U.S. patent application number 16/807799 was filed with the patent office on 2020-07-02 for physical downlink control channel for fifth-generation networks.
The applicant listed for this patent is Intel IP Corporation. Invention is credited to Ralf Matthias Bendlin, Jong-Kae Fwu, Huaning Niu, Gang Xiong, Yushu Zhang, Yuan Zhu.
Application Number | 20200213982 16/807799 |
Document ID | / |
Family ID | 57319640 |
Filed Date | 2020-07-02 |
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United States Patent
Application |
20200213982 |
Kind Code |
A1 |
Xiong; Gang ; et
al. |
July 2, 2020 |
PHYSICAL DOWNLINK CONTROL CHANNEL FOR FIFTH-GENERATION NETWORKS
Abstract
Disclosed herein are apparatuses, systems, and methods using or
implementing a control channel (PDCCH) design. The PDCCH can occupy
an initial number of OFDM symbols of a downlink subframe, while
occupying less than the full system bandwidth. The PDCCH can be
time division multiplexed (TDM) with a shared channel (PDSCH) or
frequency division multiplexed (FDM) with a PDSCH. The PDCCH can
further be multiplexed with another PDCCH in a contiguous or
non-contiguous region. Resources allocated to the PDCCH can overlap
or partially overlap resources allocated to the PDSCH. An Evolved
Node-B (eNB) can provide configuration information for the PDCCH
design in Radio Resource Control (RRC) signaling to a user
equipment (UE), or through use of a Master Information Block (MIB)
or System Information Block (SIB).
Inventors: |
Xiong; Gang; (Beaverton,
OR) ; Fwu; Jong-Kae; (Sunnyvale, CA) ; Zhu;
Yuan; (Beijing, CN) ; Bendlin; Ralf Matthias;
(Cedar Park, TX) ; Zhang; Yushu; (Beijing, CN)
; Niu; Huaning; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Intel IP Corporation |
Santa Clara |
CA |
US |
|
|
Family ID: |
57319640 |
Appl. No.: |
16/807799 |
Filed: |
March 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15568746 |
Oct 23, 2017 |
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PCT/US2015/065093 |
Dec 10, 2015 |
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16807799 |
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62165115 |
May 21, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/0446 20130101;
H04W 88/02 20130101; H04W 72/042 20130101; H04L 5/0082 20130101;
H04L 5/0037 20130101; H04L 27/2602 20130101; H04L 5/0094 20130101;
H04L 5/0053 20130101; H04B 7/00 20130101; H04B 7/0617 20130101;
H04L 5/0023 20130101; H04L 5/0051 20130101; H04J 3/16 20130101;
H04J 11/00 20130101; H04L 5/0044 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04B 7/00 20060101
H04B007/00; H04J 3/16 20060101 H04J003/16; H04J 11/00 20060101
H04J011/00 |
Claims
1. (canceled)
2. An apparatus of a user equipment (UE) configured for operation
in a fifth-generation system (5GS), the apparatus comprising:
processing circuitry; and memory coupled to the processing
circuitry, wherein to determine a physical downlink control channel
(PDCCH) assignment in the 5GS, the processing circuitry is
configured to: decode a system information block (SIB), the SIB
indicating a PDCCH search space for acquisition of a PDCCH; monitor
a number of PDCCH candidates to detect a downlink control
information (DCI) format, the number of PDCCH candidates based on
the PDCCH search space; if the DCI format is detected, decode the
DCI format to determine scheduling for a physical downlink shared
channel (PDSCH); and decode the PDSCH, wherein the memory is
configured to store the SIB.
3. The apparatus of claim 2, wherein the SIB indicates whether the
PDCCH search space comprises common search space or UE-specific
search space.
4. The apparatus of claim 2, wherein to monitor the number of PDCCH
candidates, the processing circuitry is configured to decode each
PDCCH candidate according to the monitored DCI format
5. The apparatus of claim 2, wherein the processing circuitry is
configured to decode radio-resource control (RRC) signalling for
configuration information for acquiring the PDCCH.
6. The apparatus of claim 2 wherein the SIB is received in a master
information block (MIB).
7. The apparatus of claim 2 wherein the processing circuitry is
configured to decode each PDCCH candidate according to a monitored
DCI format.
8. The apparatus of claim 2 wherein to determine the PDCCH
assignment, the processing circuitry is configured to monitor the
number of PDCCH candidates per slot to detect the DCI format.
9. The apparatus of claim 2 wherein the PDCCH candidates start at
symbol 0, symbol 1, or symbol 2 of a slot.
10. The apparatus of claim 2, wherein the number of the PDCCH
candidates to be monitored are based on an aggregation level of
control channel resources.
11. The apparatus of claim 2, wherein the processing circuitry
comprises a baseband processor.
12. A non-transitory computer-readable storage medium that stores
instructions for execution by processing circuitry of a user
equipment (UE) configured for operation in a fifth-generation
system (5GS), wherein to determine a physical downlink control
channel (PDCCH) assignment the 5GS, wherein to determine a physical
downlink control channel (PDCCH) assignment in the 5GS, the
instructions configured the processing circuitry to: decode a
system information block (SIB), the SIB indicating a PDCCH search
space for acquisition of a PDCCH; monitor a number of PDCCH
candidates to detect a downlink control information (D format, the
number of PDCCH candidates based on the PDCCH search space; if the
DCI format is detected, decode the DCI format to determine
scheduling for a physical downlink shared channel (PDSCH); and
decode the PDSCH.
13. The non-transitory computer-readable storage medium of claim
12, wherein the SIB indicates whether the PDCCH search space
comprises common search space or UE-specific search space.
14. The non-transitory computer-readable storage medium of claim
12, wherein to monitor the number of PDCCH candidates, the
processing circuitry is configured to decode each PDCCH candidate
according to the monitored DCI format
15. The non-transitory computer-readable storage medium of claim
12, wherein the processing circuitry is configured to decode
radio-resource control (RRC) signalling for configuration
information for acquiring the PDCCH.
16. The non-transitory computer-readable storage medium of claim 12
wherein the SIB is received in a master information block
(MIB).
17. The non-transitory computer-readable storage medium of claim 12
wherein the processing circuitry is configured to decode each PDCCH
candidate according to a monitored DCI format.
18. An apparatus of a base station configured for operation in a
fifth-generation system (5GS), the apparatus comprising: processing
circuitry; and memory, wherein the processing circuitry is
configured to: encode a system information block (SIB) for
transmission to a User Equipment (UE), the SIB indicating a
physical downlink control channel (PDCCH) search space for
acquisition of the PDCCH by the UE, the PDCCH search space
indicating a number of PDCCH candidates for the UE to monitor to
detect a DCI format; encode a PDCCH for transmission, the PDCCH
encoded to include a DCI format for detection by the UE within one
or more of the PDCCH candidates, the DCI format including
scheduling for a physical downlink shared channel (PDSCH); and
encode the PDSCH for transmission in according with the scheduling,
wherein the memory is configured to store the SIB.
19. The apparatus of claim 18 wherein the PDCCH and the PDSCH are
encoded for transmission in a same downlink subframe.
20. The apparatus of claim 18 wherein PDSCH is encoded for
transmission in a downlink subframe that includes the PDCCH
candidates.
21. The apparatus of claim 18 wherein the PDSCH is multiplexed with
the PDCCH candidates in downlink subframes.
22. The apparatus of claim 18, wherein the PDCCH candidates have a
maximum duration of three orthogonal frequency division
multiplexing (OFDM) symbols and start at symbol 0, symbol 1, or
symbol 2 of a slot, and wherein a bandwidth of the PDCCH candidates
is indicated in the SIB, the bandwidth being less than a system
channel bandwidth.
Description
CLAIM OF PRIORITY
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 15/568,746, filed Oct. 23, 2017, which is a
U.S. National Stage Application under 35 U.S.C. 371 from
International Application No. PCT/US2015/065093, filed Dec. 10,
2015, now published as WO 2016/186699 A1, which claims the benefit
of priority to U.S. Provisional Patent Application No. 62/165,115,
filed May 21, 2015, entitled "A NOVEL PHYSICAL DOWNLINK CONTROL
CHANNEL DESIGN FOR 5G", each of which is incorporated by reference
herein in its entirety.
TECHNICAL FIELD
[0002] Embodiments pertain to wireless communications. Some
embodiments relate to cellular communication networks including
3GPP (Third Generation Partnership Project) networks, 3GPP LTE
(Long Term Evolution) networks, and 3GPP LTE-A (LTE Advanced)
networks, although the scope of embodiments is not limited in this
respect. Some embodiments pertain to 5G communications. Some
embodiments relate to control channel design.
