSI reporting
for activated DL CCs might be allowed; hence, only activated CCs of UE are considered in
such embodiments. In systems where other embodiments are applied, only triggering of CSI
reporting for deactivated DL CCs might be allowed; hence, configured CCs of UE should be
considered in those embodiments.
Triggering aperiodic SRS transmission for multiple CCs may employ the similar
methods investigated for triggering aperiodic CSI reporting. That is, the above Altl, Alt2,
Alt3, Alt4, and Alt5 for CSI request may be used to SRS request through simple modifications.
The only difference is that since CSI is channel quality feedback for DL CCs and SRS is
reference signal transmission for UL CCs, bits in the CSI request field in uplink grant are
mapped to the DL CC, while bits in the SRS request field in uplink grant are mapped to the
UL CC.
Detailed description is presented below with with reference to the figures.
Fig. 1 illustrates a schematic view of DL/UL pair and cross-carrier scheduling in an
LTE-Advanced system.
In the system, there are configured 3 DL CCs, namely CCl, CC2, and CC3, together
with 2 UL CCs, namely CCl' and CC2\ CCl and CCl' form a cell, and on CCl' there is
data transmission to be scheduled; CC2 and CC2' form a cell. CC3 has no UL CC with
which it is paired. In this case, cross scheduling is enabled.
Since on CCl' there is data transmission to be scheduled, eNB will send an uplink
scheduling for data transmission on CCl'. According to the embodiments of the present
invention, eNB may simultaneously trigger CSI reporting for CCl, CC2 and/or CC3 by
mapping the CSI request field in the uplink scheduling. Further, eNB may simultaneously
trigger SRS transmission for CCl' and CC2' by mapping the SRS request field in the uplink
scheduling.
Illustration is presented below to processing of the CSI request field in the
embodiments of the present invention by taking Alt3 for example. In one embodiment, it
may be pre-specified that the CSI request field is 3-bit. One bit of the 3-bit CSI (e.g., the
first bit) request field is assigned to the CC that is indicated in the CIF field, and the other two
bits are mapped according to a priority order of DL CCs. If the high-to-low priority order of
DL CCs is CCl, CC3, and CC2, in the case as illustrated in Fig. 1, the first bit of the CSIrequest field is mapped to CC1, the second bit to CC3, and the third bit to CC2. In one
embodiment, the last bit (e.g., the third bit) of the 3-bit CSI request field may be assigned to
the CC that is indicated in the CIF field, and the other two bits are assigned to the other two
CCs in the CC sequential order given by upper layer signalling. In the case as illustrated in
Fig. 1, the first bit of the CSI request field is mapped to CC2, the second bit to CC3, and the
third bit to CCl.
Illustration is then presented below to processing of the SRS request field in the
embodiments of the present invention by taking Alt3 for example. In one embodiment, it
may be pre-specified that the SRS request field is 3-bit. Due to the moment of time in Fig. 1,
only 2 UL CCs are configured for the UE, so one bit may be reserved. It may be specified
by higher layer signalling that pne bit of the 3-bit SRS request field (e.g., the first bit) is to be
assigned to the CC that is indicated in the CIF field, the middle bit is assigned to the other UL
CC, and the last bit is used as a reserved bit.
Those skilled in the art would appreciate that if more UL CCs are configured or
activated for the UE, it is then possible to correspond one bit of the SRS request field in
uplink grant to the DL CC that is carrying the uplink grant, and to correspond the remaining
bits to different UL CCs according to a priority order of UL CCs or CC serial numbers given
by upper layer signalling.
Fig. 2 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention. As illustrated in Fig. 2, a corresponding relationship between bits of the CSI
request field in uplink grant and multiple downlink component carriers DL CCs is
pre-assigned in step 201, wherein the number of bits of the CSI request field is greater than 1
and less than the maximum allowed number of DL CCs in the system. In step 202, the DL
CC for which aperiodic CSI reporting is to be triggered is determined. In step 203, the CSI
request field in uplink grant is mapped according to the pre-assigned corresponding
relationship, marking the value of the bit corresponding to the determined DL CC as "trigger".
According to one embodiment of the present invention, step 201 further comprises
dividing all DL CCs for the user equipment UE into multiple subsets and corresponding
different bits of the CSI request field to different subsets.
According to one embodiment of the present invention, step 203 further comprises
marking the value of the bit corresponding to the subset to which the DL CC determined instep 202 belongs as "trigger".
According to one embodiment of the present invention, the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
According to one embodiment of the present invention, step 201 further comprises
corresponding one bit of the CSI request field in uplink grant to the DL CC that is carrying the
uplink grant, and corresponding the remaining bits to different DL CCs according to a priority
order of DL CCs or CC serial numbers given by upper layer signaling.
According to one embodiment of the present invention, step 203 further comprises
marking the value of the bit corresponding to the DL CC determined in step 202 as "trigger"
during mapping of the CSI request field.
According to one embodiment of the present invention, DL CCs corresponding to the
remaining bits do not include a DL CC that has an associated uplink component carrier UL
CC on which there is data transmission on the uplink shared channel UL SCH.
