Enhanced network and UE power saving

Abstract

According to an aspect, there is provided an apparatus configured to perform the following The apparatus receives, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages. Each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance. The received plurality of scheduling control messages correspond to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation. The apparatus receives, from the access node after or during said gradual decrease, a message indicating a deactivation of the cell coverage for the at least one cell. Based on the reception of the message, the apparatus transitions from the primary data communication mode to a power saving mode having reduced data communication capability.

Description

ENHANCED NETWORK AND UE POWER SAVINGTECHNICAL FIELD

[0001] Various example embodiments relate to wireless communications.BACKGROUND

[0002] In order to enable power savings for a terminal device in an idle (or IDLE) state, use of a dedicated (low-power) wake-up signal radio receiver in the terminal device, in addition to a main or primary radio receiver, has been proposed. Use of such a dedicated (low-power) wake-up signal radio receiver for reception of downlink wake-up signals allows a terminal device to be kept asleep, with the main or primary radio receiver inactive, till a (low-power) downlink wake-up signal (WUS or LP-WUS) is received. This serves to reduce the energy consumption while increasing the battery life of the terminal device. However, the operation of the terminal device employing such a power saving mode as well as the associated access node may still be further optimized for enabling further power saving.SUMMARY

[0003] According to an aspect, there is provided the subject matter of the independent claims. Embodiments are defined in the dependent claims.

[0004] According to a first aspect, there is provided an apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:receiving, from an access node, downlink wake-up signals periodically with a first period;detecting a need for data communication;based on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of cell coverage at the access node; andfollowing the transmitting, receiving, from the access node, downlink wake-up signals periodically with a second period different from the first period.

[0005] According to a first embodiment of the first aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, from the access node, a message defining a change from the first period to the second period.

[0006] According to a second embodiment of the first aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:operating, while receiving the downlink wake-up signals, in a power saving mode having reduced data communication capability compared to a primary data communication mode of the apparatus.

[0007] According to a third embodiment of the first aspect, further defining the second embodiment,the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of the uplink wake-up signal, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of the downlink wake-up signals,the primary radio transmitter and receiver being disabled and the dedicated wakeup signal radio transmitter and receiver being enabled in the power saving mode, or wherein the apparatus comprises a primary radio transmitter usable for transmission of the uplink wake-up signal, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of the downlink wake-up signals,the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of uplink wake-up signals in the power saving mode.

[0008] According to a fourth embodiment of the first aspect, further defining the second or third embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, from the access node, a cell coverage activation downlink wake-up signal indicating activation of the cell coverage at the access node; andbased on the reception of the cell coverage activation downlink wake-up signal, transitioning from the power saving mode to the primary data communication mode.

[0009] According to a fifth embodiment of the first aspect, further defining the fourth embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, from the access node, a message indicating deactivation of the cell coverage at the access node; andbased on the reception of the message, transitioning from the primary data communication mode to the power saving mode.

[0010] According to a second aspect, there is provided an apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:broadcasting downlink wake-up signals periodically with a first period; receiving, in response to at least one of said downlink wake-up signals, zero or more uplink wake-up signals from zero or more terminal devices;determining a second period for the broadcasting of the downlink wake-up signals based on the received zero or more uplink wake-up signals; andbroadcasting, based on said determining, the downlink wake-up signals periodically with the second period.

[0011] According to a first embodiment of the second aspect, the determining of the second period is based on:the number of the received zero or more uplink wake-up signals; and / or the number of consecutive broadcasts of the downlink wake-up signals for which at least one uplink wake-up signal was received as a response.

[0012] According to a second embodiment of the second aspect, further defining the first embodiment, the determining of the second period comprises:determining the second period to be smaller than the first period based on the number of the zero or more uplink wake-up signals received in response to said downlink wakeup signals being larger than or equal to a first pre-defined threshold; ordetermining the second period to be smaller than the first period based on the number of the consecutive broadcasts of the downlink wake-up signal for which at least oneuplink wake-up signal was received as a response being larger than or equal to a second predefined threshold.

[0013] According to a third embodiment of the second aspect, further defining the first or second embodiment, the determining of the second period comprises:determining the second period to be larger than the first period based on the number of the zero or more uplink wake-up signals received in response to said downlink wakeup signals being smaller than or equal to a third pre-defined threshold; ordetermining the second period to be larger than the first period based on the number of consecutive broadcasts of the downlink wake-up signals for which at least one uplink wake-up signal was received as a response being smaller than or equal to a fourth predefined threshold.

[0014] According to a fourth embodiment of the second aspect, the apparatus comprises a primary radio transmitter for enabling cell coverage in downlink for at least one cell, a dedicated wake-up signal radio transmitter for broadcasting downlink wake-up signals, a primary radio receiver for enabling cell coverage in uplink for at least one cell and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals,wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:operating the apparatus in a power saving mode where the dedicated wake-up signal radio transmitter and receiver are enabled and the primary radio transmitter and the primary radio receiver are disabled.

[0015] According to a fifth embodiment of the second aspect, further defining the fourth embodiment, the apparatus is configured such that power consumption of the dedicated wakeup signal radio transmitter for periodic broadcasting of the downlink wake-up signals is lower than a power consumption of the primary radio transmitter for periodic broadcasting of synchronization signal blocks.

[0016] According to a sixth embodiment of the second aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, from one or more terminal devices within a pre-defined time window, one or more uplink wake-up signals for requesting the activation of the cell coverage; andbased on the number of the one or more uplink wake-up signals received within the pre-defined time window exceeding a pre-defined activation threshold, triggering activation of cell coverage for at least one cell served by the apparatus, wherein the pre-defined activation threshold has an integer value larger than or equal to one.

[0017] According to a seventh embodiment of the second aspect, further defining the sixth embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:broadcasting a cell coverage activation downlink wake-up signal indicating the activation of the cell coverage.

[0018] According to an eighth embodiment of the second aspect, further defining the sixth or seventh embodiment, the activating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is increased compared to a previous step.

[0019] According to a ninth embodiment of the second aspect, further defining the sixth, seventh or eighth embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:detecting a need for deactivation of the cell coverage;based on the detection of the need for the deactivation of the cell coverage, transmitting, to at least one terminal device, a message indicating deactivation of the cell coverage and deactivating the cell coverage.

[0020] According to a tenth embodiment of the second aspect, further defining the ninth embodiment,the apparatus comprises a primary radio transmitter for enabling cell coverage in downlink for at least one cell, a dedicated wake-up signal radio transmitter for broadcasting downlink wake-up signals, a primary radio receiver for enabling cell coverage in uplink for at least one cell and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, and the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:operating the apparatus in a power saving mode where the dedicated wake-up signal radio transmitter and receiver are enabled and the primary radio transmitter and the primary radio receiver are disabled,wherein the activation of the cell coverage comprises transitioning from the power saving mode to a primary data communication mode where at least the primary radio transmitter and receiver are enabled,wherein the deactivation of the cell coverage comprises transitioning from the primary data communication mode to the power saving mode.

[0021] According to a third aspect, there is provided a method comprising:receiving, from an access node, downlink wake-up signals periodically with a first period;detecting a need for data communication;based on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of cell coverage at the access node; andfollowing the transmitting, receiving, from the access node, downlink wake-up signals periodically with a second period different from the first period.

[0022] According to a fourth aspect, there is provided a method comprising:broadcasting downlink wake-up signals periodically with a first period; receiving, in response to at least one of said downlink wake-up signals, zero or more uplink wake-up signals from zero or more terminal devices;determining a second period for the broadcasting of the downlink wake-up signals based on the received zero or more uplink wake-up signals; andbroadcasting, based on said determining, the downlink wake-up signals periodically with the second period.

[0023] According to a fifth aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:receiving, from an access node, downlink wake-up signals periodically with a first period;detecting a need for data communication;based on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of cell coverage at the access node; andfollowing the transmitting, receiving, from the access node, downlink wake-up signals periodically with a second period different from the first period.

[0024] According to a sixth aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:broadcasting downlink wake-up signals periodically with a first period; receiving, in response to at least one of said downlink wake-up signals, zero or more uplink wake-up signals from zero or more terminal devices;determining a second period for the broadcasting of the downlink wake-up signals based on the received zero or more uplink wake-up signals; andbroadcasting, based on said determining, the downlink wake-up signals periodically with the second period.

[0025] According to a seventh aspect, there is provided comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell, andbased on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

[0026] According to a first embodiment of the seventh aspect, the message is a paging message.

[0027] According to a second embodiment of the seventh aspect, the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter fortransmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orthe apparatus comprises a primary radio transmitter usable for transmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of uplink wake-up signals during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

[0028] According to a third embodiment of the seventh aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, while operating in the power saving mode, a cell coverage activation downlink wake-up signal indicating activation of the cell coverage for said at least one cell of the access node from the access node; andbased on the cell coverage activation downlink wake-up signal, transitioning from the power saving mode to the primary data communication mode.

[0029] According to a fourth embodiment of the seventh aspect, further defining the third embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform, following the transitioning from the power saving mode to the primary data communication mode:receiving, from the access node, a second plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more timefrequency resources for a next transmission time instance, the received second plurality of scheduling control messages corresponding to scheduling performed during a gradual increase of bandwidth at the at least one cell in two or more steps following the activation of the cell coverage.

[0030] According to a sixth embodiment of the seventh aspect, further defining the fourth or fifth embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform, before the reception of the cell coverage activation downlink wake-up signal:detecting, while operating in the power saving mode, a need for data communication; andbased at least on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of the cell coverage at the access node.

[0031] According to an eighth aspect, there is provided an apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:detecting a need for deactivation of cell coverage for at least one cell served by the apparatus;based on the detection, triggering deactivation of the cell coverage, wherein the deactivating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step; andafter or during the deactivation of the cell coverage, transmitting, to one or more terminal devices, a message indicating the deactivation of the cell coverage.

