FIELD OF THE INVENTION
Embodiments of the invention relate to wireless communication. Embodiments of the
invention relate in particular to a mobile terminal configured for communication with a
wireless network, to a wireless network, to a communication system and methods
performed by such devices in which power consumption of a modem of the mobile
terminal is controlled.
BACKGROUND OF THE INVENTION
With increasing popularity of mobile voice and data communication, there is an ever
increasing demand for high-speed data communication. Modern mobile terminals of
a communication network, e.g. smartphones, have advanced processing capabilities.
The mobile terminals can run a wide variety of applications. These applications in
clude social networks, e-mail services, update clients such as news update centers
or weather forecasts, without being limited thereto.
Some of these applications continue to operate even when the mobile terminal is not
in use. Some of these applications may continue to operate continuously or quasicontinuously
even when a screen of the mobile terminal is switched off. In this case,
the application(s) may continue to transmit or receive data via a modem of the mobile
terminal. This causes the processor(s) of the mobile terminal which execute the a p
plication^) to run repeatedly. Moreover, also the modem is switched on repeatedly to
allow the application(s) to transmit or receive data. This reduces battery lifetime while
providing only limited benefit to the user when the mobile terminal is not in use.
To mitigate the power consumption problems associated with data transfers initiated
by applications which are executed by the mobile terminal, the transmission of mes
sages by the application(s) over the modem may be restricted. This approach may
not be sufficient to allow the amount of data transfers received by application(s) on
the mobile terminal to be controlled in an efficient manner. When an application exe
cuted by the mobile terminal is associated with a large amount of push data traffic
towards the mobile terminal, an undesirably large amount of battery power may still
be drained from the battery while the mobile terminal is in a standby mode, for exam
ple.
To reduce modem power consumption, the mobile terminal may be set to different
states. For illustration, 3GPP specification TS 25.331 V 11.5.0 (201 3-03) entitled "3rd
Generation Partnership Project; Technical Specification Group Radio Access Net
work; Radio Resource Control (RRC); Protocol specification (Release 11)" defines
different RRC states in section 7.1 . While the mobile terminal may enter some of
these states autonomously, e.g. when a timer expires, the various parameters which
determine the RRC state of the mobile terminal or transitions between these states
are controlled by a node of the communication network. These techniques may still
not be adequate by themselves to address the power consumption problems associ
ated with continued modem usage of applications running on the mobile terminal. For
illustration, a social network or e-mail service or a news service running on the mobile
terminal may receive incoming push data traffic. This may cause the mobile te r
minal to make a transition from an idle mode in which it is RRC disconnected to an
RRC connected mode. The resulting modem activity reduces battery lifetime.
BRIEF SUMMARY OF THE INVENTION
There is a continued need in the art for devices and methods which mitigate the
problems associated with modem power consumption caused by application(s) exe
cuted by the mobile terminal.
According to embodiments, a mobile terminal initiated switching of a power mode to
a power saving mode is introduced. The mobile terminal may signal to the communi
cation network that it intends to enter a specific power saving mode. A set of several
power modes which reduce power consumption may be defined in addition to a regu
lar power mode, and the mobile terminal may signal to the communication network
which one of the power saving modes the mobile terminal intends to enter. In the
power modes which reduce power consumption, the mobile terminal may still be co n
figured to make transitions between different Radio Resource Control, RRC, states,
e.g. from the idle mode to the connected mode. Parameter settings associated with
the respective power mode may define parameters of layer 1, layer 2, and/or layer 3
signalling between mobile terminal and the communication network.
A mobile terminal according to an embodiment comprises a modem for communica
tion with a wireless network. The mobile terminal comprises a logic configured to se
lect a power mode from a plurality of power modes. The logic is configured to control
the modem to transmit a power mode change request which includes an indicator for
the selected power mode. The logic is configured to control the mobile terminal to
enter the selected power mode in response to receiving a power mode change re
sponse.
The logic may be configured to select the power mode in dependence on applications
executed by the mobile terminal to reduce data transfers to the mobile terminal
while the applications are executed by the mobile terminal.
The logic may be configured to select the power mode to reduce the data transfers to
the mobile terminal while the mobile terminal is not in use. The logic may be configured
to select the power mode to reduce the data transfers to the mobile terminal
while the mobile terminal is in a standby mode.
The mobile terminal may be configured to switch between different RRC states while
operating in the selected power mode.
The indicator for the selected power mode may be selected from a finite set of indica
tors. The set may include one unique indicator for each power mode. The set of ind i
cators may include more than two indicators. The set of indicators may include at
least four indicators.
The selected power mode and at least one other power mode of the plurality of pow
er modes may have different parameters for the first and/or second layer signalling of
the radio interface between the mobile terminal and the communication network.
The selected power mode and at least one other power mode of the plurality of pow
er modes may have different parameters for the third layer signalling of the radio in
terface between the mobile terminal and the communication network. The selected
power mode and at least one other power mode of the plurality of power modes may
have different DRX parameter settings, for example.
The different DRX parameter settings may comprise different DRX cycle lengths. Ad
ditionally or alternatively, the different DRX parameter settings may comprise different
inactivity timer values. Additionally or alternatively, the different DRX parameter
settings may comprise different paging cycles.