Fig. 3 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention. The embodiment as illustrated in Fig. 3 not only includes steps 202-203
but also includes step 304. In step 304, when one uplink grant is not sufficient to trigger CSI
reporting for all DL CCs determined in step 202, multiple single-bit triggering uplink grants
are sent in the same subframe as the first uplink grant or in a subsequent subframe.
Fig. 4 illustrates a flowchart of a reporting method of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention. As illustrated in Fig. 4, in step 401, a corresponding relationship between bits of
the CSI request field in uplink grant and multiple downlink component carriers DL CCs of the
user equipment is pre-assigned, wherein the number of bits of the CSI request field is greater
than 1 and less than the maximum allowed number of DL CCs in the system. In step 402,
the CSI request field in the received uplink grant is demapped according to the pre-assigned
corresponding relationship, so as to determine a DL CC for which aperiodic CSI reporting
will be implemented.
According to one embodiment of the present invention, step 401 further comprises
dividing all DL CCs for the user equipment UE into multiple subsets and corresponding
different bits of the CSI request field to different subsets. According to one embodiment ofthe present invention, step 402 further comprises determining that aperiodic CSI reporting is
to be implemented for all DL CCs in the subset corresponding to the bit that is marked as
"trigger" in the CSI request field.
According to one embodiment of the present invention, the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
According to one embodiment of the present invention, step 401 further comprises
corresponding one bit of the CSI request field in uplink grant to the DL CC that is carrying the
uplink grant, and corresponding the remaining bits to different DL CCs according to a priority
order of DL CCs or CC serial numbers given by upper layer signaling.
According to one embodiment of the present invention, step 402 further comprises
determining that aperiodic CSI reporting is to be implemented for the DL CC corresponding
to the bit that is marked as "trigger" in the CSI request field.
According to one embodiment of the present invention, DL CCs corresponding to the
remaining bits do not include a DL CC that has an associated uplink component carrier UL
CC on which there is data transmission on the uplink shared channel UL SCH.
Fig. 5 illustrates a block diagram of a triggering apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention. The triggering apparatus as illustrated in Fig. 5 comprises first pre-assigning
means 501, first determining means 502, and mapping means 503. The first pre-assigning
means is for pre-assigning a corresponding relationship between bits of the CSI request field
in uplink grant and multiple downlink component carriers DL CCs of user equipment,
wherein the number of bits of the CSI request field is greater than 1 and less than the
maximum allowed number of DL CCs in the system. The first determining means 502 is for
determining the DL CC for which aperiodic CSI reporting is to be triggered. The mapping
means 503 is for mapping the CSI request field in uplink grant according to the pre-assigned
corresponding relationship, marking the value of the bit corresponding to the determined DL
CC as "trigger".
According to one embodiment of the present invention, the first pre-assigning means
501 is further for dividing all DL CCs for the user equipment UE into multiple subsets and
corresponding different bits of the CSI request field to different subsets.
According to one embodiment of the present invention, the mapping means 503 isfurther for marking the value of the bit corresponding to the subset to which the DL CC
determined in step 202 belongs as "trigger".
According to one embodiment of the present invention, the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
According to one embodiment of the present invention, the first pre-assigning means
501 is further for corresponding one bit of the CSI request field in uplink grant to the DL CC
that is carrying the uplink grant, and corresponding the remaining bits to different DL CCs
according to a priority order of DL CCs or CC serial numbers given by upper layer signaling.
According to one embodiment of the present invention, the mapping means 503 is
further for marking the value of the bit corresponding to the DL CC determined by the first
determining means 502 as "trigger" during mapping of the CSI request field.
According to one embodiment of the present invention, DL CCs corresponding to the
remaining bits do not include a DL CC that has an associated uplink component carrier UL
CC on which there is data transmission on the uplink shared channel UL SCH.
Fig. 6 illustrates a block diagram of a reporting apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to an embodiment of the present
invention. The reporting apparatus 600 as illustrated in Fig. 6 comprises second
pre-assigning means 601 and second determining means 602. The second pre-assigning
means 601 is for pre-assigning a corresponding relationship between bits of the CSI request
field in uplink grant and multiple downlink component carriers DL CCs of the user
pre-assigned, wherein the number of bits of the CSI request field is greater than 1 and less
than the maximum allowed number of DL CCs in the system. The second determining
means 602 is for demapping, according to the pre-assigned corresponding relationship, the
CSI request field in the received uplink grant so as to determine a DL CC for which aperiodic
CSI reporting will be implemented.
According to one embodiment of the present invention, the second pre-assigning means
601 is further for dividing all DL CCs for the user equipment UE into multiple subsets and
corresponding different bits of the CSI request field to different subsets.
According to one embodiment of the present invention, the second determining means
602 is further for determining that aperiodic CSI reporting is to be implemented for all DL
CCs in the subset corresponding to the bit that is marked as "trigger" in the CSI request field.According to one embodiment of the present invention, the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
According to one embodiment of the present invention, the second pre-assigning means
is further for corresponding one bit of the CSI request field in uplink grant to the DL CC that
is carrying the uplink grant, and corresponding the remaining bits to different DL CCs
according to a priority order of DL CCs or CC serial numbers given by upper layer signaling.
