U.S. patent application number 13/047557 was filed with the patent office on 2011-09-29 for method and system for uplink acknowledgement signaling in carrier-aggregated wireless communication systems.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Joonyoung Cho, Young-Han Nam, Jianzhong Zhang.
Application Number | 20110235599 13/047557 |
Document ID | / |
Family ID | 44656422 |
Filed Date | 2011-09-29 |
United States Patent
Application |
20110235599 |
Kind Code |
A1 |
Nam; Young-Han ; et
al. |
September 29, 2011 |
METHOD AND SYSTEM FOR UPLINK ACKNOWLEDGEMENT SIGNALING IN
CARRIER-AGGREGATED WIRELESS COMMUNICATION SYSTEMS
Abstract
A base station includes a transmit path circuitry to transmit DL
grant, data streams, and a control signal to configure a number of
uplink transmit antenna ports PUCCH to a subscriber station. The
base station also includes a receive path circuitry to receive
ACK/NACK modulation in response to the data streams. If the
subscriber station is configured to transmit ACK/NACK using one
uplink transmit antenna port and channel selection with PUCCH
format 1B, a modulation symbol is transmitted on one (PUCCH) i
determined based at least partly upon a channel selection mapping
table. If the subscriber station is configured to transmit ACK/NACK
using two uplink transmit antenna ports and channel selection with
PUCCH format 1B, the ACK/NACK modulation symbol is transmitted on
two PUCCHs.
Inventors: |
Nam; Young-Han; (Richardson,
TX) ; Zhang; Jianzhong; (Irving, TX) ; Cho;
Joonyoung; (Suwon-si, KR) |
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
44656422 |
Appl. No.: |
13/047557 |
Filed: |
March 14, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61318703 |
Mar 29, 2010 |
|
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|
61384081 |
Sep 17, 2010 |
|
|
|
61434345 |
Jan 19, 2011 |
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04W 72/0413 20130101;
H04W 72/02 20130101; H04L 1/1854 20130101; H04L 5/0055 20130101;
H04L 5/0053 20130101; H04L 5/0023 20130101; H04L 5/001 20130101;
H04L 1/0027 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 72/04 20090101
H04W072/04 |
Claims
1. A base station comprising: a transmit path circuitry configured
to transmit a downlink (DL) grant, data streams, and a control
signal to configure a number of uplink transmit antenna ports for
physical uplink control channel (PUCCH) to a subscriber station;
and a receive path circuitry configured to receive
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams, wherein if the
subscriber station is configured by the base station to transmit
ACK/NACK using one uplink transmit antenna port and channel
selection with PUCCH format 1B, a modulation symbol is transmitted
on one physical uplink control channel (PUCCH) i determined based
at least partly upon a channel selection mapping table, and wherein
if the subscriber station is configured by the base station to
transmit ACK/NACK using two uplink transmit antenna ports and
channel selection with PUCCH format 1B, the ACK/NACK modulation
symbol is transmitted on two PUCCHs, and wherein a first channel of
the two PUCCHs is PUCCH i determined based at least partly upon the
channel selection mapping table and a second channel of the two
PUCCHs is determined implicitly by a function depending on at least
one of i, L, and M, where L is a number of uplink control channels
allocated for the subscriber station's ACK/NACK, and M is a number
of ACK/NACK bits conveyed in a transmission in a subframe.
2. The base station of claim 1, wherein the second channel is
determined using (i+1)mod L.
3. The base station of claim 1, wherein L is determined using the
following table: TABLE-US-00001 Number of Number of allocated
Number of ACK/NACK allocated uplink uplink control symbols that
would be control channels channels when conveyed in a transmission
when SORTD is SORTD is in a single subframe, M NOT configured,
L.sub.0 configured, L 1 1 2 2 2 3 3 3 3 4 4 4 5 X X
4. The base station of claim 1, wherein the second channel is
determined using (i+M)mod L.
5. The base station of claim 1, wherein L is determined using the
following table: TABLE-US-00002 Number of Number of ACK/NACK
symbols allocated uplink Number of allocated that would be conveyed
control channels uplink control channels in a transmission in a
when SORTD is when SORTD is single subframe, M NOT configured,
L.sub.0 configured, L 1 1 2 2 2 4 3 3 6 4 4 8 5 X 2X
6. A method of operating a base station, the method comprising:
transmitting a downlink (DL) grant, data streams, and a control
signal to configure a number of uplink transmit antenna ports for
physical uplink control channel (PUCCH) to a subscriber station;
and receiving ACKnowledgement/Negative ACKnowledgement (ACK/NACK)
from the subscriber station in response to the data streams,
wherein if the subscriber station is configured by the base station
to transmit ACK/NACK using one uplink transmit antenna port and
channel selection with PUCCH format 1B, a modulation symbol is
transmitted on one physical uplink control channel (PUCCH) i
determined based at least partly upon a channel selection mapping
table, and wherein if the subscriber station is configured by the
base station to transmit ACK/NACK using two uplink transmit antenna
ports and channel selection with PUCCH format 1B, the ACK/NACK
modulation symbol is transmitted on two PUCCHs, and wherein a first
channel of the two PUCCHs is PUCCH i determined based at least
partly upon the channel selection mapping table and a second
channel of the two PUCCHs is determined implicitly by a function
depending on at least one of i, L, and M, where L is a number of
uplink control channels allocated for the subscriber station's
ACK/NACK, and M is a number of ACK/NACK bits conveyed in a
transmission in a subframe.
7. The method of claim 6, wherein the second channel is determined
using (i+1)mod L.
8. The method of claim 6, wherein L is determined using the
following table: TABLE-US-00003 Number of ACK/NACK Number of
allocated symbols that would be uplink control Number of conveyed
in a channels when allocated uplink transmission in a SORTD is NOT
control channels when single subframe, M configured, L.sub.0 SORTD
is configured, L 1 1 2 2 2 3 3 3 3 4 4 4 5 X X
9. The method of claim 6, wherein the second channel is determined
using (i+M)mod L.
10. The method of claim 6, wherein L is determined using the
following table: TABLE-US-00004 Number of Number of Number of
ACK/NACK symbols allocated uplink allocated uplink that would be
conveyed in a control channels control channels transmission in a
when SORTD when SORTD is single subframe, M is NOT configured,
L.sub.0 configured, L 1 1 2 2 2 4 3 3 6 4 4 8 5 X 2X
11. A subscriber station comprising: a receive path circuitry
configured to receive a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station; and a transmit path circuitry configured to transmit
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) to the base
station in response to the data streams, wherein if the subscriber
station is configured by the base station to transmit ACK/NACK
using one uplink transmit antenna port and channel selection with
PUCCH format 1B, a modulation symbol is transmitted on one physical
uplink control channel (PUCCH) i determined based at least partly
upon a channel selection mapping table, and wherein if the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the ACK/NACK modulation symbol is
transmitted on two PUCCHs, and wherein a first channel of the two
PUCCHs is PUCCH i determined based at least partly upon the channel
selection mapping table and a second channel of the two PUCCHs is
determined implicitly by a function depending on at least one of i,
L, and M, where L is a number of uplink control channels allocated
for the subscriber station's ACK/NACK, and M is a number of
ACK/NACK bits conveyed in a transmission in a subframe.
12. The subscriber station of claim 11, wherein the second channel
is determined using (i+1)mod L.
13. The subscriber station of claim 11, wherein L is determined
using the following table: TABLE-US-00005 Number of ACK/NACK Number
of allocated symbols that would be uplink control Number of
conveyed in a channels when allocated uplink transmission in a
SORTD is NOT control channels when single subframe, M configured,
L.sub.0 SORTD is configured, L 1 1 2 2 2 3 3 3 3 4 4 4 5 X X
14. The subscriber station of claim 11, wherein the second channel
is determined using (i+M)mod L.
15. The subscriber station of claim 11, wherein L is determined
using the following table: TABLE-US-00006 Number of Number of
Number of ACK/NACK symbols allocated uplink allocated uplink that
would be conveyed in a control channels control channels
transmission in a when SORTD when SORTD is single subframe, M is
NOT configured, L.sub.0 configured, L 1 1 2 2 2 4 3 3 6 4 4 8 5 X
2X
16. A method of operating a subscriber station, the method
comprising: receiving a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station; and transmitting ACKnowledgement/Negative ACKnowledgement
(ACK/NACK) to the base station in response to the data streams,
wherein if the subscriber station is configured by the base station
to transmit ACK/NACK using one uplink transmit antenna port and
channel selection with PUCCH format 1B, a modulation symbol is
transmitted on one physical uplink control channel (PUCCH) i
determined based at least partly upon a channel selection mapping
table, and wherein if the subscriber station is configured by the
base station to transmit ACK/NACK using two uplink transmit antenna
ports and channel selection with PUCCH format 1B, the ACK/NACK
modulation symbol is transmitted on two PUCCHs, and wherein a first
channel of the two PUCCHs is PUCCH i determined based at least
partly upon the channel selection mapping table and a second
channel of the two PUCCHs is determined implicitly by a function
depending on at least one of i, L, and M, where L is a number of
uplink control channels allocated for the subscriber station's
ACK/NACK, and M is a number of ACK/NACK bits conveyed in a
transmission in a subframe.
17. The method of claim 16, wherein the second channel is
determined using (i+1)mod L.
18. The method of claim 16, wherein L is determined using the
following table: TABLE-US-00007 Number of ACK/NACK Number of
allocated symbols that would be uplink control Number of conveyed
in a channels when allocated uplink transmission in a SORTD is NOT
control channels when single subframe, M configured, L.sub.0 SORTD
is configured, L 1 1 2 2 2 3 3 3 3 4 4 4 5 X X
19. The method of claim 16, wherein the second channel is
determined using (i+M)mod L.
20. The method of claim 16, wherein L is determined using the
following table: TABLE-US-00008 Number of Number of Number of
ACK/NACK symbols allocated uplink allocated uplink that would be
conveyed in a control channels control channels transmission in a
when SORTD when SORTD is single subframe, M is NOT configured,
L.sub.0 configured, L 1 1 2 2 2 4 3 3 6 4 4 8 5 X 2X
21. A base station comprising: a transmit path circuitry configured
to transmit a downlink (DL) grant, data streams, and a control
signal to configure a number of uplink transmit antenna ports for
physical uplink control channel (PUCCH) to a subscriber station;
and a receive path circuitry configured to receive an
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams, wherein if the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the configuration of two uplink
transmit antenna ports is overridden and the modulation symbol is
mapped to only one PUCCH on one transmit antenna port, and wherein
if the subscriber station is configured by the base station to
transmit ACK/NACK using two uplink transmit antenna ports and PUCCH
format 1A/1B, the modulation symbol is mapped onto two uplink
transmit antenna ports on two PUCCHs.
22. A method of operating a base station, the method comprising:
transmitting a downlink (DL) grant, data streams, and a control
signal to configure a number of uplink transmit antenna ports for
physical uplink control channel (PUCCH) to a subscriber station;
and receiving an ACKnowledgement/Negative ACKnowledgement
(ACK/NACK) from the subscriber station in response to the data
streams, wherein if the subscriber station is configured by the
base station to transmit ACK/NACK using two uplink transmit antenna
ports and channel selection with PUCCH format 1B, the configuration
of two uplink transmit antenna ports is overridden and the
modulation symbol is mapped to only one PUCCH on one transmit
antenna port, and wherein if the subscriber station is configured
by the base station to transmit ACK/NACK using two uplink transmit
antenna ports and PUCCH format 1A/1B, the modulation symbol is
mapped onto two uplink transmit antenna ports on two PUCCHs.
23. A subscriber station comprising: a receive path circuitry
configured to receive a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station; and a transmit path circuitry configured to transmit an
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) to the base
station in response to the data streams, wherein if the subscriber
station is configured by the base station to transmit ACK/NACK
using two uplink transmit antenna ports and channel selection with
PUCCH format 1B, the configuration of two uplink transmit antenna
ports is overridden and the modulation symbol is mapped to only one
PUCCH on one transmit antenna port, and wherein if the subscriber
station is configured by the base station to transmit ACK/NACK
using two uplink transmit antenna ports and PUCCH format 1A/1B, the
modulation symbol is mapped onto two uplink transmit antenna ports
on two PUCCHs.
24. The subscriber station of claim 23, wherein if the subscriber
station is configured by the base station to transmit ACK/NACK
using two uplink transmit antenna ports and channel selection with
format 1B, then the modulation symbol is mapped onto one physical
uplink-control channel, the one PUCCH being transmitted on multiple
physical transmit antennas corresponding to one uplink transmit
antenna port.
