U.S. patent application number 15/703431 was filed with the patent office on 2019-03-14 for techniques and apparatuses for tune-away management.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Qingxin Chen, Chih-Ping Hsu, Kuo-Chun LEE, Omar Sabbarini, Min Wang.
Application Number | 20190082478 15/703431 |
Document ID | / |
Family ID | 65631934 |
Filed Date | 2019-03-14 |
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United States Patent
Application |
20190082478 |
Kind Code |
A1 |
LEE; Kuo-Chun ; et
al. |
March 14, 2019 |
TECHNIQUES AND APPARATUSES FOR TUNE-AWAY MANAGEMENT
Abstract
Certain aspects of the present disclosure generally relate to
wireless communication. In some aspects, a user equipment may
determine a predicted tune-away for a set of voice frames. In some
aspects, the user equipment may alter a vocoder rate from a first
vocoder rate to a second vocoder rate that is less than the first
vocoder rate based at least in part on determining the predicted
tune-away for the set of voice frames. In some aspects, the user
equipment may drop, in connection with an occurrence of the
predicted tune-away, a subset of packets for a time period
corresponding to the predicted tune-away. Numerous other aspects
are provided.
Inventors: |
LEE; Kuo-Chun; (San Diego,
CA) ; Chen; Qingxin; (San Diego, CA) ; Wang;
Min; (San Diego, CA) ; Hsu; Chih-Ping; (San
Diego, CA) ; Sabbarini; Omar; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
65631934 |
Appl. No.: |
15/703431 |
Filed: |
September 13, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 74/0816 20130101;
H04W 72/0446 20130101; H04L 47/38 20130101; H04L 47/32 20130101;
H04W 76/28 20180201; H04W 36/38 20130101; H04W 36/24 20130101 |
International
Class: |
H04W 76/04 20060101
H04W076/04; H04W 36/38 20060101 H04W036/38; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method of wireless communication, comprising: determining, by
a user equipment, a predicted tune-away for a set of voice frames;
altering, by the user equipment, a vocoder rate from a first
vocoder rate to a second vocoder rate that is less than the first
vocoder rate based at least in part on determining the predicted
tune-away for the set of voice frames; and receiving or
transmitting, by the user equipment, redundant data for packets
occurring during a time period corresponding to the predicted
tune-away.
2. The method of claim 1, wherein the second vocoder rate is
determined based at least in part on an uplink bandwidth
allocation.
3. The method of claim 1, wherein the second vocoder rate is
determined based at least in part on a bandwidth grant.
4. The method of claim 1, wherein the second vocoder rate is
determined based at least in part on an overhead
characteristic.
5. The method of claim 1, wherein the second vocoder rate is
determined based at least in part on the first vocoder rate.
6. The method of claim 1, wherein the predicted tune-away is
determined based at least in part on a paging cycle and a tune-away
start time.
7. The method of claim 1, wherein a tune-away duration for the
predicted tune-away is determined based at least in part on stored
information identifying at least one previous tune-away
duration.
8. The method of claim 1, wherein the predicted tune-away is
determined based at least in part on a cell change.
9. A user equipment, comprising: a memory; and one or more
processors operatively coupled to the memory, the one or more
processors configured to: determine a predicted tune-away for a set
of voice frames; and alter a vocoder rate from a first vocoder rate
to a second vocoder rate that is less than the first vocoder rate
based at least in part on determining the predicted tune-away for
the set of voice frames wherein activation of a channel aware mode
is signaled using in-band signaling or a real-time transport
protocol control protocol message.
10. The user equipment of claim 9, wherein the second vocoder rate
is determined based at least in part on an uplink bandwidth
allocation.
11. The user equipment of claim 9, wherein the second vocoder rate
is determined based at least in part on a bandwidth grant.
12. The user equipment of claim 9, wherein the second vocoder rate
is determined based at least in part on an overhead
characteristic.
13. The user equipment of claim 9, wherein the second vocoder rate
is determined based at least in part on the first vocoder rate.
14. The user equipment of claim 9, wherein the predicted tune-away
is determined based at least in part on a paging cycle and a
tune-away start time.
15. The user equipment of claim 9, wherein a tune-away duration for
the predicted tune-away is determined based at least in part on
stored information identifying at least one previous tune-away
duration.
16. A method of wireless communication, comprising: determining, by
a user equipment, a predicted tune-away for a set of voice frames;
and dropping, by the user equipment and in connection with an
occurrence of the predicted tune-away, a subset of packets for a
time period corresponding to the predicted tune-away,. wherein at
least one packet, occurring during the time period corresponding to
the predicted tune-away, is transmitted after the time period
corresponding to the predicted tune-away.
17. (canceled)
18. The method of claim 16, wherein a quantity of packets to be
dropped as the subset of packets is determined based at least in
part on a transmission queue parameter.
19. The method of claim 16, further comprising: transmitting, using
an enhanced voice services (EVS) codec, redundant data for packets
occurring during the time period corresponding to the predicted
tune-away.
20. The method of claim 19, wherein the user equipment is operating
in a channel aware mode.
21. The method of claim 19, wherein a channel aware mode is
activated for the time period corresponding to the predicted
tune-away and deactivated after the time period corresponding to
the predicted tune-away.
22. The method of claim 16, further comprising: receiving redundant
data for packets occurring during the time period corresponding to
the predicted tune-away.
23. The method of claim 16, wherein activation of a channel aware
mode is signaled using in-band signaling or a real-time transport
protocol control protocol message.
24. A user equipment, comprising: a memory; and one or more
processors operatively coupled to the memory, the one or more
processors configured to: determine a predicted tune-away for a set
of voice frames; and drop, in connection with an occurrence of the
predicted tune-away, a subset of packets for a time period
corresponding to the predicted tune-away, wherein a quantity of
packets to be dropped as the subset of packets is determined based
at least in part on a transmission queue parameter.
25. The user equipment of claim 24, wherein at least one packet,
occurring during the time period corresponding to the predicted
tune-away, is transmitted after the time period corresponding to
the predicted tune-away.
26. (canceled)
27. The user equipment of claim 24, wherein the one or more
processors are configured to: transmit, using an enhanced voice
services (EVS) codec, redundant data for packets occurring during
the time period corresponding to the predicted tune-away.
28. The user equipment of claim 27, wherein the user equipment is
operating in a channel aware mode.
29. The user equipment of claim 27, wherein a channel aware mode is
activated for the time period corresponding to the predicted
tune-away and deactivated after the time period corresponding to
the predicted tune-away.
30. The user equipment of claim 24, wherein the one or more
processors are configured to: receive redundant data for packets
occurring during the time period corresponding to the predicted
tune-away.
31. The method of claim 1, further comprising: signaling a channel
aware mode based at least in part on determining the predicted
tune-away for the set of voice frames.
32. The user equipment of claim 9, wherein the one or more
processors are configured to: signal a channel aware mode based at
least in part on determining the predicted tune-away for the set of
voice frames.
Description
FIELD OF THE DISCLOSURE
[0001] Aspects of the present disclosure generally relate to
wireless communication, and more particularly to techniques and
apparatuses for tune-away management.
BACKGROUND
[0002] Wireless communication systems are widely deployed to
provide various telecommunication services, such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power, and/or
the like). Examples of such multiple-access technologies include
code division multiple access (CDMA) systems, time division
multiple access (TDMA) systems, frequency division multiple access
(FDMA) systems, orthogonal frequency division multiple access
(OFDMA) systems, single-carrier frequency divisional multiple
access (SC-FDMA) systems, and time division synchronous code
division multiple access (TD-SCDMA) systems.
