User equipment, network node and radio communication method

This continuation application claims priority to and the benefit of U.S. application Ser. No. 15/771,758 filed on Apr. 27, 2018. U.S. application Ser. No. 15/771,758 is a national phase application of International Application No. PCT/EP2016/077083 filed Nov. 9, 2016 and published in the English language. International Application No. PCT/EP2016/077083 claims priority to European Application No. EP15194255.4 filed on Nov. 12, 2015. The entireties of the aforementioned applications are incorporated herein by reference.

Embodiments of the invention relate to wireless communication. Embodiments of the invention relate in particular to a signalling between a user equipment and a radio access network node that determines whether the user equipment will listen for paging signals.

With increasing popularity of mobile data communication, an ever increasing number of devices is equipped with a radio interface for communication with a cellular communication network. Sensors and wearable devices are examples for devices that may be operative for communication with a cellular network.

While some kinds of user equipments are expected to provide high data rates, such as smartphones or portable computers, battery lifetime is of significant importance for other types of user equipments that may not require high data rates. Sensors, wearable devices, or other units that infrequently transmit small amounts of data and which may accommodate long downlink latencies are examples of devices for which long battery lifetime is particularly relevant. Further, in view of the ever increasing number of user equipments that is deployed for communication with a cellular network radio resource usage becomes a relevant issue. Techniques that may assist reducing radio access network loads become increasingly important.

With massive deployment of user equipments such as sensors or other devices that may accommodate high latency in downlink data transmissions, listening for paging signals may be a significant source of energy consumption of the user equipment. Discontinuous reception, DRX, schemes which include periods where the user equipment does not need to monitor system information or receive page signals and which include periods in which the user equipment wakes up to listen for potential pages intended to the user equipment may reduce power consumption. However, the periods in which the user equipment wakes up to listen for pages may reduce battery lifetime, and the paging of user equipments that do not need to receive pages may add to radio access network loads.

There is a continued need in the art for devices, systems and methods which mitigate at least some of the above shortcomings. There is a need for devices, systems and methods that allow user equipment battery lifetime to be extended and/or that allow radio access network loads to be reduced.

According to embodiments, a signalling for a paging configuration is provided. In some embodiments, a user equipment (UE) may inform a cellular network that the UE is unpageable. The UE may include paging related information indicating that the UE is unpageable into a UE capability signalling message. The paging related information indicating that the UE is unpageable may consist of one or several indicator bits that specifically indicate that the UE is unpageable or that the UE is pageable. The information indicating that the UE is unpageable may also be included in the UE category in the UE capability signalling message that indicates the UE class. The cellular network may understand from the UE category that is signalled by the UE that the UE is unpageable.

Alternatively or additionally, the cellular network may inform a UE that the UE will not be paged by the cellular network. For illustration, in massive deployment of UEs that operate in extended coverage (EC) mode, the cellular network may inform UEs, depending on UE class or UE category, that certain UEs will not receive pages.

If the UE is unpageable or the cellular network informs the UE that the UE will not receive pages, the UE will refrain from listening on the paging channel. Further, the cellular network may refrain from paging the respective user equipment. Battery lifetime of the UE is prolonged and radio access network loads are reduced.

A user equipment according to an embodiment comprises a radio interface operative to transmit or receive a signalling message including paging related information that is indicative of whether the user equipment, UE, is pageable or that is indicative of whether the UE will be paged. The UE comprises an electronic circuit operative to control the radio interface in dependence on the paging related information.

A UE having such a configuration may be operative to not listen for pages at all, if the UE has indicated to the cellular network that the UE is unpageable or if the cellular network has indicated that the cellular network will not page the UE. Battery lifetime of the UE may thereby be prolonged. Further, the load, in the radio access network, may also be reduced.

The radio interface may be operative to transmit at least one UE capability signalling message that includes the paging related information indicating that the UE is unpageable or that the UE is pageable. This allows the UE to inform the cellular network that the UE is unpageable.

The at least one UE capability signalling message may include both a UE category indicator and at least one pageability indicator bit that indicates whether the user equipment is pageable, the at least one pageability indicator bit being an information element different from the UE category indicator. This allows the UE to inform the cellular network that the UE is unpageable using information elements that are independent of the UE category. Different UEs in the same UE category may be selectively defined to be pageable or unpageable.

