U.S. patent application number 15/647912 was filed with the patent office on 2019-01-17 for system and method for backhaul and access in beamformed communications systems.
This patent application is currently assigned to Futurewei Technologies, Inc.. The applicant listed for this patent is Futurewei Technologies, Inc.. Invention is credited to Richard Stirling-Gallacher, Lili Zhang, Hongcheng Zhuang.
Application Number | 20190021084 15/647912 |
Document ID | / |
Family ID | 64999412 |
Filed Date | 2019-01-17 |
View All Diagrams
United States Patent
Application |
20190021084 |
Kind Code |
A1 |
Stirling-Gallacher; Richard ;
et al. |
January 17, 2019 |
System And Method For Backhaul and Access In Beamformed
Communications Systems
Abstract
A method for performing beamformed backhaul communications
includes determining first formats of subframes supporting access
communications between the first TRP and user equipments (UEs)
served by the first TRP, determining a subset of the subframes
supporting access communications, the subset of the subframes
supports backhaul communications between the first TRP and a second
TRP, and communicating with a UE over an access link in accordance
with the subset of subframes.
Inventors: |
Stirling-Gallacher; Richard;
(San Diego, CA) ; Zhuang; Hongcheng; (Shenzhen,
CN) ; Zhang; Lili; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Futurewei Technologies, Inc. |
Plano |
TX |
US |
|
|
Assignee: |
Futurewei Technologies,
Inc.
Plano
TX
Futurewei Technologies, Inc.
Plano
TX
|
Family ID: |
64999412 |
Appl. No.: |
15/647912 |
Filed: |
July 12, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/0446 20130101;
H04W 72/046 20130101; H04W 72/048 20130101; H04W 72/082 20130101;
H04W 72/0453 20130101; H04W 16/28 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 16/28 20060101 H04W016/28; H04W 72/08 20060101
H04W072/08 |
Claims
1. A method for performing beamformed backhaul communications, the
method comprising: determining, by a first transmit-receive point
(TRP), first formats of subframes supporting access communications
between the first TRP and user equipments (UEs) served by the first
TRP; determining, by the first TRP, a subset of the subframes
supporting access communications, the subset of the subframes
supports backhaul communications between the first TRP and a second
TRP; and communicating, by the first TRP, with a UE over an access
link in accordance with the subset of the subframes.
2. The method of claim 1, further comprising communicating, by the
first TRP, with the second TRP in accordance with the first
formats.
3. The method of claim 1, further comprising: providing, by the
first TRP, a first TRP capability to a network entity determining
formats of subframes supporting access communications and formats
of subframes supporting backhaul communications.
4. The method of claim 1, further comprising: providing to a
network entity determining formats of subframes supporting access
communications and formats of subframes supporting backhaul
communications, by the first TRP, first requested formats of
subframes supporting access communications between the first TRP
and the UEs served by the first TRP.
5. The method of claim 1, further comprising: receiving, by the
first TRP, a second TRP capability of the second TRP; and providing
to a network entity determining formats of subframes supporting
access communications and formats of subframes supporting backhaul
communications, by the first TRP, the second TRP capability of the
second TRP.
6. The method of claim 5, further comprising: receiving, by the
first TRP, second requested formats of subframes supporting access
communications between the second TRP and UEs served by the second
TRP; and providing, by the first TRP, the second requested formats
to the network entity.
7. The method of claim 1, wherein determining the first formats and
the subset of the subframes comprises one of retrieving the first
formats and the subset of the subframes from a memory, receiving
the first formats and the subset of the subframes from a network
entity determining formats of subframes supporting access
communications and formats of subframes supporting backhaul
communications, or receiving the first formats and the subset of
the subframes from a third TRP.
8. The method of claim 1, wherein each format in the first formats
indicates an allocation of one of a first type of subframe of a
radio frame to convey uplink access data, or a second type of
subframe of the radio frame to convey downlink access data.
9. The method of claim 8, wherein the subset of the subframes
indicates at least one subframe of the first type or the second
type of subframes to convey backhaul data.
10. A method for supporting beamformed backhaul communications, the
method comprising: selecting, by a network entity, first formats of
first subframes supporting access communications at a first
transmit-receive point (TRP) in accordance with TRP capabilities of
the first TRP; selecting, by the network entity, second formats of
second subframes supporting access communications at a second TRP
in accordance with TRP capabilities of the second TRP; selecting,
by the network entity, a subset of the first formats and the second
formats for supporting backhaul communications between the first
TRP and the second TRP, wherein the subset of the first formats and
the second formats is selected in accordance with the TRP
capabilities of the first TRP and the second TRP; and signaling, by
the network entity, indications of the first formats of the first
subframes, the second formats of the second subframes, and the
subset of the first formats and the second formats to the first TRP
and the second TRP.
11. The method of claim 10, wherein the TRP capabilities comprises
at least one of self-interference cancellation capability, or
integrated access and backhaul (JAB) capability.
12. The method of claim 10, wherein selecting the subset of the
first formats and the second formats is also in accordance with at
least one of first requested formats of subframes supporting access
communications of the first TRP or second requested formats of
subframes supporting access communications of the second TRP.
13. The method of claim 10, wherein selecting the first formats is
also in accordance with first requested formats of subframes
supporting access communications of the first TRP, and wherein
selecting the second formats is also in accordance with second
requested formats of subframes supporting access communications of
the second TRP.
14. The method of claim 10, wherein the first and second TRPs are
self-interference cancellation capable within a single sector, and
wherein the subset of the first formats and the second formats
comprises all formats of the first and second formats.
15. The method of claim 10, wherein one of the first or second TRPs
is self-interference cancellation incapable within a single sector,
and wherein the subset of the first formats and the second formats
comprises formats that correspond to the one of the first or second
TRPs that is self-interference cancellation incapable.
16. The method of claim 10, wherein the first and second TRPs are
self-interference cancellation incapable within a single sector,
and wherein the subset of the first formats and the second formats
comprises conflicting formats of the first and second formats.
17. The method of claim 10, wherein the TRP capability further
comprises access and backhaul multiplexing in at least one of a
time domain, a frequency domain, or a space domain.
18. A first transmit-receive point (TRP) comprising: one or more
processors; and a computer readable storage medium storing
programming for execution by the one or more processors, the
programming including instructions to configure the first TRP to:
determine first formats of subframes supporting access
communications between the first TRP and user equipments (UEs)
served by the first TRP, determine a subset of the subframes
supporting access communications, the subset of the subframes
supports backhaul communications between the first TRP and a second
TRP, and communicate with a UE over an access link in accordance
with the subset of the subframes.
19. The first TRP of claim 18, wherein the programming includes
instructions to configure the first TRP to communicate with the
second TRP in accordance with the first formats.
20. The first TRP of claim 18, wherein the programming includes
instructions to configure the first TRP to provide a first TRP
capability to a network entity determining formats of subframes
supporting access communications and formats of subframes
supporting backhaul communications.
21. The first TRP of claim 18, wherein the programming includes
instructions to configure the first TRP to provide to a network
entity determining formats of subframes supporting access
communications and formats of subframes supporting backhaul
communications, first requested formats of subframes supporting
access communications between the first TRP and the UEs served by
the first TRP.
22. The first TRP of claim 18, wherein the programming includes
instructions to configure the first TRP to receive a second TRP
capability of the second TRP, and provide to a network entity
determining formats of subframes supporting access communications
and formats of subframes supporting backhaul communications, the
second TRP capability of the second TRP.
23. The first TRP of claim 22, wherein the programming includes
instructions to configure the first TRP to receive second requested
formats of subframes supporting access communications between the
second TRP and UEs served by the second TRP, and provide the second
requested formats to the network entity.
24. The first TRP of claim 18, wherein the programming includes
instructions to configure the first TRP to one of retrieve the
first formats and the subset of the subframes from a memory,
receive the first formats and the subset of the subframes from a
network entity determining formats of subframes supporting access
communications and formats of subframes supporting backhaul
communications, or receive the first formats and the subset of the
subframes from a third TRP.
25. A network entity comprising: one or more processors; and a
computer readable storage medium storing programming for execution
by the one or more processors, the programming including
instructions to configure the network entity to: select first
formats of first subframes supporting access communications at a
first transmit-receive point (TRP) in accordance with TRP
capabilities of the first TRP, select second formats of second
subframes supporting access communications at a second TRP in
accordance with TRP capabilities of the second TRP, select a subset
of the first formats and the second formats for supporting backhaul
communications between the first TRP and the second TRP, wherein
the subset of the first formats and the second formats is selected
in accordance with the TRP capabilities of the first TRP and the
second TRP, and signal indications of the first formats of the
first subframes, the second formats of the second subframes, and
the subset of the first formats and the second formats to the first
TRP and the second TRP.
26. The network entity of claim 25, wherein the first and second
TRPs are self-interference cancellation capable within a single
sector, and wherein the subset of the first formats and the second
formats comprises all formats of the first and second formats.
27. The network entity of claim 25, wherein one of the first or
second TRPs is self-interference cancellation incapable within a
single sector, and wherein the subset of the first formats and the
second formats comprises formats that correspond to the one of the
first or second TRPs that is self-interference cancellation
incapable.
