U.S. patent application number 15/496706 was filed with the patent office on 2017-10-26 for user equipment and method in a communications network.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Jessica Ostergaard, Mikael Wittberg.
Application Number | 20170311373 15/496706 |
Document ID | / |
Family ID | 46168599 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170311373 |
Kind Code |
A1 |
Ostergaard; Jessica ; et
al. |
October 26, 2017 |
User Equipment and Method in a Communications Network
Abstract
A method in a user equipment for deciding whether to send an
uplink transmission to a radio access network node is provided. The
user equipment and radio access network node are comprised in a
communications network. The user equipment is configured with
Discontinuous Reception (DRX), wherein the user equipment is in
active time or not in active time. The user equipment decides
whether to send the uplink transmission at a transmission time t,
based on the DRX status of the user equipment at a predefined
earlier time instance relative to the transmission time t.
Inventors: |
Ostergaard; Jessica;
(Stockholm, SE) ; Wittberg; Mikael; (Uppsala,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
46168599 |
Appl. No.: |
15/496706 |
Filed: |
April 25, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14238393 |
Feb 11, 2014 |
9668207 |
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PCT/SE2012/050490 |
May 9, 2012 |
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15496706 |
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61522981 |
Aug 12, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 76/28 20180201;
Y02D 70/25 20180101; Y02D 70/142 20180101; Y02D 70/1262 20180101;
H04W 76/20 20180201; H04W 52/0274 20130101; Y02D 70/146 20180101;
Y02D 70/1242 20180101; H04W 52/0209 20130101; Y02D 30/70 20200801;
Y02D 70/21 20180101; Y02D 70/24 20180101 |
International
Class: |
H04W 76/04 20090101
H04W076/04; H04W 52/02 20090101 H04W052/02 |
Claims
1. A method in a user equipment configured to operate with
Discontinuous Reception (DRX) in a radio access network, wherein a
corresponding DRX status of the user equipment is either active or
inactive, the method comprising: deciding whether to send an uplink
transmission for a radio access network node at a transmission time
t, based on the DRX status of the user equipment at a predefined
earlier time instance relative to the transmission time t.
2. The method of claim 1, wherein the uplink transmission comprises
at least one of periodic uplink control signaling and transmission
of a sounding reference signal.
3. The method of claim 2, wherein the periodic uplink control
signaling comprises Channel State Information (CSI) comprising all
of or any subsets of Channel Quality Indication (CQI), Precoding
Matrix Indicator (PMI), Rank Indication (RI), and Precoder Type
Indicator (PTI).
4. The method of claim 2, further comprising: deciding a format to
use for sending other uplink control signaling together with the
periodic uplink control signaling, based on the DRX status of the
user equipment at the predefined earlier time instance relative to
the transmission time t.
5. The method of claim 4, wherein the other uplink control
signaling comprises at least one of Hybrid Automatic Repeat ReQuest
(HARQ) feedback and Acknowledgement/Not acknowledgement (A/N)
feedback.
6. The method of claim 1, wherein the uplink transmission comprises
a sounding reference signal transmission and wherein the method
further comprises deciding whether to puncture an uplink data
transmission coinciding with the transmission time t with the
sounding reference signal transmission, based on the DRX status of
the user equipment at the predefined earlier time instance relative
to the transmission time t.
7. The method of claim 6, wherein the uplink data transmission is
to be sent on a Physical Uplink Shared Channel (PUSCH).
8. The method of claim 6, wherein, when the decision is made to
puncture the uplink data transmission with the sounding reference
signal transmission, the method includes puncturing a last symbol
of the uplink data.
9. The method of claim 1, wherein the method further comprises
deciding whether to send the uplink transmission in further
dependence on whether another uplink transmission from the user
equipment coincides with the transmission time t.
10. The method of claim 1, further comprising deciding to base the
transmission decision at the transmission time t on the DRX status
of the user equipment at the predefined earlier time instance in
dependence on there having been a change in an active time of the
user equipment for DRX operation, due to radio access network node
signaling or radio access network node data transmission to the
user equipment.
11. A user equipment configured for operation in a radio access
network and comprising: radio circuitry configured for
communicating with the radio access network; and a processing
circuit operatively associated with the radio circuitry and
configured to: operate the user equipment in a Discontinuous
Reception (DRX) configuration, wherein a corresponding DRX status
of the user equipment is either active or inactive; and decide
whether to send an uplink transmission for a radio access network
node at a transmission time t, based on the DRX status of the user
equipment at a predefined earlier time instance relative to the
transmission time t.
12. The user equipment of claim 11, wherein the uplink transmission
comprises at least one of a periodic uplink control signaling and
transmission of a sounding reference signal.
13. The user equipment of claim 12, wherein the periodic uplink
control signaling comprises Channel State Information (CSI),
comprising all of or any subsets of Channel Quality Indication
(CQI), Precoding Matrix Indicator (PMI), Rank Indication (RI), and
Precoder Type Indicator (PTI).
14. The user equipment of claim 12, wherein the processing circuit
is configured to decide a format to use for sending other uplink
control signaling together with the periodic uplink control
signaling, based on the DRX status of the user equipment at the
predefined earlier time instance relative to the transmission time
t.
15. The user equipment of claim 14, wherein the other uplink
control signaling comprises at least one of Hybrid Automatic Repeat
ReQuest (HARQ) feedback and Acknowledgement/Not acknowledgement
(A/N) feedback.
16. The user equipment of claim 11 wherein the uplink transmission
comprises a sounding reference signal transmission and wherein the
processing circuitry is configured to decide whether to puncture an
uplink data transmission coinciding with the transmission time t
with the sounding reference signal transmission, based on the DRX
status of the user equipment at the predefined earlier time
instance relative to the transmission time t.
