U.S. patent application number 13/103612 was filed with the patent office on 2011-11-10 for method and apparatus for handling dynamic aperiodic srs (sounding reference signal) in a wireless communication network.
Invention is credited to Ming-Che Li.
Application Number | 20110274063 13/103612 |
Document ID | / |
Family ID | 44901856 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110274063 |
Kind Code |
A1 |
Li; Ming-Che |
November 10, 2011 |
METHOD AND APPARATUS FOR HANDLING DYNAMIC APERIODIC SRS (SOUNDING
REFERENCE SIGNAL) IN A WIRELESS COMMUNICATION NETWORK
Abstract
A method and apparatus are disclosed for handling SRS and PUCCH
in a wireless communication system. In one embodiment, the method
comprises using a PDCCH transmission to trigger a dynamic aperiodic
SRS transmission. In addition, the method comprises transmitting
the triggered dynamic aperiodic SRS transmission in a first
subframe. Furthermore, the method comprises transmitting a PUCCH
transmission in the same first subframe.
Inventors: |
Li; Ming-Che; (Taipei,
TW) |
Family ID: |
44901856 |
Appl. No.: |
13/103612 |
Filed: |
May 9, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61332825 |
May 10, 2010 |
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04L 5/0053 20130101;
H04W 84/12 20130101; H04L 1/1607 20130101; H04L 5/001 20130101;
H04L 5/0023 20130101; H04W 72/1289 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 72/04 20090101
H04W072/04 |
Claims
1. A method for handling SRS and PUCCH a wireless communication
system, comprising: using a PDCCH transmission to trigger a dynamic
aperiodic SRS transmission; transmitting the triggered dynamic
aperiodic SRS transmission in a first subframe; and transmitting a
PUCCH transmission in the same first subframe.
2. The method of claim 1, wherein the PUCCH transmission is for a
scheduling request.
3. The method of claim 1, wherein the PUCCH transmission is for
HARQ-ACK.
4. The method of claim 1, wherein the PUCCH transmission is for
periodic CQI/PMI/RI reporting.
5. The method of claim 1, further comprises: determining Whether to
use a shortened PUCCH format in the PUCCH transmission based on a
parameter.
6. The method of claim 5, further comprises: using the shortened
PUCCH format in the PUCCH transmission if the parameter is
ackNackSRS-SimultaneousTransmission.
7. The method of claim 1, wherein the dynamic aperiodic SRS
transmission and the PUCCH transmission are transmitted on a
UL.
8. The method of claim 1, wherein the dynamic aperiodic SRS
transmission is triggered by a PDCCH UL grant.
9. The method of claim 1, wherein the dynamic aperiodic SRS
transmission is triggered by a PDCCH DL assignment.
10. The method of claim 1, further comprises: dropping a periodic
SRS transmission if the subframe is requested to transfer the
dynamic aperiodic SRS transmission and the periodic SRS
transmission.
11. A method for handling SRS and PUCCH a wireless communication
system, comprising: using a PDCCH transmission to trigger a dynamic
aperiodic SRS transmission; transmitting the triggered dynamic
aperiodic SRS transmission in a first subframe; transmitting a
PUCCH transmission in the same first subframe; and dropping a
periodic SRS transmission if the subframe is requested to transfer
the dynamic aperiodic SRS transmission and the periodic SRS
transmission.
12. The method of claim 11, further comprises: determining whether
to use a shortened PUCCH format in the PUCCH transmission based on
a parameter.
13. An apparatus to handle SRS and PUCCH a wireless communication
system, comprising: a first module to trigger a dynamic aperiodic
SRS transmission through a PDCCH transmission; a second module to
transmit the triggered dynamic aperiodic SRS transmission in a
first subframe; and a third module to transmit a PUCCH transmission
in the same first subframe.
14. The apparatus of claim 13, wherein the PUCCH transmission is
for a scheduling request.
15. The apparatus of claim 13, wherein the PUCCH transmission is
for HARQ-ACK.
16. The apparatus of claim 13, wherein the PUCCH transmission is
for periodic CQI/PMI/RI reporting.
