U.S. patent application number 13/571370 was filed with the patent office on 2013-02-14 for method for data transmission and base station and user equipment using the same.
This patent application is currently assigned to INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. The applicant listed for this patent is Chun-Chia Chen. Invention is credited to Chun-Chia Chen.
Application Number | 20130039272 13/571370 |
Document ID | / |
Family ID | 47677510 |
Filed Date | 2013-02-14 |
United States Patent
Application |
20130039272 |
Kind Code |
A1 |
Chen; Chun-Chia |
February 14, 2013 |
METHOD FOR DATA TRANSMISSION AND BASE STATION AND USER EQUIPMENT
USING THE SAME
Abstract
A method for data transmission, a base station using the same
and a user equipment (UE) using the same are provided. According to
an exemplary embodiment, the present disclosure provides a method
of data transmission, adapted for a user equipment (UE), the method
contains the steps of receiving from a base station signaling
comprising a sub-frame which comprises a control region and a data
region; decoding from the data region a first transport block
indicated by a first downlink assignment from the control region;
and decoding the first transport block to obtain a first control
information, wherein the first control information includes a
downlink assignment, an uplink grant, or an extended control region
indicator.
Inventors: |
Chen; Chun-Chia; (Changhua
County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chen; Chun-Chia |
Changhua County |
|
TW |
|
|
Assignee: |
INDUSTRIAL TECHNOLOGY RESEARCH
INSTITUTE
Hsinchu
TW
|
Family ID: |
47677510 |
Appl. No.: |
13/571370 |
Filed: |
August 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61522050 |
Aug 10, 2011 |
|
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Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04W 72/042 20130101;
H04W 76/25 20180201 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 4/00 20090101
H04W004/00 |
Claims
1. A method of data transmission, adapted for a user equipment
(UE), the method comprising: receiving from a base station
signaling comprising a sub-frame which comprises a control region
and a data region; decoding from the data region a first transport
block indicated by a first downlink assignment from the control
region; and decoding the first transport block to obtain a first
control information.
2. The method of claim 1, wherein the first control information
comprises a downlink assignment, an uplink grant, or an extended
control region indicator.
3. The method of claim 1, wherein claim 1 further comprises: if the
first control information indicates a downlink assignment,
obtaining a second transport block according to the first control
information; and processing the second transport block.
4. The method of claim 3, wherein the second transport block may be
shared by multiple UEs.
5. The method of claim 3, wherein the second transport block
contains multiple data for multiple UEs with each data designated
for a different UE.
6. The method of claim 3 wherein the step of processing the second
transport block comprises: decoding the second transport block;
obtaining a second control information from the second transport
block; and processing the second control information according to
the content of the second control information.
7. The method of claim 1, wherein if the first control information
indicates an extended control region indicator, claim 1 further
comprises: obtaining an extended control region according to the
first control information; decoding the extended control region to
obtain a second control information; if the second control
information indicates a downlink assignment, obtaining a second
transport block according to the second control information and
processing the second transport block; and if the second control
information indicates an uplink grant, storing the uplink grant and
transmitting data according to the uplink grant.
8. The method of claim 1, wherein the step of decoding the first
transport block to obtain the first control information, comprises:
decoding the first transport block to obtain packet data units
comprising a header region and a payload region, wherein the header
region comprises a type indicator, and the payload region comprises
a control information.
9. The method of claim 8, wherein the control information comprises
at least one selected from the group consisting of: a type
indicator to indicate an uplink grant, a downlink assignment, and
an extended control region indicator; a carrier indicator to
indicate one of multi-carriers; and a timing indicator to indicate
a sub-frame number.
10. The method of claim 8, wherein a logical channel identification
(LCID) in a logical channel identification field of the header
region is used as the type indicator which indicates a downlink
assignment, an uplink grant, or an extended control region
indicator.
11. The method of claim 8, wherein the type indicator is in two
reserve bits of sub-headers of the header region to indicate a
downlink assignment, an uplink grant, or an extended control region
indicator.
12. The method of claim 8, wherein the type indicator is shared
among a logical channel identification and two reserve bits of
sub-headers of the header region to indicate a downlink assignment,
an uplink grant, or an extended control region indicator.
13. The method of claim 1 further comprises: if the first control
information indicates a downlink assignment received at time t,
decoding a second transport block at time t+k according to the
first control information, wherein k is predetermined or is a value
of a timing indicator in the first control information, and
processing the second transport block at time t+k.
14. The method of claim 13 further comprises: receiving a second
downlink assignment at time t+k from decoding the control region;
decoding a third transport block according to the second downlink
assignment; and processing the third transport block.
15. The method of claim 1, further comprises: if the first control
information indicates an uplink grant received at time t,
transmitting an uplink data at time t+n according to the first
control information, wherein n is predetermined or is a value of a
timing indicator in the first control information.
16. The method of claim 15, further comprising: receiving a second
downlink assignment at time t+n from decoding the control region;
decoding a second transport block according to the second downlink
assignment; and processing the second transport block and
transmitting the uplink data according to the first control
information.
17. A user equipment (UE), comprising: a transceiver, configured to
transmit and receive wireless signals; and a processor, coupled to
the transceiver, configured to: receive from a base station
signaling comprising a sub-frame which comprises a control region
and a data region; decode from the data region a first transport
block indicated by a first downlink assignment from the control
region; and decode the first transport block to obtain a first
control information.
18. The UE of claim 17, wherein the first control information
comprises a downlink assignment, an uplink grant, or an extended
control region indicator.
19. The UE of claim 17, wherein if the first control information
indicates a downlink assignment, the processor is further
configured to: obtain a second transport block according to the
first control information; and process the second transport block
which may comprise another control information.
20. The UE of claim 19, wherein the second transport block may be
shared by multiple UEs.
21. The UE of claim 19, wherein the second transport block contains
multiple data for multiple UEs with each data designated for a
different UE.
