U.S. patent application number 17/052328 was filed with the patent office on 2021-06-10 for wireless transmit receive unit (wtru) reachability.
This patent application is currently assigned to IDAC HOLDINGS, INC. The applicant listed for this patent is IDAC HOLDINGS, INC. Invention is credited to Faris Alfarhan, Aata El Ha mss, Paul Marinier, Ghyslain Pelletier, J. Patrick Tooher.
Application Number | 20210176710 17/052328 |
Document ID | / |
Family ID | 1000005472989 |
Filed Date | 2021-06-10 |
United States Patent
Application |
20210176710 |
Kind Code |
A1 |
Tooher; J. Patrick ; et
al. |
June 10, 2021 |
WIRELESS TRANSMIT RECEIVE UNIT (WTRU) REACHABILITY
Abstract
A wireless transmit/receive unit (WTRU) may receive/transmit
data by employing a discontinuous reception cycle, which may
include an awake state and a sleep state. For example, while in an
awake state, a WTRU may monitor a PDCCH for a subset of time
instances. During the remaining time instances, the WTRU may enter
a sleep state, in which the WTRU may switch its receiving circuitry
off (e.g., to reduce power consumption). A WTRU may receive (e.g.,
may expect to receive) one or more transmissions, during an awake
state, before entering a sleep state. The durations of an awake
state and/or the durations of subsequent sleep states may be
determined based on whether the WTRU receives a transmission during
the awake state and/or what the transmission was for. The WTRU may
modify the value of a sleep state timer based on previous sleep
state and/or awake state timer values.
Inventors: |
Tooher; J. Patrick;
(Montreal, CA) ; Marinier; Paul; (Brossard,
CA) ; Pelletier; Ghyslain; (Montreal, CA) ;
Alfarhan; Faris; (Montreal, CA) ; El Ha mss;
Aata; (Laval, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDAC HOLDINGS, INC, |
Wilmington |
DE |
US |
|
|
Assignee: |
IDAC HOLDINGS, INC,
Wilmington
DE
|
Family ID: |
1000005472989 |
Appl. No.: |
17/052328 |
Filed: |
May 6, 2019 |
PCT Filed: |
May 6, 2019 |
PCT NO: |
PCT/US2019/030815 |
371 Date: |
November 2, 2020 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62668571 |
May 8, 2018 |
|
|
|
62715390 |
Aug 7, 2018 |
|
|
|
62752119 |
Oct 29, 2018 |
|
|
|
62787960 |
Jan 3, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/1273 20130101;
H04W 68/005 20130101; H04W 52/0274 20130101; H04W 72/1289 20130101;
H04W 76/28 20180201 |
International
Class: |
H04W 52/02 20060101
H04W052/02; H04W 72/12 20060101 H04W072/12; H04W 76/28 20060101
H04W076/28; H04W 68/00 20060101 H04W068/00 |
Claims
1. A wireless transmit/receive unit (WTRU), the WTRU comprising: a
memory; and a processor configured to: monitor a channel for a
plurality of types of signals during a first monitoring period,
wherein the plurality of types of signals comprises a first type of
signal and a second type of signal, and wherein the first type of
signal comprises an indication that indicates the channel has been
acquired, and the second type of signal comprises a message that
comprises scheduling information for a transmission to or from the
WTRU on the channel; on a condition that the first type of signal
is received during the first monitoring period, determine that a
second monitoring period will occur at a first time; and on a
condition that the first type of signal is not received during the
first monitoring period, determine that the second monitoring
period will occur at a second time, the second time being earlier
than the first time.
2. The WTRU of claim 1, wherein a minimum duration of the second
monitoring period is a first duration on a condition that the first
type of signal but not the second type of signal is received during
the first monitoring period, and the minimum duration of the second
monitoring period is a second duration on a condition that neither
the first type of signal nor the second type of signal is received
during the first monitoring period, the first duration being longer
than the second duration.
3. The WTRU of claim 1, wherein the processor is configured to: on
a condition that the second type of signal is received during the
first monitoring period, send or receive the transmission based on
the scheduling information.
4. The WTRU of claim 1, wherein the channel is comprised in an
unlicensed band.
5. The WTRU of claim 1, wherein the first type of signal comprises
a reference signal (RS).
6. The WTRU of claim 1, wherein the first type of signal comprises
downlink control information (DCI) indicating that the channel has
been acquired.
7. The WTRU of claim 1, wherein the first and second monitoring
periods correspond to active periods of a discontinuous reception
(DRX) cycle, and a time between an end of the first monitoring
period and a start of the second monitoring period corresponds to a
sleep period of the DRX cycle, and wherein the first time is
determined based on a long DRX cycle configuration and the second
time is determined based on a short DRX cycle configuration.
8. The WTRU of claim 1, wherein the first monitoring period
corresponds to a first paging occasion and the second monitoring
period corresponds to a second paging occasion.
9. The WTRU of claim 8, wherein the processor is further configured
to: activate a conditional paging occasion for the second paging
occasion during the second monitoring period to monitor the channel
based on not receiving the first type of signal.
10. The WTRU of claim 1, wherein the processor is configured to:
determine the first type of signal as an indication that indicates
the WTRU can go to sleep until a start of the second monitoring
period based on a condition that the first type of signal but not
the second type of signal is received during the first monitoring
period.
11. A method comprising: monitoring a channel, by a wireless
transmit/receive unit (WTRU), for a plurality of types of signals
during a first monitoring period, wherein the plurality of types of
signals comprises a first type of signal and a second type of
signal, and wherein the first type of signal comprises an
indication that indicates the channel has been acquired, and the
second type of signal comprises a message that comprises scheduling
information for a transmission to or from the WTRU on the channel;
on a condition that the first type of signal is received during the
first monitoring period, determining that a second monitoring
period will occur at a first time based; and on a condition that
the first type of signal is not received during the first
monitoring period, determining that the second monitoring period
will occur at a second time, the second time being earlier than the
first time.
12. The method of claim 11, wherein a minimum duration of the
second monitoring period is a first duration on a condition that
the first type of signal but not the second type of signal is
received during the first monitoring period, and the minimum
duration of the second monitoring period is a second duration on a
condition that neither the first type of signal nor the second type
of signal is received during the first monitoring period, the first
duration having longer duration than the second duration.
13. The method of claim 11, wherein the first and second monitoring
periods correspond to active periods of a discontinuous reception
(DRX) cycle, and a time between an end of the first monitoring
period and a start of the second monitoring period corresponds to a
sleep period of the DRX cycle, and wherein the first time is
determined based on a long DRX cycle configuration and the second
time is determined based on a short DRX cycle configuration.
14. The method of claim 11, wherein the first monitoring period
corresponds to a first paging occasion and the second monitoring
period corresponds to a second paging occasion.
15. A wireless transmit/receive unit (WTRU), the WTRU comprising: a
memory; and a processor configured to: monitor a channel for a
plurality of types of signals during a first monitoring period,
wherein the plurality of types of signals comprises a first type of
signal and a second type of signal, and wherein the first type of
signal comprises an indication that indicates the channel has been
acquired, and the second type of signal comprises a message that
comprises scheduling information for a transmission to or from the
WTRU on the channel; on a condition that the first type of signal
but not the second type of signal is received during the first
monitoring period, determine that a second monitoring period will
occur at a first time; and on a condition that neither the first
type of signal nor the second type of signal is received during the
first monitoring period, determine that the second monitoring
period will occur at a second time, the second time being earlier
than the first time.
16. The WTRU of claim 15, wherein the first and second monitoring
periods correspond to active periods of a discontinuous reception
(DRX) cycle, and a time between an end of the first monitoring
period and a start of the second monitoring period corresponds to a
sleep period of the DRX cycle, and wherein the first time is
determined based on a long DRX cycle configuration and the second
time is determined based on a short DRX cycle configuration.
17. The WTRU of claim 15, wherein the first monitoring period
corresponds to a first paging occasion and the second monitoring
period corresponds to a second paging occasion.
18. The method of claim 11, wherein the channel is comprised in an
unlicensed band, and wherein the first type of signal comprises at
least one of a reference signal (RS) or downlink control
information (DCI) indicating that the channel has been
acquired.
19. The method of claim 14, further comprising: activating a
conditional paging occasion for the second paging occasion during
the second monitoring period to monitor the channel based on not
receiving the first type of signal.
20. The method of claim 11, comprising: determining the first type
of signal as an indication indicating that the WTRU can go to sleep
until a start of the second monitoring period based on a condition
that the first type of signal but not the second type of signal is
received during the first monitoring period.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 62/668,571 filed May 8, 2018, U.S. Provisional
Application Ser. No. 62/715,390 filed Aug. 7, 2018, U.S.
Provisional Application Ser. No. 62/752,119 filed Oct. 29, 2018,
and U.S. Provisional Application Ser. No. 62/787,960 filed Jan. 3,
2019, the contents of which are incorporated by reference
herein.
BACKGROUND
[0002] Operation in an unlicensed frequency band may be subject to
limits. For example, in an unlicensed transmission, there may be
limits on one or more of transmit power, radio frequency (RF)
output power, power density given by the mean Equivalent
Isotropically Radiated Power (EIRP), the mean EIRP density at the
highest power level, and/or the like. Operation in an unlicensed
frequency band may further be subject to requirements on out of
band emissions of the transmitter, which may be specific to bands
and/or geographical locations.
[0003] Operation in an unlicensed frequency band may be subject to
requirements on the Nominal Channel Bandwidth (NCB) and the
Occupied Channel Bandwidth (OCB) that are defined for the
unlicensed spectrum (e.g., the unlicensed spectrum in a 5 GHz
region). The NCB may correspond to the widest band of frequencies.
The NCB may include the guard bands assigned to a channel. For
example, the guard band may be approximately 5 MHz (e.g., may be at
least 5 MHz at all times). The OCB may be the bandwidth containing
the large majority of the power of the signal (e.g., on order of
approximately 99% of signal power). The OCB may correspond to
approximately 80% to 100% of the declared NCB. During an
established communication session for example, a device may operate
temporarily in a mode where the OCB of the device may be reduced.
For example, the OCB may be reduced to approximately 40% of its
NCB. In many scenarios, the OCB of the device may have a minimum
bandwidth of approximately 4 MHz.
[0004] Listen-Before-Talk (LBT) may be performed to facilitate
channel access in an unlicensed frequency band. LBT may be
performed independently of whether or not the channel is
occupied.
[0005] LBT may be implemented using LBT frame-based systems. An LBT
system may be characterized by one or more of the following. An LBT
system may be characterized by a Clear Channel Assessment (CCA)
time. For example, 20 .mu.s may be a typical CCA time. An LBT
system may be characterized by a Channel Occupancy time. For
example, a typical minimum channel occupancy time may be
approximately 1 ms and a typical maximum channel occupancy time may
be approximately of 10 ms. An LBT system may be characterized by an
idle period. For example, a typical idle period between
transmissions may be approximately minimum 5% of channel occupancy
time. An LBT system may be characterized by a fixed frame period.
For example, the fixed frame period may correspond to the channel
occupancy time and the idle period. An LBT system may be
characterized by a short control signaling transmission time. For
example, a typical control signaling transmission time may be
associated with a maximum duty cycle of 5% within an observation
period of 50 ms. An LBT system may be characterized by a CCA energy
detection threshold.
[0006] In a wireless communication system(s) (e.g., a new radio
(NR) system), discontinuous reception (DRX) may reduce wireless
transmit/receive unit (WTRU) power consumption. For example, when a
WTRU is in connected mode DRX, the WTRU may be configured with a
DRX cycle. When the WTRU is in the DRX cycle, the WTRU may monitor
the physical downlink control channel (PDCCH) for a subset of time
instances, and during the remaining time instances, the WTRU may
sleep (e.g., not monitor) during not monitoring periods. To save
power, the WTRU may operate with the receiver circuitry switched
off during periods where it is not required to monitor the control
channel. When the WTRU receives scheduling information in its PDCCH
during a monitoring portion of the cycle, the WTRU may continue to
monitor the PDCCH until, for example, the WTRU determines that no
scheduling is expected. The sleep duration may be directly
proportional to the power savings. For example, the longer the
sleep duration, the larger the reduction in WTRU power consumption.
Scheduling restrictions may apply and/or may affect efficiency.
SUMMARY
[0007] Systems, methods, and/or instrumentalities are disclosed for
determining times during which a wireless transmit/receive unit
(WTRU) should monitor for signaling and/or periods during which no
signaling is expected (e.g., when the WTRU can sleep). The systems
and techniques described herein may be used by a WTRU to implement
discontinuous reception (DRX) operation (e.g., either in connected
and/or idle modes), determine when to expect control signaling,
determine when to expect paging signaling, and/or the like. The
techniques described herein may be used when the WTRU is operating
on an unlicensed and/or otherwise contentious channel.
[0008] A WTRU may be configured to determine timing associated with
a monitoring period (e.g., a start time of a subsequent monitoring
period or a second monitoring period). For example, a WTRU may be
configured to determine timing associated with a monitoring period
based on a signal(s) received during a previous monitoring period
(e.g., a first monitoring period). A WTRU may monitor a channel
(e.g., an unlicensed channel) for a signal(s) associated with a
transmission during a monitoring period (e.g., a first monitoring
period). Based on the signal(s) received during the monitoring
period (e.g., the first monitoring period), the WTRU may determine
a time (e.g., a start time) of a subsequent monitoring period
(e.g., a second monitoring period). For example, the WTRU may
monitor for a signal(s) during the monitoring period for a signal
for an indication that the channel has been acquired (e.g., a
channel acquisition indication and/or signal) and/or a signal for a
message that includes scheduling information for a transmission to
and/or from the WTRU on the channel. A reference signal (RS) may be
an example signal for the indication that the channel has been
acquired. Downlink control information may be an example signal for
the indication that the channel has been acquired.
[0009] The WTRU may determine a subsequent monitoring period (e.g.,
a second monitoring period) based on the signals received during
the previous monitoring period (e.g., the first monitoring period).
The WTRU may determine that the subsequent monitoring period (e.g.,
the second monitoring period) may occur at a first time based on
receiving the signal that indicates the channel has been acquired
during the first monitoring period. The WTRU may determine that the
subsequent monitoring period (e.g., the second monitoring period)
may occur at a second time based on not receiving the signal that
indicates the channel acquisition during the first monitoring
period. The WTRU may send or receive a transmission on the channel
based on receiving the signal for the channel acquisition and the
message that includes scheduling information.