[0032] According to a first embodiment of the eighth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:during the gradual deactivation of the cell coverage, transmitting, to the one or more terminal devices in said at least one cell, a plurality of scheduling control messages so as to schedule time-frequency resources employing the gradually decreasing bandwidth of the least one cell.

[0033] According to a second embodiment of the eighth aspect, the message is a paging message.

[0034] According to a third embodiment of the eighth aspect, the gradual deactivating of the cell coverage for the at least one cell is based on the number and / or capacity requirements of the one or more terminal devices in said at least one cell.

[0035] According to a fourth embodiment of the eighth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform the detection, the triggering of the deactivation and the transmitting of the message while operating in a primary data communication mode, and to perform:after the deactivation of the cell coverage, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

[0036] According to a fifth embodiment of the eighth aspect, further defining the fourth embodiment,the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orthe apparatus comprises a primary radio transmitter usable for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of downlink wake-up signals during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

[0037] According to a sixth embodiment of the eighth aspect, further defining the fourth or fifth embodiment, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:detecting, while operating in the power saving mode, a need for activation of the cell coverage; andbased on the detecting of the need for the activation of the cell coverage, broadcasting a cell coverage activation downlink wake-up signal indicating activation of the cell coverage for said at least one cell and activating the cell coverage, wherein the activating of the cell coverage comprises transitioning from the power saving mode to the primary data communication mode.

[0038] According to a seventh embodiment of the eighth aspect, further defining the sixth embodiment, the detecting the need for the activation of the cell coverage comprises:receiving, from one or more terminal devices within a pre-defined time window, one or more uplink wake-up signals for requesting the activation of the cell coverage; and determining that the number of the one or more uplink wake-up signals received within the pre-defined time window exceeds a first pre-defined activation threshold.

[0039] According to an eighth embodiment of the eighth aspect, further defining the seventh embodiment, the detecting the need for the activation of cell coverage comprises:receiving, from a core network, one or more requests for the activation of the cell coverage; anddetermining that the number of the one or more requests exceeds a second predefined activation threshold; ordetermining that a pre-defined amount of time has passed since reception of an initial one of the one or more requests.

[0040] According to a ninth embodiment of the eighth aspect, further defining the sixth, seventh or eighth embodiment, the activating of the cell coverage for the at least one cell is performed gradually in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial reduced value and, at each subsequent step, the bandwidth at the at least one cell is increased compared to a previous step.

[0041] According to a ninth aspect, there is provided a method comprising:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell, andbased on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

[0042] According to a tenth aspect, there is provided a method comprising:detecting a need for deactivation of cell coverage for at least one cell served by the apparatus;based on the detection, triggering deactivation of the cell coverage, wherein the deactivating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step; andafter or during the deactivation of the cell coverage, transmitting, to one or more terminal devices, a message indicating the deactivation of the cell coverage.

[0043] According to an eleventh aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell, andbased on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

[0044] According to a twelfth aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:detecting a need for deactivation of cell coverage for at least one cell served by the apparatus;based on the detection, triggering deactivation of the cell coverage, wherein the deactivating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step; andafter or during the deactivation of the cell coverage, transmitting, to one or more terminal devices, a message indicating the deactivation of the cell coverage.

[0045] According to a thirteenth aspect, there is provided an apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:receiving, while operating in a power saving mode in a cell that has deactivated cell coverage, downlink wake-up signals periodically;detecting, in the power saving mode, an event requiring high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority greater than a threshold; andtransmitting, to an access node, a high-priority uplink wake-up signal for immediate activation of cell coverage at the access node, wherein the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals.

[0046] According to a first embodiment of the thirteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform the transmitting of the high-priority uplink signal immediately following the detection of the event.

[0047] According to a second embodiment of the thirteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:following the transmitting of the high-priority uplink wake-up signal, transitioning from the power saving mode to a primary data communication mode, wherein the power saving mode has reduced communication capability compared to the primary data communication mode; andwhile operating in the primary data communication mode, transmitting uplink data associated with the event to the access node and / or receiving downlink data associated with the event from the access node.

[0048] According to a third embodiment of the thirteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, from the access node, a cell coverage activation downlink wake-up signal indicating activation of the cell coverage at the access node,wherein the transitioning from the power saving mode to the primary data communication mode is based on the reception of the cell coverage activation downlink wakeup signal.

[0049] According to a fourth embodiment of the thirteenth aspect,the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orthe apparatus comprises a primary radio transmitter usable for transmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of uplink wake-up signals during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

[0050] According to a fifth embodiment of the thirteenth aspect, the event is a high-priority call, preferably an emergency call or a multimedia priority service call, or the event is a high-priority service.

[0051] According to a sixth embodiment of the thirteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, while operating in the primary data communication mode, a configuration of the high-priority uplink wake-up signal as radio resource control signaling or as broadcasted system information.

[0052] According to a fourteenth aspect, there is provided an apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:receiving, while operating in a power saving mode, a high-priority uplink wakeup signal indicating a need for high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority higher than a threshold, and the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals; andin response to the reception of the high-priority uplink wake-up signal, triggering activation of cell coverage for at least one cell served by the apparatus.

[0053] According to a first embodiment of the fourteenth aspect, the triggering activation of cell coverage is performed immediately following the reception of the high-priority uplink wake-up signal.

[0054] According to a second embodiment of the fourteenth aspect, the triggering of the activation of the cell coverage comprises:transitioning from the power saving mode to the primary data communication mode, wherein the power saving mode has reduced communication capability compared to the primary data communication mode,wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:while operating in the primary data communication mode, receiving high-priority uplink data from the terminal device and / or transmitting high-priority downlink data to the terminal device

[0055] According to a third embodiment of the fourteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:transmitting, to the terminal device, a cell coverage activation downlink wake-up signal indicating activation of the cell coverage at the access node.

[0056] According to a fourth embodiment of the fourteenth aspect,the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orthe apparatus comprises a primary radio transmitter usable for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of downlink wake-up signals during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

[0057] According to a fifth embodiment of the fourteenth aspect, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:transmitting, while operating in a primary data communication mode, a configuration of the high-priority uplink wake-up signal as radio resource control signaling to the terminal device, wherein the power saving mode has reduced communication capability compared to the primary data communication mode; and / orbroadcasting, while operating in the primary data communication mode, system information comprising a configuration of the high-priority uplink wake-up signal.

[0058] According to a fifteenth aspect, there is provided a method comprising: receiving, while operating in a power saving mode in a cell that has deactivated cell coverage, downlink wake-up signals periodically;detecting, in the power saving mode, an event requiring high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority greater than a threshold; andtransmitting, to an access node, a high-priority uplink wake-up signal for immediate activation of cell coverage at the access node, wherein the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals.

[0059] According to a sixteenth aspect, there is provided a method comprising:receiving, while operating in a power saving mode, a high-priority uplink wakeup signal indicating a need for high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority higher than a threshold, and the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals; andin response to the reception of the high-priority uplink wake-up signal, triggering activation of cell coverage for at least one cell.

[0060] According to a seventeenth aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:receiving, while operating in a power saving mode in a cell that has deactivated cell coverage, downlink wake-up signals periodically;detecting, in the power saving mode, an event requiring high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority greater than a threshold; andtransmitting, to an access node, a high-priority uplink wake-up signal for immediate activation of cell coverage at the access node, wherein the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals.

[0061] According to an eighteenth aspect, there is provided a computer program or a non-transitory computer readable medium comprising instructions stored thereon for performing at least the following:receiving, while operating in a power saving mode, a high-priority uplink wakeup signal indicating a need for high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority higher than a threshold, and the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals; andin response to the reception of the high-priority uplink wake-up signal, triggering activation of cell coverage for at least one cell.

[0062] One or more examples of implementations are set forth in more detail in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0063] FIG. 1 illustrates a system to which some embodiments may be applied;

[0064] FIG. 2 illustrates signaling between an access node and a terminal device for enabling adjustment of periodicity of downlink wake-up signal broadcasting according to some embodiments;

[0065] FIG. 3 illustrates signaling between an access node and a terminal device for enabling power-efficient terminal-device-initiated activation of cell coverage according to some embodiments;

[0066] FIG. 4 illustrates signaling between an access node and a terminal device for enabling power-efficient deactivation of cell coverage according to some embodiments;

[0067] FIG. 5 illustrates signaling between an access node, a terminal device and a core network for enabling power-efficient network-initiated activation of cell coverage according to some embodiments;

[0068] FIG. 6 illustrates signaling between an access node and a terminal device for enabling immediate activation of cell coverage according to some embodiments; and

[0069] FIG. 7 illustrates signaling for configuring uplink wake-up signal transmission functionalities according to an embodiment; and

[0070] FIG. 8 illustrates an apparatus according to some embodiments.DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0071] The following embodiments are only presented as examples. Although the specification may refer to “an”, “one”, or “some” embodiment s) and / or example(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment s) or example(s), or that a particular feature only applies to a single embodiment and / or example. Single features of different embodiments and / or examples may also be combined to provide other embodiments and / or examples.

[0072] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0073] As used herein, the term “periodicity” refers to the rate at which a repeating event occurs. The periodicity may be measured as the number of cycles per unit time. A period is an inverse of periodicity. Thus, a large period corresponds to a small periodicity and vice versa. The periodicity may be equally called a frequency though, in the following, the term “frequency” is used only for referring to frequencies of electromagnetic waves or signals while the term “periodicity” and “period” are used for referring to periodic transmissions of those electromagnetic waves or signals.

[0074] In Figures to be discussed below, dashed lines are used for depicting optional features. However, it should also be noted that use of solid lines should not be understood to mean that the associated features are necessarily essential in a given embodiment.