22. The UE of claim 17 wherein if the first control information
indicates an extended control region indicator, the processor is
further configured to: obtain an extended control region according
to the first control information; decode the extended control
region to obtain a second control information; if the second
control information indicates a downlink assignment, obtain a
second transport block according to the second control information
and processing the second transport block; and if the second
control information indicates an uplink grant, store the uplink
grant and transmit data according to the uplink grant.
23. The UE of claim 17, wherein the processor is configured to
decode the first transport block to obtain the first control
information comprises: decoding the first transport block to obtain
packet data units comprising a header region and a payload region,
wherein the header region comprises a type indicator, and the
payload region comprises a control information.
24. The UE of claim 23, wherein the control information comprises
at least one selected from the group consisting of: a type
indicator to indicate an uplink grant, a downlink assignment, and
an extended control region indicator; a carrier indicator to
indicate one of multi-carriers; and a timing indicator to indicate
a sub-frame number.
25. The UE of claim 23, wherein the type indicator is in a logical
channel identification (LCID) field of the header region which
indicates a downlink assignment, an uplink grant, or an extended
control region indicator.
26. The UE of claim 23 wherein the type indicator is in two reserve
bits of sub-headers of the header region to indicator a downlink
assignment, an uplink grant, or an extended control region
indicator.
27. The UE of claim 23, wherein the type indicator is shared among
a logical channel identification and two reserve bits of
sub-headers of the header region to indicate a downlink assignment,
an uplink grant, or an extended control region indicator.
28. The UE of claim 17, wherein the processor is further configured
to: receive a second transport block at time t+k according to the
first control information if the first control information
indicates a downlink assignment received at time t, wherein k is
predetermined or is a value of a timing indicator in the first
control information, and process the second transport block.
29. The UE of claim 28 further wherein the processor further
configured to: receive a second downlink assignment at time t+k
from decoding the control region; decode a third transport block
according to the second downlink assignment; and process the third
transport block.
30. The UE of claim 17, wherein the processor is further configured
to: transmit an uplink data at time t+n according to the first
control information if the first control information indicates an
uplink grant received at time t, wherein n is predetermined or is a
value of a timing indicator in the first control information.
31. The UE of claim 30, wherein the processor further configured
to: receive a second downlink assignment at time t+n from decoding
the control region; decode a second transport block according to
the second downlink assignment; and process the second transport
block and transmit the uplink data according to the first control
information.
32. A base station comprising: a transceiver, configured to
transmit and receive wireless signals; and a processor, coupled to
the transceiver, configured to: configure data comprising a
sub-frame which comprises a control region and a data region;
encoding in the control region a first downlink assignment;
encoding in the data region a first transport block indicated by
the first downlink assignment; and encoding the first transport
block to comprise a first control information.
33. The base station of claim 32, wherein the first control
information comprises a downlink assignment, an uplink grant, or an
extended control region indicator.
34. The base station of claim 32, wherein if the first control
information comprises a downlink assignment, according to the first
control information, the processor is further configured to encode
in the data region the second transport block which may comprise
another control information.
35. The base station of claim 34, wherein the second transport
block may be shared by multiple UEs.
36. The base station of claim 34, wherein the second transport
block contains multiple data for multiple UEs with each data
designated for a different UE.
37. The base station of claim 32, wherein if the first control
information comprises an extended control region indicator, the
processor is further configured to: encode a second control
information in the extended control region which is indicated by
the first control information; and if the second control
information indicates a downlink assignment, encode in the data
region a second transport block according to the second control
information.
38. The base station of claim 32, wherein the processor is
configured to encode the first transport block to comprise the
first control information comprises: encoding in the first
transport block packet data units comprising a header region and a
payload region, wherein the header region comprises a type
indicator, and the payload region comprises a control
information.
39. The base station of claim 38, wherein the control information
comprises at least one selected from the group consisting of: a
type indicator to indicate an uplink assignment, a downlink
assignment, and an extended control region indicator; a carrier
indicator to indicate one of multi-carriers; and a timing indicator
to indicate a sub-frame number.
40. The base station of claim 38, wherein the type indicator is in
a logical channel identification (LCID) field of the header region
which indicates a downlink assignment, an uplink grant, or an
extended control region indicator to indicate the type of the
control information.
41. The base station of claim 38, wherein the type indicator is in
two reserve bits of sub-headers of the header region to indicator a
downlink assignment, an uplink grant, or an extended control region
indicator to indicate the type of the control information.
42. The base station of claim 38, wherein the type indicator is
shared among a logical channel identification and two reserve bits
of sub-headers of the header region to indicate a downlink
assignment, an uplink grant, or an extended control region
indicator.
43. The base station of claim 32, wherein the processor is further
configured to: transmit a second transport block encoded in the
data region at time t+k according to the first control information
when the first control information indicates a downlink assignment
transmitted at time t, wherein k is predetermined or is a value of
a timing indicator in the first control information.
44. The base station of claim 43, wherein the processor is further
configured to: transmit a second downlink assignment encoded in the
control region at time t+k; encode in the data region a third
transport block according to the second downlink assignment; and
transmit the third transport block.
45. The base station of claim 32, wherein the processor further
configured to: receive an uplink data at time t+n according to the
first control information if the first control information
indicates an uplink grant transmitted at time t, wherein n is
predetermined or is a value of a timing indicator in the first
control information.
46. The base station of claim 45, wherein the processor further
configured to: transmit a second downlink assignment encoded in the
control region at time t+n; encode in the data region a second
transport block based on the second downlink assignment; and
transmit the second transport block and receive the uplink data
according to the first control information.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefits of U.S.
provisional application Ser. No. 61/522,050, filed on Aug. 10,
2011. The entirety of the above-mentioned patent applications is
hereby incorporated by reference herein and made a part of this
specification.
