U.S. patent application number 17/037458 was filed with the patent office on 2021-01-14 for random access collision reduction based on multiple uplink grants.
The applicant listed for this patent is QUALCOMM Incorporation. Invention is credited to Ravi Agarwal, Gavin Bernard Horn, Tingfang Ji, Tao Luo, Joseph Binamira Soriaga.
Application Number | 20210014904 17/037458 |
Document ID | / |
Family ID | 1000005120745 |
Filed Date | 2021-01-14 |
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United States Patent
Application |
20210014904 |
Kind Code |
A1 |
Agarwal; Ravi ; et
al. |
January 14, 2021 |
RANDOM ACCESS COLLISION REDUCTION BASED ON MULTIPLE UPLINK
GRANTS
Abstract
Techniques are described for wireless communication. A method
for wireless communication at a network access device may include
receiving a random access preamble; identifying a quantity of
uplink grants to associate with the random access preamble, the
identified quantity of uplink grants including at least one uplink
grant associated with at least one transmission resource, the
identified quantity of uplink grants based at least in part on a
time-variable parameter; and transmitting a random access response
message including the identified quantity of uplink grants.
Inventors: |
Agarwal; Ravi; (San Diego,
CA) ; Horn; Gavin Bernard; (La Jolla, CA) ;
Ji; Tingfang; (San Diego, CA) ; Soriaga; Joseph
Binamira; (San Diego, CA) ; Luo; Tao; (San
Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporation |
San Diego |
CA |
US |
|
|
Family ID: |
1000005120745 |
Appl. No.: |
17/037458 |
Filed: |
September 29, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15474133 |
Mar 30, 2017 |
10827529 |
|
|
17037458 |
|
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|
62354548 |
Jun 24, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/14 20130101;
H04W 72/085 20130101; H04W 72/1294 20130101; H04W 74/0833 20130101;
H04W 88/02 20130101 |
International
Class: |
H04W 74/08 20060101
H04W074/08; H04W 72/08 20060101 H04W072/08; H04W 72/14 20060101
H04W072/14 |
Claims
1. A method for wireless communication at a network access device,
the method comprising: receiving a random access preamble;
identifying a quantity of uplink grants to associate with the
random access preamble, the identified quantity of uplink grants
including at least one uplink grant associated with at least one
transmission resource, the identified quantity of uplink grants
based at least in part on a time-variable parameter; and
transmitting a random access response message including the
identified quantity of uplink grants.
2. The method of claim 1, wherein the quantity of uplink grants is
identified based at least in part on: a network load, or an
estimate of a number of collisions between transmissions of the
random access preamble by different user equipments (UEs), or an
estimate of a quantity of collisions between transmissions by
different UEs using a same uplink grant included in the random
access response message, or a quantity of channel elements in a
receiver of the network access device, or a quantity of available
transmission resources, or a time of receipt of the random access
preamble, or a combination thereof.
3. The method of claim 1, wherein the identified quantity of uplink
grants comprises of one uplink grant.
4. The method of claim 1, wherein the identified quantity of uplink
grants comprises a plurality of uplink grants.
5. The method of claim 1, further comprising: receiving a
transmission, from a user equipment (UE), on a transmission
resource associated with an uplink grant of the random access
response message.
6. The method of claim 5, further comprising: identifying, based at
least in part on the transmission resource on which the
transmission is received, at least one of: a feature set supported
by the UE, or a channel bandwidth supported by the UE, or an amount
of data in a transmit buffer of the UE, or a service used by the
UE, or a service requirement of the UE, or a QoS requirement of the
UE, or an access priority of the UE, or different slices, or a
combination thereof.
7. An apparatus for wireless communication at a network access
device, comprising: a processor; memory coupled with the processor;
and instructions stored in the memory and operable, when executed
by the processor, to cause the apparatus to: receive a random
access preamble; identify a quantity of uplink grants to associate
with the random access preamble, the identified quantity of uplink
grants including at least one uplink grant associated with at least
one transmission resource, the identified quantity of uplink grants
based at least in part on a time-variable parameter; and transmit a
random access response message including the identified quantity of
uplink grants.
8. The apparatus of claim 7, wherein the quantity of uplink grants
is identified based at least in part on: a network load, or an
estimate of a number of collisions between transmissions of the
random access preamble by different user equipments (UEs), or an
estimate of a quantity of collisions between transmissions by
different UEs using a same uplink grant included in the random
access response message, or a number of channel elements in a
receiver of the network access device, or a number of available
transmission resources, or a time of receipt of the random access
preamble, or a combination thereof.
9. The apparatus of claim 7, wherein the identified quantity of
uplink grants comprises of one uplink grant.
10. The apparatus of claim 7, wherein the identified quantity of
uplink grants comprises a plurality of uplink grants.
11. The apparatus of claim 7, wherein the instructions are
operable, when executed by the processor, to cause the apparatus
to: receive a transmission, from a user equipment (UE), on a
transmission resource associated with an uplink grant of the random
access response message.
12. The apparatus of claim 11, wherein the instructions are
operable, when executed by the processor, to cause the apparatus
to: identify, based at least in part on the transmission resource
on which the transmission is received, at least one of: a feature
set supported by the UE, or a channel bandwidth supported by the
UE, or an amount of data in a transmit buffer of the UE, or a
service used by the UE, or a service requirement of the UE, or a
QoS requirement of the UE, or an access priority of the UE, or
different slices, or a combination thereof.
13. An apparatus for wireless communication at a network access
device, comprising: means for receiving a random access preamble;
means for identifying a quantity of uplink grants to associate with
the random access preamble, the identified quantity of uplink
grants including at least one uplink grant associated with at least
one transmission resource, the identified quantity of uplink grants
based at least in part on a time-variable parameter; and means for
transmitting a random access response message including the
identified quantity of uplink grants.
14. The apparatus of claim 13, wherein the quantity of uplink
grants is identified based at least in part on: a network load, or
an estimate of a number of collisions between transmissions of the
random access preamble by different user equipments (UEs), or an
estimate of a quantity of collisions between transmissions by
different UEs using a same uplink grant included in the random
access response message, or a number of channel elements in a
receiver of the network access device, or a number of available
transmission resources, or a time of receipt of the random access
preamble, or a combination thereof.
15. The apparatus of claim 13, wherein the identified quantity of
uplink grants comprises of one uplink grant.
16. The apparatus of claim 13, wherein the identified quantity of
uplink grants comprises a plurality of uplink grants.
17. The apparatus of claim 13, further comprising: means for
receiving a transmission, from a user equipment (UE), on a
transmission resource associated with an uplink grant of the random
access response message.
18. The apparatus of claim 17, further comprising: means for
identifying, based at least in part on the transmission resource on
which the transmission is received, at least one of: a feature set
supported by the UE, or a channel bandwidth supported by the UE, or
an amount of data in a transmit buffer of the UE, or a service used
by the UE, or a service requirement of the UE, or a QoS requirement
of the UE, or an access priority of the UE, or different slices, or
a combination thereof.
19. A non-transitory computer-readable medium storing code for
wireless communication at a network access device, the code
comprising instructions executable by a processor to: receive a
random access preamble; identify a quantity of uplink grants to
associate with the random access preamble, the identified quantity
of uplink grants including at least one uplink grant associated
with at least one transmission resource, the identified quantity of
uplink grants based at least in part on a time-variable parameter;
and transmit a random access response message including the
identified quantity of uplink grants.
20. The non-transitory computer-readable medium of claim 19,
wherein the quantity of uplink grants is identified based at least
in part on: a network load, or an estimate of a number of
collisions between transmissions of the random access preamble by
different user equipments (UEs), or an estimate of a quantity of
collisions between transmissions by different UEs using a same
uplink grant included in the random access response message, or a
number of channel elements in a receiver of the network access
device, or a number of available transmission resources, or a time
of receipt of the random access preamble, or a combination
thereof.
21. The non-transitory computer-readable medium of claim 19,
wherein the identified quantity of uplink grants comprises of one
uplink grant.
22. The non-transitory computer-readable medium of claim 19,
wherein the identified quantity of uplink grants comprises a
plurality of uplink grants.
23. The non-transitory computer-readable medium of claim 19,
wherein the instructions are further executable by the processor
to: receiving a transmission, from a user equipment (UE), on a
transmission resource associated with an uplink grant of the random
access response message.
24. The non-transitory computer-readable medium of claim 23,
wherein the instructions are further executable by the processor
to: identify, based at least in part on the transmission resource
on which the transmission is received, at least one of: a feature
set supported by the UE, or a channel bandwidth supported by the
UE, or an amount of data in a transmit buffer of the UE, or a
service used by the UE, or a service requirement of the UE, or a
QoS requirement of the UE, or an access priority of the UE, or
different slices, or a combination thereof.
Description
CROSS REFERENCES
[0001] The present application for patent is a Divisional of U.S.
patent application Ser. No. 15/474,133 by Agarwal et al., entitled
"RANDOM ACCESS COLLISION REDUCTION BASED ON MULTIPLE UPLINK GRANTS"
filed Mar. 30, 2017, which claims priority to U.S. Provisional
Patent Application No. 62/354,548 by Agarwal et al., entitled
"RANDOM ACCESS COLLISION REDUCTION BASED ON MULTIPLE UPLINK
GRANTS," filed Jun. 24, 2016, each of which is assigned to the
assignee hereof, and each of which is hereby expressly incorporated
by reference herein in its entirety.
INTRODUCTION
[0002] The present disclosure, for example, relates to wireless
communication systems, and more particularly to random access
collision reduction based on multiple uplink grants.
[0003] Wireless communication 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 multiple-access systems 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 code-division multiple access
(CDMA) systems, time-division multiple access (TDMA) systems,
frequency-division multiple access (FDMA) systems, and orthogonal
frequency-division multiple access (OFDMA) systems.
[0004] In some examples, a wireless multiple-access communication
system may include a number of base stations, each simultaneously
supporting communication for multiple communication devices,
otherwise known as user equipments (UEs). In a Long-Term Evolution
(LTE) or LTE-Advanced (LTE-A) network, a set of one or more base
stations may define an eNodeB (eNB). In other examples (e.g., in a
next generation or 5G network), a wireless multiple access
communication system may include a number of smart radio heads
(radio heads (RHs)) in communication with a number of access node
controllers (ANCs), where a set of one or more radio heads, in
communication with an ANC, may define an eNB. A base station or
radio head may communicate with a set of UEs on downlink channels
(e.g., for transmissions from a base station or radio head to a UE)
and uplink channels (e.g., for transmissions from a UE to a base
station or radio head).
[0005] In some examples, a UE may perform a random access procedure
with a network access device (e.g., a base station, an RH, an ANC,
or an eNB). Other UEs may additionally or alternatively perform a
random access procedure. When two or more UEs perform a random
access procedure based on the same random access preamble,
transmissions of the UEs may collide, and none of the UEs may
perform the random access procedure successfully or access a
network via the network access device.
SUMMARY
[0006] A method for wireless communication at a UE is described.
The method may include transmitting a random access preamble,
receiving a random access response message that includes a
plurality of uplink grants associated with the random access
preamble, selecting an uplink grant from the plurality of uplink
grants, and transmitting using the selected uplink grant. Each
uplink grant in the plurality of uplink grants may be associated
with a different transmission resource.