[0010] The WTRU may determine a duration (e.g., a minimum duration)
of the second monitoring period to a first duration based on
receiving the signal for channel acquisition but not receiving the
signal for the message including scheduling information for the
transmission to and/or from the WTRU on the channel during the
first monitoring period. The WTRU may determine the duration (e.g.,
the minimum duration) of the second monitoring period to the second
duration based on not receiving the signal for channel acquisition
and not receiving the signal for the message including scheduling
information for the transmission to and/or from the WTRU on the
channel during the first monitoring period. The first duration may
be longer than the second duration.
[0011] In examples, the first and the second monitoring periods
described herein may correspond to active periods of DRX cycles.
For example, the first and the second monitoring periods described
herein may correspond to on durations of a DRX cycle. A time
between an end of the first monitoring period and a start of the
second monitoring period may correspond to a sleep period of the
DRX cycles. The WTRU may determine the first time the WTRU
receiving the channel acquisition signal during the first
monitoring period. For example, the WTRU may determine the first
time the WTRU receiving the channel acquisition signal based on a
long DRX cycle configuration. The WTRU may determine the second
time the WTRU not receiving the channel acquisition signal during
the first monitoring period. For example, the WTRU may determine
the second time the WTRU not receiving the channel acquisition
signal during based on a short DRX cycle configuration.
[0012] In examples, the first and the second monitoring periods
described herein may correspond to a first paging occasion and a
second paging occasion, respectively.
[0013] The WTRU may consider an indication (e.g., in the channel
acquisition signal) that the WTRU may go to sleep until a start of
the second monitoring period based on the WTRU receiving the
channel acquisition signal (e.g., but not receiving the signal for
the message for scheduling information for the transmission) during
the first monitoring period.
[0014] A WTRU may receive/transmit data by employing a
discontinuous reception cycle, for example for use in operation in
an unlicensed band, DRX operation may include an awake state and a
sleep state. For example, while in an awake state, a WTRU may
monitor a physical downlink control channel (PDCCH) for a subset of
time instances. During the remaining time instances, the WTRU may
enter a sleep state, in which the WTRU may not be required to
monitor the PDCCH. During the sleep period, the WTRU may switch off
receiving circuitry to reduce power consumption. A WTRU may receive
(e.g., may expect to receive) one or more transmissions during an
awake state. For example, a WTRU may receive one or more
transmissions during an awake state before entering a sleep state.
The durations of an awake state and/or the durations of subsequent
sleep states may be determined based on whether the WTRU receives a
transmission during the awake state and/or what the transmission
was for. The WTRU may modify the value of a sleep state timer based
on one or more of previous sleep state, awake state timer values,
or received transmission(s) during the awake state. The WTRU may
receive an indication for an aperiodic paging occasion (PO) timing
during a PO.
[0015] The DRX operation may be used to support operation in an
unlicensed band. For example, DRX operation may be defined such
that Listen-Before-Talk (LBT) is performed as part of or in
conjunction with DRX operation. DRX timing and reception rules may
be implemented such that the WTRU is able to differentiate between
scenarios where the WTRU was not scheduled via the PDCCH or other
control channel (e.g., because the network did not have a
transmission for the WTRU) versus when the WTRU was not sent a
transmission due to lack of channel acquisition by the network
(e.g., despite having a transmission for the WTRU). The rules may
be defined to balance between WTRU reachability/latency and power
savings.
[0016] The DRX rules and configurations may be applicable to New
Radio (NR) operation in an unlicensed band (e.g., 5G operation in
an unlicensed band).
[0017] A WTRU may determine one or more parameters of a current
and/or upcoming DRX cycle based on the presence and/or absence of a
signal during a current awake period. Based on the determination,
the WTRU may provide more opportunities to a network to acquire a
channel to reach the WTRU.
[0018] For example, one or more of the following may be performed.
The WTRU may be configured with multiple DRX durations. The WTRU
may wake up from a DRX cycle at expiration of a first timer. The
WTRU may monitor a presence of a signal. For example, the WTRU may
monitor whether a PDCCH transmission to assign resources or page a
WTRU and/or a transmission indicating the cell acquired the
unlicensed channel. If the WTRU receives a signal indicating that a
channel has been acquired and no other transmission, the WTRU may
return to DRX, for example using a first DRX duration. If the WTRU
does not receive a (e.g., any) transmission from the cell, the WTRU
may return to DRX, for example using a second DRX duration.
[0019] A WTRU may determine one or more parameters of a current
and/or upcoming DRX cycle based on the reception, or lack thereof,
of a signal in a previous or current awake period.
[0020] A WTRU may receive an indication to enter (e.g., immediately
enter) DRX state (e.g., at conclusion of channel occupancy
(COT)).
[0021] A WTRU may determine the timing of an aperiodic PF based on
the reception, or lack thereof, of a signal during a previous
paging frame (PF).
[0022] A WTRU may receive an indication in a PF of the timing of an
upcoming aperiodic PF.
[0023] Paging occasion(s) and/or paging frame(s) (e.g., conditional
paging occasion(s) and/or paging frame(s)) may be triggered. The
activation or deactivation of a conditional paging occasion (PO)
and/or a conditional PF may be based on one or more of the
following. The activation or deactivation of a conditional PO
and/or a conditional PF may be based on reception of a signal or
lack of reception a signal in a (e.g., previous and/or associated)
PO and/or PF. The activation or deactivation of a conditional PO
and/or a conditional PF may be based on reception of a signal prior
to the conditional PO and/or PF. The activation or deactivation of
a conditional PO and/or a conditional PF may be based on one or
more measurements. The activation or deactivation of a conditional
PO and/or a conditional PF may be based on one or more network
indications. The activation or deactivation of a conditional PO
and/or a conditional PF may be based on a time. The activation or
deactivation of a conditional PO and/or a conditional PF may be
based on a WTRU state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1A is a system diagram illustrating an example
communications system in which one or more disclosed embodiments
may be implemented.
[0025] FIG. 1B is a system diagram illustrating an example wireless
transmit/receive unit (WTRU) that may be used within the
communications system illustrated in FIG. 1A according to an
embodiment.
[0026] FIG. 1C is a system diagram illustrating an example radio
access network (RAN) and an example core network (CN) that may be
used within the communications system illustrated in FIG. 1A
according to an embodiment.
[0027] FIG. 1D is a system diagram illustrating a further example
RAN and a further example CN that may be used within the
communications system illustrated in FIG. 1A according to an
embodiment.
[0028] FIG. 2 is an example of an adaptive discontinuous reception
(DRX) cycle.
[0029] FIG. 3 illustrates an example flowchart for DRX timer
determination based on wakeup signal detection.
DETAILED DESCRIPTION
[0030] A detailed description of illustrative embodiments will now
be described with reference to the various Figures. Although this
description provides a detailed example of possible
implementations, it should be noted that the details are intended
to be exemplary and in no way limit the scope of the
application.
[0031] FIG. 1A is a diagram illustrating an example communications
system 100 in which one or more disclosed embodiments may be
implemented. The communications system 100 may be a multiple access
system that provides content, such as voice, data, video,
messaging, broadcast, etc., to multiple wireless users. The
communications system 100 may enable multiple wireless users to
access such content through the sharing of system resources,
including wireless bandwidth. For example, the communications
systems 100 may employ one or more channel access methods, such as
code division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal FDMA
(OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word
DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM),
resource block-filtered OFDM, filter bank multicarrier (FBMC), and
the like.
[0032] As shown in FIG. 1A, the communications system 100 may
include wireless transmit/receive units (WTRUs) 102a, 102b, 102c,
102d, a RAN 104/113, a CN 106/115, a public switched telephone
network (PSTN) 108, the Internet 110, and other networks 112,
though it will be appreciated that the disclosed embodiments
contemplate any number of WTRUs, base stations, networks, and/or
network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be
any type of device configured to operate and/or communicate in a
wireless environment. By way of example, the WTRUs 102a, 102b,
102c, 102d, any of which may be referred to as a "station" and/or a
"STA", may be configured to transmit and/or receive wireless
signals and may include a user equipment (UE), a mobile station, a
fixed or mobile subscriber unit, a subscription-based unit, a
pager, a cellular telephone, a personal digital assistant (PDA), a
smartphone, a laptop, a netbook, a personal computer, a wireless
sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT)
device, a watch or other wearable, a head-mounted display (HMD), a
vehicle, a drone, a medical device and applications (e.g., remote
surgery), an industrial device and applications (e.g., a robot
and/or other wireless devices operating in an industrial and/or an
automated processing chain contexts), a consumer electronics
device, a device operating on commercial and/or industrial wireless
networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d
may be interchangeably referred to as a UE.
[0033] The communications systems 100 may also include a base
station 114a and/or a base station 114b. Each of the base stations
114a, 114b may be any type of device configured to wirelessly
interface with at least one of the WTRUs 102a, 102b, 102c, 102d to
facilitate access to one or more communication networks, such as
the CN 106/115, the Internet 110, and/or the other networks 112. By
way of example, the base stations 114a, 114b may be a base
transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a
Home eNode B, a gNB, a NR NodeB, a site controller, an access point
(AP), a wireless router, and the like. While the base stations
114a, 114b are each depicted as a single element, it will be
appreciated that the base stations 114a, 114b may include any
number of interconnected base stations and/or network elements.
[0034] The base station 114a may be part of the RAN 104/113, which
may also include other base stations and/or network elements (not
shown), such as a base station controller (BSC), a radio network
controller (RNC), relay nodes, etc. The base station 114a and/or
the base station 114b may be configured to transmit and/or receive
wireless signals on one or more carrier frequencies, which may be
referred to as a cell (not shown). These frequencies may be in
licensed spectrum, unlicensed spectrum, or a combination of
licensed and unlicensed spectrum. A cell may provide coverage for a
wireless service to a specific geographical area that may be
relatively fixed or that may change over time. The cell may further
be divided into cell sectors. For example, the cell associated with
the base station 114a may be divided into three sectors. Thus, in
one embodiment, the base station 114a may include three
transceivers, i.e., one for each sector of the cell. In an
embodiment, the base station 114a may employ multiple-input
multiple output (MIMO) technology and may utilize multiple
transceivers for each sector of the cell. For example, beamforming
may be used to transmit and/or receive signals in desired spatial
directions.
[0035] The base stations 114a, 114b may communicate with one or
more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116,
which may be any suitable wireless communication link (e.g., radio
frequency (RF), microwave, centimeter wave, micrometer wave,
infrared (IR), ultraviolet (UV), visible light, etc.). The air
interface 116 may be established using any suitable radio access
technology (RAT).
[0036] More specifically, as noted above, the communications system
100 may be a multiple access system and may employ one or more
channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA,
and the like. For example, the base station 114a in the RAN 104/113
and the WTRUs 102a, 102b, 102c may implement a radio technology
such as Universal Mobile Telecommunications System (UMTS)
Terrestrial Radio Access (UTRA), which may establish the air
interface 115/116/117 using wideband CDMA (WCDMA). WCDMA may
include communication protocols such as High-Speed Packet Access
(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed
Downlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet
Access (HSUPA).
[0037] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement a radio technology such as Evolved UMTS
Terrestrial Radio Access (E-UTRA), which may establish the air
interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced
(LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).
[0038] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement a radio technology such as NR Radio
Access, which may establish the air interface 116 using New Radio
(NR).
[0039] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement multiple radio access technologies. For
example, the base station 114a and the WTRUs 102a, 102b, 102c may
implement LTE radio access and NR radio access together, for
instance using dual connectivity (DC) principles. Thus, the air
interface utilized by WTRUs 102a, 102b, 102c may be characterized
by multiple types of radio access technologies and/or transmissions
sent to/from multiple types of base stations (e.g., an eNB and a
gNB).
[0040] In other embodiments, the base station 114a and the WTRUs
102a, 102b, 102c may implement radio technologies such as IEEE
802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e.,
Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,
CDMA2000 1x, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000),
Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global
System for Mobile communications (GSM), Enhanced Data rates for GSM
Evolution (EDGE), GSM EDGE (GERAN), and the like.
[0041] The base station 114b in FIG. 1A may be a wireless router,
Home Node B, Home eNode B, or access point, for example, and may
utilize any suitable RAT for facilitating wireless connectivity in
a localized area, such as a place of business, a home, a vehicle, a
campus, an industrial facility, an air corridor (e.g., for use by
drones), a roadway, and the like. In one embodiment, the base
station 114b and the WTRUs 102c, 102d may implement a radio
technology such as IEEE 802.11 to establish a wireless local area
network (WLAN). In an embodiment, the base station 114b and the
WTRUs 102c, 102d may implement a radio technology such as IEEE
802.15 to establish a wireless personal area network (WPAN). In yet
another embodiment, the base station 114b and the WTRUs 102c, 102d
may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,
LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As
shown in FIG. 1A, the base station 114b may have a direct
connection to the Internet 110. Thus, the base station 114b may not
be required to access the Internet 110 via the CN 106/115.
[0042] The RAN 104/113 may be in communication with the CN 106/115,
which may be any type of network configured to provide voice, data,
applications, and/or voice over internet protocol (VoIP) services
to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may
have varying quality of service (QoS) requirements, such as
differing throughput requirements, latency requirements, error
tolerance requirements, reliability requirements, data throughput
requirements, mobility requirements, and the like. The CN 106/115
may provide call control, billing services, mobile location-based
services, pre-paid calling, Internet connectivity, video
distribution, etc., and/or perform high-level security functions,
such as user authentication. Although not shown in FIG. 1A, it will
be appreciated that the RAN 104/113 and/or the CN 106/115 may be in
direct or indirect communication with other RANs that employ the
same RAT as the RAN 104/113 or a different RAT. For example, in
addition to being connected to the RAN 104/113, which may be
utilizing a NR radio technology, the CN 106/115 may also be in
communication with another RAN (not shown) employing a GSM, UMTS,
CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.
[0043] The CN 106/115 may also serve as a gateway for the WTRUs
102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110,
and/or the other networks 112. The PSTN 108 may include
circuit-switched telephone networks that provide plain old
telephone service (POTS). The Internet 110 may include a global
system of interconnected computer networks and devices that use
common communication protocols, such as the transmission control
protocol (TCP), user datagram protocol (UDP) and/or the internet
protocol (IP) in the TCP/IP internet protocol suite. The networks
112 may include wired and/or wireless communications networks owned
and/or operated by other service providers. For example, the
networks 112 may include another CN connected to one or more RANs,
which may employ the same RAT as the RAN 104/113 or a different
RAT.