17. The apparatus of claim 13, further comprises: a fourth module
to drop a periodic SRS transmission if the subframe is requested to
transfer the dynamic aperiodic SRS transmission and the periodic
SRS transmission.
18. The apparatus of claim 13, further comprises: a fifth module to
determine whether to use a shortened PUCCH format in PUCCH
transmission based on a parameter.
19. The apparatus of claim 13, wherein the dynamic aperiodic SRS
transmission is triggered by a PDCCH UL grant.
20. The apparatus of claim 13, wherein the dynamic aperiodic SRS
transmission is triggered by a PDCCH DL assignment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application for patent claims the benefit of
U.S. Provisional Patent Application Ser. No. 61/332,825, filed on
May 10, 2010, entitled "Method and Apparatus of Handling Dynamic
Aperiodic SRS in a Wireless Communication System".
FIELD
[0002] This disclosure relates generally to a method and apparatus
to handle and process dynamic aperiodic SRS in a wireless
communication network.
BACKGROUND
[0003] In LTE, Single Carrier Frequency Division Multiple Access
(SC-FDMA) transmission was selected for uplink (UL) direction. A
wireless transmit/receive unit (WTRU) in the UL will transmit only
on a limited, contiguous set of assigned sub-carriers in an FDMA
arrangement. The WTRU transmits its their UL data (and in some
cases their control information) on the physical uplink shared
channel (PUSCH). The transmission of the PUSCH is scheduled and
controlled by the eNodeB using the so-called uplink scheduling
grant.
[0004] An evolved NodeB (eNodeB or eNB) would receive the composite
UL signal across the entire transmission bandwidth from one or more
WTRUs at the same time, but each WTRU would only transmit into a
subset of the available transmission bandwidth. In order to allow
for the eNodeB to estimate UL channel quality for UL scheduling,
sounding reference signals (SRS) may be transmitted in UL. When an
SRS is to be transmitted in a subframe, it occupies the last
SC-FDMA symbol of the subframe. If a WTRU is transmitting SRS in a
certain subframe, then the last symbol of the subframe is then not
used for PUSCH transmission by any WTRU within the cell.
[0005] It would be beneficial to provide a method and apparatus to
guarantee the triggered dynamic aperiodic SRS transmission could be
guaranteed.
SUMMARY
[0006] A method and apparatus are disclosed for handling SRS and
PUCCH in a wireless communication system. In one embodiment, the
method comprises using, a PDCCH transmission to trigger a dynamic
aperiodic SRS transmission. In addition, the method comprises
transmitting the triggered dynamic aperiodic SRS transmission in a
first subframe. Furthermore, the method comprises transmitting a
PUCCH transmission in the same first subframe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows a multiple access wireless communication system
according to one embodiment of the invention.
[0008] FIG. 2 is a block diagram of an embodiment of a transmitter
system (also known as the access network (AN)) and a receiver
system (also known as access terminal (AT) or user equipment (UE))
according to one embodiment of the invention.
[0009] FIG. 3 shows an alternative functional block diagram of a
communication device according to one embodiment of the
invention.
[0010] FIG. 4 is a simplified block diagram of the program code
shown in FIG. 3 according to one embodiment of the invention.
[0011] FIG. 5 is a simplified block diagram of a wireless
communication system from an alternative perspective according to
one embodiment of the invention.
[0012] FIG. 6 outlines an exemplary flow diagram for handling
dynamic aperiodic SRS according to one embodiment of the
invention.
DETAILED DESCRIPTION
[0013] The exemplary wireless communication systems and devices
described below employ a wireless communication system, supporting
a broadcast service. Wireless communication systems are widely
deployed to provide various types of communication such as voice,
data, and so on. These systems may be based on code division
multiple access (CDMA), time division multiple access (TDMA),
orthogonal frequency division multiple access (OFDMA), 3GPP LTE
(Long Term Evolution) wireless access, 3GPP LTE-A (Long Term
Evolution Advanced) wireless access, 3GPP2 UMB (Ultra Mobile
Broadband), WiMax, or some other modulation techniques.