According to one embodiment of the present invention, the second determining means
602 is further for determining that aperiodic CSI reporting is to be implemented for the DL
CC corresponding to the bit that is marked as "trigger" in the CSI request field.
According to one embodiment of the present invention, DL CCs corresponding to the
remaining bits do not include a DL CC that has an associated uplink component carrier UL
CC on which there is data transmission on the uplink shared channel UL SCH.
Fig. 7 illustrates a flowchart of a triggering method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to an embodiment of the
present invention. As illustrated in Fig. 7, a corresponding relationship between bits of the
SRS request field in uplink grant and multiple uplink component carriers UL CCs is
pre-assigned in step 701, wherein the number of bits of the SRS request field is greater than 1
and less than the maximum allowed number of UL CCs in the system. In step 702, the UL
CC for which aperiodic SRS is to be triggered is determined. In step 703, the SRS request
field in uplink grant is mapped according to the pre-assigned corresponding relationship,
marking the value of the bit corresponding to the determined UL CC as "trigger".
According to one embodiment of the present invention, step 701 further comprises
dividing all UL CCs for the user equipment UE into multiple subsets and corresponding
different bits of the SRS request field to different subsets.
According to one embodiment of the present invention, step 703 further comprises
marking the value of the bit corresponding to the subset to which the UL CC determined in
step 702 belongs as "trigger".
According to one embodiment of the present invention, step 701 further comprises
corresponding one bit of the SRS request field in uplink grant to the CC that is specified by
the CIF field in the same uplink grant, and corresponding the remaining bits to different UL
CCs according to a priority order of UL CCs or CC serial numbers given by upper layersignaling. Those skilled in the art would appreciate that the CC specified by the CIF field in
the same uplink grant is the carrier paired with the DL CC that is carrying the uplink grant.
According to one embodiment of the present invention, step 703 further comprises
marking the value of the bit corresponding to the UL CC determined in step 702 as "trigger"
during mapping of the SRS request field.
Fig. 8 illustrates a flowchart of a transmission method of aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to an embodiment of the
present invention. As illustrated in Fig. 8, in step 801, a corresponding relationship between
bits of the SRS request field in uplink grant and multiple uplink component carriers UL CCs
of the user equipment is pre-assigned, wherein the number of bits of the SRS request field is
greater than 1 and less than the maximum allowed number of UL CCs in the system. In step
802, the SRS request field in the received uplink grant is demapped according to the
pre-assigned corresponding relationship, so as to determine the UL CC for which SRS
transmission will be implemented.
According to one embodiment of the present invention, step 801 further comprises
dividing all UL CCs for the user equipment UE into multiple subsets and ccorresponding
different bits of the SRS request field to different subsets.
According to one embodiment of the present invention, step 802 further comprises
determining that SRS transmission is to be implemented on all UL CCs in the subset
corresponding to the bit that is marked as "trigger" in the SRS request field.
According to one embodiment of the present invention, step 801 further comprises
corresponding one bit of the SRS request field in uplink grant to the CC that is specified by
the CIF field in the same uplink grant, and corresponding the remaining bits to different UL
CCs according to a priority order of UL CCs or CC serial numbers given by upper layer
signaling.
According to one embodiment of the present invention, step 802 further comprises
determining that SRS transmission is to be implemented on the UL CC corresponding to the
bit that is marked as "trigger" in the SRS request field.
Fig. 9 illustrates a block diagram of a triggering apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to an embodiment
of the present invention. The triggering apparatus as illustrated in Fig. 9 comprises third
pre-assigning means 901, third determining means 902, and third mapping means 903. Thethird pre-assigning means 901 is for pre-assigning a corresponding relationship between bits
of the SRS request field in uplink grant and multiple uplink component carriers UL CCs of
user equipment wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system. The third determining means
902 is for determining the UL CC for which aperiodic SRS is to be triggered. The third
mapping means 903 is for mapping the SRS request field in uplink grant according to the
pre-assigned corresponding relationship, marking the value of the bit corresponding to the
determined UL CC as "trigger".
According to one embodiment of the present invention, the third pre-assigning means
901 further divides all UL CCs for the user equipment UE into multiple subsets and
corresponds different bits of the SRS request field to different subsets.
According to one embodiment of the present invention, the third mapping means 903
further marks the value of the bit corresponding to the subset to which the UL CC determined
by the third determining means 902 belongs as "trigger".
According to one embodiment of the present invention, the third pre-assigning means
901 further corresponds one bit of the SRS request field in uplink grant to the CC that is
specified by the CIF field in the same uplink grant, and corresponds the remaining bits to
different UL CCs according to a priority order of UL CCs or CC serial numbers given by
upper layer signaling.
According to one embodiment of the present invention, the third mapping means 903
further marks the value of the bit corresponding to the UL CC determined by the third
determining means 902 as "trigger" during mapping of the SRS request field.