[0003] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, a national, a regional, and even a global level. An
example of a telecommunication standard is Long Term Evolution
(LTE). LTE is a set of enhancements to the Universal Mobile
Telecommunications System (UMTS) mobile standard promulgated by
Third Generation Partnership Project (3GPP). LTE is designed to
better support mobile broadband Internet access by improving
spectral efficiency, lowering costs, improving services, using new
spectrum, and integrating with other open standards using OFDMA on
the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input
multiple-output (MIMO) antenna technology.
SUMMARY
[0004] In some aspects, a method for wireless communication may
include determining, by a user equipment, a predicted tune-away for
a set of voice frames. The method may include altering, by the user
equipment, a vocoder rate from a first vocoder rate to a second
vocoder rate that is less than the first vocoder rate based at
least in part on determining the predicted tune-away for the set of
voice frames.
[0005] In some aspects, a user equipment for wireless communication
may include memory and one or more processors operatively coupled
to the memory. The memory and the one or more processors may be
configured to determine a predicted tune-away for a set of voice
frames. The memory and the one or more processors may be configured
to alter a vocoder rate from a first vocoder rate to a second
vocoder rate that is less than the first vocoder rate based at
least in part on determining the predicted tune-away for the set of
voice frames.
[0006] In some aspects, a non-transitory computer-readable medium
may store one or more instructions for wireless communication. The
one or more instructions, when executed by one or more processors
of a user equipment, may cause the one or more processors to
determine a predicted tune-away for a set of voice frames. The one
or more instructions, when executed by the one or more processors,
may cause the one or more processors to alter a vocoder rate from a
first vocoder rate to a second vocoder rate that is less than the
first vocoder rate based at least in part on determining the
predicted tune-away for the set of voice frames.
[0007] In some aspects, an apparatus for wireless communication may
include means for determining a predicted tune-away for a set of
voice frames. The apparatus may include means for altering a
vocoder rate from a first vocoder rate to a second vocoder rate
that is less than the first vocoder rate based at least in part on
determining the predicted tune-away for the set of voice
frames.
[0008] In some aspects, a method for wireless communication may
include determining, by a user equipment, a predicted tune-away for
a set of voice frames. The method may include dropping, by the user
equipment and in connection with an occurrence of the predicted
tune-away, a subset of packets for a time period corresponding to
the predicted tune-away.
[0009] In some aspects, a user equipment for wireless communication
may include memory and one or more processors operatively coupled
to the memory. The memory and the one or more processors may be
configured to determine a predicted tune-away for a set of voice
frames. The memory and the one or more processors may be configured
to drop, in connection with an occurrence of the predicted
tune-away, a subset of packets for a time period corresponding to
the predicted tune-away.
[0010] In some aspects, a non-transitory computer-readable medium
may store one or more instructions for wireless communication. The
one or more instructions, when executed by one or more processors
of a user equipment, may cause the one or more processors to
determine a predicted tune-away for a set of voice frames. The one
or more instructions, when executed by the one or more processors,
may cause the one or more processors to drop, in connection with an
occurrence of the predicted tune-away, a subset of packets for a
time period corresponding to the predicted tune-away.
[0011] In some aspects, an apparatus for wireless communication may
include means for determining a predicted tune-away for a set of
voice frames. The apparatus may include means for dropping, in
connection with an occurrence of the predicted tune-away, a subset
of packets for a time period corresponding to the predicted
tune-away.
[0012] Aspects generally include a method, apparatus, system,
computer program product, non-transitory computer-readable medium,
user equipment, wireless communication device, base station, and
processing system as substantially described herein with reference
to and as illustrated by the accompanying drawings and
specification.
[0013] The foregoing has outlined rather broadly the features and
technical advantages of examples according to the disclosure in
order that the detailed description that follows may be better
understood. Additional features 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
[0014] So that the manner in which the above-recited features of
the present disclosure can be understood in detail, a more
particular description, briefly summarized above, may be had by
reference to aspects, some of which are illustrated in the appended
drawings. It is to be noted, however, that the appended drawings
illustrate only certain typical aspects of this disclosure and are
therefore not to be considered limiting of its scope, for the
description may admit to other equally effective aspects. The same
reference numbers in different drawings may identify the same or
similar elements.
[0015] FIG. 1 is a diagram illustrating an example deployment in
which multiple wireless networks have overlapping coverage, in
accordance with various aspects of the present disclosure.
[0016] FIG. 2 is a diagram illustrating an example access network
in an LTE network architecture, in accordance with various aspects
of the present disclosure.
[0017] FIG. 3 is a diagram illustrating an example of a downlink
frame structure in LTE, in accordance with various aspects of the
present disclosure.
[0018] FIG. 4 is a diagram illustrating an example of an uplink
frame structure in LTE, in accordance with various aspects of the
present disclosure.
[0019] FIG. 5 is a diagram illustrating an example of a radio
protocol architecture for a user plane and a control plane in LTE,
in accordance with various aspects of the present disclosure.
[0020] FIG. 6 is a diagram illustrating example components of an
evolved Node B and a user equipment in an access network, in
accordance with various aspects of the present disclosure.
[0021] FIGS. 7A-7C are diagrams illustrating an example of
tune-away management, in accordance with various aspects of the
present disclosure.
[0022] FIG. 8 is a diagram illustrating an example process
performed, for example, by a user equipment, in accordance with
various aspects of the present disclosure.
[0023] FIG. 9 is a diagram illustrating an example process
performed, for example, by a user equipment, in accordance with
various aspects of the present disclosure.
DETAILED DESCRIPTION
[0024] The detailed description set forth below, in connection with
the appended drawings, is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
providing a thorough understanding of the various concepts.
However, it will be apparent to those skilled in the art that these
concepts may be practiced without these specific details.
[0025] The techniques described herein may be used for one or more
of various wireless communication networks such as code division
multiple access (CDMA) networks, time division multiple access
(TDMA) networks, frequency division multiple access (FDMA)
networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA
(SC-FDMA) networks, or other types of networks. A CDMA network may
implement a radio access technology (RAT) such as universal
terrestrial radio access (UTRA), CDMA2000, and/or the like. UTRA
may include wideband CDMA (WCDMA) and/or other variants of CDMA.
CDMA2000 may include Interim Standard (IS)-2000, IS-95 and IS-856
standards. IS-2000 may also be referred to as 1x radio transmission
technology (1xRTT), CDMA2000 1x, and/or the like. A TDMA network
may implement a RAT such as global system for mobile communications
(GSM), enhanced data rates for GSM evolution (EDGE), or GSM/EDGE
radio access network (GERAN). An OFDMA network may implement a RAT
such as evolved UTRA (E-UTRA), ultra mobile broadband (UMB),
Institute of Electrical and Electronics Engineers (IEEE) 802.11
(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and/or the
like. UTRA and E-UTRA may be part of the universal mobile
telecommunication system (UMTS). 3GPP long-term evolution (LTE) and
LTE-Advanced (LTE-A) are example releases of UMTS that use E-UTRA,
which employs OFDMA on the downlink and SC-FDMA on the uplink.
UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents
from an organization named "3rd Generation Partnership Project"
(3GPP). CDMA2000 and UMB are described in documents from an
organization named "3rd Generation Partnership Project 2" (3GPP2).
The techniques described herein may be used for the wireless
networks and RATs mentioned above as well as other wireless
networks and RATs.