TECHNICAL FIELD
[0002] The present disclosure generally relates to a method for
data transmission, a base station using the same and a user
equipment (UE) using the same.
BACKGROUND
[0003] In current wireless broadband standards such as Third
Generation Partnership Project Long Term Evolution (3GPP LTE), the
control channel capacity usually is highly limited. Specifically,
there may be about 10 Physical Downlink Control Channel (PDCCH)
signaling which can be sent in one Transmission Time Interval (TTI)
in a 10 MHz system bandwidth scenario, in which about at most 10
User Equipments (UEs) can be scheduled for either Downlink (DL) or
Uplink (UL) data transmission. While dedicated UEs need to follow
scheduling information carried by PDCCH, in fact a large proportion
of Control Channel Elements (CCEs) has to be used for
non-dedicated/common functions. For instance, about a total of 41
CCEs is available when 3 OFDM symbols are allocated for PDCCH, but
out of the 41 available CCEs, up to 16 Control Channel Elements
(CCEs) are commonly allocated for Common Search Space (CSS)
including control functionalities such as System Information (SI),
Paging, Random Access (RA), Transmission Power Control (TPC), and
so like. This leaves only about 25 CCEs available for dedicated UE
scheduling. For another example, in a scenario where 2 OFDM symbols
are allocated for PDCCH, only about 10 CCEs out of a total of 25
CCEs are available for dedicated UE scheduling.
[0004] However, the channel capacity is further limited under the
circumstance of Carrier Aggregation (CA). In Carrier Aggregation
(CA), cross-carrier scheduling may be used to schedule resources on
another serving cell and therefore reduce inter-cell interference
in Heterogeneous Networks. In addition, cross carrier scheduling
may be used to schedule resources on non-backward compatible
carriers. For instance, when a wireless communication system is
operating with non-backward compatible carriers, during a sub-frame
in which the allocated frequency band for a first carrier (CC1) may
contain data in the Physical Downlink Shared Channel (PDSCH) and a
second carrier (CC2) may contain data in its PDSCH, the control
region of a first carrier (CC1) may actually contain PDCCH for both
CC1 and CC2 while no PDCCH or Physical Hybrid ARQ Indicator Channel
(PHICH) or Physical Control Format Indicator Channel (PCFICH) would
exist in the control region of CC2 in order to avoid interference
to control region of other cells. For another example of
non-backward compatible carriers, the non-backward compatible
carrier is close to the backward compatible carrier and may only
contain data region. The control region of the backward compatible
carrier may contain control signaling for both data regions of
backward and non-backward compatible carrier. This means that using
carrier aggregation would further require more control channel
capacity.
[0005] In a practical scenario, for example, the applications of
instant communications (e.g. messages services and social networks)
may have the characteristics of variant packet inter-arrival time,
and small size of packet. In additional, the time of arrivals
between packets may be large. If a scheme of periodic resource
allocation is adopted, it would result in a waste of resource
allocation if the scheduled period were short but would otherwise
adversely affect interactivity if the period were long. For real
time services such as gaming, video surveillance, remote control,
and so like, tight delay and frequent transmissions of data having
variable sizes are required. Also for machine type communication in
general, such as machine-to-machine traffic, a large amount of
small data traffic with variable sizes is required. Therefore, all
that has been described necessitate a mechanism to reduce the
control signal (e.g. PDCCH) overhead.
[0006] Semi-Persistent Scheduling (SPS) could be used to reduce the
control signal overhead. For services involving a semi-static
packet rate such as VoIP, SPS can be configured to reduce the
control signal overhead. For this kind of service to be
implemented, the timing and the amount of radio resources require
predictability. The SPS enables radio resources to be
semi-statically configured and allocated to a UE for a longer time
period other than one sub-frame, and the SPS may avoid the need for
transmitting specific downlink assignment messages or uplink grant
messages over the PDCCH for each sub-frame. However, the SPS may
not be suitable for other Internet applications such as social
network applications since updating information on the social
network website could not be easily predicted.
SUMMARY
[0007] Accordingly, the present disclosure is directed to a method
for data transmission, a base station using the same and a user
equipment (UE) using the same. According to an exemplary
embodiment, the present disclosure provides a method of data
transmission, adapted for a user equipment (UE), the method
contains the steps of receiving from a base station signaling
comprising a sub-frame which comprises a control region and a data
region; decoding from the data region a first transport block
indicated by a first downlink assignment from the control region;
and decoding the first transport block to obtain a first control
information.
[0008] According to an exemplary embodiment, the present disclosure
provides a user equipment which has a transceiver and a processor.
The transceiver transmits and receives wireless signals. The
processor is coupled to the transceiver and is configured to
receive from a base station signaling comprising a sub-frame which
comprises a control region and a data region, decode from the data
region a first transport block indicated by a first downlink
assignment from the control region, and decode the first transport
block to obtain a first control information.
[0009] According to an exemplary embodiment, the present disclosure
provides a base station which contains a transceiver and a
processor. The transceiver transmits and receives wireless signals.
The processor is coupled to the transceiver and is configured to
configure data comprising a sub-frame which comprises a control
region and a data region, encode in the control region a first
downlink assignment, encode in the data region a first transport
block indicated by the first downlink assignment, and encode the
first transport block to comprise a first control information.
[0010] The accompanying drawings are included to provide a further
understanding of the disclosure and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the disclosure and, together with the description,
serve to explain the principles of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a wireless communication system including
an eNB communicating with at least one UEs in accordance with an
exemplary embodiment.
[0012] FIG. 2 illustrates the contents of sub-frames of data used
in the wireless communication system in accordance with an
exemplary embodiment of the present disclosure.
[0013] FIG. 3A illustrates an example of the control information
and data in a sub-frame.
[0014] FIG. 3B illustrates piggyback control information in a
transport block according to an exemplary embodiment.