[0014] In particular, the exemplary wireless communication systems
devices described below may be designed to support one or more
standards such as the standard offered by a consortium named "3rd
Generation Partnership Project" referred to herein as 3GPP,
including 3GPP TSG RAN WG1 #61 ("Signaling Considerations for
Dynamic Aperiodic SRS"--R1-102830). The standards and documents
listed above are hereby expressly incorporated herein.
[0015] FIG. 1 shows a multiple access wireless communication system
according to one embodiment of the invention. An access network 100
(AN) includes multiple antenna groups, one including 104 and 106,
another including 108 and 110, and an additional including 112 and
114. In Figure A1, only two antennas are shown for each antenna
group, however, more or fewer antennas may be utilized for each
antenna group. Access terminal 116 (AT) is in communication with
antennas 112 and 114, where antennas 112 and 114 transmit
information to access terminal 116 over forward link 120 and
receive information from access terminal 116 over reverse link 118.
Access terminal (AT) 122 is in communication with antennas 106 and
108, where antennas 106 and 108 transmit information to access
terminal (AT) 122 over forward link 126 and receive information
from access terminal (AT) 122 over reverse link 124. In a FDD
system, communication links 118, 120, 124 and 126 may use different
frequency for communication. For example, forward link 120 may use
a different frequency than that used by reverse link 118.
[0016] Each group of antennas and/or the area in which they are
designed to communicate is often referred to as a sector of the
access network. In the embodiment, antenna groups each are designed
to communicate to access terminals in a sector of the areas covered
by access network 100.
[0017] In communication over forward links 120 and 126, the
transmitting antennas of access network 100 may utilize beamforming
in order to improve the signal-to-noise ratio of forward links for
the different access terminals 116 and 122. Also, an access network
using beamforming to transmit to access terminals scattered
randomly through its coverage normally causes less interference to
access terminals in neighboring cells than an access network
transmitting through a single antenna to all its access
terminals.
[0018] An access network (AN) may be a fixed station or base
station used for communicating with the terminals and may also be
referred to as an access point, a Node B, a base station, an
enhanced base station, an eNodeB, or some other terminology. An
access terminal (AT) may also be called user equipment (UE), a
wireless communication device, terminal, access terminal or some
other terminology.
[0019] FIG. 2 is a simplified block diagram of an embodiment of a
transmitter system 210 (also known as the access network) and a
receiver system 250 (also known as access terminal (AT) or user
equipment (UE)) in a MIMO system 200. At the transmitter system
210, traffic data for a number of data streams is provided from a
data source 212 to a transmit (TX) data processor 214.
[0020] In one embodiment, each data stream is transmitted over a
respective transmit antenna. TX data processor 214 formats, codes,
and interleaves the traffic data for each data stream based on a
particular coding scheme selected for that data stream to provide
coded data.
[0021] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data is typically a
known data pattern that is processed in a known manner and may be
used at the receiver system to estimate the channel response. The
multiplexed pilot and coded data for each data stream is then
modulated (i.e., symbol mapped) based on a particular modulation
scheme (e.g. BPSK. QPSK, M-PSK, or M-QAM) selected for that data
stream to provide modulation symbols. The data rate, coding, and
modulation for each data stream may be determined by instructions
performed by processor 230.
[0022] The modulation symbols for all data streams are then
provided to a TX MIMO processor 220, which may further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 220 then
provides N.sub.T modulation symbol streams to N.sub.T transmitters
(TMTR) 222a through 222t. In certain embodiments, TX MIMO processor
220 applies beamforming weights to the symbols of the data streams
and to the antenna from which the symbol is being transmitted.
[0023] Each transmitter 222 receives and processes a respective
symbol stream to provide one or more analog signals, and further
conditions (e.g., amplifies, filters, and upconverts) the analog
signals to provide a modulated signal suitable for transmission
over the MIMO channel. N.sub.T modulated signals from transmitters
222a through 222t are then transmitted from N.sub.T antennas 224a
through 224t, respectively.