[0075] In the following, different exemplifying embodiments will be described using, as an example of an access architecture to which the embodiments may be applied, a radio access architecture based on long term evolution advanced (LTE Advanced, LTE-A), new radio (NR, 5G) or 6G, without restricting the embodiments to such an architecture, however. It is obvious for a person skilled in the art that the embodiments may also be applied to other kinds ofcommunications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems are the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, the same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide interoperability for microwave access (WiMAX), open radio access network (O-RAN) or any combination thereof.

[0076] FIG. 1 depicts examples of simplified system architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in FIG. 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in FIG. 1.

[0077] The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

[0078] The example of FIG. 1 shows a part of an exemplifying radio access network.

[0079] A communications system comprises one or more access nodes 104 (comprising, e.g., eNodeB(s) and / or gNodeB(s)) for serving terminal devices 100, 102. The access node is a computing device configured to control the radio resources of communication system it is coupled to. The access node 104 may also be referred to as a NodeB (e.g., an eNodeB, a gNodeB or an NR NodeB), a base station (BS), an access point (AP), a network device, a network node. The access node 104includes or is coupled to transceivers. From the transceivers of the access node 104, a connection is provided to an antenna unit that establishes bidirectional radio links to terminal devices 100, 102. The antenna unit may comprise a plurality of antennas or antenna elements. The access node 104 may provide one or more cells.

[0080] In the case of multiple network nodes (e.g., multiple access nodes 103, 106) in the communication network, the network nodes may be connected to each other via an interface. For example, LTE specifications call such an interface as X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called Xn interface.

[0081] The access node(s) 104 are further connected to a core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), packet data networkgateway (P-GW), for providing connectivity of user devices (UEs) to external packet data networks, or mobile management entity (MME), etc. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise e.g. a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise, e.g., an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example.

[0082] As mentioned above, the one or more access nodes 104 serve terminal devices 100, 102. A terminal device (also called a user device, UE, user equipment, user terminal, etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a terminal device may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station. The user equipment may comprise a mobile equipment and at least one universal integrated circuit card (UICC).

[0083] In some embodiments, at least some of the access nodes 104 may comprise a primary radio transmitter, a primary radio receiver, a (dedicated) wake-up signal radio transmitter for transmitting downlink wake-up signals and a (dedicated) wake-up signal radio receiver for receiving uplink wake-up signals. In other words, separate transmitter and receiver may be provided for carrying out the communication relating to wake-up signals. In other embodiments, one or both of the (dedicated) wake-up signal radio transmitter and receiver may be omitted. In such cases, the transmission and / or reception of downlink and / or uplink wakeup signals may be carried out using the primary radio transmitter and / or receiver, respectively.

[0084] A terminal device 100, 102 typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identity (or identification) module (SIM) or UICC, including, but not limited to, the followingtypes of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and / or touch screen computer, tablet, game console, notebook, extended reality (XR) device, multimedia device or a wearable device. Examples of wearable devices comprise a smartwatch, a fitness tracker, smart glasses, smart clothing, a wearable health devices and a smart ring. Here, the SIM may be a physical SIM which may be removable by a user or an embedded SIM (eSIM) embedded directly into the terminal device 100, 102 (and thus not being removable by a user). It should be appreciated that a terminal device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A terminal device may also be an Internet of Things (loT) device, that is, a device having capability to operate in loT network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction. Thus, the terminal devices may not enable direct user interaction or may enable only limited user interaction (e.g., during setup). The terminal device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities. Each terminal device 100, 102 may comprise multiple antennas comprising, e.g., a plurality of antennas for cellular communication, one or more Wi-Fi antennas and / or one or more Bluetooth antennas.

[0085] In some embodiments, at least some of the terminal devices 100, 102 may comprise a primary radio transmitter, a primary radio receiver, a (dedicated) wake-up signal radio transmitter for transmitting uplink wake-up signals and a (dedicated) wake-up signal radio receiver for receiving downlink wake-up signals. In other words, separate transmitter and receiver may be provided for carrying out the communication relating to wake-up signals. In other embodiments, one or both of the (dedicated) wake-up signal radio transmitter and receiver may be omitted. In such cases, the transmission and / or reception of uplink and / or downlink wake-up signals may be carried out using the primary radio transmitter and / or receiver, respectively.

[0086] The communication system of FIG. 1 is also able to communicate with other networks, such as a public switched telephone network or the Internet 112, or utilize services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1 by “cloud” 114). The communication system may alsocomprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

[0087] The RAN may employ, in some embodiments, a distributed access node architecture. Thus, the RAN may comprise, in some embodiments, at least one distributed access node comprising a centralized (or central) unit (CU) 108, one or more distributed units 104 communicatively connected to the centralized unit 108 and one or more (remote) radio heads or units (RRHs, RUs or RRUs) 116, 118, each of which is communicatively connected to at least one of the one or more distributed units (DUs) 104. The one or more radio units 116, 118 and the distributed unit 104 may be specifically connected by a front-haul interface.

[0088] In other embodiments, the RAN may employ a non-distributed access node architecture. In such embodiments, elements 116, 118 may be omitted, and the element 104 may correspond to the non-distributed access node (or access point, AP).

[0089] The (distributed or non-distributed) access node may provide the terminal device 100, 102 (one or more UEs) with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node to the UE 100, 102 and uplink (UL) communication from the UE 100, 102 to the access node. Examples of uplink channels comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network. Examples of downlink channels comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the user equipment.

[0090] For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” (e / g)NodeBs has been introduced. Typically, a network which is able to use “plug-and-play” (e / g)Node Bs, includes, in addition to Home (e / g)NodeBs (H(e / g)nodeBs), a home node B gateway, or HNB-GW (not shown in FIG. 1). A HNB Gateway (HNB-GW), which is typically installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network.

[0091] 5G (and 6G) systems may also utilize satellite communication to enhance or complement the coverage of 5G service, for example by providing backhauling. Exemplary use cases are providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for criticalcommunications, and future railway / maritime / aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay node 104 or by a gNB located on-ground or in a satellite.

[0092] It is obvious for a person skilled in the art that the depicted system is only an example of a part of a radio access system and in practice, the system may comprise a plurality of (e / g)NodeBs (i.e., a plurality of network nodes or elements), the terminal device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (e / g)NodeBs or may be a Home(e / g)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e / g)NodeBs of FIG. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. Typically, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e / g)NodeBs are required to provide such a network structure.

[0093] In order to enable power savings for a terminal device in an idle (or IDLE) state, use of a dedicated (low-power) wake-up signal radio receiver in the terminal device (such as one of the terminal devices 100, 102 of FIG. 1), in addition to a main or primary radio receiver, has been proposed. Use of such a dedicated (low-power) wake-up signal radio receiver allows a terminal device to be kept asleep (with the main or primary radio receiver inactive) till a (low-power) wake-up signal (WUS or LP-WUS) is received. The main or primary radio receiver of the terminal device may, thus, be prevented from waking up periodically according to a discontinuous reception (DRX) cycle. Therefore, this technique serves to keep the terminal device in a low-power idle or inactive state (equally called a power saving mode) for most of the time helping to reduce the energy consumption while increasing the battery life of the terminal device. Devices which need to operate in an energy-efficient manner such as loT devices and wearable devices would be most benefitted by use of this technology though use of this technology is not limited to such devices.

[0094] However, there is still room for improvement when it comes power-efficiency of communication systems employing the aforementioned wake-up radio signal radio receiver (at least) at the terminal device. At least some of the embodiments to be discussed below seek to enable further power saving at the terminal device and especially at the associated access node. For example, some of the embodiments considers the questions of when should an access node be woken up (i.e., exit a power saving mode) so as to both serve terminal devices at a sufficient level and minimize power consumption and of how to flexibly control and maximize the duration of power savings at the access node based on the actual requirements at the network and terminal device sides.

[0095] FIG. 2 illustrates signaling between an access node and a terminal device (i.e., UE) for enabling adjustment of periodicity of downlink wake-up signal broadcasting according to embodiments so as to optimize power consumption at the terminal device and the access node. The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a part thereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 2 shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at least some of them) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node.

[0096] At least in some embodiments, the terminal device and / or the access node may be assumed to be operating during the process of FIG. 2 in a power saving mode. The power saving mode may be associated with reduced data communication capability (and, consequently, reduced power consumption) compared to a primary data communication mode of the same device (equally called a main data communication mode). For example, transmission / reception of synchronization signal blocks (SSBs) may be disabled when operating in the power saving mode but enabled when operating in the primary data communication mode. In some embodiments, any communication mode where transmission and reception is not limited to the wake-up signals transmission and reception may be considered a primary data communication mode. In the power saving mode, only transmission and reception of wake-up signals may be enabled (that is, transmission of normal broadcast signals such as synchronization signal blocks may be disabled). The power saving of the power saving mode may be achieved, e.g., by employing dedicated (low-power) wake-up signal radiotransmitter and / or receiver at at least one of the terminal device or the access node for communication of various wake-up signals, instead of employing a primary radio transmitter and / or receiver.

[0097] The access node may be configured to transition from a primary data communication mode to the power saving mode, for example, when there is very low demand for the cell coverage. The terminal device may be configured to transition from a primary data communication mode to the power saving mode at least when the terminal device observes that the access node that serves the terminal device or that operates a cell where the terminal device is camping is operating in the power saving mode (i.e., when the terminal device observes that the cell coverage has been deactivated).

[0098] In some embodiments, the terminal device may comprise a primary radio transmitter, a (dedicated) wake-up signal radio transmitter for transmission of uplink wake-up signals, a primary radio receiver and a (dedicated) wake-up signal radio receiver for reception of downlink wake-up signals. In such embodiments, in the power saving mode, the primary radio transmitter and receiver may be disabled and the dedicated wake-up signal radio transmitter and receiver may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio transmitter and / or receiver).