28. The network entity of claim 25, wherein the first and second
TRPs are self-interference cancellation incapable within a single
sector, and wherein the subset of the first formats and the second
formats comprises conflicting formats of the first and second
formats.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a system and
method for digital communications, and, in particular embodiments,
to a system and method for backhaul and access in beamformed
communications systems.
BACKGROUND
[0002] In communications systems, the term backhaul or backhaul
links refers to links of a communications system that provide
interconnectivity between core network entities, such as access
nodes, communications controllers, mobility entities, gateways,
service providers, and so on. In other words, the backhaul links do
not include links that provide connectivity to the user equipment
(UE). A fronthaul is similar to a backhaul and includes links
between communications controllers to remote radio heads (RRHs). On
the other hand, the term access or access links refers to links of
a communications system that provides interconnectivity between UEs
and access nodes. More simply, access refers to links that connect
the UEs to the core network entities of the communications
system.
[0003] Future wireless communications systems are operating at ever
higher carrier frequencies in a quest to find greater bandwidth and
less interference. These wireless communications systems may
operate at frequencies of 6 GHz and above, such as millimeter
(mmWave) frequencies. In order to fully utilize the greater
bandwidth available in the wireless communications systems,
transmission-reception points (TRPs) may require more bandwidth and
less latency than what is afforded in existing backhaul and/or
fronthaul links. Furthermore the density of the TRPs is likely to
be much higher than current deployments and the cost of laying
wireline high capacity backhaul connections to all of these TRPs
can be prohibitive. Additionally, in certain situations some TRPs
may be temporal in nature or mobile and may not be able to support
a wireline connection.
[0004] Therefore, there is a need for systems and methods that
support backhaul and access in beamformed communications
systems.
SUMMARY
[0005] Example embodiments provide a system and method for backhaul
and access in beamformed communications systems.
[0006] In accordance with an example embodiment, a method for
performing beamformed backhaul communications is provided. The
method includes determining, by a first transmit-receive point
(TRP), first formats of subframes supporting access communications
between the first TRP and user equipments (UEs) served by the first
TRP, determining, by the first TRP, a subset of the subframes
supporting access communications, the subset of the subframes
supports backhaul communications between the first TRP and a second
TRP, and communicating, by the first TRP, with a UE over an access
link in accordance with the subset of the subframes.
[0007] Optionally, in any of the preceding embodiments, the method
further comprises communicating, by the first TRP, with the second
TRP in accordance with the first formats.
[0008] Optionally, in any of the preceding embodiments, the method
further comprises providing, by the first TRP, a first TRP
capability to a network entity determining formats of subframes
supporting access communications and formats of subframes
supporting backhaul communications.
[0009] Optionally, in any of the preceding embodiments, the method
further comprises providing to a network entity determining formats
of subframes supporting access communications and formats of
subframes supporting backhaul communications, by the first TRP,
first requested formats of subframes supporting access
communications between the first TRP and the UEs served by the
first TRP.
[0010] Optionally, in any of the preceding embodiments, the method
further comprises receiving, by the first TRP, a second TRP
capability of the second TRP, and providing to a network entity
determining formats of subframes supporting access communications
and formats of subframes supporting backhaul communications, by the
first TRP, the second TRP capability of the second TRP.
[0011] Optionally, in any of the preceding embodiments, the method
further comprises receiving, by the first TRP, second requested
formats of subframes supporting access communications between the
second TRP and UEs served by the second TRP, and providing, by the
first TRP, the second requested formats to the network entity.
[0012] Optionally, in any of the preceding embodiments, wherein
determining the first formats and the subset of the subframes
includes one of retrieving the first formats and the subset of the
subframes from a memory, receiving the first formats and the subset
of the subframes from a network entity determining formats of
subframes supporting access communications and formats of subframes
supporting backhaul communications, or receiving the first formats
and the subset of the subframes from a third TRP.
[0013] Optionally, in any of the preceding embodiments, wherein
each format in the first formats indicates an allocation of one of
a first type of subframe of a radio frame to convey uplink access
data, or a second type of subframe of the radio frame to convey
downlink access data.
[0014] Optionally, in any of the preceding embodiments, wherein the
subset of the subframes indicates at least one subframe of the
first type or the second type of subframes to convey backhaul
data.
[0015] In accordance with an example embodiment, a method for
supporting beamformed backhaul communications is provided. The
method includes selecting, by a network entity, first formats of
first subframes supporting access communications at a first TRP in
accordance with TRP capabilities of the first TRP, selecting, by
the network entity, second formats of second subframes supporting
access communications at a second TRP in accordance with TRP
capabilities of the second TRP, selecting, by the network entity, a
subset of the first formats and the second formats for supporting
backhaul communications between the first TRP and the second TRP,
wherein the subset of the first formats and the second formats is
selected in accordance with the TRP capabilities of the first TRP
and the second TRP, and signaling, by the network entity,
indications of the first formats of the first subframes, the second
formats of the second subframes, and the subset of the first
formats and the second formats to the first TRP and the second
TRP.
[0016] Optionally, in any of the preceding embodiments, wherein the
TRP capabilities comprises at least one of self-interference
cancellation capability, or integrated access and backhaul (IAB)
capability.
[0017] Optionally, in any of the preceding embodiments, wherein
selecting the subset of the first formats and the second formats is
also in accordance with at least one of first requested formats of
subframes supporting access communications of the first TRP or
second requested formats of subframes supporting access
communications of the second TRP.
[0018] Optionally, in any of the preceding embodiments, wherein
selecting the first formats is also in accordance with first
requested formats of subframes supporting access communications of
the first TRP, and wherein selecting the second formats is also in
accordance with second requested formats of subframes supporting
access communications of the second TRP.
[0019] Optionally, in any of the preceding embodiments, wherein the
first and second TRPs are self-interference cancellation capable
within a single sector, and wherein the subset of the first formats
and the second formats comprises all formats of the first and
second formats.
[0020] Optionally, in any of the preceding embodiments, wherein one
of the first or second TRPs is self-interference cancellation
incapable within a single sector, and wherein the subset of the
first formats and the second formats comprises formats that
correspond to the one of the first or second TRPs that is
self-interference cancellation incapable.
[0021] Optionally, in any of the preceding embodiments, wherein the
first and second TRPs are self-interference cancellation incapable
within a single sector, and wherein the subset of the first formats
and the second formats comprises conflicting formats of the first
and second formats.
[0022] Optionally, in any of the preceding embodiments, wherein the
TRP capability further comprises access and backhaul multiplexing
in at least one of a time domain, a frequency domain, or a space
domain.
[0023] In accordance with an example embodiment, first TRP is
provided. The first TRP includes one or more processors, and a
computer readable storage medium storing programming for execution
by the one or more processors. The programming including
instructions to configure the first TRP to determine first formats
of subframes supporting access communications between the first TRP
and UEs served by the first TRP, determine a subset of the
subframes supporting access communications, the subset of the
subframes supports backhaul communications between the first TRP
and a second TRP, and communicate with a UE over an access link in
accordance with the subset of the subframes.
[0024] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to
communicate with the second TRP in accordance with the first
formats.
[0025] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to
provide a first TRP capability to a network entity determining
formats of subframes supporting access communications and formats
of subframes supporting backhaul communications.
[0026] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to
provide to a network entity determining formats of subframes
supporting access communications and formats of subframes
supporting backhaul communications, first requested formats of
subframes supporting access communications between the first TRP
and the UEs served by the first TRP.
[0027] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to
receive a second TRP capability of the second TRP, and provide to a
network entity determining formats of subframes supporting access
communications and formats of subframes supporting backhaul
communications, the second TRP capability of the second TRP.
[0028] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to
receive second requested formats of subframes supporting access
communications between the second TRP and UEs served by the second
TRP, and provide the second requested formats to the network
entity.
[0029] Optionally, in any of the preceding embodiments, wherein the
programming includes instructions to configure the first TRP to one
of retrieve the first formats and the subset of the subframes from
a memory, receive the first formats and the subset of the subframes
from a network entity determining formats of subframes supporting
access communications and formats of subframes supporting backhaul
communications, or receive the first formats and the subset of the
subframes from a third TRP.
[0030] In accordance with an example embodiment, a network entity
is provided. The network entity includes one or more processors,
and a computer readable storage medium storing programming for
execution by the one or more processors. The programming including
instructions to configure the network entity to select first
formats of first subframes supporting access communications at a
first TRP in accordance with TRP capabilities of the first TRP,
select second formats of second subframes supporting access
communications at a second TRP in accordance with TRP capabilities
of the second TRP, select a subset of the first formats and the
second formats for supporting backhaul communications between the
first TRP and the second TRP, wherein the subset of the first
formats and the second formats is selected in accordance with the
TRP capabilities of the first TRP and the second TRP, and signal
indications of the first formats of the first subframes, the second
formats of the second subframes, and the subset of the first
formats and the second formats to the first TRP and the second
TRP.
[0031] Optionally, in any of the preceding embodiments, wherein the
first and second TRPs are self-interference cancellation capable
within a single sector, and wherein the subset of the first formats
and the second formats comprises all formats of the first and
second formats.