[0024] At receiver system 250, the transmitted modulated signals
are received by N.sub.R antennas 252a through 252r and the received
signal from each antenna 252 is provided to a respective receiver
(RCVR) 254a through 254r. Each receiver 254 conditions (e.g.,
filters, amplifies, and downconverts) a respective received signal,
digitizes the conditioned signal to provide samples, and further
processes the samples to provide a corresponding "received" symbol
stream.
[0025] An RX data processor 260 then receives and processes the
N.sub.R received symbol streams from N.sub.R receivers 254 based on
a particular receiver processing technique to provide N.sub.T
"detected" symbol streams. The RX data processor 260 then
demodulates, deinterleaves, and decodes each detected symbol stream
to recover the traffic data for the data stream. The processing by
RX data processor 260 is complementary to that performed by TX MIMO
processor 220 and TX data processor 214 at transmitter system
210.
[0026] A processor 270 periodically determines which pre-coding
matrix to use (discussed below). Processor 270 formulates a reverse
link message comprising a matrix index portion and a rank value
portion.
[0027] The reverse link message may comprise various types of
information regarding the communication link and/or the received
data stream. The reverse link message is then processed by a TX
data processor 238, which also receives traffic data for a number
of data streams from a data source 236, modulated by a modulator
280, conditioned by transmitters 254a through 254r, and transmitted
back to transmitter system 210.
[0028] At transmitter system 210, the modulated signals from
receiver system 250 are received by antennas 224, conditioned by
receivers 222, demodulated by a demodulator 240, and processed by a
RX data processor 242 to extract the reserve link message
transmitted by the receiver system 250. Processor 230 then
determines which pre-coding matrix to use for determining the
beamforming weights then processes the extracted message.
[0029] Memory 232 may be used to temporarily store some
buffered/computational data from 240 or 242 through Processor 230,
store some buffed data from 212, or store some specific program
codes. And Memory 272 may be used to temporarily store some
buffered/computational data from 260 through Processor 270, store
some buffed data from 236, or store some specific program
codes.
[0030] Turning to FIG. 3, this figure shows an alternative
simplified functional block diagram of a communication device
according to one embodiment of the invention. As shown in FIG. 3,
the communication device 300 in a wireless communication system can
be utilized for realizing the UEs (or ATs) 116 and 122 in FIG. 1,
and the wireless communications system is preferably the LTE
system. The communication device 300 may include an input device
302, an output device 304, a control circuit 306, a central
processing unit (CPU) 308, a memory 310, a program code 312, and a
transceiver 314. The control circuit 306 executes the program code
312 in the memory 310 through the CPU 308, thereby controlling an
operation of the communications device 300. The communications
device 300 can receive signals input by a user through the input
device 302, such as a keyboard or keypad, and can output images and
sounds through the output device 304, such as a monitor or
speakers. The transceiver 314 is used to receive and transmit
wireless signals, delivering received signals to the control
circuit 306, and outputting signals generated by the control
circuit 306 wirelessly.
[0031] FIG. 4 is a simplified block diagram of the program code 312
shown in FIG. 3 in accordance with one embodiment of the invention.
In this embodiment, the program code 312 includes an application
layer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and is
coupled to a Layer 1 portion 406. The Layer 3 portion 402 generally
performs radio resource control. The Layer 2 portion 404 generally
performs link control. The Layer 1 portion 406 generally performs
physical connections.
[0032] For LTE or LTE-A system, the Layer 2 portion 404 may include
a Radio Link Control (RLC) layer and a Medium Access Control (MAC)
layer. The Layer 3 portion 402 may include a Radio Resource Control
(RRC) layer.
[0033] FIG. 5 is a simplified block diagram of a wireless
communication system from an alternative perspective. As shown, the
system 500 includes the WTRU (wireless transmit/receive unit) 530,
the eNB 510, and the MME/S-GW (Mobility Management Entity/Serving
GateWay) 520. The WTRU 530, the eNB 510 and the MME/S-GW 520 are
configured to perform SRS transmission with MIMO and carrier
aggregation techniques.
