U.S. patent application number 11/538547 was filed with the patent office on 2007-06-14 for method and system for providing control information for supporting high speed downlink and uplink.
This patent application is currently assigned to INTERDIGITAL TECHNOLOGY CORPORATION. Invention is credited to Arty Chandra, Stephen E. Terry.
Application Number | 20070133458 11/538547 |
Document ID | / |
Family ID | 37692492 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070133458 |
Kind Code |
A1 |
Chandra; Arty ; et
al. |
June 14, 2007 |
METHOD AND SYSTEM FOR PROVIDING CONTROL INFORMATION FOR SUPPORTING
HIGH SPEED DOWNLINK AND UPLINK
Abstract
A method and system for providing control information for
supporting high speed downlink and high speed uplink packet access
are disclosed. A Node-B assigns at least one downlink control
channel and at least one uplink control channel to a wireless
transmit/receive unit (WTRU). The downlink control channel and the
uplink control channel are provided to carry control information
for both the downlink and the uplink. Conventional control channels
for downlink and uplink are combined into a reduced set of control
channels for uplink and downlink. The Node-B and the WTRU
communicate control information via the downlink control channel
and the uplink control channel. The WTRU receives downlink data and
transmits uplink data, and the Node-B receives uplink data and
transmits downlink data based on the control information
transmitted via the downlink control channel and the uplink control
channel.
Inventors: |
Chandra; Arty; (Manhasset
Hills, NY) ; Terry; Stephen E.; (Northport,
NY) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.;DEPT. ICC
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
INTERDIGITAL TECHNOLOGY
CORPORATION
3411 Silverside Road, Concord Plaza Suite 105, Hagley
Building
Wilmington
DE
19810
|
Family ID: |
37692492 |
Appl. No.: |
11/538547 |
Filed: |
October 4, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60725064 |
Oct 7, 2005 |
|
|
|
Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04W 72/1278 20130101;
H04L 1/1671 20130101; H04L 5/0055 20130101; H04L 1/0025 20130101;
H04L 1/0026 20130101; H04W 72/0406 20130101; H04L 1/1812
20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04Q 7/00 20060101
H04Q007/00 |
Claims
1. In a wireless communication system including a wireless
transmit/receive unit (WTRU) and a Node-B, a method for providing
control information for supporting a high speed downlink and
uplink, the method comprising: the Node-B assigning at least one
downlink control channel to the WTRU to carry downlink control
information for both the downlink and the uplink transmissions; the
Node-B assigning at least one uplink control channel to the WTRU to
carry uplink control information for both the downlink and the
uplink transmissions; the Node-B and the WTRU communicating
downlink and uplink control information via the downlink control
channel and the uplink control channel, respectively; and the WTRU
performing at least one of receiving downlink data and transmitting
uplink data based on the downlink control information and the
uplink control information, respectively, and the Node-B performing
at least one of receiving uplink data and transmitting downlink
data based on the uplink control information and the downlink
control information, respectively.
2. The method of claim 1 wherein the downlink control information
and the uplink control information includes at least one of packet
decoding information, receive process information and feedback
information.
3. The method of claim 2 wherein the downlink control information
and the uplink control information further includes scheduling
information.
4. The method of claim 3 wherein the scheduling information
includes scheduling request information and scheduling response
information.
5. The method of claim 3 wherein the scheduling information is
multiplexed with at least one of the packet decoding information,
the receive process information and the feedback information.
6. The method of claim 3 wherein the downlink control channel
includes a primary downlink control channel and a secondary
downlink control channel.
7. The method of claim 6 wherein the primary downlink control
channel is a shared control channel by all WTRUs and the secondary
control channel is a dedicated control channel for at least one
WTRU.
8. The method of claim 6 wherein the scheduling information is
transmitted via the primary downlink control channel and the packet
decoding information, the receive process information and the
feedback information are transmitted via the secondary downlink
control channel.
9. The method of claim 3 wherein at least one of the packet
decoding information, the receive process information, the feedback
information and the scheduling information is piggybacked on a data
packet.
10. The method of claim 3 wherein the scheduling information is
provided every transmission time interval (TTI).
11. The method of claim 3 wherein the scheduling information is
provided on a need basis.
12. The method of claim 3 wherein the scheduling information
includes resource allocation and duration, the duration indicating
a period during which the resource allocation is effective.