A UE category indicator included in the at least one UE capability signalling message may be indicative of whether the UE is pageable. This allows the UE to inform the cellular network of the fact that the UE is unpageable using the UE category indicator that must anyway be included in a UE capability signalling message.

The UE category indicator may indicate that the UE is included in a class of unpageable Narrow Band Internet of Things, NB-IoT, devices.

Irrespective of how the UE informs the cellular network of the fact that the UE is unpageable, the unpageable UE may be a UE operating in extended coverage (EC) mode or an unpageable NB-IoT device.

The UE may be configurable by a cellular network so as to be unpageable. This affords network control over whether UEs will listen for pages. The cellular network may selectively cause UEs to refrain from listening for pages, for example if the number of UEs of a certain UE class or the overall number of UEs in a cell exceeds a threshold.

The UE may be operative to receive a signalling message from the cellular network which causes the UE to refrain from listening for paging signals.

The electronic circuit may be operative to control the radio interface such that the UE does not listen on a paging channel if the paging related information indicates that the UE is unpageable or if the paging related information indicates that the UE will not be paged. Battery lifetime of the UE may thereby be prolonged.

The UE that is unpageable or that will not be paged by the cellular network may be a UE operating in extended coverage (EC) mode.

The UE that is unpageable or that will not be paged by the cellular network may be a UE insensitive to high latency on downlink data traffic. A machine type communication (MTC) device is exemplary for such a device.

The UE that is unpageable or that will not be paged by the cellular network may be a Narrow Band Internet of Things (NB-IoT) device.

The UE that is unpageable may be operative to receive downlink user data after the UE initiates mobile originated, MO, traffic or conducts a tracking area update (TAU) procedure. This allows the cellular network node to piggyback on a TAU response, for example, in downlink data transmission.

The UE that is unpageable may be a sensor or a wearable device.

A network node according to an embodiment comprises an interface operative to receive or transmit a signalling message including paging related information that is indicative of whether the user equipment, UE, is pageable or that is indicative of whether the UE will be paged. The network node comprises a processing device operative to control transmission of pages to the UE in dependence on the pageability information.

A network node having such a configuration may be operative to not page a UE, if paging related information received from the UE indicates that the UE is unpageable or if paging related information transmitted by the network node to the UE indicates that the network will not page the UE. Radio access network loads may be reduced.

The processing device of the network node may be operative to process a UE capability signalling message. The UE capability signalling message may include the paging related information that is indicative of whether the UE is pageable.

The processing device of the network node may be operative to determine from at least one pageability indicator bit that is included in the UE capability signalling message that the UE is unpageable.

The processing device of the network node may be operative to determine from a UE category indicator that is included in the UE capability signalling message that the UE is unpageable.

The processing device of the network node may be operative to inform the UE that the UE will not be paged. The processing device of the network node may evaluate any one or any combination of criteria to determine whether the UE is to be paged. For illustration, radio access network loads may be monitored to determine whether the UE is to be paged. Alternatively or additionally, latencies in downlink data transmissions to the UE may be evaluated by the network node to determine whether the UE needs to be paged.

The processing device may be operative to delay a downlink data transmission for a UE that is unpageable until after the UE initiates mobile originated (MO) traffic or conducts a tracking area update (TAU) procedure.

The processing device may be operative to delay a downlink data transmission for a UE that is not paged by the cellular network until after the UE initiates MO traffic or conducts a TAU procedure.

The network node may be a radio access network node. The radio access network node may be an eNodeB. The radio access network node may be a node of a NB-IoT radio access network.

The network node may be a core network node. The core network node may be a MME or SGSN.

A system according to an embodiment comprises the user equipment according to an embodiment and the network node according to an embodiment.

A method of conducting radio communication between a user equipment and a cellular network comprises transmitting a signalling message including paging related information that is indicative of whether the user equipment, UE, is pageable or that is indicative of whether the UE will be paged. The UE does not listen on a paging channel if the pageability information indicates that the UE is unpageable.

Transmitting the signalling message including paging related information may comprise signalling, by the UE, that the UE is unpageable. A non access stratum (NAS) message may be transmitted from the UE to the MME or another core network node to indicate that the UE is unpageable.

