U.S. patent application number 16/571968 was filed with the patent office on 2020-01-09 for systems and methods of adaptive mitigation for shared access.
The applicant listed for this patent is CABLE TELEVISION LABORATORIES, INC.. Invention is credited to ROBERT ALDERFER, BERNARD McKIBBEN, GREGORY RUTZ.
Application Number | 20200015092 16/571968 |
Document ID | / |
Family ID | 59066966 |
Filed Date | 2020-01-09 |
United States Patent
Application |
20200015092 |
Kind Code |
A1 |
ALDERFER; ROBERT ; et
al. |
January 9, 2020 |
SYSTEMS AND METHODS OF ADAPTIVE MITIGATION FOR SHARED ACCESS
Abstract
A method for managing shared wireless communications in a
wireless communication network is provided. The wireless
communications network includes at least one cooperative device and
at least one non-cooperative device. The method includes the steps
of monitoring, by the at least one cooperative device, a selected
channel of a shared spectrum of the wireless communication network,
detecting, by the at least one cooperative device, a presence of a
transmission from the non-cooperative device within a measurable
vicinity of the cooperative device, and responding, by the at least
one cooperative device, to the detected presence of the
transmission from the non-cooperative device.
Inventors: |
ALDERFER; ROBERT;
(Louisville, CO) ; McKIBBEN; BERNARD; (Broomfield,
CO) ; RUTZ; GREGORY; (Arvada, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CABLE TELEVISION LABORATORIES, INC. |
Louisville |
CO |
US |
|
|
Family ID: |
59066966 |
Appl. No.: |
16/571968 |
Filed: |
September 16, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15387299 |
Dec 21, 2016 |
10419940 |
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16571968 |
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62270427 |
Dec 21, 2015 |
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62302912 |
Mar 3, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/241 20130101;
H04W 4/80 20180201; H04W 52/243 20130101; H04W 16/14 20130101; H04W
74/0816 20130101 |
International
Class: |
H04W 16/14 20060101
H04W016/14; H04W 52/24 20060101 H04W052/24; H04W 74/08 20060101
H04W074/08; H04W 4/80 20060101 H04W004/80 |
Claims
1. A method for managing shared wireless communications in a
wireless communication network including at least one cooperative
device and at least one non-cooperative device, the method
comprising the steps of: monitoring, by the at least one
cooperative device, a selected channel of a shared spectrum of the
wireless communication network; detecting, by the at least one
cooperative device, a presence of a transmission from the
non-cooperative device within a measurable vicinity of the
cooperative device; and responding, by the at least one cooperative
device, to the detected presence of the transmission from the
non-cooperative device.
2. The method of claim 1, wherein the at least one cooperative
device utilizes a distributed access protocol relating to one or
more of Wi-Fi, Bluetooth, and Zigbee technologies.
3. The method of claim 1, wherein the at least one non-cooperative
device utilizes one or more of a long term evolution protocol and
an unlicensed long term evolution protocol.
4. The method of claim 1, wherein the step of detecting comprises a
substep of employing carrier sense multiple access with collision
avoidance.
5. The method of claim 1, wherein the step of detecting comprises a
substep of identifying operational information of the transmission
from the non-cooperative device.
6. The method of claim 5, wherein the substep of identifying
determines that the transmission from the non-cooperative device is
an aggressive transmission.
7. The method of claim 6, wherein the step of responding comprises
one or more of the substeps of reporting the detected presence of
the aggressive transmission, calculating operational parameters of
the aggressive signal, and adapting a polite transmission of the at
least one cooperative device based on the identified operational
information of the aggressive transmission.
8. The method of claim 7, wherein the substep of adapting further
comprises one or more of the additional substeps of maintaining a
legacy protocol of the polite transmission, avoiding a frequency
domain of the aggressive transmission, scheduling the polite
transmission to transmit within periods when a duty cycle of the
aggressive transmission is off, increasing an output power of the
polite transmission, adjusting a throughput of the polite
transmission, and transmit redundant data relating to the polite
transmission.
9. The method of claim 8, wherein, when implementing the substep of
maintaining, the substep of calculating first determines that
performance loss of the polite transmission, in the presence of the
aggressive transmission, is unlikely.
10. The method of claim 8, wherein, when implementing the substep
of scheduling, the substep of calculating first calculates the duty
cycle of the aggressive transmission from the operational
parameters.
11. The method of claim 10, wherein the substep of scheduling
comprises the further substep of synchronizing a contention window
of the polite transmission to conform with an off state of the duty
cycle of the aggressive transmission.
12. The method of claim 8, wherein the substep of avoiding
comprises the further substep of switching a transmission channel
of the polite transmission to a different transmission channel that
does not contain the aggressive transmission.
13. The method of claim 8, wherein the substep of increasing the
output power comprises the further substep generating a sufficient
signal to noise ratio for the polite transmission to overcome an
increased noise level in the selected channel resulting from the
presence of the aggressive transmission.
14. The method of claim 8, wherein the substep of adjusting the
throughput comprises the further substep reducing the transmission
speed of the polite transmission.
15. A wireless communications system, comprising: at least one
cooperative electronic device including a processor and a
transceiver; at least one non-cooperative electronic device; an
access point configured to wirelessly send and receive polite
transmission data to and from the at least one cooperative
electronic device, respectively; and a communications node
configured to wirelessly send and receive aggressive transmission
data to and from the at least one non-cooperative electronic
device, respectively, wherein the transceiver is configured to
monitor a selected channel of a shared spectrum of the wireless
communications system and identify the presence of the aggressive
transmission data within a proximity of the at least one
cooperative electronic device.