13. The method of claim 4 wherein scheduling information sent by
the Node-B to the WTRU includes at least one of resource allocation
for a downlink data channel, resource allocation for an uplink data
channel, resource allocation for an uplink control channel and
timing adjustment information.
14. The method of claim 13 wherein the timing adjustment
information is transmitted via a separate packet.
15. The method of claim 2 wherein the packet decoding information
includes at last one of a modulation scheme, a coding rate and a
packet size.
16. The method of claim 2 wherein the receive process information
includes at last one of a hybrid automatic repeat request (H-ARQ)
process identity, a new data indication, a redundancy version, a
packet sequence number, and status information.
17. The method of claim 2 wherein the feedback information includes
at last one of an acknowledgement (ACK)/non-acknowledgement (NACK)
indication, a channel quality indicator (CQI), a packet sequence
number, a hybrid automatic repeat request (H-ARQ) process identity,
status information, a transmit diversity information and power
control information.
18. The method of claim 1 wherein the downlink control information
and the uplink control information are sent separately in separate
control channels.
19. The method of claim 1 wherein the downlink control information
and the uplink control information are sent via a single control
channel at the same time.
20. The method of claim 1 wherein the downlink control channel is
assigned to the WTRU only when there is an active data transfer for
the downlink and the uplink control channel is assigned to the WTRU
only when there is an active data transfer for the uplink.
21. The method of claim 1 wherein the downlink control channel is
assigned to the WTRU even though there is no active data transfer
for the downlink and the uplink control channel assigned to the
WTRU even though there is no active data transfer for the
uplink.
22. The method of claim 1 wherein at least one of the downlink
control channel and the uplink control channel is a shared
channel.
23. The method of claim 1 wherein at least one of the downlink
control channel and the uplink control channel is a dedicated
channel.
24. The method of claim 4 wherein the scheduling response
information sent by the Node-B includes resource allocation for
uplink transmission.
25. The method of claim 1 wherein the wireless communication system
is a time division duplex (TDD) system.
26. The method of claim 25 wherein the WTRU goes to sleep during a
time slot that is not assigned to the WTRU.
27. The method of claim 3 wherein the scheduling information sent
by the Node-B to the WTRU includes downlink resource allocation,
and uplink resource allocation is implicitly derived from the
downlink resource allocation.
28. The method of claim 3 wherein the uplink control channel
includes a primary uplink control channel and a secondary uplink
control channel.
29. The method of claim 28 wherein the scheduling information is
transmitted via the primary uplink control channel and the packet
decoding information, the receive process information and the
feedback information are transmitted via the secondary uplink
control channel.
30. The method of claim 1 wherein the downlink control channel
includes indication bits to identify the type of control
information.
31. The method of claim 30 wherein the indication bits identify
that the downlink control channel contains only downlink control
information.
32. The method of claim 30 wherein the indication bits identify
that the downlink control channel contains only uplink control
information.
33. The method of claim 30 wherein the indication bits identify
that the downlink control channel contains broadcast
information.
34. The method of claim 30 wherein the indication bits identify
that the downlink control channel contains multimedia
broadcast/multicast services (MBMS) control information.
35. The method of claim 30 wherein the indication bits identify
that the control channel contains persistent scheduling
information.
36. The method of claim 30 wherein the indication bits identify
that the control channel contains paging information.
37. A wireless communication system for providing control
information for supporting a high speed downlink and a high speed
uplink, the system comprising: a Node-B configured to assign at
least one downlink control channel and at least one uplink control
channel to a wireless transmit/receive unit (WTRU), the downlink
control channel being provided to carry downlink control
information for both the downlink and the uplink and the uplink
control channel being provided to carry uplink control information
for both the downlink and the uplink, send downlink control
information to the WTRU via the downlink control channel, and
perform at least one of receiving uplink data and transmitting
downlink data based on the uplink control information and the
downlink control information, respectively; and the WTRU configured
to send uplink control information to the Node-B via the uplink
control channel and perform at least one of receiving downlink data
and transmitting uplink data based on the downlink control
information and the uplink control information, respectively.
38. The system of claim 37 wherein the control information includes
at least one of packet decoding information, receive process
information and feedback information.
39. The system of claim 38 wherein the control information includes
scheduling information.
40. The system of claim 39 wherein the scheduling information
includes scheduling request information and scheduling response
information.
41. The system of claim 39 wherein the scheduling information is
multiplexed with at least one of the packet decoding information,
the receive process information and the feedback information.
