U.S. patent application number 17/325844 was filed with the patent office on 2021-09-02 for soft discontinuous reception (soft drx).
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Akram Bin Sediq.
Application Number | 20210274589 17/325844 |
Document ID | / |
Family ID | 1000005599433 |
Filed Date | 2021-09-02 |
United States Patent
Application |
20210274589 |
Kind Code |
A1 |
Bin Sediq; Akram |
September 2, 2021 |
SOFT DISCONTINUOUS RECEPTION (SOFT DRX)
Abstract
Embodiments of the present disclosure are related to achieving
better tradeoffs between battery saving and latency to, e.g.,
support ultra-low latency applications by introducing soft
Discontinuous Reception (DRX). In some embodiments, a method of
operation of a node in a wireless communications network comprises
initiating transmission, during a DRX awake period, of control
information to a wireless device on two or more control channel
subsets during two or more time periods within the DRX awake
period, respectively. The two or more control channel subsets are
different subsets of a plurality of candidate control channels. In
some embodiments, the two or more time periods are two or more
subframes. The candidate control channels are control channels that
the wireless device is configured to monitor. The two or more
control channel subsets can be selected to, e.g., reduce latency
while not increasing energy consumption as compared to legacy
DRX.
Inventors: |
Bin Sediq; Akram; (Kanata,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
1000005599433 |
Appl. No.: |
17/325844 |
Filed: |
May 20, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16310365 |
Dec 14, 2018 |
11051356 |
|
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PCT/IB2016/053623 |
Jun 17, 2016 |
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17325844 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/0216 20130101;
H04W 76/28 20180201; H04W 72/042 20130101; H04L 5/0007
20130101 |
International
Class: |
H04W 76/28 20060101
H04W076/28; H04W 52/02 20060101 H04W052/02; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method of operation of a node in a wireless communications
network, the method comprising: initiating transmission, during a
Discontinuous Reception (DRX) awake period of a wireless device, of
control information to the wireless device in a time period within
the DRX awake period of the wireless device on one or more control
channels from one of at least two control channel subsets, wherein
the at least two control channel subsets are at least two different
subsets of a plurality of candidate control channels that are
configured for the wireless device for at least two time periods
within the DRX awake period of the wireless device,
respectively.
2. The method of claim 1, wherein the at least two time periods are
two or more subframes.
3. The method of claim 1, wherein: the plurality of candidate
control channels comprises a first plurality of candidate Physical
Downlink Control Channels (PDCCHs) and a second plurality of
candidate enhanced PDCCHs (ePDCCHs); and the at least two control
channel subsets comprise: a first control channel subset that
comprises at least some of the first plurality of candidate PDCCHs
but not any of the second plurality of candidate ePDCCHs; and a
second control channel subset that comprises at least some of the
second plurality of candidate ePDCCHs but not any of the first
plurality of candidate PDCCHs.
4. The method of claim 1, wherein the at least two control channel
subsets consist of two control channel subsets.
5. The method of claim 1, wherein the at least two control channel
subsets comprise a first control channel subset that comprises all
of the plurality of candidate control channels and a second control
channel subset that comprises less than all of the plurality of
candidate control channels.
6. The method of claim 1, wherein initiating the transmission of
the control information to the wireless device in the time period
within the DRX awake period of the wireless device on said one or
more control channels in the one of the at least two control
channel subsets comprises: determining a first control channel
subset for a first time period within the DRX awake period of the
wireless device; initiating the transmission of the control
information to the wireless device in one or more candidate control
channels in the first control channel subset during the first time
period if the wireless device is scheduled in the first time
period; determining a second control channel subset for a second
time period within the DRX awake period of the wireless device; and
initiating the transmission of the control information to the
wireless device in one or more candidate control channels in the
second control channel subset during the second time period if the
wireless device is scheduled in the second time period.
7. The method of claim 1, further comprising: initiating
transmission of one or more soft DRX parameters to the wireless
device, the one or more soft DRX parameters comprising information
that defines the at least two control channel subsets for the at
least two time periods within the DRX awake period,
respectively.
8. A node for operation in a wireless communications network, the
node comprising: at least one processor; and memory storing
instructions executable by the at least one processor whereby the
node is operable to: initiate transmission, during a Discontinuous
Reception (DRX) awake period of a wireless device, of control
information to the wireless device in a time period within the DRX
awake period of the wireless device on one or more control channels
from one of at least two control channel subsets, wherein the at
least two control channel subsets are at least two different
subsets of a plurality of candidate control channels that are
configured for the wireless device for at least two time periods
within the DRX awake period of the wireless device,
respectively.
9. The node of claim 8, wherein the at least two time periods are
two or more subframes.
10. The node of claim 8, wherein: the plurality of candidate
control channels comprises a first plurality of candidate Physical
Downlink Control Channels (PDCCHs) and a second plurality of
candidate enhanced PDCCHs (ePDCCHs); and the at least two control
channel subsets comprise: a first control channel subset that
comprises at least some of the first plurality of candidate PDCCHs
but not any of the second plurality of candidate ePDCCHs; and a
second control channel subset that comprises at least some of the
second plurality of candidate ePDCCHs but not any of the first
plurality of candidate PDCCHs.
11. The node of claim 8, wherein the at least two control channel
subsets consist of two control channel subsets.
12. The node of claim 8, wherein the at least two control channel
subsets comprise a first control channel subset that comprises all
of the plurality of candidate control channels and a second control
channel subset that comprises less than all of the plurality of
candidate control channels.
13. The node of claim 8, wherein to initiate the transmission of
the control information to the wireless device in the time period
within the DRX awake period of the wireless device on said one or
more control channels in the one of the at least two control
channel subsets, the node is further operable to: determine a first
control channel subset for a first time period within the DRX awake
period of the wireless device; initiate the transmission of the
control information to the wireless device in one or more candidate
control channels in the first control channel subset during the
first time period if the wireless device is scheduled in the first
time period; determine a second control channel subset for a second
time period within the DRX awake period of the wireless device; and
initiate the transmission of the control information to the
wireless device in one or more candidate control channels in the
second control channel subset during the second time period if the
wireless device is scheduled in the second time period.
14. The node of claim 8, further operable to: initiate transmission
of one or more soft DRX parameters to the wireless device, the one
or more soft DRX parameters comprising information that defines the
at least two control channel subsets for the at least two time
periods within the DRX awake period, respectively.
15. A non-transitory computer-readable storage medium comprising
instructions for operation of a node in a wireless communications
network, wherein the instructions, upon execution by a processor of
the node, cause the node to: initiate transmission, during a
Discontinuous Reception (DRX) awake period of a wireless device, of
control information to the wireless device in a time period within
the DRX awake period of the wireless device on one or more control
channels from one of at least two control channel subsets, wherein
the at least two control channel subsets are at least two different
subsets of a plurality of candidate control channels that are
configured for the wireless device for at least two time periods
within the DRX awake period of the wireless device,
respectively.
16. The non-transitory computer-readable storage medium of claim
15, wherein the instructions further cause the node to limit the
transmission of the control information to the wireless device on
control channels of the one or more control channels that are being
monitored by the wireless device.
17. The non-transitory computer-readable storage medium of claim
15, wherein the at least two time periods are two or more
subframes.
18. The non-transitory computer-readable storage medium of claim
15, wherein the at least two control channel subsets consist of two
control channel subsets.
19. The non-transitory computer-readable storage medium of claim
15, wherein the at least two control channel subsets comprise a
first control channel subset that comprises all of the plurality of
candidate control channels and a second control channel subset that
comprises less than all of the plurality of candidate control
channels.
20. The non-transitory computer-readable storage medium of claim
15, wherein to initiate the transmission of the control information
to the wireless device in the time period within the DRX awake
period of the wireless device on said one or more control channels
in the one of the at least two control channel subsets, the
instructions further cause the node to: determine a first control
channel subset for a first time period within the DRX awake period
of the wireless device; initiate the transmission of the control
information to the wireless device in one or more candidate control
channels in the first control channel subset during the first time
period if the wireless device is scheduled in the first time
period; determine a second control channel subset for a second time
period within the DRX awake period of the wireless device; and
initiate the transmission of the control information to the
wireless device in one or more candidate control channels in the
second control channel subset during the second time period if the
wireless device is scheduled in the second time period.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. patent
application Ser. No. 16/310,365, filed on Dec. 14, 2018, which is a
National Stage Entry of PCT International Application No.
PCT/IB2016/053623, filed on Jun. 17, 2016, the disclosure and
content of each of which are incorporated herein by reference in
their entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to Discontinuous Reception
(DRX) in a wireless communications network.
BACKGROUND
[0003] For the sake of presentation, the technical background is
explained with respect to cellular networks that are implemented
based on Long Term Evolution (LTE) and LTE-Advanced standards, both
of which are generally referred to herein as LTE. Nevertheless, the
present disclosure is generally applicable to any wireless
communication network or any cellular communication network in
which the wireless device supports Discontinuous Reception
(DRX).
LTE Frame Structure
[0004] Orthogonal Frequency Division Multiplexing (OFDM) is used in
LTE, where the radio resources are divided into OFDM symbols in the
time domain and orthogonal narrowband sub-carriers in the frequency
domain. The smallest radio frequency element in LTE resources is
called a Resource Element (RE). A RE consists of one OFDM symbol in
time that spans 66.7 microseconds (.mu.s) plus a normal or extended
cycle prefix and one sub-carrier in frequency that spans 15
kilohertz (kHz). A RE can carry one modulation symbol. The smallest
unit that can be scheduled to a User Equipment device (UE) is
defined as a Physical Resource Block (PRB) pair, which consists of
12 subcarriers in frequency and two slots in time, where each slot
consists of six to seven OFDM symbols. A PRB pair spans one
subframe in time, which has a duration of 1 millisecond (ms).
