OA19351A - Device and method for controlling idle mode discontinuous reception - Google Patents

Abstract

The present disclosure relates to a wireless device and a method, for use in a wireless device, for controlling discontinuous reception, DRX, during idle mode. The method comprises selecting (S31) a default DRX cycle pattern for controlling operative instants during a DRX cycle and receiving (S32) from an access node, a first set of beams in the operative instants of the default DRX cycle pattern. The method further comprises determining (S33) reception quality metrics for respective beams and determining (S34), based on the reception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subsequent DRX cycle. The customized DRX cycle pattern is applied (S35) in the subsequent DRX cycle to receive a second set of beams.

Description

Aspects of the présent disclosure will be described more fully hereinafter with reference to the accompanying drawings. The apparatus and method disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like éléments throughout.

The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the disclosure. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be noted that the word “comprising” does not necessarily exclude the presence of other éléments or steps than those listed. It should further be noted that any reference signs do not limit the scope of the claims, that the example embodiments may be implemented at least in part by means of both hardware and software, and that several “means”, “units” or “devices” may be represented by the same item of hardware.

The various example embodiments described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments.

Within the context of this disclosure, the terms “wireless device” or “wireless terminal” encompass any terminal which is able to communicate wirelessly with an access node of a wireless network, as well as, optionally, with another wireless device, by transmitting and/or receiving wireless signais. Thus, the term “wireless device” encompasses, but is not limited to: a user equipment, e.g. an LTE UE, a mobile terminal, a stationary or mobile wireless device for machine-to-machine communication, an integrated or embedded wireless card, an extemally plugged in wireless card, a dongle etc. Throughout this disclosure, the term “user equipment” may sometimes be used to exemplify various embodiments. However, this should not be construed as limiting, as the concepts illustrated herein are equally applicable to other wireless devices. Hence, whenever a “user equipment” or “UE” is referred to in this disclosure, this should be understood as encompassing any wireless device as defined above.

In some embodiments the term “access node”, AN, is used and it can correspond to any type of access node or any network node communicating with a wireless device. In the context of this disclosure, the term access node is used to designate a node transmitting beams in a beam sweep to a receiving wireless device. Examples of access nodes are NodeB, base station, multi-standard radio, radio node, eNodeB, gNodeB, network controller, radio network controller, base station controller, relay, donor node controlling relay, base transceiver station, access point, transmission points, transmission nodes, nodes in distributed antenna system, DAS etc.

In support for higher frequencies in New Radio, NR, communication Systems, beamforming is an essential component. Using antenna arrays at access nodes, fairly regular grid-of-beams coverage patterns with tens or hundreds of candidate beams per node may be created. The coverage area of an individual beam from such an antenna array may be small, down to the order of some tens of meters in width. Outside the beam area, quality dégradations may occur quickly due to the limited coverage area of the beam. Beam sweep procedures are typically employed whereby a plurality of beams, e.g., comprising reference signais used for paging or synchronization or other type of system information signais, are sequentially transmitted in a respective beam directions from an access node.

In order for idle mode operations, e.g., paging procedure not to be the coverage-limiting factor in the next génération of communication Systems, the reference signais used for paging and synchronization will typically also hâve to use high-gain narrow beams. This means that the access node will typically hâve to transmit the signais multiple times, in different directions, to cover the geographical area to be served by an access node, AN. With some typical antenna configurations envisioned for the next génération communication Systems, sometimes referred to as 5G Systems, a narrow beam may cover only a small fraction of the entire geographical area (e.g. 1%) at a time, and consequently it may take substantial time to transmit the beam in ail directions needed, one or a few directions at a time.