42. The system of claim 39 wherein the downlink control channel
includes a primary downlink control channel and a secondary
downlink control channel.
43. The system of claim 42 wherein the primary downlink control
channel is a shared control channel by all WTRUs and the secondary
control channel is a dedicated control channel for at least one
WTRU.
44. The system of claim 43 wherein the scheduling information is
transmitted via the primary downlink control channel and the packet
decoding information, the receive process information and the
feedback information are transmitted via the secondary downlink
control channel.
45. The system of claim 39 wherein at least one of the packet
decoding information, the receive process information, the feedback
information and the scheduling information is piggybacked on a data
packet.
46. The system of claim 39 wherein the scheduling information is
provided every transmission time interval (TTI).
47. The system of claim 39 wherein the scheduling information is
provided on a need basis.
48. The system of claim 39 wherein the scheduling information
includes resource allocation and duration, the duration indicating
a period during which the resource allocation is effective.
49. The system of claim 39 wherein the scheduling response
information sent by the Node-B to the WTRU includes at least one of
resource allocation for a downlink data channel, resource
allocation for an uplink data channel, resource allocation for an
uplink control channel and timing adjustment information.
50. The system of claim 49 wherein the timing adjustment
information is transmitted via a separate packet.
51. The system of claim 37 wherein the packet decoding information
includes at last one of a modulation scheme, a coding rate and a
packet size.
52. The system of claim 37 wherein the receive process information
includes at last one of a hybrid automatic repeat request (H-ARQ)
process identity, a new data indication, a redundancy version, a
packet sequence number, and status information.
53. The system of claim 37 wherein the feedback information
includes at last one of an acknowledgement
(ACK)/non-acknowledgement (NACK) indication, a channel quality
indicator (CQI), a packet sequence number, a hybrid automatic
repeat request (H-ARQ) process identity, status information, a
transmit diversity information and power control information.
54. The system of claim 37 wherein the downlink control information
and the uplink control information are sent separately over
separate control channels.
55. The system of claim 37 wherein the downlink control information
and the uplink control information are sent via a single control
channel at the same time.
56. The system of claim 37 wherein the downlink control channel is
assigned to the WTRU only when there is an active data transfer for
the downlink, and the uplink control channel is assigned to the
WTRU only when there is an active data transfer for the uplink.
57. The system of claim 37 wherein the downlink control channel is
assigned to the WTRU even though there is no active data transfer
for the downlink and the uplink control channel is assigned to the
WTRU even though there is no active data transfer for the
uplink.
58. The system of claim 37 wherein at least one of the downlink
control channel and the uplink control channel is a shared
channel.
59. The system of claim 37 wherein at least one of the downlink
control channel and the uplink control channel is a dedicated
channel.
60. The system of claim 39 wherein the scheduling response
information sent by the Node-B includes resource allocation for
uplink transmission.
61. The system of claim 37 wherein the wireless communication
system is a time division duplex (TDD) system.
62. The system of claim 61 wherein the WTRU goes to sleep during a
time slot that is not assigned to the WTRU.
63. The system of claim 39 wherein the scheduling information sent
by the Node-B to the WTRU includes downlink resource allocation,
and uplink resource allocation is implicitly derived from the
downlink resource allocation.
64. The system of claim 39 wherein the uplink control channel
includes a primary uplink control channel and a secondary uplink
control channel.
65. The system of claim 64 wherein the scheduling information is
transmitted via the primary uplink control channel and the packet
decoding information, the receive process information and the
feedback information are transmitted via the secondary uplink
control channel.
66. The system of claim 37 wherein the downlink control channel has
indication bits to identify the type of control information.
67. The system of claim 66 wherein the indication bits identify
that the downlink control channel contains only downlink control
information.
68. The system of claim 66 wherein the indication bits identify
that the downlink control channel contains only uplink control
information.
69. The system of claim 66 wherein the indication bits identify
that the downlink control channel contains broadcast
information.
70. The system of claim 66 wherein the indication bits identify
that the downlink control channel contains multimedia
broadcast/multicast services (MBMS) control information.
71. The system of claim 66 wherein the indication bits identify
that the control channel contains persistent scheduling
information.
72. The system of claim 66 wherein the indication bits identify
that the control channel contains paging information.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/725,064 filed Oct. 7, 2005, which is
incorporated by reference as if fully set forth herein.
FIELD OF INVENTION
[0002] The present invention is related to a wireless communication
system. More particularly, the present invention is related to a
method and system for providing control information for supporting
high speed downlink and uplink.