[0007] An apparatus for wireless communication at a UE is
described. The apparatus may include means for transmitting a
random access preamble, means for receiving a random access
response message that includes a plurality of uplink grants
associated with the random access preamble, means for selecting an
uplink grant from the plurality of uplink grants, and means for
transmitting using the selected uplink grant. Each uplink grant in
the plurality of uplink grants may be associated with a different
transmission resource.
[0008] Another apparatus for wireless communication at a UE is
described. The apparatus may include a processor, memory in
electronic communication with the processor, and instructions
stored in the memory. The instructions may be operable to cause the
processor to transmit a random access preamble, receive a random
access response message that includes a plurality of uplink grants
associated with the random access preamble, select an uplink grant
from the plurality of uplink grants, and transmit using the
selected uplink grant. Each uplink grant in the plurality of uplink
grants may be associated with a different transmission
resource.
[0009] A non-transitory computer-readable medium for wireless
communication at a UE is described. The non-transitory
computer-readable medium may include instructions operable to cause
a processor to transmit a random access preamble, receive a random
access response message that includes a plurality of uplink grants
associated with the random access preamble, select an uplink grant
from the plurality of uplink grants, and transmit using the
selected uplink grant. Each uplink grant in the plurality of uplink
grants may be associated with a different transmission
resource.
[0010] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE identifiers (IDs), or combinations thereof.
[0011] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, selecting
an uplink grant may include randomly selecting an uplink grant from
the plurality of uplink grants.
[0012] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, at least
two of the uplink grants may be associated with different feature
sets, and the selected uplink grant may be selected based at least
in part on a feature set supported by the UE.
[0013] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, at least
two of the uplink grants may be associated with different maximum
channel bandwidths, and the selected uplink grant may be selected
based at least in part on a maximum channel bandwidth supported by
the UE.
[0014] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, at least
two of the uplink grants may be associated with different payload
sizes, and the selected uplink grant may be selected based at least
in part on an amount of data in a transmit buffer of the UE.
[0015] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, at least
two of the uplink grants may be associated with at least one of
different sets of services, or different service requirements, or
different quality of service (QoS) profiles, or different access
priorities, or different slices, or combinations thereof, and
wherein the selected uplink grant is selected based at least in
part on a service used by the UE, or a service requirement of the
UE, or a QoS requirement of the UE, or an access priority of the
UE, or different slices, or combinations thereof.
[0016] A method for wireless communication at a network access
device is described. The method may include receiving a random
access preamble, and transmitting a random access response message
that includes a plurality of uplink grants associated with the
random access preamble. Each uplink grant in the plurality of
uplink grants may be associated with a different transmission
resource.
[0017] An apparatus for wireless communication at a network access
device is described. The apparatus may include means for receiving
a random access preamble, and means for transmitting a random
access response message that includes a plurality of uplink grants
associated with the random access preamble. Each uplink grant in
the plurality of uplink grants may be associated with a different
transmission resource.
[0018] Another apparatus for wireless communication at a network
access device is described. The apparatus may include a processor,
memory in electronic communication with the processor, and
instructions stored in the memory. The instructions may be operable
to cause the processor to receive a random access preamble, and
transmit a random access response message that includes a plurality
of uplink grants associated with the random access preamble. Each
uplink grant in the plurality of uplink grants may be associated
with a different transmission resource.
[0019] A non-transitory computer-readable medium for wireless
communication at a network access device is described. The
non-transitory computer-readable medium may include instructions
operable to cause a processor to receive a random access preamble,
and transmit a random access response message that includes a
plurality of uplink grants associated with the random access
preamble. Each uplink grant in the plurality of uplink grants may
be associated with a different transmission resource.
[0020] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof.
[0021] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for receiving
transmissions from at least two UEs on transmission resources
associated with at least two uplink grants in the plurality of
uplink grants.
[0022] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for identifying a
number of uplink grants in the plurality of uplink grants based at
least in part on a network load, or an estimate of a number of
collisions between transmissions of the random access preamble by
different UEs, or an estimate of a number of collisions between
transmissions by different UEs using a same uplink grant included
in the random access response message, or a number of channel
elements in a receiver of the network access device, or a number of
available transmission resources, or a time of receipt of the
random access preamble, or combinations thereof.
[0023] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for associating at
least two of the uplink grants with different feature sets, or
different maximum channel bandwidths, or different payload sizes,
or different sets of services, or different service requirements,
or different QoS profiles, or different access priorities, or
different slices, or combinations thereof.
[0024] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for receiving a
transmission, from a UE, on a transmission resource associated with
an uplink grant in the plurality of uplink grants. The method,
apparatus, and non-transitory computer-readable medium may further
include processes, features, means, or instructions for
identifying, based at least in part on the transmission resource on
which the transmission is received, at least one of a feature set
supported by the UE, or a channel bandwidth supported by the UE, or
an amount of data in a transmit buffer of the UE, or a service used
by the UE, or a service requirement of the UE, or a QoS requirement
of the UE, or an access priority of the UE, or different slices, or
combinations thereof.
[0025] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the
identified number of uplink grants may comprise of one uplink
grant. In other examples, the identified number of uplink grants
may include a plurality of uplink grants.
[0026] Another method for wireless communication at a network
access device is described. The method may include receiving a
random access preamble, identifying a number of uplink grants to
associate with the random access preamble, and transmitting a
random access response message including the identified number of
uplink grants. The identified number of uplink grants may include
at least one uplink grant associated with at least one transmission
resource. The identified number of uplink grants may be based at
least in part on a time-variable parameter.
[0027] Another apparatus for wireless communication at a network
access device is described. The apparatus may include means for
receiving a random access preamble, means for identifying a number
of uplink grants to associate with the random access preamble, and
means for transmitting a random access response message including
the identified number of uplink grants. The identified number of
uplink grants may include at least one uplink grant associated with
at least one transmission resource. The identified number of uplink
grants may be based at least in part on a time-variable
parameter.
[0028] Another apparatus for wireless communication at a network
access device is described. The apparatus may include a processor,
memory in electronic communication with the processor, and
instructions stored in the memory. The instructions may be operable
to cause the processor to receive a random access preamble,
identify a number of uplink grants to associate with the random
access preamble, and transmit a random access response message
including the identified number of uplink grants. The identified
number of uplink grants may include at least one uplink grant
associated with at least one transmission resource. The identified
number of uplink grants may be based at least in part on a
time-variable parameter.
[0029] Another non-transitory computer-readable medium for wireless
communication at a network access device is described. The
non-transitory computer-readable medium may include instructions
operable to cause a processor to receive a random access preamble,
identify a number of uplink grants to associate with the random
access preamble, and transmit a random access response message
including the identified number of uplink grants. The identified
number of uplink grants may include at least one uplink grant
associated with at least one transmission resource. The identified
number of uplink grants may be based at least in part on a
time-variable parameter.
[0030] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the number
of uplink grants may be identified based at least in part on a
network load, or an estimate of a number of collisions between
transmissions of the random access preamble by different UEs, or an
estimate of a number of collisions between transmissions by
different UEs using a same uplink grant included in the random
access response message, or a number of channel elements in a
receiver of the network access device, or a number of available
transmission resources, or a time of receipt of the random access
preamble, or combinations thereof.
[0031] In some examples of the method, apparatus, and
non-transitory computer-readable medium described above, the
identified number of uplink grants may comprise of one uplink
grant. In other examples, the identified number of uplink grants
may include a plurality of uplink grants.
[0032] Some examples of the method, apparatus, and non-transitory
computer-readable medium described above may further include
processes, features, means, or instructions for receiving a
transmission, from a UE, on a transmission resource associated with
an uplink grant in the plurality of uplink grants. The method,
apparatus, and non-transitory computer-readable medium may further
include processes, features, means, or instructions for
identifying, based at least in part on the transmission resource on
which the transmission is received, at least one of a feature set
supported by the UE, or a channel bandwidth supported by the UE, or
an amount of data in a transmit buffer of the UE, or a service used
by the UE, or a service requirement of the UE, or a QoS requirement
of the UE, or an access priority of the UE, or different slices, or
combinations thereof.
[0033] The foregoing has outlined rather broadly the techniques and
technical advantages of examples according to the disclosure in
order that the detailed description that follows may be better
understood. Additional techniques and advantages will be described
hereinafter. The conception and specific examples disclosed may be
readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
disclosure. Such equivalent constructions do not depart from the
scope of the appended claims. Characteristics of the concepts
disclosed herein, both their organization and method of operation,
together with associated advantages will be better understood from
the following description when considered in connection with the
accompanying figures. Each of the figures is provided for the
purpose of illustration and description, and not as a definition of
the limits of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] A further understanding of the nature and advantages of the
present disclosure may be realized by reference to the following
drawings. In the appended figures, similar components or functions
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.
[0035] FIG. 1 illustrates an example of a wireless communication
system, in accordance with one or more aspects of the present
disclosure;
[0036] FIG. 2 shows a message flow between a UE and a network
access device during performance of a contention-based random
access procedure, in accordance with one or more aspects of the
present disclosure;
[0037] FIG. 3 shows examples of random access preamble selections
and uplink grant selections made by a plurality of UEs when
performing respective random access procedures at the same time, in
accordance with one or more aspects of the present disclosure;
[0038] FIG. 4 shows examples of random access preamble selections
and uplink grant selections made by a plurality of UEs when
performing respective random access procedures at the same time, in
accordance with one or more aspects of the present disclosure;
[0039] FIG. 5 shows a block diagram of an apparatus for use in
wireless communication, in accordance with one or more aspects of
the present disclosure;
[0040] FIG. 6 shows a block diagram of a wireless communication
manager for use in wireless communication, in accordance with one
or more aspects of the present disclosure;
[0041] FIG. 7 shows a block diagram of an apparatus for use in
wireless communication, in accordance with one or more aspects of
the present disclosure;
[0042] FIG. 8 shows a block diagram of a wireless communication
manager for use in wireless communication, in accordance with one
or more aspects of the present disclosure;
[0043] FIG. 9 shows a block diagram of a UE for use in wireless
communication, in accordance with one or more aspects of the
present disclosure;
[0044] FIG. 10 shows a block diagram of a network access device for
use in wireless communication, in accordance with one or more
aspects of the present disclosure;
[0045] FIG. 11 is a flow chart illustrating an example of a method
for wireless communication at a UE, in accordance with one or more
aspects of the present disclosure;
[0046] FIG. 12 is a flow chart illustrating an example of a method
for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure;
[0047] FIG. 13 is a flow chart illustrating an example of a method
for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure;
and
[0048] FIG. 14 is a flow chart illustrating an example of a method
for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure.
DETAILED DESCRIPTION
[0049] The present disclosure describes techniques for reducing
random access collisions between two or more UEs. At times (e.g.,
when initially accessing a network, or during a handover), a UE may
perform a random access procedure with a network access device.
