WO2021083940A1

WO2021083940A1 - Beam indication for paging

Info

Publication number: WO2021083940A1
Application number: PCT/EP2020/080250
Authority: WO
Inventors: Rapeepat Ratasuk; Srinivasan Selvaganapathy; Jussi-Pekka Koskinen; Nitin MANGALVEDHE
Original assignee: Nokia Technologies Oy
Priority date: 2019-10-29
Filing date: 2020-10-28
Publication date: 2021-05-06

Abstract

It is provided a method comprising: transmitting two or more first paging wakeup signals through two or more beams, the two or more first paging wakeup signals indicating a paging message to be transmitted; receiving a preamble associated with one of the two or more beams; and transmitting the paging message using the one of the two or more beams.

Description

Beam indication for paging

Field of the invention The present invention relates to paging, in particular to paging in the context of beam-based operation.

Abbreviations

Background of the invention

In Rel-17, it is planned to address use cases that cannot be met by NR eMBB, URLLC or eMTC/NB-loT. One or more of the following requirements should be supported:

• Higher data rate & reliability and lower latency than eMTC & NB-loT

• Lower cost/complexity and longer battery life than NR eMBB

• Wider coverage than eMBB.

Specifically, one or more of the following objectives and use cases will be addressed:

• Moderate data rates up to [100] Mbps to support e.g. live video feed, visual production control, process automation

• Moderate latency of around [10-30] ms to support e.g. remote drone operation, cooperative farm machinery, time-critical sensing and feedback, remote vehicle operation

• Low complexity device with module cost comparable to LTE

• Coverage enhancement of [10-15] dB compared to eMBB

• Low power consumption with battery life [2-4] times longer than eMBB

• Positioning accuracy of [30 cm - 1 m] to support e.g. indoor asset tracking, coordinated vehicle control, remote monitoring

Both frequency range FR1 (450-7225 MHz) and FR2 (24250 - 52600 MHz) may be supported. In FR2, beam-based operation (i.e. using narrow beams to communicate with UE) is the typical operation mode. This means that, in FR2, NR uses beam-based operation with many beams per cell. Each beam covers only a fraction of the cell coverage area (e.g. up to 64 SSBs, each associated with a beam, may be configured in a cell). This is illustrated in Fig. 1. In addition, RF-beamforming (or analog beamforming) is likely to be used in FR2 which means that UEs are typically TDM instead of FDM (i.e., the entire BW is given to one UE at a time) unless the gNB finds two UEs to schedule using the same beam.

Summary of the invention

It is an object of the present invention to improve the prior art. According to a first aspect of the invention, there is provided an apparatus comprising: first means for transmitting two or more first paging wakeup signals through two or more beams, the two or more first paging wakeup signals indicating a paging message to be transmitted; means for receiving a preamble associated with one of the two or more beams; and second means for transmitting the paging message using the one of the two or more beams.

According to a second aspect of the invention, there is provided an apparatus comprising: means for monitoring, by using two or more beams, a paging wakeup signal indicating a paging message to be transmitted; first means for receiving the paging wakeup signal on one of the two or more beams; means for transmitting a preamble in response to the paging wakeup signal, wherein the preamble is associated with one of the two or more beams; and second means for receiving the paging message based on the one of the two or more beams.

According to a third aspect of the invention, there is provided a method comprising: transmitting two or more first paging wakeup signals through two or more beams, the two or more first paging wakeup signals indicating a paging message to be transmitted; receiving a preamble associated with one of the two or more beams; and transmitting the paging message using the one of the two or more beams.

According to a fourth aspect of the invention, there is provided a method comprising: monitoring, by using two or more beams, a paging wakeup signal indicating a paging message to be transmitted; receiving the paging wakeup signal on one of the two or more beams; transmitting a preamble in response to the paging wakeup signal, wherein the preamble is associated with one of the two or more beams; and receiving the paging message based on the one of the two or more beams.

Each of the methods of the third and fourth aspects may be a method of paging.

According to a fifth aspect of the invention, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any of the third and fourth aspects. The computer program product may be embodied as a computer-readable medium or directly loadable into a computer. According to some embodiments of the invention, at least one of the following advantages may be achieved:

• Signaling overhead may be reduced;

• Latency may be reduced;

• Robustness of paging may be improved.

It is to be understood that any of the above modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives.