16. The system of claim 15, wherein the at least one cooperative
device comprises a Wi-Fi device.
17. The system of claim 15, wherein the at least one
non-cooperative device comprises an unlicensed long term evolution
user equipment.
18. The system of claim 15, wherein the communications node
comprises evolved Node B hardware.
19. The system of claim 15, wherein the processor is configured to
cause the transceiver to respond to the identified presence of the
aggressive transmission data.
20. The system of claim 19, wherein the transceiver is further
configured to initiate a response comprising one or more of
reporting the identified presence of the aggressive transmission
data, calculating operational parameters of the aggressive
transmission data, and adapting the polite transmission data based
on identified operational information of the aggressive
transmission data.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Nonprovisional
patent application Ser. No. 15/387,299, filed Dec. 21, 2016, which
application claims the benefit of and priority to U.S. Provisional
Patent Application Ser. No. 62/270,427, filed Dec. 21, 2015, and to
U.S. Provisional Patent Application Ser. No. 62/302,912, filed Mar.
3, 2016, all of which are incorporated herein by reference in their
entirety.
BACKGROUND
[0002] The field of the disclosure relates generally to management
of shared wireless communications, and more particularly, to
wireless communication management utilizing adaptive
mitigation.
[0003] Conventional wireless communication systems utilize a shared
spectrum. For example, the 2.4 GHz and 5 GHz frequency bands are
used for Wi-Fi, Bluetooth, Zigbee, and a range of other consumer,
industrial, and medical wireless technologies. Other technology
platforms also share a spectrum in other frequency ranges, and
available wireless spectra will become more intensively shared as
demand for wireless technologies increases.
[0004] Some conventional shared spectrum technology systems utilize
algorithm- and sensing-based distributed access, which enable
common use of a wireless resource, despite a lack of active
coordination among users. For example, typical Wi-Fi systems employ
a carrier sense multiple access with collision avoidance (CSMA/CA)
network multiple access method, which is also known as
"listen-before-talk" (LBT), in which carrier sensing is used, but
nodes attempt to avoid collisions by transmitting only when the
channel is sensed to be idle (not being used). Wi-Fi devices employ
a common, standards-based protocol to avoid interference among
themselves and other users, which provides a substantially equal
probability of access across all users in channel conditions.
[0005] However, new technologies are being introduced into the
shared spectrum, which do not employ the cooperative techniques
used by Wi-Fi devices. In particular, the introduction of mobile
technologies utilizing Long Term Evolution (LTE) are known to
interfere with existing technologies like Wi-Fi, due to the
centralized architecture of LTE and mobile systems where spectrum
access is scheduled by the network, instead of being distributed by
a common protocol of the device accessing the network. Mobile
technologies utilizing LTE are able to thus dominate access to a
shared spectrum without regard to cooperative technologies. These
non-cooperative mobile technologies can be implemented in an
aggressive manner that utilizes a disproportionate share of
airtime, as compared with cooperative technologies. For example,
when a scheduled technology, such as LTE, competes with a
technology that employs distributed coordination techniques, such
as Wi-Fi, the Wi-Fi system will inherently defer to (that is, fail
to transmit) the scheduled technology. In other words, the Wi-Fi
system (and similar cooperative technologies) will "hear" the LTE
system (or non-cooperative technologies) "talking," and will wait
their turn to access and transmit to the network. Wi-Fi and other
cooperative/distributed technologies are thus at an inherent
disadvantage in the shared spectrum, and will experience
significant interference and degraded performance when forced to
compete with non-cooperative technologies.
BRIEF SUMMARY
[0006] In an embodiment, a method for managing shared wireless
communications in a wireless communication network is provided. The
wireless communications network includes at least one cooperative
device and at least one non-cooperative device. The method includes
the steps of monitoring, by the at least one cooperative device, a
selected channel of a shared spectrum of the wireless communication
network, detecting, by the at least one cooperative device, a
presence of a transmission from the non-cooperative device within a
measurable vicinity of the cooperative device, and responding, by
the at least one cooperative device, to the detected presence of
the transmission from the non-cooperative device.
[0007] In an embodiment, a wireless communications system includes
at least one cooperative electronic device having a processor and a
transceiver, at least one non-cooperative electronic device, an
access point configured to wirelessly send and receive polite
transmission data to and from the at least one cooperative
electronic device, respectively, and a communications node
configured to wirelessly send and receive aggressive transmission
data to and from the at least one non-cooperative electronic
device, respectively. The transceiver is configured to monitor a
selected channel of a shared spectrum of the wireless
communications system and identify the presence of the aggressive
transmission data within a proximity of the at least one
cooperative electronic device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0009] FIG. 1 is a schematic illustration of a shared spectrum
system, according to an embodiment.
[0010] FIG. 2 illustrates an effect of an exemplary duty cycle of a
periodic scheduled waveform on transmission parameters for the
embodiment depicted in FIG. 1.
[0011] FIG. 3 is a graphical representation of a cooperative
technology signal, according to an embodiment.
[0012] FIG. 4 is a graphical representation illustrating the
scheduling of the cooperative technology signal depicted in FIG. 3,
in the presence of the non-cooperative technology signal depicted
in FIG. 1.
[0013] Unless otherwise indicated, the drawings provided herein are
meant to illustrate features of embodiments of this disclosure.
These features are believed to be applicable in a wide variety of
systems including one or more embodiments of this disclosure. As
such, the drawings are not meant to include all conventional
features known by those of ordinary skill in the art to be required
for the practice of the embodiments disclosed herein.
DETAILED DESCRIPTION
[0014] In the following specification and claims, reference will be
made to a number of terms, which shall be defined to have the
following meanings.