[0099] In some embodiments, the terminal device may comprise a primary radio transmitter (which may be usable also for the transmission of uplink wake-up signals), a primary radio receiver and a (dedicated) wake-up signal radio receiver for reception of downlink wake-up signals. In such embodiments, in the power saving mode, the primary radio receiver may be disabled, the primary radio transmitter may be enabled at least for transmission of uplink wake-up signals and the (dedicated) wake-up signal radio receiver may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio receiver). In these embodiments, the uplink wake-up signal may be narrow band such that using the primary radio transmitter for transmission of uplink wake-up signals could provide sufficient power spectral density for coverage with lower power and, hence, result in somewhat reduced power consumption.

[0100] In some embodiments, the terminal device may comprise a primary radio receiver (which may be usable also for the reception of downlink wake-up signals), a primary radio transmitter and a (dedicated) wake-up signal radio transmitter for transmission of uplink wakeup signals. In such embodiments, in the power saving mode, the primary radio transmitter may be disabled, the primary radio receiver may be enabled at least for reception of downlink wakeup signals and the (dedicated) wake-up signal radio transmitter may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio transmitter). Additionally or alternatively, orthogonal frequency division multiplexing (OFDM) based wake-up signals may be used, in these embodiments, at the primary radio transmitter.

[0101] In some embodiments, the terminal device may comprise (only) a primary radio transmitter and a primary radio receiver (i.e., no dedicated wake-up signal transmitter or receiver). In such embodiments, the power saving of the power saving mode may be achieved, e.g., by using OFDM-based wake-up signals may be used at the primary radio transmitter and / or receiver

[0102] In some embodiments, the access node may comprise a primary radio transmitter, a (dedicated) wake-up signal radio transmitter for transmission of downlink wake-up signals, a primary radio receiver and a (dedicated) wake-up signal radio receiver for reception of uplink wake-up signals. In such embodiments, in the power saving mode, the primary radio transmitter and receiver may be disabled and the dedicated wake-up signal radio transmitter and receiver may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio transmitter and / or receiver).

[0103] In some embodiments as discussed in the previous paragraph, the access node may be configured such that power consumption of the dedicated wake-up signal radio transmitter for periodic broadcasting of downlink wake-up signals is (at least) lower than a power consumption of the primary radio transmitter for periodic broadcasting of SSBs. Here, the broadcast periodicity may or may not be the same in the two cases. The lower power consumption of the dedicated wake-up signal radio transmitter when used for the broadcasting of the downlink wake-up signals may be based, e.g., on use of at least one of a narrower frequency bandwidth, a lower frequency band, more efficient power amplifier, a narrower beam, a lower transmit power and / or larger period of broadcasting (i.e., smaller broadcast periodicity) compared to the primary radio transmitter used for the broadcasting of the SSBs.

[0104] In some embodiments, the access node may comprise a primary radio transmitter (which may be usable also for the transmission of downlink wake-up signals), a primary radioreceiver and a (dedicated) wake-up signal radio receiver for reception of uplink wake-up signals. In such embodiments, in the power saving mode, the primary radio receiver may be disabled, the primary radio transmitter may be enabled at least for transmission of downlink wake-up signals and the (dedicated) wake-up signal radio receiver may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio receiver). In these embodiments, the downlink wake-up signal may be narrow band such that using the primary radio transmitter for transmission of downlink wake-up signals could provide sufficient power spectral density for coverage with lower power and, hence, result in somewhat reduced power consumption. Additionally or alternatively, OFDM-based wake-up signals may be used, in these embodiments, at the primary radio transmitter.

[0105] In some embodiments, the access node may comprise a primary radio receiver (which may be usable also for the reception of uplink wake-up signals), a primary radio transmitter and a (dedicated) wake-up signal radio transmitter for transmission of downlink wake-up signals. In such embodiments, in the power saving mode, the primary radio transmitter may be disabled, the primary radio receiver may be enabled at least for reception of uplink wake-up signals and the (dedicated) wake-up signal radio transmitter may be enabled. In the primary data communication mode, at least the primary radio transmitter and receiver may be enabled (optionally also the wake-up signal radio transmitter).

[0106] In some embodiments, the access node may comprise (only) a primary radio transmitter and a primary radio receiver (i.e., no dedicated wake-up signal transmitter or receiver). In such embodiments, the power saving of the power saving mode may be achieved, e.g., by using OFDM-based wake-up signals may be used at the primary radio transmitter and / or receiver.

[0107] In the above discussion pertaining to the power saving mode and the primary data communication mode, uplink and downlink wake-up signals may refer to any uplink and downlink wake-up signals usable by the terminal device or the access node (including the “special” wake-up signals for indicating cell activation and associated with an emergency event or other event requiring high-priority data communication, to be discussed below).

[0108] The access node broadcasts, in messages 201, downlink wake-up signals (DL WUSs) periodically with a first period (or equally with a first periodicity). The periodic broadcasting of downlink wake-up signal enables any terminal devices within reception rangeto maintain synchronization and knowledge about the presence of the (power saving) network. The (first) period of may be equally called a (first) duration of the power saving cycle. The access node may be assumed to also be monitoring for reception of uplink wake-up signals transmitted by terminal devices (e.g., as responses to the downlink wake-up signals). As mentioned above, these operations may relate to a power saving mode which is active at the access node. While messages 201 are illustrated in FIG. 2 with three arrows, this should not be considered as limiting in regards to the number of downlink wake-up signals broadcasted before the subsequent action in 202.

[0109] As mentioned above, the terminal device may be monitoring for reception of downlink wake-up signals broadcasted by the access node (or any access node). This operation may relate to a power saving mode which is active at the access node. Accordingly, the terminal device receives, in block 202, from the access node, the (broadcasted) downlink wake-up signals periodically with said first period. In general, the broadcasted downlink wake-up signals may be received by one or more terminal devices camping in at least one cell served by the access node (though only one terminal device is illustrated in FIG. 2 for simplicity).

[0110] The terminal device detects, in block 203, a need for data communication (i.e., a need for uplink data transmission and / or downlink data reception). The data to be transmitted / received may comprise application layer data, or it may comprise lower layer data related to network operation, for example.

[0111] Following the detecting of the need for the data communication in block 203, the terminal device may wait for reception of a next downlink wake-up signal (i.e., the next downlink wake-up signal following the detection of block 203) from the access node. The next downlink wake-up signal may be one that directly follows the detection in block 203. Said next downlink wake-up signal is broadcasted, by the access node, in message 204 and received by the terminal device in block 205.

[0112] Based on (or following) the detecting of the need for the data communication in block 203 and the (subsequent) reception of the next downlink wake-up signal in block 205, the terminal device transmits, in message 206, to the access node, an uplink wake-up signal for requesting activation of cell coverage at the access node.

[0113] Following the network configuration, the terminal device may not be allowed to indicate the need for the data communication before the next downlink wake-up signal. Saidwaiting for reception of the next downlink wake-up signal before transmission of the uplink wake-up signal enables power saving at the access node as the access node knows, in this case, (at least approximately) when to expect reception of uplink wake-up signals. In other words, the access node effectively controls periodicity for both downlink wake-up signal transmissions and uplink wake-up signal reception. The access node only needs to be woken up when the terminal device is requiring service (i.e., when a downlink wake-up signal is to be broadcasted and when one or more uplink wake-up signal may potentially be received).

[0114] In some alternative embodiments (not shown in FIG. 2), the terminal device may not wait for the reception of the next downlink wake-up signal before transmission of the uplink wake-up signal. In other words, some alternative embodiments may not contain elements 204, 205. Thus, the transmission of the uplink wake-up signal 206 may be carried out based on or following the detecting of the need for the data communication in block 203 but not based on the reception of the next downlink wake-up signal in block 205

[0115] The steps discussed in connection with elements 203, 205, 206 may be carried out in parallel also by zero or more further terminal devices not shown in FIG. 2. Thus, the access node receives, in block 207, one or more uplink wake-up signals from one or more terminal devices (including at least the terminal device shown in FIG. 2). Here, the one or more uplink wake-up signals may have been transmitted in response to (or as responses to) at least one of said downlink wake-up signals 201.

[0116] Then, the access node determines, in block 208, a second period (or a second periodicity) for the broadcasting of the downlink wake-up signals based at least on the one or more uplink wake-up signals received in block 207. In general, the second period may be smaller than the first period or larger than the first period. In some situations, the access node may decide to maintain the first period. For example, the determination of block 208 may be based on the number of the received one or more uplink wake-up signals. Additionally or alternatively, the determination of block 208 may be based on the number of consecutive broadcasts of the downlink wake-up signals for which at least one uplink wake-up signal was received as a response. In this manner, each terminal device contributes to the optimization of the network saving by influencing that the periodicity of the downlink wake-up signals is matched with the data traffic demand.

[0117] In some embodiments, the determining of the second period in block 208 may comprise determining the second period to be smaller than the first period (corresponding toan increase in broadcast periodicity) based on the number of the one or more uplink wake-up signals received in response to said downlink wake-up signal (message 204) being larger than or equal to a first pre-defined threshold. The first pre-defined threshold may have, for example, an (integer) value larger than or equal to two or an (integer) value larger than or equal to three or an (integer) value larger than or equal to four.

[0118] Alternatively, the determining of the second period in block 208 may comprise determining the second period to be smaller than the first period (corresponding to an increase in broadcast periodicity) based on the number of the consecutive broadcasts of the downlink wake-up signals (messages 201, 204) for which at least one uplink wake-up signal (or, more generally, at least a pre-defined number of uplink wake-up signals) was received as a response being larger than or equal to a second pre-defined threshold. The second pre-defined threshold may have, for example, an (integer) value larger than or equal to two or an (integer) value larger than or equal to three or an (integer) value larger than or equal to four.