[0044] Some or all of the WTRUs 102a, 102b, 102c, 102d in the
communications system 100 may include multi-mode capabilities
(e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple
transceivers for communicating with different wireless networks
over different wireless links). For example, the WTRU 102c shown in
FIG. 1A may be configured to communicate with the base station
114a, which may employ a cellular-based radio technology, and with
the base station 114b, which may employ an IEEE 802 radio
technology.
[0045] FIG. 1B is a system diagram illustrating an example WTRU
102. As shown in FIG. 1B, the WTRU 102 may include a processor 118,
a transceiver 120, a transmit/receive element 122, a
speaker/microphone 124, a keypad 126, a display/touchpad 128,
non-removable memory 130, removable memory 132, a power source 134,
a global positioning system (GPS) chipset 136, and/or other
peripherals 138, among others. It will be appreciated that the WTRU
102 may include any sub-combination of the foregoing elements while
remaining consistent with an embodiment.
[0046] The processor 118 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Arrays (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 118 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the WTRU 102 to operate in a wireless environment. The
processor 118 may be coupled to the transceiver 120, which may be
coupled to the transmit/receive element 122. While FIG. 1B depicts
the processor 118 and the transceiver 120 as separate components,
it will be appreciated that the processor 118 and the transceiver
120 may be integrated together in an electronic package or
chip.
[0047] The transmit/receive element 122 may be configured to
transmit signals to, or receive signals from, a base station (e.g.,
the base station 114a) over the air interface 116. For example, in
one embodiment, the transmit/receive element 122 may be an antenna
configured to transmit and/or receive RF signals. In an embodiment,
the transmit/receive element 122 may be an emitter/detector
configured to transmit and/or receive IR, UV, or visible light
signals, for example. In yet another embodiment, the
transmit/receive element 122 may be configured to transmit and/or
receive both RF and light signals. It will be appreciated that the
transmit/receive element 122 may be configured to transmit and/or
receive any combination of wireless signals.
[0048] Although the transmit/receive element 122 is depicted in
FIG. 1B as a single element, the WTRU 102 may include any number of
transmit/receive elements 122. More specifically, the WTRU 102 may
employ MIMO technology. Thus, in one embodiment, the WTRU 102 may
include two or more transmit/receive elements 122 (e.g., multiple
antennas) for transmitting and receiving wireless signals over the
air interface 116.
[0049] The transceiver 120 may be configured to modulate the
signals that are to be transmitted by the transmit/receive element
122 and to demodulate the signals that are received by the
transmit/receive element 122. As noted above, the WTRU 102 may have
multi-mode capabilities. Thus, the transceiver 120 may include
multiple transceivers for enabling the WTRU 102 to communicate via
multiple RATs, such as NR and IEEE 802.11, for example.
[0050] The processor 118 of the WTRU 102 may be coupled to, and may
receive user input data from, the speaker/microphone 124, the
keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal
display (LCD) display unit or organic light-emitting diode (OLED)
display unit). The processor 118 may also output user data to the
speaker/microphone 124, the keypad 126, and/or the display/touchpad
128. In addition, the processor 118 may access information from,
and store data in, any type of suitable memory, such as the
non-removable memory 130 and/or the removable memory 132. The
non-removable memory 130 may include random-access memory (RAM),
read-only memory (ROM), a hard disk, or any other type of memory
storage device. The removable memory 132 may include a subscriber
identity module (SIM) card, a memory stick, a secure digital (SD)
memory card, and the like. In other embodiments, the processor 118
may access information from, and store data in, memory that is not
physically located on the WTRU 102, such as on a server or a home
computer (not shown).
[0051] The processor 118 may receive power from the power source
134, and may be configured to distribute and/or control the power
to the other components in the WTRU 102. The power source 134 may
be any suitable device for powering the WTRU 102. For example, the
power source 134 may include one or more dry cell batteries (e.g.,
nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride
(NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and
the like.
[0052] The processor 118 may also be coupled to the GPS chipset
136, which may be configured to provide location information (e.g.,
longitude and latitude) regarding the current location of the WTRU
102. In addition to, or in lieu of, the information from the GPS
chipset 136, the WTRU 102 may receive location information over the
air interface 116 from a base station (e.g., base stations 114a,
114b) and/or determine its location based on the timing of the
signals being received from two or more nearby base stations. It
will be appreciated that the WTRU 102 may acquire location
information by way of any suitable location-determination method
while remaining consistent with an embodiment.
[0053] The processor 118 may further be coupled to other
peripherals 138, which may include one or more software and/or
hardware modules that provide additional features, functionality
and/or wired or wireless connectivity. For example, the peripherals
138 may include an accelerometer, an e-compass, a satellite
transceiver, a digital camera (for photographs and/or video), a
universal serial bus (USB) port, a vibration device, a television
transceiver, a hands free headset, a Bluetooth.RTM. module, a
frequency modulated (FM) radio unit, a digital music player, a
media player, a video game player module, an Internet browser, a
Virtual Reality and/or Augmented Reality (VR/AR) device, an
activity tracker, and the like. The peripherals 138 may include one
or more sensors, the sensors may be one or more of a gyroscope, an
accelerometer, a hall effect sensor, a magnetometer, an orientation
sensor, a proximity sensor, a temperature sensor, a time sensor, a
geolocation sensor; an altimeter, a light sensor, a touch sensor, a
magnetometer, a barometer, a gesture sensor, a biometric sensor,
and/or a humidity sensor.
[0054] The WTRU 102 may include a full duplex radio for which
transmission and reception of some or all of the signals (e.g.,
associated with particular subframes for both the UL (e.g., for
transmission) and downlink (e.g., for reception) may be concurrent
and/or simultaneous. The full duplex radio may include an
interference management unit to reduce and or substantially
eliminate self-interference via either hardware (e.g., a choke) or
signal processing via a processor (e.g., a separate processor (not
shown) or via processor 118). In an embodiment, the WRTU 102 may
include a half-duplex radio for which transmission and reception of
some or all of the signals (e.g., associated with particular
subframes for either the UL (e.g., for transmission) or the
downlink (e.g., for reception).
[0055] FIG. 10 is a system diagram illustrating the RAN 104 and the
CN 106 according to an embodiment. As noted above, the RAN 104 may
employ an E-UTRA radio technology to communicate with the WTRUs
102a, 102b, 102c over the air interface 116. The RAN 104 may also
be in communication with the CN 106.
[0056] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it
will be appreciated that the RAN 104 may include any number of
eNode-Bs while remaining consistent with an embodiment. The
eNode-Bs 160a, 160b, 160c may each include one or more transceivers
for communicating with the WTRUs 102a, 102b, 102c over the air
interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may
implement MIMO technology. Thus, the eNode-B 160a, for example, may
use multiple antennas to transmit wireless signals to, and/or
receive wireless signals from, the WTRU 102a.
[0057] Each of the eNode-Bs 160a, 160b, 160c may be associated with
a particular cell (not shown) and may be configured to handle radio
resource management decisions, handover decisions, scheduling of
users in the UL and/or DL, and the like. As shown in FIG. 10, the
eNode-Bs 160a, 160b, 160c may communicate with one another over an
X2 interface.
[0058] The CN 106 shown in FIG. 10 may include a mobility
management entity (MME) 162, a serving gateway (SGW) 164, and a
packet data network (PDN) gateway (or PGW) 166. While each of the
foregoing elements are depicted as part of the CN 106, it will be
appreciated that any of these elements may be owned and/or operated
by an entity other than the CN operator.
[0059] The MME 162 may be connected to each of the eNode-Bs 162a,
162b, 162c in the RAN 104 via an S1 interface and may serve as a
control node. For example, the MME 162 may be responsible for
authenticating users of the WTRUs 102a, 102b, 102c, bearer
activation/deactivation, selecting a particular serving gateway
during an initial attach of the WTRUs 102a, 102b, 102c, and the
like. The MME 162 may provide a control plane function for
switching between the RAN 104 and other RANs (not shown) that
employ other radio technologies, such as GSM and/or WCDMA.
[0060] The SGW 164 may be connected to each of the eNode Bs 160a,
160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may
generally route and forward user data packets to/from the WTRUs
102a, 102b, 102c. The SGW 164 may perform other functions, such as
anchoring user planes during inter-eNode B handovers, triggering
paging when DL data is available for the WTRUs 102a, 102b, 102c,
managing and storing contexts of the WTRUs 102a, 102b, 102c, and
the like.
[0061] The SGW 164 may be connected to the PGW 166, which may
provide the WTRUs 102a, 102b, 102c with access to packet-switched
networks, such as the Internet 110, to facilitate communications
between the WTRUs 102a, 102b, 102c and IP-enabled devices.
[0062] The CN 106 may facilitate communications with other
networks. For example, the CN 106 may provide the WTRUs 102a, 102b,
102c with access to circuit-switched networks, such as the PSTN
108, to facilitate communications between the WTRUs 102a, 102b,
102c and traditional land-line communications devices. For example,
the CN 106 may include, or may communicate with, an IP gateway
(e.g., an IP multimedia subsystem (IMS) server) that serves as an
interface between the CN 106 and the PSTN 108. In addition, the CN
106 may provide the WTRUs 102a, 102b, 102c with access to the other
networks 112, which may include other wired and/or wireless
networks that are owned and/or operated by other service
providers.
[0063] Although the WTRU is described in FIGS. 1A-1D as a wireless
terminal, it is contemplated that in certain representative
embodiments that such a terminal may use (e.g., temporarily or
permanently) wired communication interfaces with the communication
network.
[0064] In representative embodiments, the other network 112 may be
a WLAN.
[0065] A WLAN in Infrastructure Basic Service Set (BSS) mode may
have an Access Point (AP) for the BSS and one or more stations
(STAs) associated with the AP. The AP may have an access or an
interface to a Distribution System (DS) or another type of
wired/wireless network that carries traffic in to and/or out of the
BSS. Traffic to STAs that originates from outside the BSS may
arrive through the AP and may be delivered to the STAs. Traffic
originating from STAs to destinations outside the BSS may be sent
to the AP to be delivered to respective destinations. Traffic
between STAs within the BSS may be sent through the AP, for
example, where the source STA may send traffic to the AP and the AP
may deliver the traffic to the destination STA. The traffic between
STAs within a BSS may be considered and/or referred to as
peer-to-peer traffic. The peer-to-peer traffic may be sent between
(e.g., directly between) the source and destination STAs with a
direct link setup (DLS). In certain representative embodiments, the
DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A
WLAN using an Independent BSS (IBSS) mode may not have an AP, and
the STAs (e.g., all of the STAs) within or using the IBSS may
communicate directly with each other. The IBSS mode of
communication may sometimes be referred to herein as an "ad-hoc"
mode of communication.
[0066] When using the 802.11ac infrastructure mode of operation or
a similar mode of operations, the AP may transmit a beacon on a
fixed channel, such as a primary channel. The primary channel may
be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set
width via signaling. The primary channel may be the operating
channel of the BSS and may be used by the STAs to establish a
connection with the AP. In certain representative embodiments,
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
may be implemented, for example in in 802.11 systems. For CSMA/CA,
the STAs (e.g., every STA), including the AP, may sense the primary
channel. If the primary channel is sensed/detected and/or
determined to be busy by a particular STA, the particular STA may
back off. One STA (e.g., only one station) may transmit at any
given time in a given BSS.
[0067] High Throughput (HT) STAs may use a 40 MHz wide channel for
communication, for example, via a combination of the primary 20 MHz
channel with an adjacent or nonadjacent 20 MHz channel to form a 40
MHz wide channel.
[0068] Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz,
80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz,
channels may be formed by combining contiguous 20 MHz channels. A
160 MHz channel may be formed by combining 8 contiguous 20 MHz
channels, or by combining two non-contiguous 80 MHz channels, which
may be referred to as an 80+80 configuration. For the 80+80
configuration, the data, after channel encoding, may be passed
through a segment parser that may divide the data into two streams.
Inverse Fast Fourier Transform (IFFT) processing, and time domain
processing, may be done on each stream separately. The streams may
be mapped on to the two 80 MHz channels, and the data may be
transmitted by a transmitting STA. At the receiver of the receiving
STA, the above described operation for the 80+80 configuration may
be reversed, and the combined data may be sent to the Medium Access
Control (MAC).
[0069] Sub 1 GHz modes of operation are supported by 802.11af and
802.11ah. The channel operating bandwidths, and carriers, are
reduced in 802.11af and 802.11ah relative to those used in 802.11n,
and 802.11ac. 802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths
in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz,
2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum.
According to a representative embodiment, 802.11ah may support
Meter Type Control/Machine-Type Communications, such as MTC devices
in a macro coverage area. MTC devices may have certain
capabilities, for example, limited capabilities including support
for (e.g., only support for) certain and/or limited bandwidths. The
MTC devices may include a battery with a battery life above a
threshold (e.g., to maintain a very long battery life).
[0070] WLAN systems, which may support multiple channels, and
channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and
802.11ah, include a channel which may be designated as the primary
channel. The primary channel may have a bandwidth equal to the
largest common operating bandwidth supported by all STAs in the
BSS. The bandwidth of the primary channel may be set and/or limited
by a STA, from among all STAs in operating in a BSS, which supports
the smallest bandwidth operating mode. In the example of 802.11ah,
the primary channel may be 1 MHz wide for STAs (e.g., MTC type
devices) that support (e.g., only support) a 1 MHz mode, even if
the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16
MHz, and/or other channel bandwidth operating modes. Carrier
sensing and/or Network Allocation Vector (NAV) settings may depend
on the status of the primary channel. If the primary channel is
busy, for example, due to a STA (which supports only a 1 MHz
operating mode), transmitting to the AP, the entire available
frequency bands may be considered busy even though a majority of
the frequency bands remains idle and may be available.
[0071] In the United States, the available frequency bands, which
may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the
available frequency bands are from 917.5 MHz to 923.5 MHz. In
Japan, the available frequency bands are from 916.5 MHz to 927.5
MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz
depending on the country code.
[0072] FIG. 1D is a system diagram illustrating the RAN 113 and the
CN 115 according to an embodiment. As noted above, the RAN 113 may
employ an NR radio technology to communicate with the WTRUs 102a,
102b, 102c over the air interface 116. The RAN 113 may also be in
communication with the CN 115.