Some random access procedures (e.g., random access procedures
performed when initially accessing a network) may be
contention-based, meaning that two or more UEs may perform a random
access procedure at the same time and contend for the same random
access resources. When each UE performs its random access procedure
using different resources, the random access procedures performed
by the UEs may all be performed successfully (e.g., when performing
a random access procedure to initially access a network, a UE may
succeed in obtaining access to the network). However, in some
instances, two or more UEs may perform their random access
procedures using the same resource(s), and in these instances, the
random access procedures performed by one or more (or all) of the
UEs may not complete successfully. The UE(s) for which random
access procedures do not complete successfully may have to perform
their random access procedure again. Failure to complete a random
access procedure successfully may result in inefficiency and delay
(e.g., a delay in obtaining access to a network).
[0050] In some contention-based random access procedures, a UE may
randomly select a random access preamble from a set of
predetermined preamble sequences and transmit a message including
the random access preamble to a network access device. When a
random access preamble is randomly selected by a UE, it is possible
that two or more UEs may select the same random access
preamble.
[0051] Upon receiving a message including a random access preamble,
a network access device may be unaware of whether one, two, or more
UEs transmitted the same message including the same random access
preamble (e.g., because all of the UEs may transmit the same random
access preamble on the same resource(s)). In response to receiving
a random access preamble, a network access device may transmit a
random access response message. The random access response message
may include an uplink grant that a UE may use to transmit a first
scheduled uplink transmission to the network access device.
Because, at the time the network access device transmits the random
access response message, the network access device does not know
the identity (or identities) of the UE or UEs that transmitted a
message including a random access preamble, the uplink grant may
not be specific to any particular UE, and any UE may use the uplink
grant to make a first scheduled uplink transmission to the network
access device. Thus, when two or more UEs transmit a message
including the same random access preamble, all of these UEs may
transmit a first scheduled uplink transmission using the same
uplink grant, resulting in contention. A network access device may
be unable to resolve such contention.
[0052] To reduce the probability of collisions between first
scheduled uplink transmissions of different UEs (i.e., different
UEs that transmit messages including the same random access
preamble at the same time), a network access device may transmit a
random access response message that includes a plurality of uplink
grants (e.g., N uplink grants, where N is an integer greater than
or equal to 2). Each uplink grant in the plurality of uplink grants
may be associated with a different transmission resource, such that
first scheduled uplink transmissions by different UEs using
different uplink grants will not collide. If UEs select uplink
grants at random, the probability that first scheduled uplink
transmissions of UEs performing random access procedures based on
the same random access preamble, at the same time, may be reduced
by a factor of N. Additionally or alternatively, a network access
device may transmit a random access response message that includes
one or more uplink grants, with the number of uplink grants that
are included in the random access response message being determined
based at least in part on a time-variable parameter. In some
examples, the time-variable parameter may be based on factors such
as a network load or an estimated number of random access
collisions. In this manner, measures may be taken to reduce random
access collisions at times when random access collisions are
believed to be more likely.
[0053] The following description provides examples, and is not
limiting of the scope, applicability, or examples set forth in the
claims. Changes may be made in the function and arrangement of
elements discussed without departing from the scope of the
disclosure. Various examples may omit, substitute, or add various
procedures or components as appropriate. For instance, the methods
described may be performed in an order different from that
described, and various operations may be added, omitted, or
combined. Additionally or alternatively, features described with
respect to some examples may be combined in other examples.
[0054] FIG. 1 illustrates an example of a wireless communication
system 100, in accordance with one or more aspects of the present
disclosure. The wireless communication system 100 may include
network access devices (e.g., base stations 105, gNodeBs (gNBs),
and/or radio heads (RHs)), UEs 115, and a core network 130. The
core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The base stations 105
may interface with the core network 130 through backhaul links 132
(e.g., S1, etc.) and may perform radio configuration and scheduling
for communication with the UEs 115, or may operate under the
control of a base station controller (not shown). In various
examples, the base stations 105 may communicate, either directly or
indirectly (e.g., through core network 130), with each other over
backhaul links 134 (e.g., X1, etc.), which may be wired or wireless
communication links. Wireless communication system 100 may support
synchronous or asynchronous operation.
[0055] The core network 130 may provide user authentication, access
authorization, tracking, IP connectivity, and other access,
routing, or mobility functions. At least some of the network access
devices (e.g., eNBs, gNBs) or ANCs may interface with the core
network 130 through backhaul links 132 (e.g., S1, etc.) and may
perform radio configuration and scheduling for communication with
the UEs 115. In various examples, the ANCs may communicate, either
directly or indirectly (e.g., through core network 130), with each
other over backhaul links 134 (e.g., X1, X2, etc.), which may be
wired or wireless communication links. A UE 115 may communicate
with the core network 130 through communication link 135. Each ANC
may additionally or alternatively communicate with a number of UEs
115 through a number of smart radio heads. In an alternative
configuration of the wireless communication system 100, the
functionality of an ANC may be provided by a radio head or
distributed across the radio heads of an eNB.
[0056] The base stations 105 may wirelessly communicate with the
UEs 115 via one or more base station antennas. Each of the base
stations 105 may provide communication coverage for a respective
geographic coverage area 110. In some examples, a base station 105
may be referred to as a base transceiver station, a radio base
station, an access point, a radio transceiver, a NodeB, an eNB, a
Home NodeB, a Home eNodeB, or some other suitable terminology. The
geographic coverage area 110 for a base station 105 may be divided
into sectors making up a portion of the coverage area (not shown).
The wireless communication system 100 may include base stations 105
of different types (e.g., macro or small cell base stations). There
may be overlapping geographic coverage areas 110 for different
technologies.
[0057] In some examples, the wireless communication system 100 may
include a new radio (i.e., 5G) network. In some examples, the
wireless communication system 100 may include an LTE/LTE-A network.
In LTE/LTE-A networks, the term eNB may be used to describe the
base stations 105. The wireless communication system 100 may be a
Heterogeneous LTE/LTE-A network in which different types of eNBs
provide coverage for various geographical regions. For example,
each eNB or base station 105 may provide communication coverage for
a macro cell, a small cell, or other types of cell. The term "cell"
is a 3GPP term that can be used to describe a base station, a radio
head, a carrier or component carrier associated with a base station
or a radio head, or a coverage area (e.g., sector, etc.) of a
carrier or base station, depending on context.
[0058] A macro cell may cover 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 a lower-powered base station, as compared with
a macro cell that may operate in the same or different (e.g.,
licensed, unlicensed, etc.) spectrums as macro cells. Small cells
may include pico cells, femto cells, and micro cells according to
various examples. A pico cell may cover a relatively smaller
geographic area and may allow unrestricted access by UEs with
service subscriptions with the network provider. A femto cell
additionally or alternatively may cover a relatively 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 (e.g.,
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).
[0059] The wireless communication system 100 may support
synchronous or asynchronous operation. For synchronous operation,
the base stations 105 may have similar frame timing, and
transmissions from different base stations 105 may be approximately
aligned in time. For asynchronous operation, the base stations 105
may have different frame timing, and transmissions from different
base stations 105 may not be aligned in time. The techniques
described herein may be used for either synchronous or asynchronous
operations.
[0060] The communication networks that may accommodate some of the
various disclosed examples may be packet-based networks 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
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 additionally or alternatively
use Hybrid ARQ (HARD) 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 the base stations 105 or core network 130 supporting radio
bearers for the user plane data. At the physical (PHY) layer, the
transport channels may be mapped to physical channels.
[0061] The UEs 115 may be dispersed throughout the wireless
communication system 100, and each UE 115 may be stationary or
mobile. A UE 115 may additionally or alternatively include or be
referred to by those skilled in the art as a mobile station, a
subscriber station, a mobile unit, a subscriber unit, a wireless
unit, a remote unit, a mobile device, a wireless device, a wireless
communication device, a remote device, a mobile subscriber station,
an access terminal, a mobile terminal, a wireless terminal, a
remote terminal, a handset, a user agent, a mobile client, a
client, or some other suitable terminology. A UE 115 may be a
cellular phone, a smart phone, a personal digital assistant (PDA),
a wireless modem, a wireless communication device, a handheld
device, a tablet computer, a laptop computer, a cordless phone, a
wireless local loop (WLL) station, etc. 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.
[0062] The communication links 125 shown in wireless communication
system 100 may include downlinks (DLs), from a base station 105 to
a UE 115, or uplinks (ULs), from a UE 115 to a base station 105.
The downlinks may also be called forward links, while the uplinks
may also be called reverse links.
[0063] In some examples, each communication link 125 may include
one or more carriers, where each carrier may be a signal made up of
multiple sub-carriers (e.g., waveform signals of different
frequencies) modulated according to the various radio technologies
described above. Each modulated signal may be transmitted on a
different sub-carrier and may carry control information (e.g.,
reference signals, control channels, etc.), overhead information,
user data, etc. The communication links 125 may transmit
bidirectional communications using a frequency domain duplexing
(FDD) operation (e.g., using paired spectrum resources) or a time
domain duplexing (TDD) operation (e.g., using unpaired spectrum
resources). Frame structures for FDD operation (e.g., frame
structure type 1) and TDD operation (e.g., frame structure type 2)
may be defined.
[0064] In some examples of the wireless communication system 100,
base stations 105, or UEs 115 may include multiple antennas for
employing antenna diversity schemes to improve communication
quality and reliability between base stations 105 and UEs 115.
Additionally or alternatively, base stations 105 or UEs 115 may
employ multiple-input, multiple-output (MIMO) techniques that may
take advantage of multi-path environments to transmit multiple
spatial layers carrying the same or different coded data.
[0065] The wireless communication system 100 may support operation
on multiple cells or carriers, a feature which may be referred to
as carrier aggregation (CA) or dual-connectivity operation. A
carrier may also be referred to as a component carrier (CC), a
layer, a channel, etc. The terms "carrier," "component carrier,"
"cell," and "channel" may be used interchangeably herein. Carrier
aggregation may be used with both FDD and TDD component
carriers.
[0066] In an LTE/LTE-A network, a UE 115 may be configured to
communicate using up to five CCs when operating in a carrier
aggregation mode or dual-connectivity mode. One or more of the CCs
may be configured as a DL CC, and one or more of the CCs may be
configured as an uplink (UL) CC. Additionally or alternatively, one
of the CCs allocated to a UE 115 may be configured as a primary CC
(PCC), and the remaining CCs allocated to the UE 115 may be
configured as secondary CCs (SCCs).
[0067] At times, a UE 115 may perform a random access procedure
with a network access device (e.g., a base station 105). A UE 115
may perform a random access procedure with a base station 105 of an
LTE/LTE-A network, for example, when initially accessing the
LTE/LTE-A network from an idle state (e.g., when performing initial
access from an RRC IDLE state), or when performing an RRC
Connection Re-establishment procedure, or in conjunction with a
handover procedure. The performance of a random access procedure
when initially accessing a LTE/LTE-A network from an idle state is
the most common type of random access procedure. A UE may
additionally or alternatively perform a random access procedure
with a network access device upon downlink data arrival when in an
RRC_CONNECTED state (e.g., when UL synchronization is
"non-synchronized"), or upon uplink data arrival when in an
RRC_CONNECTED state (e.g., when UL synchronization is
"non-synchronized," or when no Physical Uplink Control Channel
(PUCCH) resources are available for transmitting a SR). A UE may
additionally or alternatively perform a random access procedure
with a network access device for a positioning purpose when in an
RRC_CONNECTED state (e.g., when a timing advance is needed for UE
positioning). In some examples, a UE may perform a random access
procedure with a network access device in a CA or dual-connectivity
scenario.