[0005] In LTE, the base station, called an enhanced or evolved Node
B (eNB), schedules downlink transmissions to UEs on a per-subframe
basis. In addition to transmitting the UE traffic data, the eNB
needs to transmit Downlink Control Information (DCI) to UEs, which
includes information about the location of the PRB pairs allocated
to the UEs in the Physical Downlink Shared Channel (PDSCH), the
type of modulation and coding that the UEs need to use for decoding
the UEs' traffic data, as well as other control information. In LTE
Release 8, 9, and 10, DCI is conveyed only in a Physical Downlink
Control Channel (PDCCH). A PDCCH is transmitted in the control
region of the subframe, which is located at the beginning of the
subframe (up to the first four OFDM symbols). In LTE Release 11, an
enhanced PDCCH (ePDCCH) is introduced as described in Third
Generation Partnership Project (3GPP) Technical Specification (TS)
36.211 V12.4.0, Section 6.8A, where DCI can also be transmitted in
the data region of the subframe that carries the data traffic for
UEs.
[0006] Since the UE does not know a priori whether it is scheduled
in a particular subframe or not, the UE monitors the eNB downlink
transmission. Since the UE does not know the precise location
within the subframe of the DCI intended for the UE, the UE performs
blind decoding, where the UE monitors all control channel
candidates that may be assigned to the UE in the subframe. These
control channel candidates are referred to as PDCCH candidates (or
ePDCCH candidates), and the UE may receive DCI on any of the PDCCH
candidates (or ePDCCH candidates).
Discontinuous Reception
[0007] The UE is required to monitor its serving eNB's transmission
in order to know if there is downlink data intended for the UE.
However, continuously monitoring the downlink channel results in
high energy consumption, which reduces the battery lifetime of the
UE. In order to reduce energy consumption, Discontinuous Reception
(DRX) is implemented where the UE goes into predefined Awake/Sleep
periods to save battery life. As used herein, the "DRX awake
period" is a period of time during which a wireless device
operating according to a DRX scheme is awake during a DRX cycle. In
3GPP LTE, the DRX awake period includes one or more of the
following: On Duration Timer for long and short cycle, DRX
Inactivity Timer, and DRX Retransmission Timer, which are defined
in 3GPP TS 36.321 V12.4.0 in Section 3.1, as follows: [0008] On
Duration Timer: the number of consecutive PDCCH subframe(s) where
the UE is Awake at the beginning of a DRX cycle, whether it is a
long DRX cycle or a DRX short cycle, as shown in FIG. 1. [0009] DRX
Inactivity Timer: the number of consecutive PDCCH subframe(s) where
the UE is Awake after the subframe within which a PDCCH indicates
an initial uplink or downlink user data transmission. Upon expiry
of DRX Inactivity Timer and if short DRX cycle is configured, short
DRX cycle is used and DRX Short Cycle Timer specifies the number of
consecutive subframe(s) where the short DRX cycle is followed.
[0010] DRX Retransmission Timer: when a retransmission is expected,
this parameter denotes the number of consecutive PDCCH-subframe(s)
where the UE is Awake until a downlink retransmission is
received.
[0011] The Awake state can be sometimes extended longer than the On
Duration Timer. For example, the Awake state may be extended longer
than the On Duration Timer shown in FIG. 1 due to the detection of
initial uplink or downlink transmission which activate DRX
Inactivity Timer, due to the activation of short cycle if
configured, due to the expectation of possible retransmission which
may activate DRX Retransmission Timer, and/or during contention
resolution in random access. When the UE is in the Awake state, the
UE decodes all control channel candidates to determine whether
there is data for the UE. For instance, for an LTE UE configured
with PDCCH, the UE is expected to monitor a total of 22 PDCCH
candidates (i.e., sum of numbers in the last column in Table 1
below) in every subframe where the UE is in the Awake state. The
time-frequency locations of the 22 PDCCH candidates are dependent
on a Radio Network Temporary Identifier (RNTI) and the subframe
number; however, the number of PDCCH candidates that the UE monitor
is the same (i.e., 22) in every subframe during a DRX Awake period.
On the other hand, when the UE is in the Sleep state, the UE does
not monitor or decode any channel, i.e., the UE goes to sleep to
save battery.
TABLE-US-00001 TABLE 1 PDCCH candidates monitored by a UE
(reproduced from 3GPP TS 36.213 V12.4.0, Table 9.1.1-1). Search
space S.sub.k.sup.(L) Number Aggregation Size of PDCCH Type level L
[in CCEs] candidates M.sup.(L) UE-specific 1 6 6 2 12 6 4 8 2 8 16
2 Common 4 16 4 8 16 2
[0012] The battery gain achieved by using DRX comes at the expense
of increased downlink latency, as transmission of packets that
arrive at the eNB when the UE is in the Sleep state has to wait
until the UE is in the Awake state. For instance, the DRX long
cycle may be 320 ms and the ON Duration Timer may be 10 ms. This
results in a latency of up to 310 ms for a packet that arrives at
the eNB when the UE is in the Sleep state. Such latency may not be
acceptable for ultra-low latency applications that are expected to
be supported in next generation networks such as healthcare and
emergency notification systems.
SUMMARY
[0013] Embodiments of the present disclosure are related to
achieving better tradeoffs between battery saving and latency to,
e.g., support ultra-low latency applications by introducing soft
Discontinuous Reception (DRX). In some embodiments, a method of
operation of a wireless device in a wireless communications network
comprises monitoring, during a DRX awake period, two or more
control channel subsets during two or more time periods within the
DRX awake period, respectively. The two or more control channel
subsets are different subsets of a plurality of candidate control
channels. In some embodiments, the two or more time periods are two
or more subframes. The candidate control channels are control
channels that the wireless device is configured to monitor. The two
or more control channel subsets can be selected to, e.g., reduce
latency while not increasing energy consumption as compared to
legacy DRX.
[0014] In some embodiments, the wireless device supports downlink
Carrier Aggregation (CA), and the plurality of candidate control
channels comprise candidate control channels on at least two
downlink carriers. In some embodiments, a first control channel
subset of the two or more control channel subsets comprises at
least one candidate control channel on a first carrier of the at
least two downlink carriers but not any candidate control channels
on a second carrier of the at least two downlink carriers.
[0015] In some embodiments, the plurality of candidate control
channels comprises a first plurality of candidate Physical Downlink
Control Channels (PDCCHs) and a second plurality of candidate
enhanced PDCCHs (ePDCCHs). Further, the two or more control channel
subsets comprise a first control channel subset that comprises at
least some of the first plurality of candidate PDCCHs but not any
of the second plurality of candidate ePDCCHs, and a second control
channel subset that comprises at least some of the second plurality
of candidate ePDCCHs but not any of the first plurality of
candidate PDCCHs.
[0016] In some embodiments, at least one of the two or more control
channel subsets comprises one or more candidate control channels
that utilize a low complexity modulation and coding scheme. In some
embodiments, the one or more candidate control channels that
utilize a low complexity modulation and coding scheme are candidate
control channels that utilize a modulation and coding scheme that
is sufficient to carry only data to enable the wireless device to
activate a DRX Inactivity Timer or to switch to legacy DRX.
[0017] In some embodiments, the two or more control channel subsets
consist of two control channel subsets.
[0018] In some embodiments, the two or more control channel subsets
comprise a first control channel subset that comprises all of the
plurality of candidate control channels and a second control
channel subset that comprises less than all of the plurality of
candidate control channels.
[0019] In some embodiments, monitoring the two or more control
channel subsets during the two or more time periods within the DRX
awake period, respectively, comprises determining a first control
channel subset for a first time period within the DRX awake period,
monitoring candidate control channels in the first control channel
subset during the first time period for a downlink control channel
transmission to the wireless device, determining a second control
channel subset for a second time period within the DRX awake
period, and monitoring candidate control channels in the second
control channel subset during the second time period for a downlink
control channel transmission to the wireless device.
[0020] In some embodiments, the method further comprises receiving
one or more soft DRX parameters from a network node, the one or
more soft DRX parameters comprising information that defines the
two or more control channel subsets for the two or more time
periods within the DRX awake period, respectively. In some
embodiments, receiving the one or more soft DRX parameters from the
network node comprises receiving a Radio Resource Control (RRC)
message from the network node comprising the one or more soft DRX
parameters. In some embodiments, the method further comprises
sending capability information to the network node, the capability
information comprising an indication of whether the wireless device
supports soft DRX. In some embodiments, receiving the one or more
soft DRX parameters from the network node comprises receiving a
Medium Access Control (MAC) Control Element (CE) from the network
node comprising the one or more soft DRX parameters. In some
embodiments, the method further comprises deciding to accept soft
DRX activation upon receiving the MAC CE, and sending an acceptance
of soft DRX activation to the network node.
[0021] In some embodiments, the method further comprises sending a
message to activate soft DRX to a network node, and receiving a
response from the network node. In some embodiments, the message to
activate soft DRX comprises one or more soft DRX parameters
comprising information that defines the two or more control channel
subsets for the two or more time periods within the DRX awake
period, respectively. In some embodiments, the message to activate
soft DRX comprises one or more modifications to one or more soft
DRX parameters comprising information that defines the two or more
control channel subsets for the two or more time periods within the
DRX awake period, respectively.