[0032] Optionally, in any of the preceding embodiments, wherein one
of the first or second TRPs is self-interference cancellation
incapable within a single sector, and wherein the subset of the
first formats and the second formats comprises formats that
correspond to the one of the first or second TRPs that is
self-interference cancellation incapable.
[0033] Optionally, in any of the preceding embodiments, wherein the
first and second TRPs are self-interference cancellation incapable
within a single sector, and wherein the subset of the first formats
and the second formats comprises conflicting formats of the first
and second formats.
[0034] Practice of the foregoing embodiments enables the
implementation of low latency high bandwidth wireless connections
(backhaul and/or fronthaul) between network entities with existing
backhaul links (wireline or wireless) and network entities without
existing backhaul links. These low latency high bandwidth wireless
connections share network resources with access links in an IAB
solution. The IAB links may be in-band with the access links.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] For a more complete understanding of the present disclosure,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0036] FIG. 1A illustrates an example wireless communications
system according to example embodiments described herein;
[0037] FIG. 1B illustrates a communications system highlighting
interference at TRPs due to backhaul links and access links that
are located in the same sector while serving UEs by transmitting
and receiving in different directions according to example
embodiments described herein;
[0038] FIG. 1C illustrates a detailed view of an antenna array of a
TRP according to example embodiments described herein;
[0039] FIG. 1D illustrates a communications system highlighting
interference at TRPs due to communications on backhaul links
located in different sectors according to example embodiments
described herein;
[0040] FIG. 2A illustrates a bandwidth allocation diagram of a
frequency band used for backhaul links when access links use a
different frequency band according to example embodiments described
herein;
[0041] FIG. 2B illustrates bandwidth allocation diagrams of a
frequency band used for backhaul links when access links use the
same frequency band as the backhaul links according to example
embodiments described herein;
[0042] FIG. 3 illustrates a communications system highlighting
forward interference according to example embodiments described
herein;
[0043] FIG. 4A illustrates a communications system highlighting a
first form of self-interference according to example embodiments
described herein;
[0044] FIG. 4B illustrates a communications system highlighting a
second form of self-interference according to example embodiments
described herein;
[0045] FIG. 5 illustrates a communications system highlighting an
example configuration of the backhaul link communications when one
of the two TRPs is not full duplex capable according to example
embodiments described herein;
[0046] FIG. 6 illustrates a table of example TDD frame formats
according to example embodiments described herein;
[0047] FIG. 7A illustrates a communications system highlighting a
first example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable according to
example embodiments described herein;
[0048] FIG. 7B illustrates the communications system of FIG. 7A
highlighting a second example configuration of backhaul link
communications with neither of the two TRPs are full duplex capable
according to example embodiments described herein;
[0049] FIG. 7C illustrates a communications system highlighting a
third example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable according to
example embodiments described herein;
[0050] FIG. 7D illustrates a communications system highlighting a
fourth example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable according to
example embodiments described herein;
[0051] FIG. 8A illustrates a table of example TDD frame formats,
highlighting a first TDD frame selection according to example
embodiments described herein;
[0052] FIG. 8B illustrates a table of example TDD frame formats,
highlighting a second TDD frame selection according to example
embodiments described herein;
[0053] FIGS. 9A-9C illustrate different communications phases of a
TRP to TRP communications link to help mitigate different sector
interference in an AB implementation according to example
embodiments described herein;
[0054] FIG. 10 illustrates a communications phase diagram for a TRP
to TRP communications link whereby the TRP is capable of
simultaneously receiving and/or transmitting on different sectors
according to example embodiments described herein;
[0055] FIG. 11 illustrates a table summarizing different IAB
configuration restrictions in accordance with TRP capabilities
according to example embodiments described herein;
[0056] FIG. 12A illustrates a communications system highlighting a
first example TRP capabilities and requested access frame format
reporting configuration according to example embodiments described
herein;
[0057] FIG. 12B illustrates a communications system highlighting a
second example TRP capabilities and requested access frame format
reporting configuration according to example embodiments described
herein;
[0058] FIG. 13 illustrates a communications system highlighting an
example signaling of backhaul link and TDD frame formats to TRPs
according to example embodiments described herein;
[0059] FIG. 14 illustrates a flow diagram of example operations
occurring in a network entity that determines backhaul and access
link configurations according to example embodiments described
herein;
[0060] FIG. 15 illustrates a flow diagram of example operations
occurring in a TRP communicating using access and backhaul links in
an IAB deployment according to example embodiments described
herein;
[0061] FIG. 16 illustrates an example communication system
according to example embodiments described herein;
[0062] FIGS. 17A and 17B illustrate example devices that may
implement the methods and teachings according to this disclosure;
and
[0063] FIG. 18 is a block diagram of a computing system that may be
used for implementing the devices and methods disclosed herein.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0064] The making and using of the presently example embodiments
are discussed in detail below. It should be appreciated, however,
that the present disclosure provides many applicable inventive
concepts that can be embodied in a wide variety of specific
contexts. The specific embodiments discussed are merely
illustrative of specific ways to make and use the embodiments, and
do not limit the scope of the disclosure.
[0065] FIG. 1A illustrates an example wireless communications
system 100. Communications system 100 includes an access node 105
serving a plurality of user equipments (UEs), such as UE 110, UE
112, and UE 114. In a first operating mode, transmissions for UEs
as well as transmissions by UEs pass through the access node. The
access node allocates network resources for the transmissions to or
from the UEs. Access nodes may also be commonly referred to as base
stations, NodeBs, evolved NodeBs (eNBs), next generation (NG) eNBs
(gNBs), master eNBs (MeNBs), secondary eNBs (SeNBs), master gNBs
(MgNBs), secondary gNBs (SgNBs), remote radio heads, access points,
and the like, while UEs may also be commonly referred to as
mobiles, mobile stations, terminals, subscribers, users, stations,
and the like. An access node (or an eNB, gNB, remote radio head,
access point, and so on) that is serving one or more UEs may be
referred to as a serving base station (SBS). A transmission point
may be used to refer to any network entity capable of transmitting.
Therefore, transmission-reception points (TRP) commonly refer to
access nodes, eNBs, gNBs, base stations, NodeBs, MeNBs, SeNBs,
MgNBs, SgNBs, remote radio heads (RRHs), access points. In some
situations, UEs (and similar devices) may also be operating as
TRPs.
[0066] While it is understood that communications systems may
employ multiple access nodes (or TRPs) capable of communicating
with a number of UEs, only one access node, and five UEs are
illustrated for simplicity.
[0067] A cell is a commonly used term that refers to a coverage
area of an access node. Typically, a cell is served by one or more
sectors of a sectorized antenna of the access node. Hence, the
coverage area of the access node includes a cell partitioned into a
plurality of sectors. As an illustrative example, in a scenario
where an access node uses a three-sector antenna system, the cell
of the access node may be divided into three sectors, with each
sector being covered by a separate antenna (with an example beam
width of 120 degrees) or a separate part of the total antenna
system. As another illustrative example, in a scenario where an
access node uses a six-sector antenna system (where each antenna
may cover a 60 degree sector, for example), the cell of the access
node may be divided into six sectors or three sectors, with each
sector being covered by one or two antennas or parts sectors of the
antenna system respectively.
[0068] The discussion of interference, as presented herein, focuses
on the interference at the TRP due to operating backhaul links and
access links transmitting to or receiving from served UEs, with the
backhaul and access links being located in the same sector or in
different sectors. Interference, when the access links and the
backhaul links are in a single sector, occurs when the backhaul and
access links are operating in different directions. FIG. 1B
illustrates a communications system 130 highlighting interference
at TRPs due to backhaul links and access links that are located in
the same sector while serving UEs by transmitting and receiving in
different directions. Communications system 130 includes a first
TRP (TRP1) 135, a second TRP (TRP2) 137, a first UE (UE1) 139, and
a second UE (UE2) 141. As shown in FIG. 1B, the access links and
the backhaul links are located in the same sector due to the
relative positions of TRP1 135 and TRP2 137.
[0069] Interference at the TRP, may also occur due to transmitting
and receiving on backhaul links operating in different directions
of different sectors. FIG. 1C illustrates a detailed view of a set
of antenna array panels 150 of a TRP. Set of Antenna array panels
150, as shown in FIG. 1C, includes two array panels; a first panel
(array panel1) 155 is oriented at approximately 90 degrees and a
second panel (array panel2) 157 that is oriented at approximately
45 degrees. When a transmission occurs at array panel1 155, leakage
occurs and a receiver at array panel2 157 receives a portion of the
transmission at array panel1 155. FIG. 1D illustrates a
communications system 170 highlighting interference at TRPs due to
communications on backhaul links located in different sectors.
Communications system 170 includes a first TRP (TRP1) 175, a second
TRP (TRP2) 177, and a third TRP (TRP3) 179. As shown in FIG. 1D,
when TRP1 175 is transmitting to TRP3 179, leakage occurs onto a
receiver of TRP1 175 that is also receiving a transmission from
TRP2 177. The leakage arising from the transmission between TRP1
175 and TRP3 179 may negatively impact the reception of the
transmission between TRP2 177 and TRP1 175.