17. The user equipment of claim 16, wherein the uplink data
transmission is to be sent on a Physical Uplink Shared Channel
(PUSCH).
18. The user equipment of claim 16, wherein, when the processing
circuit decides to puncture the uplink data transmission, the
processing circuit is configured to puncture a last symbol of the
uplink data transmission with the sounding reference signal
transmission.
19. The user equipment of claim 11, wherein the processing circuit
is configured to decide whether to send the uplink transmission in
further dependence on whether another uplink transmission from the
user equipment coincides with the transmission time t.
20. The user equipment of claim 11, wherein the processing
circuitry is configured to decide to base the transmission decision
at the transmission time t on the DRX status of the user equipment
at the predefined earlier time instance in dependence on there
having been a change in an active time of the user equipment for
DRX operation, due to radio access network node signaling or radio
access network node data transmission to the user equipment.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 14/238,393 filed Feb. 11, 2014, which is a US National Phase
Application of PCT/SE2012/050490 filed May 9, 2012, which claims
priority to U.S. Provisional Application No. 61/522,981 filed Aug.
12, 2011.
TECHNICAL FIELD
[0002] Embodiments herein relate to a user equipment and methods
therein. In particular, it relates to deciding whether or not to
send an uplink transmission to a radio access network node.
BACKGROUND
[0003] Mobile Communications Systems
[0004] In a typical cellular radio system, wireless terminals, also
known as mobile stations and/or User Equipments (UEs), communicate
via a Radio Access Network (RAN) to one or more core networks. The
radio access network covers a geographical area which is divided
into cell areas. Each cell area is served by a base station, e.g.,
a Radio Base Station (RBS), which in some networks may also be
called, for example, a "NodeB" in Universal Mobile
Telecommunications System (UMTS) or "eNodeB" Long Term Evolution
(LTE). A cell is a geographical area where radio coverage is
provided by the radio base station equipment at a base station
site. The base stations communicate over the air interface
operating on radio frequencies with the user equipments within
range of the base stations.
[0005] In some versions of the radio access network, several base
stations are typically connected, e.g., by landlines or microwave,
to a controller node, such as a Radio Network Controller (RNC) or a
Base Station Controller (BSC), which supervises and coordinates
various activities of the plural base stations connected thereto.
The radio network controllers are typically connected to one or
more core networks.
[0006] The UMTS is a third generation mobile communication system,
which evolved from the second generation (2G) Global System for
Mobile Communications (GSM). The UMTS terrestrial radio access
network (UTRAN) is essentially a radio access network using
wideband code division multiple access for user equipments. In a
forum known as the Third Generation Partnership Project (3GPP),
telecommunications suppliers propose and agree upon standards for
third generation networks and UTRAN specifically, and investigate
enhanced data rate and radio capacity. Specifications for the
Evolved Packet System (EPS) have been completed within the 3rd 3GPP
to be continued in the coming 3GPP releases. The EPS comprises the
Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also
known as the Long Term Evolution (LTE) radio access, and the
Evolved Packet Core (EPC), also known as System Architecture
Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP
radio access technology wherein the radio base station nodes are
directly connected to the EPC core network rather than to RNC
nodes. In general, in E-UTRAN/LTE the functions of an RNC node are
distributed between the radio base stations nodes, e.g., eNodeBs in
LTE, and the core network. As such, the RAN of an EPS system has an
essentially "flat" architecture comprising radio base station nodes
that are not controlled by the RNC nodes.
[0007] Discontinuous Reception DTX
[0008] Long Term Evolution (LTE) supports Discontinuous Reception
(DRX) to enable a user equipment power savings by turning off some
or all of the radio circuitry of the user equipment, thereby
increasing the battery life time of the user equipment. The DRX
function is configured and controlled by the radio access network.
The user equipment behavior with respect to DRX is based on a set
of rules that define when the user equipment shall monitor a
Physical Downlink Control Channel (PDCCH) for scheduling grants and
assignments and when the user equipment shall and shall not
transmit certain uplink control signaling and uplink sounding
reference signals. The DRX function is characterized by a DRX cycle
and a number of timers that decide if the user equipment is in
active time or not. These timers include the on-duration timer, an
inactivity timer, and a retransmission timer. The user equipment
monitors the PDCCH at the beginning of every DRX cycle for the
entire on-duration period and additionally stays awake according to
the DRX timers. Whenever the user equipment receives an assignment
or grant indicating a new transmission from the radio access
network, it starts or restarts the inactivity timer and continues
to monitor the PDCCH until the timer expires. Moreover, to ensure
the Hybrid Automatic Repeat Request (HARQ) operation, the user
equipment also listens for grants for possible retransmissions in
UL and for possible retransmissions in DL as soon as a
retransmission can be expected. There are also periods when the
user equipment is in active time after transmission of a scheduling
request and during parts of the random access procedure.
[0009] According to LTE Medium Access Control (MAC) 36.213 Release
8, when DRX is configured, the user equipment shall for each
subframe: [0010] During the Active Time, for a PDCCH-subframe, if
the subframe is not required for uplink transmission for
half-duplex FDD UE operation and if the subframe is not part of a
configured measurement gap: --Monitor the PDCCH. Half-duplex FDD is
when a subframe is used for the user equipment to switch between
transmit and receive, i.e. same circuitry is used for both DL and
UL.