[0073] The RAN 113 may include gNBs 180a, 180b, 180c, though it
will be appreciated that the RAN 113 may include any number of gNBs
while remaining consistent with an embodiment. The gNBs 180a, 180b,
180c may each include one or more transceivers for communicating
with the WTRUs 102a, 102b, 102c over the air interface 116. In one
embodiment, the gNBs 180a, 180b, 180c may implement MIMO
technology. For example, gNBs 180a, 108b may utilize beamforming to
transmit signals to and/or receive signals from the gNBs 180a,
180b, 180c. Thus, the gNB 180a, for example, may use multiple
antennas to transmit wireless signals to, and/or receive wireless
signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b,
180c may implement carrier aggregation technology. For example, the
gNB 180a may transmit multiple component carriers to the WTRU 102a
(not shown). A subset of these component carriers may be on
unlicensed spectrum while the remaining component carriers may be
on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c
may implement Coordinated Multi-Point (CoMP) technology. For
example, WTRU 102a may receive coordinated transmissions from gNB
180a and gNB 180b (and/or gNB 180c).
[0074] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a,
180b, 180c using transmissions associated with a scalable
numerology. For example, the OFDM symbol spacing and/or OFDM
subcarrier spacing may vary for different transmissions, different
cells, and/or different portions of the wireless transmission
spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs
180a, 180b, 180c using subframe or transmission time intervals
(TTIs) of various or scalable lengths (e.g., containing varying
number of OFDM symbols and/or lasting varying lengths of absolute
time).
[0075] The gNBs 180a, 180b, 180c may be configured to communicate
with the WTRUs 102a, 102b, 102c in a standalone configuration
and/or a non-standalone configuration. In the standalone
configuration, WTRUs 102a, 102b, 102c may communicate with gNBs
180a, 180b, 180c without also accessing other RANs (e.g., such as
eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs
102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c
as a mobility anchor point. In the standalone configuration, WTRUs
102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using
signals in an unlicensed band. In a non-standalone configuration
WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a,
180b, 180c while also communicating with/connecting to another RAN
such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b,
102c may implement DC principles to communicate with one or more
gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c
substantially simultaneously. In the non-standalone configuration,
eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs
102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional
coverage and/or throughput for servicing WTRUs 102a, 102b,
102c.
[0076] Each of the gNBs 180a, 180b, 180c may be associated with a
particular cell (not shown) and may be configured to handle radio
resource management decisions, handover decisions, scheduling of
users in the UL and/or DL, support of network slicing, dual
connectivity, interworking between NR and E-UTRA, routing of user
plane data towards User Plane Function (UPF) 184a, 184b, routing of
control plane information towards Access and Mobility Management
Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the
gNBs 180a, 180b, 180c may communicate with one another over an Xn
interface.
[0077] The CN 115 shown in FIG. 1D may include at least one AMF
182a, 182b, at least one UPF 184a, 184b, at least one Session
Management Function (SMF) 183a, 183b, and possibly a Data Network
(DN) 185a, 185b. While each of the foregoing elements are depicted
as part of the CN 115, it will be appreciated that any of these
elements may be owned and/or operated by an entity other than the
CN operator.
[0078] The AMF 182a, 182b may be connected to one or more of the
gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may
serve as a control node. For example, the AMF 182a, 182b may be
responsible for authenticating users of the WTRUs 102a, 102b, 102c,
support for network slicing (e.g., handling of different PDU
sessions with different requirements), selecting a particular SMF
183a, 183b, management of the registration area, termination of NAS
signaling, mobility management, and the like. Network slicing may
be used by the AMF 182a, 182b in order to customize CN support for
WTRUs 102a, 102b, 102c based on the types of services being
utilized WTRUs 102a, 102b, 102c. For example, different network
slices may be established for different use cases such as services
relying on ultra-reliable low latency (URLLC) access, services
relying on enhanced massive mobile broadband (eMBB) access,
services for machine type communication (MTC) access, and/or the
like. The AMF 162 may provide a control plane function for
switching between the RAN 113 and other RANs (not shown) that
employ other radio technologies, such as LTE, LTE-A, LTE-A Pro,
and/or non-3GPP access technologies such as WiFi.
[0079] The SMF 183a, 183b may be connected to an AMF 182a, 182b in
the CN 115 via an N11 interface. The SMF 183a, 183b may also be
connected to a UPF 184a, 184b in the CN 115 via an N4 interface.
The SMF 183a, 183b may select and control the UPF 184a, 184b and
configure the routing of traffic through the UPF 184a, 184b. The
SMF 183a, 183b may perform other functions, such as managing and
allocating WTRU IP address, managing PDU sessions, controlling
policy enforcement and QoS, providing downlink data notifications,
and the like. A PDU session type may be IP-based, non-IP based,
Ethernet-based, and the like.
[0080] The UPF 184a, 184b may be connected to one or more of the
gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may
provide the WTRUs 102a, 102b, 102c with access to packet-switched
networks, such as the Internet 110, to facilitate communications
between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF
184, 184b may perform other functions, such as routing and
forwarding packets, enforcing user plane policies, supporting
multi-homed PDU sessions, handling user plane QoS, buffering
downlink packets, providing mobility anchoring, and the like.
[0081] The CN 115 may facilitate communications with other
networks. For example, the CN 115 may include, or may communicate
with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server)
that serves as an interface between the CN 115 and the PSTN 108. In
addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with
access to the other networks 112, which may include other wired
and/or wireless networks that are owned and/or operated by other
service providers. In one embodiment, the WTRUs 102a, 102b, 102c
may be connected to a local Data Network (DN) 185a, 185b through
the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and
an N6 interface between the UPF 184a, 184b and the DN 185a,
185b.
[0082] In view of FIGS. 1A-1D, and the corresponding description of
FIGS. 1A-1D, one or more, or all, of the functions described herein
with regard to one or more of: WTRU 102a-d, Base Station 114a-b,
eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b,
UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s)
described herein, may be performed by one or more emulation devices
(not shown). The emulation devices may be one or more devices
configured to emulate one or more, or all, of the functions
described herein. For example, the emulation devices may be used to
test other devices and/or to simulate network and/or WTRU
functions.
[0083] The emulation devices may be designed to implement one or
more tests of other devices in a lab environment and/or in an
operator network environment. For example, the one or more
emulation devices may perform the one or more, or all, functions
while being fully or partially implemented and/or deployed as part
of a wired and/or wireless communication network in order to test
other devices within the communication network. The one or more
emulation devices may perform the one or more, or all, functions
while being temporarily implemented/deployed as part of a wired
and/or wireless communication network. The emulation device may be
directly coupled to another device for purposes of testing and/or
may performing testing using over-the-air wireless
communications.
[0084] The one or more emulation devices may perform the one or
more, including all, functions while not being implemented/deployed
as part of a wired and/or wireless communication network. For
example, the emulation devices may be utilized in a testing
scenario in a testing laboratory and/or a non-deployed (e.g.,
testing) wired and/or wireless communication network in order to
implement testing of one or more components. The one or more
emulation devices may be test equipment. Direct RF coupling and/or
wireless communications via RF circuitry (e.g., which may include
one or more antennas) may be used by the emulation devices to
transmit and/or receive data.
[0085] For load-based systems (e.g., systems where the
transmit/receive structures may not be fixed in time),
Listen-Before-Talk (LBT) may be characterized by a number, N, which
may correspond to the number of clear idle slots in an extended
Clear Channel Assessment (CCA) (e.g., instead of and/or in addition
to corresponding to a fixed frame period). For example, N may be
randomly selected from a range.
[0086] A WTRU may be configured to operate in multiple types of
radio access deployments described herein. A WTRU may be configured
to implement a standalone operation (e.g., a variant standalone
operation). For example, a WTRU may be configured to implement a
variant of standalone New Radio (NR)-based operation. A WTRU may be
configured to implement a variant of dual connectivity (DC)
operations. For example, a variant of DC operations may include a
dual connectivity (EN-DC) with one or more carriers operating
according to the LTE radio access technology (RAT) (e.g., with a
connectivity corresponding to an NR RAT). A WTRU may be configured
to implement a NR DC with at least two sets of one or more carriers
operating according to the NR RAT. A WTRU may be configured to
implement different variations of carrier aggregation (CA). For
example, CA may include different combinations of zero or more
carriers of each of LTE and NR RATs.
[0087] One or more of the following functionalities may be utilized
for LTE license assisted access (LAA) systems. LBT/CCA
functionalities may be utilized for LAA systems. Discontinuous
transmission on a carrier with limited maximum transmission
duration functionality may be utilized for LAA systems. Carrier
selection functionality may be utilized for LAA systems. Transmit
power control functionality may be utilized for LAA systems.
[0088] LBT and/or CM may be performed by a WTRU in LAA systems. A
WTRU may use LBT to perform a CCA check. For example, a WTRU may
use LBT to perform a CCA check before using a channel. The CCA may
use energy detection to determine the presence or absence of other
signals on a channel, which may indicate that a channel is either
occupied or clear, respectively. Regulations may define the usage
of LBT in unlicensed bands. Apart from regulatory requirements,
carrier sensing via LBT may provide for equitable sharing of the
unlicensed spectrum and/or may be considered a large-scale
framework (e.g., a single global solution framework) for operation
in the unlicensed.
[0089] Discontinuous transmission (DTX) may limit the maximum
transmission duration and DTX may be performed on a carrier. In
unlicensed spectrum, channel availability may not be guaranteed.
Certain regions (e.g., Europe and/or Japan) may not allow for
continuous transmission and/or may impose limits on transmissions
(e.g., limits on the maximum duration of a transmission burst) in
an unlicensed spectrum. DTX may limit the maximum transmission
duration and may be performed in LM systems.
[0090] Carrier selection may be performed by LAA nodes such that
carriers with low interference are selected. If, for example, the
bandwidth available for unlicensed spectrum is large, carrier
selection may allow for LAA nodes to select the carriers with low
interference and/or may allow for co-existence with other
unlicensed spectrum deployments.
[0091] A Transmit Power Control (TPC) may be regulated in some
regions. For example, a transmitting device (e.g., WTRU) may be
regulated such that the transmit power is proportionally reduced
(e.g., reduced by 3 dB or 6 dB) when compared to the maximum
nominal transmit power.
[0092] Radio resource management (RRM) measurements, which may
include cell identification, may enable mobility between secondary
cells (SCells) and/or may allow for robust operation in the
unlicensed band.
[0093] Channel-state information (CSI) measurements, which may
include channel and/or interference measurements, may be performed
by a WTRU. For example, a WTRU operating in an unlicensed carrier
may support frequency/time estimation and/or synchronization. If a
WTRU supports frequency/time estimation and/or synchronization, RRM
measurements may be enabled and/or the reception of information on
the unlicensed band may be successful.
[0094] A WTRU (e.g., a WTRU in NR) may operate using bandwidth
parts (BWPs) in a carrier. For example, the WTRU may access the
cell using an initial BWP. The WTRU may be configured (e.g., may
then be configured) with a set of BWPs to continue operation. The
WTRU may have an active BWP. For example, the WTRU may have an
active BWP at any given moment. A BWP (e.g., each BWP) may be
configured with one or more (e.g., a set of) control resource sets
(CORESETs) within which a WTRU may blind decode physical downlink
control channel (PDCCH) candidates (e.g., for scheduling
information, among other things).
[0095] A wireless communication system(s) (e.g., NR) may support
variable transmission durations and/or feedback timing. For
example, if a wireless communication system supports variable
transmission durations, a physical downlink shared channel (PDSCH)
and/or a physical uplink shared channel (PUSCH) transmission may
occupy a subset of symbols (e.g., a contiguous subset of symbols)
within a slot. For example, if a wireless communication system
supports variable feedback timing, the DCI for a downlink (DL)
assignment may include an indication for the timing of the feedback
for the WTRU. For example, the DCI may indicate a specific PUCCH
resource to be used for the feedback.
[0096] A wireless communication system(s) (e.g., a NR communication
system) may support one or more types of (e.g., two types of) PUCCH
resources. For example, a wireless communication system (e.g., a NR
communication system) may support PUCCH (e.g., a short PUCCH and/or
a long PUCCH). The short PUCCH may be transmitted using 1 or 2 OFDM
symbols, while the long PUCCH may be transmitted using up to 14
OFDM symbols. Each PUCCH type may use one or more formats (e.g.,
multiple formats). For example, the format used may be based on the
type and/or size of corresponding payload.
[0097] In a wireless communication system(s) (e.g., a NR
communication system), discontinuous reception (DRX) may be used to
reduce WTRU power consumption. For example, when a WTRU is in
connected mode DRX, the WTRU may be configured with a DRX cycle.
When the WTRU is in the DRX cycle, the WTRU may monitor the PDCCH
for a subset of time instances, and during the remaining time
instances, the WTRU may sleep (e.g., may not monitor) with the
receiver circuitry switched off. A WTRU may receive scheduling
information in its PDCCH during a monitoring portion of the cycle.
Upon receiving the scheduling information, the WTRU may continue to
monitor the PDCCH. For example, the WTRU may continue to monitor
the PDCCH for further scheduling information. The WTRU may return
to the sleep period after some period of inactivity when no PDCCH
transmission scheduling additional new data have been received.
[0098] The sleep duration may be proportional (e.g., directly
proportional) to the power savings. For example, the longer the
sleep duration, the larger the reduction in WTRU power consumption.
One or more scheduling restrictions may apply and/or may affect
efficiency.
[0099] A WTRU may be in an IDLE mode. When a WTRU is in an IDLE
mode, the WTRU may be configured with a DRX cycle. A WTRU may
monitor for paging information. Upon receiving the paging
information, a DRX cycle may allow for reduced power consumption of
the WTRU. A WTRU may wake up from a paging occasion (PO). The WTRU
may determine whether the WTRU has been paged. Upon waking up from
a PO and determining that the WTRU has not been paged, the WTRU may
return to sleep.
[0100] One or more operational techniques (e.g., NR-based
operational techniques) may include initial access,
scheduling/HARQ, and/or mobility. The one or more operational
techniques (e.g., NR-based operational techniques) may be used in
an unlicensed spectrum and/or for coexistence with LTE-LAA and
other RATs. Operational techniques may include NR-based LAA cell
connection with an LTE or NR anchor cell and/or NR-based cells
standalone operation in an unlicensed spectrum.