[0070] FIG. 2A illustrates a bandwidth allocation diagram 200 of a
frequency band used for backhaul links when access links use a
different frequency band. As shown in FIG. 2A, the entirety of the
frequency band used for the backhaul links is usable by the
backhaul links because the access links uses a different frequency
band. This particular configuration is typically used in some
configurations of 3GPP LTE Advanced (LTE-A) for links between eNBs,
MeNBs, SeNBs, RRHs, and so on. It is noted that although the
discussion focuses on backhaul links, the example embodiments
presented herein are also operable with fronthaul links. Therefore,
the focus on backhaul links should not be construed as being
limiting to either the scope or spirit of the example
embodiments.
[0071] FIG. 2B illustrates bandwidth allocation diagrams of a
frequency band used for backhaul links when access links use the
same frequency band as the backhaul links. The same spectral
resources may be multiplexed for an integrated access and backhaul
(IAB) deployment when backhaul and access are multiplexed using
frequency division multiplexing (FDM), time division multiplexing
(TDM), and/or spatial division multiplexing (SDM). A first
bandwidth allocation diagram 250 illustrates a situation wherein
the high frequency band is shared between the backhaul link and
access using frequency division multiple access (FDMA) and is
partitioned into at least two portions, with a first high frequency
portion is allocated to the backhaul link and a second high
frequency portion allocated to the access. A second bandwidth
allocation diagram 270 illustrates a situation wherein the
frequency band is shared using time division multiple access (TDMA)
or spatial division multiple access (SDMA). If TDMA is used, the
backhaul link is assigned to use the high frequency band at
specific times and the access is assigned to use the high frequency
band at other specific times. If SDMA is used, the high frequency
backhaul link is assigned to use the frequency band only in
specific spatial orientations (or beam directions) and the access
is assigned to use the same frequency band in other specific
spatial orientations (or beam directions), where the spatial
orientations may change as a function of time.
[0072] In contrast to TDM, SDM may be used in an IAB deployment to
allow access links and backhaul links to share the same spectral
resources simultaneously. The spectral efficiency of SDM may
potentially be higher than that of TDM. However, the potential
interference caused by spatial multiplexing the access links and
the backhaul links may need to be carefully managed to realize the
potential gains promised by SDM over TDM.
[0073] In a beamformed environment, the transmission and/or
reception of beamformed backhaul links from one TRP to its
neighboring TRPs may need to be coordinated, thereby requiring the
consideration of a variety of interference issues.
[0074] FIG. 3 illustrates a communications system 300 highlighting
forward interference. Forward interference may be viewed as
interference in the same direction. Communications system 300
includes a first TRP (TRP1) 305, a second TRP (TRP2) 307, and a UE
309. TRP1 305 has an access link 320 with UE 309. TRP1 305 has a
backhaul link 325 with TRP2 307. Forward interference may occur
when TRP1 305 is transmitting on backhaul link 325 to TRP2 307 at
the same time when it is transmitting on access link 320 to UE 309.
The transmission on backhaul link 325 to TRP2 307 may appear on
access link 320 and received by UE 309.
[0075] In general, the amount of forward interference may depend
upon factors such as: [0076] The beamforming (or precoding) used
for the backhaul link; [0077] The beamforming (or precoding) used
for the access link; and [0078] The angle (in the vertical and/or
horizontal planes) between the access link and the backhaul link.
It is noted that the angle between the access link and the backhaul
link may be different for different scheduled UEs.
[0079] Solutions for dealing with forward interference may be
similar to techniques related to multi-user (MU) multiple input
multiple output (MU-MIMO). In a first solution, if there is a large
pool of UEs to select from to perform co-scheduling with the
backhaul link, the problem of forward interference may be solved
using scheduling algorithms, which may take into account the
radiation pattern of the beamformed backhaul links (which are
generally fixed) into consideration to make the co-scheduling
considerations. As an example, the radiation pattern (or
information related to the radiation pattern) of the beamformed
backhaul links may be stored in a lookup table, such as a
two-dimensional lookup table. In a second solution, if the number
of UEs to select from is low, and the UEs have small angular
distance to the backhaul links, advanced linear or non-linear
precoding algorithms may be used to reduce the effects of forward
interference.
[0080] FIG. 4A illustrates a communications system 400 highlighting
a first form of self-interference. Self-interference may also be
referred to as cross interference. Communications system 400
includes a first TRP (TRP1) 405, a second TRP (TRP2) 407, a first
UE (UE1) 409, and a second UE (UE2) 411. TRP1 405 has an access
link 420 with UE1 409, while TRP2 407 has an access link 422 with
UE2 411. TRP1 405 has a backhaul link 425 with TRP2 407. When TRP1
405 is receiving in access link 420 from UE1 409 (e.g., during an
uplink access subframe) while transmitting in backhaul link 425 to
TRP2 407 (e.g., during a downlink backhaul subframe),
self-interference may occur due to the high transmission power of
the TRP1 405 to TRP2 407 backhaul transmission leaking into an
uplink receiver of TRP1 405 that is receiving an uplink
transmission on access link 420 between TRP1 405 and UE1 409. This
form of cross-interference may not depend upon the location of UE
409 and is similar to self-interference in a full-duplex
receiver.
[0081] FIG. 4B illustrates a communications system 450 highlighting
a second form of self-interference. Communications system 450
includes a first TRP (TRP1) 455, a second TRP (TRP2) 457, a first
UE (UE1) 459, and a second UE (UE2) 461. TRP1 455 has an access
link 470 with UE1 459, while TRP2 457 has an access link 472 with
UE2 461. TRP1 455 has a backhaul link 475 with TRP2 457. When TRP1
455 is receiving in backhaul link 475 from TRP2 457 (e.g., during
an uplink backhaul subframe) and transmitting in access link 470 to
UE1 459 (e.g., during a downlink access subframe),
self-interference may occur as the downlink access link
transmission to UE1 459 self interferes into an uplink receiver of
TRP1 455 that is receiving an uplink transmission on backhaul link
475 between TRP1 455 and TRP2 457.
[0082] Coping with self-interference may require a special TRP type
that is capable of performing wideband (up to several gigahertz or
more of bandwidth) self-interference cancellation (SIC), which
would allow the TRP to operate in full duplex mode. It is noted
that not all types of TRPs are capable of full duplex operations.
The ability to operate in full duplex mode is a TRP capability.
Hence, it is possible for the TRPs associated with a particular
backhaul link to have different TRP capability.
[0083] According to an example embodiment, the configuration of the
backhaul link communications is based upon the TRP capability of
the TRPs which are associated with the backhaul link. In particular
the TRP capability of TRPs to handle and receive signals at the
same time, i.e., full duplex capability. As an example, in a
backhaul link involving two TRPs, different configurations of the
backhaul link exist for situations when both TRPs are full duplex
capable, one TRP is not full duplex capable, or neither TRP are
full duplex capable. A different configuration of the backhaul link
communications may be specified for each of the three different
situations.
[0084] According to an example embodiment, in a situation where
both TRPs are full duplex capable, the configuration of the
backhaul link communications allows the two TRPs to transmit and/or
receive at any time because the two TRPs are full duplex
capable.
[0085] According to an example embodiment, in a situation when one
or both of the TRPs are not full duplex capable, the configuration
of the backhaul link communications is restricted in accordance
with the subframe configurations for the access link involving the
TRPs.
[0086] FIG. 5 illustrates a communications system 500 highlighting
an example configuration of the backhaul link communications when
one of the two TRPs is not full duplex capable. Communications
system 500 includes a first TRP (TRP1) 505, a second TRP (TRP1)
507, a first UE (UE1) 509, and a second UE (UE2) 511. TRP1 505 is
full duplex capable while TRP2 507 is not full duplex capable. UE1
509 uses TDD frame format 515 for access with TRP1 505, while UE2
511 uses TDD frame format 517 for access with TRP2 507. As shown in
FIG. 5, the two TDD frame formats are identical. However, it is not
required that the TDD frame formats be the same. Frame formats,
such as TDD frame formats 515 and 517, specify transmission
allocations of subframes of radio frames. Therefore, a single frame
format corresponds to a plurality of subframe formats. As an
example, in 3GPP LTE compliant communications systems, a subframe
may be allocated for downlink transmissions, uplink transmissions,
or special. Other communications systems may have different
transmission allocations of subframes. The transmission allocation
for a single subframe is referred to as a subframe format. Although
the discussion presented herein focuses on frame formats, subframe
formats may be used in its place without loss of generality.
[0087] Because TRP1 505 is full duplex capable, TRP1 505 may
perform backhaul communications at any time; TRP1 505 may use SIC
to cancel interference or the transmitter and receiver may have
sufficient separation or isolation to handle the self-interference,
for example. However, TRP2 507 is not full duplex capable, so TRP2
507 can only perform backhaul communications at certain times. In
order to prevent self-interference, TRP2 507 makes a backhaul
transmission to TRP1 505 only during TDD subframes that are
allocated as downlink subframes, such as subframes 520 and 522, and
makes a backhaul reception from TRP1 505 only during TDD subframes
that are allocated as uplink subframes, such as subframes 524. FIG.