The mobile terminal may be configured to switch between an idle state and an RRC
connected state while operating in the selected power mode.
At least two power modes of the plurality of power modes may be distinguished from
each other in the number of DRX states. The logic may select one of these at least
two power modes. For illustration, a first power mode may have only one DRX state
while the mobile terminal is in the idle state. A second power mode may have two
different DRX states while the mobile terminal is in the idle state. The two different
DRX states may be an idle DRX state with long DRX cycle and an idle DRX state
with short DRX cycle.
At least two power modes of the plurality of power modes may have different protocol
procedures for the mobile terminal accessing the wireless network. The logic may
select one of these at least two power mode.
At least two power modes of the plurality of power modes may have different radio
parameters. At least two power modes of the plurality of power modes may have d if
ferent terminal output power classes. In one of the at least two power modes, trans
mission and/or reception may be limited to half duplex operation. The logic may se
lect one of these at least two power mode.
At least two power modes of the plurality of power modes may define different mobil
ity management procedure. For illustration, a first power mode may have more lim
ited cell change possibilities than a second power mode. The logic may select the
first power mode or the second power mode.
The mobile terminal may be configured to activate the modem for processing incom
ing data transfers with a timing which depends on the selected power mode while
operating in the selected power mode.
The mobile terminal may be configured to transmit the power mode change request
in an RRC Connection Establishment procedure or in an RRC Connection Recon
figuration procedure.
The mobile terminal may comprise a display. The logic may be configured to select
the power mode in dependence on whether the display is switched off. The logic may
be configured to select the power mode in dependence on whether the display is
switched off for at least a predetermined time period.
The mobile terminal may comprise at least one sensor. The logic may be configured
to select the power mode in dependence on whether the display is switched off and
in dependence on an output signal of the at least one sensor. The at least one sen
sor may comprise a motion sensor. The output signal of the motion sensor may be
used by the logic to determine whether the mobile terminal is in use and/or whether
the mobile terminal is being carried by a user. The logic may select the power mode
based on whether the mobile terminal is in use and/or whether the mobile terminal is
being carried by the user.
The logic may be configured to prevent an application from causing a data transmis
sion via the modem when the display is switched off. The logic may activate a firewall
of the mobile terminal between the application and the modem in dependence on
whether the display is switched off for at least a predetermined time period, to restrict
usage of the modem by the application for outgoing data transfers.
The power mode change request may comprise a plurality of indicator bits which in
clude the indicator for the selected power mode. The power mode change request
may comprise two indicator bits. The power mode change request may comprise
three indicator bits. Accordingly, up to four or up to eight different power modes may
be defined.
The logic may be configured to identify a further power mode in dependence on a
further power mode identifier included in a further power mode change request re
ceived by the mobile terminal. The further power mode change request is a networkinitiated
power mode change request. The logic may be configured to control the
modem to transmit a further power mode change response in response to receiving
the further power mode change request. The logic may be configured to control the
mobile terminal to enter the further power mode in response to receiving the further
power mode change request. This allows the mobile terminal to enter a power mode
selected by the communication network.
The mobile terminal may be user equipment. The user equipment may be configured
for communication with a Long Term Evolution (LTE) network. The mobile terminal
may be a mobile phone, e.g. a smartphone.
The mobile terminal may be a machine-to-machine (M2M) terminal. The mobile ter
minal may be configured to perform M2M communication via the wireless network.
According to another embodiment, a radio access network (RAN) node is provided.
The RAN node has a wireless interface. The RAN node has a processing device
coupled to the wireless interface. The wireless interface is configured to receive a
power mode change request from the mobile terminal. The processing device is co n
figured to determine which power state of a plurality of power states a mobile termi
nal intends to enter based on an indicator for the power state included in the power
mode change request. The processing device is configured to control the wireless
interface to transmit a power mode change response.
The RAN node may be configured to control data transfers to the mobile terminal in
accordance with the indicator for the power state included in the power mode change
request after transmitting the power mode change response.
The RAN node may be configured to reduce a number and/or rate of data transfers
to applications on the mobile terminal in accordance with the indicator for the power
state included in the power mode change request after transmitting the power mode
change response.
The RAN node may be configured to adjust a paging cycle for the mobile terminal
after transmitting the power mode change response.
The RAN node may be a base station. The RAN node may in particular be a NodeB
or an evolved NodeB (eNodeB).
A communication system according to an embodiment comprises the mobile terminal
of an embodiment and a radio access network. The radio access network may be
configured to receive the power mode change request from the mobile terminal. The
radio access network may be configured to identify the selected power mode based
on the indicator included in the power mode change request. The radio access net
work may be configured to transmit a power mode change response to the mobile
terminal. The radio access network may be configured to control data transfers to the
mobile terminal based on the selected power mode.
The radio access network may comprise a RAN node, e.g. a NodeB or eNodeB, configured
to perform the functions indicated above. The RAN node may be a RAN node
according to an embodiment.