[0119] Therefore, according to the last two paragraphs, the access node may determine that the downlink wake-up signal broadcast periodicity should be increased (i.e., the second period should be smaller relative to the first period) to improve network availability in view of the increased demand or need for cell coverage. In either of the two alternatives described above, the second period may be defined to be smaller than the first period by a fixed amount or by an amount determined based on the number of the one or more uplink wake-up signals or the number of the consecutive broadcasts for which at least one uplink wake-up signal was received as a response. In the latter cases, the decrease of the second period relative to the first period may optionally be limited by a fixed maximum amount of decrease. In some embodiments, a pre-defined lower limit for the second period may be defined (i.e., the second period cannot be defined to be smaller than said pre-defined lower limit).

[0120] In some embodiments, the determining of the second period in block 208 may comprise determining the second period to be larger than the first period (corresponding to a decrease in broadcast periodicity) based on the number of the one or more uplink wake-up signals received in response to said downlink wake-up signal (message 204) being smaller than or equal to a third pre-defined threshold. The third pre-defined threshold may have, for example, an (integer) value larger than or equal to one or larger than or equal to two or larger than or equal to three or larger than or equal to four. The third pre-defined threshold may be smaller than the first pre-defined threshold. If said number of the one or more uplink wake-upsignals falls between the third and first pre-defined thresholds, the second period may be equal to the first period (i.e., the first period may be maintained).

[0121] Alternatively, the determining of the second period in block 208 may comprise determining the second period to be larger than the first period based on the number of consecutive broadcasts of the downlink wake-up signals (messages 201, 204) for which at least one uplink wake-up signal was received as a response being smaller than or equal to a fourth pre-defined threshold. The fourth pre-defined threshold may have, for example, an (integer) value larger than or equal to one or larger than or equal to two or larger than or equal to three or larger than or equal to four. The fourth pre-defined threshold may be smaller than the second pre-defined threshold. If said number of consecutive broadcasts falls between the fourth and second pre-defined threshold, the second period may be equal to the first period (i.e., the first period may be maintained).

[0122] Therefore, according to the last two paragraphs, the access node may determine that the downlink wake-up signal broadcast periodicity should be decreased (i.e., the second period should be larger than the first period) to enable further power saving (especially at the access node). In either of the two alternatives of the last two paragraphs, the second period may be defined to be larger than the first period by a fixed amount or by an amount determined based on the number of the one or more uplink wake-up signals or the number of the consecutive broadcasts. In the latter cases, the increase of the second period relative to the first period may optionally be limited by a fixed maximum amount of increase. In some embodiments, a pre-defined upper limit for the second period may be defined (i.e., the second period cannot be defined to be larger than said pre-defined upper limit).

[0123] Optionally, the access node may transmit or broadcast, to at least the terminal device, a message defining a change from the first period to the second period (not shown in FIG. 2). Said message may comprise at least said second period. Said message may be a downlink wake-up signal.

[0124] Optionally, the access node may also evaluate based on the one or more uplink wake-up signals whether or not the cell coverage for at least one cell served by the access node should be activated. This functionality is discussed in detail in connection with FIG. 3.

[0125] Based the determining of the second period in block 208, the access node broadcasts, in messages 209, the downlink wake-up signals periodically with the second period(instead of the first period). The terminal device receives, in block 210, the broadcasted downlink wake-up signals (or at least some of them). The downlink wake-up signals broadcasted periodically with the second period may be received also by one or more further terminal devices.

[0126] The process of FIG. 2 may be repeated one or more times so as to increase broadcast periodicity (i.e., to decrease the broadcast period) iteratively until a threshold for restoring the cell coverage permanently is reached or to decrease the broadcast periodicity (i.e., to increase the broadcast period) iteratively to enable further power saving.

[0127] While FIG. 2 illustrates the specific case where at least the illustrated terminal device detects a need for performing data communication and, thus, transmits an uplink wakeup signal as a response to a next received downlink wake-up signal, in other cases, the access node may receive zero uplink wake-up signals as a response to the broadcasted downlink wakeup signal. In such a case, the determination of block 208 and subsequent broadcasting periodically with the second period of block 209 may still be carried out. Namely, the access node may determine a second period based at least on the fact that zero uplink wake-up signals were received. Any of the specific embodiments discussed in connection with block 208 may be applicable, mutatis mutandis, also in this case. In these cases, the second period may be defined to be longer than the first period, that is, the broadcast periodicity may be decreased.

[0128] The terminal device may have been configured before the execution of the process of FIG. 2 for performing the transmission of the uplink wake-up signal in the manner described above. For example, the access node may have transmitted, while still operating in a primary data communication mode, a configuration message to the terminal device, where the configuration message comprises configuration information related to the wake-up signal transmission. Alternatively, when the access node goes into the power saving mode, at least one access node adjacent to said access node and operating a primary data communication mode may have transmitted a configuration message to the terminal device, where the configuration message may comprise information related to at least one switched-off cell of the access node and configuration information relating to wake-up signal transmission. In either case, the configuration message may have been transmitted either in dedicated signalling or as broadcast information.

[0129] FIG. 3 illustrates signaling between an access node and a terminal device (i.e., UE) for enabling transitioning from a power saving mode to a primary data communicationmode according to embodiments in a power-efficient manner. The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a part thereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 3 shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at least some of said steps) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node.

[0130] The terminal device and the access node may be assumed to be operating during the process of FIG. 3 in a power saving mode until the transition to a primary data communication mode in blocks 312, 313. The power saving mode and the primary data communication mode may be defined as discussed in connection with FIG. 2.

[0131] The initial steps 301 to 306 of the process of FIG. 3 may correspond to steps 201 to 206 of FIG. 2 and are, thus, not discussed here in detail. In summary, the access node is initially periodically broadcasting, in messages 301, downlink wake-up signals, at least some of which may be received by the terminal device in block 302. The terminal device detects, in block 303, a need for data communication (e.g., uplink data transmission and / or downlink data reception). Thereafter, upon receiving the next downlink wake-up signal 304 broadcasted by the access node in block 305, the terminal device transmits, in message 306, an uplink wakeup signal to the access node. Similar to as discussed in connection with FIG. 2, actions pertaining to elements 304, 305 may be omitted, in some embodiments. Also similar to as discussed in connection with FIG. 2, actions pertaining to blocks 302, 303, 305, 306 may be carried out in parallel also by one or more further terminal devices (not shown in FIG. 3 for simplicity).

[0132] Here, the access node receives, in block 307, from one or more terminal devices (including at least the terminal device shown in FIG. 3) within a pre-defined time window, one or more uplink wake-up signals for requesting activation of cell coverage of at least one cell served by the access node. Here, the pre-defined time window may correspond to a pre-defined number of one or more downlink wake-up signal broadcast occasions (i.e., to a pre-defined number of one or more broadcast periods).

[0133] The access node determines, in block 308, that the number of the one or more uplink wake-up signals received within the pre-defined time window exceeds a pre-defined (cell coverage) activation threshold. The pre-defined activation threshold may have an integer value larger than or equal to one, that is, a single received uplink wake-up signal may not be sufficient for cell coverage activation. The pre-defined activation threshold may be equally called a first pre-defined activation threshold (so as to distinguish it from the second predefined activation threshold to be discussed in connection with FIG. 5).

[0134] Based on the number of the one or more uplink wake-up signals received within the pre-defined time window exceeding the pre-defined activation threshold in block 308, the access node triggers (and carries out), in block 309, activation of cell coverage for at least one cell served by the apparatus.

[0135] In some embodiments, the activating of the cell coverage for the at least one cell may be performed in two or more (time) steps so that, at a first step, a bandwidth at the at least one cell is set to an initial (reduced) value and, at each subsequent step, the bandwidth at the at least one cell is increased compared to a previous step. The bandwidth increase at each step may be defined to have fixed value or it may be defined dynamically based on (current) demand for cell coverage. Thus, when using the latter option, the access node may monitor the demand for cell coverage during the step-wise cell coverage activation process. The demand for the cell coverage may be quantified here, e.g., by the number of requests for uplink and / or downlink data communication received during the step-wise cell coverage activation process and / or the amount of data transmitted during the step-wise cell coverage activation process. At least in some embodiments, the activation of the cell coverage for the at least one cell in the two or more steps may mean that the primary radio receiver of the access node is activated in two or more steps.

[0136] The access node broadcasts (or transmits), in message 310, a cell coverage activation downlink wake-up signal indicating the activation of the cell coverage at least to the terminal device. The broadcasting of message 310 may be based on or form a part of the triggering of the cell coverage activation in block 309. The broadcasting of message 310 may be carried out before or (immediately) after the activation of cell coverage. Said cell coverage activation downlink wake-up signal may differ from the downlink wake-up signal broadcasted as messages 302. The cell coverage activation downlink wake-up signal may have or possess a characteristic (e.g., an indicator or other piece of data) that distinguishes it from otherdownlink wake-up signals (that is, at least from the “normal” downlink wake-up signals of element 301). The terminal device receives, in block 311, the cell coverage activation downlink wake-up signal from the access node.

[0137] The terminal device transitions, in block 312, from the power saving mode to the primary data communication mode. Said transitioning in block 312 may be performed based on (or in response to or following) the reception of the cell coverage activation downlink wakeup signal in block 311. Similarly, the access node transitions, in block 313, from the power saving mode to the primary data communication mode. Said transitioning in block 313 may be performed in response to, following or as a part of the triggering of the activation of the cell coverage.

[0138] After the terminal device and the access node have transitioned to use the respective primary data communication modes, uplink and / or downlink data communication may be carried out, in block 314, between them. Said uplink and / or downlink data communication may comprise, e.g., at least transmission (or specifically broadcasting) of one or more SSBs from the access node to the terminal device. The SSBs may broadcasted periodically.

[0139] FIG. 3 illustrates the positive case where the number of the one or more uplink wake-up signals received within the pre-defined time window exceeds a pre-defined (cell coverage) activation threshold. If this is not the case (i.e., the number of the one or more uplink wake-up signals received within the pre-defined time window fails to exceed the pre-defined activation threshold), the access node may not trigger the activation of cell coverage. This applies also if no uplink wake-up signals are received within the pre-defined time window.

