U.S. patent application number 17/751403 was filed with the patent office on 2022-09-08 for uplink channel dynamic waveform switching.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Tingfang Ji, Jing Jiang, Renqiu Wang, Hao Xu, Wei Zeng.
Application Number | 20220287032 17/751403 |
Document ID | / |
Family ID | 1000006348528 |
Filed Date | 2022-09-08 |
United States Patent
Application |
20220287032 |
Kind Code |
A1 |
Wang; Renqiu ; et
al. |
September 8, 2022 |
UPLINK CHANNEL DYNAMIC WAVEFORM SWITCHING
Abstract
Methods, systems, and devices for wireless communication are
described. A user equipment (UE) and a base station may support
switching from one waveform to another on uplink channels. For
example, a UE and a base station may utilize both frequency
division multiplexing (SC-FDM) waveform and an orthogonal frequency
division multiplexing (OFDM) waveforms based on channel conditions
and other factors. In some examples, a UE may switch for some
uplink channels, and use a single waveform for other channels. For
example, switching waveforms for channels that utilize frequency
domain code division multiplexing (CDM) channel may interrupt the
orthogonality of multiplexed transmissions. A UE may transition
from one waveform to another either autonomously or based on an
explicit indication from a base station. If a UE switches
autonomously, it may send an indication of the transition to the
serving base station.
Inventors: |
Wang; Renqiu; (San Diego,
CA) ; Xu; Hao; (Beijing, CN) ; Zeng; Wei;
(San Diego, CA) ; Jiang; Jing; (San Diego, CA)
; Ji; Tingfang; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000006348528 |
Appl. No.: |
17/751403 |
Filed: |
May 23, 2022 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15458017 |
Mar 13, 2017 |
11363572 |
|
|
17751403 |
|
|
|
|
62369719 |
Aug 1, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/0092 20130101;
H04L 5/0021 20130101; H04L 5/0007 20130101; H04W 72/0413 20130101;
H04L 5/0048 20130101; H04B 17/336 20150115; H04L 1/0009 20130101;
H04B 7/0413 20130101; H04L 5/0051 20130101; H04L 1/0003 20130101;
H04L 27/0008 20130101; H04L 5/0028 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04B 17/336 20060101
H04B017/336; H04B 7/0413 20060101 H04B007/0413; H04L 1/00 20060101
H04L001/00 |
Claims
1. An apparatus for wireless communications, comprising: a
processor; memory coupled with the processor; and instructions
stored in the memory and operable, when executed by the processor,
to cause the apparatus to: determine whether an uplink physical
layer channel is configured for frequency domain code division
multiplexing (CDM); select a waveform switching mode based at least
in part on the determination of whether the uplink physical layer
channel is configured for frequency domain CDM; identify a waveform
for the uplink physical layer channel based at least in part on the
waveform switching mode; and communicate on the uplink physical
layer channel using the identified waveform.
2. The apparatus of claim 1, wherein the waveform switching mode
comprises a switching mode based at least in part on the
determining, and the instructions are further operable, when
executed by the processor, to cause the apparatus to: switch the
waveform for the uplink physical layer channel based at least in
part on the switching mode.
3. The apparatus of claim 1, wherein the instructions are further
operable, when executed by the processor, to cause the apparatus
to: determine that the uplink physical layer channel is configured
for frequency domain CDM, wherein the waveform switching mode
comprises a non-switching mode; and maintain the identified
waveform for the uplink physical layer channel based at least in
part on the non-switching mode.
4. The apparatus of claim 1, wherein the uplink physical layer
channel comprises a physical uplink shared channel (PUSCH).
5. The apparatus of claim 1, wherein the waveform switching mode
comprises one or more rules for selecting an orthogonal frequency
division multiplexing (OFDM) waveform or a single carrier frequency
division multiplexing (SC-FDM) waveform.
6. A method for wireless communications, comprising: determining
whether an uplink physical layer channel is configured for
frequency domain code division multiplexing (CDM); selecting a
waveform switching mode based at least in part on the determination
of whether the uplink physical layer channel is configured for
frequency domain CDM; identifying a waveform for the uplink
physical layer channel based at least in part on the waveform
switching mode; and communicating on the uplink physical layer
channel using the identified waveform.
7. The method of claim 6, wherein the waveform switching mode
comprises a switching mode based at least in part on the
determining, the method further comprising: switching the waveform
for the uplink physical layer channel based at least in part on the
switching mode.
8. The method of claim 6, further comprising: determining that the
uplink physical layer channel is configured for frequency domain
CDM, wherein the waveform switching mode comprises a non-switching
mode; and maintaining the identified waveform for the uplink
physical layer channel based at least in part on the non-switching
mode.
9. The method of claim 6, wherein the uplink physical layer channel
comprises a physical uplink shared channel (PUSCH).
10. The method of claim 6, wherein the waveform switching mode
comprises one or more rules for selecting an orthogonal frequency
division multiplexing (OFDM) waveform or a single carrier frequency
division multiplexing (SC-FDM) waveform.
11. An apparatus for wireless communications, comprising: means for
determining whether an uplink physical layer channel is configured
for frequency domain code division multiplexing (CDM); means for
selecting a waveform switching mode based at least in part on the
determination of whether the uplink physical layer channel is
configured for frequency domain CDM; means for identifying a
waveform for the uplink physical layer channel based at least in
part on the waveform switching mode; and means for communicating on
the uplink physical layer channel using the identified
waveform.
12. The apparatus of claim 11, wherein the waveform switching mode
comprises a switching mode based at least in part on the
determining, the apparatus further comprising: means for switching
the waveform for the uplink physical layer channel based at least
in part on the switching mode.
13. The apparatus of claim 11, further comprising: means for
determining that the uplink physical layer channel is configured
for frequency domain CDM, wherein the waveform switching mode
comprises a non-switching mode; and means for maintaining the
identified waveform for the uplink physical layer channel based at
least in part on the non-switching mode.
14. The apparatus of claim 11, wherein the uplink physical layer
channel comprises a physical uplink shared channel (PUSCH).
15. The apparatus of claim 11, wherein the waveform switching mode
comprises one or more rules for selecting an orthogonal frequency
division multiplexing (OFDM) waveform or a single carrier frequency
division multiplexing (SC-FDM) waveform.
16. A non-transitory computer-readable medium storing code for
wireless communications, the code comprising instructions
executable by a processor to: determine whether an uplink physical
layer channel is configured for frequency domain code division
multiplexing (CDM); select a waveform switching mode based at least
in part on the determination of whether the uplink physical layer
channel is configured for frequency domain CDM; identify a waveform
for the uplink physical layer channel based at least in part on the
waveform switching mode; and communicate on the uplink physical
layer channel using the identified waveform.
17. The non-transitory computer-readable medium of claim 16,
wherein the waveform switching mode comprises a switching mode
based at least in part on the determining, and the instructions are
further executable by the processor to: switch the waveform for the
uplink physical layer channel based at least in part on the
switching mode.
18. The non-transitory computer-readable medium of claim 16,
wherein the instructions are further executable by the processor
to: determine that the uplink physical layer channel is configured
for frequency domain CDM, wherein the waveform switching mode
comprises a non-switching mode; and maintain the identified
waveform for the uplink physical layer channel based at least in
part on the non-switching mode.
19. The non-transitory computer-readable medium of claim 16,
wherein the uplink physical layer channel comprises a physical
uplink shared channel (PUSCH).
20. The non-transitory computer-readable medium of claim 16,
wherein the waveform switching mode comprises one or more rules for
selecting an orthogonal frequency division multiplexing (OFDM)
waveform or a single carrier frequency division multiplexing
(SC-FDM) waveform.
Description
CROSS REFERENCES
[0001] The present application for patent is a Divisional of U.S.
patent application Ser. No. 15/458,017 by WANG et al., entitled
"UPLINK CHANNEL DYNAMIC WAVEFORM SWITCHING" filed Mar. 13, 2017,
which claims priority to U.S. Provisional Patent Application No.
62/369,719 by WANG et al., entitled "UPLINK CHANNEL DYNAMIC
WAVEFORM SWITCHING," filed Aug. 1, 2016, each of which is assigned
to the assignee hereof, and each of which is hereby expressly
incorporated by reference herein in its entirety.
INTRODUCTION
[0002] The following relates generally to wireless communication,
and more specifically to uplink (UL) channel dynamic waveform
switching.
[0003] Wireless communications systems are widely deployed to
provide various types of communication content such as voice,
video, packet data, messaging, broadcast, and so on. These systems
may be capable of supporting communication with multiple users by
sharing the available system resources (e.g., time, frequency, and
power). Examples of such multiple-access systems include code
division multiple access (CDMA) systems, time division multiple
access (TDMA) systems, frequency division multiple access (FDMA)
systems, and orthogonal frequency division multiple access (OFDMA)
systems, (e.g., a Long Term Evolution (LTE) system). A wireless
multiple-access communications system may include a number of base
stations, each simultaneously supporting communication for multiple
communication devices, which may be otherwise known as user
equipment (UE).
[0004] UEs and base stations may communicate using one of a variety
of multiplexing schemes. For example, in some systems, a UE and a
base station may communicate single carrier frequency division
multiplexing (SC-FDM) on uplink channels and use orthogonal
frequency division multiplexing (OFDM) on downlink channels.
However, in some cases, OFDM may provide improved performance than
SC-FDM for uplink transmissions. Thus, using SC-FDM exclusively may
result in suboptimal performance, and reduced throughput.
SUMMARY
[0005] A method of wireless communication is described. The method
may include determining whether an uplink physical layer channel is
configured for frequency domain code division multiplexing (CDM),
selecting a waveform switching mode based at least in part on the
determination of whether the physical layer channel is configured
for frequency domain CDM, identifying a waveform for the uplink
physical layer channel based at least in part on the waveform
switching mode, and communicating on the uplink physical layer
channel using the identified waveform.
[0006] An apparatus for wireless communication is described. The
apparatus may include means for determining whether an uplink
physical layer channel is configured for frequency domain CDM,
means for selecting a waveform switching mode based at least in
part on the determination of whether the uplink physical layer
channel is configured for frequency domain CDM, means for
identifying a waveform for the uplink physical layer channel based
at least in part on the waveform switching mode, and means for
communicating on the uplink physical layer channel using the
identified waveform.
[0007] Another apparatus for wireless communication is described.
The apparatus may include a processor, memory in electronic
communication with the processor, and instructions stored in the
memory. The instructions may be operable to cause the processor to
determine whether an uplink physical layer channel is configured
for frequency domain CDM, select a waveform switching mode based at
least in part on the determination of whether the uplink physical
layer channel is configured for frequency domain CDM, identify a
waveform for the uplink physical layer channel based at least in
part on the waveform switching mode, and communicate on the uplink
physical layer channel using the identified waveform.
[0008] A non-transitory computer readable medium for wireless
communication is described. The non-transitory computer-readable
medium may include instructions operable to cause a processor to
determine whether an uplink physical layer channel is configured
for frequency domain CDM, select a waveform switching mode based at
least in part on the determination of whether the uplink physical
layer channel is configured for frequency domain CDM, identify a
waveform for the uplink physical layer channel based at least in
part on the waveform switching mode, and communicate on the uplink
physical layer channel using the identified waveform.
[0009] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for determining that
the uplink physical layer channel may be not configured for
frequency domain CDM, where the waveform switching mode includes a
switching mode. Some examples of the method, apparatus, and
non-transitory computer-readable medium described above may further
include processes, features, means, or instructions for switching
the waveform for the uplink physical layer channel based at least
in part on the switching mode.