The procedure of sequentially transmitting the beam in ail necessary directions is referred to as a beam sweep or beam scan. “Necessary directions” here means ail directions where coverage is desired. Figure la illustrâtes a beam sweep comprising beams A-D and transmitted from an access node 20 having one transmission point. In the NR Systems, it is also expected that one single access node might hâve several transmission points, as illustrated by access nodes 20a and b in Figure 1b, where a first access node 20a transmits beams A-D to a receiving wireless device and a second access node 20b transmits beams E-F to the wireless device. A beam sweeping procedure is anticipated during paging of wireless devices or other types of transmission of unsolicited data toward an idle wireless device, e.g., other types of broadeast system information distribution. In high frequency bands, where narrow beams may be required, the beams in a sweep may add up to a substantial number. The paging information may be transmitted in one or a few OFDM symbols per beam.

The methods and wireless device aspects presented in this disclosure addresses the conflicting demands between wireless device energy consumption and on demand accessibility to a wireless device, i.e., the need for prompt and successful communication also with idle mode devices. In particular, the présent disclosure reduces energy consumption in an idle mode wireless device without compromising the ability for the wireless device to receive paging information, unsolicited system information and/or broadcast information through a receiver configured to operate in according to a discontinuous réception, DRX, cycle. The basic idea is to configure a wireless device to control a discontinuous réception, DRX, set up, so that a receiver in the wireless device is activated only during the limited number of beams that the wireless device is capable of distinguishing in the beam sweep. Thus, a more energy efficient réception procedure is established within a wireless device without jeopardizing the on demand accessibility.

Tuming to Figure 2, discontinuous réception, DRX, in a wireless device is briefly discussed to further explain the basic concept of beam sweep réception during idle mode. Figure 2 further details the présentation of the beam sweep illustrated in Figure la. The discussion will be made for the beam sweep comprising paging information; however, similar principles are of course also applicable for beam sweeping procedures comprising transmission and réception of other types of unsolicited system information to an idle mode wireless device. The beam sweep is periodically performed according to a predetermined cycle, and the DRX receiver of the wireless device is activated in accordance with this cycle, hereinafter referred to as DRX cycle.

An access node 20, e.g., an eNodeB or gNodeB, transmits paging information in beams A-D with different directions; each beam corresponding to OFDM symbol sets A, B, C, D. The beams are transmitted in a beam sweep where transmission of beam A occurs in a time instant different from transmission of beams B-D, e.g., in a time instants that précédés the time instants when beams B to D are transmitted. The OFDM symbol set may comprise a single OFDM symbol. An idle mode wireless device 40 is configured for discontinuous réception, DRX, according to a DRX cycle; enabling réception in receiver circuitry during operative instants for the receiver. The operative instants recur according to a DRX cycle pattern, e.g., every 100-10 000 ms, determined for the wireless device based on a paging periodicity used by the access node.

At time Tl, the wireless device 40 is in a beam direction of beam B. Thus, at Tl, réception of beam B would be superior to réception of the other narrow beams A, C and D illustrated for the beam sweep. As visualized in Figure 2, it is unlikely that the wireless device would be able to receive beam D. In accordance with the basic principles of the présent disclosure, as mentioned above, it would be bénéficiai from an energy saving perspective to adapt the DRX cycle pattern (i.e., a receiver-on window) for the wireless device receiver circuitry so that the receiver circuitry is active just long enough to receive beam B. Figure 2 illustrâtes how a receiver-on window is adapted so that the receiver is tumed on one OFDM symbol set prior to beam B (i.e., for the time instant of beam A) and tumed off one OFDM symbol set after beam B (i.e., for the time instant of beam C). Initially, a receiver window may be open for réception through the entire beam sweep, but for the illustrated scénario this would still imply receipt of beams A-C at Tl.

As will be further discussed and disclosed below, a wireless device at Tl would be able to limit a réception window to just accommodate réception of beam B or to also accommodate réception of a few neighboring beams.

At time T2, the wireless device has moved and beam B is no longer the best beam from a receiver perspective, as visualized by the disclosed metrics. Instead, beam C appears to represent the best beam. Furthermore, beam A is now barely perceivable and does no longer contribute in the communication of paging information. Accordingly, the beam réception window should now be adapted to accommodate réception of beam C and possibly neighboring beams. The determined metrics are used to détermine an updated beam réception window accommodating beams B-D from time T3. The accommodation of beams B-D is enabled by delaying the receiver-on time relative to a reference time of the DRX cycle, e.g., the start time for a DRX cycle.