Brief description of the drawings

Further details, features, objects, and advantages are apparent from the following detailed description of the preferred embodiments of the present invention which is to be taken in conjunction with the appended drawings, wherein:

Fig. 1 illustrates beam-based operation;

Fig. 2 illustrates paging for beam-based operation according to the prior art;

Fig. 3 illustrates WUS in beam-based operation according to some example embodiments of the invention;

Fig. 4 shows a message flow according to some example embodiments of the invention; Fig. 5 shows an apparatus according to an embodiment of the invention;

Fig. 6 shows a method according to an embodiment of the invention;

Fig. 7 shows an apparatus according to an embodiment of the invention;

Fig. 8 shows a method according to an embodiment of the invention;

Fig. 9 shows an apparatus according to an embodiment of the invention;

Fig. 10 shows a method according to an embodiment of the invention;

Fig. 11 shows an apparatus according to an embodiment of the invention;

Fig. 12 shows a method according to an embodiment of the invention; and Fig. 13 shows an apparatus according to an embodiment of the invention.

Detailed description of certain embodiments

Herein below, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein the features of the embodiments can be freely combined with each other unless otherwise described. However, it is to be expressly understood that the description of certain embodiments is given by way of example only, and that it is by no way intended to be understood as limiting the invention to the disclosed details.

Moreover, it is to be understood that the apparatus is configured to perform the corresponding method, although in some cases only the apparatus or only the method are described.

For beam-based operation, when a UE is being paged, the gNB does not know which beam to use for the UE since the UE is in idle mode and not reporting beam information to the gNB. Conventionally, the gNB may sequentially page the UE using 1 beam at a time (lower overhead but very high latency), or gNB may page the UE using all beams (low latency but very high overhead). In addition, when multiple UEs are being paged in the same PO, the PDSCH contains a common paging message for all UEs as gNB does not know which beam each UE belongs to. A paging message is transmitted on the PDSCH that is scheduled by a Downlink Control Information on the PDCCH.

One of these ways of conventional paging for beam-based operation is illustrated in Fig. 2. There is one pair of PDCCH and PDSCH for each of the beams 1 to N. N is the number of beams. Each PDSCH comprises a paging message (for simplicity, only indicated for PDSCH of beam 2). It is seen that the paging message, for possibly multiple UEs, must be sent N times. For example, each beam may require 1 subframe or slot to transmit the scheduling control information and paging message. In most cases, only 1 or 2 UEs are being paged within each paging occasion. The overhead for paging is therefore very high in this conventional example of beam-based operation. This operation is described in 3GPP TS 38.304, section 7.1.

In beam-based or multi-beam operations, the UE can assume that the same paging message is repeated in all transmitted beams and, thus, the selection of the beam(s) for the reception of the paging message is up to UE implementation. The paging message is same for both RAN initiated paging and CN initiated paging.

Some example embodiments of the invention provide a method to overcome this high paging overhead when using beam-based operation.

Some example embodiments of the invention provide a very short paging wakeup and indicator signal (hereinafter also denoted as “wakeup signal”, WUS). When there is a paging message to be sent, gNB may send this signal on all the beams before the actual paging message. WUS may carry a few bit(s) of information, such as 1 bit, 2 bits, 3 bits, or 4 bits of information.

In advance, gNB also indicates one or more PRACH resources (i.e., each or a combination of a preamble and a PRACH occasion) to be transmitted by UE in response to the WUS. A PRACH occasion is a combination of a PRACH time (time window) and a PRACH frequency (frequency band) on which the preamble may be transmitted. gNB may indicate the PRACH resource via higher-layer broadcast signaling (e.g. SIB1) or dedicated signaling e.g. RRCReconfiguration. The PRACH resource actually transmitted by the UE depends at least on the beam on which the UE receives the WUS.

The paging wakeup and indicator signal may be cell-specific (i.e., the WUS in the cell is independent from the UE to be paged), UE group-specific (i.e., related to a group of UEs), or U E-specific.

In some example embodiments of the invention, from the combination of WUS sent by gNB and PRACH resource transmitted by UE (and received by gNB), gNB can unambiguously derive the beam on which the UE to be paged is located. For example:

• if WUS is UE specific, the actually transmitted PRACH resource may encode at least the beam on which UE received WUS. It may or may not need to encode further information;

• If WUS is cell-specific, the actually transmitted PRACH resource may encode at least the UE ID and the beam on which UE received WUS. It may or may not need to encode further information;

• If WUS is UE group-specific, the actually transmitted PRACH resource may encode at least an indication which group member is the UE and the beam on which UE received WUS. It may or may not need to encode further information.