[0140] FIG. 4 illustrates signaling between an access node and a terminal device (i.e., UE) for enabling transitioning from a primary data communication mode to a power saving mode at the terminal device and the access node to according to embodiments in a powerefficient manner. The process of FIG. 4 may follow the execution of the process of FIG. 3. The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a part thereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 4 shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at leastsome of said steps) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node.

[0141] The terminal device and the access node may be assumed to be operating during the process of FIG. 4 in a primary data communication mode until the transition to a power saving mode in blocks 405, 406. The power saving mode and the primary data communication mode may be defined as discussed in connection with FIG. 2.

[0142] The access node detects, in block 401, a need for deactivation (or disabling) of cell coverage relating to at least one cell served by the access node. For example, the access node may determine, in block 401, that the number of requests for uplink and / or downlink data communication within a pre-defined time window and / or the amount of data transmitted and / or received within a pre-defined time window is below a pre-defined deactivation threshold. Alternatively, the detection of block 401 may be based on a deactivation request received from a core network.

[0143] Thus, based on the detection in block 401, the access node triggers, in block 402, gradual deactivation of the cell coverage. The gradual deactivating of the cell coverage for the at least one cell is performed (gradually) in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step. Said initial value may correspond a reduced value relative to the bandwidth at the moment of the detection of the need for deactivation of the cell coverage. The last step of said two or more steps may correspond to setting the bandwidth to zero (i.e., fully deactivating the cell coverage).

[0144] During the gradual deactivation of the cell coverage (i.e., gradual decreasing of cell bandwidth), the access node may transmit, to one or more terminal devices in said at least one cell (including at least the terminal device shown in FIG. 4), a plurality of scheduling control messages so as to schedule time-frequency resources employing the gradually decreasing bandwidth of the least one cell. Each scheduling control message transmitted to a given terminal device may indicate scheduling of zero or more time-frequency resources for a next transmission time instance. As the bandwidth is gradually reduced in block 402, the total number of time-frequency resources which may be scheduled by the access node decreases.

[0145] Following (or based on) the (full) deactivation of the cell coverage in block 402, the access node transmits, in message 403, to at least one terminal device (including theterminal device shown in FIG. 4), a message indicating the deactivation of the cell coverage. The terminal device receives, in block 404, the message indicating the deactivation of the cell coverage from the access node. Said message may be a paging message. In other words, the deactivation of the cell coverage may be communicated to the terminal device via paging information. Thus, the terminal device may be operating in idle mode monitoring paging during block 404.

[0146] In some alternative embodiments, the message 403 may be transmitted before the full deactivation of the cell coverage (i.e., while the gradual deactivation of the cell coverage is still on-going). For example, the message 403 may be transmitted between the penultimate and last of said two or more steps for decreasing the cell bandwidth. Alternatively, the message 403 may be transmitted when the bandwidth of the at least one cells falls below a pre-defined threshold.

[0147] Based on (or following) the reception of the message in block 404, the terminal device transitions, in block 405, from the primary data communication mode to the power saving mode. Thereafter, the terminal device may carry out, for example, any of the functionalities discussed in connection with any of FIGs. 2 to 3. Similarly, following or based on the deactivation of the cell coverage (or as a part of the deactivation process), the access node also transitions, in block 406, from the primary data communication mode to the power saving mode.

[0148] In some alternative embodiments, the deactivation of the cell coverage in block 402 may not be gradual but be performed in a single step. In other words, the cell coverage may be simply switched off. In such embodiments, the message 402 may be transmitted either before or after the deactivation.

[0149] It should be noted that the adaptation of the period of the downlink wake-up signals to the traffic demand and the gradual increase / decrease of the cell bandwidth associated with the cell (de)activation are separate embodiments and the gradual increase / decrease of the cell bandwidth may be carried out without the adaptation of the period of the downlink wakeup signals when the cell coverage has been deactivated. They do provide a synergistic effect in the sense that the combination of the two embodiments provides the best capabilities of optimizing the power-savings.

[0150] FIG. 5 illustrates signaling between an access node, a terminal device (i.e., UE) and a core network (CN) for enabling transitioning from a power saving mode to a primary data communication mode at the terminal device and the access node according to embodiments in a power-efficient manner. Specifically, FIG. 5 illustrates a case where this transition is triggered by the network, as opposed to by the terminal device as discussed previously in connection with FIG. 3. The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a part thereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 5 shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at least some of said steps) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node.

[0151] The terminal device and the access node may be assumed to be operating during the process of FIG. 5 in a power saving mode until the transition to a primary data communication mode in blocks 509, 510. The power saving mode and the primary data communication mode may be defined as discussed in connection with FIG. 2.

[0152] Similar to previously discussed processes, the access node broadcasts, in messages 501, downlink wake-up signals periodically (with a first period). At least some of the downlink wake-up signal may be received, in block 502, by the terminal device (and optionally one or more further terminal devices).

[0153] One or more core network nodes of a core network transmit, in messages 503, to the access node, one or more requests for activation of cell coverage associated with at least one cell served by the access node. The one or more requests may be requests for downlink data transmission (which requires activation of the cell coverage). The access node receives, in block 504, said one or more requests. In some embodiments, the one or more requests may be received within a pre-defined time window. The starting point for the pre-defined time window may be the reception of the initial request.

[0154] The access node determines, in block 505, that the cell coverage should be activated based at least on the received one or more requests. In other words, the access node detects, in block 505, a need for activation of the cell coverage based at least on the received one or more requests.

[0155] In some embodiments, the determination of block 505 may comprise determining that the number of the one or more requests exceeds a second pre-defined activation threshold. In other words, after reception of the initial request from the core network, the access node may buffer any further requests for cell coverage activation till the number of the received requests exceeds the second pre-defined activation threshold. A counter for the number of the received requests may be reset to zero after the pre-defined time window has passed. In other words, the number of the one or more requests received within the pre-defined time window (starting from the reception of the initial request) should exceed the second pre-defined activation threshold for triggering activation of the cell coverage. In other embodiments, no time window is employed for counting the number of the one or more requests. In other words, the buffering of the received requests may continue until the second pre-defined activation threshold is exceeded. The second pre-defined activation threshold may have an integer value equal to or larger than 0 or equal to or larger than 1 or equal to or larger than 2.

[0156] In other embodiments, the determination of block 505 may comprise determining that a pre-defined amount of time has passed since reception of an initial one of the one or more requests. In other words, after reception of the initial request from the core network, the access node may buffer any further requests for cell coverage activation for the pre-defined amount of time before taking steps for restoring the cell coverage.

[0157] Following the detecting of the need for the activation of the cell coverage in block 505, the process may proceed in elements 506 to 511 as discussed previously in connection with elements 309 to 314 of FIG. 3. These steps are not discussed here for brevity.

[0158] In some embodiments, the access node may, additionally or alternatively, be capable of directly activating the cell coverage without needing to satisfy any of the requirements discussed in connection with block 504.

[0159] FIG. 6 illustrates signaling between an access node and a terminal device (i.e., UE) for enabling immediate transitioning from a power saving mode to a primary data communication mode at the terminal device and the access node according to embodiments upon detecting a need for high-priority data communication (e.g., detecting an emergency event or other high-priority event). The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a partthereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 6 shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at least some of said steps) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node (e.g., at least steps relating to elements 602, 608, 609).

[0160] The terminal device and the access node may be assumed to be operating during the process of FIG. 6 in a power saving mode until the transition to a primary data communication mode in blocks 609, 610. The power saving mode and the primary data communication mode may be defined as discussed in connection with FIG. 2.

[0161] Similar to previously discussed processes, the access node broadcasts, in messages 601, downlink wake-up signals periodically (with a first period) At least some of the downlink wake-up signal may be received, in block 502, by the terminal device (or optionally one or more further terminal devices). The terminal device may be located at a cell of the access node (that is, the access node which has deactivated the cell coverage at least for that cell).

[0162] The terminal device detects, in block 603, an event (e.g., a call) requiring (urgent) high-priority data communication. The high-priority data communication may be defined as data communication having priority greater than a threshold (e.g., a pre-defined threshold).

[0163] In some embodiments, a priority level value associated with the high-priority data communication (i.e., to be used for scheduling the high-priority data communication) may be assumed or expected to be smaller than a pre-defined threshold value. In other words, high-priority data communication may be defined data communication associated priority level value smaller than the pre-defined threshold value. Here, it is assumed that the priority level is defined such that a low priority level value corresponds to high priority and vice versa. For example, the priority level values may be 5G quality of service identifier (5QI) values. In the case of 5QI priority level values, the pre-defined threshold value may be, for example, 6.

[0164] The event requiring high-priority data communication may be, for example, a high-priority call such as an emergency call or a multimedia priority service (MPS) call. Alternatively, said event may be a high-priority non-call-communication event (e.g., an event relating to messaging, an alert or mission-critical data transfer). Said high-priority non-callcommunication event may also be an emergency or MPS event. An emergency event may be defined as an event relating to communication with (local) emergency services. An emergencycall may be defined as a call directed to an emergency phone number (i.e., to a phone number that allows a caller to contact local emergency services for assistance). MPS (sometimes called High Priority Access, HP A) is a service enabling certain pre-defined subscribers (e.g., rescue personnel and other authorized emergency personnel) to get priority access. The priority associated with MPS may be even higher than the priority associated with emergency calls. MPS is designed by 3GPP as a component of National Security / Emergency Preparedness (NS / EP) in Internet Protocol Multimedia Subsystem (IMS) networks. MPS enables authorized emergency personnel to coordinate their efforts by applying high priority to their communications.

[0165] In some embodiments, the event requiring high-priority data communication may be a high-priority service. The high-priority service may be or correspond to an application executed in the terminal device. Said application may utilize a high-priority communication service provided by the network. The communication associated with the high-priority service may employ, e.g., a high-priority network slice or a traffic class above a certain threshold. In the case of the first example, the high-priority service may be called a slice service. A slice service refers to a specific type of service provided within a network slice, where a network slice is a logically separated and customized segment of the network designed to meet particular service requirements. The slice service requiring high-priority data communication may be, for example, an Ultra-Reliable Low-Latency Communication (URLLC) service.