A method for controlling discontinuous réception, DRX, in a wireless device will now be presented. Figure 3 illustrâtes, in a flowchart, exemplary operations performed in a wireless device when operating in a wireless communication network. The disclosed method provides a solution for controlling DRX during idle mode. The wireless device selects S31 a default DRX cycle pattern for controlling operative instants during a DRX cycle. According to an aspect of the disclosure, an operative instant is a beam réception window periodically recurring during a DRX cycle. According to one alternative aspect of the disclosure, the default DRX cycle pattern is a state of the art DRX window comprising a plurality of time consecutive operative instants; the state of the art DRX window being activated at a receiver start time and deactivated at a receiver off time or following a predetermined duration, and recurring with each DRX cycle. Thus, according to this aspect, the wireless device initially receives during the entire DRX window. According to another alternative aspect of the disclosure, the default DRX cycle pattern comprises a plurality of operative instants having a temporal duration less than a state of the art DRX window and selected following the steps of determining S31a a default timing for receiving beams comprised in a beam sweep during the DRX cycle, and assigning S31b a start time, and a duration or end time for each operative instant of the default DRX cycle pattern based on the determined default timing. Thus, according to this aspect, the wireless device détermines a first approximate timing, i.e., default timing, and selects a default DRX cycle pattern by selecting a receiver start time and a receiver off time or receiver duration, based on the approximate timing. As one example, the wireless device initially detects paging signais during an entire DRX paging monitoring window, i.e., DRX window and détermines the timing for the best beam, i.e., the timing for the best sweep direction.

In a subséquent step, the wireless device receives S32, from an access node, a first set of beams in the operative instants of the default DRX cycle pattern. Applying the selected default DRX cycle pattern in a DRX cycle, the wireless device receives the first set of beams; the first set of beams comprised in a beam sweep received from an access node with a DRX cycle periodicity and each beam of the first set of beams comprising at least one OFDM symbol. As mentioned above, the default DRX cycle pattern is configured to accommodate réception of a plurality of beams comprised in a beam sweep. Thus, the présent disclosure is particularly applicable in transmissions using orthogonal frequency division multiplexing, OFDM, as a method of encoding digital data, and wherein the transmissions are performed as beam sweeps in one or two dimensions; transmitting a plurality of beams with different directions in each beam sweep.

According to an aspect of the disclosure, réception S32 from an access node, of a first set of beams in the operative instants of the default DRX cycle pattern comprises receiving the first set of beams over a plurality of DRX cycles. Fractions of an entire DRX window may be swept in a random or sequential order, so that réception during the plurality of DRX cycles comprises receiving the first set of beams during at least partially non-overlapping subsets of the operative instants. Sweeping a plurality of at least partially non-overlapping fractions of the entire DRX window would resuit in a beam sweep procedure whereby réception of the first set of beams, e.g., ail beams in the beam sweep, is accommodated in the time period corresponding to said plurality of DRX cycles.

Upon receipt of a first set of beams in the operative instants of the default DRX cycle pattern, the wireless device détermines S33 réception quality metrics for respective beams. According to an aspect of the disclosure, each beam comprises paging information, unsolicited system information or broadcast information. Réception quality for respective beams may be determined in a number of ways, e.g., by measuring received signal strength for a given beam or information comprised in the beam, e.g., as a set of resource éléments in one or more OFDM symbols of the beam. According to aspects of the disclosure, the determining of réception quality metrics for respective beams comprises, decoding a set of resource éléments in a first OFDM Symbol received in an operative instant of the default DRX cycle pattern and determining a first metric associated to the decoding performance. A corresponding set of resource éléments are decoded in at least a second OFDM symbol received in an operative instant of the default DRX cycle pattern, where the OFDM symbols may be received in a continuous operative instant having a duration to accommodate réception of a plurality of OFDM symbols, or in discrète operative instants, each OFDM symbol received in a respective operative instants. A second metric associated to the decoding performance when decoding resource éléments in the at least second OFDM symbol is determined. Simple metrics that are considered as représentative of the decoding performance comprise soft value metrics, e.g., decoding error likelihood estimate of a paging signal. Other metrics may be determined from a corrélation with first known symbols (e.g., with pilot symbols/signals) that are transmitted in some resource éléments, and wherein the metric in this case is related to a corrélation matching performance, i.e., how closely the received signal resembles a known pilot signal.