[0010] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for determining that
the uplink physical layer channel may be configured for frequency
domain CDM, where the waveform switching mode includes a
non-switching mode. Some examples of the method, apparatus, and
non-transitory computer-readable medium described above may further
include processes, features, means, or instructions for maintaining
the identified waveform for the uplink physical layer channel based
at least in part on the non-switching mode.
[0011] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the uplink
physical layer channel includes a physical uplink shared channel
(PUSCH). In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the
waveform switching mode includes one or more rules for selecting an
OFDM waveform or an SC-FDM waveform.
[0012] A method of wireless communication is described. The method
may include communicating on an uplink physical layer channel using
a first waveform, selecting a second waveform based at least in
part on one or more waveform switching parameters, and
communicating on the uplink physical layer channel using the second
waveform.
[0013] An apparatus for wireless communication is described. The
apparatus may include means for communicating on an uplink physical
layer channel using a first waveform, means for selecting a second
waveform based at least in part on one or more waveform switching
parameters, and means for communicating on the uplink physical
layer channel using the second waveform.
[0014] Another apparatus for wireless communication is described.
The apparatus may include a processor, memory in electronic
communication with the processor, and instructions stored in the
memory. The instructions may be operable to cause the processor to
communicate on an uplink physical layer channel using a first
waveform, select a second waveform based at least in part on one or
more waveform switching parameters, and communicate on the uplink
physical layer channel using the second waveform.
[0015] A non-transitory computer readable medium for wireless
communication is described. The non-transitory computer-readable
medium may include instructions operable to cause a processor to
communicate on an uplink physical layer channel using a first
waveform, select a second waveform based at least in part on one or
more waveform switching parameters, and communicate on the uplink
physical layer channel using the second waveform.
[0016] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for identifying a
change in a multiple-input multiple output (MIMO) configuration,
where the one or more waveform switching parameters include a
parameter based on the MIMO configuration. Some examples of a
change in a MIMO configuration may include a change from a MIMO
configuration to a single-input multiple output (SIMO)
configuration.
[0017] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for identifying a
change in a SIMO configuration, wherein the one or more waveform
switching parameters comprise a parameter based on the SIMO
configuration. Some examples of a change in a SIMO configuration
may include a change from a SIMO configuration to a MIMO
configuration.
[0018] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for identifying a
number of channels in a transmission time interval (TTI) of the
uplink physical layer channel, where the one or more waveform
switching parameters include a parameter based on the number of
channels in the TTI.
[0019] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the uplink
physical layer channel comprises a PUSCH, and where identifying the
number of channels in the TTI comprises: determining that a
physical uplink control channel (PUCCH) transmission or a SRS
transmission may be scheduled during the TTI. Some examples of the
method, apparatus, and non-transitory computer-readable medium
described above may further include processes, features, means, or
instructions for identifying a change in a Doppler shift of a UE,
where the one or more waveform switching parameters comprise a
parameter based on the Doppler shift of the UE.
[0020] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above,
communicating on the uplink physical layer channel using the second
waveform comprises: communicating using a multi-cluster
transmission pattern based at least in part on the change in the
Doppler shift. Some examples of the method, apparatus, and
non-transitory computer-readable medium described above may further
include processes, features, means, or instructions for identifying
a change in a link budget of a UE, where one or more waveform
switching parameters comprise a parameter based on the link budget
of the UE.
[0021] In some examples of the method, apparatus, and
non-transitory computer readable medium described above,
communicating on the uplink physical layer channel using the second
waveform comprises: identifying a change in SNR of a user
equipment, wherein the one or more waveform switching parameters
comprise a parameter based on the SNR of the UE. Some examples of
the method, apparatus, and non-transitory computer-readable medium
described above may further include processes, features, means, or
instructions for identifying a change in an modulation coding
scheme (MCS) of a user equipment (UE), wherein the one or more
waveform switching parameters comprise a parameter based on the MCS
of the UE.
[0022] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the one or
more waveform switching parameters comprise at least two of a MIMO
configuration, a single-input multiple output (SIMO) configuration,
a number of channels, a Doppler shift, and a link budget, a signal
to noise ratio (SNR), and a MCS. In some examples of the method,
apparatus, and non-transitory computer-readable medium described
above, the second waveform may be applied to data transmissions,
reference signal transmissions, or both.
[0023] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above,
communicating on the uplink physical layer channel using the first
waveform comprises: transmitting a PUSCH during a first symbol of a
TTI. In some examples of the method, apparatus, and non-transitory
computer-readable medium described above, communicating on the
uplink physical layer channel using the second waveform comprises:
transmitting the PUSCH during a second symbol of the TTI. Some
examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for transmitting a SRS
during the second symbol of the TTI, where the second symbol of the
TTI comprises a last symbol of the TTI.
[0024] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for transmitting an
indication of the second waveform to a UE. Some examples of the
method, apparatus, and non-transitory computer-readable medium
described above may further include processes, features, means, or
instructions for receiving an indication of the second waveform
from a base station, where the second waveform may be selected
based at least in part on the indication.
[0025] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for transmitting an
indication of the second waveform to a base station. Some examples
of the method, apparatus, and non-transitory computer-readable
medium described above may further include processes, features,
means, or instructions for receiving an indication of the second
waveform from a UE, where the second waveform may be selected based
at least in part on the indication.
[0026] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the second
waveform may be autonomously selected by a UE based at least in
part on one or more waveform switching parameters. In some examples
of the method, apparatus, and non-transitory computer-readable
medium described above, the second waveform may be identified by a
base station independently of the UE.
[0027] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the first
waveform comprises an OFDM waveform and the second waveform
comprises an SC-FDM waveform. In some examples of the method,
apparatus, and non-transitory computer-readable medium described
above, the first waveform comprises an SC-FDM waveform and the
second waveform comprises an OFDM.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIGS. 1 and 2 illustrate examples of a system for wireless
communication that supports UL channel dynamic waveform switching
in accordance with one or more aspects of the present
disclosure.
[0029] FIGS. 3A and 3B illustrate example channel structures that
support uplink channel multiplexing and waveform selection in
accordance with one or more aspects of the present disclosure.
[0030] FIGS. 4A and 4B illustrate example channel structures that
support uplink channel multiplexing and waveform selection in
accordance with one or more aspects of the present disclosure.
[0031] FIG. 5 illustrates an example of a waveform switch that
supports UL channel dynamic waveform switching in accordance with
one or more aspects of the present disclosure.
[0032] FIG. 6 illustrates an example of a waveform switch in a TTI
that supports UL channel dynamic waveform switching in accordance
with one or more aspects of the present disclosure.
[0033] FIGS. 7 and 8 show examples of process flow diagrams that
support UL channel dynamic waveform switching in accordance with
one or more aspects of the present disclosure.
[0034] FIGS. 9 through 11 show block diagrams of a device that
supports UL channel dynamic waveform switching in accordance with
one or more aspects of the present disclosure.
[0035] FIG. 12 illustrates a block diagram of a system including a
UE that supports UL channel dynamic waveform switching in
accordance with one or more aspects of the present disclosure.
[0036] FIG. 13 illustrates a block diagram of a system including a
base station that supports UL channel dynamic waveform switching in
accordance with one or more aspects of the present disclosure.
[0037] FIGS. 14 through 21 illustrate methods for UL channel
dynamic waveform switching in accordance with one or more aspects
of the present disclosure.
DETAILED DESCRIPTION
[0038] A wireless communications system may support uplink
communication using multiple multiplexing waveforms including
SC-FDM waveforms and OFDM waveforms. SC-FDM waveforms may have a
lower peak to average power ratio (PAPR), which may be preferred
when a device is power limited or link budget limited. Using an
SC-FDM waveform may also be appropriate for transmissions using a
multi-cluster transmission pattern. However, UEs with a high
signal-to-noise ratio (SNR) may prefer to use an OFDM waveform to
improve performance. Using an OFDM waveform may also enable support
for different reference signal to data ratios.
[0039] Thus, UEs and base stations may utilize both waveforms to
take advantage of the distinct properties of each waveform type
under different circumstances. In some examples, different
waveforms may be used for different uplink channels. For example,
data channels may use a different waveform than reference signals.
In other examples, data and reference signals may be transmitted
using the same waveform, but devices may switch between using
SC-FDM and OFDM waveforms. In some cases, whether devices switch
waveforms may depend on whether switching will affect the
orthogonality of multiplexed transmissions. For example, a UE and a
base station may choose not to switch waveforms if an uplink
channel uses frequency domain code division multiplexing (CDM). In
some examples, dynamic switching may occur within a transmission
time interval (TTI).
[0040] Waveform selection may be based on one or more transmission
conditions. For example, a waveform may be selected based on a
multiple-input multiple output (MIMO) mode, a number of channels, a
link budget, a SNR, or a modulation and coding scheme (MCS),
Doppler information, or a combination thereof.
[0041] In some examples, physical uplink control channel (PUCCH)
and sounding reference signal (SRS) transmissions may use an SC-FDM
waveform, while PUSCH transmissions may use a dynamically selected
waveform.
[0042] In some examples, physical uplink control channel (PUCCH)
and sounding reference signal (SRS) transmissions may use an OFDM
waveform, while PUSCH transmissions may use a dynamically selected
waveform.
[0043] Aspects of the disclosure are initially described in the
context of a wireless communications system. Examples of channel
configurations that support dynamic waveform switching are then
described. Further examples illustrate procedures for either UE
initiated or base station directed waveform switching. Aspects of
the disclosure are further illustrated by and described with
reference to apparatus diagrams, system diagrams, and flowcharts
that relate to UL channel dynamic waveform switching.
[0044] FIG. 1 illustrates an example of a wireless communications
system 100 in accordance with various aspects of the present
disclosure. The wireless communications system 100 includes base
stations 105 (e.g., gNodeBs (gNBs), network access devices, access
node controllers (ANCs) and/or radio heads (RHs)), UEs 115, and a
core network 130. In some examples, the wireless communications
system 100 may be an LTE (or LTE-Advanced) network. In some
examples, wireless communications system 100 may support dynamic
waveform switching for uplink channels.
[0045] Base stations 105 may wirelessly communicate with UEs 115
via one or more base station antennas. Each base station 105 may
provide communication coverage for a respective geographic coverage
area 110. Communication links 125 shown in wireless communications
system 100 may include UL transmissions from a UE 115 to a base
station 105, or downlink (DL) transmissions, from a base station
105 to a UE 115. A UE 115 may communicate with the core network 130
through communication link 135. UEs 115 may be dispersed throughout
the wireless communications system 100, and each UE 115 may be
stationary or mobile.
[0046] The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. At least some of the
base stations 105 (e.g., network access devices, gNBs, ANCs, RHs)
may interface with the core network 130 through backhaul links 132
(e.g., S1, S2, etc.) with the core network 130 and may perform
radio configuration and scheduling for communication with the UEs
115. In various examples, ANCs may communicate, either directly or
indirectly (e.g., through core network 130), with each other over
backhaul links 134 (e.g., X1, X2, etc.), which may be wired or
wireless communication links. Each ANC may additionally or
alternatively communicate with a number of UEs 115 through a number
of smart radio heads. In an alternative configuration of the
wireless communications system 100, the functionality of an ANC may
be provided by a radio head or distributed across the radio heads
of a gNB.
[0047] In some examples, the wireless communications system 100 may
include a 5G network. In other examples, the wireless
communications system 100 may include a LTE/LTE-A network. The
wireless communications system 100 may in some cases be a
heterogeneous network, in which different types of base stations
105 (e.g., gNBs, eNBs, ANCs, etc.) provide coverage for various
geographical regions. The term "cell" is a 3GPP term that can be
used to describe a base station, a radio head, a carrier or
component carrier associated with a base station or a radio head,
or a coverage area (e.g., sector, etc.) of a carrier or base
station, depending on context.