[0011] The MAC protocol is a protocol that handles e.g. scheduling
information and HARQ. DRX hence primarily regulates the downlink
monitoring of the user equipment. For further battery saving,
however, periodic uplink control signaling such as periodic Channel
State Information (CSI) reporting and periodic Sounding Reference
Signals (SRS) is also limited by DRX. Sounding reference signals
(SRS) are transmitted to enable improved channel estimation
[0012] According to LTE MAC, when DRX is configured, the user
equipment shall for each subframe. [0013] When not in Active Time,
type-0-triggered SRS shall not be reported. Type-0-triggered
SRS=periodic sounding reference signal. [0014] If Channel Quality
Indication (CQI) masking, also referred to as cqi-Mask, is setup by
upper layers, in this case upper layer is RRC, [0015] when on
duration timer is not running. CQI, Precoding Matrix Indicator
(PMI), Rank Indication (RI) and/or Precoder Type Indication (PTI)
on Physical Uplink Control Channel (PUCCH) shall not be reported.
The onDurationTimer together with the start of the DRX cycle decide
the on duration period. That is, if onDurationTimer=4, e.g., the
onDuration period will be from the start of the DRX cycle and 4
subframes onwards. [0016] Else: when not in Active Time,
CQI/PMI/RI/PTI on PUCCH shall not be reported.
[0017] Active Time
[0018] Active time for the user equipment is defined by a number of
timers and conditions:
[0019] According to MAC LTE, when a DRX cycle is configured, the
Active Time includes the time while: [0020] on duration timer or
DRX-inactivity timer or DRX-retransmission timer or mac-contention
resolution timer, as described in sub clause 5.1.5, in the LTE MAC
specification, is running; or [0021] a Scheduling Request is sent
on PUCCH and is pending, as described in subclause 5.4.4 in the LTE
MAC specification; or [0022] an uplink grant for a pending HARQ
retransmission can occur and there is data in the corresponding
HARQ buffer; or [0023] a PDCCH indicating a new transmission
addressed to a Cell Radio Network Temporary ID (C-RNTI) of the user
equipment has not been received after successful reception of a
Random Access Response for a preamble not selected by the user
equipment, as described in sub clause 5.1.4 in the LTE MAC
specification. The preamble may be referred to as a Random access
preamble.
[0024] The starting and stopping of timers is specified in the LTE
MAC specification cited above:
[0025] According to the LTE MAC protocol, when DRX is configured,
the user equipment shall for each subframe: [0026] If a HARQ RTT
Timer expires in this subframe and the data in the soft buffer of
the corresponding HARQ process was not successfully decoded, [0027]
start a DRX-Retransmission Timer for a corresponding HARQ process.
[0028] If a DRX Command MAC control element is received, --stop the
on duration timer, and [0029] stop the DRX-Inactivity Timer. [0030]
If drx-InactivityTimer expires or a DRX Command MAC control element
is received in this subframe: [0031] If the Short DRX cycle is
configured, [0032] start or restart drxShortCycleTimer; and [0033]
use the Short DRX Cycle. [0034] Else, use the Long DRX cycle.
[0035] If a DRX Short Cycle Timer expires in this subframe, [0036]
use the Long DRX cycle. [0037] If the Short DRX Cycle is used and
[(SFN*10)+subframe number] modulo (shortDRX-Cycle)=(drxStartOffset)
modulo (shortDRX-Cycle); or [0038] If the Long DRX Cycle is used
and [(SFN*10)+subframe number] modulo (long DRX-Cycle)=DRX Start
Offset, --start on duration timer, [0039] during the Active Time,
for a PDCCH-subframe, if the subframe is not required for uplink
transmission for half-duplex FDD UE operation and if the subframe
is not part of a configured measurement gap: --monitor the PDCCH;
and [0040] if the PDCCH indicates a downlink transmission or if a
downlink assignment has been configured for this subframe: [0041]
start the HARQ Round Trip Time (RTT) Timer for a corresponding HARQ
process; and [0042] stop the DRX-Retransmission Timer for the
corresponding HARQ process. [0043] If the PDCCH indicates a new
transmission, downlink or uplink: --start or restart the
DRX-Inactivity Timer. [0044] When not in Active Time,
type-0-triggered SRS shall not be reported.
[0045] This means that the timers above are stopped or started by
events such as reception of a PDCCH grant or assignment, or
Downlink (DL) Shared Channel (SCH) transmissions. There is also a
DRX command MAC control element that may put the user equipment
directly out of active time. Some of these events are not known to
the user equipment in advance and hence the user equipment may be
in active time in t=n and not know that it will no longer be in
active time in t=n+1 due to, e.g., transmissions from the
network.
[0046] Regardless of whether the user equipment is monitoring PDCCH
or not, the user equipment receives and transmits HARQ feedback and
transmits type-1-triggered SRS when such is expected.
[0047] Layer-1 details of periodic SRS and PUCCH A/N
[0048] Due to a single-carrier property of the Release-8 LTE
uplink, special rules apply when the timing is such that two uplink
transmissions would otherwise coincide, e.g.,
[0049] 1) HARQ A/N acknowledgement ("ack" or "A")/negative
acknowledgement ("nack" or "N") for a downlink transmission at the
same time as a periodic CSI report, or
[0050] 2) a PUSCH transmission at the same time as an SRS
transmission.
[0051] Concerning the Foregoing in More Detail:
[0052] A HARQ A/N on PUCCH for a downlink transmission is
transmitted on layer 1 using PUCCH format 1a/1b, 1a/1b are formats
for sending one and two bits of A/N info, respectively. If
coinciding in time with a periodic CSI report, the HARQ A/N and the
periodic CSI report are multiplexed and transmitted using PUCCH
format 2a/2b, 2a/2b are formats for sending periodic CSI report and
optionally multiplexed A/N info.