[0022] In some embodiments, a DRX offset for the wireless device is
different than a DRX offset of another wireless device such that at
least one of the two or more time periods within the DRX awake
period of the wireless device does not overlap with at least one
respective time period within a DRX awake period of the other
wireless device.
[0023] In some embodiments, the method further comprises sending a
request to deactivate soft DRX to a network node.
[0024] In some embodiments, the method further comprises
deactivating soft DRX in response to an occurrence of an external
or internal event.
[0025] In some embodiments, the method further comprises receiving
a request to deactivate soft DRX from a network node.
[0026] Embodiments of a wireless device for operation in a wireless
communications network are also disclosed. In some embodiments, the
wireless device is adapted to monitor, during a DRX awake period,
two or more control channel subsets during two or more time periods
within the DRX awake period, respectively, wherein the two or more
control channel subsets are different subsets of a plurality of
candidate control channels. In some embodiments, the wireless
device is further adapted to operate according to any embodiment of
the method of operation of a wireless device disclosed herein.
[0027] In some embodiments, a wireless device for operation in a
wireless communications network comprises at least one transceiver,
at least one processor, and memory storing instructions executable
by the at least one processor whereby the wireless device is
operable to monitor, during a DRX awake period, two or more control
channel subsets during two or more time periods within the DRX
awake period, respectively, wherein the two or more control channel
subsets are different subsets of a plurality of candidate control
channels. In some embodiments, the wireless device is further
adapted to operate according to any embodiment of the method of
operation of a wireless device disclosed herein.
[0028] In some embodiments, a wireless device for operation in a
wireless communications network comprises a monitoring module
operable to monitor, during a DRX awake period, two or more control
channel subsets during two or more time periods within the DRX
awake period, respectively, wherein the two or more control channel
subsets are different subsets of a plurality of candidate control
channels. In some embodiments, the wireless device further
comprises one or more additional modules operable to cause the
wireless device to operate according to any embodiment of the
method of operation of a wireless device disclosed herein.
[0029] Embodiments of a method of operation of a node in a wireless
communications network are also disclosed. In some embodiments, the
method of operation of the node comprises initiating transmission,
during a DRX awake period of a wireless device, of control
information to the wireless device in a time period within the DRX
awake period of the wireless device on one or more control channels
in one of at least two control channel subsets. The at least two
control channel subsets are at least two different subsets of a
plurality of candidate control channels that are configured for the
wireless device for at least two time periods within the DRX awake
period of the wireless device, respectively. In some embodiments,
the two or more time periods are two or more subframes.
[0030] In some embodiments, the plurality of candidate control
channels comprises candidate control channels on at least two
downlink carriers. In some embodiments, a first control channel
subset of the two or more control channel subsets comprises at
least one candidate control channel on a first carrier of the at
least two downlink carriers but not any candidate control channels
on a second carrier of the at least two downlink carriers.
[0031] In some embodiments, the plurality of candidate control
channels comprises a first plurality of candidate PDCCHs, and a
second plurality of candidate ePDCCHs. Further, the two or more
control channel subsets comprise a first control channel subset
that comprises at least some of the first plurality of candidate
PDCCHs but not any of the second plurality of candidate ePDCCHs,
and a second control channel subset that comprises at least some of
the second plurality of candidate ePDCCHs but not any of the first
plurality of candidate PDCCHs.
[0032] In some embodiments, at least one of the two or more control
channel subsets comprises one or more candidate control channels
that utilize a low complexity modulation and coding scheme. In some
embodiments, the one or more candidate control channels that
utilize a low complexity modulation and coding scheme are candidate
control channels that utilize a modulation and coding scheme that
is sufficient to carry only data to enable the wireless device to
activate a DRX Inactivity Timer or to switch to legacy DRX.
[0033] In some embodiments, the two or more control channel subsets
consist of two control channel subsets.
[0034] In some embodiments, the two or more control channel subsets
comprise a first control channel subset that comprises all of the
plurality of candidate control channels and a second control
channel subset that comprises less than all of the plurality of
candidate control channels.
[0035] In some embodiments, initiating transmission of control
information to the wireless device in the time period within the
DRX awake period of the wireless device on one or more control
channels in the one of at least two control channel subsets
comprises determining a first control channel subset for a first
time period within the DRX awake period of the wireless device,
initiating transmission of control information to the wireless
device in one or more candidate control channels in the first
control channel subset during the first time period if the wireless
device is scheduled in the first time period, determining a second
control channel subset for a second time period within the DRX
awake period of the wireless device, and initiating transmission of
control information to the wireless device in one or more candidate
control channels in the second control channel subset during the
second time period if the wireless device is scheduled in the
second time period.
[0036] In some embodiments, the method further comprises initiating
transmission of one or more soft DRX parameters to the wireless
device, the one or more soft DRX parameters comprising information
that defines the two or more control channel subsets for the two or
more time periods within the DRX awake period, respectively. In
some embodiments, initiating transmission of the one or more soft
DRX parameters to the wireless device comprises initiating
transmission of a RRC message to the wireless device comprising the
one or more soft DRX parameters. In some embodiments, the method
further comprises receiving capability information of the wireless
device where the capability information comprises an indication of
whether the wireless device supports soft DRX, and deciding whether
to activate soft DRX for the wireless device based on the
capability information of the wireless device. In some embodiments,
initiating transmission of the one or more soft DRX parameters to
the wireless device comprises initiating transmission of a MAC CE
to the wireless device comprising the one or more soft DRX
parameters.
[0037] In some embodiments, the method further comprises receiving
a message to activate soft DRX from the wireless device, deciding
whether to accept activation of soft DRX, and initiating
transmission of a response to the wireless device. In some
embodiments, the message to activate soft DRX comprises one or more
soft DRX parameters comprising information that defines the two or
more control channel subsets for the two or more time periods
within the DRX awake period, respectively. In some embodiments, the
message to activate soft DRX comprises one or more modification to
one or more soft DRX parameters comprising information that defines
the two or more control channel subsets for the two or more time
periods within the DRX awake period, respectively.
[0038] In some embodiments, a DRX offset for the wireless device is
different than a DRX offset of another wireless device such that at
least one of the two or more time periods within the DRX awake
period of the wireless device does not overlap with at least one
respective time period within a DRX awake period of the other
wireless device.
[0039] In some embodiments, the method further comprises receiving
a request to deactivate soft DRX from the wireless device.
[0040] In some embodiments, the method further comprises initiating
transmission of a request to deactivate soft DRX to the wireless
device.
[0041] Embodiments of a node for operation in a wireless
communications network are also disclosed. In some embodiments, the
node is adapted to initiate transmission, during a DRX awake period
of a wireless device, of control information to the wireless device
in a time period within the DRX awake period of the wireless device
on one or more control channels in one of at least two control
channel subsets. The at least two control channel subsets are at
least two different subsets of a plurality of candidate control
channels that are configured for the wireless device for at least
two time periods within the DRX awake period of the wireless
device, respectively. In some embodiments, the node is further
adapted to operate according to any embodiment of a method of
operation of a node disclosed herein.
[0042] In some embodiments, a node for operation in a wireless
communications network comprises at least one processor and memory
storing instructions executable by the at least one processor
whereby the node is operable to initiate transmission, during a DRX
awake period of a wireless device, of control information to the
wireless device in a time period within the DRX awake period of the
wireless device on one or more control channels in one of at least
two control channel subsets. The at least two control channel
subsets are at least two different subsets of a plurality of
candidate control channels that are configured for the wireless
device for at least two time periods within the DRX awake period of
the wireless device, respectively. In some embodiments, the node is
further adapted to operate according to any embodiment of a method
of operation of a node disclosed herein.
[0043] In some embodiments, a node for operation in a wireless
communications network comprises a transmission module operable to
initiate transmission, during a DRX awake period of a wireless
device, of control information to the wireless device in a time
period within the DRX awake period of the wireless device on one or
more control channels in one of at least two control channel
subsets. The at least two control channel subsets are at least two
different subsets of a plurality of candidate control channels that
are configured for the wireless device for at least two time
periods within the DRX awake period of the wireless device,
respectively. In some embodiments, the node further comprises one
or more additional modules operable to cause the node to operate
according to any embodiment of the method of operation of a node
disclosed herein.
[0044] Those skilled in the art will appreciate the scope of the
present disclosure and realize additional aspects thereof after
reading the following detailed description of the embodiments in
association with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The accompanying drawing figures incorporated in and forming
a part of this specification illustrate several aspects of the
disclosure, and together with the description serve to explain the
principles of the disclosure.