Transmitting the signalling message including paging related information may comprise transmitting, by a radio access network of the cellular network, a signalling message indicating that the cellular network will not page the respective UE. The signalling message transmitted by the radio access network may be a TAU response, an attach response, or system information that is broadcast.

The method may comprise refraining, by the UE, from listening on a paging channel if the signalling message indicates that the UE is unpageable or that the cellular network will not page the UE.

The method may comprise refraining, by the cellular network, from paging the UE if the signalling message indicates that the UE is unpageable or that the cellular network will not page the UE.

When the UE is an unpageable NB-IoT device, the radio access network may refrain from paging the UE.

When the UE operates in extended coverage (EC) mode, a radio access network node may determine whether a paging attempt is to be made. If a paging attempt is to be made, only one paging attempt may be made. If the one paging attempt fails, the radio access network node may wait for the UE to initiate MO traffic or to perform a TAU procedure. If no paging attempt is to be made, the radio access network node may wait for the UE to initiate MO traffic or to perform a TAU procedure before a downlink data transmission is performed.

pageable as normal, unpageable, i.e. unable to receive pages, or able to receive pages, but not listening for pages because the network will not send any page for to this device. In any one of the embodiments, the paging related information may be paging to configuration information that specifies a paging configuration. The paging configuration may define whether a UE is

The paging configuration may be defined by the paging related information that is signaled between the UE and the network. The paging configuration may be transmitted from the UE to the network in capability signalling or may be transmitted from the network to the UE when the network informs the UE that it will not page the UE.

Further features of the method according to embodiments and the effects respectively attained thereby correspond to the features and effects described in the context of devices and systems according to embodiments.

Devices, systems and methods according to embodiments allow a UE to refrain from listening for pages and further allow a base station to suppress any transmission of pages to the respective UE.

While some embodiments have been described in the context of machine-type communication (MTC) and NB-IoT devices, the techniques disclosed herein may also be employed for other devices and radio access network techniques.

Exemplary embodiments of the invention will be described with reference to the drawings. While some embodiments will be described in the context of specific fields of application, e.g. in the context of certain communication techniques, the embodiments are not limited to this field of application. The features of the various embodiments may be combined with each other unless specifically stated otherwise.

1 FIG. 1 is a schematic view of a communication systemaccording to an embodiment.

1 10 19 20 30 40 41 30 19 30 20 40 10 40 20 10 30 The communication systemcomprises a cellular network and user equipments (UEs),. Different UEs may be operative for communication with different cellular networks. For illustration, a base stationmay be connected to both a first core networkand a second core networkhaving a cellular network node. The first core networkmay be a legacy LTE core network. The UEmay be operative for communication with the first core networkover the base station. The second core networkmay be a Cellular Internet of Things (CIoT) core network. The UEmay be operative for communication with the second core networkover the base station. The UEmay be operative such that it is incapable of communicating with the first core network.

19 19 The UEmay have a radio interface for communication over an evolved Machine Type Communication (eMTC) radio access network (RAN). The UEmay have a wireless interface for communication over an MTC RAN as described in 3GPP TR 36.888 V12.0.0 (Rel-12) and eMTC for Rel-13.

10 10 10 The UEmay have a radio interface for communication over a Narrow Band Internet of Things (NB-IoT) RAN. The UEmay have a radio interface for communication with a CIoT network as described in 3GPP TR 45.820 and 3GPP TR 23.720. The UEmay have a radio interface for communication with a CIoT network as described in 3GPP TR 45.820 V13.0.0 (Rel-13) and 3GPP TR 23.720 V1.0.0 (Rel-13).

10 19 10 19 As will be described in more detail below, the UEand/or the UEmay be operative such that they are unpageable. For illustration, the UEmay belong to a category of unpageable NB-IoT devices. The UEmay operate in extended coverage mode in which it may be unpageable or in which its pageability may be restricted.