Fig. 10 illustrates a block diagram of a transmission apparatus of aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to an embodiment
of the present invention. The transmission apparatus as illustrated in Fig. 10 comprises
fourth pre-assigning means 1001 and fourth determining means 1002. The fourth
pre-assigning means 1001 is for pre-assigning a corresponding relationship between bits of
the SRS request field in uplink grant and multiple uplink component carriers UL CCs of the
user equipment, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system. The fourth determining means
1002 is for demapping, according to the pre-assigned corresponding relationship, the SRS
request field in the received uplink grant so as to determine the UL CC for which SRStransmission will be implemented.
According to one embodiment of the present invention, the fourth pre-assigning means
further divides all UL CCs for the user equipment UE into multiple subsets and corresponds
different bits of the SRS request field to different subsets.
According to one embodiment of the present invention, the fourth determining means
1002 further determines that SRS transmission is to be implemented on all UL CCs in the
subset corresponding to the bit that is marked as "trigger" in the SRS request field.
According to one embodiment of the present invention, the fourth pre-assigning means
1001 further corresponds one bit of the SRS request field in uplink grant to the CC that is
specified by the CIF field in the same uplink grant, and corresponds the remaining bits to
different UL CCs according to a priority order of UL CCs or CC serial numbers given by
upper layer signaling.
According to one embodiment of the present invention, the fourth determining means
1002 further determines that SRS transmission is to be implemented on the UL CC
corresponding to the bit that is marked as "trigger" in the SRS request field.
Fig. 11 illustrates a flowchart of a triggering method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention. As illustrated in Fig. 11, a mapping relationship between different values
of the CSI request field in uplink grant and CSI requests for different combinations of
downlink component carriers DL CCs is pre-assigned in step 1101, wherein the number of
bits of the CSI request field is greater than 1 and less than the maximum allowed number of
DL CCs in the system. In step 1102, the DL CC for which aperiodic CSI reporting is to be
triggered is determined. In step 1103, values of the CSI request field in a uplink grant is
populated according to the pre-assigned mapping relationship and the determined DL CC.
According to one embodiment of the present invention, the mapping relationship
comprises: mapping a first value of the CSI request field to indicate that CSI reporting for the
DL CC carrying the uplink grant is to be triggered, mapping a second value of the CSI request
field to indicate that CSI reporting for all DL CCs is to be triggered, and mapping other values
to indicate that CSI reporting for other different combinations of DL CCs is to be triggered.
Fig. 12 illustrates a flowchart of a reporting method of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention. As illustrated in Fig. 12, a mapping relationship between different valuesof the CSI request field in uplink grant and CSI requests for different combinations of
downlink component carriers DL CCs is pre-assigned in step 1201, wherein the number of
bits of the CSI request field is greater than 1 and less than the maximum allowed number of
DL CCs in the system. In step 1202, the CSI request field in the received uplink grant is
demapped according to the pre-assigned mapping relationship, so as to determine the DL CC
for which aperiodic CSI reporting is to be implemented.
Fig. 13 illustrates a block diagram of a triggering apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention. The triggering apparatus 1300 as illustrated in Fig. 13 comprises fifth
pre-assigning means 1301, fifth determining means 1302, and fifth mapping means 1303.
The fifth pre-assigning means 1301 is for pre-assigning a mapping relationship between
different values of the CSI request field in uplink grant and CSI requests for different
combinations of downlink component carriers DL CCs, wherein the number of bits of the CSI
request field is greater than 1 and less than the maximum allowed number of DL CCs in the
system. The fifth determining means 1302 is for determining the DL CC for which aperiodic
CSI reporting is to be triggered. The fifth mapping means 1303 is for populating value of
the CSI request field in uplink grant according to the pre-assigned mapping relationship and
the determined DL CC.
Fig. 14 illustrates a block diagram of a reporting apparatus of aperiodic channel state
information CSI for a carrier aggregation system according to another embodiment of the
present invention. The reporting apparatus 1400 as illustrated in Fig. 14 comprises sixth
pre-assigning means 1401 and sixth determining means 1402. The sixth pre-assigning
means 1401 is for pre-assigning a mapping relationship between different values of the CSI
request field in uplink grant and CSI requests for different combinations of downlink
component carriers DL CCs, wherein the number of bits of the CSI request field is greater
than 1 and less than the maximum allowed number of DL CCs in the system. The sixth
determining means 1402 is for demapping, according to the pre-assigned mapping
relationship, the CSI request field in the received uplink grant so as to determine the DL CC
for which aperiodic CSI reporting is to be implemented.
Fig. 15 illustrates a flowchart of a triggering method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to another embodiment of the
present invention. As illustrated in Fig. 15, a mapping relationship between different bits of
the SRS request field in uplink grant and SRS requests for different combinations of uplinkcomponent carriers UL CCs is pre-assigned in step 1501, wherein the number of bits of the
SRS request field is greater than 1 and less than the maximum allowed number of UL CCs in
the system. In step 1502, the UL CC for which aperiodic SRS is to be triggered is
determined. In step 1503, values are populated into the SRS request field in uplink grant
according to the pre-assigned mapping relationship and the determined UL CC.