[0166] The terminal device transmits, in message 604, to an access node, high-priority uplink wake-up signal for immediate activation of cell coverage at the access node (or at least expedited activation of the cell coverage at the access node compared to the activation triggered using the “default” uplink wake-up signal 306 of FIG. 3). The transmitting of the high-priority uplink wake-up signal in message 604 may be performed based on or immediately following or (directly) in response to the detection of block 603. Thus, the terminal device may not, in this case, wait for reception of the next downlink wake-up signal before transmitting the high-priority uplink wake-up signal, in contrast to some embodiments of the process of FIG. 2. Namely, it may be considered more important to communicate the need for immediate activation of the cell coverage to the access node as quickly as possible than performing said communication in a maximally power-efficient manner. At least in some embodiments, the high-priority wake-up signal may be called an emergency wake-up signal.

[0167] The high-priority uplink wake-up signal may have or comprise a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals, that is, from other types of uplink wake-up signals (e.g., at least from the “default” uplink wakeup signal discussed in connection with previous embodiments). This may be a general property of high-priority uplink wake-up signals (i.e., it may not be applicable only for the particular high-priority uplink wake-up signal of message 604). For example, the high-priority uplink wake-up signal may comprise a cause value, an indicator, or an information element indicating that the uplink wake-up signal is of a special type that pertains to high-priority data communication (e.g., emergency or MPS data communication).

[0168] The access node receives, in block 604, the high-priority uplink wake-up signal. In response to the reception of the high-priority uplink wake-up signal in block 604, the access node triggers, in block 605, the activation of the cell coverage for at least one cell served by the access node. Here, the at least one cell may comprise at least the cell of the terminal device. It should be emphasized that the triggering of the activation of the cell coverage in block 605 may be carried out, in this case, directly in response to or directly following the reception of the high-priority uplink wake-up signal. Thus, the access node does not wait for reception of any further (high-priority) uplink wake-up signals from any terminal device following the reception of the high-priority uplink wake-up signal in block 604, in contrast to the operation discussed in connection with blocks 307, 308, 309 of FIG. 3. Also in contrast to the process of FIG. 3, the access node may not evaluate the received high-priority uplink wake-up signal against any pre-defined conditions before the activation of the cell coverage.

[0169] The steps relating to the activation of the cell coverage relating to elements 606 to 611 may correspond to elements 309 to 314 of FIG. 3. However, here, it may be assumed the uplink and / or downlink data communication of block 611 comprises at least high-priority data communication relating to the event detected in block 603.

[0170] FIG. 7 illustrates signaling between an access node and a terminal device (i.e., UE) for configuring uplink wake-up signal transmission functionalities according to any of the embodiments discussed above. The terminal device may be, for example, one of terminal devices 100, 102 of FIG. 1 or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node (e.g., access node 104 of FIG. 1) or a part thereof or a distributed access node or a part thereof (e.g., a DU 104 or CU 108 of FIG. 1). It should be appreciated that while FIG. 7shows only a single terminal device for simplicity of presentation, in general, the steps carried out by the terminal device (or at least some of said steps) may be carried out simultaneously by one or more terminal devices camping in at least one cell served by the access node (e.g., at least steps relating to elements 602, 608, 609.

[0171] The terminal device and the access node may be assumed to be operating during the process of FIG. 7 in a primary data communication mode. The primary data communication mode may be defined as discussed in connection with FIG. 2.

[0172] The process of FIG. 7 may be carried out before the execution of any of the processes of FIGs. 2, 3, 5 & 6. Considering such consecutive execution of the process of FIG.7 and any of the processes of FIGs. 2, 3, 5 & 6, the access node of FIG. 7 may or may not be the access node shown in FIGs. 2, 3, 5 & 6. Between the execution of the process of FIG. 7 and any of the processes of FIGs. 2, 3, 5 & 6, the terminal device and the access node may transition from the primary data communication mode to the power saving mode (e.g., as discussed in connection with FIG. 4).

[0173] The access node transmits, in message 701, a configuration message to the terminal device. The configuration message may be transmitted either in dedicated signaling (e.g., radio resource control, RRC, signaling) or as broadcasted (system) information. The terminal device receives, in block 702, the configuration message. The terminal device may store at least some of the contents of the configuration message to at least one memory.

[0174] The configuration message (message 701) comprises configuration information relating to uplink wake-up signal transmissions. Said configuration information may comprise a configuration for implementing the uplink wake-up signal transmission functionalities of any of FIGs. 2 or 3 and / or the high-priority uplink wake-up signal transmission functionalities of FIG. 6. The configuration for implementing the uplink wake-up signal transmission functionalities of FIG. 3 may comprise, for example, a broadcasting period (or periodicity) of downlink wake-up signals and / or resource allocation. The configuration for implementing the high-priority uplink wake-up signal transmission functionalities of FIG. 6 may comprise, for example, a composition of the high-priority uplink wake-up signal (including, e.g., a cause value or other indicator or property indicating an emergency or high priority). In some embodiments, the configuration message may define a composition of the cell coverage activation downlink wake-up signal.

[0175] In some alternative embodiments, when an access node goes into the power saving mode, at least one access node which is adjacent to said access node and is operating in a primary data communication mode may transmit the configuration message (i.e., message 701) to the terminal device. In this case, the configuration message may comprise also information on at least one switched-off (or deactivated) cell of the access node operating in the power saving mode.

[0176] The blocks, related functions, and information exchanges described above by means of FIGs. 2 to 7 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the given one. Other functions can also be executed between them or within them, and other information may be sent, and / or other rules applied. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of the block or one or more pieces of information.

[0177] The embodiments discussed above in connection with FIGs. 2 to 7 provide at least the following benefits:• The access node is able to control the duration of the power saving cycle (i.e., periodicity of the downlink and uplink wake-up signal transmissions) and the wake up of the main radio receiver at the access node which, in turn, enables power saving both at the terminal device and at the access node.• The adjusting of the periodicity (or period) of uplink wake-up signal transmissions of the terminal device for requesting uplink and / or downlink data communication based on the number of uplink wake-up signals received at the access node is enabled. Thus, the wake-up of the cell coverage associated with at least one cell may be carried out according to the actual need for activating cell coverage in the at least one cell.• The access node is enabled to control selecting of the periodicity (or equally period) for both receiving and transmitting wake-up signals and hence the control on possible frequency of switching on / off the main radio receiver(s) and / or transmitter(s) through the proposed procedure for wake-up signal transmission. This serves to maximize the network power saving while also enabling power saving for terminal devices.The activation of the main radio receiver of the access node could be performed in steps with cell bandwidth increased according to the number of requests for data traffic.

[0178] FIG. 8 provides an apparatus 801 according to some embodiments. Specifically, FIG. 8 may illustrate an apparatus 801 configured to carry out at least some of the functions described above. The apparatus 801 may be or form a part of a terminal device. Said terminal device may be a terminal device 100, 102 of FIG. 1. Alternatively, the apparatus may be or form a part of an access node (being a non-distributed or distributed access node) or a part thereof. In some embodiments, the terminal device may be an loT device or a wearable device. The access node may be, for example, a non-distributed access node 104 of FIG. 1 or a part thereof or a DU 104 or CU 108 of FIG. 1.

[0179] The apparatus 801 may comprise one or more communication control circuitry 820, such as at least one processor, and at least one memory 830, including one or more algorithms 831, such as a computer program code (software) wherein the at least one memory and the computer program code (software) are configured, with the at least one processor, to cause the apparatus 801 to carry out any one of the exemplified functionalities of the apparatus (i.e., of the terminal device or the access node) described above in connection with any of FIGs.2 to 7. Said at least one memory 830 may also comprise at least one database 832.

[0180] In some embodiments, the apparatus 801 may comprise or be connected to a primary radio transmitter, a primary radio receiver, a (dedicated) wake-up signal radio transmitter and a (dedicated) wake-up signal radio receiver. In other embodiments, the apparatus 801 may comprise or be connected to a primary radio transmitter, a primary radio receiver and at least one of a (dedicated) wake-up signal radio transmitter or a (dedicated) wake-up signal radio receiver.

[0181] When the one or more communication control circuitry 820 comprises more than one processor, the apparatus 801 may be a distributed device wherein processing of tasks takes place in more than one physical unit. Each of the at least one processor may comprise one or more processor cores.

[0182] Referring to FIG. 8, the one or more communication control circuitry 820 of the apparatus 801 is configured to carry out functionalities described above by means of any of elements of FIGs. 2 to 7 using one or more individual circuitries. It may also be feasible to usespecific integrated circuits, such as DSP block, digital signal processor, ASIC or FPGA, or other components and devices for implementing said functionalities in accordance with different embodiments.

[0183] Referring to FIG. 8, the apparatus 801 may further comprise different interfaces (I / F) 810 such as one or more communication interfaces comprising hardware and / or software for realizing communication connectivity according to one or more communication protocols. For example, if the apparatus 801 is a terminal device, the one or more communication interfaces 810 may comprise at least one interface enabling communication between the apparatus 801 and one or more access nodes (e.g., an access node providing a primary cell and / or one or more access nodes providing one or more secondary cells) and / or at least one interface enabling communication between the apparatus and one or more (other) terminal devices. If the apparatus 801 is an access node, the one or more communication interfaces 810 may comprise at least one interface enabling communication between the apparatus 801 and one or more terminal devices, at least one interface enabling communication between the apparatus 801 and one or more core network nodes and / or at least one interface enabling communication between the apparatus 801 and one or more other access nodes. The interfaces 810 may also comprise at least one user interface.

[0184] Referring to FIG. 8, the memory 830 may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.