10 19 20 40 30 20 40 30 10 19 20 The UEor the UEmay respectively transmit information indicating that the UE is unpageable to the base stationor the core network,. Alternatively or additionally, the base stationor the core network,may be operative to configure the UEor the UEto be unpageable or may inform the UE that the cellular network will not page the respective UE. If a UE is unpageable or if the cellular network will not page the respective UE, the UE will refrain from listening for pages. There is no need for the UE to wake up to listen on a paging channel. There is no need for the network to transmit pages to the UE. In order to transmit downlink data, an MME, the base stationor other cellular network nodes may wait until after the UE has initiated a TAU procedure or has initiated MO traffic.

10 19 10 19 10 19 10 19 20 While embodiments described in detail hereinbelow will be presented in the context of a base station that receives or transmits paging related information and/or that refrains from paging the UE,under certain conditions, it will be appreciated that the paging may be done by other network nodes. For illustration, an MME may determine, based on a NAS signalling message received from the UE,, that the UE,is unpageable. The MME may refrain from paging the UE,. Similarly, other core network nodes or radio access network nodes may perform the processes that will be described in more detail below in the exemplary context of the base station.

10 19 10 19 10 19 10 19 10 19 10 19 10 19 10 19 10 19 10 19 The UE,and the cellular network may be operative such that paging is reduced compared to legacy discontinuous reception (DRX) schemes when the UE,is unpageable or when the cellular network informs the UE,that it will not be paged. The UE,and cellular network may be operative such that paging is reduced compared to legacy extended DRX (eDRX) schemes when the UE,is unpageable or when the cellular network informs the UE,that it will not be paged. When the UE,is unpageable or when the cellular network informs the UE,that the cellular network will not page the UE,, the UE,may refrain from ever listening for paging signals.

10 19 10 19 10 19 A decision that the cellular network will not page the UE,may be made based on operating mode. For illustration, the UE,may be unpageable in EC mode in which transmissions are repeated many times. Paging of the UE,may be restricted to a single paging attempt in EC mode.

10 19 10 Alternatively or additionally, a decision that the cellular network will not page the UE,may be made based on UE type. For illustration, the UEmay be unpageable when it is included in a category of unpageable NB-IoT devices.

2 FIG. 14 FIG. Paging restrictions may accordingly be implemented in case of EC operation or in case a UE is a NB-IoT device. Various implementations which preclude the UE from being paged or which reduce paging compared to eDRX schemes will be described in more detail with reference totobelow.

2 FIG. 10 10 is a block diagram of a UEaccording to an embodiment. The UEmay be a sensor or a wearable device.

10 11 12 13 11 40 11 30 The UEhas a radio interface unitwhich may include a transmit circuitand a receive circuit. The radio interface unitmay be configured to transmit and receive signals to and from a cellular network which may be a CIoTover a NB-IoT RAN. The radio interface unitmay be configured to transmit and receive signals to and from a cellular network which may be a legacy LTE cellular networkover an evolved Machine-Type-Communication (eMTC) RAN.

11 14 14 Operation of the radio interface unitmay be adjustable under the control of a control circuit. The control circuitmay include one or several processors, controllers, application specific integrated circuits (ASICs), other integrated circuits or combinations of such devices.

14 11 10 14 11 10 10 10 The control circuitmay be configured to control the radio interface unitto transmit a signalling message to the cellular network which indicates that the UEis unpageable. The control circuitmay be configured to control the radio interface unitsuch that it refrains from listening for pages to the UEwhen the signalling message transmitted by the UEto the cellular network indicates that the UEis unpageable.

14 3 10 The control circuitmay be operative to include the paging related information in an attach request or other message. For illustration, the paging related information could use a MS classmarkin the attach request message. The information element may be included in a NAS message between the UEand the MME.

14 11 20 10 14 11 10 10 10 Alternatively or additionally, the control circuitmay evaluate a signalling message received at the radio interface unitfrom the base station. The signalling message may indicate that the UEwill not be paged by the cellular network. In response to receipt of such a signalling message, the control circuitmay be configured to control the radio interface unitsuch that it refrains from listening for pages to the UEwhen the signalling message transmitted to the UEby the cellular network indicates that the UEwill not be paged. The cellular network may control one or several UEs such that those UEs will stop listening for pages. This may be done selectively in massive deployment scenarios where a large number of sensors are deployed within a cell or in dependence on radio access network loads.