[0048] Base stations 105 may wirelessly communicate with UEs 115
via one or more base station antennas. Each base station 105 may
provide communication coverage for a respective geographic coverage
area 110. Communication links 125 shown in wireless communications
system 100 may include uplink transmissions from a UE 115 to a base
station 105, or downlink transmissions, from a base station 105 to
a UE 115. A UE 115 may communicate with the core network 130
through communication link 135. UEs 115 may be dispersed throughout
the wireless communications system 100, and each UE 115 may be
stationary or mobile.
[0049] A UE 115 may also additionally or alternatively be referred
to as a mobile station, a subscriber station, a mobile unit, a
subscriber unit, a wireless unit, a remote unit, a mobile device, a
wireless device, a wireless communications device, a remote device,
a mobile subscriber station, an access terminal, a mobile terminal,
a wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology. A UE
115 may additionally or alternatively be a cellular phone, a
personal digital assistant (PDA), a wireless modem, a wireless
communication device, a handheld device, a tablet computer, a
laptop computer, a cordless phone, a personal electronic device, a
handheld device, a personal computer, a wireless local loop (WLL)
station, an Internet of things (IoT) device, an Internet of
Everything (IoE) device, a machine type communication (MTC) device,
an appliance, an automobile, or the like.
[0050] Base stations 105 may communicate with the core network 130
and with one another. For example, base stations 105 may interface
with the core network 130 through backhaul links 132 (e.g., S1,
etc.). Base stations 105 may communicate with one another over
backhaul links 134 (e.g., X2, etc.) either directly or indirectly
(e.g., through core network 130). Base stations 105 may perform
radio configuration and scheduling for communication with UEs 115,
or may operate under the control of a base station controller (not
shown). In some examples, base stations 105 may be macro cells,
small cells, hot spots, or the like. Base stations 105 may also be
referred to as eNodeBs (eNBs) 105.
[0051] A base station 105 may include base station waveform
switching manager 101 and a UE 115 may include a UE waveform
switching manager 102. Base station waveform switching manager 101
and UE waveform switching manager 102 may be examples of aspects of
the waveform switching manager described with reference to FIGS.
9-13. Base station waveform switching manager 101 and UE waveform
switching manager 102 may determine whether an uplink physical
layer channel is configured for frequency domain CDM, select a
waveform switching mode based on the determination of whether the
physical layer channel is configured for frequency domain CDM, and
identify a waveform for the physical layer channel based on the
waveform switching mode. Base station waveform switching manager
101 and UE waveform switching manager 102 may also select a second
waveform based on one or more waveform switching parameters.
[0052] In wireless communications system 100, a UE 115 may
communicate with a base station using subframes spanning a given
time interval (e.g., 1 ms). The UE 115 may receive packets from a
base station 105 over a downlink subframe and transmit packets to a
base station 105 over an uplink subframe. A downlink subframe may
span an available bandwidth and have symbols allocated for a
physical downlink control channel (PDCCH), a physical downlink
shared channel (PDSCH), a guard period (GP), and a common burst. An
uplink subframe may span the available bandwidth and have symbols
allocated for a PDCCH, an uplink burst, a GP, and a common burst.
The uplink common burst and uplink burst may include a sounding
reference signal (SRS), a physical uplink control channel (PUCCH,
or a physical uplink control channel (PUSCH) and the GP may be used
when switching from downlink to uplink during a subframe.
[0053] A base station 105 and a UE 115 may utilize different
waveforms based on different multiplexing schemes. For example,
OFDM employs multiple overlapping radio frequency carriers, each
operating at a chosen frequency that is orthogonal to the other
frequencies to produce a transmission scheme that supports higher
bit rates due to parallel channel operation. OFDMA is a multiple
access scheme relying on the use of OFDM, where individual
subcarriers (or groups of subcarriers) are assigned to distinct
users.
[0054] SC-FDM uses an additional Fourier transform processing
operation (as compared to OFDM) to combine multiple subcarriers
into a single SC-FDM symbol. Thus, unlike OFDM, in SC-FDM the
signal modulated onto a given subcarrier is a linear combination
(typically via a discrete Fourier transform (DFT) precoding
operation) of multiple data symbols. In some cases, all the
transmitted subcarriers of an SC-FDMA signal carry a component of
each modulated data symbol. This gives SC-FDMA its single-carrier
property, which results in the lower Cubic Metric (CM) and Peak to
Average Power Ratio (PAPR). In some cases, a UE 115 or a base
station 105 may switch between using OFDM and SC-FDM waveforms to
take advantage of the properties of both techniques.
[0055] Other multiplexing schemes may also be used in addition, or
as an alternative, to OFDM and SC-FDM. For example, CDM may be
based on applying different orthogonal cover codes to multiplexed
transmissions. An orthogonal cover code may be applied either in
the frequency domain or in the time domain.
[0056] A PUCCH may be used for uplink acknowledgements (ACKs),
scheduling requests (SRs) and channel quality information (CQI) and
other uplink control information. A PUCCH may be mapped to a
control channel defined by a code and two consecutive resource
blocks. Uplink control signaling may depend on the presence of
timing synchronization for a cell. PUCCH resources for SR and CQI
reporting may be assigned (and revoked) through radio resource
control (RRC) signaling. In some cases, resources for SR may be
assigned after acquiring synchronization through a random access
channel (RACH) procedure. In other cases, an SR may not be assigned
to a UE 115 through the RACH (i.e., synchronized UEs may or may not
have a dedicated SR channel). PUCCH resources for SR and CQI may be
lost when the UE is no longer synchronized. A PUSCH may be the LTE
uplink physical channel carrying scheduled data traffic, and
control signaling if some is required to be transmitted in the same
subframe.
[0057] In some cases, a UE may transmit an uplink channel such as a
PUSCH, a PUCCH, an SRS, or an ultra-reliable low-latency
communications channel (URLCC) to a base station 105 over a single
uplink subframe. In other examples, multiple UEs may be capable of
transmitting different uplink channels over the same uplink
subframe. Different channels may be transmitted according to
different waveforms (e.g., an SC-FDM waveform, an OFDM waveform, or
the like). Different channels may be multiplexed with different
multiplexing techniques such as frequency division multiplexing
(FDM), time division multiplexing (TDM), CDM, or spatial division
multiplexing (SDM), among other types of multiplexing.
[0058] A UE 115 may be configured to collaboratively communicate
with multiple base stations 105 through, for example, Multiple
Input Multiple Output (MIMO), Coordinated Multi-Point (COMP), or
other schemes. MIMO techniques use multiple antennas on the base
stations or multiple antennas on the UE to take advantage of
multipath environments to transmit multiple data streams. COMP
includes techniques for dynamic coordination of transmission and
reception by a number of eNBs to improve overall transmission
quality for UEs as well as increasing network and spectrum
utilization. Some MIMO configurations (i.e., multi-user (MU) MIMO)
may be used to multiplex different UEs 115. Oher configurations
(i.e., single user (SU) MIMO) may be based on communication with a
single UE 115.
[0059] Data communicated between a UE 115 and a base station 105
may be divided into logical channels, transport channels, and
physical layer channels. Channels may also be classified into
Control Channels and Traffic Channels. Logical control channels may
include paging control channel (PCCH) for paging information,
broadcast control channel (BCCH) for broadcast system control
information, multicast control channel (MCCH) for transmitting
multimedia broadcast multicast services (MBMS) scheduling and
control information, dedicated control channel (DCCH) for
transmitting dedicated control information, common control channel
(CCCH) for random access information, dedicated traffic channel
(DTCH) for dedicated UE data, and machine type communication (MTC),
for multicast data. DL transport channels may include broadcast
channel (BCH) for broadcast information, a downlink shared channel
(DL-SCH) for data transfer, paging channel (PCH) for paging
information, and multicast channel (MCH) for multicast
transmissions. UL transport channels may include RACH for access
and UL-SCH for data.
[0060] DL physical channels may include physical broadcast channel
(PBCH) for broadcast information, physical control format indicator
channel (PCFICH) for control format information, physical downlink
control channel (PDCCH) for control and scheduling information,
physical hybrid ARQ indicator channel (PHICH) for hybrid automatic
repeat request (HARD) status messages, physical downlink shared
channel (PDSCH) for user data and physical multicast channel (PMCH)
for multicast data. UL physical channels may include PRACH for
access messages, physical uplink control channel (PUCCH) for
control data, and physical uplink shared channel (PUSCH) for user
data.
[0061] An SRS may be transmitted by UE 115 using a predetermined
sequence (e.g., a Zadoff-Chu sequence) so that a base station 105
may estimate the uplink channel quality. An SRS transmission may
not be associated with transmission of data on another channel, and
may be transmitted periodically on a wide bandwidth (e.g., a
bandwidth including more subcarriers than are allocated for uplink
data transmission). In some examples, multiple SRSs from the same
or different UEs may span varying bandwidths and number of symbols
in an uplink subframe.
[0062] An SRS may also be scheduled on multiple antenna ports and
may still be considered a single SRS transmission. An SRS
transmission may be categorized as a Type 0 (periodically
transmitted at equally spaced intervals) SRS or as a Type 1
(aperiodic) SRS. Thus, data gathered by a base station 105 from an
SRS may be used to inform an uplink scheduler. A base station 105
may also utilize an SRS to check timing alignment status and send
time alignment commands to the UE 115.
[0063] Wireless communications system 100 may operate in an
ultra-high frequency (UHF) frequency region using frequency bands
from 700 MHz to 2600 MHz (2.6 GHz), although in some cases wireless
local area network (WLAN) networks may use frequencies as high as 4
GHz. This region may also be known as the decimeter band, since the
wavelengths range from approximately one decimeter to one meter in
length. UHF waves may propagate mainly by line of sight, and may be
blocked by buildings and environmental features. However, the waves
may penetrate walls sufficiently to provide service to UEs 115
located indoors. Transmission of UHF waves is characterized by
smaller antennas and shorter range (e.g., less than 100 km)
compared to transmission using the smaller frequencies (and longer
waves) of the high frequency (HF) or very high frequency (VHF)
portion of the spectrum.
[0064] In some cases, wireless communications system 100 may also
utilize extremely high frequency (EHF) portions of the spectrum
(e.g., from 30 GHz to 300 GHz). This region may also be known as
the millimeter band, since the wavelengths range from approximately
one millimeter to one centimeter in length. Thus, EHF antennas may
be even smaller and more closely spaced than UHF antennas. In some
cases, this may facilitate use of antenna arrays within a UE 115
(e.g., for directional beamforming). However, EHF transmissions may
be subject to even greater atmospheric attenuation and shorter
range than UHF transmissions.
[0065] Thus, according to the present disclosure, a UE 115 and a
base station 105 may support switching from one waveform to another
on uplink channels. For example, a UE 115 and a base station 105
may utilize both frequency SC-FDM waveform and an OFDM waveforms
based on channel conditions and other factors. In some examples, a
UE 115 may switch for some uplink channels, and use a single
waveform for other channels. For example, switching waveforms for
channels that utilize frequency domain CDM channel may interrupt
the orthogonality of multiplexed transmissions. A UE 115 may
transition from one waveform to another either autonomously or
based on an explicit indication from a base station. If a UE 115
switches autonomously, it may send an indication of the transition
to the serving base station.