25. A method of operating a subscriber station, the method
comprising: receiving a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station; and transmitting an ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) modulation symbol to the base station in
response to the data streams, wherein if the subscriber station is
configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and channel selection with PUCCH
format 1B, the configuration of two uplink transmit antenna ports
is overridden and the modulation symbol is mapped to only one PUCCH
on one transmit antenna port, and wherein if the subscriber station
is configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and PUCCH format 1A/1B, the
modulation symbol is mapped onto two uplink transmit antenna ports
on two PUCCHs.
26. The method of claim 25, wherein if the subscriber station is
configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and channel selection with format 1B,
then the modulation symbol is mapped onto one physical
uplink-control channel, the one PUCCH being transmitted on multiple
physical transmit antennas corresponding to one uplink transmit
antenna port.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY
[0001] The present application is related to U.S. Provisional
Patent Application No. 61/318,703, filed Mar. 29, 2010, entitled
"UL TRANSMIT DIVERSITY IN CARRIER-AGGREGATED WIRELESS COMMUNICATION
SYSTEMS", U.S. Provisional Patent Application No. 61/384,081, filed
Sep. 17, 2010, entitled "UPLINK TRANSMIT DIVERSITY IN WIRELESS
COMMUNICATION SYSTEMS" and U.S. Provisional Patent Application No.
61/434,345, filed Jan. 19, 2011, entitled "UL ACKNOWLEDGEMENT
SIGNALING IN CARRIER-AGGREGATED WIRELESS COMMUNICATION SYSTEMS".
Provisional Patent Application Nos. 61/318,703, 61/384,081 and
61/434,345 are assigned to the assignee of the present application
and are hereby incorporated by reference into the present
application as if fully set forth herein. The present application
hereby claims priority under 35 U.S.C. .sctn.119(e) to U.S.
Provisional Patent Application Nos. 61/318,703, 61/384,081 and
61/434,345.
TECHNICAL FIELD OF THE INVENTION
[0002] The present application relates generally to wireless
communications and, more specifically, to a method and system for
reference signal (RS) pattern design.
BACKGROUND OF THE INVENTION
[0003] In 3.sup.rd Generation Partnership Project Long Term
Evolution (3GPP LTE), Orthogonal Frequency Division Multiplexing
(OFDM) is adopted as a downlink (DL) transmission scheme.
SUMMARY OF THE INVENTION
[0004] A base station is provided. The base station includes a
transmit path circuitry configured to transmit a downlink (DL)
grant, data streams, and a control signal to configure a number of
uplink transmit antenna ports for physical uplink control channel
(PUCCH) to a subscriber station. The base station also includes a
receive path circuitry configured to receive
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams. If the
subscriber station is configured by the base station to transmit
ACK/NACK using one uplink transmit antenna port and channel
selection with PUCCH format 1B, a modulation symbol is transmitted
on one physical uplink control channel (PUCCH) i determined based
at least partly upon a channel selection mapping table. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the ACK/NACK modulation symbol is
transmitted on two PUCCHs. A first channel of the two PUCCHs is
PUCCH i determined based at least partly upon the channel selection
mapping table and a second channel of the two PUCCHs is determined
implicitly by a function depending on at least one of i, L, and M,
where L is a number of uplink control channels allocated for the
subscriber station's ACK/NACK, and M is a number of ACK/NACK bits
conveyed in a transmission in a subframe.
[0005] A method of operating a base station is provided. The method
includes transmitting a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) to a subscriber
station. The method also includes receiving
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams. If the
subscriber station is configured by the base station to transmit
ACK/NACK using one uplink transmit antenna port and channel
selection with PUCCH format 1B, a modulation symbol is transmitted
on one physical uplink control channel (PUCCH) i determined based
at least partly upon a channel selection mapping table. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the ACK/NACK modulation symbol is
transmitted on two PUCCHs. A first channel of the two PUCCHs is
PUCCH i determined based at least partly upon the channel selection
mapping table and a second channel of the two PUCCHs is determined
implicitly by a function depending on at least one of i, L, and M,
where L is a number of uplink control channels allocated for the
subscriber station's ACK/NACK, and M is a number of ACK/NACK bits
conveyed in a transmission in a subframe.
[0006] A subscriber station is provided. The subscriber station
includes a receive path circuitry configured to receive a downlink
(DL) grant, data streams, and a control signal to configure a
number of uplink transmit antenna ports for physical uplink control
channel (PUCCH) from a base station. The subscriber station also
includes a transmit path circuitry configured to transmit
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) to the base
station in response to the data streams. If the subscriber station
is configured by the base station to transmit ACK/NACK using one
uplink transmit antenna port and channel selection with PUCCH
format 1B, a modulation symbol is transmitted on one physical
uplink control channel (PUCCH) i determined based at least partly
upon a channel selection mapping table. If the subscriber station
is configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and channel selection with PUCCH
format 1B, the ACK/NACK modulation symbol is transmitted on two
PUCCHs. A first channel of the two PUCCHs is PUCCH i determined
based at least partly upon the channel selection mapping table and
a second channel of the two PUCCHs is determined implicitly by a
function depending on at least one of i, L, and M, where L is a
number of uplink control channels allocated for the subscriber
station's ACK/NACK, and M is a number of ACK/NACK bits conveyed in
a transmission in a subframe.
[0007] A method of operating a subscriber station is provided. The
method includes receiving a downlink (DL) grant, data streams, and
a control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station. The method includes transmitting ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) to the base station in response to the
data streams. If the subscriber station is configured by the base
station to transmit ACK/NACK using one uplink transmit antenna port
and channel selection with PUCCH format 1B, a modulation symbol is
transmitted on one physical uplink control channel (PUCCH) i
determined based at least partly upon a channel selection mapping
table. If the subscriber station is configured by the base station
to transmit ACK/NACK using two uplink transmit antenna ports and
channel selection with PUCCH format 1B, the ACK/NACK modulation
symbol is transmitted on two PUCCHs. A first channel of the two
PUCCHs is PUCCH i determined based at least partly upon the channel
selection mapping table and a second channel of the two PUCCHs is
determined implicitly by a function depending on at least one of i,
L, and M, where L is a number of uplink control channels allocated
for the subscriber station's ACK/NACK, and M is a number of
ACK/NACK bits conveyed in a transmission in a subframe.
[0008] A base station is provided. The base station includes a
transmit path circuitry configured to transmit a downlink (DL)
grant, data streams, and a control signal to configure a number of
uplink transmit antenna ports for physical uplink control channel
(PUCCH) to a subscriber station. The base station also includes a
receive path circuitry configured to receive an
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the configuration of two uplink
transmit antenna ports is overridden and the modulation symbol is
mapped to only one PUCCH on one transmit antenna port. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and PUCCH format
1A/1B, the modulation symbol is mapped onto two uplink transmit
antenna ports on two PUCCHs.
[0009] A method of operating a base station is provided. The method
includes transmitting a downlink (DL) grant, data streams, and a
control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) to a subscriber
station. The method also includes receiving an
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and channel
selection with PUCCH format 1B, the configuration of two uplink
transmit antenna ports is overridden and the modulation symbol is
mapped to only one PUCCH on one transmit antenna port. If the
subscriber station is configured by the base station to transmit
ACK/NACK using two uplink transmit antenna ports and PUCCH format
1A/1B, the modulation symbol is mapped onto two uplink transmit
antenna ports on two PUCCHs.
[0010] A subscriber station is provided. The subscriber station
includes a receive path circuitry configured to receive a downlink
(DL) grant, data streams, and a control signal to configure a
number of uplink transmit antenna ports for physical uplink control
channel (PUCCH) from a base station. The subscriber station also
includes a transmit path circuitry configured to transmit
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) to the base
station in response to the data streams. If the subscriber station
is configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and channel selection with PUCCH
format 1B, the configuration of two uplink transmit antenna ports
is overridden and the modulation symbol is mapped to only one PUCCH
on one transmit antenna port. If the subscriber station is
configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and PUCCH format 1A/1B, the
modulation symbol is mapped onto two uplink transmit antenna ports
on two PUCCHs.
[0011] A method of operating a subscriber station is provided. The
method includes receiving a downlink (DL) grant, data streams, and
a control signal to configure a number of uplink transmit antenna
ports for physical uplink control channel (PUCCH) from a base
station. The method includes transmitting ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) to the base station in response to the
data streams. If the subscriber station is configured by the base
station to transmit ACK/NACK using two uplink transmit antenna
ports and channel selection with PUCCH format 1B, the configuration
of two uplink transmit antenna ports is overridden and the
modulation symbol is mapped to only one PUCCH on one transmit
antenna port. If the subscriber station is configured by the base
station to transmit ACK/NACK using two uplink transmit antenna
ports and PUCCH format 1A/1B, the modulation symbol is mapped onto
two uplink transmit antenna ports on two PUCCHs.
[0012] Before undertaking the DETAILED DESCRIPTION OF THE INVENTION
below, it may be advantageous to set forth definitions of certain
words and phrases used throughout this patent document: the terms
"include" and "comprise," as well as derivatives thereof, mean
inclusion without limitation; the term "or," is inclusive, meaning
and/or; the phrases "associated with" and "associated therewith,"
as well as derivatives thereof, may mean to include, be included
within, interconnect with, contain, be contained within, connect to
or with, couple to or with, be communicable with, cooperate with,
interleave, juxtapose, be proximate to, be bound to or with, have,
have a property of, or the like; and the term "controller" means
any device, system or part thereof that controls at least one
operation, such a device may be implemented in hardware, firmware
or software, or some combination of at least two of the same. It
should be noted that the functionality associated with any
particular controller may be centralized or distributed, whether
locally or remotely. Definitions for certain words and phrases are
provided throughout this patent document, those of ordinary skill
in the art should understand that in many, if not most instances,
such definitions apply to prior, as well as future uses of such
defined words and phrases.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the present disclosure
and its advantages, reference is now made to the following
description taken in conjunction with the accompanying drawings, in
which like reference numerals represent like parts:
[0014] FIG. 1 illustrates an exemplary wireless network that
transmits messages in the uplink according to the principles of the
present disclosure;
[0015] FIG. 2 is a high-level diagram of an OFDMA transmitter
according to one embodiment of the disclosure;
[0016] FIG. 3 is a high-level diagram of an OFDMA receiver
according to one embodiment of the disclosure;
[0017] FIG. 4 illustrates a flow of messages between an enhanced
Node B (eNodeB) and a user equipment (UE) according to an
embodiment of this disclosure;
[0018] FIG. 5 illustrates Long Term Evolution (LTE) control channel
elements (CCEs) in a downlink (DL) carrier according to an
embodiment of this disclosure.