BACKGROUND
[0003] The third generation partnership project (3GPP) releases 5
and 6 provide HSDPA and HSUPA for high speed transmissions in the
downlink and uplink, respectively. For HSDPA and HSUPA operations,
a Node-B dynamically allocates radio resources to a plurality of
user equipments (UEs), and several physical channels are provided
to the UEs.
[0004] There are two downlink physical channels and one uplink
physical channel in HSDPA. The downlink physical channels include a
high speed shared control channel (HS-SCCH) and a high speed
physical downlink shared channel (HS-PDSCH). The uplink physical
channel includes a high speed dedicated physical control channel
(HS-PDCCH).
[0005] The HS-SCCH carriers downlink HSDPA control information. The
downlink HSDPA control information includes a channelization code
set, a modulation scheme, a transport block size, hybrid automatic
repeat request (H-ARQ) process information, redundancy and
constellation version, a new data indicator and a UE identity (ID).
A UE is assigned with up to four (4) HS-SCCHs in a cell via radio
resource control (RRC) signaling. The UE needs to monitor all of
the allocated HS-SCCH(s) before receiving control information for
HSDPA.
[0006] The HS-PDSCH carriers downlink HSDPA data packets. Based on
the processing of the HS-PDSCH, (e.g., cyclic redundancy check
(CRC) and H-ARQ processing), the UE sends a positive
acknowledgement (ACK) or a negative acknowledgement (NACK) signal
to the Node-B via the HS-DPCCH. The HS-DPCCH also carries a channel
quality indicator (CQI).
[0007] There are three downlink physical channels and two uplink
physical channels in HSUPA. The downlink physical channels include
an enhanced dedicated channel (E-DCH) absolute grant channel
(E-AGCH), an E-DCH relative grant channel (E-RGCH), and an E-DCH
H-ARQ indicator channel (E-HICH). The uplink physical channels
include an E-DCH dedicated physical data channel (E-DPDCH) and an
E-DCH dedicated physical control channel (E-DPCCH)
[0008] The E-AGCH carries an uplink E-DCH absolute grant, (i.e., a
maximum power ratio between the E-DPDCH and a dedicated physical
control channel (DPCCH)). The channelization code for the E-AGCH is
signaled separately to each UE. The E-RGCH carries an uplink E-DCH
relative grant. The E-HICH carries an E-DCH H-ARQ acknowledgement
indicator, (i.e., ACK or NACK). The E-DPDCH carries uplink HSUPA
data packets. The E-DPCCH carries transport format combination
index (TFCI) information, a retransmission sequence number (RSN)
and a happy bit.
[0009] The following Tables 1 and 2 summarize the control
information sent on the downlink for HSDPA and HSUPA, respectively,
and the following Tables 3 and 4 summarize the control information
sent on the uplink for HSDPA and HSUPA, respectively.
TABLE-US-00001 TABLE 1 Information (number of bits) When Frequency
Shared control channel (SCCH) Channelization code (7) Before data
transmission Per TTI Modulation (1) Before data transmission Per
TTI Transport block size (6) Before data transmission Per TTI H-ARQ
process information (3) Before data transmission Per TTI Redundancy
version (3) Before data transmission Per TTI New data indicator (1)
Before data transmission Per TTI UE ID (16) Before data
transmission Per TTI
[0010] TABLE-US-00002 TABLE 2 Information (number of bits) When
Frequency Absolute Grant Channel (E-AGCH) Absolute grant - in terms
of After rate request Depends on the power ratio (5) implementation
(100's of ms) UE ID or group of UE (16) After rate request Same as
above H-ARQ process activation flag After rate request Same as
above Relative Grant Channel (E-RGCH) From serving cells
UP/Hold/Down (1) Following UL Per TTI transmission From non-serving
cell Hold/Down (1) Following UL Per TTI (only for transmission
`down` command) UE ID (16) Following UL Per TTI (only for
transmission `down` command) H-ARQ Indicator Channel (E-HICH)
ACK/NACK (1) Following UL Per TTI transmission
[0011] TABLE-US-00003 TABLE 3 Information (number of bits) When
Frequency Dedicated Control Channel (HS-DPCCH) ACK/NACK (1)
Following DL Per TTI transmission CQI (5) Following DL Periodic
(multi TTI or 160 msec transmission as soon as HSDPA channel is
est.)