[0101] Transmissions in an unlicensed spectrum (e.g., NR
transmissions in an unlicensed spectrum) may be preceded by a
channel acquisition. For example, a successful LBT may be performed
before a network transmits PDCCH information for a data
transmission, paging indications, and/or system information
transmissions. To reduce power consumption, a WTRU may not
continually monitor a PDCCH. For example, to reduce power
consumption, a WTRU may not monitor PDCCHs at all times.
[0102] A WTRU may enter a low activity mode where the WTRU may
monitor fewer PDCCH occasions and reduce power consumption. Upon
entering a low activity mode, the WTRU may differentiate between
when the WTRU was not reached on purpose (e.g., the network did not
have a transmission for the WTRU) and when the WTRU was not reached
due to lack of channel acquisition by the network (e.g., despite
having a transmission for the WTRU). If, for example, the WTRU
behaves similarly (e.g., the same) in both scenarios, latency may
become prohibitive and/or a serviceable WTRU (e.g., a reachable
WTRU) may consume a considerable amount of power. One or more
implementations may attempt to balance WTRU reachability having an
appropriate level of latency with WTRU power savings.
[0103] As described herein, an awake state may be or may include a
state where a WTRU monitors one or more control channels (e.g.,
PDCCH, CORESET, and/or search space). An awake state may correspond
to certain periods of time. For example, an awake period may
correspond to times when one or more of the ON duration timers,
inactivity timers, and/or retransmission timers are active or
running. As described herein, a sleep state may be or may include
time (e.g., any time) during a DRX cycle where a WTRU is not in an
awake state. For example, the time when a WTRU is not expected to
monitor one or more control channels may be a sleep state. In
examples, a timer for a sleep state may be used to determine the
duration of the sleep state in an absolute manner. In examples, a
timer for a sleep state may be used to indicate the time between
the starting points of two consecutive awake states.
[0104] DRX may be performed for transmission using an unlicensed
spectrum. A WTRU may be configured with a DRX pattern, which may
determine an activity state of the WTRU. An activity state may be
characterized by one or more of a set of PDCCH monitoring occasions
(e.g., and/or control resource sets (CORESETs)), a set of one or
more BWPs to monitor, and/or a set of downlink control information
(DCI) formats used for blind detection. For example, a WTRU may be
configured with an awake state. When the WTRU is in an awake state,
the WTRU may be configured with one or more (e.g., multiple) PDCCH
monitoring occasions (e.g., in multiple CORESETs). The PDCCH
monitoring occasion may occur within a slot, for multiple BWPs,
and/or for one or more DCI formats (e.g., multiple DCI formats).
The WTRU may be configured with a sleep state/lower activity state.
When the WTRU is in a sleep state/lower activity state, the WTRU
may be configured with fewer PDCCH monitoring occasions having a
larger periodicity. For example, the WTRU may be configured with
fewer PDCCH monitoring occasions than that of the awake state or no
PDCCH monitoring occasions. The PDCCH monitoring occasions may
occur for a BWP (e.g., a single BWP) and for fewer DCI formats. For
example, the PDCCH monitoring occasions may occur fewer than that
of the awake state.
[0105] A WTRU may be configured with a timer, which may be used to
switch states. The timer may terminate. Upon termination of the
timer, the WTRU may toggle from one state to another. Depending on
the state, the WTRU may trigger (e.g., or reset) the timer based on
receiving a transmission from a gNB or based on the time at which
it entered the state. For example, when a WTRU is in a low activity
state (e.g., or sleep state), the WTRU may reset the timer upon
entering that state. Upon expiration of the timer, the WTRU may
enter a higher activity state (e.g., or awake state). A WTRU may
use one or more of the following to determine when to trigger/start
a timer, and possibly how to determine the value of the timer
(e.g., for toggling back to the sleep state). A WTRU may use
reception of a DCI for the WTRU for determining a trigger/start
timer and/or the value of the timer. A WTRU may use reception of a
DCI in a common search space for determining a trigger/start timer
and/or the value of the timer. A WTRU may use reception of a
reference signal (RS) for determining a trigger/start timer and/or
the value of the timer. A WTRU may use reception of a preamble for
determining a trigger/start timer and/or the value of the timer. A
WTRU may use reception of a go-to sleep signal for determining a
trigger/start timer and/or the value of the timer. A WTRU may
determine triggering/starting a timer and/or the value of the timer
based on when the WTRU entered the awake time.
[0106] One or more of the following may apply when a WTRU receives
DCI. For example, when a WTRU receives DCI using a WTRU-specific
radio network temporary identifier (RNTI), the WTRU may
reset/restart the timer to a value (e.g., a first value). A WTRU
may be configured with a timer value(s). For example, a WTRU may be
configured with two timer values. A first timer value may be a
(relatively) long timer value and a second value may be a
(relatively) short timer value. The WTRU may receive a DCI using a
WTRU-specific RNTI. When the WTRU receives a DCI using a
WTRU-specific RNTI, the WTRU may reset the timer to the first value
(e.g., the long timer value). When the WTRU does not receive a DCI
using a WTRU-specific RNTI, the WTRU may reset the timer to the
second time value (e.g., short timer value).
[0107] One or more of the following may apply when a WTRU receives
DCI via a common search space. For example, upon reception of the
DCI in the common search space, the WTRU may reset/restart the
timer to a value (e.g., a first value). The timer value used may be
based on the type of indication (e.g., WTRU-specific DCI and/or
common search space DCI). The timer value selection may be similar
(e.g., the same) as DCI using WTRU-specific RNTI described herein.
For example, the DCI may be decoded using a RNTI used to determine
channel acquisition, such as a channel occupancy RNTI. The DCI may
indicate that a channel has been successfully acquired. The WTRU
may determine to go back to sleep (e.g., more rapidly) based on a
decoded DCI transmission for channel acquisition and/or the lack of
a scheduling DCI. The DCI may use a WTRU-specific RNTI and/or
common RNTI to schedule uplink and/or downlink transmissions
applicable to the WTRU.
[0108] One or more of the following may apply when a WTRU receives
a RS. For example, upon reception of a discovery RS (DRS) or a
component thereof (e.g., synchronization signal block (SSB)), a
WTRU may reset/restart a timer to a value (e.g., a first value as
described above).
[0109] One or more of the following may apply when a WTRU receives
a preamble. For example, a WTRU may receive a preamble (e.g., a
non-scheduling preamble), which may indicate that the channel was
acquired. Upon reception of the preamble, the WTRU may
reset/restart a timer to a value (e.g., a first value as described
above).
[0110] One or more of the following may apply when a WTRU receives
a go-to sleep signal. For example, upon reception of a signal
indicating for the WTRU to go-to sleep, the WTRU may go to a sleep
state (e.g., may immediately go to a sleep state).
[0111] One or more of the following may apply when the WTRU
determines when to trigger/start a timer, and possibly how to
determine the value of the timer (e.g., for toggling back to the
sleep state) based on when the WTRU entered the awake time. Upon
entering the awake state, the WTRU may set a timer to a timer value
(e.g., a first timer value). The timer may be associated with an
amount of time that the WTRU remains in an active/awake state. For
example, the timer may be associated with an amount of time that
the WTRU remains in an active/awake state assuming the WTRU is not
later triggered to change the value, re-start the timer, etc. based
on later observed events or transmissions.
[0112] A WTRU in the awake state (e.g., or the ON duration of a DRX
cycle) may monitor one or more channels. The WTRU may attempt to
receive one or more of the signals and/or transmissions described
herein during the awake state. Upon reception of such a
transmission from a serving cell, a WTRU may determine that the
channel was acquired (e.g., successfully acquired) by its serving
cell during its ON duration. The WTRU may assume (e.g., may then
assume) that a lack of any other transmissions intended to assign
DL resources for the WTRU means that the WTRU may return to sleep
and/or may proceed with the DRX cycle.
[0113] One or more of the following may occur when the WTRU
receives a transmission from its serving cell during its ON
duration. For example, the WTRU may receive a transmission other
than a scheduling assignment from the serving cell during its ON
duration. The WTRU may receive a transmission, and the WTRU may be
in a DRX cycle, such as a short DRX cycle or a long DRX cycle. Upon
receiving a transmission and currently being in a short DRX cycle,
the WTRU may continue to be in the short DRX cycle or the WTRU may
switch to a long DRX cycle. For example, upon receiving a
transmission and currently being in a short DRX cycle, the WTRU may
continue to be in the short DRX cycle until expiration of a timer.
Upon receiving a transmission and currently being in a long DRX
cycle, the WTRU may continue to be in the long DRX cycle. Upon
receiving a transmission and currently not being in a DRX cycle,
the WTRU may continue the inactivity timer and/or trigger the
inactivity timer to determine when to enter a DRX cycle.
[0114] The WTRU may not receive a transmission from a serving cell,
and the WTRU may be in a DRX cycle, such as a short DRX cycle or a
long DRX cycle. If the WTRU does not receive a transmission from
the serving cell during its ON duration, one or more of the
following may occur. If the WTRU does not receive a transmission
and the WTRU is currently in a short DRX cycle, the WTRU may
continue the short DRX cycle and/or may restart/pause the short DRX
cycle timer. If the WTRU does not receive a transmission and the
WTRU is currently in a long DRX cycle, the WTRU may return to the
short DRX cycle and/or may start the short DRX cycle timer. If the
WTRU does not receive a transmission, the WTRU may begin a new DRX
cycle (e.g., shorter than short DRX cycle) and/or start a new DRX
cycle timer (e.g., having shorter duration than short DRX cycle
timer).
[0115] If the WTRU does not receive a transmission from its serving
cell during its ON duration and if the WTRU is currently in a short
DRX cycle, the WTRU may continue the short DRX cycle and/or may
restart/pause the short DRX cycle timer. If the short DRX cycle
timer is paused, the timer may be resumed upon the WTRU receiving a
transmission from the serving cell during an ON duration. For
example, the timer may be resumed when the WTRU receives a
transmission other than a transmission with a scheduling assignment
for the WTRU.
[0116] The WTRU may return to a short DRX cycle and/or may start
the short DRX cycle timer. If the WTRU does not receive a
transmission from its serving cell during its ON duration and if
the WTRU is currently in a long DRX cycle, the WTRU may return to a
short DRX cycle and/or may start the short DRX cycle timer. In
examples, the WTRU may enter a short DRX cycle and/or may remain in
the short DRX cycle until reception of a transmission from the
serving cell (e.g., other than a transmission with a scheduling
assignment for the WTRU). Upon reception of such a transmission,
the WTRU may return (e.g., immediately return) to the long DRX
cycle.
[0117] The WTRU may begin a new DRX cycle with a new DRX cycle
timer. For example, the new DRX cycle may be shorter than a short
DRX cycle, and the new DRX cycle timer may have shorter duration
than a short DRX cycle timer. If the WTRU does not receive a
transmission from its serving cell during its ON duration, the WTRU
may begin a new DRX cycle and/or may start a new DRX cycle timer.
The new DRX cycle and/or the new DRX cycle timer may be used to
determine/declare radio link failure (RLF) condition. Upon
reception of a transmission during an ON duration of the new DRX
cycle, the WTRU may stop and/or cancel the new DRX timer and may
enter a regular DRX cycle (e.g., short or long DRX cycle). For
example, if the WTRU was in a short/long DRX cycle prior to
entering the new DRX cycle, the WTRU may return to the short/long
DRX cycle, respectively. While in the new DRX cycle, the WTRU may
pause another ongoing DRX cycle, such as the short and/or the long
DRX cycle timer(s) (e.g., if configured and/or active). Upon
expiration of the new DRX cycle timer, the WTRU may declare
RLF.
[0118] A WTRU may determine that a channel is being used or is
otherwise occupied. For example, a WTRU may determine the channel
is being occupied due to a transmission associated with the cell of
the WTRU or by an interfering cell. Such a determination may enable
the WTRU to determine whether the WTRU is reachable by the cell for
transmission of signals/channels during an awake period. For
example, a WTRU may determine that the channel occupancy during an
awake period is above or below a certain threshold. The WTRU may
determine the channel occupancy based on interference measurements
on the channel. In examples, the occupancy may be determined in
terms of an interference measurement being above or below a
threshold. The interference measurement may be performed in one or
more time instances. In examples, the channel occupancy may be
determined based on the number of instances that the interference
on a channel is above or below a certain threshold.
[0119] When a WTRU determines that a channel is occupied, the WTRU
may determine whether to trigger or reset a timer (e.g., along with
the value of the timer). For example, if a channel is determined
not to be occupied during an awake state and the WTRU does not
receive a signal from the network, the WTRU may assume that the
network does not have a traffic to transmit to the WTRU. As such,
the WTRU may trigger a first timer (e.g., which may be a short
timer) based on the last received transmission and/or based on the
time the WTRU entered an awake state. The WTRU may change states
and/or go to sleep when the timer expires.
[0120] In examples, if a WTRU observes high channel occupancy
during an awake state, the WTRU may perform one or more of the
following. The WTRU may trigger a timer based on the last received
transmission or based on the time the WTRU entered the awake state.
If the WTRU triggers a timer, the length of the timer may be
relatively long, for example to enable more occasions in which the
WTRU is reachable. For example, the timer may correspond to the
amount of time the WTRU remains in an active state. The WTRU may
change states and/or go to sleep when the timer expires. For
example, the timer may be longer than if the channel had been
unoccupied in order to allow for the network to acquire the channel
and/or let the WTRU know if it will be scheduled.
[0121] The WTRU may pause an ongoing timer until the WTRU
determines that the channel is not occupied (e.g., occupied by an
interfering node) or until the WTRU resets the timer due to one or
more of the scenarios described herein. The WTRU may add time to a
timer that may be already running. For example, if the WTRU enters
an awake state and observes little or no channel occupancy, the
WTRU may trigger a first timer, which may be shorter than a timer
that would be used had the channel been determined to have high
occupancy. If the WTRU senses an increase in channel interference
(e.g., indicating that the channel occupancy is high), the WTRU may
extend the timer such that a longer overall timer value may be
used. The WTRU may reset a timer. For example, the WTRU may reset
the timer based on a determination that channel occupancy is
high.
[0122] A WTRU may receive an indication to toggle to a sleep state.
For example, the indication may be an explicit indication or an
implicit indication to toggle to a sleep state.