BACKGROUND
[0003] Control channels transmit control information to users in
wireless communication networks. Control channels include
sufficient resources to transmit control information to a wide
variety of narrowband and wideband devices, while maintaining the
flexibility to support dynamic allocation of sub-bands for
different applications and services. The design of control channels
has been an ongoing process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a functional diagram of a 3GPP network in
accordance with some embodiments;
[0005] FIG. 2 illustrates a physical downlink control channel
(PDCCH) and enhanced PDCCH (ePDCCH) in accordance with 3GPP LTE
specifications;
[0006] FIG. 3 illustrates a proposed PDCCH design in accordance
with some embodiments;
[0007] FIGS. 4A and 4B illustrate schemes for multiplexing a
proposed PDCCH and a physical downlink shared channel (PDSCH) in
accordance with some embodiments;
[0008] FIGS. 5A and 5B illustrate frequency division multiplexing
(FDM) of a proposed PDCCH design and a PDSCH in accordance with
some embodiments;
[0009] FIGS. 6A and 6B illustrates time division multiplexing (TDM)
of a proposed PDCCH design and a PDSCH in accordance with some
embodiments;
[0010] FIG. 7 illustrates a first example Demodulation Reference
Symbol (DM-RS) pattern for transmission of a proposed PDCCH design
in accordance with some embodiments;
[0011] FIG. 8 illustrates resource mapping for the first DM-RS
pattern in accordance with various embodiments;
[0012] FIG. 9 illustrates a second example DM-RS pattern for
transmission of a proposed PDCCH design in accordance with various
embodiments;
[0013] FIG. 10 illustrates resource mapping for the second example
DM-RS pattern in accordance with various embodiments;
[0014] FIGS. 11A-11D illustrate TDM-based DM-RS patterns in
accordance with various embodiments;
[0015] FIGS. 12A-12E illustrates still further example DM-RS
patterns in accordance with various embodiments;
[0016] FIG. 13 is a functional diagram of a User Equipment (UE) in
accordance with some embodiments;
[0017] FIG. 14 is a functional diagram of an Evolved Node-B (eNB)
in accordance with some embodiments; and
[0018] FIG. 15 is a block diagram illustrating components of a
machine, according to some example embodiments, able to read
instructions from a machine-readable medium and perform any one or
more of the methodologies discussed herein, according to aspects of
the disclosure.
DETAILED DESCRIPTION
[0019] The following description and the drawings sufficiently
illustrate specific embodiments to enable those skilled in the art
to practice them. Other embodiments can incorporate structural,
logical, electrical, process, and other changes. Portions and
features of some embodiments can be included in, or substituted
for, those of other embodiments. Embodiments set forth in the
claims encompass all available equivalents of those claims.
[0020] FIG. 1 is a functional diagram of a 3GPP network in
accordance with some embodiments. The network comprises a radio
access network (RAN) (e.g., as depicted, the E-UTRAN or evolved
universal terrestrial radio access network) 100 and the core
network 120 (e.g., shown as an evolved packet core (EPC)) coupled
together through an S1 interface 115. For convenience and brevity
sake, only a portion of the core network 120, as well as the RAN
100, is shown.
[0021] The core network 120 includes a mobility management entity
(MME) 122, a serving gateway (serving GW) 124, and packet data
network gateway (PDN GW) 126. The RAN 100 includes Evolved Node-B's
(eNBs) 104 (which can operate as base stations) for communicating
with User Equipment (UE) 102.
[0022] The eNBs 104 can include macro eNBs and low power (LP) eNBs.
In accordance with some embodiments, the eNB 104 can receive uplink
data packets from the UE 102 on a Radio Resource Control (RRC)
connection between the eNB 104 and the UE 102. The eNB 104 can
transmit an RRC connection release message to the UE 102 to
indicate a transition of the UE 102 to an RRC idle mode for the RRC
connection. The eNB 104 can further receive additional uplink data
packets according to the stored context information.
[0023] The MME 122 manages mobility aspects in access such as
gateway selection and tracking area list management. The serving GW
124 terminates the interface toward the RAN 10, and routes data
packets between the RAN 100 and the core network 120. In addition,
it can be a local mobility anchor point for inter-eNB handovers and
also can provide an anchor for inter-3GPP mobility. Other
responsibilities may include lawful intercept, charging, and some
policy enforcement. The serving GW 124 and the MME 122 can be
implemented in one physical node or separate physical nodes. The
PDN GW 126 terminates an SGi interface toward the packet data
network (PDN). The PDN GW 126 routes data packets between the EPC
120 and the external PDN, and can be a key node for policy
enforcement and charging data collection. It can also provide an
anchor point for mobility with non-LTE accesses. The external PDN
can be any kind of IP network, as well as an IP Multimedia
Subsystem (IMS) domain. The PDN GW 126 and the serving GW 124 can
be implemented in one physical node or separated physical nodes.
Furthermore, the MME 122 and the Serving GW 124 can be collapsed
into one physical node in which case the messages will need to be
transferred with one less hop.
[0024] The eNBs 104 (macro and micro) terminate the air interface
protocol and can be the first point of contact for a UE 102. In
some embodiments, an eNB 104 can fulfill various logical functions
for the RAN 100 including but not limited to RNC (radio network
controller functions) such as radio bearer management, uplink and
downlink dynamic radio resource management and data packet
scheduling, and mobility management. In accordance with
embodiments, UEs 102 can be configured to communicate Orthogonal
Frequency Division Multiplexing (OFDM) communication signals with
an eNB 104 over a multicarrier communication channel in accordance
with an Orthogonal Frequency Division Multiple Access (OFDMA)
communication technique. The OFDM signals can comprise a plurality
of orthogonal subcarriers.
[0025] The S1 interface 115 is the interface that separates the RAN
100 and the EPC 120. It is split into two parts: the S1-U, which
carries traffic data between the eNBs 104 and the serving GW 124,
and the S1-MME, which is a signaling interface between the eNBs 104
and the MME 122. The X2 interface is the interface between eNBs
104. The X2 interface comprises two parts, the X2-C and X2-U. The
X2-C is the control plane interface between the eNBs 104, while the
X2-U is the user plane interface between the eNBs 104.
[0026] With cellular networks, LP cells are typically used to
extend coverage to indoor areas where outdoor signals do not reach
well, or to add network capacity in areas with very dense phone
usage, such as train stations. As used herein, the term low power
(LP) eNB refers to any suitable relatively low power eNB for
implementing a narrower cell (narrower than a macro cell) such as a
femtocell, a picocell, or a micro cell. Femtocell eNBs are
typically provided by a mobile network operator to its residential
or enterprise customers. A femtocell is typically the size of a
residential gateway or smaller and generally connects to the user's
broadband line. Once plugged in, the femtocell connects to the
mobile operator's mobile network and provides extra coverage in a
range of typically 30 to 50 meters for residential femtocells.
Thus, a LP eNB might be a femtocell eNB since it is coupled through
the PDN GW 126. Similarly, a picocell is a wireless communication
system typically covering a small area, such as in-building
(offices, shopping malls, train stations, etc.), or more recently
in-aircraft. A picocell eNB can generally connect through the X2
link to another eNB such as a macro eNB through its base station
controller (BSC) functionality. Thus, LP eNB can be implemented
with a picocell eNB since it is coupled to a macro eNB via an X2
interface. Picocell eNBs or other LP eNBs can incorporate some or
all functionality of a macro eNB. In some cases, this can be
referred to as an access point base station or enterprise
femtocell.
[0027] In some embodiments, a downlink resource grid can be used
for downlink transmissions from an eNB 104 to a UE 102, while
uplink transmission from the UE 102 to the eNB 104 can utilize
similar techniques. The grid can be a time-frequency grid, called a
resource grid or time-frequency resource grid, which is the
physical resource in the downlink in each slot. Such a
time-frequency plane representation is a common practice for OFDM
systems, which makes it intuitive for radio resource allocation.
Each column and each row of the resource grid correspond to one
OFDM symbol and one OFDM subcarrier, respectively. The duration of
the resource grid in the time domain corresponds to one slot in a
radio frame. The network frame structure and particular frame
information (e.g., frame number) can depend on the Radio Access
Technology (RAT) being used by the UE to connect with the network.
For example, communication over an LTE network can be divided into
10 ms frames, each of which can contain ten 1 ms subframes. Each
subframe of the frame, in turn, can contain two slots of 0.5
ms.
[0028] The smallest time-frequency unit in a resource grid is
denoted as a resource element (RE). Each resource grid comprises a
number of resource blocks (RBs), which describe the mapping of
certain physical channels to resource elements. Each resource block
comprises a collection of resource elements and in the frequency
domain and can represent the smallest quanta of resources that
currently can be allocated. There are several different physical
downlink channels that are conveyed using such resource blocks.