[0026] FIG. 1 is a diagram illustrating an example deployment 100
in which multiple wireless networks have overlapping coverage, in
accordance with various aspects of the present disclosure. However,
wireless networks may not have overlapping coverage in aspects. As
shown, example deployment 100 may include an evolved universal
terrestrial radio access network (E-UTRAN) 105, which may include
one or more evolved Node Bs (eNBs) 110, and which may communicate
with other devices or networks via a serving gateway (SGW) 115
and/or a mobility management entity (MME) 120. As further shown,
example deployment 100 may include a radio access network (RAN)
125, which may include one or more base stations 130, and which may
communicate with other devices or networks via a mobile switching
center (MSC) 135 and/or an inter-working function (IWF) 140. As
further shown, example deployment 100 may include one or more user
equipment (UEs) 145 capable of communicating via E-UTRAN 105 and/or
RAN 125.
[0027] E-UTRAN 105 may support, for example, LTE or another type of
RAT. E-UTRAN 105 may include eNBs 110 and other network entities
that can support wireless communication for UEs 145. Each eNB 110
may provide communication coverage for a particular geographic
area. The term "cell" may refer to a coverage area of eNB 110
and/or an eNB subsystem serving the coverage area on a specific
frequency channel.
[0028] SGW 115 may communicate with E-UTRAN 105 and may perform
various functions, such as packet routing and forwarding, mobility
anchoring, packet buffering, initiation of network-triggered
services, and/or the like. MME 120 may communicate with E-UTRAN 105
and SGW 115 and may perform various functions, such as mobility
management, bearer management, distribution of paging messages,
security control, authentication, gateway selection, and/or the
like, for UEs 145 located within a geographic region served by MME
120 of E-UTRAN 105. The network entities in LTE are described in
3GPP TS 36.300, entitled "Evolved Universal Terrestrial Radio
Access (E-UTRA) and Evolved Universal Terrestrial Radio Access
Network (E-UTRAN); Overall description," which is publicly
available.
[0029] RAN 125 may support, for example, GSM or another type of
RAT. RAN 125 may include base stations 130 and other network
entities that can support wireless communication for UEs 145. MSC
135 may communicate with RAN 125 and may perform various functions,
such as voice services, routing for circuit-switched calls, and
mobility management for UEs 145 located within a geographic region
served by MSC 135 of RAN 125. In some aspects, IWF 140 may
facilitate communication between MME 120 and MSC 135 (e.g., when
E-UTRAN 105 and RAN 125 use different RATs). Additionally, or
alternatively, MME 120 may communicate directly with an MME that
interfaces with RAN 125, for example, without IWF 140 (e.g., when
E-UTRAN 105 and RAN 125 use a same RAT). In some aspects, E-UTRAN
105 and RAN 125 may use the same frequency and/or the same RAT to
communicate with UE 145. In some aspects, E-UTRAN 105 and RAN 125
may use different frequencies and/or RATs to communicate with UEs
145. As used herein, the term base station is not tied to any
particular RAT, and may refer to an eNB (e.g., of an LTE network)
or another type of base station associated with a different type of
RAT.
[0030] In general, any number of wireless networks may be deployed
in a given geographic area. Each wireless network may support a
particular RAT and may operate on one or more frequencies. A RAT
may also be referred to as a radio technology, an air interface,
and/or the like. A frequency or frequency ranges may also be
referred to as a carrier, a frequency channel, and/or the like.
Each frequency or frequency range may support a single RAT in a
given geographic area in order to avoid interference between
wireless networks of different RATs.
[0031] UE 145 may be stationary or mobile and may also be referred
to as a mobile station, a terminal, an access terminal, a wireless
communication device, a subscriber unit, a station, and/or the
like. UE 145 may be a cellular phone, a personal digital assistant
(PDA), a wireless modem, a wireless communication device, a
handheld device, a laptop computer, a cordless phone, a wireless
local loop (WLL) station, and/or the like. UE 145 may be included
inside a housing 145' that houses components of UE 145, such as
processor components, memory components, and/or the like.
[0032] Upon power up, UE 145 may search for wireless networks from
which UE 145 can receive communication services. If UE 145 detects
more than one wireless network, then a wireless network with the
highest priority may be selected to serve UE 145 and may be
referred to as the serving network. UE 145 may perform registration
with the serving network, if necessary. UE 145 may then operate in
a connected mode to actively communicate with the serving network.
Alternatively, UE 145 may operate in an idle mode and camp on the
serving network if active communication is not required by UE
145.
[0033] UE 145 may operate in the idle mode as follows. UE 145 may
identify all frequencies/RATs on which it is able to find a
"suitable" cell in a normal scenario or an "acceptable" cell in an
emergency scenario, where "suitable" and "acceptable" are specified
in the LTE standards. UE 145 may then camp on the frequency/RAT
with the highest priority among all identified frequencies/RATs. UE
145 may remain camped on this frequency/RAT until either (i) the
frequency/RAT is no longer available at a predetermined threshold
or (ii) another frequency/RAT with a higher priority reaches this
threshold. In some aspects, UE 145 may receive a neighbor list when
operating in the idle mode, such as a neighbor list included in a
system information block type 5 (SIB 5) provided by an eNB of a RAT
on which UE 145 is camped. Additionally, or alternatively, UE 145
may generate a neighbor list. A neighbor list may include
information identifying one or more frequencies, at which one or
more RATs may be accessed, priority information associated with the
one or more RATs, and/or the like.
[0034] The number and arrangement of devices and networks shown in
FIG. 1 are provided as an example. In practice, there may be
additional devices and/or networks, fewer devices and/or networks,
different devices and/or networks, or differently arranged devices
and/or networks than those shown in FIG. 1. Furthermore, two or
more devices shown in FIG. 1 may be implemented within a single
device, or a single device shown in FIG. 1 may be implemented as
multiple, distributed devices. Additionally, or alternatively, a
set of devices (e.g., one or more devices) shown in FIG. 1 may
perform one or more functions described as being performed by
another set of devices shown in FIG. 1.
[0035] FIG. 2 is a diagram illustrating an example access network
200 in an LTE network architecture, in accordance with various
aspects of the present disclosure. As shown, access network 200 may
include one or more eNBs 210 (sometimes referred to as "base
stations" herein) that serve a corresponding set of cellular
regions (cells) 220, one or more low power eNBs 230 that serve a
corresponding set of cells 240, and a set of UEs 250.
[0036] Each eNB 210 may be assigned to a respective cell 220 and
may be configured to provide an access point to a RAN. For example,
eNB 110, 210 may provide an access point for UE 145, 250 to E-UTRAN
105 (e.g., eNB 210 may correspond to eNB 110, shown in FIG. 1) or
may provide an access point for UE 145, 250 to RAN 125 (e.g., eNB
210 may correspond to base station 130, shown in FIG. 1). In some
cases, the terms base station and eNB may be used interchangeably,
and a base station, as used herein, is not tied to any particular
RAT. UE 145, 250 may correspond to UE 145, shown in FIG. 1. FIG. 2
does not illustrate a centralized controller for example access
network 200, but access network 200 may use a centralized
controller in some aspects. The eNBs 210 may perform radio related
functions including radio bearer control, admission control,
mobility control, scheduling, security, and network connectivity
(e.g., to SGW 115).