[0123] A WTRU may receive a transmission(s) during an awake time
period. The WTRU may determine (e.g., determine to be aware) of the
time remaining for channel occupancy. For example, the WTRU may
determine to be aware of the time remaining for channel occupancy
based on the maximum channel occupancy time (MOOT). The WTRU may
receive an indication (e.g., an explicit or an implicit
indication), within the COT, signaling whether or not the network
intends to reacquire the channel (e.g., reacquire the channel
immediately after the MOOT expires). If the WTRU receives an
indication that the network will not attempt to reacquire the
channel at the end of the MOOT, the WTRU may enter (e.g., may
immediately enter) a sleep state upon expiration of the MOOT. For
example, the timing of toggling to a sleep state may have
precedence over an active and non-expired awake timer. If the WTRU
receives an indication that the network will attempt to reacquire
the channel at the end of the MOOT, the WTRU may trigger an awake
timer. For example, a new awake timer may be a specific timer
duration based on the reception of such an indication. The value of
the timer may be indicated (e.g., explicitly or implicitly
indicated) by the network, or the value may be configured (e.g.,
fixed). In examples, the timer may be infinite, and the WTRU may
remain awake until the network reacquires the channel. If the timer
is infinite and the WTRU remains awake until the channel is
reacquired, a regular awake timer may be restarted when the WTRU
receives an indication that the channel has successfully been
reacquired. The WTRU may refrain from restarting the regular awake
time until the channel is acquired.
[0124] A WTRU may receive an indication with one or more BWPs of a
carrier where a channel may be reacquired. For example, the
indication may be provided to the WTRU in an indication (e.g., the
same indication) that the network intends to reacquire the channel
after the current MOOT expires. If the network indicates that the
channel may be acquired using a BWP from a set of BWPs, the WTRU
may monitor multiple BWPs (e.g., the set of BWPs) during the awake
time.
[0125] A WTRU may transmit data using an adaptive DRX cycle. For
example, an adaptive DRX cycle may be or may include determining
and/or varying sleep and/or awake timers based on a transmission
history of a WTRU. The timers used may change and/or the values of
DRX timers may change in an adaptive DRX cycle. For example, the
timers may be changed and/or the length of the timers may be
changed based on observed conditions, such as channel occupancy
and/or channel acquisition.
[0126] A WTRU may determine the duration of a timer for a first
state. For example, the WTRU may determine the duration of a timer
for a first state based on an event occurring in a second state.
The WTRU may monitor a channel (e.g., an unlicensed channel) for
signals during an awake state or a monitoring state. The signals
may be or may include a signal indicating that the channel has been
acquired (e.g., via a channel acquisition indication) and/or a
signal including a message about scheduling information for a
transmission to or from the WTRU on the channel. In examples, the
WTRU may determine a timer duration for a sleep state (e.g., the
timer triggered upon entering the sleep state). The WTRU may
determine a timer duration for a sleep state based on whether the
WTRU received a transmission during the awake state (e.g., a
monitoring state, such as a first monitoring state). For example,
if the WTRU did not receive a transmission (e.g., neither the
channel acquisition indication signal nor the scheduling
information signal) during the awake state (e.g., the monitoring
state), the WTRU may use a first timer (e.g., or timer duration)
for one or more subsequent sleep states. Such a first timer
duration may be a determined from a set of timer values (e.g., a
configurable set of timer values) and/or may be for a short
duration. The WTRU using the first timer duration with the short
duration may allow the WTRU to enter the subsequent awake
state/monitoring state (e.g., the second awake state/the second
monitoring state).
[0127] If the WTRU receives one or more scheduling information
(e.g., such as DCIs), the WTRU may use a second timer (e.g., or
timer duration). The second timer duration may be determined from
the set of timer values (e.g., the configurable set of timer
values) and may be for a longer duration (e.g., longer than the
first timer). The WTRU may send or receive the transmission based
on the one or more scheduling information and/or DCIs.
[0128] If the WTRU does not receive scheduling information (e.g.,
DCI), but receives an indication that the channel was acquired by a
network during the awake state (e.g., as discussed herein), the
WTRU may use a third timer (e.g., or timer duration). The third
timer may have similar (e.g., the same) time value as the second
timer. If the WTRU receives no transmission from the network during
the awake period, the WTRU may determine the timer duration based
on the channel occupancy techniques discussed herein.
[0129] A WTRU may receive an indication (e.g., an explicit
indication) from a network (e.g., a gNB) during an awake state,
indicating a timer duration to use for one or more subsequent sleep
periods. The indication may be used (e.g., may also be used) to
reconfigure timers and/or triggers for subsequent awake states.
[0130] A WTRU may determine a timer value as a function. For
example, the WTRU may determine a timer value as a function based
on receiving one or more transmissions during the awake time and a
previous value of the timer. For example, when the WTRU enters an
awake period, the WTRU may start a first timer. If the first timer
expires before the WTRU receives a transmission, the WTRU may start
a second timer and may enter and remain in a sleep state until the
expiration of the second timer. The WTRU may enter (e.g., reenter)
the awake period using the first timer. If the WTRU receives no
transmission and the first timer expires during the subsequent
awake time (e.g., the second awake time), the WTRU may start the
second timer and enter/remain in the sleep state (e.g., the second
sleep state). The duration of the second timer may be determined
based on the WTRU not receiving a transmission during the previous
awake state and/or a timer value used for a previous sleep state.
For example, if the WTRU does not receive a transmission during an
awake state (e.g., subsequent awake state, such as the second awake
state), the value of the second timer may decrease when compared to
the value of the second timer associated with the previous sleep
state (e.g., the first sleep state). For example, the value of the
second timer may decrease down to a configurable minimum value when
compared to the value of the second timer associated with the
previous sleep state (e.g., the first sleep state). If the WTRU
receives a transmission during the awake state (e.g., regardless of
whether the transmission is for the WTRU specifically or just to
indicate the channel has been acquired by the cell), the WTRU may
use a longer timer for a subsequent sleep period than the timer
used for a previous sleep period. For example, the longer timer may
be limited by a maximum value, which may be configured by the
network.
[0131] A value of an awake timer may be determined based on an
activity that occurred during a previous awake time and/or the
duration of a previous sleep timer. For example, if a WTRU does not
receive a transmission in one or more previous awake periods, the
WTRU may use a longer timer for a subsequent awake period. The WTRU
may use a longer time for a subsequent awake period given that the
channel may have high occupancy and the network may need more time
to acquire the channel. The subsequent awake period may have a
timer set to infinite to ensure the reception of one or more
transmissions.
[0132] FIG. 2 is an example of an adaptive DRX cycle. As shown in
FIG. 2, adaptive DRX configuration may be used to increase the
number of opportunities that a network (e.g., a gNB) may have of
acquiring a channel to reach a WTRU (e.g., in times of high channel
occupancy). The awake or sleep time may be based on the reception
of a signal (e.g., a channel acquisition signal and/or scheduling
information for a transmission to or from the WTRU on the channel)
in a previous and/or concurrent awake period. For example, as shown
in FIG. 2, during awake time 1 and awake time 2, a WTRU may monitor
a channel and may receive no transmission from a network (e.g., a
gNB). The subsequent sleep timers (e.g., sleep timer 2 and sleep
timer 3) may be shortened (e.g., shorten compare to sleep timer 1)
to provide more opportunities to the gNB to acquire the channel to
reach the WTRU. During an awake time 3, the WTRU may detect a
transmission. The transmission may not have assignment. For
example, the WTRU may receive a signal for channel acquisition, but
may not receive scheduling information for the transmission. The
WTRU may use shorter awake time (e.g., awake timer 2) and longer
subsequent sleep time (e.g., using adaptive DRX configuration, such
as sleep timer 1), for example based on receiving the signal during
awake time 3.
[0133] As shown in FIG. 2, the timers used for awake states and/or
the timers used for subsequent sleep states may be adapted based on
a reception of a transmission by a WTRU during the awake time. A
WTRU may determine to use (e.g., may be configured to use) a first
sleep timer. After the first sleep timer expires, the WTRU may
enter an awake state and monitor the PDCCH for transmissions. Upon
entering the first awake state, the WTRU may trigger a first timer
(e.g., long timer). Upon expiration of the first timer, the WTRU
may return to a sleep state and/or may reduce the sleep state timer
duration. When the WTRU receives a transmission from the network,
the first timer may be stopped, and a second timer (e.g., short
timer) may be triggered. The value of the short timer may be
determined. For example, the value of the short timer may be
determined as a function of a fixed or configurable value and the
time elapsed since the beginning of the awake time. Upon expiration
of the second timer, the WTRU may enter a sleep state having a
longer sleep state timer duration.
[0134] In examples, upon reception of a transmission from the
network, a WTRU may shorten the first timer (e.g., shorten by a
configurable amount of time). Upon expiration of the shortened
timer, the WTRU may enter a sleep state having a longer sleep state
timer duration. As illustrated in FIG. 2, during the first and
second awake times (e.g., awake time 1 and awake time 2), the WTRU
may not receive a transmission. As seen in FIG. 2, if the WTRU does
not receive a transmission within the first or the second awake
time, the WTRU may stay awake for the duration of the first awake
timer and subsequent sleep timers may be reduced. For example, as
shown in FIG. 2, sleep timer 2 may be shorter than sleep timer 1,
and sleep timer 3 may be shorter than sleep timer 2 and sleep timer
1. As seen in FIG. 2, the WTRU may receive a DL transmission (as
shown in FIG. 2, black square during Awake Timer 2) during a third
awake time (e.g., awake time 3). The transmission may be a DRS
transmission or an indication that the channel was acquired (e.g.,
a channel acquisition indication). If the WTRU receives a
transmission, validity criterion of the second awake timer (e.g.,
that the WTRU receives a transmission from the network) has been
achieved. The first timer may be stopped and the second timer may
be reset when the WTRU receives a PDCCH for a transmission other
than channel acquisition. If the WTRU receives a DL transmission
during an awake state, a subsequent sleep timer duration may be
increased. For example, the subsequent sleep timer duration may be
increased from a previous sleep timer duration up to a maximum
value. Table 1 illustrates an example MAC specification that may be
used to implement an example of adjustable timers (e.g., for the
awake state and/or the sleep state).
TABLE-US-00001 TABLE 1 1>If the MAC entity is in Active Time:
2>monitor the PDCCH 2>Start a first timer (e.g.,
drx-channel-occupation-unknown-timer) 2>If the PDCCH indicates a
channel occupied 3>Start a second timer (e.g.,
drx-channel-occupied-timer) 3>Stop the
drx-channel-occupation-unknown-timer if it is running 2>If the
PDCCH indicates a DL transmission or UL grant 3>Start or restart
a timer (e.g., drx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerUL or
drx-InactivityTimer) 3>Stop the drx-channel-occupied-timer if it
is running. 3>Stop the drx-channel-occupation-unknown-timer if
it is running 1>If the drx-channel-occupation-unknown-timer
expires 2>Enter sleep time 2>set drx-sleep-timer to a value
smaller than the previous drx-sleep-timer value to a minimum value)
2>start drx-sleep-timer 2>set
drx-channel-occupation-unknown-timer to a value larger than a
previous drx-channel- occupation-unknown-timer (up to a maximum
value).
[0135] An awake timer may be started at the beginning of an awake
period (e.g., at the beginning of an ON duration) or at the end of
a last scheduled DL transmission within the awake period. Upon
elapsing the awake timer, the WTRU may go to sleep state. The timer
(e.g., awake timer) may be considered elapsed if the full timer has
elapsed or if a WTRU has received a transmission (e.g., a
transmission indicating the WTRU go to sleep). An awake timer may
be cancelled based on one or more of the following. An awake timer
may be cancelled based on reception of a channel scheduling another
transmission. An awake timer may be cancelled based on reception of
a channel and/or a signal indicating a network (e.g., a gNB and/or
the like) has acquired the channel during the ON duration. An awake
timer may be cancelled based on reception of a signal indicating
the WTRU to monitor the PDCCH (e.g., wake-up signal).
[0136] Upon cancelling a first awake timer, the WTRU may start a
second awake timer. The second awake timer may be cancelled upon
reception of a DCI for that WTRU (e.g., WTRU with the second awake
timer). The WTRU may be configured to continue to use the second
awake timer until the DCI is received.
[0137] For example, a WTRU may be scheduled with a first awake
timer of duration n symbols and a second awake timer of duration m
symbols. Upon starting the ON duration, the WTRU may start the
first timer. In examples, if the WTRU receives no transmission
(e.g., from its serving cell) during the n symbols, the WTRU may go
back to sleep state. In examples, if the WTRU receives a signal
indicating that the channel has been acquired by a network (e.g., a
gNB and/or the like), the WTRU may cancel the first awake timer and
may start a second awake timer. If the WTRU receives no DCI during
the subsequent m symbols, the WTRU may return to sleep state. The
value of m for the second awake timer may depend on how much time
has elapsed since the first awake timer was started. For example,
the value of m may be defined as m=k-j, where k may be fixed, and j
may be the time between the start of the awake period (e.g., or ON
duration) and the time that the second timer was started.
[0138] A WTRU may monitor a channel for the presence of a wake-up
signal (WUS). The signal (e.g., WUS) may include, but not limited
to a reference or synchronization signal scrambled with a specific
sequence, a PDCCH transmission with cyclic redundancy check (CRC)
scrambled with a specific RNTI, and/or the like.
[0139] In examples, upon reception of a WUS, a WTRU may update an
ongoing awake timer. For example, the WTRU may cancel a first awake
timer and may trigger a second awake timer.
[0140] In examples, a WTRU may monitor for a WUS during a sleep
state. Reception, or lack thereof, of an awake signal during a
sleep state may be used to determine the awake timer (e.g., or
duration thereof) of a subsequent awake state. For example, if a
WTRU receives a WUS during a sleep state, the WTRU may use a first
awake timer in a subsequent awake state. If the WTRU does not
receive a WUS signal during a sleep state, the WTRU may use a
second awake timer in a subsequent awake state. For example, the
second awake timer may have a timer of duration 0, such that the
WTRU restarts (e.g., immediately restarts) a DRX cycle.
[0141] A network may attempt to transmit the WUS multiple times or
in multiple time/frequency resources for a WTRU (e.g., for
robustness). The WTRU may monitor the multiple resources, at least
until successful reception of a WUS in a period (e.g., in a sleep
state or in an ON duration).