A method of controlling a transition between power modes of a mobile terminal ac
cording to an embodiment comprises selecting, by the mobile terminal, a power
mode from a plurality of power modes. The mobile terminal transmits a power mode
change request over a wireless interface, the power mode change request includes
an indicator for the selected power mode. In response to receiving a power mode
change response, the mobile terminal enters the selected power mode by the mobile
terminal.
The power mode may be selected in dependence on applications executed by the
mobile terminal to reduce data transfers to the mobile terminal while the applications
are executed by the mobile terminal.
The data transfers to applications executed by the mobile terminal may be reduced
while the mobile terminal is not in use. The data transfers to applications executed by
the mobile terminal may be reduced while the mobile terminal is in a standby mode.
The mobile terminal may switch between different Radio Resource Control, RRC,
states while operating in the selected power mode.
The indicator for the selected power mode may be selected from a finite set of indica
tors, which includes respectively one indicator for each power mode.
The selected power mode and at least one other power mode of the plurality of pow
er modes may have different parameter settings for layer 1, layer 2, and/or layer 3
signalling between the mobile terminal and the communication network.
The different DRX parameter settings may comprise different DRX cycle lengths. Additionally
or alternatively, the different DRX parameter settings may comprise differ
ent inactivity timer values. Additionally or alternatively, the different DRX parameter
settings may comprise different paging cycles.
The method may comprise switching between an idle mode and an RRC connected
mode while the terminal operates in the selected power mode.
The method may comprise activating the modem for processing received data trans
fers with a timing which depends on the selected power mode while the mobile ter
minal operates in the selected power mode.
The power mode change request may be transmitted in an RRC Connection Establishment
procedure or in an RRC Connection Reconfiguration procedure.
The power mode may be selected in dependence on whether the display is switched
off. The power mode may be selected in dependence on whether the display is
switched off for at least a predetermined time period.
The power mode may be selected in dependence on whether the display is switched
off and in dependence on an output signal of the at least one sensor. The at least
one sensor may comprise a motion sensor. The output signal of the motion sensor
may be analyzed to determine whether the mobile terminal is in use and/or whether
the mobile terminal is carried by a user. The power mode may be selected based on
whether the mobile terminal is in use and/or whether the mobile terminal is carried by
the user.
The method may further comprise preventing an application from causing a data
transmission via the modem when the display is switched off. A firewall between the
application and the modem may be activated in dependence on whether the display
is switched off for at least a predetermined time period, to restrict usage of the mo
dem by the application for outgoing data transfers.
The power mode change request may comprise a plurality of indicator bits which in
clude the indicator for the selected power mode. The power mode change request
may comprise two indicator bits. The power mode change request may comprise
three indicator bits. Accordingly, up to four or up to eight different power modes may
be defined.
The method may comprise identifying a further power mode in dependence on a fur
ther power mode identifier included in a further power mode change request received
by the mobile terminal. The method may comprise controlling the modem to transmit
a further power mode change response in response to receiving the further power
mode change request. The method may comprise controlling the mobile terminal to
enter the further power mode in response to receiving the further power mode
change request. This allows the mobile terminal to enter a power mode selected by
the communication network.
The method may be performed by the mobile terminal of an embodiment.
Devices and methods according to embodiments allow a mobile terminal to initiate a
transition to a certain power mode having lower power consumption than the regular,
fully operative power mode. Incoming data transfers for applications executed on the
mobile terminal may thereby be reduced by selecting a power mode with lower mo
dem power consumption. The amount of time for which the modem must be switched
on to process incoming data transfers may be reduced. Battery lifetime may be im
proved.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will be described with reference to the accompanying
drawings in which the same or similar reference numerals designate the same or
similar elements.
Fig. 1 is a schematic view of a communication system according to an embodiment.
Fig. 2 is a flow chart of a method according to an embodiment.
Fig. 3, Fig. 4 and Fig. 5 are diagrams illustrating operation of a mobile terminal and a
radio access network node in a method according to an embodiment.
Fig. 6 is a diagram illustrating states of a mobile terminal between which the mobile
terminal may switch while operating in a selected power mode.
Fig. 7 is a block diagram representation of functional units of a mobile terminal according
to an embodiment.
Fig. 8 is a block diagram representation of a radio access network node according to
an embodiment.
Fig. 9 is a flow chart of a method according to an embodiment.
DESCRIPTION OF EMBODIMENTS
Exemplary embodiments of the invention will be described with reference to the
drawings. While some embodiments will be described in the context of specific fields
of application, e.g. in the context of exemplary radio access technologies, the em
bodiments are not limited to this field of application. The features of the various em
bodiments may be combined with each other unless specifically stated otherwise.
Fig. 1 is a schematic view of a communication system 1 according to an embodiment.
The communication system 1 comprises a mobile terminal 20. The communi
cation system 1 comprises a communication network 10 . The communication net
work 10 has a radio access network (RAN). The radio access network includes a plu
rality of base stations 11-1 3 . The base stations 11- 13 may be operatively coupled to
other nodes 14, 15 which may be provided in the radio access network or in a core
network (CN) of the communication network 10 . The specific configuration of the
communication network 10, of the base stations 11-1 3 and of the nodes 14, 15 de
pends on the communication standard. For illustration, the communication network
10 may be a Global System for Mobile Communications (GSM) network. In this case,
the RAN is a GSM EDGE Radio Access Network (GERAN), with the nodes 14, 15
being base station controllers. The communication network 10 may be a Universal
Mobile Telecommunications System (UMTS) network. In this case, the RAN is a
UMTS Terrestrial Radio Access Network (UTRAN), with the base stations 11- 13 re
spectively being a NodeB and the nodes 14, 15 being a Radio Network Controller
(RNC). The communication network 10 may be a Long Term Evolution (LTE) network.