10 10 10 The UEmay indicate to the cellular network that it is unpageable if it belongs to a category of unpageable NB-IoT devices. By transmission of a signalling message which includes information on that the UE is unpageable, the cellular network may be informed that downlink transmission is to the UEwill have to be postponed until the UEinitiates MO traffic or performs a TAU procedure, for example.

Information on that the UE is unpageable may be included in UE capability signalling messages. To this end, UE capability signalling messages as defined in 3GPP TS 36.306 V 12.6.0 (Rel-12) or 3GPP TS 24.008 V 13.3.0 (Rel-13) may be modified to include information that indicates that the UE is unpageable. This information may be encoded in various ways. For illustration, a UE category indicator may be defined for a class of NB-IoT devices that are unpageable. Different UE category indicators may be defined for NB-IoT devices that are pageable. Alternatively or additionally, a UE capability signalling message may include at least one pageability indicator bit which indicates whether the UE is pageable or which may indicate that the UE is unpageable.

3 FIG. 50 50 10 is a flowchart of a methodaccording to an embodiment. The methodmay be performed by a UEaccording to an embodiment.

51 At, the UE may transmit a UE capability signalling message that includes paging related information indicating that the UE is unpageable.

52 11 At, the UE may operate without listening for pages. The radio interface unitmay be controlled such that the UE does not listen on the paging channel. Power consumption may be reduced thereby.

41 In order to receive downlink traffic, the UE may initiate MO traffic or may perform a TAU procedure. The cellular network, e.g. a MME, may wait for the UE to initiate MO traffic or perform a TAU procedure until downlink data is piggybacking on to the signals transmitted to the UE.

The time intervals between successive periods in which the UE may receive downlink transmissions may be much longer than the time interval between successive intervals in which the UE performs uplink data transmission.

4 FIG. is a signalling diagram that illustrates UE capability signalling to indicate that the UE is unpageable.

61 62 63 The UE and cellular network may perform an RRC setup. The UE and cellular network may execute authentication procedures. The UE and cellular network may perform NAS security procedures.

30 64 10 The cellular networkmay transmit a UE capability enquiryon to the UE.

64 65 10 In response to receiving the UE capability enquiry, the UE may transmit a UE capability signalling messagethat includes information that the UEis unpageable.

In continued operation of the UE, the UE will never listen for pages from the cellular network.

5 FIG. 70 10 70 71 70 72 72 70 72 10 shows a UE capability signalling messagethat may be transmitted by the UEaccording to an embodiment. The UE capability signalling messagemay include at least one and preferably several UE category indicator bits. The UE capability signalling messageincludes one or several UE pageability indicator bit(s). The UE pageability indicator bit(s)may be set to a first value that indicates that the UE is unpageable. In response to receiving a UE pageability signalling messagein which the UE pageability indicator bit(s)are set to a first value that indicates that the UE is unpageable, the cellular network may stop paging the UEor may refrain from ever starting paging.

72 70 72 10 10 10 10 The UE pageability indicator bit(s)may be set to a second value that indicates that the UE is pageable. In response to receiving a UE pageability signalling messagein which the UE pageability indicator bit(s)are set to a second value that indicates that the UE is pageable, the cellular network may page the UEin any one of a variety of techniques. Those techniques may include techniques in which the cellular network decides to restrict paging of the UE, which then in turn causes the UEto refrain from listening for pages even when the UEis pageable.

10 For illustration, the MME of the cellular network may page the UEaccording to a conventional DRX scheme or an extended DRX (eDRX) scheme.

10 10 10 10 10 10 10 The cellular network may also inform the UE, even when the UEis pageable, that the cellular network does not intend to page the UEor that other paging restrictions will apply. For example, the cellular network may inform the UEthat the cellular network will not page the UE. In response to receipt of such information from the cellular network, the UEmay terminate listening for pages. Paging restrictions may be invoked by the cellular network when the UEoperates in EC mode, for example, or is an MTC device.

6 FIG. 75 10 75 76 76 75 76 10 10 shows a UE capability signalling messagethat may be transmitted by the UEaccording to an embodiment. The UE capability signalling messagemay include several UE category indicator bits. The UE category indicator bitsmay be set to a first value that indicates that the UE is an unpageable NB-IoT device. In response to receiving a UE pageability signalling messagein which the UE category indicator bitsmay be set to a first value that indicates that the UE is an unpageable NB-IoT device, the cellular network may stop paging the UEor may refrain from ever starting paging the UE.