That is, the more information is carried by WUS, the less information may be carried by the PRACH resource (and vice versa).

In some example embodiments of the invention, gNB may not derive unambiguously the beam on which the UE is located but may restrict the number of beams on which the UE is located. For example, if WUS is UE group-specific and all the members (UEs) of the group reply by a preamble of the same set of resources associated to beams, gNB may get information that the UE to be paged is located on one of the beams on which any member of the group is located. E.g., if there are 4 group members, gNB may derive from the received resources up to 4 potential beams (depending on if some of the UEs are on the same beam, there might be less than 4 potential beams) on which the UE to be paged is located. As another example, in a set of resources associated to beams, several beams may be associated to a same resource (a kind of a “group of beams”). In this case, gNB only knows that the UE to be paged is in one of the beams of the group.

In some example embodiments, gNB may further optimize the beams to be selected for actual paging if it knows the last known beam information from CN (similar to last connected cell). In this case, gNB may select a set of beams surrounding the last known beam for transmitting WUS instead of transmitting WUS in all the beams of the cell.

Upon reception of an appropriate WUS (i.e. a WUS that is associated to the respective UE either directly (in case of U E-specific WUS) or indirectly (in case of UE group-specific WUS or cell-specific WUS)), UE will transmit a preamble at the PRACH occasion (using reserved preamble index) associated with the beam on which the wakeup signal was received. Typically, the beam is tied to SSB such that UE may derive the beam information or index from the SSB. Instead of or in addition to SSB, the beam may be associated with other transmissions, e.g. reference signals, synchronization signals, tracking signals, control channel, or data channel. A separate preamble index may be reserved for the wakeup signal received on each cell (for group-specific and U E-specific signals) in case the PRACH occasion is common to multiple WUSs.

In an example embodiment, if all the stationary UE within the cell are known already and also the UE mapping to paging occasion is known, and if the number of UEs per PO are less than or equal to the number of WUSs, then a dedicated WUS may be assigned for each UE. In this case, dedicated WUS given by e.g. a dedicated sequence can be assigned to each UE. Here there will not be any issue related to multiple UEs sending preambles.

In some example embodiments, an independent PRACH configuration may be used for response to WUS. In this case, a separate PRACH preamble may be reserved for each WUS (i.e. for the transmission of the same WUS on each beam by gNB and reception of the same WUS on each beam by UE). All PRACH preambles share a common PRACH occasion associated with the PO.

In another example embodiment, a PRACH preamble is reserved for multiple WUSs. I.e., the PRACH preamble is common to the multiple WUSs (i.e. for the transmission of the same WUS on plural beams by gNB and reception of the same WUS on one of the plural beams by UE). In this case, the gNB may distinguish the respective beam from the PRACH occasion because a separate PRACH occasion is configured for reception of WUS on each beam. In this case, the reserved preamble is common to all the SSBs (beams), and many UEs may transmit using the same preamble. This is not a problem as gNB only needs to detect the presence of the preamble and the respective PRACH occasion.

If the WUS is not UE specific, more than one UE may attempt to respond. So multiple UEs may send the preamble. In this case, o Multiple group WUS can be used to limit the number of UEs that are signaled. The WUS sequences for different groups may be multiplexed in the code, frequency, or time domains. The sequences may be longer in the case of code multiplexing. o Response from a large number of UEs can be avoided by allowing UEs to randomly decide on sending the preamble in response to the WUS. Alternatively, some specific sub-groups within a group (e.g., based on UE ID) are always configured to send the preamble. o In case there are multiple UEs to be paged in the paging occasion, the preamble in response to the WUS may be transmitted on different beams. If the actual UE to be paged did not send the preamble, then there will not be any response.

The random decision for sending the preamble in response to the WUS at a UE may also consider the past paging reception history on this paging occasion. For example, a UE that has a low probability of being paged can be prevented from sending a preamble, which may otherwise lead to false wake up and reception of paging at all the UEs on that paging occasion.

Upon detection of the PRACH preamble(s), the gNB knows which (potential) beams have UE(s) that are monitoring whether the paging message is received. The gNB then transmits a paging message using the appropriate one or more beams. In some example embodiments, the paging message in each beam may be UE-specific instead of common or beam-specific if dedicated PRACH preambles are allocated per UE. This saves overhead significantly.