[0066] FIG. 2 illustrates an example of a wireless communications
system 200 for UL channel dynamic waveform switching in accordance
with one or more aspects of the present disclosure. Wireless
communications system 200 may include UE 115-a and base station
105-a, which may be examples of a UE 115 and a base station 105 of
FIG. 1. UE 115-a may switch waveforms of an uplink channel (e.g.,
PUSCH) while communicating with base station 105-a. For example, UE
115-a may switch from using an SC-FDM waveform to an OFDM waveform
or from an OFDM waveform to an SC-FDM waveform.
[0067] Base station 105-a may include base station waveform
switching manager 201 and UE 115-a may include a UE waveform
switching manager 202. Base station waveform switching manager 201
and UE waveform switching manager 202 may be examples of aspects of
the waveform switching manager described with reference to FIG. 1
and FIGS. 9-13. Base station waveform switching manager 201 and UE
waveform switching manager 202 may determine whether an uplink
physical layer channel is configured for frequency domain CDM,
select a waveform switching mode based on the determination of
whether the physical layer channel is configured for frequency
domain CDM, and identify a waveform for the physical layer channel
based on the waveform switching mode. Base station waveform
switching manager 201 and UE waveform switching manager 202 may
also select a second waveform based on one or more waveform
switching parameters.
[0068] Wireless communications system 200 may support uplink
communication using SC-FDM, OFDM, or both. SC-FDM waveforms may
have a lower peak to average power ratio (PAPR), which may be
preferred in some circumstances. For example, communicating using
an SC-FDM waveform may be more appropriate for link budget limited
UEs 115. Using an SC-FDM waveform may also be appropriate for
transmissions using a multi-cluster transmission pattern. However,
UEs 115 with a high signal-to-noise ratio (SNR) may prefer to use
an OFDM waveform. Using an OFDM waveform may also enable support
for different reference signal to data ratios. In some examples,
data and reference signals may be transmitted using the same
waveform, but the UEs 115 and base stations 105 may switch between
using SC-FDM and OFDM waveforms. In another example, data and
reference signals may be transmitted using different waveforms.
[0069] In some cases, UE 115-a and base station 105-a may decide
whether to switch waveforms based on how switching may affect the
orthogonality of transmissions. Specifically, UE 115-a and base
station 105-a may choose not to switch wave forms depending on if
an uplink channel uses frequency domain CDM. However, if a channel
CDM in the time domain (e.g., a Walsh cover), UE 115-a may switch
waveforms without interfering with the orthogonality of the CDM.
That is, UE 115-a and base station 105-a may dynamically switch
waveforms if time domain spreading is maintained.
[0070] In some examples, dynamic switching may occur within a TTI,
such as during a regular burst of PUSCH. For example, different
symbols in the regular burst may use different waveforms. Some
symbols of the PUSCH regular burst may use OFDM, and some symbols
of the PUSCH regular burst may use SC-FDM. In some cases, switching
waveforms in PUSCH may not affect a waveform of a PUCCH or a
waveform of an SRS if they are CDMed in frequency domain.
[0071] Selecting the waveform type may be based on one or more
transmission conditions. For example, SC-FDM or OFDM waveform
selection may be based on a MIMO mode, a number of channels, a link
budget, a SNR, or a modulation and coding scheme (MCS), Doppler
information, or a combination thereof. In some of these examples,
PUCCH and SRS transmissions may use an SC-FDM waveform and a
localized transmission pattern. The waveform for reference signals
and data symbols may be independent of each other, and the waveform
switching may also be independent. For example, a waveform for data
symbols may switch, but a waveform for reference signal symbols may
stay the same.
[0072] In a first example, waveform switching may be based on a
MIMO mode in PUSCH. For example, if UE 115-a and base station 105-a
are configured for single-input, multiple-output (SIMO) mode
communication, UE 115-a may transmit an SC-FDM waveform, or UE
115-a may transmit data using an SC-FDM waveform and reference
signals with an OFDM waveform. If UE 115-a and base station 105-a
are communicating using a multi-user (MU) MIMO (MU-MIMO)
configuration, UE 115-a and base station 105-a may communicate on
PUSCH using an SC-FDM or a OFDM waveform. If UE 115-a and base
station 105-a are communicating using a single user (SU) MIMO
(SU-MIMO) configuration, UE 115-a and base station 105-a may
communicate on PUSCH using an SC-FDM or OFDM waveform. Each MIMO
mode may use a different waveform, so the waveform may switch if
the MIMO mode changes. In some examples, a change in MIMO mode may
include a change from a SIMO configuration to a MIMO configuration,
or a change from a MIMO configuration to a SIMO configuration. A
change in MIMO mode may also include a change from a MU-MIMO
configuration to a SU-MIMO configuration, or a change from a
SU-MIMO configuration to a MU-MIMO configuration, or any
combination of changes from one of the above mentioned
configurations a different one of the above mentioned
configurations.
[0073] In another example, waveform switching may be based on a
number of channels UE 115-a and base station use to communicate. If
UE 115-a and base station 105-a are communicating only on PUSCH, UE
115-a and base station 105-a may communicate on PUSCH using and an
SC-FDM waveform. However, switching may occur when PUSCH is
transmitted with another channel. In some examples, in a MU-MIMO
configuration, UE 115-a and base station 105-a may communicate on
PUSCH using an SC-FDM waveform. In a SIMO or SU-MIMO configuration,
UE 115-a and base station 105-a may communicate on PUSCH using an
OFDM waveform. PUCCH and SRS waveforms may continue to be SC-FDM or
OFDM while the waveform for PUSCH communication switches.
[0074] Waveform switching may also be based on a link budget or an
MCS. If UE 115-a is link budget limited, or has a low SNR, or has a
low MCS, UE 115-a and base station 105-a may communicate on an
uplink channel using an SC-FDM waveform. If UE 115-a is high SNR,
UE 115-a may transmit data using an OFDM waveform and transmit
reference signals with an SC-FDM waveform or an OFDM waveform.
Switching may occur when the link budget of UE 115-a changes. For
example, if UE 115-a moves toward base station 105-a, UE 115-a and
base station 105-a may switch from an OFDM waveform to an SC-FDM
waveform. For link budget and MCS based switching, PUCCH and SRS
may use a SC-FDM waveform.
[0075] In another example, waveform switching may be based on a
Doppler shift. For example, if UE 115-a has a low Doppler shift, UE
115-a may use an SC-FDM waveform for PUSCH. High Doppler shift UEs
115 may use a multi-cluster transmission pattern. High Doppler
shift UEs 115 may transmit data using an OFDM or SC-FDM waveform
and transmit reference signals with an OFDM waveform. In some
cases, SRS may not be frequent enough for base station 105-a to
choose a preferred band. Multi-cluster transmission patterns may
provide frequency diversity and be more robust against insufficient
SRS. Transmitting reference signals using an OFDM waveform may
allow for more reference signal symbols to track channel variation
while balancing a reference signal to data ratio. Switching may
occur when a Doppler shift of UE 115-a changes.
[0076] Waveform switching may also be based on a combination, or
hybrid, of any of the above examples or configurations. For
example, the waveform switch may be based on a number of channels
and a MIMO mode. In some cases, UE 115-a and base station 105-a may
be configured for MU-MIMO transmission and may use an SC-FDM
waveform. If UE 115-a and base station 105-a are configured for
SU-MIMO transmission, UE 115-a and base station 105-a may use
either an OFDM waveform, and transmit reference signals using an
OFDM or SC-FDM waveform. UE 115-a and base station 105-a may only
switch waveforms if UE 115-a is configured for SIMO communication.
If communicating on a single channel, UE 115-a and base station
105-a may transmit data on an SC-FDM waveform, and transmit
reference signals using an SC-FDM or OFDM waveform. If
communicating on multiple channels, UE 115-a and base station 105-a
transmit data using an OFDM waveform, and reference signal
transmissions may switch waveforms or may not switch waveforms.
PUCCH and SRS transmission may use an SC-FDM waveform.
[0077] A second hybrid waveform switching configuration may be
based on a link budget and a MIMO type. In a second hybrid waveform
switching configuration, link budget limited and low MCS UEs 115
may use an SC-FDM waveform. In some examples, the link budget
limited and low MCS UEs 115 may be configured for SIMO
transmission. High SNR UEs 115 configured for MU-MIMO transmission
may use an SC-FDM waveform. High SNR UEs 115 configured for SU-MIMO
transmission may use an OFDM waveform and transmit reference
signals using and OFDM waveform or an SC-FDM waveform. Switching
may occur for high SNR UEs 115 configured for SIMO transmission.
For a UE 115 communicating on a single channel, the UE 115 and base
station 105 may transmit data using an SC-FDM waveform, and
transmit reference signals using an SC-FDM or OFDM waveform. For a
UE 115 communicating on multiple channels, the UE 115 and base
station 105 may transmit data using an OFDM waveform, and the
reference signal waveform may or may not switch waveforms. UE 115-a
and base station 105-a may use SC-FDM waveform for PUCCH.
[0078] Thus, in another hybrid waveform switching configuration,
waveform switching may be based on a link budget, a MIMO mode, and
Doppler information. Link budget limited and low MCS UEs 115 may
use a localized SC-FDM waveform, and the waveform determination may
not be based on a MIMO mode or Doppler information. High SNR, high
Doppler shift UEs 115 may transmit data transmission using an OFDM
or SC-FDM waveform, and reference signals using OFDM waveforms.
High SNR, low Doppler UEs 115 configured for MU-MIMO transmission
may use an SC-FDM waveform. High SNR, low Doppler UEs 115
configured for SU-MIMO transmission may OFDM waveform and transmit
reference signals using an OFDM or SC-FDM waveform. Switching
waveforms may occur for high SNR, low Doppler UEs 115 configured
for SIMO transmission. A UE transmission on one channel may
transmit data using an SC-FDM waveform, and transmit reference
signals using an SC-FDM or OFDM waveform. PUCCH and SRS may use an
SC-FDM waveform.
[0079] Either UE 115-a or base station 105-a may initiate a
waveform switch. If base station 105-a to initiates the switch,
base station 105-a may indicate this to UE 115-a (e.g., through an
explicit grant). If UE 115-a initiates the waveform switch, UE
115-a may indicate the switch to base station 105-a by adding or
setting a bit in a transmission. UE 115-a may also switch waveforms
without sending an explicit indication to base station 105-a. In
this case, UE 115-a and base station 105-a may switch based on
mutually identifiable conditions. For example, with link budget
based switching, UE 115-a may switch waveforms at a certain MCS.
For Doppler based switching, base station 105-a and UE 115-a may
first sync Doppler information prior to switching.
[0080] UE 115-a may be able to switch waveforms based on a number
of channels without synchronizing channel information with the base
station. When CQI and SRS are transmitted, the CQI and SRs may
indicate channel information which be used to identify the switch
at both UE 115-a and base station 105-a. In some cases, ambiguity
may arise based on scheduling requests (SRs) and acknowledgement
(ACK) transmissions. An SR transmission may be random at base
station 105-a, and ACK transmissions may be missing at UE 115-a
while being expected at base station 105-a. In some examples, the
waveform may switch if UE 115-a has the opportunity to transmit on
more than one UL channel. In one example, base station 105-a may
blindly detect SRs and ACKs from UE 115-a, which may indicate the
number of channels. Base station 105-a may decode the SR/ACK first
and use an OFDM waveform to decode PUSCH if transmission of the
SR/ACK is detected. In another example, the waveform may only
switch when CQI and SRS are transmitted together with PUSCH.
[0081] FIG. 3A illustrates an example of a channel structure 300-a
for uplink channel multiplexing and waveform selection according to
one or more aspects of the present disclosure. As shown, channel
structure 300-a is representative of an uplink subframe spanning a
number of symbols in time and a number of sub-carriers in
frequency. The number of sub-carriers span an available bandwidth
305-a.