In this case, the RAN is an evolved UTRAN (eUTRAN), with the base stations
11- 13 respectively being an evolved Node B (eNodeB), and the nodes 14, 15 being a
Mobility Management Entity (MME) and/or Serving Gateway (S-GW) in the core net
work.
The mobile terminal 20 has a wireless interface 2 1 or several wireless interfaces 2 1
to communication with at least one radio access network (RAN). The wireless inter
face^) 2 1 comprises a modem 22. The modem 22 performs the modulation and demodulation,
respectively, required for the respective communication standard used
by the mobile terminal 20. The mobile terminal 20 may be configured for communica
tion with the RAN according to the Radio Resource Control, RRC, protocol. For illus
tration, the mobile terminal 20 may be configured to communicate with the RAN in
accordance with 3GPP specification TS 25.331 . The mobile terminal 20 may be con
figured for radio communication with the RAN in accordance with 3GPP specification
TS 25.331 V 11.5.0 (201 3-03) entitled "3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; Radio Resource Control (RRC); Protocol
specification (Release 11)". Alternatively or additionally, the mobile terminal 20 may
be configured to communicate with the RAN in accordance with 3GPP specification
TS 36.331 . The mobile terminal 20 may be configured for radio communication with
the RAN in accordance with 3GPP specification TS 36.331 V 11.3.0 (201 3-03) enti
tled "3rd Generation Partnership Project; Technical Specification Group Radio Ac
cess Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource
Control (RRC); Protocol specification (Release 11)".
The mobile terminal 20 has different power modes. In at least some of the power
modes, the usage of the modem 22 for processing data transfers or other messages
received by the mobile terminal 20 is limited to reduce the power consumption.
These power modes which provide lower power consumption of the modem are also
referred to as power saving modes herein, or simply as power modes having lower
power consumption than a regular, fully operative power mode.
In several or in all of the power modes, the mobile terminal 20 may be configured to
make transitions between an idle state in which the mobile terminal 20 is in an RRC
disconnected state and an RRC connected state. This distinguishes the power
modes which provide reduced power consumption from conventional discontinuous
reception, DRX, states or from the URA_PCH state, the CELL_PCH state, the
CELL FACH state, and the CELL DCH state as defined in 3GPP specification TS
25.331 . The mobile terminal 20 may have the states defined in 3GPP specification
TS 25.331 V 11.5.0 (201 3-03) entitled "3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; Radio Resource Control (RRC); Protocol
specification (Release 11)", sections 7.1 and 7.2, and may switch between the states
while operating in a selected power mode. The mobile terminal 20 may be in one of
these states to receive signals while operating in one of the various power modes
which provide lower power consumption, but still remains operative to switch be
tween the idle state and the RRC connected state while being in the respective
power mode. By contrast, the mobile terminal 20 is always in the RRC connected
state when operating in the URA_PCH state, the CELL_PCH state, the CELL FACH
state, and the CELL DCH state.
The mobile terminal 20 has a processing device 23 which controls operation of the
mobile terminal 20. The processing device 23 may comprise one microprocessor or
several microprocessors, one microcontroller or several microcontrollers, an applica
tion specific integrated circuit (ASIC) or a combination of such components. The pro
cessing device 23 may perform operations of a logic which determines which one of
the several power modes should be used, as will be described in more detail with
reference to Fig. 2 to Fig. 9 .
The mobile terminal 20 is configured such that it can request that a specific power
mode of the plurality of available power modes shall be used. For illustration, up to
four or up to eight different power modes may be pre-defined. An indicator may be
assigned to each one of the power modes. As used herein, the term "indicator" for a
power mode refers to a unique identifier which may be assigned to the respective
power mode such that one of a plurality of power modes may be uniquely identified
based on the indicator.
The mobile terminal 20 is configured to transmit a power mode change request to the
communication network 10. The power mode change request may include several
purpose bits which contain the unique identifier for a power mode selected by the
mobile terminal 20. The processing device 23 may control the wireless interface 2 1 to
transmit the power mode change request with the indicator for the selected power
mode.
The communication network 10 may transmit a power mode change response to the
mobile terminal 20. The power mode change response may be an acknowledgement
message confirming that the mobile terminal 20 may enter the power mode previ
ously selected by the mobile terminal 20 as being a suitable power mode. This suit
able power mode is defined by the indicator in the power mode change request
transmitted by the mobile terminal 20.
The decision on which power mode is a suitable power mode may be performed in a
wide variety of ways. In one implementation, the processing device 23 selects the
power mode depending on whether the mobile terminal 20 is in a standby mode. The
power mode may be selected depending on whether the mobile terminal 20 has been
in a standby mode for a certain time period. The power mode may be selected de
pending on whether a display 25 of the mobile terminal 20 has been switched off for
a predefined time period. The power mode may be selected depending on an output
signal of a sensor of the mobile terminal 20. For illustration, the mobile terminal 20
may have a motion sensor 26. Based on an output signal of the motion sensor 26
and/or information on whether the display 25 is switched on or off, the processing
device 23 may determine which power mode would be suitable.