With particular relevance to this disclosure, two of these physical
downlink channels are the physical downlink shared channel and the
physical downlink control channel. The design of these channels,
particularly the physical downlink control channel, has been an
ongoing process.
[0029] The physical downlink shared channel (PDSCH) carries user
data and higher-layer signaling to a UE 102 (FIG. 1). The physical
downlink control channel (PDCCH) carries information about the
transport format and resource allocations related to the PDSCH
channel, among other things. An enhanced PDCCH (ePDCCH) is also
provided in some revisions of the 3GPP LTE.
[0030] FIG. 2 illustrates a PDCCH and ePDCCH in accordance with
3GPP LTE specifications. A legacy PDCCH 200 spans up to three OFDM
symbols (or four OFDM symbols if the system bandwidth is 1.4 MHz)
at the start 202 of a subframe. Multiple PDCCHs can be transmitted
in a downlink control region of a subframe. Given that the PDCCH
200 can only occupy up to three or four OFDM symbols in a subframe,
a limited number of Downlink Control Information (DCI) messages can
be transmitted per subframe, which can limit the capacity of the
control channel. The problem becomes even more pronounced with
support of cross carrier scheduling in systems that support carrier
aggregation (CA). Additionally, because the PDCCH 200 occupies the
full system bandwidth, systems can be unable to flexibly support
dynamic allocation of sub-band for different applications and
services. For instance, in 3GPP LTE Rel-13, a machine type
communication (MTC) region (not shown in FIG. 2) is defined after
the legacy PDCCH region 200 to provide coexistence of legacy LTE
UEs and low cost MTC devices with 1.4 MHz system bandwidth.
[0031] To overcome the limitation of PDCCH, 3GPP LTE Rel. 11
introduced ePDCCH 204 to increase the control channel capacity. In
order to coexist on the same carrier with legacy UEs and to prevent
interference with legacy control channels (e.g., PDCCH 200), the
ePDCCH 204 is transmitted after the legacy PDCCH 200 control
region. Further, ePDCCH and PDSCH are multiplexed in a
frequency-division multiplexing (FDM) manner (not shown in FIG. 2)
to minimize the interference to data channel transmission. The FDM
based multiplexing scheme can also allow frequency-selective
scheduling based on the channel state information (CSI) feedback
from a UE, thereby leading to superior performance for ePDCCH.
[0032] However, one of the drawbacks for ePDCCH is reduced
processing time budget for PDSCH decoding. Given that ePDCCH 204
spans the remaining symbols in one subframe after the PDCCH region
200, a UE device would typically have to wait several hundred
microseconds after the end of the subframe to complete the ePDCCH
decoding, giving less time for PDSCH decoding and generation of the
hybrid automatic repeat request acknowledgment (HARQ-ACK)
feedback.
[0033] To overcome these and other shortcomings, embodiments
provide a design for PDCCH for systems that follows a design
principle of mixed TDM and FDM mode, which can exploit the benefits
using TDM (similar to PDCCH) and FDM (similar to ePDCCH)
multiplexing schemes.
Proposed xPDCCH Design
[0034] FIG. 3 illustrates a proposed PDCCH (e.g., an "xPDCCH")
design in accordance with some embodiments. More specifically,
xPDCCH 300 spans an initial number of OFDM symbols within one
transmission time interval (TTI), and occupies N PRBs within the
system bandwidth, wherein N is less than the number of PRBs within
the system bandwidth). In the frequency domain, contiguous or
non-contiguous resources can be allocated for xPDCCH, for example,
a second xPDCCH region 302 can be non-contiguous with xPDCCH
300.
[0035] Systems and apparatuses in accordance with various
embodiments, can transmit xPDCCH in localized mode or in
distributed mode. Localized transmission of xPDCCH can allow
closed-loop frequency dependent scheduling, for enhanced or
improved performance. Distributed transmission of xPDCCH can
exploit benefits of frequency diversity, which, among other
features, can enhance or facilitate scheduling of common control
messages for a group of UEs in a network.
[0036] Embodiments can assist operators in improving the processing
budget for physical downlink shared channel (xPDSCH) decoding.
Embodiments allow dynamic allocation of sub-bands for various
applications and partitions, and embodiments support
frequency-selective scheduling, and frequency domain inter-cell
interference cancellation (ICIC). Operators can further experience
more efficient support of MU-MIMO to increase the control channel
capacity.
[0037] Referring again to FIG. 3, in embodiments, the shared
channel 304 can be transmitted after the control region (e.g., from
the K+1 symbol, where K is the number of symbols in the control
region). In an example embodiment, the control channel spans the
first slot within the TTI, which enables cross-slot scheduling for
the shared channel.
[0038] In another embodiment, the xPDSCH can span a full subframe.
FIGS. 4A and 4B illustrate schemes for multiplexing a proposed
PDCCH and a physical downlink shared channel (PDSCH) in accordance
with some embodiments.
[0039] Referring to FIG. 4A, the xPDSCH 400 can be transmitted on
PRBs which are not occupied by the xPDCCH 402 transmission. In
another example as shown in FIG. 4B, the xPDSCH 400 can be
partially or fully overlapped with the xPDCCH 402. If the xPDCCH
402 is associated with the xPDSCH 400 with which it overlaps, the
xPDSCH 400 is not mapped to REs carrying the associated xPDCCH 402.
Rather, the xPDSCH 400 is rate matched around these resources. If
the xPDSCH 400 is semi-persistently scheduled without a
corresponding xPDCCH 402, a UE (e.g., UE 102, FIG. 1) can continue
to rate match around the resources 404 to allow a scheduler at the
eNB (e.g., the eNB 104, FIG. 1) to dynamically transmit the xPDCCH
402 in these resources 404 to other UEs. Alternatively, the xPDSCH
400 will not be rate matched when the xPDSCH 400 is
semi-persistently scheduled without a corresponding xPDCCH 402.
[0040] The configuration information for the xPDCCH can be included
in DCI messages or signaled via UE-specific dedicated RRC
signaling. However, the size of DCI messages can become overly
large, resulting in reduced or worsened performance.
[0041] In another embodiment, xPDSCH is scheduled to be transmitted
in a subsequent subframe (e.g., the next subframe) after which
xPDCCH was transmitted. This cross-subframe scheduling may pose
certain constraints on the processing time for xPDSCH decoding.
This issue can be resolved by extending the HARQ timing. For
example, the gap between xPDCCH and ACK/NACK feedback can be
extended from 4 subframes to 5 subframes.
[0042] An eNB (e.g., eNB 104) or other network-side entity can
configure xPDCCH by providing various parameters to user devices
(e.g., UE 102). The configurations of xPDCCH transmission resources
can be independent for the common search space and the UE-specific
search space. These parameters can include, in various embodiments,
time domain information, frequency domain information, or any
combination thereof. Time domain information can include the number
of OFDM symbols (K) provided for xPDCCH, or a bitmap specifying
whether the xPDCCH is configured to be transmitted in the
corresponding subframe, and this pattern of xPDCCH can be repeated
with a periodicity. As an example, given a parameter
subframeBitMap="0011000011" xPDCCH transmission will occur at
subframe 2, 3, 8 and 9, in each frame.
[0043] Frequency domain information can include the PRB index and
information regarding localized or distributed mode. The resource
or PRB index can be configured in a contiguous or non-contiguous
manner. Additionally, one UE can be configured with one or more
transmission modes. For example, one UE 102 can be configured with
2 localized transmission modes, a second UE 102 can be configured
with 1 localized mode and 1 distributed mode, and a third UE 102
can be configured with 1 distributed mode.
[0044] In one embodiment, xPDCCH can be transmitted using PRB
bundling, to improve the channel estimation performance. More
specifically, when PRB bundling is employed, the same beamforming
weight is applied on the bundled PRBs for the transmission of the
xPDCCH. When the xPDCCH and the xPDSCH for the same UE exists in
different PRBs of the same PRB bundling, PRB bundling can be
applied to improve the channel estimation performance of xPDCCH and
xPDSCH. The PRB bundling size can be predefined by 3GPP
specification, or configured by a higher layer. Further, the PRB
bundling size can be determined based on the system bandwidth. If
PRB bundling is applied, the eNB 104 can specify or configure the
bundled PRB index in the frequency domain.
[0045] In some embodiments, the resource allocation for the
transmission of xPDCCH can be predefined. For example, the number
of OFDM symbols (K) used for the transmission of xPDCCH can be
predefined in the specification. In another example, xPDCCH can be
allocated at the edge of the system bandwidth, thereby exploiting
key benefits of frequency diversity. At least these embodiments may
be used when the xPDCCH is used to schedule common control
messages, (e.g., SIB, paging, and random access response (RAR)
messages).