[0012] TABLE-US-00004 TABLE 4 Information (number of bits) When
Frequency E-DCH Dedicated Control Channel (E-DPCCH) RSN (2) With UL
data transmission Per TTI Happy bit (1) With UL data transmission
Per TTI E-TFCI (7) With UL data transmission Per TTI Rate Request
Information (on E-DPDCH) Logical Periodic and event trig- channel
ID (4) gered defined by RRC UE buffer Periodic and event trig-
occupancy (13) gered defined by RRC UE Power Periodic and event
trig- headroom (7) gered defined by RRC
SUMMARY
[0013] The present invention is related to a method and system for
providing control information for supporting high speed data
transmission. A Node-B assigns at least one downlink control
channel and at least one uplink control channel to a wireless
transmit/receive unit (WTRU). The downlink control channel and the
uplink control channel are provided to carry control information
for both the downlink and the uplink data transmission.
Conventional control channels for HSDPA and HSUPA are combined into
a reduced set of control channels for uplink and downlink. The
Node-B and the WTRU communicate control information via the reduced
set of downlink control and the uplink control channels. The WTRU
receives downlink data and transmits uplink data, and the Node-B
receives uplink data and transmits downlink data based on the
control information transmitted via the reduced set of downlink
control and the uplink control channels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a block diagram of a system configured in
accordance with the present invention.
[0015] FIG. 2 is a flow diagram of an exemplary process for
transmission of control and data packets in accordance with one
embodiment of the present invention.
[0016] FIG. 3 is a flow diagram of an exemplary process for
transmission of control and data packets in accordance with another
embodiment the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] When referred to hereafter, the terminology "WTRU" includes
but is not limited to a user equipment (UE), a mobile station
(STA), a fixed or mobile subscriber unit, a pager, or any other
type of device capable of operating in a wireless environment. When
referred to hereafter, the terminology "Node-B" includes but is not
limited to a base station, e-Node-B, a site controller, an access
point (AP) or any other type of interfacing device in a wireless
environment.
[0018] The features of the present invention may be incorporated
into an integrated circuit (IC) or be configured in a circuit
comprising a multitude of interconnecting components.
[0019] In the current 3GPP specification, there are four downlink
control channels and two uplink control channels are defined to
support HSDPA and HSUPA operation. In accordance with the present
invention, the conventional two uplink control channels are
combined to at least one uplink control channel and the
conventional four downlink control channels are combined to at
least one downlink control channel. In addition to these control
channels used for high speed uplink and downlink, information
signaled on associated dedicated control channels, (e.g., transmit
power control (TPC) on uplink and downlink DPCCHs), may also be
combined.
[0020] FIG. 1 is a block diagram of a wireless communication system
100 configured in accordance with the present invention. The system
100 includes a Node-B 102 and a WTRU 104. Between the Node-B 102
and the WTRU 104, an uplink control channel 112, a downlink control
channel 114, a downlink data channel 116 and an uplink data channel
118 are established. The channels 112-118 are allocated to the WTRU
104 preferably by the Node-B 102 or a radio network controller
(RNC). The channels 112-118 may be defined by a combination of at
least one of frequency, time, power, antenna, and code. A certain
antenna and power may be used to transmit to one user and a
different set of antenna and power may be used to transmit to
another user. Hence, multiple channels may be available at the same
time on the same frequency and code using different antenna and
power. The Node-B 102 may configure the WTRU 104 to receive and
transmit on more than one downlink and uplink control channel and
more than one downlink and uplink data channel.
[0021] The WTRU 104 listens to the downlink control channel 114 and
gets control information about the downlink data channel, the
uplink control channel and the uplink data channel. Once the WTRU
104 is configured with the uplink control channel 112 and the
downlink data channel 116, the WTRU 104 receives data or transmits
control and data information on the assigned downlink data channel
116, the uplink control channel 112 and the uplink data channel
118.
[0022] The control information may include scheduling information,
packet decoding information, receive process information and
feedback information. The packet decoding information, receive
process information and feedback information need to be transmitted
every transmission time interval (TTI). The scheduling information
may be transmitted every TTI or on a need basis.
[0023] The packet decoding information may include modulation
scheme, a coding rate and a packet size. The information regarding
the modulation scheme, the coding rate and the packet size may be
combined into one parameter for over the air transmission.