The processing device 23 may also execute applications. At least one application or
several of the applications may continue to be executed even when the mobile termi
nal 20 has entered a standby mode, for example. Examples for such applications
include social networks, e-mail services, update clients such as news update centers
or weather forecasts, without being limited thereto. The application(s) would normally
transmit data over the wireless interface 2 1 to the communication network 10 and
would receive data from the communication network 10 . The power modes with lower
power consumption than the regular power mode ensure that the data transfers to
the mobile terminal 20 are reduced by signalling to the communication network that a
specific power mode should be used.
The decision on which power mode is a suitable power mode may also take into a c
count which applications are executed on the mobile terminal 20. For illustration,
when an e-mail application is being executed by the mobile terminal 20, the process
ing device 23 may select a power mode which allows data to be transferred to the
mobile terminal 20 more frequently than if only a news update service or weather
forecast application are executed. The processing device 23 may predict which data
traffic will be required in dependence on the applications which are executed on the
mobile terminal 20.
The different power modes may each have a set of parameters 24 which defines o p
eration in the respective power mode. The power mode parameters 24 may be
stored in the mobile terminal 20. The power mode parameters may define how pa
rameters or functionalities in a physical layer are defined. The power mode parame
ters may define parameters for the physical layer of the air interface between the
mobile terminal 20 and the communication network 10 . Alternatively or additionally,
the power mode parameters may be parameters for layer 2 and/or layer 3 signalling
between the mobile terminal 20 and the communication network 10 .
The specific definition of the various power modes and the respective parameters
may depend on the configuration of the mobile terminal 20. For illustration, for a mo
bile terminal which is a mobile phone, the different power modes may correspond to
definitions of different DRX cycle lengths and/or different paging cycles when the
mobile terminal is in an RRC disconnected state while operating in the respective
mode. For further illustration, the different power modes may correspond to different
output power classes of the mobile terminal 20.
Additionally or alternatively, the selected power mode may add one or more addi
tional DRX cycles. A power mode could for example add a long DRX level, in addi
tion to a standard idle state DRX, to the idle RRC state.
Additionally or alternatively, the selected power mode may define a different protocol
procedure for the mobile terminal accessing the wireless network.
Additionally or alternatively, the selected power mode may define different radio pa
rameters, e.g. one or several different terminal output power classes and/or may limit
the transmission/reception to half duplex operation.
Additionally or alternatively, the selected power mode may define different mobility
management procedures. The selected power mode may limit or remove cell change
possibilities to reduce required measurements to be performed in the mobile termi
nal.
When the mobile terminal 20 switches to the selected power mode in response to
receiving a power mode switch response from the communication network 0, the
modem 22 may be controlled in dependence on the power mode parameters for the
respective power mode. The processing device 23 may retrieve the power mode parameters
from the memory 24.
The mobile terminal 20 may have various configurations. For illustration, the mobile
terminal 20 may be a machine-to-machine (M2M) communication terminal. The mo
bile terminal 20 may communicate with another M2M terminal 29 through the communication
network 10 . The number of defined power modes and/or the specific
power mode parameters may depend on the specific configuration of the mobile terminal
20. This allows one to optimize physical layer behaviour towards different M2M
use cases, smartphones in different modes, non-voice centric devices, or similar.
Fig. 2 is a flow chart of a method 30 according to an embodiment. The method 30
may be performed by the mobile terminal 20.
At 3 1, a logic determines a most suitable power mode for the mobile terminal. A se
lection algorithm may be employed to determine which power mode of a plurality of
power modes is the most suitable power mode. In one implementation, a power
mode with lower power consumption than a regular, fully operative power mode may
be determined if the display 25 is off. Additional or alternative inputs may be used in
the determination, e.g. an output signal of a motion sensor, information on running
applications, etc.
The most suitable power mode may be identified such that it meets an expected fu
ture signalling need for the mobile terminal 20. The future signalling need may be
predicted based on the applications which are executed. Historical data on the s ig
nalling associated with each application may be collected by the mobile terminal 20
and may be used to predict the future signalling need, for example. Alternatively or
additionally, information may be retrieved from the applications which define the s ig
nalling need of each application. In determining the most suitable power mode, pre
vious power mode changes may also be taken into account. For illustration, if the
current power mode has been active for only a short time period so far, penalties
may be imposed on the other power modes in the selection algorithm to introduce
hysteric behaviour which prevents ping-pong behaviour.
At 32, the logic determines whether a change of power mode should be requested. A
change of power mode may be requested if the most suitable power mode deter
mined at 3 1 is different from a current power mode. A change of power mode may be
requested if the same power mode is consistently identified as the most suitable
power mode for a predefined period. If it is determined that no change of power
mode is to be requested, the method returns to step 3 1.
If a change of power mode is to be requested, a power mode change request is
transmitted by the mobile terminal. The power mode change request depends on the
power mode which is identified as the most suitable power mode at step 3 1.