[0037] As shown in FIG. 2, one or more low power eNBs 230 may serve
respective cells 240, which may overlap with one or more cells 220
served by eNBs 210. The eNBs 230 may correspond to eNB 110
associated with E-UTRAN 105 and/or base station 130 associated with
RAN 125, shown in FIG. 1. A low power eNB 230 may be referred to as
a remote radio head (RRH). The low power eNB 230 may include a
femto cell eNB (e.g., home eNB (HeNB)), a pico cell eNB, a micro
cell eNB, and/or the like.
[0038] A modulation and multiple access scheme employed by access
network 200 may vary depending on the particular telecommunications
standard being deployed. In LTE applications, OFDM is used on the
downlink (DL) and SC-FDMA is used on the uplink (UL) to support
both frequency division duplexing (FDD) and time division duplexing
(TDD). The various concepts presented herein are well suited for
LTE applications. However, these concepts may be readily extended
to other telecommunication standards employing other modulation and
multiple access techniques. By way of example, these concepts may
be extended to Evolution-Data Optimized (EV-DO) or Ultra Mobile
Broadband (UMB). EV-DO and UMB are air interface standards
promulgated by the 3rd Generation Partnership Project 2 (3GPP2) as
part of the CDMA2000 family of standards and employs CDMA to
provide broadband Internet access to mobile stations. As another
example, these concepts may also be extended to UTRA employing
WCDMA and other variants of CDMA (e.g., such as TD-SCDMA, GSM
employing TDMA, E-UTRA, and/or the like), UMB, IEEE 802.11 (Wi-Fi),
IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM employing OFDMA,
and/or the like. UTRA, E-UTRA, UMTS, LTE and GSM are described in
documents from the 3GPP organization. CDMA2000 and UMB are
described in documents from the 3GPP2 organization. The actual
wireless communication standard and the multiple access technology
employed will depend on the specific application and the overall
design constraints imposed on the system.
[0039] The eNBs 210 may have multiple antennas supporting MIMO
technology. The use of MIMO technology enables eNBs 210 to exploit
the spatial domain to support spatial multiplexing, beamforming,
and transmit diversity. Spatial multiplexing may be used to
transmit different streams of data simultaneously on the same
frequency. The data streams may be transmitted to a single UE 145,
250 to increase the data rate or to multiple UEs 250 to increase
the overall system capacity. This may be achieved by spatially
precoding each data stream (e.g., applying a scaling of an
amplitude and a phase) and then transmitting each spatially
precoded stream through multiple transmit antennas on the DL. The
spatially precoded data streams arrive at the UE(s) 250 with
different spatial signatures, which enables each of the UE(s) 250
to recover the one or more data streams destined for that UE 145,
250. On the UL, each UE 145, 250 transmits a spatially precoded
data stream, which enables eNBs 210 to identify the source of each
spatially precoded data stream.
[0040] Spatial multiplexing is generally used when channel
conditions are good. When channel conditions are less favorable,
beamforming may be used to focus the transmission energy in one or
more directions. This may be achieved by spatially precoding the
data for transmission through multiple antennas. To achieve good
coverage at the edges of the cell, a single stream beamforming
transmission may be used in combination with transmit
diversity.
[0041] In the detailed description that follows, various aspects of
an access network will be described with reference to a MIMO system
supporting OFDM on the DL. OFDM is a spread-spectrum technique that
modulates data over a number of subcarriers within an OFDM symbol.
The subcarriers are spaced apart at precise frequencies. The
spacing provides "orthogonality" that enables a receiver to recover
the data from the subcarriers. In the time domain, a guard interval
(e.g., cyclic prefix) may be added to each OFDM symbol to combat
inter-OFDM-symbol interference. The UL may use SC-FDMA in the form
of a DFT-spread OFDM signal to compensate for high peak-to-average
power ratio (PAPR).
[0042] The number and arrangement of devices and cells shown in
FIG. 2 are provided as an example. In practice, there may be
additional devices and/or cells, fewer devices and/or cells,
different devices and/or cells, or differently arranged devices
and/or cells than those shown in FIG. 2. Furthermore, two or more
devices shown in FIG. 2 may be implemented within a single device,
or a single device shown in FIG. 2 may be implemented as multiple,
distributed devices. Additionally, or alternatively, a set of
devices (e.g., one or more devices) shown in FIG. 2 may perform one
or more functions described as being performed by another set of
devices shown in FIG. 2.
[0043] FIG. 3 is a diagram illustrating an example 300 of a
downlink (DL) frame structure in LTE, in accordance with various
aspects of the present disclosure. A frame (e.g., of 10 ms) may be
divided into 10 equally sized sub-frames with indices of 0 through
9. Each sub-frame may include two consecutive time slots. A
resource grid may be used to represent two time slots, each time
slot including a resource block (RB). The resource grid is divided
into multiple resource elements. In LTE, a resource block includes
12 consecutive subcarriers in the frequency domain and, for a
normal cyclic prefix in each OFDM symbol, 7 consecutive OFDM
symbols in the time domain, or 84 resource elements. For an
extended cyclic prefix, a resource block includes 6 consecutive
OFDM symbols in the time domain and has 72 resource elements. Some
of the resource elements, as indicated as R 310 and R 320, include
DL reference signals (DL-RS). The DL-RS include Cell-specific RS
(CRS) (also sometimes called common RS) 310 and UE-specific RS
(UE-RS) 320. UE-RS 320 are transmitted only on the resource blocks
upon which the corresponding physical DL shared channel (PDSCH) is
mapped. The number of bits carried by each resource element depends
on the modulation scheme. Thus, the more resource blocks that a UE
receives and the higher the modulation scheme, the higher the data
rate for the UE.
[0044] In LTE, an eNB may send a primary synchronization signal
(PSS) and a secondary synchronization signal (SSS) for each cell in
the eNB. The primary and secondary synchronization signals may be
sent in symbol periods 6 and 5, respectively, in each of subframes
0 and 5 of each radio frame with the normal cyclic prefix (CP). The
synchronization signals may be used by UEs for cell detection and
acquisition. The eNB may send a Physical Broadcast Channel (PBCH)
in symbol periods 0 to 3 in slot 1 of subframe 0. The PBCH may
carry certain system information.
[0045] The eNB may send a Physical Control Format Indicator Channel
(PCFICH) in the first symbol period of each subframe. The PCFICH
may convey the number of symbol periods (M) used for control
channels, where M may be equal to 1, 2 or 3 and may change from
subframe to subframe. M may also be equal to 4 for a small system
bandwidth, e.g., with less than 10 resource blocks. The eNB may
send a Physical HARQ Indicator Channel (PHICH) and a Physical
Downlink Control Channel (PDCCH) in the first M symbol periods of
each subframe. The PHICH may carry information to support hybrid
automatic repeat request (HARQ). The PDCCH may carry information on
resource allocation for UEs and control information for downlink
channels. The eNB may send a Physical Downlink Shared Channel
(PDSCH) in the remaining symbol periods of each subframe. The PDSCH
may carry data for UEs scheduled for data transmission on the
downlink.
[0046] The eNB may send the PSS, SSS, and PBCH in the center 1.08
MHz of the system bandwidth used by the eNB. The eNB may send the
PCFICH and PHICH across the entire system bandwidth in each symbol
period in which these channels are sent. The eNB may send the PDCCH
to groups of UEs in certain portions of the system bandwidth. The
eNB may send the PDSCH to specific UEs in specific portions of the
system bandwidth. The eNB may send the PSS, SSS, PBCH, PCFICH, and
PHICH in a broadcast manner to all UEs, may send the PDCCH in a
unicast manner to specific UEs, and may also send the PDSCH in a
unicast manner to specific UEs.