[0053] A PUSCH transmission normally uses all symbols of a
subframe. If coinciding in time with a periodic SRS transmission,
which uses the last symbol of the subframe, the PUSCH transmission
is punctured such that all symbols but the last are used for PUSCH
and in the last symbol, SRS is transmitted instead of PUSCH. The
puncturing of PUSCH occurs whenever the PUSCH coincides in
frequency with the cell SRS bandwidth, regardless of whether or not
the user equipment is itself transmitting SRS, and whenever the
user equipment is itself transmitting SRS, regardless of the
frequency location of the PUSCH transmission.
[0054] However, a disadvantage is that if transmissions in a
subframe n end active time or start active time in subframe n, the
existing rule that the user equipment decides what to transmit
based on the DRX status in subframe n, not yet known in the user
equipment, does not allow processing time for this user equipment,
which makes it hard to implement the solution above.
SUMMARY
[0055] It is therefore an object of embodiments herein to provide
an improved way of handling uplink transmissions in a user
equipment configured with DRX.
[0056] According to a first aspect of embodiments herein, the
object is achieved by a method in a user equipment for deciding
whether or not to send an uplink transmission to a radio access
network node. The user equipment and radio access network node are
comprised in a communications network. The user equipment is
configured with Discontinuous Reception. DRX, to be in active time
or not be in active time. The user equipment decides whether or not
to send the uplink transmission at a transmission time t, based on
whether the user equipment was in active time or not at a
predefined earlier time instance relative to the transmission time
t.
[0057] According to a second aspect of embodiments herein, the
object is achieved by a user equipment for deciding whether or not
to send an uplink transmission to a radio access network node. The
user equipment and radio access network node are intended to be
comprised in a communications network. The user equipment is
configured with Discontinuous Reception, DRX, to be in active time
or not be in active time. The user equipment comprises a second,
layer entity configured to decide whether or not to send the uplink
transmission at a transmission time t, based on whether the user
equipment was in active time or not at a predefined earlier time
instance relative to the transmission time t.
[0058] Since the decision whether or not to send the uplink
transmission at a transmission time t, is based on whether the user
equipment was in active time or not at a predefined earlier time
instance relative to the transmission time t, the user equipment
gets enough time until the time t, to allow the user equipment the
processing time required.
[0059] This results in an improved way of handling uplink
transmissions in a user equipment configured with DRX.
[0060] With these embodiments, the user equipment is requested to
send uplink transmission at certain well defined times and these
transmission times are also known by the radio access network node,
which means that it is possible to convey signaling information
from the user equipment to the radio access network node in a
predictable way, and thereby avoid any optional behavior which
would allow the user equipment to not perform uplink transmission
when the signaling information from the user equipment is
needed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0061] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
description of preferred embodiments as illustrated in the
accompanying drawings in which reference characters refer to the
same parts throughout the various views. Examples of embodiments
herein are described in more detail with reference to attached
drawings in which:
[0062] FIG. 1 is a schematic block diagram illustrating a
communications network.
[0063] FIG. 2 is a flowchart depicting embodiments of a method in a
user equipment.
[0064] FIG. 3 is a schematic block diagram illustrating embodiments
of a user equipment.
DETAILED DESCRIPTION
[0065] Embodiments will be exemplified in the following
non-limiting description.
[0066] As part of evaluation of embodiments herein, a problem shall
first be identified and discussed. A user equipment always requires
time to process commands, signalling, or bits that it receives from
a radio access network node serving the user equipment, before the
user equipment can act on the received information such as new
transmissions or grants for new transmissions or commands to stop
active time. Consequently, even if transmissions in a subframe n
end active time or start active time in subframe n, the user
equipment will not know that it is indeed in active time until a
subframe n+x for some positive value of x. In addition to the
processing delay on received information, the user equipment also
needs processing time to prepare its uplink transmissions, i.e. its
transmissions to the radio access network node. Hence, if an uplink
transmission is due in subframe n, the user equipment will need to
know in advance, in subframe n-y for some positive value of y, what
the user equipment is supposed to transmit. The existing rule that
the user equipment decides what to transmit based on the DRX status
in subframe n, not yet known in the user equipment, does not allow
for this user equipment processing time to prepare for the
transmission.
[0067] Some degree of freedom is needed in what the user equipment
is expected to transmit after an active time has ended or has
started or has been prolonged, due to an event from the radio
access network node not known in the user equipment until the event
which caused the change in active time has been made known in the
user equipment. In the LTE MAC protocol, there is an exception on
the PUCCH CSI reporting, such exception being quoted as
follows:
[0068] A user equipment may optionally choose to not send
CQI/PMI/RI/PTI reports on PUCCH and/or type-0-triggered SRS
transmissions for up to 4 subframes following a PDCCH indicating a
new uplink or downlink transmission received in the last subframe
of an active time. A choice not to send CQI/PMI/RI/PTI reports on
PUCCH and/or type-0-triggered SRS transmissions is not applicable
for subframes where an on duration timer is running.
[0069] The radio access network node expects transmissions from the
user equipment according to the standard. For example, if the user
equipment is in active time in subframe n, it is expected to
transmit periodic CSI on the PUCCH and it is expected to transmit
sounding reference signals SRS, if CSI or SRS is due, even if the
user equipment is in active time due to a recent prolongation of
active time from the reception of a new downlink assignment or
uplink grant. Also, if the user equipment is not in active time in
subframe n, it is expected not to transmit periodic CSI on PUCCH
and it is expected not to transmit SRS when such is due, even if
the user equipment has just recently been put in non-active time.
