U.S. patent application number 16/442862 was filed with the patent office on 2019-10-03 for system and method for machine-type communications.
The applicant listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Javad Abdoli, Yu Cao, Ming Jia, Jianglei Ma.
Application Number | 20190306683 16/442862 |
Document ID | / |
Family ID | 54192358 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190306683 |
Kind Code |
A1 |
Cao; Yu ; et al. |
October 3, 2019 |
System and Method for Machine-Type Communications
Abstract
A method for operating a machine-type device (MTD) includes
determining communications requirements for a machine-type device
(MTD), and assigning a first signal waveform selected from a
plurality of signal waveforms to the MTD in accordance with the
determined communications requirements, wherein each signal
waveform has an associated characteristic signal bandwidth.
Inventors: |
Cao; Yu; (Ottawa, CA)
; Jia; Ming; (Ottawa, CA) ; Ma; Jianglei;
(Ottawa, CA) ; Abdoli; Javad; (Kanata,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Shenzhen |
|
CN |
|
|
Family ID: |
54192358 |
Appl. No.: |
16/442862 |
Filed: |
June 17, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15600538 |
May 19, 2017 |
10327122 |
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16442862 |
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14228187 |
Mar 27, 2014 |
9693172 |
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15600538 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/0003 20130101;
H04W 72/048 20130101; H04W 28/0284 20130101; H04W 4/70 20180201;
H04W 28/02 20130101; H04L 1/0009 20130101; H04J 14/02 20130101 |
International
Class: |
H04W 4/70 20060101
H04W004/70; H04W 28/02 20060101 H04W028/02; H04W 72/04 20060101
H04W072/04; H04L 1/00 20060101 H04L001/00; H04J 14/02 20060101
H04J014/02 |
Claims
1. A method comprising: transmitting, by a base station,
information about a first narrow-band signal waveform to a
machine-type device (MTD) configured to perform machine-type
communications (MTC), the first narrow-band signal waveform
obtained from a plurality of signal waveforms; and communicating,
by the base station with the MTD, data using the first narrow-band
signal waveform.
2. The method of claim 1, further comprising: obtaining, by the
base station, communications requirements for the MTD, wherein the
first narrow-band signal waveform is selected from the plurality of
signal waveforms in accordance with the obtained communications
requirements.
3. The method of claim 1, wherein the communicating comprises:
receiving, by the base station, a packet from the MTD, wherein the
packet is transmitted using the first narrow-band signal
waveform.
4. The method of claim 3, wherein the information about the first
narrow-band signal waveform comprises transmission characteristics
of a communications channel used to transmit the packet using the
first narrow-band signal waveform.
5. The method of claim 4, wherein the transmission characteristics
comprise at least one of a bandwidth associated with the MTD, and a
level of a modulation and coding scheme (MCS) used for
transmission.
6. The method of claim 5, further comprising: altering the
transmission characteristics of the communications channel in
accordance with at least one of a channel condition of the
communications channel, and a system load of the base station;
assigning a second narrow-band signal waveform selected from the
plurality of signal waveforms to the MTD in accordance with the
altered transmission characteristics; and transmitting information
about the second narrow-band signal waveform to the MTD.
7. The method of claim 6, wherein altering the transmission
characteristics comprises: increasing the level of the MCS in
response to determining that the system load of the base station is
overloaded; and increasing the bandwidth associated with the MTD in
response to determining that the system load of the base station is
underloaded.
8. The method of claim 7, wherein the increasing the level of the
MCS further comprises reducing the bandwidth associated with the
MTD.
9. The method of claim 7, wherein the increasing the bandwidth
associated with the MTD further comprises reducing the level of the
MCS.
10. The method of claim 1, wherein the first narrow-band signal
waveform is selected from the plurality of signal waveforms in
accordance with communications requirements of the MTD, and the
communications requirements comprise at least one of a coverage
requirement, a communications system load, MTD geometry, MTD power
consumption, a frequency of transmissions made by the MTD, a
bandwidth requirement of the MTD, an amount of data to be
transmitted by the MTD, a priority level of the MTD, and a priority
level of transmissions made by the MTD.
11. The method of claim 1, wherein the first narrow-band signal
waveform has a characteristic signal bandwidth that is narrow
enough such that no repetition coding is needed for the base
station to provide enhanced coverage to the MTD.
12. A method comprising: receiving, by a machine-type device (MTD)
configured to perform machine-type communications (MTC), from a
base station, information about a first narrow-band signal
waveform, the first narrow-band signal waveform obtained from a
plurality of signal waveforms; and communicating, by the MTD with
the base station, data using the first narrow-band signal
waveform.
13. The method of claim 12, wherein the communicating comprises:
transmitting, by the MTD, a packet to the base station using the
first narrow-band signal waveform.
14. The method of claim 13, wherein the information about the first
narrow-band signal waveform comprises transmission characteristics
of a communications channel used to transmit the packet using the
first narrow-band signal waveform.
15. The method of claim 14, wherein the transmission
characteristics comprise at least one of a bandwidth associated
with the MTD, and a level of a modulation and coding scheme (MCS)
used for transmission.
16. The method of claim 12, wherein the first narrow-band signal
waveform has a characteristic signal bandwidth that is narrow
enough such that no repetition coding is needed for the base
station to provide enhanced coverage to the MTD.
17. The method of claim 12, further comprising: transmitting
communications requirements to the base station, wherein the
communications requirements are used to obtain the first
narrow-band signal waveform.
18. The method of claim 17, wherein the communications requirements
comprise at least one of a coverage requirement, a communications
system load, MTD geometry, MTD power consumption, a frequency of
transmissions made by the MTD, a bandwidth requirement of the MTD,
an amount of data to be transmitted by the MTD, a priority level of
the MTD, and a priority level of transmissions made by the MTD.
19. A base station comprising: a non-transitory computer-readable
memory; and a processor coupled to the non-transitory
computer-readable memory and configured to: transmit information
about a first narrow-band signal waveform to a machine-type device
(MTD) configured to perform machine-type communications (MTC)
communications, the first narrow-band signal waveform obtained from
a plurality of signal waveforms; and communicate, with the MTD,
data using the first narrow-band signal waveform.
20. The base station of claim 19, wherein the processor is further
configured to: obtain communications requirements for the MTD, and
wherein the first narrow-band signal waveform is selected from the
plurality of signal waveforms in accordance with the communications
requirements for the MTD.