[0046] FIG. 1 illustrates an implementation of Discontinuous
Reception (DRX) in which a wireless device goes into cycles of
predefined Awake/Sleep durations;
[0047] FIGS. 2A and 2B show legacy DRX and an example of soft DRX,
respectively;
[0048] FIG. 3 illustrates one example of a wireless communications
network in which embodiments of the present disclosure may be
implemented;
[0049] FIG. 4 illustrates the operation of a wireless device and a
base station according to some embodiments of the present
disclosure;
[0050] FIG. 5 illustrates one example in which soft DRX is enabled,
or activated, via, e.g., Radio Resource Control (RRC) signaling
according to some embodiments of the present disclosure;
[0051] FIG. 6 illustrates one example in which soft DRX is enabled,
or activated, via, e.g., Medium Access Control (MAC) signaling
according to some embodiments of the present disclosure;
[0052] FIG. 7 illustrates another example in which soft DRX is
enabled, or activated, via, e.g., MAC signaling according to some
embodiments of the present disclosure;
[0053] FIG. 8 is a flow chart that illustrates a process performed
by a base station according to some embodiments of the present
disclosure;
[0054] FIG. 9 is a flow chart that illustrates a process performed
by a wireless device according to some embodiments of the present
disclosure;
[0055] FIG. 10 illustrates a plot of all feasible values of n.sub.1
(the number of subframes where the wireless device is Awake and it
is expected to monitor a first control channel subset using soft
DRX) and n.sub.2 (number of subframes where the wireless device is
Awake and it is expected to monitor the second control channel
subset using soft DRX) that satisfy two constraints according to
some example embodiments of the present disclosure;
[0056] FIGS. 11A and 11B provide an illustration of the soft DRX
profile compared to legacy DRX profile for an example in which
n.sub.1=5 and n.sub.2=10;
[0057] FIGS. 12A and 12B show the soft DRX profiles of two wireless
devices, assuming that both wireless devices use the soft DRX
profile shown in FIG. 11B;
[0058] FIGS. 13 and 14 are block diagrams of example embodiments of
a wireless device; and
[0059] FIGS. 15 to 17 are block diagrams of example embodiments of
a network node.
DETAILED DESCRIPTION
[0060] The embodiments set forth below represent information to
enable those skilled in the art to practice the embodiments and
illustrate the best mode of practicing the embodiments. Upon
reading the following description in light of the accompanying
drawing figures, those skilled in the art will understand the
concepts of the disclosure and will recognize applications of these
concepts not particularly addressed herein. It should be understood
that these concepts and applications fall within the scope of the
disclosure and the accompanying claims.
[0061] Radio Node: As used herein, a "radio node" is either a radio
access node or a wireless device.
[0062] Radio Access Node: As used herein, a "radio access node" is
any node in a radio access network of a wireless communications
network that operates to wirelessly transmit and/or receive
signals. Some examples of a radio access node include, but are not
limited to, a base station (e.g., an enhanced or evolved Node B
(eNB) in a Third Generation Partnership Project (3GPP) Long Term
Evolution (LTE) network), a high-power or macro base station, a
low-power base station (e.g., a micro base station, a pico base
station, a home eNB, or the like), and a relay node.
[0063] Core Network Node: As used herein, a "core network node" is
any type of node in a core network. Some examples of a core network
node include, but are not limited to, e.g., a Mobility Management
Entity (MME), a Packet Data Network (PDN) Gateway (P-GW), a Service
Capability Exposure Function (SCEF), or the like.
[0064] Wireless Device: As used herein, a "wireless device" is any
type of device that has access to (i.e., is served by) a wireless
communications network by wirelessly transmitting and/or receiving
signals to a radio access node(s). Some examples of a wireless
device include, but are not limited to, a User Equipment device
(UE) in a 3GPP network and a Machine Type Communication (MTC)
device.
[0065] Network Node: As used herein, a "network node" is any node
that is either part of the radio access network or the core network
of a wireless communications network/system.
[0066] Note that the description given herein focuses on a 3GPP
wireless communications system and, as such, 3GPP LTE terminology
or terminology similar to 3GPP LTE terminology is oftentimes used.
However, the concepts disclosed herein are not limited to LTE or a
3GPP system.
[0067] Note that, in the description herein, reference may be made
to the term "cell;" however, particularly with respect to Fifth
Generation (5G) concepts, beams may be used instead of cells and,
as such, it is important to note that the concepts described herein
are equally applicable to both cells and beams.
[0068] Legacy Discontinuous Reception (DRX): A technique where a
wireless device can monitor its control channel candidates
discontinuously based on predefined Awake/Sleep periods.
[0069] Soft DRX: As used herein, "soft DRX" is a DRX technique in
which a wireless device monitors, during a DRX awake period, two or
more control channel subsets during two or more time periods within
the DRX awake period, respectively. The two or more control channel
subsets are different subsets of multiple candidate control
channels for the wireless device. The candidate control channels
are a set of control channels that the wireless device is
configured to monitor.
[0070] DRX Awake Period: As used herein, the "DRX awake period" is
a period of time during which a wireless device operating according
to a DRX scheme is awake during a DRX cycle. In 3GPP LTE, the DRX
awake period includes one or more of the following: On Duration
Timer for long and short cycle, DRX Inactivity Timer, and DRX
Retransmission Timer.
[0071] Legacy Wireless Device: The term "legacy wireless device" as
used herein refers to a wireless device (e.g., an LTE UE) that
supports legacy DRX.
[0072] Enhanced Wireless Device: The term "enhanced wireless
device" or "enhanced UE" as used herein refers to a wireless device
(e.g., an LTE UE) that supports soft DRX.
[0073] Embodiments of the present disclosure that are presented
herein are generally applicable to any wireless network in which
the wireless device supports DRX.
[0074] Embodiments of the present disclosure are related to
achieving better tradeoffs between battery saving and latency to,
e.g., support ultra-low latency applications by introducing soft
DRX. Unlike legacy DRX where power consumption of a wireless device
(e.g., an LTE UE) alternates roughly between two discreet power
levels corresponding to Awake states and Sleep states, in soft DRX,
the power consumption levels of the wireless device can be a set of
more than two discreet power levels or ultimately resemble
continuous functions. By allowing more power consumption levels,
the wireless device can be Awake for longer times with the same
total energy consumption achieved by legacy DRX. To illustrate
this, FIGS. 2A and 2B show approximation of the power consumed by
monitoring control channel candidates for legacy DRX and an example
of soft DRX, respectively. The energy consumption due to monitoring
control channel candidates of each scheme during the Awake state
can be well approximated by the area of the square representing the
DRX awake period or Awake state of the legacy DRX and the area of
the triangle representing the DRX awake period or Awake state for
the soft DRX example. By examining the areas for both schemes, it
can be shown that both schemes consume the same amount of energy in
this example. However, the DRX awake period or duration of the
Awake state for the soft DRX example is twice that of the legacy
DRX example. As such, the maximum downlink latency for the soft DRX
is reduced as compared to that of the legacy DRX while at the same
time energy consumption is not increased (i.e., stays the same in
this example). Note that DRX Inactivity Timer, DRX Retransmission
Timer, and DRX short cycle are not shown FIGS. 2A and 2B.
[0075] In some embodiments, the energy consumption level is varied
in different time periods (e.g., subframes) within the DRX awake
period (i.e., within the Awake state) by varying the number of
candidate control channels that the wireless device monitors during
different time periods (e.g., subframes) within the DRX awake
period (i.e., during the Awake state). In some embodiments, the
energy consumption level is additionally or alternatively varied by
restricting the set of control channels to monitor to specific
Orthogonal Frequency Division Multiplexing (OFDM) symbols. For
instance, a triangle-like power shape such as that illustrated in
FIG. 2B can be approximated by gradually monitoring more candidate
control channels in every subframe during the DRX awake period
until the maximum power is reached, and then gradually monitoring
less candidate control channels in every subframe of the DRX awake
period until the wireless device goes to sleep. However, this is
only one example. Other non-limiting examples are described
below.
[0076] In some embodiments, a network node (e.g., a base station
such as an eNB) varies the soft DRX pattern (e.g., control channel
subsets to be monitored during different time periods (e.g.,
subframes) within the DRX Awake period) of a wireless device. In
addition, in some embodiments, a network node (e.g., a base station
such as an eNB) controls a wireless device to switch between legacy
DRX and soft DRX depending on, e.g., other events such as network
load, traffic type, and requests from the wireless device.
[0077] While not being limited to or by any particular advantage,
embodiments of the present disclosure provide a number of
advantages over legacy DRX. For example, soft DRX may be used to
reduce downlink latency introduced by legacy DRX without increasing
the energy consumption at the wireless device, which makes it
attractive for ultra-low latency applications that are expected to
be supported in next generation networks such as healthcare and
emergency notification systems.
[0078] A wireless network is considered herein where base stations
are used to serve wireless devices. Without loss of generality, the
description provided herein focuses on a single cell scenario where
a single base station is used to communicate with a single wireless
device; however, the present disclosure is not limited thereto. In
this regard, FIG. 3 illustrates one example of a wireless
communications network 10 in which embodiments of the present
disclosure may be implemented. As illustrated, the wireless
communications network 10 includes a Radio Access Network (RAN) 12
(e.g., an Evolved Universal Terrestrial RAN (EUTRAN)) including a
number of base stations 14 (e.g., LTE eNBs) serving corresponding
cells 16. Wireless devices 18 (e.g., LTE UEs) wirelessly transmit
and receive signals to and from the base stations 14, as will be
appreciated by one of ordinary skill in the art. The base stations
14 may more generally be referred to as radio access nodes. The
base stations 14 may be connected to one another via a
base-station-to-base-station interface (e.g., an X2 interface) and
connected to a core network 20 (e.g., an Evolved Packet Core (EPC))
via respective core network interfaces (e.g., S1 interfaces). The
core network 20 includes a number of core network nodes such as,
for example, MMEs, P-GWs, Serving Gateways (S-GWs), etc., as will
be appreciated by one of ordinary skill in the art.
[0079] The base station 14 is assumed to have configured the
wireless device(s) 18 that it serves with DRX. In LTE, such
configuration is performed by a Radio Resource Control (RRC)
message called a RRC reconfiguration message. This RRC message
includes a number of DRX parameters that the wireless device 18
needs to use for DRX such as DRX ON duration, long cycle length,
DRX Inactivity Timer, DRX Retransmission Timer, short cycle length,
short cycle timer, DRX Start offset, etc. The base station 14 and
the wireless device 18 will be synchronized in terms of DRX states,
i.e., the base station 14 knows precisely when the wireless device
18 is in the Awake state and when the wireless device 18 is in the
Sleep state. As mentioned before, a legacy wireless device is
required to monitor all control channel candidates that may be
assigned to it for every subframe when it is in the Awake state.