If the user equipment is, in addition, expected to transmit a HARQ
A/N for a downlink transmission, or a PUSCH transmission, the
selection of format for the HARQ A/N together with the PUSCH
depends on if the user equipment is in active time or not. HARQ A/N
together with a PUSCH transmission will not change depending on
active time. But for PUCCH, if a CSI is sent or not, depending on
active time, and together with a HARQ A/N the format will be
different. Format 2a/2b may be used if both HARQ A/N and CSI is
sent, and format 1a/1Bb may be used if only HARQ A/N is sent.
[0070] Hence, the decoding in the eNB, relies on the uplink
transmission having a certain format. The problem is that the
decoding fails if the format assumed is not correct.
[0071] Embodiments herein relate to telecommunications and
particularly to uplink (UL) transmissions over a radio or air
interface from a user equipment.
[0072] According to an aspect of the technology of embodiments
disclosed herein, for uplink transmissions, instead of acting
according to the DRX status, being in active time or not being in
active time, at the time of the actual uplink transmission, the
user equipment may decide the format and the sending or not sending
certain uplink transmissions such as SRS, PUCCH CSI and PUCCH A/N,
based on the DRX status of an earlier, predefined time instance,
with a fixed, known offset to the time of transmission. This shift
in time reference removes the dependency on a future state, the
state at actual transmission, for the user equipment when preparing
an uplink transmission.
[0073] As possible, but not necessary limiting, example features,
the shift in time reference may be applied only when the resulting
uplink transmission coincides in time with another uplink
transmission from the same user equipment and/or only when there
has been a change in DRX status due to signaling from the network,
i.e. from the radio access network node. The above two example
features may be applied separately, one not requiring the other, or
both at the same time.
[0074] FIG. 1 depicts a communications network 100 in which
embodiments herein may be implemented. The communications network
100 is a wireless communication network such as an LTE network or
any 3GPP cellular network, Wimax, Wi-Fi or any cellular or wireless
network or system.
[0075] The communications network 100 comprises one or more radio
network nodes such as a radio access network node 110. The radio
access network node 110 serves a cell 115. The radio access network
node 110 is an access point that may be a radio base station. The
logical function(s) provided by such a radio base station may be
e.g. the functions of an eNB, an eNodeB, or a Home NodeB, a Home
eNode B, or any other network nodes capable to serve a user
equipment or a machine type communication device in a wireless
network.
[0076] The communications network 100 further comprises a user
equipment 120. The user equipment 120 is served by the radio access
network node 110 when the user equipment 120 is located in the cell
115. The user equipment 120 user equipment comprises a
communications interface 125 (which is shown in FIG. 3) adapted to
communicate with the radio access network node over a radio link
130.
[0077] As used herein, the user equipment 120 may be referred to as
terminal or wireless terminal which may be a mobile station such as
a mobile telephone, a cellular telephone, a laptop or surf plate
with wireless capability, e.g., mobile termination, and thus may
be, for example, a portable, pocket, hand-held, computer-included,
or car-mounted mobile device which communicates voice and/or data
via a radio access network. Moreover, the user equipment 120 may be
a fixed terminal which communicates voice and/or data via a radio
access network.
[0078] In example embodiments of such methods and apparatus the
user equipment 120 decides on and transmits uplink control
signaling and/or sounding reference signals to the radio access
network node 110 over the radio or air interface 130.
[0079] The user equipment 120 is configured with DRX to be in
active time or not be in active time. E.g. When onDurationTimer is
running, the user equipment is in active time. When onDurationTImer
is not running, the user equipment may be in active time or not in
active time, depending on other timers and other conditions.
[0080] The UE 120 may selectively or intermittently enter active
time to communicate with the radio access node 110, and otherwise
stays in sleep mode or inactive time.
[0081] In an example embodiment and mode the radio access network
signaling may incur a start or stop of a DRX timer, starting or
ending active time, or the radio access network signaling may be a
DRX command MAC control element ending active time.
[0082] Embodiments of a method in the user equipment 120 for
deciding whether or not to send an uplink transmission to the radio
access network node 110, will now are described with reference to a
flowchart depicted in FIG. 2. As mentioned above the user equipment
120 and radio access network node 110 are comprised in the
communications network 100. The user equipment 120 is configured
with DRX to be in active time or not be in active time. The method
comprises the following actions, which actions may be taken in any
suitable order. Dashed lines of some boxes in FIG. 4 indicate that
this action is not mandatory.
[0083] Action 201
[0084] The user equipment 120 decides whether or not to send the
uplink transmission at a transmission time t. This decision is
according to embodiments herein based on whether the user equipment
120 was in active time or not at a predefined earlier time instance
relative to the transmission time t, t represents the point in time
when the transmission shall be performed. According to some
embodiments this means that the decision is based on a DRX status
of an earlier, predefined time instance, with a fixed, known offset
to the time of transmission. I.e. earlier than the transmission
time t, for example 0.1-10 ms, typically 1-4 ms earlier than the
transmission time t. This decision being based on a DRX status
earlier than the time t removes the dependency on a future state,
i.e. the state at actual transmission at the time t, for the user
equipment 120 when preparing an uplink transmission. The decision
instead relies on a current state.
[0085] In some embodiments, the uplink transmission comprises
periodic uplink control signaling and/or transmission of a sounding
reference signal. Periodic uplink control signaling may be periodic
CSI and a sounding reference signal may be a predefined signal used
to measure the user equipment's channel.
[0086] The periodic uplink control signaling may comprise CSI,
comprising all of or any subsets of CQI, PMI, RI and PTI.