76 76 76 10 5 FIG. The UE category indicator bitsmay be set to a second value that indicates that the UE is a pageable NB-IoT device. In response to receiving a UE pageability signalling messagein which the UE category indicator bitsare set to a second value that indicates that the UE is a pageable NB-IoT device, the cellular network may page the UEin any one of a variety of techniques as described with reference toabove.

7 FIG. is a signalling diagram which illustrates operation of a UE that is an unpageable NB-IoT device.

81 81 82 83 82 83 83 83 82 An attach procedureis carried out for the user equipment to attach to the CIoT network. NAS signalling may be performed in the attach procedure, e.g. to inform the cellular network of UE pageability. In the attach procedure the amount of UL data may be announced e.g. using a buffer status report, BSR. The CIoT may grant the UE UL resources to complete stepand, for illustration if the BSR indicates a buffer level exceeding a threshold. After RRC connection establishment, an initial UE messagemay be transmitted. The messagemay include encryption data and, optionally, information on whether an acknowledgement is required. The messagemay include a NAS PDU user data transmission as part of the RRC connection establishment in step.

81 82 The UE which is a NB-IoT device may transmit pageability information in the attach procedureor during the RRC connection establishment. This may be done if the UE would like to change its pageability without performing a TAU. Normal capability signalling may be done at initial attach/network registration. Some UE parameters may be updated with TAU procedures.

It will be appreciated that a UE which is an unpageable NB-IoT device may have reduced signalling before data transmission, which reduces the number of messages that need to be sent or received by the user equipment before the user data can be transmitted or received compared to eMTC or legacy LTE procedures, reduces the complexity and the associated power consumption of the user equipment. Due to the fact that the unpageable NB-IoT device does not need to listen for pages, power consumption may be reduced further.

In addition or as an alternative to UE capability signalling that indicates that the UE is unpageable, the cellular network may also inform the UE that the cellular network will not page the UE. In response to such a signalling message or broadcast message, the UE may stop listening on a paging channel or may refrain from ever starting listening for pages.

8 FIG. 10 91 91 10 91 10 92 10 10 10 is a signalling diagram in a communication system according to an embodiment. The UEmay receive an attach responsefrom the cellular network. The attach responsemay include paging related information that indicates that the cellular network will not page the UE. Alternatively, the paging related information may indicate that other paging restrictions apply. In response to receiving the attach response, the UEwill refrain from listening on a paging channel at. During ongoing operation of the UE, the UEmay be operative such that the UEdoes not listen for pages from the cellular network.

9 FIG. 10 93 10 94 94 10 94 10 92 10 10 10 is a signalling diagram in a communication system according to an embodiment. The UEmay transmit a TAU request. The UEmay receive a TAU response. The TAU responsemay include paging related information that indicates that the cellular network will not page the UE. Alternatively, the paging related information may indicate that other paging restrictions apply. In response to receiving the TAU response, the UEwill refrain from listening on a paging channel at. During ongoing operation of the UE, the UEmay be operative such that the UEdoes not listen for pages from the cellular network.

10 FIG. 10 95 95 95 10 10 95 10 92 10 10 10 is a signalling diagram in a communication system according to an embodiment. The UEmay receive system information. The system informationmay include one or several system information blocks. The system informationmay include paging related information that indicates that the cellular network will not page the UEor that the cellular network will not page any UE having certain UE class(es) to which the UEbelongs. Alternatively, the paging related information may indicate that other paging restrictions apply. In response to receiving the system information, the UEwill refrain from listening on a paging channel at. During ongoing operation of the UE, the UEmay be operative such that the UEdoes not listen for pages from the cellular network.

11 FIG. 20 20 20 30 20 40 is a functional block diagram of a base stationaccording to an embodiment. The base stationmay be an eNodeB. The base stationmay have a first core network interface for coupling to a first core network. The base stationmay have a second core network interface for coupling to a second core networkwhich may be a CIoT CN.

20 21 21 22 23 The base stationhas at least one radio interface unit. The at least one radio interface unitincludes a transmit circuitand a receive circuit.