[0019] FIG. 6 illustrates a Physical Uplink Control CHannel (PUCCH)
resource partition in one resource block in an uplink (UL) carrier
in an LTE system according to an embodiment of this disclosure;
[0020] FIG. 7 illustrates an uplink control channel resource
allocation for a particular UE depending on whether Spatial
Orthogonal-Resource Transmit Diversity (SORTD) is configured or not
according to an embodiment of this disclosure;
[0021] FIG. 8 illustrates a table that indicates the number of
allocated uplink control channels when SORTD is configured
according to an embodiment of this disclosure;
[0022] FIG. 9 illustrates a table that indicates the number of
allocated uplink control channels when SORTD is configured
according to another embodiment of this disclosure;
[0023] FIG. 10 illustrates a table depicting modulation symbol d(0)
for Physical Uplink Control CHannel (PUCCH) formats 1a and 1b
according to an embodiment of this disclosure;
[0024] FIG. 11 illustrates a table by which the value b(0),b(1) and
the ACK/NACK resource n.sub.PUCCH.sup.(1) are generated by channel
selection for M=2 according to an embodiment of this
disclosure;
[0025] FIG. 12 illustrates a table by which the value b(0),b(1) and
the ACK/NACK resource n.sub.PUCCH.sup.(1) are generated by channel
selection for M=3 according to an embodiment of this
disclosure;
[0026] FIG. 13 illustrates a table by which the value b(0),b(1) and
the ACK/NACK resource n.sub.PUCCH.sup.(1) are generated by channel
selection for M=4 according to an embodiment of this
disclosure;
[0027] FIG. 14 illustrates an ACK/NACK mapping according to an
embodiment of this disclosure;
[0028] FIG. 15 illustrates an ACK/NACK mapping according to another
embodiment of this disclosure;
[0029] FIG. 16 illustrates an ACK/NACK mapping according to yet
another embodiment of this disclosure;
[0030] FIG. 17 illustrates an ACK/NACK mapping according to a
further embodiment of this disclosure
[0031] FIG. 18A is a table depicting information elements (IEs) for
Media Access Control component carrier (MAC CC) activation
signaling according to an embodiment of this disclosure;
[0032] FIG. 18B is a table depicting IEs for (MAC CC activation
signaling according to another embodiment of this disclosure;
[0033] FIG. 19 illustrates a HARQ-ACK message transmission when two
antennas are configured according to an embodiment of this
disclosure;
[0034] FIG. 20 illustrates a determination of a second set of
control channels for antenna port p.sub.1 according to an
embodiment of this disclosure;
[0035] FIG. 21 illustrates a determination of a second set of
control channels for antenna port p.sub.1 according to another
embodiment of this disclosure;
[0036] FIG. 22 illustrates a determination of a second set of
control channels for antenna port p.sub.1 according to a further
embodiment of this disclosure;
[0037] FIG. 23 illustrates data transmission over two antennas
using slot-based precoding vector switching (PVS) or time switched
transmit diversity (TSTD) according to an embodiment of this
disclosure;
[0038] FIG. 24 illustrates a method of ACK/NACK transmission at a
UE when ACK/NACK multiplexing is utilized according to an
embodiment of this disclosure;
[0039] FIG. 25 illustrates a method of ACK/NACK transmission at a
UE when ACK/NACK bundling is utilized according to an embodiment of
this disclosure;
[0040] FIG. 26 illustrates a method of selecting N CCEs for D-ACK
resource mapping according to an embodiment of this disclosure;
[0041] FIG. 27 illustrates a method of CCE resource reservation for
ACK/NACK transmissions according to an embodiment of this
disclosure;
[0042] FIG. 28 illustrates CCE to ACK/NACK mapping when only one
N.sub.PUCCH.sup.(1) index number is signaled according to an
embodiment of this disclosure;
[0043] FIG. 29 illustrates CCE to ACK/NACK mapping when two
N.sub.PUCCH.sup.(1) index numbers are signaled according to an
embodiment of this disclosure;
[0044] FIG. 30 illustrates a method of ACK/NACK multiplexing
according to an embodiment of this disclosure;
[0045] FIG. 31 illustrates a method of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to an embodiment of this disclosure;
[0046] FIG. 32 illustrates a method of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to another embodiment of this disclosure;
[0047] FIG. 33 illustrates a method of ACK/NACK multiplexing
according to another embodiment of this disclosure;
[0048] FIG. 34 illustrates a method of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to a further embodiment of this disclosure;
[0049] FIG. 35 illustrates a method of operating a base station
according to an embodiment of this disclosure;
[0050] FIG. 36 illustrates a method of operating a subscriber
station according to an embodiment of this disclosure;
[0051] FIG. 37 illustrates a method of operating a base station
according to another embodiment of this disclosure; and
[0052] FIG. 38 illustrates a method of operating a subscriber
station according to another embodiment of this disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0053] FIGS. 1 through 38, discussed below, and the various
embodiments used to describe the principles of the present
disclosure in this patent document are by way of illustration only
and should not be construed in any way to limit the scope of the
disclosure. Those skilled in the art will understand that the
principles of the present disclosure may be implemented in any
suitably arranged wireless communication system.
[0054] With regard to the following description, it is noted that
the LTE term "node B" is another term for "base station" used
below. Also, the LTE term "user equipment" or "UE" is another term
for "subscriber station" used below.
[0055] FIG. 1 illustrates exemplary wireless network 100, which
transmits messages according to the principles of the present
disclosure. In the illustrated embodiment, wireless network 100
includes base station (BS) 101, base station (BS) 102, base station
(BS) 103, and other similar base stations (not shown).
[0056] Base station 101 is in communication with Internet 130 or a
similar IP-based network (not shown).
[0057] Base station 102 provides wireless broadband access to
Internet 130 to a first plurality of subscriber stations within
coverage area 120 of base station 102. The first plurality of
subscriber stations includes subscriber station 111, which may be
located in a small business (SB), subscriber station 112, which may
be located in an enterprise (E), subscriber station 113, which may
be located in a WiFi hotspot (HS), subscriber station 114, which
may be located in a first residence (R), subscriber station 115,
which may be located in a second residence (R), and subscriber
station 116, which may be a mobile device (M), such as a cell
phone, a wireless laptop, a wireless PDA, or the like.
[0058] Base station 103 provides wireless broadband access to
Internet 130 to a second plurality of subscriber stations within
coverage area 125 of base station 103. The second plurality of
subscriber stations includes subscriber station 115 and subscriber
station 116. In an exemplary embodiment, base stations 101-103 may
communicate with each other and with subscriber stations 111-116
using OFDM or OFDMA techniques.
[0059] While only six subscriber stations are depicted in FIG. 1,
it is understood that wireless network 100 may provide wireless
broadband access to additional subscriber stations. It is noted
that subscriber station 115 and subscriber station 116 are located
on the edges of both coverage area 120 and coverage area 125.
Subscriber station 115 and subscriber station 116 each communicate
with both base station 102 and base station 103 and may be said to
be operating in handoff mode, as known to those of skill in the
art.
[0060] Subscriber stations 111-116 may access voice, data, video,
video conferencing, and/or other broadband services via Internet
130. In an exemplary embodiment, one or more of subscriber stations
111-116 may be associated with an access point (AP) of a WiFi WLAN.
Subscriber station 116 may be any of a number of mobile devices,
including a wireless-enabled laptop computer, personal data
assistant, notebook, handheld device, or other wireless-enabled
device. Subscriber stations 114 and 115 may be, for example, a
wireless-enabled personal computer (PC), a laptop computer, a
gateway, or another device.
[0061] FIG. 2 is a high-level diagram of an Orthogonal Frequency
Division Multiple Access (OFDMA) transmit path 200. FIG. 3 is a
high-level diagram of an OFDMA receive path 300. In FIGS. 2 and 3,
the OFDMA transmit path 200 is implemented in base station (BS) 102
and the OFDMA receive path 300 is implemented in subscriber station
(SS) 116 for the purposes of illustration and explanation only.
However, it will be understood by those skilled in the art that the
OFDMA receive path 300 may also be implemented in BS 102 and the
OFDMA transmit path 200 may be implemented in SS 116.
[0062] The transmit path 200 in BS 102 comprises a channel coding
and modulation block 205, a serial-to-parallel (S-to-P) block 210,
a Size N Inverse Fast Fourier Transform (IFFT) block 215, a
parallel-to-serial (P-to-S) block 220, an add cyclic prefix block
225, an up-converter (UC) 230, a reference signal multiplexer 290,
and a reference signal allocator 295.
[0063] The receive path 300 in SS 116 comprises a down-converter
(DC) 255, a remove cyclic prefix block 260, a serial-to-parallel
(S-to-P) block 265, a Size N Fast Fourier Transform (FFT) block
270, a parallel-to-serial (P-to-S) block 275, and a channel
decoding and demodulation block 280.
[0064] At least some of the components in FIGS. 2 and 3 may be
implemented in software while other components may be implemented
by configurable hardware or a mixture of software and configurable
hardware. In particular, it is noted that the FFT blocks and the
IFFT blocks described in the present disclosure document may be
implemented as configurable software algorithms, where the value of
Size N may be modified according to the implementation.
[0065] Furthermore, although the present disclosure is directed to
an embodiment that implements the Fast Fourier Transform and the
Inverse Fast Fourier Transform, this is by way of illustration only
and should not be construed to limit the scope of the disclosure.
It will be appreciated that in an alternate embodiment of the
disclosure, the Fast Fourier Transform functions and the Inverse
Fast Fourier Transform functions may easily be replaced by Discrete
Fourier Transform (DFT) functions and Inverse Discrete Fourier
Transform (IDFT) functions, respectively. It will be appreciated
that for DFT and IDFT functions, the value of the N variable may be
any integer number (i.e., 1, 2, 3, 4, etc.), while for FFT and IFFT
functions, the value of the N variable may be any integer number
that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).
[0066] In BS 102, channel coding and modulation block 205 receives
a set of information bits, applies coding (e.g., Turbo coding) and
modulates (e.g., Quadrature Phase Shift Keying (QPSK) or Quadrature
Amplitude Modulation (QAM)) the input bits to produce a sequence of
frequency-domain modulation symbols. Serial-to-parallel block 210
converts (i.e., de-multiplexes) the serial modulated symbols to
parallel data to produce N parallel symbol streams where N is the
IFFT/FFT size used in BS 102 and SS 116. Size N IFFT block 215 then
performs an IFFT operation on the N parallel symbol streams to
produce time-domain output signals. Parallel-to-serial block 220
converts (i.e., multiplexes) the parallel time-domain output
symbols from Size N IFFT block 215 to produce a serial time-domain
signal. Add cyclic prefix block 225 then inserts a cyclic prefix to
the time-domain signal. Finally, up-converter 230 modulates (i.e.,
up-converts) the output of add cyclic prefix block 225 to RF
frequency for transmission via a wireless channel. The signal may
also be filtered at baseband before conversion to RF frequency. In
some embodiments, reference signal multiplexer 290 is operable to
multiplex the reference signals using Code Division Multiplexing
(CDM) or Time/Frequency Division Multiplexing (TFDM). Reference
signal allocator 295 is operable to dynamically allocate reference
signals in an OFDM signal in accordance with the methods and system
disclosed in the present disclosure.
[0067] The transmitted RF signal arrives at SS 116 after passing
through the wireless channel and reverse operations performed at BS
102. Down-converter 255 down-converts the received signal to
baseband frequency and remove cyclic prefix block 260 removes the
cyclic prefix to produce the serial time-domain baseband signal.
Serial-to-parallel block 265 converts the time-domain baseband
signal to parallel time domain signals. Size N FFT block 270 then
performs an FFT algorithm to produce N parallel frequency-domain
signals. Parallel-to-serial block 275 converts the parallel
frequency-domain signals to a sequence of modulated data symbols.
Channel decoding and demodulation block 280 demodulates and then
decodes the modulated symbols to recover the original input data
stream.
[0068] Each of base stations 101-103 may implement a transmit path
that is analogous to transmitting in the downlink to subscriber
stations 111-116 and may implement a receive path that is analogous
to receiving in the uplink from subscriber stations 111-116.
Similarly, each one of subscriber stations 111-116 may implement a
transmit path corresponding to the architecture for transmitting in
the uplink to base stations 101-103 and may implement a receive
path corresponding to the architecture for receiving in the
downlink from base stations 101-103.
[0069] The total bandwidth in an OFDM system is divided into
narrowband frequency units called subcarriers. The number of
subcarriers is equal to the FFT/IFFT size N used in the system. In
general, the number of subcarriers used for data is less than N
because some subcarriers at the edge of the frequency spectrum are
reserved as guard subcarriers. In general, no information is
transmitted on guard subcarriers.
[0070] The time resources of an LTE system are partitioned into 10
msec frames, and each frame is further partitioned into 10
subframes of one msec duration each. A subframe is divided into two
time slots, each of which spans 0.5 msec. A subframe is partitioned
in the frequency domain into multiple resource blocks (RBs), where
an RB is composed of 12 subcarriers.
[0071] The transmitted signal in each downlink (DL) slot of a
resource block is described by a resource grid of
N.sub.RB.sup.DLN.sub.SC.sup.RB subcarriers and N.sub.symb.sup.DL
OFDM symbols. The quantity N.sub.RB.sup.DL depends on the downlink
transmission bandwidth configured in the cell and fulfills
N.sub.RB.sup.min,DL.ltoreq.N.sub.RB.sup.DL.ltoreq.N.sub.RB.sup.max,DL,
where N.sub.RB.sup.min,DL and N.sub.RB.sup.max,DL are the smallest
and largest downlink bandwidth, respectively, supported. In some
embodiments, subcarriers are considered the smallest elements that
are capable of being modulated.
[0072] In case of multi-antenna transmission, there is one resource
grid defined per antenna port.
[0073] Each element in the resource grid for antenna port p is
called a resource element (RE) and is uniquely identified by the
index pair (k, l) in a slot where k=0, . . . ,
N.sub.RB.sup.DLN.sub.SC.sup.RB-1 and l=0, . . . ,
N.sub.symb.sup.DL-1 are the indices in the frequency and time
domains, respectively. Resource element (k,l) on antenna port p
corresponds to the complex value a.sub.k,k.sup.(p). If there is no
risk for confusion or no particular antenna port is specified, the
index p may be dropped.
[0074] In LTE, DL reference signals (RSs) are used for two
purposes. First, UEs measure Channel Quality Information (CQI),
Rank Information (RI) and Precoder Matrix Information (PMI) using
DL RSs. Second, each UE demodulates the DL transmission signal
intended for itself using the DL RSs. In addition, DL RSs are
divided into three categories: cell-specific RSs, Multi-media
Broadcast over a Single Frequency Network (MBSFN) RSs, and
UE-specific RSs or dedicated RSs (DRSs).