[0024] The receive process information may include an H-ARQ process
ID, a new data indicator, a redundancy version, a packet sequence
number and status information of a transmitter. The H-ARQ process
ID is needed only for asynchronous H-ARQ and is not needed for
synchronous H-ARQ. The redundancy version may be used to indicate
new data as well. The packet sequence number denotes the sequence
number of a packet within an H-ARQ process at the transmitter. This
is a useful parameter for soft or hard combining of retransmission
and a previously failed transmission. The status information may be
used for H-ARQ assisted ARQ operation where along with H-ARQ
feedback information indicating the status of on-going transmission
may be reported.
[0025] The feedback information may include H-ARQ ACK/NACK, a CQI
of the control channel, a CQI of the data channel, a packet
sequence number, an H-ARQ process ID, status information of a
receiver, transmit diversity information (phase and amplitude
information to support transmit diversity), and power control
information.
[0026] The scheduling information is either a scheduling request or
a scheduling response. The scheduling response is sent from the
Node-B 102 to the WTRU 104, and the scheduling request is sent from
the WTRU 104 to the Node-B 102. The scheduling response may include
at least one of resource allocation for a secondary downlink
control channel (if applicable), resource allocation for the
downlink data channel 116, resource allocation for the uplink
control channel 112, resource allocation for the uplink data
channel 118 and uplink timing adjustment if necessary. The
secondary downlink control channel is a control channel dedicated
to a WTRU 104 for point-to-point services and possibly to several
WTRUs in the case of point-to-multipoint services. The WTRU 104
listens to and decodes the channel following a resource allocation
indicating the secondary control channel. The WTRU 104 needs frame
alignment timing to transmit correctly in an uplink slot. Since a
clock of the WTRU 104 drifts with time and the propagation delay
changes due to mobility, the WTRU 104 needs to adjust its clock
based on the feedback from the Node-B 102. This information is
signaled whenever the Node-B 102 detects reception outside of a
specified range.
[0027] In conventional 3GPP standards, radio resources are assigned
per TTI for HSDPA and indefinitely for HSUPA. A duration field may
be added to provide flexibility in assigning radio resources so
that each resource allocation includes physical resource allocation
information and duration indicating a period during which the
physical resource allocation is effective. Duration may be a
continuous allocation of certain TTIs to the WTRU 104, or a
periodic allocation of resources for a certain time. For example,
the duration field may be denoted by "n" TTI where "n" may have
value from 1 to infinity. The value of `1` indicates the resource
is assigned for one TTI and the value of "infinity" denotes
infinite allocation of the resource. Where resources are assigned
for an infinite period, the WTRU 104 is informed explicitly about
release of the resources.
[0028] The scheduling response may be sent separately on the
downlink control channel 114. Alternatively, the scheduling
response may be multiplexed in a signal packet with at least one of
the packet decoding information, the receive process information
and the feedback information. Alternatively, the scheduling
response may be piggybacked with a data packet and sent on the
downlink data channel 116.
[0029] Alternatively, two separate downlink control channels may be
allocated to the WTRU 104, (i.e., a primary downlink control
channel and a secondary downlink control channel), and the
scheduling response may be transmitted via the primary downlink
control channel and the other control information, (i.e., packet
decoding information, receive process information, timing
adjustment and feedback information), may be transmitted via the
secondary downlink control channel. It is preferable to share the
primary downlink control channel with multiple WTRUs and dedicate
the secondary downlink control channel to a single WTRU for
point-to-point services or a set of WTRUs for point-to-multipoint
services. The primary downlink control channel is a common control
channel that all WTRUs are listening on. The secondary control
channel is a dedicated control channel that only certain WTRU(s)
addressed on the particular primary control channel listens
for.
[0030] The scheduling request may contain all or some of the
following information such as buffer occupancy for each service
type or data flow, related quality of service (QoS) requirements,
time in the queue for the first packet for each service, and the
WTRU power headroom, (i.e., available power for the requested
uplink resource channel). The scheduling request may be transmitted
separately on the uplink control channel 112, may be piggybacked
with other control information and transmitted on the uplink
control channel 112, may be piggybacked with uplink data and
transmitted on the uplink data channel 118, may be sent via a
separate packet on the uplink data channel 118, or may be sent via
a random access channel (RACH) (not shown in FIG. 1). Preferably,
during active transmission, (i.e., the uplink control channel 112
is present), the scheduling request is sent on the uplink control
channel 112 piggybacked with the other control information. In the
absence of the uplink control channel 112, the scheduling request
is preferably sent on the RACH.