21. The base station of claim 19, wherein the processor is
configured to: receive a packet from the MTD, wherein the packet is
transmitted using the first narrow-band signal waveform.
22. The base station of claim 21, wherein the information about the
first narrow-band signal waveform comprises transmission
characteristics of a communications channel used to transmit the
packet using the first narrow-band signal waveform, and the
transmission characteristics comprise at least one of a bandwidth
associated with the MTD, and a level of a modulation and coding
scheme (MCS) used for transmission.
23. The base station of claim 22, wherein the processor is
configured to: alter the transmission characteristics of the
communications channel in accordance with at least one of a channel
condition of the communications channel, and a system load of the
base station, assign a second narrow-band signal waveform selected
from the plurality of signal waveforms to the MTD in accordance
with the altered transmission characteristics, and transmit
information about the second narrow-band signal waveform to the
MTD.
24. The base station of claim 23, wherein the processor is
configured to increase the level of the MCS in response to
determining that the system load of the base station is overloaded,
and to increase the bandwidth allocated to the MTD in response to
determining that the system load of the base station is
underloaded.
25. The base station of claim 19, wherein the first narrow-band
signal waveform is selected from the plurality of signal waveforms
in accordance with communications requirements of the MTD, and the
communications requirements comprise at least one of a coverage
requirement, a communications system load, MTD geometry, MTD power
consumption, a frequency of transmissions made by the MTD, a
bandwidth requirement of the MTD, an amount of data to be
transmitted by the MTD, a priority level of the MTD, and a priority
level of transmissions made by the MTD.
26. A machine-type device (MTD) configured to perform machine-type
communications (MTC), the MTD comprising: a non-transitory
computer-readable memory; and a processor coupled to the
non-transitory computer-readable memory and configured to: receive,
from a base station, information about a first narrow-band signal
waveform, the first narrow-band signal waveform obtained from a
plurality of signal waveforms; and communicate, with the base
station, data using the first narrow-band signal waveform.
27. The MTD of claim 26, wherein the processor is configured to:
transmit a packet to the base station using the first narrow-band
signal waveform.
28. The MTD of claim 27, wherein the information about the first
narrow-band signal waveform comprises transmission characteristics
of a communications channel used to transmit the packet using the
first narrow-band signal waveform.
29. The MTD of claim 28, wherein the transmission characteristics
comprise at least one of a bandwidth associated with the MTD, and a
level of a modulation and coding scheme (MCS) used for
transmission.
30. The MTD of claim 26, wherein the processor is further
configured to: transmit communications requirements to the base
station, wherein the communications requirements are used to obtain
the first narrow-band signal waveform.
31. The MTD of claim 30, wherein the communications requirements of
the MTD comprise at least one of a coverage requirement, a
communications system load, MTD geometry, MTD power consumption, a
frequency of transmissions made by the MTD, a bandwidth requirement
of the MTD, an amount of data to be transmitted by the MTD, a
priority level of the MTD, and a priority level of transmissions
made by the MTD.
32. The MTD of claim 26, wherein the first narrow-band signal
waveform has a characteristic signal bandwidth that is narrow
enough such that no repetition coding is needed for the base
station to provide enhanced coverage to the MTD.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/600,538, entitled "System and Method for
Machine-Type Communications," filed May 19, 2017, which is a
continuation of U.S. patent application Ser. No. 14/228,187,
entitled "System and Method for Machine-Type Communications," filed
Mar. 27, 2014, which applications are hereby incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to digital
communications, and more particularly to a system and method for
machine-type communications (MTC).
BACKGROUND
[0003] In general, machine-to-machine (M2M) communications refer to
connectivity between a large number of machine-type devices that
communicate with each other or with a connected service without
need for human intervention. In M2M communications, also commonly
referred to as machine-type communications (MTC), machines
(devices) can directly communicate with one another or can make use
of a common network, such as the Internet.
[0004] The M2M market is quickly growing and some forecasts
estimate that billions of machine-type devices will be deployed in
the coming decade. Applications for these machine-type devices
include smart metering, smart grid, surveillance, security,
vehicle-to-vehicle communications, intelligent transportation
system (ITS), e-health, industrial Internet, cloud computing, and
the like.
[0005] Some of the challenges for MTC include:
[0006] 1) Massive Connections. The number of connected MTC devices
is growing. It is expected the number of deployed MTC devices will
increase by at least an order of magnitude within a decade. Many of
these devices will rely upon a connection to a wireless network
which may overwhelm current Long Term Evolution (LTE) based
wireless networks;
[0007] 2) High coverage for supporting remote sensors. It has been
estimated that the link budget of a network supporting a large
number of MTC devices will need to be 15 dB to 20 dB above GSM
900/UMTS 900/LTE 800;
[0008] 3) Cost of hardware. Due to large number of meters and
sensors, the cost per device needs to be low to enable successful
commercial deployment. It is expected that the per device cost will
need to be in the range of one to two dollars to achieve wide scale
commercial use;
[0009] 4) Power Consumption. Many meters and sensors are expected
to be powered by batteries and some may have only intermittent
access to other power sources. Due to the cost constraints and
power limitations, it is expected that MTC devices may require a
standby time in the target of several years for a single battery;
and
[0010] 5) Asynchronous transmission mode. Currently deployed
wireless networks typically rely upon device synchronizing with a
base station to synchronize transmissions to defined time windows.
This can be burdensome to implement in a low cost device with
limited power supply. A reduction in signaling overhead caused by
the need for synchronous transmissions would also be desirable.
[0011] Therefore, there is a need for a system and a method for
supporting MTC with large numbers of machine-type devices while
meeting the challenges described above.
SUMMARY OF THE DISCLOSURE
[0012] Example embodiments of the present disclosure which provide
a system and method for machine-type communications (MTC).
[0013] In accordance with embodiments, a base station transmits
information about a first narrow-band signal waveform to a
machine-type device (MTD) configured to perform machine-type
communications (MTC). The first narrow-band signal waveform is
obtained from a plurality of signal waveforms. The base station
communicates data using the first narrow-band signal waveform.
[0014] In some embodiments, the base station obtains communications
requirements for the MTD. The first narrow-band signal waveform is
selected from the plurality of signal waveforms in accordance with
the obtained communications requirements.
[0015] In some embodiments, the base station communicates data by
receiving a packet from the MTD. The packet is transmitted using
the first narrow-band signal waveform.