[0087] Action 202
[0088] Based on whether the user equipment 120 was in active time
or not at the predefined earlier time instance relative to the
transmission time t, the user equipment 120 may decide a format to
use for sending other uplink control signaling together with the
periodic uplink control signaling. This overcomes the problem of
unknown or wrong format leading to problems with decoding in the
base station 110. The format may e.g. be format 1a, format 1b,
format 2a, format 2b, etc. In some embodiments the other uplink
control signaling comprises HARQ and/or A/N feedback.
[0089] Action 203
[0090] In some embodiments the user equipment 120 decides whether
or not to puncture an uplink data transmission to enable sending of
sounding reference signals, based on whether the user equipment 120
was in active time or not at a predefined earlier time instance
relative to the transmission time t.
[0091] The uplink data transmission may be sent on a PUSCH.
[0092] In some of these embodiments a last symbol of the uplink
data transmission to be sent on a PUSCH is punctured to enable
sending of sounding reference signals in the last symbol.
[0093] In some embodiments, any of the action steps 201, 202 or 203
above that are based on whether the user equipment 120 was in
active time or not at a predefined earlier time instance relative
to the transmission time t, are applied at time instances when
there are other uplink transmissions from the user equipment 120 to
the radio access network node 110 coinciding in time. In some
embodiments said actions 201, 202, 203 are performed only in these
time instances.
[0094] In some embodiments any of the action steps 201, 202, 203
being based on whether the user equipment 120 was in active time or
not at a predefined earlier time instance relative to the
transmission time t, are applied at time instances when there has
been a change in the active time such as e.g. prolongation of
active time or end of active time, due to radio access network node
signaling or radio access network node data transmission to the
user equipment 120. In some embodiments said action steps 201, 202,
203 are performed only in these time instances.
[0095] The above two example features may be applied separately,
one not requiring the other, or both at the same time.
[0096] In the embodiments wherein said actions 201, 202, 203 are
performed only in the above mentioned time instances, the decision
and transmission of uplink control signaling and/or sounding
reference signals at other time instances than the above mentioned
time instances, may be based on the user equipment 120 being in
active time or not at the transmission time t.
[0097] As mentioned above, for uplink transmissions according to
embodiments disclosed herein, instead of acting according to the
DRX status, being in active time or not being in active time, at
the time of the actual uplink transmission, the user equipment may
decide the format and the sending or not sending certain uplink
transmissions such as SRS, PUCCH CSI and PUCCH A/N, based on the
DRX status of an earlier, predefined time instance, with a fixed,
known offset to the time of transmission. This shift in time
reference, removes the dependency on a future state for the user
equipment when preparing an uplink transmission. In this way a
practically realizable way of handling uplink transmissions is
provided which implies a more efficient way of using a spectrum in
a wireless network. In this way, the handling uplink transmissions
in a user equipment configured with DRX has been improved.
[0098] To perform the method actions for deciding whether or not to
send an uplink transmission to the radio access network node 110
described above in relation to FIG. 2, the user equipment 120
comprises the following arrangement depicted in FIG. 3. FIG. 3
depicts by a broken, double-dotted line, means to perform actions
such as the actions 201, 202 and/or 203. As mentioned above, the
user equipment 120 and the radio access network node 110 are
intended to be comprised in the communications network 100. The
user equipment 120 is configured with DRX to be in active time or
not be in active time.
[0099] The user equipment 120 comprises a second layer entity 310
configured to decide whether or not to send the uplink transmission
at a transmission time t, based on whether the user equipment 120
was in active time or not at a predefined earlier time instance
relative to the transmission time t. The uplink transmission may
comprise periodic uplink control signaling and/or transmission of a
sounding reference signal. The second layer entity may be a MAC
layer entity.
[0100] The periodic uplink control signaling may comprise CSI
comprising all of or any subsets of CQI, PMI, RI and, PTI.
[0101] In some embodiments, the second layer entity 310 is further
configured to decide whether or not to puncture an uplink data
transmission to enable sending of sounding reference signals, based
on whether the user equipment 120 was in active time or not at a
predefined earlier time instance relative to the transmission time
t. The uplink data transmission may be intended to be sent on a
PUSCH. In some of these embodiments a last symbol of the uplink
data transmission intended to be sent on a PUSCH may be punctured
to enable sending of sounding reference signals in the last
symbol.
[0102] The user equipment 120 may further comprise a first layer
entity 320 configured to decide a format to use for sending other
uplink control signaling together with the periodic uplink control
signaling, based on whether the user equipment 120 was in active
time or not at a predefined earlier time instance relative to the
transmission time t. In some embodiments the other uplink control
signaling comprises HARQ, and/or A/N, feedback. The first layer
entity 320 may be a physical layer entity.
[0103] The second layer entity 310 and/or the first layer entity
320 may further be configured to perform the decisions being based
on whether the user equipment 120 was in active time or not at a
predefined earlier time instance relative to the transmission time
t, at time instances when there are other uplink transmissions from
the user equipment 120 to the radio access network node 110
coinciding in time.
[0104] The second layer entity 310 and/or the first layer entity
320 may further be configured to perform the decisions being based
on whether the user equipment 120 was in active time or not at a
predefined earlier time instance relative to the transmission time
t, at time instances when there has been a change in the active
time due to radio access network node 110 signaling or radio access
network node data transmission to the user equipment 120.
[0105] The above two example features may be applied separately,
one not requiring the other, or both at the same time.