In some example embodiments, after the UE has sent the preamble on the PRACH the UE starts monitoring the paging message on the beam associated with the beam the WUS was received. In other example embodiments, the UE in IDLE or INACTIVE state permanently monitors the PDSCH for a paging message. In case the gNB does not detect any preamble in response to the WUS, there are two options: o Option 1 : Paging is sent in all beams: This is applicable if the preamble transmission from UE is selective, i.e. , all UEs that receive the WUS do not send a preamble response (e.g., when it is random, based on beam or UE- ID). o Option 2: No paging is sent: This is applicable if all the UEs are expected to send a preamble in response to receiving the WUS. That is, in this case, it may be concluded that a UE is not within the cell.

Fig. 3 illustrates the WUS for beam-based operation. The wake-up signal indicates an upcoming paging message. The UE then transmits a preamble on the PRACH to tell the gNB of the best or preferred beam on which to transmit the PDCCH + PDSCH for paging.

In some example embodiments, more than one PRACH resource (combinations of preamble(s) and PRACH occasion(s)) may be associated to each beam and to each UE. Thus, the UE may transmit additional information to gNB prior to paging. For example, UE may transmit a first one of these PRACH resources if it is substantially static such that the paging message will reach the UE in the same beam as WUS. UE may transmit the second of these PRACH resources if the UE is moving fast such that the paging message might potentially reach the UE in a different beam than that on which the UE received WUS. Dependent on the received PRACH resource, gNB may transmit the paging message in one beam only or in a bundle of beams around this one beam.

A key advantage of a method according to some example embodiments of the invention is that it significantly reduces the overhead associated with paging in beam-based operation. This is because the WUS itself requires the use of significantly fewer resources for transmission than the paging message. For instance, if a cell is using 16 beams and only 1 UE is being paged, the gNB transmits the WUS on all the beams (e.g., using only 2 subframes), but it would have to send the paging message in only 1 subframe instead of 16 subframes. In addition, the gNB can also estimate the SINR from the UE’s PRACH transmission (e.g. if the wake-up signal is UE specific). This allows the gNB to optimize the MCS of the paging message. For instance, for UE in good condition, gNB can transmit the paging message using higher MCS and smaller number of resource blocks. This minimizes the overhead of the transmission and leaves more resource blocks for data transmission to other UEs. Fig. 4 illustrates a message flow according to some example embodiments of the invention. In Fig. 4, the UE is in an RRC idle status or an INACTIVE state (step 1).

The gNB transmits a system information block (SIB) including a first configuration information element for a wakeup and indicator signal (WUS) (step 2). The WUS configuration may include, for example, the number of resources for WUS transmission, the number of UE groups associated with each WUS resource, the relative time-frequency locations for the WUS resources, and information related to gaps between the WUS resources and the paging occasion. The gNB transmits a SIB including a second configuration information element for PRACH resources to be used for responding to the WUS (step 3). The PRACH configuration may include, for example, the time-frequency locations for PRACH transmission and the set of preambles reserved for WUS response. In some example embodiments, the time-frequency location or the index of the preamble selected for PRACH transmission may indicate the index of the beam via which the WUS was received by the UE and/or the WUS group to which the UE belongs. Each of the SIBs may be transmitted periodically (and independently) and/or they may be transmitted trigger based in case the first and/or the second configuration lEs are needed to be transmitted.

Alternatively, the configuration information element for the WUS and the configuration information element for the PRACH resources may be transmitted through the same SIB. In some example embodiments, some or all of the configuration parameters may be indicated to the UE via RRC signaling.

Then, gNB receives a request from a network entity (e.g., a core network) to page the UE, or the gNB decides to page the UE (unshown). Thus, in step 4, the gNB sends the WUS based on the first configuration IE on all beams of the cell (e.g. 64 beams) that the gNB manages.

The UE monitors whether the WUS is received by using all of the beams managed by the UE and receives the WUS based on the first configuration IE by using one of the beams. For example, it is assumed that the UE receives the WUS on beam 7 (step 5).

In response to the received WUS, the UE transmits a PRACH preamble (or, indicating message) based on the second configuration IE. In this case, the PRACH preamble is associated with the beam 7. Alternatively, the PRACH preamble includes a preamble index associated with the beam 7, or the PRACH occasion is associated to the beam 7 (step 6). Also, in some example embodiments, a combination of two or three of PRACH preamble, PRACH preamble index, and PRACH occasion is associated with beam 7.

After transmitting the PRACH preamble, the UE starts to monitor whether the paging message is received (step 7). In some example embodiments, UE may continue monitoring whether the paging message is received. In some example embodiments, UE may monitor whether the paging message is received using the beam 7 only.