[0046] In some embodiments, the resource allocation for the
transmission of xPDCCH can be configured in the master information
block (MIB) or a system information block (SIB0. In one example,
the resource allocation configuration for xPDCCH used to schedule
the SIB1 transmission is indicated in the MIB, and that for xPDCCH
used to schedule other SIB transmission can be indicated in the SIB
1. As a further example, the resource allocation for the xPDCCH
used to schedule paging/RAR transmission can be indicated in the
SIB2. However, embodiments are not limited to usage of any
particular SIB for indicating xPDCCH allocations.
[0047] In some embodiments, the resource allocation for the
transmission of xPDCCH can be configured via UE-specific dedicated
signaling. These embodiments can also be applied in carrier
aggregation use cases, wherein the xPDCCH resource allocation at
the secondary cell (SCell) can be configured in the UE-specific RRC
signaling from the primary cell (PCell). In still other
embodiments, the xPDCCH resource allocation can be indicated in a
dedicated channel or signal. For example, the number of OFDM
symbols (K) used for the transmission of xPDCCH can be indicated
via Physical Control Format Indicator channel (PCFICH) as defined
by 3GPP specifications.
[0048] In some embodiments, the xPDCCH resource allocation for
common control messages may be transparent between eNB and UE
without any definition. The PRB starting index for common control
message may be obtained based on a hash function which depends on
the cell ID and subframe index, so that the inter-cell interference
for the common control message may be reduced. An active UE may
search the common control message from a corresponding xPDCCH in
each subframe.
[0049] In some embodiments, the resource allocation for the
transmission of xPDCCH may be defined by the PDSCH message with a
control element indicating the xPDCCH resource index, which may
define the PRB starting index, bundling size and scramble ID in
Demodulation reference symbol (DM-RS). In another embodiment, the
resource allocation for the transmission of xPDCCH may depend on
the subframe. For example, the network can configure a subset of
subframes for Multimedia Broadcast/Multicast Services (MBMS). In
these subframes, the eNB 104 can transmit multicast data to a
plurality of users. In order to allow scheduling of downlink or
uplink transmissions in subsequent subframes, the system bandwidth
can be divided into a MBMS region and a non-MBMS region. In order
to not fragment the MBMS region, the non-MBMS region may be at
either or both edges of the system bandwidth. xPDCCH transmission
can occur in MBMS-dedicated subframes in the non-MBMS region to
transmit uplink grants or downlink grants for cross-subframe
scheduled xPDSCH transmissions. In addition, if the eNB does not
transmit MBMS data in the MBMS region of an MBMS dedicated
subframe, the eNB can dynamically use an xPDCCH transmitted in the
non-MBMS region to schedule xPDSCH transmissions in the MBMS region
of the same subframe. This avoids blind detection of an xPDCCH in
the MBMS region. Accordingly, the DCI carried on the xPDCCH in the
non-MBMS region must convey to the UE if the grant applies to the
MBMS-region in the current subframe or if the grant is a
cross-subframe scheduling grant. In one embodiment, the DCI
contains a flag indicating whether the grant applies to the current
or a subsequent subframe. In another embodiment a new DCI format is
transmitted on the xPDCCH in the non-MBMS region to schedule xPDSCH
in the MBMS-region of the same subframe.
Variants on the xPDCCH Design
[0050] Various xPDCCH configurations and allocations can be
provided, as will be described in further detail below. For
example, in at least some embodiments illustrated in FIGS. 5A and
5B, xPDCCH spans one full subframe and the xPDCCH and xPDSCH are
multiplexed in a FDM manner. As described earlier herein, xPDSCH
can be transmitted in different PRBs from the xPDCCH (FIG. 5A) or
xPDSCH can be partially or fully overlapped with xPDCCH
transmission. Further, cross-subframe scheduling may be applied to
reduce the IQ buffer size as shown in FIG. 5B.
[0051] In other embodiments, shown in FIGS. 6A and 6B, xPDCCH spans
the first K OFDM symbols within one TTI, and occupies the full
system bandwidth. Further, the xPDCCH and xPDSCH are multiplexed in
a TDM manner. As described earlier herein, xPDSCH can be
transmitted after the xPDCCH region as shown in FIG. 5A or xPDSCH
can be partially overlapped with the transmission of xPDCCH as
shown in FIG. 5B Further, cross-subframe scheduling may be
applied.
Resource Mapping for xPDCCH
[0052] In current LTE specifications, an ePDCCH is transmitted
using one or more enhanced control channel element (eCCE)s, where
an eCCE includes four or eight enhanced resource element group
(eREG)s. There are 16 eREGs in a PRB pair, where each eREG
typically includes nine resource elements (RE)s.
[0053] In FDM-based embodiments or in mixed TDM/FDM embodiments
described earlier herein, resource mapping of xPDCCH can be
implemented in various ways. In various embodiments, proposed REG
(e.g., "xREG") can be defined based on a DM-RS pattern.
[0054] FIG. 7 illustrates a first example DM-RS pattern for
transmission of xPDCCH in accordance with some embodiments. In the
illustrated example, the DM-RS is transmitted in the OFDM symbol #2
and #3 in each slot within one TTI. Based on the DM-RS pattern
shown in FIG. 7, resource mapping of the xREG and xREG group can be
defined as shown in FIG. 8. Note that the xREG indices are
sequentially mapped to REs first in a frequency manner, and then in
a time manner within one PRB pair, excluding the DM-RS. 16 xREGs
(numbered 0-16 in FIG. 8) are defined (this is similar to current
LTE specifications defining 16 REGs), where each xREG consists of 9
REs within one PRB pair. 4 xREG groups are further defined, where
each xREG group consists of 4 xREGs.
[0055] The resource mapping of xREG group can be defined as follows
(xREG groups #0 and 1 are illustrated in FIG. 8): xREG group #0
{xREG #0, 4, 8, 12}; xREG group #1 {xREG #1, 5, 9, 13}; xREG group
#2 {xREG #2, 6, 10, 14}; and xREG group #3 {xREG #3, 7, 11,
15}.
[0056] xCCE may consist of either 4 or 8 xREGs depending on the
available REs allocated for the xPDCCH transmission. In the case
where xPDCCH follows the design principle of a mixed TDM and FDM
mode (as shown in FIG. 3), xCCE may consist of 8 xREGs or 2 xREG
groups. For instance, one xCCE may combine xREG group #0 and #2
while another xCCE may combine xREG group #1 and #3.
[0057] If xPDCCH spans a full subframe as shown in FIGS. 5A and 5B,
xCCE may consist of 4 xREGs or 1 xREG group. For instance, xCCE #0
may use xREG group #0; xCCE #1 may use xREG group #1; xCCE #2 may
use xREG group #2 and xCCE #3 may use xREG group #3.
[0058] In another example, the DM-RS pattern follows a scattered
structure, which can provide near-optimal channel estimation
performance. FIG. 9 illustrates the DM-RS pattern according to at
least these embodiments.
[0059] In another example, the DM-RS pattern for xPDCCH may be
similar to cell-specific RS, by which a transmit diversity MIMO
mode may be used. In at least these examples, the xPDCCH with
common messages may have improved performance because several UEs
may need to receive common messages at the same time. FIG. 10
illustrates resource mapping for this DM-RS pattern in accordance
with various embodiments. In this example, the xREG and xREG group
can follow similar patterns and design principles as described
above with reference to FIG. 8, and xREG groups can be defined
similarly as described above. Similar principles can be extended
and applied for other DM-RS patterns.
[0060] Unlike other available control channels (e.g., ePDCCH) which
use per-RE cyclic beamforming, in the design of xPDCCH according to
various embodiments, per-PRB pair beamforming can be applied to
allow frequency dependent scheduling. When the aggregation level is
greater than 4, a single antenna port is associated with
transmission of xPDCCH in one PRB. Alternatively, some embodiments
can apply the same precoder for 2 antenna ports within one PRB to
improve the channel estimation performance.
[0061] For embodiments in which xPDCCH and xPDSCH are TDM, (FIGS.
6A and 6B), xPDCCH spans the first K OFDM symbols and occupies the
full system bandwidth. FIGS. 11A-11D and 12A-12E illustrate the
examples of potential DM-RS patterns for xPDCCH transmission in
accordance with various embodiments with K=2. In FIGS. 11A-11D, the
DM-RS overhead is 2/3, 1/2, 1/3 and 1/4, respectively. Note that in
the examples as shown herein, DM-RS positions for the first and
second OFDM symbols are different. However, embodiments are not
limited thereto and embodiments can include examples in which the
DM-RS positions are the same across multiple OFDM symbols.