According to other aspects of the disclosure, the determining S33 of réception quality metrics comprises receiving beams in the operative instants of the default DRX cycle pattern during a plurality of DRX cycles; determining quality metrics for respective beams in each of the plurality of DRX cycles, and determining the réception quality metrics by filtering the quality metrics from the plurality of DRX cycles. Thus, filtering over several obtained first and second decoding metrics may be used in some embodiments in the determining of the réception quality metrics.

According to aspects of the disclosure, the first and second OFDM symbols may be adjacent. However, the disclosed method is also applicable in when beam sweeping is made in two dimensions and in such instances the first and second OFDM symbols may very well be nonadjacent. Furthermore, the monitored OFDM symbol sets may be non-adjacent so that the operative instants in the customized DRX cycle pattern are time discrète. Receiver circuitry of the wireless device may then be switched off between monitored OFDM symbol sets as accommodated by the applied DRX cycle pattern.

Based on the réception quality metrics, the wireless device performs the step of determining S34 a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle. In its most basic embodiment, the customized DRX cycle pattern présents an updated time on and time off or duration for receiver circuitry in the wireless device. When the method is initiated using a state of the art DRX window as default DRX cycle pattern, use of the customized DRX cycle pattern will imply that the DRX receiver is activated during a shorter time period of a DRX cycle as compared to the state of the art DRX window. As mentioned previously, the beams are comprised in respective beam sweeps transmitted from an access node with a DRX cycle periodicity and wherein each beam comprises at least one OFDM symbol. According to aspects of the disclosure, the default DRX cycle pattern is configured to accommodate réception of a plurality of beams comprised in a beam sweep and the customized DRX cycle pattern is configured to accommodate a subset of the beams comprised in the beam sweep; thereby achieving the benefits of reduced energy consumption during idle mode of the wireless device. However, if the default DRX cycle pattern has been selected based on an initial approximate timing to accommodate réception of beams within a time instant determined from the approximate timing, the customization of the DRX cycle pattern could also imply an extension of the receiver window.

According to other aspect, the determining S34 of the customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle comprises selecting one or more time intervals in a beam réception window of the default DRX cycle pattern; each time interval being determined by a start time, and a duration or end time; and wherein the selecting is made by a comparison of determined metrics. According to further aspects of the disclosure, the customized DRX cycle pattern is determined to comprise operative instants to accommodate beams having qualitatively similar réception quality metrics. Thus, when there are a number of beams perceived to be received with equal or close to equal réception quality, the customized DRX cycle pattern will comprise a larger set of operative instants as compared to the situation when one beam is clearly better than the others. According to aspects of the disclosure, the customized DRX cycle pattern should comprise the best beams, i.e., beams qualified to be accommodated through their determined réception quality metrics. According to further aspects of the disclosure, the customized DRX cycle pattern also accommodâtes one or more neighboring beams of such best beams.

The customized DRX cycle pattern is applied S35 in a subséquent DRX cycle, e.g., the first subséquent DRX cycle for which application is possible or a later DRX cycle, to receive a second set of beams. In accordance with aspects presented above, the second set of beams is comprised in a beam sweep transmitted from an access node with a DRX cycle periodicity and wherein each beam comprises at least one OFDM symbol. Applying the customized DRX cycle pattern in a later DRX cycle provides an opportunity to verify the customized DRX cycle pattern by repeating the steps of receiving beams in operative instants of the default DRX cycle pattern; and determining the réception quality metrics by filtering quality metrics from a plurality of DRX cycles.