[0075] Cell-specific reference signals (or common reference
signals: CRSs) are transmitted in all downlink subframes in a cell
supporting non-MBSFN transmission. If a subframe is used for
transmission with MBSFN, only the first a few (0, 1 or 2) OFDM
symbols in a subframe can be used for transmission of cell-specific
reference symbols. The notation R.sub.p is used to denote a
resource element used for reference signal transmission on antenna
port p.
[0076] UE-specific reference signals (or dedicated RS: DRS) are
supported for single-antenna-port transmission of Physical Downlink
Shared CHannel (PDSCH) and are transmitted on antenna port 5. The
UE is informed by higher layers whether the UE-specific reference
signal is present and is a valid phase reference for PDSCH
demodulation or not. UE-specific reference signals are transmitted
only on the resource blocks upon which the corresponding PDSCH is
mapped.
[0077] FIG. 4 illustrates a flow 400 of messages between an
enhanced Node B (eNodeB) and a user equipment (UE) according to an
embodiment of this disclosure.
[0078] As shown in FIG. 4, a DL transmission to a UE 410 is
scheduled and initiated by an eNodeB 420. For a DL transmission in
a subframe, the eNodeB 420 sends DL Control Information (DCI) to
the UE 410 in a Physical DL Control CHannel (PDCCH) located in the
first few OFDM symbols in the subframe (flow 401). The DCI
indicates the allocated RBs for the UE 410 and other information.
The eNodeB 420 also transmits a message to the UE 410 (flow 403).
Upon receiving a DL grant targeted to itself, the UE 410 attempts
to decode the transmitted message on the allocated RBs. Depending
on the decoding results, the UE 410 is expected to send Hybrid
Automatic Repeat reQuest (HARQ) bits (or uplink
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) bits) to the
eNodeB 410 in a later subframe (flow 405). For example, in a
Frequency-Division Duplex (FDD) system, ACK/NACK response in
subframe n is for the decoding result in subframe n-4.
[0079] There are multiple formats of DCI used for different
purposes. For example, one format is for downlink grant for a UE,
another format is for uplink grant for a UE, and another format is
for conveying common control information.
[0080] FIG. 5 illustrates Long Term Evolution (LTE) control channel
elements (CCEs) in a downlink (DL) carrier 500 according to an
embodiment of this disclosure.
[0081] A PDCCH that carries DCI is transmitted on an aggregation of
one or several consecutive control channel elements (CCEs). The
CCEs available in a DL carrier are numbered from 0 and N.sub.CCE-1.
FIG. 5 shows an illustration of CCE allocation, wherein CCEs 0
through 3 are used for a DL grant for UE 0; CCEs 6 to 7 are used
for a DL grant for UE 1; CCEs 4 and 5 are used for a common control
information for all UEs; and CCEs N.sub.CCE-2 and N.sub.CCE-1 are
used for an UL grant for UE 2.
[0082] FIG. 6 illustrates a Physical Uplink Control CHannel (PUCCH)
resource partition 600 in one resource block in an uplink (UL)
carrier in an LTE system according to an embodiment of this
disclosure.
[0083] In some embodiments, the uplink (UL) ACK/NACK (AN) bits are
transmitted on PUCCH formats 1a and 1b. Resources used for
transmission of PUCCH format 1a/1b are represented by the
non-negative index n.sub.PUCCH.sup.(1). PUCCH resource index
n.sub.PUCCH.sup.(1) determines an orthogonal cover (OC) and a
cyclic shift (CS), and these two parameters indicate a unique
resource. In the example shown in FIG. 6, there are 3.times.12=36
PUCCH AN resources available in a resource block.
[0084] As opposed to the LTE system which operates in a single
contiguous bandwidth (or in a single carrier), the next generation
communication systems (for example, LTE-Advanced and Worldwide
Interoperability for Microwave Access (WiMax)) allow for aggregated
multiple bandwidths and allow for a UE and an eNodeB to operate in
the resultant aggregated carriers. The bandwidth aggregation can be
symmetric or asymmetric. In the symmetric case, the number of
component carriers (CCs) in the UL and the DL are the same. In the
asymmetric case, the number of carriers in the UL and the DL can be
different.
[0085] For acknowledging on multiple PDSCHs (e.g., in multiple
subframes or in multiple DL component carriers (CCs)), two methods
are considered, ACK/NACK bundling and ACK/NACK multiplexing.
[0086] The main motivation behind ACK/NACK bundling is to reduce
the acknowledgement signaling overhead by reducing the number of
bits transmitted in the signaling. One way of reducing the number
of bits is to take a logical AND operation across the multiple
ACK/NACK bits corresponding to multiple PDSCHs for each codeword.
In a system where up to two codewords are allowed, this bundling
would result in two bits for the acknowledgement signal.
[0087] The main motivation behind ACK/NACK multiplexing is to feed
individual decoding results of PDSCHs back to an eNodeB. In some
embodiments, spatial bundling is applied, implying that a logical
AND operation is taken of ACK/NACK bits across codewords. As a
result of spatial bundling, there are M ACK/NACK bits for
acknowledging M PDSCHs, regardless of the number of codewords in
each PDSCH transmission. After applying spatial bundling, a channel
selection method is used for feeding multiple ACK/NACK bits back to
the eNodeB. When a channel selection method is used for ACK/NACK
multiplexing, both a selected PUCCH resource and a modulation
symbol carried in the selected PUCCH resource convey information on
multiple ACK/NACK bits. In particular, a UE transmits signals in
only n PUCCH resources out of the N PUCCH resources, where n is a
natural number less than or equal to M. Typical example values for
n are 1 and 2. The M-bit information is jointly conveyed by the
identity of the n selected channels (or PUCCH resources) and the
signals transmitted in each of the n selected channels. In one
example, when M=3-bit ACK/NACK information needs to be conveyed
from a UE to an eNodeB, at least 8 (=2.sup.M=2.sup.3) codepoints
are needed. By utilizing (n=1) channel selection out of (M=3) PUCCH
resources, the identity of a selected PUCCH resource provides 3
codepoints. Furthermore, when a selected channel (or PUCCH
resource) carries a QPSK signal, a 2-bit information (or 4
codepoints) can be transmitted in each selected PUCCH resource. In
total, 12 (=3.times.12) codepoints are generated by this channel
selection method, and 8 out of these 12 codepoints can be used to
carry the 8 states associated with the 3 ACK/NACK bits.
[0088] In some cases, a UE is equipped with multiple transmit
antennas, and is configured by an eNodeB to perform PUCCH transmit
diversity. When the UE is scheduled a DL data (PDSCH) transmission
in a subframe in only one DL CC by a DL grant, corresponding
dynamic ACK/NACK are transmitted in a later subframe using two
PUCCH resources in one UL CC, where the two PUCCH resources carry
the identical signals for the ACK/NACK. Furthermore, the two PUCCH
resources are transmitted on two uplink transmit antenna ports.
This method of PUCCH transmit diversity is also known as Orthogonal
Resource Transmission, or ORT (or spatial orthogonal resource
transmission diversity, SORTD).
[0089] In an embodiment of this disclosure, M, the number of
ACK/NACK symbols that would be conveyed in a transmission in a
subframe, is determined by at least one of the following
parameters: (1) the number of configured DL CCs, or N, (2) the
number of activated DL CCs and (3) the number of DL CCs that have
received PDSCHs in a previous subframe for which the UE sends an
acknowledgement message in a current subframe. In some particular
embodiments, M is determined from at least one of the three
parameters listed below:
[0090] M is equal to the number of configured DL CCs, or N;
[0091] M is equal to the number of activated DL CCs; and
[0092] M is equal to the number of DL CCs that have received PDSCHs
in a previous subframe for which the UE sends an acknowledgement
message in a current subframe.
[0093] In an embodiment of this disclosure, for a UE configured
with Spatial Orthogonal-Resource Transmit Diversity (SORTD), the
number of allocated uplink control channels for the UE's
acknowledgement for M DL CCs, denoted by L, is determined by a
function of at least one of M and L.sub.0. Here, L.sub.0 denotes a
number of uplink control channels allocated for the UE when SORTD
is not configured. In particular embodiment, L.gtoreq.L.sub.0 as
this allows more channels to select from in case SORTD is
configured. Furthermore, the L channels for the UE when SORTD is
configured include the L.sub.0 channels for the UE when SORTD is
NOT configured. Here, an uplink control channel (or resource) is
defined by a pair of a cyclic shift (CS) and an orthogonal cover
code (OCC) located in an uplink physical resource block (UL PRE) as
in Rel-8 LTE.
[0094] FIG. 7 illustrates an uplink control channel resource
allocation 700 for a particular UE depending on whether Spatial
Orthogonal-Resource Transmit Diversity (SORTD) is configured or not
according to an embodiment of this disclosure.
[0095] In the embodiment shown in FIG. 7, L.sub.0=2 and L=3. When
SORTD is configured, channels 0, 1 and 2 are allocated for UE 0.
When SORTD is not configured, only channels 0 and 1 are allocated
for UE 0.
[0096] FIG. 8 illustrates a table 800 that indicates the number of
allocated uplink control channels when SORTD is configured
according to an embodiment of this disclosure.
[0097] As shown in table 500, for M=5, it is assumed that X uplink
control channels are allocated for acknowledgement signaling of a
UE configured not to do SORTD, where X is an integer. For example,
X=8. It is noted that an L value in table 500 is a minimum number
satisfying the following conditions:
[0098] Condition 1: L.ltoreq.2 (i.e., there are at least two
channels to do SORTD), and
[0099] Condition 2: There are at least M possibilities to choose
two circularly consecutive channels out of L channels. In
particular embodiments, two channels are circularly consecutive if
the two channel indices are consecutive, or the two channel indices
are 0 and L-1, when the L channels are indexed with L consecutive
integers, 0,1,2, . . . L-1.
[0100] FIG. 9 illustrates a table 900 that indicates the number of
allocated uplink control channels when SORTD is configured
according to another embodiment of this disclosure.
[0101] Another example function is shown in table 900, where the
function is L=2M=2 L.sub.0. In table 900, for M=5, it is assumed
that X uplink control channels are allocated for acknowledgement
signaling of a UE not configured to perform SORTD, where X is an
integer.
[0102] In embodiments of this disclosure, a UE configured to
perform SORTD and configured to transmit M ACK/NACK symbols in a
subframe transmits one modulation symbol in two uplink control
channels out of L (where L.ltoreq.M) allocated channels, where one
uplink control channel is transmitted via one uplink antenna port,
and the other uplink control channel is transmitted via another
uplink antenna port (i.e., SORTD is implemented in the two selected
channels). In a particular embodiment, for example, an uplink
control channel is defined by a pair of a cyclic shift (CS) and an
orthogonal cover code (OCC) located in an uplink physical resource
block (UL PRB) as in Rel-8 LTE. The two channels for SORTD are
selected by a rule, where the rule is defined by extending an
ACK/NACK channel selection method for single-antenna transmissions.
On the other hand, the modulation symbol transmitted in the two
channels is identical to the modulation symbol transmitted in the
ACK/NACK channel selection method for single-antenna
transmissions.
[0103] For illustration of some example rules, the L channels are
first indexed in an ascending order in ACK/NACK resource numbers:
the lowest numbered channel in ACK/NACK resource numbers would be
channel 0, the second lowest numbered channel in ACK/NACK resource
numbers would be channel 1, and so on. An ACK/NACK message is then
considered that can be conveyed by a selected channel i out of M
channels, where i=0,1, . . . M-1, and a QPSK symbol q transmitted
in the selected channel, according to an ACK/NACK channel selection
method with SORTD NOT being configured.
[0104] In one example rule, the two selected channels are i and
(i+1)mod L.
[0105] In another example rule, the two selected channels are i and
(i+M)mod L.
[0106] In another example rule, the two selected channels are i and
(i-1)mod L.
[0107] Here, L channels can be allocated to a UE.
[0108] For Time-Division Duplex (TDD) ACK/NACK multiplexing and a
subframe n with M>1, where M is the number of elements in the
set K, spatial ACK/NACK bundling across multiple codewords within a
DL subframe is performed by a logical AND operation of all the
corresponding individual ACK/NACKs, and PUCCH format 1b with
channel selection is used. For TDD ACK/NACK multiplexing and a
subframe n with M=1, spatial ACK/NACK bundling across multiple
codewords within a DL subframe is not performed, 1 or 2 ACK/NACK
bits are transmitted using PUCCH format la or PUCCH format 1b,
respectively.
[0109] FIG. 10 illustrates a table 1000 depicting modulation symbol
d(0) for Physical Uplink Control CHannel (PUCCH) formats 1a and 1b
according to an embodiment of this disclosure.