[0082] A portion of the number of symbols is allocated for a PDCCH
310-a and a portion of the number of symbols is also allocated for
a common uplink burst 315-a. The remainder of the number of symbols
is allocated for uplink burst 320-a over which a number of channels
for a UE may be transmitted. As shown in this example, bandwidth
305-a is divided into a number of different channel regions in the
uplink burst 320-a, which includes multiple PUCCH, PUSCH, and SRS
channels spanning the entire number of symbols allocated for the
uplink burst 320-a. Here, FDM is used to divide each of the
channels. In other words, each channel spans a given number of
sub-carriers of the bandwidth 305-a. In some examples, different
waveforms may be selected for the multiple channels. For example,
SC-FDM may be selected for one or more of the SRSs and OFDM may be
selected for one or more of the PUSCHs. The multiple channels are
also shown in a given pattern spanning the bandwidth 305-a and each
channel is disjoint from the other channels in frequency. Though
one pattern of channels is shown, any number of channels in any
pattern may be considered without departing from the scope of the
present disclosure.
[0083] FIG. 3B illustrates an example of a channel structure 300-b
for uplink channel multiplexing and waveform selection according to
one or more aspects of the present disclosure. As shown, channel
structure 300-b is representative of an uplink subframe spanning a
number of symbols in time and a number of sub-carriers in
frequency. The number of sub-carriers span an available bandwidth
305-b.
[0084] As in FIG. 3A, a portion of the number of symbols is
allocated for a PDCCH 310-b and a portion of the number of symbols
is also allocated for a common uplink burst 315-b. The remainder of
the number of symbols is allocated for uplink burst 320-b over
which a number of channels for a UE may be transmitted. As shown in
this example, bandwidth 305-b is divided into a number of different
channel regions in the uplink burst 320-b, which includes multiple
PUCCH, PUSCH, and SRS channels spanning the entire number of
symbols allocated for the uplink burst 320-b. Here, FDM and TDM is
used to divide each of the channels. In other words, each channel
spans a given number of sub-carriers of the bandwidth 305-a and may
also span only a portion of the symbols allocated for the uplink
burst 320-b. In some examples, CDM or SDM may be used to multiplex
the same channel types of different UEs in the same frequency band.
For example, different Chu sequence shifts may be used to CDM PUCCH
of different UEs in the same resource block. In some examples,
different waveforms may be selected for the multiple channels. For
example, SC-FDM may be selected for one or more of the SRSs and
OFDM may be selected for one or more of the PUSCHs. The multiple
channels are also shown in a given pattern spanning the bandwidth
305-a and each channel is disjoint from the other channels in
frequency, while some channels are also disjointed in time. For
example, an SRS and a PUSCH both span the same sub-carriers but
different symbols in time. Though one pattern of channels is shown
in this FDM and TDM division, any number of channels in any pattern
may be considered without departing from the scope of the present
disclosure.
[0085] FIG. 4A illustrates an example of a channel structure 400-a
for uplink channel multiplexing and waveform selection according to
one or more aspects of the present disclosure. As shown, channel
structure 400-a is representative of an uplink subframe spanning a
number of symbols in time and a number of sub-carriers in
frequency. The number of sub-carriers span an available bandwidth
405-a.
[0086] A portion of the number of symbols is allocated for a PDCCH
410-a and a portion of the number of symbols is also allocated for
a common uplink burst 415-a. The remainder of the number of symbols
is allocated for uplink burst 420-a over which a number of channels
for a UE may be transmitted. As shown in this example, multiple
channels including a PUCCH, a PUSCH, a URLCC, and an SRS span
varying sub-carriers and symbols in the uplink burst 420-a. In some
examples, different waveforms may be selected for the multiple
channels. For example, SC-FDM may be selected for one or more of
the SRSs and OFDM may be selected for one or more of the
PUSCHs.
[0087] In FIG. 4A, each channel is from the same UE, however,
according to this pattern, some symbols and sub-carriers within the
uplink burst 420-a are unused. Accordingly, as shown in FIG. 4B,
multiple UEs may be multiplexed in a single uplink burst. FIG. 4B
illustrates an example of a channel structure 400-b for uplink
channel multiplexing and waveform selection according to one or
more aspects of the present disclosure. As shown, channel structure
400-b is representative of an uplink subframe spanning a number of
symbols in time and a number of sub-carriers in frequency. The
number of sub-carriers span an available bandwidth 405-b.
[0088] As in FIG. 4A, a portion of the number of symbols is
allocated for a PDCCH 410-b and a portion of the number of symbols
is also allocated for a common uplink burst 415-b. The remainder of
the number of symbols is allocated for uplink burst 420-b over
which a number of channels for multiple UEs 115 may be transmitted.
As shown in this example, multiple PUCCH, PUSCH, URLCC, and SRS
channels span varying bandwidths and symbols. Further, multiple
channels for multiple UEs 115 (UE1, UE2, and UE3) are multiplexed
within the uplink burst 420-b. In some examples, different
waveforms may be selected for multiple channels or for different
UEs 115. For example, SC-FDM may be selected for UE1 PUCCH, and
OFDM may be selected for UE3 SRS.
[0089] The multiple channels are also shown in a given pattern over
the bandwidth 405-b and each channel spans varying subcarriers in
frequency and symbols in time. Though one pattern of channels is
shown, any number of channels in any pattern may be considered
without departing from the scope of the present disclosure.
[0090] FIG. 5 illustrates an example of a waveform switch 500 for
UL channel dynamic waveform switching in accordance with one or
more aspects of the present disclosure. Waveform switch 500 may
represent an example of uplink communication between a base station
105 and a UE 115 of FIGS. 1-2. The UE 115 and/or base station 105
may determine a switching mode and switch a waveform of an uplink
channel (e.g., PUSCH) based on the switching mode. Specifically,
waveform switch 500 represents an example in which begins
transmitting PUSCH 510 with an SC-FDM waveform and then transitions
to using an OFDM waveform for PUSCH 515 due to the presence of
PUCCH transmission 505.
[0091] A UE 115 may transmit a PUCCH transmission 505 using a first
waveform and transmission pattern. For example, the waveform may be
transmitted using an SC-FDM waveform. The UE 115 may then transmit
on a PUSCH 510 using the first waveform. For example, the UE 115
may transmit on the PUSCH 510 using an SC-FDM waveform. In other
examples, UE 115 may transmit the PUSCH 510 using an OFDM waveform.
In some examples, the UE 115 may decide to switch based on whether
the uplink channel is configured for frequency domain CDM. If the
UE 115 decides to switch, the UE 115 may decide a second waveform
based on one or more waveform switching parameters. For example,
the waveform switching parameters may be a MIMO mode, a number of
channels, a link budget, or Doppler information. In some examples,
the second waveform may be the same as the first waveform, as the
UE 115 may decide not to switch.
[0092] The UE 115 may then switch waveforms and transmit on a PUSCH
515 using a second waveform. In some cases, both the base station
105 and the UE 115 may identify the switch, and in some cases the
UE 115 may switch without indicating the switch to the base station
105. The second waveform may be an SC-FDM waveform or an OFDM
waveform.
[0093] FIG. 6 illustrates an example of a waveform switch in a TTI
600 for UL channel dynamic waveform switching in accordance with
one or more aspects of the present disclosure. Waveform switch in a
TTI 600 may include a base station 105 and a UE 115 of FIGS. 1-5.
The UE 115 may switch waveforms during a TTI. For example, the UE
115 may switch waveforms at the end of a TTI. Or, the UE 115 may
switch after a symbol within the TTI such that some symbols of the
TTI use a first waveform and some symbols of the TTI use a second
waveform. Specifically, waveform switch in a TTI 600 represents an
example in which begins transmitting PUSCH symbols 605 with an
SC-FDM waveform and then transitions to using an OFDM waveform for
a PUSCH symbols 610 due to the presence of SRS 615.
[0094] The UE 115 may transmit a first set of PUSCH symbols 605
using a first waveform. The first waveform may be, for example,
SC-FDM or OFDM. In some examples, the UE 115 may decide to switch
based on whether the uplink channel is configured for frequency
domain CDM. If the UE 115 decides to switch, the UE 115 may decide
a second waveform based on one or more waveform switching
parameters. For example, the waveform switching parameters may be a
MIMO mode, a number of channels, a link budget, a SNR, a MCS, or
Doppler information. In some examples, the second waveform may be
the same as the first waveform, as the UE 115 may decide not to
switch.
[0095] The UE 115 may transmit a second PUSCH symbols 610 using the
second waveform. In some examples, the UE 115 may transmit the
second PUSCH symbols at the end of a TTI or after a symbol within
the TTI. For example, if the first PUSCH symbols 605 and the second
PUSCH symbols 610 make up a subframe, some symbols of the subframe
(e.g., the first PUSCH symbols 605) may be transmitted using the
first waveform, and some symbols of the subframe (e.g., the second
PUSCH symbols 610) may be transmitted using the second
waveform.
[0096] The UE 115 may also transmit an SRS 615. The SRS 615 may be
transmitted using a waveform (e.g., SC-FDM) which may not be
affected by the PUSCH waveform switching. That is, although the
PUSCH waveform may switch, the waveform of the SRS 615 may not
switch. Switching the waveform of the PUSCH may also not affect the
orthogonality of the PUSCH with the SRS 615 or affect the
orthogonality of the SRS of the UE 115 with an SRS of another UE
115.
[0097] FIG. 7 illustrates an example of a process flow 700 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The process flow 700 may include
operations performed by UE 115-b and base station 105-b, which may
be examples of a UE 115 and a base station 105 described herein
with reference to FIGS. 1-6. Process flow 700 represents an example
in which UE 115-b autonomously switches from using one waveform to
another.
[0098] At operation 705, UE 115-b and base station 105-b may
communicate on an uplink channel (e.g., PUSCH) using a first
waveform. In some cases, the waveform may be an SC-FDM waveform (as
illustrated) or it may also be an OFDM waveform. In some cases, UE
115-b may also select a switching mode based on whether the channel
uses frequency domain CDM. That is, if the channel uses frequency
domain CDM it may not perform the operations of process flow
700.
[0099] At operation 710, UE 115-b may identify one or more
switching parameters as described herein. For example, the
switching parameters may include a MIMO mode, a number of channels,
a link budget, or Doppler information.
[0100] At operation 715, UE 115-b may autonomously select a second
waveform based on one or more of the switching parameters. That is,
UE 115-b may select the second waveform without receiving an
explicit switching indication from base station 105-b.
[0101] In some cases, at operation 720, UE 115-b may transmit a
waveform switching indication to base station 105-b. That is, after
determining that a switch is appropriate, UE 115-b may indicate
this to base station 105-b. However, in some cases, UE 115-b may
not indicate the switch to base station 105-b. Instead, both UE
115-b and base station 105-b may identify the switch independently
based on mutually identifiable parameters.
[0102] At operation 725, UE 115-b and base station 105-b may
communicate on the uplink channel using the second waveform. For
example, UE 115-b may transmit PUSCH using an SC-FDM waveform after
previously using an SC-FDM waveform.
[0103] FIG. 8 illustrates an example of a process flow 800 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The process flow 800 may include
operations performed by UE 115-c and base station 105-c, which may
be examples of a UE 115 and a base station 105 described herein
with reference to FIGS. 1-5. Process flow 800 represents an example
in which UE 115-c switches from using one waveform to another after
receiving an explicit indication from base station 105-c.
[0104] At operation 805, UE 115-c and base station 105-c may
communicate on an uplink channel (e.g., PUSCH) using a first
waveform. In some cases, the waveform may be an SC-FDM waveform (as
illustrated) or it may also be an OFDM waveform. In some cases, UE
115-b may also select a switching mode based on whether the channel
uses frequency domain CDM. That is, if the channel uses frequency
domain CDM it may not perform the operations of process flow
800.