[0016] In some embodiments, the information about the first
narrow-band signal waveform comprises transmission characteristics
of a communications channel used to transmit the packet using the
first narrow-band signal waveform. In some embodiments, the
transmission characteristics comprise at least one of a bandwidth
associated with the MTD, and a level of a modulation and coding
scheme (MCS) used for transmission.
[0017] In some embodiments, the base station alters the
transmission characteristics of the communications channel in
accordance with at least one of a channel condition of the
communications channel, and a system load of the base station. The
base station assigns a second narrow-band signal waveform selected
from the plurality of signal waveforms to the MTD in accordance
with the altered transmission characteristics. The base station
transmits information about the second narrow-band signal waveform
to the MTD.
[0018] In some embodiments, the base station alters the
transmission characteristics by increasing the level of the MCS in
response to determining that the system load of the base station is
overloaded and increasing the bandwidth associated with the MTD in
response to determining that the system load of the base station is
underloaded.
[0019] In some embodiments, the base station increases the level of
the MCS by reducing the bandwidth associated with the MTD. In some
embodiments, the base station increases the bandwidth associated
with the MTD by reducing the level of the MCS.
[0020] In some embodiments, the first narrow-band signal waveform
is selected from the plurality of signal waveforms in accordance
with communications requirements of the MTD, and the communications
requirements comprise at least one of a coverage requirement, a
communications system load, MTD geometry, MTD power consumption, a
frequency of transmissions made by the MTD, a bandwidth requirement
of the MTD, an amount of data to be transmitted by the MTD, a
priority level of the MTD, and a priority level of transmissions
made by the MTD.
[0021] In some embodiments, the first narrow-band signal waveform
has a characteristic signal bandwidth that is narrow enough such
that no repetition coding is needed for the base station to provide
enhanced coverage to the MTD.
[0022] In accordance with embodiments, a machine-type device (MTD)
configured to perform machine-type communications (MTC) receives
from a base station, information about a first narrow-band signal
waveform, the first narrow-band signal waveform obtained from a
plurality of signal waveforms. The MTD communicates, with the base
station, data using the first narrow-band signal waveform.
[0023] In some embodiments, the MTD communicates data by
transmitting a packet to the base station using the first
narrow-band signal waveform.
[0024] In some embodiments, the information about the first
narrow-band signal waveform comprises transmission characteristics
of a communications channel used to transmit the packet using the
first narrow-band signal waveform.
[0025] In some embodiments, the transmission characteristics
comprise at least one of a bandwidth associated with the MTD, and a
level of a modulation and coding scheme (MCS) used for
transmission.
[0026] In some embodiments, the first narrow-band signal waveform
has a characteristic signal bandwidth that is narrow enough such
that no repetition coding is needed for the base station to provide
enhanced coverage to the MTD.
[0027] In some embodiments, the MTD transmits communications
requirements to the base station. The communications requirements
are used to obtain the first narrow-band signal waveform.
[0028] In some embodiments, the communications requirements
comprise at least one of a coverage requirement, a communications
system load, MTD geometry, MTD power consumption, a frequency of
transmissions made by the MTD, a bandwidth requirement of the MTD,
an amount of data to be transmitted by the MTD, a priority level of
the MTD, and a priority level of transmissions made by the MTD.
[0029] One advantage of an embodiment is that large numbers of
machine-type devices are supported while maintaining low hardware
costs and low power requirements.
[0030] A further advantage of an embodiment is that large coverage
areas are supported by allowing communications to occur at low
signal power levels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] For a more complete understanding of the present disclosure,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawing, in
which:
[0032] FIG. 1a illustrates a portion of a first example
communications system according to example embodiments described
herein;
[0033] FIG. 1b illustrates a portion of a second example
communications system highlight MTDs and MTC according to example
embodiments described herein;
[0034] FIG. 1c illustrates a portion of a third example
communications system highlighting coverage range with MTDs and MTC
according to example embodiments described herein;
[0035] FIG. 2 illustrates a plot of example transmissions made by a
plurality of MTDs according to example embodiments described
herein;
[0036] FIG. 3 illustrates a flow diagram of example operations
occurring in an eNB as the eNB participates in MTC according to
example embodiments described herein;
[0037] FIG. 4 illustrates a diagram of example communications
resources in a 3GPP LTE communications system according to example
embodiments described herein;
[0038] FIG. 5 illustrates a flow diagram of example operations
occurring in a MTD as the MTD participates in MTC according to
example embodiments described herein;
[0039] FIG. 6 illustrates a diagram of a communications system that
supports adjustable bandwidth for MTDs according to example
embodiments described herein;
[0040] FIG. 7 illustrates a flow diagram of example operations
occurring in an eNB as the eNB adjusts the channel characteristics
of channels of MTDs according to example embodiments described
herein;
[0041] FIG. 8 illustrates an example first communications device
according to example embodiments described herein; and
[0042] FIG. 9 illustrates an example second communications device
according to example embodiments described herein.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0043] The operating of the current example embodiments and the
structure thereof are discussed in detail below. It should be
appreciated, however, that the present disclosure provides many
applicable inventive concepts that can be embodied in a wide
variety of specific contexts. The specific embodiments discussed
are merely illustrative of specific structures of the disclosure
and ways to operate the disclosure, and do not limit the scope of
the disclosure.
[0044] One embodiment of the disclosure relates to machine-type
communications (MTC). For example, a communication controller
determines communications requirements for a machine-type device
(MTD), and assigns a first signal waveform selected from a
plurality of signal waveforms to the MTD in accordance with the
communications requirements for the MTD, where each signal waveform
has an associated characteristic signal bandwidth. The
communication controller also transmits information about the first
signal waveform to the MTD, and receives a packet from the MTD,
wherein the packet is transmitted using the first signal
waveform.
[0045] The present disclosure will be described with respect to
example embodiments in a specific context, namely communications
systems that support MTC for machine-type devices. The disclosure
may be applied to standards compliant communications systems, such
as those that are compliant with Third Generation Partnership
Project (3GPP), IEEE 802.11, and the like, technical standards, and
non-standards compliant communications systems, that support MTC
for machine-type devices.
[0046] FIG. 1a illustrates a portion of a first example
communications system 100. Communications system 100 may include an
evolved NodeB (eNB) 105 operating as a communications controller.
Communications system 100 may also include user equipment (UE),
such as UE 110 and UE 112, as well as machine-type device (MTD),
such as MTD 114 and MTD 116. In general, an eNB may also be
referred to as a communications controller, a NodeB, a base
station, a controller, and the like. Similarly, a UE may also be
referred to as a mobile station, a mobile, a terminal, a user, a
subscriber, and the like. Communications system 100 may also
include a relay node (RN) 118 that is capable of utilizing a
portion of resources of eNB 105 to help improve coverage and/or
overall performance of communications system 100.