[0031] For transmitting control information on the uplink control
channel 112 and the downlink control channel 114, the control
information may be separated in two parts since not all the control
information needs to be sent at any given TTI. The control
information may contain special bits to indicate whether the
control channel contains only downlink control information or only
uplink control information and whether the control channel contains
feedback information or other control information. The special bits
may also indicate whether the control channel includes broadcast
information, multimedia broadcast/multicast services (MBMS),
persistent scheduling information for periodic services, paging
information or control information for group of WTRUs.
[0032] Uplink control information from the Node-B 102 to the WTRU
104 may contain transmission feedback information. Downlink control
information from the WTRU 104 to the Node-B 102 only contains
feedback information. Uplink control information from the WTRU 104
to the Node-B 102 contains packet decoding information, receive
process information and a scheduling request (if needed). Downlink
control information from the Node-B 102 to the WTRU 104 contains
decoding information, receive process information and a schedule
response (if needed).
[0033] In a preferred embodiment, a single packet may be used
including all control information. Alternatively, multiple packets
may be used. A single packet contains all the downlink control
information and the uplink control information needed for both
downlink and uplink. The control packet contains decoding
information, receive process information, feedback information and
scheduling information, (i.e., a scheduling request or a scheduling
response). Some indication may be included in the control packet to
indicate active information elements.
[0034] The downlink control channel 114 and the uplink control
channel 112 may be a shared channel for all WTRUs or a dedicated
channel assigned to a single WTRU or a group of WTRUs. Preferably,
the uplink control channel 112 is not a shared channel due to
possible collisions between multiple WTRUs.
[0035] The uplink control channel 112 may be assigned to a WTRU 104
only during active uplink and/or downlink data transfer, (i.e., on
an as needed basis). Alternatively, the uplink control channel 112
may be assigned to a WTRU 104 even in a dormant state. Four
alternatives with respect to downlink and uplink control channel
configuration are summarized in Table 5. Method 3 and 4 are the
preferred alternatives. TABLE-US-00005 TABLE 5 Downlink control
channel Uplink control channel Method 1 Dedicated Dedicated during
dormant and active state Method 2 Dedicated Dedicated only during
active state Method 3 Shared Dedicated during dormant and active
state Method 4 Shared Dedicated only during active state
[0036] An exemplary system operation with a single downlink control
channel and per TTI basis resource allocation is explained
hereinafter with reference to Figure 2. FIG. 2 is a flow diagram of
an exemplary process 200 for transmission of control and data
packets in accordance with one embodiment of the present invention.
The WTRUs are listening to the downlink control channel 114 (step
202). Once the WTRUs 104 get the control information addressed to
it on the downlink control channel 114 from a Node-B 102, the WTRUs
114 get scheduling information, (e.g., resource allocation for a
downlink data channel, an uplink control channel and an uplink data
channel), and packet decoding and receive process information,
(e.g., a coding rate, a modulation scheme, a packet size, an H-ARQ
process ID, a redundancy version, or the like). The control packet
may also include feedback information, (i.e., H-ARQ ACK/NACK of the
previous uplink data packet and a CQI). The WTRU 104 receives the
scheduling information and configured the downlink data channel
116, the uplink control channel 112 and the uplink data channel 118
(step 204).
[0037] The None-B 102 transmits a downlink data packet to the WTRU
104 via the downlink data channel 116 (step 206). The WTRU 104
receives the downlink data packet on the downlink data channel 116
and decodes and processes the data packet based on the packet
decoding and receive process information received in the control
packet via the downlink control channel 114 (step 208).
[0038] The WTRU 104 responds with a control packet that contains
feedback information to the downlink data packet, (i.e., ACK/NACK)
(step 210). If needed, the WTRU 104 may also send a scheduling
request for uplink transmission and packet decoding and receive
process information, (i.e., a coding rate, a modulation scheme, a
packet size, an H-ARQ process ID, a redundancy version, or the
like), and may subsequently send an uplink data packet (steps 210,
212). The Node-B 102 receives and processes the uplink data packet
from the WTRU 104 using the control information in the control
packet received via the uplink control channel (step 214).