[0047] A number of resource elements may be available in each
symbol period. Each resource element (RE) may cover one subcarrier
in one symbol period and may be used to send one modulation symbol,
which may be a real or complex value. Resource elements not used
for a reference signal in each symbol period may be arranged into
resource element groups (REGs). Each REG may include four resource
elements in one symbol period. The PCFICH may occupy four REGs,
which may be spaced approximately equally across frequency, in
symbol period 0. The PHICH may occupy three REGs, which may be
spread across frequency, in one or more configurable symbol
periods. For example, the three REGs for the PHICH may all belong
in symbol period 0 or may be spread in symbol periods 0, 1, and 2.
The PDCCH may occupy 9, 18, 36, or 72 REGs, which may be selected
from the available REGs, in the first M symbol periods, for
example. Only certain combinations of REGs may be allowed for the
PDCCH.
[0048] A UE may know the specific REGs used for the PHICH and the
PCFICH. The UE may search different combinations of REGs for the
PDCCH. The number of combinations to search is typically less than
the number of allowed combinations for the PDCCH. An eNB may send
the PDCCH to the UE in any of the combinations that the UE will
search.
[0049] As indicated above, FIG. 3 is provided as an example. Other
examples are possible and may differ from what was described above
in connection with FIG. 3.
[0050] FIG. 4 is a diagram illustrating an example 400 of an uplink
(UL) frame structure in LTE, in accordance with various aspects of
the present disclosure. The available resource blocks for the UL
may be partitioned into a data section and a control section. The
control section may be formed at the two edges of the system
bandwidth and may have a configurable size. The resource blocks in
the control section may be assigned to UEs for transmission of
control information. The data section may include all resource
blocks not included in the control section. The UL frame structure
results in the data section including contiguous subcarriers, which
may allow a single UE to be assigned all of the contiguous
subcarriers in the data section.
[0051] A UE may be assigned resource blocks 410a, 410b in the
control section to transmit control information to an eNB. The UE
may also be assigned resource blocks 420a, 420b in the data section
to transmit data to the eNB. The UE may transmit control
information in a physical UL control channel (PUCCH) on the
assigned resource blocks in the control section. The UE may
transmit only data or both data and control information in a
physical UL shared channel (PUSCH) on the assigned resource blocks
in the data section. A UL transmission may span both slots of a
subframe and may hop across frequencies.
[0052] A set of resource blocks may be used to perform initial
system access and achieve UL synchronization in a physical random
access channel (PRACH) 430. The PRACH 430 carries a random sequence
and cannot carry any UL data/signaling. Each random access preamble
occupies a bandwidth corresponding to six consecutive resource
blocks. The starting frequency is specified by the network. That
is, the transmission of the random access preamble is restricted to
certain time and frequency resources. There is no frequency hopping
for the PRACH. The PRACH attempt is carried in a single subframe
(e.g., of 1 ms) or in a sequence of few contiguous subframes and a
UE can make only a single PRACH attempt per frame (e.g., of 10
ms).
[0053] As indicated above, FIG. 4 is provided as an example. Other
examples are possible and may differ from what was described above
in connection with FIG. 4.
[0054] FIG. 5 is a diagram illustrating an example 500 of a radio
protocol architecture for a user plane and a control plane in LTE,
in accordance with various aspects of the present disclosure. The
radio protocol architecture for the UE and the eNB is shown with
three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is
the lowest layer and implements various physical layer signal
processing functions. The L1 layer will be referred to herein as
the physical layer 510. Layer 2 (L2 layer) 520 is above the
physical layer 510 and is responsible for the link between the UE
and eNB over the physical layer 510.
[0055] In the user plane, the L2 layer 520 includes, for example, a
media access control (MAC) sublayer 530, a radio link control (RLC)
sublayer 540, and a packet data convergence protocol (PDCP)
sublayer 550, which are terminated at the eNB on the network side.
Although not shown, the UE may have several upper layers above the
L2 layer 520 including a network layer (e.g., IP layer) that is
terminated at a packet data network (PDN) gateway on the network
side, and an application layer that is terminated at the other end
of the connection (e.g., a far end UE, a server, and/or the
like).
[0056] The PDCP sublayer 550 provides retransmission of lost data
in handover. The PDCP sublayer 550 also provides header compression
for upper layer data packets to reduce radio transmission overhead,
security by ciphering the data packets, and handover support for
UEs between eNBs. The RLC sublayer 540 provides segmentation and
reassembly of upper layer data packets, retransmission of lost data
packets, and reordering of data packets to compensate for
out-of-order reception due to hybrid automatic repeat request
(HARQ). The MAC sublayer 530 provides multiplexing between logical
and transport channels. The MAC sublayer 530 is also responsible
for allocating the various radio resources (e.g., resource blocks)
in one cell among the UEs. The MAC sublayer 530 is also responsible
for HARQ operations.
[0057] In the control plane, the radio protocol architecture for
the UE and eNB is substantially the same for the physical layer 510
and the L2 layer 520 with the exception that there is no header
compression function for the control plane. The control plane also
includes a radio resource control (RRC) sublayer 560 in Layer 3 (L3
layer). The RRC sublayer 560 is responsible for obtaining radio
resources (i.e., radio bearers) and for configuring the lower
layers using RRC signaling between the eNB and the UE.
[0058] As indicated above, FIG. 5 is provided as an example. Other
examples are possible and may differ from what was described above
in connection with FIG. 5.
[0059] FIG. 6 is a diagram illustrating example components 600 of a
base station such as an eNB 110, 210, 230 and a UE 145, 250 in an
access network, in accordance with various aspects of the present
disclosure. As shown in FIG. 6, eNB 110, 210, 230 may include a
controller/processor 605, a TX processor 610, a channel estimator
615, an antenna 620, a transmitter 625TX, a receiver 625RX, an RX
processor 630, and a memory 635. As further shown in FIG. 6, UE
145, 250 may include a receiver RX, for example, of a transceiver
TX/RX 640, a transmitter TX, for example, of a transceiver TX/RX
640, an antenna 645, an RX processor 650, a channel estimator 655,
a controller/processor 660, a memory 665, a data sink 670, a data
source 675, and a TX processor 680.
[0060] In the DL, upper layer packets from the core network are
provided to controller/processor 605. The controller/processor 605
implements the functionality of the L2 layer. In the DL, the
controller/processor 605 provides header compression, ciphering,
packet segmentation and reordering, multiplexing between logical
and transport channels, and radio resource allocations to the UE
145, 250 based, at least in part, on various priority metrics. The
controller/processor 605 is also responsible for HARQ operations,
retransmission of lost packets, and signaling to the UE 145,
250.
[0061] The TX processor 610 implements various signal processing
functions for the L1 layer (e.g., physical layer). The signal
processing functions includes coding and interleaving to facilitate
forward error correction (FEC) at the UE 145, 250 and mapping to
signal constellations based, at least in part, on various
modulation schemes (e.g., binary phase-shift keying (BPSK),
quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK),
M-quadrature amplitude modulation (M-QAM)). The coded and modulated
symbols are then split into parallel streams. Each stream is then
mapped to an OFDM subcarrier, multiplexed with a reference signal
(e.g., pilot) in the time and/or frequency domain, and then
combined together using an Inverse Fast Fourier Transform (IFFT) to
produce a physical channel carrying a time domain OFDM symbol
stream. The OFDM stream is spatially precoded to produce multiple
spatial streams. Channel estimates from a channel estimator 615 may
be used to determine the coding and modulation scheme, as well as
for spatial processing. The channel estimate may be derived from a
reference signal and/or channel condition feedback transmitted by
the UE 145, 250. Each spatial stream is then provided to a
different antenna 620 via a separate transmitter TX, for example,
of transceiver TX/RX 625. Each such transmitter TX modulates an RF
carrier with a respective spatial stream for transmission.