20 24 21 21 20 10 10 10 22 21 10 The base stationincludes a processing deviceoperative coupled to the at least one radio interface unitto control the at least one radio interface unit. The base stationmay be operative such that, in response to receipt of a capability signalling message from the UEthat indicates that the UEis unpageable, the UEwill not receive any pages. There transmit circuitof the radio interface unitmay be controlled such that no pages are transmitted for the UEthat is unpageable.

20 24 10 25 10 10 20 10 20 41 The base stationmay be operative such that the processing devicecauses downlink data directed to an unpageable UEto be buffered in a storage device. The downlink data may be transmitted on to the unpageable UEonly when the unpageable UEinitiates MO traffic or performs a TAU procedure. While the base stationmay store the downlink data directed to the unpageable UEin the base station, the downlink data may also be stored in other cellular network nodes such as the MME.

It will be appreciated that with massive deployment of sensors or wearable devices that mainly or intended to report measurement results to a cellular network, there is an increasing number of UEs that can accommodate long latency for downlink transmissions. NB-IoT devices or eMTC devices are exemplary for UEs that can accommodate long latency for downlink transmissions and that may therefore not need to be paged.

24 22 19 19 24 22 19 The processing devicemay also be operative to control the transmit circuitsuch as to inform a pageable UEthat the cellular network does not intend to page the UE. The processing devicemay control the transmit circuitto transmit information indicating that the cellular network does not intend to page the UEover the RAN.

20 19 19 19 22 21 19 The base stationmay be operative such that, after informing the UEthat indicates that cellular network will not page the UE, the UEwill not receive any pages. The transmit circuitof the radio interface unitmay be controlled such that no pages are transmitted for the UEwhich is not to be paged.

20 24 19 25 19 19 20 19 20 41 The base stationmay be operative such that the processing devicecauses downlink data directed to a UEthat will not be paged to be buffered in the storage device. The downlink data may be transmitted on to the UEthat will not be paged only when the UEinitiates MO traffic or performs a TAU procedure. While the base stationmay store the downlink data directed to the UEin the base station, the downlink data may also be stored in other cellular network nodes such as the MMEor serving gateway (SGW) or PDN gateway (PGW) or SMS server.

20 11 FIG. While a base stationhas been explained with reference to, it will be appreciated that other cellular network nodes, including core network nodes, may be operative to determine whether a UE is to be paged. For illustration, an MME in the CN may be operative to evaluate pageability information provided by a UE to the cellular network. The MME may refrain from paging the UE if the pageability information indicates that the UE is unpageable.

Other paging restrictions may alternatively or additionally be used. For illustration, only one paging attempt may be performed by the cellular network. The cellular network may use information about a last known coverage extension (CE) level and cell in the one paging attempt. If the UE does not respond to the one page attempt, the cellular network will wait for the UE to initiate MO traffic or conduct a TAU procedure. The MME could then piggy back its information.

20 For UEs operating in EC mode, the base stationmay selectively determine whether the cellular network will refrain from paging the respective UE or whether only one paging attempt will be used.

12 FIG. 100 100 20 41 is a flowchart of a methodaccording to an embodiment. The methodmay be performed by a base stationor a cellular network node, such as an MME.

101 At, downlink (DL) data is to be transmitted to a UE.

102 103 At, it is determined whether the UE is unpageable or whether the UE was otherwise instructed to not listen for pages on the paging channel. If the UE is pageable and if the UE was not informed that the cellular network will refrain from paging the UE, the method proceeds to.

103 104 At, the cellular network pages the UE. At, the DL data is transmitted to the UE.

105 20 At, if it is determined that the UE is unpageable or that the UE was informed that the cellular network will refrain from paging the UE, the DL data may be stored. The DL data may be stored selectively, depending on the data. The DL data may be stored in a storage device of the base stationor of another cellular network node.

106 20 106 At, it is determined whether the UE initiates a MO data transmission or performs a TAU procedure. The base stationor other cellular network node may continue the monitoring at stepuntil after the UE has initiated a MO data transmission or performed a TAU procedure.

107 At, after the UE has initiated a MO data transmission or performed a TAU procedure, the DL data will be transmitted to the UE. The DL data transmission may be piggy backed on a TAU procedure or MO traffic utilizing the available RRC connection.