[0047] While it is understood that communications systems may
employ multiple eNBs capable of communicating with a number of
devices, only one eNB, one RN, and a number of UEs and MTDs are
illustrated for simplicity.
[0048] One common application for MTD and MTC involves the use of
MTDs as sensors that occasionally and/or periodically report
information to a centralized entity through MTC with an eNB.
Examples of such an application may include e-health monitors,
smart meters, security system monitors, fire monitors, weather
monitors, home automation monitors, vehicle monitors, and the like.
In such an application, the MTDs generally have very low data
bandwidth requirements since their reports are usually on the order
of tens or hundreds of bytes in size and normally occur
infrequently. Although individual MTDs have low communications
requirements, they are typically deployed in very large numbers.
Hence, the overall communications requirements may be large and
difficult to handle effectively.
[0049] FIG. 1b illustrates a portion of a second example
communications system 150 highlight MTDs and MTC. Communications
system 150 includes an eNB 155 serving both UEs and MTDs. As
discussed previously, individual MTDs may have low communications
requirements when compared to UEs. However, when there are large
numbers of MTDs, their collective communications requirements may
be very large and hard to handle in an efficient manner. As shown
in FIG. 1b, eNB 155 is serving a MTD 160 that is a part of an
intelligent vehicle system, a MTD 162 that is a smart meter, a MTD
164 that is part of an e-health system, and a UE 166. It is noted
that communications system 150 may include other UEs and MTDs, but
only a limited number are illustrated to simplify discussion.
[0050] Depending on applications executing on UE 166,
communications between eNB 155 and UE 166 may be interactive and
involve large numbers of uplink (communications from UE 166 to eNB
155) and downlink (communications from eNB 155 to UE 166)
transmissions. As an illustrative example, if UE 166 is streaming a
video and providing constant social media updates, hundreds of
megabytes of information may be exchanged between eNB 155 and UE
166 in a small period of time.
[0051] However, MTC between eNB 155 and the MTD that it is serving
may involve a much smaller amount of data. As an illustrative
example, MTD 162 may transmit power usage information to eNB 155
(which will forward the information to a server associated with MTD
162) once every few seconds, few tens of seconds, or few minutes.
Furthermore, the power usage information may only a few bytes in
size. Similarly, MTD 164 may transmit health information to eNB 155
only if it detects an anomaly in the health information of a
patient it is monitoring. Therefore, most of the time, MTD 164 may
not even have to transmit any information. However, there may be a
large number of MTD, hence, the resultant MTC requirements may be
large and hard to handle efficiently.
[0052] FIG. 1c illustrates a portion of a third example
communications system 175 highlighting coverage range with MTDs and
MTC. Communications system 175 includes an eNB 180 serving a first
MTD 185 and a second MTD 187. First MTD 185 is operating relatively
close to eNB 180, while second MTD 187 is operating remotely from
eNB 180. Since second MTD 187 is located far away from eNB 180
(when compared to first MTD 185), extended coverage (or similarly,
extended range) is needed to provide coverage for second MTD
187.
[0053] In a cellular communications system, such as a 3GPP Long
Term Evolution (LTE) compliant communications, uplink transmissions
from various UE are adjusted with respect to timing to help ensure
that the transmission arrive at the eNB at substantially the same
time. The strict synchronous operation requirement arises from the
rectangular pulses used in orthogonal frequency division
multiplexed (OFDM) that present large side lobes in the frequency
domain. Therefore, communications systems utilizing OFDM require
synchronization in the time domain and the frequency domain to
retain orthogonality among the different subcarriers.
[0054] However, for MTDs, which may be inactive for extended
amounts of time, maintaining synchrony may be difficult and may
require a significant amount of additional complexity. Furthermore,
MTC traffic usually occurs in short packets, and the signaling
overhead associated with synchronization may be large with respect
to the small amount of data. Hence, asynchronous operation is a
desired feature.
[0055] FIG. 2 illustrates a plot 200 of example transmissions made
by a plurality of MTDs. The transmissions made by the plurality of
MTDs, such as transmission 205 by MTD 1, transmission 210 by MTD 2,
and transmission 215 by MTD 3, in an asynchronous manner. Even if
there was intent to make the transmissions in a synchronous manner,
factors, such as propagation delay, clock drift, and the like, may
cause the transmissions to occur at different times. In order to
maintain synchrony, elaborate coordination techniques may need to
be employed. As an example, the MTDs may need to detect a periodic
synchronization broadcast made by the eNB to resynchronize their
clocks. The MTDs may also receive timing adjustment information
that may be used to adjust their clocks to help ensure that the
transmission arrive at the eNB in synchrony. However, detecting the
periodic synchronization broadcast (and potentially the timing
adjustment information) means that the MTDs must be awake to
receive the synchronization broadcast. Forcing the MTDs to
periodically wake up to detect the periodic synchronization
broadcast may significantly increase power consumption in the MTDs.
Since many MTDs are battery powered, increasing their power
consumption will dramatically reduce the battery life of the MTDs.
It is noted that an open-loop synchronization technique may be
implemented based on received downlink transmissions, such as
received beacons, to provide a measure of synchronization. However,
open-loop synchronization generally does not employ timing
adjustment information.
[0056] According to an example embodiment, in order to support the
sharing of available communications resources (e.g., time
resources, frequency resources, or time-frequency resources),
narrow band communications is used. In general, narrow band
communications uses channels (or frequency bands) that do not
exceed or significantly exceed the channels' coherence bandwidth (a
range of frequencies that the channel can be considered to be
flat). Transmissions from a single MTD occupies a single narrow
band channel that does not overlap with other narrow band channels.
Multiple access techniques, such as frequency division multiple
access (FDMA), code division multiple access (CDMA), time division
multiple access (TDMA), carrier sense multiple access (CSMA), CSMA
with collision detection (CSMA/CD), and the like, may be used to
allow more than one MTD to share communication resources and
increase the number of MTDs supported. Furthermore, a single
carrier is used. Offset Quadrature Amplitude Modulation (OQAM)
modulation may be used to modulate the information being
transmitted. Although the discussion focuses on the use of OQAM,
other modulation techniques, such as Quadrature Phase Shift Keying
(QPSK), MSK (minimum shift keying), Quadrature Amplitude Modulation
(QAM), and the like, may be used.