If power mode " 1" is selected because it is the most suitable power mode, at 33 a
power mode change request is transmitted which includes an indicator for the power
mode " 1" . If power mode "2" is selected because it is the most suitable power mode,
at 34 a power mode change request is transmitted which includes an indicator for the
power mode "2". If power mode "M" is selected because it is the most suitable power
mode, at 35 a power mode change request is transmitted which includes an indicator
for the power mode "M".
The respective power mode is entered in response to receiving a power mode
change response which positively acknowledges the power mode change request.
The method may then return to step 3 1.
Fig. 3 shows a signalling between the mobile terminal 20 and the base station 11 of
the communication network.
The mobile terminal 20 transmits a message 4 1 which is a power mode change re
quest. The power mode change request includes an indicator PMID for the selected
power mode. The indicator PMID may be contained in two indicator bits or in three
indicator bits of the message 4 1, for example. Up to four or up to eight different
power modes may be defined thereby.
The base station 11 determines whether the mobile terminal 20 may switch its power
mode to the selected power mode indicated by the indicator PMID in the message
4 1. The determining may include determining whether the data transmission speeds
and/or network load meet target conditions even when the mobile terminal 20 switch
es to the selected power mode indicated by the indicator PMID.
If the base station 11 or another RAN node determines that the mobile terminal 20
may switch its power mode to the selected power mode, it transmits a positive acknowledgement
(ack) message 42 to the mobile terminal 20. The message 42 is a
power mode change response which accepts the power mode switching requested
by the mobile terminal.
At 43, in response to receiving the power mode change response which accepts the
power mode switching, the mobile terminal 20 changes the power mode to the power
mode indicated in the message 4 1. The change may occur at a pre-defined time or
may be triggered by a triggering event. The change may occur selectively in depend
ence on whether the positive acknowledgment message 42 was received.
At 44, the base station 11 and/or another node in the RAN may adjust data transfers
to the mobile terminal 20 in accordance with the indicator for the power mode in
cluded in the power mode change request message 4 1. This may limit signalling to
wards the mobile terminal 20 if a power mode with low power consumption is se
lected. The adjustment may be made at layer 1 of the signalling between the base
station 11 and the mobile terminals 20. The adjustment may be made at layer 2
and/or layer 3 of the signalling between the base station 11 and the mobile terminals
20.
Fig. 4 illustrates the signalling when the base station 11 or another RAN node deter
mines that the mobile terminal 20 may not switch its power mode to the selected
power mode. The base station 11 or another RAN node transmits a negative ac
knowledgement (nack) message 45 to the mobile terminal 20. The message 45 is a
power mode change response which rejects the power mode switching requested by
the mobile terminal.
In response to receiving the power mode change response which rejects the power
mode switching, the mobile terminal 20 does not change its power mode. The mobile
terminal 20 may, however, subsequently transmit a new power mode change re
quest. The base station 11 does not adjust the signalling with the mobile terminal at
layer 1, layer 2 and/or layer 3 because no power mode switching is performed.
In addition to the mobile terminal initiated power mode switching explained above,
the mobile terminal and RAN may also be configured for a RAN-initiated power mode
switching. In this case, the RAN may transmit a power mode change request which
includes an identifier for one power mode of the plurality of power modes. This is illustrated
in Fig. 5 .
The base station 11 or another RAN node transmits a message 46 which is a further
power mode change request. The further power mode change request includes an
indicator for a further power mode selected by the base station 11 or another RAN
node.
The mobile terminal 20 determines whether the power mode switching to the further
power mode can be made. The mobile terminal 20 may determine whether required
data transmission speeds and/or transmission delays could be attained when the
mobile terminal 20 switches to the further power mode indicated by the message 46.
If the mobile terminal 20 accepts the requested power mode switching, it transmits an
acknowledgment message 47. The mobile terminal 20 subsequently switches to the
further power mode at 43.
If the mobile terminal 20 rejects the requested power mode switching, it transmits a
negative acknowledgment message (not shown in Fig. 5).
The plural power modes must not be confused with the RRC disconnected state and
the RRC connected states. The mobile terminal 20 may still switch between the RRC
disconnected state and the RRC connected state while it remains in one and the
same power mode. The power modes may be distinguished in the parameters of the
physical layer of the radio interface which are respectively used, for example.
The signalling explained with reference to Fig. 3, Fig. 4, and Fig. 5 may be performed
during an RRC Connection Establishment procedure or during an RRC Connection
Reconfiguration procedure.
The signalling explained with reference to Fig. 3, Fig. 4, and Fig. 5 may be performed
during an RRC Connection Establishment procedure or during an RRC Connection
Reconfiguration procedure as defined in 3GPP specification TS 25.331 or as defined
in 3GPP specification TS 36.331 . The signalling explained with reference to Fig. 3,
Fig. 4, and Fig. 5 may be performed during an RRC Connection Establishment pro
cedure as defined in 3GPP specification TS 25.331 V 11.5.0 (201 3-03) entitled "3rd
Generation Partnership Project; Technical Specification Group Radio Access Network;
Radio Resource Control (RRC); Protocol specification (Release 11)", section
8.1 .3. Alternatively or additionally, the signalling explained with reference to Fig. 3,
Fig. 4, and Fig. 5 may be performed during an RRC Connection Establishment pro
cedure or during an RRC Connection Reconfiguration procedure as defined in 3GPP
TS 36.331 V 11.3.0 (201 3-03) entitled "3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Ac
cess (E-UTRA); Radio Resource Control (RRC); Protocol specification (Release 11)",
section 5.3.3 or section 5.3.5.