According to one embodiment of the present invention, the mapping relationship
comprises: mapping a first value of the SRS request field to indicate that SRS transmission on
the CC specified by the carrier indicator field in uplink grant is to be triggered, and mapping a
second value of the SRS request field to indicate that SRS transmission on all UL CCs is to be
triggered.
Fig. 16 illustrates a flowchart of a transmission method of an aperiodic uplink sounding
reference signal SRS for a carrier aggregation system according to another embodiment of the
present invention. As illustrated in Fig. 16, a mapping relationship between different bits of
the SRS request field in uplink grant and SRS requests for different combinations of uplink
component carriers UL CCs is pre-assigned in step 1601, wherein the number of bits of the
SRS request field is greater than 1 and less than the maximum allowed number of UL CCs in
the system. In step 1602, the SRS request field in the received uplink grant is demapped
according to the pre-assigned mapping relationship, so as to determine a UL CC on which
SRS transmission is to be implemented.
Fig. 17 illustrates a block diagram of a triggering apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to another
embodiment of the present invention. The triggering apparatus 1700 as illustrated in Fig. 17
comprises seventh pre-assigning means 1701, seventh determining means 1702, and seventh
mapping means 1703. The seventh pre-assigning means 1701 is for pre-assigning a mapping
relationship between different bits of the SRS request field in uplink grant and SRS requests
for different combinations of uplink component carriers UL CCs, wherein the number of bits
of the SRS request field is greater than 1 and less than the maximum allowed number of UL
CCs in the system. The seventh determining means 1702 is for determining the UL CC for
which aperiodic SRS is to be triggered. The seventh mapping means 1703 is for populating
values of the SRS request field in uplink grant according to the pre-assigned mapping
relationship and the determined UL CC.
Fig. 18 illustrates a block diagram of a transmission apparatus of an aperiodic uplink
sounding reference signal SRS for a carrier aggregation system according to anotherembodiment of the present invention. The apparatus as illustrated in Fig. 18 comprises
eighth pre-assigning means 1801 and eighth determining means 1802. The eighth
pre-assigning means 1801 is for pre-assigning a mapping relationship between different bits
of the SRS request field in uplink grant and SRS requests for different combinations of uplink
component carriers UL CCs, wherein the number of bits of the SRS request field is greater
than 1 and less than the maximum allowed number of UL CCs in the system. The eighth
determining means 1802 is for demapping, according to the pre-assigned mapping
relationship, the SRS request field in the received uplink grant so as to determine a UL CC on
which SRS transmission is to be implemented.
The embodiments of the present invention provide a mechanism to trigger aperiodic
CSI/SRS for a configurable number of DL CCs for carrier aggregation. The mechanism uses
a limited number of bits as the CSI/SRS request field and indicates aperiodic CSI/SRS
requests for different combinations of DL CCs through bit mapping or multi-bit value
mapping. As such, the mechanism not only can be configured flexibly but also minimizes
additional overhead for uplink grant, thereby achieving a tradeoff between DCL format size
and UL grant overhead. Compared with the existing solutions, the present invention
increases no feedback delay and achieves a tradeoff between DCI format size and UL grant
overhead by triggering aperiodic CSI/SRS for multiple DL CCs in one subset.
Therefore, the solution of triggering aperiodic CSI reporting for configurable DL CCs
achieves reduced CSI reporting delay and tolerable CSI reporting overhead.
The embodiments of the present invention have been described above. However, the
present invention is not limited to the specific methods and apparatuses. On the contrary,
those skilled in the art may make various variations or modifications within the scope of the
appended claims.WHAT IS CLAIMED IS:
1. A triggering method of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the CSI request field in
an uplink grant and multiple downlink component carriers DL CCs of user equipment,
wherein the number of bits of the CSI request field is greater than 1 and less than the
maximum allowed number of DL CCs in the system;
(2) determining the DL CC for which aperiodic CSI reporting is to be triggered; and
(3) mapping the CSI request field in the uplink grant according to the pre-assigned
corresponding relationship to mark the value of the bit corresponding to the determined DL
CC as "trigger".
2. The method according to Claim 1, wherein step (1) further comprises:
dividing all DL CCs of the user equipment UE into multiple subsets and corresponding
different bits of the CSI request field to different subsets; and
step (3) further comprises:
marking the value of a bit corresponding to a subset to which the DL CC as determined
in step (2) belongs as "trigger".
3. The method according to Claim 2, wherein the number of bits of the CSI request
field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
4. The method according to Claim 1, wherein step (1) further comprises:
corresponding one bit of the CSI request field in the uplink grant to the DL CC that is
carrying the uplink grant, and corresponding the remaining bits to different DL CCs according
to a priority order of DL CCs or CC serial numbers given by upper layer signaling; and
step (3) further comprises:
marking the value of a bit corresponding to the DL CC determined in step (2) as"trigger" during mapping of the CSI request field.
5. The method according to Claim 4, wherein DL CCs corresponding to the
remaining bits do not include a DL CC that has a paired uplink component carrier UL CC on
which there is data transmission on an uplink shared channel UL SCH.
6. The method according to Claim 5, further comprising:
when one uplink grant is not sufficient to trigger CSI reporting for all DL CCs
determined in step (2), sending multiple single-bit triggering uplink grants in the same
subframe as the first uplink grant or in a subsequent subframe.