13 FIG. Paging restrictions may be employed selectively if a UE operates in EC mode or if a UE is a NB-IoT device. This will be explained in more detail with reference to.

13 FIG. 110 110 20 41 is a flowchart of a methodaccording to an embodiment. The methodmay be performed by a base stationor a cellular network node, such as an MME.

111 At, downlink (DL) data is to be transmitted to a UE.

112 113 114 113 114 At, it is determined whether the UE to which the DL data is to be transmitted operates in EC mode. If the UE does not operate in EC mode, the method proceeds to stepsand. At, the cellular network pages the UE. At, the DL data is transmitted to the UE.

115 112 102 12 FIG. At, if it was determined at stepthat the UE is in EC mode, it is determined whether the UE can be paged. This may be implemented using decision logic as explained with reference to stepof, for example. Determining whether the UE can be paged may involve determining whether the UE has indicated in capability signalling that the UE is an unpageable NB-IoT device and whether the cellular network has indicated that it does not intend to page the UE.

116 If it is determined that the UE can be paged, the method may proceed to.

116 At, the UE operating in EC mode may be paged just once. The base station may use information about the last known CE level and cell when making the just one paging attempt.

117 118 At, it is determined whether the paging attempt is successful. If the paging attempt has been successful, the method proceeds toand the DL data is transmitted to the UE.

119 116 20 119 At, if the UE cannot be paged or if the paging attempt atwas unsuccessful, it is determined whether the UE initiates a MO data transmission or performs a TAU procedure. The base stationor other cellular network node may continue the monitoring at stepuntil the UE has initiated a MO data transmission or performed a TAU procedure. The network may store the data, if required or possible, until the data may be transmitted to the UE.

120 At, after the UE has initiated a MO data transmission or performed a TAU procedure, the DL data will be transmitted to the UE. The DL data transmission may be piggy backed on a TAU procedure or MO traffic utilizing the available RRC connection.

14 FIG. The paging restrictions which cause the UE to refrain from listening for pages or which limit paging to just one paging attempt may be employed when the coverage of a cell is to be extended, for example for EC mode in which transmissions are repeated several times are for NB-IoT operation. The extension of coverage is illustrated in.

14 FIG. 131 132 133 10 illustrates the extended coverage radius modes in which a user equipment may refrain from listening for pages or in which the cellular network may inform the UE that it does not intend to page the UE. The normal coverage in legacy LTE is defined by a first coverage radius. The eMTC device in EC mode has a second, extended coverage. NB-IoT that may have a certain coverage extension (CE) level may provide a third, even further extended coverage. It will be appreciated that an eMTC device or NB-IoT device may also be combine the different EC. A UE, which may be a sensor or a wearable device operative in accordance with NB-IoT, may refrain from listening for pages from the cellular network.

Various effects are attained by the devices, methods and systems according to embodiments. For illustration, user equipment battery lifetime may be prolonged. Radio access network loads may be reduced. This is attained by implementing paging restrictions in which paging is reduced even further compared to eDRX, and which causes the UE to refrain from listening for pages, for example. The paging restrictions may cause the cellular network to refrain from paging one or several UEs.

pageable as normal, unpageable, i.e. unable to receive pages, or able to receive pages, but not listening for pages because the network will not send any page for to this device. In any one of the embodiments, the paging related information may be paging configuration information that specifies a paging configuration. The paging to configuration may define whether a UE is

The paging configuration may be defined by the paging related information that is signaled between the UE and the network. The paging configuration may be transmitted from the UE to the network in capability signalling or may be transmitted from the network to the UE when the network informs the UE that it will not page the UE.

While exemplary embodiments have been described with reference to the drawings, modifications may be implemented in other embodiments. For illustration, while embodiments have been described in the context of exemplary cellular networks and radio access networks, the techniques discussed herein are applicable to a wide variety of other cellular networks. For further illustration, while exemplary operation modes and device classes have been described in which paging restrictions may apply, other modes or UE classes may also be subject to paging restrictions.

While the user equipment may be a sensor or a wearable device, the techniques discussed herein may also be used in conjunction with other user equipments.

Although the invention has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the following claims.