If the gNB receives the PRACH preamble from the UE, the gNB is able to know which beam is proper to transmit a paging message. That is, the gNB understands from the received PRACH preamble (preamble index, PRACH occasion) that the UE is on beam 7. Accordingly, the gNB transmits the paging message to the UE on beam 7 (step 8) and the gNB does not transmit the paging message on the other beams (in this example: not on beams 1 to 6 and 8 to 64).

After receiving the paging message from the gNB by using the beam 7, the UE performs a RRC connection establishment procedure with the gNB in order to enter into a RRC connected mode (step 9).

Fig. 5 shows an apparatus according to an embodiment of the invention. The apparatus may be a cell (embodied by a base station such as a gNB, eNB etc.), or an element thereof. Fig. 6 shows a method according to an embodiment of the invention. The apparatus according to Fig. 5 may perform the method of Fig. 6 but is not limited to this method. The method of Fig. 6 may be performed by the apparatus of Fig. 5 but is not limited to being performed by this apparatus.

The apparatus comprises means for monitoring 10, means for waking 20, means for detecting 30, and means for inhibiting 40. The means for monitoring 10, means for waking 20, means for detecting 30, and means for inhibiting 40 may be a monitoring means, waking means, detecting means, and inhibiting means, respectively. The means for monitoring 10, means for waking 20, means for detecting 30, and means for inhibiting 40 may be a monitor, waking device, detector, and inhibitor, respectively. The means for monitoring 10, means for waking 20, means for detecting 30, and means for inhibiting 40 may be a monitoring processor, waking processor, detecting processor, and inhibiting processor, respectively.

The means for monitoring 10 monitors whether a paging message is to be transmitted to a first terminal in a cell, i.e. , if the first terminal (UE) is to be paged in the cell (S10). If the first terminal is to be paged in the cell (S10 = yes), the means for waking 20 instructs a transmitting device to transmit a first wakeup signal using two or more beams of a cell (S20). The means for waking 20 instructs that the transmitting of the first wakeup signal is performed prior to the transmitting of the paging message. The first wakeup signal comprises fewer bits or fewer radio resources than the paging message. For example, the first wakeup signal may carry 3 bits of information indicating one of eight UE groups whereas a paging message may carry many more information bits of information including the ID of the UE being paged. In another example, the wakeup signal may occupy a fraction of the time-frequency radio resources required to transmit the paging message.

The means for detecting 30 detects if a first resource is received in response to the first wakeup signal (S30). According to stored associations, the first resource is associated with a first beam of the one or more beams. In this context, a resource is defined as a preamble comprising a preamble index and an occasion to transmit the preamble The association to the first beam may be via the preamble, the preamble index, the occasion, or a combination thereof.

If the first resource is received (S30 = yes), the inhibiting means 40 inhibits the transmitting device from transmitting the paging message in a second beam of the two or more beams (S40). The second beam is different from the first beam, i.e., different from the beam to which the received resource is associated. In some example embodiments, the inhibiting means 40 additionally instructs the transmitting device to transmit the paging message using only a subset of the two or more beams, wherein the subset comprises the first beam and does not comprise the second beam. In such example embodiments, the means for inhibiting 40 may be actually a means for paging. The subset may comprise only the first beam, or it may comprise more beams than only the first beam.

The apparatus may further comprise means for informing configured to inform the first terminal which resource among a first set of plural resources including the first resource is associated with which one of the plural beams. Each of the resources of the first set may comprise a respective combination of a respective preamble and a respective occasion on which the terminal transmits the respective preamble.

The means for waking may be configured to instruct the transmitting device to transmit a second wakeup signal using the plural beams of the cell if a second terminal is to be paged; and the means for informing may be configured to inform the second terminal which resource among the first set of plural resources including the first resource is associated with which one of the plural beams; wherein the second terminal may be different from the first terminal; the second wakeup signal may be different from the first wakeup signal; and the second wakeup signal may comprise less radio resources than a paging message to be transmitted to the second terminal.

The means for informing may be configured to inform a third terminal different from the first terminal which resource among a second set of plural resources is associated with which one of the two or more beams, wherein each of the resources of the first set may be different from each of the resources of the second set; and the means for waking may be configured to instruct the transmitting device to transmit the first wakeup signal using the one or more beams of the cell if the third terminal is to be paged.