[0068] Random access procedures may be contention-based or
non-contention-based. Contention-based random access procedures are
more common, and include random access procedures performed when
initially accessing a LTE/LTE-A network from an idle state.
Non-contention-based random access procedures include, for example,
random access procedures performed in conjunction with a handover
procedure. Techniques described in the present disclosure pertain
to a contention-based random access procedure.
[0069] In some examples, a UE 115 may include a wireless
communication manager 520. The wireless communication manager 520
may be used to transmit a random access preamble (e.g., to a base
station 105), receive a random access response message that
includes a plurality of uplink grants associated with the random
access preamble, select an uplink grant from the plurality of
uplink grants, and transmit using the selected uplink grant (e.g.,
transmit a first scheduled uplink transmission to the base station
105). Each uplink grant in the plurality of uplink grants may be
associated with a different transmission resource, so that
transmissions by multiple UEs 115 using multiple ones of the uplink
grants do not collide.
[0070] In some examples, a base station 105 may include a wireless
communication manager 720. The wireless communication manager 720
may be used to receive a random access preamble from one or more of
the UEs 115, and transmit a random access response message that
includes a plurality of uplink grants associated with the random
access preamble. Each uplink grant in the plurality of uplink
grants may be associated with a different transmission resource, so
that transmissions by multiple UEs 115 using multiple ones of the
uplink grants do not collide. In alternative examples, the wireless
communication manager 720 may be used to receive a random access
preamble from one or more of the UEs 115, identify a number of
uplink grants to associate with the random access preamble, and
transmit a random access response message including the identified
number of uplink grants. The identified number of uplink grants may
include a single uplink grant or a plurality of uplink grants, each
of which is associated with at least one transmission resource. The
identified number of uplink grants may be based at least in part on
a time-variable parameter, such as a network load, or an estimate
of a number of collisions between transmissions of the random
access preamble by different UEs, or an estimate of a number of
collisions between transmissions by different UEs using a same
uplink grant included in the random access response message, or a
number of channel elements in a receiver of the network access
device, or a number of available transmission resources, or a time
of receipt of the random access preamble, or combinations
thereof.
[0071] FIG. 2 shows a message flow 200 between a UE 115-a and a
network access device 205 during performance of a contention-based
random access procedure, in accordance with one or more aspects of
the present disclosure. The UE 115-a may be an example of aspects
of the UEs 115 described with reference to FIG. 1. The network
access device 205 may be an example of aspects of a base station
105 described with reference to FIG. 1, or an example of aspects of
an eNB, RH, ANC, or access point, for example.
[0072] The message flow 200 includes four messages, including a
first message (Msg1) transmitted by the UE 115-a to the network
access device 205 at 210, a second message (Msg2) transmitted by
the network access device 205 to the UE 115-a at 215, a third
message (Msg3) transmitted by the UE 115-a to the network access
device 205 at 220, and a fourth message (Msg4) transmitted by the
network access device 205 to the UE 115-a at 225.
[0073] At 210, a message including a random access preamble may be
transmitted on a random access channel (RACH) of an uplink. In some
examples, the random access preamble may be selected from a
plurality of preamble sequences, such as a set of 64 preamble
sequences associated with a cell. The UE 115-a may identify the
plurality of preamble sequences from system information (SI)
broadcast by the network access device 205. In some examples, the
preamble sequences may be divided into two or more subsets, and the
UE 115-a may select a random access preamble from a predetermined
or derived one of the sub sets.
[0074] At 215, and in response to detecting the random access
preamble transmitted at 210, the network access device 205 may
transmit a random access response (RAR) message. In some examples,
the RAR message may be transmitted on a downlink shared channel
(DL-SCH), using a random access radio network temporary identifier
(RA-RNTI) as a physical ID. If the network access device 205 does
not detect the random access preamble transmitted at 210, the
network access device 205 will not transmit a RAR message at
215.
[0075] The RAR message may include, for example, an index
corresponding to the detected random access preamble (e.g., an
index of a detected preamble sequence), an uplink grant (e.g., a
grant of transmission resources on an uplink shared channel
(UL-SCH), an indication of a timing advance, or a temporary cell
RNTI (TC-RNTI). In some examples, multiple RAR messages (e.g., RAR
messages corresponding to different random access preambles
received from different UEs) may be included in a single payload
transmitted at 215.
[0076] Upon receiving one or more RAR messages transmitted at 215,
the UE 115-a may identify a RAR message intended for the UE 115-a
based at least in part on detecting, in a RAR message, an index
corresponding to the random access preamble transmitted by the UE
115-a at 210. When multiple UEs transmit the same random access
preamble on the same transmission resources at 210, all of the UEs
may use the same RA-RNTI and identify the same RAR message
(transmitted at 215) as intended for itself.
[0077] At 220, the UE 115-a may transmit a first scheduled UL
transmission using the transmission resources associated with an
uplink grant included in a RAR message intended for the UE 115-a.
The first scheduled UL transmission may include an RRC Connection
Request message and include an identifier of the UE 115-a (i.e., a
UE identifier). The first scheduled UL transmission may be
scrambled using a TC-RNTI included in the RAR message intended for
the UE 115-a. Upon transmitting a first scheduled UL transmission
at 220, the UE 115-a may start a contention resolution timer.
[0078] When multiple UEs (i.e., two or more UEs) transmit the same
random access preamble on the same transmission resources at 210,
each of the UEs may transmit a first scheduled UL transmission on
the same transmission resources at 220 and the transmissions made
by all of the UEs will collide. Additionally or alternatively, all
of the UEs will receive and interpret the same feedback for their
transmissions at 220 (e.g., a HARQ Acknowledgement (ACK) or
Non-acknowledgement (NACK) received on a Physical Hybrid-ARQ
Indicator Channel (PHICH) or Physical Downlink Control Channel
(PDCCH) and associated with the TC-RNTI included in the RAR message
transmitted at 215 for the UEs), and will assume the feedback
corresponds to their transmission at 220. When the feedback is a
HARQ NACK (which is likely), each of the UEs will perform a
retransmission of its transmission made at 220, on the same
retransmission resources, leading to a collision between the
retransmissions.
[0079] At 225, and in response to decoding the scheduled UL
transmission of the UE 115-a at 220, the network access device 205
may transmit a contention resolution message to the UE 115-a. In
some examples, the contention resolution message may be transmitted
on the DL-SCH, and may be scrambled using the same TC-RNTI used to
scramble the scheduled UL transmission transmitted at 220. However,
if the network access device 205 cannot decode the scheduled UL
transmission transmitted at 220, the network access device 205 will
not transmit a contention resolution message at 225, and the
contention resolution timer started by the UE 115-a may expire,
thereby causing the UE 115-a to initiate a new random access
procedure.
[0080] The contention resolution message may include, for example,
the UE identifier received in the scheduled UL transmission
transmitted at 225. The contention resolution message may
additionally or alternatively include other information.
[0081] When multiple UEs make a first scheduled UL transmission at
220, and the network access device 205 is able to decode one of the
scheduled UL transmissions despite the interference from other
scheduled UL transmissions, the network access device 205 may
transmit a contention resolution message (at 225) that may be
decoded by each of the UEs. When the contention resolution message
includes the UE's UE identifier, the UE may pass the contention
resolution message to upper layers its protocol stack, assume that
its contention-based random access procedure was successful (or
that collision resolution was successful), and set its cell RNTI
(C-RNTI) to TC-RNTI. When the contention resolution message does
not include the UE's UE identifier, or when a UE does not receive
the contention resolution message before its contention resolution
timer expires, the UE may assume that its contention-based random
access procedure failed (or that collision resolution failed) and
may perform another contention-based random access procedure.
[0082] Following the successful performance of a contention-based
random access procedure, the UE 115-a and network access device 205
may communicate via downlink transmissions and/or uplink
transmissions beginning at 230.
[0083] When multiple UEs perform the random access procedure
described with reference to FIG. 2 and transmit the same random
access preamble on the same transmission resource at 210, the UEs
will transmit scheduled UL transmissions (at 220) that collide and
interfere with each other. In some examples, the probability of a
collision occurring at 220 may be reduced by increasing the number
of preamble sequences from which a UE may select a random access
preamble for transmission at 210. However, increasing the numbers
of preamble sequences increases the number of random access
preambles that the network access device 205 has to monitor for at
215, which can increase both the cost and power consumption of a
receiver of the network access device 205.
[0084] In some examples, the probability of a collision occurring
at 220 may be reduced by allocating different access classes to
different UEs, and allocating the different access classes
different time slots of random access transmission resources. In
this manner, the random access transmission load is distributed
over a longer time period. However, this approach can increase the
latency associated with random access.
[0085] In some examples, the probability of a collision occurring
at 220 may be reduced by allocating additional transmission
resources (e.g., unoccupied or available transmission resources)
for a UE to transmit a first scheduled UL transmission. For
example, in response to detecting a random access preamble, the
network access device 205 (or another network node to which the
network access device 205 is connected) may identify N uplink
grants associated with N different transmission resources, and
transmit a random access response message (at 215) including the N
identified uplink grants. In some examples, the N uplink grants may
include a predetermined or semi-static plurality of (e.g., two or
more) uplink grants. In some examples, the N uplink grants may be
identified periodically, or upon the occurrence of predetermined
events, or for each random access preamble received by the network
access device 205. In some examples, the N uplink grants may
include one uplink grant or a plurality of uplink grants. In some
examples, the N uplink grants may be identified based at least in
part on a network load (e.g., a load on the network access device
205 or another network node), or an estimate of a number of
collisions between transmissions of a random access preamble by
different UEs, or an estimate of a number of collisions between
transmissions by different UEs using a same uplink grant included
in a random access response message, or a number of channel
elements in a receiver of the network access device 205, or a
number of available transmission resources, or a time of receipt of
a random access preamble, or combinations thereof. UEs may select
one of the N uplink grants for making a first scheduled UL
transmission at 220. The N different transmission resources
associated with the N different uplink grants may differ, for
example, based at least in part on different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof. If each UE selects one
of the N uplink grants randomly, the probability of a collision
occurring at 220 may be reduced by a factor of N. When the
additional transmission resources allocated for the N uplink grants
include unoccupied or available transmission resources, a scenario
in which some of the uplink grants are not selected or used by a UE
provides no loss in system capacity, because the transmission
resources would not have been used anyway.
[0086] FIG. 3 shows examples of random access preamble selections
and uplink grant selections 300 made by a plurality of UEs when
performing respective random access procedures at the same time, in
accordance with one or more aspects of the present disclosure. By
way of example, the selections are made by a first UE (e.g., a UE
A), a second UE (e.g., a UE B), and a third UE (e.g., UE C). UE A,
UE B, and UE C may be examples of aspects of the UEs 115 described
with reference to FIG. 1 or 2.