[0062] At least because analog beamforming can be applied for the
transmission of xPDCCH, some systems in accordance with various
embodiments can multiplex multiple users in a TDM, FDM or
spatial-division multiplexing (SDM) manner or a combination of the
above. Further, different users may be allocated with different
amounts of resources depending on channel conditions or other
factors. In one multiplexing scheme (e.g., SDM), xPDCCH for two
different UEs can be transmitted in the same OFDM symbol and at
full system bandwidth, but separated using different beamforming
weights. In a second multiplexing scheme (e.g., FDM), the xPDCCH
for two different users can be transmitted in the same OFDM symbol
and with the same beamforming weight, but separated using different
REs. In yet another multiplexing scheme (e.g., TDM), the xPDCCH for
two different users can be transmitted in different OFDM symbols,
using the same or different beamforming weights and resources.
However, it will be appreciated that embodiments are not limited to
these combinations of multiplexing.
[0063] In one embodiment, xPDCCH resource mapping may follow the
design principle for PDCCH. This option may be suitable for the
DM-RS pattern in which 4 REs may form one xREG as defined for PDCCH
resource mapping. In another embodiment, different numbers of REs
may form one xREG depending on the DM-RS pattern. For instance, for
the DM-RS pattern as shown in FIG. 11D, 6 REs may be group in one
xREG. Then one xCCE may occupy 6 xREGs so that the total number of
REs for one xCCE is 36.
[0064] To facilitate the MU-MIMO for the transmission of xPDCCH,
antenna ports for different users may be derived as a function of
C-RNTI for the localized transmission mode. Further, the scrambling
seed for the DM-RS sequence can be configured in a UE-specific
manner. When configured with different scrambling seeds, DM-RS
sequences for two UEs can be orthogonal, thereby enabling the
MUMIMO for the transmission of xPDCCH.
Apparatuses for Performing Various Embodiments
[0065] FIG. 13 is a functional diagram of a User Equipment (UE)
1300 in accordance with some embodiments. The UE 1300 may be
suitable for use as a UE 102 as depicted in FIG. 1. In some
embodiments, the UE 1300 may include application circuitry 1302,
baseband circuitry 1304, Radio Frequency (RF) circuitry 1306,
front-end module (FEM) circuitry 1308 and one or more antennas
1310, coupled together at least as shown. In some embodiments,
other circuitry or arrangements may include one or more elements
and/or components of the application circuitry 1302, the baseband
circuitry 1304, the RF circuitry 1306 and/or the FEM circuitry
1308, and may also include other elements and/or components in some
cases. As an example, "processing circuitry" may include one or
more elements and/or components, some or all of which may be
included in the application circuitry 1302 and/or the baseband
circuitry 1304. As another example, "transceiver circuitry" may
include one or more elements and/or components, some or all of
which may be included in the RF circuitry 1306 and/or the FEM
circuitry 1308. These examples are not limiting, however, as the
processing circuitry and/or the transceiver circuitry may also
include other elements and/or components in some cases.
[0066] In embodiments, the processing circuitry can configure the
transceiver circuitry to receive a control channel (e.g., PDCCH,
ePDCCH, xPDCCH, etc.), from an eNB (e.g., eNB 104, FIG. 1),
occupying an initial number of orthogonal frequency division
multiplexing (OFDM) symbols of a downlink subframe. As described
earlier herein, this initial number (e.g., "K"), is less than or
equal to the number of OFDM symbols in the downlink subframe. The
value for K can be received from the eNB in a MIB or SIB or through
RRC signaling as described earlier herein. In some embodiments, the
control channel can occupy greater than three, or greater than
four, initial OFDM symbols in a subframe. In some embodiments, the
control channel can occupy all OFDM symbols of a downlink slot at a
frequency or set of frequencies. In at least these embodiments, the
downlink shared channel can be FDM with the control channel. In
some embodiments, the downlink shared channel can occupy all OFDM
symbols of a downlink slot at a frequency or set of frequencies of
a resource block. In at least these embodiments, resources
allocated to the downlink shared channel can at least partially
overlap resources allocated for the control channel.
[0067] The control channel can occupy fewer than N PRBs of a system
bandwidth comprised of N PRBs. Alternatively, in at least some
embodiments, the control channel can occupy all N PRBs of a system
bandwidth comprised of N PRBs. The transceiver circuitry can
receive information from the eNB 104 indicating at least one PRB
index for at least one PRB in which the control channel information
is to be received. In embodiments, the control channel can occupy
two or more sets of PRBs within the system bandwidth.
[0068] The processing circuitry can configure the transceiver
circuitry to receive other channels such as a downlink shared
channel (e.g., PDSCH) from the eNB 104. The downlink shared channel
can be TDM with the control channel. The downlink shared channel
can additionally or alternatively be FDM with the control channel.
The processing circuitry can process the control channel and the
downlink shared channel according to any methods or criteria
described in standards for wireless communication.
[0069] The application circuitry 1302 may include one or more
application processors. For example, the application circuitry 1302
may include circuitry such as, but not limited to, one or more
single-core or multi-core processors. The processor(s) may include
any combination of general-purpose processors and dedicated
processors (e.g., graphics processors, application processors,
etc.). The processors may be coupled with and/or may include
memory/storage and may be configured to execute instructions stored
in the memory/storage to enable various applications and/or
operating systems to run on the system.
[0070] The baseband circuitry 1304 may include circuitry such as,
but not limited to, one or more single-core or multi-core
processors. The baseband circuitry 1304 may include one or more
baseband processors and/or control logic to process baseband
signals received from a receive signal path of the RF circuitry
1306 and to generate baseband signals for a transmit signal path of
the RF circuitry 1306. Baseband circuitry 1304 may interface with
the application circuitry 1302 for generation and processing of the
baseband signals and for controlling operations of the RF circuitry
1306. For example, in some embodiments, the baseband circuitry 1304
may include a second generation (2G) baseband processor 1304a,
third generation (3G) baseband processor 1304b, fourth generation
(4G) baseband processor 1304c, and/or other baseband processor(s)
1304d for other existing generations, generations in development or
to be developed in the future (e.g., fifth generation (5G), 6G,
etc.). The baseband circuitry 1304 (e.g., one or more of baseband
processors 1304a-d) may handle various radio control functions that
enable communication with one or more radio networks via the RF
circuitry 1306. The radio control functions may include, but are
not limited to, signal modulation/demodulation, encoding/decoding,
radio frequency shifting, etc. In some embodiments,
modulation/demodulation circuitry of the baseband circuitry 1304
may include Fast-Fourier Transform (FFT), precoding, and/or
constellation mapping/demapping functionality. In some embodiments,
encoding/decoding circuitry of the baseband circuitry 1304 may
include convolution, tail-biting convolution, turbo, Viterbi,
and/or Low Density Parity Check (LDPC) encoder/decoder
functionality. Embodiments of modulation/demodulation and
encoder/decoder functionality are not limited to these examples and
may include other suitable functionality in other embodiments.
[0071] In some embodiments, the baseband circuitry 1304 may include
elements of a protocol stack such as, for example, elements of an
evolved universal terrestrial radio access network (EUTRAN)
protocol including, for example, physical (PHY), media access
control (MAC), radio link control (RLC), packet data convergence
protocol (PDCP), and/or radio resource control (RRC) elements. A
central processing unit (CPU) 1304e of the baseband circuitry 1304
may be configured to run elements of the protocol stack for
signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some
embodiments, the baseband circuitry may include one or more audio
digital signal processor(s) (DSP) 1304f The audio DSP(s) 1304f may
be include elements for compression/decompression and echo
cancellation and may include other suitable processing elements in
other embodiments. Components of the baseband circuitry may be
suitably combined in a single chip, a single chipset, or disposed
on a same circuit board in some embodiments. In some embodiments,
some or all of the constituent components of the baseband circuitry
1304 and the application circuitry 1302 may be implemented together
such as, for example, on a system on a chip (SOC).
[0072] In some embodiments, the baseband circuitry 1304 may provide
for communication compatible with one or more radio technologies.
For example, in some embodiments, the baseband circuitry 1304 may
support communication with an evolved universal terrestrial radio
access network (EUTRAN) and/or other wireless metropolitan area
networks (WMAN), a wireless local area network (WLAN), a wireless
personal area network (WPAN). Embodiments in which the baseband
circuitry 1304 is configured to support radio communications of
more than one wireless protocol may be referred to as multi-mode
baseband circuitry.