[0185] As used in this application, the term ‘circuitry’ may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software (and / or firmware), such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software, including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a terminal device or an access node, to perform various functions, and (c) hardware circuit(s) and processor(s), such as a microprocessor(s) or a portion of a microprocessor s), that requires software (e.g. firmware) for operation, but the software may not be present when it is not needed for operation. This definition of ‘circuitry’ applies to all uses of this term in this application, including any claims. As a further example, as used in this application, the term‘circuitry’ also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware.

[0186] In an embodiment, at least some of the processes described in connection with FIGs. 2 to 7 may be carried out by an apparatus comprising corresponding means for carrying out at least some of the described processes. Some example means for carrying out the processes may include at least one of the following: detector, processor (including dual-core and multiple-core processors), digital signal processor, controller, receiver, transmitter, encoder, decoder, memory, register, multiply-accumulate (MAC) unit, delay element, RAM, ROM, software, firmware, display, user interface, display circuitry, user interface circuitry, user interface software, display software, circuit, filter (low-pass, high-pass, bandpass and / or bandstop), sensor, circuitry, inverter, capacitor, inductor, resistor, operational amplifier, diode and transistor. In some embodiments, at least some of the processes may be implemented using discrete components. In an embodiment, at least some of the processes described in connection with FIGs. 2 to 7 may be carried out by an apparatus comprising corresponding hardware means for carrying out at least some of the described processes. Said hardware means may comprise at least one of: a multiplier, an adder, a MAC unit, a barrel shifter, a register, a shift register, a memory unit, a control logic, a clocking circuitry or a finite state machine.

[0187] According to an embodiment, there is provided an apparatus (e.g., a terminal device) comprising means for performing:receiving, from an access node, downlink wake-up signals periodically with a first period;detecting a need for data communication;based on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of cell coverage at the access node; andfollowing the transmitting, receiving, from the access node, downlink wake-up signals periodically with a second period different from the first period..

[0188] According to an embodiment, there is provided an apparatus (e.g., an access node) comprising means for performing:broadcasting downlink wake-up signals periodically with a first period;receiving, in response to at least one of said downlink wake-up signals, zero or more uplink wake-up signals from zero or more terminal devices;determining a second period for the broadcasting of the downlink wake-up signals based on the received zero or more uplink wake-up signals; andbroadcasting, based on said determining, the downlink wake-up signals periodically with the second period.

[0189] According to an embodiment, there is provided an apparatus (e.g., a terminal device) comprising means for performing:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell; andbased on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

[0190] According to an embodiment, there is provided an apparatus (e.g., an access node) comprising means for performing:detecting a need for deactivation of cell coverage for at least one cell served by the apparatus;based on the detection, triggering deactivation of the cell coverage, wherein the deactivating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step; andafter or during the deactivation of the cell coverage, transmitting, to one or more terminal devices, a message indicating the deactivation of the cell coverage.

[0191] According to an embodiment, there is provided an apparatus (e.g., a terminal device) comprising means for performing:receiving, while operating in a power saving mode in a cell that has deactivated cell coverage, downlink wake-up signals periodically;detecting, in the power saving mode, an event requiring high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority greater than a threshold; andtransmitting, to an access node, a high-priority uplink wake-up signal for immediate activation of cell coverage at the access node, wherein the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals.

[0192] According to an embodiment, there is provided an apparatus (e.g., an access node) comprising means for performing:receiving, while operating in a power saving mode, a high-priority uplink wakeup signal indicating a need for high-priority data communication, wherein the high-priority data communication is defined as data communication having a priority higher than a threshold, and the high-priority uplink wake-up signal has a characteristic that distinguishes the high-priority uplink wake-up signal from other uplink wake-up signals; andin response to the reception of the high-priority uplink wake-up signal, triggering activation of cell coverage for at least one cell served by the apparatus.

[0193] Embodiments as described above may also be carried out, fully or at least in part, in the form of a computer process defined by a computer program or portions thereof. Embodiments of the methods described in connection with FIGs. 2 to 7 may be carried out by executing at least one portion of a computer program comprising corresponding instructions. The computer program may be provided as a computer readable medium comprising program instructions stored thereon or as a non-transitory computer readable medium comprising program instructions stored thereon. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a recordmedium, computer memory, read-only memory, electrical carrier signal, tele-communications signal, and software distribution package, for example. The computer program medium may be a non-transitory medium. Coding of software for carrying out the embodiments as shown and described is well within the scope of a person of ordinary skill in the art.

[0194] The term “non-transitory”, as used herein, is a limitation of the medium itself (that is, tangible, not a signal) as opposed to a limitation on data storage persistency (for example, RAM vs. ROM).

[0195] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present solution. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

[0196] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present solution may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present solution.

[0197] Even though embodiments have been described above with reference to examples according to the accompanying drawings, it is clear that the embodiments are not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.INDUSTRIAL APPLICABILITY

[0198] At least some embodiments find industrial application in wireless communications.

Claims

CLAIMS1. An apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell; and based on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

2. The apparatus of claim 1, wherein the message is a paging message.

3. The apparatus according to any preceding claim,wherein the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orwherein the apparatus comprises a primary radio transmitter usable for transmission of uplink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of downlink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of uplink wake-up signals duringoperation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

4. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:receiving, while operating in the power saving mode, a cell coverage activation downlink wake-up signal indicating activation of the cell coverage for said at least one cell of the access node from the access node; andbased on the cell coverage activation downlink wake-up signal, transitioning from the power saving mode to the primary data communication mode.

5. The apparatus of claim 4, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform, following the transitioning from the power saving mode to the primary data communication mode:receiving, from the access node, a second plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more timefrequency resources for a next transmission time instance, the received second plurality of scheduling control messages corresponding to scheduling performed during a gradual increase of bandwidth at the at least one cell in two or more steps following the activation of the cell coverage.

6. The apparatus of claim 4 or 5, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform, before the reception of the cell coverage activation downlink wake-up signal:detecting, while operating in the power saving mode, a need for data communication; based at least on the detecting of the need for the data communication, transmitting, to the access node, an uplink wake-up signal for requesting activation of the cell coverage at the access node.

7. An apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:54detecting a need for deactivation of cell coverage for at least one cell served by the apparatus;based on the detection, triggering deactivation of the cell coverage, wherein the deactivating of the cell coverage for the at least one cell is performed in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial value and, at each subsequent step, the bandwidth at the at least one cell is decreased compared to a previous step; andafter or during the deactivation of the cell coverage, transmitting, to one or more terminal devices, a message indicating the deactivation of the cell coverage.

8. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:during the gradual deactivation of the cell coverage, transmitting, to the one or more terminal devices in said at least one cell, a plurality of scheduling control messages so as to schedule time-frequency resources employing the gradually decreasing bandwidth of the least one cell.

9. The apparatus according to any of claims 7 to 8, wherein the message is a paging message.

10. The apparatus according to any of claims 7 to 9, wherein the gradual deactivating of the cell coverage for the at least one cell is based on the number and / or capacity requirements of the one or more terminal devices in said at least one cell.

11. The apparatus according to any of claims 7 to 10, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform the detection, the triggering of the deactivation and the transmitting of the message while operating in a primary data communication mode, and to perform:after the deactivation of the cell coverage, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

12. The apparatus of claim 11,55wherein the apparatus comprises a primary radio transmitter, a dedicated wake-up signal radio transmitter for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio transmitter and receiver being disabled and the dedicated wake-up signal radio transmitter and receiver being enabled during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode, orwherein the apparatus comprises a primary radio transmitter usable for transmission of downlink wake-up signals, a primary radio receiver and a dedicated wake-up signal radio receiver for reception of uplink wake-up signals, the primary radio receiver being disabled, the dedicated wake-up signal radio receiver being enabled and the primary radio transmitter being enabled at least for the transmission of downlink wake-up signals during operation in the power saving mode, and at least the primary radio transmitter and receiver being enabled during operation in the primary data communication mode.

13. The apparatus of claim 11 or 12, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform:detecting, while operating in the power saving mode, a need for activation of the cell coverage; andbased on the detecting of the need for the activation of the cell coverage, broadcasting a cell coverage activation downlink wake-up signal indicating activation of the cell coverage for said at least one cell and activating the cell coverage, wherein the activating of the cell coverage comprises transitioning from the power saving mode to the primary data communication mode.

14. The apparatus of claim 13, wherein the detecting the need for the activation of the cell coverage comprises:receiving, from one or more terminal devices within a pre-defined time window, one or more uplink wake-up signals for requesting the activation of the cell coverage; and determining that the number of the one or more uplink wake-up signals received within the pre-defined time window exceeds a first pre-defined activation threshold.5615. The apparatus of claim 13, wherein the detecting the need for the activation of cell coverage comprises:receiving, from a core network, one or more requests for the activation of the cell coverage; anddetermining that the number of the one or more requests exceeds a second pre-defined activation threshold; ordetermining that a pre-defined amount of time has passed since reception of an initial one of the one or more requests.

16. The apparatus according to any of claims 13 to 15, wherein the activating of the cell coverage for the at least one cell is performed gradually in two or more steps so that, at a first step, a bandwidth at the at least one cell is set to an initial reduced value and, at each subsequent step, the bandwidth at the at least one cell is increased compared to a previous step.

17. A method comprising:receiving, from an access node, while operating in a primary data communication mode, a plurality of scheduling control messages, wherein each scheduling control message indicates scheduling of zero or more time-frequency resources for a next transmission time instance, the received plurality of scheduling control messages corresponding to scheduling performed during a gradual decrease of bandwidth at at least one cell served by the access node in two or more steps before full deactivation of a cell coverage;receiving, from the access node after or during said gradual decrease of bandwidth, a message indicating a deactivation of the cell coverage for the at least one cell, andbased on the reception of the message, transitioning from the primary data communication mode to a power saving mode having reduced data communication capability compared to the primary data communication mode.

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