[0087] As shown in FIG. 3, each of UE A, UE B, and UE C may select
a random access preamble from a set of preamble sequences 305. By
way of example, the set of preamble sequences 305 is shown to
include m preamble sequences, including, for example, a Sequence 1,
a Sequence 2, and a Sequence m. UE A and UE B are shown to randomly
select Sequence 1, and UE C is shown to randomly select Sequence 2.
Each of UE A, UE B, and UE C may transmit its selected random
access preamble to a network access device. The transmission of
Sequence 1 by both UE A and UE B may cause the network access
device to receive greater energy Sequence 1 at a higher energy than
Sequence 2.
[0088] Upon receipt of Sequence 1 and Sequence 2, the network
access device may identify a first number of uplink grants 310-a to
associate with Sequence 1, and a second number of uplink grants
310-b to associate with Sequence 2. By way of example, the network
access device is shown to identify n uplink grants for each of
Sequence 1 and Sequence 2, in which n includes a plurality of
uplink grants. The n uplink grants are shown to include Grant 1_1
(associated with TC-RNTI1_1), Grant 1_2 (associated with
TC-RNTI1_2), and Grant 1_n (associated with TC-RNTI1_n) associated
with Sequence 1, and Grant 2_1 (associated with TC-RNTI2_1), Grant
2_2 (associated with TC-RNTI2_2), and Grant 2_n (associated with
TC-RNTI2_n) associated with Sequence 2. In other examples, the
network access device may identify one uplink grant (e.g., n=1) for
each of Sequence 1 and Sequence 2, or the network access device may
identify different numbers of uplink grants for each of Sequence 1
and Sequence 2. The uplink grants associated with Sequence 1 may be
transmitted by the network access device in a random access
response message 315 including a Response 1 (directed to UEs that
transmitted a random access preamble corresponding to Sequence 1)
and a Response 2 (directed to UEs that transmitted a random access
preamble corresponding to Sequence 2). Alternatively, the uplink
grants corresponding to Sequence 1 and Sequence 2 may be
transmitted in different random access response messages.
[0089] Each uplink grant included in the random access response
message(s) transmitted by the network access device may be
associated with a different transmission resource, so that when
each of UE A, UE B, and UE C selects a different uplink grant for
transmitting a first scheduled UL transmission, the scheduled UL
transmissions are transmitted using different transmission
resources and do not collide. In some examples, the different
transmission resources associated with the different uplink grants
may include at least one of different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof. FIG. 3 shows an example
in which different uplink grants may be associated with different
time resources and/or frequency resources.
[0090] At 320, each of UE A, UE B, and UE C may select an uplink
grant associated with the preamble sequence on which its random
access preamble was based. In some examples, the uplink grants may
be randomly selected by the UEs. By way of example, FIG. 3 shows UE
A having selected Grant 1_1 (at 320-a), UE B having selected Grant
1_n (at 320-b), and UE C having selected Grant 2_2 (at 320-c).
Because UE A and UE B selected different uplink grants associated
with different transmission resources, their scheduled UL
transmissions (e.g., at 220 of FIG. 2) will not collide.
Additionally or alternatively, the scheduled UL transmission of UE
C will not collide with the scheduled UL transmissions of UE A and
UE B (e.g., at 220) because its schedule UL transmission is
transmitted using different transmission resources that differ from
the transmission resources used by UE A and UE B.
[0091] In some examples, the timing advance (TA) used for the
uplink grants associated with Sequence 1 may differ from the TA
used for the uplink grants associated with Sequence 2 (e.g., TA1
may be associated with Sequence 1, and TA2 may be associated with
Sequence 2), but the same TA (e.g., TA1) may be used for the uplink
grants associated with Sequence 1, and the same TA (e.g., TA2) may
be used for the uplink grants associated with Sequence 2.
Alternatively, the same TA may be used for both the uplink grants
associated with Sequence 1 and the uplink grants associated with
Sequence 2, or different TAs may be used for different uplink
grants associated with Sequence 1, or different TAs may be used for
different uplink grants associated with Sequence 2.
[0092] In some examples, two different uplink grants that are
associated with a same preamble sequence may be associated with the
same time and frequency resources, but different scrambling codes.
In these examples, a network access device may distinguish the
scheduled UL transmissions of two different UEs, which UEs
respectively use the two different uplink grants for their
scheduled UL transmissions (e.g., at 220 of FIG. 2), based on the
different scrambling codes associated with the scheduled UL
transmissions.
[0093] As another example, two different uplink grants may be
associated with all of the same transmission resources but for UE
IDs (e.g., the two different uplink grants may be associated with
different TC-RNTIs, as shown in the uplink grants 310-c of Response
1 of the random access response message 315-a shown in the
selections 400 of FIG. 4). In these examples, two different UEs may
randomly select two different uplink grants associated with a same
preamble sequence (e.g., UE A may select a first uplink grant
(Grant 1_1, TC-RNTI1_1) at 320-d, and UE B may select a second
uplink grant (Grant 1_1, TC-RNTI1_n) at 320-e), and each UE may
transmit a respective scheduled UL transmission using its selected
uplink grant. A network access device may distinguish the scheduled
UL transmissions of the UEs (e.g., the scheduled UL transmissions
of UE A and UE B) based at least in part on the different TC-RNTIs
associated with the scheduled UL transmissions. In some examples,
the network access device may use interference cancellation to
cancel the interference that one or more scheduled UL transmissions
impart on another scheduled UL transmission.
[0094] In some examples, a network access device (e.g., a base
station 105 described with reference to FIG. 1, or the network
access device 205 described with reference to FIG. 2) may not be
able to determine one or more aspects of a UE from the transmission
of a random access preamble and/or first scheduled UL transmission
received from the UE. For example, the network access device 205
may not be aware of a service used by the UE, a service requirement
of the UE, a transmission need of the UE, a capability of the UE,
etc. A network access device's inability to determine some aspects
of a UE may limit the network access device's ability to tailor a
response to the UE. For example, the network access device may not
communicate with the UE using a modulation and coding scheme (MCS)
or rank tailored to the UE, or the network access device may not
provide the UE with an uplink grant tailored to the UE.
[0095] In some examples, a service requirement of a UE may include
a QoS requirement of the UE (e.g., a QoS requirement of a service
used by the UE), an access priority of the UE (e.g., an access
priority of a service used by the UE), etc. In some examples, a
transmission need of the UE may be based at least in part on an
amount of data in a transmit buffer of the UE. In some examples, a
capability of the UE may include a maximum channel bandwidth
supported by the UE, which maximum channel bandwidth may be greater
than, equal to, or less than the maximum channel bandwidth that a
network access device or other network node may provide the UE. In
some examples, a capability of the UE may include a feature set
(e.g., one or more features) supported by the UE.
[0096] In some examples, a service requirement of a UE may include
different slices supported by the UE. In some examples, different
slices correspond to different services offered by the UE. In some
examples, different slices correspond to different services
supported by the network supported by the UE. In some examples,
different slices correspond to different network slices. In some
examples, a physical network may be partitioned into multiple
virtual networks (i.e., different slices) allowing a subscriber to
offer optimal support for different types of services.
[0097] To enable a network access device to identify one or more
aspects of a UE, the network access device (or other network node)
may associate at least two of the uplink grants associated with a
preamble sequence with different feature sets (with each feature
set including at least one feature), or with different maximum
channel bandwidths, or with different payload sizes, or with
different sets of (one or more) services, or with different service
requirements, or with different QoS profiles, or with different
access priorities, or with combinations thereof.
[0098] Upon receiving a random access message including uplink
grants associated with potential aspects of a UE, the UE may select
an uplink grant for transmission of a first scheduled UL
transmission based at least in part on a service used by the UE, or
a service requirement of the UE, or a QoS requirement of the UE, or
an access priority of the UE, or different slices, or an amount of
data in a transmit buffer of the UE, or a maximum channel bandwidth
supported by the UE, or a feature set supported by the UE, or
combinations thereof.
[0099] Upon receiving a scheduled UL transmission from a UE, on a
transmission resource associated with an uplink grant, a network
access device may identify at least one aspect of the UE based at
least in part on the transmission resource on which transmission is
received.
[0100] FIG. 5 shows a block diagram 500 of an apparatus 515 for use
in wireless communication, in accordance with one or more aspects
of the present disclosure. The apparatus 515 may be an example of
aspects of one or more of the UEs 115 described with reference to
FIG. 1 or 2. The apparatus 515 may also be or include a processor.
The apparatus 515 may include a receiver 510, a wireless
communication manager 520-a, or a transmitter 530. Each of these
components may be in communication with each other.
[0101] The components of the apparatus 515 may, individually or
collectively, be implemented using one or more application-specific
integrated circuits (ASICs) adapted to perform some or all of the
applicable functions in hardware. Alternatively, the functions may
be performed by one or more other processing units (or cores), on
one or more integrated circuits. In some other examples, other
types of integrated circuits may be used (e.g., Structured/Platform
ASICs, Field Programmable Gate Arrays (FPGAs), a System-on-Chip
(SoC), and/or other types of Semi-Custom ICs), which may be
programmed in any manner known in the art. The functions of each
component may also be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors.
[0102] In some examples, the receiver 510 may include at least one
radio frequency (RF) receiver, such as at least one RF receiver
operable to receive transmissions over one or more radio frequency
spectrum bands. In some examples, the one or more radio frequency
spectrum bands may be used for LTE/LTE-A communications, as
described, for example, with reference to FIG. 1, 2, 3, or 4. The
receiver 510 may be used to receive various types of data or
control signals (i.e., transmissions) over one or more
communication links of a wireless communication system, such as one
or more communication links of the wireless communication system
100 described with reference to FIG. 1.
[0103] In some examples, the transmitter 530 may include at least
one RF transmitter, such as at least one RF transmitter operable to
transmit over one or more radio frequency spectrum bands. In some
examples, the one or more radio frequency spectrum bands may be
used for LTE/LTE-A communications, as described, for example, with
reference to FIG. 1, 2, 3, or 4. The transmitter 530 may be used to
transmit various types of data or control signals (i.e.,
transmissions) over one or more communication links of a wireless
communication system, such as one or more communication links of
the wireless communication system 100 described with reference to
FIG. 1.
[0104] In some examples, the wireless communication manager 520-a
may be used to manage one or more aspects of wireless communication
for the apparatus 515. In some examples, part of the wireless
communication manager 520-a may be incorporated into or shared with
the receiver 510 or the transmitter 530. In some examples, the
wireless communication manager 520-a may be an example of aspects
of the wireless communication manager 520 described with reference
to FIG. 1. In some examples, the wireless communication manager
520-a may include a random access preamble transmission manager
535, a random access response manager 540, or a scheduled uplink
transmission manager 545. The scheduled uplink transmission manager
545 may optionally include an uplink grant selector 550.
[0105] The random access preamble transmission manager 535 may be
used to transmitting a random access preamble.
[0106] The random access response manager 540 may be used to
receive a random access response message that includes a plurality
of uplink grants associated with the random access preamble. Each
uplink grant in the plurality of uplink grants may be associated
with a different transmission resource. In some examples, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of: different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof.