[0110] According to table 1000, a UE transmits b(0),b(1) on an
ACK/NACK resource n.sub.PUCCH.sup.(1) in sub-frame n using PUCCH
format 1b.
[0111] FIG. 11 illustrates a table 1100 by which the value
b(0),b(1) and the ACK/NACK resource n.sub.PUCCH.sup.(1) are
generated by channel selection for M=2 according to an embodiment
of this disclosure.
[0112] FIG. 12 illustrates a table 1200 by which the value
b(0),b(1) and the ACK/NACK resource n.sub.PUCCH.sup.(1) are
generated by channel selection for M=3 according to an embodiment
of this disclosure.
[0113] FIG. 13 illustrates a table 1300 by which the value
b(0),b(1) and the ACK/NACK resource n.sub.PUCCH.sup.(1) are
generated by channel selection for M=4 according to an embodiment
of this disclosure.
[0114] FIG. 14 illustrates an ACK/NACK mapping 1400 according to an
embodiment of this disclosure.
[0115] FIG. 14 illustrates an example of mapping an ACK/NACK
message to selected channel(s) and a modulation symbol. In this
particular embodiment, M=2 and L is 3 according to table 800, and
two channels i and (i+1)mod L are selected using table 1100. As
indicated by table 1100, when ACK,ACK is multiplexed, the first
channel i is n.sub.PUCCH,1.sup.(1) and the second channel is
(1+1)mod3 or n.sub.PUCCH,2.sup.(1). When NACK,NACK/DTX is
multiplexed, the first channel i is n.sub.PUCCH,0.sup.(1) and the
second channel is (0+1)mod3 or n.sub.PUCCH,1.sup.(1).
[0116] FIG. 15 illustrates an ACK/NACK mapping 1500 according to
another embodiment of this disclosure.
[0117] FIG. 15 illustrates an example of mapping an ACK/NACK
message to selected channel(s) and a modulation symbol. In this
particular embodiment, M=3 and L is 3 according to table 800, and
two channels i and (i+1)mod L are selected using table 1200. As
indicated by table 1200, when ACK,ACK,ACK is multiplexed, the first
channel i is n.sub.PUCCH,2.sup.(1) and the second channel is
(2+1)mod3 or n.sub.PUCCH,0.sup.(1). When NACK,NACK/DTX,NACK/DTX is
multiplexed, the first channel i is n.sub.PUCCH,0.sup.(1) and the
second channel is (0+1)mod3 or n.sub.PUCCH,1.sup.(1).
[0118] FIG. 16 illustrates an ACK/NACK mapping 1600 according to
yet another embodiment of this disclosure.
[0119] FIG. 16 shows an embodiment of mapping an ACK/NACK message
to selected channel(s) and a modulation symbol when M=2 and L is 4
according to table 900. Two channels i and (i+M)mod L are selected
using table 1100. As indicated by table 1100, when ACK,ACK is
multiplexed, the first channel i is n.sub.PUCCH,1.sup.(1) and the
second channel is (1+2)mod4 or n.sub.PUCCH,3.sup.(1). When
NACK,NACK/DTX is multiplexed, the first channel i is
n.sub.PUCCH,0.sup.(1) and the second channel is (0+2)mod4 or
n.sub.PUCCH,2.sup.(1).
[0120] FIG. 17 illustrates an ACK/NACK mapping 1700 according to a
further embodiment of this disclosure.
[0121] In this particular embodiment, M=3 and L is 6 according to
table 900, and two channels i and (i+M)mod L are selected using
table 1200. As indicated by table 1200, when ACK,ACK,ACK is
multiplexed, the first channel i is n.sub.PUCCH,2.sup.(1) and the
second channel is (2+3)mod6 or n.sub.PUCCH,5.sup.(1). When
NACK,NACK/DTX,NACK/DTX is multiplexed, the first channel i is
n.sub.PUCCH.sup.(1) and the second channel is (0+3)mod6 or
n.sub.PUCCH,3.sup.(1).
[0122] In some embodiments of this disclosure, L uplink control
resources for ACK/NACK signal transmissions are allocated to each
UE by an eNodeB using a semi-static allocation method. The eNodeB
transmits an information element about one uplink resource index,
n.sub.PUCCH, in a higher-layer signaling. Each of the L resource
indices are then derived from a function of at least one of the one
uplink resource index n.sub.PUCCH, a separately signalled component
carrier (CC)-common resource offset N.sub.PUCCH.sup.(1) and L.
[0123] In some embodiments, when M CCs are activated for the UE,
the L number is derived by a relation between M and L, where some
example relations are shown in table 800 and table 900.
[0124] In some embodiments, the higher-layer signaling is a Radio
Resource Control component carrier (RRC CC) configuration signaling
to the UE: Upon-receiving the one uplink resource index, the UE
finds L consecutive uplink control resources starting from the one
uplink resource index n.sub.PUCCH, for the L uplink control
resources for ACK/NACK signal transmissions. In a particular
embodiment, each of the L index numbers for the PUCCH ACK/NACK
resources are determined by Equation 1 below:
n.sub.PUCCH,l.sup.(1)=n.sub.PUCCH+N.sub.PUCCH.sup.(1)+N.sub.offset,l,
l=1,2, . . . L, [Eqn. 1],
[0125] where N.sub.offset,l=l-1. For example, when L=4, the one
signalled uplink resource index is used for determining L=4
resources.
[0126] In some embodiments, the higher-layer signaling is a Media
Access Control (MAC) component carrier (CC) activation signaling to
the UE. For ease of description, it is assumed that the UE is
configured by an RRC CC configuration signaling to receive PDSCHs
from K CCs, where K.ltoreq.5. In addition, it is assumed that
M.sub.1 CCs are activated in subframe n-1. Via the MAC CC
activation signaling transmitted in subframe n, an M number of CCs
out of K configured CCs are activated for the UE in several
subframes after subframe n.
[0127] FIG. 18A is a table 1800 depicting information elements
(IEs) for Media Access Control component carrier (MAC CC)
activation signaling according to an embodiment of this
disclosure.
[0128] In a particular embodiment of the MAC CC activation
signaling, the eNodeB also indicates the identities of CCs that
will be activated by the MAC CC activation signaling, where the IEs
for this MAC CC activation signaling are listed in table 1800. This
can be done by a 5-bit bitmap information element (IE), where the
k-th element indicates whether the k-th CC out of the K configured
CCs is activated or not. For example, when k-th entry in the K-bit
bitmap is one, the k-th CC is activated; on the other hand, when
k-th entry in the 5 bit bitmap is zero, the k-th CC is
de-activated. In this case, M number would be the same as the
number of entries having one in the K-bit bitmap. Once the UE
successfully decodes the MAC CC activation signaling, the UE finds
L consecutive uplink control resources starting from the one uplink
resource index n.sub.PUCCH. In this case, each of the L index
numbers for the PUCCH ACK/NACK resources are determined by Equation
2 below:
n.sub.PUCCH,l.sup.(1)=n.sub.PUCCH+N.sub.PUCCH.sup.(1)+N.sub.offset,l,
l=1,2, . . . L, Eqn. 2],
[0129] where N.sub.offset,l=l-1. For example, when L=4, the one
signalled uplink resource index n.sub.PUCCH is used for determining
L=4 resources.
[0130] FIG. 18B is a table 1810 depicting IEs for (MAC CC
activation signaling according to another embodiment of this
disclosure.
[0131] In another embodiment of the MAC CC activation signaling,
the eNodeB also indicates an identity of one CC that will be
activated by the MAC CC activation signaling, where IEs for this
MAC CC activation signaling are listed in table 1810. This can be
done by a 2-bit information element (IE), in which each state from
the 2-bit field activates a CC according to table 1810. In this
case, M number would be equal to M.sub.1+1. Once the UE
successfully decodes the MAC CC activation signaling, the UE finds
additional consecutive uplink control resources using the one
uplink resource index n.sub.PUCCH. When it is assumed that the UE
has been allocated L.sub.1 uplink control resources for the M.sub.1
activated CCs, the additional L-L.sub.1 index numbers for the PUCCH
ACK/NACK resources newly allocated by the MAC activation signaling
are determined by Equation 3 below:
n.sub.PUCCH,l.sup.(1)=n.sub.PUCCH+N.sub.PUCCH.sup.(1)+N.sub.offset,l,
l=1,2, . . . L-L.sub.1, [Eqn. 3]
[0132] where N.sub.offset,l=l-1. For example, when L=4 and
L.sub.1=2, the one signalled uplink resource index n.sub.PUCCH is
used for determining 2 (=L-L.sub.1) additional resources.
[0133] In some embodiments of this disclosure, when M.sub.2 CCs are
deactivated out of M allocated CCs (M.sub.2.ltoreq.M), L.sub.2
uplink control resources are de-allocated from L previously
allocated uplink control resources.
[0134] In one embodiment, L.sub.2 largest-numbered uplink control
resources out of L previously allocated uplink control resources
are released (or de-allocated).
[0135] In another example method, L.sub.2 smallest-numbered uplink
control resources out of L previously allocated uplink control
resources are released (or de-allocated).
[0136] In embodiments of this disclosure, a UE determines up to A
uplink control channels for each Tx antenna port to convey an A-bit
HARQ-ACK message using a channel selection scheme. Here, an uplink
control channel (or resource) is defined by at least one of a
cyclic shift (CS) and an orthogonal cover code (OCC) located in an
uplink physical resource block (UL PRB), for example, PUCCH format
1a/1b in Rel-8 LTE.
[0137] The A uplink control channels for a first antenna port
p.sub.0 are denoted by n.sub.PUCCH,i.sup.(1, p=p.sup.0.sup.), i=0,
. . . , A-1.
[0138] The A uplink control channels for a second antenna port
p.sub.1 are denoted by n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.), i=0, .
. . , A-1.
[0139] A UE is configured to transmit HARQ-ACK using channel
selection on two antenna ports (or configured to do SORTD). In
order for the UE to transmit a HARQ-ACK message mapped to a
selected channel i and a QPSK symbol q on the selected channel
according to a mapping table (e.g., table 1100, table 1200 and
table 1300), the UE selects channel i from the A uplink control
channels determined for each antenna port, and transmits a QPSK
symbol q on each antenna port.
[0140] FIG. 19 illustrates a HARQ-ACK message transmission 1900
when two antennas are configured according to an embodiment of this
disclosure.
[0141] As shown in FIG. 19, a UE determines two resources for each
antenna port: ch0(0)=n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.) and
ch0(1)=n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.) for antenna port
p.sub.0, and ch1(0)=n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.) and
ch1(1)=n.sub.PUCCH,1.sup.(1,p=p.sup.1.sup.) for antenna port
p.sub.1. In a particular embodiment, it is assumed that the UE
transmits a HARQ-ACK message (ACK,ACK) according to the mapping in
table 1100. As a HARQ-ACK message (ACK,ACK) is mapped onto a
transmission of a QPSK symbol q=-1 on the second channel in table
1100, the UE transmits q=-1 on the two channels: ch0(1) on antenna
port p.sub.0 and ch1(1) on antenna port p.sub.1.
[0142] In embodiments of this disclosure, a UE is configured to
receive from a primary cell (or PCC) and a secondary cell (or SCC).
The transmission modes configured for the PCC and SCC are such that
up to N.sub.1 and N.sub.2 TBs can be transmitted in the PCC and in
the SCC, respectively. The UE then reports A (=N.sub.1+N.sub.2)
HARQ-ACK bits using a channel selection scheme in each subframe
where the UE is scheduled a HARQ-ACK transmission. In a particular
embodiment, N.sub.1, N.sub.2 .epsilon. {1, 2}.
[0143] In this case, the A uplink control channels to be used for a
channel selection scheme on each antenna port can be found as
follows:
[0144] 1. A (=N.sub.1+N.sub.2) uplink control channels to be used
by the first Tx antenna port p=p.sub.0,
{n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.)}, are found by the UE as
follows:
[0145] For a PDSCH transmission indicated by the detection of a
corresponding PDCCH in subframe n-4 on the primary cell, or for a
PDCCH indicating downlink SPS release in subframe n-4 on the
primary cell, the PUCCH resources are determined as follows:
[0146] When the PDSCH transmission is on the primary cell,
n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.)+n.sub.CCE+i+N.sub.PUCCH.sup.(1),
where i .epsilon. {0, . . . , N.sub.1-1},
[0147] where n.sub.CCE is the smallest CCE number used for the l)
transmission of the corresponding DCI assignment and
N.sub.PUCCH.sup.(1) is configured by higher layers.