[0015] The singular forms "a," "an," and "the" include plural
references unless the context clearly dictates otherwise.
[0016] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0017] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about,"
"approximately," and "substantially," are not to be limited to the
precise value specified. In at least some instances, the
approximating language may correspond to the precision of an
instrument for measuring the value. Here and throughout the
specification and claims, range limitations may be combined and/or
interchanged; such ranges are identified and include all the
sub-ranges contained therein unless context or language indicates
otherwise.
[0018] The embodiments herein describe and illustrate a transceiver
and methods for adaptive management of shared wireless
communications, and particularly wireless communications in the
unlicensed spectrum, or unlicensed bands (e.g., 2.4 GHz, 3.5 GHz, 5
GHz, etc.). Examples of technologies used in the unlicensed
spectrum include Wi-Fi, Bluetooth, Zigbee, with Wi-Fi presently
being the dominant technology for unlicensed shared access. Wi-Fi
is a cooperative technology that uses CSMA/CA to ensure the
efficacy of distributed access across otherwise uncoordinated
transceivers. Such cooperative technology includes coexistence
features that allow it to first verify (e.g., by LBT), before
accessing a channel, that the channel is clear prior to
transmission of data. CSMA/CA then allows for the distribution of
access control to all cooperative users (i.e., user devices) on
that channel.
[0019] Technologies such as LTE operate in the unlicensed spectrum
(e.g., LTE-U) in a non-cooperative manner. LTE-U has been widely
deployed, and functions to dominate the unlicensed spectrum through
a centralized control of aggressive transmission techniques. The
cooperative technologies are colloquially referred to as "polite"
technologies, whereas the non-cooperative technologies are
colloquially referred to as "aggressive" technologies. LTE-U is
considered aggressive, since it schedules and applies traffic to
the accessed channel without first assessing if the channel is
clear of other network transmissions. LTE-U may sometimes implement
separate systems to avoid the LTE-U transmissions, but LTE-U will
typically transmit over other technologies without such separate
systems.
[0020] LTE-U generally operates according to an ON/OFF duty cycle.
The embodiments disclosed herein feature systems and methods for
alternative access models in a shared spectrum channel when LTE-U
is "ON," as compared to when the LTE-U is "OFF." The present
transceiver systems and methods are configured to adapt their use
of the shared spectrum to enable more robust access in the presence
of non-cooperative technologies and interfering signals. These
advantageous features thus enable an improved continuing utility of
Wi-Fi and other cooperative technologies in an environment of
technological convergence on a shared spectrum.
[0021] In an exemplary embodiment, existing polite technologies in
the unlicensed band are configured to mitigate the transmission
from aggressive technologies that are not designed for distributed
control of the accessed channel. Such mitigation techniques further
configured to operate in their normal manner when in the presence
of other polite protocols, but adapt their operation in the
presence of aggressive protocols. For simplicity of explanation,
many of the following examples are described only with respect to
Wi-Fi as the polite protocol and LTE-U as the aggressive protocol.
Nevertheless, the systems and methods described herein may also be
utilized similarly with respect to other polite and aggressive
technologies, respectively.
[0022] According to an embodiment, a cooperative technology, such
as Wi-Fi, is configured to monitor and/or sense the spectrum for
which access is desired, and detect the waveforms (also known as
"signatures") of non-cooperative technologies, such as LTE. In this
example, when a non-cooperative technology is not detected, the
cooperative technology can be configured to remain in its legacy
state of distributed access protocols. That is, the cooperative
technology will respond to the additional monitoring/detection
functions without changing other operations, such as the LBT
protocol, for example. However, when a non-cooperative technology
is detected, the transceiver utilizing the cooperative technology
is configured to utilize a number of functional techniques to adapt
and maintain its performance. Such techniques may include, without
limitation: (a) "do nothing"; (b) avoidance; (c) scheduling; (d)
power adjustment; (e) throughput adjustment; and (f) reliability
restoration.
[0023] When implementing the "do nothing" technique, the
transceiver (or cooperative node) is configured to assess whether
the non-cooperative node is deemed to not be of an aggressive
nature, and then determine that no performance diminution of the
transceiver/cooperative node is necessary or likely for continued
operation. When implementing the avoidance technique, the
transceiver or cooperative node is configured to assess the
availability of other channels, and then switch transmission to an
alternative channel in order to avoid the non-cooperative node in
the frequency domain. When implementing the scheduling technique,
the transceiver or cooperative node is configured to assess the
duty cycle (ON/OFF periods) of the non-cooperative signal/node and
adapts its own transmission in the time domain using a predictive
model. (See FIG. 4, below).
[0024] For the power adjustment technique, the transceiver or
cooperative node is configured to assess the signal-to-noise ratio
of its own cooperative system in the presence of a non-cooperative
node, and then adapt its own transmission power in order to improve
signal quality (subject to regulatory restrictions on power
levels). For the throughput adjustment technique, the transceiver
or cooperative node is configured to reduce its own transmission
speed in order to maintain reliability. For the reliability
restoration technique, the transceiver or cooperative node is
configured to assess transmission errors and airtime collisions and
adapt its own data transmission to improve transmission
quality.
[0025] In the exemplary embodiment, each of the foregoing
adaptation techniques may be implemented alone, or in combination
with one or more of the other techniques. In some embodiments, the
several techniques may be implemented simultaneously, or in
succession. In this example, the transceiver/node utilizing the
cooperative technology is configured to the channel of the shared
spectrum and adapt its medium access cooperative protocol using one
or more of the techniques described above in order to maintain its
performance in the presence of non-cooperative technologies in the
same shared spectrum. These advantageous adaptation techniques are
described further below with respect to several drawings.