The apparatus may further comprise means for estimating configured to estimate a reception quality of the received resource; means for selecting configured to select a modulation and coding scheme for the paging message based on the estimated reception quality; means for instructing configured to instruct the transmitting device to modulate and code the paging message with the selected modulation and coding scheme.

Fig. 7 shows an apparatus according to an embodiment of the invention. The apparatus may be a terminal such as a UE, an loT device, etc., or an element thereof. Fig. 8 shows a method according to an embodiment of the invention. The apparatus according to Fig. 7 may perform the method of Fig. 8 but is not limited to this method. The method of Fig. 8 may be performed by the apparatus of Fig. 7 but is not limited to being performed by this apparatus.

The apparatus comprises means for monitoring 110, means for selecting 120, and means for responding 130. The means for monitoring 110, means for selecting 120, and means for responding 130 may be a monitoring means, selecting means, and responding means, respectively. The means for monitoring 110, means for selecting 120, and means for responding 130 may be a monitor, selector, and responder, respectively. The means for monitoring 110, means for selecting 120, and means for responding 130 may be a monitoring processor, selecting processor, and responding processor, respectively.

The means for monitoring 110 monitors if a terminal receives a wakeup signal on a first beam (S110). The wakeup signal comprises fewer bits or radio resources than a paging message for paging the terminal. If the terminal receives the wakeup signal on the first beam (S110 = yes), the means for selecting 120 selects a resource out of a set of one or more resources (S120). Each resource of the set of one or more resources is associated with a respective beam of one or more beams. The set includes a first resource. The one or more beams include the first beam. The first resource is associated with the first beam. In this context, a resource is defined as a preamble comprising a preamble index and an occasion to transmit the preamble. The association to the first beam may be via the preamble, the preamble index, the occasion, or a combination thereof.

If the terminal receives the wakeup signal on the first beam (S110 = yes), the means for responding 130 instructs a transmitting device to transmit the first resource (S130).

The apparatus may further comprise means for obtaining configured to obtain the at least one of the associations of the plural resources with the two or more beams.

The apparatus may further comprise means for supervising configured to supervise if the terminal receives the paging message; means for replying configured to reply to the paging message by requesting a connection (such as a RRC connection) for the terminal.

Fig. 9 shows an apparatus according to an embodiment of the invention. The apparatus may be a cell (embodied by a base station such as a gNB, eNB etc.), or an element thereof. Fig. 10 shows a method according to an embodiment of the invention. The apparatus according to Fig. 9 may perform the method of Fig. 10 but is not limited to this method. The method of Fig. 10 may be performed by the apparatus of Fig. 9 but is not limited to being performed by this apparatus.

The apparatus comprises first means for transmitting 210, means for receiving 220, and second means for transmitting 230. The first means for transmitting 210, means for receiving 220, and second means for transmitting 230 may be a first transmitting means, receiving means, and second transmitting means, respectively. The first means for transmitting 210, means for receiving 220, and second means for transmitting 230 may be a first transmitter, receiver, and second transmitter, respectively. The first means for transmitting 210, means for receiving 220, and second means for transmitting 230 may be first a transmitting processor, receiving processor, transmitting processor, respectively. The first means for transmitting 210 transmits two or more paging wakeup signals through two or more beams (S210). The two or more paging wakeup signals indicate a paging message to be transmitted.

The means for receiving 220 receives a preamble associated with one of the two or more beams (S220).

The second means for transmitting 230 transmits the paging message using the one of the two or more beams (S230).

Fig. 11 shows an apparatus according to an embodiment of the invention. The apparatus may be a terminal such as a UE, an loT device, etc., or an element thereof. Fig. 12 shows a method according to an embodiment of the invention. The apparatus according to Fig. 11 may perform the method of Fig. 12 but is not limited to this method. The method of Fig. 12 may be performed by the apparatus of Fig. 11 but is not limited to being performed by this apparatus.

The apparatus comprises means for monitoring 310, first means for receiving 320, means for transmitting 330, and second means for receiving 340. The means for monitoring 310, first means for receiving 320, means for transmitting 330, and second means for receiving 340 may be a monitoring means, first receiving means, transmitting means, and second receiving means, respectively. The means for monitoring 310, first means for receiving 320, means for transmitting 330, and second means for receiving 340 may be a monitor, first receiver, transmitter, and second receiver, respectively. The means for monitoring 310, first means for receiving 320, means for transmitting 330, and second means for receiving 340 may be a monitoring processor, first receiving processor, transmitting processor, and second receiving processor, respectively.