According to an aspect of the disclosure a second set of beams are received S36, from an access node, in the operative instants of the customized DRX cycle pattern when applying the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams. According to an aspect of the disclosure, the customized DRX cycle pattern is used also in further subséquent DRX cycles to receive further set of beams, e.g., when the access nodes transmits a beam sweep comprising paging information.

According to other aspects, the process of determining a customized DRX cycle pattern may also be repeated; either to refîne the determined customized DRX cycle pattern further or to allow for tracking of a wireless device that is in a mobility state. According to aspects of the disclosure, the wireless device détermines S37 fulfillment of a répétition condition, and when the condition is fulfilled, repeats the steps of determining S33 réception quality metrics for respective beams, determining S34 the customized DRX cycle pattern, and applying S35 the customized DRX cycle pattern, or retuming to the default DRX cycle pattern. The répétition condition could be based on wireless device mobility, determining fulfillment of the répétition condition when the wireless device is stationary or in a low mobility state. The répétition condition could also be set to reflect a need for periodic reassessment of the customized DRX cycle pattern, e.g., that the process is repeated during a predetermined number of DRX cycles to verify a previous assessment or according to a specified periodicity. Finally, the répétition condition may be set so that the full process is repeated when the répétition condition is no longer fulfilled, e.g., after a predetermined number of DRX cycles to ensure that the ability to receive the access node transmission is not compromised. The process is repeated by reverting to the step of selecting S31 the default DRX cycle pattern.

The disclosed method is foremost intended for a wireless device that is in a state of low mobility, but is not limited to low mobility applications. A Doppler estimator or positioning information from a GPS unit in the wireless device could be used to detect the mobility state of the wireless device. As mobility increases, the need to update the customized DRX cycle pattern also increases. Thus, a répétition condition as mentioned above comprises a mobility state of the wireless device so that the repeating is performed when the wireless device is stationary or in a low mobility state.

Occasionally, the wireless device may be configured to revert to réception according to the default DRX cycle pattern, e.g., during an entire DRX window in a DRX cycle. The above disclosed process may then be resumed.

Notably, the transmission of the beam sweep is from the access node is unaffected by the disclosed method, it is the energy efficient extraction of beams in a receiving wireless device that is addressed through the above disclosed method.

The proposed method will now be exemplified with an embodiment where the access node beam sweep occurs in one dimension, e.g., as suggested in Figure 2. The beams of the beam sweep, i.e., OFDM symbol sets, comprise paging information. When performing the beam sweep in one dimension, each transmitted OFDM symbol set is adjacent to the next OFDM symbol set. Since usually there is only one beam (or a few) that the wireless device can hear, most of the réception window is empty for the wireless device and the long receiver operation at each paging cycle contributes to redundant idle mode power consumption. According to the general concept of the disclosure, explained above, the wireless device performs a decoding of information, e.g., decoding the paging information, received from multiple beams in a sweep, computes a metric for each of the received beams (OFDM symbol(s)) and adapts a receiver window position and/or duration according to the determined metric thereby determining a customized DRX cycle pattern.

The DRX réception of the wireless device initially follows a default DRX cycle pattern that may be determined from a first paging timing and a corresponding receiver-on time. This détermination of the default DRX cycle pattern may be made by a wide search or scan over a large number of beams and corresponding paging OFDM symbol sets. During the sweep, when the access node steps through a set of narrow beam directions, neither the wireless device nor the access node is generally aware of which of the beams in the sweep is best heard by the wireless device. The DRX window, i.e., the default DRX cycle pattern, must thus be specified such that the entire beam sweep is accommodated, and the wireless device must receive data during the entire sweep duration. The default DRX cycle pattern is determined as a “receiver-on” time window, e.g., corresponding to a plurality of adjacent time instants, also denominated as operative instants, when the receiver is activated to receive the transmitted beams.