[0026] FIG. 1 is a schematic illustration of an exemplary shared
spectrum system 100, according to an embodiment. System 100
includes at least one user equipment (UE) 102, a Wi-Fi device 104,
a node 106, and an access point (AP) 110. User equipment 102 may
be, for example, a mobile handset, or similar device, that
implements an LTE-U transmission protocol to establish an LTE
transmission 110 with node 106. In the exemplary embodiment, node
106 may be, for example, an E-UTRAN Node B, also known as Evolved
Node B, (abbreviated as eNodeB or eNB) as a hardware element that
is communicatively coupled with a mobile phone network (not shown)
that communicates wirelessly with user equipment 102. In some
embodiments, node 106 may further include a base transceiver
station (BTS) for a Global System for Mobile communication (GSM)
network. In the exemplary embodiment, Wi-Fi device 104 includes a
transceiver or cooperative node (not shown) which establishes a
Wi-Fi transmission 112 with access point 110. In an embodiment, the
cooperative node of Wi-Fi device 104 includes the transceiver.
[0027] In operation, user equipment 102 generates an aggressive
transmission signal 114 according to a duty cycle (symbolically
represented by dashed lines) within the range of Wi-Fi device 104,
which creates an interference 116 in Wi-Fi transmission 112. In the
exemplary embodiment, Wi-Fi transmission 112 implements a polite
LBT protocol that will typically give way to the detected presence
of aggressive transmission signal 114. That is, a cooperative
shared spectrum technology, such as Wi-Fi, has the ability to
"listen" to the channel of the unlicensed shared spectrum to
determine the presence of other users. This listening ability is
conventionally employed only for the specific purpose outlined in
distributed access protocols for coexistence with other cooperative
technologies.
[0028] According to the exemplary embodiment, Wi-Fi device 104 is
further configured to utilize its existing listening capability to
monitor system 100, and then detect and identify the presence of
aggressive transmission signal 114. Once aggressive transmission
signal 114 is detected/identified, Wi-Fi device 104 is additionally
configured to implement one or more of the adaptive behavior
techniques described above. In the exemplary embodiment, signatures
of non-cooperative technologies, such as LTE, are detected by the
transceiver/cooperative node of Wi-Fi device 104 using information
gathered through this additional listening process. In some
embodiments, this additional listening process may further utilize
information relating to the performance of system 100 or Wi-Fi
device 104.
[0029] In an operative example, the non-cooperative LTE-U
technology of user equipment 102 schedules aggressive transmission
signal 114 through a duty-cycled ON/OFF mechanism (not shown) of
the device. Over a period of time, these duty cycles can be
detected by Wi-Fi device 104 and correctly identified as a
non-cooperative technology. As described below with respect to FIG.
4, the detected LTE-U waveform is distinct from a typical waveform
(see FIG. 3) observed from cooperative technologies. According to a
supplemental, or alternative, embodiment, Wi-Fi device 104 is
further configured to monitor, detect, and/or identify correlating
information pertaining to performance of system 100 or Wi-Fi device
104 itself in order to enhance detection accuracy and aid in
further adaptation decisions. Such additional correlating
information includes, without limitation: (a) variation in received
noise strength patterns over time; (b) increases in latency (delay)
of Wi-Fi transmissions, the pattern of which may also vary over
time; (c) increases or pattern variations in packet error rates of
Wi-Fi transmissions; and (d) decreases or pattern variations of
Wi-Fi throughput.
[0030] In an exemplary embodiment, the information gathering
process utilized by Wi-Fi device 104 can be processed by a
processor (not shown) of Wi-Fi device 104, or alternatively at a
location of a central server (also not shown). In other
embodiments, the gathered information used for
detection/identification is aggregated across a number of
additional devices or servers (not shown in FIG. 1) in order to
provide further analytic and reporting capabilities. In one
embodiment, Wi-Fi device 104 is further configured to utilize the
gathered information to predict future transmission patterns
detected from non-cooperative technologies, due to the scheduled
and deterministic nature of such non-cooperative technologies,
which are thus more likely to remain stable over meaningful periods
of time. In an example, the pattern prediction process utilizes
prior patterns of detected non-cooperative protocols in the shared
spectrum, and extrapolates detected prior patterns estimate future
behavior.
[0031] FIG. 2 illustrates an effect of an exemplary duty cycle 200
of a periodic scheduled waveform on transmission parameters 202 for
shared spectrum system 100, as depicted in FIG. 1. In the example
illustration shown in FIG. 2, duty cycle 200 may include two OFF/ON
LTE sub-cycles, but for simplicity of explanation, only the first
LTE sub-cycle of duty cycle 200 is numbered and described.
Transmission parameters 202 may include, without limitation,
schedule traffic, noise levels, bit and/or packet errors, latency,
and Wi-Fi throughput. The schedule traffic may, for example, be
considered as without per packet contention mitigation, such as
from an LTE-U transmission signal (e.g., aggressive transmission
signal 114, FIG. 1).
[0032] In the exemplary embodiment, duty cycle 200 is first
described with respect to the LTE OFF state of the cycle. In the
LTE OFF state of a non-cooperative device (e.g., user equipment
102, FIG. 1), a transceiver of a cooperative device (e.g., Wi-Fi
device 104, FIG. 1) is configured to monitor schedule traffic 204,
noise levels 206, bit/packet errors 208, latency 210, and Wi-Fi
throughput 212. In the LTE ON state of the non-cooperative device,
however, the transceiver of the cooperative device detects an
increase A in schedule traffic 204', an increase B in noise levels
206', an increase C in bit/packet errors 208', an increase D in
latency 210', and a decrease E in Wi-Fi throughput 212'. Such
negative effects on transmission parameters 202 from the presence
of a non-cooperative transmission signal during the LTE ON state
contribute to the experienced interference (e.g., interference 116,
FIG. 1) of the cooperative Wi-Fi transmission (e.g., Wi-Fi
transmission 112, FIG. 1).