7. A reporting method of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the CSI request field in
an uplink grant and multiple downlink component carriers DL CCs of user equipment,
wherein the number of bits of the CSI request field is greater than 1 and less than the
maximum allowed number of DL CCs in the system; and
(2) demapping, according to the pre-assigned corresponding relationship, the CSI
request field in the received uplink grant so as to determine the DL CC for which aperiodic
CSI reporting will be implemented.
8. The method according to Claim 7, wherein step (1) further comprises:
dividing all DL CCs of the user equipment UE into multiple subsets and corresponding
different bits of the CSI request field to different subsets; and
step (2) further comprises:
determining that aperiodic CSI reporting is to be implemented for all DL CCs in the
subset corresponding to the bit that is marked as "trigger" in the CSI request field.
9. The method according to Claim 8, wherein the number of bits of the CSI request
field is equal to the number of subsets into which DL CCs are divided, and each bitcorresponds to a different subset.
10. The method according to Claim 7, wherein step (1) further comprises:
corresponding one bit of the CSI request field in the uplink grant to the DL CC that is
carrying the uplink grant, and corresponding the remaining bits to different DL CCs according
to a priority order of DL CCs or CC serial numbers given by upper layer signaling; and
step (2) further comprises:
determining that aperiodic CSI reporting is to be implemented for the DL CC
corresponding to the bit that is marked as "trigger" in the CSI request field.
11. The method according to Claim 10, wherein DL CCs corresponding to the
remaining bits do not include a DL CC that has a paired uplink component carrier UL CC on
which there is data transmission on an uplink shared channel UL SCH.
12. A triggering apparatus of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
first pre-assigning means, for pre-assigning a corresponding relationship between bits
of the CSI request field in an uplink grant and multiple downlink component carriers DL CCs
of user equipment, wherein the number of bits of the CSI request field is greater than 1 and
less than the maximum allowed number of DL CCs in the system;
first determining means, for determining the DL CC for which aperiodic CSI reporting
is to be triggered; and
mapping means, for mapping the CSI request field in the uplink grant according to the
pre-assigned corresponding relationship to mark the value of the bit corresponding to the
determined DL CC as "trigger".
13. The apparatus according to Claim 12, wherein the first pre-assigning means is
further for dividing all DL CCs of the user equipment UE into multiple subsets and
corresponding different bits of the CSI request field to different subsets; and
the mapping means is further for marking the value of a bit corresponding to a subset towhich the DL CC as determined by the first determining means belongs as "trigger".
14. The apparatus according to Claim 13, wherein the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
15. The apparatus according to Claim 12, wherein the first pre-assigning means is
further for corresponding one bit of the CSI request field in the uplink grant to the DL CC that
is carrying the uplink grant, and for corresponding the remaining bits to different DL CCs
according to a priority order of DL CCs or CC serial numbers given by upper layer signaling;
and
the mapping means is further for marking the value of a bit corresponding to the DL
CC determined by the first determining means as "trigger" during mapping of the CSI request
field.
16. The apparatus according to Claim 15, wherein DL CCs corresponding to the
remaining bits do not include a DL CC that has a paired uplink component carrier UL CC on
which there is data transmission on an uplink shared channel UL SCH.
17. A reporting apparatus of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
second pre-assigning means, for pre-assigning a corresponding relationship between
bits of the CSI request field in an uplink grant and multiple downlink component carriers DL
CCs of user equipment, wherein the number of bits of the CSI request field is greater than 1
and less than the maximum allowed number of DL CCs in the system; and
second determining means, for demapping, according to the pre-assigned
corresponding relationship, the CSI request field in the received uplink grant so as to
determine the DL CC for which aperiodic CSI reporting will be implemented.
18. The apparatus according to Claim 17, wherein the second pre-assigning means is
further for dividing all DL CCs of the user equipment UE into multiple subsets andcorresponding different bits of the CSI request field to different subsets; and
the second determining means is further for determining that aperiodic CSI reporting is
to be implemented for all DL CCs in the subset corresponding to the bit that is marked as
"trigger" in the CSI request field.
19. The apparatus according to Claim 18, wherein the number of bits of the CSI
request field is equal to the number of subsets into which DL CCs are divided, and each bit
corresponds to a different subset.
20. The apparatus according to Claim 17, wherein the second pre-assigning means is
further for corresponding one bit of the CSI request field in the uplink grant to the DL CC that
is carrying the uplink grant, and corresponding the remaining bits to different DL CCs
according to a priority order of DL CCs or CC serial numbers given by upper layer signaling;
and
the second determining means is further for determining that aperiodic CSI reporting is
to be implemented for the DL CC corresponding to the bit that is marked as "trigger" in the
CSI request field.
21. The apparatus according to Claim 20, wherein DL CCs corresponding to the
remaining bits do not include a DL CC that has a paired uplink component carrier UL CC on
which there is data transmission on an uplink shared channel UL SCH.