[0057] The use of single carrier modulation may offer a lower peak
to average power ratio (PAPR) and/or complexity than multicarrier
waveforms. Also, offset modulation, such as OQPSK, may be more
efficient for nonlinear power amplifiers due to the 90 degree phase
shift in OQPSK rather than the 180 degree phase shift for regular
QPSK. Therefore, hardware to support the MTC may be more energy
efficient, providing a low power and low cost implementation.
[0058] According to an example embodiment, a frequency localized
pulse shaping filter is used to minimize out-of-band emissions.
Minimizing the out-of-band emissions of the MTDs may allow for the
asynchronous transmissions by multiple MTDs without causing
interference to each other. An example of a frequency localized
pulse shaping filter is a root raise cosine filter, e.g., a RRC
pulse. Although the discussion focuses on the use of the RRC pulse
as the frequency localized pulse shaping filter, other filters may
be used, for example, the isotropic orthogonal transform algorithm
(IOTA) filter. Additionally, guard tones are used between
transmissions of MTDs to enable interference free asynchronous
transmission due to the low out-of-band emission of the pulses,
which ensures orthogonality of the waveforms from different MTDs by
separating them in the frequency domain. The guard tones may be
with respect to OFDM and/or OQAM.
[0059] According to an example embodiment, the signal waveform of
generalized frequency division multiplexing (GFDM) or single
carrier GFDM may be used in an MTC communications system. In such a
situation, GFDM may utilize frequency localized pulse shaping on
each sub-carrier. Therefore, GFDM may possess an advantage of low
out-of-band emission in comparison to OFDM. GFDM may also have a
reduced cyclic prefix (CP) when compared to GFDM. Furthermore,
single carrier GFDM (SC-GFDM), which is a version of GFDM with only
a single sub-carrier, has a very low peak-to-average power ratio
(PAPR). Hence, SC-GFDM may be a good candidate for use in an MTC
communications system.
[0060] According to an example embodiment, in order to achieve
extended or enhanced coverage for low signal plus interference to
noise ratio (SINR) MTDs, ultra narrow band transmissions with long
signaling pulses are used in place of repetition. Additionally,
transmission pulse bandwidth can be adjustable to meet MTD needs
and/or communications system condition. The adjustment of the
transmission bandwidth can enable energy consumption savings when
needed and/or possible.
[0061] Usually, in power limited situations, narrower bandwidths
may allow the MTD to concentrate the transmit power in a narrow
spectrum, thereby increasing the transmit power spectrum density.
In the time domain, the longer pulse means that energy per symbol
can be accumulated over a longer period of time, hence, increasing
the signal to noise ratio (SNR). The advantages of using narrow
bandwidth signals can be shown using a simple capacity formula. In
a power limited situation, the capacity C for a single MTD i may be
expressed as:
C.sub.i=W.sub.i log(1+SNR.sub.W.sub.i),
where W.sub.i is the bandwidth allocated to MTD i. Assuming that
the transmit power of the MTD is fixed at its maximum, then
SNR.sub.W.sub.i, is expressible as:
SNR W i = P t P L N 0 W i , ##EQU00001##
where P.sub.t is the transmit power, P.sub.L is the path-loss, and
N.sub.o is the noise power spectral density. It is noted that
SNR.sub.W.sub.i, is inversely proportional to the allocated
bandwidth.
[0062] When the SNR is low, the capacity is expressible as:
C i = W i log ( 1 + P t P L N 0 W i ) .apprxeq. P t P L N 0 .
##EQU00002##
Therefore, increasing the bandwidth of the channel does not gain
extra throughput. However, reducing the bandwidth allows more MTDs
to transmit due to more available channels. Therefore, for low SINR
MTDs, using narrow band channels is an effective technique to
improve coverage while allowing as many MTDs to communicate as
possible.
[0063] Furthermore, the use of long signaling pulses may allow for
increased resilience to synchronization errors. Even with open-loop
synchronization, performance degradation due to overlapping in time
between consecutive MTDs may be negligible.
[0064] FIG. 3 illustrates a flow diagram of example operations 300
occurring in an eNB as the eNB participates in MTC. Operations 300
may be indicative of operations occurring in an eNB, such as eNBs
105, 155, and 180, as the eNB participates in MTC with a MTD.
[0065] Operations 300 may begin with the eNB determining a
plurality of signal waveforms (block 305). The plurality of signal
waveforms may include single carrier waveforms, multicarrier
waveforms, single carrier narrow-band waveforms, single carrier
ultra narrow-band waveforms, and the like, with potentially
different bandwidths. Some types of waveforms may have multiple
different bandwidths, while other types may have a single
bandwidth. The particular configuration of the signal waveforms in
the plurality of signal waveforms may depend on implementation,
communications system capability, MCS levels supported, and the
like.
[0066] The eNB may receive communications requirements of a MTD
(block 307). As an example, the eNB may receive the communications
requirements of the MTD during an initial attachment procedure that
is performed with the MTD. As another example, the eNB may receive
the communications requirements of the MTD during a handover
procedure that is performed with the MTD. As yet another example,
the eNB may receive the communications requirements of the MTD when
the MTD updates and changes its communications requirements. As an
illustrative example, the communications requirements of the MTD
may include parameters specifying the communications requirements
of the MTD, such as a frequency or period of transmissions from the
MTD, an amount of information transmitted per transmission, a
bandwidth requirement of the MTD, a priority level of the MTD
and/or the communications, coverage requirement, a communications
system load, MTD geometry, MTD power consumption, and the like.
[0067] The eNB may assign a signal waveform out of the plurality of
signal waveforms to the MTD (block 309). The assignment of the
signal waveform may be in accordance with communications
requirements of the MTD. According to an example embodiment,
multiple signal waveforms may be assigned to the MTD. As an
illustrative example, if the MTD has different communications
requirements, more than one signal waveform may be assigned to the
MTD to meet the different communications requirements. The eNB may
determine transmission characteristics, e.g., the bandwidth and/or
a MCS level, for the MTD and transmit the transmission
characteristics to the MTD (block 311). The transmission
characteristics (e.g., bandwidth and/or the MCS level) may be
determined in accordance with signal waveform assigned to the MTD.