[0073] RF circuitry 1306 may enable communication with wireless
networks using modulated electromagnetic radiation through a
non-solid medium. In various embodiments, the RF circuitry 1306 may
include switches, filters, amplifiers, etc. to facilitate the
communication with the wireless network. RF circuitry 1306 may
include a receive signal path which may include circuitry to
down-convert RF signals received from the FEM circuitry 1308 and
provide baseband signals to the baseband circuitry 1304. RF
circuitry 1306 may also include a transmit signal path which may
include circuitry to up-convert baseband signals provided by the
baseband circuitry 1304 and provide RF output signals to the FEM
circuitry 1308 for transmission.
[0074] In some embodiments, the RF circuitry 1306 may include a
receive signal path and a transmit signal path. The receive signal
path of the RF circuitry 1306 may include mixer circuitry 1306a,
amplifier circuitry 1306b and filter circuitry 1306c. The transmit
signal path of the RF circuitry 1306 may include filter circuitry
1306c and mixer circuitry 1306a. RF circuitry 1306 may also include
synthesizer circuitry 1306d for synthesizing a frequency for use by
the mixer circuitry 1306a of the receive signal path and the
transmit signal path. In some embodiments, the mixer circuitry
1306a of the receive signal path may be configured to down-convert
RF signals received from the FEM circuitry 1308 based on the
synthesized frequency provided by synthesizer circuitry 1306d. The
amplifier circuitry 1306b may be configured to amplify the
down-converted signals and the filter circuitry 1306c may be a
low-pass filter (LPF) or band-pass filter (BPF) configured to
remove unwanted signals from the down-converted signals to generate
output baseband signals. Output baseband signals may be provided to
the baseband circuitry 1304 for further processing. In some
embodiments, the output baseband signals may be zero-frequency
baseband signals, although this is not a requirement. In some
embodiments, mixer circuitry 1306a of the receive signal path may
comprise passive mixers, although the scope of the embodiments is
not limited in this respect. In some embodiments, the mixer
circuitry 1306a of the transmit signal path may be configured to
up-convert input baseband signals based on the synthesized
frequency provided by the synthesizer circuitry 1306d to generate
RF output signals for the FEM circuitry 1308. The baseband signals
may be provided by the baseband circuitry 1304 and may be filtered
by filter circuitry 1306c. The filter circuitry 1306c may include a
low-pass filter (LPF), although the scope of the embodiments is not
limited in this respect.
[0075] In some embodiments, the mixer circuitry 1306a of the
receive signal path and the mixer circuitry 1306a of the transmit
signal path may include two or more mixers and may be arranged for
quadrature downconversion and/or upconversion respectively. In some
embodiments, the mixer circuitry 1306a of the receive signal path
and the mixer circuitry 1306a of the transmit signal path may
include two or more mixers and may be arranged for image rejection
(e.g., Hartley image rejection). In some embodiments, the mixer
circuitry 1306a of the receive signal path and the mixer circuitry
1306a may be arranged for direct downconversion and/or direct
upconversion, respectively. In some embodiments, the mixer
circuitry 1306a of the receive signal path and the mixer circuitry
1306a of the transmit signal path may be configured for
super-heterodyne operation.
[0076] In some embodiments, the output baseband signals and the
input baseband signals may be analog baseband signals, although the
scope of the embodiments is not limited in this respect. In some
alternate embodiments, the output baseband signals and the input
baseband signals may be digital baseband signals. In these
alternate embodiments, the RF circuitry 1306 may include
analog-to-digital converter (ADC) and digital-to-analog converter
(DAC) circuitry and the baseband circuitry 1304 may include a
digital baseband interface to communicate with the RF circuitry
1306. In some dual-mode embodiments, a separate radio IC circuitry
may be provided for processing signals for each spectrum, although
the scope of the embodiments is not limited in this respect.
[0077] In some embodiments, the synthesizer circuitry 1306d may be
a fractional-N synthesizer or a fractional N/N+1 synthesizer,
although the scope of the embodiments is not limited in this
respect as other types of frequency synthesizers may be suitable.
For example, synthesizer circuitry 1306d may be a delta-sigma
synthesizer, a frequency multiplier, or a synthesizer comprising a
phase-locked loop with a frequency divider. The synthesizer
circuitry 1306d may be configured to synthesize an output frequency
for use by the mixer circuitry 1306a of the RF circuitry 1306 based
on a frequency input and a divider control input. In some
embodiments, the synthesizer circuitry 1306d may be a fractional
N/N+1 synthesizer. In some embodiments, frequency input may be
provided by a voltage controlled oscillator (VCO), although that is
not a requirement. Divider control input may be provided by either
the baseband circuitry 1304 or the application circuitry 1302
depending on the desired output frequency. In some embodiments, a
divider control input (e.g., N) may be determined from a look-up
table based on a channel indicated by the application circuitry
1302.
[0078] Synthesizer circuitry 1306d of the RF circuitry 1306 may
include a divider, a delay-locked loop (DLL), a multiplexer and a
phase accumulator. In some embodiments, the divider may be a dual
modulus divider (DMD) and the phase accumulator may be a digital
phase accumulator (DPA). In some embodiments, the DMD may be
configured to divide the input signal by either N or N+1 (e.g.,
based on a carry out) to provide a fractional division ratio. In
some example embodiments, the DLL may include a set of cascaded,
tunable, delay elements, a phase detector, a charge pump and a
D-type flip-flop. In these embodiments, the delay elements may be
configured to break a VCO period up into Nd equal packets of phase,
where Nd is the number of delay elements in the delay line. In this
way, the DLL provides negative feedback to help ensure that the
total delay through the delay line is one VCO cycle.
[0079] In some embodiments, synthesizer circuitry 1306d may be
configured to generate a carrier frequency as the output frequency,
while in other embodiments, the output frequency may be a multiple
of the carrier frequency (e.g., twice the carrier frequency, four
times the carrier frequency) and used in conjunction with
quadrature generator and divider circuitry to generate multiple
signals at the carrier frequency with multiple different phases
with respect to each other. In some embodiments, the output
frequency may be a LO frequency (fLO). In some embodiments, the RF
circuitry 1306 may include an IQ/polar converter.
[0080] FEM circuitry 1308 may include a receive signal path which
may include circuitry configured to operate on RF signals received
from one or more antennas 1310, amplify the received signals and
provide the amplified versions of the received signals to the RF
circuitry 1306 for further processing. FEM circuitry 1308 may also
include a transmit signal path which may include circuitry
configured to amplify signals for transmission provided by the RF
circuitry 1306 for transmission by one or more of the one or more
antennas 1310.
[0081] In some embodiments, the FEM circuitry 1308 may include a
TX/RX switch to switch between transmit mode and receive mode
operation. The FEM circuitry may include a receive signal path and
a transmit signal path. The receive signal path of the FEM
circuitry may include a low-noise amplifier (LNA) to amplify
received RF signals and provide the amplified received RF signals
as an output (e.g., to the RF circuitry 1306). The transmit signal
path of the FEM circuitry 1308 may include a power amplifier (PA)
to amplify input RF signals (e.g., provided by RF circuitry 1306),
and one or more filters to generate RF signals for subsequent
transmission (e.g., by one or more of the one or more antennas
1310. In some embodiments, the UE 1300 may include additional
elements such as, for example, memory/storage, display, camera,
sensor, and/or input/output (I/O) interface.
[0082] FIG. 14 is a functional diagram of an Evolved Node-B (eNB)
1400 in accordance with some embodiments. It should be noted that
in some embodiments, the eNB 1400 may be a stationary non-mobile
device. The eNB 1400 may be suitable for use as an eNB 104 as
depicted in FIG. 1. The eNB 1400 may include physical layer
circuitry 1402 and a transceiver 1405, one or both of which may
enable transmission and reception of signals to and from the UE
1300, other eNBs, other UEs or other devices using one or more
antennas 1401. As an example, the physical layer circuitry 1402 may
perform various encoding and decoding functions that may include
formation of baseband signals for transmission and decoding of
received signals. As another example, the transceiver 1405 may
perform various transmission and reception functions such as
conversion of signals between a baseband range and a Radio
Frequency (RF) range. Accordingly, the physical layer circuitry
1402 and the transceiver 1405 may be separate components or may be
part of a combined component. In addition, some of the
functionality described may be performed by a combination that may
include one, any or all of the physical layer circuitry 1402, the
transceiver 1405, and other components or layers. In some
embodiments, the transceiver 1405 can transmit, to a first UE
(e.g., UE 102, FIG. 1), a control channel occupying an initial
number of OFDM symbols of a downlink subframe. A value for the
initial number of OFDM symbols can be signaled to the UE in one or
more of a MIB or SIB, or within RRC signaling, or within a PCFICH,
by way of nonlimiting example.