5 illustrates a TRP arrangement for subframes 520 or 522. Although
the number of subframes available for backhaul communications is
limited, the restriction may still be manageable due to the high
data rates (i.e., a high modulation and coding scheme (MCS) level,
e.g., 256 quadrature amplitude modulation (QAM), is used) supported
in the backhaul.
[0088] However, depending upon the MCS used for the backhaul link
and the total amount of backhaul data being transmitted for the
TRPs (e.g., number of TRPs * data rate per TRP), the communications
system (e.g., an entity in the communications system) may elect to
restrict the use of TDD frame formats for access. As an example,
frame formats that contain dominant number of uplink subframes may
be selected to allow sufficient capacity for the backhaul link in
both directions of the backhaul link.
[0089] FIG. 6 illustrates a table 600 of example TDD frame formats.
Table 600 presents seven example frame formats with differing
periodicities. Each frame includes 10 subframes, with each subframe
possibly being allocated for downlink transmissions (denoted "D"),
uplink transmissions (denoted "U"), or special (denoted "S"). In
other words, each subframe has a subframe format of D, U, or S.
Subframes (in order from subframe 0 to subframe 9) of frame 605 are
allocated for downlink, special, uplink, uplink, uplink, downlink,
special, uplink, uplink, and uplink. Subframes of frame 607 are
allocated for downlink, special, uplink, downlink, downlink,
downlink, downlink, downlink, downlink, and downlink, while
subframes of frame 609 are allocated for downlink, special, uplink,
uplink, uplink, downlink, special, uplink, uplink, and
downlink.
[0090] As discussed previously, in order to support backhaul
communications, frame formats that include a dominant number of
uplink subframes may be selected. Hence, frames 605 and 607 may be
restricted, while frames with dominant number of uplink subframes,
such as frame 609, may be selected.
[0091] According to an example embodiment, in a situation when both
of the TRPs are not full duplex capable, a backhaul transmission
from a first TRP to a second TRP takes place during a time interval
associated with a subframe (of a first UE served by the first TRP)
that is allocated for downlink transmissions and a subframe (of a
second UE served by the second TRP) that is allocated for uplink
transmissions. This different subframe allocation for the two
subframes associated with the same time interval is referred to as
a conflict subframe. The use of the time interval associated with
the conflict subframe for access prevents self-interference at
receiving TRPs that are non-full duplex capable.
[0092] When neither of the TRPs involved in communications over a
backhaul link are full duplex capable, backhaul communications may
still be possible but may be limited to situations where conflict
subframes exist in the TDD frame formats for access of the TRPs. In
a similar manner, flexible TDD may be operable in such a scenario.
If backhaul communications is needed in both directions within a
single frame, a TDD frame format with at least one conflict
subframe is required for each of the two directions of the backhaul
communications.
[0093] FIG. 7A illustrates a communications system 700 highlighting
a first example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable. Communications
system 700 includes a first TRP (TRP1) 705, a second TRP (TRP1)
707, a first UE (UE1) 709, and a second UE (UE2) 711. TRP1 705 and
TRP2 707 are not full duplex capable. TRP1 705 uses TDD frame
format 715 for access with UE1 709, while TRP2 707 uses TDD frame
format 717 for access with UE2 711. It is noted that the two TDD
frame formats are different.
[0094] Because neither TRPs are full duplex capable, in-band
backhaul can only be achieved under certain conditions. In order to
prevent self-interference TRP2 707 may only make a backhaul
transmission to TRP1 705 during access subframes which are
allocated for downlink transmissions (i.e., subframes allocated for
access transmissions from TRP2 707 to UE2 711). In addition to the
restriction on the access subframe for TRP2 707, TRP2 707 may also
only make a backhaul transmission to the receiving TRP1 705 during
an access subframe allocated for uplink reception at TRP1 705
(i.e., subframes allocated for access transmissions from UE1 709 to
TRP1 705 (subframes that are allocated for uplink transmissions
from the UEs served by TRP1 705)) in order to meet the non-full
duplex capability of TRP1 705. In other words, the backhaul
transmissions between a first TRP to a second TRP only take place
during time intervals associated with conflict subframes, with the
access subframe of a UE served by the first TRP (the transmitting
TRP) being allocated as a downlink access subframe. As an example,
subframe 720 of TDD frame format 717 and subframe 722 of TDD frame
format 715 are conflict subframes and allocated accordingly to meet
the non-full duplex capabilities of the TRPs.
[0095] FIG. 7B illustrates communications system 700 highlighting a
second example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable. As shown in FIG.
7B, TRP1 705 has a backhaul transmission for TRP2 707. In order to
prevent self-interference, TRP1 705 may only make the backhaul
transmission to TRP2 707 during access subframes which are
allocated for downlink transmission (i.e., subframes allocated for
access transmissions from TRP1 705 to UE1 709). In addition to the
restriction on the access subframe for TRP1 705, TRP1 705 may also
only make a backhaul transmission to the receiving TRP2 707 during
an access subframe allocated for uplink reception at TRP2 707
(i.e., subframes allocated for access transmissions from UE2 711 to
TRP2 707 (subframes that are allocated for uplink transmissions
from UEs served by TRP2 707)) in order to meet the non-full duplex
capability of TRP2 707. As an example, subframe 755 of TDD frame
format 715 and subframe 757 of TDD frame format 717 are conflict
subframes and allocated accordingly to meet the non-full duplex
capabilities of the TRPs.
[0096] FIG. 7C illustrates a communications system 760 highlighting
a third example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable. Communications
system 760 includes a first TRP (TRP1) 765, a second TRP (TRP2)
767, and a UE 769. TRP1 765 and TRP2 767 are not full duplex
capable. The TRPs utilize TDD frame formats that are not
constrained to a fixed set of formats. In other words, the TRPs may
use a self-constrained new sub-frame type, such as those presented
below. In such a situation, it is possible to have a transmission
gap in the backhaul and/or access subframes. The transmission gap
may be used to accommodate the half-duplex requirements of the
communications system. As shown in FIG. 7C, TRP1 765 is receiving
downlink backhaul communications from TRP2 767 (such as in interval
770) at the same time as it is receiving uplink access
communications from UEs (e.g., UE 769) in its coverage area (such
as in interval 774). In this situation, portions of the frame are
blanked out because TRP1 765 does not have a sufficient number of
UEs to schedule for uplink communications. It is noted that the
intervals (such as interval 770 and interval 774) comprises one or
more subframes.
[0097] FIG. 7D illustrates a communications system 760 highlighting
a fourth example configuration of backhaul link communications with
neither of the two TRPs are full duplex capable. FIG. 7D presents a
reverse case of the situation shown in FIG. 7D, with TRP1 765
performing downlink access communications with UEs (e.g., UE 769)
in its coverage area (such as in interval 782) and uplink backhaul
communications with TRP2 767 (such as in interval 784). In this
situation, because the amount of data for the uplink backhaul data
and the downlink access data are similar, no blanking is required.
It is noted that the intervals (such as interval 782 and interval
784) comprises one or more subframes.
[0098] Although the TDD frame formats shown in FIGS. 7A and 7B
support backhaul communications in situations where neither TRP is
full duplex capable, however, cross interference across cell
boundaries (UE to UE interference) still persists. In beamformed
communications, several solutions are available to mitigate the
interference across cell boundaries. In order to enable sufficient
capacity for SDMA backhaul communications in such situations, TDD
frames for access may be selected to have a sufficient number of
subframes that are in different directions. This may restrict the
choice of TDD access frames for neighboring TRPs. The extent of the
restrictions may be dependent upon the amount of backhaul data
needed and the data rates that can be supported (i.e., MCS level)
used for the backhaul link.
[0099] FIG. 8A illustrates a table 800 of example TDD frame
formats, highlighting a first TDD frame selection. The frame
formats shown in table 800 are for 3GPP LTE-A, however frame
formats for other communications systems may be different. As shown
in FIG. 8A, if a first TRP uses TDD frame format 805 and a second
TRP uses TDD frame format 807, there are two conflict subframes
(shown as shaded subframes) with the subframe allocations for each
of the two the conflict subframes changing between the conflict
subframes.
[0100] FIG. 8B illustrates a table 850 of example TDD frame
formats, highlighting a second TDD frame selection. As shown in
FIG. 8B, if a first TRP uses TDD frame format 855 and a second TRP
uses TDD frame format 857, there are five conflict subframes (shown
as shaded subframes). However, the conflict subframes are all in
the same direction. With the TDD frame formats, as selected, only
the first TRP will be able to make transmissions on the backhaul
link during the TDD frame.
[0101] In a future Fifth Generation (5G) (and later) communications
system, there may be more than two different types of subframe
allocations (or subframe types), such as: [0102] Downlink (denoted
"D"); [0103] Uplink (denoted "U"); [0104] Self-constrained new
subframe type "D" for data (contains "U" and "D" for control); and
[0105] Self-constrained new subframe type "U" for data (contains
"U" and "D" for control).