The means for monitoring 310 monitors, by using two or more beams, a paging wakeup signal indicating a paging message to be transmitted (S310). The monitoring may be based on a first configuration message. The first configuration message may be received via a dedicated RRC message or via a broadcasted SIB.

The first means for receiving 320 receives the paging wakeup signal on one of the two or more beams (S320). The means for transmitting 330 transmits a preamble in response to the paging wakeup signal (S330). The preamble is associated with one of the two or more beams.

The second means for receiving 340 receives the paging message based on the one of the two or more beams (S340), i.e. using the one of the two or more beams.

Fig. 13 shows an apparatus according to an embodiment of the invention. The apparatus comprises at least one processor 810, at least one memory 820 including computer program code, and the at least one processor 810, with the at least one memory 820 and the computer program code, being arranged to cause the apparatus to at least perform at least one of the methods according to Figs. 6, 8, 10, and 12 and related description.

Embodiments of the invention are described for 5G networks operating in FR2 and beam- based operation. However, the invention is neither restricted to FR2 nor to beam-based operation. It may be employed with FR1 and/or without beam-based operation, too. It is not even restricted to 5G networks and may be employed in other 3GPP networks (such as 3G networks and 4G networks), too. For example, in these frequency ranges and/or networks, WUS may be used to determine an appropriate MCS for the paging message. Thus, robustness of the paging message is enhanced. Furthermore, the invention is not restricted to 3GPP networks and may be employed in other wireless networks having a paging function, too.

If the cell does not operate beam-based (i.e., the cell consists of a single “beam”), the resource may be fully or partly (only the preamble, or only the occasion) predefined. If the resource is fully predefined, gNB need not inform the UE on the resource. Also, in some example embodiments with one or more beams per cell, WUS may be used only to determine the MCS for the paging message. In these cases, the resource may be fully or partly predefined.

A UE is an example of a terminal. However, the terminal may be any device capable to connect to the (3GPP) radio network such as a MTC device, a loT device etc.

A gNB is an example of a base station. However, the base station may be any device capable to provide a base station function in the respective radio network, such as an eNB or a NodeB. One piece of information may be transmitted in one or plural messages from one entity to another entity. Each of these messages may comprise further (different) pieces of information.

Names of network elements, network functions, protocols, and methods are based on current standards. In other versions or other technologies, the names of these network elements and/or network functions and/or protocols and/or methods may be different, as long as they provide a corresponding functionality.

If not otherwise stated or otherwise made clear from the context, the statement that two entities are different means that they perform different functions. It does not necessarily mean that they are based on different hardware. That is, each of the entities described in the present description may be based on a different hardware, or some or all of the entities may be based on the same hardware. It does not necessarily mean that they are based on different software. That is, each of the entities described in the present description may be based on different software, or some or all of the entities may be based on the same software. Each of the entities described in the present description may be embodied in the cloud.

According to the above description, it should thus be apparent that example embodiments of the present invention provide, for example, a base station such as a gNB or eNB, or a component thereof, an apparatus embodying the same, a method for controlling and/or operating the same, and computer program(s) controlling and/or operating the same as well as mediums carrying such computer program(s) and forming computer program product(s). According to the above description, it should thus be apparent that example embodiments of the present invention provide, for example, a terminal such as a UE, or a component thereof, an apparatus embodying the same, a method for controlling and/or operating the same, and computer program(s) controlling and/or operating the same as well as mediums carrying such computer program(s) and forming computer program product(s).

Implementations of any of the above described blocks, apparatuses, systems, techniques or methods include, as non-limiting examples, implementations as hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

It is to be understood that what is described above is what is presently considered the preferred embodiments of the present invention. However, it should be noted that the description of the preferred embodiments is given by way of example only and that various modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

We Claim:

1. Apparatus comprising: first means for transmitting two or more first paging wakeup signals through two or more beams, the two or more first paging wakeup signals indicating a paging message to be transmitted; means for receiving a preamble associated with one of the two or more beams; and second means for transmitting the paging message using the one of the two or more beams.

2. The apparatus according to claim 1, wherein the second means for transmitting transmits the paging message using each beam of a subset of the two or more beams.

3. The apparatus according to any of claims 1 to 2, further comprising means for informing configured to inform a first terminal which preamble among a first set of preambles is associated with which one of the two or more beams.

4. The apparatus according to claim 3, wherein the means for informing is configured to inform the first terminal by broadcasting a system information and/or by transmitting a dedicated message to the first terminal.