[0062] At the UE 145, 250, each receiver RX, for example, of a
transceiver TX/RX 640 receives a signal through its respective
antenna 645. Each such receiver RX recovers information modulated
onto an RF carrier and provides the information to the receiver
(RX) processor 650. The RX processor 650 implements various signal
processing functions of the L1 layer. The RX processor 650 performs
spatial processing on the information to recover any spatial
streams destined for the UE 145, 250. If multiple spatial streams
are destined for the UE 145, 250, the spatial streams may be
combined by the RX processor 650 into a single OFDM symbol stream.
The RX processor 650 then converts the OFDM symbol stream from the
time-domain to the frequency domain using a Fast Fourier Transform
(FFT). The frequency domain signal comprises a separate OFDM symbol
stream for each subcarrier of the OFDM signal. The symbols on each
subcarrier, and the reference signal, are recovered and demodulated
by determining the most likely signal constellation points
transmitted by the eNB 110, 210, 230. These soft decisions may be
based, at least in part, on channel estimates computed by the
channel estimator 655. The soft decisions are then decoded and
deinterleaved to recover the data and control signals that were
originally transmitted by the eNB 110, 210, 230 on the physical
channel. The data and control signals are then provided to the
controller/processor 660.
[0063] The controller/processor 660 implements the L2 layer. The
controller/processor 660 can be associated with a memory 665 that
stores program codes and data. The memory 665 may include a
non-transitory computer-readable medium. In the UL, the
controller/processor 660 provides demultiplexing between transport
and logical channels, packet reassembly, deciphering, header
decompression, control signal processing to recover upper layer
packets from the core network. The upper layer packets are then
provided to a data sink 670, which represents all the protocol
layers above the L2 layer. Various control signals may also be
provided to the data sink 670 for L3 processing. The
controller/processor 660 is also responsible for error detection
using an acknowledgement (ACK) and/or negative acknowledgement
(NACK) protocol to support HARQ operations.
[0064] In the UL, a data source 675 is used to provide upper layer
packets to the controller/processor 660. The data source 675
represents all protocol layers above the L2 layer. Similar to the
functionality described in connection with the DL transmission by
the eNB 110, 210, 230, the controller/processor 660 implements the
L2 layer for the user plane and the control plane by providing
header compression, ciphering, packet segmentation and reordering,
and multiplexing between logical and transport channels based, at
least in part, on radio resource allocations by the eNB 110, 210,
230. The controller/processor 660 is also responsible for HARQ
operations, retransmission of lost packets, and signaling to the
eNB 110, 210, 230.
[0065] Channel estimates derived by a channel estimator 655 from a
reference signal or feedback transmitted by the eNB 110, 210, 230
may be used by the TX processor 680 to select the appropriate
coding and modulation schemes, and to facilitate spatial
processing. The spatial streams generated by the TX processor 680
are provided to different antenna 645 via separate transmitters TX,
for example, of transceivers TX/RX 640. Each transmitter TX, for
example, of transceiver TX/RX 640 modulates an RF carrier with a
respective spatial stream for transmission.
[0066] The UL transmission is processed at the eNB 110, 210, 230 in
a manner similar to that described in connection with the receiver
function at the UE 145, 250. Each receiver RX, for example, of
transceiver TX/RX 625 receives a signal through its respective
antenna 620. Each receiver RX, for example, of transceiver TX/RX
625 recovers information modulated onto an RF carrier and provides
the information to a RX processor 630. The RX processor 630 may
implement the L1 layer.
[0067] The controller/processor 605 implements the L2 layer. The
controller/processor 605 can be associated with a memory 635 that
stores program code and data. The memory 635 may be referred to as
a computer-readable medium. In the UL, the controller/processor 605
provides demultiplexing between transport and logical channels,
packet reassembly, deciphering, header decompression, control
signal processing to recover upper layer packets from the UE 145,
250. Upper layer packets from the controller/processor 605 may be
provided to the core network. The controller/processor 605 is also
responsible for error detection using an ACK and/or NACK protocol
to support HARQ operations.
[0068] In some aspects, one or more components of UE 145, 250 may
be included in a housing 145', as shown in FIG. 1. One or more
components of UE 145, 250 may be configured to perform tune-away
management, as described in more detail elsewhere herein. For
example, the controller/processor 660 and/or other processors and
modules of UE 145, 250 may perform or direct operations of, for
example, process 800 of FIG. 8, process 900 of FIG. 9, and/or other
processes as described herein. In some aspects, one or more of the
components shown in FIG. 6 may be employed to perform, for example,
process 800 of FIG. 8, process 900 of FIG. 9, and/or other
processes for the techniques described herein.
[0069] In some aspects, UE 145, 250 may include means for
determining a predicted tune-away for a set of voice frames, means
for altering a vocoder rate from a first vocoder rate to a second
vocoder rate that is less than the first vocoder rate based at
least in part on determining the predicted tune-away for the set of
voice frames, means for dropping, in connection with an occurrence
of the predicted tune-away, a subset of packets for a time period
corresponding to the predicted tune-away, and/or the like. In some
aspects, such means may include one or more components of UE 145,
250 described in connection with FIG. 6.
[0070] The number and arrangement of components shown in FIG. 6 are
provided as an example. In practice, there may be additional
components, fewer components, different components, or differently
arranged components than those shown in FIG. 6. Furthermore, two or
more components shown in FIG. 6 may be implemented within a single
component, or a single component shown in FIG. 6 may be implemented
as multiple, distributed components. Additionally, or
alternatively, a set of components (e.g., one or more components)
shown in FIG. 6 may perform one or more functions described as
being performed by another set of components shown in FIG. 6.
[0071] During a call, such as a voice over long term evolution
(VoLTE) call, voice frames may be transported using packets. For
example, 20 millisecond (ms) voice frames may be transported using
real-time transport protocol (RTP), user datagram protocol (UDP),
Internet protocol (IP), and/or the like. A BS may enable
semi-persistent scheduling (SPS) to allocate bandwidth for
transporting packets of a VoLTE call. For example, the BS may
configure an uplink bandwidth sequence, periodically provide an
uplink grant to a UE, and/or the like in an SPS mode. In this case,
each periodic uplink grant of bandwidth for the UE may enable the
UE to provide a packet. For example, the UE may encapsulate a
single 20 ms voice frame into a single IP packet for transport to a
network using a single uplink grant.
[0072] In some cases, a UE may be configured to tune-away from a
serving BS, for example, to monitor for a reference signal. For
example, when the UE is a single radio dual subscriber
identification module dual standby (DSDS) type of UE, the UE may
tune from the serving BS to scan for other coverage, monitor for a
reference signal from another BS, and/or the like. However, a
tune-away may interrupt transmission of a voice frame via a packet
in a VoLTE service. For example, a tune-away from an LTE signal to
a GSM signal, a 1x signal, and/or the like may cause a packet
delay. Additionally, or alternatively, when the BS fails to provide
a threshold amount of resources via a dynamic uplink grant or a
configured SPS periodic uplink grant, the UE may drop one or more
packets as a result of the tune-away. Additionally, or
alternatively, the UE may fail to receive one or more packets as a
result of the tune-away.