[0105] At operation 810, base station 105-c may identify one or
more determine switching parameters. For example, the switching
parameters may include a MIMO mode, a number (or type) of channels
being transmitted, a link budget, or Doppler information.
[0106] At operation 815, base station 105-c may select a second
waveform based on the switching parameters as described herein. In
some cases, the second waveform may be the same as the first
waveform used to communicate in operation 805. However, in some
cases, the second waveform may be different from that used in
operation 805 (e.g., UE 115-c and base station 105-c may transition
from using an SC-FDM waveform to using an OFDM waveform).
[0107] At operation 820, base station 105-c may transmit a waveform
switching indication to UE 115-c. The waveform switching indication
may be an explicit indication so that UE 115-c knows which waveform
to use when communicating on the uplink channel.
[0108] At operation 825, UE 115-c and base station 105-c may
communicate on the uplink channel using the second waveform. For
example, UE 115-c may transmit PUSCH using an OFDM waveform after
previously transmitting the channel using SC-FDM.
[0109] FIG. 9 shows a block diagram 900 of a wireless device 905
that supports UL channel dynamic waveform switching in accordance
with various aspects of the present disclosure. Wireless device 905
may be an example of aspects of a UE 115 or base station 105 as
described with reference to FIG. 1. Wireless device 905 may include
receiver 910, waveform switching manager 915, and transmitter 920.
Wireless device 905 may also include a processor. Each of these
components may be in communication with one another (e.g., via one
or more buses).
[0110] Receiver 910 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to UL channel dynamic waveform switching, etc.).
Information may be passed on to other components of the device. The
receiver 910 may be an example of aspects of the transceiver 1235
described with reference to FIG. 12. Receiver 910 may communicate
on communicate on an uplink physical layer channel using a first
waveform, and communicate on the uplink physical layer channel
using the second waveform.
[0111] Waveform switching manager 915 may be an example of aspects
of the waveform switching manager 1215 described with reference to
FIG. 12. Waveform switching manager 915 may determine whether an
uplink physical layer channel is configured for frequency domain
CDM, select a waveform switching mode based on the determination of
whether the physical layer channel is configured for frequency
domain CDM, and identify a waveform for the physical layer channel
based on the waveform switching mode. The waveform switching
manager 915 may also select a second waveform based on one or more
waveform switching parameters.
[0112] Transmitter 920 may transmit signals generated by other
components of the device. In some examples, the transmitter 920 may
be collocated with a receiver 910 in a transceiver module. For
example, the transmitter 920 may be an example of aspects of the
transceiver 1235 described with reference to FIG. 12. The
transmitter 920 may include a single antenna, or it may include a
set of antennas.
[0113] Transmitter 920 may communicate on communicate on an uplink
physical layer channel using a first waveform, and communicate on
the uplink physical layer channel using the second waveform. In
some cases, communicating on the uplink physical layer channel
using the first waveform includes: transmitting a physical uplink
shared channel (PUSCH) during a first symbol of a TTI. In some
cases, communicating on the uplink physical layer channel using the
second waveform includes: transmitting the PUSCH during a second
symbol of the TTI. In some cases, the first waveform includes an
OFDM waveform and the second waveform includes a SC-FDM waveform.
In some cases, the first waveform includes a SC-FDM waveform and
the second waveform includes an OFDM.
[0114] FIG. 10 shows a block diagram 1000 of a wireless device 1005
that supports UL channel dynamic waveform switching in accordance
with various aspects of the present disclosure. Wireless device
1005 may be an example of aspects of a wireless device 905 or a UE
115 or base station 105 as described with reference to FIGS. 1 and
9. Wireless device 1005 may include receiver 1010, waveform
switching manager 1015, and transmitter 1020. Wireless device 1005
may also include a processor. Each of these components may be in
communication with one another (e.g., via one or more buses).
[0115] Receiver 1010 may receive information such as packets, user
data, or control information associated with various information
channels (e.g., control channels, data channels, and information
related to UL channel dynamic waveform switching, etc.).
Information may be passed on to other components of the device. The
receiver 1010 may be an example of aspects of the transceiver 1235
described with reference to FIG. 12.
[0116] Waveform switching manager 1015 may be an example of aspects
of the waveform switching manager 1215 described with reference to
FIG. 12. Waveform switching manager 1015 may also include CDM
component 1025, switching mode component 1030, and waveform
selection component 1035.
[0117] CDM component 1025 may determine whether an uplink physical
layer channel is configured for frequency domain CDM. For example,
CDM component 1025 may determine that the uplink physical layer
channel is not configured for frequency domain CDM, where the
waveform switching mode includes a switching mode, and determine
that the uplink physical layer channel is configured for frequency
domain CDM, where the waveform switching mode includes a
non-switching mode. In some cases, the uplink physical layer
channel includes a PUSCH.
[0118] Switching mode component 1030 may select a waveform
switching mode. In some cases the waveform switching mode may be
based on the determination of whether the physical layer channel is
configured for frequency domain CDM. In some cases, the waveform
switching mode includes one or more rules for selecting an OFDM
waveform or a SC-FDM waveform.
[0119] Waveform selection component 1035 may identify a waveform
for the physical layer channel based on the waveform switching
mode, switch the waveform for the uplink physical layer channel
based on the switching mode, maintain the identified waveform for
the uplink physical layer channel based on the non-switching mode,
and select a second waveform based on one or more waveform
switching parameters.
[0120] In some cases, the one or more waveform switching parameters
include at least two of a MIMO configuration, a number of channels,
a Doppler shift, and a link budget, a SNR, or a MCS. In some cases,
the second waveform is applied to data transmissions, reference
signal transmissions, or both. In some cases, the second waveform
is autonomously selected by a UE based on one or more waveform
switching parameters. In some cases, the second waveform is
identified by a base station independently of the UE.
[0121] Transmitter 1020 may transmit signals generated by other
components of the device. In some examples, the transmitter 1020
may be collocated with a receiver 1010 in a transceiver module. For
example, the transmitter 1020 may be an example of aspects of the
transceiver 1235 described with reference to FIG. 12. The
transmitter 1020 may include a single antenna, or it may include a
set of antennas.
[0122] FIG. 11 shows a block diagram 1100 of a waveform switching
manager 1115 that supports UL channel dynamic waveform switching in
accordance with various aspects of the present disclosure. The
waveform switching manager 1115 may be an example of aspects of a
waveform switching manager 915, a waveform switching manager 1015,
or a waveform switching manager 1215 described with reference to
FIGS. 9, 10, and 12. The waveform switching manager 1115 may
include CDM component 1120, switching mode component 1125, waveform
selection component 1130, MIMO component 1135, channel number
component 1140, Doppler component 1145, link budget component 1150,
sounding reference signal (SRS) component 1155, and waveform
indication component 1160. Each of these modules may communicate,
directly or indirectly, with one another (e.g., via one or more
buses).
[0123] CDM component 1120 may determine whether an uplink physical
layer channel is configured for frequency domain CDM, for example,
CDM component 1120 may determine that the uplink physical layer
channel is not configured for frequency domain CDM, where the
waveform switching mode includes a switching mode, and determine
that the uplink physical layer channel is configured for frequency
domain CDM, where the waveform switching mode includes a
non-switching mode.
[0124] Additionally or alternatively, switching mode component 1125
may select a waveform switching mode. Waveform selection component
1130 may identify a waveform for the physical layer channel based
on the waveform switching mode, switch the waveform for the uplink
physical layer channel based on the switching mode, maintain the
identified waveform for the uplink physical layer channel based on
the non-switching mode, and select a second waveform based on one
or more waveform switching parameters.
[0125] MIMO component 1135 may identify a change in a MIMO
configuration, where the one or more waveform switching parameters
include a parameter based on the MIMO configuration.
[0126] Channel number component 1140 may identify a number of
channels in a TTI of the uplink physical layer channel, where the
one or more waveform switching parameters include a parameter based
on the number of channels in the TTI. In some cases, the uplink
physical layer channel includes a PUSCH, and where identifying the
number of channels in the TTI includes: determining that a PUCCH
transmission or a SRS transmission is scheduled during the TTI.
[0127] Doppler component 1145 may identify a change in a Doppler
shift of a UE, where the one or more waveform switching parameters
include a parameter based on the Doppler shift of the UE. In some
cases, communicating on the uplink physical layer channel using the
second waveform includes: communicating using a multi-cluster
transmission pattern based on the change in the Doppler shift.
[0128] Link budget component 1150 may identify a change in a link
budget of a UE, where one or more waveform switching parameters
includes a parameter based on the link budget of the UE. In some
examples, the link budget may be an SNR of a UE, or an MCS of a UE.
Thus, in some cases, link budget component 1150 may also identify a
change in SNR of a UE, or a change in MCS of a UE. SRS component
1155 may transmit a SRS during the second symbol of the TTI, where
the second symbol of the TTI includes a last symbol of the TTI.
[0129] Waveform indication component 1160 may receive an indication
of the second waveform from a base station, where the second
waveform is selected based on the indication, receive an indication
of the second waveform from a UE, where the second waveform is
selected based on the indication, transmit an indication of the
second waveform to a UE, and transmit an indication of the second
waveform to a base station.
[0130] FIG. 12 shows a diagram of a system 1200 including a device
1205 that supports UL channel dynamic waveform switching in
accordance with various aspects of the present disclosure. Device
1205 may be an example of or include the components of wireless
device 905, wireless device 1005, or a UE 115 as described above,
e.g., with reference to FIGS. 1, 9 and 10. Device 1205 may include
components for bi-directional voice and data communications
including components for transmitting and receiving communications,
including UE waveform switching manager 1215, processor 1220,
memory 1225, software 1230, transceiver 1235, antenna 1240, and I/O
controller 1245. These components may be in electronic
communication via one or more busses (e.g., bus 1210). Device 1205
may communicate wirelessly with one or more base stations 105.
[0131] Processor 1220 may include an intelligent hardware device,
(e.g., a general-purpose processor, a digital signal processor
(DSP), a central processing unit (CPU), a microcontroller, an
application-specific integrated circuit (ASIC), an
field-programmable gate array (FPGA), a programmable logic device,
a discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, processor
1220 may be configured to operate a memory array using a memory
controller. In other cases, a memory controller may be integrated
into processor 1220. Processor 1220 may be configured to execute
computer-readable instructions stored in a memory to perform
various functions (e.g., functions or tasks supporting UL channel
dynamic waveform switching). 1220.
[0132] Memory 1225 may include random access memory (RAM) and read
only memory (ROM). The memory 1225 may store computer-readable,
computer-executable software 1230 including instructions that, when
executed, cause the processor to perform various functions
described herein. In some cases, the memory 1225 may contain, among
other things, a basic input/output system (BIOS) which may control
basic hardware and/or software operation such as the interaction
with peripheral components or devices.
[0133] Software 1230 may include code to implement aspects of the
present disclosure, including code to support UL channel dynamic
waveform switching. Software 1230 may be stored in a non-transitory
computer-readable medium such as system memory or other memory. In
some cases, the software 1230 may not be directly executable by the
processor but may cause a computer (e.g., when compiled and
executed) to perform functions described herein.
[0134] Transceiver 1235 may communicate bi-directionally, via one
or more antennas, wired, or wireless links as described above. For
example, the transceiver 1235 may represent a wireless transceiver
and may communicate bi-directionally with another wireless
transceiver. The transceiver 1235 may also include a modem to
modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
[0135] In some cases, the wireless device may include a single
antenna 1240. However, in some cases the device may have more than
one antenna 1240, which may be capable of concurrently transmitting
or receiving multiple wireless transmissions.