The wireless device then décodés a first set of resource éléments corresponding to paging information in a first and second set of OFDM symbols received with the default DRX cycle pattern. The wireless device détermines first and second metrics for decoded resource éléments in corresponding first and second set of OFDM symbols, e.g., by determining the réception quality for the decoded paging information or by determining a corrélation between resource éléments corresponding to pilot signais used for estimating and equalizing the radio channel for paging détection.

The computed first and second metric are compared and if the second metric represents a better resuit than the first metric, the wireless device selects a customized DRX cycle pattern to control activation of the receiver circuitry during a subséquent DRX cycle. In a scénario where one main OFDM symbol set is determined to provide the best réception quality metric, the customized DRX cycle pattern corresponds to a “receiver-on” wake up time and end time so that the receiver is activated just long enough to receive the beam of the main OFDM symbol set, and possibly neighboring beams.

In summary, the above wireless device may operate according to the above disclosed exemplifying embodiment by:

• initially receive during an entire DRX window.

• détermine the best beam timings in relation to the DRX window beginning.

• in subséquent DRX cycles, delay receiver wake-up with respect to the DRX window beginning and shutting down before the end of the window; the window is kept open just enough to receive the best beams (for data réception) and their neighbor beams (for tracking).

• after each or some DRX cycle, update the best beam and tracking info to be used during the next DRX cycle; and • occasionally, revert to réception during the entire DRX window to detect new possible best beam timings.

In accordance with an alternative embodiment, the default DRX cycle pattern could also be implemented by sweeping a plurality of fractions of an entire DRX window in a random or sequential order. Sweeping a plurality of at least partially non-overlapping fractions of the entire DRX window would resuit in ail non-active beams having been searched after a time period corresponding to a plurality of DRX cycles. When reverting to réception according to the default DRX cycle pattern, the wireless device could revert to réception in a plurality of fractions of an entire DRX window to ensure that a réception window, i.e., the customized DRX cycle pattern, continues to accommodate a best beam and one or more neighbor beams.

Embodiments of the présent disclosure, e.g., as explained with reference to Figure 3, are not limited to beam sweeping in one dimension. In embodiments where the beam sweeping is made in two dimensions, the next closest may correspond to a second OFDM symbol set that is not adjacent to the first OFDM symbol set. Hence, the time window may not only be adapted in time, but the length of an operative instant in the RX on time window may be changed if second metric larger than first metric. In another embodiment, due to similar reasons as above, operative instants of the RX on window may be non-contiguous, i.e., the OFDM symbols sets that are monitored may be non- adjacent, and the receiver circuitry is switched off between monitored OFDM symbols sets.

In some of the above examples, the method for controlling discontinuous réception has been described for the example of paging. However, the disclosure is not limited to paging, but is also applicable to other beam swept System information or other control plane information réception.

Furthermore, it should be noted that the various example embodiments described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact dises (CDs), digital versatile dises (DVD), etc. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed in Figure 3. The particular sequence of such exécutable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

Figure 4a is an example configuration of a wireless device 40, which may incorporate some of the example embodiments discussed above. The wireless device 40 is configured for controlling discontinuous réception, DRX, during idle mode. As shown in Figure 4, the wireless device comprises receiver circuitry 41 arranged for réception of radio signais received as beams in a beam sweep from a transmitting access node. It should be appreciated that the receiver circuitry 41 may be comprised as any number of receiving units or circuitry. It should further be appreciated that the receiver circuitry 41 may be in the form of any input communications port known in the art.

The wireless device further comprises processing circuitry arranged to control operation of the wireless device. In particular, the processing circuitry 42 is configured to cause the wireless device to select a default DRX cycle pattern for controlling operative instants during a DRX cycle and to receive, by means of the receiver circuitry, from an access node, a first set of beams in the operative instants of the default DRX cycle pattern. The processing circuitry 42 is further configured to détermine réception quality metrics for respective beams, to détermine, based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle, and to apply the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams.

