U.S. patent application number 16/324481 was filed with the patent office on 2019-06-13 for connectivity supervision and recovery.
The applicant listed for this patent is IDAC Holdings, Inc.. Invention is credited to Yugeswar Deenoo, Ghyslain Pelletier, Ping Hsuan Tan.
Application Number | 20190182884 16/324481 |
Document ID | / |
Family ID | 59700201 |
Filed Date | 2019-06-13 |
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United States Patent
Application |
20190182884 |
Kind Code |
A1 |
Deenoo; Yugeswar ; et
al. |
June 13, 2019 |
CONNECTIVITY SUPERVISION AND RECOVERY
Abstract
Systems, methods, and instrumentalities are disclosed for
connectivity supervision and recovery. A WTRU may supervise its
capability to transmit and receive data, including in the absence
of a control channel (e.g. grant-less transmission). A supervision
framework may permit a WTRU to supervise, for example, quality of a
feedback channel, quality of reciprocal resources and/or
transmission attempts. A supervision process may be a function of a
control channel structure or WTRU state. A supervision process may
be associated with a quality of service. A supervision process may
be based on WTRU transmission for energy/resource efficient
operation. Multiple Recovery procedures may be defined. A recovery
procedure may be a function of a supervision process. A recovery
procedure may be optimized for low latency services. Recovery
procedures may involve dedicated resources for recovery, transition
to light connection, grant-less resource, etc. User plane recovery
may include reuse of layer2 context, data replication to companion
MAC instances, etc. Control plane recovery may use RAN paging, WTRU
triggered multi-connectivity, etc. A recovery procedure for a
supervision process associated with a beam process may include WTRU
triggering beam training/beam refinement, etc.
Inventors: |
Deenoo; Yugeswar; (Chalfont,
PA) ; Tan; Ping Hsuan; (Montreal, CA) ;
Pelletier; Ghyslain; (Montreal, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDAC Holdings, Inc. |
Wilmington |
DE |
US |
|
|
Family ID: |
59700201 |
Appl. No.: |
16/324481 |
Filed: |
August 10, 2017 |
PCT Filed: |
August 10, 2017 |
PCT NO: |
PCT/US2017/046335 |
371 Date: |
February 8, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62373071 |
Aug 10, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02D 70/24 20180101;
Y02D 70/1246 20180101; Y02D 70/1262 20180101; H04L 1/0061 20130101;
H04W 76/19 20180201; H04W 24/08 20130101; Y02D 70/00 20180101; H04W
16/28 20130101; H04W 76/15 20180201; Y02D 70/1242 20180101; Y02D
30/70 20200801; Y02D 70/21 20180101; Y02D 70/1244 20180101; Y02D
70/142 20180101; Y02D 70/1264 20180101; Y02D 70/144 20180101; H04W
68/005 20130101; H04W 80/02 20130101; Y02D 70/26 20180101; H04W
76/18 20180201; H04W 72/046 20130101; Y02D 70/1226 20180101; Y02D
70/146 20180101; Y02D 70/164 20180101; Y02D 70/23 20180101; Y02D
70/25 20180101 |
International
Class: |
H04W 76/18 20060101
H04W076/18; H04W 76/19 20060101 H04W076/19; H04W 16/28 20060101
H04W016/28; H04W 72/04 20060101 H04W072/04; H04L 1/00 20060101
H04L001/00; H04W 80/02 20060101 H04W080/02; H04W 24/08 20060101
H04W024/08; H04W 68/00 20060101 H04W068/00 |
Claims
1. A wireless transmit/receive unit (WTRU), comprising: a processor
configured to: establish at least a first supervision process and a
second supervision process, each associated with one or more radio
link failure (RLF) criteria and a type of transmission or
communication link between a node and the WTRU, wherein each of the
established supervision process is further associated with at least
one of: a bandwidth part (BWP), a beam process, a control channel,
and a quality of service (QoS); determine that a first RLF
criterion associated with a first supervision process of the
established supervision processes has been met; and perform a
recovery action associated with the first supervision process, in
response to a determination that the first RLF criterion has been
met, based on an identity of the first supervision process and a
status of at least the second supervision process.
2. The WTRU of claim 1, wherein each of the established supervision
processes comprises monitoring a predefined reference signal.
3. The WTRU of claim 1, wherein the type of transmission or
communication link is associated with a control channel or a
grant-less resource.
4. The WTRU of claim 1, wherein each of the established supervisory
processes comprises monitoring at least one signal characteristic
of the type of transmission or communication link or at least one
beam characteristic.
5. (canceled)
6. The WTRU of claim 4, wherein the at least one signal
characteristic comprises at least one of: an average packet delay,
signal quality, an average number of transmission attempts, one or
more cycle redundancy check (CRC) failures, an average data rate,
and a link quality considering interference.
7. The WTRU of claim 4, wherein the at least one beam
characteristic comprises at least one of: a quality metric, an
interference metric, a beam status, a transmission activity
associated with a beam, and a reception activity associated with a
beam.
8. The WTRU of claim 1, wherein the recovery action comprises at
least one of: triggering beam training, triggering a different
transmission type, triggering a different transmission time
interval, and changing the transmission time interval.
9. The WTRU of claim 1, wherein each of the established supervisory
processes comprises adiustinq a monitoring periodicity of a
reference signal based on a periodicity of the reference
signal.
10. The WTRU of claim 1, wherein the first RLF criterion comprises
at least one of: the WTRU entering a light connected state, and
activating a MAC channel.
11. The WTRU of claim 1, wherein the processor is configured to
perform the recovery action further based on at least one of: a
service affected, a failure criterion, and a failure of a previous
recovery.
12. A method of a wireless transmit/receive unit (WTRU),
comprising: establishing at least a first supervision process and a
second supervision process, each associated with one or more radio
link failure (RLF) criteria and a type of transmission or
communication link between a node and the WTRU, wherein each of the
established supervision process is further associated with at least
one of: a bandwidth part (BWP), a beam process, a control channel,
and a quality of service (QoS); determining that a first RLF
criterion associated with a first supervision process of the
established supervision processes has been met; and performing a
recovery action associated with the first supervision process, in
response to a determination that the first RLF criterion has been
met, based on an identity of the first supervision process and a
status of at least the second supervision process.
13. The method of claim 12, wherein each of the established
supervision processes comprises monitoring a predefined reference
signal.
14. The method of claim 12, wherein the type of transmission or
communication link is associated with a control channel or a
grant-less resource.
15. The method of claim 12, wherein each of the established
supervisory processes comprises monitoring at least one signal
characteristic of the type of transmission or communication link or
at least one beam characteristic.
16. (canceled)
17. The method of claim 15, wherein the at least one signal
characteristic comprises at least one of: an average packet delay,
signal quality, an average number of transmission attempts, one or
more cycle redundancy check (CRC) failures, an average data rate,
and a link quality considering interference.
18. The method of claim 15, wherein the at least one beam
characteristic comprises at least one of: a quality metric, an
interference metric, a beam status, a transmission activity
associated with a beam, and a reception activity associated with a
beam.
19. The method of claim 12, wherein the recovery action comprises
at least one of: triggering beam training, triggering a different
transmission type, triggering a different transmission time
interval, and changing the transmission time interval.
20. (canceled)
21. The method of claim 12, wherein the first RLF criterion
comprises at least one of: the WTRU entering a light connected
state, and activating a MAC channel.
22. (canceled)
23. The WTRU of claim 1, wherein each of the established
supervisory processes comprises monitoring a received quality of a
downlink feedback channel associated with a grant-less resource or
one or more transmission attempts.
24. The method of claim 12, wherein each of the established
supervisory processes comprises monitoring a received quality of a
downlink feedback channel associated with a grant-less resource or
one or more transmission attempts.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S.
Provisional Application Ser. No. 62/373,071, filed Aug. 10, 2016,
which is hereby incorporated by reference herein.
BACKGROUND
[0002] Mobile communications continue to evolve. A fifth generation
may be referred to as 5G.
SUMMARY
[0003] Systems, methods, and instrumentalities are disclosed for
connectivity supervision and recovery. A WTRU may supervise its
capability to transmit and receive data, including in the absence
of a control channel (e.g., grant-less transmission). A supervision
framework may permit a WTRU to supervise, for example, quality of a
feedback channel, quality of reciprocal resources and/or
transmission attempts. The WTRU may be configured to take one or
more of a plurality of recovery actions depending on the conditions
related to a plurality of supervision processes.
[0004] A supervision process may be a function of a control channel
structure (e.g., single or multiple control channels, hierarchical
or independent control channels). A WTRU may monitor, for example,
the reliability of a control channel (e.g., using a reference
signal associated with the control channel), a quality of the data
channel scheduled by the control channel, and/or a quality of a
dependent control channel.
[0005] A supervision process may be associated with a quality of
service. A WTRU may monitor one or more supervision processes based
on expected quality of services, such as in a multi-connectivity or
a light connectivity scenario.
[0006] A supervision process may be a function of a WTRU state or
conditions, such as one or more of indemnity or type of a control
channel being monitored by the WTRU, a capability of data transfer
for the WTRU, types of channels utilized by the WTRU, measurements
and/or availability of reference signals in a state.
[0007] A supervision process may be based on WTRU transmission for
energy/resource efficient operation in a dense deployment. A
supervision process may be associated with a control function, MAC
instance, layer, or radio interface.
[0008] Multiple Recovery procedures may be defined. A recovery
procedure may be a function of a supervision process. For example,
one or more recovery procedures may be defined or configured for
low latency services.
[0009] Recovery procedures may involve, for example, dedicated
resources for recovery, transition to a light connection and/or a
grant-less resource. User plane recovery may involve, for example,
re-use of Layer 2 context and/or data replication to companion MAC
instances. A control plane recovery may use, for example, RAN
paging and/or WTRU triggered multi-connectivity. A recovery
procedure for a supervision process associated with a beam process
may include WTRU triggering beam training/beam refinement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is a system diagram illustrating an example
communications system in which one or more disclosed embodiments
may be implemented.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] FIG. 2 is an example of a supervisory process.