22. A triggering method of an aperiodic uplink sounding reference signal SRS for a
carrier aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the SRS request field in
an uplink grant and multiple uplink component carriers UL CCs of user equipment, wherein
the number of bits of the SRS request field is greater than 1 and less than the maximum
allowed number of UL CCs in the system;
(2) determining the UL CC for which aperiodic SRS is to be triggered; and
(3) mapping the SRS request field in the uplink grant according to the pre-assigned
corresponding relationship to mark the value of a bit corresponding to the determined UL CCas "trigger".
23. The method according to Claim 22, wherein step (1) further comprises:
dividing all UL CCs of the user equipment UE into multiple subsets and corresponding
different bits of the SRS request field to different subsets; and
step (3) further comprises:
marking the value of a bit corresponding to a subset to which the UL CC as determined
in step (2) belongs as "trigger".
24. The method according to Claim 22, wherein step (1) further comprises:
corresponding one bit of the SRS request field in the uplink grant to the CC that is
specified by the carrier indicator field in the same uplink grant, and corresponding the
remaining bits to different UL CCs according to a priority order of UL CCs or CC serial
numbers given by upper layer signaling; and
step (3) further comprises:
marking the value of a bit corresponding to the UL CC determined in step (2) as
"trigger" during mapping of the SRS request field.
25. A transmission method of an aperiodic uplink sounding reference signal SRS for
a carrier aggregation system, comprising:
(1) pre-assigning a corresponding relationship between bits of the SRS request field in
an uplink grant and multiple uplink component carriers UL CCs of user equipment, wherein
the number of bits of the SRS request field is greater than 1 and less than the maximum
allowed number of UL CCs in the system; and
(2) demapping, according to the pre-assigned corresponding relationship, the SRS
request field in the received uplink grant so as to determine the UL CC for which SRS
transmission will be implemented.
26. The method according to Claim 25, wherein step (1) further comprises:
dividing all UL CCs of the user equipment UE into multiple subsets and correspondingdifferent bits of the SRS request field to different subsets; and
step (2) further comprises:
determining that SRS transmission is to be implemented on all UL CCs in the subset
corresponding to the bit that is marked as "trigger" in the SRS request field.
27. The method according to Claim 25, wherein step (1) further comprises:
corresponding one bit of the SRS request field in the uplink grant to the CC that is
specified by the carrier indicator field in the same uplink grant, and corresponding the
remaining bits to different UL CCs according to a priority order of UL CCs or CC serial
numbers given by upper layer signaling; and
step (2) further comprises:
determining that SRS transmission is to be implemented on the UL CC corresponding
to the bit that is marked as "trigger" in the SRS request field.
28. A triggering apparatus of an aperiodic uplink sounding reference signal SRS for a
carrier aggregation system, comprising:
third pre-assigning means, for pre-assigning a corresponding relationship between bits
of the SRS request field in an uplink grant and multiple uplink component carriers UL CCs of
user equipment, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system;
third determining means, for determining the UL CC for which aperiodic SRS is to be
triggered; and
third mapping means, for mapping the SRS request field in the uplink grant according
to the pre-assigned corresponding relationship to mark the value of a bit corresponding to the
determined UL CC as "trigger".
29. The apparatus according to Claim 28, wherein the third pre-assigning means further
divides all UL CCs of the user equipment UE into multiple subsets and corresponds different
bits of the SRS request field to different subsets; and
the third mapping means further marks the value of a bit corresponding to a subset towhich the UL CC as determined by the third determining means belongs as "trigger".
30. The apparatus according to Claim 28, wherein the third pre-assigning means
further corresponds one bit of the SRS request field in the uplink grant to the CC that is
specified by the carrier indicator field in the same uplink grant, and corresponds the
remaining bits to different UL CCs according to a priority order of UL CCs or CC serial
numbers given by upper layer signaling; a d
the third mapping means further marks the value of a bit corresponding to the UL CC
determined by the third determining means as "trigger" during mapping of the SRS request
field.
31. A transmission apparatus of an aperiodic uplink sounding reference signal SRS
for a carrier aggregation system, comprising:
fourth pre-assigning means, for pre-assigning a corresponding relationship between bits
of the SRS request field in an uplink grant and multiple uplink component carriers UL CCs of
user equipment, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system; and
fourth determining means, for demapping, according to the pre-assigned corresponding
relationship, the SRS request field in the received uplink grant so as to determine the UL CC
for which SRS transmission will be implemented.
32. The apparatus according to Claim 31, wherein the fourth pre-assigning means
further divides all UL CCs of the user equipment UE into multiple subsets and corresponds
different bits of the SRS request field to different subsets; and
the fourth determining means further determines that SRS transmission is to be
implemented on all UL CCs in the subset corresponding to the bit that is marked as "trigger"
in the SRS request field.
33. The apparatus according to Claim 31, wherein the fourth pre-assigning means
further corresponds one bit of the SRS request field in the uplink grant to the CC that is
specified by the carrier indicator field in the same uplink grant, and corresponds theremaining bits to different UL CCs according to a priority order of UL CCs or CC serial
numbers given by upper layer signaling; and
the fourth determining means further determines that SRS transmission is to be
implemented on the UL CC corresponding to the bit that is marked as "trigger" in the SRS
request field.