[0033] Referring to both FIGS. 1 and 2, Wi-Fi device 104 is
advantageously configured to implement one or more of the
adaptation techniques, described above, to mitigate the deleterious
effects on transmission parameters 202 experienced during the LTE
ON state of duty cycle 200. For each of the following adaptation
techniques, Wi-Fi device 104 is configured to listen to the shared
spectrum of system 100 and detect aggressive transmission signal
114. Wi-Fi device 104 is further configured to utilize the
information gathered through this detection process and assess the
current state of Wi-Fi device 104, Wi-Fi transmission 112, and
system 100, and calculate a likelihood that the performance of
Wi-Fi transmission 112 will be negatively impacted. In an exemplary
embodiment, the performance likelihood can be calculated utilizing
gathered information regarding, without limitation, throughput,
latency, packet loss, and other factors.
[0034] Utilizing the "do nothing" adaptation technique, when Wi-Fi
device 104 calculates that performance loss is unlikely, that is,
by consideration of the detected behavior of user equipment 102
and/or predetermined requirements of Wi-Fi device 104 at a
particular time, Wi-Fi device 104 may maintain the polite legacy
protocol without further adaptation. For this adaptation technique,
Wi-Fi device 104 responds to the detection and identification of
aggressive transmission signal 114 by making no additional change
to the operation of Wi-Fi device 104 and Wi-Fi transmission 112.
According to the "do nothing" adaptation technique, Wi-Fi device
104 does not adapt its own behavior, and instead remains in its
legacy distributed access protocol state.
[0035] Utilizing the avoidance adaptation technique, when Wi-Fi
device 104 calculates that performance will be negatively impacted
by the presence of aggressive transmission signal 114, Wi-Fi device
104 is additionally configured to change, or switch, its
transmission channel in order to avoid the frequency domain of
aggressive transmission signal 114. For this adaptation technique,
Wi-Fi device 104 is further configured to monitor system 100 and
utilize information regarding conditions of alternative available
channels. According to an exemplary embodiment, the conditions of
such alternative channels are assessed by Wi-Fi device 104 using
the listening functionality and detection processes described
above.
[0036] The scheduling adaptation technique may be implemented when
Wi-Fi device 104 calculates that performance will be negatively
impacted by the presence of aggressive transmission signal 114. For
this adaptation technique, Wi-Fi device 104 is additionally
configured to utilize predictive information gathered in the
detection process to avoid, or increase the likelihood of an
avoidance with, aggressive transmission signal 114 and the time
domain. In an exemplary embodiment, Wi-Fi device 104 monitors
aggressive transmission signal 114 to additionally calculate duty
cycle 200, and thereby schedule Wi-Fi transmission 112 to
synchronize its cooperative contention window to correspond to the
LTE OFF state of aggressive transmission signal 114. In one
embodiment, the scheduling adaptation technique is implemented in
place of, or to augment, the legacy distributed access protocol of
Wi-Fi device 104. In an alternative or supplemental embodiment, the
scheduling adaptation technique is further configured to adjust
transmission lengths of the contention window in order to optimize
for the length of the calculated LTE OFF state. The scheduling
adaptation technique is further described below with respect to
FIGS. 3 and 4.
[0037] The power adjustment adaptation technique may be implemented
when Wi-Fi device 104 calculates that performance will be
negatively impacted by the presence of aggressive transmission
signal 114. For this adaptation technique, Wi-Fi device 104 is
additionally configured to utilize predictive information gathered
in the detection process, and increase the transmission power of
Wi-Fi transmission 112 in order to maintain signal quality. In some
embodiments, the presence of aggressive transmission signal 114
creates interference 116 through the increased noise level 206',
which effectively "drowns out" Wi-Fi transmission 112. In an
exemplary embodiment, Wi-Fi device 104 overcomes the "drowning out"
effect by increasing the transmission power of Wi-Fi transmission
112 to maintain a sufficient signal-to-noise ratio to
metaphorically "speak louder" than aggressive transmission signal
114 over the shared spectrum of system 100. This power adjustment
adaptation technique is bound by certain limitations imposed by
governing regulatory restrictions. In practice, most cooperative
protocol transmissions operate sufficiently below the maximum
levels imposed by regulatory restrictions, such that this
adaptation technique is often available for use.
[0038] The throughput adjustment adaptation technique may be
implemented when Wi-Fi device 104 calculates that performance will
be negatively impacted by the presence of aggressive transmission
signal 114. For this adaptation technique, Wi-Fi device 104 is
additionally configured to reduce throughput of Wi-Fi transmission
112 in order to maintain reliability and performance of Wi-Fi
transmission 112 in consideration of particular transmission
parameters 202 such as latency 210, packet loss or errors 208,
and/or consistency of Wi-Fi throughput 212. In some embodiments,
cooperative technology systems include capability to adapt their
own throughput according to a range of factors unrelated to the
presence of non-cooperative technology. According to an exemplary
embodiment of this throughput adjustment adaptation technique,
Wi-Fi device 104 configured to utilize the detection process
described above, and further adjust the throughput according to the
detected and identified presence of aggressive transmission signal
114.