[0083] The transceiver 1405 can transmit a downlink shared channel
to the first UE, wherein the downlink shared channel is time
division multiplexed (TDM) with the control channel. The
transceiver 1405 can then transmit the control channel to a second
UE. In some embodiments, the transceiver 1405 can transmit the
control channel to the first UE and to the second UE on the same
OFDM symbol using a full system bandwidth and different beamforming
weights. In some embodiments, the transceiver 1405 can transmit the
control channel to the first UE and to the second UE on the same
OFDM symbol and with same beamforming weight in a FDM fashion using
different REs.
[0084] The eNB 1400 may also include medium access control layer
(MAC) circuitry 1404 for controlling access to the wireless medium.
The eNB 1400 may also include processing circuitry 1406 and memory
1408 arranged to perform the operations described herein. The eNB
1400 may also include one or more interfaces 1410, which may enable
communication with other components, including other eNBs 104 (FIG.
1), components in the EPC 120 (FIG. 1) or other network components.
In addition, the interfaces 1410 may enable communication with
other components that may not be shown in FIG. 1, including
components external to the network. The interfaces 1410 may be
wired or wireless or a combination thereof.
[0085] The antennas 1310, 1401 may comprise one or more directional
or omnidirectional antennas, including, for example, dipole
antennas, monopole antennas, patch antennas, loop antennas,
microstrip antennas or other types of antennas suitable for
transmission of RF signals. In some multiple-input multiple-output
(MIMO) embodiments, the antennas 1310, 1401 may be effectively
separated to take advantage of spatial diversity and the different
channel characteristics that may result.
[0086] In some embodiments, the UE 1300 or the eNB 1400 may be a
mobile device and may be a portable wireless communication device,
such as a personal digital assistant (PDA), a laptop or portable
computer with wireless communication capability, a web tablet, a
wireless telephone, a smartphone, a wireless headset, a pager, an
instant messaging device, a digital camera, an access point, a
television, a wearable device such as a medical device (e.g., a
heart rate monitor, a blood pressure monitor, etc.), or other
device that may receive and/or transmit information wirelessly. In
some embodiments, the UE 1300 or eNB 1400 may be configured to
operate in accordance with 3GPP standards, although the scope of
the embodiments is not limited in this respect. Mobile devices or
other devices in some embodiments may be configured to operate
according to other protocols or standards, including IEEE 802.11 or
other IEEE standards. In some embodiments, the UE 1300, eNB 1400 or
other device may include one or more of a keyboard, a display, a
non-volatile memory port, multiple antennas, a graphics processor,
an application processor, speakers, and other mobile device
elements. The display may be an LCD screen including a touch
screen.
[0087] FIG. 15 illustrates a block diagram of an example machine
1500 upon which any one or more of the techniques (e.g.,
methodologies) discussed herein may perform. In alternative
embodiments, the machine 1500 may operate as a standalone device or
may be connected (e.g., networked) to other machines. In a
networked deployment, the machine 1500 may operate in the capacity
of a server machine, a client machine, or both in server-client
network environments. In an example, the machine 1500 may act as a
peer machine in peer-to-peer (P2P) (or other distributed) network
environment. The machine 1500 may be a UE, eNB, MME, personal
computer (PC), a tablet PC, a set-top box (STB), a personal digital
assistant (PDA), a mobile telephone, a smart phone, a web
appliance, a network router, switch or bridge, or any machine
capable of executing instructions (sequential or otherwise) that
specify actions to be taken by that machine. Further, while only a
single machine is illustrated, the term "machine" shall also be
taken to include any collection of machines that individually or
jointly execute a set (or multiple sets) of instructions to perform
any one or more of the methodologies discussed herein, such as
cloud computing, software as a service (SaaS), other computer
cluster configurations.
[0088] Examples, as described herein, may include, or may operate
on, logic or a number of components, modules, or mechanisms.
Modules are tangible entities (e.g., hardware) capable of
performing specified operations and may be configured or arranged
in a certain manner. In an example, circuits may be arranged (e.g.,
internally or with respect to external entities such as other
circuits) in a specified manner as a module. In an example, the
whole or part of one or more computer systems (e.g., a standalone,
client or server computer system) or one or more hardware
processors may be configured by firmware or software (e.g.,
instructions, an application portion, or an application) as a
module that operates to perform specified operations. In an
example, the software may reside on a machine readable medium. In
an example, the software, when executed by the underlying hardware
of the module, causes the hardware to perform the specified
operations.
[0089] Accordingly, the term "module" is understood to encompass a
tangible entity, be that an entity that is physically constructed,
specifically configured (e.g., hardwired), or temporarily (e.g.,
transitorily) configured (e.g., programmed) to operate in a
specified manner or to perform part or all of any operation
described herein. Considering examples in which modules are
temporarily configured, each of the modules need not be
instantiated at any one moment in time. For example, where the
modules comprise a general-purpose hardware processor configured
using software, the general-purpose hardware processor may be
configured as respective different modules at different times.
[0090] Software may accordingly configure a hardware processor, for
example, to constitute a particular module at one instance of time
and to constitute a different module at a different instance of
time.
[0091] Machine (e.g., computer system) 1500 may include a hardware
processor 1502 (e.g., a central processing unit (CPU), a graphics
processing unit (GPU), a hardware processor core, or any
combination thereof), a main memory 1504 and a static memory 1506,
some or all of which may communicate with each other via an
interlink (e.g., bus) 1508. The machine 1500 may further include a
display unit 1510, an alphanumeric input device 1512 (e.g., a
keyboard), and a user interface (UI) navigation device 1514 (e.g.,
a mouse). In an example, the display unit 1510, input device 1512
and UI navigation device 1514 may be a touch screen display. The
machine 1500 may additionally include a storage device (e.g., drive
unit) 1516, a signal generation device 1518 (e.g., a speaker), a
network interface device 1520, and one or more sensors 1521, such
as a global positioning system (GPS) sensor, compass,
accelerometer, or other sensor. The machine 1500 may include an
output controller 1528, such as a serial (e.g., universal serial
bus (USB), parallel, or other wired or wireless (e.g., infrared
(IR), near field communication (NFC), etc.) connection to
communicate or control one or more peripheral devices (e.g., a
printer, card reader, etc.).
[0092] The storage device 1516 may include a machine readable
medium 1522 on which is stored one or more sets of data structures
or instructions 1524 (e.g., software) embodying or utilized by any
one or more of the techniques or functions described herein. The
instructions 1524 may also reside, completely or at least
partially, within the main memory 1504, within static memory 1506,
or within the hardware processor 1502 during execution thereof by
the machine 1500. In an example, one or any combination of the
hardware processor 1502, the main memory 1504, the static memory
1506, or the storage device 1516 may constitute machine readable
media.
[0093] While the machine readable medium 1522 is illustrated as a
single medium, the term "machine readable medium" may include a
single medium or multiple media (e.g., a centralized or distributed
database, and/or associated caches and servers) configured to store
the one or more instructions 1524. When the machine 1500 operates
as a UE, the machine readable medium 1522 can instruct one or more
processors of the UE to receive, from an eNB, configuration
information indicating a number of OFDM symbols of a downlink
subframe that are to include a control channel; detect the control
channel in subsequent downlink transmissions from the eNB, starting
at an initial OFDM symbol for the downlink subframe; detect a
downlink shared channel at a subsequent OFDM symbol of the downlink
subframe, the subsequent OFDM symbol having been determined based
on the configuration information; and process the control channel
and the downlink shared channel.
[0094] The term "machine readable medium" may include any medium
that is capable of storing, encoding, or carrying instructions for
execution by the machine 1500 and that cause the machine 1500 to
perform any one or more of the techniques of the present
disclosure, or that is capable of storing, encoding or carrying
data structures used by or associated with such instructions.
Non-limiting machine readable medium examples may include
solid-state memories, and optical and magnetic media. Specific
examples of machine readable media may include: non-volatile
memory, such as semiconductor memory devices (e.g., Electrically
Programmable Read-Only Memory (EPROM), Electrically Erasable
Programmable Read-Only Memory (EEPROM)) and flash memory devices;
magnetic disks, such as internal hard disks and removable disks;
magneto-optical disks; Random Access Memory (RAM); and CD-ROM and
DVD-ROM disks. In some examples, machine readable media may include
non-transitory machine readable media. In some examples, machine
readable media may include machine readable media that is not a
transitory propagating signal.