For instance, in LTE, legacy LTE UEs configured with Physical
Downlink Control Channel (PDCCH) are required to monitor 22 PDCCH
candidates in every subframe in the Awake state.
[0080] FIG. 4 illustrates the operation of a wireless device 18 and
a base station 14 according to some embodiments of the present
disclosure. Note that optional steps are indicated by dashed lines.
As illustrated, the base station 14 and the wireless device 18
communicate with one another to enable soft DRX (step 100). In
other words, the base station 14 and the wireless device 18
communicate to establish an agreement to use soft DRX. While this
can be done using any suitable procedure, soft DRX is enabled via
RRC signal in some example embodiments and enabled via Medium
Access Control (MAC) signaling in some other example
embodiments.
[0081] Assuming that soft DRX is enabled, during the DRX awake
period, the wireless device 18 monitors two or more control channel
subsets during two or more time periods (e.g., two or more
subframes) within the DRX awake period, respectively (step 102). In
other words, rather than monitoring all candidate control channels
for a transmission of Downlink Control Information (DCI) to the
wireless device 18 in all time periods (e.g., all subframes) within
the DRX awake period as is done by legacy wireless devices, the
wireless device 18 monitors different control channel subsets
during different time periods (e.g., different subframes) within
the DRX awake period. As used herein, a "control channel subset" is
a subset of a defined set of candidate control channels that may be
assigned to the wireless device 18. More precisely, as used herein,
a "control channel subset" is a subset of a defined set of
candidate control channels (CC_Candidate_Set) that may be assigned
to the wireless device 18, which can be denoted as
CC_SubsetCC_Candidate_Set, where CC_Subset is the control channel
subset and CC_Candidate_Set is the set of candidate control
channels. A first control channel subset is "different" than a
second control channel subset if any candidate control channel
included in the first control channel subset is not also included
in the second control channel subset or vice versa. As an example,
if the first control channel subset is {CC1, CC2, CC3} and the
second control channel subset is {CC1, CC2}, then the two control
channel subsets are different even though they have two candidate
control channels in common.
[0082] Thus, rather than monitoring all candidate control channels
for, e.g., a PDCCH transmission intended for the wireless device
18, the wireless device 18 monitors different control channel
subsets in different time periods (e.g., subframes) within the DRX
awake period. For example, in one time period (e.g., subframe), the
wireless device 18 may monitor all of the candidate control
channels; and, in another time period (e.g., another subframe), the
wireless device 18 may monitor less than all of the candidate
control channels, thereby reducing energy consumption.
[0083] Unlike legacy DRX where the wireless device's power
consumption alternates roughly between two discreet power levels
corresponding to Awake states and Sleep states, in soft DRX, the
wireless device's power consumption levels can be a set of more
than two discreet power levels or ultimately resemble continuous
functions. By allowing more power consumption levels, the wireless
device can be Awake for longer times with the same total energy
consumption achieved by legacy DRX, as illustrated in FIGS. 2A and
2B. As stated previously, the energy consumption for a certain
period of time during the Awake state can be measured by the area
under power curves during that period of time. In some embodiments,
soft DRX is configured to keep the area under the power curve less
than or equal to the area of legacy DRX, while extending the time
of the Awake state.
[0084] Varying the energy consumption levels in different subframes
in the Awake state is achieved by varying the number of control
channels that the wireless device 18 has to monitor. In particular,
the set of control channel candidates can be divided into subsets
(possibly overlapping subsets), where monitoring each subset leads
to a particular power consumption level. Thus, by designing the
subsets and assigning different subsets to different subframes in
the Awake state, the power consumption level of the wireless device
18 can be varied over the Awake state. The following are some
examples for designing control channel subsets that result in
reduced power consumption by the wireless device 18 in the Awake
state (i.e., the DRX awake period): [0085] Some subsets may include
less control channel candidates in a narrowband, which reduces the
power consumption. [0086] Some subsets may include control channel
candidates that are restricted in time, e.g., restricted to one
OFDM symbol period, so the wireless device 18 can sleep early in
the subframe. [0087] For wireless devices 18 that are configured
with Carrier Aggregation (CA), i.e., allowed to receive data in
more than one carrier, some subsets may include only the control
channels in a subset of the carriers that the wireless device 18
should monitor. For example, a wireless device 18 that is
configured with two carriers for downlink CA can have two control
channel subsets as follows: the first subset includes all control
channels in both carriers and the second subset includes the
control channels in only the primary carrier. By having some
subsets that include only the control channels in a subset of the
carriers that the wireless device 18 should monitor, the wireless
device 18 can turn off some of the circuitry that is used to
monitor the second carrier when it is required to monitor the
second subset, thereby reducing power consumption. In 5G, it is
envisioned that the wireless device 18 will be configured with a
large number of carriers in separate bands; thus, soft DRX may be
particularly advantageous in 5G wireless communications networks.
As another example, a wireless device 18 that is configured with
three carriers for downlink CA can have three control channel
subsets as follows: a first subset includes (e.g., all) control
channel candidates in the first carrier, the second subset includes
(e.g., all) control channel candidates of the second carrier, and a
third subset that includes (e.g., all) control channel candidates
of the third carrier. As another example, a wireless device 18 that
is configured with three carriers for downlink CA can have four
control channel subsets as follows: a first subset includes (e.g.,
all) control channel candidates of all three carriers, the second
subset includes (e.g., all) control channel candidates of the first
carrier, a third subset that includes (e.g., all) control channel
candidates of the second carrier, and a fourth subset that includes
(e.g., all) control channel candidates of the third carrier. [0088]
If a wireless device 18 is capable of receiving control information
in PDCCH and enhanced PDCCH (ePDCCH) types and the implementation
of the wireless device 18 requires different power consumptions for
PDCCH as compared to ePDCCH, then one can vary the power
consumption by varying the type of control channels in the subsets.
For instance, one subset may include some or all of the PDCCH
channel candidates (but, e.g., none of the ePDCCH control channel
candidates), and another subset may include some or all ePDCCH
control channel candidates (but, e.g., none of the PDCCH control
channel candidates). [0089] Some control channels may be designed
to have a less sophisticated modulation and encoding scheme (i.e.,
a low complexity modulation and coding scheme) so it requires less
power to decode them. Such control channels may carry less control
information. For instance, such control channels may carry a very
small amount of control information that is sufficient to allow the
wireless device 18 to activate its DRX Inactivity Timer or to move
to legacy DRX. A "low complexity" modulation and coding scheme is a
modulation and coding scheme that requires less power consumption
at the wireless device 18 to perform the demodulation and decoding
since it requires less computational steps. For instance, one bit
may be sent with repetition coding, which is much easier to decode
than several bits encoded with convolutional coding.
[0090] Similarly, during the DRX awake period (i.e., the Awake
state) of the wireless device 18, the base station 14 transmits DCI
to the wireless device 18 in a time period (e.g., subframe) within
the DRX awake period of the wireless device 18 on one or more
control channels (e.g., one or more PDCCHs) from one of the two or
more control channel subsets that is monitored by the wireless
device 18 during that time period (step 104). In other words, for a
particular time period within the DRX awake period, the wireless
device 18 monitors a respective control channel subset. Thus,
assuming that the wireless device 18 is to be scheduled during that
time period, the base station 14 transmits DCI to the wireless
device 18 using one or more of the control channels in the control
channel subset being monitored by the wireless device 18 during
that time period.
[0091] Optionally, the wireless device 18 processes any received
DCI, as will be appreciated by one of ordinary skill in the art
(step 106). For example, if the DCI indicates downlink resources
scheduled for a downlink data transmission to the wireless device
18 in the time period, then the wireless device 18 receives that
downlink data transmission in accordance with the DCI.
[0092] When enabling, or activating, soft DRX in step 100 of FIG.
4, one or more soft DRX parameters may be configured for the
wireless device 18. In some embodiments, in addition to the legacy
DRX parameters, the soft DRX parameters may include one or more of
the following: [0093] One or more parameters that indicate the
types of Awake periods which soft DRX should be used. For instance,
one or more soft DRX parameters may specify whether soft DRX should
be used for one or more of the following types of Awake periods:
long cycle On Duration Timer, short cycle On Duration Timer, DRX
Inactivity Timer, and/or DRX Retransmission Timer. The rest of the
parameters below can be applied to all types of Awake periods or
they can be specified for each type of Awake period separately. For
instance, it may be desired to apply soft DRX only in long cycle On
Duration Timer, and use legacy DRX for short cycle On Duration
Timer, DRX Inactivity Timer, and DRX Retransmission Timer; in this
case, the parameters below will be used only for long cycle On
Duration Timer. [0094] A soft DRX parameter that indicates the
number of control channel candidate subsets [0095] The number of
control channel candidate subsets can be any integer greater than
or equal to 1. However, for simplicity, it may be beneficial to
restrict the set of possible numbers of control channel candidate
subsets; e.g., this set can be {1, 2, 4, 6} and, in this case, two
bits are sufficient to indicate the number of control channel
candidate subsets. [0096] One or more soft DRX parameters that, for
each control channel subset, indicate: [0097] The control channel
candidates that belong to the control channel subset. [0098] A
control channel subset can include any set of the candidate control
channels. However, for simplicity, it may be beneficial to restrict
the set of possible control channel candidates for each subset in
order to reduce the number of bits needed to indicate which control
channel candidates belongs to each subset. For example, the control
channel candidates can be one of the following four possibilities
which requires two bits per subset: fall control channel
candidates, first half of control channel candidates, second half
of control channel candidates, control channel candidates with even
indices}. [0099] The subframes where this control channel subset
should be used. [0100] A control channel subset can be indicated to
be used for any set of one or more subframes. However, for
simplicity, it may be beneficial to restrict the set of possible
subframes for each control channel subset in order to reduce the
number of bits needed to indicate which subframe(s) belongs to each
control channel subset. For example, the subframes can be one of
the following four possibilities which require two bits per subset:
{first half of subframes in the awake period, second half of
subframes in the awake period, first 70% of subframes in the awake
period, last 30% of subframes in the awake period}.