[0039] The reliability restoration adaptation technique may be
implemented when Wi-Fi device 104 calculates that performance will
be negatively impacted by the presence of aggressive transmission
signal 114. For this adaptation technique, Wi-Fi device 104 is
additionally configured to transmit Wi-Fi transmission 112 as
multiple, separate transmissions in order to overcome errors (e.g.
bit/packet errors 208) that may be more likely to occur from a
single instance of Wi-Fi transmission 112. By transmitting multiple
instances of Wi-Fi transmission 112, Wi-Fi device 104 is able to
restore the transmission errors and losses that may arise in a
single instance of Wi-Fi transmission 112 due to the presence of
aggressive transmission signal 114.
[0040] As described above, each of the foregoing adaptation
techniques may be implemented alone, or in combination with one or
more of the other techniques, based on the calculated likelihood of
negative performance impact from the presence of aggressive
transmission signal 114 within system 100. The calculation may be
based on the detected effect of aggressive transmission signal 114
itself, or may further consider other factors such as the relative
strength of Wi-Fi transmission 112, other capabilities of Wi-Fi
device 104, and/or operational considerations of system 100.
[0041] FIG. 3 is a graphical representation 300 of a cooperative
technology signal 302, according to an embodiment. In this example,
cooperative technology signal 302 may be a Wi-Fi transmission
(e.g., Wi-Fi transmission 112, FIG. 1), and is represented as a
function of received power 304 (y-axis), in units of
decibel-milliwatts (dBm), over time 306 (x-axis), in units of
seconds (s). In this example, cooperative technology signal 302,
without the presence of a non-cooperative technology signal, can be
seen to represent Wi-Fi energy generally clustered around the -120
dBm range. Cooperative technology signal 302 may, for example,
represent the output of a signal generator (not shown). In some
embodiments, the value of received power 304 is not confined purely
to a received signal strength indicator (RSSI), and may
alternatively include a combination of the RSSI, the noise floor,
and/or a smoothing factor.
[0042] FIG. 4 is a graphical representation 400 illustrating a
scheduling of a cooperative technology signal 402 in the presence
of a non-cooperative technology signal 404. In this example,
cooperative technology signal 402 may be similar to cooperative
technology signal 302 (FIG. 3), except that cooperative technology
signal 402 is adjusted to be limited, according to the scheduling
adaptation technique, described above, such that cooperative
technology signal 402 is synchronized to occur during the LTE OFF
state of a duty cycle 406 of non-cooperative technology signal 404.
In this example, non-cooperative technology signal 404 may be, for
example, an aggressive transmission signal similar to aggressive
transmission signal 114 (FIG. 1) for an LTE-U device (e.g., user
equipment 102, FIG. 1). Duty cycle 406 may, for example the
comparable to duty cycle 200 (FIG. 2).
[0043] With reference to the description above, in operation,
graphical representation 400 illustrates initially how the Wi-Fi
energy of cooperative technology signal 402 is still generally
clustered around the -120 dBm range, but is still significantly
impacted and negatively affected by the presence of non-cooperative
technology signal 404 when the signal generator (not shown) of a
corresponding device (e.g., user equipment 102, FIG. 1) is on (LTE
ON state, FIG. 2). That is, since the signal generator is operating
according to duty cycle 406, the transmission of non-cooperative
technology signal is typically performed according to a regular
time schedule. In other words, the LTE-U signal is transmitted only
according to this scheduled duty cycle 406, and does not implement
a polite LBT protocol or process prior to transmission within the
shared spectrum.
[0044] According to an exemplary embodiment, the transceiver of a
cooperative device (e.g., Wi-Fi device 104, FIG. 1) is configured
to "listen" for and detect the energy levels of both technology
signals 402, 404, and operate Wi-Fi device 104 to remain "silent"
(that is, not transmit) upon "hearing" the presence of the
interfering non-cooperative technology signal 404. However, Wi-Fi
device 104 is further configured, according to the present
embodiments, to additionally perform a dynamic analysis of gathered
data and information, and then determine more than just the
presence of noise from the interfering non-cooperative technology
signal 404. Wi-Fi device 104 is further to perform a dynamic
analysis gathered data and thus also calculate the duty cycle of
non-cooperative technology signal 404 and any resultant noise
therefrom.
[0045] Graphical representation 400 further illustrates how the
LTE-U energy is generally clustered around the -75 dBm range, and
also how duty cycle 406 can, after the calculation steps described
above, be easily superimposed upon non-cooperative technology
signal 404 within graphical representation 400. Such
superimposition of duty cycle 406 further exposes gap windows 408,
which appear between individual instances of clusters of
non-cooperative technology signal 404 around the -75 dBm range, and
for present timing portions within duty cycle 406 corresponding to
the LTE OFF state.
[0046] The determination and calculation of gap windows 408 is
therefore significant to at least the scheduling adaptive technique
described above. As shown in FIG. 4, interference from
non-cooperative technology signal 404 effectively disappears during
the LTE OFF state, thereby rendering the timeslots available within
gap windows 408 available for scheduling of cooperative technology
signal 402, where the cooperative technology will not experience
the deleterious effects of the aggressive transmission from
non-cooperative technology signal 404. In other words, the
contention window that is commonly utilized by cooperative
transmission technologies can be synchronized or narrowed only
occur during those times within gap windows 408. This scheduling
adaptation technique may be further implemented utilizing different
duty cycles, and also different power levels (which may, for
example, function to simulate different distances from node 106
(FIG. 1).