[0034] In addition to the components that may be found in a typical
WTRU, the WTRU 530 includes a processor or CPU 532 with an optional
memory 534, one or more one transceivers 536.sub.1, . . . ,
536.sub.N, and an antenna 538. The CPU 532 is configured to perform
a method of SRS transmission with MIMO and carrier aggregation
techniques. The transceivers 536.sub.1, . . . , 536.sub.N are in
communication with the CPU or processor 532 and the antenna 538 to
facilitate the transmission and reception of wireless
communications.
[0035] In addition to the components that may be found in a typical
eNB, the eNB 510 includes a processor or CPU 512 with an optional
memory 514, one or more transceivers 516.sub.1, . . . , 516.sub.M,
and an antenna 518. The CPU 512 is configured to support SRS
functionality with (MIMO) and carrier aggregation techniques. The
transceivers 516.sub.1, . . . , 516.sub.M are in communication with
the CPU 512 and an antennas 518 to facilitate the transmission and
reception of wireless communications. The CPU is generally
configured to: i) determine which WTRUs will be transmitting SRS,
ii) determine each WTRU's allocation in frequency and time for SRS
transmission, as well as the type of SRS transmission and
communicate this information to the WTRUs, iii) receive the SRS
measurement information and iv) process the SRS information and
inform the scheduler so that the scheduler can make scheduling
decisions. The eNB 520 is connected to the MME/S-GW 520 which
includes a processor 522 with an optional memory 524.
[0036] In the following discussion, the invention will be described
mainly in the context of the 3GPP architecture reference model.
However, it is understood that with the disclosed information, one
skilled in the art could easily adapt for use and implement aspects
of the invention in a 3GPP2 network architecture as well as in
other network architectures.
[0037] In LTE, there is a single transmission of a physical uplink
control channel (PUCCH). Physical Uplink Shared Channel (PUSCH), or
Sounding Reference Signals (SRSs) with a single antenna and a
single carrier. The WTRU does not transmit SRS whenever SRS and
PUCCH format 2/a/2b transmission happen to coincide in the same
subframe. The WTRU does not transmit SRS whenever SRS and
acknowledge/negative acknowledge (ACK/NACK) and/or positive SR
transmissions happen to coincide in the same subframe unless the
parameter Simultaneous-AN-and-SRS is true. The parameter
Simultaneous-AN-and-SRS provided by a higher layer determines if a
WTRU is configured to support the transmission of ACK/NACK on PUCCH
and SRS in one subframe. If it is configured to support the
transmission of ACK/NACK on PUCCH and SRS in one subframe, then in
the cell specific SRS subframes WTRU shall transmit ACK/NACK and SR
using the shortened PUCCH format, in which the ACK/NACK or the SR
transmission on the SC-FDMA symbol corresponding to the SRS is
punctured. More specifically, the SC-FDMA is a timing unit, and not
a modulation symbol. In addition, when the shortened PUCCH format
is used or applied, the PUCCH transmission would be punctured in
the last SC-FDMA symbol. Also, since the time is used for possible
SRS transmission, no ACK/NACK modulation symbol will be generated
to avoid transmission overlapping.
[0038] Furthermore, in order for the eNodeB to perform reliable
channel estimation for frequency-scheduling for each UL, the
transmit power for SRS (and other channels) is controlled.
[0039] Additionally, in LTE, Single Carrier Frequency Division
Multiple Access (SC-FDMA) transmission was selected for uplink (UL)
direction. The specific implementation is based on Discrete Fourier
Transform Spread Orthogonal Frequency Division Multiplexing
(DFT-S--OFDM). For the purpose of this application, either term may
be used interchangeably. A WTRU in the UL will transmit only on a
limited, contiguous set of assigned sub-carriers in an FDMA
arrangement. For illustration purposes, if the overall OFDM signal
or system bandwidth in the UL is composed of useful sub-carriers
numbered 1 to 100, a first given WTRU would be assigned to transmit
its own signal on sub-carriers 1-12, a second given WTRU would
transmit on sub-carriers 13-24, and so on. An eNodeB (or eNB) would
receive the composite UL signal across the entire transmission
bandwidth from one or more WTRUs at the same time, but each WTRU
would only transmit into a subset of the available transmission
bandwidth. DFT-S OFDM in the LTE UL was selected by 3GPP Radio
Layer 1 (RAN1) as a form of OFDM transmission with the additional
constraint that the time-frequency resource assigned to a WTRU must
consist of a set of frequency-consecutive sub-carriers. In the LTE
UL, there is no DC sub-carrier (unlike the downlink (DL)).