[0106] In the example embodiment of FIG. 3, the broken,
double-dotted line may also depict the fact that the second layer
entity 310 such as the MAC layer entity and the first layer entity
320 such as the physical layer entity may comprise, be realized by,
and/or be included in electronic circuitry and particularly by a
platform, such platform being framed by the broken, double-dotted
line. The terminology "platform" is a way of describing how the
functional units or entities framed thereby may be implemented or
realized by machine including electronic circuitry. One example
platform is a computer implementation wherein one or more of the
framed elements are realized by one or more processors such as a
processor 340 which execute coded instructions and which use
non-transitory signals in order to perform the various acts
described herein. In such a computer implementation the user
equipment 120 may comprise, in addition to the processor(s), a
memory section, such as a memory 350 which in turn may comprise a
random access memory; a read only memory; an application memory;
and any other memory such as cache memory, for example. The memory
section, e.g., the application memory, may store, e.g., coded
instructions which may be executed by the processor to perform acts
described herein. The platform may also comprise other input/output
units or functionalities, such as a keypad; an audio input device,
e.g., microphone; a visual input device, e.g., camera; a visual
output device; and an audio output device, e.g., a speaker. Other
types of input/output devices may also be connected to or comprise
the user equipment 120. Another example platform suitable for the
user equipment 120 is that of a hardware circuit, e.g., an
application specific integrated circuit (ASIC) wherein circuit
elements are structured and operated to perform the various acts
described herein.
[0107] The following is applicable to any of the embodiments
above.
[0108] Implementation of embodiments herein according to LTE
MAC
[0109] A possible way to implement embodiments disclosed herein in
the LTE MAC specification 36.321 section 5.7 for DRX is shown
below, with underlining showing modifications according to
embodiments herein, to the existing specification
[0110] When DRX is configured, the user equipment 120 referred to
as UE 120 below, shall for each subframe: [0111] when not in Active
Time in subframe n-k, where k is the most recent in time in the set
K, type-0-triggered SRS shall not be reported. K is defined in
Table 10.1.3.1-1 in 3GPP TS 36.213 V10.1.0 from the MAC
specification (2011-03) see below. Set K defines the subframes
where a PDCCH may have occurred for a PDSCH transmission, occurred
here means a PDCCH indicating a transmission UL or DL. [0112] if
CQI masking (cqi-Masn k) is setup by upper layers: [0113] when
onDurationTimer is not running, CQI/PMI/RI/PTI on PUCCH shall not
be reported. [0114] else: [0115] when not in Active Time in
subframe n-k, where k is the most recent in time in the set K,
CQI/PMI/RI/PTI on PUCCH shall not be reported.
[0116] Regardless of whether the UE 120 is monitoring PDCCH or not,
the UE 120 receives and transmits HARQ feedback and transmits
type-1-triggered SRS when such is expected.
TABLE-US-00001 TABLE 10.1.3.1-1 Downlink association set index K:
{k.sub.0, k.sub.1, . . . k.sub.M-1} for TDD UL-DL Subframe n
Configuration 0 1 2 3 4 5 6 7 8 9 0 -- -- 6 -- 4 -- -- 6 -- 4 1 --
-- 7, 6 4 -- -- -- 7, 6 4 -- 2 -- -- 8, 7, 4, 6 -- -- -- -- 8, 7,
-- -- 4, 6 3 -- -- 7, 6, 11 6, 5 5, 4 -- -- -- -- -- 4 -- -- 12, 8,
7, 11 6, 5, -- -- -- -- -- -- 4, 7 5 -- -- 13, 12, 9, 8, -- -- --
-- -- -- -- 7, 5, 4, 11, 6 6 -- -- 7 7 5 -- -- 7 7 --
[0117] NOTE: The UE 120 may optionally choose to not send
CQI/PMI/RI/PTI reports on PUCCH and/or type-0-triggered SRS
transmissions for up to 4 subframes following a PDCCH indicating a
new Uplink (UL) or Downlink (DL) transmission, received in subframe
n-i, where n is the last subframe of Active Time and i is an
integer value from 0 to 3. After Active Time is stopped due to the
reception of a PDCCH or a MAC control element the UE 120 may
optionally choose to continue sending CQI/PMI/RI/PTI reports on
PUCCH and/or SRS transmissions for up to 4 subframes. The choice
not to send CQI/PMI/RI/PTI reports on PUCCH and/or type-0-triggered
SRS transmissions is not applicable for subframes where
onDurationTimer is running and is not applicable for subframes n-i
to n, and is not applicable for subframes where the UE 120 is
transmitting on UL-Shared Channel (SCH) or transmitting HARQ
feedback on PUCCH.
[0118] For uplink transmissions according to embodiments disclosed
herein, instead of acting according to the DRX status, being in
active time or not being in active time, at the time of the actual
uplink transmission, the user equipment may decide the format and
the sending or not sending certain uplink transmissions such as
SRS. PUCCH CSI and PUCCH A/N, based on the DRX status of an
earlier, predefined time instance, with a fixed, known offset to
the time of transmission. This shift in time reference, removes the
dependency on a future state for the user equipment when preparing
an uplink transmission. In this way a practically realisable way of
handling uplink transmissions is provided which implies a more
efficient way of using a spectrum in a wireless network. In this
way the handling uplink transmissions in a user equipment
configured with DRX has been improved.
[0119] Alternative implementations of embodiments herein.
[0120] The technology disclosed herein comprises many embodiments
and variations and example implementations. The subframe at the
predefined earlier time instance relative to the transmission time
t may be referred to as n-k. For example the "k" in "n-k" may be
defined as any fixed, predefined value larger than zero, large
enough to allow the user equipment 120 the processing time
required.