[0047] The novel systems and methods described above thus realize
significant advantages over conventional shared access systems by
implementing the adaptive contention and mitigation techniques for
shared access systems. Other advantages realized according the
present systems and methods include, without limitation, (a) a
CSMA/CA node (e.g., for Wi-Fi) that is configured to generally be
able to alter its coexistence behaviors based upon the presence of
other nodes and technologies within the shared spectrum, (b) a
CSMA/CA configuration for distributed control that can still be
applied in the presence of generally polite technologies, and (c) a
CSMA/CA figuration for the mitigating control in the presence of an
aggressive technology word node.
[0048] In one embodiment, when an aggressive node is detected, the
polite CSMA/CA node (or transceiver) is configured to mitigate the
effects of the interfering aggressive transmission signal by
implementing one or more of the following responses thereto,
including, without limitation: (1) Avoidance, where the cooperative
node moves/switches the cooperative transmission away from the
channel under aggressive traffic transmission conditions; (2)
"Leveling the Playing Field," where the cooperative node adapts
more aggressive techniques (e.g., power, throughput, etc.) in the
presence of other aggressive technologies so that all nodes have an
equivalent probability of sending traffic; and (3) Reliability
Restoration, in order to mitigate the impact of packet collisions
due to aggressive technologies to restore reliability. In the
exemplary embodiment, for each of these responses, the polite,
cooperative node (e.g., Wi-Fi device 104) continuously monitors the
channel of the shared spectrum, and is additionally configured to
adapt its coexistence contention transmission models/windows
accordingly.
[0049] Referring to FIGS. 1-2 and 4, an adaptive contention model
for shared access can be further applied with a Wi-Fi device (e.g.,
Wi-Fi device 104, FIG. 1), which contends with an LTE-U device
(e.g., user equipment and 102, FIG. 1) in the same shared spectrum.
The adaptive contention model implements one or more processes and
subprocesses for the contention relating to, without limitation,
monitoring, detection, determination, calculation, reporting,
mitigation, and adaptation.
[0050] In such instances, system 100 may be configured to implement
(through programming of a processor or similar device (not shown)
of the various elements, or by computer readable instructions from
the computer medium program) instructions to activate or respond to
the following events, which to not have to occur in order except
where indicated: (1) legacy operation of a Wi-Fi node; (2)
transmission by an LTE-U device; (3) detection of the LTE-U
transmission by the Wi-Fi node; (4) determination of spectrum
consumed by the LTE-U device; (5) calculation of the LTE-U
transmission timing; and (6) reporting of the LTE-U presence by the
Wi-Fi node.
[0051] More specifically, in the legacy operation process, a
cooperative Wi-Fi node (e.g., Wi-Fi device 104 or access point 108)
operates in the legacy state (also referred to as the reference, or
present, state), where the cooperative Wi-Fi node actively
transmits a cooperative transmission signal in the presence of
other, different, polite Wi-Fi nodes and technologies, utilizing
distributed access control of the shared spectrum channel within
system 100. During the LTE-U transmission process, the LTE-U device
(e.g., user equipment 102), begins transmission within the shared
spectrum band of system 100. In the LTE-U detection process, the
Wi-Fi node detects the presence of the LTE-U (e.g., by monitoring
the shared spectrum and measuring a signal strength of aggressive
transmission signal 114. In the determination process, the Wi-Fi
node utilizes its listening and analytic capabilities to determine
what percentage of the shared spectrum is consumed by the LTE-U
device/aggressive transmission signal. In the calculation process,
the Wi-Fi node utilizes gathered information to calculate the
transmission timing (e.g., duty cycle 200 or 406) of the
non-cooperative LTE-U transmission signal. In the reporting
process, the Wi-Fi node reports (e.g., through an alert system, not
shown) the presence of the LTE-U/aggressive transmission signal to
a user of Wi-Fi device 104 and/or to an owner of access point 108,
a central server, or a database affiliated with the Wi-Fi
technology.
[0052] In the exemplary embodiment, after completing the
determination process, Wi-Fi device 104 further implements one or
more mitigation strategies/techniques, as described above, to
compensate for the presence of aggressive transmission signal 114,
including, for example, an avoidance process and/or an adaptation
process. In the avoidance process, the Wi-Fi node selects a band or
channel that does not contain the non-cooperative LTE-U
transmission signal. In some embodiments, the avoidance process
further monitors for selected bands/channels that are not
considered to be already too congested. In an exemplary embodiment
of the adaptation process, the Wi-Fi node alters its own
transmission properties when LTE-U is transmitting in order to
realize an equal, or improved, opportunity to transmit. One example
of this adaptation technique is described above with respect to
FIG. 4.
[0053] According to the embodiment illustrated in FIG. 4, the
present systems and methods are advantageously capable of executing
a model for mitigation through adaptive contention by configuring
the Wi-Fi node to alter its transmission contention behavior during
LTE ON states/periods to gain an equal or improved opportunity for
channel transmission. In the exemplary embodiment, this particular
technique is applied when LTE-U is transmitting, that is, LTE ON.
The Wi-Fi node can be further configured to revert to legacy
behavior during the LTE OFF states/periods. According to this
example, the Wi-Fi device is rendered able to effectively transmit
data packets with ON/OFF duty cycles similar to the LTE-U device.
That is, the WI-Fi device may determine the LTE-U duty cycle (e.g.,
200, 406), and then adjust its packet transmissions for the same,
or a similar, duty cycle to increase the probability of
collision-free transmissions. According to this advantageous
scheduling technique, the Wi-Fi device is able to greatly reduce
clear channel assessment (CCA) and collision back off times, even
to near-zero values.