[0136] I/O controller 1245 may manage input and output signals for
device 1205. I/O controller 1245 may also manage peripherals not
integrated into device 1205. In some cases, I/O controller 1245 may
represent a physical connection or port to an external peripheral.
In some cases, I/O controller 1245 may utilize an operating system
such as iOS.RTM., ANDROID.RTM., MS-DOS.RTM., MS-WINDOWS.RTM.,
OS/2.RTM., UNIX.RTM., LINUX.RTM., or another known operating
system.
[0137] FIG. 13 shows a diagram of a system 1300 including a device
1305 that supports UL channel dynamic waveform switching in
accordance with various aspects of the present disclosure. Device
1305 may be an example of or include the components of wireless
device 1005, wireless device 1105, or a base station 105 as
described above, e.g., with reference to FIGS. 1, 10 and 11. Device
1305 may include components for bi-directional voice and data
communications including components for transmitting and receiving
communications, including base station waveform switching manager
1315, processor 1320, memory 1325, software 1330, transceiver 1335,
antenna 1340, network communications manager 1345, and base station
communications manager 1350. These components may be in electronic
communication via one or more busses (e.g., bus 1310). Device 1305
may communicate wirelessly with one or more UEs 115.
[0138] Processor 1320 may include an intelligent hardware device,
(e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, processor
1320 may be configured to operate a memory array using a memory
controller. In other cases, a memory controller may be integrated
into processor 1320. Processor 1320 may be configured to execute
computer-readable instructions stored in a memory to perform
various functions (e.g., functions or tasks supporting UL channel
dynamic waveform switching). 1320.
[0139] Memory 1325 may include RAM and ROM. The memory 1325 may
store computer-readable, computer-executable software 1330
including instructions that, when executed, cause the processor to
perform various functions described herein. In some cases, the
memory 1325 may contain, among other things, a BIOS which may
control basic hardware and/or software operation such as the
interaction with peripheral components or devices.
[0140] Software 1330 may include code to implement aspects of the
present disclosure, including code to support UL channel dynamic
waveform switching. Software 1330 may be stored in a non-transitory
computer-readable medium such as system memory or other memory. In
some cases, the software 1330 may not be directly executable by the
processor but may cause a computer (e.g., when compiled and
executed) to perform functions described herein.
[0141] Transceiver 1335 may communicate bi-directionally, via one
or more antennas, wired, or wireless links as described above. For
example, the transceiver 1335 may represent a wireless transceiver
and may communicate bi-directionally with another wireless
transceiver. The transceiver 1335 may also include a modem to
modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
[0142] In some cases, the wireless device may include a single
antenna 1340. However, in some cases the device may have more than
one antenna 1340, which may be capable of concurrently transmitting
or receiving multiple wireless transmissions.
[0143] Network communications manager 1345 may manage
communications with the core network (e.g., via one or more wired
backhaul links). For example, the network communications manager
1345 may manage the transfer of data communications for client
devices, such as one or more UEs 115.
[0144] Base station communications manager 1350 may manage
communications with other base station 105, and may include a
controller or scheduler for controlling communications with UEs 115
in cooperation with other base stations 105. For example, the base
station communications manager 1350 may coordinate scheduling for
transmissions to UEs 115 for various interference mitigation
techniques such as beamforming or joint transmission. In some
examples, base station communications manager 1350 may provide an
X2 interface within an LTE/LTE-A wireless communication network
technology to provide communication between base stations 105.
[0145] FIG. 14 shows a flowchart illustrating a method 1400 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1400
may be implemented by a UE 115 or base station 105 or its
components as described herein. For example, the operations of
method 1400 may be performed by a waveform switching manager as
described with reference to FIGS. 9 through 11. In some examples, a
UE 115 or base station 105 may execute a set of codes to control
the functional elements of the device to perform the functions
described below. Additionally or alternatively, the UE 115 or base
station 105 may perform aspects the functions described below using
special-purpose hardware.
[0146] At block 1405 the UE 115 or base station 105 may determine
whether an uplink physical layer channel is configured for
frequency domain CDM. The operations of block 1405 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1405 may be performed by a CDM component as described with
reference to FIGS. 9 through 11.
[0147] At block 1410 the UE 115 or base station 105 may select a
waveform switching mode based at least in part on the determination
of whether the physical layer channel is configured for frequency
domain CDM. The operations of block 1410 may be performed according
to the methods described with reference to FIGS. 1 through 6. In
certain examples, aspects of the operations of block 1410 may be
performed by a switching mode component as described with reference
to FIGS. 9 through 11.
[0148] At block 1415 the UE 115 or base station 105 may identify a
waveform for the physical layer channel based at least in part on
the waveform switching mode. The operations of block 1415 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1415 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0149] At block 1420 the UE 115 or base station 105 may communicate
on the physical layer channel using the identified waveform. The
operations of block 1420 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1420 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0150] FIG. 15 shows a flowchart illustrating a method 1500 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1500
may be implemented by a UE 115 or base station 105 or its
components as described herein. For example, the operations of
method 1500 may be performed by a waveform switching manager as
described with reference to FIGS. 9 through 11. In some examples, a
UE 115 or base station 105 may execute a set of codes to control
the functional elements of the device to perform the functions
described below. Additionally or alternatively, the UE 115 or base
station 105 may perform aspects the functions described below using
special-purpose hardware.
[0151] At block 1505 the UE 115 or base station 105 may determine
whether an uplink physical layer channel is configured for
frequency domain CDM. The operations of block 1505 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1505 may be performed by a CDM component as described with
reference to FIGS. 9 through 11.
[0152] At block 1510 the UE 115 or base station 105 may determine
that the uplink physical layer channel is not configured for
frequency domain CDM, where the waveform switching mode comprises a
switching mode. The operations of block 1510 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1510 may be performed by a CDM component as described with
reference to FIGS. 9 through 11.
[0153] At block 1515 the UE 115 or base station 105 may select a
waveform switching mode. The operations of block 1515 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1515 may be performed by a switching mode component as
described with reference to FIGS. 9 through 11.
[0154] At block 1520 the UE 115 or base station 105 may identify a
waveform for the physical layer channel based at least in part on
the waveform switching mode. The operations of block 1520 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1520 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0155] At block 1525 the UE 115 or base station 105 may switch the
waveform for the uplink physical layer channel based at least in
part on the switching mode. The operations of block 1525 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1525 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0156] At block 1530 the UE 115 or base station 105 may communicate
on the physical layer channel using the identified waveform. The
operations of block 1530 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1530 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0157] FIG. 16 shows a flowchart illustrating a method 1600 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1600
may be implemented by a UE 115 or base station 105 or its
components as described herein. For example, the operations of
method 1600 may be performed by a waveform switching manager as
described with reference to FIGS. 9 through 11. In some examples, a
UE 115 or base station 105 may execute a set of codes to control
the functional elements of the device to perform the functions
described below. Additionally or alternatively, the UE 115 or base
station 105 may perform aspects the functions described below using
special-purpose hardware.
[0158] At block 1605 the UE 115 or base station 105 may determine
whether an uplink physical layer channel is configured for
frequency domain CDM. The operations of block 1605 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1605 may be performed by a CDM component as described with
reference to FIGS. 9 through 11.
[0159] At block 1610 the UE 115 or base station 105 may determine
that the uplink physical layer channel is configured for frequency
domain CDM, where the waveform switching mode comprises a
non-switching mode. The operations of block 1610 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1610 may be performed by a CDM component as described with
reference to FIGS. 9 through 11.
[0160] At block 1615 the UE 115 or base station 105 may select a
waveform switching mode. The operations of block 1615 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1615 may be performed by a switching mode component as
described with reference to FIGS. 9 through 11.
[0161] At block 1620 the UE 115 or base station 105 may identify a
waveform for the physical layer channel based at least in part on
the waveform switching mode. The operations of block 1620 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1620 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0162] At block 1625 the UE 115 or base station 105 may maintain
the identified waveform for the uplink physical layer channel based
at least in part on the non-switching mode. The operations of block
1625 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 1625 may be performed by a waveform selection
component as described with reference to FIGS. 9 through 11.
[0163] At block 1630 the UE 115 or base station 105 may communicate
on the physical layer channel using the identified waveform. The
operations of block 1630 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1630 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0164] FIG. 17 shows a flowchart illustrating a method 1700 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1700
may be implemented by a UE 115 or base station 105 or its
components as described herein. For example, the operations of
method 1700 may be performed by a waveform switching manager as
described with reference to FIGS. 9 through 11. In some examples, a
UE 115 or base station 105 may execute a set of codes to control
the functional elements of the device to perform the functions
described below. Additionally or alternatively, the UE 115 or base
station 105 may perform aspects the functions described below using
special-purpose hardware.
[0165] At block 1705 the UE 115 or base station 105 may communicate
on an uplink physical layer channel using a first waveform. The
operations of block 1705 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1705 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0166] At block 1710 the UE 115 or base station 105 may select a
second waveform based at least in part on one or more waveform
switching parameters. The operations of block 1710 may be performed
according to the methods described with reference to FIGS. 1
through 6. In certain examples, aspects of the operations of block
1710 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0167] At block 1715 the UE 115 or base station 105 may communicate
on the uplink physical layer channel using the second waveform. The
operations of block 1715 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1715 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0168] FIG. 18 shows a flowchart illustrating a method 1800 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1800
may be implemented by a base station 105 or its components as
described herein. For example, the operations of method 1800 may be
performed by a waveform switching manager as described with
reference to FIGS. 9 through 11. In some examples, a base station
105 may execute a set of codes to control the functional elements
of the device to perform the functions described below.
Additionally or alternatively, the base station 105 may perform
aspects the functions described below using special-purpose
hardware.
[0169] At block 1805 the base station 105 may communicate on an
uplink physical layer channel using a first waveform. The
operations of block 1805 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1805 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0170] At block 1810 the base station 105 may select a second
waveform based at least in part on one or more waveform switching
parameters. The operations of block 1810 may be performed according
to the methods described with reference to FIGS. 1 through 6. In
certain examples, aspects of the operations of block 1810 may be
performed by a waveform selection component as described with
reference to FIGS. 9 through 11.
[0171] At block 1815 the base station 105 may transmit an
indication of the second waveform to a UE. The operations of block
1815 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 1815 may be performed by a waveform indication
component as described with reference to FIGS. 9 through 11.
[0172] At block 1820 the base station 105 may communicate on the
uplink physical layer channel using the second waveform. The
operations of block 1820 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 1820 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0173] FIG. 19 shows a flowchart illustrating a method 1900 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 1900
may be implemented by a UE 115 or its components as described
herein. For example, the operations of method 1900 may be performed
by a waveform switching manager as described with reference to
FIGS. 9 through 11. In some examples, a UE 115 may execute a set of
codes to control the functional elements of the device to perform
the functions described below. Additionally or alternatively, the
UE 115 may perform aspects the functions described below using
special-purpose hardware.
[0174] At block 1905 the UE 115 may communicate on an uplink
physical layer channel using a first waveform. The operations of
block 1905 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 1905 may be performed by a transmitter as
described with reference to FIGS. 9 through 11.
[0175] At block 1910 the UE 115 may receive an indication of a
second waveform from a base station, where the second waveform is
selected based at least in part on the indication. The operations
of block 1910 may be performed according to the methods described
with reference to FIGS. 1 through 6. In certain examples, aspects
of the operations of block 1910 may be performed by a waveform
indication component as described with reference to FIGS. 9 through
11.