[0015] FIG. 3C illustrates using an extended control region.
[0016] FIG. 3D illustrates using piggyback control information to
indicate the location of the extended control region according to
an exemplary embodiment.
[0017] FIG. 4 is a process flow chart illustrating a method of
using piggyback control information for data transmission according
an exemplary embodiment.
[0018] FIG. 5 illustrates various approaches of allocating
piggyback control information elements in a MAC PDU according to an
exemplary embodiment.
[0019] FIG. 6 is a process flow chart illustrating a process of
piggyback control information in a transport block for a downlink
assignment according to an exemplary embodiment.
[0020] FIG. 7 is a flow chart illustrating parallel a PDCCH
assignment and a piggyback downlink assignment according to an
exemplary embodiment.
[0021] FIG. 8 is a process flow chart illustrating a process of
piggyback control information in the transport block for an uplink
grant according to an exemplary embodiment.
[0022] FIG. 9 is a flow chart illustrating parallel a PDCCH
assignment and a piggyback uplink grant according to an exemplary
embodiment.
[0023] FIG. 10 illustrates a process of piggybacking control
information for a combination of DL assignment and UL grant
according to an exemplary embodiment.
DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS
[0024] In this disclosure, 3GPP-like keywords or phrases are used
merely as examples to present inventive concepts in accordance with
the present disclosure; however, the same concept presented in the
disclosure can be applied to any other systems such as IEEE 802.11,
IEEE 802.16, WiMAX, sensor network and so like by persons of
ordinarily skilled in the art.
[0025] Throughout the disclosure, the term PDCCH is used to
represent the a control region or a downlink control channel to
indicate downlink (DL)/uplink (UL) resource allocation assignment,
the same concept by the present disclosure can also be applied to
other downlink control channels including DL-MAP, UL-MAP, MBS-MAP,
and so like through simple analogy.
[0026] The term "eNodeB" or "eNB" in this disclosure may be, for
example, a base station (BS), a Node-B, an advanced base station
(ABS), a base transceiver system (BTS), an access point, a home
base station, a relay station, a scatterer, a repeater, an
intermediate node, an intermediary, and/or satellite-based
communication base stations, remote radio header (RRH), and so
like.
[0027] The term "user equipment" (UE) in this disclosure may be,
for example, a mobile station, an advanced mobile station (AMS), a
server, a client, a desktop computer, a laptop computer, a network
computer, a workstation, a personal digital assistant (PDA), a
tablet personal computer (PC), a scanner, a telephone device, a
pager, a camera, a television, a hand-held video game device, a
musical device, a wireless sensor, a smart phone, and so like. In
some applications, a UE may be a fixed computer device operating in
a mobile environment, such as a bus, train, an airplane, a boat, a
car, and so like.
[0028] Presently, with applications using small data packets with
diverse data inter-arrival time on the rise, the control region in
a sub-frame carrying control information may require more space in
order to accommodate the increase of the control signaling.
However, since the PDCCH capacity in the control region is highly
limited, there is a need to either reduce the PDCCH overhead or to
increase the control region space. In this present disclosure, a
method for data transmission and a base station and a user
equipment using the same method are proposed to enhance the data
transmission by piggybacking control information in the transport
block (TB). Here, the transport block may refer to data in the data
region of wireless signals transmitted from a base station to a
UE.
[0029] FIG. 1 illustrates a wireless communication system according
to an exemplary embodiment. The wireless communication system
includes an eNB (101) in communication with at least one UEs (103,
105, . . . 10x) in accordance with a wireless communication
standard. Each UE contains, for example, at least a transceiver
circuit (111), an analog to digital (A/D)/digital to analog (D/A)
converter (113), and a processing circuitry (115). The transceiver
circuitry (111) is capable of transmitting uplink signal and/or
receives downlink signal wirelessly. The transceiver circuitry
(111) may also perform operations such as low noise amplifying,
impedance matching, frequency mixing, up or down frequency
conversion, filtering, amplifying, and so like. The transceiver
circuitry (111) also includes an antenna unit (not shown in FIG.
1). The analog-to-digital (A/D)/digital-to-analog (D/C) converter
(113) is configured to convert from analog signal format to digital
signal format during downlink signal processing and digital signal
to analog signal during uplink signal processing. The processing
circuitry (115) is configured to process digital signal and to
perform procedures of the proposed method for data transmission in
accordance with exemplary embodiments of the present disclosure.
Also, the processing circuitry (115) may include a memory unit (not
shown in FIG. 1) to store data or record configurations assigned by
the eNB 101. The eNB (101) contains similar elements which lead to
the converted digital signal to be processed by its processing
circuitry (117) so as to implement the method for data transmission
in accordance with exemplary embodiments of the present
disclosure.
[0030] FIG. 2 illustrates the contents of a sub-frame used in the
wireless communication system in accordance with an exemplary
embodiment of the present disclosure. According to FIG. 2, there
could be, for example, 10 sub-frames per frame (200), and each
sub-frame is a transmission time interval (TTI). Within each
sub-frame, in sub-frame #0 (201) for example, there may be a
control region (210) and a data region (220). Conventionally, the
control region (210) may include PDCCH which contains resource
allocation information such as DL assignment and UL grant.
Specifically, the Downlink Control Information (DCI) in PDCCH
provides resource allocation information for downlink or uplink.
The data region (220) may include PDSCH which is configured to
carry numerous transport blocks (TB) (230). It is possible that the
control signal overhead can be overwhelming when there are a lot of
demands for dynamic downlink or uplink resource assignment.