[0142] A WTRU may receive and/or detect a WUS from a network. If a
WTRU receives or detects a WUS from a network, the WTRU may expect
a transmission (e.g., another transmission) during an ongoing or
subsequent ON duration. For example, the WTRU may detect a WUS in a
sleep state and may expect to receive a scheduling DCI in
subsequent ON duration (e.g., from a network). The WTRU may fail to
receive or detect a WUS in a sleep state, and the network may
indicate to the WTRU that the WTRU should not expect a transmission
(e.g., another transmission) in an ongoing or subsequent ON
duration. The information about whether or not to expect a
transmission may be used by the WTRU to determine the timer value
of a future sleep state (e.g., subsequent sleep state).
[0143] For example, during a first sleep period using a first sleep
timer, the WTRU may not detect one or more WUSs in a set of
resources. The set of resources may be used to provide the cell
multiple chances to transmit the WUS. Upon entering an awake state,
the WTRU may use a first awake timer. Upon re-entering the sleep
state (e.g., entering a second sleep state) at the end of the awake
period (e.g., if the WTRU has not been scheduled), the WTRU may
reuse the first sleep timer.
[0144] A WTRU may detect a WUS in one or more the configured WUS
resources. For example, a WTRU may detect a WUS in one or more the
configured WUS resources during the first sleep period. If the WTRU
detects a WUS in one or more the configured WUS resources during
the first sleep period, the WTRU may use a second awake timer upon
entering the awake state. If the WTRU receives a transmission
during the awake period, upon returning to the sleep state, the
WTRU may reuse the first sleep timer. The transmission that the
WTRU receives during the awake period may include one or more of a
scheduling DCI, a data transmission, a signal indicating the
channel has been acquired by a cell, and/or the like. If the WTRU
does not receive a transmission during the awake period following
the sleep period where the WTRU detected a WUS, the WTRU may use a
second sleep timer (e.g., shorter than the first sleep timer) upon
returning to the sleep state.
[0145] FIG. 3 illustrates an example for DRX timer determination
based on wake-up signal detection. For example, FIG. 3 may use WUS
detection during a sleep state. In examples, if the WTRU detects
one or more WUSs during a sleep state, WTRU may use a first timer
(e.g., awake timer 1) in a subsequent awake state (e.g., ON
duration). If the WTRU receives one or more transmissions during
the ON duration (e.g., subsequent ON duration/subsequent awake
state), the WTRU may return to the sleep state and may use a sleep
timer 1 (e.g., upon expiration of the awake timer 1). If the WTRU
receives no transmission during the ON duration, the WTRU may
return to the sleep state and may use a sleep timer 2 (e.g., upon
expiration of the awake timer 1). The sleep timer 2 may have less
duration than the duration of the sleep timer 1. The transmission
expected during an awake period following a sleep period, where a
WUS was received, may include one or more of a scheduling DCI, a
signal indicating the channel is acquired by a cell, a data
transmission, an RS transmission, and/or the like. If during the
sleep state, the WTRU did not detect a WUS, the WTRU may enter the
awake state and may use an awake timer 2 (e.g., upon expiration of
the sleep timer). The awake timer 2 may have less duration than the
duration of the awake timer 1. The WTRU may not expect a
transmission during the awake state. The WTRU may not expect a
transmission during the awake state. For example, the WTRU may not
expect a transmission during the awake state due to a lack of a
preceding WUS. If the WTRU does not expect a transmission during
the awake state, the WTRU may use a sleep timer (e.g., a fixed
sleep timer) for a subsequent sleep state (e.g., regardless of
whether the WTRU receives a transmission during the awake
period).
[0146] In examples, a WTRU may be configured with two or more DRX
configurations and may apply the appropriate configuration based on
a set of conditions. In examples, the WTRU may use a DRX cycle
(e.g., a short DRX cycle or a long DRX cycle) based on such
conditions. The set of conditions may provide a DRX configuration
allowing for more scheduling opportunities (e.g., shorter DRX
cycle) is applied when the WTRU determines that the network may not
have successfully acquired the channel.
[0147] For example, two or more (e.g., two) DRX configurations may
be configured. The WTRU may apply a first DRX configuration (e.g.,
or a short DRX cycle) under one of more of the following
conditions. The WTRU may apply a first DRX configuration (e.g., or
a short DRX cycle) if a drx-onDuration timer has expired. The WTRU
may apply a first DRX configuration (e.g., or a short DRX cycle) if
PDCCH was not received while the drx-onDuration timer was running
(e.g., on or more of an inactivity timer, DL or UL retransmission
timer, and/or DL or UL HARQ RTT timer is not running). The WTRU may
apply a first DRX configuration (e.g., or a short DRX cycle) if a
wake-up signal was received before a drx-onDuration was last
started. The WTRU may apply a first DRX configuration (e.g., or a
short DRX cycle) if a wake-up timer is running, where a wake-up
timer may be started upon reception of a wake-up signal and may be
stopped upon reception of a PDCCH.
[0148] In examples, a wake-up timer may be restarted upon reception
of another wake-up signal. For example, a wake-up timer may be
restarted upon reception of another wake-up signal prior to the
wake-up timer being stopped or expiring.
[0149] The WTRU may apply a second DRX configuration (e.g., or a
long DRX cycle) under one or more of the following conditions. The
WTRU may apply a second DRX configuration (e.g., or a long DRX
cycle) if a PDCCH was received. The WTRU may apply a second DRX
configuration (e.g., or a long DRX cycle) if a wake-up timer
expires.
[0150] A WTRU may enter an IDLE mode when operating in an adaptive
DRX cycle. In IDLE mode, awake states or periods of a WTRU may be
configured such that they match paging occasions and/or system
information (SI) transmission occasions. The timing of a toggle
(e.g., from a low activity or sleep state to a higher activity or
awake state) may be fixed (e.g., fixed independently) of the time
when the WTRU enters a sleep state.
[0151] When a WTRU is in an IDLE mode awake state, one or more of
the following may occur. For example, when a WTRU is in an IDLE
mode awake state, the WTRU may receive DCI indicating paging
information for the WTRU. When a WTRU is in an IDLE mode awake
state, the WTRU may receive DCI scheduling SI. When a WTRU is in an
IDLE mode awake state, the WTRU may receive a signal indicating a
channel has been acquired (e.g., by the network). If the WTRU
receives a signal indicating that a channel has been acquired, the
WTRU may assume that the WTRU not receiving DCI for paging or SI
transmission is not caused by the network being unable to acquire
the channel.
[0152] When a WTRU receives DCI indicating paging or SI
transmission, the WTRU may proceed with the appropriate processes
to receive such transmissions. When a WTRU receives a signal
indicating that a channel has been acquired (e.g., and no other
DCI), the WTRU may return to a sleep state (e.g., until a later
planned paging or SI occasions).
[0153] If a WTRU does not receive a transmission during IDLE mode
active period (e.g., paging occasion (PO) or paging frame (PF)) or
does not receive a signal indicating channel acquisition during an
awake state, the WTRU may be unsure of whether the network acquired
the channel during the awake period. The WTRU may remain in the
awake state longer based on not receiving a signal (e.g., any
signals) from the network. For example, the WTRU may trigger a
timer at the beginning of an awake state. The timer may be
cancelled upon reception of one of the above signals or may expire
naturally. Upon expiration of the timer, the WTRU may return to
sleep state.
[0154] A WTRU may determine a timer value for a subsequent awake
period.
[0155] The timing of a subsequent paging or SI transmission
occasion may be determined based on the reasoning or cause for
entering sleep state. For example, if during an awake time (e.g.,
or PO and/or PF) and if the WTRU receives a DCI for paging or for
SI transmission, the WTRU may determine a future paging or SI
transmission occasion based on a first function (e.g., or a
function using a first set of inputs, such as type of received
transmission or DRX cycle duration). If during an awake time, the
WTRU receives a signal indicating that a channel has been acquired
(e.g., and does not receive anything else from the network), the
WTRU may determine a future paging or SI transmission occasion
based on a second function (e.g., or a function using a second set
of inputs, such as DRX cycle duration). If during an awake time,
the WTRU does not receive a transmission, the WTRU may determine a
future paging or SI transmission occasion from a third function
(e.g., or a function using a third set of inputs, such as number of
consecutive POs and/or PFs without receiving a transmission, or DRX
cycle duration).
[0156] For example, the system frame number (SFN) of a PF for a
WTRU may be determined based on by the following equation (1):
(SFN+PF_offset-LBT_offset)mod T=(T div N)*(WTRU_ID mod N),
LBT_offset=LBT_Counter*LBT_SFN_Delta (1)
[0157] Parameter T may be a DRX cycle. Parameter N may be
N=min(T,nB). Parameter nB may be the number of total paging
occasions in T. Parameter PF_offset may be an offset used for PF
determination. Parameter WTRU_ID may be WTRU_ID=IMSI mod 1024.
Parameter LBT_SFN_Delta may be an offset used if the WTRU does not
determine the presence of any transmission from the gNB during a
given PF. Parameter LBT_Counter may count the number of consecutive
PFs where the WTRU does not receive any transmission from the gNB.
LBT_Counter may reset to zero when a WTRU receives a transmission
from the gNB in a PF.
[0158] In examples, a signal transmitted during an awake state may
indicate (e.g., explicitly indicate) the timing (e.g., or the
inputs to a function to determine the timing) of a future paging or
SI transmission occasions to the WTRU. If the WTRU receives a
transmission during an awake state, the WTRU may enter a sleep
state for a longer duration. If the WTRU does not receive a
transmission during an awake state, the WTRU may enter the sleep
state for a shorter duration.
[0159] In examples, a WTRU may receive an indication of the timing
for one or more subsequent paging or SI transmission occasions
during a transmission in an awake state. For example, the network
may acquire the channel during an awake state of a WTRU but may not
be able to schedule that WTRU during an ongoing channel occupancy
time. For example, this may be due to possibly higher priority
traffic for other WTRUs. In such a case, the WTRU may receive an
indication to defer its awake period and/or to wake up in an
aperiodic manner at an indicated or configurable future time. At
the future wake up time, the WTRU may expect the transmission of
one or more signals intended for the WTRU. The awake time may be
exited after the WTRU receives one or more signals (e.g., and
possibly another deferral to another wake up time). The WTRU may be
configured to remain in the awake time until the WTRU receives the
expected signals.
[0160] For example, a WTRU may receive a transmission during an
awake state (e.g., during a PF) indicating that the WTRU may behave
as though the WTRU did not receive any transmission during the PF.
For example, in a high paging load scenario, the network may not
have the resources to page the WTRU at that present time and/or may
wish to indicate to the WTRU to use a modified PF function to
reduce the paging latency. As such, the WTRU may use the modified
PF function described herein to determine a future PF as if the
WTRU had not received any transmissions during the PF. One or more
different WTRUs may have different LBT_SFN_Delta, and the load of
WTRUs that may need to be paged but could not be paged during a
channel occupancy time, may be spread. For example, LBT_SFN_Delta
may be determined as a function of WTRU ID.
[0161] Upon reception of a paging message, a WTRU may be indicated
and/or configured to use a backoff value before beginning random
access. The backoff value may be random. If a backoff time is not
used, a gNB may end up having clusters of paging message
transmissions (e.g., due to high channel load). If a gNB ends up
having clusters of paging message transmission due to high channel
load, one or more (e.g., multiple) WTRUs may respond (e.g., respond
simultaneously) to pages and may reduce the random access (RA)
capacity, or may prohibitively increase the channel load. A WTRU
may use a backoff value (e.g., random backoff value) to determine a
random time offset between reception of a paging message and the
beginning of a RA procedure.
[0162] In examples, a WTRU may receive an indication during a PF
that WTRU may reselect to a different cell (e.g., and/or sub-band
and/or beam). Upon reselecting to the different cell/sub-band/beam,
the WTRU may begin (e.g., immediately begin) monitoring for the
reception of a paging message.
[0163] Paging occasion(s) and/or paging frame(s) (e.g., conditional
paging occasion(s) and/or paging frame(s)) may be triggered. For
example, a WTRU may activate, deactivate, etc., paging occasion(s)
and/or paging frame(s) based on one or more conditions.
[0164] A WTRU may be configured with one or more of the following.
The WTRU may be configured with one or more (e.g., multiple) paging
occasions in a paging frame. The WTRU may be configured with one or
more (e.g., multiple) paging occasions (POs) outside a paging
frame. The WTRU may be configured with one or more (e.g., multiple)
paging frames per DRX cycle. For paging occasion(s) outside a
paging frame, such POs may occur outside of a PF and may be
associated to that PF. For example, the WTRU may determine the
timing of the POs based on the timing of an associated PF. For
paging frame(s) per DRX cycle, a WTRU may be configured with one or
more (e.g., multiple) PFs per DRX cycle. For example, a (e.g.,
each) PF may have its own set of POs.
[0165] When configured with one or more (e.g., multiple) POs and/or
PFs (e.g., per DRX cycle), a WTRU may be configured with a PO
type(s) and/or PF type(s) for a (e.g., each) PO and/or PF. In
examples, a PO and/or a PF (e.g., a first type of PO and/or a first
type of PF) may be considered active (e.g., always active). A WTRU
may monitor the appropriate PDCCH in active POs and/or PFs. A PO
and/or PF (e.g., a second type of PO and/or a second type of PF)
may be considered conditional. A conditional PO and/or a
conditional PF may be activated or deactivated. For example, a
conditional PO and/or PF may be activated based on a pre-determined
or a configurable rule. For example, a conditional PO and/or a
conditional PF may be activated and may be used by a WTRU to
monitor for a transmission, such as a paging message, SI, and/or
the like. For example, a conditional PO and/or a conditional PF may
be deactivated and may not be used by a WTRU to monitor for a
transmission.
[0166] The activation or deactivation of a conditional PO and/or a
conditional PF may be based on one or more of the following. The
activation or deactivation of a conditional PO and/or a conditional
PF may be based on reception of a signal or lack of reception a
signal in a PO and/or PF (e.g., previous and/or associated PO
and/or PF). The activation or deactivation of a conditional PO
and/or a conditional PF may be based on reception of a signal prior
to the conditional PO and/or PF. The activation or deactivation of
a conditional PO and/or a conditional PF may be based on one or
more measurements. The activation or deactivation of a conditional
PO and/or a conditional PF may be based on one or more network
indications. The activation or deactivation of a conditional PO
and/or a conditional PF may be based on a time. The activation or
deactivation of a conditional PO and/or a conditional PF may be
based on a WTRU state.