[0176] At block 1915 the UE 115 may select the second waveform
based at least in part on one or more waveform switching parameters
(including the indication). The operations of block 1915 may be
performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 1915 may be performed by a waveform selection component as
described with reference to FIGS. 9 through 11.
[0177] At block 1920 the UE 115 may communicate on the uplink
physical layer channel using the second waveform. The operations of
block 1920 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 1920 may be performed by a transmitter as
described with reference to FIGS. 9 through 11.
[0178] FIG. 20 shows a flowchart illustrating a method 2000 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 2000
may be implemented by a UE 115 or its components as described
herein. For example, the operations of method 2000 may be performed
by a waveform switching manager as described with reference to
FIGS. 9 through 11. In some examples, a UE 115 may execute a set of
codes to control the functional elements of the device to perform
the functions described below. Additionally or alternatively, the
UE 115 may perform aspects the functions described below using
special-purpose hardware.
[0179] At block 2005 the UE 115 may communicate on an uplink
physical layer channel using a first waveform. The operations of
block 2005 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 2005 may be performed by a transmitter as
described with reference to FIGS. 9 through 11.
[0180] At block 2010 the UE 115 may select a second waveform based
at least in part on one or more waveform switching parameters. The
operations of block 2010 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 2010 may be performed by a
waveform selection component as described with reference to FIGS. 9
through 11.
[0181] At block 2015 the UE 115 may transmit an indication of the
second waveform to a base station. The operations of block 2015 may
be performed according to the methods described with reference to
FIGS. 1 through 6. In certain examples, aspects of the operations
of block 2015 may be performed by a waveform indication component
as described with reference to FIGS. 9 through 11.
[0182] At block 2020 the UE 115 may communicate on the uplink
physical layer channel using the second waveform. The operations of
block 2020 may be performed according to the methods described with
reference to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 2020 may be performed by a transmitter as
described with reference to FIGS. 9 through 11.
[0183] FIG. 21 shows a flowchart illustrating a method 2100 for UL
channel dynamic waveform switching in accordance with various
aspects of the present disclosure. The operations of method 2100
may be implemented by a base station 105 or its components as
described herein. For example, the operations of method 2100 may be
performed by a waveform switching manager as described with
reference to FIGS. 9 through 11. In some examples, a base station
105 may execute a set of codes to control the functional elements
of the device to perform the functions described below.
Additionally or alternatively, the base station 105 may perform
aspects the functions described below using special-purpose
hardware.
[0184] At block 2105 the base station 105 may communicate on an
uplink physical layer channel using a first waveform. The
operations of block 2105 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 2105 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0185] At block 2110 the base station 105 may receive an indication
of a second waveform from a UE, where the second waveform is
selected based at least in part on the indication. The operations
of block 2110 may be performed according to the methods described
with reference to FIGS. 1 through 6. In certain examples, aspects
of the operations of block 2110 may be performed by a waveform
indication component as described with reference to FIGS. 9 through
11.
[0186] At block 2115 the base station 105 may select the second
waveform based at least in part on one or more waveform switching
parameters (including the indication). The operations of block 2115
may be performed according to the methods described with reference
to FIGS. 1 through 6. In certain examples, aspects of the
operations of block 2115 may be performed by a waveform selection
component as described with reference to FIGS. 9 through 11.
[0187] At block 2120 the base station 105 may communicate on the
uplink physical layer channel using the second waveform. The
operations of block 2120 may be performed according to the methods
described with reference to FIGS. 1 through 6. In certain examples,
aspects of the operations of block 2120 may be performed by a
transmitter as described with reference to FIGS. 9 through 11.
[0188] It should be noted that the methods described above describe
possible implementations, and that the operations and the
operations may be rearranged or otherwise modified and that other
implementations are possible. Furthermore, aspects from two or more
of the methods may be combined.
[0189] Techniques described herein may be used for various wireless
communications systems such as CDMA, TDMA, FDMA, OFDMA, single
carrier frequency division multiple access (SC-FDMA), and other
systems. The terms "system" and "network" are often used
interchangeably. A CDMA system may implement a radio technology
such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.
CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000
Releases may be commonly referred to as CDMA2000 1.times.,
1.times., etc. IS-856 (TIA-856) is commonly referred to as CDMA2000
1.times.EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes
Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may
implement a radio technology such as Global System for Mobile
Communications (GSM).
[0190] An OFDMA system may implement a radio technology such as
Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of
Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunications system (UMTS). 3GPP LTE
and LTE-Advanced (LTE-A) are new releases of Universal Mobile
Telecommunications System (UMTS) that use E-UTRA. UTRA, E-UTRA,
UMTS, LTE, LTE-A, and Global System for Mobile communications (GSM)
are described in documents from the organization named "3rd
Generation Partnership Project" (3GPP). CDMA2000 and UMB are
described in documents from an organization named "3rd Generation
Partnership Project 2" (3GPP2). The techniques described herein may
be used for the systems and radio technologies mentioned above as
well as other systems and radio technologies. While aspects an LTE
system may be described for purposes of example, and LTE
terminology may be used in much of the description, the techniques
described herein are applicable beyond LTE applications.
[0191] In LTE/LTE-A networks, including such networks described
herein, the term evolved node B (eNB) may be generally used to
describe the base stations. The wireless communications system or
systems described herein may include a heterogeneous LTE/LTE-A
network in which different types of evolved node B (eNBs) provide
coverage for various geographical regions. For example, each eNB or
base station may provide communication coverage for a macro cell, a
small cell, or other types of cell. The term "cell" may be used to
describe a base station, a carrier or component carrier associated
with a base station, or a coverage area (e.g., sector, etc.) of a
carrier or base station, depending on context.
[0192] Base stations may include or may be referred to by those
skilled in the art as a base transceiver station, a radio base
station, an access point, a radio transceiver, a NodeB, eNodeB
(eNB), Home NodeB, a Home eNodeB, or some other suitable
terminology. The geographic coverage area for a base station may be
divided into sectors making up only a portion of the coverage area.
The wireless communications system or systems described herein may
include base stations of different types (e.g., macro or small cell
base stations). The UEs described herein may be able to communicate
with various types of base stations and network equipment including
macro eNBs, small cell eNBs, relay base stations, and the like.
There may be overlapping geographic coverage areas for different
technologies.
[0193] A macro cell generally covers a relatively large geographic
area (e.g., several kilometers in radius) and may allow
unrestricted access by UEs with service subscriptions with the
network provider. A small cell is a lower-powered base station, as
compared with a macro cell, that may operate in the same or
different (e.g., licensed, unlicensed, etc.) frequency bands as
macro cells. Small cells may include pico cells, femto cells, and
micro cells according to various examples. A pico cell, for
example, may cover a small geographic area and may allow
unrestricted access by UEs with service subscriptions with the
network provider. A femto cell may also cover a small geographic
area (e.g., a home) and may provide restricted access by UEs having
an association with the femto cell (e.g., UEs in a closed
subscriber group (CSG), UEs for users in the home, and the like).
An eNB for a macro cell may be referred to as a macro eNB. An eNB
for a small cell may be referred to as a small cell eNB, a pico
eNB, a femto eNB, or a home eNB. An eNB may support one or multiple
(e.g., two, three, four, and the like) cells (e.g., component
carriers). A UE may be able to communicate with various types of
base stations and network equipment including macro eNBs, small
cell eNBs, relay base stations, and the like.
[0194] The wireless communications system or systems described
herein may support synchronous or asynchronous operation. For
synchronous operation, the base stations may have similar frame
timing, and transmissions from different base stations may be
approximately aligned in time. For asynchronous operation, the base
stations may have different frame timing, and transmissions from
different base stations may not be aligned in time. The techniques
described herein may be used for either synchronous or asynchronous
operations.
[0195] The downlink transmissions described herein may also be
called forward link transmissions while the uplink transmissions
may also be called reverse link transmissions. Each communication
link described herein--including, for example, wireless
communications system 100 and 200 of FIGS. 1 and 2--may include one
or more carriers, where each carrier may be a signal made up of
multiple sub-carriers (e.g., waveform signals of different
frequencies).
[0196] The description set forth herein, in connection with the
appended drawings, describes example configurations and does not
represent all the examples that may be implemented or that are
within the scope of the claims. The term "exemplary" used herein
means "serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, well-known structures and devices are shown in block
diagram form in order to avoid obscuring the concepts of the
described examples.
[0197] In the appended figures, similar components or features may
have the same reference label. Further, various components of the
same type may be distinguished by following the reference label by
a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label.
[0198] Information and signals described herein may be represented
using any of a variety of different technologies and techniques.
For example, data, instructions, commands, information, signals,
bits, symbols, and chips that may be referenced throughout the
above description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields
or particles, or any combination thereof.
[0199] The various illustrative blocks and modules described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a DSP, an ASIC, an FPGA
or other programmable logic device, discrete gate or transistor
logic, discrete hardware components, or any combination thereof
designed to perform the functions described herein. A
general-purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices (e.g., a
combination of a DSP and a microprocessor, multiple
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration).
[0200] The functions described herein may be implemented in
hardware, software executed by a processor, firmware, or any
combination thereof. If implemented in software executed by a
processor, the functions may be stored on or transmitted over as
one or more instructions or code on a computer-readable medium.
Other examples and implementations are within the scope of the
disclosure and appended claims. For example, due to the nature of
software, functions described above can be implemented using
software executed by a processor, hardware, firmware, hardwiring,
or combinations of any of these. Features implementing functions
may also be physically located at various positions, including
being distributed such that portions of functions are implemented
at different physical locations. Also, as used herein, including in
the claims, "or" as used in a list of items (for example, a list of
items prefaced by a phrase such as "at least one of" or "one or
more of") indicates an inclusive list such that, for example, a
phrase referring to "at least one of" a list of items refers to any
combination of those items, including single members. As an
example, "at least one of: A, B, or C" is intended to cover A, B,
C, A-B, A-C, B-C, and A-B-C, as well as any combination with
multiples of the same element (e.g., A-A A-A-A, A-A-B, A-A-C,
A-B-B, A-C-C, B-B, B-B-B, B-B-C, C-C, and C-C-C or any other
ordering of A, B, and C).
[0201] Also, as used herein, the phrase "based on" shall not be
construed as a reference to a closed set of conditions. For
example, an exemplary operation that is described as "based on
condition A" may be based on both a condition A and a condition B
without departing from the scope of the present disclosure. In
other words, as used herein, the phrase "based on" shall be
construed in the same manner as the phrase "based at least in part
on."
[0202] Computer-readable media includes both non-transitory
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A non-transitory storage medium may be any available
medium that can be accessed by a general purpose or special purpose
computer. By way of example, and not limitation, non-transitory
computer-readable media may comprise RAM, ROM, electrically
erasable programmable read only memory (EEPROM), compact disk (CD)
ROM or other optical disk storage, magnetic disk storage or other
magnetic storage devices, or any other non-transitory medium that
can be used to carry or store desired program code means in the
form of instructions or data structures and that can be accessed by
a general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
digital subscriber line (DSL), or wireless technologies such as
infrared, radio, and microwave are included in the definition of
medium. Disk and disc, as used herein, include CD, laser disc,
optical disc, digital versatile disc (DVD), floppy disk and Blu-ray
disc where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above are
also included within the scope of computer-readable media.
[0203] The description herein is provided to enable a person
skilled in the art to make or use the disclosure. Various
modifications to the disclosure will be readily apparent to those
skilled in the art, and the generic principles defined herein may
be applied to other variations without departing from the scope of
the disclosure. Thus, the disclosure is not limited to the examples
and designs described herein, but is to be accorded the broadest
scope consistent with the principles and novel features disclosed
herein.
* * * * *