[0148] When the PDSCH transmission is on the secondary cell,
n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.)=n.sub.CCE+i-N.sub.1+N.sub.PUCCH.sup-
.(1), where i .epsilon. {N.sub.1, . . . , A-1},
[0149] where n.sub.CCE is the smallest CCE number used for the
transmission of the corresponding DCI assignment and
N.sub.PUCCH.sup.(1) is configured by higher layers.
[0150] For a PDSCH transmission indicated by the detection of a
corresponding PDCCH in subframe n-4 on the secondary cell, the
value of n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.) is determined
according to higher layer configuration, where i .epsilon.
{N.sub.1, . . . , A-1}.
[0151] 2. A (=N.sub.1+N.sub.2) uplink control channels to be used
by the second Tx antenna port p=p.sub.1,
{n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.) are found by the UE as a
function of at least one of n.sub.CCE, N.sub.PUCCH.sup.(1),
{n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.)} and A.
[0152] Below are some example functions determining the
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.) from at least one of
n.sub.CCE, N.sub.PUCCH.sup.(1),
{n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.)} and A:
[0153] Example function 1: n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.) is
an offset larger than n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.). In
other words,
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.-
)+n.sub.offset, .A-inverted.i.
[0154] Here, n.sub.offset is a positive integer. In one example,
n.sub.offset=1. In another example, n.sub.offset=2.
[0155] FIG. 20 illustrates a determination 2000 of a second set of
control channels for antenna port p.sub.1 according to an
embodiment of this disclosure.
[0156] In the embodiment shown in FIG. 20, n.sub.offset=1. For
example, when uplink control channels 10, 11, 15 and 16 are
determined for antenna port p.sub.0, then uplink control channels
11, 12, 16 and 17 are determined for antenna port p.sub.1. In this
case, the uplink control channels that the eNodeB has to monitor to
decode a HARQ-ACK message are 10, 11, 12, 15, 16 and 17. In other
words, the eNodeB has to assign 6 uplink control channels for the
UE.
[0157] Example function 2: The i-th channel
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.) for the second Tx antenna is
the same as the (i+n.sub.offset mod A)-th channel for the first
antenna. In other words,
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,(i+n.sub.offset.sub.)mo-
d A.sup.(1,p=p.sup.0.sup.), .A-inverted.i.
[0158] Example function 3: For A>2, the i-th channel
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.) for the second Tx antenna is
the same as the (i+n.sub.offset mod A)-th channel for the first
antenna. In other words,
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,(i+n.sub.offset.sub.)mo-
d A.sup.(1,p=p.sup.0.sup.), .A-inverted.i, A>2.
[0159] On the other hand, for A=2, the first channel for the second
Tx antenna is determined by
n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.)-
, while the second channel for the second Tx antenna is determined
by
n.sub.PUCCH,1.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.)-
+n.sub.offset. Here, n.sub.offset is a positive integer. In one
example, n.sub.offset=1. In another example, n.sub.offset=2.
[0160] If
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,(i+n.sub.offset-
.sub.)mod A.sup.(1,p=p.sup.0.sup.), .A-inverted.i are applied for
A=2,
n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.)
and
n.sub.PUCCH,1.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,0.sup.(1,p=p.sup.0.s-
up.). Suppose that a QPSK symbol q sent on
n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.) and the same QPSK symbol q
sent on n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.) mean two different
HARQ-ACK messages. Then, according to
n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.)
and
n.sub.PUCCH,1.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,0.sup.(1,p=p.sup.0.s-
up.), the two different HARQ-ACK ACK messages are transmitted
identically, and q is sent on two channels
n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.) and
n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.). To avoid this situation, a
non-overlapping control channel is assigned for the second Tx
antenna, i.e.,
n.sub.PUCCH,1.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,1.sup.(1,p=p.sup.0-
.sup.)+n.sub.offset.
[0161] FIG. 21 illustrates a determination 2100 of a second set of
control channels for antenna port p.sub.1 according to another
embodiment of this disclosure.
[0162] In FIG. 21, n.sub.offset=1. For example, when uplink control
channels 10, 11, 15 and 16 are determined for antenna port p.sub.0,
then uplink control channels 10, 11, 15 and 16 are determined for
antenna port p.sub.1. In this case, the uplink control channels
that the eNodeB has to monitor to decode a HARQ-ACK message are 10,
11, 15 and 16. In other words, the eNodeB has to assign 4 uplink
control channels for the UE.
[0163] This method may or may not be applicable depending on
whether the control channels for antenna port p.sub.0
n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.), . . . ,
n.sub.PUCCH,A.sup.(1,p=p.sup.0.sup.) are dynamically allocated or
semi-statically allocated. When the control channels for antenna
port p.sub.0 are semi-statically allocated, the UE knows all the A
channels for antenna port p.sub.0 in any of the subframes the UE
transmits HARQ-ACK. Hence, the UE can always apply the cyclic-shift
operation illustrated in FIG. 21 to determine the channels for
antenna port p.sub.1 n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.), . . . ,
n.sub.PUCCH,A.sup.(1,p=p.sup.1.sup.). However, when the control
channels for antenna port p.sub.0 are dynamically allocated, e.g.,
by the CCE number of a corresponding PDCCH, the UE sometimes does
not know some of those control channels when the UE does not
successfully decode at least one downlink grant. For example,
suppose that the eNodeB transmits 2 DL grants, but the UE misses
the second DL grant. If it is further assumed that the UE is
configured with Single Input Multiple Output (SIMO) modes in both
the PCC and the SCC, then the UE knows
n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.) but does not know
n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.). According to this embodiment,
in this case, the UE cannot determine
n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.) as the UE does not know
n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.). To resolve this issue, the
next example function (denoted as example function 4) is
considered.
[0164] Example function 4: The channels for the second antenna port
are determined based on the HARQ-ACK payload in a HARQ-ACK
message.
[0165] When A=4, the other channels for the second antenna port are
determined based on Equation 4 below:
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,(i+n.sub.offset.sub.)mo-
d A.sup.(1,p=p.sup.0.sup.), .A-inverted.i. [Eqn. 4]
[0166] When A=3, one additional channel is determined for the
second antenna port, where the additional channel is located next
to a channel for the first antenna port determined for a cell with
1-TB transmission mode. The other channels for the second antenna
port are determined based on Equation 4.
[0167] When N.sub.1=1 and N.sub.2=2 (A=3),
n.sub.PUCCH,0.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.-
)+n.sub.offset.
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,(n.sub.offset.sub.+1)mo-
d A.sup.(1,p=p.sup.0.sup.), i .epsilon. {1,2}.
[0168] When N.sub.1=2 and N.sub.2=1 (A=3),
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,i+1.sup.(1,p=p.sup.0.su-
p.), i .epsilon. {0,1}.
n.sub.PUCCH,2.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,2.sup.(1,p=p.sup.0.sup.-
)+1.
[0169] When A=2, two additional channels are determined for the
second antenna port, where each of the two additional channels is
located next to a channel for the first antenna port determined for
each cell:
n.sub.PUCCH,i.sup.(1,p=p.sup.1.sup.)=n.sub.PUCCH,i.sup.(1,p=p.sup.0.sup.-
)+1, i .epsilon. {0,1}.
[0170] FIG. 22 illustrates a determination 2200 of a second set of
control channels for antenna port p.sub.1 according to a further
embodiment of this disclosure.
[0171] In FIG. 22, n.sub.offset=1. For example, when uplink control
channels 10, 11 and 15 are determined for antenna port p.sub.0,
then uplink control channels 11, 15 and 16 are determined for
antenna port p.sub.1. Again in this case, the uplink control
channels that the eNodeB has to monitor to decode a HARQ-ACK
message are 10, 11, 15, 16. In other words, eNodeB has to assign 4
uplink control channels for the UE.
[0172] The embodiment of FIG. 22 assumes a fallback-friendly
mapping characterized as follows:
[0173] A DL grant dynamically determines two uplink control
channels for the first antenna port, or, antenna port p.sub.0. For
example, a DL grant scheduling a PDSCH on the PCC determines two
control channels n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.) and
n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.), and a DL grant scheduling a
PDSCH on the SCC determines two control channels
n.sub.PUCCH,2.sup.(1,p=p.sup.0.sup.) and
n.sub.PUCCH,3.sup.(1,p=p.sup.0.sup.).
[0174] Each HARQ-ACK message associated with a single DL grant
reception (e.g., (ACK,ACK,DTX/NACK,DTX/NACK)) is mapped to a QPSK
symbol on the first control channel on the first antenna port,
e.g., n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.). For example, a HARQ-ACK
state (ACK,ACK,DTX/NACK,DTX/NACK) is mapped onto a transmission of
a QPSK symbol q.sub.0 on n.sub.PUCCH,0.sup.(1,p=p.sup.0.sup.).
[0175] Each HARQ-ACK message associated with both DL grant
reception (e.g., (ACK,ACK,ACK,ACK)) is mapped to a QPSK symbol on
the second control channel on the first antenna port, e.g.,
n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.).
[0176] Under the set of assumptions listed above, this embodiment
ensures that the UE can find a control channel to be used by the
second antenna port, even when the eNodeB transmits two DL grants
but the UE misses one out of the two. This can be seen in the
following:
[0177] A channel to convey a HARQ-ACK message associated with a
single DL grant reception scheduling PDSCH on the PCC on the second
antenna is equal to n.sub.PUCCH,1.sup.(1,p=p.sup.0.sup.). Even if
the UE misses a DL grant scheduling PDSCH on the SCC, the UE can
still transmit a corresponding HARQ-ACK message on the second
antenna port.
[0178] A channel to convey a HARQ-ACK message associated with a
single DL grant reception scheduling PDSCH on the SCC on the second
antenna is equal to n.sub.PUCCH,3.sup.(1,p=p.sup.0.sup.). Even if
the UE misses the DL grant scheduling PDSCH on the PCC, the UE can
still transmit a corresponding HARQ-ACK message on the second
antenna port.
[0179] In some embodiments of this disclosure, when the C number of
configured component carriers (or cells) is greater than 2, then
the UE uses spatial bundling (logical AND operation to construct
one bit out of up to two bits) to reduce the total number of
HARQ-ACK bits to be reduced to be C, and use Rel-8 channel
selection mapping (i.e., table 1100, table 1200 and table 1300)
with M=C. On the other hand, when the C number of configured
component carriers is 2, then the UE transmits A=N.sub.1+N.sub.2
number of HARQ-ACK bits (where N.sub.1 and N.sub.2 are the numbers
of TBs in the PCC and the SCC, respectively) and uses another
channel selection mapping optimized for two-cell DL
transmission.
[0180] As two-cell aggregation is expected to be the most
frequently configured in practice, it would be better to optimize
the HARQ-ACK transmission for the two-cell aggregation so that a UE
can report a variable number of HARQ-ACK bits, depending on the
configured transmission modes in the two cells. However, a set of
channel selection tables optimized for two-cell aggregation does
not ensure a good tradeoff between performance and UE complexity.
Hence, a simpler channel selection rule, e.g., Rel-8 channel
selection mapping with spatial bundling, is applied when the number
of configured component carriers is greater than 2.
[0181] FIG. 23 illustrates data transmission over two antennas
using slot-based precoding vector switching (PVS) or time switched
transmit diversity (TSTD) according to an embodiment of this
disclosure.
[0182] As shown in FIG. 23, in some cases, a UE utilizes a
specification-transparent transmit diversity scheme to transmit a
dynamic ACK/NACK modulation symbol in a single PUCCH resource which
is mapped by the one control channel element (CCE). One of ordinary
skill in the art would recognize that when
specification-transparent uplink transmit diversity scheme is used,
the eNodeB receiver assumes that the UE does not transmit signals
using transmit diversity. Therefore, the eNodeB receiver treats the
signals received from the UE as coming from a single uplink
transmit antenna port. The ACK/NACK modulation symbol is
multiplexed with the same CS and OC mapping to one CCE, and then
the data are transmitted over two antennas using slot-based
precoding vector switching (PVS) or time switched transmit
diversity (TSTD), which preserves single-carrier (SC) property and
employs one orthogonal resource for DMRS and control data.
[0183] When carrier aggregation is implemented, a UE may receive
data signals (or PDSCHs) from a number of DL component carriers
(CCs). In order for an eNodeB to inform a UE of a downlink resource
assignment in a subframe, the eNodeB sends the UE at least one
downlink transmission grant.