[0101] An alternative way to simplify the exchange of soft DRX
parameters is to define soft DRX profiles which are known a priori
to both the base station 14 and the wireless device 18, e.g.,
stored in a lookup table, where each profile includes different
soft DRX parameters. This way, only the index of the soft DRX
profile can be exchanged to configure soft DRX.
[0102] FIGS. 5 through 7 illustrate example embodiments of step 100
of FIG. 4. In particular, FIG. 5 illustrates one example in which
soft DRX is enabled, or activated, via, e.g., RRC signaling
according to some embodiments of the present disclosure. As
illustrated, the wireless device 18 sends capability information to
the base station 14 (step 200). This capability information
includes an indication as to whether the wireless device 18
supports soft DRX. In some embodiments, the wireless device 18
sends its capability information to the base station 14 during RRC
connection establishment. For existing LTE UEs, capability
information may be modified to include an indication of whether the
LTE UE supports soft DRX.
[0103] The base station 14 decides whether to activate soft DRX
based on the capability information of the wireless device 18 (step
202). In particular, if both the wireless device 18 and the base
station 14 support soft DRX, then the base station 14 decides to
activate soft DRX. Otherwise, the base station 14 decides not to
activate soft DRX. Assuming that the base station 14 decides to
activate soft DRX, the base station 14 sends one or more soft DRX
parameters to the wireless device 18, e.g., in an RRC message (step
204). In some embodiments, the base station 14 sends an RRC
reconfiguration message to the wireless device 18, where the RRC
reconfiguration message indicates to the wireless device 18 that
soft DRX is to be activated with one or more soft DRX parameters
specified in the RRC reconfiguration message. The one or more soft
DRX parameters may include, for example, an indication of the two
or more control channel subsets to be monitored by the wireless
device 18 and the two or more respective time periods in which the
two or more control channel subsets are to be monitored. For
example, for each subframe in the DRX awake period, the one or more
soft DRX parameters may include an indication of the control
channel subset to be monitored by the wireless device 18 in that
subframe.
[0104] Optionally, at some point after activating soft DRX, the
base station 14 may decide to deactivate soft DRX (step 206). This
decision may be made based on any suitable criteria such as, for
example, the occurrence of particular one or more events, such as
change in traffic, number of connected wireless devices, wireless
device's battery status, etc. The base station 14 then sends a
message to the wireless device 18 instructing the wireless device
18 to deactivate soft DRX (step 208). This message may again be
sent via RRC signaling (e.g., an RRC reconfiguration message).
[0105] FIG. 6 illustrates one example in which soft DRX is enabled,
or activated, via, e.g., MAC signaling according to some
embodiments of the present disclosure. As illustrated, the wireless
device 18 sends a message to the base station 14 requesting
activation of soft DRX (step 300). In some embodiments, this
message is provided via a MAC Control Element (CE) that includes
one or more desired soft DRX parameters or one or more desired
modifications to pre-existing soft DRX parameters. Again, the one
or more soft DRX parameters may include, for example, an indication
of the two or more control channel subsets to be monitored by the
wireless device 18 and the two or more respective time periods in
which the two or more control channel subsets are to be
monitored.
[0106] The base station 14 decides whether to accept soft DRX
activation (step 302). This decision may be based on any suitable
criteria such as, for example, the capability of the base station
14 to support soft DRX, number of connected wireless devices, and
traffic conditions, etc. The base station 14 sends a message either
accepting or rejecting soft DRX activation as decided in step 302
(step 304). In some embodiments, the message accepting or rejecting
soft DRX activation may be sent via a MAC CE. While not
illustrated, the wireless device 18 (and the base station 14) will
use soft DRX if activation of soft DRX is accepted or not use soft
DRX if activation of soft DRX is rejected.
[0107] Optionally, the base station 14 and/or the wireless device
18 may subsequently decide to deactivate soft DRX, in which case
appropriate communication is performed to deactivate soft DRX. For
example, at some point after activating soft DRX, the base station
14 may decide to deactivate soft DRX (step 306). This decision may
be made based on any suitable criteria such as, for example, the
occurrence of particular one or more events, such as change in
traffic, number of connected wireless devices, wireless device's
battery status, etc. The base station 14 then sends a message to
the wireless device 18 instructing the wireless device 18 to
deactivate soft DRX (step 308). This message may again be sent via
a MAC CE. Alternatively, at some point after activating soft DRX,
the wireless device 18 may decide to deactivate soft DRX (step
310). This decision may be made based on any suitable criteria such
as, for example, the occurrence of particular one or more events,
such as change in traffic, number of connected wireless devices,
wireless device's battery status, etc. The wireless device 18 then
sends a message to the base station 14 requesting deactivation of
soft DRX (step 312). This message may again be sent via a MAC CE.
Further, the request for deactivation may, in some embodiments, be
either accepted or rejected by the base station 14.
[0108] FIG. 7 illustrates another example in which soft DRX is
enabled, or activated, via, e.g., MAC signaling according to some
embodiments of the present disclosure. As illustrated, the base
station 14 sends a message to the wireless device 18 requesting
activation of soft DRX (step 400). In some embodiments, this
message is provided via a MAC CE that includes one or more desired
soft DRX parameters or one or more desired modifications to
pre-existing soft DRX parameters. Again, the one or more soft DRX
parameters may include, for example, an indication of the two or
more control channel subsets to be monitored by the wireless device
18 and the two or more respective time periods in which the two or
more control channel subsets are to be monitored.
[0109] The wireless device 18 decides whether to accept soft DRX
activation (step 402). This decision may be based on any suitable
criteria such as, for example, the capability of the wireless
device 18 to support soft DRX, number of connected wireless
devices, and traffic conditions, etc. The wireless device 18 sends
a message either accepting or rejecting soft DRX activation as
decided in step 402 (step 404). In some embodiments, the message
accepting or rejecting soft DRX activation may be sent via a MAC
CE. While not illustrated, the base station 14 (and the wireless
device 18) will use soft DRX if activation of soft DRX is accepted
or not use soft DRX if activation of soft DRX is rejected.
[0110] Optionally, the base station 14 and/or the wireless device
18 may subsequently decide to deactivate soft DRX, in which case
appropriate communication is performed to deactivate soft DRX. For
example, at some point after activating soft DRX, the base station
14 may decide to deactivate soft DRX (step 406). This decision may
be made based on any suitable criteria such as, for example, the
occurrence of particular one or more events, such as change in
traffic, number of connected wireless devices, wireless device's
battery status, etc. The base station 14 then sends a message to
the wireless device 18 instructing the wireless device 18 to
deactivate soft DRX (step 408). This message may again be sent via
a MAC CE. Alternatively, at some point after activating soft DRX,
the wireless device 18 may decide to deactivate soft DRX (step
410). This decision may be made based on any suitable criteria such
as, for example, the occurrence of particular one or more events,
such as change in traffic, number of connected wireless devices,
wireless device's battery status, etc. The wireless device 18 then
sends a message to the base station 14 requesting deactivation of
soft DRX (step 412). This message may again be sent via a MAC CE.
Further, the request for deactivation may, in some embodiments, be
either accepted or rejected by the base station 14.
[0111] FIG. 8 is a flow chart that illustrates step 104 of FIG. 4
in more detail according to some embodiments of the present
disclosure. Note that while the process is described as including a
number of "steps," the "steps" may be performed in any order or
some of the steps may be performed in parallel unless otherwise
indicated or required. As illustrated, the base station 14
initializes a subframe index i to, in this example, 1 (step 500).
When the subframe index i is 1, the subframe index i refers to the
first subframe in the DRX awake period of the wireless device 18.
Likewise, a subframe index i equal to 2 refers to the second
subframe in the DRX awake period of the wireless device 18.
[0112] The base station 14 determines a control channel subset to
be monitored by the wireless device 18 during the i-th subframe of
the DRX awake period of the wireless device 18 based on the soft
DRX parameters configured for the wireless device 18 (i.e., based
on the soft DRX configuration of the wireless device 18) (step
502). In some embodiments, the control channel subset for the i-th
subframe of the DRX awake period may be determined based on the
soft DRX parameters configured for the wireless device 18, subframe
number, and optionally a wireless device (e.g., UE) identifier
(e.g., RNTI). The base station 14 also determines whether the
wireless device 18 is to be scheduled for the i-th subframe of the
DRX awake period of the wireless device 18 (step 504). If not, the
process proceeds to step 508. However, if the wireless device 18 is
to be scheduled in the i-th subframe of the DRX awake period, the
base station 14 transmits DCI in one or more control channels that
are in the control channel subset to be monitored by the wireless
device 18 for the i-th subframe (step 506). In this manner, the
base station 14 limits the control channel(s) on which the DCI is
transmitted to the wireless device 18 to those being monitored by
the wireless device 18 in the i-th subframe.