[0106] It is not yet known in 5G communications systems if uplink
and/or downlink TDD frame formats will be constrained to a finite
set of formats (e.g., such as the seven frame configurations for
3GPP LTE-A) with possibly a larger number of different formats or
if each subframe format or type in the frame will be totally
flexibly defined. Whatever way the TDD frame for access is designed
in 5G and later communications systems, SDMA backhaul
communications will be possible when the subframes of neighboring
TRPs are conflict subframes (i.e., subframes are in different
directions).
[0107] The discussion presented previously has focused on same
sector interference. In order to support different sector
interference, additional interference mitigation may be provided.
In a co-assigned U.S. Provisional Patent Application entitled
"System and Method for Time Division Duplexed Multiplexing in
Transmission-reception Point to Transmission-Reception Point
Connectivity", Application No. 62/341,877, Filed May 26, 2016, and
U.S. Patent Application entitled "System and Method for Time
Division Duplexed Multiplexing in Transmission-reception Point to
Transmission-Reception Point Connectivity", application Ser. No.
15/289,926, Filed Oct. 10, 2106, which are hereby incorporated
herein by reference, techniques for different sector backhaul
communications between TRPs are presented.
[0108] FIGS. 9A-9C illustrate different communications phases of a
TRP to TRP communications link to help mitigate different sector
interference in an IAB implementation. FIG. 9A illustrates a
transmit phase 900. In transmit phase 900, TRP 905 transmits using
all available transmit beams. The transmission using all available
transmit beams ensure that all sectors of TRP 905 are covered for
backhaul and access links (although only the backhaul
communications (backhaul transmissions) to neighboring TRPs are
shown). FIG. 9B illustrates a first receive phase 910. In first
receive phase 910, TRP 905 receives using a first subset of
available receive beams. As an illustrative example, the first
subset of available receive beams includes approximately one-half
of the receive beams of TRP 905, with the distribution of the
receive beams arranged so that the receive beams of the first
subset is about evenly distributed. FIG. 9C illustrates a second
receive phase 920. In second receive phase 920, TRP 905 receives
using a second subset of available receive beams. As an
illustrative example, the second subset of available receive beams
includes the remaining receive beams of TRP 905, with the
distribution of the receive beams arranged so that the receive
beams of the second subset is about evenly distributed. Hence, the
combination of first receive phase 910 and second receive phase 920
ensures that all sectors of TRP 905 are covered for the receiving
of backhaul and access links.
[0109] It is noted that although FIGS. 9A-9C present the situation
with a single transmit phase and two receive phases, other
combinations of transmit and receive phases are possible. As an
illustrative example, an alternate situation may include a single
receive phase and two transmit phases. Another alternate situation
may include a single transmit phase and three (or more) receive
phases, or a single receive phase and three (or more) transmit
phases. In yet another alternate situation, there may be two (or
more) transmit phases and two (or more) receive phases.
[0110] FIG. 10 illustrates a communications phase diagram 1000 for
a TRP to TRP communications link wherein the TRP is capable of
simultaneously receiving and/or transmitting on different sectors.
If the TRP, e.g., TRP 1005, is capable of simultaneously receiving
and/or transmitting on different sectors, much greater flexibility
is possible. In such a situation, the TRP may be able to
simultaneously receive and/or transmit on backhaul and access links
in a single phase, as shown in FIG. 10.
[0111] FIG. 11 illustrates a table 1100 summarizing different IAB
configuration restrictions in accordance with TRP capabilities.
Table 1100 summarizes restrictions on IAB configurations for
backhaul links and TDD frames for access links in accordance with
the SDM and TRP capability (e.g., full duplex capable or non-full
duplex capable) of one or more of the TRPs associated with a
backhaul link. As an example, row 1105 corresponds to a situation
where both TRPs of a backhaul link are full duplex capable within
the same sector and across different sectors. In such a situation,
there are no restrictions on the backhaul configuration. Row 1110
corresponds to a situation where one of the TRPs of a backhaul link
is non-full duplex capable with the same sector, but is full duplex
capable across different sectors. In such a situation, IAB
operation is limited by the TDD access frame of the non-full duplex
capable TRP.
[0112] Row 1115 corresponds to a situation where one of the TRPs of
a backhaul link is non-full duplex capable in the same sector and
one of the TRPs is also non-full duplex capable across different
sectors. In such a situation, IAB operation is limited by the TDD
access frame of the non-full duplex capable TRP. Additionally, the
particular TRP can only simultaneously transmit and/or receive from
all neighbor TRPs (as an example, consider the configuration shown
and discussed in FIGS. 9A-9C). Row 1120 corresponds to a situation
where both TRPs are non-full duplex capable with the same sector
(in such a situation, it does not matter the TRP capability across
different sectors). In such a situation, IAB operation is limited
to conflict subframes of the TRPs involved (such as shown in FIGS.
7A and 7B). Additional restrictions may be imposed if some TRPs are
not full duplex capable across different sectors.
[0113] According to an example embodiment, TRP capabilities are
signaled to other network entities (such as eNBs, gNBs, adjacent
TRPs, etc.) using an interface, including an X2 interface or some
other future generation X2 like interface, to enable the selection
of backhaul and access link configurations. The TRP capabilities
may be used in a system and method for supporting backhaul and
access operation in beamformed communications systems to
accommodate TRPs with differing capabilities.
[0114] As an illustrative example, TRP capability, in the form of
an IAB capability word, is signaled. An example IAB capability word
is as follows:
[0115] Bit 1--SDM capable (`0`--no, `1`--yes);
[0116] Bit 2--FDM capable (`0`--no, `1`--yes);
[0117] Bit 3--FDM capable (`0`--no, `1`--yes);
[0118] additional bits may be used to indicate other capabilities,
such as CDM, and so on. Each TRP may have its own IAB capability
word.
[0119] In a situation where a TRP is able to support multiple IAB
configurations (e.g., multiple `1` values in its IAB capability
word), a selected IAB configuration may utilize a combination of
multiple schemes simultaneously.
[0120] In addition to the actual multiplexing backhaul capability
configuration that each TRP is capable of supporting (SDM, TDM,
FDM, and so on), the network may also need to know how each TRP can
handle transmitting and receiving (or vice versa) on access links
and backhaul links simultaneously in the same sector or across
different sectors. Such ability is of importance to TDM and SDM
based methods. The TRP's capability to communicate on access and
backhaul links in the same sector or across different sectors may
be referred to as the TRP's self-interference capability, which may
be presented in the form of a multi-valued indicator. An example
multi-valued indicator indicating a TRP's self-interference
capability includes:
[0121] `00`--TRP is not capable of transmitting and/or receiving
signals at the same time or frequency;
[0122] `01`--TRP is only capable of transmitting and/or receiving
signals at the same time or frequency across different sectors or
array panels (additional values may be used to indicate an exact
sector offset(s) supported);
[0123] `10`--TRP is capable of transmitting and/or receiving
signals at the same time or frequency, irrespective of sector (both
in same sector or across different sectors); and
[0124] `11`--TRP is only capable of transmitting and/or receiving
signals at the same time or frequency in same sector or array
panel.
[0125] In addition to the TRP capability and the TRP
self-interference capability, a TRP may also indicate a preference
for a particular TDD frame format for access links. A TRP's
preference for a particular TDD frame format may be indicated by
using a multi-valued frame format indicator, the length of which is
dependent upon the number of possible TDD frame formats. As an
illustrative example, 3GPP LTE has seven TDD frame formats;
therefore, indicating a preference of one of the seven 3GPP LTE TDD
frame formats would require at least a three bit long frame format
indicator.
[0126] FIG. 12A illustrates a communications system 1200
highlighting a first example TRP capabilities and requested access
frame format reporting configuration. Communications system 1200
includes a TRP (TRP X) 1205, a neighboring TRP 1210, and a higher
level network entity 1215. Higher level network entity 1215 may be
a dedicated stand-alone backhaul and access link configuration
determination entity. Alternatively, higher level network entity
1215 may be co-located with another network entity, such as a gNB,
eNB, central controller, and so on.
[0127] According to the first example TRP capabilities and
requested access frame format reporting configuration, each TRP
reports its own IAB capability, TRP self-interference capability,
and requested access frame format indicator to higher level network
entity 1215. As shown in FIG. 12A, TRP X 1205 and neighboring TRP
1210 separately report their IAB capability, TRP self-interference
capability, and requested access frame format indicator to higher
level network entity 1215. The TRPs may also share the TRP
capabilities (IAB and self-interference) and requested access frame
format amongst themselves.
[0128] The reporting of the IAB capability, TRP self-interference
capability, and requested frame format indicator may occur
statically, semi-statically, or dynamically. The reporting may take
place over an X2 interface or some other next generation X2
interface which may be wired or wireless. Depending upon how a
particular TRP is connected, different TRPs may use different
interfaces to report the TRP capabilities. The different TRPs may
also report the various TRP capabilities at the same rate or at
different rates. As an example, the requested access frame
structure indicator may be reported dynamically or at a higher rate
than the IAB capability.