Fig. 6 schematically illustrates various RRC states which the mobile terminal may
have. In an idle state 50, the mobile terminal 20 is RRC disconnected. In an RRC
connected state 5 1, the mobile terminal 20 is RRC connected. The RRC connected
state may have various sub-states. The sub-states may include an active state w ith
out DRX 52, a short DRX cycle state 53, and a long DRX cycle state 54. Transitions
55-57 between the different RRC states may be triggered when an inactivity timer
expires.
In a power mode selected by the mobile terminal 20, the mobile terminal 20 may still
be operative to make transitions between the RRC disconnected state 50 and the
RRC connected state 5 1, including sub-states of the RRC connected state 5 1 .
Fig. 7 is a functional block representation of a mobile terminal according to an embodiment.
A power mode selection logic 6 1 may determine which power mode of a plurality of
power modes should be used. The power mode selection logic 6 1 may select a pow
er mode in dependence on a signal 65 indicating whether the display is switched on
or off. Alternatively or additionally, the power mode selection logic 62 may select a
power mode in dependence on a signal 66 which is indicative of a motion of the mo
bile terminal. The signal 66 may be an output signal of a motion sensor. Alternative
or additional signals may be evaluated to determine which power mode would be
most suitable.
The power mode selection logic 6 1 may control a modem 62 to transmit a power
mode change request with an indicator for a selected power mode. The power mode
selection logic 6 1 may determine whether a power mode change response received
from the communication network is an ack-message or a nack-message. Depending
on the response, the power mode selection logic 6 1 may control the modem 62 to
switch the mobile terminal to the selected power mode. Power mode switching may
comprise adapting the layer 1, layer 2, and/or layer 3 signalling between the mobile
terminal and the communication network.
The power mode selection logic 6 1 may also selectively control a firewall 64. The
firewall 64 is operative to restrict or prevent an application or several applications 63
running on the mobile terminal from transmitting data to the communication network.
The firewall 64 limits modem usage by the application(s) for outgoing data transfers.
Fig. 8 shows a schematic block diagram representation of a RAN node 70 according
to an embodiment. The RAN node 70 may be an eNodeB, for example. The RAN
node 70 has a wireless interface 7 1 to receive a power mode change request from
the mobile terminal 20. The RAN node 70 has a controller 72 configured to retrieve
an indicator for a power mode from the received power mode change request. The
controller 72 may be configured to determine whether power mode switching of the
mobile terminal 20 to the selected power mode may be accepted. If the power mode
switching can be accepted, the controller 72 controls the wireless interface 7 1 to o ut
put a power mode change response to acknowledge the requested power mode
switching.
The controller 72 is configured to control data transmission to and from the mobile
terminal 20 in dependence on the selected power mode identified by the indicator in
the received power mode change request. Power mode parameters 73 may be
stored in the RAN node 70 for each one of the plurality of power modes which the
mobile terminal may select. The power mode parameters 73 for different power
modes may include different parameters for layer 1 signalling between the mobile
terminal and the RAN. The power mode parameters 73 for different power modes
may include different parameters for layer 2 signalling between the mobile terminal
and the RAN. The power mode parameters 73 for different power modes may include
different parameters for layer 3 signalling between the mobile terminal and the RAN.
Fig. 9 is a flow chart of a method 80 according to an embodiment. The method 80
may be performed by the mobile terminal 20. The method 80 illustrates one exem
plary use case for mobile terminal initiated power mode switching. In the method 80,
a power mode with low power consumption is selected when the mobile terminal 20
is not in use, while some applications continue to be executed on the mobile terminal
20.
At 8 1, user inactivity is detected. User inactivity may be detected by determining
whether the input actions were performed on an input interface or whether there is
ongoing voice or data communication.
At 82, the display is switched off after a delay time.
At 83, it is determined whether the display has been switched off for a predetermined
period. If the display has not been switched off for a predetermined period, the moni
toring may be continued. When user activity is detected, the display is switched on
again. When it is detected that the display has been switched off for a predetermined
period, the method proceeds to 84.
At 84, outgoing data traffic transmitted from applications to the communication net
work is limited. A firewall between the application(s) and a modem may be activated
to reduce modem usage of the application(s) for outgoing data traffic.
At 85, a power mode change request is transmitted. The power mode change re
quest comprises an indicator for a selected power mode. The mobile terminal may
select the power mode based on the signalling needs anticipated for a state in which
the display is switched off and the mobile terminal is not being used by the user.
At 86, it is determined whether a power mode change response is received from the
communication network to indicate that the change to the selected power mode is
approved. If the communication network rejects the power mode switching, the
method may terminate or may return to step 85 after a delay.