As an example, a MTD that has high bandwidth requirements may be
assigned a signal waveform with a wide bandwidth. Furthermore, the
eNB may assign the signal waveform with the MCS level set in
accordance with the allocated bandwidth. As an illustrative
example, if the MTD is a sensor that may transmit 1 kilo-bit of
data once every 10 seconds, the eNB may allocate a 100 kilo-hertz
wide channel to the MTD so that it can transmit its 1 kilo-bit of
data in about 0.01 seconds. Alternatively, the eNB may assign the
signal waveform in accordance with factors such as MTD type, MTD
priority, communications system load, and the like. As an
illustrative example, the eNB may have the plurality of signal
waveforms with each preselected for different MTD types (or MTD
priority, channel quality, data load, and the like). The eNB may
simply select a signal waveform of the plurality of signal
waveforms in accordance with the MTD type (or MTD priority, channel
quality, data load, and the like) and total communication system
load and transmit an indicator of the signal waveform to the
MTD.
[0068] The eNB may allocate a communications resource(s) to the MTD
in accordance with the communications requirements (block 313). As
an illustrative example, the eNB may allocate time-frequency
resources commensurate with the communications requirements of the
MTD and/or the communications characteristics for the MTD. The eNB
may also consider the communications requirements of other MTDs
served by the eNB, as well as other factors, such as communications
system load, communications system condition, and the like, as it
allocates communications resources. The allocation of the resources
may be a persistent or semi-persistent allocation to meet the
on-going communications requirements of the MTD. As an illustrative
example, the eNB may allocate the time-frequency resources in a
periodic manner based on the frequency or period of the
transmissions as specified by the MTD. FIG. 4 illustrates a diagram
of example communications resources 400 in a 3GPP LTE
communications system. Communications resources 400 may include
resources for uplink transmissions and downlink transmissions. Some
of the communications resources may be allocated for MTC, while a
remainder of the communications resources is allocated for 3GPP LTE
communications. The eNB may allocate one or more of the network
resources to the MTD.
[0069] Referring back now to FIG. 3, the eNB may transmit resource
allocation information to the MTD (block 315). The resource
allocation information may specify where and when the allocated
communications resource(s) can be found by the MTD. As an
illustrative example, the resource allocation information may
include a time, a frequency, a frame number, and the like, so that
the MTD knows where and when to transmit. The resource allocation
information may be transmitted to the MTD during the attachment
procedure, the handover procedure, broadcast to the MTD, and the
like. The eNB may receive a transmission from the MTD in accordance
with the resource allocation information (block 317). The
transmission may be transmitted using the signal waveform.
[0070] FIG. 5 illustrates a flow diagram of example operations 500
occurring in a MTD as the MTD participates in MTC. Operations 500
may be indicative of operations occurring in a MTD, such as MTDs
114, 116, 160, 162, 164, 185, and 187, as the MTD participates in
MTC.
[0071] Operations 500 may begin with the MTD receiving transmission
characteristics from an eNB (block 502). The transmission
characteristics, e.g., bandwidth allocation and/or MCS, may inform
the MTD about the signal waveform to be used by MTD, as well as a
MCS level to be used for the transmission. The transmission
characteristics may be received during an initial attachment
procedure, a handover procedure, and the like. Alternatively, the
transmission characteristics may be received after the eNB adjusts
the bandwidth and/or MCS level of the signal waveform to meet
changing communications system load. According to an example
embodiment, the MTD may receive information about multiple signal
waveforms if multiple signal waveforms were assigned to the
MTD.
[0072] The MTD may receive resource allocation information from the
eNB (block 505). The resource allocation information may specify
where and when the allocated communications resource(s) can be
found by the MTD. As an illustrative example, the resource
allocation information may include a time, a frequency, a frame
number, and the like, so that the MTD knows where and when to
transmit. The resource allocation information may have been
generated by the eNB in response to communications requirements of
the MTD, which may have been provided by the MTD. Alternatively,
the communications requirements of the MTD may one of several
default communications requirements associated with MTD type,
priority, and the like.
[0073] The MTD may receive the resource allocation information
during the attachment procedure, the handover procedure, in a
broadcast or transmission to the MTD, and the like. The MTD may
perform a check to determine if it has data (information) to
transmit (block 510). If the MTD has data to transmit, the MTD may
generate a packet(s) including the data (block 515). The generation
of the packet(s) may include placing the data into a payload of the
packet(s), adding header(s) and/or footer(s) along with control
information, encoding to provide error detection and/or correction,
and the like. The MTD may transmit the generated packet in
accordance with the resource allocation information (block 520).
Transmitting the generated packet may include operations such as
digital to analog conversion, filtering with a frequency localized
pulse shaping filter, such as a RRC pulse, modulation using OQAM,
signal amplification, and the like. The transmission of the
packet(s) may make use of the signal waveform.
[0074] According to an example embodiment, the bandwidth allocated
to a MTD may be varied (adjusted) to meet communications
requirements of the MTD and/or communications system conditions. As
discussed previously, if maximizing the number of MTDs supported is
a goal, when the MTDs are limited in power, a narrow bandwidth is
typically advantageous as it boosts total transmit power or power
spectrum density, thereby allowing the support of more MTDs.
However, the use of narrow bandwidths for all MTDs restricts
performance for MTDs that are not power limited or MTDs that have
good channel conditions (i.e., good channel SINR). Additionally,
power consumption in a MTD typically increases as the MTD takes
longer to transmit when using a narrow bandwidth channel when
compared to a wide bandwidth channel is used. Furthermore, in a
communications system that uses a fixed size guard band, the fixed
size guard band consumes greater overhead when used in conjunction
with a narrow bandwidth channel (especially when the guard band is
wider than the narrow bandwidth channel) then when used with a wide
bandwidth channel. Also, limitations on throughput (the bandwidth
of the channel) may prevent the support of diverse MTDs that
require different data rates. In addition, energy consumption is
usually important in MTC applications since many sensors are
battery powered and battery life is an important consideration in
designing MTD systems.
[0075] When the communications system is underloaded, signal
waveforms with larger bandwidths may be assigned to MTDs to improve
energy efficiency, while when the communications system is
overloaded, signal waveforms with narrow bandwidths may be used to
support as many MTDs as possible. Hence, a bandwidth adjusting
technique may consider both long term channel characteristics of
MTDs, such as SINR, as well as the load of the communications
system. In addition, energy efficiency of remote MTDs may be more
important than energy efficiency of close MTDs since they may be
more likely to run out of battery due to increased transmission
time for the same data load. FIG. 6 illustrates a diagram of a
communications system 600 that supports adjustable bandwidth for
MTDs. Communications system 600 includes an eNB 605 communicating
with a plurality of MTDs. Distance between eNB 605 and the MTDs
differ, therefore, the channel condition for the MTDs may also
differ. As an illustrative example, MTD 610 is very close to eNB
605 and has a high SINR channel, MTD 612 is relatively close to eNB
605 and has a medium SINR channel, while MTD 614 is far from eNB
605 and has a low SINR channel.