5. The apparatus according to any of claims 3 and 4, wherein the first means for transmitting is further configured to transmit second paging wakeup signals using the two or more beams of a cell managed by the apparatus if a second terminal is to be paged; and the means for informing is configured to inform the second terminal which preamble among the first set of plural preambles is associated with which one of the two or more beams; wherein the second terminal is different from the first terminal; the second paging wakeup signals are different from the first paging wakeup signals; and each of the second wakeup signals comprises less radio resources than a paging message to be transmitted to the second terminal.

6. The apparatus according to any of claims 3 to 5, wherein the means for informing is configured to inform a third terminal different from the first terminal which preamble among a second set of plural preambles is associated with which one of the two or more beams, wherein the preambles of the first set are different from the preambles of the second set; and the first means for transmitting is further configured to transmit third paging wakeup signals using the two or more beams of the cell if the third terminal is to be paged.

7. The apparatus according to any of claims 1 to 6, further comprising means for estimating configured to estimate a reception quality of the received preamble; means for selecting configured to select a modulation and coding scheme for the paging message based on the estimated reception quality; means for instructing configured to instruct the second means for transmitting to modulate and code the paging message with the selected modulation and coding scheme.

8. Apparatus comprising: means for monitoring, by using two or more beams, a paging wakeup signal indicating a paging message to be transmitted; first means for receiving the paging wakeup signal on one of the two or more beams; means for transmitting a preamble in response to the paging wakeup signal, wherein the preamble is associated with one of the two or more beams; and second means for receiving the paging message based on the one of the two or more beams.

9. The apparatus according to claim 8, further comprising third means for receiving configured to receive association information between two or more preambles and the two or more beams.

10. The apparatus according to claim 9, wherein the third means for receiving is configured to receive the association information via a broadcasted system information and/or by a dedicated message to a terminal.

11. The apparatus according to any of claims 8 to 10, further comprising means for supervising configured to supervise if a terminal receives the paging message; and means for replying configured to reply to the paging message by requesting a connection (such as a RRC connection) for the terminal.

12. Method comprising: transmitting two or more first paging wakeup signals through two or more beams, the two or more first paging wakeup signals indicating a paging message to be transmitted; receiving a preamble associated with one of the two or more beams; and transmitting the paging message using the one of the two or more beams.

13. The method according to claim 12, wherein the paging message is transmitted using each beam of a subset of the two or more beams.

14. The method according to any of claims 12 to 13, further comprising informing a first terminal which preamble among a first set of preambles is associated with which one of the two or more beams.

15. The method according to claim 14, wherein the first terminal is informed by broadcasting a system information and/or by transmitting a dedicated message to the first terminal.

16. The method according to any of claims 14 and 15, further comprising transmitting second paging wakeup signals using the two or more beams of a cell managed by an apparatus performing the method if a second terminal is to be paged; and informing the second terminal which preamble among the first set of plural preambles is associated with which one of the two or more beams; wherein the second terminal is different from the first terminal; the second paging wakeup signals are different from the first paging wakeup signals; and each of the second wakeup signals comprises less radio resources than a paging message to be transmitted to the second terminal.

17. The method according to any of claims 14 to 16, further comprising informing a third terminal different from the first terminal which preamble among a second set of plural preambles is associated with which one of the two or more beams, wherein the preambles of the first set are different from the preambles of the second set; and transmitting third paging wakeup signals using the two or more beams of the cell if the third terminal is to be paged.

18. The method according to any of claims 12 to 17, further comprising estimating a reception quality of the received preamble; selecting a modulation and coding scheme for the paging message based on the estimated reception quality; instructing to modulate and code the paging message with the selected modulation and coding scheme.

19. Method comprising: monitoring, by using two or more beams, a paging wakeup signal indicating a paging message to be transmitted; receiving the paging wakeup signal on one of the two or more beams; transmitting a preamble in response to the paging wakeup signal, wherein the preamble is associated with one of the two or more beams; and receiving the paging message based on the one of the two or more beams.

20. The method according to claim 19, further comprising receiving configured to receive association information between two or more preambles and the two or more beams.

21. The method according to claim 20, wherein the association information is received via a broadcasted system information and/or by a dedicated message to a terminal.

22. The method according to any of claims 19 to 21, further comprising supervising if a terminal receives the paging message; and replying to the paging message by requesting a connection (such as a RRC connection) for the terminal.

23. A computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any of claims 12 to 22.

24. The computer program product according to claim 23, embodied as a computer-readable medium or directly loadable into a computer.