[0015] FIG. 3 is an example of a supervisory process.
[0016] FIG. 4 is an example of a supervisory process.
DETAILED DESCRIPTION
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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).
[0023] 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).
[0024] 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).
[0025] 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).
[0026] 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., a eNB and a
gNB).
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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).
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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 139 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)).
[0042] FIG. 1C 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.
[0043] 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.
[0044] 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. 1C, the
eNode-Bs 160a, 160b, 160c may communicate with one another over an
X2 interface.
[0045] The CN 106 shown in FIG. 1C 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.
[0046] 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.
[0047] The SGW 164 may be connected to each of the eNode Bs 160a,
160b, 160c in the RAN 104 via the Si 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.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] In representative embodiments, the other network 112 may be
a WLAN.
[0052] 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.
[0053] 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.
[0054] 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.
[0055] 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).
[0056] 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).
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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).
[0061] 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).
[0062] 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.
[0063] 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.
[0064] 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.
[0065] 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.
[0066] 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 UE 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.
[0067] 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.
[0068] 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 N6interface between the UPF 184a, 184b and the DN 185a,
185b.
[0069] 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-ab,
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.
[0070] 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.
[0071] 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.
[0072] An air interface, e.g., for a new radio (NR) access
technology in a 5G system, may support a variety of use cases, such
as improved broadband performance (IBB), Industrial control and
communications (ICC) and vehicular applications (V2X) and Massive
Machine-Type Communications (mMTC). A next generation air interface
(e.g., 5G air interface) may be configured to allow communications
associated with multiple use cases to be implemented within the
communication system.
[0073] An air interface may support, for example, ultra-low
transmission latency (LLC), ultra-reliable transmission (URC) and
MTC operation (including narrowband operation).
[0074] Support for ultra-low transmission latency (LLC) may
comprise, for example, air interface latency such as a 1 ms (or
less) round trip time (RTT) and/or transmission time intervals
(TTIs) between 100 .mu.s and 250 .mu.s. Support may be provided for
ultra-low access latency (e.g., time from initial system access
until the completion of the transmission of the first user plane
data unit). End-to-end (e2e) latency less than 10 ms may be
supported, for example, for ICC and V2X applications.
[0075] Support for ultra-reliable transmission (URC) may comprise,
for example, improved transmission reliability, such as 99.999%
transmission success and service availability. Support may be
provided for mobility speed in the range of 0-500 km/h. Packet Loss
Ratio of less than 10e.sup.-6 may be supported, for example, for
ICC and V2X applications.
[0076] Support for MTC operation may comprise, for example, air
interface support for narrowband operation (e.g., using less than
200 KHz), extended battery life (e.g., up to 15 years of autonomy)
and minimal communication overhead for small and infrequent data
transmissions (e.g., low data rate in the range of 1-100 kbps with
access latency of seconds to hours).
[0077] A 5gFLEX system may be implemented using orthogonal
frequency division multiplexing (OFDM) and/or other waveforms for
uplink and/or downlink. 5gFLEX system may be a term used to refer
to a wireless communication systems designed to implement the
various use cases using a common or shared radio interface. A
5gFLEX system may correspond to a 5G New Radio (NR) system.
Description of examples herein are meant to be non-limiting to
their specific embodiment and as such these examples may be
applicable and adaptable to other waveforms and wireless
technologies.
[0078] OFDM may be used as a signal format for data transmissions
(e.g., in LTE and IEEE 802.11). OFDM may efficiently divide
spectrum into multiple parallel orthogonal sub-bands. A (e.g.,
each) subcarrier may be shaped using a rectangular window in the
time domain, which may lead to sinc-shaped subcarriers in the
frequency domain. OFDMA may rely on relatively precise frequency
synchronization and tight management of uplink timing alignment
within the duration of the cyclic prefix, for example, to maintain
orthogonality between signals and to minimize inter-carrier
interference. Stringent synchronization requirement may be
difficult to implement in some scenarios, for example, in a system
where a WTRU may be simultaneously connected to multiple access
points. Additional power reduction may be applied to uplink
transmissions, for example, to comply with spectral emission
requirements for adjacent bands. Fragmented spectrum may be
aggregated for WTRU transmissions.
[0079] OFDM (cyclic prefix based OFDM or CP-OFDM) performance may
be improved, for example, by more stringent RF requirements for
implementations, such as operation using a large amount of
contiguous spectrum that may not utilize aggregation. A CP-based
OFDM transmission system may provide a downlink physical layer for
5G similar to a 4G system with modifications to pilot signal
density and location.
[0080] 5gFLEX radio access may be characterized by a very high
degree of spectrum flexibility that enables deployment in different
frequency bands with different characteristics, which may include
different duplex arrangements, different and/or variable sizes of
available spectrum, such as contiguous and non-contiguous spectrum
allocations in the same or different bands with same or different
frequency location within a frequency band. 5gFLEX radio access may
support variable timing aspects, such as support for multiple TTI
lengths and asynchronous transmissions.
[0081] Multiple duplexing schemes (e.g., time division duplexing
(TDD), frequency division duplexing (FDD), etc.) may be supported.
Supplemental downlink operation may be supported, e.g., for FDD
operation, for example, using spectrum aggregation. FDD operation
may support full-duplex FDD and half-duplex FDD operation. DL/UL
allocation may be dynamic (e.g., may not be based on a fixed DL/UL
frame configuration), e.g., for TDD operation. The length of a DL
or a UL transmission interval may be set per transmission
opportunity.
[0082] A WTRU may be configured to receive and/or detect one or
more system signatures. A system signature may consist of a signal
structure using a sequence. A signal may be similar to a
synchronization signal e.g., similar to NR-SS, e.g., similar to LTE
PSS and/or SSS. A signature may be specific to (e.g., may uniquely
identify) a particular node (or transmission/reception point (TRP))
within a given area or it may be common to a plurality of nodes (or
TRPs) within an area, which aspect may not be known and/or relevant
to a WTRU. A WTRU may determine and/or detect a system signature
sequence and may further determine one or more parameters
associated with the system. For example, a WTRU may further derive
an index therefrom and may use the index to retrieve associated
parameters, e.g., within a table, such as an access table. For
example, a WTRU may use received power associated with a signature
for open-loop power control, e.g., to set an initial transmission
power when a WTRU determines that it may access (and/or transmit)
using applicable resources of the system. For example, a WTRU may
use the timing of a received signature sequence, e.g., to set the
timing of a transmission (e.g., a preamble on a PRACH resource)
when the WTRU determines that it may access (and/or transmit) using
applicable resources of the system.
[0083] A system signature may consist of any type of signal
received by a WTRU for one or more purposes described herein.
[0084] A WTRU may be configured with a list of one or more entries.
A list may be referred to as an access table. A list may be
indexed, e.g., where an (e.g., each) entry may be associated with a
system signature and/or to a sequence thereof An access table may
provide initial access parameters for one or more areas. An (e.g.,
each) entry may provide one or more parameters used for performing
an initial access to the system. Parameters may include one or more
of a set of one or more random access parameters (e.g., including
applicable physical layer resources, such as PRACH resources) in
time and/or frequency, initial power level and/or physical layer
resources for reception of a response. Parameters may (e.g.,
further) include access restrictions (e.g., PLMN identity and/or
CSG information). Parameters may (e.g., further) include
routing-related information, such as one or more applicable routing
areas. An entry may be associated with (and/or indexed by) a system
signature. An such entry may be common to a plurality of nodes (or
TRPs). A WTRU may receive an access table, for example, via a
transmission using dedicated resources (e.g., by RRC configuration)
and/or by a transmission using broadcast resources. In the latter
case, the periodicity of the transmission of an access table may be
relatively long (e.g., up to 10240 ms), which may be longer than
the periodicity of the transmission of a signature (e.g., in the
range of 100 ms).
[0085] An access table may consist of any type of system
information received by a WTRU for one or more purposes described
herein.
[0086] A radio access network (RAN) slice may consist of (e.g.,
all) radio access network functions and transport network functions
and resources, e.g., radio resources and backhaul/fronthaul
resources along with core network functions/resources that may be
used or required to provide end-to-end services to a user. Network
functions may, for example, be virtualized on a general-purpose
processor, run as network functions on specialized hardware or
split between specialized hardware and general purpose hardware. A
PLMN may consist of one or more network slices. A slice may be
similar to an operator's single, common or general purpose network.
A RAN slice may consist of one or more Spectrum Operating Modes
(SOMs) that may be optimized to support various services that the
RAN slice may have to offer.
[0087] In an example, a SOM may correspond to a bandwidth part
(BWP). The WTRU may be configured with one or more bandwidth part
(BWP). For example, a BWP may consist of a group of one or more
contiguous physical resource blocks (PRBs). For example, the
configuration of a BWP may include a numerology (e.g., including
sub-carrier spacing, symbol time duration), a frequency location
(e.g., a center frequency) and a bandwidth (e.g., a number of
PRBs). The configuration of a downlink BWP may include at least one
CORESET. The WTRU may be configured with a default BWP e.g., used
when performing initial system access or when performing a recovery
procedure for a given cell or carrier.
[0088] The WTRU may be configured with one or more CORESETs. A
CORESET may consist of a number of resource blocks in the frequency
domain and a number of symbols in the time domain (e.g., 1, 2 or 3
symbols). A physical downlink control channel (PDCCH) may be
associated with a CORESET. The WTRU may receive downlink control
signaling (DCI) on a CORESET.
[0089] In an example, WTRUs served within a slice may have, for
example, one or more of the following aspects in common: (i)
services and/or QoE requirements (e.g., ULLRC, eMBB, MMTC); (ii)
WTRU categories (e.g., CAT 0 to M and beyond, additional categories
may be defined for >6 GHz to differentiate beamforming
capability); (iii) coverage requirements (e.g., normal coverage,
enhanced coverage); (iv) PLMN/Operators; (v) support for a specific
Uu interface (e.g., LTE, LTE-Evo, 5G below 6 Ghz, 5G above 6 Ghz,
Unlicensed) and/or (vi) served by the same core network slice. The
terms "RAN slice" and "slice" may be used interchangeably.
[0090] Functions and components supporting an NR system may be
logically grouped, for example, in terms of an Edge Control/Access
Plane (AP), a Central Control Plane (CCP) and a Central User Plane
(CUP). Logical grouping may enable different components and
functions of the system to be isolated from each other. Isolation
may enable components and functions to be controlled, configured,
modified and/or operated separately from each other. Separation may
be applied for components and functions associated with a specific
WTRU, per TRP/NR-eNB, per TRP group (TRPG), per TRPGs, per group of
NR-eNBs, per logical channel (LCH) (or equivalent), per slice or
the like. Further separation between centralized and access-related
grouping may enable coordination between different instances of a
function (e.g., system information provisioning, bearer
configuration) or between different instances of different
functions (e.g., core network connectivity and user plane/bearer
instances). An edge control function may be associated with a
scheduler instance. A WTRU may be configured to associate a
specific signaling bearer (e.g., a transport path/method) for
control of a MAC entity with the concerned MAC entity. A function
may (e.g., alternatively) use the transport services of MAC
protocols (e.g., as MAC Control Elements) or similar. Central
Control Functions (e.g., RAN central control functions) may include
functions, protocols and/or context that may be WTRU specific
and/or applicable to one or more TRPs/edge control functions. A
central control plane may be considered to be an anchor control
function that may terminate the control interface towards the core
network (e.g., through the configuration/setup of routing paths and
transport paths, which may, for example, be based on tuples
configured for the WTRU). A central control function may (e.g.,
additionally) include control functions related to selection of a
core network slice, CN-RAN interfaces, QoS management, security
(e.g., master key management and key derivation, which may be per
group of TRPs/NR-eNBs), WTRU capability management, and/or WTRU
reachability within a RAN.
[0091] LTE radio link monitoring may involve monitoring a downlink
(DL) radio link condition of a serving cell. A WTRU may monitor
downlink radio quality against thresholds (e.g., Qout and Qin) for
a (e.g., every) frame or DRX period, for example, depending whether
DRX may be activated. A physical layer may indicate in-sync or
out-of-sync to higher layers (e.g., radio resource control (RRC)),
for example, when radio link quality may be better than Qin or
worse than Qout (respectively). Threshold Qout may be defined as a
level at which downlink radio link may not be reliably received and
may correspond to a (e.g., 10%) block error rate of a hypothetical
physical downlink control channel (PDCCH) transmission, e.g.,
taking into account physical control format indicator channel
(PCFICH) errors. Threshold Qin may be defined as a level at which
downlink radio link quality may be (e.g., significantly) more
reliably received than at Qout and may correspond to a (e.g., 2%)
block error rate of a hypothetical PDCCH transmission, e.g., taking
into account PCFICH errors. A WTRU (e.g., upon reception of N310
consecutive out-of-sync indications) may detect that a physical
layer problem has occurred and may start a recovery timer T310. A
WTRU (e.g., when the timer expires before the N311 consecutive
in-sync indications may be received ("recovery of physical layer
problem")) may declare that a radio link failure has occurred. A
radio link failure may trigger a WTRU to suspend (e.g., all) a
radio bearer, reset the MAC, apply default PHY and MAC
configuration, and/or perform cell selection. A WTRU (e.g., when a
suitable cell may be found before timer expiration) may perform RRC
connection re-establishment. A WTRU (e.g., when a suitable cell may
not be found before timer expiration) may give up recovery of the
connection and go to IDLE state.
[0092] Next generation air interfaces (e.g., including further
evolution of LTE Advanced Pro and a New Radio (NR)) may support a
wide range of use cases with varying service requirements (e.g.,
low overhead and low data rate power efficient services such as
massive machine type communications (mMTC) services, ultra-reliable
low latency communications (URLLC) services, and high data rate
enhanced mobile broadband (eMBB) services) for diverse WTRU
capabilities (e.g., low power and low bandwidth WTRUs, WTRUs
capable of very wide bandwidth (e.g., 80 Mhz), WTRU support for
high frequencies (e.g., >6 Ghz), etc.) under various mobility
scenarios (e.g., stationary/fixed, high speed trains, etc.) using
an architecture that may be flexible enough to adapt to diverse
deployment scenarios (e.g., centralized, virtualized, distributed
over ideal/non-ideal backhaul etc.).
[0093] A WTRU may monitor aspects (e.g., measurements) to stay in
connected state. Criteria associated with measurements may need to
be satisfied by a WTRU for continued operation in connected state.
A WTRU may monitor its capability to be scheduled, e.g., by
verifying that BLER associated with a PDCCH channel may be above a
predefined threshold. An NR radio link monitoring procedure may,
for example, account for control channel structure, characteristics
of one or more control channel types, transmission aspects of the
control channel (e.g., beamforming, possibility of multiple
numerologies), etc.
[0094] An NR radio link may designed to attempt to avoid service
interruption. For example, an NR radio link may attempt to achieve
a 0 ms mobility interruption time. A mobility interruption time
requirement may be for network controlled mobility (e.g.,
handover). Service interruption may (e.g., also) be attempted to be
reduced in cases of link failure, for example as compared to RLF in
LTE systems.
[0095] In LTE systems WTRU, the WTRU may have had to perform
multiple steps to recover from Radio Link Failure (RLF) while in a
connected state. The recovery may include, for example, releasing
configured resources, transitioning to idle mode, executing a cell
selection, initiating contention based random access, waiting for
contention resolution and performing a layer 3 procedure such as a
re-establishment procedure. Data transmission to/from a WTRU may
have been interrupted during radio link recovery. A WTRU may have
not resumed data transfer, for example, until (e.g., all) recovery
steps were completed. Such data interruption can negatively affect
a quality of experience by an end user. Such service interruption
for a radio link failure for services such as URLLC applications
may lead to intolerable service interruption times for the
application.
[0096] In some deployments, there may be an absence of a regular
control channel during data transfer, for example associated with a
grant-free/grant-less access. Grant-free/Grant-less access may
reduce overhead associated with network access and with providing
grants before transmissions. Grant-free access may be used to speed
up access, for example, when moving from inactive to active state,
e.g., by eliminating the need to access a channel, request
resources and wait for a grant. Monitoring may be provided for
capabilities of grant-less access.
[0097] In some deployments, there may be an absence of a periodic
reference signal for monitoring. A radio link monitoring process
(e.g., in LTE) may rely on presence of cell specific reference
signals that may be (e.g., always) transmitted. The
location/placement of reference signals may span (e.g., complete)
system bandwidth. A lean carrier approach (e.g., for 5G NR) may
confine transmissions in time, frequency and space. Monitoring may
be provided for a radio link that may take into account a lack of
always-on signals.
[0098] A diverse quality of service may be offered by next
generation air interfaces. A WTRU may monitor link quality, whether
active flows/services/bearers may be served as per expectations,
(e.g., where a WTRU may be served by multiple schedulers, such as
for multi-connectivity, and/or for light connectivity).
[0099] A relation may exist between supervision procedure and WTRU
states. An LTE WTRU may have two states (e.g., IDLE or CONNECTED
states). An LTE WTRU may perform radio link monitoring in CONNECTED
state and may move to idle state upon link failure. NR may have one
or more additional states (e.g., a RAN controlled state, light
connected state, connected state with WTRU autonomous mobility,
etc.). Supervision may be performed in multiple states and
different supervision criteria may be applicable to different
states. Different recovery actions may be dependent on the
supervision criteria and/or the state. For example, state
transitions may occur in case of failures while in certain
states.
[0100] One or more connectivity supervision processes and recovery
procedures based on the supervision processes may be used. A
supervision process may be used to monitor a supervision signal. A
supervision signal may include one or more predefined
signals/sequences and/or aspects of physical transmission that may
provide a reference for a supervision procedure. A supervision
signal may or may not be a dedicated signal transmitted solely for
the purpose of supervision.
[0101] A WTRU may consider one or more signals from a TRP as a
supervision signal. A signal may be a reference signal, for
example, such as a cell specific reference signal, a transmission
point specific reference signal, a BWP specific reference signal
(e.g., a NR-SS), a synchronization signal (e.g., such as primary
synchronization signal (PSS)/secondary synchronization signal
(SSS)), a low duty cycle signal such as a discovery reference
signal (e.g., DRS) and/or a reference signal associated with a
position reference (e.g., a positioning reference signal (PRS)). A
signal may be a combination of a plurality of signals e.g., a SS
block, for example, such as a combination of a least one of a PSS,
a SSS and a Physical Broadcast Channel (PBCH). A signal may include
multiple occurrences of a signal, for example one or multiple SS
blocks corresponding to a SS burst. A signal may be a signature
associated with one or more transmission points (e.g., a system
signature). A WTRU may consider a downlink transmission whose
presence and characteristics (e.g., sequence and resource mapping)
may be known apriori as a supervision signal.
[0102] One or more control channels that belong to the same or
different control channel type may be used in a cell. A control
channel type may be characterized by one or more aspects alone or
in any combination.
[0103] A control channel type may be characterized, for example, by
resources that may be used for control channel transmission, such
as time/frequency resources occupied by the control channel,
subframe type, duration of the control channel, placement in the
resource grid, bandwidth occupied, number and/or nature of
aggregation of smaller resource groups, spectral operating mode,
and/or the like.
[0104] A control channel type may be characterized, for example, by
a traffic type of an associated data channel, such as a service
type (e.g., eMBB, URLLC, mMTC, etc.), association of a control
channel to a specific slice, etc. For example, different control
channels may be defined for different services.
[0105] A control channel type may be characterized, for example, by
the information carried in the control channel, such as partial or
complete scheduling information or an index to a predefined
schedule carried in the control channel, WTRU identity used in the
control channel, etc.
[0106] A control channel type may be characterized, for example, by
a reference signal associated with the control channel, such as a
cell specific reference signal, control channel specific reference
signal or other type of reference signal associated with the
control channel, preamble associated with the control channel,
etc.
[0107] A control channel type may be characterized, for example, by
spatial/beamforming characteristics, such as an extent of spatial
filtering (e.g., cell wide, wide beam, narrow beam control
channel), number of antenna ports, antenna port number, type of
beamforming used (analog, digital or hybrid), etc.
[0108] A control channel type may be characterized, for example, by
a WTRU category that may receive or monitor the control channel,
such as WTRUs with limited bandwidth/complexity that may monitor a
specific type of control channel.
[0109] A control channel type may be characterized, for example, by
a search space associated with a control channel, such as a
location of a control channel that may be known apriori (e.g., an
explicit control channel) or an approximate location where a WTRU
may blind decode the control channel.
[0110] A control channel type may be characterized, for example, by
WTRUs monitoring the control channel, such as whether a control
channel is visible to all or a subset of WTRUs in a cell or
dedicated to a specific WTRU, etc.
[0111] A control channel type may be characterized, for example, by
a purpose for a control channel, such as scheduling grants (e.g.,
schedule a data channel, schedule another control channel, schedule
discontinuous transmission (DTX) of the TRP, schedule reference
signal, etc.), DL hybrid automatic repeat request (HARQ) feedback,
indicate type of frame/sub-frame, trigger signal/preamble
transmission from WTRU, indicate presence/absence of other
channels/signals or carry any other DL control information.
[0112] A control channel type may be characterized, for example, by
scheduling periodicity of a control channel (e.g., periodic or
on-demand).
[0113] A control channel type may be characterized, for example, by
a time/frequency relation to the associated data channel.
[0114] A control channel type may be characterized, for example, by
association to a transmission point or a group of transmission
points.
[0115] A control channel type may be characterized, for example, by
applicability and validity of received information in the control
channel, such as whether received information is applicable in the
same TTI as a received control channel or applicable at a specific
offset, valid for one TTI, valid for a number of TTI and/or valid
until explicitly modified/failure.
[0116] A control channel type may be characterized, for example, by
independence of a control channel, such as whether a control
channel may be standalone or may used in conjunction with another
control channel. A control channel may be multiplexed with a data
channel.
[0117] A control channel type may be characterized, for example, by
any other transmission characteristics of the control channel, such
as modulation/coding, transmit power, spreading, waveform,
subcarrier spacing, symbol length, CP length/content, scrambling
sequence, etc.
[0118] One or more aspects of control channels may be applicable in
uplink, sidelink and/or self-backhaul/fronthaul links.
[0119] A beam process may be characterized by a set of beamforming
parameters/configuration for a spatially filtered transmission
and/or reception. A beam process may be characterized by the
state/contextual information associated with the transmission
and/or reception of the beamformed transmission. A beam process may
include or be characterized by, for example, one or more of the
following: precoding weights, power, timing,
associated/configured/assigned/selected reference signal sequence,
number of antenna port(s), antenna port number, type of beamforming
(e.g., analog, digital or hybrid), channel state associated with
beam process, a linkage between a transmit and receive beam, a set
of triggers/timers/feedback associated with a beam process, an
identity of one or more transmission points associated with a beam
process, a configuration of beam sounding signal, etc.
[0120] A beam process may be used to simplify signaling of beam
characteristics between a WTRU and an eNB. A WTRU may be configured
with one or more beam processes. A (e.g., each) beam process may be
associated with a beam process identity.
[0121] A WTRU may be configured to performed supervision
measurement(s) and detect one or more types of radio failure based
on the supervision measurement(s). A Supervision Process (SP) may
be characterized by a procedure by which the WTRU performs
monitoring of one or more resources (e.g., reference signals,
control channels, etc.) according to a set of configuration
parameters and/or rules. A supervision process may include set of
contextual information and/or state of monitoring activity. A WTRU
may have zero or one or more supervision processes instantiated at
any point in time. WTRU actions may be determined by a comparison
of the status of a supervision process against a (pre-) defined or
configured criteria. Supervision failure may be declared, for
example, when a supervision process fails to meet the criteria.
Different type of recovery actions may be performed depending on
which supervisory process fails to meet its predefined or
configured criteria.
[0122] A supervision procedure may be performed, for example, at
layer 3 (e.g., RRC) and/or layer 1 (e.g., PHY), e.g., based on
measurements from layer 1 and/or based on events observed at layer
1 and/or layer 3. A supervision process that depends on
transmissions from the network may (e.g., also) be referred as a
reception based supervision process.
[0123] A supervision process may be designed to ensure that the
WTRU is capable of transmitting and/or receiving data, for example
a certain type of data specific to the supervision process. For
example, a WTRU may perform data transfer on grant-less resources
that may not require a regular control channel. A supervision
process may be defined to monitor one or more aspects of WTRU
capability to transmit and receive data, e.g., including data
transfers on grant-free resources.
[0124] A WTRU may instantiate a supervision process for grant-free
resources based on one or more events alone or in any combination.
For example, a WTRU may instantiate a supervision process upon
arrival of a UL data that may be mapped to grant-less traffic
according to packet forwarding treatment (e.g., based on size of
data packet data unit (PDU), type of data PDU, service type). A
WTRU may instantiate a supervision process if the WTRU has not
received a valid grant and has packet latency that may be below
budget. A WTRU may instantiate a supervision process upon entering
a cell that may support grant-less access. A WTRU may instantiate a
supervision process when a WTRU gets configured with grant-less
resources. A WTRU may instantiate a supervision process when an
access class broadcasted from the cell allows for grant-less
access. A WTRU may instantiate a supervision process when
segmentation may not be allowed and a received grant may not be
large enough for transmission of a whole PDU. A WTRU may
instantiate a supervision process when a supervision process for a
downlink control channel fails and a WTRU may fall back to using
grant-less resources and instantiate a supervision process
associated with grant-less access. A WTRU may instantiate a
supervision process when a WTRU loses UL synchronization or upon a
timing alignment timer TAT expiration and characteristics of
grant-less resources allow for non-orthogonal and asynchronous
transmission. A WTRU may instantiate a supervision process) when a
maximum number of RACH retransitions has been reached before a
successful response. A WTRU may instantiate a supervision process
upon handover failure where reestablishment may be triggered. A
WTRU may instantiate a supervision process when a network may be in
DTX (e.g., not transmitting control channels).
[0125] A WTRU may supervise aspects associated with grant-free
transmission. For example, a supervision process may monitor one or
more of: (i) quality of feedback channel, (ii) quality of
reciprocal resources and/or (iii) the number of transmission
attempt(s). A WTRU may monitor one or more of the aspects alone or
in any combination. A WTRU may be configured to declare supervision
failure when one or more (e.g., all) of the criteria fail. For
example, WTRU may be configured to declare supervision failure a
quality of feedback channel falls below a threshold, a quality of
reciprocal resources falls below a threshold, and/or a number of
transmission attempt(s) exceeds a threshold.
[0126] A supervised aspect associated with grant-free transmission
may include a quality of a feedback channel. A WTRU may monitor the
received quality of a downlink feedback channel associated with a
grant-free UL transmission. A (e.g., each) downlink feedback
channel may be associated with a (e.g., unique) reference signal. A
WTRU may determine a quality of the downlink feedback channel using
the measurements over the associated reference signal. A reference
signal may be cell specific, WTRU specific or may be dedicated for
grant-free transmission feedback. In an example, a reference signal
associated with a feedback channel may be a demodulation reference
signal. A WTRU may (e.g., only) consider measurements performed in
a spectral region and bandwidth associated with downlink feedback
resources, which may be a subset of whole system bandwidth. A WTRU
may obtain a configuration of DL feedback resources and associated
reference signal configuration, for example, in one or more of the
following ways: (i) in a cell specific broadcast, WTRU specific
signaling, area specific signaling via access table or using a
predefined relation (e.g., with respect to UL resources used for
grant-free transmission). A WTRU may declare a supervision failure,
for example, when the quality of a feedback channel may be below a
predefined threshold during a period longer than a predefined
duration.
[0127] A supervised aspect associated with grant-free transmission
may include a quality of reciprocal resources. A WTRU may monitor
the received quality of a downlink reference signal within a DL
spectral region. A DL spectral region may be associated with the UL
spectral region used for grant-less transmission. A WTRU may assume
reciprocity of DL and UL resources (e.g., for TDD mode of
deployment). In an example, a reference signal within a DL spectral
region may be used for other purposes, e.g., for synchronization,
positioning, discovery, etc. A WTRU may declare a supervision
failure, for example, when the quality of reciprocal resources may
be below a predefined threshold during a period longer than a
predefined duration.
[0128] A supervised aspect associated with grant-free transmission
may include a transmission attempt. A WTRU may monitor a number of
transmission attempts made on grant-free resources before a
feedback (ACK or NACK) was received. WTRU UL transmission may fail,
for example, due to a poor UL channel, due to contention/collision
with other WTRU transmissions or due to loss of feedback message.
In an example, a WTRU may monitor a (e.g., an average) number of
transmission attempts before a successful transmission is made
during a predefined time window. A WTRU may declare a supervision
failure, for example, when the number of transmission attempts may
be more than a value N for more than M times during a time interval
T, where N, M and T may be predefined/preconfigured.
[0129] A supervision process may be a function of control channel
structure. A WTRU may associate multiple supervision processes with
a single control channel. A purpose for a (e.g., each) supervision
process may be to monitor one or more specific aspects associated
with a control channel. A WTRU may monitor a (e.g., single) control
channel for multiple purposes. For example, WTRUs in a light
connected state may monitor a control channel for a RAN paging,
which may be limited to certain control message types and/or
control regions within the control channel. For example, WTRUs that
may need enhanced coverage may require repetition of the same
control channel for a successful reception of a downlink control
message. For example, a WTRU may monitor a control channel for a
complete scheduling grant or for a fast scheduling grant that may
be a few bits long and may activate one or more preconfigured
grants. A supervision process may monitor WTRU capability, for
example, to receive a specific control message according to a use
case and/or type of service.
[0130] A WTRU may monitor multiple control channels belonging to
one or more control channel types from a network. In an example,
multiple control channels may be seen as different regions,
different blind decoding configurations, different aggregation of
resources, and/or different formats of messages in the same
physical control channel. In an (e.g., another) example, a WTRU may
monitor two or more control channels with different numerology
(e.g., with different symbol length, sub-frame duration, cyclic
prefix length, subcarrier spacing, etc.). Control channels may be
multiplexed in frequency and/or time. A control channel with a
specific numerology may be associated with a dedicated reference
signal and may be used for a specific service or purpose. A WTRU
may monitor two or more control channels. A (e.g., each) control
channel may carry control messages/signals that may be associated
with a service.
[0131] A WTRU may associate at least one supervision process with
each monitored control channel. Multiple supervision processes may
be active in a WTRU at a given time. A purpose of a (e.g. each)
supervision process may be to ensure that a WTRU can reliably
receive the corresponding control channel.
[0132] Interaction between two or more supervision processes (e.g.
at a WTRU) may be a function of relation between the associated
control channels.
[0133] Control channels may be independent. Independence may
include one or more of the following: (i) presence of a control
channel may not be determined by another control channel and/or
(ii) information content in a control channel may be
self-sufficient (e.g. may provide a complete scheduling grant or
other control message).
[0134] A WTRU may associate an independent supervision process with
a monitored independent control channel. In an example, a WTRU may
be configured with an active control channel and a backup control
channel. A WTRU may instantiate a supervision process associated
with a backup control channel, for example, based on a status of a
supervision process associated with an active control channel.
[0135] Control channels may be dependent. Dependence may include
one or more of the following: (i) presence of a control channel may
be determined by (e.g. implicit) presence of another control
channel, (ii) presence of a control channel may be determined by a
control message that may be received in another control channel
and/or (iii) information content in a control channel may be
combined (e.g. by a WTRU) with information from another control
channel to obtain a complete control message or scheduling
information.
[0136] In an example, dependent control channels may be
hierarchical, e.g., a WTRU may acquire the control channel higher
in a hierarchy to acquire the control channel lower in the
hierarchy. A WTRU may infer the status of control channel as lower
in the hierarchy, for example, based on a status of a supervision
process associated with the control channel higher in the
hierarchy.
[0137] A supervision process associated with a control channel may
monitor one or more of the following: (i) reliability of a control
channel, (ii) quality of a data channel scheduled by a control
channel and/or (iii) reliability of a dependent control
channel.
[0138] A supervision process may monitor a reliability of a control
channel. A supervision process associated with a control channel
may monitor the reliability of the control channel. A WTRU may
determine a capability to receive a control channel, for example,
based on an expected Block Error Rate of the control channel. A
reference signal associated with a control channel may not span the
whole bandwidth. A WTRU may monitor multiple control channels. A
(e.g. each) supervision process may utilize measurements of a
reference signal associated with the corresponding control channel.
For example, a reference signal and its associated control channel
may be transmitted over a same spectral region or part of a
resource grid multiplexed in time, frequency and/or code. A WTRU
may (e.g. when determining the BLER) consider message sizes/formats
that may be expected to be received in the control channel or
control channel type. A WTRU may declare a supervision failure, for
example, when the quality of a reference signal associated with a
supervised control channel may be below a predefined threshold
during a period longer than a predefined duration.
[0139] A supervision process may monitor a quality of data channel
scheduled by a control channel. A control channel may be allowed
to/have a capability to schedule (e.g. specific) portions of a
resource grid (e.g., a spectral region or a subset of the whole
bandwidth). A WTRU may monitor, for example, control channel
quality and/or quality of spectral region associated with the data
channel scheduled by the control channel. A WTRU may determine a
quality of a data channel, for example, by measuring a reference
signal associated with a data channel (e.g., a demodulation
reference signal). A WTRU may determine a quality of a data
channel, for example, by a number of retransmissions and/or a
number of NACKs transmitted. A WTRU may declare a supervision
failure, for example, when a reference signal associated with the
data channel may be below a predefined threshold or when a number
of NACKs may be above a predefined threshold.
[0140] A supervision process may monitor a reliability of a
dependent control channel. Reliability of a first control channel
may be a function of reliability of a second control channel. A
supervision process associated with a first control channel may be
linked to another supervision process associated with a second
control channel. A WTRU may trigger a supervision of an independent
control channel, for example, when a dependent control channel
reliability falls below a threshold.
[0141] A WTRU may instantiate a supervision process associated with
a control channel, for example, based on one or more of the
following events: (i) when the WTRU starts to read the control
(e.g., when the WTRU starts to monitors the control channel); (ii)
based on a quality of a dependent channel (e.g., when the
supervision process of a dependent control channel fails to meet a
predefined criteria); (iii) when the WTRU receives the
configuration of a control channel or when a MAC instance
associated with a control channel may be activated; and/or (iv)
when a service associated with a control channel may be
activated.
[0142] A supervision process may be associated with a quality of
service. A WTRU may support diverse services with varying degree of
resilience/tolerance towards degradation in link quality and
interruption. A WTRU may trigger recovery actions at the right
time, e.g., not too early since the link conditions may improve and
not too late since the quality of the link may degrade to
negatively affect a quality of service.
[0143] A flexible configuration for a supervision process may be
defined. In an example, the function and parameterization of a
supervision process may be a function of quality of service. For
example, a WTRU may be configured for a plurality of supervision
processes. A (e.g., each) supervision process may be associated
with a type of service. A supervision process may monitor an
expected quality of service offered to the WTRU, which may include,
for example, monitoring one or more of the following: (i) average
packet delay, (ii) average number of retransmission attempts, (iii)
number of cycle redundancy check ("CRC") failures on a control
channel, (iv) average data rate, and/or (v) quality of a link.
[0144] An average packet delay may be monitored. An average packet
delay may be based on the time when a packet was received at radio
interface protocol layers as compared to a time when a successful
acknowledgement of reception may be received from the network. A
WTRU may declare a supervision failure, for example, when an
average packet delay may be above a predefined threshold.
[0145] An average number of retransmission attempts may be
monitored. An average number of retransmission attempts may be
based on downlink and uplink transmissions. A WTRU may declare a
supervision failure, for example, when the number of retransmission
attempts may be above a predefined threshold.
[0146] A number of CRC failures on a control channel may be
monitored. A WTRU may declare a supervision failure, for example,
when the number of CRC failures on a control channel may be above a
predefined threshold.
[0147] An average data rate (e.g., measured at layer 1 or layer 2)
may be monitored. A WTRU may declare a supervision failure, for
example, when the average data rate may be below a predefined
threshold.
[0148] A quality of a link (e.g., considering interference from
neighbor TRPs (e.g. a SINR metric)) may be monitored. A WTRU may
declare a supervision failure, for example, when the SINR may be
below a predefined threshold.
[0149] A quality of service (QoS) aware supervision process may be
defined, for example, per radio bearer/flow/slice/service or per
transport channel. A QoS supervision process may enable radio level
QoS monitoring (e.g., in a multi-connectivity case), for example,
when a single TRP/scheduler may not have a centralized knowledge of
cumulative quality of service offered to a WTRU. A QoS supervision
process may be applied in a light connected state, for example,
where a WTRU may move (e.g. transparently) between TRPs/schedulers
and a single TRP/scheduler may not be aware of the scheduling
history for a WTRU.
[0150] A supervision process associated with a QoS may be
considered as complementary to scheduling assistance, e.g., similar
to interaction between radio link monitoring and measurement
reporting.
[0151] A supervision process may be associated with a sparse
reference signal. A supervision signal may be sparse in time (e.g.,
may not be transmitted in all subframes and/or with a fixed
periodicity). A supervision signal may be sparse in frequency
(e.g., may not span the whole system bandwidth). A supervision
signal may be sparse in space (e.g., may not be broadcast by all
TRPs all the time). A supervision process may be aware of a sparse
nature of a supervision signal. In an example, a WTRU may adjust
the periodicity of supervision evaluation, for example, as a
function of periodicity of the supervision signal.
[0152] A WTRU may be connected to multiple TRPs in a
multi-connectivity case, e.g., where the WTRU may receive sparse
supervision signal from a (e.g., each) TRP. In an example, the
sparse signal may be a system signature shared by two or more TRPs.
A supervision process may be associated with a system signature,
for example, irrespective of the transmission point. A WTRU may
declare a supervision failure, for example, when a received system
signature may be lower than a predefined threshold.
[0153] In an example, multiple (e.g., two) types of supervision
signals may be defined (e.g., WTRU specific and cell specific). A
WTRU may instantiate a supervision process to monitor a cell
specific supervision signal, for example, upon a failure of a
supervision process associated with a WTRU specific signal.
[0154] A WTRU may receive a sparse supervision signal from a
plurality of TRPs. A WTRU may combine a supervision signal received
from plurality of transmission points, for example, to evaluate the
quality of multi-connectivity. In an (e.g., another) example, a
WTRU may perform measurements for multiple TRPs and may evaluate a
combined measurement result. A combined result may be indicative of
the quality of multi-connectivity.
[0155] A supervision process may be associated with a beamformed
channel. A beamformed channel may be associated with a beam
process, for example, to manage a set of beamforming
parameters/configuration for transmission/reception and
state/contextual information associated with the
transmission/reception. One or more beam processes may be
configured for a WTRU and may be associated with a supervision
process. A supervision process may monitor the suitability of a
beam and may be associated with a measurement history (e.g., a
quality metric, interference metric, status of the beam (active,
inactive, forbidden etc.), transmission/reception activity with the
beam process, etc.). In an example, a (e.g., each) beam process
that may be configured for a WTRU may be associated with a
dedicated supervision process, e.g., to monitor the quality of a
beamformed link. In an (e.g., another) example, a WTRU may
supervise (e.g., only) beam processes associated with a serving
control channel and/or data channel. In an example, a WTRU may
supervise (e.g., only) beam processes that may be active and/or
whose quality may be above a predefined threshold. In an (e.g.,
another) example, a WTRU may be (e.g., explicitly) configured with
a list of beam process that may be supervised, which may include a
set of backup beam processes along with serving beam processes. A
beam process may be associated with a reference signal that may be
specific to a transmit beam. A supervision process may monitor a
reference signal associated with a beam process.
[0156] A WTRU may evaluate its connectivity to a serving TRP, for
example, based on a status of a supervision processes associated
with two or more beam processes. In an example, a set of
supervision processes in a WTRU may differentiate between: (i)
losing a serving data beam associated with a serving TRP, (ii)
losing all data beams associated with a serving TRP, (iii) losing a
serving control beam associated with a serving TRP, and (iv) losing
all control beams associated with a serving TRP.
[0157] Losing a serving data beam associated with a serving TRP may
be based on, for example, a reference signal threshold associated
with a data beam process. A serving data beam may refer to a beam
process actively scheduled.
[0158] Losing all data beams associated with a serving TRP may be
based on, for example, a reference signal threshold associated with
data beam processes.
[0159] Losing a serving control beam associated with a serving TRP
may be based on, for example, a reference signal threshold
associated with a control beam process. A serving control beam may
refer to a beam process monitored by a WTRU to receive DL control
messages/grants.
[0160] Losing all control beams associated with a serving TRP may
be based on, for example, a reference signal threshold associated
with control beam processes. A WTRU may consider this as a
connectivity failure to the serving TRP.
[0161] A WTRU may instantiate multiple supervision processes to
monitor and detect status per TRP/cell and/or to monitor and detect
status per multiple TRPs/cells, e.g., in a multi-connectivity
case.
[0162] A WTRU may instantiate a supervision process for a beam
process based on, for example, the status of a supervision process
associated with a linked beam process. Linkage may mean, for
example, one or more of the following: (i) a relation between a
beam process that may be associated with a control channel and a
beam process that may be associated with a data channel scheduled
by that control channel; (ii) a relation between beam processes
associated with the same serving TRP; and/or (iii) a relation
between beam processes associated with the same receive beam at the
WTRU.
[0163] A supervision process may be a function of a WTRU state. A
WTRU may operate according to multiple states, e.g., idle state,
light connected state (RAN controlled state) and connected
state.
[0164] An idle state may be a low activity/low power state where
radio link supervision may not be a priority. In an example, a WTRU
may instantiate supervision processes to monitor a broadcast
channel and a paging channel.
[0165] A light connected state (RAN controlled state) may permit
(e.g., small) data transfers. A WTRU context may be stored in the
RAN and the RAN-core connection may be maintained. A WTRU may not
have an active connection to the network. A WTRU may instantiate
supervision processes, for example, when performing data
transfers.
[0166] A connected state may be an active state with (e.g., large)
data transfers. A WTRU may have an active connection to the
network. A WTRU may instantiate supervision processes, for example,
when entering the state.
[0167] A supervision process may be a function of WTRU state. A
WTRU may instantiate supervision processes, for example, based on
various characteristics/configurations that may define a state. For
example, supervision processes may be instantiated based on one or
more of the following characteristics associated with a state: (i)
transmission methods/resources (e.g., grant-less, common/shared
resources, dedicated resources), (ii) data transmission throughput,
(iii) neighbor cell measurements and measurement reports, (iv) DRX
cycle and timers, (v) type of channels, (vi) mobility (e.g., WTRU
autonomous or network controlled), (vii) paging area (e.g., cell,
RAN paging area, tracking area, etc.), (viii) quality of service
and/or (ix) RLF conditions.
[0168] Supervision processes may be instantiated on an as-needed
basis, for example, depending whether data transfer may be allowed
in the state. In an example, a WTRU may instantiate supervision
processes (e.g., to monitor dedicated resources), for example, upon
entering a connected state. A WTRU may instantiate supervision
processes as needed or based on a configuration, for example, in a
light connected state that may be configurable to allow or not
allow data transfers.
[0169] A WTRU (e.g., when data transfers may be permitted) may be
configured to use one or more of the following data transfer
methods/resources: (i) grant-less, (ii) common/shared and/or (iii)
dedicated.
[0170] A WTRU may instantiate different supervision processes for a
(e.g., each) data transfer method. A WTRU may instantiate
additional supervision processes, for example, to enforce other
characteristics that may be specific to each state.
[0171] Supervision processes may not be required or used, for
example, when data transfer may not be allowed.
[0172] A WTRU may transition to a light connected state and resume
a connection, for example, when the WTRU may be in a connected
state and a radio link failure may be detected. A WTRU may, e.g.,
alternatively, transition to idle and initiate a re-establishment
procedure. A WTRU (e.g., in light connected state) may, for
example, attempt to recover within its present state (e.g., using
dedicated resources), attempt to recover using other resources
(e.g., common, grant-less) or (e.g., alternatively) transition to
idle.
[0173] A WTRU may instantiate supervision processes, for example,
based on one or more (e.g., specific) control channels associated
with a state. In an example, a WTRU may determine the type of
channels to monitor, for example, based on the data transfer
methods/resources associated with the state. In an (e.g., another)
example, a WTRU may instantiate a (e.g., similar) supervision
process to monitor the paging channel in light connected and
connected states. A WTRU (e.g., in light connected state) may
operate with a longer DRX and may monitor a paging channel for
system information update (e.g., while monitoring for an incoming
call). A WTRU (e.g., in connected state) may monitor a paging
channel (e.g., only) for system information update (e.g., related
to ETWS and CMAS) using a different DRX.
[0174] In an example, a WTRU (e.g., in idle state) may instantiate
supervision processes to monitor a broadcast channel and a paging
channel. Monitoring a broadcast channel and a paging channel may be
beneficial (e.g., for URLLC), for example, when a WTRU detects poor
reliability on a broadcast and/or a paging channel. A WTRU may
initiate transition to either light connected or connected state
(e.g., to meet latency and reliability requirements). The WTRU may
continue to monitor channel conditions. A WTRU may transition back
to idle state, for example, when broadcast/paging channel
condition(s) return to normal. This operation may provide a
proactive mechanism to enable a WTRU to meet low latency
requirements.
[0175] A supervision process may be instantiated to monitor and
ensure proper cell measurements for the type of mobility supported
in a (e.g., each) state. For example, a WTRU may perform neighbor
cell measurements differently based on the state. A WTRU (e.g., in
light connected state) may perform cell reselection, for example,
when a data transfer may be not allowed or may be allowed but not
ongoing. A WTRU (e.g., in connected state) may perform measurement
reports to assist network controlled handover. A WTRU (e.g., when
data transfer may be allowed in light connected state) may (e.g.,
also) perform measurement reports to support network controlled
handover. Criteria that may be used to evaluate neighbor cells may
be different in each state. For example, a WTRU may use less
stringent values in light connected state compared to the connected
state. In an example, a WTRU may stay camped/connected to a current
cell longer rather than reselecting or performing a handover to a
higher performing cell. A WTRU may prioritize cells belonging to
the same RAN paging area over cells belonging to another RAN paging
area or tracking area. A list of neighbor cells to measure may be
based on the state. In an example, a neighbor list in light
connected state may be a subset of a neighbor list in a connected
state. In an example, a WTRU (e.g., in light connected state) may
move out of a RAN PA while a data transfer may be ongoing and while
a supervision process may be running. The WTRU may perform a RAN
paging area update and network controlled handover may be
triggered, for example, when session continuity may be supported.
Data transfer may be dropped, for example, when session continuity
may be not required. A WTRU may perform a RAN paging area update
and may re-initiate the connection in the new RAN paging area. A
WTRU may (e.g., alternatively) transition to a connected state upon
detection of a RAN paging area update.
[0176] Supervision may be based on WTRU transmission(s).
Supervision procedures that may be based on reference signal
transmissions from a transmission point or a cell may: (i) increase
overhead (e.g., in an ultra-dense deployment where TRP density may
be much higher than WTRU density) an/or (ii) be energy inefficient
(e.g., from a network perspective).
[0177] A supervision procedure based on WTRU transmission may be
defined. A WTRU may provide assistance to a reception based
supervision process at the network. A transmission based
supervision process (e.g., from a WTRU perspective) may be defined
to perform one or more of the following operations: (i)
transmission of a `UL supervision signal` and/or (ii) reception and
processing of a network response corresponding to a UL supervision
signal transmission. A UL supervision signal may be, for example, a
reference signal, a preamble, a training sequence and/or a
demodulation reference signal. An UL supervision signal may be a
standalone transmission or may be attached to a regular data
transmission.
[0178] A WTRU may be configured (e.g., by a network) with resources
for a UL supervision signal transmission. Resources may include
time/frequency resources, WTRU specific sequence, periodicity, etc.
In an example, UL supervision signal resources may be periodic and
may be configured in a broadcast and/or in WTRU specific signaling.
In an example, a network may dynamically request UL supervision
signal transmission (e.g., as a part of a control message or
multiplexed with UL data). In an example, UL resources for a
supervision signal may be reserved across multiple TRPs. A WTRU
transmission may be received by those TRPs.
[0179] A WTRU may instantiate a transmission based supervision
process, for example, based on one or more of the following
criteria: (i) when the reception based supervision process meets a
certain criteria (e.g., DL signal quality drops below a threshold),
(ii) when a DL supervision signal may not be periodically broadcast
by a network, (iii) when explicitly triggered by a network, (iv)
based on WTRU mobility state (e.g., when WTRU speed or number of
reselections/handover may be above a threshold) and/or (v) when a
WTRU may be configured with `UL supervision signal` resources
and/or when those resources may be activated.
[0180] A WTRU may receive a response for a UL supervision signal,
for example, for every N transmissions of the supervision signal,
where N may be greater than or equal to 1. A network may respond,
for example, with a predefined DL signal, an acknowledgement in a
control channel and/or in a RAN paging message with a logical value
that may be indicative of a quality of a WTRU supervision signal. A
WTRU may declare a supervision failure, for example, when no
response may be received from the network for a predefined time
interval.
[0181] A supervision process may be associated with a control
function, a MAC instance, a layer or a radio interface. A radio
link monitoring procedure in a WTRU may assume failure in layer 3
connectivity for different failure scenarios across multiple (e.g.,
all) protocol layers, such as an L1 failure (e.g., due to
Out-of-Sync), a MAC failure (e.g., due to random access failure)
and an RLC failure (e.g., when a max retransmission may be
reached). A layer 3 procedure (e.g., cell selection and RRC
Reestablishment) may (e.g., as a consequence) recover the link in
multiple failure scenarios.
[0182] A supervision and recovery process may be associated with,
for example, one or more of the following aspects: (i) a control
function, (ii) a MAC instance and/or (iii) a layer or radio
interface.
[0183] A supervision and recovery process may be associated with a
control function. A WTRU may instantiate a supervision process
associated with a control function. In an example, a WTRU (e.g., in
a distributed architecture) may have separate supervision processes
for one or more edge control functions and a central control
function. A WTRU may differentiate between a failure of an edge
control function and a failure of a central control function. A
supervision process may store a relation between a control message
(e.g., a configuration) and the origin of a control message (e.g.,
an edge control function). A WTRU (e.g., upon receiving an invalid
configuration or a security failure) may trigger recovery methods
associated with a control function. A WTRU may detect and recover
an edge control failure without involving a central control
function.
[0184] A supervision and recovery process may be associated with a
MAC instance. A WTRU may instantiate a supervision process
associated with a MAC instance. For example, a WTRU (e.g., in a
multi-connectivity scenario) may have a plurality of supervision
processes (e.g., one per MAC instance). A WTRU may instantiate a
supervision process, for example, when an associated MAC instance
may be activated or when a WTRU starts to monitor a control channel
associated with a MAC instance. A WTRU may obtain a configuration
for a supervision process, for example, from a dedicated control
message associated with a MAC instance, from system information
associated with a transmission point, from an anchor MAC instance
or from a (pre)configuration in an access table. A recovery
procedure may be a function of a MAC instance and the type of
service associated with the MAC instance. A WTRU may perform
autonomous mobility between a set of MAC instances. A WTRU may
perform supervision (e.g., only) for MAC instances from which a
WTRU may receive scheduling grants.
[0185] A supervision and recovery process may be associated with a
layer or radio interface. A WTRU may instantiate a supervision
process associated with a layer or radio interface. In an example,
a WTRU may be connected to LTE+NR layers (e.g., with a tight
coordination between them). NR and/or LTE layers may be a macro
layer or a small cell layer. A WTRU may instantiate multiple (e.g.,
two) supervision processes, e.g., one associated with the LTE layer
and another associated with the NR layer. An LTE layer may not
understand the configuration for NR supervision, the type of
failures to be detected and/or procedures to recover from an NR
failure for one or more services that may be specific to the NR
layer (e.g., a URLLC service). A supervision process associated
with the NR layer may detect and recover failures in an NR layer
with no or minimal interaction with the LTE layer.
[0186] A (e.g., each) supervision process may be associated with a
recovery method. A recovery method may be (e.g., explicitly)
configured as a part of a supervision process. A WTRU may (e.g.,
upon a supervision failure) trigger a recovery method associated
with a supervision process. An expected recovery performance may be
configured (e.g., in terms of interruption time and/or overhead). A
WTRU may choose/determine a recovery procedure that may meet
performance requirements. A WTRU may determine available recovery
procedures, for example, based on the presence/characteristics of
configured recovery resources.
[0187] A plurality of recovery procedures may be defined. A (e.g.,
each) recovery procedure may provide a tradeoff between different
levels of overhead and service interruption. A WTRU may select a
recovery procedure, for example, based on one or more of the
following: (i) a service affected by the interruption (e.g., URLLC
or eMBB), (ii) failure criteria or event (e.g., control channel
failure, data transmission failure or QoS failure) and/or (iii)
failure of a previous recovery method (e.g., when a dedicated
random access fails, switch to a different cell or perform
alternate recovery).
[0188] In an example, a WTRU (e.g., with multiple active services)
may (e.g., upon a supervision failure) trigger a recovery procedure
associated with a service that may have the least tolerance to an
interruption. In an (e.g., another) example, a WTRU may be (e.g.,
explicitly) configured with a recovery procedure to use upon a
supervision failure.
[0189] A WTRU may ensure that a transmission point or cell selected
after recovery may support one or more (e.g., all) services or
features that are supported or were active at the time of
failure.
[0190] A recovery procedure such as cell selection and
re-establishment may lead to (e.g., significant) service
interruption time, such as for services that may not tolerate
delays (e.g., URLLC). A recovery procedure may be optimized (e.g.,
steps may be avoided or added) to reduce the interruption
times.
[0191] In an example of recovery optimization, a WTRU may retain
parts of a context and reuse them upon recovery (e.g., instead of
releasing configured resources).
[0192] In an example of recovery optimization, a WTRU may stay in
connected mode or move to a light connected state (e.g., instead of
transition to idle mode).
[0193] In an example of recovery optimization, a WTRU may utilize
past measurement results and/or utilize one or more other
procedures (e.g., described below) to pre-establish a link to a
neighbor TRP before the serving TRP supervision failure (e.g.,
instead of executing a cell selection).
[0194] In an example of recovery optimization, a WTRU may utilize
alternate access procedures (e.g., use a grant-less access), for
example, instead of a contention based random access.
[0195] In an example of recovery optimization, a WTRU may utilize
preconfigured resources that may reduce contention (e.g., a group
resource) or avoid contention (e.g., a dedicated resource), for
example, instead of waiting for contention resolution.
[0196] In an example of recovery optimization, a WTRU may perform
faster layer1 or layer2 based recovery (e.g., instead of performing
a layer 3 procedure such as a re-establishment procedure).
[0197] A WTRU may perform a recovery procedure, for example, using
pre-defined/configured radio resources, which may be referred to as
"recovery resources." One or more aspects of recovery resources may
be dedicated for a recovery procedure and/or dedicated for a
specific WTRU or group of WTRUs. Examples of recovery resources may
include one or more of the following: (i) a random access preamble
or a preamble group, (ii) recovery resource periodicity (e.g., one
or more symbols or subframe), (iii) recovery resource sub-band
(e.g., group of subcarriers such as resource blocks), (iv) a
grant-less resource (e.g., orthogonal or non-orthogonal resource,
synchronous or asynchronous resource), (v) an uplink control
channel resource, and/or (vi) an uplink signal resource (e.g., a
supervision signal resource or sounding reference signal
resource).
[0198] A WTRU may be configured with recovery resources that may be
applicable across two or more cells/transmission points. For
example, a WTRU may be configured with recovery resources that may
be valid for a RAN paging area. A WTRU may receive (e.g., in
dedicated signaling) a configuration of recovery resources. In an
(e.g., alternative) example, recovery resources may be common for a
group of WTRUs. A WTRU may obtain the configuration of recovery
resources in broadcast signaling. A WTRU may trigger an on-demand
system information acquisition procedure to obtain a recovery
resource configuration. A WTRU may determine that recovery
resources may be valid based on one or more criteria.
[0199] Recovery resources may be determined to be valid, for
example, based on receiving a valid recovery resource configuration
(e.g., dedicated or broadcast).
[0200] Recovery resources may be determined to be valid, for
example, based on explicit activation from the network (e.g., in
MAC or L1 signaling). For example, a network may activate recovery
resources based on WTRU feedback and/or a measurement report.
[0201] Recovery resources may be determined to be valid, for
example, based on a state of a supervision process, such as when a
supervision process meets a failure criteria (e.g., hypothetical
control channel quality below a threshold).
[0202] Recovery resources may be determined to be valid, for
example, based on configured services. For example, a WTRU may use
recovery resources for services that may expect lower interruption
times (e.g., an ultra-low latency service/flow).
[0203] A WTRU specific recovery resource may reduce the
interruption time (e.g., potentially at a slight increase in
resource cost). Service interruption may be minimized at a WTRU,
for example, when (i) a need to perform contention resolution may
be avoided, (ii) an explicit WTRU identification may not be
required, such as when invocation/usage of a dedicated recovery
resource provides an implicit identity of a WTRU and/or (iii) a
recovery procedure may not require a layer 3 signaling exchange and
may eliminate additional delay due to layer 3 processing.
[0204] Recovery resources may be shared by a subset of WTRUs in a
cell, which may provide a better tradeoff between
contention/collision and resource utilization.
[0205] A WTRU may (e.g., explicitly) request recovery resources for
a first cell or transmission point using a second cell or
transmission point. For example, a WTRU may be connected to two or
more transmission points (e.g., in NR). A WTRU may request recovery
resources for a transmission point, for example, when an associated
supervision process meets a failure criteria.
[0206] A WTRU may request recovery resources on a first layer for a
second layer. For example, a WTRU may request NR recovery resources
on a LTE carrier. A request may be based on, for example, a failure
of a supervision process on an NR layer.
[0207] User plane recovery may be provided. A supervision process
and recovery mechanism associated with user plane functions may be
different from control plane functions. In an example, user plane
functions and control plane functions for a WTRU may terminate at
different MAC instance/cell/TRP. A WTRU may perform user plane
recovery decoupled/independent from control plane recovery.
[0208] A recovery procedure performed by a WTRU may be a function
of on QoS/packet forwarding treatment. The granularity of recovery
may be at a packet forwarding treatment or abstraction thereof
(e.g., flow/bearer). A WTRU may not trigger recovery for all active
services/flows at the same time. For example, certain
services/flow/packet forwarding treatments (e.g., URLLC) may be
sensitive to interruption. A more conservative supervision process
may, for example, trigger recovery faster than for an mMTC
service.
[0209] A WTRU may (e.g., in the event of a supervision failure)
retain parts of layer 2 context (e.g., parts of a layer 2
configuration and/or protocol state of layer 2). A WTRU may
activate layer 2 configuration associated with a light connected
state. A WTRU may perform data transfer (e.g., when allowed) in
light connected state while recovery for a fully connected state
may be ongoing.
[0210] A WTRU may (e.g., alternatively or additionally) transition
to a sub-state of a connected state, for example, where
connectionless data transfer may be supported. A WTRU may (e.g.,
upon a supervision failure) stop using resources configured for a
connected state. A WTRU may fall back to connectionless transfer
for user plane data (e.g., during control plane recovery) and may
transition to connection based transfer (e.g., when the control
plane recovery may be complete).
[0211] A WTRU may be connected to a plurality of MAC
instances/cells/TRPs. A WTRU may be actively scheduled by a subset
of the MAC instances (e.g., one or more serving/active MAC
instances). A WTRU may replicate data transmission to other MAC
instances (one or more supporting MAC instances), for example, when
a supervision process for a user plane function associated with a
MAC instance meets a failure criteria (e.g., a failed MAC
instance). A WTRU may select one or more companion MAC instances
based on, for example, signal quality, availability of valid UL
timing, status of supervision process, etc. Data replication for
supporting MAC instances may be autonomously performed by a WTRU. A
WTRU may indicate a start of data replication using a control
message (e.g., a buffer status request) to the supporting MAC
instances. A buffer status request may (e.g., additionally)
indicate, for example, a type of service/expected quality of
service, identity of failed MAC instance, etc. A WTRU may stop data
replication, for example, when a radio link of the failed MAC
instance improves. Similar mechanisms may be also applied for
downlink data transmissions. For example, WTRU based on supervision
thresholds may trigger supporting MAC instances to transmit
downlink transfer (e.g., in addition to the serving MAC instances).
A WTRU may trigger a supporting MAC instance, for example, using a
layer1/2 or higher layer message. TRP diversity in downlink
transmission may increase reliability of the data transfer. A WTRU
(e.g., to avoid excess resource usage due to data replication) may
be configured with a maximum duration for which data replication
may be allowed. A WTRU (e.g., upon exceeding a maximum duration)
may consider a failed MAC instance as disconnected and may promote
a supporting MAC instance to a serving MAC instance (e.g., when not
already serving).
[0212] Control plane recovery may be provided. A WTRU (e.g., upon a
supervision failure) may retain/store a context (or portion
thereof) associated with a serving transmission point(s). A context
may include, for example, a received configuration (e.g., a radio
resource configuration), security context and protocol state (e.g.,
state/buffers of a reordering protocol, an ARQ protocol and/or a
HARQ protocol). A WTRU may retain parts of an overall WTRU context.
A WTRU may determine the parts of context to reset, for example, as
a function of a supervision process, the type of failure and/or the
type of service.
[0213] A recovery procedure may be a function of WTRU state. A WTRU
may transition to a light connected state, for example, upon
experiencing radio link failure in a connected state. A WTRU may
utilize one or more reconnection procedures that may be defined in
light connected state as a recovery procedure/method. A WTRU may
monitor a RAN paging message, for example, while performing
recovery in a light connected state. A WTRU may receive a
configuration for dedicated recovery resources in a RAN paging
message. A WTRU may be preconfigured with a light connectivity
configuration while in connected state. A WTRU may apply/retain a
subset of connected state configuration while in light connected
state. A configuration may be valid, for example, in an entire RAN
paging area. In an example, a WTRU may experience a supervision
failure in light connected state (e.g., based on reliability of RAN
paging channel). A WTRU may transition from a light connected state
to an idle state and may perform a tracking area update procedure
or a NAS signaling procedure, for example, to synchronize the WTRU
state and core network state. A tracking area update or NAS
signaling procedure may be implemented, for example, when a WTRU
and core network may not be synchronized in a light connected
state. For example, a WTRU may be in a light connected state from a
RAN point of view while the WTRU may be in a connected state from a
core network point of view.
[0214] A WTRU may autonomously establish a link to neighbor TRPs
before a supervision failure, e.g., while a serving TRP may be
close to a supervision failure or operating in sub-optimal radio
conditions. A WTRU may read broadcast information from a neighbor
TRP to perform initial access. A WTRU may (e.g., alternately)
request (e.g., from the serving TRP) system information for a
neighbor cell. For example, a serving TRP may (e.g., alternatively)
provide system information for a neighbor TRP, for example, based
on a measurement report from a WTRU. WTRU triggered autonomous
multi-connectivity or a make-before-break connection may be made to
a different TRP, for example, based on triggering, e.g., by early
stage RLF detection.
[0215] A WTRU may receive and store a radio resource configuration
that may be associated with one or more neighbor cells. A radio
resource configuration may be dedicated to a WTRU and/or specific
to active services in a WTRU. A radio resource configuration may be
specific to a supervision process. A WTRU may receive and may store
a configuration of an activation signal that may be linked to a
(e.g., each) neighbor cell radio resource configuration. In an
example, an activation signal may include a UL resource for a
signal/preamble control transmission from a WTRU. A WTRU (e.g.,
upon a supervision process failure) may select a neighbor cell and
may trigger a UL activation signal associated with the neighbor
cell. A network may confirm reception of the activation signal. A
WTRU (e.g., upon confirmation) may apply the stored configuration
associated with the neighbor cell. A pre-configuration and fast UL
signal based activation may eliminate delays due to, for example,
random access and layer signaling, and may (e.g., significantly)
reduce recovery time.
[0216] A WTRU (e.g., upon successful recover) may indicate (e.g.,
to a network) a reason for failure. An indication may include a
supervision process identity. Multiple parallel supervision
processes may be active at a WTRU. Each of multiple processes may
correspond to a different QoS. A WTRU may report the status of a
supervision process associated with a URLLC service, for example,
by including a failure reason with a supervision process ID, e.g.,
while other services such as eMBB may still be active.
[0217] A WTRU may experience a failure of a supervision process
associated with a low latency control channel. A WTRU may (e.g., as
a recovery procedure) switch to a regular control channel, a
control channel with a longer TTI/periodicity, a control channel
with better protection (e.g., coding), an enhanced coverage control
channel (e.g., with repetition) or a control channel on a low
frequency carrier.
[0218] A recovery procedure may be specific to a supervision
process associated with a beam process. A WTRU (e.g., upon a
supervision process failure) may use other active beam processes to
indicate to a network a reason for failure and may trigger a
recovery procedure. For example, a WTRU may trigger beam refinement
or a beam training procedure as a recovery procedure upon a
supervision failure.
[0219] FIGS. 2-4 provide examples of supervisory processes. FIGS.
2-4 show a node or TRP communicating with a WTRU. Each TRP has
beams y and z. FIG. 3 shows a radio link failure has been
determined, and FIG. 4 shows an example recovery.
[0220] FIGS. 2-4 can use any of the supervisory processes described
herein. For example, the WTRU may monitors the RSx associated with
TTI duration x. The failure criteria or event may be defined as if
RSx<a threshold-x for time Tx. The WTRU monitors the RSx and
determines if the failure event threshold is satisfied. If the WTRU
determines that the failure criteria is met, the WTRU determines to
and performs a recovery action. In this example, the recover action
can be to fallback to TTI duration y.
[0221] In another example, the WTRU may monitor the RSy associated
with beam y. The failure criteria or event may be defined as if
RSy<a threshold-y for time Ty. The WTRU monitors the RSy and
determines if the failure event threshold is satisfied. If the WTRU
determines that the failure criteria is satisfied, the WTRU
determines to and performs a recovery action. In this example, the
recover action may include triggering beam training on recovery
resource z, as shown in FIG. 4.
[0222] In another example, the WTRU may monitor the RSz associated
with beam z. The failure criteria or event may be defined as if
RSz<a threshold-z for time Tz. The WTRU monitors the RSz and
determines if the failure event threshold is satisfied. If the WTRU
determines that the failure criteria is satisfied, the WTRU
determines to and performs a recovery action. In this example, the
recovery action may include triggering beam training on recovery
resource y.
[0223] In another example, the WTRU may monitor the average data
packet latency for URLLC. The failure criteria or event may be
defined as if the average data packet latency<a threshold time.
The WTRU monitors the average data packet latency and determines if
the failure event threshold is satisfied. If the WTRU determines
that the failure criteria is satisfied, the WTRU determines to and
performs a recovery action. In this example, the recovery action
may include triggering a different transmission method.
[0224] Systems, methods, and instrumentalities are disclosed for
connectivity supervision and recovery. A WTRU may supervise its
capability to transmit and receive data, including in the absence
of a control channel (e.g., grant-less transmission). A supervision
framework may permit a WTRU to supervise, for example, quality of a
feedback channel, quality of reciprocal resources and/or
transmission attempts. A supervision process may be a function of a
control channel structure or WTRU state. A supervision process may
be associated with a quality of service. A supervision process may
be based on WTRU transmission for energy/resource efficient
operation. Multiple Recovery procedures may be defined. A recovery
procedure may be a function of a supervision process. A recovery
procedure may be optimized for low latency services. Recovery
procedures may involve dedicated resources for recovery, transition
to light connection, grant-less resource, etc. User plane recovery
may include reuse of layer2 context, data replication to companion
MAC instances, etc. Control plane recovery may use RAN paging, WTRU
triggered multi-connectivity, etc. A recovery procedure for a
supervision process associated with a beam process may include WTRU
triggering beam training/beam refinement, etc.
[0225] Processes and instrumentalities described herein may apply
in any combination and may apply to other wireless technologies and
other services.
[0226] A WTRU may refer to an identity of the physical device, or
to the user's identity such as subscription related identities,
e.g., MSISDN, SIP URI, etc. WTRU may refer to application-based
identities, e.g., user names that may be used per application.
[0227] Each of the computing systems described herein may have one
or more computer processors having memory that are configured with
executable instructions or hardware for accomplishing the functions
described herein including determining the parameters described
herein and sending and receiving messages between entities (e.g.,
WTRU and network) to accomplish the described functions. The
processes described above may be implemented in a computer program,
software, and/or firmware incorporated in a computer-readable
medium for execution by a computer and/or processor.
[0228] The processes described above may be implemented in a
computer program, software, and/or firmware incorporated in a
computer-readable medium for execution by a computer and/or
processor. Examples of computer-readable media include, but are not
limited to, electronic signals (transmitted over wired and/or
wireless connections) and/or 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, but not limited to, internal hard disks and
removable disks, magneto-optical media, and/or optical media such
as CD-ROM disks, and/or digital versatile disks (DVDs). A processor
in association with software may be used to implement a radio
frequency transceiver for use in a WTRU, terminal, base station,
RNC, and/or any host computer.
* * * * *