[0076] As discussed previously, eNB 605 may be able to adjust the
bandwidths used for MTC in accordance with the channel condition of
the MTDs as well as the load of communications system 600. For
illustrative purposes, consider a situation where communications
system 600 is lightly loaded and permits the adjustment of
bandwidths. Then, MTD 610 with a high SINR channel can have its
bandwidth increased significantly (as shown in pulse 611), and MTD
612 with a medium SINR channel can have its bandwidth increased
(shown as pulse 613) but not to the extent of pulse 611. However,
MTD 614 with a low SINR channel cannot have its bandwidth increased
(shown as pulse 615). MTD 614 may need to rely upon a signal
waveform with a narrow bandwidth and long pulse signaling to obtain
extended coverage from eNB 605.
[0077] FIG. 7 illustrates a flow diagram of example operations 700
occurring in an eNB as the eNB adjusts the transmission
characteristics of MTDs. Operations 700 may be indicative of
operations occurring in an eNB, such as eNBs 105, 155, and 180, as
the eNB adjusts the transmission characteristics of channels of
MTDs.
[0078] Operations 700 may begin with the initialization of the
communications system (block 705). According to an example
embodiment, the initialization may include a definition of possible
transmission characteristics, e.g., possible modulation and coding
scheme (MCS) levels, as well as bandwidth choices. The
initialization may be met by defining a plurality of signal
waveforms with a variety of MCS levels and bandwidth choices. As an
illustrative example, a minimum MCS level may be OQPSK modulation
with a code rate of 1/3, while a highest MCS level may be dependent
on the importance of energy efficiency, an example of which may be
16-QAM with a code rate of 3/4. Similarly, a minimum bandwidth may
be set with consideration being given to radio-frequency limits of
frequency offset. The number of MCS levels and/or bandwidth choices
may be determined as a trade-off between overhead (e.g., signaling
overhead required to signal changes, signaling overhead required to
report channel condition, computational overhead required to adjust
the bandwidth, the computational overhead required to determine
load condition of the communications system, and the like) and
performance.
[0079] The eNB may perform a check to determine if the
communications system is overloaded (block 710). If the
communications system, in particular, the eNB and possibly some of
its neighbor eNBs, are not overloaded, the eNB may increase the
bandwidth for at least some of its MTDs (block 715). In general,
the eNB may increase the bandwidth by selecting a signal waveform
with the desired bandwidth and/or MCS level. In an underloaded
situation, it may be important for MTDs to have high energy
efficiency while saving battery power. The eNB may allocate maximum
supported bandwidth at the lowest MCS level without repetition to
the MTDs. Higher MCS levels may be used if the MTD can support that
MCS levels with maximum bandwidth. The eNB may reduce MCS level if
needed while increasing the bandwidth. The eNB may examine all of
its MTDs, starting with a MTD with the lowest throughput, for
example, and increase the bandwidth for the MTDs that can benefit
from the bandwidth increase. As an example, if the MTD with the
lowest throughput has a very low SINR, then the MTD may not be a
good candidate for a bandwidth increase. However, a MTD with a
medium or better SINR may be a good candidate for a bandwidth
increase. According to an example embodiment, the increase in
bandwidth for a MTD is selected in accordance with performance
factors. Examples of performance factors include data transmission
requirements of the MTD (if the MTD has very low data transmission
requirements, it may not be advantageous to increase the bandwidth
of the MTD, for example), the channel condition of the MTD,
available capacity of the communications system, the number of MTDs
suitable for bandwidth increase, and the like.
[0080] If the eNB made changes to the bandwidth (and/or MCS level)
of any of its MTDs, the eNB may inform the MTD(s) of the change
(block 720). The eNB may broadcast information regarding the
changes or it may individually transmit the information to the
affected MTDs.
[0081] If the communications system, in particular, the eNB and
possibly some of its neighbor eNBs, are overloaded, the eNB may
increase the MCS level for at least some of its MTDs (block 725).
In general, the eNB may increase the MCS level by selecting a
signal waveform with the desired MCS level and/or bandwidth. In an
overloaded situation, the eNB may maximize the number of MTDs.
Therefore, spectral efficiency may be more important and the eNB
may use the minimum bandwidth and only increase the bandwidth if
the MTDs can support higher MCS levels with greater signal pulse
bandwidth. The eNB may reduce the bandwidth if needed while
increasing the MCS level. The eNB may examine all of its MTDs,
starting with a MTD with the highest throughput, for example, and
increase the MCS level for the MTDs that can benefit from the MCS
increase. If the eNB made changes to the MCS level (and/or
bandwidth) of any of its MTDs, the eNB may inform the MTD(s) of the
change (block 720). The eNB may broadcast information regarding the
changes or it may individually transmit the information to the
affected MTDs.
[0082] It is noted that in a medium load situation, where the
communications system is neither overloaded nor underloaded, the
selection of bandwidth and/or MCS level may push the communications
system into either overload or underload. In such a situation, the
eNBs may set the MTDs assuming that the communications system is in
an underloaded condition to help preserved the batter power of the
MTDs. The eNB may then gradually increase the MCS level of the MTDs
while reducing bandwidth (if needed) to support the higher MCS
level. A decision to be made in the medium load situation is which
MTD's MCS level should be increased first. In other words, how to
ensure fairness for the MTDs. As an example, the MTDs that are
farther away from the eNB may be prioritized since their batteries
tend to deplete faster due to operation under low bandwidth
conditions. In such a situation, MTD throughput may be used as a
deciding factor. As an illustrative example, a MTD having the
highest throughput may be selected and its MCS level may be
increased and bandwidth may be decreased (if necessary).
[0083] FIG. 8 illustrates an example first communications device
800. Communications device 800 may be an implementation of a
communications controller, such as an eNB, a base station, a NodeB,
a controller, and the like. Communications device 800 may be used
to implement various ones of the embodiments discussed herein. As
shown in FIG. 8, a transmitter 805 is configured to transmit
packets, resource allocation information, and the like.
Communications device 800 also includes a receiver 810 that is
configured to receive packets, communications requirements, and the
like.