[0113] Whether proceeding from the NO decision in step 504 or from
step 506, the base station 14 determines whether the i-th subframe
is the last subframe in the DRX awake period of the wireless device
18 (step 508). If so, the process ends. Otherwise, the base station
14 increments the subframe index i (step 510), and the process
returns to step 502 and is repeated for the next subframe. Using
the process of FIG. 8, the base station 14 operates to, in each
subframe in which the wireless device 18 is awake, determine the
control channel subset to be monitored by the wireless device 18 in
that subframe and, if appropriate, transmit DCI to the wireless
device 18 in that subframe on one or more of the control channels
in the control channel subset being monitored by the wireless
device 18.
[0114] FIG. 9 is a flow chart that illustrates step 102 of FIG. 4
in more detail according to some embodiments of the present
disclosure. Note that while the process is described as including a
number of "steps," the "steps" may be performed in any order or
some of the steps may be performed in parallel unless otherwise
indicated or required. As illustrated, the wireless device 18
initializes a subframe index i to, in this example, 1 (step 600).
When the subframe index i is 1, the subframe index i refers to the
first subframe in the DRX awake period of the wireless device 18.
Likewise, a subframe index i equal to 2 refers to the second
subframe in the DRX awake period of the wireless device 18.
[0115] The wireless device 18 determines a control channel subset
to be monitored by the wireless device 18 during the i-th subframe
of the DRX awake period of the wireless device 18 based on the soft
DRX parameters configured for the wireless device 18 (i.e., based
on the soft DRX configuration of the wireless device 18), subframe
number, and optionally based on a wireless device (e.g., UE)
identifier such as an RNTI (step 602). In some embodiments, the
control channel subset to be monitored by the wireless device 18
during the i-th subframe of the DRX awake period may be determined
based on the soft DRX parameters configured for the wireless device
18, subframe number, and optionally a wireless device (e.g., UE)
identifier (e.g., RNTI). The wireless device 18 then monitors the
candidate control channels in the determined control channel subset
for the i-th subframe of the DRX awake period (step 604). In some
embodiments, this monitoring is or at least includes blind decoding
over all of the candidate control channels in the control channel
subset determined for the i-th subframe. In this manner, rather
than monitoring all possible candidate control channels in all
subframes, the wireless device 18 monitors only those candidate
control channels in the control channel subset configured for the
particular subframe.
[0116] The wireless device 18 determines whether the i-th subframe
is the last subframe in the DRX awake period of the wireless device
18 (step 606). If so, the process ends. Otherwise, the wireless
device 18 increments the subframe index i (step 608), and the
process returns to step 602 and is repeated for the next subframe.
Using the process of FIG. 9, the wireless device 18 operates to, in
each subframe in which the wireless device 18 is awake, determine
the control channel subset to be monitored by the wireless device
18 in that subframe and monitor only those candidate control
channels in the determined control channel subset.
[0117] A simple and practical embodiment of soft DRX can be
constructed by dividing the set of candidate control channels that
the wireless device 18 is supposed to monitor into two control
channel subsets. Each of these two control channel subsets is
assigned to a respective subset of the subframes in the DRX awake
period of the wireless device 18. One specific example of this
embodiment is described below with respect to FIG. 10 and FIGS. 11A
and 11B. To facilitate the discussion, followings symbols are
defined:
TABLE-US-00002 Symbol Definition P.sub.1 the power required by the
wireless device to monitor the first control channel subset using
soft DRX P.sub.2 the power required by the wireless device to
monitor the second control channel subset using soft DRX
P.sub.legacy the power required by the wireless device to monitor
all control channel candidates using legacy DRX n.sub.1 Number of
subframes where the wireless device is Awake and it is expected to
monitor the first control channel subset using soft DRX n.sub.2
Number of subframes where the wireless device is Awake and it is
expected to monitor the second control channel subset using soft
DRX n.sub.legacy Number of subframes where the wireless device is
Awake and it is expected to monitor all control channel candidates
using legacy DRX
[0118] One can design soft DRX to insure that it results in the
same or less energy while making the wireless device 18 stay awake
for longer or similar duration as compared to legacy DRX by
satisfying the following equations:
n.sub.1P.sub.1+n.sub.2P.sub.2.ltoreq.n.sub.legacyP.sub.legacy,
(Energy constraint)
n.sub.1+n.sub.2.gtoreq.n.sub.legacy. (Awake period constraint)
[0119] Example 1: Assume the first and second control channel
subsets are chosen such that the first control channel subset is
the same as legacy DRX while the second control channel subset
requires only 50% of the power to be monitored, i.e.,
P.sub.1=P.sub.legacy and P.sub.2=0.5 P.sub.legacy. The first
control channel subset provides the base station 14 the same
flexibility in scheduling the wireless device 18 as compared to
legacy DRX, as the wireless device 18 is expected to decode all
control channel candidates. However, the second control channel
subset provides the base station 14 with less flexibility as the
wireless device 18 is expected to monitor fewer candidate control
channels. Further, assume the Awake period of the legacy DRX is ten
subframes.
In FIG. 10, all feasible values of n.sub.1 and n.sub.2 that satisfy
the two constraints above are plotted. The constraint lines are
also shown in FIG. 10. Higher values of n.sub.2 result in more
battery saving and less latency, but lower scheduling flexibility.
On the other hand, higher values of n.sub.1 result in less battery
saving and more latency, but higher scheduling flexibility. Hence,
in choosing n.sub.1 and n.sub.2, it is important to have good
tradeoff between battery saving, latency, and scheduling
flexibility.
[0120] One example solution is to have n.sub.1=5 and n.sub.2=10,
which results in the same energy consumption of legacy DRX but with
a total awake period of 15 subframes, i.e., 50% more than legacy
DRX. The gain comes at the expense that the base station 14 will
have the same flexibility of scheduling the wireless device 18 as
compared to legacy DRX for only five subframes instead of ten
subframes. An illustration of the soft DRX profile compared to the
legacy DRX profile for n.sub.1=5 and n.sub.2=10 is shown in FIGS.
11A and 11B.
[0121] The embodiment described above for two control channel
subsets can be generalized by dividing the set of candidate control
channels that the wireless device 18 is supposed to monitor into K
subsets, and assigning each control channel subset to a respective
subset of the subframes in the DRX awake period of the wireless
device 18. To facilitate the discussion, the following symbols are
defined:
TABLE-US-00003 Symbol Definition P.sub.k the power required by the
wireless device to monitor the k.sup.th control channel subset
using soft DRX n.sub.k Number of subframes where the wireless
device is Awake and it is expected to monitor the k.sup.th control
channel subset using soft DRX
[0122] One can design soft DRX to ensure that it results in the
same or less energy while making the wireless device 18 stay awake
for longer or similar duration compared to legacy DRX by satisfying
the following equations:
.SIGMA..sub.k=1.sup.Kn.sub.kP.sub.k.ltoreq.n.sub.legacyP.sub.legacy,
(Energy constraint)
.SIGMA..sub.k=1.sup.Kn.sub.k.gtoreq.n.sub.legacy. (Awake period
constraint)
[0123] As noted above, by reducing the number of control channel
candidates monitored by the wireless device 18 in a particular
subframe, the base station 14 will have less flexibility in
scheduling the wireless device 18 in that subframe. For instance,
if two wireless devices 18 monitor only the same, single candidate,
then these two wireless devices 18 cannot be scheduled at the same
time in a subframe. Thus, it is expected that using soft DRX may
lead to reduced scheduling flexibility at the base station 14
compared to legacy DRX, as soft DRX limits the number of control
channels monitored by the wireless device 18 in some subframes.
[0124] In some embodiments, one or more techniques are applied to
improve the scheduling flexibility of the base station 14 when soft
DRX is used. In particular, in some embodiments, different wireless
devices 18 or different groups of wireless devices 18 may be
configured with different DRX offsets such that a subframe(s) to
which a control channel subset having a limited number of candidate
control channels is assigned for one wireless device 18 (or one
group of wireless devices 18) does not overlap with a subframe(s)
to which the same control channel subset is assigned to another
wireless device 18 (or another group of wireless devices 18). In
this manner, scheduling flexibility is improved.
[0125] More specifically, the limit in scheduling flexibility is
mainly observed in the event when there is more than one wireless
device 18 that monitor limited and similar control channel subsets
at the same time. To reduce the probability of such an event, the
base station 14 can properly assign different DRX offsets
(drxStartOffset) for different wireless devices 18, where
drxStartOffset is defined as the starting time with respect to
subframe number when the wireless device 18 activates the On
Duration Timer. To illustrate this, FIGS. 12A and 12B show the soft
DRX profiles of two wireless devices 18, assuming that both
wireless devices 18 use the soft DRX profile provided in Example 1
and shown in FIG. 11B. It can be seen from FIGS. 12A and 12B that
the second control subset of the two wireless devices 18 do not
overlap by properly adjusting the drxStartOffset. In this manner,
scheduling flexibility is improved.
[0126] In some embodiments, another technique that may be used to
improve scheduling flexibility when using soft DRX is as follows.
Whenever there is initial uplink or downlink transmission, the
Awake state is extended by starting or re-starting a DRX Inactivity
Timer. The rationale behind starting the DRX Inactivity Timer is
that the wireless device 18 is likely to have more uplink/downlink
data. During the DRX Inactivity Timer, it is advantageous from a
scheduling flexibility point of view to monitor all control channel
candidates (i.e., similar to legacy DRX) for most (if not all) of
the DRX Inactivity Timer as it is likely that the wireless device
18 will have more uplink/downlink data. Thus, in some embodiments,
even when soft DRX is active, the wireless device 18 monitors all
candidate control channels during the DRX Inactivity Timer. This
enables the base station 14 to transmit DCI to the wireless device
18 on any of the candidate control channels during the DRX
Inactivity Timer.