[0095] The instructions 1524 may further be transmitted or received
over a communications network 1526 using a transmission medium via
the network interface device 1520 utilizing any one of a number of
transfer protocols (e.g., frame relay, internet protocol (IP),
transmission control protocol (TCP), user datagram protocol (UDP),
hypertext transfer protocol (HTTP), etc.). Example communication
networks may include a local area network (LAN), a wide area
network (WAN), a packet data network (e.g., the Internet), mobile
telephone networks (e.g., cellular networks), Plain Old Telephone
(POTS) networks, and wireless data networks (e.g., Institute of
Electrical and Electronics Engineers (IEEE) 802.11 family of
standards known as Wi-Fi.RTM., IEEE 802.16 family of standards
known as WiMax.RTM.), IEEE 802.15.4 family of standards, a Long
Term Evolution (LTE) family of standards, a Universal Mobile
Telecommunications System (UMTS) family of standards, peer-to-peer
(P2P) networks, among others. In an example, the network interface
device 1520 may include one or more physical jacks (e.g., Ethernet,
coaxial, or phone jacks) or one or more antennas to connect to the
communications network 1526. In an example, the network interface
device 1520 may include a plurality of antennas to wirelessly
communicate using at least one of single-input multiple-output
(SIMO), multiple-input multiple-output (MIMO), or multiple-input
single-output (MISO) techniques. In some examples, the network
interface device 1520 may wirelessly communicate using Multiple
User MIMO techniques. The term "transmission medium" shall be taken
to include any intangible medium that is capable of storing,
encoding or carrying instructions for execution by the machine
1500, and includes digital or analog communications signals or
other intangible medium to facilitate communication of such
software.
[0096] To better illustrate the apparatuses, systems, and methods
disclosed herein, a non-limiting list of examples is provided
herein:
[0097] In Example 1, an apparatus for a User Equipment (UE), the
apparatus comprising transceiver circuitry and hardware processing
circuitry, the hardware processing circuitry to configure the
transceiver circuitry to: receive a control channel, from an
Evolved Node-B (eNB), occupying an initial number of orthogonal
frequency division multiplexing (OFDM) symbols of a downlink
subframe, wherein the initial number is less than or equal to a
number of OFDM symbols in the downlink subframe; receive a downlink
shared channel from the eNB; and process the control channel and
the downlink shared channel.
[0098] In Example 2, the subject matter of Example 1 can optionally
include wherein the downlink shared channel is time division
multiplexed (TDM) with the control channel such that at least a
portion of the downlink shared channel is within a same
transmission time interval (TTI) as the control channel.
[0099] In Example 3, the subject matter of any of Examples 1-2 can
optionally include wherein the control channel occupies fewer
physical resource blocks (PRBs) than are in a system bandwidth.
[0100] In Example 4, the subject matter of any of Examples 1-3 can
optionally include wherein the downlink shared channel is
additionally frequency division multiplexed (FDM) with the control
channel.
[0101] In Example 5, the subject matter of any of Examples 1-3 can
optionally include wherein the hardware processing circuitry is
further to configure the transceiver circuitry to receive
information from the eNB indicating at least a value for the
initial number of OFDM symbols.
[0102] In Example 6, the subject matter of Example 5 can optionally
include wherein the information is received in a master information
block (MIB) or a system information block (SIB).
[0103] In Example 7, the subject matter of Example 5 can optionally
include wherein the information is received in UE-specific radio
resource control (RRC) signaling.
[0104] In Example 8, the subject matter of any of Examples 1-3 can
optionally include wherein the hardware processing circuitry is
further to configure the transceiver circuitry to receive
information from the eNB indicating at least one PRB index for at
least one PRB in which control channel information is to be
received, wherein the information further includes an indication of
whether control channel transmission is to be in a distributed mode
or a localized mode.
[0105] In Example 9, the subject matter of Example 3 can optionally
include wherein the control channel occupies all OFDM symbols of a
downlink slot at a frequency or set of frequencies; and the
downlink shared channel is frequency division multiplexed (FDM)
with the control channel.
[0106] In Example 10, the subject matter of Example 3 can
optionally include wherein the downlink shared channel occupies all
OFDM symbols of a downlink slot at a frequency or set of
frequencies of a resource block.
[0107] In Example 11, the subject matter of any of Examples 1-10
can optionally include wherein resources allocated to the downlink
shared channel at least partially overlap resources allocated for
the control channel.
[0108] In Example 12, the subject matter of any of Examples 1-11
can optionally include wherein the control channel occupies all
physical resource blocks (PRBs) of a system bandwidth.
[0109] In Example 13, the subject matter of Example 12 can
optionally include wherein resources allocated to the downlink
shared channel at least partially overlap resources allocated for
the control channel.
[0110] In Example 14, the subject matter of any of Examples 1-13
can optionally include wherein the control channel occupies two or
more sets of physical resource blocks (PRBs) within a system
bandwidth.
[0111] In Example 15, a computer-readable storage medium may stores
instructions for execution by one or more processors to perform
operations for communication by a User Equipment (UE), the
operations to configure the one or more processors to receive, from
an Evolved Node-B (eNB), configuration information indicating a
number of orthogonal frequency division multiplexing (OFDM) symbols
of a downlink subframe that are to include a control channel;
detect the control channel in subsequent downlink transmissions
from the eNB, starting at an initial OFDM symbol for the downlink
subframe; detect a downlink shared channel at a subsequent OFDM
symbol of the downlink subframe, the subsequent OFDM symbol having
been determined based on the configuration information; and process
the control channel and the downlink shared channel.
[0112] In Example 16, the subject matter of Example 15 can
optionally include instructions to receive a subframe bitmap from
the eNB, the subframe bitmap indicating which subframes of a
downlink frame are to include the control channel, wherein the
control channel occupies less than a full system bandwidth; and
detect the control channel in subframes indicated in the subframe
bitmap and refrain from detecting the control channel in other
subframes not indicated in the subframe bitmap.
[0113] In Example 17, the subject matter of any of Examples 15-16
can optionally wherein the control channel is time division
multiplexed (TDM) with the downlink shared channel.
[0114] In Example 18, the subject matter of Example 17 can
optionally include wherein the control channel is further frequency
division multiplexed (FDM) with the downlink shared channel.
[0115] Example 19 includes an apparatus for an Evolved Node-B
(eNB), the apparatus comprising hardware processing circuitry and
transceiver circuitry, the hardware processing circuitry to
configure the transceiver circuitry to transmit, to a first user
equipment (UE), a control channel occupying an initial number of
orthogonal frequency division multiplexing (OFDM) symbols of a
downlink subframe, wherein the control channel occupies less than N
physical resource blocks (PRBs) of a system bandwidth comprised of
N PRBs; transmit a downlink shared channel to the first UE, wherein
the downlink shared channel is time division multiplexed (TDM) with
the control channel; and transmit the control channel to a second
UE.
[0116] In Example 20, the subject matter of Example 19 can
optionally include wherein the transceiver circuitry is further
configured to transmit the control channel to the first UE and to
the second UE on the same OFDM symbol using a full system bandwidth
and different beamforming weights.
[0117] In Example 21, the subject matter of any of Examples 19-20
can optionally include wherein the transceiver circuitry is further
configured to transmit the control channel to the first UE and to
the second UE on the same OFDM symbol and with same beamforming
weight in a frequency-division multiplexing (FDM) fashion using
different resource elements (REs).
[0118] In Example 22, the subject matter of any of Examples 19-21
can optionally include wherein the hardware processing circuitry is
further to configure the transceiver circuitry to transmit a value
for the initial number of OFDM symbols in one of a mater
information block (MIB), a system information block (SIB),
UE-specific radio resource control (RRC) signaling, and a Physical
Control Format Indicator Channel (PCFICH).
[0119] In Example 23, the subject matter of any of Examples 19-22
can optionally include wherein the control channel occupies all
OFDM symbols of a downlink slot at a frequency or set of
frequencies; and the downlink shared channel is FDM with the
control channel.
[0120] In Example 24, the subject matter of any of Examples 19-23
can optionally include wherein the control channel occupies N
physical resource blocks (PRBs) of a system bandwidth comprised of
N PRBs.
[0121] The drawings and the forgoing description gave examples of
the present disclosure. Although depicted as a number of disparate
functional items, those skilled in the art will appreciate that one
or more of such elements can well be combined into single
functional elements. Alternatively, certain elements can be split
into multiple functional elements. Elements from one embodiment can
be added to another embodiment. For example, orders of processes
described herein can be changed and are not limited to the manner
described herein. Moreover, the actions of any flow diagram need
not be implemented in the order shown; nor do all of the acts
necessarily need to be performed. Also, those acts that are not
dependent on other acts can be performed in parallel with the other
acts. The scope of the present disclosure, however, is by no means
limited by these specific examples. Numerous variations, whether
explicitly given in the specification or not, such as differences
in structure, dimension, and use of material, are possible. The
scope of the disclosure is at least as broad as given by the
following claims.
* * * * *