[0107] The uplink grant selector 550 may be used to select an
uplink grant from the plurality of uplink grants. In some examples,
selecting the uplink grant may include randomly selecting the
uplink grant from the plurality of uplink grants.
[0108] The scheduled uplink transmission manager 545 may be used to
transmit using the selected uplink grant.
[0109] FIG. 6 shows a block diagram 600 of a wireless communication
manager 520-b for use in wireless communication, in accordance with
one or more aspects of the present disclosure. The wireless
communication manager 520-b may be an example of aspects of the
wireless communication manager 520 described with reference to FIG.
1 or 5.
[0110] The components of the wireless communication manager 520-b
may, individually or collectively, be implemented using one or more
ASICs adapted to perform some or all of the applicable functions in
hardware. Alternatively, the functions may be performed by one or
more other processing units (or cores), on one or more integrated
circuits. In some other examples, other types of integrated
circuits may be used (e.g., Structured/Platform ASICs, FPGAs, a
SoC, and/or other types of Semi-Custom ICs), which may be
programmed in any manner known in the art. The functions of each
component may also be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors.
[0111] In some examples, the wireless communication manager 520-b
may be used to manage one or more aspects of wireless communication
for a UE or apparatus, such as one of the UEs 115 or apparatuses
515 described with reference to FIG. 1, 2, or 5. In some examples,
part of the wireless communication manager 520-b may be
incorporated into or shared with a receiver or a transmitter (e.g.,
the receiver 510 or the transmitter 530 described with reference to
FIG. 5). In some examples, the wireless communication manager 520-b
may include a random access preamble transmission manager 535-a, a
random access response manager 540-a, a scheduled uplink
transmission manager 545-a, or a contention resolution manager 610.
The random access preamble transmission manager 535-a may include a
random access preamble selector 605. The scheduled uplink
transmission manager 545-a may optionally include an uplink grant
selector 550-a.
[0112] The random access preamble transmission manager 535-a may be
used to transmitting a random access preamble. The random access
preamble selector 605 may be used to select the random access
preamble from a plurality of preamble sequences (e.g., 64 preamble
sequences).
[0113] The random access response manager 540-a may be used to
receive a random access response message that includes a plurality
of uplink grants associated with the random access preamble. Each
uplink grant in the plurality of uplink grants may be associated
with a different transmission resource. In some examples, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of: different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof.
[0114] The uplink grant selector 550-a may be used to select an
uplink grant from the plurality of uplink grants. In some examples,
selecting the uplink grant may include randomly selecting the
uplink grant from the plurality of uplink grants.
[0115] In some examples, the random access response manager 540-a
may receive at least two uplink grants associated with different
feature sets, and the uplink grant selector 550-a may select an
uplink grant based at least in part on a feature set supported by
the UE that includes the wireless communication manager 520-b. In
some examples, the random access response manager 540-a may receive
at least two uplink grants associated with different maximum
channel bandwidths, and the uplink grant selector 550-a may select
an uplink grant based at least in part on a maximum channel
bandwidth supported by the UE that includes the wireless
communication manager 520-b. In some examples, the random access
response manager 540-a may receive at least two uplink grants
associated with different payload sizes, and the uplink grant
selector 550-a may select an uplink grant based at least in part on
an amount of data in a transmit buffer of the UE that includes the
wireless communication manager 520-b. In some examples, the random
access response manager 540-a may receive at least two uplink
grants associated with at least one of different sets of services,
or different service requirements, or different QoS profiles, or
different access priorities, or different slices, or combinations
thereof, and the uplink grant selector 550-a may select an uplink
grant based at least in part on a service used by the UE that
includes the wireless communication manager 520-b, or a service
requirement of the UE, or a QoS requirement of the UE, or an access
priority of the UE, or different slices, or combinations
thereof.
[0116] The scheduled uplink transmission manager 545-a may be used
to transmit using the selected uplink grant. The contention
resolution manager 610 may be used to receive a contention
resolution message.
[0117] FIG. 7 shows a block diagram 700 of an apparatus 705 for use
in wireless communication, in accordance with one or more aspects
of the present disclosure. The apparatus 705 may be an example of
aspects of one or more of the base stations 105 or network access
devices 205 described with reference to FIG. 1 or 2. The apparatus
705 may also be or include a processor. The apparatus 705 may
include a receiver 710, a wireless communication manager 720-a, or
a transmitter 730. Each of these components may be in communication
with each other.
[0118] The components of the apparatus 705 may, individually or
collectively, be implemented using one or more ASICs adapted to
perform some or all of the applicable functions in hardware.
Alternatively, the functions may be performed by one or more other
processing units (or cores), on one or more integrated circuits. In
some other examples, other types of integrated circuits may be used
(e.g., Structured/Platform ASICs, FPGAs, a SoC, and/or other types
of Semi-Custom ICs), which may be programmed in any manner known in
the art. The functions of each component may also be implemented,
in whole or in part, with instructions embodied in a memory,
formatted to be executed by one or more general or
application-specific processors.
[0119] In some examples, the receiver 710 may include at least one
RF receiver, such as at least one RF receiver operable to receive
transmissions over one or more radio frequency spectrum bands. In
some examples, the one or more radio frequency spectrum bands may
be used for LTE/LTE-A communications, as described, for example,
with reference to FIG. 1, 2, 3, or 4. The receiver 710 may be used
to receive various types of data or control signals (i.e.,
transmissions) over one or more communication links of a wireless
communication system, such as one or more communication links of
the wireless communication system 100 described with reference to
FIG. 1.
[0120] In some examples, the transmitter 730 may include at least
one RF transmitter, such as at least one RF transmitter operable to
transmit over one or more radio frequency spectrum bands. In some
examples, the one or more radio frequency spectrum bands may be
used for LTE/LTE-A communications, as described, for example, with
reference to FIG. 1, 2, 3, or 4. The transmitter 730 may be used to
transmit various types of data or control signals (i.e.,
transmissions) over one or more communication links of a wireless
communication system, such as one or more communication links of
the wireless communication system 100 described with reference to
FIG. 1.
[0121] In some examples, the wireless communication manager 720-a
may be used to manage one or more aspects of wireless communication
for the apparatus 705. In some examples, part of the wireless
communication manager 720-a may be incorporated into or shared with
the receiver 710 or the transmitter 730. In some examples, the
wireless communication manager 720-a may be an example of aspects
of the wireless communication manager 720 described with reference
to FIG. 1. In some examples, the wireless communication manager
720-a may include a random access preamble reception manager 735 or
a random access response transmission manager 740. The random
access response transmission manager 740 may optionally include an
uplink grant manager 745.
[0122] The random access preamble reception manager 735 may be used
to receive a random access preamble.
[0123] The random access response transmission manager 740 may be
used to transmit a random access response message that includes a
plurality of uplink grants associated with the random access
preamble. Each uplink grant in the plurality of uplink grants may
be associated with a different transmission resource. In some
examples, a first transmission resource associated with a first
uplink grant and a second transmission resource associated with a
second uplink grant may include at least one of different
transmission times, or different transmission frequencies, or
different scrambling codes, or different channelization codes, or
different beam indices, or different UE IDs, or combinations
thereof.
[0124] The uplink grant manager 745 may be used to identify a
number of uplink grants associated with the random access preamble
received using the random access preamble reception manager 735,
for inclusion in the random access response message transmitted
using the random access response transmission manager 740. The
number of uplink grants may be identified based at least in part on
a network load, or an estimate of a number of collisions between
transmissions of the random access preamble by different UEs, or an
estimate of a number of collisions between transmissions by
different UEs using a same uplink grant included in a random access
response message, or a number of channel elements in a receiver of
the network access device, or a number of available transmission
resources, or a time of receipt of the random access preamble, or
combinations thereof.
[0125] FIG. 8 shows a block diagram 800 of a wireless communication
manager 720-b for use in wireless communication, in accordance with
one or more aspects of the present disclosure. The wireless
communication manager 720-b may be an example of aspects of the
wireless communication manager 720 described with reference to FIG.
1 or 7.
[0126] The components of the wireless communication manager 720-b
may, individually or collectively, be implemented using one or more
ASICs adapted to perform some or all of the applicable functions in
hardware. Alternatively, the functions may be performed by one or
more other processing units (or cores), on one or more integrated
circuits. In some other examples, other types of integrated
circuits may be used (e.g., Structured/Platform ASICs, FPGAs, a
SoC, and/or other types of Semi-Custom ICs), which may be
programmed in any manner known in the art. The functions of each
component may also be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors.
[0127] In some examples, the wireless communication manager 720-b
may be used to manage one or more aspects of wireless communication
for a network access device or apparatus, such as one of the base
stations 105, network access devices 205, or apparatuses 705
described with reference to FIG. 1, 2, or 7. In some examples, part
of the wireless communication manager 720-b may be incorporated
into or shared with a receiver or a transmitter (e.g., the receiver
710 or the transmitter 730 described with reference to FIG. 7). In
some examples, the wireless communication manager 720-b may include
a random access preamble reception manager 735-a, a random access
response transmission manager 740-a, a scheduled transmission
reception manager 805, a UE aspect identifier 810, or a contention
resolution manager 815. The random access response transmission
manager 740-a may optionally include an uplink grant manager
745-a.
[0128] The random access preamble reception manager 735-a may be
used to receive a random access preamble.
[0129] The random access response transmission manager 740-a may be
used to transmit a random access response message that includes a
number of uplink grants associated with a random access preamble.
Each uplink grant in the plurality of uplink grants may be
associated with a different transmission resource. In some
examples, a first transmission resource associated with a first
uplink grant and a second transmission resource associated with a
second uplink grant may include at least one of different
transmission times, or different transmission frequencies, or
different scrambling codes, or different channelization codes, or
different beam indices, or different UE IDs, or combinations
thereof.
[0130] The uplink grant manager 745-a may be used to identify a
number of uplink grants associated with a random access preamble
received using the random access preamble reception manager 735-a,
for inclusion in a random access response message transmitted using
the random access response transmission manager 740-a.
Alternatively or additionally, the uplink grant manager 745-a may
identify a number of uplink grants to associate with the random
access preamble based at least in part on a time-variable
parameter. In these latter examples, the identified number of
uplink grants may include at least one uplink grant (e.g., a single
uplink grant or a plurality of uplink grants) associated with at
least one transmission resource. The number of uplink grants may be
identified based at least in part on a network load, or an estimate
of a number of collisions between transmissions of the random
access preamble by different UEs, or an estimate of a number of
collisions between transmissions by different UEs using a same
uplink grant included in a random access response message, or a
number of channel elements in a receiver of the network access
device, or a number of available transmission resources, or a time
of receipt of the random access preamble, or combinations thereof.
In some examples, the uplink grant manager 745-a may associate at
least two uplink grants with different feature sets, or different
maximum channel bandwidths, or different payload sizes, or
different sets of services, or different service requirements, or
different QoS profiles, or different access priorities, or
different slices, or combinations thereof.
[0131] The scheduled transmission reception manager 805 may be used
to receive a transmission, from a UE, on a transmission resource
associated with an uplink grant in the plurality of uplink grants.
In some examples, the scheduled transmission reception manager 805
may receive transmissions from at least two UEs, on transmission
resources associated with at least two uplink grants in the
plurality of uplink grants.