At 87, in response to receiving a power mode change response which accepts the
requested power mode switching, the mobile terminal enters the selected power
mode.
Various effects are attained by the devices and methods according to embodiments.
For illustration, the mobile terminal initiated signalling to request that a specific power
mode may be used may efficiently control the incoming data traffic received by the
mobile terminal from the network. The mobile terminal can still switch between RRC
connected and RRC disconnected states in the selected power mode, while the pa
rameters settings for layer 1, layer 2, and/or layer 3 signalling between the mobile
terminal and the RAN may depend on the power mode.
While exemplary embodiments have been described with reference to the drawings,
modifications may be implemented in other embodiments. For illustration, the UE
may be a mobile phone, a M2M terminal, or another mobile terminal. Further, while
exemplary network technologies have been described, embodiments of the invention
may be used in combination with other network technologies.
The operation of the various functional units may be implemented by hardware, by
software, or a combination thereof. For illustration, the functions of the logic which
selects a power mode may be performed by a microprocessor or microcontroller
which executes instructions programmed in a non-volatile memory.

C LA IM S
1. A mobile ternninal, comprising:
a modem (22; 62) for communication with a wireless network ( 10), and
a logic (23; 6 1) configured to
- select a power mode from a plurality of power modes,
- control the modem (22; 62) to transmit a power mode change request (41 )
which includes an indicator for the selected power mode, and
- in response to receiving a power mode change response (42), control the
mobile terminal (20, 29) to switch to the selected power mode.
2 . The mobile terminal of claim 1,
wherein the logic (23; 6 1) is configured to select the power mode in dependence on
applications (63) executed by the mobile terminal (20, 29) to reduce data transfers to
the mobile terminal (20, 29) while the applications (63) are executed by the mobile
terminal (20, 29).
3 . The mobile terminal of claim 1 or claim 2,
wherein the mobile terminal (20, 29) is configured to switch between different Radio
Resource Control, RRC, states (50-54) while operating in the selected power mode.
4 . The mobile terminal of claim 3,
wherein the selected power mode and at least one other power mode of the plurality
of power modes have different parameter settings for physical layer signalling be
tween the mobile terminal (20, 29) and the communication network ( 10).
5 . The mobile terminal of claim 3 or claim 4,
wherein the selected power mode and at least one other power mode of the plurality
of power modes have different discontinuous reception, DRX, parameter settings,
wherein the different DRX parameter settings comprise at least one of:
- different DRX cycle lengths,
- different inactivity timer values, and/or
- different paging cycles.
6 . The mobile terminal of any one of claims 3 to 5,
wherein the mobile terminal (20, 29) is configured to switch between an idle state and
an RRC connected state while operating in the selected power mode.
7 . The mobile terminal of any one of claims 3 to 6,
wherein the mobile terminal (20, 29) is configured to transmit the power mode
change request (41 ) in an RRC Connection Establishment procedure or in an RRC
Connection Reconfiguration procedure.
8 . The mobile terminal of any one of the preceding claims,
further comprising:
a display (25),
wherein the logic (23; 6 1) is configured to select the power mode in depend
ence on whether the display (25) is switched off.
9 . The mobile terminal of claim 8, further comprising:
at least one sensor (26),
wherein the logic (23; 6 1) is configured select the power mode in dependence
on whether the display (25) is switched off and in dependence on an output signal
(66) of the at least one sensor (26).
10 . The mobile terminal of claim 8 or claim 9,
wherein the logic (23; 6 1) is configured to prevent an application (63) from
causing a data transmission via the modem (22; 62) when the display (25) is
switched off.
11. The mobile terminal of any one of the preceding claims,
wherein the power mode change request (41 ) comprises a plurality of indicator bits
which include the indicator for the selected power mode.
12 . The mobile terminal of any one of the preceding claims,
wherein the logic (23; 6 1) is configured to
- identify a further power mode in dependence on a further power mode identi
fier included in a further power mode change request (46) received by the mo
bile terminal (20, 29),
- in response to receiving the further power mode change request (46), control
the modem (22; 62) to transmit a further power mode change response (42),
and
- in response to receiving the further power mode change request (46), control
the mobile terminal (20, 29) to switch to the further power mode.
13 . A communication system, comprising:
the mobile terminal (20, 29) of any one of the preceding claims; and
a radio access network ( 10) configured to
- receive the power mode change request (41 ) from the mobile terminal (20,
29),
- identify the selected power mode based on the indicator included in the
power mode change request (41 ) ,
- transmit a power mode change response (42) to the mobile terminal (20,
29), and
- control data transfers to the mobile terminal (20, 29) based on the selected
power mode.
14. A method of performing a transition between power modes of a mobile termi
nal (20, 29), the method comprising:
- selecting, by the mobile terminal (20, 29), a power mode from a plurality of
power modes,
- transmitting, by the mobile terminal (20, 29), a power mode change request
(41 ) over a wireless interface (21 ) , the power mode change request (41 )
including an indicator for the selected power mode,
- in response to receiving a power mode change response (42), switching to
the selected power mode by the mobile terminal (20, 29).
15 . The method of claim 14,
performed by the mobile terminal (20, 29) of any one of claims 1 to 12 .