[0084] A requirement processing unit 820 is configured to process
communications requirements from a MTD. The communications
requirements may specify parameters, such as coverage requirement,
a communications system load, MTD geometry, MTD power consumption,
frequency or period of transmissions from the MTD, an amount of
information transmitted per transmission, a priority level of the
communications, and the like. An assigning unit 822 is configured
assign a signal waveform to a MTD in accordance with communications
requirements of the MTD. Assigning unit 822 is configured to select
the signal waveform from a plurality of signal waveforms. A
resource allocation unit 824 is configured to allocate
communications resources for the MTD in accordance with the
communications requirements. Resource allocation unit 824 is
configured to consider communications requirements from MTDs served
by communications device 800, condition of a communications system
that includes communications device 800, and the like. An adjusting
unit 826 is configured to adjust transmission parameters, e.g.,
bandwidth and/or MCS level, of MTD. Adjusting unit 826 is
configured to consider communications system load, as well as
channel condition (e.g., SINR, SNR, and the like), as it adjusts
the bandwidth and/or MCS level. Adjusting unit 826 is configured to
generate signaling to inform MTDs regarding any adjustments in
their bandwidth and/or MCS level. A memory 830 is configured to
store transmission parameters, communications requirements,
resource allocations, resource allocation information, channel
parameters, bandwidth assignments, MCS level assignments, channel
condition, communications system load, and the like.
[0085] The elements of communications device 800 may be implemented
as specific hardware logic blocks. In an alternative, the elements
of communications device 800 may be implemented as software
executing in a processor, controller, application specific
integrated circuit, or so on. In yet another alternative, the
elements of communications device 800 may be implemented as a
combination of software and/or hardware.
[0086] As an example, receiver 810 and transmitter 805 may be
implemented as a specific hardware block, while requirement
processing unit 820, assigning unit 822, resource allocation unit
824, and adjusting unit 826 may be software modules executing in a
microprocessor (such as processor 815) or a custom circuit or a
custom compiled logic array of a field programmable logic array.
Requirement processing unit 820, assigning unit 822, resource
allocation unit 824, and adjusting unit 826 may be modules stored
in memory 830.
[0087] FIG. 9 illustrates an example second communications device
900. Communications device 900 may be an implementation of a MTD,
and the like. Communications device 900 may be used to implement
various ones of the embodiments discussed herein. As shown in FIG.
9, a transmitter 905 is configured to transmit packets,
communications requirements, and the like. Communications device
900 also includes a receiver 910 that is configured to receive
packets, resource allocation information, and the like.
[0088] A requirement processing unit 920 is configured to generate
communications requirements for communications device 900. The
communications requirements may specify parameters, such as
frequency or period of transmissions from the MTD, an amount of
information transmitted per transmission, a priority level of the
communications, and the like. Requirement processing unit 920 is
configured to generate messaging for transmitting the
communications requirements. An allocation processing unit 922 is
configured to process resource allocation information received by
communications device 900 to determine transmission opportunities
for communications device 900. Allocation processing unit 922 is
configured to process transmission characteristics of a signal
waveform. A packet processing unit 924 is configured to process
packets received by communications device 900. Packet processing
unit 924 is configured to process packets containing bandwidth
and/or MCS level adjustments. A memory 930 is configured to store
communications requirements, resource allocations, resource
allocation information, bandwidth assignments, MCS level
assignments, channel condition, communications system load, channel
parameters, and the like.
[0089] The elements of communications device 900 may be implemented
as specific hardware logic blocks. In an alternative, the elements
of communications device 900 may be implemented as software
executing in a processor, controller, application specific
integrated circuit, or so on. In yet another alternative, the
elements of communications device 900 may be implemented as a
combination of software and/or hardware.
[0090] As an example, receiver 910 and transmitter 905 may be
implemented as a specific hardware block, while requirement
processing unit 920, allocation processing unit 922, and packet
processing unit 924 may be software modules executing in a
microprocessor (such as processor 915) or a custom circuit or a
custom compiled logic array of a field programmable logic array.
Requirement processing unit 920, allocation processing unit 922,
and packet processing unit 924 may be modules stored in memory
930.
[0091] In accordance with an example embodiment of the present
disclosure, a method for operating a communications controller is
provided. The method includes determining, by the communications
controller, communications requirements for a machine-type device
(MTD), and assigning, by the communications controller, a first
signal waveform selected from a plurality of signal waveforms to
the MTD in accordance with the determined communications
requirements, wherein each signal waveform has an associated
characteristic signal bandwidth. The method also includes
transmitting, by the communications controller, information about
the first signal waveform to the MTD.
[0092] In accordance with another example embodiment of the present
disclosure, a method for operating a machine-type device (MTD) is
provided. The method includes receiving, by the MTD, transmission
characteristics of a signal waveform from a communications
controller, wherein the signal waveform has an associated
characteristic signal bandwidth, and wherein the transmission
characteristics include at least one of a bandwidth associated with
the MTD, and a level of a modulation and coding scheme (MCS) used
for transmission, and generating, by the MTD, a packet including
data to be transmitted. The method also includes transmitting, by
the MTD, the packet to the communications controller in accordance
with the transmission characteristics, wherein the packet is
transmitted using the signal waveform.
[0093] In accordance with an example embodiment of the present
disclosure, a communications controller is provided. The
communications controller includes a processor, and a transmitter
operatively coupled to the processor. The processor determines
communications requirements for a machine-type device (MTD), and
assigns a first signal waveform out of a plurality of signal
waveforms to the MTD in accordance with the communications
requirements for the MTD, wherein each signal waveform has an
associated characteristic signal bandwidth. The transmitter
transmits information about the first signal waveform to the
MTD.
[0094] In accordance with an example embodiment of the present
disclosure, a machine-type device (MTD) is provided. The MTD
includes a receiver, a processor operatively coupled to the
receiver, and a transmitter operatively coupled to the processor.
The receiver receives transmission characteristics of a signal
waveform from a communications controller, wherein the signal
waveform has an associated characteristic signal bandwidth, and
wherein the transmission characteristics include at least one of a
bandwidth associated with the MTD, and a level of a modulation and
coding scheme (MCS) used for transmission. The processor generates
a packet including data to be transmitted. The transmitter
transmits the packet to the communications controller in accordance
with the transmission characteristics, wherein the packet is
transmitted using the signal waveform.
[0095] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the disclosure as defined by the
appended claims.
* * * * *