Therefore, one of the concepts behind piggyback control information
is to carry DCI information in the transport blocks (TB). Also,
another one of the concepts behind piggyback control information is
to carry the location information of an extended control region in
the TB. A base station or eNB may transmit DL data to a UE through
a PDCCH and PDSCH or assign UL resource on a PUSCH to a UE through
a PDCCH. A UE may monitor a DL channel, e.g., PDCCH and PDSCH, in a
sub-frame to obtain the control information and data. FIG. 3A
illustrates an example of the control information and data in a
sub-frame transmitted from an eNB. Upon a UE receiving from a base
station DL signaling containing PDCCH (32) and PDSCH (34), the DCI
information (30) could be obtained by the UE through blindly
decoding the PDCCH. The PDCCH (32) may be referred to as the
control region and PDSCH (34) may be referred to as payload region,
and a MAC PDU in a sub-frame may also be known as a packet data
unit or a packet data or a radio resource. The DCI information
obtained by the UE may indicate the location of a TB (36) which
contains data for the UE. In another example, the DCI information
may indicate an uplink resource for UE to transmit UL data.
[0031] FIG. 3B illustrates piggybacking control information in a
TB. Upon a UE receiving from a base station DL signaling containing
PDCCH (32) and PDSCH (34), the DCI information (30) could be
obtained by the UE through blindly decoding the PDCCH. The DCI
information obtained by the UE may indicate the location of a TB
(36) which contains data for the UE. The TB (36) may contain
control information for resource allocation, namely DCI
information, related to an uplink grant or a downlink assignment.
In other words, the control information which would normally be in
the PDCCH (32) is piggybacked onto the PDSCH region (34), namely a
TB (36) in the data region. The TB may contain one or more DCI (40)
information for downlink resource assignment or/and one or more DCI
(40) information for uplink resource assignment. If the DCI (40)
information contains the downlink resource assignment, the downlink
resource assignment may indicate a TB (43) in this sub-frame or
another TB in the future sub-frame. The UE may then acquire a TB
(43) based on the DCI (40) information. The TB (43) may contain
another set of piggyback control information as well.
Alternatively, if the DCI (40) information contains the UL resource
assignment, the UE may store the UL resource assignment, namely UL
grant, and then will transmit UL data based on the UL grant in a
future sub-frame.
[0032] FIG. 3C illustrates an example of using an extended control
region, namely extended physical downlink control channel
(E-PDCCH), for carrying DCIs. The PDSCH (34) may contain the
extended physical downlink control channel (E-PDCCH) (45) which is
an extended control region used to carry control signaling such as
DCIs. When the UE successfully decodes DCI(s) (46) in the E-PDCCH,
UE would discover that the DCI is for a DL resource assignment or
for an UL resource assignment. If the DCI (40) indicates a DL
resource, then the UE decodes the TB (47) based on the DCI
information (46) to obtain the DL data. Alternatively, if the DCI
(46) indicates an UL resource, then the UE stores the DCI (46)
information, namely UL grant, and will transmit the UL data based
on the UL grant in the future sub-frame.
[0033] FIG. 3D illustrates piggyback control information to
indicate the location information of the extended control region.
The UE first blindly decodes the PDCCH (32) to obtain the DCI (30),
which subsequently indicates the location of a TB (36). The UE then
decodes the TB (36) according to the parameters in the DCI (30).
Upon the successfully decoding of the TB (36), an extended control
region indicator or an E-PDCCH indicator (49) might be found in the
TB (36). The E-PDCCH indicator indicates the location of an E-PDCCH
region in the PDSCH (34) of a sub-frame. E-PDCCH may be in the
current sub-frame or in the future sub-frame based on
predetermination or the parameters in the extended control region
indicator. Next, the UE may blindly decode the E-PDCCH (45) which
may contain a set of DCIs (46). A DCI (46) for downlink resource
assignment may indicate a location of another TB (47). The TB (47)
may also contain another set of piggyback control information. The
UE then decodes the TB (47) based on the parameters in DCI (46) to
obtain the DL data and maybe another piggyback control information
which may indicate an uplink grant or a downlink assignment. The UE
would deal with the UL grant or the DL assignment as the previous
description. Alternatively, a DCI (46) for UL resource assignment
may indicate the UL resource information, namely UL grant. The UE
stores the UL grant and then will transmit UL data in the future
time. An extended control region could be shared by multiple UEs.
There may have multiple extended control regions in a data region
(PDSCH) of a time slot.
[0034] A TB indicated by a piggyback control information may be
shared by different UEs. In other words, the location of a TB may
be indicated by multiple piggyback control information from other
different TBs received by different UEs. This one TB may contain
data for one UE. The UEs may try to decode the TB. When decoding
successfully, the UE stores data and forwards the data to an upper
layer. The UE may send an ACK to the base station or eNB. When
decoding unsuccessfully, the UE may discard this piggyback control
information.
[0035] In another exemplary embodiment, this one TB indicated by
multiple piggyback control information may contain multiple data
for multiple UEs with each data designated for a different UE. The
UEs may decode this TB and subsequently find the corresponding data
in the TB for each UE based on the UE indication information in the
TB or based on a predetermined location. For example, UE IDs or a
bitmap in the TB header indicates whether or not the corresponding
data exists in this TB. Furthermore, the data size information for
each UE may be predetermined or contained in this TB header.
[0036] FIG. 4 is a process flow chart illustrating a method for
data transmission of an exemplary embodiment. In step S401, a UE
receives PDCCH and PDSCH. Next in step S403, the UE blindly decodes
PDCCH to obtain DCI information with assignment information which
is assigned by the base station to the UE. Next, in step S405, the
UE locates a TB based on the DCI information, and then after the TB
is located, the TB is decoded according to the assignment
information in the DCI. Next, in step S407, assuming that the TB is
successfully decoded, MAC (Media Access Control) PDU (Protocol Data
Unit) can be obtained by the UE from the TB. The UE would then be
able to obtain piggyback control information from the MAC PDUs of
the TB. Next, in step S409, the obtained control information may be
stored in the memory of the UE. The control information may be used
for a downlink resource assignment at the current time or in a
future time, may be used for an uplink resource assignment at the
current time or in a future time, or may be used for indicating a
location of an extended control region at the current time or in a
future time. In step S411, the downlink assignment, the uplink
assignment, or the extended control region indicator is
processed.