According to an aspect of the disclosure, the processing circuitry comprises a processor 42a and a memory 42b. The processor 42a may be any suitable type of computation unit or circuit, e.g. a microprocessor, digital signal processor, DSP, field programmable gâte array, FPGA, or application spécifie integrated circuit, AS IC or any other form of circuitry. It should be appreciated that the processing circuitry need not be provided as a single unit but may be provided as any number of units or circuitry.

The memory 42b may further be configured to store received data and/or exécutable program instructions. The memory 42b may be any suitable type of computer readable memory and may be of volatile and/or non-volatile type.

Figure 4b also illustrâtes an embodiment of a wireless device 40 configured for controlling discontinuous réception, DRX, during idle mode. The wireless device comprises a cycle pattern sélection module 421 for selecting a default DRX cycle pattern for controlling operative instants during a DRX cycle; a beam réception module 422 for receiving a first set of beams in the operative instants of the default DRX cycle pattern; a metrics détermination module 423 for determining réception quality metrics for respective beams; a DRX cycle pattern détermination module 424 for determining, based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle; and a cycle pattern application module 425 for applying the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams.

The description of the example embodiments provided herein hâve been presented for purposes of illustration. The description is not intended to be exhaustive or to limit example embodiments to the précisé form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various alternatives to the provided embodiments. The examples discussed herein were chosen and described in order to explain the principles and the nature of various example embodiments and its practical application to enable one skilled in the art to utilize the example embodiments in various manners and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in ail possible combinations of source nodes, target nodes, corresponding methods, and computer program products. It should be appreciated that the example embodiments presented herein may be practiced in combination with each other.

Claims (25)

1. A method, for use in a wireless device, for controlling discontinuous réception, DRX, during idle mode, the method comprising:

selecting a default DRX cycle pattern for controlling operative instants during a DRX cycle, receiving, from an access node, a first set of beams in the operative instants of the default DRX cycle pattern;

determining réception quality metrics for respective beams;

determining, based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle; and applying the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams.

2. The method of claim 1, wherein the first and second set of beams are comprised in respective beam sweeps transmitted from an access node with a DRX cycle periodicity and wherein each beam comprises at least one OFDM symbol.

3. The method of claim 2, wherein the default DRX cycle pattern is configured to accommodate réception of a plurality of beams comprised in a beam sweep and the customized DRX cycle pattern is configured to accommodate a subset of the beams comprised in the beam sweep.

4. The method of claims 2 or 3, wherein an operative instant is a beam réception window periodically recurring during a DRX cycle.

5. The method of claim 4, wherein the step of selecting a default DRX cycle pattern for controlling operative instants during a DRX cycle comprises:

determining a default timing for receiving beams comprised in a beam sweep during the DRX cycle, and assigning a start time, and a duration or end time for each beam réception window of the default DRX cycle pattern based on the determined default timing.

6. The method of claim 4, wherein the receiving, from an access node, of a first set of beams in the operative instants of the default DRX cycle pattern comprises receiving the first set of beams over a plurality of DRX cycles, wherein réception during the plurality of DRX cycles comprise receiving the first set of beams during at least partially non-overlapping subsets of the operative instants.

7. The method of any of the preceding claims, wherein each beam comprises paging information, unsolicited system information or broadcast information.

8. The method any of claims 2-7, wherein the determining of réception quality metrics for respective beams comprises, for at least two OFDM symbols received in respective beams decoding a first set of resource éléments in at least a first OFDM symbol, and determining a first metric associated to the decoding performance; and decoding a first set of resource éléments in at least a second OFDM symbol and détermine corresponding second metric associated to the decoding performance.

9. The method of claim 8, wherein the at least two OFDM symbols are received in an OFDM réception window associated with the default timing.

10. The method of claim 8, wherein a metric is determined as a decoding error likelihood estimate of the set of resource éléments.

11. The method of claim 8, wherein a metric is determined based on a corrélation matching performance for a corrélation of the decoded resource éléments with pilot symbols transmitted in the resource éléments.