34. A triggering method of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) pre-assigning a mapping relationship between different values of the CSI request
field in an uplink grant and CSI requests for different combinations of downlink component
carriers DL CCs, wherein the number of bits of the CSI request field is greater than 1 and less
than the maximum allowed number of DL CCs in the system;
(2) determining the DL CC for which aperiodic CSI reporting is to be triggered; and
(3) populating value of the CSI request field in the uplink grant according to the
pre-assigned mapping relationship and the determined DL CC.
35. The method according to Claim 34, wherein the mapping relationship comprises:
mapping a first value of the CSI request field to indicate that CSI reporting for the DL CC
carrying the uplink grant is to be triggered, and mapping a second value of the CSI request
field to indicate that CSI reporting for all DL CCs is to be triggered.
36. A reporting method of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) pre-assigning a mapping relationship between different values of the CSI request
field in an uplink grant and CSI requests for different combinations of downlink component
carriers DL CCs, wherein the number of bits of the CSI request field is greater than 1 and less
than the maximum allowed number of DL CCs in the system; and
(2) demapping, according to the pre-assigned mapping relationship, the CSI request
field in the received uplink grant so as to determine the DL CC for which aperiodic CSI
reporting is to be implemented.37. The method according to Claim 36, wherein the mapping relationship comprises:
mapping a first value of the CSI request field to indicate that CSI reporting for the DL CC
carrying the uplink grant is to be triggered, and mapping a second value of the CSI request
field to indicate that CSI reporting for all DL CCs is to be triggered.
38. A triggering apparatus of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) fifth pre-assigning means, for pre-assigning a mapping relationship between
different values of the CSI request field in an uplink grant and CSI requests for different
combinations of downlink component carriers DL CCs, wherein the number of bits of the CSI
request field is greater than 1 and less than the maximum allowed number of DL CCs in the
system;
(2) fifth determining means, for determining the DL CC for which aperiodic CSI
reporting is to be triggered; and
(3) fifth mapping means, for populating value of the CSI request field in the uplink
grant according to the pre-assigned mapping relationship and the determined DL CC.
39. A reporting apparatus of aperiodic channel state information CSI for a carrier
aggregation system, comprising:
(1) sixth pre-assigning means, for pre-assigning a mapping relationship between
different values of the CSI request field in an uplink grant and CSI requests for different
combinations of downlink component carriers DL CCs, wherein the number of bits of the CSI
request field is greater than 1 and less than the maximum allowed number of DL CCs in the
system; and
(2) sixth determining means, for demapping, according to the pre-assigned mapping
relationship, the CSI request field in the received uplink grant so as to determine the DL CC
for which aperiodic CSI reporting is to be implemented.
40. A triggering method of an aperiodic uplink sounding reference signal SRS for a
carrier aggregation system, comprising:
(1) pre-assigning a mapping relationship between different values of the SRS requestfield in an uplink grant and SRS requests for different combinations of uplink component
carriers UL CCs, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system;
(2) determining the UL CC for which aperiodic SRS is to be triggered; and
(3) populating values of the SRS request field in the uplink grant according to the
pre-assigned mapping relationship and the determined UL CC.
41. The method according to Claim 40, wherein the mapping relationship comprises:
mapping a first value of the SRS request field to indicate that SRS transmission on the CC
specified by the carrier indicator field in the uplink grant is to be triggered, and mapping a
second value of the SRS request field to indicate that SRS transmission on all UL CCs is to be
triggered.
42. A transmission method of an aperiodic uplink sounding reference signal SRS for
a carrier aggregation system, comprising:
(1) pre-assigning a mapping relationship between different values of the SRS request
field in an uplink grant and SRS requests for different combinations of uplink component
carriers UL CCs, wherein the number of bits of the SRS request field is greater than 1 and less
than the maximum allowed number of UL CCs in the system; and
(2) demapping, according to the pre-assigned mapping relationship, the SRS request
field in the received uplink grant so as to determine a UL CC on which SRS transmission is to
be implemented.
43. The method according to Claim 42, wherein the mapping relationship comprises:
mapping a first value of the SRS request field to indicate that SRS transmission on the CC
specified by the carrier indicator field in the uplink grant is to be triggered, and mapping a
second value of the SRS request field to indicate that SRS transmission on all UL CCs is to be
triggered.
44. A triggering apparatus of an aperiodic uplink sounding reference signal SRS for a
carrier aggregation system, comprising:(1) seventh pre-assigning means, for pre-assigning a mapping relationship between
different values of the SRS request field in an uplink grant and SRS requests for different
combinations of uplink component carriers UL CCs, wherein the number of bits of the SRS
request field is greater than 1 and less than the maximum allowed number of UL CCs in the
system;
(2) seventh determining means, for determining the UL CC for which aperiodic SRS is
to be triggered; and
(3) seventh mapping means, for populating values of the SRS request field in the uplink
grant according to the pre-assigned mapping relationship and the determined UL CC.
45. A transmission apparatus of an aperiodic uplink sounding reference signal SRS
for a carrier aggregation system, comprising: