U.S. patent application number 17/741372 was filed with the patent office on 2022-09-01 for modified backhaul random access channel.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Navid Abedini, Muhammad Nazmul Islam, Jianghong Luo, Tao Luo.
Application Number | 20220279600 17/741372 |
Document ID | / |
Family ID | |
Filed Date | 2022-09-01 |
United States Patent
Application |
20220279600 |
Kind Code |
A1 |
Islam; Muhammad Nazmul ; et
al. |
September 1, 2022 |
MODIFIED BACKHAUL RANDOM ACCESS CHANNEL
Abstract
Methods, systems, and devices for wireless communications are
described that support different, or adjusted, random access
channel (RACH) preamble formats for efficient use of shared RACH
time-frequency resources. The described techniques provide for
assigning different RACH preamble formats to wireless devices that
have a higher link budget, whereupon the devices may transmit the
different RACH preamble using the link budget available to them in
one or more RACH transmission opportunities in the shared RACH
time-frequency resources. Such methods, systems, and devices may
allow for more RACH transmission opportunities, as well as less
interference between RACH transmissions. For example, wireless
devices communicating over a backhaul network may have a higher
link budget than wireless devices communicating over an access
network. As such, RACH preambles transmitted by the wireless
devices communicating over the backhaul network may be shorter than
RACH preambles transmitted by the wireless devices communicating
over the access network.
Inventors: |
Islam; Muhammad Nazmul;
(Littleton, MA) ; Abedini; Navid; (Basking Ridge,
NJ) ; Luo; Tao; (San Diego, CA) ; Luo;
Jianghong; (Skillman, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Appl. No.: |
17/741372 |
Filed: |
May 10, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16663030 |
Oct 24, 2019 |
11330639 |
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17741372 |
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62754381 |
Nov 1, 2018 |
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International
Class: |
H04W 74/08 20060101
H04W074/08; H04L 5/00 20060101 H04L005/00; H04W 74/00 20060101
H04W074/00; H04W 52/14 20060101 H04W052/14; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method for wireless communication by a first access node,
comprising: receiving, from a second access node, configuration
signaling indicating a shared random access channel resource and a
backhaul random access channel preamble format, the backhaul random
access channel preamble format differing from an access random
access channel preamble format; transmitting, to the second access
node, a backhaul random access message in accordance with the
backhaul random access channel preamble format within the shared
random access channel resource; and establishing a backhaul link
with the second access node based at least in part on the backhaul
random access message.
Description
CROSS REFERENCE
[0001] The present Application for Patent is a Continuation of U.S.
patent application Ser. No. 16/663,030 by ISLAM et al, entitled
"MODIFIED BACKHAUL RANDOM ACCESS CHANNEL" filed Oct. 24, 2019,
which claims the benefit of U.S. Provisional Patent Application No.
62/754,381 by ISLAM et al., entitled "MODIFIED BACKHAUL RANDOM
ACCESS CHANNEL," filed Nov. 1, 2018, assigned to the assignee
hereof, and expressly incorporated herein.
INTRODUCTION
[0002] The following relates generally to wireless communications,
and more specifically to managing a random access channel
(RACH).
[0003] Wireless communications systems are widely deployed to
provide various types of communication content such as voice,
video, packet data, messaging, broadcast, and so on. These systems
may be capable of supporting communication with multiple users by
sharing the available system resources (e.g., time, frequency, and
power). Examples of such multiple-access systems include fourth
generation (4G) systems such as Long Term Evolution (LTE) systems,
LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth
generation (5G) systems which may be referred to as New Radio (NR)
systems. These systems may employ technologies such as code
division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal
frequency division multiple access (OFDMA), or discrete Fourier
transform spread orthogonal frequency division multiplexing
(DFT-S-OFDM). A wireless multiple-access communications system may
include a number of base stations or network access nodes, each
simultaneously supporting communication for multiple communication
devices, which may be otherwise known as user equipment (UE).
SUMMARY
[0004] A method of wireless communication by a first access node is
described. The method may include receiving, from a second access
node, configuration signaling indicating a shared RACH resource and
a backhaul RACH preamble format, the backhaul RACH preamble format
differing from an access RACH preamble format. The first access
node may transmit, to the second access node, a backhaul random
access message in accordance with the backhaul RACH preamble format
within the shared RACH resource, and may establish a backhaul link
with the second access node based on the backhaul random access
message.
[0005] An apparatus for wireless communication by a first access
node is described. The apparatus may include a processor and memory
coupled with the processor. The processor and memory may be
configured to receive, from a second access node, configuration
signaling indicating a shared RACH resource and a backhaul RACH
preamble format, the backhaul RACH preamble format differing from
an access RACH preamble format. The processor and memory may be
further configured to transmit, to the second access node, a
backhaul random access message in accordance with the backhaul RACH
preamble format within the shared RACH resource and establish a
backhaul link with the second access node based on the backhaul
random access message.
[0006] Another apparatus for wireless communication by a first
access node is described. The apparatus may include means for
receiving, from a second access node, configuration signaling
indicating a shared RACH resource and a backhaul RACH preamble
format, the backhaul RACH preamble format differing from an access
RACH preamble format. The apparatus may further include means for
transmitting, to the second access node, a backhaul random access
message in accordance with the backhaul RACH preamble format within
the shared RACH resource, and establishing a backhaul link with the
second access node based on the backhaul random access message.
[0007] A non-transitory computer-readable medium storing code for
wireless communication by a first access node is described. The
code may include instructions executable by a processor to receive,
from a second access node, configuration signaling indicating a
shared RACH resource and a backhaul RACH preamble format, the
backhaul RACH preamble format differing from an access RACH
preamble format. The code may further include instructions
executable by a processor to transmit, to the first access node, a
backhaul random access message in accordance with the backhaul RACH
preamble format within the shared RACH resource, and establish a
backhaul link with the first access node based on the backhaul
random access message.
[0008] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the configuration signaling further may include operations,
features, means, or instructions for receiving the configuration
signaling indicating a set of different backhaul RACH occasions
within the shared RACH resource.
[0009] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for selecting a first
backhaul RACH occasion from the set of different backhaul RACH
occasions, where the backhaul random access message may be
transmitted within the first backhaul RACH occasion.
[0010] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, selecting
the first backhaul RACH occasion further may include operations,
features, means, or instructions for identifying a number of
downstream access nodes and selecting the first backhaul RACH
occasion from the set of different backhaul RACH occasions based on
the number of downstream access nodes.
[0011] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the configuration signaling further may include operations,
features, means, or instructions for receiving the configuration
signaling indicating a prohibited backhaul RACH occasion of the set
of different backhaul RACH occasions.
[0012] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the
shared RACH resource may be a time and frequency resource useable
for both access and backhaul communications.
[0013] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the configuration signaling further may include operations,
features, means, or instructions for receiving the configuration
signaling indicating a number of symbols in the backhaul RACH
preamble format, the number of symbols being fewer than a number of
symbols in the access RACH preamble format.
[0014] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the configuration signaling further may include operations,
features, means, or instructions for receiving the configuration
signaling indicating a number of symbols in the backhaul RACH
preamble format, the number of symbols being the same as a number
of symbols in the access RACH preamble format.
[0015] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the backhaul random access message further may include
operations, features, means, or instructions for selecting a
transmission power for the backhaul random access message based on
a first parameter for received power. In some examples, the first
parameter for received power may exceed a second parameter for
received power for an access random access message configured for
transmission by a UE. In some examples of the method, apparatuses,
and non-transitory computer-readable medium described herein,
transmitting the backhaul random access message further may include
operations, features, means, or instructions for transmitting the
backhaul random access message in accordance with the selected
transmission power.
[0016] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the backhaul random access message further may include
operations, features, means, or instructions for transmitting, via
a set of antennas, the backhaul random access message as a
beamformed transmission.
[0017] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the first
access node may be a mobile termination (MT) unit of an integrated
access/backhaul (IAB).
[0018] A method of wireless communication by a first access node is
described. The method may include transmitting, to a second access
node, first configuration signaling indicating a shared RACH
resource and a backhaul RACH preamble format. The method may
additionally include transmitting, to a UE, second configuration
signaling indicating the shared RACH resource and an access RACH
preamble format, the backhaul RACH preamble format differing from
the access RACH preamble format. Similarly, the method may include
monitoring the shared RACH resource for at least one of a first
random access message in accordance with the backhaul RACH preamble
format or a second random access message in accordance with the
access RACH preamble format.
[0019] An apparatus for wireless communication by a first access
node is described. The apparatus may include a processor and memory
coupled with the processor. The processor and memory may be
configured to transmit, to a second access node, first
configuration signaling indicating a shared RACH resource and a
backhaul RACH preamble format. The processor and memory may be
further configured to transmit, to a UE, second configuration
signaling indicating the shared RACH resource and an access RACH
preamble format, the backhaul RACH preamble format differing from
the access RACH preamble format. Additionally, the processor and
memory may be configured to monitor the shared RACH resource for at
least one of a first random access message in accordance with the
backhaul RACH preamble format or a second random access message in
accordance with the access RACH preamble format.
[0020] Another apparatus for wireless communication by a first
access node is described. The apparatus may include means for
transmitting, to a second access node, first configuration
signaling indicating a shared RACH resource and a backhaul RACH
preamble format. Additionally, the apparatus may include means for
transmitting, to a UE, second configuration signaling indicating
the shared RACH resource and an access RACH preamble format, the
backhaul RACH preamble format differing from the access RACH
preamble format. The apparatus may further include means for
monitoring the shared RACH resource for at least one of a first
random access message in accordance with the backhaul RACH preamble
format or a second random access message in accordance with the
access RACH preamble format.
[0021] A non-transitory computer-readable medium storing code for
wireless communication by a first access node is described. The
code may include instructions executable by a processor to
transmit, to a second access node, first configuration signaling
indicating a shared RACH resource and a backhaul RACH preamble
format. The code may further include instructions executable by a
processor to transmit, to a UE, second configuration signaling
indicating the shared RACH resource and an access RACH preamble
format, the backhaul RACH preamble format differing from the access
RACH preamble format. The code may also include instructions
executable by a processor to monitor the shared RACH resource for
at least one of a first random access message in accordance with
the backhaul RACH preamble format or a second random access message
in accordance with the access RACH preamble format.
[0022] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
monitoring the shared RACH resource further may include operations,
features, means, or instructions for receiving, from the second
access node, the first random access message in accordance with the
backhaul RACH preamble format within the shared RACH resource, and
establishing a backhaul link with the second access node based on
the first random access message.
[0023] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
monitoring the shared RACH resource further may include operations,
features, means, or instructions for receiving, from the UE, the
second random access message in accordance with the access RACH
preamble format within the shared RACH resource, and establishing
an access link with the UE based on the second random access
message.
[0024] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the second random access message in accordance with the access RACH
preamble format further may include operations, features, means, or
instructions for detecting, using an energy detection algorithm, a
signal that includes the first random access message in accordance
with the backhaul RACH preamble format within the shared RACH
resource. In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, receiving
the second random access message in accordance with the access RACH
preamble format further may include operations, features, means, or
instructions for generating a modified signal by removing the first
random access message from the signal, and processing the modified
signal to obtain the second random access message.
[0025] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the first configuration signaling further may include
operations, features, means, or instructions for transmitting the
first configuration signaling indicating a number of symbols in the
backhaul RACH preamble format, the number of symbols being fewer
than a number of symbols in the access RACH preamble format.
[0026] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the first configuration signaling further may include
operations, features, means, or instructions for transmitting the
first configuration signaling indicating a number of symbols in the
backhaul RACH preamble format, the number of symbols being the same
as a number of symbols in the access RACH preamble format.
[0027] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the first configuration signaling further may include
operations, features, means, or instructions for transmitting the
first configuration signaling indicating a first parameter for
received power for the first random access message, the first
parameter for received power exceeding a second parameter for
received power for the second random access message configured for
transmission by the UE.
[0028] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the first configuration signaling further may include
operations, features, means, or instructions for transmitting the
first configuration signaling indicating a set of different
backhaul RACH occasions within the shared RACH resource.
[0029] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
monitoring the shared RACH resource further may include operations,
features, means, or instructions for receiving, from the first
access node, the first random access message in accordance with the
backhaul RACH preamble format within a first backhaul RACH occasion
of the set of different backhaul RACH occasions, and identifying
information based on the first backhaul RACH occasion.
[0030] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
identifying the information further may include operations,
features, means, or instructions for identifying a number of
downstream access nodes based on the first backhaul RACH
occasion.
[0031] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
transmitting the first configuration signaling further may include
operations, features, means, or instructions for transmitting the
first configuration signaling indicating a prohibited backhaul RACH
occasion of the set of different backhaul RACH occasions.
[0032] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the
shared RACH resource may be a time and frequency resource useable
for both access and backhaul communications.
[0033] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the first
access node may be a mobile parent of an IAB.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 illustrates an example of a wireless communications
system that supports a modified backhaul RACH in accordance with
one or more aspects of the present disclosure.
[0035] FIGS. 2A, 2B, and 2C illustrate examples of IAB networks
that support a modified backhaul RACH in accordance with one or
more aspects of the present disclosure.
[0036] FIG. 3 illustrates an example of a resource partitioning
scheme that supports a modified backhaul RACH in accordance with
one or more aspects of the present disclosure.
[0037] FIG. 4 illustrates an example of a wireless communications
system that supports a modified backhaul RACH in accordance with
one or more aspects of the present disclosure.
[0038] FIG. 5 illustrates an example of an energy detection
algorithm that supports a modified backhaul RACH in accordance with
one or more aspects of the present disclosure.
[0039] FIG. 6 illustrates an example of a process flow that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure.
[0040] FIGS. 7 and 8 show block diagrams of devices that support a
modified backhaul RACH in accordance with one or more aspects of
the present disclosure.
[0041] FIG. 9 shows a block diagram of a communications manager
that supports a modified backhaul RACH in accordance with one or
more aspects of the present disclosure.
[0042] FIG. 10 shows a diagram of a system including a device that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure.
[0043] FIGS. 11 through 16 show flowcharts illustrating methods
that support a modified backhaul RACH in accordance with one or
more aspects of the present disclosure.
DETAILED DESCRIPTION
[0044] The techniques described herein may support different, or
adjusted, RACH preamble formats for efficient use of shared RACH
time-frequency resources. Generally, the described techniques may
provide for assigning different RACH preamble formats to wireless
devices that have a higher link budget. A wireless device with the
higher link budget may transmit a RACH preamble in the assigned
format in one or more RACH transmission opportunities using the
link budget that is available to the wireless device. For example,
in one aspect, when operating in an IAB network, wireless devices
communicating over a backhaul network portion of the IAB network
may have a higher link budget than wireless devices communicating
over an access network portion of the IAB network. In some
examples, RACH preambles transmitted by the wireless devices
communicating over the backhaul network may correspond to a higher
energy level than RACH preambles transmitted by the wireless
devices communicating over the access network. Additionally or
alternatively, RACH preambles transmitted by the wireless devices
communicating over the backhaul network may be shorter than RACH
preambles transmitted by the wireless devices communicating over
the access network.
[0045] Wireless communications systems may include access nodes to
facilitate wireless communication between one or more UEs and a
network. For example, an LTE or NR base station may provide a
mobile device access to the internet via the wireless network and
may thus function as an access node. Access nodes may have a
high-capacity, wired, backhaul connection (e.g., fiber) to the
network. In some deployments, however, it may be desirable to
deploy a larger number of access nodes in a small area to provide
coverage to users. In such deployments, some networks or portions
thereof may be configured as IAB networks where one or more access
nodes have wireless backhaul connections to the network. Deployment
and operation of such access nodes with wireless backhaul
connections may enable backhaul connections and increase end user
coverage.
[0046] In some wireless communications systems (e.g., a 5G NR
wireless network), wireless devices may support both wireless
access traffic (e.g., between access nodes and UEs) and backhaul
traffic (e.g., traffic between separate access nodes). For example,
the wireless devices may support an IAB network (e.g., a
self-backhauling network), where the network may share time and
frequency resources between access traffic and backhaul traffic.
Accordingly, the IAB network may increase link capacity, reduce
latency, and reduce cell deployment cost within the wireless
communications system. In some cases, the IAB network may be
implemented for millimeter-wave (mmW) systems (e.g., with narrow
beams created using beamforming techniques) to minimize
interference (e.g., inter-link interference) between the different
transmissions. While various examples provided herein describe IAB
networks, the described techniques for backhaul random access
procedures across wireless nodes may be generally applied to any
type of wireless network.
[0047] In order to establish communications between a first
wireless device and a second wireless device (e.g., between a UE
and a base station, between a first access node and a second access
node in an IAB network, etc.), the first wireless device may
transmit a RACH preamble (e.g., as part of a random access
procedure) on a set of shared resources to inform the second device
about the presence of the first wireless device, obtain uplink
synchronization, and request resources for further communications.
Several other messages may follow to complete the random access
procedure, following which the first device may transmit on
resources assigned to it during the random access procedure. An
access node (e.g., base station) in an IAB network may transmit
stronger signals than other wireless devices (e.g., UEs) in the
network since the access node has more transmission power and more
antennas.
[0048] Techniques are described herein to enable the network to
employ the stronger signal provided by access nodes by using
different RACH preamble formats for backhaul traffic and access
traffic. Such techniques may enable more than one backhaul access
node to transmit RACH preambles during one access RACH transmission
duration (e.g., multiple backhaul RACH opportunities may exist
within one access RACH opportunity), may enable one backhaul access
node to transmit multiple RACH messages during one access RACH
transmission, may enable a backhaul access node to transmit a RACH
preamble more efficiently (e.g., faster), or a combination thereof.
Additionally, the techniques may further randomize and reduce
collisions between backhaul and access RACH transmissions.
[0049] For example, prior to initiating a RACH procedure, a first
backhaul access node (e.g., a connecting device) may acquire
information that indicates configuration information for the RACH
procedure from a second backhaul access node (e.g., a serving
device). The second backhaul access node may indicate that the
first backhaul access node may connect to the second backhaul
access node using one of a group of backhaul RACH preamble formats,
which may differ from access RACH preamble formats. In some cases,
the second access node may direct the first access node to use a
specific preamble format based on wireless access network
conditions (e.g., network traffic, measured interference).
Additionally, the second access node may notify the first access
node of multiple backhaul RACH occasions that exist within shared
RACH time-frequency resources (e.g., for both backhaul and access
traffic), where the multiple backhaul RACH occasions occur within
one access RACH occasion corresponding to the access traffic.
[0050] The first access node may select one of the backhaul RACH
occasions and transmit a backhaul RACH preamble using the selected
format. The selected backhaul format and backhaul RACH occasion may
result in a shorter RACH preamble transmission (e.g., backhaul RACH
preamble transmission) when compared with a transmission of an
access RACH preamble. For example, a backhaul access node may
transmit a shorter, higher-energy RACH preamble, based on a higher
transmission power available to the backhaul access node when
compared with access nodes communicating access traffic. The
backhaul and access RACH transmissions may share the same time and
frequency resources, and the shorter backhaul RACH preamble may
take up a portion of the resources used by the access RACH
preamble.
[0051] Such RACH preamble formats may support alignment of
transmissions such that backhaul access nodes may transmit more
than one backhaul RACH preamble, or additional backhaul RACH
messages, in the time it takes to transmit a single access RACH
preamble or additional access RACH message. In some cases, a
shorter backhaul RACH preamble may overlap with an access RACH
preamble in the shared time-frequency resources, which may minimize
the amount of interference between the two types of transmissions.
Therefore, the disclosed method of assigning backhaul RACH preamble
formats may increase system efficiency by both decreasing
interference between backhaul and access RACH transmissions, as
well as supporting a higher number of backhaul RACH
transmissions.
[0052] Aspects of the disclosure are initially described in the
context of exemplary wireless communications systems. Examples of
IAB systems, a resource partitioning scheme, an additional wireless
communications system, an energy detection algorithm, and a process
flow are then described to illustrate aspects of the disclosure.
Aspects of the disclosure are further illustrated by and described
with reference to apparatus diagrams, system diagrams, and
flowcharts that relate to timing adjustment techniques in wireless
communications.
[0053] FIG. 1 illustrates an example of a wireless communications
system 100 that supports a modified backhaul RACH in accordance
with one or more aspects of the present disclosure. The wireless
communications system 100 includes network devices 105 (e.g., base
stations, access nodes), UEs 115, and a core network 130. In some
examples, the wireless communications system 100 may be an LTE
network, an LTE-A network, an LTE-A Pro network, or an NR network.
In some cases, wireless communications system 100 may support
enhanced broadband communications, ultra-reliable (e.g., mission
critical) communications, low latency communications, or
communications with low-cost and low-complexity devices.
[0054] The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The core network 130
may be an evolved packet core (EPC), which may include at least one
mobility management entity (MME), at least one serving gateway
(S-GW), and at least one Packet Data Network (PDN) gateway (P-GW).
The MME may manage non-access stratum (e.g., control plane)
functions such as mobility, authentication, and bearer management
for UEs 115 served by network devices 105 associated with the EPC.
User IP packets may be transferred through the S-GW, which itself
may be connected to the P-GW. The P-GW may provide IP address
allocation as well as other functions. The P-GW may be connected to
the network operators IP services. The operators IP services may
include access to the Internet, Intranet(s), an IP Multimedia
Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.
[0055] At least some of the network devices 105 (e.g., network
device 105-a), which may be an example of a base station (e.g.,
eNB, network access devices, gNB), or network device 105-b, which
may be an example of an access node controller (ANC)), may
interface with the core network 130 through backhaul links 132
(e.g., S1, S2) and may perform radio configuration and scheduling
for communication with the UEs 115. In various examples, the
network devices 105-b may communicate, either directly or
indirectly (e.g., through core network 130), with each other over
backhaul links 134 (e.g., X1, X2), which may be wired or wireless
communication links.
[0056] Each network device 105-b may also additionally or
alternatively communicate with a number of UEs 115 through a number
of other network devices 105-c, where network device 105-c may be
an example of a smart radio head (or through a number of smart
radio heads). In alternative configurations, various functions of
each network device 105 may be distributed across various network
devices 105 (e.g., radio heads and access network controllers) or
consolidated into a single network device 105 (e.g., a base
station).
[0057] Network devices 105 may wirelessly communicate with UEs 115
via one or more base station antennas. Network devices 105
described herein may include or may be referred to by those skilled
in the art as a base transceiver station, a radio base station, an
access point, a radio transceiver, a NodeB, an eNodeB (eNB), a
next-generation Node B or giga-nodeB (either of which may be
referred to as a gNB), a Home NodeB, a Home eNodeB, or some other
suitable terminology. Wireless communications system 100 may
include network devices 105 of different types (e.g., macro or
small cell base stations). The UEs 115 described herein may be able
to communicate with various types of network devices 105 and
network equipment including macro eNBs, small cell eNBs, gNBs,
relay network devices, and the like.
[0058] Each network device 105 may be associated with a particular
geographic coverage area 110 in which communications with various
UEs 115 is supported. Each network device 105 may provide
communication coverage for a respective geographic coverage area
110 via communication links 125, and communication links 125
between a network device 105 and a UE 115 may utilize one or more
carriers. Communication links 125 shown in wireless communications
system 100 may include uplink transmissions from a UE 115 to a
network device 105, or downlink transmissions from a network device
105 to a UE 115. Downlink transmissions may also be called forward
link transmissions while uplink transmissions may also be called
reverse link transmissions. A UE 115 may communicate with the core
network 130 through communication link 135.
[0059] The geographic coverage area 110 for a network device 105
may be divided into sectors making up only a portion of the
geographic coverage area 110, and each sector may be associated
with a cell. For example, each network device 105 may provide
communication coverage for a macro cell, a small cell, a hot spot,
or other types of cells, or various combinations thereof. In some
examples, a network device 105 may be movable and therefore provide
communication coverage for a moving geographic coverage area 110.
In some examples, different geographic coverage areas 110
associated with different technologies may overlap, and overlapping
geographic coverage areas 110 associated with different
technologies may be supported by the same network device 105 or by
different network devices 105. The wireless communications system
100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro
or NR network in which different types of network devices 105
provide coverage for various geographic coverage areas 110.
[0060] The term "cell" refers to a logical communication entity
used for communication with a network device 105 (e.g., over a
carrier), and may be associated with an identifier for
distinguishing neighboring cells (e.g., a physical cell identifier
(PCID), a virtual cell identifier (VCID)) operating via the same or
a different carrier. In some examples, a carrier may support
multiple cells, and different cells may be configured according to
different protocol types (e.g., machine-type communication (MTC),
narrowband Internet-of-Things (NB-IoT), enhanced mobile broadband
(eMBB), or others) that may provide access for different types of
devices. In some cases, the term "cell" may refer to a portion of a
geographic coverage area 110 (e.g., a sector) over which the
logical entity operates.
[0061] UEs 115 may be dispersed throughout the wireless
communications system 100, and each UE 115 may be stationary or
mobile. A UE 115 may also be referred to as a mobile device, a
wireless device, a remote device, a handheld device, or a
subscriber device, or some other suitable terminology, where the
"device" may also be referred to as a unit, a station, a terminal,
or a client. A UE 115 may be a personal electronic device such as a
cellular phone, a personal digital assistant (PDA), a tablet
computer, a laptop computer, or a personal computer. In some
examples, a UE 115 may also refer to a wireless local loop (WLL)
station, an Internet of Things (IoT) device, an Internet of
Everything (IoE) device, or an MTC device, or the like, which may
be implemented in various articles such as appliances, vehicles,
meters, or the like. A UE 115 may communicate with the core network
130 through communication link 135.
[0062] Some UEs 115, such as MTC or IoT devices, may be low cost or
low complexity devices, and may provide for automated communication
between machines (e.g., via Machine-to-Machine (M2M)
communication). M2M communication or MTC may refer to data
communication technologies that allow devices to communicate with
one another or a network device 105 without human intervention. In
some examples, M2M communication or MTC may include communications
from devices that integrate sensors or meters to measure or capture
information and relay that information to a central server or
application program that can make use of the information or present
the information to humans interacting with the program or
application. Some UEs 115 may be designed to collect information or
enable automated behavior of machines. Examples of applications for
MTC devices include smart metering, inventory monitoring, water
level monitoring, equipment monitoring, healthcare monitoring,
wildlife monitoring, weather and geological event monitoring, fleet
management and tracking, remote security sensing, physical access
control, and transaction-based business charging.
[0063] Some UEs 115 may be configured to employ operating modes
that reduce power consumption, such as half-duplex communications
(e.g., a mode that supports one-way communication via transmission
or reception, but not transmission and reception simultaneously).
In some examples, half-duplex communications may be performed at a
reduced peak rate. Other power conservation techniques for UEs 115
include entering a power saving "deep sleep" mode when not engaging
in active communications, or operating over a limited bandwidth
(e.g., according to narrowband communications). In some cases, UEs
115 may be designed to support critical functions (e.g., mission
critical functions), and a wireless communications system 100 may
be configured to provide ultra-reliable communications for these
functions.
[0064] In some cases, a UE 115 may also be able to communicate
directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or
device-to-device (D2D) protocol). One or more of a group of UEs 115
utilizing D2D communications may be within the geographic coverage
area 110 of a network device 105. Other UEs 115 in such a group may
be outside the geographic coverage area 110 of a network device
105, or be otherwise unable to receive transmissions from a network
device 105. In some cases, groups of UEs 115 communicating via D2D
communications may utilize a one-to-many (1:M) system in which each
UE 115 transmits to every other UE 115 in the group. In some cases,
a network device 105 facilitates the scheduling of resources for
D2D communications. In other cases, D2D communications are carried
out between UEs 115 without the involvement of a network device
105.
[0065] Network devices 105 may communicate with the core network
130 and with one another. For example, network devices 105 may
interface with the core network 130 through backhaul links 132
(e.g., via an S1, N2, N3, or other interface). Network devices 105
may communicate with one another over backhaul links 134 (e.g., via
an X2, Xn, or other interface) either directly (e.g., directly
between network devices 105) or indirectly (e.g., via core network
130).
[0066] Network devices 105 may support functionality for one or
more operations on an IAB network. For example, network devices 105
may be split into support entities (e.g., functionalities) for
promoting wireless backhaul density in collaboration with NR
communication access. In some cases, one or more network devices
105 may be split into associated central unit (CU) and distributed
unit (DU) entities, where one or more DUs may be partially
controlled by an associated CU. The CU entities of the one or more
network devices 105 (which CU may also be referred to as a control
node) may facilitate connection between the core network 130 and an
access node (e.g., via a wireline or wireless connection to the
core network). The DUs of the one or more network devices 105 may
control and/or schedule functionality for additional devices (e.g.,
one or more additional network devices 105, UEs 115) according to
configured access and backhaul links. Based on the supported
entities at the one or more network devices 105, the one or more
network devices 105 may be referred to as serving network devices
(e.g., or serving devices, or IAB donors, or relay nodes).
[0067] Additionally, in some cases, one or more network devices 105
may be split into associated MT and/or DU functionalities, where an
MT functionality of the one or more network devices 105 may be
controlled and/or scheduled by a DU entity corresponding to the one
or more different serving devices (e.g., via a UE interface). The
MT functionality may enable a network device 105 (e.g., access
node) to act like a UE (e.g., UE function (UEF)) and, as such,
receive transmissions from another access node via a backhaul
connection. The DU functionality may enable an access node to act
conventionally (e.g., access node function (ANF)) and transmit
messages to UEs and other access nodes (e.g., MTs). Additionally or
alternatively, the MTs and DUs may be physical components in a
respective access node. In addition, DUs of the one or more network
devices 105 may be partially controlled by signaling messages from
CU entities of associated serving devices on the configured access
and backhaul links of a network connection (e.g., via an
Fl-application protocol (AP)). The DUs of the one or more network
devices 105 may control and/or schedule functionality for
additional devices (e.g., MT entities of one or more alternative
network devices 105, UEs 115) according to configured access and
backhaul links. Based on the supported entities of the one or more
network devices 105, the network devices may be referred to as
intermediary network devices (e.g., or IAB nodes).
[0068] The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The core network 130
may be an evolved packet core (EPC), which may include at least one
mobility management entity (MME), at least one serving gateway
(S-GW), and at least one Packet Data Network (PDN) gateway (P-GW).
The MME may manage non-access stratum (e.g., control plane)
functions such as mobility, authentication, and bearer management
for UEs 115 served by network devices 105 associated with the EPC.
User IP packets may be transferred through the S-GW, which itself
may be connected to the P-GW. The P-GW may provide IP address
allocation as well as other functions. The P-GW may be connected to
the network operators IP services. The operators IP services may
include access to the Internet, Intranet(s), an IP Multimedia
Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.
[0069] At least some of the network devices, such as a network
device 105, may include subcomponents such as an access network
entity, which may be an example of an access node controller (ANC).
Each access network entity may communicate with UEs 115 through a
number of other access network transmission entities, which may be
referred to as a radio head, a smart radio head, or a
transmission/reception point (TRP). In some configurations, various
functions of each access network entity or network device 105 may
be distributed across various network devices (e.g., radio heads
and access network controllers) or consolidated into a single
network device (e.g., a network device 105).
[0070] Wireless communications system 100 may operate using one or
more frequency bands, typically in the range of 300 MHz to 300 GHz.
Generally, the region from 300 MHz to 3 GHz is known as the
ultra-high frequency (UHF) region or decimeter band, since the
wavelengths range from approximately one decimeter to one meter in
length. UHF waves may be blocked or redirected by buildings and
environmental features. However, the waves may penetrate structures
sufficiently for a macro cell to provide service to UEs 115 located
indoors. Transmission of UHF waves may be associated with smaller
antennas and shorter range (e.g., less than 100 km) compared to
transmission using the smaller frequencies and longer waves of the
high frequency (HF) or very high frequency (VHF) portion of the
spectrum below 300 MHz.
[0071] Wireless communications system 100 may also operate in a
super high frequency (SHF) region using frequency bands from 3 GHz
to 30 GHz, also known as the centimeter band. The SHF region
includes bands such as the 5 GHz industrial, scientific, and
medical (ISM) bands, which may be used opportunistically by devices
that can tolerate interference from other users.
[0072] Wireless communications system 100 may also operate in an
extremely high frequency (EHF) region of the spectrum (e.g., from
30 GHz to 300 GHz), also known as the millimeter band. In some
examples, wireless communications system 100 may support mmW
communications between UEs 115 and network devices 105, and EHF
antennas of the respective devices may be even smaller and more
closely spaced than UHF antennas. In some cases, this may
facilitate use of antenna arrays within a UE 115. However, the
propagation of EHF transmissions may be subject to even greater
atmospheric attenuation and shorter range than SHF or UHF
transmissions. Techniques disclosed herein may be employed across
transmissions that use one or more different frequency regions, and
designated use of bands across these frequency regions may differ
by country or regulating body.
[0073] In some cases, wireless communications system 100 may
utilize both licensed and unlicensed radio frequency spectrum
bands. For example, wireless communications system 100 may employ
License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access
technology, or NR technology in an unlicensed band such as the 5
GHz ISM band. When operating in unlicensed radio frequency spectrum
bands, wireless devices such as network devices 105 and UEs 115 may
employ listen-before-talk (LBT) procedures to ensure a frequency
channel is clear before transmitting data. In some cases,
operations in unlicensed bands may be based on a CA configuration
in conjunction with CCs operating in a licensed band (e.g., LAA).
Operations in unlicensed spectrum may include downlink
transmissions, uplink transmissions, peer-to-peer transmissions, or
a combination of these. Duplexing in unlicensed spectrum may be
based on frequency division duplexing (FDD), time division
duplexing (TDD), or a combination of both.
[0074] In some examples, network device 105 or UE 115 may be
equipped with multiple antennas, which may be used to employ
techniques such as transmit diversity, receive diversity,
multiple-input multiple-output (MIMO) communications, or
beamforming. For example, wireless communications system 100 may
use a transmission scheme between a transmitting device (e.g., a
network device 105) and a receiving device (e.g., a UE 115), where
the transmitting device is equipped with multiple antennas and the
receiving devices are equipped with one or more antennas. MIMO
communications may employ multipath signal propagation to increase
the spectral efficiency by transmitting or receiving multiple
signals via different spatial layers, which may be referred to as
spatial multiplexing. The multiple signals may, for example, be
transmitted by the transmitting device via different antennas or
different combinations of antennas. Likewise, the multiple signals
may be received by the receiving device via different antennas or
different combinations of antennas. Each of the multiple signals
may be referred to as a separate spatial stream, and may carry bits
associated with the same data stream (e.g., the same codeword) or
different data streams. Different spatial layers may be associated
with different antenna ports used for channel measurement and
reporting. MIMO techniques include single-user MIMO (SU-MIMO) where
multiple spatial layers are transmitted to the same receiving
device, and multiple-user MIMO (MU-MIMO) where multiple spatial
layers are transmitted to multiple devices.
[0075] Beamforming, which may also be referred to as spatial
filtering, directional transmission, or directional reception, is a
signal processing technique that may be used at a transmitting
device or a receiving device (e.g., a network device 105 or a UE
115) to shape or steer an antenna beam (e.g., a transmit beam or
receive beam) along a spatial path between the transmitting device
and the receiving device. Beamforming may be achieved by combining
the signals communicated via antenna elements of an antenna array
such that signals propagating at particular orientations with
respect to an antenna array experience constructive interference
while others experience destructive interference. The adjustment of
signals communicated via the antenna elements may include a
transmitting device or a receiving device applying certain
amplitude and phase offsets to signals carried via each of the
antenna elements associated with the device. The adjustments
associated with each of the antenna elements may be defined by a
beamforming weight set associated with a particular orientation
(e.g., with respect to the antenna array of the transmitting device
or receiving device, or with respect to some other
orientation).
[0076] In some cases, the antennas of a network device 105 or UE
115 may be located within one or more antenna arrays, which may
support MIMO operations, or transmit or receive beamforming. For
example, one or more base station antennas or antenna arrays may be
co-located at an antenna assembly, such as an antenna tower. In
some cases, antennas or antenna arrays associated with a network
device 105 may be located in diverse geographic locations. A
network device 105 may have an antenna array with a number of rows
and columns of antenna ports that the network device 105 may use to
support beamforming of communications with a UE 115. Likewise, a UE
115 may have one or more antenna arrays that may support various
MIMO or beamforming operations.
[0077] In some cases, wireless communications system 100 may be a
packet-based network that operate according to a layered protocol
stack. In the user plane, communications at the bearer or Packet
Data Convergence Protocol (PDCP) layer may be IP-based. A Radio
Link Control (RLC) layer may in some cases perform packet
segmentation and reassembly to communicate over logical channels. A
Medium Access Control (MAC) layer may perform priority handling and
multiplexing of logical channels into transport channels. The MAC
layer may also use hybrid automatic repeat request (HARQ) to
provide retransmission at the MAC layer to improve link efficiency.
In the control plane, the Radio Resource Control (RRC) protocol
layer may provide establishment, configuration, and maintenance of
an RRC connection between a UE 115 and a network device 105 or core
network 130 supporting radio bearers for user plane data. At the
Physical (PHY) layer, transport channels may be mapped to physical
channels.
[0078] In some cases, UEs 115 and network devices 105 may support
retransmissions of data to increase the likelihood that data is
received successfully. HARQ feedback is one technique of increasing
the likelihood that data is received correctly over a communication
link 125. HARQ may include a combination of error detection (e.g.,
using a cyclic redundancy check (CRC)), forward error correction
(FEC), and retransmission (e.g., automatic repeat request (ARQ)).
HARQ may improve throughput at the MAC layer in poor radio
conditions (e.g., signal-to-noise conditions). In some cases, a
wireless device may support same-slot HARQ feedback, where the
device may provide HARQ feedback in a specific slot for data
received in a previous symbol in the slot. In other cases, the
device may provide HARQ feedback in a subsequent slot, or according
to some other time interval.
[0079] Time intervals in LTE or NR may be expressed in multiples of
a basic time unit, which may, for example, refer to a sampling
period of T.sub.s=1/30,720,000 seconds. Time intervals of a
communications resource may be organized according to radio frames
each having a duration of 10 milliseconds (ms), where the frame
period may be expressed as T.sub.f=307,200 T.sub.s. The radio
frames may be identified by a system frame number (SFN) ranging
from 0 to 1023. Each frame may include 10 subframes numbered from 0
to 9, and each subframe may have a duration of 1 ms. A subframe may
be further divided into 2 slots each having a duration of 0.5 ms,
and each slot may contain 6 or 7 modulation symbol periods (e.g.,
depending on the length of the cyclic prefix prepended to each
symbol period). Excluding the cyclic prefix, each symbol period may
contain 2048 sampling periods. In some cases, a subframe may be the
smallest scheduling unit of the wireless communications system 100,
and may be referred to as a transmission time interval (TTI). In
other cases, a smallest scheduling unit of the wireless
communications system 100 may be shorter than a subframe or may be
dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or
in selected component carriers using sTTIs).
[0080] In some wireless communications systems, a slot may further
be divided into multiple mini-slots containing one or more symbols.
In some instances, a symbol of a mini-slot or a mini-slot may be
the smallest unit of scheduling. Each symbol may vary in duration
depending on the subcarrier spacing or frequency band of operation,
for example. Further, some wireless communications systems may
implement slot aggregation in which multiple slots or mini-slots
are aggregated together and used for communication between a UE 115
and a network device 105.
[0081] The term "carrier" refers to a set of radio frequency
spectrum resources having a defined physical layer structure for
supporting communications over a communication link 125. For
example, a carrier of a communication link 125 may include a
portion of a radio frequency spectrum band that is operated
according to physical layer channels for a given radio access
technology. Each physical layer channel may carry user data,
control information, or other signaling. A carrier may be
associated with a pre-defined frequency channel (e.g., an E-UTRA
absolute radio frequency channel number (EARFCN)), and may be
positioned according to a channel raster for discovery by UEs 115.
Carriers may be downlink or uplink (e.g., in an FDD mode), or be
configured to carry downlink and uplink communications (e.g., in a
TDD mode). In some examples, signal waveforms transmitted over a
carrier may be made up of multiple sub-carriers (e.g., using
multi-carrier modulation (MCM) techniques such as orthogonal
frequency division multiplexing (OFDM) or DFT-s-OFDM).
[0082] The organizational structure of the carriers may be
different for different radio access technologies (e.g., LTE,
LTE-A, LTE-A Pro, NR, etc.). For example, communications over a
carrier may be organized according to TTIs or slots, each of which
may include user data as well as control information or signaling
to support decoding the user data. A carrier may also include
dedicated acquisition signaling (e.g., synchronization signals or
system information, etc.) and control signaling that coordinates
operation for the carrier. In some examples (e.g., in a carrier
aggregation configuration), a carrier may also have acquisition
signaling or control signaling that coordinates operations for
other carriers.
[0083] Physical channels may be multiplexed on a carrier according
to various techniques. A physical control channel and a physical
data channel may be multiplexed on a downlink carrier, for example,
using time division multiplexing (TDM) techniques, frequency
division multiplexing (FDM) techniques, or hybrid TDM-FDM
techniques. In some examples, control information transmitted in a
physical control channel may be distributed between different
control regions in a cascaded manner (e.g., between a common
control region or common search space and one or more UE-specific
control regions or UE-specific search spaces).
[0084] A carrier may be associated with a particular bandwidth of
the radio frequency spectrum, and in some examples the carrier
bandwidth may be referred to as a "system bandwidth" of the carrier
or the wireless communications system 100. For example, the carrier
bandwidth may be one of a number of predetermined bandwidths for
carriers of a particular radio access technology (e.g., 1.4, 3, 5,
10, 15, 20, 40, or 80 MHz). In some examples, each served UE 115
may be configured for operating over portions or all of the carrier
bandwidth. In other examples, some UEs 115 may be configured for
operation using a narrowband protocol type that is associated with
a predefined portion or range (e.g., set of subcarriers or RBs)
within a carrier (e.g., "in-band" deployment of a narrowband
protocol type).
[0085] In a system employing MCM techniques, a resource element may
consist of one symbol period (e.g., a duration of one modulation
symbol) and one subcarrier, where the symbol period and subcarrier
spacing are inversely related. The number of bits carried by each
resource element may depend on the modulation scheme (e.g., the
order of the modulation scheme). Thus, the more resource elements
that a UE 115 receives and the higher the order of the modulation
scheme, the higher the data rate may be for the UE 115. In MIMO
systems, a wireless communications resource may refer to a
combination of a radio frequency spectrum resource, a time
resource, and a spatial resource (e.g., spatial layers), and the
use of multiple spatial layers may further increase the data rate
for communications with a UE 115.
[0086] In some wireless communications systems 100, one or more
network devices 105 (e.g., a serving device, a donor IAB node, a
relay node, a mobile parent, etc.) may include CUs and DUs, where
one or more DUs associated with a serving device may be partially
controlled by a CU associated with a serving device. The base
station CUs may be a component of a network management function,
database, data center, or the core network 130 (e.g., a 5G NR core
network (5GC)). In some cases, the base station CU may be in
communication with the network management function (e.g., in some
cases, the network management function may refer to a separate
entity in communication with the base station CU). A base station
CU may communicate with a serving device via a backhaul link 132
(e.g., a wireline backhaul or a wireless backhaul).
[0087] As another example, in IAB networks, a base station CU
(e.g., a serving device) may communicate with the core network 130
(e.g., the NGC) via a backhaul link 132 (e.g., a wireline backhaul
or wireless backhaul). The serving device may be referred to, for
example in an IAB network, as an IAB donor or relay node and may be
in communication with one or more IAB nodes (e.g., other network
devices 105) operating as base station DUs relative to the IAB
donor, and one or more UEs 115. For example, an IAB network may
include a chain of wireless devices (e.g., starting with the
serving device (a radio access network (RAN) node that terminates
an interface with the core network) and ending with a UE 115, with
any number of IAB nodes or relay nodes in between). IAB nodes
(e.g., relay network devices, relay nodes, etc.) may support MT
functionality (which may also be referred to as UEF) controlled and
scheduled by an IAB donor, or another parent IAB node. IAB nodes
(e.g., relay network devices, relay nodes, etc.) may also support
DU functionality (which may also be referred to as an ANF) relative
to additional entities (e.g., IAB nodes, UEs 115, etc.) within the
relay chain or configuration of the access network (e.g.,
downstream). In some cases, MT functionality may refer to an
implementation that supports at least some aspects of an MT or a UE
115. These relay mechanisms may forward traffic along to the
additional entities, extend the range of wireless access for one or
more network devices, enhance the density of backhaul capability
within serving cells, etc.
[0088] While mobile access may sometimes be associated with
single-hop communication links between a source and destination
(e.g., an asymmetric link), wireless backhaul communications may
support multi-hop transport and provide robustness through
topological redundancy (e.g., alternative paths for data exchange
within a wireless communications network). Accordingly, underlying
links using wireless backhaul communications may be symmetric in
nature and use large-scale resource coordination among the wireless
communication links.
[0089] When establishing a connection to a wireless access network,
one access node (e.g., operating as an MT) may synchronize to a
separate access node (e.g., operating as a DU) using an initial
access procedure over an access network (e.g., similar to a UE 115
establishing access to a network device 105). For example, a UE 115
may follow the initial access procedure to connect to a network
device 105 over the access network, where the MT (e.g., access node
operating as the MT) is analogous to the UE 115 and the DU (e.g.,
access node operating as the DU) is analogous to the network device
105. A serving device (e.g., a parent device, a base station, a DU,
an access node operating as a DU) may periodically transmit
synchronization signals (e.g., primary synchronization symbol
(PSS), secondary synchronization symbol (SSS), physical broadcast
channel (PBCH)), and a connecting device (e.g., a UE, an MT, an
access node operating as an MT) may search for these
synchronization signals. In some cases, the synchronization signals
may be specific to a radio access technology (RAT) for the wireless
communications system (e.g., synchronization signal blocks that
include NR-PSS, NR-SSS, NR-PBCH). Upon detection of the
synchronization signals, the connecting device may acquire the time
and frequency synchronization of the serving device, as well as
some system information.
[0090] After synchronizing (e.g., the connecting device decodes a
system information block (SIB) such as SIB2), the connecting device
may perform a RACH procedure to further establish the connection to
the wireless access network through the serving device. The RACH
procedure may involve the connecting device transmitting a message
including a RACH preamble (e.g., a message 1 (MSG1) or a message A
(msgA)) on a set of selected resources to inform the serving device
about the presence of the connecting device. For example, the RACH
preamble may be randomly selected from a set of 64 predetermined
sequences. The set of different sequences may enable the serving
device to distinguish between multiple connecting devices trying to
access the system simultaneously. Additionally, the connecting
device may request resources for further communications using the
RACH preamble. After receiving and in response to the RACH
preamble, the serving device may transmit a random access response
(RAR) (e.g., a message 2 (MSG2) or a message B (msgB)) to the
connecting device, where the serving device identifies the
connecting device based on the RACH preamble transmitted. The RAR
may provide an uplink resource grant, a timing advance, and a
temporary cell radio network temporary identity (C-RNTI).
[0091] In some cases, the connecting device may then transmit an
RRC connection request, or RACH message 3 (MSG3), along with a
temporary mobile subscriber identity (TMSI) (e.g., if the
connecting device has previously been connected to the same
wireless network) or a random identifier, after receiving the RAR.
The RRC connection request may also indicate the reason the
connecting device is connecting to the network (e.g., emergency,
signaling, data exchange). In some cases, the serving device may
respond to the connection request with a contention resolution
message, or RACH message 4 (MSG4), addressed to the connecting
device, which may provide a new C-RNTI. If the connecting device
receives a contention resolution message with the correct
identification, it may proceed with RRC setup. If the connecting
device does not receive a contention resolution message (e.g., if
there is a conflict with another connecting device), it may repeat
the RACH process by transmitting a message with a new RACH
preamble.
[0092] When determining the RACH preamble and the resources for
transmitting the RACH preamble, the connecting and serving devices
may take several factors into account. For example, the connecting
device may choose the RACH preamble from a group of available
preambles that the serving device indicates based on a number of
parameters included in a SIB (e.g., SIB2). The parameters may
include the total number of available RACH preambles, the number of
available RACH preambles in a first group (e.g., Group A), and a
corresponding message size for choosing a RACH preamble from the
first group. In some cases, the serving device may indicate two
groups (e.g., Group A and Group B) for the available RACH preambles
that the connecting device may use.
[0093] The connecting device may choose a RACH preamble from one of
the groups based on a random identifier (ID) corresponding to the
connecting device, the size of MSG3 or msgA (e.g., the required
resources to transmit MSG3 or msgA), or additional parameters. For
example, if the size of MSG3 is greater than the indicated message
size for the first group, the connecting device may select a RACH
preamble from the second group (e.g., Group B). The connecting
device may determine the group to use and randomly select the RACH
preamble from the corresponding group. Additionally, the connecting
device may choose resources for transmitting the RACH preamble
based on a location of a detected synchronization signal block
(SSB) (e.g., or a strongest detected SSB if multiple SSBs are
detected).
[0094] In some cases, resources used for one or more messages
transmitted during the RACH procedure (e.g., RACH resources) may be
multiplexed for connecting devices (e.g., access devices, UEs 115,
MTs). For example, the network may orthogonalize the RACH
transmissions in the time and frequency domain. Additionally, the
network may configure a given number of RACH preambles (e.g., 64)
for RACH resources that use the same time-frequency resources.
Since the connecting devices may use the same RACH resources, the
network may configure the different RACH preambles such that a
serving device may differentiate and identify different connecting
devices that may attempt to connect at the same time (e.g., and
transmit a RAR to the corresponding connecting device). The network
(e.g., CU) may select the number of RACH preamble formats and
corresponding durations to meet a RACH link budget of connecting
devices located at the edge of a cell (e.g., cell edge UEs 115,
MTs).
[0095] In some cases, connecting devices at the cell edge may use
longer RACH preambles to increase the chances that an identifiable
RACH preamble reaches the serving device (e.g., DU, access node
operating as a DU, base station), because signal energy levels may
drop between the connecting devices at the cell edge and the
serving device (e.g., due to path loss or other signal
attenuation). Accordingly, the network may determine a preamble
format needed to achieve effective communication with cell edge
devices and may use a corresponding RACH preamble for each
connecting device the network serves. Each connecting device may
perform open loop power control, such that the serving device
detects the RACH preamble transmission from each connecting device
at a same receive power. In some cases, a first connecting device
(e.g., a backhaul access node, MT) may have more power available
for a RACH preamble transmission than a second connecting device
(e.g., an access UE 115) based on differing factors between the
connecting devices (e.g., a number of antennas, available power,
etc.). As such, the network may diversify RACH preambles in order
to more efficiently use the power available for different
connecting devices.
[0096] In cases where a core network 130 has configured different
RACH preamble formats, these formats may be different for devices
connecting via backhaul links 134 (e.g., access nodes with MT
functionalities) and for devices (e.g., UEs 115) connecting via
communication links 125 (e.g., access links). For example, a
backhaul connecting device (e.g., access node with MT
functionality) may transmit using a same power as a cell edge UE
115 with more power budget to spare (e.g., due to more antennas
and/or greater power availability). In some examples, a different
RACH preamble format (e.g., backhaul RACH preamble format) may
support wireless communications system 100 to use the power
available to a backhaul connecting device and more efficiently use
shared time-frequency resources. In one example, wireless
communications system 100 may truncate or shorten backhaul RACH
preamble formats in comparison to the already-configured RACH
preamble formats (e.g., access RACH preambles formats). In some
cases, these shortened backhaul RACH preamble formats may support
multiple transmissions from backhaul connecting devices in the time
it takes for one transmission to occur from an access connecting
device. Additionally or alternatively, shortened backhaul RACH
preamble formats may allow one backhaul transmission and one access
transmission to occur at the same time, but with less
interference.
[0097] One or more of the network devices 105 (e.g., an access node
105, base station 105, etc.) may include a communications manager
101. In some cases, the network device 105 may function as an MT
(e.g., connecting device, first access node, etc.), where the MT is
attempting to connect to a DU or CU (e.g., serving device, second
access node, mobile parent, etc.). Accordingly, when functioning as
an MT, the communications manager 101 may receive, from the DU or
CU, configuration signaling indicating a shared RACH resource and a
backhaul RACH preamble format, where the backhaul RACH preamble
format differs from an access RACH preamble format. In some cases,
the communications manager 101 may then transmit, to the DU or CU,
a backhaul random access message in accordance with the backhaul
RACH preamble format and within the shared RACH resource. Based on
the backhaul random access message (e.g., and a corresponding RACH
procedure), the communications manager 101 may establish a backhaul
link with the DU or CU.
[0098] Additionally or alternatively, the base station 105 may
function as a DU or CU (e.g., serving device, first access node,
mobile parent, etc.), where the DU or CU provides information for
an MT (e.g., a second access node, a connecting device, etc.) to
perform a RACH procedure for subsequent communications.
Accordingly, when functioning as a DU or CU, communications manager
101 may transmit, to the MT, first configuration signaling
indicating a shared RACH resource and a backhaul RACH preamble
format. Additionally, the communications manager 101 may transmit,
to a UE 115, second configuration signaling indicating the shared
RACH resource and an access RACH preamble format, the backhaul RACH
preamble format differing from the access RACH preamble format. In
some cases, the communications manager 101 may then monitor the
shared RACH resource for at least one of a first random access
message in accordance with the backhaul RACH preamble format or a
second random access message in accordance with the access RACH
preamble format.
[0099] FIG. 2A illustrates an example of an IAB network 200 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. In some examples, IAB network
200 may implement aspects of wireless communications system 100.
IAB network 200 may include network devices 105 (e.g., access nodes
105, base stations 105, etc.) and supported devices (e.g., UEs 115,
MTs), where the network devices 105 may be split into one or more
support entities (e.g., functionalities) for promoting wireless
backhaul density in collaboration with NR communication access
(e.g., access traffic). Aspects of the supporting functionalities
of the network devices 105 may be referred to as IAB nodes. For
example, FIG. 2A illustrates an IAB network 200 that may include
one or more fiber point backhaul connections 205. For example, the
IAB network 200 may implement an IAB network by connecting each
access node (e.g., network devices 105) in the IAB network 200 to a
core network (e.g., such as the core network 130 as described above
with reference to FIG. 1) with a fiber point backhaul connection
205. Each network device 105 may communicate access traffic with
the one or more UEs 115 that it serves over an access network 210
via respective wireless access connections 220.
[0100] FIG. 2B illustrates an example of an IAB network 201 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. In some examples, IAB network
201 may implement aspects of wireless communications system 100.
IAB network 201 may include network devices 105 and/or supported
devices (e.g., UEs 115, MTs) split into one or more support
entities (e.g., functionalities) for promoting wireless backhaul
density in collaboration with NR communication access. Aspects of
the supporting functionalities of the network devices 105 may be
referred to as IAB nodes. For example, FIG. 2B illustrates an IAB
network 201 (e.g., an NR system) that may implement the IAB
architecture by connecting one access node (e.g., one network
device 105) in the IAB network 201 to the core network 130 via a
fiber point backhaul connection 205-f, while other network devices
105 in the IAB network 201 may exchange access traffic with fiber
point backhaul connection 205-f via a wireless backhaul network
215, using wireless backhaul connections 230. Each network device
105 may communicate access traffic with the one or more UEs 115
that it serves over access network 210 via wireless access
connections 220.
[0101] FIG. 2C illustrates an example of an IAB network 202 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. In some examples, IAB network
202 may implement aspects of wireless communications system 100.
IAB network 202 may include network devices 105 or supported
devices (e.g., UEs 115, MTs) split into one or more support
entities (e.g., functionalities) for promoting wireless backhaul
density in collaboration with NR communication access. Aspects of
the supporting functionalities of the network devices 105 may be
referred to as IAB nodes. For example, FIG. 2C illustrates an IAB
network 202 (e.g., an NR system) that may implement the IAB
architecture by connecting one access node (e.g., one network
device 105) in the IAB network 202 to the core network 130 via a
fiber point backhaul connection 205-g, while other network devices
105 in the IAB network 202 may exchange access traffic with the
fiber point backhaul connection 205-g via a wireless backhaul
network 215, using beamformed (e.g., a pencil-beam) wireless
backhaul connections 235. Each network device 105 may communicate
access traffic with the one or more UEs 115 that it serves over
access network 210 via beamformed (e.g., pencil-beam) wireless
access connections 225.
[0102] FIG. 3 illustrates an example of a resource partitioning
scheme 300 that supports a modified backhaul RACH in accordance
with one or more aspects of the present disclosure. In some
examples, resource partitioning scheme 300 may implement aspects of
wireless communications system 100. Resource partitioning scheme
may include an anchor node 305 (e.g., an access node with CU
functionality) that is coupled with wireline backhaul link 310
(e.g., fiber point backhaul connection) to provide interfaces to a
core network 130 for a system. Further, backhaul and/or access
links may connect anchor node 305 to one or more access nodes 315
and/or UEs 115 (e.g., UEs 115-a, 115-b, and 115-c), respectively,
which may relay information or be further connected to additional
access nodes 315 and UEs 115 over additional backhaul and/or access
links (e.g., according to IAB networks 200, 201, and/or 202 of FIG.
2). The backhaul and/or access links may include wireless links.
Each access node 315 may include an ANF (e.g., DU functionality),
UEF (e.g., MT functionality), routing table (RT), or a combination
thereof. An RT may examine a received data packet and forward the
packet along a path of the IAB network toward a specified IP
address of the packet's destination.
[0103] In some cases, anchor node 305 may be connected to a first
set of nodes over links 320. For example, anchor node 305 may
communicate with a UE 115-a over link 320-a, an access node 315-a
over link 320-b, and an access node 315-b over link 320-c. Because
access nodes 315-a and 315-b include a DU functionality, they may
further be connected to a second set of nodes over links 325 and
330, respectively. For example, access node 315-a may communicate
with a UE 115-b over link 325-a, an access node 315-c over link
325-b, and an access node 315-d over link 325-c. Additionally,
access node 315-b may communicate with access node 315-e over link
330. Similarly, access node 315-d may further include a DU
functionality and be connected to a third set of nodes over links
335. For example, access node 315-d may communicate with a UE 115-c
over link 335-a, access node 315-f over link 335-b, and access node
315-g over link 335-c.
[0104] A set of time-frequency resources may be partitioned for all
or some of the links between the anchor node 305, access nodes 315,
and UEs 115. For example, the set of time-frequency resources may
be partitioned into two sets for downlink and/or uplink data
transmissions (e.g., downlink/uplink resources 340 and 345). The
time-frequency resources may be partitioned based on the time
domain (e.g., a number of symbols for each set), where the sets
alternate according to defined repetition pattern. The first set of
resources may include downlink/uplink resources 340-a, 340-b, and
340-c. Additionally or alternatively, the second set of resources
may include downlink/uplink resources 345-a and 345-b.
[0105] Each set of resources may be allocated to corresponding
links and may alternate for each communication level. For example,
links 320 may utilize the first set of downlink/uplink resources
340, links 325 and 330 may utilize the second set of
downlink/uplink resources 345, and links 335 may utilize the first
set of downlink/uplink resources 340. Within a star (e.g., a node
and its links), an access node 315 that includes a DU functionality
may allocate the resources to each of the constituent links of the
access node 315 (e.g., access node 315-d may allocate resources of
the first set of downlink/uplink resources 340 for each link 335).
By employing resource partitioning scheme 300, the wireless system
may overcome constraints associated with half-duplex operations.
For example, access node 315-a may receive communications from
anchor node 305 over the first set of downlink/uplink resources 340
at a first time and may transmit communications on links 325 over
the second set of downlink/uplink resources 345 at a second time.
In some cases, an access node 315 that includes a DU functionality
may further allocate the resources according to a traffic type.
[0106] FIG. 4 illustrates an example of a wireless communications
system 400 that supports a modified backhaul RACH in accordance
with one or more aspects of the present disclosure. In some
examples, wireless communications system 400 may implement aspects
of wireless communications system 100. To accommodate different
devices, the wireless system may configure a multiplexing scheme
that includes RACH preambles and resources for access connecting
devices (e.g., UEs 115) and for backhaul connecting devices (e.g.,
backhaul node, an access node acting as an MT). In some aspects of
the disclosure, a UE 115 may be referred to as an access connecting
device 115, a network device 105 using MT capability may be
referred to as a backhaul connecting device 105, and a network
device 105 using DU and/or CU capability may be referred to as a
serving device 105. In some examples, an access connecting device
115-d (e.g., a UE 115) and a backhaul connecting device 105-e may
initiate a RACH procedure to connect to a same serving device
105-d.
[0107] Wireless RACH preamble transmissions (e.g., MSG1 of a random
access procedure) sent from the access connecting device 115-d
(e.g., via access RACH transmission 405) and from the backhaul
connecting device 105-e (e.g., via backhaul link 134-a) may occupy
the same RACH resources 410. However, a backhaul RACH preamble 415
may not be as long as an access RACH preamble 420 because a
backhaul connecting device may transmit at a higher power. For
example, the backhaul connecting device 105-e may be located
farther from serving device 105-d (e.g., to which connecting device
105-e is transmitting) than access connecting device 115-d and may
include a higher number of antennas than access connecting device
115-d. Accordingly, the backhaul connecting device 105-e may
transmit a RACH preamble at a higher power (e.g., based on the
higher number of antennas or transmit power at the disposal of the
backhaul connecting device 105-e), while still meeting a RACH link
budget for the connecting devices.
[0108] In one example, backhaul connecting device 105-e may be
located twice as far away from the serving device 105-d than a
farthest access connecting device 115-d (e.g., at the edge of
geographic coverage areas 110-a and 110-b) communicating with the
serving device 105-d. As such, the backhaul connecting device 105-e
may experience, for example, a 10 dB signal attenuation due to path
loss, but may be able to send a signal 20 dB stronger than the
signal from access connecting device 115-d (e.g., because the
backhaul connecting device 105-e has access to more transmit power
and, for example, 16 times the number of antennas as the access
connecting device 115-d). Therefore, the total link budget of the
backhaul connecting device 105-e may be 10 dB higher than that of
the access connecting device 115-d (e.g., where the system may base
RACH preambles on the link budget of access connecting devices
115).
[0109] Accordingly, the system may configure RACH preambles for
backhaul connecting devices 105 (e.g., backhaul RACH preambles or
transmissions) to be different than the RACH preambles for access
connecting devices 115 (e.g., access RACH preambles or
transmissions), based on the higher transmit power and higher link
budget. In one example, backhaul RACH preambles 415 may be a subset
of (e.g., use less resources than) an access RACH preamble 420. For
example, multiple backhaul RACH transmissions may coincide with one
access RACH transmission. This configuration may support multiple
(e.g., more than one) backhaul connecting devices transmitting RACH
preambles during one access RACH transmission. In some cases, this
configuration may support multiple backhaul connecting devices 105
connecting to a serving device 105 within one access RACH
transmission and/or for a backhaul connecting device 105 to connect
to the serving device 105 faster than an access device 115.
[0110] The system may use a backhaul preamble format (e.g.,
backhaul RACH preamble) that is different from an access preamble
format (e.g., based on the improved link budget for backhaul RACH
transmissions). For example, the system may use a backhaul RACH
preamble format that is a truncated version of an access preamble
format. Additionally or alternatively, the system may use a
backhaul RACH preamble format that is the same size as an access
preamble format. For example, the backhaul RACH preamble format may
indicate that the backhaul RACH preamble 415 may have the same
number of symbols as the access RACH preamble 420. Accordingly, the
system may configure the backhaul connecting device 105-e and the
access connecting device 115-d to include different control
information in their corresponding RACH transmissions to enable the
serving device 105-d to distinguish the RACH transmissions received
in the same RACH resources 410 from the respective devices.
[0111] In some examples, the system may indicate a set of backhaul
RACH preamble formats similar to a way in which the system
indicates the set of access RACH preamble formats, as discussed
above. The system (e.g., via a DU, CU, or core network 130) may
select and signal a set of backhaul RACH preamble formats for
serving device 105-d (e.g., an access node or DU) to choose from
for a RACH process. The serving device 105-d may choose from the
set of backhaul RACH preamble formats based on system conditions
(e.g., traffic, connectivity, interference). Additionally or
alternatively, the serving device 105-d may select a set of
backhaul RACH preamble formats for serving device 105-d. Following
the selection of backhaul RACH preamble formats, serving device
105-d may signal the set of backhaul RACH preamble formats to
connecting devices (e.g., UE 115-d, network device 105-e). In some
cases, the backhaul RACH preamble formats may be configured as
mini-slot durations of one, two, four, or six symbols, and may be
confined within a time configured for an access RACH preamble
format.
[0112] For example, the system may configure an access RACH
preamble format that spans 12 symbols and may configure a backhaul
RACH preamble format that spans four symbols. As such, three
backhaul RACH occasions 425 (e.g., opportunities to send a backhaul
RACH preamble) may exist for a single access RACH occasion (e.g.,
the access RACH preamble 420 may be the same duration as the three
backhaul RACH occasions 425). An access node (e.g., MT or DU) may
select one of the three backhaul RACH occasions 425 to use. In some
cases, three backhaul connecting devices 105 may transmit a
backhaul RACH preamble 415 in the time it takes to transmit one
access RACH preamble 420, a single backhaul connecting device 105-e
may transmit three backhaul RACH preambles 415 within the same
amount of time as an access RACH occasion, or a combination thereof
may occur. It is to be understood that the system may use backhaul
RACH preamble formats with different lengths than the examples as
described herein (e.g., in addition to the three-symbol backhaul
RACH format). Additionally, the system may restrict a backhaul RACH
occasion 425 (e.g., a last backhaul RACH occasion 425-c) from a set
of backhaul RACH occasions 425 within a shared RACH resource 410 to
minimize interference with future symbols. In some cases, the
system (e.g., DU or CU) may send a signal restricting or
prohibiting the last backhaul RACH occasion 425-c to assure the
backhaul RACH preamble 415 does not leak into the next symbol. For
example, the system may prohibit the last backhaul RACH occasion
425-c based on a longer round-trip time between the backhaul
connecting device 105-e and the serving device 105-d. In this case,
the transmission may take longer to propagate from backhaul
connecting device 105-e to the serving device 105-d than a
transmission from access connecting device 115-d. In some cases,
the backhaul RACH occasion 425-c may be greater than a guard
period, creating the potential for inter-symbol interference
between the backhaul RACH preamble 415 and transmissions following
backhaul RACH preamble 415.
[0113] As described herein, a truncated backhaul RACH preamble 415
may randomize and reduce collisions between access RACH
transmissions 405 and backhaul RACH transmissions (e.g., via
backhaul link 134-a) because the truncated backhaul RACH occasions
425 may coincide and interfere with only a portion of the access
RACH occasion rather than the entire access RACH preamble 420.
Further, a receiver (e.g., serving device 105-d, DU) may employ an
energy detection algorithm that may first detect backhaul RACH
transmissions (e.g., via backhaul link 134-a) and then detect any
access RACH transmissions 405. As such, the receiver may ensure
that the backhaul RACH transmissions do not interfere with the
access RACH transmissions 405 due to the higher power with which
the backhaul RACH transmissions are transmitted.
[0114] When using a shortened backhaul RACH preamble format in
comparison to an access RACH preamble format, backhaul connecting
device 105-e may convey additional information using the backhaul
RACH preamble 415. For example, the choice of a backhaul RACH
preamble 415 may convey data such as information regarding devices
(e.g., nodes) downstream (e.g., additional MTs, UEs) of the
connecting device 105 that is transmitting the backhaul RACH
preamble 415. For example, a serving device 105-d may indicate that
a set of different backhaul RACH occasions 425 exist within a
shared RACH resource 410. Backhaul connecting device 105-e may
identify a number of downstream nodes and select a backhaul RACH
occasion (e.g., backhaul RACH occasion 425-a) from the indicated
set based on the number of downstream nodes. In one example, of
indicating information via a backhaul RACH occasion 425, a backhaul
connecting device 105-e may transmit in the first backhaul RACH
occasion 425-a if there are no downstream nodes, transmit in
backhaul RACH occasion 425-b if there is a single downstream node,
or transmit in backhaul RACH occasion 425-c if there are two or
more downstream nodes.
[0115] FIG. 5 illustrates an example of an energy detection
algorithm 500 that supports a modified backhaul RACH in accordance
with one or more aspects of the present disclosure. In some
examples, energy detection algorithm 500 may implement aspects of
wireless communications systems 100 and/or 400. Energy detection
algorithm 500 may be implemented by hardware, software, or a
combination thereof included in device 505 (e.g., an access node,
DU functionality within an access node, a serving device). In one
example, a device antenna 510 may receive a signal 515 that
includes mixtures of signals from one or more backhaul connecting
devices and/or one or more access connecting devices. Additionally,
the received signal 515 may include parts of a backhaul RACH
preamble and/or parts of an access RACH preamble.
[0116] Device 505 may route information received in signal 515
through sub-algorithm 520 to identify parts of the received signal
515 that may correspond to a backhaul RACH preamble 525. Device 505
may then route the received signal 515 and identified backhaul RACH
preamble 525 through a differencing algorithm 530 to subtract the
parts of the signal corresponding to the backhaul RACH preamble 525
from the received signal 515. In some examples, signal 515 may
include parts of an access RACH preamble, and differencing
algorithm 530 may produce signal information related to access RACH
preamble 535. In some cases, the resulting information may contain
all or part of access RACH preamble 535.
[0117] FIG. 6 illustrates an example of a process flow 600 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. In some examples, process flow
600 may implement aspects of wireless communications systems 100
and/or 400. In some aspects of the disclosure a network device 105
using MT capability may be referred to as a backhaul connecting
device 105, and a network device 105 using DU and/or CU capability
may be referred to as a serving device 105. Process flow 600 may
include a backhaul connecting device 105-f, a serving device 105-g,
and a UE 115-e (e.g., an access connecting device 115), which may
be examples of corresponding devices (e.g., access nodes and UEs
115) as described with reference to FIGS. 1-5.
[0118] In the following description of the process flow 600, the
operations between backhaul connecting device 105-f, serving device
105-g, and UE 115-e may be transmitted in a different order than
the exemplary order shown, or the operations performed by backhaul
connecting device 105-f, serving device 105-g, and UE 115-e may be
performed in different orders or at different times. Certain
operations may also be left out of the process flow 600, or other
operations may be added to the process flow 600. It is to be
understood that while backhaul connecting device 105-f and serving
device 105-g are shown performing a number of the operations of
process flow 600, any wireless device may perform the operations
shown.
[0119] At 605, serving device 105-g (e.g., a network device serving
device 105-g, mobile parent, access node with DU and/or CU
functionality, etc.) may transmit a first configuration signaling
to backhaul connecting device 105-f (e.g., a network device, an
access node with MT functionality, an MT, etc.) indicating a shared
RACH resource (e.g., a RACH resource that is a time and frequency
resource useable for both access and backhaul communications) and a
backhaul RACH preamble format, the backhaul RACH preamble format
differing from an access RACH preamble format. In some examples,
the first configuration signaling may indicate a set of different
backhaul RACH occasions within the shared RACH resource.
Additionally, the first configuration signaling may indicate a
prohibited backhaul RACH occasion within the set of different
backhaul RACH occasions.
[0120] In some examples, the first configuration signaling may
indicate a number of symbols in the backhaul RACH preamble format,
the number of symbols being fewer than a number of symbols in the
access RACH preamble format. Additionally or alternatively, the
first configuration signaling may indicate a number of symbols in
the backhaul RACH preamble format, the number of symbols being the
same as a number of symbols in the access RACH preamble format. In
some examples, the first configuration signaling may indicate a
first parameter for received power for a backhaul random access
message configured for transmission by the backhaul connecting
device 105-f, the first parameter for received power exceeding a
second parameter for received power for an access random access
message configured for transmission by UE 115-e.
[0121] At 610, the serving device 105-g may further transmit a
second configuration signaling to UE 115-e, indicating the shared
RACH resource and an access RACH preamble format, the backhaul RACH
preamble format differing from the access RACH preamble format. At
615, after transmitting the first configuration signaling and the
second configuration signaling, the serving device 105-g may
monitor the shared RACH resource for at least one of a backhaul
random access message, in accordance with the backhaul RACH
preamble format, or an access random access message, in accordance
with the access RACH preamble format.
[0122] At 620, the backhaul connecting device 105-f may select a
backhaul RACH occasion from the set of different backhaul RACH
occasions, where a backhaul random access message may be
transmitted within the backhaul RACH occasion. Additionally,
selecting the backhaul RACH occasion may further include
identifying a number of downstream access nodes and selecting the
backhaul RACH occasion from the set of different backhaul RACH
occasions based on the number of downstream access nodes.
[0123] At 625, the backhaul connecting device 105-f may select a
transmission power for the backhaul random access message based on
the first parameter for received power, the first parameter for
received power exceeding the second parameter for received power
for an access random access message configured for transmission by
UE 115-e.
[0124] At 630, the backhaul connecting device 105-f may transmit,
to the serving device 105-g, a backhaul random access message in
accordance with the backhaul RACH preamble format and within the
shared RACH resource. For example, the backhaul connecting device
105-f may transmit the backhaul random access message with a number
of symbols fewer than a number of symbols of an access random
access message (e.g., a truncated number of resources/symbols).
Additionally or alternatively, the backhaul connecting device 105-f
may transmit the backhaul random access message with a number of
symbols the same as a number of symbols in an access random access
message with a different format.
[0125] In some examples, the backhaul connecting device 105-f may
transmit the random access message in accordance with the
transmission power selected at 625. Additionally or alternatively,
the backhaul connecting device 105-f may transmit the random access
message as a beamformed transmission via one or more antennas. In
some cases, the serving device 105-g may identify information from
the backhaul random access message based on the backhaul RACH
occasion selected by the backhaul connecting device 105-f at 620.
Such information, in some cases, may include identifying a number
of downstream access nodes based on the backhaul RACH occasion
selected by the backhaul connecting device 105-f at 620.
[0126] At 635, UE 115-e may transmit, to the serving device 105-g,
an access random access message in accordance with the access RACH
preamble format within the shared RACH resource. In some cases, the
serving device 105-g may receive the backhaul random access message
and the access random access message within the same shared RACH
resource.
[0127] At 640, receiving the access random access message may
further include detecting, using an energy detection algorithm, a
signal that includes the backhaul random access message in
accordance with the backhaul RACH preamble format within the shared
RACH resource. Accordingly, the serving device 105-g may generate a
modified signal by removing the backhaul random access message from
the signal. The serving device 105-g may process the modified
signal to obtain the access random access message.
[0128] At 645, after receiving the backhaul random access message,
the serving device 105-g may establish a backhaul link with the
connecting device 105-f based on the backhaul random access
message. Additionally or alternatively, after receiving access the
random access message, the serving device 105-g may establish an
access link with UE 115-e based on the access random access message
635.
[0129] FIG. 7 shows a block diagram 700 of a device 705 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The device 705 may be an example
of aspects of a base station 105, a network device 105, an access
node 105, a connecting device (e.g., an MT), or a serving device
(e.g., a mobile parent, a DU, a CU, etc.) as described herein. The
device 705 may include a receiver 710, a communications manager
715, and a transmitter 720. The device 705 may also include a
processor. Each of these components may be in communication with
one another (e.g., via one or more buses).
[0130] The receiver 710 may receive information such as packets,
user data, or control information associated with various
information channels (e.g., control channels, data channels, and
information related to modified backhaul RACH, etc.). Information
may be passed on to other components of the device 705. The
receiver 710 may be an example of aspects of the transceiver 1020
described with reference to FIG. 10. The receiver 710 may utilize a
single antenna or a set of antennas.
[0131] The communications manager 715 may include various features,
as described below. Some features may be used when the device 705
is acting as an MT (e.g., access node, connecting device, etc.),
while other features may be used when the device 705 is acting as a
DU or CU (e.g., access node, serving device, mobile parent, etc.).
For example, when acting as part of an MT (e.g., a first access
node in an IAB, a connecting device, etc.), the communications
manager 715 may receive, from a DU or CU (e.g., second access node,
serving device, DU, etc.), configuration signaling indicating a
shared RACH resource and a backhaul RACH preamble format, the
backhaul RACH preamble format differing from an access RACH
preamble format. Accordingly, the communications manager 715 may
transmit, to the DU or CU, a backhaul random access message in
accordance with the backhaul RACH preamble format within the shared
RACH resource. In some cases, the communications manager 715 may
establish a backhaul link with the DU or CU based on the backhaul
random access message.
[0132] Additionally or alternatively, when operating as part of a
DU or CU (e.g., a first access node in an IAB, serving device,
mobile parent, etc.), the communications manager 715 may transmit,
to an MT (e.g., a second access node, a connecting device, etc.),
first configuration signaling indicating a shared RACH resource and
a backhaul RACH preamble format. Additionally, the communications
manager 715 may transmit, to a UE, second configuration signaling
indicating the shared RACH resource and an access RACH preamble
format, the backhaul RACH preamble format differing from the access
RACH preamble format. Accordingly, the communications manager 715
may monitor the shared RACH resource for at least one of a first
random access message in accordance with the backhaul RACH preamble
format or a second random access message in accordance with the
access RACH preamble format. The communications manager 715 may be
an example of aspects of the communications manager 1010 described
herein.
[0133] The communications manager 715, or its sub-components, may
be implemented in hardware, code (e.g., software or firmware)
executed by a processor, or any combination thereof. If implemented
in code executed by a processor, the functions of the
communications manager 715, or its sub-components may be executed
by a general-purpose processor, a digital signal processor (DSP),
an application-specific integrated circuit (ASIC), a
field-programmable gate array (FPGA) or other programmable logic
device (PLD), discrete gate or transistor logic, discrete hardware
components, or any combination thereof designed to perform the
functions described in the present disclosure.
[0134] The communications manager 715, or its sub-components, may
be physically located at various positions, including being
distributed such that portions of functions are implemented at
different physical locations by one or more physical components. In
some examples, the communications manager 715, or its
sub-components, may be a separate and distinct component in
accordance with various aspects of the present disclosure. In some
examples, the communications manager 715, or its sub-components,
may be combined with one or more other hardware components,
including but not limited to an input/output (I/O) component, a
transceiver, a network server, another computing device, one or
more other components described in the present disclosure, or a
combination thereof in accordance with various aspects of the
present disclosure.
[0135] The transmitter 720 may transmit signals generated by other
components of the device 705. In some examples, the transmitter 720
may be collocated with a receiver 710 in a transceiver module. For
example, the transmitter 720 may be an example of aspects of the
transceiver 1020 described with reference to FIG. 10. The
transmitter 720 may utilize a single antenna or a set of
antennas.
[0136] The actions performed by the communications manager 715 as
described herein may be implemented to realize one or more
potential advantages. For example, communications manager 715 may
increase communication reliability and decrease communication
latency at a wireless device (e.g., a UE 115, an access node, or
one or more access node functionalities) by enabling modified RACH
preamble formats (e.g., for back random access procedures). The
modified RACH preamble formats may reduce transmission delays,
improve communication accuracy, and reduce collisions or
interference compared to other systems and techniques.
Communications manager 715 may save power and increase battery life
at a wireless device (e.g., a UE 115 or an access node) by
strategically reducing transmission delays and interference, among
other advantages.
[0137] FIG. 8 shows a block diagram 800 of a device 805 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The device 805 may be an example
of aspects of a device 705, a base station 105, a network device
105, an access node 105, a connecting device (e.g., an MT), or a
serving device (e.g., a mobile parent, a DU, a CU, etc.) as
described herein. The device 805 may include a receiver 810, a
communications manager 815, and a transmitter 840. The device 805
may also include a processor. Each of these components may be in
communication with one another (e.g., via one or more buses).
[0138] The receiver 810 may receive information such as packets,
user data, or control information associated with various
information channels (e.g., control channels, data channels, and
information related to modified backhaul RACH, etc.). Information
may be passed on to other components of the device 805. The
receiver 810 may be an example of aspects of the transceiver 1020
described with reference to FIG. 10. The receiver 810 may utilize a
single antenna or a set of antennas.
[0139] The communications manager 815 may be an example of aspects
of the communications manager 715 as described herein. The
communications manager 815 may include various features, as
described below. Some features may be used when the device 805 is
acting as an MT (e.g., access node, connecting device, etc.), while
other features may be used when the device 805 is acting as a DU or
CU (e.g., access node, serving device, mobile parent, etc.). The
communications manager 815 may include a RACH configuration
component 820, a backhaul RACH communicator 825, a backhaul link
establishment component 830, and a RACH monitoring component 835.
The communications manager 815 may be an example of aspects of the
communications manager 1010 described herein.
[0140] When the device 805 is acting as an MT, the communications
manager 815 may include and use a RACH configuration component 820.
The RACH configuration component 820 may receive, from a DU or CU
(e.g., second access node, serving device, mobile parent, etc.),
configuration signaling indicating a shared RACH resource and a
backhaul RACH preamble format, the backhaul RACH preamble format
differing from an access RACH preamble format.
[0141] When the device 805 is acting as an MT, the communications
manager 815 may include and use a backhaul RACH communicator 825.
The backhaul RACH communicator 825 may transmit, to the DU or CU, a
backhaul random access message in accordance with the backhaul RACH
preamble format within the shared RACH resource.
[0142] When the device 805 is acting as an MT, the communications
manager 815 may include and use a backhaul link establishment
component 830. The backhaul link establishment component 830 may
establish a backhaul link with the DU or CU based on the backhaul
random access message.
[0143] When the device 805 is acting as a DU or CU, the
communications manager 815 may include and use a RACH configuration
component 820. The RACH configuration component 820 may transmit,
to an MT (e.g., a second access node, a connecting device, etc.),
first configuration signaling indicating a shared RACH resource and
a backhaul RACH preamble format. Additionally, the RACH
configuration component 820 may transmit, to a UE, second
configuration signaling indicating the shared RACH resource and an
access RACH preamble format, the backhaul RACH preamble format
differing from the access RACH preamble format.
[0144] When the device 805 is acting as a DU or CU, the
communications manager 815 may include and use a RACH monitoring
component 835. The RACH monitoring component 835 may monitor the
shared RACH resource for at least one of a first random access
message in accordance with the backhaul RACH preamble format or a
second random access message in accordance with the access RACH
preamble format.
[0145] The transmitter 840 may transmit signals generated by other
components of the device 805. In some examples, the transmitter 840
may be collocated with a receiver 810 in a transceiver module. For
example, the transmitter 840 may be an example of aspects of the
transceiver 1020 described with reference to FIG. 10. The
transmitter 840 may utilize a single antenna or a set of
antennas.
[0146] A processor of a wireless device (e.g., controlling the
receiver 810, the transmitter 840, or the transceiver 1020 as
described with reference to FIG. 10) may increase communication
reliability and accuracy by enabling the wireless device to reduce
latency associated with random access procedures within a network.
The reduced latency may reduce transmission delays and overhead
(e.g., via implementation of system components described with
reference to FIG. 9) compared to other systems and techniques.
Further, the processor of the wireless device may identify one or
more aspects of a RACH preamble format (e.g., a backhaul RACH
preamble format) to perform the processes described herein. The
processor of the wireless device may use the RACH preamble format
to perform one or more actions that may result in higher
communication accuracy and communication reliability, as well as
save power and increase battery life at the wireless device (e.g.,
by reducing transmission delays and interference, improving network
coordination, and decreasing signaling time), among other
benefits.
[0147] FIG. 9 shows a block diagram 900 of a communications manager
905 that supports a modified backhaul RACH in accordance with one
or more aspects of the present disclosure. The communications
manager 905 may be an example of aspects of a communications
manager 715, a communications manager 815, or a communications
manager 1010 described herein. The communications manager 905 may
include various features, as described below, for a device, where
some features may be used when the device is acting as an MT (e.g.,
access node, connecting device, etc.), and other features may be
used when the device is acting as a DU or CU (e.g., access node,
serving device, mobile parent, etc.). The communications manager
905 may include a RACH configuration component 910, a backhaul RACH
communicator 915, a backhaul link establishment component 920, a
backhaul RACH occasion component 925, a backhaul RACH occasion
selector 930, a prohibited backhaul RACH occasion component 935, a
backhaul RACH transmission power component 940, a RACH monitoring
component 945, and an access RACH component 950. Each of these
modules may communicate, directly or indirectly, with one another
(e.g., via one or more buses).
[0148] When the device is acting as an MT (e.g., a first access
node in an IAB), the communications manager 905 may include and use
a RACH configuration component 910. The RACH configuration
component 910 may receive, from a DU or CU (e.g., a second access
node, a serving device, a mobile parent, etc.), configuration
signaling indicating a shared RACH resource and a backhaul RACH
preamble format, the backhaul RACH preamble format differing from
an access RACH preamble format. In some examples, the RACH
configuration component 910 may receive the configuration signaling
indicating a number of symbols in the backhaul RACH preamble
format, the number of symbols being fewer than a number of symbols
in the access RACH preamble format. Additionally or alternatively,
the RACH configuration component 910 may receive the configuration
signaling indicating a number of symbols in the backhaul RACH
preamble format, the number of symbols being the same as a number
of symbols in the access RACH preamble format. In some cases, the
shared RACH resource may be a time and frequency resource useable
for both access and backhaul communications.
[0149] When the device is acting as an MT, the communications
manager 905 may include and use a backhaul RACH communicator 915.
The backhaul RACH communicator 915 may transmit, to the DU or CU, a
backhaul random access message in accordance with the backhaul RACH
preamble format within the shared RACH resource. In some examples,
the backhaul RACH communicator 915 may transmit, via a set of
antennas, the backhaul random access message as a beamformed
transmission.
[0150] When the device is acting as an MT, the communications
manager 905 may include and use a backhaul link establishment
component 920. The backhaul link establishment component 920 may
establish a backhaul link with the DU or CU based on the backhaul
random access message.
[0151] When the device is acting as an MT, the communications
manager 905 may include and use a backhaul RACH occasion component
925. The backhaul RACH occasion component 925 may receive the
configuration signaling indicating a set of different backhaul RACH
occasions within the shared RACH resource.
[0152] When the device is acting as an MT, the communications
manager 905 may include and use a backhaul RACH occasion selector
930. The backhaul RACH occasion selector 930 may select a first
backhaul RACH occasion from the set of different backhaul RACH
occasions, where the backhaul random access message is transmitted
within the first backhaul RACH occasion. In some examples, the
backhaul RACH occasion selector 930 may identify a number of
downstream access nodes and may select the first backhaul RACH
occasion from the set of different backhaul RACH occasions based on
the number of downstream access nodes.
[0153] When the device is acting as an MT, the communications
manager 905 may include and use a prohibited backhaul RACH occasion
component 935. The prohibited backhaul RACH occasion component 935
may receive the configuration signaling indicating a prohibited
backhaul RACH occasion of the set of different backhaul RACH
occasions.
[0154] When the device is acting as an MT, the communications
manager 905 may include and use a backhaul RACH transmission power
component 940. The backhaul RACH transmission power component 940
may select a transmission power for the backhaul random access
message based on a first parameter for received power, the first
parameter for received power exceeding a second parameter for
received power for an access random access message configured for
transmission by a UE. In some examples, the backhaul RACH
transmission power component 940 may transmit the backhaul random
access message in accordance with the selected transmission
power.
[0155] When the device is acting as a DU or CU (e.g., a first
access node in an IAB), the communications manager 905 may include
and use a RACH configuration component 910. The RACH configuration
component 910 may transmit, to an MT (e.g., a second access node,
connecting device, etc.), first configuration signaling indicating
a shared RACH resource and a backhaul RACH preamble format.
Additionally, the RACH configuration component 910 may transmit, to
a UE, second configuration signaling indicating the shared RACH
resource and an access RACH preamble format, the backhaul RACH
preamble format differing from the access RACH preamble format. In
some examples, the RACH configuration component 910 may transmit
the first configuration signaling indicating a number of symbols in
the backhaul RACH preamble format, the number of symbols being
fewer than a number of symbols in the access RACH preamble format.
Additionally or alternatively, the RACH configuration component 910
may transmit the first configuration signaling indicating a number
of symbols in the backhaul RACH preamble format, the number of
symbols being the same as a number of symbols in the access RACH
preamble format. In some cases, the shared RACH resource may be a
time and frequency resource useable for both access and backhaul
communications.
[0156] When the device is acting as a DU or CU, the communications
manager 905 may include and use a RACH monitoring component 945.
The RACH monitoring component 945 may monitor the shared RACH
resource for at least one of a first random access message in
accordance with the backhaul RACH preamble format or a second
random access message in accordance with the access RACH preamble
format.
[0157] When the device is acting as a DU or CU, the communications
manager 905 may include and use a backhaul RACH communicator 915.
The backhaul RACH communicator 915 may receive, from the MT, the
first random access message in accordance with the backhaul RACH
preamble format within the shared RACH resource.
[0158] When the device is acting as a DU or CU, the communications
manager 905 may include and use a backhaul link establishment
component 920. The backhaul link establishment component 920 may
establish a backhaul link with the MT based on the first random
access message.
[0159] When the device is acting as a DU or CU, the communications
manager 905 may include and use an access RACH component 950. The
access RACH component 950 may receive, from the UE, the second
random access message in accordance with the access RACH preamble
format within the shared RACH resource. In some examples, the
access RACH component 950 may establish an access link with the UE
based on the second random access message. Additionally, the access
RACH component 950 may detect, using an energy detection algorithm,
a signal that includes the first random access message in
accordance with the backhaul RACH preamble format within the shared
RACH resource. In some cases, the access RACH component 950 may
generate a modified signal by removing the first random access
message from the signal and may process the modified signal to
obtain the second random access message.
[0160] When the device is acting as a DU or CU, the communications
manager 905 may include and use a backhaul RACH transmission power
component 940. The backhaul RACH transmission power component 940
may transmit the first configuration signaling indicating a first
parameter for received power for the first random access message,
the first parameter for received power exceeding a second parameter
for received power for the second random access message configured
for transmission by the UE.
[0161] When the device is acting as a DU or CU, the communications
manager 905 may include and use a backhaul RACH occasion component
925. The backhaul RACH occasion component 925 may transmit the
first configuration signaling indicating a set of different
backhaul RACH occasions within the shared RACH resource.
Additionally, the backhaul RACH occasion component 925 may receive,
from the MT, the first random access message in accordance with the
backhaul RACH preamble format within a first backhaul RACH occasion
of the set of different backhaul RACH occasions and may identify
information based on the first backhaul RACH occasion. In some
cases, the backhaul RACH occasion component 925 may identify a
number of downstream access nodes based on the first backhaul RACH
occasion.
[0162] When the device is acting as a DU or CU, the communications
manager 905 may include and use a prohibited backhaul RACH occasion
component 935. The prohibited backhaul RACH occasion component 935
may transmit the first configuration signaling indicating a
prohibited backhaul RACH occasion of the set of different backhaul
RACH occasions.
[0163] FIG. 10 shows a diagram of a system 1000 including a device
1005 that supports a modified backhaul RACH in accordance with one
or more aspects of the present disclosure. The device 1005 may be
an example of or include the components of device 705, device 805,
a base station 105, a network device 105, an access node 105, a
connecting device (e.g., an MT), or a serving device (e.g., a
mobile parent, a DU, a CU, etc.) as described herein. The device
1005 may include components for bi-directional voice and data
communications including components for transmitting and receiving
communications, including a communications manager 1010, a network
communications manager 1015, a transceiver 1020, an antenna 1025,
memory 1030, a processor 1040, and an inter-station communications
manager 1045. These components may be in electronic communication
via one or more buses (e.g., bus 1050).
[0164] When device 1005 is acting as an MT (e.g., a first access
node in an IAB), the communications manager 1010 may receive, from
a DU or CU (e.g., a second access node), configuration signaling
indicating a shared RACH resource and a backhaul RACH preamble
format, the backhaul RACH preamble format differing from an access
RACH preamble format. Accordingly, the communications manager 1010
may transmit, to the DU or CU, a backhaul random access message in
accordance with the backhaul RACH preamble format within the shared
RACH resource. In some cases, the communications manager 1010 may
establish a backhaul link with the DU or CU based on the backhaul
random access message.
[0165] Additionally or alternatively, when device 1005 is acting as
a DU or CU (e.g., a first access node in an IAB), the
communications manager 1010 may transmit, to an MT (e.g., a second
access node), first configuration signaling indicating a shared
RACH resource and a backhaul RACH preamble format. Additionally,
the communications manager 1010 may transmit, to a UE, second
configuration signaling indicating the shared RACH resource and an
access RACH preamble format, the backhaul RACH preamble format
differing from the access RACH preamble format. Accordingly, the
communications manager 1010 may monitor the shared RACH resource
for at least one of a first random access message in accordance
with the backhaul RACH preamble format or a second random access
message in accordance with the access RACH preamble format.
[0166] The network communications manager 1015 may manage
communications with the core network (e.g., via one or more wired
backhaul links). For example, the network communications manager
1015 may manage the transfer of data communications for client
devices, such as one or more UEs 115.
[0167] The transceiver 1020 may communicate bi-directionally, via
one or more antennas, wired, or wireless links as described above.
For example, the transceiver 1020 may represent a wireless
transceiver and may communicate bi-directionally with another
wireless transceiver. The transceiver 1020 may also include a modem
to modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
[0168] In some cases, the wireless device may include a single
antenna 1025. However, in some cases the device may have more than
one antenna 1025, which may be capable of concurrently transmitting
or receiving multiple wireless transmissions.
[0169] The memory 1030 may include random-access memory (RAM),
read-only memory (ROM), or a combination thereof. The memory 1030
may store computer-readable code 1035 including instructions that,
when executed by a processor (e.g., the processor 1040) cause the
device to perform various functions described herein. In some
cases, the memory 1030 may contain, among other things, a basic I/O
system (BIOS) which may control basic hardware or software
operation such as the interaction with peripheral components or
devices.
[0170] The processor 1040 may include an intelligent hardware
device, (e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a PLD, a discrete gate or
transistor logic component, a discrete hardware component, or any
combination thereof). In some cases, the processor 1040 may be
configured to operate a memory array using a memory controller. In
some cases, a memory controller may be integrated into processor
1040. The processor 1040 may be configured to execute
computer-readable instructions stored in a memory (e.g., the memory
1030) to cause the device 1005 to perform various functions (e.g.,
functions or tasks supporting modified backhaul RACH).
[0171] The inter-station communications manager 1045 may manage
communications with other base station 105 and may include a
controller or scheduler for controlling communications with UEs 115
in cooperation with other base stations 105. For example, the
inter-station communications manager 1045 may coordinate scheduling
for transmissions to UEs 115 for various interference mitigation
techniques such as beamforming or joint transmission. In some
examples, the inter-station communications manager 1045 may provide
an X2 interface within an LTE/LTE-A wireless communication network
technology to provide communication between base stations 105.
[0172] The code 1035 may include instructions to implement aspects
of the present disclosure, including instructions to support
wireless communications. The code 1035 may be stored in a
non-transitory computer-readable medium such as system memory or
other type of memory. In some cases, the code 1035 may not be
directly executable by the processor 1040 but may cause a computer
(e.g., when compiled and executed) to perform functions described
herein.
[0173] FIG. 11 shows a flowchart illustrating a method 1100 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1100
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1100 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of an MT (e.g., a first access node
in an TAB). In some examples, a base station may execute a set of
instructions to control the functional elements of the base station
to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0174] At 1105, the MT may receive, from a DU or CU (e.g., second
access node), configuration signaling indicating a shared RACH
resource and a backhaul RACH preamble format, the backhaul RACH
preamble format differing from an access RACH preamble format. The
operations of 1105 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1105 may be performed by a RACH configuration component as
described with reference to FIGS. 7 through 10.
[0175] At 1110, the MT may transmit, to the DU or CU, a backhaul
random access message in accordance with the backhaul RACH preamble
format within the shared RACH resource. The operations of 1110 may
be performed according to the methods described herein. In some
examples, aspects of the operations of 1110 may be performed by a
backhaul RACH communicator as described with reference to FIGS. 7
through 10.
[0176] At 1115, the MT may establish a backhaul link with the DU or
CU based on the backhaul random access message. The operations of
1115 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1115 may be performed
by a backhaul link establishment component as described with
reference to FIGS. 7 through 10.
[0177] FIG. 12 shows a flowchart illustrating a method 1200 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1200
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1200 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of an MT (e.g., a first access node
in an TAB). In some examples, a base station may execute a set of
instructions to control the functional elements of the base station
to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0178] At 1205, the MT may receive, from a DU or CU (e.g., a second
access node), configuration signaling indicating a shared RACH
resource and a backhaul RACH preamble format, the backhaul RACH
preamble format differing from an access RACH preamble format. The
operations of 1205 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1205 may be performed by a RACH configuration component as
described with reference to FIGS. 7 through 10.
[0179] At 1210, the MT may receive the configuration signaling
indicating a set of different backhaul RACH occasions within the
shared RACH resource. The operations of 1210 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1210 may be performed by a backhaul
RACH occasion component as described with reference to FIGS. 7
through 10.
[0180] At 1215, the MT may select a first backhaul RACH occasion
from the set of different backhaul RACH occasions, where the
backhaul random access message is transmitted within the first
backhaul RACH occasion. The operations of 1215 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1215 may be performed by a backhaul
RACH occasion selector as described with reference to FIGS. 7
through 10.
[0181] At 1220, the MT may transmit, to the DU or CU, a backhaul
random access message in accordance with the backhaul RACH preamble
format within the shared RACH resource. The operations of 1220 may
be performed according to the methods described herein. In some
examples, aspects of the operations of 1220 may be performed by a
backhaul RACH communicator as described with reference to FIGS. 7
through 10.
[0182] At 1225, the MT may establish a backhaul link with the DU or
CU based on the backhaul random access message. The operations of
1225 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1225 may be performed
by a backhaul link establishment component as described with
reference to FIGS. 7 through 10.
[0183] FIG. 13 shows a flowchart illustrating a method 1300 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1300
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1300 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of an MT (e.g., a first access node
in an TAB). In some examples, a base station may execute a set of
instructions to control the functional elements of the base station
to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0184] At 1305, the MT may receive, from a DU or CU (e.g., a second
access node), configuration signaling indicating a shared RACH
resource and a backhaul RACH preamble format, the backhaul RACH
preamble format differing from an access RACH preamble format. The
operations of 1305 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1305 may be performed by a RACH configuration component as
described with reference to FIGS. 7 through 10.
[0185] At 1310, the MT may receive the configuration signaling
indicating a number of symbols in the backhaul RACH preamble
format, the number of symbols being fewer than a number of symbols
in the access RACH preamble format. The operations of 1310 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 1310 may be performed by a
RACH configuration component as described with reference to FIGS. 7
through 10.
[0186] At 1315, the MT may transmit, to the DU or CU, a backhaul
random access message in accordance with the backhaul RACH preamble
format within the shared RACH resource. The operations of 1315 may
be performed according to the methods described herein. In some
examples, aspects of the operations of 1315 may be performed by a
backhaul RACH communicator as described with reference to FIGS. 7
through 10.
[0187] At 1320, the MT may establish a backhaul link with the DU or
CU based on the backhaul random access message. The operations of
1320 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1320 may be performed
by a backhaul link establishment component as described with
reference to FIGS. 7 through 10.
[0188] FIG. 14 shows a flowchart illustrating a method 1400 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1400
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1400 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of a DU or CU (e.g., a first access
node in an IAB). In some examples, a base station may execute a set
of instructions to control the functional elements of the base
station to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0189] At 1405, the DU or CU may transmit, to an MT (e.g., a second
access node), first configuration signaling indicating a shared
RACH resource and a backhaul RACH preamble format. The operations
of 1405 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1405 may be
performed by a RACH configuration component as described with
reference to FIGS. 7 through 10.
[0190] At 1410, the DU or CU may transmit, to a UE, second
configuration signaling indicating the shared RACH resource and an
access RACH preamble format, the backhaul RACH preamble format
differing from the access RACH preamble format. The operations of
1410 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1410 may be performed
by a RACH configuration component as described with reference to
FIGS. 7 through 10.
[0191] At 1415, the DU or CU may monitor the shared RACH resource
for at least one of a first random access message in accordance
with the backhaul RACH preamble format or a second random access
message in accordance with the access RACH preamble format. The
operations of 1415 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1415 may be performed by a RACH monitoring component as described
with reference to FIGS. 7 through 10.
[0192] FIG. 15 shows a flowchart illustrating a method 1500 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1500
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1500 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of a DU or CU (e.g., a first access
node in an IAB). In some examples, a base station may execute a set
of instructions to control the functional elements of the base
station to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0193] At 1505, the DU or CU may transmit, to an MT (e.g., a second
access node), first configuration signaling indicating a shared
RACH resource and a backhaul RACH preamble format. The operations
of 1505 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1505 may be
performed by a RACH configuration component as described with
reference to FIGS. 7 through 10.
[0194] At 1510, the DU or CU may transmit the first configuration
signaling indicating a number of symbols in the backhaul RACH
preamble format, the number of symbols being fewer than a number of
symbols in an access RACH preamble format. The operations of 1510
may be performed according to the methods described herein. In some
examples, aspects of the operations of 1510 may be performed by a
RACH configuration component as described with reference to FIGS. 7
through 10.
[0195] At 1515, the DU or CU may transmit, to a UE, second
configuration signaling indicating the shared RACH resource and the
access RACH preamble format, the backhaul RACH preamble format
differing from the access RACH preamble format. The operations of
1515 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1515 may be performed
by a RACH configuration component as described with reference to
FIGS. 7 through 10.
[0196] At 1520, the DU or CU may monitor the shared RACH resource
for at least one of a first random access message in accordance
with the backhaul RACH preamble format or a second random access
message in accordance with the access RACH preamble format. The
operations of 1520 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1520 may be performed by a RACH monitoring component as described
with reference to FIGS. 7 through 10.
[0197] FIG. 16 shows a flowchart illustrating a method 1600 that
supports a modified backhaul RACH in accordance with one or more
aspects of the present disclosure. The operations of method 1600
may be implemented by a base station 105, a network device 105, an
access node 105, a connecting device (e.g., an MT), a serving
device (e.g., a mobile parent, a DU, a CU, etc.) or associated
components as described herein. For example, the operations of
method 1600 may be performed by a communications manager as
described with reference to FIGS. 7 through 10, where the
communications manager is part of a DU or CU (e.g., a first access
node in an IAB). In some examples, a base station may execute a set
of instructions to control the functional elements of the base
station to perform the functions described below. Additionally or
alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0198] At 1605, the DU or CU may transmit, to an MT (e.g., a second
access node), first configuration signaling indicating a shared
RACH resource and a backhaul RACH preamble format. The operations
of 1605 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1605 may be
performed by a RACH configuration component as described with
reference to FIGS. 7 through 10.
[0199] At 1610, the DU or CU may transmit the first configuration
signaling indicating a set of different backhaul RACH occasions
within the shared RACH resource. The operations of 1610 may be
performed according to the methods described herein. In some
examples, aspects of the operations of 1610 may be performed by a
backhaul RACH occasion component as described with reference to
FIGS. 7 through 10.
[0200] At 1615, the DU or CU may transmit, to a UE, second
configuration signaling indicating the shared RACH resource and an
access RACH preamble format, the backhaul RACH preamble format
differing from the access RACH preamble format. The operations of
1615 may be performed according to the methods described herein. In
some examples, aspects of the operations of 1615 may be performed
by a RACH configuration component as described with reference to
FIGS. 7 through 10.
[0201] At 1620, the DU or CU may monitor the shared RACH resource
for at least one of a first random access message in accordance
with the backhaul RACH preamble format or a second random access
message in accordance with the access RACH preamble format. The
operations of 1620 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1620 may be performed by a RACH monitoring component as described
with reference to FIGS. 7 through 10.
[0202] It should be noted that the methods described herein
describe possible implementations, and that the operations may be
rearranged or otherwise modified and that other implementations are
possible. Further, aspects from two or more of the methods may be
combined.
[0203] Techniques described herein may be used for various wireless
communications systems such as CDMA, TDMA, FDMA, OFDMA, single
carrier frequency division multiple access (SC-FDMA), and other
systems. A CDMA system may implement a radio technology such as
CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000
covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may
be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856)
is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data
(HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants
of CDMA. A TDMA system may implement a radio technology such as
Global System for Mobile Communications (GSM).
[0204] An OFDMA system may implement a radio technology such as
Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of
Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunications System (UMTS). LTE,
LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA,
E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in
documents from the organization named "3rd Generation Partnership
Project" (3GPP). CDMA2000 and UMB are described in documents from
an organization named "3rd Generation Partnership Project 2"
(3GPP2). The techniques described herein may be used for the
systems and radio technologies mentioned herein as well as other
systems and radio technologies. While aspects of an LTE, LTE-A,
LTE-A Pro, or NR system may be described for purposes of example,
and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of
the description, the techniques described herein are applicable
beyond LTE, LTE-A, LTE-A Pro, or NR applications.
[0205] A macro cell generally covers a relatively large geographic
area (e.g., several kilometers in radius) and may allow
unrestricted access by UEs with service subscriptions with the
network provider. A small cell may be associated with a
lower-powered base station, as compared with a macro cell, and a
small cell may operate in the same or different (e.g., licensed,
unlicensed, etc.) frequency bands as macro cells. Small cells may
include pico cells, femto cells, and micro cells according to
various examples. A pico cell, for example, may cover a small
geographic area and may allow unrestricted access by UEs with
service subscriptions with the network provider. A femto cell may
also cover a small geographic area (e.g., a home) and may provide
restricted access by UEs having an association with the femto cell
(e.g., UEs in a closed subscriber group (CSG), UEs for users in the
home, and the like). An eNB for a macro cell may be referred to as
a macro eNB. An eNB for a small cell may be referred to as a small
cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may
support one or multiple (e.g., two, three, four, and the like)
cells, and may also support communications using one or multiple
component carriers. A gNB for a macro cell may be referred to as a
macro gNB. A gNB for a small cell may be referred to as a small
cell gNB, a pico gNB, a femto gNB, or a home gNB. A gNB may support
one or multiple (e.g., two, three, four, and the like) cells (e.g.,
component carriers). A UE may be able to communicate with various
types of base stations and network equipment including macro eNBs,
small cell eNBs, relay base stations, and the like.
[0206] The wireless communications systems described herein may
support synchronous or asynchronous operation. For synchronous
operation, the base stations may have similar frame timing, and
transmissions from different base stations may be approximately
aligned in time. For asynchronous operation, the base stations may
have different frame timing, and transmissions from different base
stations may not be aligned in time. The techniques described
herein may be used for either synchronous or asynchronous
operations.
[0207] Information and signals described herein may be represented
using any of a variety of different technologies and techniques.
For example, data, instructions, commands, information, signals,
bits, symbols, and chips that may be referenced throughout the
description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields
or particles, or any combination thereof.
[0208] The various illustrative blocks and modules described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a DSP, an ASIC, an
FPGA, or other PLD, discrete gate or transistor logic, discrete
hardware components, or any combination thereof designed to perform
the functions described herein. A general-purpose processor may be
a microprocessor, but in the alternative, the processor may be any
conventional processor, controller, microcontroller, or state
machine. A processor may also be implemented as a combination of
computing devices (e.g., a combination of a DSP and a
microprocessor, multiple microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration).
[0209] The functions described herein may be implemented in
hardware, software executed by a processor, firmware, or any
combination thereof. If implemented in software executed by a
processor, the functions may be stored on or transmitted over as
one or more instructions or code on a computer-readable medium.
Other examples and implementations are within the scope of the
disclosure and appended claims. For example, due to the nature of
software, functions described herein can be implemented using
software executed by a processor, hardware, firmware, hardwiring,
or combinations of any of these. Features implementing functions
may also be physically located at various positions, including
being distributed such that portions of functions are implemented
at different physical locations.
[0210] Computer-readable media includes both non-transitory
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A non-transitory storage medium may be any available
medium that can be accessed by a general purpose or special purpose
computer. By way of example, and not limitation, non-transitory
computer-readable media may include RAM, ROM, electrically erasable
programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other non-transitory medium that can be
used to carry or store desired program code means in the form of
instructions or data structures and that can be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, include CD, laser disc, optical disc, digital
versatile disc (DVD), floppy disk and Blu-ray disc where disks
usually reproduce data magnetically, while discs reproduce data
optically with lasers. Combinations of the above are also included
within the scope of computer-readable media.
[0211] As used herein, including in the claims, "or" as used in a
list of items (e.g., a list of items prefaced by a phrase such as
"at least one of" or "one or more of") indicates an inclusive list
such that, for example, a list of at least one of A, B, or C means
A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also,
as used herein, the phrase "based on" shall not be construed as a
reference to a closed set of conditions. For example, an exemplary
operation that is described as "based on condition A" may be based
on both a condition A and a condition B without departing from the
scope of the present disclosure. In other words, as used herein,
the phrase "based on" shall be construed in the same manner as the
phrase "based at least in part on."
[0212] In the appended figures, similar components or features may
have the same reference label. Further, various components of the
same type may be distinguished by following the reference label by
a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label, or other subsequent
reference label.
[0213] The description set forth herein, in connection with the
appended drawings, describes example configurations and does not
represent all the examples that may be implemented or that are
within the scope of the claims. The term "exemplary" used herein
means "serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, well-known structures and devices are shown in block
diagram form in order to avoid obscuring the concepts of the
described examples.
[0214] The description herein is provided to enable a person
skilled in the art to make or use the disclosure. Various
modifications to the disclosure will be readily apparent to those
skilled in the art, and the generic principles defined herein may
be applied to other variations without departing from the scope of
the disclosure. Thus, the disclosure is not limited to the examples
and designs described herein, but is to be accorded the broadest
scope consistent with the principles and novel features disclosed
herein.
* * * * *