[0054] In some embodiments, this scheduling process may utilize
gathered information to predict both the LTE ON and LTE OFF state
transmissions, and thereby schedule a brief Wi-Fi transmission
frame (e.g., the contention window) immediately after the LTE-U
transmission switches from LTE ON to LTE OFF. In this example, a
processor of the Wi-Fi device determines the LTE-U duty cycle,
adjusts its packet transmissions accordingly during the predicted
LTE OFF state, and thus CCA and collision back off procedures are
updated such that the procedures are executed only when the duty
cycle of the LTE-U transmission is off and the chance of collision
with other WI-FI networks increases. According to this advantageous
process, Wi-Fi devices and access points capable of synchronizing
Wi-Fi transmissions with LTE-U transmissions, and intentionally
schedule Wi-Fi (cooperative signal) traffic when the duty cycle of
the LTE-U transmission is off (LTE OFF).
[0055] As described above, a Wi-Fi device according to the
embodiments disclosed herein is further advantageously capable of
performing additional, and/or alternative adaptation mitigation
actions, processes, and techniques when detecting a non-cooperative
transmission in an LTE ON state. For example, the Wi-Fi device can
be further configured to transmit at a lower modulation and coding
scheme (MCS) to overcome encountered bit errors in the Wi-Fi
transmission. In this example, the Wi-Fi device shifts or switches
to a lower MCS to overcome the bit errors that occur due to LTE-U
collisions. The lower MCS produces a lower, but more reliable,
Wi-Fi throughput in the face of increased LTE-U collisions.
[0056] In another example, the Wi-Fi device is further configured
to transmit redundant data packets to overcome packets lost due to
transmission interference caused by the presence of an aggressive
transmission signal. The transmission of redundant data packets
serves to improve transmission reliability in the face of increases
in LTE-U transmissions. The redundant data packets may, for
example, be transmitted from the access point to the Wi-Fi device,
or from the Wi-Fi device to the access point according to this
embodiment.
[0057] In another example, the Wi-Fi device is further configured
to reduce medium access control (MAC) layer frame sizes to increase
successful reception of the transmitted Wi-Fi signal. By
calculating the time when the periodic LTE-U transmissions are off
(LTE OFF), the Wi-Fi device is capable of further adjusting the
Wi-Fi MAC frame size to optimally occur within the period of the
LTE OFF state, and thereby increase the probability of
collision-free Wi-Fi transmissions. In an additional example, the
Wi-Fi device is further configured to apply LTE-U interference
cancellation at Wi-Fi receiver portions by subtracting the
predicted LTE-U energy profile from the received Wi-Fi
transmissions. Each and all of these exemplary mitigation
techniques may be further configured to adjust the particular
mitigation strategy in consideration of the Wi-Fi throughput.
[0058] According to the advantageous systems and methods disclosed
herein, a Wi-Fi device, node, or transceiver is capable of
realizing adaptation techniques for shared channel access models
and mechanisms based upon the detection of aggressive technologies
on the channel. The present systems and methods are further capable
of dynamically moving a Wi-Fi transmission from one shared channel
access model to another and back again based upon the cooperative
and non-cooperative technologies detected and identified on the
channel of the shared spectrum.
[0059] According to the disclosed embodiments, the Wi-Fi device may
detect the presence of scheduled, that is, non-cooperative,
technologies on the shared spectrum channel, and then identify
LTE-U signatures in terms of one or more of (i) periodically
variable received noise strength as function of time, (ii) shifts
in latency impact to Wi-Fi transmissions as a function of time,
(iii) periodic shifts in bit or packet error rates as a function of
time, and (iv) periodic shifts in Wi-Fi throughput. Once the LTE-U
transmission is detected and identified, a Wi-Fi device according
to the disclosed embodiments is further advantageously capable of
predicting future LTE-U transmissions based upon detected periodic
disturbance(s) of the Wi-Fi performance parameters or indicators.
Reliability of the detection may be improved by consideration of
more than one of the parameters/indicators together. Once the
determination and prediction processes are accurately completed,
the Wi-Fi device according to the disclosed embodiments is able to
implement one or more of the advantageous mitigation techniques and
processes described above, whether simultaneously or in
succession.
[0060] Exemplary embodiments of shared access communication
management systems and methods are described above in detail. The
systems and methods of this disclosure though, are not limited to
only the specific embodiments described herein, but rather, the
components and/or steps of their implementation may be utilized
independently and separately from other components and/or steps
described herein.
[0061] Although specific features of various embodiments of the
disclosure may be shown in some drawings and not in others, this
convention is for convenience purposes and ease of description
only. In accordance with the principles of the disclosure, a
particular feature shown in a drawing may be referenced and/or
claimed in combination with features of the other drawings.
[0062] Some embodiments involve the use of one or more electronic
or computing devices. Such devices typically include a processor or
controller, such as a general purpose central processing unit
(CPU), a graphics processing unit (GPU), a microcontroller, a
reduced instruction set computer (RISC) processor, an application
specific integrated circuit (ASIC), a programmable logic circuit
(PLC), a field programmable gate array (FPGA), a digital signal
processing (DSP) device, and/or any other circuit or processor
capable of executing the functions described herein. The processes
described herein may be encoded as executable instructions embodied
in a computer readable medium, including, without limitation, a
storage device and/or a memory device. Such instructions, when
executed by a processor, cause the processor to perform at least a
portion of the methods described herein. The above examples are
exemplary only, and thus are not intended to limit in any way the
definition and/or meaning of the term "processor."
[0063] This written description uses examples to disclose the
embodiments, including the best mode, and also to enable any person
skilled in the art to practice the embodiments, including making
and using any devices or systems and performing any incorporated
methods. The patentable scope of the disclosure is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
* * * * *