12. The method of claims 8-11, wherein the determining of réception quality metrics comprises receiving beams in the operative instants of the default DRX cycle pattern during a plurality of DRX cycles; determining quality metrics for respective beams in each of the plurality of DRX cycles, and determining the réception quality metrics by filtering the quality metrics from the plurality of DRX cycles

13. The method of claims 8-11, wherein the at least second OFDM symbols are adjacent to the first OFDM symbol.

14. The method of claims 8-11, wherein the at least second OFDM symbols are non-adjacent to the first OFDM symbol.

15. The method of any of claims 6-14, wherein the determining, based on the réception quality metrics, of the customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle comprises selecting a subset of Beam réception Windows of the default DRX cycle pattern; each beam réception window being determined by a start time, and a duration or end time; and wherein the selecting is made by a comparison of determined metrics.

16. The method of any of claims 8-15, wherein the customized DRX cycle pattern is determined to comprise operative instants to accommodate beams having qualitatively similar réception quality metrics.

17. The method of any of claims 8-16, wherein the customized DRX cycle pattern is determined comprise operative instants to accommodate neighboring beams of the beams qualified to be accommodated through their determined réception quality metrics.

18. The method of any of claims 15-17, further comprising:

receiving, from an access node, a second set of beams in the operative instants of the customized DRX cycle pattern;

determining fulfillment of a répétition condition, and

i. when the répétition condition is fulfilled, repeating the method from the step of determining réception quality metrics for respective beams, or ii. when the répétition condition is not fulfilled, repeating the method from the step of selecting a default DRX cycle pattern for controlling operative instants during a DRX cycle.

19. The method of any of the preceding claims, where a subséquent DRX cycle is a next DRX cycle.

20. The method of claim 18 or 19, where the répétition condition comprises a mobility state of the wireless device and wherein the répétition condition is fulfilled when the wireless device is stationary or in a low mobility state.

21. The method of any of claims 18 to 20, where the répétition condition comprises a predetermined number of DRX cycles and wherein the répétition condition is fulfilled when the subséquent DRX cycle belongs to the predetermined number of DRX cycles.

22. A computer readable storage medium, having stored thereon a computer program which, when executed in a wireless device, causes the wireless device to execute the methods according to any of claims 1-21.

23. A wireless device configured for controlling discontinuous réception, DRX, during idle mode, the wireless device comprising:

- receiver circuitry arranged for réception of radio signais received as beams in a beam sweep from a transmitting access node;

- processing circuitry configured to, using the receiver circuitry, cause the wireless device to:

• select a default DRX cycle pattern for controlling operative instants during a DRX cycle, • receive, from an access node, a first set of beams in the operative instants of the default DRX cycle pattern;

• détermine réception quality metrics for respective beams;

• détermine, based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle; and • apply the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams.

24. The wireless device of claim 23, wherein the processing circuitry comprises a processor and a memory containing instructions exécutable by said processor.

25. A wireless device configured for controlling discontinuous réception, DRX, during idle mode, the wireless device comprising:

a cycle pattern sélection module for selecting a default DRX cycle pattern for controlling operative instants during a DRX cycle;

a beam réception module for receiving a first set of beams in the operative instants of the default DRX cycle pattern;

5 - a metrics détermination module for determining réception quality metrics for respective beams;

a DRX cycle pattern détermination module for determining, based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle; and

10 - a cycle pattern application module for applying the customized DRX cycle pattern in the subséquent DRX cycle to receive a second set of beams.

ABSTRACT

The présent disclosure relates to a wireless device and a method, for use in a wireless device, for controlling discontinuous réception, DRX, during idle mode. The method comprises selecting (S31) a default DRX cycle pattern for controlling operative instants during a DRX cycle and 5 receiving (S32) from an access node, a first set of beams in the operative instants of the default DRX cycle pattern. The method further comprises determining (S33) réception quality metrics for respective beams and determining (S34), based on the réception quality metrics, a customized DRX cycle pattern for controlling operative instants during a subséquent DRX cycle. The customized DRX cycle pattern is applied (S35) in the subséquent DRX cycle to receive a second 10 set of beams.