[0132] The UE aspect identifier 810 may be used to identify, based
at least in part on the transmission resource on which the
transmission is received, at least one aspect of a UE. In some
examples, the at least one aspect of the UE may include a feature
set supported by the UE, or a channel bandwidth supported by the
UE, or an amount of data in a transmit buffer of the UE, or a
service used by the UE, or a service requirement of the UE, or a
QoS requirement of the UE, or an access priority of the UE, or
different slices, or combinations thereof.
[0133] The contention resolution manager 815 may be used to
transmit a contention resolution to the UE.
[0134] FIG. 9 shows a block diagram 900 of a UE 115-b for use in
wireless communication, in accordance with one or more aspects of
the present disclosure. The UE 115-b may be included or be part of
a personal computer (e.g., a laptop computer, a netbook computer, a
tablet computer, etc.), a cellular telephone, a PDA, a DVR, an
internet appliance, a gaming console, an e-reader, a vehicle, a
home appliance, a lighting or alarm control system, etc. The UE
115-b may, in some examples, have an internal power supply (not
shown), such as a small battery, to facilitate mobile operation. In
some examples, the UE 115-b may be an example of aspects of one or
more of the UEs 115 described with reference to FIG. 1, or aspects
of the apparatus 515 described with reference to FIG. 5. The UE
115-b may be configured to implement at least some of the UE or
apparatus techniques and functions described with reference to FIG.
1, 2, 3, 4, 5, or 6.
[0135] The UE 115-b may include a processor 910, a memory 920, at
least one transceiver (represented by transceiver(s) 930), at least
one antenna (represented by antenna(s) 940), or a wireless
communication manager 520-c. Each of these components may be in
communication with each other, directly or indirectly, over one or
more buses 935.
[0136] The memory 920 may include random access memory (RAM) or
read-only memory (ROM). The memory 920 may store computer-readable,
computer-executable code 925 containing instructions that are
configured to, when executed, cause the processor 910 to perform
various functions described herein related to wireless
communication, including, for example, performing a random access
procedure. Alternatively, the computer-executable code 925 may not
be directly executable by the processor 910 but be configured to
cause the UE 115-b (e.g., when compiled and executed) to perform
various of the functions described herein.
[0137] The processor 910 may include an intelligent hardware
device, e.g., a central processing unit (CPU), a microcontroller,
an ASIC, etc. The processor 910 may process information received
through the transceiver(s) 930 or information to be sent to the
transceiver(s) 930 for transmission through the antenna(s) 940. The
processor 910 may handle, alone or in connection with the wireless
communication manager 520-c, various aspects of communicating over
(or managing communications over) one or more radio frequency
spectrum bands.
[0138] The transceiver(s) 930 may include a modem configured to
modulate packets and provide the modulated packets to the
antenna(s) 940 for transmission, and to demodulate packets received
from the antenna(s) 940. The transceiver(s) 930 may, in some
examples, be implemented as one or more transmitters and one or
more separate receivers. The transceiver(s) 930 may support
communications in one or more radio frequency spectrum bands. The
transceiver(s) 930 may be configured to communicate
bi-directionally, via the antenna(s) 940, with one or more of the
base stations 105 or network access devices 205 described with
reference to FIG. 1 or 2, or the apparatus 705 described with
reference to FIG. 7. While the UE 115-b may include a single
antenna, there may be examples in which the UE 115-b may include
multiple antennas 940.
[0139] The wireless communication manager 520-c may be configured
to perform or control some or all of the UE or apparatus techniques
or functions described with reference to FIG. 1, 2, 3, 4, 5, or 6
related to wireless communication over one or more radio frequency
spectrum bands. The wireless communication manager 520-c, or
portions of it, may include a processor, or some or all of the
functions of the wireless communication manager 520-c may be
performed by the processor 910 or in connection with the processor
910. In some examples, the wireless communication manager 520-c may
be an example of the wireless communication manager 520 described
with reference to FIG. 1, 5, or 6.
[0140] FIG. 10 shows a block diagram 1000 of a network access
device 205-a for use in wireless communication, in accordance with
one or more aspects of the present disclosure. In some examples,
the network access device 205-a may be an example of one or more
aspects of a network access device 205 (e.g., a radio head, a base
station 105, an eNB, or an ANC) described with reference to FIG. 1
or 2, or aspects of the apparatus 705 described with reference to
FIG. 7. The network access device 205-a may be configured to
implement or facilitate at least some of the network access device
techniques and functions described with reference to FIG. 1, 2, 3,
4, 7, or 8.
[0141] The network access device 205-a may include a processor
1010, a memory 1020, at least one transceiver (represented by
transceiver(s) 1050), at least one antenna (represented by base
station antenna(s) 1055), or a wireless communication manager
720-c. The network access device 205-a may also include one or more
of a network access device communicator 1030 or a network
communicator 1040. Each of these components may be in communication
with each other, directly or indirectly, over one or more buses
1035.
[0142] The memory 1020 may include RAM or ROM. The memory 1020 may
store computer-readable, computer-executable code 1025 containing
instructions that are configured to, when executed, cause the
processor 1010 to perform various functions described herein
related to wireless communication, including, for example,
participating in a random access procedure performed by a UE.
Alternatively, the computer-executable code 1025 may not be
directly executable by the processor 1010 but be configured to
cause the network access device 205-a (e.g., when compiled and
executed) to perform various of the functions described herein.
[0143] The processor 1010 may include an intelligent hardware
device, e.g., a CPU, a microcontroller, an ASIC, etc. The processor
1010 may process information received through the transceiver(s)
1050, the network access device communicator 1030, or the network
communicator 1040. The processor 1010 may also process information
to be sent to the transceiver(s) 1050 for transmission through the
antenna(s) 1055, to the network access device communicator 1030,
for transmission to one or more other network access devices (e.g.,
network access device 205-b and network access device 205-c), or to
the network communicator 1040 for transmission to a core network
130-a, which may be an example of one or more aspects of the core
network 130 described with reference to FIG. 1. The processor 1010
may handle, alone or in connection with the wireless communication
manager 720-c, various aspects of communicating over (or managing
communications over) one or more radio frequency spectrum
bands.
[0144] The transceiver(s) 1050 may include a modem configured to
modulate packets and provide the modulated packets to the
antenna(s) 1055 for transmission, and to demodulate packets
received from the antenna(s) 1055. The transceiver(s) 1050 may, in
some examples, be implemented as one or more transmitters and one
or more separate receivers. The transceiver(s) 1050 may support
communications in one or more radio frequency spectrum bands. The
transceiver(s) 1050 may be configured to communicate
bi-directionally, via the antenna(s) 1055, with one or more UEs or
apparatuses, such as one of the UEs 115 described with reference to
FIG. 1, 2, or 9, or the apparatus 515 described with reference to
FIG. 5. The network access device 205-a may, for example, include
multiple antennas 1055 (e.g., an antenna array). The network access
device 205-a may communicate with the core network 130-a through
the network communicator 1040. The network access device 205-a may
also communicate with other network access devices, such as the
network access device 205-b and the network access device 205-c,
using the network access device communicator 1030.
[0145] The wireless communication manager 720-c may be configured
to perform or control some or all of the network access device or
apparatus techniques or functions described with reference to FIG.
1, 2, 3, 4, 7, or 8 related to wireless communication over one or
more radio frequency spectrum bands. The wireless communication
manager 720-c, or portions of it, may include a processor, or some
or all of the functions of the wireless communication manager 720-c
may be performed by the processor 1010 or in connection with the
processor 1010. In some examples, the wireless communication
manager 720-c may be an example of the wireless communication
manager 720 described with reference to FIG. 1, 7, or 8.
[0146] FIG. 11 is a flow chart illustrating an example of a method
1100 for wireless communication at a UE, in accordance with one or
more aspects of the present disclosure. For clarity, the method
1100 is described below with reference to aspects of one or more of
the UE 115 described with reference to FIG. 1, 2, or 9, aspects of
the apparatus 515 described with reference to FIG. 5, or aspects of
one or more of the wireless communication managers 520 described
with reference to FIG. 1, 5, 6, or 9. In some examples, a UE may
execute one or more sets of codes to control the functional
elements of the UE to perform the functions described below.
Additionally or alternatively, the UE may perform one or more of
the functions described below using special-purpose hardware.
[0147] At block 1105, the method 1100 may include transmitting a
random access preamble. The operation(s) at block 1105 may be
performed using the wireless communication manager 520 described
with reference to FIG. 1, 5, 6, or 9, or the random access preamble
transmission manager 535 described with reference to FIG. 5 or
6.
[0148] At block 1110, the method 1100 may include receiving a
random access response message that includes a plurality of uplink
grants associated with the random access preamble. Each uplink
grant in the plurality of uplink grants may be associated with a
different transmission resource. In some examples, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of: different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof. The operation(s) at
block 1110 may be performed using the wireless communication
manager 520 described with reference to FIG. 1, 5, 6, or 9, or the
random access response manager 540 described with reference to FIG.
5 or 6.
[0149] At block 1115, the method 1100 may include selecting an
uplink grant from the plurality of uplink grants. In some examples,
selecting the uplink grant may include randomly selecting the
uplink grant from the plurality of uplink grants. The operation(s)
at block 1115 may be performed using the wireless communication
manager 520 described with reference to FIG. 1, 5, 6, or 9, or the
uplink grant selector 550 described with reference to FIG. 5 or
6.
[0150] At block 1120, the method 1100 may include transmitting
using the selected uplink grant. The operation(s) at block 1120 may
be performed using the wireless communication manager 520 described
with reference to FIG. 1, 5, 6, or 9, or the scheduled uplink
transmission manager 545 described with reference to FIG. 5 or
6.
[0151] At block 1125, the method 1100 may optionally include
receiving a contention resolution message. The operation(s) at
block 1125 may be performed using the wireless communication
manager 520 described with reference to FIG. 1, 5, 6, or 9, or the
contention resolution manager 610 described with reference to FIG.
6.
[0152] In some examples of the method 1100, at least two of the
uplink grants may be associated with different feature sets, and
the uplink grant selected at block 1115 may be selected based at
least in part on a feature set supported by the UE. In some
examples, at least two of the uplink grants may be associated with
different maximum channel bandwidths, and the uplink grant selected
at block 1115 may be selected based at least in part on a maximum
channel bandwidth supported by the UE. In some examples, at least
two of the uplink grants may be associated with different payload
sizes, and the uplink grant selected at block 1115 may be selected
based at least in part on an amount of data in a transmit buffer of
the UE. In some examples, at least two of the uplink grants may be
associated with at least one of different sets of services, or
different service requirements, or different QoS profiles, or
different access priorities, or different slices, or combinations
thereof, and the uplink grant selected at block 1115 may be
selected based at least in part on a service used by the UE, or a
service requirement of the UE, or a QoS requirement of the UE, or
an access priority of the UE, or different slices, or combinations
thereof.