Frequency hopping may be applied in one mode of operation to UL
transmissions by a WTRU.
[0040] WTRUs transmit their UL data (and in some cases their
control information) on the physical uplink shared channel (PUSCH).
The transmission of the PUSCH is scheduled and controlled by the
eNodeB using the so-called uplink scheduling grant, which is
carried on physical downlink control channel (PDCCH) format 0. As
part of the uplink scheduling grant, the WTRU receives control
information on the modulation and coding scheme (MCS), transmit
power control (TPC) command, uplink resources allocation (i.e., the
indices of allocated resource blocks), etc. Then, the WTRU will
transmit its PUSCH on allocated uplink resources with corresponding
MCS at transmit power controlled by the TPC command.
[0041] Similar to LIE DL, reference signals for channel estimation
are also needed for the LTE UL to enable coherent demodulation of
PUSCH (or PUCCH) at the eNodeB. These reference signals are
referred to as UL demodulation reference signals (DRS). They are
always transmitted together with and covering the same frequency
band as PUSCH (or PUCCH).
[0042] To allow for the eNodeB to estimate UL channel quality for
UL scheduling, sounding reference signals (SRS) may be transmitted
in UL. In the frequency domain. SRS transmissions may cover the
frequency band that is of interest for the frequency domain
scheduling. When an SRS is to be transmitted in a subframe, it
occupies the last SC-FDMA symbol of the subframe. If a WTRU is
transmitting SRS in a certain subframe, then the last symbol of the
subframe is then not used for PUSCH transmission by any WTRU within
the cell. In order for the eNodeB to perform reliable channel
estimation for frequency-scheduling for each UL, the transmit power
for SRS (and other channels) is controlled.
[0043] In addition, from a UE perspective, there is one transport
block (in absence of spatial multiplexing) and one hybrid-ARQ
(Hybrid Automatic Repeat Request) entity per scheduled component
carrier. Each transport block is mapped to a single component
carrier. A UE may be scheduled over multiple component carriers
simultaneously. The design principles for downlink control
signaling of control region size and uplink and downlink resource
assignments can generally be described as following: (1) PDCCH
(Physical Downlink Control Channel) on a component carrier assigns
PDSCH (Physical Downlink Shared Channel) resources on the same
component carrier and PUSCH resources on a single linked UL
component carrier. (2) PDCCH on a component carrier can assign
PDSCH or PUSCH resources for one of multiple component
carriers.
[0044] In LTE, UE requires to transmit periodic SRS on the last
symbol to help eNB measure the UL channel. Since LTE-A supports
UL-MIMO, it is beneficial to trigger dynamic aperiodic SRS from
multiple antennas for timely channel information. The SRS resources
could be also utilized more efficiently. Base on RAN1 #60bis, the
dynamic aperiodic SRS should be triggered at least by a PDCCH UL
grant as follows:
[0045] In case of aperiodic sounding, triggering is at least by
PDCCH UL grants [0046] FFS how many bits/code points in the DCI
message are used (i.e. including whether a PUSCH grant is given at
the same time).
[0047] Triggering in DL assignment is FFS
[0048] Details of what is triggered are FFS
With respect to triggering in DL assignment. 3GPP TSG RAN WG1 #61
states as follows:
[0049] PUCCH restriction: for activation in an UL grant the SRS
could be time division multiplexed with PUSCH. On the other hand
activation in a PDCCH conveying a DL assignment in subframe n would
require SRS transmission in subframe n+k (k.gtoreq.4), similarly to
A/N transmission in response to a PDSCH reception or a PDCCH
signifying SPS release. Therefore, the UE must always be configured
for simultaneous ACK/NACK+SRS to puncture out the last symbol of
the ACK/NACK transmission or else the SRS is dropped. Furthermore,
if periodic CQI transmission coincides with the aperiodic SRS
transmission the SRS is dropped.