[0129] FIG. 12B illustrates a communications system 1250
highlighting a second example TRP capabilities and requested access
frame format reporting configuration. Communications system 1250
includes a TRP (TRP X) 1255, a neighboring TRP 1260, and a higher
level network entity 1265. According to the second example TRP
capabilities and requested access frame format reporting
configuration, one or more neighboring TRPs (e.g., neighbor TRP
1260) report their respective TRP capabilities and requested access
frame structure to a particular TRP (e.g., TRPX 1255) and the
particular TRP reports the TRP capabilities and requested access
frame format of the one or more neighboring TRPs, along with its
own TRP capabilities and requested access frame format, to higher
level network entity 1265.
[0130] An example situation wherein the second example TRP
capabilities and requested access frame format reporting
configuration may be used involves a temporary TRPs (e.g., TRPs
deployed for special events, such as concerts, conventions, sports
events, and so on), mobile TRPs (e.g., TRPs located on buses,
trains, cars, any airborne vessel (i.e. balloon, plane, drones,
etc.), or any water vessel (boats, ships, ferries, etc.) and so
forth), or dynamic TRPs (e.g., TRPs that turn on and off at
specific times, events, etc.) are used. These temporary TRPs can
report their TRP capabilities and requested access frame format to
more stable (e.g., permanently deployed) TRPs in their
neighborhood. The more stable TRPs can report the TRP capabilities
and requested access frame format of the temporary TRPs (along with
their own TRP capabilities) to higher level network entity 1265.
Such a deployment enables the implementation of a self-organizing
network.
[0131] FIG. 13 illustrates a communications system 1300
highlighting an example signaling of backhaul link and TDD frame
formats to TRPs. Communications system 1300 includes a TRP (TRP X)
1305, a higher level network entity 1310, a memory 1315, and a
neighbor TRP 1320. Higher level network entity 1310 may be a
dedicated stand-alone backhaul and access link configuration
determination entity. Alternatively, higher level network entity
1310 may be co-located with another network entity, such as a gNB,
eNB, central controller, and so on.
[0132] TRP X 1305 may receive the backhaul link and TDD frame
formats from a memory database (located in memory 1315, which may
be local to TRP X 1305 or remote), higher level network 1310, or
neighbor TRP 1320 (neighbor TRP 1320 may be a master TRP that is
responsible for providing the backhaul link and TDD frame formats
to the TRPs that it is controlling. As discussed previously, the
backhaul link and TDD frame format may be signaled over a wireline
or wireless connection (such as X2 or next generation X2
connections). A proprietary connection may be used if memory 1315
is local to TRP X 1305.
[0133] Parameters for TDD backhaul frame configurations may include
a TDD frame format, if there is a fixed set of frame formats.
Alternatively, backhaul frame length may be specified and each
subframe type for the backhaul link may be specified for the
duration of the backhaul frame.
[0134] Depending upon the capability of the TRP to receive and
transmit to different neighboring TRPs at the same time (i.e., the
TRP is self-interference capable across different sectors): for the
TRPs that are self-interference capable across different sectors,
each TRP may be assigned a different backhaul frame format (or
subframes formats) for each neighboring TRP; or for the TRPs that
are not self-interference capable across different sectors, each
TRP may be assigned the same backhaul frame format (or subframes
formats) for all neighboring TRPs.
[0135] Parameters for TDD access frame formats may include a TDD
frame format, if there is a fixed set of frame formats, or subframe
formats. Alternatively, access frame length may be specified and
each subframe format or type for access may be individually
specified for the duration of the access frame.
[0136] FIG. 14 illustrates a flow diagram of example operations
1400 occurring in a network entity that determines backhaul and
access link configurations. Operations 1400 may be indicative of
operations occurring in a network entity that determines backhaul
and access link configurations.
[0137] Operations 1400 begin with the network entity determining
TRP capabilities and requested frame format for access (block
1405). The TRP capabilities may include IAB capability and TRP
self-interference capability, while the requested frame format may
comprise a requested frame format for access indicator. The TRP
capabilities and requested frame format may be received from each
TRP served by the network entity. Alternatively, a TRP (e.g., a
master TRP) may report its own TRP capability and requested frame
format along with the TRP capabilities and requested frame format
of TRPs that it controls. The network entity selects an access
frame format (block 1407). The network entity selects the access
frame format in accordance with the TRP capabilities and requested
frame format. The network entity may select an access frame format
for each TRP. Alternatively, the network entity may select an
access frame format for a plurality of TRPs, based on a particular
restriction imposed by their TRP capabilities and requested frame
formats. The network entity selects a backhaul frame format for the
TRPs (block 1409). The network entity selects the backhaul frame
format in accordance with the TRP capabilities and requested frame
formats, as well as the access frame format. The network entity may
select a backhaul frame format for each TRP. Alternatively, the
network entity may select a backhaul frame format for a plurality
of TRPs, based on a particular restriction imposed by their TRP
capabilities and requested frame formats. The network entity shares
the selected frame formats (block 1411). The network entity may
signal the selected frame formats to the TRPs. Alternatively, the
network entity may signal the selected frame formats to a subset of
the TRPs and the TRPs in the subset of TRPs may signal the selected
frame formats to the remaining TRPs. Alternatively, the network
entity may save the selected frame formats to a database, allowing
the TRPs to access the selected frame formats as needed. Although
the discussion presented above focuses on frame formats, the
example embodiments are operable with subframe formats. Therefore,
the discussion of frame formats should not be construed as being
limiting to either the scope or the spirit of the example
embodiments.
[0138] FIG. 15 illustrates a flow diagram of example operations
1500 occurring in a TRP communicating using access and backhaul
links in an IAB deployment. Operations 1500 may be indicative of
operations occurring in a TRP that is communicating using access
and backhaul links in an IAB deployment.
[0139] Operations 1500 begin with the TRP sending TRP capabilities
and requested frame format for access (block 1505). The TRP may
send the TRP capabilities and requested frame format to a network
entity that determines backhaul and access link formats.
Alternatively, the TRP may send the TRP capabilities and requested
frame format to another TRP (e.g., a master TRP) and the other TRP
sends the TRP capabilities and requested frame format to the
network entity. In an embodiment, the TRP may be a master TRP and
receives TRP capabilities and requested frame format from TRPs that
it is controlling. In such an embodiment, the TRP sends its own TRP
capabilities and requested frame format along with the TRP
capabilities and requested frame format that it receives to the
network entity. The TRP determines its access frame format (block
1507) and its backhaul frame format (block 1509). The access and
backhaul frame formats may be received from the network entity.
Alternatively, the access and backhaul frame formats may be
retrieved from a database. Alternatively, the access and backhaul
frame formats may be received from another TRP, such as a master
TRP. The TRP communicates according to the access and backhaul
frame formats (block 1511).
[0140] FIG. 16 illustrates an example communication system 1600. In
general, the system 1600 enables multiple wireless or wired users
to transmit and receive data and other content. The system 1600 may
implement one or more channel access methods, such as code division
multiple access (CDMA), time division multiple access (TDMA),
frequency division multiple access (FDMA), orthogonal FDMA (OFDMA),
single-carrier FDMA (SC-FDMA), or non-orthogonal multiple access
(NOMA).
[0141] In this example, the communication system 1600 includes
electronic devices (ED) 1610a-1610c, radio access networks (RANs)
1620a-1620b, a core network 1630, a public switched telephone
network (PSTN) 1640, the Internet 1650, and other networks 1660.
While certain numbers of these components or elements are shown in
FIG. 16, any number of these components or elements may be included
in the system 1600.
[0142] The EDs 1610a-1610c are configured to operate and/or
communicate in the system 1600. For example, the EDs 1610a-1610c
are configured to transmit and/or receive via wireless or wired
communication channels. Each ED 1610a-1610c represents any suitable
end user device and may include such devices (or may be referred
to) as a user equipment/device (UE), wireless transmit/receive unit
(WTRU), mobile station, fixed or mobile subscriber unit, cellular
telephone, personal digital assistant (PDA), smartphone, laptop,
computer, touchpad, wireless sensor, or consumer electronics
device.
[0143] The RANs 1620a-1620b here include base stations 1670a-1670b,
respectively. Each base station 1670a-1670b is configured to
wirelessly interface with one or more of the EDs 1610a-1610c to
enable access to the core network 1630, the PSTN 1640, the Internet
1650, and/or the other networks 1660. For example, the base
stations 1670a-1670b may include (or be) one or more of several
well-known devices, such as a base transceiver station (BTS), a
NodeB (NodeB), an evolved NodeB (eNodeB), a Home NodeB, a Home
eNodeB, a site controller, an access point (AP), or a wireless
router. The EDs 1610a-1610c are configured to interface and
communicate with the Internet 1650 and may access the core network
1630, the PSTN 1640, and/or the other networks 1660.
[0144] In the embodiment shown in FIG. 16, the base station 1670a
forms part of the RAN 1620a, which may include other base stations,
elements, and/or devices. Also, the base station 1670b forms part
of the RAN 1620b, which may include other base stations, elements,
and/or devices. Each base station 1670a-1670b operates to transmit
and/or receive wireless signals within a particular geographic
region or area, sometimes referred to as a "cell." In some
embodiments, multiple-input multiple-output (MIMO) technology may
be employed having multiple transceivers for each cell.