[0121] Further, the condition on transmitting or not transmitting
the CSI on PUCCH or the SRS may be stated in terms of what timers
are running or not running or other conditions, which can however
be summarized as "the user equipment 120 is in active time" or "the
user equipment is not in active time". For k set such that n-k
equals the point in time when the grant was received for the PUSCH
transmission, or when the PDSCH transmission resulting in the HARQ
A/N was received, the condition may also be written as the user
equipment 120 being in active time when the grant was received for
the PUSCH transmission, or when the PDSCH transmission resulting in
the HARQ A/N was received.
[0122] Moreover, with dynamic scheduling, the user equipment 120
has to monitor the PDCCH to receive dedicated information from the
eNB, such as the radio access network node 110. Hence, normally the
user equipment 120 is in active time when receiving the PDCCH. This
means that when the user equipment 120 is scheduled with dynamic
scheduling, as opposed to semi-persistently scheduled, the
condition on active time in the time when the downlink assignment
or uplink grant was received, is equivalent to stating that
periodic CSI and/or SRS shall be transmitted when coinciding with a
HARQ A/N transmission or a PUSCH transmission, respectively. For
semipersistent scheduling, the condition may be stated as "had the
user equipment 120 been in active time at the point in time when
the downlink assignment or uplink grant would have been received,
had the user equipment 120 not been scheduled semi-persistently.
SPS does not have a grant/assignment but still causes the same
UL/DL transmissions which need to be handled.
[0123] The embodiments of technology disclosed herein and
encompassed hereby has numerous advantages. Example, non-limiting
advantages include: [0124] Providing the user equipment 120 enough
time to prepare an uplink transmission. [0125] Resulting in a
known, predefined uplink transmission for the user equipment, such
that the network knows how to decode the uplink transmission.
According to prior art, a radio access network node trying to
decode an uplink transmission with the wrong assumption will most
likely lead to failure to decode the transmission. If a HARQ A/N is
not received, unnecessary retransmissions or not enough
retransmission of a packet will follow. If a PUSCH transmission is
not decoded correctly, unnecessary retransmissions follow, possibly
also leading higher-layer (RLC) retransmissions. This will not
happen in radio access networks designed according to embodiments
herein.
[0126] For example, it will be appreciated by those skilled in the
art that block diagrams herein can represent conceptual views of
illustrative circuitry or other functional units embodying the
principles of the technology. Similarly, it will be appreciated
that any flow charts, state transition diagrams, pseudocode, and
the like represent various processes which may be substantially
represented in computer readable medium and so executed by a
computer or processor, whether or not such computer or processor is
explicitly shown.
[0127] The functions of the various elements including functional
blocks, including but not limited to those labeled or described as
"computer", "processor" or "controller", may be provided through
the use of hardware such as circuit hardware and/or hardware
capable of executing software in the form of coded instructions
stored on computer readable medium. Thus, such functions and
illustrated functional blocks are to be understood as being either
hardware-implemented and/or computer-implemented, and thus
machine-implemented.
[0128] In terms of hardware implementation, the functional blocks
may include or encompass, without limitation, digital signal
processor (DSP) hardware, reduced instruction set processor,
hardware (e.g., digital or analog) circuitry including but not
limited to application specific integrated circuit(s) [ASIC], and
(where appropriate) state machines capable of performing such
functions.
[0129] In terms of computer implementation, a computer is generally
understood to comprise one or more processors or one or more
controllers, and the terms computer and processor and controller
may be employed interchangeably herein. When provided by a computer
or processor or controller, the functions may be provided by a
single dedicated computer or processor or controller, by a single
shared computer or processor or controller, or by a plurality of
individual computers or processors or controllers, some of which
may be shared or distributed. Moreover, use of the term "processor"
or "controller" shall also be construed to refer to other hardware
capable of performing such functions and/or executing software,
such as the example hardware recited above.
[0130] Although the description above contains many specificities,
these should not be construed as limiting the scope of the
invention but as merely providing illustrations of some of the
presently preferred embodiments of this invention. It will be
appreciated that the scope of the present invention fully
encompasses other embodiments which may become obvious to those
skilled in the art, and that the scope of the present invention is
accordingly not to be limited. Reference to an element in the
singular is not intended to mean "one and only one" unless
explicitly so stated, but rather "one or more." When using the word
"comprise" or "comprising" it shall be interpreted as non-limiting,
i.e. meaning "consist at least of". All structural and functional
equivalents to the elements of the above-described embodiments that
are known to those of ordinary skill in the art are expressly
incorporated herein by reference and are intended to be encompassed
hereby. Moreover, it is not necessary for a device or method to
address every problem sought to be solved by the present invention,
for it to be encompassed hereby.
[0131] In the description above, for purposes of explanation and
not limitation, specific details are set forth such as particular
architectures, interfaces, techniques, etc., to provide a thorough
understanding of the embodiments herein. However, it will be
apparent to those skilled in the art that the present invention may
be practiced in other embodiments that depart from these specific
details. That is, those skilled in the art will be able to devise
various arrangements which, although not explicitly described or
shown herein, embody the principles of the embodiments herein and
are included within its scope. In some instances, detailed
descriptions of well-known devices, circuits, and methods are
omitted so as not to obscure the description of the embodiments
herein with unnecessary detail. All statements herein reciting
principles, aspects, and embodiments of the embodiments herein, as
well as specific examples thereof, are intended to encompass both
structural and functional equivalents thereof. Additionally, it is
intended that such equivalents include both currently known
equivalents as well as equivalents developed in the future, i.e.,
any elements developed that perform the same function, regardless
of structure.
* * * * *