[0050] In LTE, due to single-carrier constraint, shortened format
or dropping is applied when periodic SRS coincides with PUCCH
(Physical Uplink Control Channel) as follows:
[0051] Periodic SRS and PUCCH 1/1a/1b (SR, A/N): [0052] If
parameter ackNackSRS-SimultaneousTransmission is FALSE, periodic
SRS is dropped. [0053] If parameter
ackNackSRS-SimultaneousTransmission is TRUE, periodic SRS is
transmitted, and shortened format is applied to PUCCH 1/1a/1b.
[0054] Periodic SRS and PUCCH format 2/2a/2b (CQI, A/N): [0055]
Periodic SRS is dropped.
[0056] Considering the coincidence of SRS and PUCCH, it would be
logical to apply the triggering behavior as described and discussed
in 3GPP TSG RAN WG1 #61 for LTE to LTE-A. First, even though
dynamic SRS could not be triggered by DL assignment, the
coincidence case is also possible for activation by UL grant.
Second, since dynamic aperiodic SRS is triggered by eNB, the
possible coincidence should be known by eNB, dropping triggered SRS
directly seems improper. Also considering the use scenario of
UL-MIMO, the channel quality seems quite good in general situation
(since uplink transmit diversity is not supported in Rel.10).
Transmitting SRS and PUCCH simultaneously on the last symbol seems
possible even though some power fall-back is required, and there
may be some impact on the SRS measurement on eNB side. Based on
this reasons, this PUCCH constraint seems improper to apply to
LTE-A directly.
[0057] Turning now to FIG. 6, this figure outlines an exemplary
flow diagram for handling dynamic aperiodic SRS according to one
embodiment of the invention. In step 602, a PDCCH is used to
trigger a dynamic aperiodic SRS transmission. In one embodiment,
the dynamic aperiodic SRS transmission could be triggered by a
PDCCH UL grant. In an alternative embodiment, the dynamic aperiodic
SRS transmission could be triggered by a PDCCH DL assignment.
[0058] In step 604, the triggered dynamic aperiodic SRS is
transmitted in a subframe. In an embodiment, the dynamic aperiodic
SRS transmits on a cell-specific SRS subframe. In step 606, a PUCCH
transmission is performed using the same subframe. In one
embodiment, the dynamic aperiodic SRS transmission and the PUCCH
transmission are done on a UL. In another embodiment, the PUCCH
transmission could be used to effectuate a scheduling request. The
PUCCH transmission could also be an acknowledgement for a hybrid
automatic repeat request (HARQ). Furthermore, the PUCCH
transmission could be used for periodic CQI (Channel Quality
Indicator)/PMI (Precoding Matrix Indicator)/RI (Rank Indication)
reporting. In an alternative embodiment, the said dynamic aperiodic
SRS has higher power priority than the PUCCH. More specifically, if
there the power required for transmission exceeds the CC-specific
maximum power, power reduction would first apply to the PUCCH
transmission. In vet another embodiment, some antennas (or antenna
ports) are used to transmit the dynamic aperiodic SRS while other
antennas (or antenna ports) are used to transmit the PUCCH. In
other words, the dynamic aperiodic SRS is transmitted on the
antennas which are not used to transmit the PUCCH.
[0059] In step 608, a parameter is used to determine whether a
shortened PUCCH format should be used in the PUCCH transmission. In
one embodiment, if the parameter is an
ackNackSRS-SimultaneousTransmission, the shortened PUCCH format is
used in the PUCCH transmission.
[0060] In an embodiment, there are two types of SRS transmissions
in LIE-A, including: (1) periodic SRS, and (2) dynamic aperiodic
SRS. In this embodiment, the dynamic aperiodic SRS transmission
would have higher priority than the periodic SRS transmission.