[0037] A TB may contain one or multiple Media Access Control
Protocol Data Units (MAC PDU) or PDU. A MAC PDU is also referred to
a packet data unit. In an embodiment of the disclosure, the
piggyback control information may be placed inside the MAC control
elements (MAC CE) of a MAC PDU. A MAC CE is also referred to a part
of the payload region of a packet data unit. The piggyback control
information may be a downlink (DL) assignment information for the
DL TB or an uplink grant information for the UL resource or an
extended control region indicator for the location of extended
control region. A TB may contain one or more piggyback control
information. That is, a TB may contain one or more piggyback
control information for DL assignment, one or more piggyback
control information for UL grant, and one or more piggyback control
information for extended control region indicators. A piggyback
control information in the TB may indicate an DL assignment or an
UL grant or an extended control region indicator in the current
time slot or in the future time slot. For example, a type indicator
could be used in a MAC CE to indicate that the piggyback control
information in a TB for a specific UE is a DL assignment or an UL
grant or an extended control region indicator.
[0038] In some embodiments, a type indicator may be placed in a MAC
sub-header or in the header region of a packet data unit. A MAC
header is also referred to the header region of a packet data unit.
A header region of a packet data unit may contain one or more
sub-headers. FIG. 5 illustrates indicators in MAC sub-header or in
MAC CE according to an exemplary embodiment. According to FIG. 5, a
MAC PDU (500) contains a MAC header (510), a few blocks of MAC CE
(532) followed by payloads of data packets including MAC Service
Data Units (SDU) (534), and optional padding (536).
[0039] A MAC header (510) may contain numerous MAC sub-headers
(520). A MAC sub-header may indicate a corresponding MAC CE or a
MAC SDU. According to an exemplary embodiment, there may be three
different formats for a MAC sub-header. For the first format (522)
of a MAC sub-header, there are 8 bits of information. R is a
reserved bit. E is an extension field which is a flag indicating
whether more MAC sub-header fields are present in a MAC header or
not. The Logic Channel identification (LCID) (5221) field
identifies the logic channel instance of the corresponding MAC SDU
or the type of the corresponding MAC CE or padding.
[0040] For the second format (524) of MAC sub-header, there is an
additional byte of a bit F and a 7 bit length field L, where F is
the field which indicates the size of the length field (L), and L
is the length field indicating the length of the corresponding MAC
SDU or variable-sized MAC CE in bytes. If the size of the MAC SDU
or variable-sized MAC control element is less than 128 bytes, the
value of the F field is set to 0, otherwise it is set to 1.
[0041] For the third format (526) of the MAC sub-header, the value
of the F field is set to 1 and the L field is lengthened as there
are a total of 15 bits available for the L length field.
[0042] In another embodiment, an LCID field may also be used as a
type indicator to indicate a DL assignment, an UL grant, or an
extended control region indicator in a MAC CE. For example, one
LCID value in the LCID field of a MAC sub-header can be used to
indicate a DL assignment in a MAC CE, another LCID value can be
used to indicate an UL grant in a MAC CE, and another one LCID
value can be used to indicate an extended control region indicator
in a MAC CE.
[0043] In an exemplary embodiment, if an LCID value is shared
between a DL assignment and an UL grant, an indicator is further
needed for indicating that the current piggyback control
information in a MAC CE is a DL assignment or an UL grant. For
example, an R bit in MAC subheader can be further used as the
indicator. For example, R=0 may indicate a DL assignment, and R=1
may indicate an UL grant. For another example, a type indicator in
the piggyback control information in a MAC CE may be used. In
another exemplary embodiment, if an LCID value is shared among a DL
assignment, an UL grant and an extended control region indicator, a
type indicator is further needed for indicating that the current
piggyback control information in a MAC CE is a DL assignment, an UL
grant or an extended control region indicator. For example, two R
bits in MAC sub-header can be further used to indicate that the
current piggyback control information in a MAC CE is a DL
assignment, an UL grant or an extended control region indicator.
For example, RR=01 may indicate a DL assignment, RR=10 may indicate
an UL grant, and RR=11 may indicate an extended control region
indicator. For another example, one R bit in MAC subheader can be
further used to indicate that the current piggyback control
information in a MAC CE is a resource allocation (DL assignment or
UL grant) or extended control region indicator. Furthermore, a type
indicator in the piggyback control information in a MAC CE may be
used to indicate that the current piggyback control information in
a MAC CE is a DL assignment or an UL grant. Therefore, the type
indicator is shared among a logical channel identification and two
reserve bits of sub-headers of the header region to indicate a
downlink assignment, an uplink grant, or an extended control region
indicator.
[0044] For a DL assignment in a piggyback control information, the
DCI information may include the following parameters: a type
indicator for indicating a DL assignment, a carrier indicator to
indicate one of multi-carriers, resource allocation header,
resource block assignment, modulation and coding scheme (MCS), HARQ
process number, new data indicator, redundancy version, TPC command
for PUCCH, downlink assignment index, and timing indicator (k),
where k is an integer greater than or equal to 0, and in some
cases, k may be 0 to indicate the TB is for the current time slot.
Timing indicator (k) indicates a sub-frame number. In other words,
a downlink assignment under the method for data transmission with
the piggyback control information may indicate that a TB is for the
current time slot or for a future time slot. If the timing
indicator (k) field is absent, the DL assignment is for the current
time slot or for a future time slot with a predetermined time
period. If a type indicator is in MAC sub-header, the type
indicator in the DCI information may be not needed. The
aforementioned parameters such as the type indicator, the carrier
indicator, and the timing indicator (k) are novel indicators
proposed in accordance with an exemplary embodiment.