[0184] Implementations of carrier aggregation, which could be
either symmetric or asymmetric carrier aggregation, are considered
in this disclosure. In a subframe, an eNodeB assigns a number of DL
CCs, say N DL CCs, to a UE, through which the eNodeB transmits data
signals to the UE. In some embodiments, the eNodeB sends N DL
grants to the UE in the N DL CCs, one DL grant in each of these DL
CCs. In other embodiments, the eNodeB sends N DL grants to the UE
in only one DL CC, where these DL grants may have a
carrier-indicator field, which indicate a CC that a DL grant
schedules a PDSCH in. It is noted that a DL grant can be
alternatively be referred to as a PDCCH (physical downlink control
channel), PDCCH grant, or a downlink control information (DCI)
assignment.
[0185] Furthermore, a DL anchor CC and an UL anchor CC can be
configured in a UE-specific way or in a cell-specific way. The DL
anchor CC for a UE is a DL CC that carries a DL grant for the UE in
all the subframes in which the UE receives data signals. In other
words, when the UE receives at least one DL grant in a subframe,
the DL anchor CC will carry a DL grant for the UE. The one UL
anchor CC for a UE is an UL CC that carries uplink control
information for a UE, such as dynamic ACK/NACKs that corresponds to
DL data transmissions in the N DL CCs in earlier subframes.
[0186] In embodiments of this disclosure, a UE's method of
transmitting acknowledgement signals depends on the number of DL
CCs that have carried PDCCH DL grants in a corresponding DL
subframe.
[0187] In a particular embodiment, acknowledgement signals are
transmitted as follows:
[0188] When only one DL CC (i.e., a DL anchor) carries a DL grant
for a UE, the UE transmits a corresponding ACK/NACK bits using the
LTE Rel-8 method of ACK/NACK transmission in FDD.
[0189] In particular, when the UE has more than one Tx antenna, the
UE uses a specification-transparent transmit diversity scheme to
transmit an ACK/NACK modulation symbol in a PUCCH D-ACK
resource.
[0190] When more than one DL CCs carry a DL grant for a UE, the UE
transmits corresponding ACK/NACK bits using ACK/NACK multiplexing
method by a channel selection method.
[0191] FIG. 24 illustrates a method 2400 of ACK/NACK transmission
at a UE when ACK/NACK multiplexing is utilized according to an
embodiment of this disclosure.
[0192] As shown in FIG. 24, method 2400 includes determining
whether more than one DL CC carry the PDSCHs (block 2401).
[0193] If the PDSCHs are transmitted in more than one DL CC, the N
number of DL CCs that carried the PDSCHs and the M number of CCEs
that carried a PDCCH DL grant in the DL anchor CC are determined
(block 2403). N number of CCEs for D-ACK resources mapping are
selected (block 2405). The N number of CCEs are mapped to N D-ACK
resources (block 2407). ACK/NACK multiplexing is performed by a
channel selection method utilizing the N D-ACK resources (block
2409). The modulation symbols are then mapped to the selected D-ACK
resources in the antenna ports (block 2411).
[0194] If the PDSCHs are transmitted in one DL CC, one or two CCEs
for D-ACK resources mapping are selected (block 2413). The one or
two CCEs are mapped to one or two D-ACK resources (block 2415). One
modulation symbol is selected for the D-ACK signal (block 2417).
The modulation symbol is then mapped to the one or two D-ACK
resources in the antenna port (block 2411).
[0195] In other embodiments, acknowledgement signals are
transmitted as follows:
[0196] When only one DL CC (i.e., a DL anchor) carries a DL grant
for a UE, the UE transmits corresponding ACK/NACK bits using the
LTE Rel-8 method of ACK/NACK transmission in FDD.
[0197] In particular, when the UE has more than one Tx antenna, the
UE uses a specification-transparent transmit diversity scheme to
transmit an ACK/NACK modulation symbol in a PUCCH D-ACK
resource.
[0198] When more than one DL CCs carry a DL grant for a UE, the UE
transmits corresponding ACK/NACK bits using an ACK/NACK bundling
method.
[0199] FIG. 25 illustrates a method 2500 of ACK/NACK transmission
at a UE when ACK/NACK bundling is utilized according to an
embodiment of this disclosure.
[0200] As shown in FIG. 25, method 2500 includes determining the N
number of DL CCs that carried the PDSCHs and the M number of CCEs
that carried a PDCCH DL grant in the DL anchor CC (block 2501). One
or two CCEs for D-ACK resources mapping are selected (block 2503).
The one or two CCEs are mapped to one or two D-ACK resources (block
2505). If N>1 (block 2507), ACK/NACK bundling is performed
(block 2509). One modulation symbol is selected for the D-ACK
signal (block 2511). The modulation symbol is then mapped to the
one or two D-ACK resources in the antenna port (block 2513).
[0201] In some embodiments of this disclosure, UL control resources
for a UE's dynamic ACK/NACKs which acknowledge on a corresponding
DL data transmission in N DL CCs are located in an UL anchor CC for
the UE. Furthermore, the UL control resources are determined by
CCEs that carry a DL grant in a DL anchor CC for the previous DL
data transmission for the UE. The size of the UL control resources
is the same as the number of DL CCs that have been used in the
previous DL data transmission, or N.
[0202] FIG. 26 illustrates a method 2600 of selecting N CCEs for
D-ACK resource mapping according to an embodiment of this
disclosure.
[0203] Some embodiments of this disclosure describe the selection
of N CCEs for D-ACK resource mapping, for example, the selection of
the N number of CCEs for D-ACK resources mapping at block 2405 of
FIG. 24.
[0204] As shown in FIG. 26, the selection of N CCEs for D-ACK
resource mapping includes determining whether N.ltoreq.M (block
2601). Depending on the M number of CCEs that carry the DL grant in
the DL anchor CC and the N number of PDSCHs, two different methods
are utilized for the selection of the N CCEs for D-ACK resource
mapping as illustrated in FIG. 26.
[0205] In some cases, the M number CCEs that carry the DL grant in
the DL anchor CC is larger than or equal to the number of DL CCs
used in the previous DL data transmission, or N. In these cases, N
CCEs out of the M CCEs are used for determining the UL control
resources for the UE's dynamic ACK/NACK (block 2603). In one
example, the N CCEs having the N smallest CCE index numbers out of
the M CCEs are used. In another example, the N CCEs having the N
largest CCE index numbers from the M CCEs are used.
[0206] In some embodiments, the M number of CCEs that carry the DL
grant in the DL anchor CC is smaller than the number of DL CCs used
in the previous DL data transmission, or N. In this case, all the M
CCEs are used for determining M UL control resources for the UE's
dynamic ACK/NACK. The remaining (N-M) UL control resources are
determined by (N-M) CCE numbers from the remaining CCE numbers
other than the M CCE numbers. There can be multiple methods of
choosing the (N-M) CCE numbers. CCEs corresponding to the (N-M) CCE
numbers are referred to as reserved CCEs (block 2605).
[0207] In some embodiments, the (N-M) CCE numbers are (N-M)
consecutive numbers starting from a number which is larger than the
largest CCE number among the M CCE numbers by 1. For example, when
N=4, M=2 and the M CCEs are CCEs 3 and 4, the (N-M) CCE numbers
used for determining the remaining UL control resources are 5 and
6.
[0208] In another method, the (N-M) CCE numbers are (N-M)
consecutive numbers chosen from CCE numbers of CCEs sharing a same
parent node in a CCE search space tree as the M aggregated CCEs
carrying the PDCCH or DL grant. One way of choosing the (N-M) CCE
numbers in this embodiment is to choose the largest-numbered CCEs
from those CCEs sharing the same parent node as the M aggregated
CCEs carrying the DL grant.
[0209] FIG. 27 illustrates a method 2700 of CCE resource
reservation for ACK/NACK transmissions according to an embodiment
of this disclosure.
[0210] As shown in FIG. 27, in a DL anchor, (M=4) CCEs, i.e., CCEs
5 through 8, carry a DL grant for a UE in a subframe. If the total
number of DL grants for the UE in the subframe is N=6, then (N-M=2)
CCEs need to be reserved for ACK/NACK mapping. CCEs sharing a same
parent node as CCEs 5 through 8 are CCEs 1 through 4, and the
largest two CCE numbers from 1 through 4 are 3 and 4. Hence, CCEs 3
and 4 are reserved for the UE's ACK/NACK transmissions. In another
embodiment, the smallest-numbered CCEs from those CCEs sharing the
same parent node are chosen as the Al aggregated CCEs carrying the
DL grant.
[0211] In some embodiments, only one set of dynamic ACK/NACK
resources is allocated in an UL CC, implying that the UEs will
receive one offset index N.sub.PUCCH.sup.(1) for a mapping rule of
CCE numbers to ACK/NACK resources. The offset index
N.sub.PUCCH.sup.(1) is configured by higher layers according to the
Rel-8 LTE specifications.
[0212] Some embodiments of this disclosure describe mapping of N
CCE numbers to D-ACK resources, for example in block 2407 of FIG.
24.
[0213] In some embodiments, the mapping the N CCE indices to N UL
ACK/NACK resources is described as follows:
[0214] for a dynamically scheduled physical downlink shared channel
(PDSCH) indicated by the detection of a corresponding PDCCH in
subframe n-4, N PUCCH ACK/NACK resources are assigned to a UE.
[0215] Each of the N index numbers for the PUCCH ACK/NACK resources
are determined by Equation 5 below:
n.sub.PUCCH,k.sup.(1)=n.sub.CCE,k+N.sub.PUCCH.sup.(1), k=1,2, . . .
N, [Eqn. 5]
[0216] where n.sub.CCE,k is the k-th index number of a CCE out of
the N CCEs selected from the M CCEs used for transmission of the
corresponding DCI assignment and max{N-M,0} reserved CCEs.
[0217] FIG. 28 illustrates CCE to ACK/NACK mapping 2800 when only
one N.sub.PUCCH.sup.(1) index number is signaled according to an
embodiment of this disclosure.
[0218] For example, as shown in FIG. 28, when CCEs 3, 4, 5 and 6
are the N=4 CCEs that will be used for ACK/NACK resource mapping
for a UE, the resultant PUCCH dynamic ACK/NACK resources will be
determined as illustrated in FIG. 28, where
.DELTA..sub.shift.sup.PUCCH=2.
[0219] If there are any reserved CCEs for a UE, the usage of the
reserved CCEs is restricted at the eNodeB. The reserved CCEs cannot
be used for DL grant for another UE, as doing so may result in
dynamic ACK/NACK resource collision. However, the reserved CCEs can
be used for other purposes, for example, UL grant, common control,
and so on.
[0220] In some embodiments, two sets of dynamic ACK/NACK resources
are allocated in an UL CC, implying that the UEs will receive two
offset indices N.sub.PUCCH,1.sup.(1) and N.sub.PUCCH,2.sup.(1) for
a mapping rule of CCE numbers to ACK/NACK resources. One offset
index N.sub.PUCCH,1.sup.(1) is equal a N.sub.PUCCH.sup.(1) which is
configured by higher layers according to the Rel-8 LTE
specifications. The other offset index N.sub.PUCCH,2.sup.(1) is
configured by higher layers for advanced users (e.g., Rel-10 LTE-A
UEs). Among N PUCCH ACK/NACK resources, one group of resources are
determined by N.sub.PUCCH,1.sup.(1) and a corresponding number of
CCE index numbers among the N CCE numbers. The other groups of
resources are determined by N.sub.PUCCH,2.sup.(1) and a
corresponding number of CCE index numbers.
[0221] This disclosure also describes other embodiments of mapping
of N CCE numbers to D-ACK resources, for example in block 2407 of
FIG. 24.
[0222] One embodiment of mapping the N CCE indices to N UL ACK/NACK
resources is described as follows:
[0223] for a dynamically scheduled physical downlink shared channel
(PDSCH) indicated by the detection of a corresponding PDCCH in
subframe n-4, N PUCCH ACK/NACK resources are assigned to a UE. One
index number for the PUCCH ACK/NACK resource is determined by
Equation 6 below:
n.sub.PUCCH,1.sup.(1)=n.sub.CCE,1+N.sub.PUCCH,1.sup.(1). [Eqn.
6]
[0224] Each of the remaining (N-1) index numbers for the PUCCH
ACK/NACK resources are determined by Equation 7 below:
n.sub.PUCCH,k.sup.(1)=n.sub.CCE,k+N.sub.PUCCH,2.sup.(1), k=2,3, . .
. N, [Eqn. 7]
[0225] where n.sub.CCE,k is the k-th index number of a CCE out of
the N CCEs selected from the M CCEs used for transmission of the
corresponding DCI assignment and max(N-M,0) reserved CCEs.
[0226] FIG. 29 illustrates CCE to ACK/NACK mapping 2900 when two
N.sub.PUCCH.sup.(1) index numbers are signaled according to an
embodiment of this disclosure.