[0127] In some embodiments, another technique that may be used to
improve scheduling flexibility when using soft DRX is as follows.
Since the set of all control channel candidates can be determined
by a wireless device's identifier (e.g., using an RNTI in LTE), the
base station 14 can properly assign different wireless device
identifiers for those wireless devices 18 with soft DRX such that
the overlap is minimized for all control channel candidates or at
least for the control channel subset having a limited number of
candidate control channels.
[0128] Modifying the DRX parameters for legacy DRX is supported in
the LTE standard. This can be done by sending an RRC
Reconfiguration message with a new DRX configuration. Modifying the
DRX parameters for legacy DRX using MAC CEs is also possible. As
discussed above, in some embodiments, switching between legacy DRX
and soft DRX, e.g., due to particular events, may be performed
using, e.g., either RRC signaling or MAC CEs. For instance, if the
base station 14 is overloaded with many wireless devices 18, the
base station 14 may request some or all of the wireless devices 18
to switch to legacy DRX in order to have full scheduling
flexibility. In another instance, the base station 14 may request
the wireless device 18 to change its soft DRX parameters, such as
the number of control channel subsets. Similarly, the wireless
device 18 may request a change to its soft DRX parameters due to
any event, such as running low on battery power.
[0129] FIG. 13 is a schematic block diagram of the wireless device
18 according to some embodiments of the present disclosure. As
illustrated, the wireless device 18 includes one or more processors
22 (e.g., Central Processing Units (CPUs), Application Specific
Integrated Circuits (ASICs), Field Programmable Gate Arrays
(FPGAs), and/or the like), memory 24, and one or more transceivers
26 each including one or more transmitters 28 and one or more
receivers 30 coupled to one or more antennas 32. In some
embodiments, the functionality of the wireless device 18 described
herein may be fully or partially implemented in software that is,
e.g., stored in the memory 24 and executed by the processor(s)
22.
[0130] In some embodiments, a computer program including
instructions which, when executed by at least one processor, causes
the at least one processor to carry out the functionality of the
wireless device 18 according to any of the embodiments described
herein is provided. In some embodiments, a carrier comprising the
aforementioned computer program product is provided. The carrier is
one of an electronic signal, an optical signal, a radio signal, or
a computer readable storage medium (e.g., a non-transitory computer
readable medium such as memory).
[0131] FIG. 14 is a schematic block diagram of the wireless device
18 according to some other embodiments of the present disclosure.
The wireless device 18 includes one or more modules 34, each of
which is implemented in hardware, software, or combinations of
both. As an example, in some embodiments, the one or more modules
34 include one or more modules that operate to perform the
functionality of the wireless device 18 with respect to the process
described above. For example, the modules 34 may include a
monitoring module 34-1 that operates to monitor, during a DRX awake
period, two or more control channel subsets during two or more time
periods within the DRX awake period, respectively, wherein the two
or more control channel subsets are different subsets of a
plurality of candidate control channels, as described above. The
modules 34 may include additional modules that perform the
additional functionality of the wireless device 18 described
above.
[0132] FIG. 15 is a schematic block diagram of a network node 36
according to some embodiments of the present disclosure. The
network node 36 may be, for example, a radio access node such as,
for example, a base station 14 or a core network node such as, for
example, a node in the core network 20 of FIG. 3. As illustrated,
the network node 36 includes a control system 38 that includes one
or more processors 40 (e.g., CPUs, ASICs, FPGAs, and/or the like),
memory 42, and a network interface 44. In addition, if the network
node 36 is a radio access node, then the network node 36 also
includes one or more radio units 46 that each includes one or more
transmitters 48 and one or more receivers 50 coupled to one or more
antennas 52. In some embodiments, the radio unit(s) 46 is external
to the control system 38 and connected to the control system 38
via, e.g., a wired connection (e.g., an optical cable). However, in
some other embodiments, the radio unit(s) 46 and potentially the
antenna(s) 52 are integrated together with the control system 38.
The one or more processors 40 operate to provide one or more
functions of a network node as described herein. In some
embodiments, the function(s) are implemented in software that is
stored, e.g., in the memory 42 and executed by the one or more
processors 40.
[0133] FIG. 16 is a schematic block diagram that illustrates a
virtualized embodiment of the network node 36 according to some
embodiments of the present disclosure. As used herein, a
"virtualized" network node (e.g., a virtualized base station or a
virtualized radio access node) is an implementation of the network
node in which at least a portion of the functionality of the
network is implemented as a virtual component (e.g., via a virtual
machine(s) executing on a physical processing node(s) in a
network(s)). As illustrated, in this example, the network node 36
may include the control system 38 that includes the one or more
processors 40 (e.g., CPUs, ASICs, FPGAs, and/or the like), the
memory 42, and the network interface 44 and, depending on the type
of network node, the one or more radio units 46 that each includes
the one or more transmitters 48 and the one or more receivers 50
coupled to the one or more antennas 52, as described above. The
control system 38 is connected to the radio unit(s) 46 via, for
example, an optical cable or the like. The control system 38 is
connected to one or more processing nodes 54 coupled to or included
as part of a network(s) 56 via the network interface 44. Each
processing node 54 includes one or more processors 58 (e.g., CPUs,
ASICs, FPGAs, and/or the like), memory 60, and a network interface
62.
[0134] In this example, functions 64 of the network node 36 (e.g.,
functions of the base station 14) described herein are implemented
at the one or more processing nodes 54 or distributed across the
control system 38 and the one or more processing nodes 54 in any
desired manner. In some particular embodiments, some or all of the
functions 64 of the network node 36 described herein are
implemented as virtual components executed by one or more virtual
machines implemented in a virtual environment(s) hosted by the
processing node(s) 54. As will be appreciated by one of ordinary
skill in the art, additional signaling or communication between the
processing node(s) 54 and the control system 38 is used in order to
carry out at least some of the desired functions 64. Notably, in
some embodiments, the control system 38 may not be included, in
which case the radio unit(s) 46 communicate directly with the
processing node(s) 54 via an appropriate network interface(s).
Further, in embodiments in which the network node 36 is not a radio
access node (e.g., a core network node), then the network node 36
may be entirely virtualized (i.e., there may be no control system
38 or radio unit(s) 46.
[0135] In some embodiments, a computer program including
instructions which, when executed by at least one processor, causes
the at least one processor to carry out the functionality of a
network node or a node (e.g., a processing node 54) implementing
one or more of the functions 64 of the network node in a virtual
environment according to any of the embodiments described herein is
provided. In some embodiments, a carrier comprising the
aforementioned computer program product is provided. The carrier is
one of an electronic signal, an optical signal, a radio signal, or
a computer readable storage medium (e.g., a non-transitory computer
readable medium such as memory).
[0136] FIG. 17 is a schematic block diagram of the network node 36
according to some other embodiments of the present disclosure. The
network node 36 includes one or more modules 66, each of which is
implemented in hardware, software, or combinations of both. The
module(s) 66 provide the functionality of the network node 36
described herein. For example, the module(s) 66 may include one or
modules that perform the operations of the base station 14
described above. In particular, the module(s) 66 may include a
transmission module 66-1 operable to initiate transmission, during
a DRX awake period of a wireless device 18, of DCI to the wireless
device 18 in a time period within the DRX awake period of the
wireless device 18 on one or more control channels in one of at
least two control channel subsets, wherein the at least two control
channel subsets are at least two different subsets of a plurality
of candidate control channels that are configured for the wireless
device 18 for at least two time periods within the DRX awake period
of the wireless device (18), respectively.
[0137] The following acronyms are used throughout this disclosure.
[0138] .mu.s Microsecond [0139] 3GPP Third Generation Partnership
Project [0140] 5G Fifth Generation [0141] ASIC Application Specific
Integrated Circuit [0142] CA Carrier Aggregation [0143] CE Control
Element [0144] CPU Central Processing Unit [0145] DCI Downlink
Control Information [0146] DRX Discontinuous Reception [0147] eNB
Enhanced or Evolved Node B [0148] EPC Evolved Packet Core [0149]
ePDCCH Enhanced Physical Downlink Control Channel [0150] EUTRAN
Evolved Universal Terrestrial Radio Access Network [0151] FPGA
Field Programmable Gate Array [0152] kHz Kilohertz [0153] LTE Long
Term Evolution [0154] MAC Medium Access Control [0155] MME Mobility
Management Entity [0156] ms Millisecond [0157] MTC Machine Type
Communication [0158] OFDM Orthogonal Frequency Division
Multiplexing [0159] PDCCH Physical Downlink Control Channel [0160]
PDN Packet Data Network [0161] PDSCH Physical Downlink Shared
Channel [0162] P-GW Packet Data Network Gateway [0163] PRB Physical
Resource Block [0164] RAN Radio Access Network [0165] RE Resource
Element [0166] RNTI Radio Network Temporary Identifier [0167] RRC
Radio Resource Control [0168] SCEF Service Capability Exposure
Function [0169] S-GW Serving Gateway [0170] TR Technical Report
[0171] TS Technical Specification [0172] UE User Equipment
[0173] Those skilled in the art will recognize improvements and
modifications to the embodiments of the present disclosure. All
such improvements and modifications are considered within the scope
of the concepts disclosed herein and the claims that follow.
* * * * *