[0045] For an UL grant in a piggyback control information, the DCI
information may include the following parameters: a type indicator
for indicating an UL grant, a carrier indicator, a flag for
format0/format1A differentiation, a frequency hopping flag, a
resource block assignment and a hopping resource allocation, a
modulation and coding scheme and redundancy version, a new data
indicator, a TPC command for scheduled physical uplink shared
channel (PUSCH), cyclic shift for demodulation reference signal (DM
RS) and optical carrier component (OCC) index, UL index, Downlink
Assignment Index (DAD, channel state information (CSI) request,
sounding reference signal (SRS) request, resource allocation type
and timing indicator (n), where n is an integer greater than or
equal to 0. The timing indicator indicates that piggyback control
information for UL resource assignment is for the current time slot
or for a future time slot. If a type indicator is in MAC
sub-header, the type indicator in the DCI information may be not
needed. If the timing indicator (n) field is absent, the UL grant
is for a future time slot with a predetermined time period. The
aforementioned parameters listed for UL grant such as the type
indicator, the carrier indicator and the timing indicator (n) are
novel indicators proposed according to an exemplary embodiment.
[0046] A base station or an eNB may start or stop using piggy back
control information for any UE based on statistics of UE data
traffic and/or the usage of PDCCH control region. A base station is
likely to start piggy back control information as the UE data
traffic experiences an increase or as the usage of PDCCH control
region is high.
[0047] For re-transmission, a UE may send ACK if the UE correctly
decodes the data, and a UE may not send NACK if the UE does not
correctly decode the data. If a base station does not receive an
ACK from the UE, the base station may re-transmit the same resource
allocation assignment according to conventional rules. In the case
of piggyback control information for which an extended control
region, or E-PDCCH is used, the downlink transmission only carrying
extended control region information may not need HARQ, and the UE
may not need to provide ACK or NACK feedback.
[0048] The eNB or base station may transmit the DL data which is
indicated by the piggyback control information to one of the UEs,
and the eNB may transmit other DL data for the same UE by normal
PDCCH assignment at the same time slot. In other words, the base
station can configure a UE for piggyback control information in
conjunction with normal PDCCH assignment. Also, the piggyback
control information operation and the normal control information
operation for each UE could either be performed in parallel or
exclusive at any time slot.
[0049] FIG. 6 is a process flow chart illustrating the process of
piggybacking control information operation in the TB for a downlink
resource assignment according to an embodiment. An exemplary
embodiment of the procedure of DL assignment is as follows: The DL
assignment can be either from PDCCH or from the piggyback control
information in a TB previously received. In step S601, an UE
receives PDCCH and PDSCH at time t. In step S603, if an UE finds a
DL assignment in the PDCCH, the UE executes step S605, otherwise
the process ends. In the step S605, the UE decodes TB in PDSCH
based on the DL assignment information which is received in this
PDCCH, or is from a piggyback control information for a DL
assignment received in this time slot or is from a stored DL
assignment received in the previous time slot. The UE then
processes this TB to obtain packet data and the piggyback control
information if any from this TB. If the packet data is found in
this TB, the UE may forward the data to an upper layer. In step
S617 the UE determines if a stored DL assignment obtained from the
previously received TB indicates DL resource for this current time
slot. If the determination results in a yes in the step S617, then
in step S619, the UE receives PDSCH and may also receive PDCCH for
normal DL/UL assignment. Then, in step S605 the UE decodes the TB
based on the stored DL assignment information.
[0050] In step S607, the UE would attempt to find piggyback control
information for DL assignment in this TB. If no piggyback control
information for DL assignment in the TB is found in the step S607,
then the process for handling DL assignment ends. If a DL
assignment in the TB is found by the UE in the step S607, then in
step S609 the UE determines if the DL assignment is for the current
time slot (e.g., the timing indicator field, k=0 or the field is
absent). If the DL assignment is for the current time slot, then
the UE processes the TB based on this DL assignment as the
procedure loops back to step S605.
[0051] If however back in the step S609, the resource allocation is
not for the current time slot but for a future time slot (e.g.,
t+k, where k is a number greater than or equal to zero and is a
multiple of a sub-frame period), then in step S611 the UE stores
the DL assignment as the UE would need to receive PDSCH at time
t+k. Note that the parameter k may be predetermined or defined in
the DL assignment information, i.e., the timing indicator. The UE
would then process the TB in PDSCH at time t+k based on the stored
DL assignment information. The processing of the TB would include
for UE receiving downlink data, or for base station transmitting
downlink data.
[0052] FIG. 7 is a flow chart illustrating parallel PDCCH
assignment and piggyback assignment according to an exemplary
embodiment. An eNB may transmit more than one TB at the same time
slot to a UE by PDCCH assignment and piggyback assignment. The UE
on the other hand may receive more than one TB at the same time
slot based upon PDCCH assignment and piggyback assignment. An
exemplary embodiment of the parallel PDCCH assignment and piggyback
assignment procedure is as follows.
[0053] In step S701, a UE receives PDCCH and PDSCH. In step S703,
if the UE finds a DL assignment in the PDCCH, then in step S705,
the UE would decode a TB in PDSCH based on the DL assignment
information from the PDCCH and then processes this TB and executes
step S707. If in step S703, the UE does not find a DL assignment in
PDCCH, then no TB is indicated as step S707 would be executed
instead. In step S707, the UE determines if a stored DL assignment
obtained from a previous piggyback TB block indicates a DL resource
in this current time slot. If the DL resource is for this time
slot, then in step S709 the UE decodes a TB in PDSCH based on the
DL assignment information and then processes this TB. If there is
not a stored DL assignment in step S707, then the UE executes step
S711.