[0145] The base stations 1670a-1670b communicate with one or more
of the EDs 1610a-1610c over one or more air interfaces 1690 using
wireless communication links. The air interfaces 1690 may utilize
any suitable radio access technology.
[0146] It is contemplated that the system 1600 may use multiple
channel access functionality, including such schemes as described
above. In particular embodiments, the base stations and EDs
implement LTE, LTE-A, and/or LTE-B. Of course, other multiple
access schemes and wireless protocols may be utilized.
[0147] The RANs 1620a-1620b are in communication with the core
network 1630 to provide the EDs 1610a-1610c with voice, data,
application, Voice over Internet Protocol (VoIP), or other
services. Understandably, the RANs 1620a-1620b and/or the core
network 1630 may be in direct or indirect communication with one or
more other RANs (not shown). The core network 1630 may also serve
as a gateway access for other networks (such as the PSTN 1640, the
Internet 1650, and the other networks 1660). In addition, some or
all of the EDs 1610a-1610c may include functionality for
communicating with different wireless networks over different
wireless links using different wireless technologies and/or
protocols. Instead of wireless communication (or in addition
thereto), the EDs may communicate via wired communication channels
to a service provider or switch (not shown), and to the Internet
1650.
[0148] Although FIG. 16 illustrates one example of a communication
system, various changes may be made to FIG. 16. For example, the
communication system 1600 could include any number of EDs, base
stations, networks, or other components in any suitable
configuration.
[0149] FIGS. 17A and 17B illustrate example devices that may
implement the methods and teachings according to this disclosure.
In particular, FIG. 17A illustrates an example ED 1710, and FIG.
17B illustrates an example base station 1770. These components
could be used in the system 1300 or in any other suitable
system.
[0150] As shown in FIG. 17A, the ED 1710 includes at least one
processing unit 1700. The processing unit 1700 implements various
processing operations of the ED 1710. For example, the processing
unit 1700 could perform signal coding, data processing, power
control, input/output processing, or any other functionality
enabling the ED 1710 to operate in the system 1600. The processing
unit 1700 also supports the methods and teachings described in more
detail above. Each processing unit 1700 includes any suitable
processing or computing device configured to perform one or more
operations. Each processing unit 1700 could, for example, include a
microprocessor, microcontroller, digital signal processor, field
programmable gate array, or application specific integrated
circuit.
[0151] The ED 1710 also includes at least one transceiver 1702. The
transceiver 1702 is configured to modulate data or other content
for transmission by at least one antenna or NIC (Network Interface
Controller) 1704. The transceiver 1702 is also configured to
demodulate data or other content received by the at least one
antenna 1704. Each transceiver 1702 includes any suitable structure
for generating signals for wireless or wired transmission and/or
processing signals received wirelessly or by wire. Each antenna
1704 includes any suitable structure for transmitting and/or
receiving wireless or wired signals. One or multiple transceivers
1702 could be used in the ED 1710, and one or multiple antennas
1704 could be used in the ED 1710. Although shown as a single
functional unit, a transceiver 1702 could also be implemented using
at least one transmitter and at least one separate receiver.
[0152] The ED 1710 further includes one or more input/output
devices 1706 or interfaces (such as a wired interface to the
Internet 1650). The input/output devices 1706 facilitate
interaction with a user or other devices (network communications)
in the network. Each input/output device 1706 includes any suitable
structure for providing information to or receiving/providing
information from a user, such as a speaker, microphone, keypad,
keyboard, display, or touch screen, including network interface
communications.
[0153] In addition, the ED 1710 includes at least one memory 1708.
The memory 1708 stores instructions and data used, generated, or
collected by the ED 1710. For example, the memory 1708 could store
software or firmware instructions executed by the processing
unit(s) 1700 and data used to reduce or eliminate interference in
incoming signals. Each memory 1708 includes any suitable volatile
and/or non-volatile storage and retrieval device(s). Any suitable
type of memory may be used, such as random access memory (RAM),
read only memory (ROM), hard disk, optical disc, subscriber
identity module (SIM) card, memory stick, secure digital (SD)
memory card, and the like.
[0154] As shown in FIG. 17B, the base station 1770 includes at
least one processing unit 1750, at least one transceiver 1752,
which includes functionality for a transmitter and a receiver, one
or more antennas 1756, at least one memory 1758, and one or more
input/output devices or interfaces 1766. A scheduler, which would
be understood by one skilled in the art, is coupled to the
processing unit 1750. The scheduler could be included within or
operated separately from the base station 1770. The processing unit
1750 implements various processing operations of the base station
1770, such as signal coding, data processing, power control,
input/output processing, or any other functionality. The processing
unit 1750 can also support the methods and teachings described in
more detail above. Each processing unit 1750 includes any suitable
processing or computing device configured to perform one or more
operations. Each processing unit 1750 could, for example, include a
microprocessor, microcontroller, digital signal processor, field
programmable gate array, or application specific integrated
circuit.
[0155] Each transceiver 1752 includes any suitable structure for
generating signals for wireless or wired transmission to one or
more EDs or other devices. Each transceiver 1752 further includes
any suitable structure for processing signals received wirelessly
or by wire from one or more EDs or other devices. Although shown
combined as a transceiver 1752, a transmitter and a receiver could
be separate components. Each antenna 1756 includes any suitable
structure for transmitting and/or receiving wireless or wired
signals. While a common antenna 1756 is shown here as being coupled
to the transceiver 1752, one or more antennas 1756 could be coupled
to the transceiver(s) 1752, allowing separate antennas 1756 to be
coupled to the transmitter and the receiver if equipped as separate
components. Each memory 1758 includes any suitable volatile and/or
non-volatile storage and retrieval device(s). Each input/output
device 1766 facilitates interaction with a user or other devices
(network communications) in the network. Each input/output device
1766 includes any suitable structure for providing information to
or receiving/providing information from a user, including network
interface communications.
[0156] FIG. 18 is a block diagram of a computing system 1800 that
may be used for implementing the devices and methods disclosed
herein. For example, the computing system can be any entity of UE,
access network (AN), mobility management (MM), session management
(SM), user plane gateway (UPGW), and/or access stratum (AS).
Specific devices may utilize all of the components shown or only a
subset of the components, and levels of integration may vary from
device to device. Furthermore, a device may contain multiple
instances of a component, such as multiple processing units,
processors, memories, transmitters, receivers, etc. The computing
system 1800 includes a processing unit 1802. The processing unit
includes a central processing unit (CPU) 1814, memory 1808, and may
further include a mass storage device 1804, a video adapter 1810,
and an I/O interface 1812 connected to a bus 1820.
[0157] The bus 1820 may be one or more of any type of several bus
architectures including a memory bus or memory controller, a
peripheral bus, or a video bus. The CPU 1814 may comprise any type
of electronic data processor. The memory 1808 may comprise any type
of non-transitory system memory such as static random access memory
(SRAM), dynamic random access memory (DRAM), synchronous DRAM
(SDRAM), read-only memory (ROM), or a combination thereof. In an
embodiment, the memory 1808 may include ROM for use at boot-up, and
DRAM for program and data storage for use while executing
programs.
[0158] The mass storage 1804 may comprise any type of
non-transitory storage device configured to store data, programs,
and other information and to make the data, programs, and other
information accessible via the bus 1820. The mass storage 1804 may
comprise, for example, one or more of a solid state drive, hard
disk drive, a magnetic disk drive, or an optical disk drive.
[0159] The video adapter 1810 and the I/O interface 1812 provide
interfaces to couple external input and output devices to the
processing unit 1802. As illustrated, examples of input and output
devices include a display 1818 coupled to the video adapter 1810
and a mouse/keyboard/printer 1816 coupled to the I/O interface
1812. Other devices may be coupled to the processing unit 1802, and
additional or fewer interface cards may be utilized. For example, a
serial interface such as Universal Serial Bus (USB) (not shown) may
be used to provide an interface for an external device.
[0160] The processing unit 1802 also includes one or more network
interfaces 1806, which may comprise wired links, such as an
Ethernet cable, and/or wireless links to access nodes or different
networks. The network interfaces 1806 allow the processing unit
1802 to communicate with remote units via the networks. For
example, the network interfaces 1806 may provide wireless
communication via one or more transmitters/transmit antennas and
one or more receivers/receive antennas. In an embodiment, the
processing unit 1802 is coupled to a local-area network 1822 or a
wide-area network for data processing and communications with
remote devices, such as other processing units, the Internet, or
remote storage facilities.
[0161] It should be appreciated that one or more steps of the
embodiment methods provided herein may be performed by
corresponding units or modules. For example, a signal may be
transmitted by a transmitting unit or a transmitting module. A
signal may be received by a receiving unit or a receiving module. A
signal may be processed by a processing unit or a processing
module. Other steps may be performed by a providing unit/module, a
selecting unit/module, and/or a signaling unit/module. The
respective units/modules may be hardware, software, or a
combination thereof. For instance, one or more of the units/modules
may be an integrated circuit, such as field programmable gate
arrays (FPGAs) or application-specific integrated circuits
(ASICs).
[0162] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the disclosure as defined by the
appended claims.
* * * * *