[0073] Some aspects, described herein, may enable tune-away
management. For example, in some aspects, described herein, a UE
may predict a tune-away for a set of voice frames, and may perform
a response action based at least in part on predicting the
tune-away. In this case, the response action may include altering a
vocoder rate, dropping a particular selected subset of packets,
enabling redundancy for a particular selected subset of packets,
signaling a channel aware mode to enable packet recovery, and/or
the like.
[0074] FIGS. 7A-7C are diagrams illustrating an example 700 of
tune-away management, in accordance with various aspects of the
present disclosure. As shown in FIG. 7A, example 700 may include a
UE 145, 250.
[0075] As further shown in FIG. 7A, UE 145, 250 may perform a VoLTE
call. For example, the VoLTE call may include a set of voice frames
702 (shown as voice frames 702-1 through 702-4). Each voice frame
702 may correspond to an IP packet 704 (shown as 704-1 through
704-4). In some aspects, UE 145, 250 may operate in an SPS mode.
For example, UE 145, 250 may receive a set of dynamic uplink grants
706 (shown as 706-1 through 706-4) and a set of periodic uplink
grants 708 (shown as 708-1 through 708-4). In some aspects, each IP
packet 704 may be scheduled for transmission using a corresponding
periodic uplink grant 708. UE 145, 250 may be scheduled for a page
monitoring period 710.
[0076] As further shown in FIG. 7A, and by reference number 712, UE
145, 250 may determine a predicted tune-away for a set of voice
frames. For example, UE 145, 250 may determine that page monitoring
period 710 is scheduled for a period concurrent with periodic
uplink grants 708-2 and 708-3. In this case, UE 145, 250 may
determine that page monitoring period 710 is predicted to cause a
tune-away from transmission of IP packets 704-2 and 704-3 to convey
voice frames 702-2 and 702-3, respectively. In some aspects, UE
145, 250 may determine that the predicted tune-away is to cause a
subset of packets of IP packets 704-1 through 704-4 to be dropped.
As shown by reference number 714, UE 145, 250 may determine that IP
packets 704-2 and 704-3 corresponding to periodic uplink grants
708-2 and 708-3, respectively, may be dropped as a result of a
tune-away in connection with page monitoring period 710.
[0077] In some aspects, UE 145, 250 may predict the tune-away based
at least in part on a schedule for a paging cycle. For example,
after a first tune-away, UE 145, 250 may predict a second tune-away
based at least in part on a start time of the first tune-away
and/or a configured duration for the paging cycle. In some aspects,
UE 145, 250 may determine the duration for the paging cycle. For
example, based at least in part on a duration between two or more
previous tune-aways, UE 145, 250 may determine a duration for one
or more upcoming tune-aways. In some aspects, UE 145, 250 may
predict the tune-away based at least in part on a cell change. For
example, based at least in part on a cell change, UE 145, 250 may
adjust a prediction for a timing of a predicted tune-away. In this
way, UE 145, 250 accounts for different timings associated with
different cells. In some aspects, UE 145, 250 may determine that a
call is a VoLTE call. For example, based at least in part on an IMS
call set up message or a radio bearer activation (e.g., a radio
bearer with a quality of service (QoS) Class Identifier (QCI) value
1), UE 145, 250 may determine that the call is a VoLTE call, which
may trigger UE 145, 250 to predict a tune-away.
[0078] As shown in FIG. 7B, and by reference number 716, as a
response action to determining the predicted tune-away, UE 145, 250
may alter a vocoder rate. For example, based at least in part on
determining the predicted tune-away for the VoLTE call, UE 145, 250
may alter the vocoder rate for at least one voice frame 702 from a
first vocoder rate to a second vocoder rate that is less than the
first vocoder rate. In some aspects, UE 145, 250 may determine a
subset of voice frames 702 for which to alter the vocoder rate. For
example, UE 145, 250 may alter the vocoder rate for a range of
voice frames 702 from a first voice frame 702 that may be affected
by the predicted tune-away (e.g., voice frame 702-2) to a last
voice frame 702 that may be affected by the predicted tune-away
(e.g., voice frame 702-3). In this case, UE 145, 250 may determine
a predicted duration of the predicted tune-away, such as a
predicted duration of two voice frames 702, to select the range of
voice frames 702 for which to alter the vocoder rate. As shown by
reference number 718, UE 145, 250 may determine a range that is
greater than a duration of the predicted tune-away, such as a range
from voice frame 702-2 to voice frame 702-4 to account for a
variability in the duration of the predicted tune-away, to reduce a
likelihood of prematurely returning to the first vocoder rate,
and/or the like.
[0079] In some aspects, UE 145, 250 may determine the second
vocoder rate based at least in part on an uplink bandwidth
allocation. For example, when UE 145, 250 determines that one or
more voice frames 702 are to be included in a single uplink
transmission (e.g., using a periodic uplink grant 708), UE 145, 250
may determine to reduce the vocoder rate r according to a ratio of
r=1/(D+1), where D represents a quantity of voice frames 702 that
are to be included in a single transmission. Additionally, or
alternatively, UE 145, 250 may determine a codec rate c, according
to c=R/[(D+1)(1+.alpha.)], where R represents a grant bandwidth
(e.g., of a periodic uplink grant 708), and a represents an
RTP/UDP/IP and LTE L2 overhead amount. In this case, UE 145, 250
may use an enhanced voice services (EVS) codec. In this way, as
shown by reference numbers 720 and 722, UE 145, 250 ensures that IP
packets 704-2 and 704-3 conveying voice frames 702-2 and 702-3,
respectively, can be included in an uplink transmission using
periodic uplink grant 708-4, thereby avoiding an interruption in
VoLTE service from the predicted tune-away associated with page
monitoring period 710. In this way, UE 145, 250 adjusts voice frame
processing adaptively to account for tune-aways, thereby reducing a
likelihood of an interruption to the VoLTE service relative to
maintaining a constant voice frame processing, and improving voice
frame quality relative to using a constant, reduced vocoder rate to
account for tune-aways.
[0080] As shown in FIG. 7C, and by reference number 724, as another
response action to the predicted tune-away, UE 145, 250 may drop a
subset of packets. For example, based at least in part on
determining the predicted tune-away, UE 145, 250 may select a
subset of packets, of IP packets 704-1 through 704-4, and may drop
the subset of packets. In this case, as shown by reference numbers
726 and 728, UE 145, 250 may drop IP packet 704-2 from transmission
using periodic uplink grant 708-2. In this way, UE 145, 250 may
avoid inadvertently dropping one or more other packets of IP
packets 704-1 through 704-4. Additionally, or alternatively, UE
145, 250 may drop one or more other IP packets 704-1 through 704-4
occurring before the period of the predicted tune-away, concurrent
with the period of the predicted tune-away, after the period of the
predicted, tune-away, and/or the like.
[0081] In some aspects, UE 145, 250 may drop the subset of packets
until uplink bandwidth is available to transport remaining packets.
As shown by reference number 728, based at least in part on
dropping IP packet 704-2, UE 145, 250 provides IP packet 704-3
using periodic uplink grant 708-4. Additionally, or alternatively,
UE 145, 250 may drop a quantity of packets to ensure that a size of
a transmission queue does not exceed a threshold size. In this way,
UE 145, 250 may maintain a threshold level of delay
performance.
[0082] In another example, UE 145, 250 may enable partial
redundancy as another response action to the predicted tune-away.