[0054] Next, in step S711, if one or more DL assignments in these
decoded TBs is found, then in step S713, the UE checks if the DL
assignment(s) is for this time slot (e.g., the timing indicator
field, k=0 or the field is absent). If the DL assignment is for the
current time slot, then the UE processes the TB based on this DL
assignment as the procedure loops back to step S709, since the TB
decoded back in step S709 could contain yet another DL resource
assignment. If however in the step S713, the resource allocation is
not for the current time slot but for a future time slot (e.g.,
t+k, where k is a number greater than or equal to zero and is a
multiple of a sub-frame period), then in step S715 the UE stores
the DL assignment as the UE would need to receive PDSCH at time
t+k. Note that the parameter k may be predetermined or defined in
the DL assignment information, i.e., the timing indicator. The UE
would then process the TB in PDSCH at time t+k based on the stored
DL assignment information.
[0055] FIG. 8 is a flow chart illustrating the process of
piggybacking control information operation in the TB for an UL
resource assignment according to an embodiment. Referring to FIG.
8, the procedure of an UL grant is described as follows: In step
S801, an UE receives PDCCH and PDSCH at time t. Next, in step S803,
the UE determines whether a DL assignment in PDCCH is found. If
not, the process ends. Otherwise, the UE continues to determine if
a DL assignment in PDCCH is found. If the determination result is
yes in the step S803, the UE continues to execute step S805. In the
step S805 the UE decodes TB in PDSCH based on the DL assignment
information from the PDCCH and then process this TB. In step S807,
if the UE finds an UL grant in this TB, then in step S809 UE stores
the UL grant for future uplink. In step S811 which occurs at time
t+n, in which n stands for the total time for n numbers of
sub-frames to elapse, UE prepares to transmit a TB in PUSCH at time
t+n according to the information in the stored UL grant. It is
noted that the number n could be non-zero since the UE could always
wait for a number of sub-frames to elapse before transmitting the
TB. In addition, the number n may be pre-determined or obtained
from the timing indicator in the UL grant. In the step S813, the UE
transmits a TB in PUSCH based on the stored UL grant information at
time t+n.
[0056] FIG. 9 is a flow chart illustrating parallel PDCCH
assignment and piggyback control information for uplink resource
assignment according to an exemplary embodiment. The steps S901 to
S909 and step S913 correspond to steps S801 to S809 and step S813
respectively, and therefore the explanation for these steps is not
repeated. Comparing with step S811, in step S911 the UE may need to
process more than one UL grant, i.e., the UE may have UL grant,
which indicates the UL resource for this time slot, from PDCCH or
from a piggyback control information. The other difference between
FIG. 8 and FIG. 9 is situated in two additional steps, namely S915
and S917. In S915, the UE blindly decode DCI in the PDCCH for an UL
grant. If an UL grant is found in PDCCH, then the UE processes this
UL grant in parallel with the piggyback uplink assignment found in
the steps S901 to S909. In step S917, an UL grant found in PDCCH is
then stored and is to be transmitted in PUSCH in the step S913. In
step S913, the UE may transmit more than one UL data (or TB) on
PUSCH according to the stored UL grants which may from the PDCCH or
from the piggyback control information.
[0057] Furthermore, the process of DL resource assignment from
PDCCH or piggyback control information and the process of UL
resource assignment from PDCCH or piggyback control information
could both be processed in parallel. FIG. 10 is a flow chart
illustrating an exemplary embodiment for the combination of DL
assignment and UL grant from PDCCH or from piggyback control
information. Since this procedure is similar to the procedure
described by FIG. 6, FIG. 8, and their corresponding written
descriptions, this process flow is quickly described. The steps of
S1001, S1003, S1005, S1007, S1009, and S1011 would be respectively
identical to S601, S603, S605, S607, S609, and S611 as illustrated
in FIG. 6. However, in step S1013 of FIG. 10, an UL grant in the
decoded TB could be found instead of a DL resource allocation. In
this case, the handing for the UL grant by the UE in steps S1013,
S1015, S1021, and S1023 would be respectively identical S807, S809,
S811, and S813 of FIG. 8. Therefore, the description is not
repeated.
[0058] The procedures of executing downlink assignment, uplink
assignment, parallel processing of PDCCH assignment and piggyback
assignment, and processing DL assignment and UL grant in
combination for the exemplary embodiments as described in FIGS. 3B,
3C, and 3D are similar and are not repeated again. In addition, the
DL/UL assignment also could be obtained from the extended control
region (E-PDCCH). So the procedure of the DL/UL assignment from
PDCCH or piggyback control information could also be combined with
a pre-determined extended control region or an extended control
region indicated by the piggyback control information. The combined
procedures are similar to the procedures of the exemplary
embodiments and are not repeated again.
[0059] Even though the examples of processing downlink and uplink
assignment through piggyback control information are disclosed from
a UE's point of view, the implementation of these processes for a
base station would be apparent for a person of ordinarily skilled
in the art.
[0060] In view of the aforementioned descriptions, the present
disclosure is able to improve data transmission by piggybacking
control information in the TB. Piggyback control information in the
data region of a sub-frame could provide pre-allocated resource for
both DL or UL resource and thus reduce the packet delay. In
addition, piggyback control information can provide dynamic
interval SPS (Semi-Persistent Scheduling)-like resource and robust
control information in PDSCH rather than in PDCCH. Since the same
data may be in two resource blocks, the transmit diversity gain can
be increased when one data may be assigned by normal PDCCH and the
other may be assigned by piggyback control information.
Furthermore, the embodiments of the present disclosure allow an UE
to process multiple DL TBs and multiple UL resource blocks in a
time slot. Extend Control region could be also taken advantage as
it is used for allocating DL resource or UL resource by the
piggyback control information.
[0061] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
disclosed embodiments without departing from the scope or spirit of
the disclosure. In view of the foregoing, it is intended that the
disclosure cover modifications and variations of this disclosure
provided they fall within the scope of the following claims and
their equivalents.
* * * * *