[0227] For example, when CCEs 0, 1 and 2 are the N=3 CCEs that will
be used for ACK/NACK resource mapping for a UE, the resultant PUCCH
dynamic ACK/NACK resources will be determined as illustrated in
FIG. 29, where .DELTA..sub.shift.sup.PUCCH=2.
[0228] If there are any reserved CCEs for a UE, the usage of the
reserved CCEs is restricted at the eNodeB. The reserved CCEs cannot
be used for DL grant for another advanced UE (e.g., Rel-10 UE), as
doing so may result in dynamic ACK/NACK resource collision.
However, the reserved CCEs can be used for other purposes, for
example, DL grant for Rel-8 LTE UE, UL grant, common control, and
so on.
[0229] In some embodiments of this disclosure, for both cases with
one offset and with two offsets for dynamic ACK/NACK resources,
n.sub.CCE,k, or the k-th index number from the N CCE numbers,
k=1,2, . . . N, is described in one of the at least two ways listed
below.
[0230] In one embodiment, n.sub.CCE,k is the k-th smallest CCE
number out of the N CCE numbers.
[0231] In another embodiment, the first M PUCCH ACK/NACK resources
are determined by the M CCEs used for transmission of the
corresponding DCI assignment, and the rest (N-M) resources are
determined by the max{N-M,0} reserved CCEs. One example of this
embodiment is described as follows: when k.ltoreq.M, n.sub.CCE,k is
the k-th smallest CCE number from the M CCEs used for transmission
of the corresponding DCI assignment; on the other hand, when
k>M, n.sub.CCE,k is the (k-M)-th smallest CCE number from the
(N-M) reserved CCEs.
[0232] FIG. 30 illustrates a method 3000 of ACK/NACK multiplexing
according to an embodiment of this disclosure.
[0233] In some embodiments of this disclosure, a number of channels
(or D-ACK resources) and a number of modulation symbols used for
ACK/NACK multiplexing varies depending upon a number of
corresponding PDSCHs in DL CCs. Method 3000 includes determining
whether the number of N PDSCHs is greater than or equal to a
constant number A (block 3001). When the number of N PDSCHs is
smaller than the constant number A, one channel selection is used
for mapping N ACK/NACK bits to one selected D-ACK resource and one
modulation symbol (block 3003). On the other hand, when the number
of N PDSCHs is greater than or equal to A, two channel selection is
used for mapping N ACK/NACK bits to two selected D-ACK resources
and two modulation symbols (block 3005).
[0234] FIG. 31 illustrates a method 3100 of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to an embodiment of this disclosure.
[0235] Furthermore, when a UE is configured to perform ORT, the
modulation symbols are to be mapped to antenna ports as illustrated
in FIG. 31. Method 3100 includes determining whether N>1 (block
3101). When N=1, the UE maps one modulation symbol in one PUCCH
D-ACK resource to multiple antenna ports using ORT (block 3103).
When N>1, method 3100 includes determining whether N.gtoreq.A
(block 3105). If N<A, then the UE maps one modulation symbol in
one PUCCH D-ACK resource to multiple antenna ports using a
specification-transparent antenna port mapping (block 3107). If
N.gtoreq.A, the UE maps two modulation symbols in two PUCCH D-ACK
resources to multiple antenna ports (block 3109).
[0236] FIG. 32 illustrates a method 3200 of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to another embodiment of this disclosure.
[0237] In embodiments of this disclosure, it is assumed that one
(n=1) channel selection method is utilized and the UE is configured
to perform ORT. In this case, a modulation symbol mapping method
varies depending upon a number of corresponding PDSCHs in DL CCs.
Method 3200 includes determining whether the number of PDSCHs, N,
is more than one or whether ACK/NACK multiplexing is utilized
(block 3201). When the number of PDSCHs is more than one (or when
ACK/NACK multiplexing is utilized), the one modulation symbol is
mapped to one PUCCH D-ACK resource utilizing a
specification-transparent antenna port mapping (block 3203). When
the number of PDSCHs is precisely one, the one modulation symbol is
mapped to multiple PUCCH D-ACK resources using ORT (block 3205). In
some embodiments, N is the number of configured DL CCs.
[0238] FIG. 33 illustrates a method 3300 of ACK/NACK multiplexing
according to another embodiment of this disclosure.
[0239] In some embodiments of this disclosure, a number of N
modulation symbols used for ACK/NACK multiplexing varies depending
upon a number of corresponding PDSCHs in DL CCs. Method 3300
includes determining whether the number of N PDSCHs is greater than
or equal to a constant number A (block 3301). When the number of N
PDSCHs is smaller than the constant number A, two D-ACK resources
and one modulation symbol are selected for mapping N ACK/NACK bits
(block 3303). On the other hand, when the number of PDSCHs is
greater than or equal to the constant number A, two D-ACK resources
and two modulation symbols are selected for mapping N ACK/NACK bits
(block 3305).
[0240] FIG. 34 illustrates a method 3400 of a mapping of modulation
symbol(s) to selected D-ACK resource(s) in antenna port(s)
according to a further embodiment of this disclosure.
[0241] When a UE is configured to perform ORT, the modulation
symbols are to be mapped to antenna ports as illustrated in FIG.
34. Method 3400 includes determining whether the number of N PDSCHs
is greater than or equal to a constant number A (block 3401). In
particular, when N<A, the UE maps one modulation symbol to
multiple antenna ports using ORT (block 3403). When N.gtoreq.A, the
UE maps two modulation symbols in two PUCCH D-ACK resources in two
transmit antennas (block 3405).
[0242] In embodiments of this disclosure, at least a DL anchor CC
carries a DL grant having codepoints indicating the total number of
DL grants transmitted in non-anchor DL CCs for a UE in a subframe.
As the DL anchor CC carries a DL grant for a UE when there is at
least one DL grant for the UE, one state for the signaling of the
total number of DL grants in a subframe can be saved.
[0243] Particular embodiments relate to cases in which only a DL
anchor CC carries those codepoints. In non-anchor CCs, when an
eNodeB decides to transmit data to a UE using a DL transmission
scheme, say DL transmission scheme X, the eNodeB transmits a DL
grant of a DCI format, say DCI format Y, to the UE in a subframe.
On the other hand, in the anchor CC for the UE, when the eNodeB
decides to transmit data to the UE using DL transmission scheme X,
the eNodeB transmits a DL grant of a DCI format slightly different
from DCI format Y to the UE in the subframe, in a sense that the
DCI format used in the DL anchor CC has codepoints used for
indicating the total number of DL grants transmitted in non-anchor
CC in the same subframe.
[0244] The codepoints in a DL grant in the anchor CC that indicate
the total number of DL grants transmitted in non-anchor DL CCs can
be provided by an additional field in DCI format Y. In some cases,
the additional field could be identical to the carrier indicator
field. The number of bits assigned to the additional field is a
cell-specific constant, e.g., 2 or 3 bits, or a UE-specific number
that may depend on the number of configured CCs for a UE. For
example, when a number of configured DL CCs for a UE is N=3, the
number of non-anchor DL CCs is 2, and
log.sub.2(N-1)=log.sub.2(3-1)=1 bit is assigned, where (N-1) is the
number of non-anchor DL CCs. Particular examples of DCI format Y
include DL grant DCI formats 1, 1A, 2A, 2B, etc., defined in an LTE
specification (Rel-8, Rel-9 and Rel-10).
[0245] Such embodiments are useful for the detection of
discontinuous transmission, also known as DTX. Cases where a DL
grant is missed at a UE are referred to as DTX. When DTX occurs as
a UE does not know that an eNodeB has transmitted a DL grant, a
corresponding ACK/NACK cannot be fed back to the eNodeB. When only
one CC is configured in FDD system, a DTX is detected at the eNodeB
by detecting ACK/NACK signals from the UE at an associated ACK/NACK
resource with the DL grant. However, in case where multiple CCs are
configured and ACK/NACK multiplexing based on a channel selection
is utilized, DTX may not be successfully detected at the eNodeB if
at least one DL grant is missed at the UE. As the total number of
DL CCs is signalled, DTX can be detected if at least one DL grant
is successfully detected at a UE.
[0246] FIG. 35 illustrates a method 3500 of operating a base
station according to an embodiment of this disclosure.
[0247] As show in FIG. 35, method 3500 includes transmitting a
downlink (DL) grant, data streams, and a control signal to
configure a number of uplink transmit antenna ports for physical
uplink control channel (PUCCH) to a subscriber station (block
3501). Method 3500 also includes receiving ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) from the subscriber station in response
to the data streams (block 3503). If the subscriber station is
configured by the base station to transmit ACK/NACK using one
uplink transmit antenna port and channel selection with PUCCH
format 1B, a modulation symbol is transmitted on one physical
uplink control channel (PUCCH) i determined based at least partly
upon a channel selection mapping table. If the subscriber station
is configured by the base station to transmit ACK/NACK using two
uplink transmit antenna ports and channel selection with PUCCH
format 1B, the ACK/NACK modulation symbol is transmitted on two
PUCCHs. A first channel of the two PUCCHs is PUCCH i determined
based at least partly upon the channel selection mapping table and
a second channel of the two PUCCHs is determined implicitly by a
function depending on at least one of i, L, and M, where L is a
number of uplink control channels allocated for the subscriber
station's ACK/NACK, and M is a number of ACK/NACK bits conveyed in
a transmission in a subframe.
[0248] FIG. 36 illustrates a method 3600 of operating a subscriber
station according to an embodiment of this disclosure.
[0249] As show in FIG. 36, method 3600 includes receiving a
downlink (DL) grant, data streams, and a control signal to
configure a number of uplink transmit antenna ports for physical
uplink control channel (PUCCH) from a base station (block 3601).
The method includes transmitting ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) to the base station in response to the
data streams (block 3603). If the subscriber station is configured
by the base station to transmit ACK/NACK using one uplink transmit
antenna port and channel selection with PUCCH format 1B, a
modulation symbol is transmitted on one physical uplink control
channel (PUCCH) i determined based at least partly upon a channel
selection mapping table. If the subscriber station is configured by
the base station to transmit ACK/NACK using two uplink transmit
antenna ports and channel selection with PUCCH format 1B, the
ACK/NACK modulation symbol is transmitted on two PUCCHs. A first
channel of the two PUCCHs is PUCCH i determined based at least
partly upon the channel selection mapping table and a second
channel of the two PUCCHs is determined implicitly by a function
depending on at least one of i, L, and M, where L is a number of
uplink control channels allocated for the subscriber station's
ACK/NACK, and M is a number of ACK/NACK bits conveyed in a
transmission in a subframe.
[0250] FIG. 37 illustrates a method 3700 of operating a base
station according to another embodiment of this disclosure.
[0251] As show in FIG. 37, method 3700 includes transmitting a
downlink (DL) grant, data streams, and a control signal to
configure a number of uplink transmit antenna ports for physical
uplink control channel (PUCCH) to a subscriber station (block
3701). The method also includes receiving an
ACKnowledgement/Negative ACKnowledgement (ACK/NACK) from the
subscriber station in response to the data streams (block 3703). If
the subscriber station is configured by the base station to
transmit ACK/NACK using two uplink transmit antenna ports and
channel selection with PUCCH format 1B, the configuration of two
uplink transmit antenna ports is overridden and the modulation
symbol is mapped to only one PUCCH on one transmit antenna port. If
the subscriber station is configured by the base station to
transmit ACK/NACK using two uplink transmit antenna ports and PUCCH
format 1A/1B, the modulation symbol is mapped onto two uplink
transmit antenna ports on two PUCCHs.
[0252] FIG. 38 illustrates a method 3800 of operating a subscriber
station according to another embodiment of this disclosure.
[0253] As show in FIG. 38, method 3800 includes receiving a
downlink (DL) grant, data streams, and a control signal to
configure a number of uplink transmit antenna ports for physical
uplink control channel (PUCCH) from a base station (block 3801).
The method includes transmitting ACKnowledgement/Negative
ACKnowledgement (ACK/NACK) to the base station in response to the
data streams (block 3803). If the subscriber station is configured
by the base station to transmit ACK/NACK using two uplink transmit
antenna ports and channel selection with PUCCH format 1B, the
configuration of two uplink transmit antenna ports is overridden
and the modulation symbol is mapped to only one PUCCH on one
transmit antenna port. If the subscriber station is configured by
the base station to transmit ACK/NACK using two uplink transmit
antenna ports and PUCCH format 1A/1B, the modulation symbol is
mapped onto two uplink transmit antenna ports on two PUCCHs.
[0254] Although the present disclosure has been described with an
exemplary embodiment, various changes and modifications may be
suggested to one skilled in the art. It is intended that the
present disclosure encompass such changes and modifications as fall
within the scope of the appended claims.
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