Therefore, in step 610, if both types of SRS transmission are
requested to be transmitted in the same subframe, the periodic SRS
transmission would be dropped, and the aperiodic SRS transmission
would be transmitted. In particular, the periodic SRS transmission
is dropped if the subframe is a UE-specific SRS subframe and the
dynamic aperiodic SRS corresponding to the subframe is
triggered.
[0061] Various aspects of the disclosure have been described above.
It should be apparent that the teachings herein may be embodied in
a wide variety of forms and that any specific structure, function,
or both being disclosed herein is merely representative. Based on
the teachings herein one skilled in the art should appreciate that
an aspect disclosed herein may be implemented independently of any
other aspects and that two or more of these aspects may be combined
in various ways. For example, an apparatus may be implemented or a
method may be practiced using any number of the aspects set forth
herein. In addition, such an apparatus may be implemented or such a
method may be practiced using other structure, functionality, or
structure and functionality in addition to or other than one or
more of the aspects set forth herein. As an example of some of the
above concepts, in some aspects concurrent channels may be
established based on pulse repetition frequencies. In some aspects
concurrent channels may be established based on pulse position or
offsets. In some aspects concurrent channels may be established
based on time hopping sequences. In some aspects concurrent
channels may be established based on pulse repetition frequencies,
pulse positions or offsets, and time hopping sequences.
[0062] Those of skill in the art would understand that information
and signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0063] Those of skill would further appreciate that the various
illustrative logical blocks, modules, processors, means, circuits,
and algorithm steps described in connection with the aspects
disclosed herein may be implemented as electronic hardware (e.g., a
digital implementation, an analog implementation, or a combination
of the two, which may be designed using source coding or some other
technique), various forms of program or design code incorporating
instructions (which may be referred to herein, for convenience, as
"software" or a "software module"), or combinations of both. To
clearly illustrate this interchangeability of hardware and
software, various illustrative components, blocks, modules,
circuits, and steps have been described above generally in terms of
their functionality. Whether such functionality is implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system. Skilled artisans
may implement the described functionality in varying ways for each
particular application, but such implementation decisions should
not be interpreted as causing a departure from the scope of the
present disclosure.
[0064] In addition, the various illustrative logical blocks,
modules, and circuits described in connection with the aspects
disclosed herein may be implemented within or performed by an
integrated circuit ("IC"), an access terminal, or an access point.
The IC may comprise a general purpose processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC),
a field programmable gate array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, electrical components, optical components, mechanical
components, or any combination thereof designed to perform the
functions described herein, and may execute codes or instructions
that reside within the IC, outside of the IC, or both. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices. e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0065] It is understood that any specific order or hierarchy of
steps in any disclosed process is an example of a sample approach.
Based upon design preferences, it is understood that the specific
order or hierarchy of steps in the processes may be rearranged
while remaining within the scope of the present disclosure. The
accompanying method claims present elements of the various steps in
a sample order, and are not meant to be limited to the specific
order or hierarchy presented.
[0066] The steps of a method or algorithm described in connection
with the aspects disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module (e.g., including
executable instructions and related data) and other data may reside
in a data memory such as RAM memory, flash memory, ROM memory,
EPROM memory, EEPROM memory, registers, a hard disk, a removable
disk, a CD-ROM, or any other form of computer-readable storage
medium known in the art. A sample storage medium may be coupled to
a machine such as, for example, a computer/processor (which may be
referred to herein, for convenience, as a "processor") such the
processor can read information (e.g., code) from and write
information to the storage medium. A sample storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in user equipment. In the
alternative, the processor and the storage medium may reside as
discrete components in user equipment. Moreover, in some aspects
any suitable computer-program product may comprise a
computer-readable medium comprising codes relating to one or more
of the aspects of the disclosure. In some aspects a computer
program product may comprise packaging materials.
[0067] While the invention has been described in connection with
various aspects, it will be understood that the invention is
capable of further modifications. This application is intended to
cover any variations, uses or adaptation of the invention
following, in general, the principles of the invention, and
including such departures from the present disclosure as come
within the known and customary practice within the art to which the
invention pertains.
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