[0153] FIG. 12 is a flow chart illustrating an example of a method
1200 for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure. For
clarity, the method 1200 is described below with reference to
aspects of one or more of the base stations 105 described with
reference to FIG. 1, aspects of one of the network access devices
205 described with reference to FIG. 2 or 10, aspects of the
apparatus 705 described with reference to FIG. 7, or aspects of one
or more of the wireless communication managers 720 described with
reference to FIG. 1, 7, 8, or 10. In some examples, a network
access device may execute one or more sets of codes to control the
functional elements of the network access device to perform the
functions described below. Additionally or alternatively, the
network access device may perform one or more of the functions
described below using special-purpose hardware.
[0154] At block 1205, the method 1200 may include receiving a
random access preamble. The operation(s) at block 1205 may be
performed using the wireless communication manager 720 described
with reference to FIG. 1, 7, 8, or 10, or the random access
preamble reception manager 735 described with reference to FIG. 7
or 8.
[0155] At block 1210, the method 1200 may include transmitting a
random access response message that includes a plurality of uplink
grants associated with the random access preamble. Each uplink
grant in the plurality of uplink grants may be associated with a
different transmission resource. In some examples, a first
transmission resource associated with a first uplink grant and a
second transmission resource associated with a second uplink grant
may include at least one of different transmission times, or
different transmission frequencies, or different scrambling codes,
or different channelization codes, or different beam indices, or
different UE IDs, or combinations thereof. The operation(s) at
block 1210 may be performed using the wireless communication
manager 720 described with reference to FIG. 1, 7, 8, or 10, or the
random access response transmission manager 740 described with
reference to FIG. 7 or 8.
[0156] FIG. 13 is a flow chart illustrating an example of a method
1300 for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure. For
clarity, the method 1300 is described below with reference to
aspects of one or more of the base stations 105 described with
reference to FIG. 1, aspects of one or more of the network access
devices 205 described with reference to FIG. 2 or 10, aspects of
the apparatus 705 described with reference to FIG. 7, or aspects of
one or more of the wireless communication managers 720 described
with reference to FIG. 1, 7, 8, or 10. In some examples, a network
access device may execute one or more sets of codes to control the
functional elements of the network access device to perform the
functions described below. Additionally or alternatively, the
network access device may perform one or more of the functions
described below using special-purpose hardware.
[0157] At block 1305, the method 1300 may include receiving a
random access preamble. The operation(s) at block 1305 may be
performed using the wireless communication manager 720 described
with reference to FIG. 1, 7, 8, or 10, or the random access
preamble reception manager 735 described with reference to FIG. 7
or 8.
[0158] At block 1310, the method 1300 may optionally include
identifying a number of uplink grants associated with the random
access preamble. Each uplink grant in the number of uplink grants
may be associated with a different transmission resource. In some
examples, a first transmission resource associated with a first
uplink grant and a second transmission resource associated with a
second uplink grant may include at least one of different
transmission times, or different transmission frequencies, or
different scrambling codes, or different channelization codes, or
different beam indices, or different UE IDs, or combinations
thereof. The number of uplink grants may be identified based at
least in part on a network load, or an estimate of a number of
collisions between transmissions of the random access preamble by
different UEs, or an estimate of a number of collisions between
transmissions by different UEs using a same uplink grant included
in a random access response message, or a number of channel
elements in a receiver of the network access device, or a number of
available transmission resources, or a time of receipt of the
random access preamble, or combinations thereof. The operation(s)
at block 1310 may be performed using the wireless communication
manager 720 described with reference to FIG. 1, 7, 8, or 10, or the
uplink grant manager 745 described with reference to FIG. 7 or
8.
[0159] At block 1315, the method 1300 may optionally include
associating at least two of a plurality of uplink grants (including
the number of uplink grants identified at block 1310) with
different feature sets, or different maximum channel bandwidths, or
different payload sizes, or different sets of services, or
different service requirements, or different QoS profiles, or
different access priorities, or different slices, or combinations
thereof. The operation(s) at block 1315 may be performed using the
wireless communication manager 720 described with reference to FIG.
1, 7, 8, or 10, or the uplink grant manager 745 described with
reference to FIG. 7 or 8.
[0160] At block 1320, the method 1300 may include transmitting a
random access response message that includes the plurality of
uplink grants. The operation(s) at block 1320 may be performed
using the wireless communication manager 720 described with
reference to FIG. 1, 7, 8, or 10, or the random access response
transmission manager 740 described with reference to FIG. 7 or
8.
[0161] At block 1325, the method 1300 may optionally include
receiving a transmission, from a UE, on a transmission resource
associated with an uplink grant in the plurality of uplink grants.
In some examples, the operation(s) at block 1325 may include
receiving transmissions from at least two UEs, on transmission
resources associated with at least two uplink grants in the
plurality of uplink grants. The operation(s) at block 1325 may be
performed using the wireless communication manager 720 described
with reference to FIG. 1, 7, 8, or 10, or the scheduled
transmission reception manager 805 described with reference to FIG.
8.
[0162] At block 1330, the method 1300 may optionally include
identifying, based at least in part on the transmission resource on
which the transmission is received, at least one aspect of the UE.
In some examples, the at least one aspect of the UE may include a
feature set supported by the UE, or a channel bandwidth supported
by the UE, or an amount of data in a transmit buffer of the UE, or
a service used by the UE, or a service requirement of the UE, or a
QoS requirement of the UE, or an access priority of the UE, or
different slices, or combinations thereof. The operation(s) at
block 1330 may be performed using the wireless communication
manager 720 described with reference to FIG. 1, 7, 8, or 10, or the
UE aspect identifier 810 described with reference to FIG. 8.
[0163] At block 1335, the method 1300 may optionally include
transmitting a contention resolution to the UE. The operation(s) at
block 1335 may be performed using the wireless communication
manager 720 described with reference to FIG. 1, 7, 8, or 10, or the
contention resolution manager 815 described with reference to FIG.
8.
[0164] FIG. 14 is a flow chart illustrating an example of a method
1400 for wireless communication at a network access device, in
accordance with one or more aspects of the present disclosure. For
clarity, the method 1400 is described below with reference to
aspects of one or more of the base stations 105 described with
reference to FIG. 1, aspects of one or more of the network access
devices 205 described with reference to FIG. 2 or 10, aspects of
the apparatus 705 described with reference to FIG. 7, or aspects of
one or more of the wireless communication managers 720 described
with reference to FIG. 1, 7, 8, or 10. In some examples, a network
access device may execute one or more sets of codes to control the
functional elements of the network access device to perform the
functions described below. Additionally or alternatively, the
network access device may perform one or more of the functions
described below using special-purpose hardware.
[0165] At block 1405, the method 1400 may include receiving a
random access preamble. The operation(s) at block 1405 may be
performed using the wireless communication manager 720 described
with reference to FIG. 1, 7, 8, or 10, or the random access
preamble reception manager 735 described with reference to FIG. 7
or 8.
[0166] At block 1410, the method 1400 may include identifying a
number of uplink grants to associate with the random access
preamble. The identified number of uplink grants may include at
least one uplink grant (e.g., a single uplink grant or a plurality
of uplink grants) associated with at least one transmission
resource. The identified number of uplink grants may be based at
least in part on a time-variable parameter. The operation(s) at
block 1410 may be performed using the wireless communication
manager 720 described with reference to FIG. 1, 7, 8, or 10, or the
uplink grant manager 745 described with reference to FIG. 7 or
8.
[0167] In some examples, the number of uplink grants may be
identified, at block 1410, based at least in part on a network
load, or an estimate of a number of collisions between
transmissions of the random access preamble by different UEs, or an
estimate of a number of collisions between transmissions by
different UEs using a same uplink grant included in the random
access response message, or a number of channel elements in a
receiver of the network access device, or a number of available
transmission resources, or a time of receipt of the random access
preamble, or combinations thereof.
[0168] At block 1415, the method 1400 may include transmitting a
random access response message including the identified number of
uplink grants. The operation(s) at block 1415 may be performed
using the wireless communication manager 720 described with
reference to FIG. 1, 7, 8, or 10, or the random access response
transmission manager 740 described with reference to FIG. 7 or
8.
[0169] The methods 1100, 1200, 1300, and 1400 described with
reference to FIGS. 11, 12, 13, and 14 may provide for wireless
communication. It should be noted that the methods 1100, 1200,
1300, and 1400 are just example implementations, and the operations
of the methods 1100, 1200, 1300, and 1400 may be rearranged or
otherwise modified such that other implementations are
possible.
[0170] Techniques described herein may be used for various wireless
communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and
other systems. The terms "system" and "network" are often used
interchangeably. 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 0 and A may be referred to as CDMA2000 1.times., 1.times.,
etc. IS-856 (TIA-856) may be referred to as CDMA2000 1.times.EV-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). 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.TM., etc. UTRA and E-UTRA
are part of Universal Mobile Telecommunication System (UMTS). 3GPP
LTE and LTE-A are new releases of UMTS that use E-UTRA. UTRA,
E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from
an organization named 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 above as well as other
systems and radio technologies, including cellular (e.g., LTE)
communications over an unlicensed or shared bandwidth. The
description above, however, describes an LTE/LTE-A system for
purposes of example, and LTE terminology is used in much of the
description above, although the techniques are applicable beyond
LTE/LTE-A applications.
[0171] The detailed description set forth above in connection with
the appended drawings describes examples and does not represent all
of the examples that may be implemented or that are within the
scope of the claims. The terms "example" and "exemplary," when used
in this description, mean "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 apparatuses are shown in block diagram form in order to avoid
obscuring the concepts of the described examples.
[0172] Information and signals 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 above description
may be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles, or any
combination thereof.
[0173] The various illustrative blocks and components described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a digital signal
processor (DSP), an ASIC, an FPGA or other programmable logic
device, 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.
[0174] 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 and spirit
of the disclosure and appended claims. For example, due to the
nature of software, functions described above can be implemented
using software executed by a processor, hardware, firmware,
hardwiring, or combinations of any of these. Features implementing
functions may be physically located at various positions, including
being distributed such that portions of functions are implemented
at different physical locations. As used herein, including in the
claims, the term "and/or," when used in a list of two or more
items, means that any one of the listed items can be employed by
itself, or any combination of two or more of the listed items can
be employed. For example, if a composition is described as
containing components A, B, and/or C, the composition can contain A
alone; B alone; C alone; A and B in combination; A and C in
combination; B and C in combination; or A, B, and C in combination.
Also, as used herein, including in the claims, "or" as used in a
list of items (for example, 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 phrase referring to "at
least one of" a list of items refers to any combination of those
items, including single members. As an example, "at least one of:
A, B, or C" is intended to cover A, B, C, A-B, A-C, B-C, and
A-B-C., as well as any combination with multiples of the same
element (e.g., A-A A-A-A, A-A-B, A-A-C, A-B-B, A-C-C, B-B, B-B-B,
B-B-C, C-C, and C-C-C or any other ordering of A, B, and C).
[0175] As used herein, the phrase "based on" shall not be construed
as a reference to a closed set of conditions. For example, an
exemplary feature 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."
[0176] 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 can comprise RAM, ROM, electrically
erasable programmable read-only memory (EEPROM), 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.
[0177] The previous description of the disclosure 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 to be limited to the
examples and designs described herein but is to be accorded the
broadest scope consistent with the principles and novel techniques
disclosed herein.
* * * * *