[0039] An exemplary system operation with primary and secondary
downlink control channels and duration-based resource allocation is
explained herein after with reference to FIG. 3. FIG. 3 is a flow
diagram of an exemplary process 300 for transmission of control and
data packets in accordance with another embodiment of the present
invention. Two downlink control channels, (i.e., a primary downlink
control channel and a secondary downlink control channel). The
primary control channel, (may also be called a common control
channel), is known to and monitored by each WTRU 104. Each WTRU 104
receives control information on the primary channel addressed to it
from the Node-B 102, The Node-B 102 sends scheduling information on
the primary downlink control channel (step 302). The scheduling
information includes resource assignment for a secondary downlink
control channel, a downlink data channel, an uplink control channel
and an uplink data channel. The secondary downlink control channel
is the dedicated control channel addressed to the WTRU 104. Upon
receiving the scheduling information, the WTRU 104 configures the
secondary downlink control channel, the downlink data channel, the
uplink control channel and the uplink data channel (step 304).
[0040] The Node-B 102 sends control information, (i.e., packet
related information, such as a coding rate, a modulation scheme, a
packet size, an H-ARQ process ID, a redundancy version, or the
like), on the secondary downlink control channel (step 306). The
Node-B 102 may send feedback information, (i.e., ACK/NACK of the
previous uplink data packet and a CQI), on the secondary downlink
control channel. The Node-B 102 then sends a data packet to the
WTRU 104 via the downlink data channel (step 308). The WTRU 104
decodes and processes the data packet based on the control
information received on the secondary downlink control channel
(step 310). The WTRU 104 sends a control packet that contains
feedback information to the data packet, (i.e., ACK/NACK), via the
uplink control channel (step 312). If needed, the WTRU 104 may send
a scheduling request for uplink transmissions and packet related
information along with the feedback via the uplink control channel.
The WTRU 104 then may send an uplink data packet via the uplink
data channel (step 314). The Node-B 102 receives, decodes and
processes the uplink data packet based on the control information
received via the uplink control channel (step 316). If the primary
control channel allocates a secondary control and data transmission
channel for a specified duration the WTRU 104 either continuously,
(i.e., each TTI), or periodically, (i.e., in accordance with a
reception pattern over multiple TTIs), receive the allocated
channels for the duration of the allocation.
[0041] An H-ARQ control packet for an active H-ARQ process may be
sent on an as needed basis. If the H-ARQ information, (such as an
H-ARQ process ID, a new data indicator and a redundancy version),
is included in a subsequent packet, (e.g., in a header of a
subsequent data packet), there is no need to send the scheduling
information every TTI. A downlink control packet for scheduling
information will be sent only if there is a change in resource
allocation, a modulation scheme or a packet size.
[0042] The control information may be piggybacked on a data packet.
Control information, (such as, ACK/NACK, a CQI, a scheduling
response, or a scheduling request), may be piggybacked with data in
a data packet. This is especially useful when both uplink and
downlink H-ARQ processes are active. A downlink data packet may
piggyback ACK/NACK, a CQI and a scheduling response. An uplink data
packet may piggyback ACK/NACK, a CQI and a scheduling request.
[0043] Alternatively, two uplink control channels may be provided,
(i.e., a primary uplink control channel and a secondary uplink
control channel). The primary uplink control channel is used to
send a resource request and the secondary control channel is used
to send packet decoding and receive process information and
feedback information.
[0044] Downlink resource allocation may implicitly imply uplink
resource allocation. For example, when the WTRU 104 is assigned
with resources in the downlink for HSDPA, it may implicitly mean
that specific resources are assigned in uplink for data and/or
control transmission, (such as, ACK/NACK, small data packets, and a
scheduling request for uplink transmission). The uplink data
channel and the uplink control channel may have a fixed offset in
time or frequency from the downlink data channel or the downlink
control channel, and the WTRU 104 may configure the uplink channels
based on the fixed offset.
[0045] The Node-B 102 may make the decision regarding a transmit
power, a packet size, a modulation scheme, a coding rate, and an
H-ARQ process for uplink transmissions. In this case, the control
information for uplink data packet is sent from the Node-B 102 to
the WTRU 104 via the downlink control channel.
[0046] The WTRU 104 is required to monitor downlink control
channel. If it is a time division multiplexing (TDM) system, the
WTRU 104 may go to sleep during time slots that are not assigned to
the WTRU 104 and may wake up to listen to the control channel on
the assigned time slot(s).
[0047] Although the features and elements of the present invention
are described in the preferred embodiments in particular
combinations, each feature or element can be used alone without the
other features and elements of the preferred embodiments or in
various combinations with or without other features and elements of
the present invention.
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