[0167] The activation or deactivation of a conditional PO and/or PF
may be based on reception of a signal or lack of reception of a
signal in a PO and/or PF (e.g., previous and/or associated PO
and/or PF). In examples, if a WTRU does not receive a transmission
in a PO (e.g., a first PO), the WTRU may activate one or more
conditional POs. The WTRU may be configured with a set of
associated POs, for example where one or more members of the set
may be active (e.g., always active), and the rest may be
conditional. The activation of PO may be based on the presence or
lack of a signal, for example the presence or lack of a signal in a
set of dependent POs. For example, a first conditional PO may be
based on signals present or not in the always active PO. A second
conditional PO may be based on signals present in either the always
active PO or the first conditional PO, and so on. In examples, a
conditional PO may be assumed activated and may be deactivated upon
reception of a transmission in a previous PO.
[0168] The activation or deactivation of a conditional PO and/or PF
may be based on reception of a signal prior to the conditional PO
and/or PF. For example, a WTRU may expect an energy signal (e.g., a
low energy signal such as a wake-up signal) prior to a PO and/or a
PF and prior to activating the PO and/or PF.
[0169] The activation or deactivation of a conditional PO and/or PF
may be based on one or more measurements. For example, a WTRU may
perform a measurement prior to a PO and/or PF possibly in a
previous and/or associated PO and/or PF. Such a measurement may
determine whether the channel was acquired by a serving cell. For
example, the measurement may indicate whether the channel was
acquired during the previous PO and/or PF. Upon determination that
the serving cell was not able to transmit during the previous PO
and/or PF, the WTRU may activate a conditional PO and/or PF.
[0170] The activation or deactivation of a conditional PO and/or PF
may be based one or more of network indications (e.g., gNB
indications). The network indication(s) (e.g., gNB indication(s))
may be or may include an information element in a DCI (e.g., a bit
toggled on). A WTRU may be triggered by a network transmission
(e.g., gNB transmission) to activate or deactivate a conditional PO
and/or PF. The network transmission (e.g., gNB transmission) may be
an implicit indication. For example, the presence of a signal
(e.g., an RS) may activate or deactivate a PO and/or PF.
[0171] The activation or deactivation of a conditional PO and/or PF
may be based on time (e.g., time since last activated PO and/or
PF). For example, a WTRU may activate a PO and/or PF if a time
(e.g., certain amount of time) has elapsed since the last time that
(e.g., or another) PO and/or PF was deemed activated.
[0172] The activation or deactivation of a conditional PO and/or PF
may be based on a WTRU state. A WTRU may be configured with a PO
and/or a PF monitoring state. Depending on the state, the WTRU may
monitor one or more different sets of POs and/or PFs. For example,
in a first state, the WTRU may activate one or more (e.g., all) POs
in one or more (e.g., all) PFs. In a second state, a WTRU may
activate a (e.g., single) PO in one or more (e.g., all) PFs. In a
third state, the WTRU may activate a PO (e.g., single PO) in a
subset of states. Such states may be semi-statically configured.
The configuration (e.g., semi-static configuration) may include the
set of POs and/or PFs to monitor for a (e.g., each) state. A
dynamic activation of conditional POs and/or PFs may be occur and
the set of conditional POs and/or PFs may be based on the state of
a WTRU as described herein.
[0173] Upon activating a PF, a WTRU may activate one or more (e.g.,
all) associated POs.
[0174] A WTRU may have a PF (e.g., a single PF) per DRX cycle. The
WTRU may be configured with a PO (e.g., a first PO). The first PO
may be associated with the PF that is considered active (e.g.,
always active). The WTRU may be configured with N other POs that
may be considered conditional. If the WTRU does not receive a
transmission within a first PO, the WTRU may activate one or more
conditional POs in the PF and may monitor PDCCH in the conditional
PO(s).
[0175] A WTRU may have one or more POs tied to a PF. The PF (e.g.,
and one or more associated POs) may be conditional. Upon reception
of a trigger signal (e.g., a wake-up signal prior to the PF), the
WTRU may activate one or more of the POs associated to the PF.
[0176] When a conditional PO and/or PF is activated, a WTRU may
remain active for a set period of time (e.g., or instances) or
until being deactivated. For example, if a WTRU is configured to
remain active for a set period of time (e.g., or instances), an
activated PO and/or PF may be activated for an instance and the
WTRU may need activation or triggering for a (e.g., each) possible
instance (e.g., subsequent instance(s)).
[0177] An awake period may terminate upon reception of a
transmission by the WTRU.
[0178] In examples, a WTRU may enter and remain in an awake state
until the WTRU receives one or more channels or signals intended
for the WTRU. For example, the WTRU may remain in the awake state
until the WTRU receives one or more DCIs for paging or SI, and/or
until the WTRU receives an indication of a channel being
successfully acquired. The WTRU may determine a future paging or SI
transmission occasion based on the timing of a successful
reception. In examples, the WTRU may determine a future paging or
SI transmission occasion based on the timing of a last reception
during an awake period.
[0179] A WTRU may perform a resynchronization of an awake
period.
[0180] A WTRU may miss the transmission of a signal and/or a
channel during its awake time. For example, a lack of
synchronization between the WTRU and the gNB about the timing of a
future paging or SI transmission occasion may cause the WTRU to
miss the transmission. A WTRU may have a set of fixed occasions
when the WTRU must wake up, regardless of the activity of the WTRU
during a previous awake state which may dynamically adjust timer
values as described herein. The mandatory wake up occasions may be
configurable and/or may be determined by a function using
parameters obtained in a master information block (MIB) or system
information block (SIB).
[0181] In examples, the WTRU may determine the timing of a future
paging or SI transmission occasion based on the beginning of a
previous awake state. The determined timing may be variable and/or
may be based on activity during an awake state. The configuration
of possible sleep durations may overlap (e.g., may be made to
ensure to overlap) with one another. The longer duration may be an
integer multiple of a shorter duration.
[0182] In examples, upon an unsuccessful reception of a
transmission during one or more awake periods, a WTRU may expect a
modification of its paging or SI transmission occasion periodicity.
After a set of awake periods (e.g., possibly consecutive awake
periods) where a WTRU does not receive a transmission, the WTRU may
remain awake (e.g., in a next awake period) until the WTRU receives
one or more transmissions. For example, the WTRU may remain awake
until the WTRU receives an SI transmission to ensure the paging
occasions are synchronized.
[0183] A WTRU may monitor one or more paging messages on one or
more (e.g., multiple) unlicensed channels.
[0184] A WTRU may be configured to monitor one or more (e.g.,
multiple) unlicensed channels for paging messages. For example, an
unlicensed channel may refer to a combination of a cell, a
sub-band, and/or a beam. In examples, a WTRU may be configured with
different PF for each unlicensed channel. In examples, the WTRU may
have a PF (e.g., a single PF) that the WTRU may monitor one or more
(e.g., all) configured unlicensed channels.
[0185] In examples, a WTRU may have an unlicensed channel (e.g., a
primary unlicensed channel) that the WTRU may monitor for paging
messages in a PF. If the WTRU does not receive a transmission from
a serving cell during a PF, the WTRU may begin monitoring one or
more secondary unlicensed channels. For example, if the WTRU does
not receive a transmission from a serving cell during a PF, the
WTRU may begin monitoring one or more secondary unlicensed channels
a new set of PFs. The WTRU may cycle through one or more different
unlicensed channels. For example, the WTRU may cycle through one or
more different unlicensed channels until reception of one or more
transmissions from a serving cell (e.g., cycling within a PF or
cycling among PFs). Upon reception of a transmission on an
unlicensed channel, the WTRU may return to monitoring for paging
messages in PFs on the primary channel, or the WTRU may make the
unlicensed channel that received the transmission the new primary
unlicensed channel (e.g., and/or may continue monitoring that
channel in configured PFs).
[0186] A WTRU may monitor paging messages in PFs from a set of
cells. The set may include the currently selected cell along with
up to n previously selected cells. In examples, the set of cells
may include one or more (e.g., all) cells with reference signal
receive power (RSRP) (e.g., or reference signal receive quality
(RSRQ)) above a threshold, or within an RSRP threshold of the
selected cell. In examples, the set of cells may include one or
more (e.g., all) cells with channel occupancy below a threshold
value.
[0187] A WTRU may monitor a channel (e.g., an unlicensed channel)
for a signal(s) associated with a transmission during a monitoring
period (e.g., a first monitoring period). Based on the signal(s)
received during the monitoring period (e.g., the first monitoring
period), the WTRU may determine a time (e.g., a start time) of a
subsequent monitoring period (e.g., a second monitoring period).
For example, the WTRU may monitor for a signal(s) during the
monitoring period for a signal for an indication that the channel
has been acquired (e.g., channel acquisition) and/or a signal for a
message that includes scheduling information for a transmission to
and/or from the WTRU on the channel. A RS may be an example signal
for the indication that the channel has been acquired. Downlink
control information may be an example signal for the indication
that the channel has been acquired.
[0188] The WTRU may determine a subsequent monitoring period (e.g.,
a second monitoring period) based on the signals received during
the previous monitoring period (e.g., the first monitoring period).
The WTRU may determine that the subsequent monitoring period (e.g.,
the second monitoring period) may occur at a first time based on
receiving the signal that indicates the channel has been acquired
during the first monitoring period. The WTRU may determine that the
subsequent monitoring period (e.g., the second monitoring period)
may occur at a second time based on not receiving the signal that
indicates the channel acquisition during the first monitoring
period. The WTRU may send or receive a transmission on the channel
based on receiving the signal for the channel acquisition and the
message that includes scheduling information.
[0189] The WTRU may determine a subsequent monitoring period (e.g.,
a second monitoring period) based on the signals received during
the previous monitoring period (e.g., the first monitoring period).
For example, the WTRU determine that the subsequent monitoring
period (e.g., the second monitoring period) may occur at a first
time based on receiving the signal that indicates the channel has
been acquired, but not the signal associated with the scheduling
information for the transmission during the first monitoring
period. The WTRU may determine that the subsequent monitoring
period (e.g., the second monitoring period) may occur at a second
time based on not receiving neither the signal that indicates the
channel acquisition nor the signal associated with the scheduling
information for the transmission during the first monitoring
period.
[0190] The WTRU may determine a duration (e.g., a minimum duration)
of the second monitoring period to a first duration based on
receiving the signal for channel acquisition but not receiving the
signal for the message including scheduling information for the
transmission to and/or from the WTRU on the channel during the
first monitoring period. The WTRU may determine the duration (e.g.,
the minimum duration) of the second monitoring period to the second
duration based on not receiving the signal for channel acquisition
and not receiving the signal for the message including scheduling
information for the transmission to and/or from the WTRU on the
channel during the first monitoring period. The first duration may
be longer than the second duration.
[0191] In examples, the first and the second monitoring periods
described herein may correspond to active periods of DRX cycles.
For example, the first and the second monitoring periods described
herein may correspond to on durations of a DRX cycle. A time
between an end of the first monitoring period and a start of the
second monitoring period may correspond to a sleep period of the
DRX cycles. The WTRU may determine the first time (e.g., the WTRU
receiving the channel acquisition signal during the first
monitoring period) based on a long DRX cycle configuration. The
WTRU may determine the second time (e.g., the WTRU not receiving
the channel acquisition signal during the first monitoring period)
based on a short DRX cycle configuration.
[0192] In examples, the first and the second monitoring periods
described herein may correspond to a first paging occasion and/or
paging frame and a second paging occasion and/or paging frame,
respectively.
[0193] The WTRU may consider an indication (e.g., in the channel
acquisition signal) that the WTRU may go to sleep until a start of
the second monitoring period based on the WTRU receiving the
channel acquisition signal (e.g., but not receiving the signal for
the message for scheduling information for the transmission) during
the first monitoring period.
[0194] A WTRU may determine one or more parameters of a current
and/or upcoming DRX cycle based on the presence and/or absence of a
signal during a current awake period. Based on the determination,
the WTRU may provide more opportunities to a network to acquire a
channel to reach the WTRU.
[0195] For example, one or more of the following may be performed.
The WTRU may be configured with multiple DRX durations. The WTRU
may wake up from a DRX cycle at expiration of a first timer. The
WTRU may monitor a presence of a signal. For example, the WTRU may
monitor whether scheduling information (e.g., a PDCCH) for a
transmission to assign resources or page a WTRU and/or a
transmission indicating a cell acquired the channel (e.g.,
unlicensed channel). If the WTRU receives a signal indicating that
a channel has been acquired and no other transmission, the WTRU may
return to DRX using a first DRX duration. If the WTRU does not
receive a (e.g., any) transmission from the cell (e.g., neither the
channel acquisition signal nor the scheduling information signal),
the WTRU may return to DRX using a second DRX duration. The second
DRX duration may have short duration (e.g., shorter duration than
the first DRX duration).
[0196] A WTRU may determine one or more parameters of a current
and/or upcoming DRX cycle based on the reception, or lack thereof,
of a signal in a previous or current awake period.
[0197] A WTRU may receive an indication to enter (e.g., immediately
enter) DRX state (e.g., at conclusion of COT).
[0198] A WTRU may determine the timing of an aperiodic PO and/or PF
based on the reception, or lack thereof, of a signal during a
previous PO and/or PF.
[0199] A WTRU may receive an indication in a PO and/or PF of the
timing of an upcoming aperiodic PO and/or PF.
[0200] Although features and elements are described above in
particular combinations, one of ordinary skill in the art will
appreciate that each feature or element can be used alone or in any
combination with the other features and elements. In addition, the
methods described herein may be implemented in a computer program,
software, or firmware incorporated in a computer-readable medium
for execution by a computer or processor. Examples of
computer-readable media include electronic signals (transmitted
over wired or wireless connections) and computer-readable storage
media. Examples of computer-readable storage media include, but are
not limited to, a read-only memory (ROM), a random access memory
(RAM), a register, cache memory, semiconductor memory devices,
magnetic media such as internal hard disks and removable disks,
magneto-optical media, and optical media such as CD-ROM disks, and
digital versatile disks (DVDs). A processor in association with
software may be used to implement a radio frequency transceiver for
use in a WTRU, UE, terminal, base station, RNC, or any host
computer.
* * * * *