For example, based at least in part on determining the predicted
tune-away, UE 145, 250 may enable a channel aware mode to cover a
subset of voice frames 702 that are to be interrupted by the
tune-away, and may utilize subsequent periodic uplink grants 708 to
provide redundant data corresponding to the subset of voice frames
702. In this case, UE 145, 250 may drop one or more IP packets
704-1 through 704-4 corresponding to voice frames 702-1 through
702-4 that are to be interrupted by the tune-away.
[0083] In another example, UE 145, 250 may utilize partial
redundancy for avoidance of tune-away related disruptions in
downlink transmissions. For example, based at least in part on
determining a predicted tune-away in a channel unaware mode, UE
145, 250 may signal a base station (e.g., eNB 110, 210, 230) to
enable channel aware mode, and may receive subsequent downlink
transmissions in the channel aware mode to ensure redundancy for
the subsequent downlink transmissions. In this way, UE 145, 250
reduces a likelihood of an interruption to downlink data in
connection with a tune-away.
[0084] As indicated above, FIGS. 7A-7C are provided as examples.
Other examples are possible and may differ from what was described
with respect to FIGS. 7A-7C.
[0085] FIG. 8 is a diagram illustrating an example process 800
performed, for example, by a UE, in accordance with various aspects
of the present disclosure. Example process 800 is an example where
a UE (e.g., UE 145, 250) performs tune-away management.
[0086] As shown in FIG. 8, in some aspects, process 800 may include
determining a predicted tune-away for a set of voice frames (block
810). For example, UE 145, 250 may determine the predicted
tune-away for the set of voice frames.
[0087] As shown in FIG. 8, in some aspects, process 800 may include
altering a vocoder rate from a first vocoder rate to a second
vocoder rate that is less than the first vocoder rate based at
least in part on determining the predicted tune-away for the set of
voice frames (block 820). For example, based at least in part on
determining the predicted tune-away for the set of voice frames, UE
145, 250 may alter the vocoder rate from the first vocoder rate to
the second vocoder rate. In this case, the second vocoder rate may
be less than the first vocoder rate.
[0088] Additionally, or alternatively, the second vocoder rate may
be determined based at least in part on an uplink bandwidth
allocation.
[0089] Additionally, or alternatively, the second vocoder rate may
be determined based at least in part on a bandwidth grant.
[0090] Additionally, or alternatively, the second vocoder rate may
be determined based at least in part on an overhead
characteristic.
[0091] Additionally, or alternatively, the second vocoder rate may
be determined based at least in part on the first vocoder rate.
[0092] Additionally, or alternatively, the predicted tune-away may
be determined based at least in part on a paging cycle and a
tune-away start time.
[0093] Additionally, or alternatively, a tune-away duration for the
predicted tune-away may be determined based at least in part on
stored information identifying at least one previous tune-away
duration.
[0094] Additionally, or alternatively, the predicted tune-away may
be determined based at least in part on a cell change.
[0095] Although FIG. 8 shows example blocks of process 800, in some
aspects, process 800 may include additional blocks, fewer blocks,
different blocks, or differently arranged blocks than those
depicted in FIG. 8. Additionally, or alternatively, two or more of
the blocks of process 800 may be performed in parallel.
[0096] FIG. 9 is a diagram illustrating an example process 900
performed, for example, by a UE, in accordance with various aspects
of the present disclosure. Example process 900 is an example where
a UE (e.g., UE 145, 250) performs tune-away management.
[0097] As shown in FIG. 9, in some aspects, process 900 may include
determining a predicted tune-away for a set of voice frames (block
910). For example, UE 145, 250 may determine the predicted
tune-away for the set of voice frames.
[0098] As shown in FIG. 9, in some aspects, process 900 may include
dropping, in connection with an occurrence of the predicted
tune-away, a subset of packets for a time period corresponding to
the predicted tune-away (block 920). For example, based at least in
part on determining the predicted tune-away, UE 145, 250 may drop,
in connection with the occurrence of the predicted tune-away, the
subset of packets for the time period corresponding to the
predicted tune-away.
[0099] Additionally, or alternatively, at least one packet,
occurring during the time period corresponding to the predicted
tune-away, may be transmitted after the time period corresponding
to the predicted tune-away.
[0100] Additionally, or alternatively, a quantity of packets to be
dropped as the subset of packets may be determined based at least
in part on a transmission queue parameter.
[0101] Additionally, or alternatively, UE 145, 250 may transmit,
using an enhanced voice services (EVS) codec, redundant data for
packets occurring during the time period corresponding to the
predicted tune-away.
[0102] Additionally, or alternatively, the user equipment is
operating in a channel aware mode.
[0103] Additionally, or alternatively, a channel aware mode may be
activated for the time period corresponding to the predicted
tune-away and deactivated after the time period corresponding to
the predicted tune-away.
[0104] Additionally, or alternatively, UE 145, 250 may receive
redundant data for packets occurring during the time period
corresponding to the predicted tune-away.
[0105] Additionally, or alternatively, activation of a channel
aware mode may be signaled using in-band signaling or a real-time
transport protocol control protocol message.
[0106] Although FIG. 9 shows example blocks of process 900, in some
aspects, process 900 may include additional blocks, fewer blocks,
different blocks, or differently arranged blocks than those
depicted in FIG. 9. Additionally, or alternatively, two or more of
the blocks of process 900 may be performed in parallel.
[0107] The foregoing disclosure provides illustration and
description, but is not intended to be exhaustive or to limit the
aspects to the precise form disclosed. Modifications and variations
are possible in light of the above disclosure or may be acquired
from practice of the aspects.
[0108] As used herein, the term component is intended to be broadly
construed as hardware, firmware, or a combination of hardware and
software. As used herein, a processor is implemented in hardware,
firmware, or a combination of hardware and software.
[0109] Some aspects are described herein in connection with
thresholds. As used herein, satisfying a threshold may refer to a
value being greater than the threshold, greater than or equal to
the threshold, less than the threshold, less than or equal to the
threshold, equal to the threshold, not equal to the threshold,
and/or the like.
[0110] It will be apparent that systems and/or methods, described
herein, may be implemented in different forms of hardware,
firmware, or a combination of hardware and software. The actual
specialized control hardware or software code used to implement
these systems and/or methods is not limiting of the aspects. Thus,
the operation and behavior of the systems and/or methods were
described herein without reference to specific software code--it
being understood that software and hardware can be designed to
implement the systems and/or methods based, at least in part, on
the description herein.
[0111] Even though particular combinations of features are recited
in the claims and/or disclosed in the specification, these
combinations are not intended to limit the disclosure of possible
aspects. In fact, many of these features may be combined in ways
not specifically recited in the claims and/or disclosed in the
specification. Although each dependent claim listed below may
directly depend on only one claim, the disclosure of possible
aspects includes each dependent claim in combination with every
other claim in the claim set. 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).
[0112] No element, act, or instruction used herein should be
construed as critical or essential unless explicitly described as
such. Also, as used herein, the articles "a" and "an" are intended
to include one or more items, and may be used interchangeably with
"one or more." Furthermore, as used herein, the terms "set" and
"group" are intended to include one or more items (e.g., related
items, unrelated items, a combination of related and unrelated
items, and/or the like), and may be used interchangeably with "one
or more." Where only one item is intended, the term "one" or
similar language is used. Also, as used herein, the terms "has,"
"have," "having," and/or the like are intended to be open-ended
terms. Further, the phrase "based on" is intended to mean "based,
at least in part, on" unless explicitly stated otherwise.
* * * * *